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http://mathoverflow.net/questions/48394/an-operator-norm-version-of-siegels-lemma
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# An operator-norm version of Siegel's Lemma
Is there a kind of Siegel's Lemma saying that if $M$ is a small-height'' integer matrix, then there is a "small-height" vector $x$ with $\|Mx\|=\|M\|\|x\|$? (Here $\|Mx\|$ and $\|x\|$ denote the Euclidean norms, and $\|M\|$ is the operator norm, induced by the Euclidean norm.)
I am particularly interested in the case where the elements of $M$ are restricted to the values $0$ and $1$; what can be said in this situation about the vectors $x$ with $\|Mx\|=\|M\|\|x\|$ (or with the weaker property that, say, $\|Mx\|\ge 0.1\|M\|\|x\|$)? Can one guarantee that some of these vectors have, in some reasonable sense, a low height?
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For beotians, could you give a formulation of Siegel's Lemma ? Thanks. – Denis Serre Dec 6 '10 at 6:50
@Denis: Wikipedia has a brief and to-the-point article on Siegel's Lemma. (For some technical reason, I have troubles inserting the link.) – Seva Dec 6 '10 at 9:38
Seva, without refereeing to your wanted case, I would suggest you looking at: Iskander Aliev, Siegel's lemma and sum-distinct sets. Discrete Comput. Geom. 39 (2008), no. 1-3, 59–66 (dx.doi.org/10.1007/s00454-008-9059-9), and Lenny Fukshansky, Siegel's lemma with additional conditions. J. Number Theory 120 (2006), no. 1, 13–25 (dx.doi.org/10.1016/j.jnt.2005.11.009). Iskander is an expert in all possible versions of Siegel's lemma... – Wadim Zudilin Dec 6 '10 at 11:45
@Wadim: thanks for the references. I will check them but, honestly, I think the similarity between my question and Siegel's Lemma is merely conceptual. – Seva Dec 7 '10 at 6:36
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2015-07-28 01:45:37
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https://testbook.com/question-answer/the-distance-of-1-cm-on-a-map-represents-7-m-on-th--6089720d3b6a2faa19694cd3
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# The distance of 1 cm on a map represents 7 m on the ground. If the distance between the school and the home of the student is 700 m on the ground, then their distance on the map will be
1. 100 cm
2. 10 cm
3. 70 cm
4. 17 cm
Option 1 : 100 cm
## Detailed Solution
Given:
The distance of 1 cm on the map represents 7 m on the ground.
Calculation:
As, 1 cm represents a distance of 7 m on the ground
⇒ 1 m distance on the ground is represented by $$1\over7$$ cm
The distance between the school and home of the student is 700 m
⇒ 700 m distance on the ground is represented by $$1\over7$$ × 700 cm = 100 cm
∴ 700 m distance in the map is represented by 100 cm.
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2021-12-01 19:12:43
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https://socratic.org/questions/58eb4553b72cff1036e0cbf9
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# How hydrochloric acid reduce PbCl_4 to lead metal, and oxidize chloride to chlorine gas?
Apr 10, 2017
$P b {O}_{2} \left(s\right) + 4 H C l \left(a q\right) \rightarrow P b C {l}_{2} \left(s\right) + 2 {H}_{2} O \left(l\right) + C {l}_{2} \left(g\right)$
#### Explanation:
$P \left(+ I V\right)$ is reduced to $P b \left(+ I I\right)$:
$P {b}^{4 +} + 2 {e}^{-} \rightarrow P {b}^{2 +}$ $\left(i\right)$
Chloride ion is oxidized to chlorine gas:
$C {l}^{-} \rightarrow \frac{1}{2} C {l}_{2} \left(g\right) + {e}^{-}$ $\left(i i\right)$
And thus $\left(i\right) + 2 \times \left(i i\right) :$
$P {b}^{4 +} + 2 C {l}^{-} + 2 {e}^{-} \rightarrow P {b}^{2 +} + C {l}_{2} \left(g\right) + 2 {e}^{-}$
Which is balanced with respect to mass and charge.
We can write a more conventional stoichiometric equation, by substituting the ions for the parent compounds.......
$P b {O}_{2} + 4 H C l \rightarrow P b C {l}_{2} \left(s\right) \downarrow + C {l}_{2} \left(g\right) \uparrow + 2 {H}_{2} O$
Is this balanced with respect to mass and charge?
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2021-10-28 09:23:00
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http://ibmaths4u.com/viewtopic.php?f=16&t=117
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## MYP Mathematics, midpoint
number, algebra, geometry and trigonometry, statistics and probability, discrete mathematics.
### MYP Mathematics, midpoint
MYP Mathematics, midpoint formula
How can we find the coordinates of the midpoint of line segment BC where B(10,50) and C(20,30) ?
Thanks
Lucas
Posts: 0
Joined: Mon Jan 28, 2013 8:05 pm
### Re: MYP Mathematics, midpoint
MYP Mathematics, midpoint formula
The coordinates of the midpoint of a line segment defined by the points $A(x_{1}, y_{1})$ and $B(x_{2}, y_{2})$ is given by the following formula:
$(x_{m}, y_{m} )=( \frac{x_{1}+x_{2}}{2},\frac{y_{1}+y_{2}}{2} )$
Applying the above formula in our case we have
$(x_{m}, y_{m} )=( \frac{10+20}{2},\frac{50+30}{2} )=$
$=( \frac{30}{2},\frac{80}{2} )$
$=( 15, 40)$
Hope these help!
miranda
Posts: 268
Joined: Mon Jan 28, 2013 8:03 pm
### Re: MYP Mathematics, midpoint
thanks miranda!!
Lucas
Posts: 0
Joined: Mon Jan 28, 2013 8:05 pm
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2018-07-19 05:43:43
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https://www.nature.com/articles/s41598-020-65194-8?error=cookies_not_supported&code=6cf70a95-cce4-404a-8ac0-d304e40068b4
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## Introduction
Marine environmental conditions vary on multiple temporal scales, and under the influence of climate change, these conditions are likely to change in frequency and magnitude. Seawater temperature is a crucial environmental factor in determining drivers of coral physiology and coral reef ecology1,2,3,4. Mass coral bleaching and mortality, caused predominately by abnormally warm events5,6,7 and sometimes by anomalously cold ones8,9, highlight the importance of understanding and forecasting seawater temperature variations and extremes10,11,12.
The effect of seasonal and monthly (lunar) variations in seawater temperature on coral reef ecosystems is well recognized13, yet temporal variation on a daily to weekly or shorter scales is rarely studied7. This is unfortunate given that corals exposed to large daily temperature fluctuations may possess elevated thermal tolerance12,14. The risk of coral bleaching may also be reduced by high-frequency temperature variability12. The largest temperature fluctuations in coral reefs are often associated with intermittent upwelling induced by internal waves7,12,13. Since upwelled cold water has the capacity to act as a buffer from thermal stress during abnormally warm events, these reefs may become refuges in a warming ocean14,15,16,17. Corals inhabiting intermittent upwelling environments have shown a variety of benefits, ranging from improved growth18 and energy reserves19, to enhanced metabolic plasticity20, and site-specific physiological acclimatization21,22. Yet, the influence of mesoscale eddies on corals in these dynamic environments remains unclear23,24.
Fringing coral reefs are well-developed along the coast and down to ~30 m depth in Nanwan Bay (NW), a small semi-enclosed bay approximately 15 km wide, at the southern tip of Taiwan (Fig. 1). The topography of NW is canyon-like, oriented in a northwest to southeast direction, with a maximum depth of ~80 m. Environmental conditions in this region show seasonal, lunar, and tidal variations due to several oceanographic and weather-related factors, including the influence of the South China Sea (SCS), Kuroshio current, tides, internal wave-induced upwelling, monsoons, and typhoons4,13,25,26,27. NW is predominately influenced by the SCS, which has a comparatively shallow thermocline and typically cooler temperature than the Kuroshio current26. The Kuroshio current typically flows along the east coast of Taiwan, although its path shifts and traverses the Luzon Strait in winter. The Kuroshio current’s path fluctuates frequently over weeks to months due to impinging mesoscale eddies. Some eddy-Kuroshio interactions east of Taiwan can strongly affect the Luzon Strait, for example, by forming a large anticyclonic “loop current”27,28. The largest known oceanic internal waves globally are generated within the ridges of the Luzon Strait south of NW29. Despite these locally unique phenomena, the role that mesoscale eddies play in influencing temperatures in NW is unknown.
NW is subject to significant cold-water intrusions, coinciding with tidal frequencies, with daily temperature differences exceeding 5 °C25,30. Several unusual biophysical phenomena associated with these temperature fluctuations have been reported. Three particularly unique examples include: (1) an unusual cold event in 1988, which decreased the sea surface temperature (SST) from ~25 °C to ~14 °C over the course of just a few hours and resulted in mass mortality of fishes31; (2) corals inhabiting a reef exposed to constant warm-water effluent from a nuclear power plant that have been able to not only survive, but thrive, in temperatures beyond their typical bleaching threshold (~29 °C)32, likely due to intermittent cold-water intrusion driven by internal waves induced upwelling33; and (3) the lunar timing of larval release of two brooding reef corals, which show temperature-related plasticity2,4. Regarding the latter, the peak reproductive timing shifted from around the full moon and spring tide in winter to around the first quarter moon and neap tide in summer; this may allow larvae released in the summer to avoid the impact of internal wave induced upwelling, which is strongest during the spring tide (full moon)4. In contrast, severe mass coral bleaching events occurred due to abnormally warm seawater temperatures during El Niño events in 1998, 2007, and 2016–1734,35.
Mechanisms for cold-water intrusions, including both local and remotely forced internal waves, have been explored in model-based studies25,26,36. However, the temperature variation in deep reefs, as well as the factors influencing the cold water intrusion in NW, has not been clearly addressed. A thorough assessment of in situ temperature data acquired at frequent (minutes-hours) intervals and assessed over long-term (weeks-years) timescales may help to shed light on these phenomena. Therefore, in situ bottom temperature measurements at depths of 5 and 30 m were recorded from 2007 to 2008. Complementary to these data, we also examined remote temperature data sets from the East Asian Seas Nowcast/Forecast System (EASNFS), developed by the US Naval Research Laboratory (NRL)36,37 to comprehensively describe the hydrographic field of NW. Our objectives were to (1) examine the temporal variation in temperature, with a particular emphasis on the minima, at shallow and deep coral reefs; (2) evaluate the possible roles of mesoscale eddies in influencing temperature patterns; (3) explore the possible sources of cold-water intrusions; and (4) examine the relationship between temperature and sea level in order to forecast temperature variation and extremes in NW.
## Results
The observed raw temperatures at the bottom of a seamount, S-rock (SR), and at the inlet (IL) of the Tai-Power third nuclear power plant (Fig. 1) from May 2007 to September 2008 are shown in Fig. 2a, and a finer-resolution comparison of a representative summer (July) and winter (January) months is shown in Fig. 2b,c. Seasonal variation is clear, whereby temperature was warmer in the summer (June to October) and cooler in the winter (November to May). Strong temperature fluctuations (>5 °C) were recorded in summer; temperatures varied between 18.2 and 30.8 °C at SR and 20.1 and 31 °C at IL. The majority of daily temperature minima coincided with the spring tides, as indicated in the Fig. 2a by the dates of the new and full moons. In summer, the daily magnitudes were 4–6 °C (5–9 °C) and 2–5 °C (3–8 °C) during neap (spring) tides for SR and IL, respectively (Fig. 2d,f). During winter, daily fluctuations only occurred during the spring tides, with daily magnitudes of 2–4 °C and 1–2 °C for SR and IL, respectively (Fig. 2e,g).
In the summer of 2007, both the SRmean and ILmean exceed 29 °C, the local coral bleaching threshold32, for ~5 days (day 214–218) and ~17 days (day 203–219) during late July and early August, respectively (Fig. 2a). The degree heating day (DHD)7 peaked at 10.31 °C-days on 7 August and at 4.25 °C-days on 9 August for IL and SR, respectively (Fig. 3). The DHD and degree heating week (DHW) from the United States National Oceanic and Atmospheric Administration (NOAA) Coral Reef Watch (CRW) satellite sensor data38 peaked at 17.89 °C-days on 4 August and at 4.34 °C-weeks during 8 August to 22 September, respectively. The SRmean and ILmean dropped and was lower than 29 °C due to the influence of three typhoons during 7 to 19 August (Fig. 2a).
The predominance of tidal fluctuations can be clearly seen in the corresponding temperature spectra (Fig. 4). Both records showed distinct energy peaks at the diurnal (~24 h [K1 and O1]), semidiurnal (~12.5 h [M2 and S2]), mixed (8 h), and higher tidal harmonics, as well as a smooth peak each fortnight related to spring-neap tides; energy peaks at SR were considerably larger than IL. Higher tidal harmonics might be caused by topographic effects since IL presented more peaks at higher frequencies than SR. The stronger signal at SR was likely related to larger temperature fluctuations since the magnitudes at SR were larger than IL. However, longer periods of motions cannot be well resolved because of data length limitations (i.e., periods depicting variation over longer-than-fortnightly scales are not evident).
The daily means of temperatures for SR (SRmean) and IL (ILmean) are shown in Fig. 2a, and both locations displayed similar seasonal patterns; SR varied between 22.1 and 29.3 °C and IL varied between 22.7 and 30.3 °C. SR was ~1–2 °C cooler during summer, but the two sites were approximately the same in winter. The annual temperature record showed large variations. Specifically, in summer 2007, the SRmean was ~26 °C in the middle of June (day 168), then increased to ~29 °C in early August (day 215), but decreased sharply to ~23 °C in the middle August (day 233). Over this same time period, the ILmean exceeded 29 °C in late June (day 171), and exceeded 30 °C in early July (day 188) and again in late July (day 205). In contrast, the 2008 summer averages (days 550–580) were considerably cooler; ILmean and SRmean were <29 °C and <28 °C, respectively.
The magnitudes of the daily temperature fluctuations were greater in summer than in winter, suggesting changes in the vertical temperature gradient of the surrounding water. Unfortunately, there were no concurrent temperature measurements in the open ocean. We therefore used model temperatures for the study period from the EASNFS reanalysis which assimilates all available satellite SST, SSHA (sea surface height anomaly), and in situ hydrographic observations. Figure 5 shows zonal temperature sections in the upper 250 m from EASNFS at 21.8°N, 120.3–121.6°E (marked in Fig. 1a) for the representative summer (July 2007) and winter (January 2008) months.
In the summer, model temperatures decreased from 30 °C at the surface to 14 °C at 250 m depth, showing strong stratification (Fig. 5a). Zonal horizontal temperature gradients were clearly observed below 30 m: temperatures were colder in the South China Sea (SCS), whereby, the zonal gradient increased with depth. The steep zonal slope of the isotherms is indicative of the Kuroshio current. In winter, the upper layer (<100 m) became well-mixed, and the zonal temperature gradient was weak (Fig. 5b). The Kuroshio current also migrated westward into the SCS. The water mass around NW was replaced by the Kuroshio current. Stratification was strong during summer and caused large temperature fluctuations in NW, whereas the stratification was too weak during winter to sustain large temperature fluctuations.
The lowest SR minimum temperature was 18.2 °C. Based on the model reanalysis, the cold water may have originated from depths shallower than 200 m (Fig. 5). We selected model temperatures at two depths to compare with our observations: 30 m, which is representative of the surface (mixed) layer, and 100 m, where the mean model daily temperature (~23.5 °C) was comparable to the mean observed daily temperature minimum (~23.0 °C) at SR. The chosen model grid was located at 21.902°N, 121.054°E, ~20 km east of NW at a depth of 1000 m (red dot in Fig. 1a). This location aimed to represent the surrounding conditions of the western North Pacific Ocean without interference from the coastal waters of Taiwan. Temperatures at the two depths (mT30 and mT100) were compared with the daily temperature maxima and minima at SR (SRmax and SRmin, Fig. 6). The daily maxima and minima at IL varied similarly but were warmer than SR. Correlation coefficients of SRmax vs. ILmax and SRmin vs. ILmin were 0.98 and 0.76, respectively.
The observed daily temperature maxima and minima were averaged into the same time interval as the model output (5-day mean). There were generally good agreements between SRmax and mT30 and between SRmin and mT100 (Fig. 6). The correlation coefficients for (1) SRmax and mT30 and (2) SRmin and mT100 were 0.92 and 0.56, respectively, with data from days 250–391 and 556–611 were discarded due to apparent differences; additionally, there were no data for days 392–425. This suggests that the model was able to capture background, low-frequency temperature fluctuations. SRmax and mT30 displayed seasonal variations: reaching ~30 °C in summer 2007, decreasing to ~25 °C in winter, then increasing to ~29 °C in summer 2008. The SRmax was generally colder by ~1 °C compared to mT30. This result indicates that, absent of cold-water intrusions, SR temperature varied with the surrounding ocean surface water.
Unlike SRmax, SRmin did not show seasonal variations (Fig. 6). Rather, SRmin was dominated by several large fluctuations with magnitudes of 3 to 5 °C in periods of weeks to months (e.g., the warm anomaly from the middle June to late August 2007 [days 165–240] noted earlier). A similar trend found between SRmin and mT100 indicated that the intruded cold water likely came from the open ocean at depths of ~100 m. SRmin, in addition, showed several sharp peaks (e.g., days 165, 180, 301, 316, 346 etc.) that were coincident with the full and new moons. The spring/neap modulation in SRmin likely reflects the large isotherm excursions in the Luzon Strait associated with strong internal waves. The internal wave component, however, was not included in the available EASNFS output.
Figure 7 shows the westward propagation of mesoscale eddies, as evidenced from the model dynamic height anomalies (referenced to 500 m) along 21.82°N. To relate NW temperature fluctuations to the approaching mesoscale eddies, mT100 data are displayed on the left in the same plot. The result shows that mT100 temperatures were warmer/colder when anticyclonic/cyclonic eddies appeared at 122°E. SRmin displayed similar behavior with mT100, as noted earlier (Fig. 6).
The residual (detided) sea level variations (resL), calculated from the observed sea level variations at IL, with diurnal (K1, O1) and semi-diurnal (M2, S2) tides removed, were caused by both local and remote effects; the latter was expected to be related to the open-ocean dynamic heights, and hence mT100. Since mT100 and SRmin were related, it was of interest to check if resL was correlated to SRmin and ILmin. Figure 8 shows the scatterplots of resL vs. SRmin and resL vs. ILmin. Both SRmin and ILmin were correlated to resL, with correlation coefficients of 0.65 and 0.58, respectively. This supports the hypothesis that the residual sea level variations in NW are mainly controlled by impinging mesoscale eddies.
## Discussion
Although temporal variation in seawater temperature in shallow (5–10 m) coral reefs has been well studied in NW4,13,25,26,31,32,33, this study is the first to examine the temporal variation in seawater temperature at a deep (30 m) coral reef in NW. The daily temperature minima showed large magnitude fluctuations (2–8 °C) over periods from weeks to months (Figs. 2, 6), and this week-to-month-scale variation at 30 m is in contrast to the scale and magnitude of temporal variation occurring at other deep coral reefs globally: e.g., Conch Reef, Florida Keys (45 m)39, Curacao, Netherlands Antilles (30 m)15, Discovery Bay, Jamaica (55 m)18, Moorea, French Polynesia (30 m)40, Heron Island, Australia (15–18 m)41, and Eilat in Red Sea (45 m)42,43.
The similarity between the time series of daily temperature minima at SR (SRmin) and the EASNFS temperature output (mT100, Fig. 6), as well as the correlation between the westward propagating cyclonic/anticyclonic eddies related to cold/warm anomalies of mT100 (Fig. 7), suggests that mesoscale eddies play an important role in shaping the temporal variation of daily temperature minima in deep coral reefs of NW. Mesoscale eddies that have occurred in East Taiwan and the Luzon Strait have been shown to influence the environmental conditions in NW44,45. Furthermore, the variation in daily temperature minima can be influenced by cold cyclonic eddies and warm anticyclonic eddies, respectively (Fig. 2a).
The large temperature fluctuations at both shallow and deep reefs in NW were likely a result of cold-water intrusions driven by both cold cyclonic eddies and internal wave-induced upwelling. During the mass coral bleaching events in the northwest Pacific in the summer of 20075,6,35, two major cold eddies affected NW; the first resulted in an SRmean <28 °C, and an ILmean <29 °C (both of which were lower than the local coral bleaching threshold of 29 °C [in situ seawater temperature maximum monthly mean (MMM) + 1 °C at IL])32 for ~10 days from early June to early July (Fig. 2a); the second cold eddy dropped the SRmean and ILmean to <29 °C during August and September. The high-frequency temperature oscillations, then, decreased temperatures below the MMM. Therefore, the low- and high-frequency cold-water intrusions may act as a buffer to reduce thermal stress, as such, could help mitigate coral bleaching, which is increasing in frequency and intensity as a result of climate change-induced ocean warming7,12,14,15,16,17.
In contrast to the generally beneficial effects of cold eddies, during the same El Niño event in the summer of 20075, a warm eddy caused both the SRmean and ILmean to exceed the local coral bleaching threshold of 29 °C32 for ~5 and ~17 days during late July and early August, respectively (Fig. 2a). The maximum DHD for IL and SR were 10.31 and 4.25 °C-days, and the corresponding peak in DHD and DHW from the NOAA CRW satellite sensor data were 17.89 °C-days and 4.34 °C-weeks, respectively (Fig. 3). DHW and DHD values > 4.0 °C-weeks and >4.0 °C-days, respectively, are known to induce coral bleaching elsewhere6,7,38. The combination of this warm eddy and the El Niño were coincidental with a severe mass coral bleaching event (up to 25% shallow-water corals bleached) observed that summer at NW34,35. In addition, mass coral bleaching events also occurred at nearby other reefs in southern Taiwan35, and Dongsha Atoll in the northern SCS5. This suggests that a warm eddy impinging in summer could negatively influence coral reefs by increasing the daily mean temperature by 1–2 °C, thereby diminishing the benefits from daily cold-water intrusions discussed in the previous paragraph. This is unfortunate given that mass coral bleaching events, linked with unusually warm summer seawater temperatures, are a global phenomenon and of increasing concern for the viability of coral reefs6,7,10,12,38.
Unsurprisingly, the temperature at our deep reef site (30 m) was different from that of our shallow reef site (5 m) in NW. The notion that temperature-induced bleaching is generally restricted to shallow depths urgently needs to be evaluated by pre- and post-bleaching surveys over broader depth ranges (i.e., encompassing the mesophotic zone, >30 m), coupled with long-term temperature monitoring over depth46,47. The large variation in temperature minima observed at NW shows the unique conditions experienced in this region and highlights southern Taiwan as a robust site for future research into the effect of large-scale oceanographic patterns on coral reefs48.
The sources of cold-water intrusions may originate from depths of ~100 m and were strongly affected by the westward propagating mesoscale eddies from the Pacific basin. The slow temperature variations in the surrounding region might be a result of the migration of Kuroshio current or impinging of mesoscale eddies (Fig. 6). The impinging mesoscale eddies in the western North Pacific, which could propagate for thousands of kilometers, have been studied for years; they can alter the thickness of the mixed layer49 or influence the transport of the Kuroshio current east of Taiwan28. The time scale relating to these eddies varies from weeks to months. Westward-moving eddies are common and may connect reef populations along the continental margin50.
The eddy impact was clearly revealed in our study by high correlations between the daily temperature minima and residual sea levels (Fig. 8). It might consequently be feasible to reconstruct historical temperature minimum in NW from the long-term coastal sea level records to trace the thermal effects on reef corals. The understanding and forecasting of temperature variation and extremes could help elucidate the causes and processes shaping biophysical phenomenon in coral reefs in the future.
We suggest that mesoscale eddies may, by modifying daily temperature variations over a sustained period, play an important role in coral reef ecology. A deeper understanding of the magnitude and time scale of temperature variations is necessary to comprehend the biophysical relationships governing coral reef ecosystems in NW and other locations, such as southern Great Barrier Reef24 and upper Florida Keys23, which are also influenced by mesoscale eddies. Mesoscale eddies play an important role in various physical, chemical, and biological processes such as facilitating mass transport, inducing nutrient flux, enhancing primary production, and promoting organism dispersal51,52,53. Pursuing more biophysical studies on the effects of mesoscale eddies may provide a better understanding of the influence of temperature extremes and variability on coral reefs.
## Methods
Observation. Seawater temperature and sea level were recorded simultaneously at IL, and temperature was recorded at SR (Fig. 1), from May 25, 2007 to September 8, 2008, with a temporal recording resolution of 10 min. Measurements were taken from bottom depths of 5 and 30 m for IL and SR, respectively. There were temperature gaps in February 2008 at SR due to logger malfunction. Temperature and depth were measured using HOBO® loggers (accuracy ± 0.2 °C and 1.5 cm, respectively, resolution 0.10 °C and 0.41 cm, respectively, response time <1 s, Onset Computer Co., Bourne, MA, USA), which were deployed and replaced every two months by divers. During replacement of the instruments, data from new and old loggers were overlapped for 10 minutes to account for potential systematic errors; mean sea level variation data were removed. The differences between overlapping temperatures and pressure readings were <0.2 °C and <0.05 decibar (<5 cm), respectively.
Time series of raw temperature data, as well as daily mean, daily maximum, and daily minimum temperatures, were used to analyze temporal variation across hourly, daily, weekly, monthly, and seasonal scales. DHD, summed positive deviations of temperatures exceeding 1 °C above the climatology MMM SST and integrated over past 12 days, was calculated to quantify heat accumulation as follows7:
$${\rm{DHD}}=\frac{{\sum }_{{\rm{t}}{\rm{-}}12}^{{\rm{t}}}\,\hat{{\rm{T}}}({\rm{t}})}{{\rm{N}}},$$
$$\hat{{\rm{T}}}({\rm{t}})=\mathop{\sum }\limits_{{\rm{i}}-{\rm{N}}}^{{\rm{i}}}\Delta {\rm{T}}({\rm{i}}),\Delta {\rm{T}}({\rm{i}})=\{\begin{array}{l}{\rm{T}}({\rm{i}})-{\rm{MMM}},{\rm{if}}\,\Delta {\rm{T}}({\rm{i}})\ge 1\,{}^{\circ }\,{\rm{C}}\\ 0,{\rm{if}}\,\Delta {\rm{T}}({\rm{i}}) < 1\,{}^{\circ }\,{\rm{C}}\end{array},{\rm{i}}=1 \sim {\rm{N}}$$
where T(i) is observed temperature; N = 144 for the number of samples over one day with a 10-min data logging interval; N = 1 for daily SST satellite data; MMM = 28.96 °C during 1985–2012 around Nanwan Bay (21.925°N, 120.775°E; based on daily SST satellite observations from https://coralreefwatch.noaa.gov/product/5km/index_5km_composite.php)38; $$\hat{{\rm{T}}}({\rm{t}})$$ = sum of ΔT(i) over a moving window of 1-day length; and DHD is the sum of $$\hat{{\rm{T}}}({\rm{t}})$$ over a 12-day moving window.
Spectral analysis was used to assess the raw temperature time series data at both sites using the Matlab program ‘pwelch.m’ with a 95% confidence interval applied (ver. R2016). Data lengths used for SR and IL were 254 days (data collected before the logger malfunction) and 473 days (whole record shown in Fig. 2a), respectively. Data sections from both sites overlapped by ~50% and were windowed (43 days) with a Hamming function before spectra for each site were calculated. The degree of freedom was 11.8 and 22 (average = 16.9) for SR and IL, respectively. The Nyquist frequency was 72 cpd. The resolved frequency ranged from 0.034 cpd up to 72 cpd. Due to differences in data length, motions with periods longer than half a month were not well resolved. The residual (detided) sea level variations (resL) were calculated from the observed sea level variations at IL with diurnal (K1, O1) and semi-diurnal (M2, S2) tides removed. The relationship between residual sea level and daily temperature minimum was examined via regression.
Model reanalysis output. EASNFS is an application produced by the U.S. Naval Research Laboratory’s Ocean Nowcast/Forecast System36 that was adapted from the Princeton Ocean Model (POM) with modifications to accommodate for extensive data assimilation. The model domain covers the entire East Asian Marginal Seas and part of the western Pacific Ocean, ranging from 17.3°S to 52.2°N and from 99.2°E to 158.2°E. The model’s horizontal resolution is ~1/12° (~9 km at 22°N). There are 41 sigma-z levels, with denser levels in the upper water column to resolve data for the upper ocean. The available model output is presented in the form of a 5-day averaged three-dimensional field. EASNFS was based on surface forcing data from the Navy Operational Global Atmospheric Prediction System (NOGAPS)54 and assimilated satellite altimeter data and multi-channel SST (MCSST). A detailed description of the forecasting application and data assimilation can be found in Ko and Wang (2014)55. EASNFS has been applied to a wide array of studies, for example, to assess anomalous upwelling in NW36, and to examine thermal structures in the SCS56. The datasets generated during and/or analysed during the current study are available in the figshare repository https://doi.org/10.6084/m9.figshare.1004737757.
|
2022-12-05 16:10:53
|
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|
https://girlsangle.wordpress.com/2017/10/31/girls-angle-bulletin-volume-11-number-1/
|
## Girls’ Angle Bulletin, Volume 11, Number 1
We begin the second decade of the Bulletin with a fascinating image by Arnaud Chéritat, CNRS/Institut de Mathématiques de Toulouse, called Two mating polynomial Julia sets. For more about these images, visit his website. The two images by him (on the cover and inside) were included at the urging of Sarah Koch, this issue’s interview subject. Prof. Koch is Associate Professor of Mathematics at the University of Michigan. She studies complex analysis, Teichmüller theory, and complex dynamics. In her interview, she describes a game you can play called the “chaos game”. If you play the chaos game long enough, you will create fractals. We include some images of such fractals right after the interview.
Recently, Girls’ Angle member π has been learning about integrals and decided to set herself the task of computing the center of mass of a semicircle of uniform mass density. One question led to another, and before we knew it, we had stumbled upon Euler’s formula
$\displaystyle \frac{\sin x}{x} = \prod_{k=1}^{\infty} \cos(x/2^k)$.
We retrace our journey in Pac-Man Meets Euler.
In Volume 10, Number 3 of this Bulletin, Addie Summer explained how she found the quadratic formula. As it turns out, Lightning Factorial also figured out the quadratic formula without having to be taught it. She explains her method in The Quadratic Formula, Revisited.
In Anna’s Math Journal, Anna succeeds in finding a way to show that the number of special tilings of a rectangle are counted by the Catalan numbers without using generating functions. This represents the culmination of 6 installments’ investigation.
Next comes a special Math Buffet. We asked a number of mathematicians to contribute an excerpt from their scratch work to give us a window on what it looks like when they are in the act of creating mathematics. A huge and heartfelt Thank You to Timothy Chow, Brendan Creutz, Danijela Damjanović, Laura DeMarco, Ellen Eischen, Elisenda Grigsby, Kathryn Mann, Elizabeth Meckes, Maria Monks, Radmila Sazdanović, Marjorie Senechal, Bianca Viray, Fan Wei, Kirsten Wickelgren, Lauren Williams, and Helen Wong for allowing us a look into their personal process of doing math. Special thanks to Ashley Wang for doing the layout.
Emily and Jasmine are getting very close to resolving their long-standing search for nice triangles. In this installment, they succeed in computing the constant terms of all the minimum polynomials of cosines of rational multiples of π. By Vieta’s formulas, this is equivalent to computing
$\displaystyle \prod_{(k,n)=1, 0 < k \le n/2} \cos(2\pi\frac{k}{n})$
for all $n > 1$.
We conclude with some notes from the club.
We hope you enjoy it!
Finally, a reminder: when you subscribe to the Girls’ Angle Bulletin, you’re not just getting a subscription to a magazine. You are also gaining access to the Girls’ Angle mentors. We urge all subscribers and members to write us with your math questions or anything else in the Bulletin or having to do with mathematics in general. We will respond. We want you to get active and do mathematics. Parts of the Bulletin are written to induce you to wonder and respond with more questions. Don’t let those questions fade away and become forgotten. Send them to us!
We continue to encourage people to subscribe to our print version, so we have removed some content from the electronic version. Subscriptions are a great way to support Girls’ Angle while getting something concrete back in return. We hope you subscribe!
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2018-01-16 09:26:53
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http://pygeno.iric.ca/importation.html
|
# Importation¶
pyGeno’s database is populated by importing tar.gz compressed archives called datawraps. An importation is a one time step and once a datawrap has been imported it can be discarded with no concequences to the database.
Here’s how you import a reference genome datawrap:
from pyGeno.importation.Genomes import *
importGenome("my_genome_datawrap.tar.gz")
And a SNP set datawrap:
from pyGeno.importation.SNPs import *
importSNPs("my_snp_datawrap.tar.gz")
pyGeno comes with a few datawraps that you can quickly import using the Bootstraping module.
You can find a list of datawraps to import here: Datawraps
You can also easily create your own by simply putting a bunch of URLs into a manifest.ini file and compressing int into a tar.gz archive (as explained below or on the Wiki).
## Genomes¶
importation.Genomes.backUpDB()[source]
backup the current database version. automatically called by importGenome(). Returns the filename of the backup
importation.Genomes.deleteGenome(species, name)[source]
Removes a genome from the database
importation.Genomes.importGenome(packageFile, batchSize=50, verbose=0)[source]
Import a pyGeno genome package. A genome packages is folder or a tar.gz ball that contains at it’s root:
• gziped fasta files for all chromosomes, or URLs from where them must be downloaded
• gziped GTF gene_set file from Ensembl, or an URL from where it must be downloaded
• a manifest.ini file such as:
[package_infos]
description = Test package. This package installs only chromosome Y of mus musculus
maintainer = Tariq Daouda
maintainer_contact = tariq.daouda [at] umontreal
version = GRCm38.73
[genome]
species = Mus_musculus
name = GRCm38_test
source = http://useast.ensembl.org/info/data/ftp/index.html
[chromosome_files]
Y = Mus_musculus.GRCm38.73.dna.chromosome.Y.fa.gz / or an url such as ftp://... or http://
[gene_set]
gtf = Mus_musculus.GRCm38.73_Y-only.gtf.gz / or an url such as ftp://... or http://
A rollback is performed if an exception is caught during importation
batchSize sets the number of genes to parse before performing a database save. PCs with little ram like small values, while those endowed with more memory may perform faster with higher ones.
Verbose must be an int [0, 4] for various levels of verbosity
## Polymorphisms (SNPs and Indels)¶
importation.SNPs.deleteSNPs(setName)[source]
deletes a set of polymorphisms
importation.SNPs.importSNPs(packageFile)[source]
The big wrapper, this function should detect the SNP type by the package manifest and then launch the corresponding function. Here’s an example of a SNP manifest file for Casava SNPs:
[package_infos]
description = Casava SNPs for testing purposes
maintainer = Tariq Daouda
maintainer_contact = tariq.daouda [at] umontreal
version = 1
[set_infos]
species = human
name = dummySRY
type = Agnostic
source = my place at the IRIC
[snps]
filename = snps.txt # as with genomes you can either include de file at the root of the package or specify an URL from where it must be downloaded
|
2018-01-18 05:56:25
|
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|
https://manual.q-chem.com/5.4/Ch7.S11.SS11.html
|
(June 30, 2021)
For an ADC calculation it is important to ensure that there are sufficient resources available for the necessary integral calculations and transformations. These resources are controlled using the $rem variables MEM_STATIC and MEM_TOTAL. The memory used by ADC is currently 95% of the difference MEM_TOTAL $-$ MEM_STATIC. An ADC calculation is requested by setting the$rem variable METHOD to the respective ADC variant. Furthermore, the number of excited states to be calculated has to be specified using one of the $rem variables EE_STATES, EE_SINGLETS or EE_TRIPLETS. The former variable should be used for open-shell or unrestricted closed-shell calculations, while the latter two variables are intended for restricted closed-shell calculations. Even though not recommended, it is possible to use EE_STATES in a restricted calculation which translates into EE_SINGLETS, if neither EE_SINGLETS nor EE_TRIPLETS is set. Similarly, the use EE_SINGLETS in an unrestricted calculation will translate into EE_STATES, if the latter is not set as well. For IP- and EA-ADC calculations, the IP_STATES, EOM_IP_ALPHA, EOM_IP_BETA, EA_STATES, EOM_EA_ALPHA and EOM_EA_BETA are available to control the number and type of ionized or electron-attached states to calculate. IP_STATES and EA_STATES should be used in case of restricted calculations, while the EOM_[IP/EA]_[ALPHA/BETA] keywords control the number of $\alpha$- and $\beta$-ionized and -electron-attached states to calculate in case of unrestricted or open-shell calculations. All$rem variables to set the number of excited, ionized or electron-attached states accept either an integer number or a vector of integer numbers. A single number specifies that the same number of excited states are calculated for every irreducible representation the point group of the molecular system possesses (molecules without symmetry are treated as $C_{1}$ symmetric). In contrast, a vector of numbers determines the number of states for each irreducible representation explicitly. Thus, the length of the vector always has to match the number of irreducible representations. Hereby, the excited states are labeled according to the irreducible representation of the electronic transition which might be different from the irreducible representation of the excited state wave function. Users can choose to calculate any molecule as $C_{1}$ symmetric by setting CC_SYMMETRY = FALSE.
METHOD
Controls the order in perturbation theory of ADC.
TYPE:
STRING
DEFAULT:
None
OPTIONS:
RECOMMENDATION:
None
EE_STATES
Controls the number of excited states to calculate.
TYPE:
INTEGER/ARRAY
DEFAULT:
0 Do not perform an ADC calculation
OPTIONS:
$n>0$ Number of states to calculate for each irrep or $[n_{1},n_{2},...]$ Compute $n_{1}$ states for the first irrep, $n_{2}$ states for the second irrep, …
RECOMMENDATION:
Use this variable to define the number of excited states in case of unrestricted or open-shell calculations. In restricted calculations it can also be used, if neither EE_SINGLETS nor EE_TRIPLETS is given. Then, it has the same effect as setting EE_SINGLETS.
EE_SINGLETS
Controls the number of singlet excited states to calculate.
TYPE:
INTEGER/ARRAY
DEFAULT:
0 Do not perform an ADC calculation of singlet excited states
OPTIONS:
$n>0$ Number of singlet states to calculate for each irrep or $[n_{1},n_{2},...]$ Compute $n_{1}$ states for the first irrep, $n_{2}$ states for the second irrep, …
RECOMMENDATION:
Use this variable to define the number of excited states in case of restricted calculations of singlet states. In unrestricted calculations it can also be used, if EE_STATES not set. Then, it has the same effect as setting EE_STATES.
EE_TRIPLETS
Controls the number of triplet excited states to calculate.
TYPE:
INTEGER/INTEGER ARRAY
DEFAULT:
0 Do not perform an ADC calculation of triplet excited states
OPTIONS:
$n>0$ Number of triplet states to calculate for each irrep or $[n_{1},n_{2},...]$ Compute $n_{1}$ states for the first irrep, $n_{2}$ states for the second irrep, …
RECOMMENDATION:
Use this variable to define the number of excited states in case of restricted calculations of triplet states.
IP_STATES
Controls the number of ionized states to calculate.
TYPE:
INTEGER/INTEGER ARRAY
DEFAULT:
0 Do not perform an IP-ADC calculation
OPTIONS:
$n>0$ Number of states to calculate for each irrep or $[n_{1},n_{2},...]$ Compute $n_{1}$ states for the first irrep, $n_{2}$ states for the second irrep, …
RECOMMENDATION:
Use this variable to define the number of ionized states in case of restricted calculations.
EOM_IP_ALPHA
Controls the number of $\alpha$-ionized states to calculate.
TYPE:
INTEGER/INTEGER ARRAY
DEFAULT:
0 Do not compute $\alpha$-ionized states
OPTIONS:
$n>0$ Number of $\alpha$-ionized states to calculate for each irrep or $[n_{1},n_{2},...]$ Compute $n_{1}$ $\alpha$-ionized states for the first irrep, $n_{2}$ $\alpha$-ionized states for the second irrep, …
RECOMMENDATION:
Use this variable to define the number of $\alpha$-ionized states in case of unrestricted or open-shell calculations.
EOM_IP_BETA
Controls the number of $\beta$-ionized states to calculate.
TYPE:
INTEGER/INTEGER ARRAY
DEFAULT:
0 Do not compute $\beta$-ionized states
OPTIONS:
$n>0$ Number of $\beta$-ionized states to calculate for each irrep or $[n_{1},n_{2},...]$ Compute $n_{1}$ $\beta$-ionized states for the first irrep, $n_{2}$ $\beta$-ionized states for the second irrep, …
RECOMMENDATION:
Use this variable to define the number of $\beta$-ionized states in case of unrestricted or open-shell calculations.
EA_STATES
Controls the number of electron-attached states to calculate.
TYPE:
INTEGER/INTEGER ARRAY
DEFAULT:
0 Do not perform an EA-ADC calculation
OPTIONS:
$n>0$ Number of states to calculate for each irrep or $[n_{1},n_{2},...]$ Compute $n_{1}$ states for the first irrep, $n_{2}$ states for the second irrep, …
RECOMMENDATION:
Use this variable to define the number of electron-attached states in case of restricted calculations.
EOM_EA_ALPHA
Controls the number of $\alpha$-electron-attached states to calculate.
TYPE:
INTEGER/INTEGER ARRAY
DEFAULT:
0 Do not compute $\alpha$-electron-attached states
OPTIONS:
$n>0$ Number of $\alpha$-electron-attached states to calculate for each irrep or $[n_{1},n_{2},...]$ Compute $n_{1}$ $\alpha$-electron-attached states for the first irrep, $n_{2}$ $\alpha$-electron-attached states for the second irrep, …
RECOMMENDATION:
Use this variable to define the number of $\alpha$-electron-attached states in case of unrestricted or open-shell calculations.
EOM_EA_BETA
Controls the number of $\beta$-electron-attached states to calculate.
TYPE:
INTEGER/INTEGER ARRAY
DEFAULT:
0 Do not compute $\beta$-electron-attached states
OPTIONS:
$n>0$ Number of $\beta$-electron-attached states to calculate for each irrep or $[n_{1},n_{2},...]$ Compute $n_{1}$ $\beta$-electron-attached states for the first irrep, $n_{2}$ $\beta$-electron-attached states for the second irrep, …
RECOMMENDATION:
Use this variable to define the number of $\beta$-electron-attached states in case of unrestricted or open-shell calculations.
CC_SYMMETRY
Activates point-group symmetry in the ADC calculation.
TYPE:
LOGICAL
DEFAULT:
TRUE If the system possesses any point-group symmetry.
OPTIONS:
TRUE Employ point-group symmetry FALSE Do not use point-group symmetry
RECOMMENDATION:
None
Controls the order of the ground state density used for the computation of third-order ADC matrix elements (non-CVS methods only).
TYPE:
INTEGER
DEFAULT:
2 Use strict third-order ADC(3) schemes.
OPTIONS:
3 Use a third-order ground state density computed from the IP-ADC(3) effective transition moments and the corresponding fourth order static self-energy according to the $\Sigma(4)$ scheme 4 Use an improved third-order ground state density and the corresponding improved fourth-order static self-energy computed according to the self-consistent $\Sigma(4+)$ procedure
RECOMMENDATION:
In case of IP-ADC(3) calculations, employing the $\Sigma(4+)$ scheme provides more accurate ionization potentials and ionized state dipole moments.
When setting ADC_DENSITY_ORDER = 4, this keyword controls the maximum number of DIIS iterations carried out in the $\Sigma(4+)$ procedure.
TYPE:
INTEGER
DEFAULT:
1000
OPTIONS:
$n$ User-defined integer.
RECOMMENDATION:
Use the default value.
For third-order ADC methods, this keyword controls if some large intermediate tensor contractions should be carried out in advance and the result saved in memory for later use or if these quantities should be evaluated directly whenever they are encountered.
TYPE:
LOGICAL
DEFAULT:
FALSE
OPTIONS:
TRUE Directly evaluate some $N^{6}$-scaling tensor contractions. This will reduce the memory requirement by $\sim$10 %. FALSE Precompute all possible $N^{6}$-scaling intermediates. This will speed up ADC(3) calculations considerably (by a factor of $\sim$3 in case of ADC(3) for $N$-electron excitations and somewhat less for IP- and EA-ADC(3)).
RECOMMENDATION:
Use the default value unless memory is the bottleneck.
Controls how second-order ground state contributions are treated in the calculation of second- and third-order IP- and EA-ADC state properties using the second-order ISR formalism.
TYPE:
LOGICAL
DEFAULT:
FALSE
OPTIONS:
TRUE Scale the second-order part of the ground state contribution to one-electron properties of ionized/electron-attached states by the one-hole/one-particle character of the respective states as implied by the strict ISR derivation. FALSE Use the full second-order ground state contribution for each ionized/electron-attached state property.
RECOMMENDATION:
Use the default value. Both options are, however, valid second-order treatments of ionized/electron-attached state properties and should yield very similar results for states with predominant one-hole/one-particle chaaracter.
Controls if Dyson orbitals are output in case of IP- and EA-ADC calculations. This keyword only takes effect when used together with STATE_ANALYSIS = TRUE. See Section. 10.2.6 for further details.
TYPE:
LOGICAL
DEFAULT:
FALSE
OPTIONS:
TRUE Output Dyson orbitals as cube files. FALSE Do not output Dyson orbitals.
RECOMMENDATION:
Set to TRUE if visualization of ionization/electron-attachment processes is desired.
Controls the type of CAP/ADC calculation to be performed.
TYPE:
INTEGER
DEFAULT:
0 Do not perform a CAP/ADC calculation.
OPTIONS:
1 Perform a subspace-projected CAP/ADC calculation.
RECOMMENDATION:
Set to 1 for the computation of CAP/ADC subspace projections.
CAP_X
For ADC methods, in combination with a smoothed Voronoi-CAP (CAP_TYPE = 2) or a spherical CAP (CAP_TYPE = 0), this keyword controls the lower limit for a series of CAP onsets, where the upper limit is given by CAP_X_END. The parameter value in a.u. is obtained by multiplying the given integer by $10^{-3}$. In this case, the onset value defines the region around the molecule with zero CAP strength. In combination with a cuboid CAP (CAP_TYPE = 1) or in general for other electronic structure methods (see 7.10.8 for further details), this keyword controls the CAP onset in $x$ direction.
TYPE:
INTEGER
DEFAULT:
0
OPTIONS:
$n>0$ User-defined integer.
RECOMMENDATION:
Usually, values of 2000 to 4000 (corresponding to onset values between 2.0 and 4.0 a.u.) give reasonable results.
CAP_X_STEP
Controls the step size for a series of CAP onsets between CAP_X and CAP_X_END. The parameter value in a.u. is obtained by multiplying the given integer by $10^{-3}$. Currently only used in ADC methods.
TYPE:
INTEGER
DEFAULT:
500 corresponding to 0.5 a.u.
OPTIONS:
$n>0$ User-defined integer.
RECOMMENDATION:
None.
CAP_X_END
Controls the upper onset limit for a series of CAP onsets, where the lower limit is given by CAP_X. The parameter value in a.u. is obtained by multiplying the given integer by $10^{-3}$. Currently only used in ADC methods.
TYPE:
INTEGER
DEFAULT:
CAP_X Do not compute a series of CAP onsets but only use a single CAP with an onset value of CAP_X.
OPTIONS:
$n>\text{\mbox{{\small CAP\_X}}}$ User-defined integer.
RECOMMENDATION:
Use this keyword if CAP onset series are desired.
Controls the calculation of excited, ionized or electron-attached state properties (currently only dipole moments and $\hat{r}^{2}$ expectation values).
TYPE:
LOGICAL
DEFAULT:
FALSE
OPTIONS:
TRUE Calculate excited, ionized or electron-attached state properties. FALSE Do not compute state properties.
RECOMMENDATION:
Set to TRUE, if properties are required.
Controls the calculation of transition properties between excited, ionized or electron-attached states (currently only transition dipole moments and oscillator strengths). For ADC for $N$-electron excitations, this keyword also controls the computation of two-photon absorption cross-sections of excited states using the sum-over-states expression.
TYPE:
LOGICAL
DEFAULT:
FALSE
OPTIONS:
TRUE Calculate state-to-state transition properties. FALSE Do not compute transition properties between excited, ionized or electron-attached states.
RECOMMENDATION:
Controls the calculation of two-photon absorption cross-sections of excited states using matrix inversion techniques.
TYPE:
LOGICAL
DEFAULT:
FALSE
OPTIONS:
TRUE Calculate two-photon absorption cross-sections. FALSE Do not compute two-photon absorption cross-sections.
RECOMMENDATION:
Set to TRUE, if to obtain two-photon absorption cross-sections.
STATE_ANALYSIS
Controls the analysis and export of excited, ionized or electron-attached state densities and orbitals (see 10.2.6 for details).
TYPE:
LOGICAL
DEFAULT:
FALSE
OPTIONS:
TRUE Perform excited state analyses. FALSE No excited state analyses or export will be performed.
RECOMMENDATION:
Set to TRUE, if detailed analysis of the excited, ionized or electron-attached states is required or if density or orbital plots are needed.
Set the spin-opposite scaling parameter $c_{T}$ for an SOS-ADC(2) calculation. The parameter value is obtained by multiplying the given integer by $10^{-3}$.
TYPE:
INTEGER
DEFAULT:
1300 Optimized value $c_{T}=1.3$.
OPTIONS:
$n$ Corresponding to $n\cdot 10^{-3}$
RECOMMENDATION:
Use the default.
Set the spin-opposite scaling parameter $c_{c}$ for the ADC(2) calculation. The parameter value is obtained by multiplying the given integer by $10^{-3}$.
TYPE:
INTEGER
DEFAULT:
1170 Optimized value $c_{c}=1.17$ for ADC(2)-s or 1000 $c_{c}=1.0$ for ADC(2)-x
OPTIONS:
$n$ Corresponding to $n\cdot 10^{-3}$
RECOMMENDATION:
Use the default.
Set the spin-opposite scaling parameter $c_{x}$ for the ADC(2)-x calculation. The parameter value is obtained by multiplying the given integer by $10^{-3}$.
TYPE:
INTEGER
DEFAULT:
1300 Optimized value $c_{x}=0.9$ for ADC(2)-x.
OPTIONS:
$n$ Corresponding to $n\cdot 10^{-3}$
RECOMMENDATION:
Use the default.
Controls the number of excited state guess vectors which are single excitations, one-hole ionizations and one-particle electron-attachments in case of ADC, IP-ADC and EA-ADC, respectively. If the number of requested excited states exceeds the total number of guess vectors (singles and doubles), this parameter is automatically adjusted, so that the number of guess vectors matches the number of requested excited states.
TYPE:
INTEGER
DEFAULT:
Equals to the number of excited states requested.
OPTIONS:
$n$ User-defined integer.
RECOMMENDATION:
Increase if there are convergence problems.
Controls the number of excited state guess vectors which are double excitations, two-hole-one-particle ionizations and one-hole-two-particle electron-attachments in case of ADC, IP-ADC and EA-ADC, respectively.
TYPE:
INTEGER
DEFAULT:
0
OPTIONS:
$n$ User-defined integer.
RECOMMENDATION:
Activates the use of the DIIS algorithm for the calculation of ADC(2) excited states.
TYPE:
LOGICAL
DEFAULT:
FALSE
OPTIONS:
TRUE Use DIIS algorithm. FALSE Do diagonalization using Davidson algorithm.
RECOMMENDATION:
None.
Controls the iteration step at which DIIS is turned on.
TYPE:
INTEGER
DEFAULT:
1
OPTIONS:
$n$ User-defined integer.
RECOMMENDATION:
Set to a large number to switch off DIIS steps.
Controls the size of the DIIS subspace.
TYPE:
INTEGER
DEFAULT:
7
OPTIONS:
$n$ User-defined integer
RECOMMENDATION:
None
Controls the maximum number of DIIS iterations.
TYPE:
INTEGER
DEFAULT:
50
OPTIONS:
$n$ User-defined integer.
RECOMMENDATION:
Increase in case of slow convergence.
Controls the convergence criterion for the excited state energy during DIIS.
TYPE:
INTEGER
DEFAULT:
6 Corresponding to $10^{-6}$
OPTIONS:
$n$ Corresponding to $10^{-n}$
RECOMMENDATION:
None
Convergence criterion for the residual vector norm of the excited state during DIIS.
TYPE:
INTEGER
DEFAULT:
6 Corresponding to $10^{-6}$
OPTIONS:
$n$ Corresponding to $10^{-n}$
RECOMMENDATION:
None
Controls the maximum subspace size for the Davidson procedure.
TYPE:
INTEGER
DEFAULT:
$5\times$ the number of excited states to be calculated.
OPTIONS:
$n$ User-defined integer.
RECOMMENDATION:
Should be at least 2–4$\times$ the number of excited states to calculate. The larger the value the more disk space is required.
Controls the maximum number of iterations of the Davidson procedure.
TYPE:
INTEGER
DEFAULT:
60
OPTIONS:
$n$ Number of iterations
RECOMMENDATION:
Use the default unless convergence problems are encountered.
Controls the convergence criterion of the Davidson procedure.
TYPE:
INTEGER
DEFAULT:
$6$ Corresponding to $10^{-6}$
OPTIONS:
$n\leq 12$ Corresponding to $10^{-n}$.
RECOMMENDATION:
Use the default unless higher accuracy is required or convergence problems are encountered.
Controls the threshold for the norm of expansion vectors to be added during the Davidson procedure.
TYPE:
INTEGER
DEFAULT:
Twice the value of ADC_DAVIDSON_CONV, but at maximum $10^{-14}$.
OPTIONS:
$n\leq 14$ Corresponding to $10^{-n}$
RECOMMENDATION:
Use the default unless convergence problems are encountered. The threshold value $10^{-n}$ should always be smaller than the convergence criterion ADC_DAVIDSON_CONV.
Controls the amount of printing during an ADC calculation.
TYPE:
INTEGER
DEFAULT:
1 Basic status information and results are printed.
OPTIONS:
0 Quiet: almost only results are printed. 1 Normal: basic status information and results are printed. 2 Debug: more status information, extended information on timings.
RECOMMENDATION:
Use the default.
Activates the use of the CVS approximation for the calculation of CVS-ADC core-excited states.
TYPE:
LOGICAL
DEFAULT:
FALSE
OPTIONS:
TRUE Activates the CVS approximation. FALSE Do not compute core-excited states using the CVS approximation.
RECOMMENDATION:
Set to TRUE, if to obtain core-excited states for the simulation of X-ray absorption spectra. In the case of TRUE, the $rem variable CC_REST_OCC has to be defined as well. CC_REST_OCC Sets the number of restricted occupied orbitals including active core occupied orbitals. TYPE: INTEGER DEFAULT: 0 OPTIONS: $n$ Restrict $n$ energetically lowest occupied orbitals to correspond to the active core space. RECOMMENDATION: Example: cytosine with the molecular formula C${}_{4}$H${}_{5}$N${}_{3}$O includes one oxygen atom. To calculate O 1s core-excited states, $n$ has to be set to 1, because the 1s orbital of oxygen is the energetically lowest. To obtain the N 1s core excitations, the integer $n$ has to be set to 4, because the 1s orbital of the oxygen atom is included as well, since it is energetically below the three 1s orbitals of the nitrogen atoms. Accordingly, to simulate the C 1s spectrum of cytosine, $n$ must be set to 8. SF_STATES Controls the number of excited spin-flip states to calculate. TYPE: INTEGER DEFAULT: 0 Do not perform a SF-ADC calculation OPTIONS: $n>0$ Number of states to calculate for each irrep or $[n_{1},n_{2},...]$ Compute $n_{1}$ states for the first irrep, $n_{2}$ states for the second irrep, … RECOMMENDATION: Use this variable to define the number of excited states in the case of a spin-flip calculation. SF-ADC is available for ADC(2)-s, ADC(2)-x and ADC(3). Keywords for SS-PCM control in$pcm:
EQSOLV
Main switch of the self-consistent SS-PCM procedure.
INPUT SECTION: $pcm TYPE: INTEGER DEFAULT: 0 OPTIONS: 0 No self-consistent SS-PCM. 1 Single SS-PCM calculation (SCF+ADC) with the solvent field found on disk. $n>$1 Do a maximum of $n$ automatic solvent-field iterations. RECOMMENDATION: We recommend to use 15 steps max. Typical convergence is 3-5 steps. In difficult cases 6-12. If the solvent-field iteration do not converge in 15 steps, something is wrong. Also make sure that a solvent field has been stored on disk by a previous job. EQSTATE Specifies the state for which the solvent field is to be optimized. INPUT SECTION:$pcm
TYPE:
INTEGER
DEFAULT:
0
OPTIONS:
0 MP2 ground state (for PTED approach) 1 energetically lowest excited state 2 2nd lowest excited state
RECOMMENDATION:
Given that only one class of excited states is calculated, the state will be selected according to its energetic position shown in the “Exited-State Summary” of the output file. A maximum of 99 states is stored and can be selected.
EQS_CONV
Controls the convergence of the solvent-field iterations by setting the convergence criteria (a mixture of SCF energy and charge-vector). SCF energy criterion computes as $10^{-\rm value}$ $E_{h}$.
INPUT SECTION: $pcm TYPE: INTEGER DEFAULT: SCF_CONVERGENCE$-4=4$ OPTIONS: 3 May be sufficient for emission energies 4 Assured converged total energies (2.7 meV) 5 Really tight RECOMMENDATION: Use the default. EQS_REF Allows to specify which state is to be treated as the reference state in the ADC part of the calculation. Does in contrast to EQSTATE not affect which solvent field is loaded in the SCF step. Only has to be used when singlets are computed in the solvent field of a triplet reference. Note that (converged) singlets states are always counted before triplets, and thus to select $T_{1}$ in a calculation with EE_SINGLETS = 2 this has to be set to 3. INPUT SECTION:$pcm
TYPE:
INTEGER
DEFAULT:
Same as EQSTATE
OPTIONS:
1 First excited state 2 Second excited state
RECOMMENDATION:
Only needed when computing singlet states in the solvent field of a triplet reference.
|
2021-09-27 23:07:29
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|
https://www.dcode.fr/sudoku-solver
|
Search for a tool
Sudoku Solver
Tool/Solver to resolve sudoku/wordoku grids (directly or step by step). The aim of the sudoku game is to fill the rows and columns of a 9x9 grid with each digit only once.
Results
Sudoku Solver -
Tag(s) : Number Games
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# Sudoku Solver
## Solve a sudoku grid
Resolution Compute all solutions Step by Step Solution
Tool/Solver to resolve sudoku/wordoku grids (directly or step by step). The aim of the sudoku game is to fill the rows and columns of a 9x9 grid with each digit only once.
### How to fill the Sudoku grid?
Make a copy/paste or type directly in cells. Letters (Wordoku/alphadoku) and digits are accepted.
Example: Copy the Sudoku content in the first cell (top left) 97 1 5 5 9 2 18 4 8 7 26 92 3 6 2 9 19 4572 to get :
9 7 1 5 5 9 2 1 8 4 8 7 2 6 9 2 3 6 2 9 1 9 4 5 7 2
### How does the step by step works?
Software solves the Sudoku like an human and display each step of its progress to understand.
Sometimes the reasoning stops at a step where no logical deduction can deduce at 100% the value of a box (several possible values). The solver performs a random pick among these possible values and continues, if an inconsistency occurs (the sudoku turns to have no solution) then it goes back to the step of the random pick and choose another value. To maximize the chances, choose a number which, if it is positioned in the cell, will allow the maximum of deduction in the continuation of the sudoku.
If the program indicates that there is only one possible value, it means that no other value is acceptable in the box.
### How to test if a sudoku has a unique solution?
dCode calculates all the solutions for the sudoku, not only the first one. To check a homemade sudoku, the solver can confirm that there is only one solution.
### When Sudoku have been invented?
The first Sudoku versions are from 1979
### How many distinct sudokus exist?
A line can consist of $9!$ (Factorial of 9) different ways, but the whole sudoku has a number of possibilities much less than $9!^9$, because some permutations can lead to identical grids. The total number of grids would be $9! \times 72^2 \times 27 \times 27 \times 704267971 = 6670903752021072936960$ combinations.
### Does a rectangular sudoku or non square sudoku exists?
By keeping the sudoku NxN rules that require the N characters to be used on each row and column, then it is impossible to respect them if the sudoku is not square.
Some variants of the square sudoku, however, use non-square inner blocks (see sudoku 6x6, sudoku 7x7 or sudoku 8x8)
## Source code
dCode retains ownership of the source code of the script Sudoku Solver online. Except explicit open source licence (indicated Creative Commons / free), any algorithm, applet, snippet, software (converter, solver, encryption / decryption, encoding / decoding, ciphering / deciphering, translator), or any function (convert, solve, decrypt, encrypt, decipher, cipher, decode, code, translate) written in any informatic langauge (PHP, Java, C#, Python, Javascript, Matlab, etc.) which dCode owns rights will not be released for free. To download the online Sudoku Solver script for offline use on PC, iPhone or Android, ask for price quote on contact page !
|
2020-04-09 06:06:55
|
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|
https://iq.opengenus.org/basics-of-machine-learning-image-classification-techniques/
|
# Basics of Machine Learning Image Classification Techniques
#### machine learning image classification
In this post, we will be focusing on different image classification techniques deployed to make the computer vision as smart as human vision.
• What is Image Classification?
• The pipeline of an image classification task including data preprocessing techniques
• Performance of different Machine Learning techniques on these tasks like:
• Artificial Neural Network
• Convolutional Neural Network
• K nearest neighbor
• Decision tree
• Support Vector Machines
This article assumes that you are interested in the technical know-how of machine learning, image classification in particular!
### What is Image Classification?
Classification between objects is a fairly easy task for us, but it has proved to be a complex one for machines and therefore image classification has been an important task within the field of computer vision.
Image classification refers to the labeling of images into one of a number of predefined classes.
There are potentially n number of classes in which a given image can be classified. Manually checking and classifying images could be a tedious task especially when they are massive in number (say 10,000) and therefore it will be very useful if we could automate this entire process using computer vision.
Some examples of image classification include:
• Labeling an x-ray as cancer or not (binary classification).
• Classifying a handwritten digit (multiclass classification).
• Assigning a name to a photograph of a face (multiclass classification).
The advancements in the field of autonomous driving also serve as a great example of the use of image classification in the real-world. For example, we can build an image classification model that recognizes various objects, such as other vehicles, pedestrians, traffic lights, and signposts on the road.
Now that we have a fair idea of what image classification comprises of, let’s start analyzing the image classification pipeline.
### Structure of an Image Classification Task
1. Image Preprocessing - The aim of this process is to improve the image data(features) by suppressing unwanted distortions and enhancement of some important image features so that our Computer Vision models can benefit from this improved data to work on.
2. Detection of an object - Detection refers to the localization of an object which means the segmentation of the image and identifying the position of the object of interest.
3. Feature extraction and Training- This is a crucial step wherein statistical or deep learning methods are used to identify the most interesting patterns of the image, features that might be unique to a particular class and that will, later on, help the model to differentiate between different classes. This process where the model learns the features from the dataset is called model training.
4. Classification of the object - This step categorizes detected objects into predefined classes by using a suitable classification technique that compares the image patterns with the target patterns.
Let’s discuss the most crucial step which is image preprocessing, in detail!
### Image Pre-processing
Pre-processing is a common name for operations with images at the lowest level of abstraction — both input and output are intensity images.
Need for Image-Preprocessing
Computers are able to perform computations on numbers and is unable to interpret images in the way that we do. We have to somehow convert the images to numbers for the computer to understand.
The aim of pre-processing is an improvement of the image data that suppresses unwilling distortions or enhances some image features important for further processing.
How computers see an '8'
Steps for image pre-processing:
• Resize image
• Data Augmentation
• Gray scaling of image
• Reflection
• Gaussian Blurring
• Histogram Equalization
• Rotation
• Translation
Step 1
In this step, we simply store the path to our image dataset into a variable and then we create a function to load folders containing images into arrays so that computers can deal with it.
Sample code for reading an image dataset with 2 classes:
# importing libraries
from pathlib import Path
import glob
import pandas as pd
images_dir = Path('img')
images = images_dir.glob("*.tif")
train_data = []
counter = 0
for img in images:
counter += 1
if counter <= 130:
train_data.append((img,1))
else:
train_data.append((img,0))
# converting data into pandas dataframe for easy visualization
train_data = pd.DataFrame(train_data,columns=['image','label'],index = None)
Step 2.
Resize image
Some images captured by a camera and fed to our AI algorithm vary in size, therefore, we should establish a base size for all images fed into our AI algorithms by resizing them.
Sample code for resizing images into 229x229 dimensions:
img = cv2.resize(img, (229,229))
Step 3
Data Augmentation
Data augmentation is a way of creating new 'data' with different orientations. The benefits of this are two-fold, the first being the ability to generate 'more data' from limited data and secondly, it prevents overfitting.
Data Augmentation Techniques:
1. Gray Scaling
The image will be converted to gray scale (range of gray shades from white to black) the computer will assign each pixel a value based on how dark it is. All the numbers are put into an array and the computer does computations on that array.
Sample code to convert an RGB(3 channels) image into a Gray scale image:
import cv2
img = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
RGB Image
Grayscale Image:
1. Reflection/Flip
You can flip images horizontally and vertically. Some frameworks do not provide function for vertical flips. But, a vertical flip is equivalent to rotating an image by 180 degrees and then performing a horizontal flip.
Sample Code:
# horizontal flip
img = cv2.flip(img, 0)
# vertical flip
img = cv2.flip(img,1)
Image showing horizontal reflection
1. Gaussian Blurring
Gaussian blur (also known as Gaussian smoothing) is the result of blurring an image by a Gaussian function. It is a widely used effect in graphics software, typically to reduce image noise.
Sample Code:
from scipy import ndimage
img = ndimage.gaussian_filter(img, sigma= 5.11)
Image with blur radius = 5.1
1. Histogram Equalization
Histogram equalization is another image processing technique to increase global contrast of an image using the image intensity histogram. This method needs no parameter, but it sometimes results in an unnatural looking image.
Sample Code
# histogram equalization function
def hist(img):
img_to_yuv = cv2.cvtColor(img,cv2.COLOR_BGR2YUV)
img_to_yuv[:,:,0] = cv2.equalizeHist(img_to_yuv[:,:,0])
hist_equalization_result = cv2.cvtColor(img_to_yuv, cv2.COLOR_YUV2BGR)
return hist_equalization_result
1. Rotation
This is yet another image augmentation technique. Rotating an image might not preserve its original dimensions (depending on what angle you choose to rotate it with )
Sample Code
import random
# function for rotation
def rotation(img):
rows,cols = img.shape[0],img.shape[1]
randDeg = random.randint(-180, 180)
matrix = cv2.getRotationMatrix2D((cols/2, rows/2), randDeg, 0.70)
rotated = cv2.warpAffine(img, matrix, (rows, cols), borderMode=cv2.BORDER_CONSTANT,borderValue=(144, 159, 162))
return rotated
The images are rotated by 90 degrees clockwise with respect to the previous one, as we move from left to right.
1. Translation
Translation just involves moving the image along the X or Y direction (or both).
This method of augmentation is very useful as most objects can be located at almost anywhere in the image. This forces our feature extractor to look everywhere.
Sample Code
img = cv2.warpAffine(img, np.float32([[1, 0, 84], [0, 1, 56]]), (img.shape[0], img.shape[1]),
borderMode=cv2.BORDER_CONSTANT,borderValue=(144, 159, 162))
## Image Classification Techniques
We will start with some statistical machine learning classifiers like Support Vector Machine and Decision Tree and then move on to deep learning architectures like Convolutional Neural Networks.
To support their performance analysis, the results from an Image classification task used to differentiate lymphoblastic leukemia cells from non-lymphoblastic ones have been provided. The features have been extracted using a convolutional neural network, which will also be discussed as one of our classifiers. This is because deep learning models have achieved state of the art results in the feature extraction process.
Different classifiers are then added on top of this feature extractor to classify images.
## 1. Support Vector Machines
It is a supervised machine learning algorithm used for both regression and classification problems.
When used for classification purposes, it separates the classes using a linear boundary.
It builds a hyper-plane or a set of hyper-planes in a high dimensional space and good separation between the two classes is achieved by the hyperplane that has the largest distance to the nearest training data point of any class.
The real power of this algorithm depends on the kernel function being used.
The most commonly used kernels are:
• Linear Kernel
• Gaussian Kernel
• Polynomial Kernel
Code Snippet:
This is the base model/feature extractor using Convolutional Neural Network, using Keras with Tensorflow backend
model = Sequential()
model_feat = Model(inputs=model.input,outputs=model.get_layer('dense_1').output)
feat_train = model_feat.predict(X_train)
Fitting of SVM as a classifier
svm = SVC(kernel='rbf')
svm.fit(feat_train,np.argmax(y_train,axis=1))
svm.score(feat_test,np.argmax(y_test,axis=1))
Accuracy score on test data: 85.68
## 2. Decision Trees
It is also a supervised machine learning algorithm, which at its core is the tree data structure only, using a couple of if/else statements on the features selected.
Decision trees are based on a hierarchical rule-based method and permits the acceptance and rejection of class labels at each intermediary stage/level.
This method consists of 3 parts:
• Partitioning the nodes
• Finding the terminal nodes
• Allocation of the class label to terminal node
Code
Feature Extractor
model = Sequential()
model_feat = Model(inputs=model.input,outputs=model.get_layer('dense_2').output)
feat_train = model_feat.predict(X_train)
Decision Tree Classifier
dt = DecisionTreeClassifier(criterion = "entropy", random_state = 100,max_depth=3, min_samples_leaf=5)
dt.fit(feat_train,np.argmax(y_train,axis=1))
dt.score(feat_test,np.argmax(y_test,axis=1))
Accuracy on test set: 84.61
## 3. K Nearest Neighbor
The k-nearest neighbor is by far the most simple machine learning algorithm.
This algorithm simply relies on the distance between feature vectors and classifies unknown data points by finding the most common class among the k-closest examples.
Here we can see there are two categories of images and that each of the data points within each respective category are grouped relatively close together in an n-dimensional space.
In order to apply the k-nearest Neighbor classification, we need to define a distance metric or similarity function. Common choices include the Euclidean distance and Manhattan distance
Code
Base Model/feature extractor
model = Sequential()
model_feat = Model(inputs=model.input,outputs=model.get_layer('dense_2').output)
feat_train = model_feat.predict(X_train)
KNN classifier
knn = KNeighborsClassifier(n_neighbors=12)
knn.fit(feat_train,np.argmax(y_train,axis=-1))
knn.score(feat_test,np.argmax(y_test,axis=1))
Accuracy on test set: 86.32
## 4. Artificial Neural Networks
Inspired by the properties of biological neural networks, Artificial Neural Networks are statistical learning algorithms and are used for a variety of tasks, from relatively simple classification tasks to computer vision and speech recognition.
ANNs are implemented as a system of interconnected processing elements, called nodes, which are functionally analogous to biological neurons.The connections between different nodes have numerical values, called weights, and by altering these values in a systematic way, the network is eventually able to approximate the desired function.
The hidden layers can be thought of as individual feature detectors, recognizing more and more complex patterns in the data as it is propagated throughout the network. For example, if the network is given a task to recognize a face, the first hidden layer might act as a line detector, the second hidden takes these lines as input and puts them together to form a nose, the third hidden layer takes the nose and matches it with an eye and so on, until finally the whole face is constructed. This hierarchy enables the network to eventually recognize very complex objects.
Code
ANN as feature extractor using softmax classifier
model_ann = Sequential()
history = model_ann.fit(X_train, y_train,epochs=100,batch_size=100)
history
Accuracy on test data: 83.1
This result has been recorded for 100 epochs, and the accuracy improves as the epochs are further increased.
Link to study ANN in detail
## 5. Convolutional Neural Networks
Convolutional neural networks (CNN) is a special architecture of artificial neural networks. CNNs uses some of its features of visual cortex and have therefore achieved state of the art results in computer vision tasks.
Let’s cover the use of CNN in more detail.
Convolutional neural networks are comprised of two very simple elements, namely convolutional layers and pooling layers.
Although simple, there are near-infinite ways to arrange these layers for a given computer vision problem.
The elements of a convolutional neural network, such as convolutional and pooling layers, are relatively straightforward to understand.
The challenging part of using convolutional neural networks in practice is how to design model architectures that best use these simple elements.
Code
CNN as feature extractor using softmax classifier
model = Sequential()
batch_size = 100
epochs= 100
optimizer = keras.optimizers.rmsprop(lr = 0.0001, decay = 1e-6)
model.compile(loss = 'binary_crossentropy',optimizer = optimizer, metrics = ['accuracy',keras_metrics.precision(), keras_metrics.recall()])
history = model.fit(X_train,y_train,steps_per_epoch = int(len(X_train)/batch_size),epochs=epochs)
history
Accuracy on test data with 100 epochs: 87.11
Since this model gave the best result amongst all, it was trained longer and it achieved 91% accuracy with 300 epochs.
### Performance evaluation
Classifier Accuracy Precision Recall ROC
SVM 85.68% 0.86 0.87 0.86
Decision Trees 84.61% 0.85 0.84 0.82
KNN 86.32% 0.86 0.86 0.88
ANN(for 100 epochs) 83.10% 0.88 0.87 0.88
CNN(for 300 epochs) 91.11% 0.93 0.89 0.97
### Conclusion
We can conclude from the performance table, that Convolutional Neural networks deliver the best results in computer vision tasks.
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2019-08-23 04:52:48
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https://www.calpaininhibitor.com/2019/06/19/7661/
|
# Tcher-bird) was negatively related with quite a few. In contrast, practically half in the species
Tcher-bird) was negatively related with quite a few. In contrast, practically half in the species do not have powerful associations with any other folks. We also identified evidence in Fig. 1 of “compartmentalism” (Bascompte 2010), with nine species much more strongly linked with each other than with other species within the assemblage. One more feature of networks of species is definitely the occurrence of “asymmetric links.” We also found evidence of these; by way of example, the dusky woodswallow was strongly linked together with the white-plumed honeyeater within the sense that the second species practically generally occurred when the first did (Fig. 1). However, the reverse was not the case.Upper limit and P-value are not available for estimates equal to 0.cascades; Koh et al. 2004; Bascompte 2009). Far better understanding can also be essential for quantifying the effectiveness of restoration activities (as shown in our case study; see Fig. 2). Figuring out the strength of associations is also crucial since it can indicate which species may be those most vulnerable to decline or extinction if a network is disrupted (Saavedra et al. 2011) and conversely how network architecture can influence other processes like competitors (Bastolla et al. 2009). Finally, our strategy has considerable potential application in conservation since ecologists need to have to focus not merely on maintaining species, but additionally on conserving species interactions (Tylianakis et al. 2010). Our new strategy for examining species pairwise associations goes beyond straightforward descriptions of your count, identity, or abundance of species, as does the approach of Ovaskainen et al. (2010). Both permit the exploration of patterns of association and the way the patterns modify with key aspects for example vegetation sort (as in our instance), or habitat structure, season, plus the co-occurrence of dominant species (either good or unfavorable). These approaches as a result allow informative comparisons PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/21343449 between species assemblages in distinctive environments. Our method also enables exploration not merely of direct association effects in between pairs of species, but also with the impacts of second-order associations, which come to be apparent when a dominant species is removed, for example a reverse keystone species (sensu Montague-Drake et al. 2011). This can be achieved by comparing the odds ratios from two various analyses of species pairwise associations, one for websites exactly where the dominant species occurs and one for internet sites where it does not. Notably, several previous studies quantifying the strength of associations between species have generally been within folks on the exact same species (Mersch et al. 2013) or a tiny number of species (Estes et al. 2011), rather than the bulk of a species-rich assemblage (but see Tylianakis et al. 2007; Gotelli and Ulrich 2010; SteeleExplanation in the crucial findings in our case studyThere are numerous underlying reasons for associations involving species. Functionally related or Anemosapogenin manufacturer closely associated taxa could be adapted to related environments or obtain mutual added benefits; as an example, enhanced foraging possibilities can result in mixed-species feeding flocks and create a greater number of species associations (Bell 1980; Sridhar et al. 2012). Species may also share comparable nesting specifications or predator avoidance tactics, hence resulting in optimistic associations. Species could also opt for habitat applying info gleaned from other species present at a location (Smith and Hellman 2002), specifically a species that is definitely pretty comparable to its.
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2020-10-24 03:28:46
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https://mizar.uwb.edu.pl/version/current/html/mesfun13.html
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:: Fubini's Theorem
:: by Noboru Endou
::
:: Copyright (c) 2019-2021 Association of Mizar Users
theorem Th15: :: MESFUN13:1
for X being set
for A being Subset of X
for f being b1 -defined Relation holds f | (A ) = f | ((dom f) \ A)
proof end;
theorem Th10: :: MESFUN13:2
for X being set
for f being PartFunc of X,ExtREAL holds great_eq_dom (f,+infty) = eq_dom (f,+infty)
proof end;
theorem :: MESFUN13:3
for X being set
for f being PartFunc of X,ExtREAL holds less_eq_dom (f,-infty) = eq_dom (f,-infty)
proof end;
theorem :: MESFUN13:4
for X being set
for f being PartFunc of X,ExtREAL
for er being ExtReal holds great_eq_dom (f,er) misses less_dom (f,er)
proof end;
theorem :: MESFUN13:5
for X being set
for f being PartFunc of X,ExtREAL holds dom f = ((eq_dom (f,-infty)) \/ ((great_dom (f,-infty)) /\ (less_dom (f,+infty)))) \/ (eq_dom (f,+infty))
proof end;
theorem Th29: :: MESFUN13:6
for X being non empty set
for f being PartFunc of X,ExtREAL
for x being Element of X holds
( (max+ f) . x <= |.f.| . x & (max- f) . x <= |.f.| . x )
proof end;
theorem Th27: :: MESFUN13:7
for X1, X2 being non empty set
for f being PartFunc of [:X1,X2:],ExtREAL
for x being Element of X1
for y being Element of X2 holds
( ProjPMap1 (|.f.|,x) = |.(ProjPMap1 (f,x)).| & ProjPMap2 (|.f.|,y) = |.(ProjPMap2 (f,y)).| )
proof end;
registration
let X be non empty set ;
let S be SigmaField of X;
let E be Element of S;
existence
ex b1 being PartFunc of X,ExtREAL st b1 is E -measurable
proof end;
end;
theorem Th9: :: MESFUN13:8
for X being non empty set
for S being SigmaField of X
for E being Element of S
for f being b3 -measurable PartFunc of X,ExtREAL st dom f = E holds
( eq_dom (f,+infty) in S & eq_dom (f,-infty) in S )
proof end;
theorem Th1: :: MESFUN13:9
for X1, X2 being non empty set
for S1 being SigmaField of X1
for S2 being SigmaField of X2
for M1 being sigma_Measure of S1
for M2 being sigma_Measure of S2
for E being Element of sigma (measurable_rectangles (S1,S2))
for f being b7 -measurable PartFunc of [:X1,X2:],ExtREAL st M1 is sigma_finite & M2 is sigma_finite & dom f = E holds
( Integral (M1,(Integral2 (M2,|.f.|))) = Integral ((Prod_Measure (M1,M2)),|.f.|) & Integral (M2,(Integral1 (M1,|.f.|))) = Integral ((Prod_Measure (M1,M2)),|.f.|) )
proof end;
Lm1: for X1, X2 being non empty set
for S1 being SigmaField of X1
for S2 being SigmaField of X2
for M1 being sigma_Measure of S1
for M2 being sigma_Measure of S2
for f being PartFunc of [:X1,X2:],ExtREAL st M1 is sigma_finite & M2 is sigma_finite & f is_integrable_on Prod_Measure (M1,M2) holds
( Integral (M1,(Integral2 (M2,|.f.|))) < +infty & Integral (M2,(Integral1 (M1,|.f.|))) < +infty )
proof end;
Lm2: for X1, X2 being non empty set
for S1 being SigmaField of X1
for S2 being SigmaField of X2
for M1 being sigma_Measure of S1
for M2 being sigma_Measure of S2
for E being Element of sigma (measurable_rectangles (S1,S2))
for f being b7 -measurable PartFunc of [:X1,X2:],ExtREAL st M1 is sigma_finite & M2 is sigma_finite & E = dom f & ( Integral (M2,(Integral1 (M1,|.f.|))) < +infty or Integral (M1,(Integral2 (M2,|.f.|))) < +infty ) holds
f is_integrable_on Prod_Measure (M1,M2)
proof end;
theorem :: MESFUN13:10
for X1, X2 being non empty set
for S1 being SigmaField of X1
for S2 being SigmaField of X2
for M1 being sigma_Measure of S1
for M2 being sigma_Measure of S2
for E being Element of sigma (measurable_rectangles (S1,S2))
for f being b7 -measurable PartFunc of [:X1,X2:],ExtREAL st M1 is sigma_finite & M2 is sigma_finite & E = dom f holds
( f is_integrable_on Prod_Measure (M1,M2) iff Integral (M2,(Integral1 (M1,|.f.|))) < +infty ) by ;
theorem :: MESFUN13:11
for X1, X2 being non empty set
for S1 being SigmaField of X1
for S2 being SigmaField of X2
for M1 being sigma_Measure of S1
for M2 being sigma_Measure of S2
for E being Element of sigma (measurable_rectangles (S1,S2))
for f being b7 -measurable PartFunc of [:X1,X2:],ExtREAL st M1 is sigma_finite & M2 is sigma_finite & E = dom f holds
( f is_integrable_on Prod_Measure (M1,M2) iff Integral (M1,(Integral2 (M2,|.f.|))) < +infty ) by ;
theorem Th4: :: MESFUN13:12
for X1, X2 being non empty set
for S1 being SigmaField of X1
for S2 being SigmaField of X2
for M2 being sigma_Measure of S2
for E being Element of sigma (measurable_rectangles (S1,S2))
for U being Element of S1
for f being b6 -measurable PartFunc of [:X1,X2:],ExtREAL st M2 is sigma_finite & E = dom f holds
Integral2 (M2,|.f.|) is U -measurable
proof end;
theorem Th5: :: MESFUN13:13
for X1, X2 being non empty set
for S1 being SigmaField of X1
for S2 being SigmaField of X2
for M1 being sigma_Measure of S1
for E being Element of sigma (measurable_rectangles (S1,S2))
for V being Element of S2
for f being b6 -measurable PartFunc of [:X1,X2:],ExtREAL st M1 is sigma_finite & E = dom f holds
Integral1 (M1,|.f.|) is V -measurable
proof end;
theorem :: MESFUN13:14
for X1, X2 being non empty set
for S1 being SigmaField of X1
for S2 being SigmaField of X2
for M1 being sigma_Measure of S1
for M2 being sigma_Measure of S2
for f being PartFunc of [:X1,X2:],ExtREAL st M2 is sigma_finite & f is_integrable_on Prod_Measure (M1,M2) holds
( Integral (M1,(max+ (Integral2 (M2,|.f.|)))) = Integral (M1,(Integral2 (M2,|.f.|))) & Integral (M1,(max- (Integral2 (M2,|.f.|)))) = 0 )
proof end;
theorem :: MESFUN13:15
for X1, X2 being non empty set
for S1 being SigmaField of X1
for S2 being SigmaField of X2
for M1 being sigma_Measure of S1
for M2 being sigma_Measure of S2
for f being PartFunc of [:X1,X2:],ExtREAL st M1 is sigma_finite & f is_integrable_on Prod_Measure (M1,M2) holds
( Integral (M2,(max+ (Integral1 (M1,|.f.|)))) = Integral (M2,(Integral1 (M1,|.f.|))) & Integral (M2,(max- (Integral1 (M1,|.f.|)))) = 0 )
proof end;
:: Markov's inequality
theorem Th14: :: MESFUN13:16
for X being non empty set
for S being SigmaField of X
for M being sigma_Measure of S
for E being Element of S
for f being b4 -measurable PartFunc of X,ExtREAL
for er being ExtReal st dom f = E & f is nonnegative & er >= 0 holds
er * (M . (great_eq_dom (f,er))) <= Integral (M,f)
proof end;
theorem Th21: :: MESFUN13:17
for X being non empty set
for S being SigmaField of X
for M being sigma_Measure of S
for f, g being PartFunc of X,ExtREAL st f is_integrable_on M & g is_integrable_on M holds
( Integral (M,(f + g)) = (Integral (M,(f | ((dom f) /\ (dom g))))) + (Integral (M,(g | ((dom f) /\ (dom g))))) & Integral (M,(f - g)) = (Integral (M,(f | ((dom f) /\ (dom g))))) - (Integral (M,(g | ((dom f) /\ (dom g))))) )
proof end;
theorem :: MESFUN13:18
for X being non empty set
for S being SigmaField of X
for M being sigma_Measure of S
for f being PartFunc of X,ExtREAL holds
( f is_integrable_on M iff ( max+ f is_integrable_on M & max- f is_integrable_on M ) )
proof end;
theorem :: MESFUN13:19
for X being non empty set
for S being SigmaField of X
for A, B being Element of S
for f being PartFunc of X,ExtREAL st B c= A & f | A is B -measurable holds
f is B -measurable
proof end;
definition
let X be non empty set ;
let S be SigmaField of X;
let M be sigma_Measure of S;
let f be PartFunc of X,ExtREAL;
pred f is_a.e.integrable_on M means :: MESFUN13:def 1
ex A being Element of S st
( M . A = 0 & A c= dom f & f | (A ) is_integrable_on M );
end;
:: deftheorem defines is_a.e.integrable_on MESFUN13:def 1 :
for X being non empty set
for S being SigmaField of X
for M being sigma_Measure of S
for f being PartFunc of X,ExtREAL holds
( f is_a.e.integrable_on M iff ex A being Element of S st
( M . A = 0 & A c= dom f & f | (A ) is_integrable_on M ) );
theorem Th16: :: MESFUN13:20
for X being non empty set
for S being SigmaField of X
for M being sigma_Measure of S
for f being PartFunc of X,ExtREAL st f is_a.e.integrable_on M holds
dom f in S
proof end;
theorem :: MESFUN13:21
for X being non empty set
for S being SigmaField of X
for M being sigma_Measure of S
for f being PartFunc of X,ExtREAL st f is_integrable_on M holds
f is_a.e.integrable_on M
proof end;
definition
let X be non empty set ;
let S be SigmaField of X;
let M be sigma_Measure of S;
let f be PartFunc of X,ExtREAL;
pred f is_a.e.finite M means :: MESFUN13:def 2
ex A being Element of S st
( M . A = 0 & A c= dom f & f | (A ) is PartFunc of X,REAL );
end;
:: deftheorem defines is_a.e.finite MESFUN13:def 2 :
for X being non empty set
for S being SigmaField of X
for M being sigma_Measure of S
for f being PartFunc of X,ExtREAL holds
( f is_a.e.finite M iff ex A being Element of S st
( M . A = 0 & A c= dom f & f | (A ) is PartFunc of X,REAL ) );
theorem :: MESFUN13:22
for X being non empty set
for S being SigmaField of X
for M being sigma_Measure of S
for E being Element of S
for f being b4 -measurable PartFunc of X,ExtREAL st dom f = E holds
( f is_a.e.finite M iff M . ((eq_dom (f,+infty)) \/ (eq_dom (f,-infty))) = 0 )
proof end;
theorem Th19: :: MESFUN13:23
for X being non empty set
for S being SigmaField of X
for M being sigma_Measure of S
for f being PartFunc of X,ExtREAL st f is_integrable_on M holds
( M . (eq_dom (f,+infty)) = 0 & M . (eq_dom (f,-infty)) = 0 & f is_a.e.finite M & ( for r being Real st r > 0 holds
M . (great_eq_dom (|.f.|,r)) < +infty ) )
proof end;
theorem Th20: :: MESFUN13:24
for X1, X2 being non empty set
for S1 being SigmaField of X1
for S2 being SigmaField of X2
for M1 being sigma_Measure of S1
for M2 being sigma_Measure of S2
for f being PartFunc of [:X1,X2:],ExtREAL st M1 is sigma_finite & M2 is sigma_finite & f is_integrable_on Prod_Measure (M1,M2) holds
( Integral1 (M1,(max+ f)) is_integrable_on M2 & Integral2 (M2,(max+ f)) is_integrable_on M1 & Integral1 (M1,(max- f)) is_integrable_on M2 & Integral2 (M2,(max- f)) is_integrable_on M1 & Integral1 (M1,|.f.|) is_integrable_on M2 & Integral2 (M2,|.f.|) is_integrable_on M1 )
proof end;
theorem :: MESFUN13:25
for X being non empty set
for S being SigmaField of X
for M being sigma_Measure of S
for E being Element of S
for f being b4 -measurable PartFunc of X,ExtREAL st dom f c= E & f is_a.e.integrable_on M holds
f is_integrable_on M
proof end;
theorem Th23: :: MESFUN13:26
for X being non empty set
for S being SigmaField of X
for M being sigma_Measure of S
for A being Element of S
for f being PartFunc of X,ExtREAL st M . A = 0 & A c= dom f & f | (A ) is_integrable_on M holds
ex g being PartFunc of X,ExtREAL st
( dom g = dom f & f | (A ) = g | (A ) & g is_integrable_on M & Integral (M,(f | (A ))) = Integral (M,g) )
proof end;
theorem :: MESFUN13:27
for X1, X2 being non empty set
for S1 being SigmaField of X1
for S2 being SigmaField of X2
for M1 being sigma_Measure of S1
for M2 being sigma_Measure of S2
for f being PartFunc of [:X1,X2:],ExtREAL st M1 is sigma_finite & M2 is sigma_finite & f is_integrable_on Prod_Measure (M1,M2) holds
( Integral ((Prod_Measure (M1,M2)),f) = (Integral (M2,(Integral1 (M1,(max+ f))))) - (Integral (M2,(Integral1 (M1,(max- f))))) & Integral ((Prod_Measure (M1,M2)),f) = (Integral (M1,(Integral2 (M2,(max+ f))))) - (Integral (M1,(Integral2 (M2,(max- f))))) )
proof end;
theorem :: MESFUN13:28
for X1, X2 being non empty set
for S1 being SigmaField of X1
for S2 being SigmaField of X2
for M1 being sigma_Measure of S1
for E being Element of sigma (measurable_rectangles (S1,S2))
for y being Element of X2 holds
( ( M1 . (Measurable-Y-section (E,y)) <> 0 implies (Integral1 (M1,(Xchi (E,[:X1,X2:])))) . y = +infty ) & ( M1 . (Measurable-Y-section (E,y)) = 0 implies (Integral1 (M1,(Xchi (E,[:X1,X2:])))) . y = 0 ) )
proof end;
theorem :: MESFUN13:29
for X1, X2 being non empty set
for S1 being SigmaField of X1
for S2 being SigmaField of X2
for M2 being sigma_Measure of S2
for E being Element of sigma (measurable_rectangles (S1,S2))
for x being Element of X1 holds
( ( M2 . (Measurable-X-section (E,x)) <> 0 implies (Integral2 (M2,(Xchi (E,[:X1,X2:])))) . x = +infty ) & ( M2 . (Measurable-X-section (E,x)) = 0 implies (Integral2 (M2,(Xchi (E,[:X1,X2:])))) . x = 0 ) )
proof end;
:: Fubinis theorem
theorem :: MESFUN13:30
for X1, X2 being non empty set
for S1 being SigmaField of X1
for S2 being SigmaField of X2
for M1 being sigma_Measure of S1
for M2 being sigma_Measure of S2
for f being PartFunc of [:X1,X2:],ExtREAL
for SX1 being Element of S1 st M1 is sigma_finite & M2 is sigma_finite & f is_integrable_on Prod_Measure (M1,M2) & X1 = SX1 holds
ex U being Element of S1 st
( M1 . U = 0 & ( for x being Element of X1 st x in U holds
ProjPMap1 (f,x) is_integrable_on M2 ) & (Integral2 (M2,|.f.|)) | (U ) is PartFunc of X1,REAL & Integral2 (M2,f) is SX1 \ U -measurable & (Integral2 (M2,f)) | (U ) is_integrable_on M1 & (Integral2 (M2,f)) | (U ) in L1_Functions M1 & ex g being Function of X1,ExtREAL st
( g is_integrable_on M1 & g | (U ) = (Integral2 (M2,f)) | (U ) & Integral ((Prod_Measure (M1,M2)),f) = Integral (M1,g) ) )
proof end;
theorem :: MESFUN13:31
for X1, X2 being non empty set
for S1 being SigmaField of X1
for S2 being SigmaField of X2
for M1 being sigma_Measure of S1
for M2 being sigma_Measure of S2
for f being PartFunc of [:X1,X2:],ExtREAL
for SX2 being Element of S2 st M1 is sigma_finite & M2 is sigma_finite & f is_integrable_on Prod_Measure (M1,M2) & X2 = SX2 holds
ex V being Element of S2 st
( M2 . V = 0 & ( for y being Element of X2 st y in V holds
ProjPMap2 (f,y) is_integrable_on M1 ) & (Integral1 (M1,|.f.|)) | (V ) is PartFunc of X2,REAL & Integral1 (M1,f) is SX2 \ V -measurable & (Integral1 (M1,f)) | (V ) is_integrable_on M2 & (Integral1 (M1,f)) | (V ) in L1_Functions M2 & ex g being Function of X2,ExtREAL st
( g is_integrable_on M2 & g | (V ) = (Integral1 (M1,f)) | (V ) & Integral ((Prod_Measure (M1,M2)),f) = Integral (M2,g) ) )
proof end;
theorem :: MESFUN13:32
for X1, X2 being non empty set
for S1 being SigmaField of X1
for S2 being SigmaField of X2
for M1 being sigma_Measure of S1
for M2 being sigma_Measure of S2
for f being PartFunc of [:X1,X2:],ExtREAL st M1 is sigma_finite & M2 is sigma_finite & f is_integrable_on Prod_Measure (M1,M2) & ( for x being Element of X1 holds (Integral2 (M2,|.f.|)) . x < +infty ) holds
( ( for x being Element of X1 holds ProjPMap1 (f,x) is_integrable_on M2 ) & ( for U being Element of S1 holds Integral2 (M2,f) is U -measurable ) & Integral2 (M2,f) is_integrable_on M1 & Integral ((Prod_Measure (M1,M2)),f) = Integral (M1,(Integral2 (M2,f))) & Integral2 (M2,f) in L1_Functions M1 )
proof end;
theorem :: MESFUN13:33
for X1, X2 being non empty set
for S1 being SigmaField of X1
for S2 being SigmaField of X2
for M1 being sigma_Measure of S1
for M2 being sigma_Measure of S2
for f being PartFunc of [:X1,X2:],ExtREAL st M1 is sigma_finite & M2 is sigma_finite & f is_integrable_on Prod_Measure (M1,M2) & ( for y being Element of X2 holds (Integral1 (M1,|.f.|)) . y < +infty ) holds
( ( for y being Element of X2 holds ProjPMap2 (f,y) is_integrable_on M1 ) & ( for V being Element of S2 holds Integral1 (M1,f) is V -measurable ) & Integral1 (M1,f) is_integrable_on M2 & Integral ((Prod_Measure (M1,M2)),f) = Integral (M2,(Integral1 (M1,f))) & Integral1 (M1,f) in L1_Functions M2 )
proof end;
|
2022-07-02 06:15:04
|
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|
https://lists.gnu.org/archive/html/bug-lilypond/2014-08/msg00030.html
|
bug-lilypond
[Top][All Lists]
Re: barcheck failure with partial in middle of piece
From: David Kastrup Subject: Re: barcheck failure with partial in middle of piece Date: Sat, 09 Aug 2014 00:08:00 +0200 User-agent: Gnus/5.13 (Gnus v5.13) Emacs/24.4.50 (gnu/linux)
Paul Morris <address@hidden> writes:
> Having looked into this some more, it seems that (one place) where I
> went wrong was assuming that I needed to have matching \partial
> commands in each parallel context, when it seems that a \partial only
> needs to be in one of them.
It is needed at least once per Timing context (usually Timing is just
the same as Score, but one can create polyrhythmic context hierarchies),
just like \time 3/4 and similar.
> the docs? Although maybe that wouldn't be needed after David's new
> patch?
Pretty irrelevant after the patch.
--
David Kastrup
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2019-09-20 23:55:14
|
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|
https://math.stackexchange.com/questions/987492/if-mub-0-then-mu-yb-x-0
|
# If $\mu(B)=0$ then $\mu_y(B_x)=0$
Let $B_x$ be the $x$-section of a $\mu_x\otimes \mu_y$-measurable set $B$, where $\mu_x\otimes \mu_y$, which I will call $\mu$, is the Lebesgue extension of the product measure $\mu_x\times \mu_y$ (both measures being $\sigma$-additive complete measures defined on $\sigma$-algebras of subsets of $X$ and $Y$, respectively), defined by $$B_x=\{y\in Y:(x,y)\in B\}$$ I read that if $\mu(B)=0$ then for almost all $x\in X$ $\mu_y(B_x)=0$ but, although it sounds very intuitive, I cannot prove it to myself. Could anybody explain this interesting fact? I $\infty$-ly thank you!
Recall that $\mu(B)=\int_X\mu_Y(B_x)\mathrm d\mu_X(x)$ hence, if $\mu(B)=0$ then $\mu_Y(B_x)=0$ for $\mu_X$-almost every $x$.
To show this, consider $A_n=\{x\in X\mid n\mu_Y(B_x)\geqslant1\}$ and note that, for every $n$, $0=n\mu(B)\geqslant\int_{A_n}n\mu_Y(B_x)\mathrm d\mu_X(x)\geqslant\mu_X(A_n)$ hence $\mu_X(A_n)=0$. This implies that $\mu_X(A_0)=0$ where $A_0=\bigcup\limits_{n\geqslant1}A_n=\{x\in X\mid\mu_Y(B_x)\ne0\}$, QED.
|
2019-10-20 08:46:52
|
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|
http://xuweitao.me/balanced-brackets.html
|
# Balanced Brackets
Problem Information:
AC date : 2017-05-15
Category : data structure->stack
## Question
A bracket is considered to be any one of the following characters: (, ), {, }, [, or ].
Two brackets are considered to be a matched pair if the an opening bracket (i.e., (, [, or {) occurs to the left of a closing bracket (i.e., ), ], or }) of the exact same type. There are three types of matched pairs of brackets: [], {}, and ().
A matching pair of brackets is not balanced if the set of brackets it encloses are not matched. For example, {[(])} is not balanced because the contents in between { and } are not balanced. The pair of square brackets encloses a single, unbalanced opening bracket, (, and the pair of parentheses encloses a single, unbalanced closing square bracket, ].
By this logic, we say a sequence of brackets is considered to be balanced if the following conditions are met:
• It contains no unmatched brackets.
• The subset of brackets enclosed within the confines of a matched pair of brackets is also a matched pair of brackets.
Given strings of brackets, determine whether each sequence of brackets is balanced. If a string is balanced, print YES on a new line; otherwise, print NO on a new line.
### Input Format
The first line contains a single integer, $$n$$, denoting the number of strings. Each line of the subsequent lines consists of a single string, , denoting a sequence of brackets.
### Constraints
• $1 \le n \le 10^3$
• $$1 \le len_s \le 10^3$$, where $$len_s$$ is the length of the sequence.
• Each character in the sequence will be a bracket (i.e., {, }, (, ), [, and ]).
### Output Format
For each string, print whether or not the string of brackets is balanced on a new line. If the brackets are balanced, print YES; otherwise, print NO.
3
{[()]}
{[(])}
{{[[(())]]}}
YES
NO
YES
### C++
//head.h
using namespace std;
int main() {
int t;
cin >> t;
string left = "([{";
string right = ")]}";
for (int a0 = 0; a0 < t; a0++) {
string s;
cin >> s;
int i = 0;
bool flag = 1;
stack<char> brackets;
while (i < s.size()) {
if (left.find(s[i]) != string::npos)
brackets.push(s[i]);
else if (!brackets.empty() && left[right.find(s[i])] == brackets.top())
brackets.pop();
else {
flag = 0;
break;
}
i++;
}
if (!brackets.empty())
flag = 0;
if (flag)
cout << "YES" << endl;
else
cout << "NO" << endl;
}
return 0;
}
2017-05-15 17:10
|
2018-06-18 07:21:23
|
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|
https://socratic.org/questions/observation-of-sodium-sulfite-solid-added-to-a-little-alkaline-potassium-permang
|
# Observation of sodium sulfite solid added to a little alkaline potassium permanganate?
Jun 5, 2018
Well what did you see? The colour would dissipate certainly, but was there a brown precipitate? Did it go green..?
#### Explanation:
In acidic medium sulfite would be oxidized to sulfate, and permanganate reduced to $M {n}^{2 +}$
$S {O}_{3}^{2 -} + {H}_{2} O \left(l\right) \rightarrow S {O}_{4}^{2 -} + 2 {H}^{+} + 2 {e}^{-}$ $\left(i\right)$
And of course permanganate reduced to $M {n}^{2 +}$...
$M n {O}_{4}^{-} + 8 {H}^{+} + 5 {e}^{-} \rightarrow M {n}^{2 +} + 4 {H}_{2} O$ $\left(i i\right)$
But this is in an ACID medium. In a basic medium, which was specified by the question, more likely the reduction product would be manganate ion, $M n {O}_{4}^{2 -}$, $M n \left(V I +\right)$, OR $M n {O}_{2} \left(s\right)$...i.e. a hydrous oxide of $M n \left(I V +\right)$...
For manganate ion....
${\underbrace{M n {O}_{4}^{-}}}_{\text{red" +e^(-) rarr underbrace(MnO_4^(2-))_"green}}$
...or MORE LIKELY.....
$M n {O}_{4}^{-} + 2 {H}_{2} O + 3 {e}^{-} \rightarrow {\underbrace{M n {O}_{2} \left(s\right)}}_{\text{brown solid}} \downarrow + 4 H {O}^{-}$ $\left(i i i\right)$
I am inclined to think that $\left(i i i\right)$ is the reduction that occurred. But what do I know? I did not do the experiment. And so we cross multiply...
$3 \times \left(i\right) + 2 \times \left(i i i\right)$
$3 S {O}_{3}^{2 -} + 2 M n {O}_{4}^{-} + {H}_{2} O \left(l\right) \rightarrow 2 M n {O}_{2} \left(s\right) + 3 S {O}_{4}^{2 -} + 2 H {O}^{-}$
The which is balanced with respect to mass and charge... Whew.
See here for another example of this process...
|
2019-08-20 18:33:28
|
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|
http://docs.itascacg.com/flac3d700/common/sel/doc/manual/sel_manual/nodes/commands/cmd_structure.node.initialize.html
|
# structure node initialize command
Syntax
structure node initialize keyword ... <range>
Primary keywords:
Initialize quantities on all structure nodes in the range. Note that positions can only be specified in the global system.
Be aware that in the structural element logic, node velocities and displacements are stored in the local system. This means that changes to the local system can change the values in the global system. This is particularly important because the node local system is not calculated for a given structural element system until the first cycle or step, until then the node system is the default, which corresponds to the global system. When the first cycle command occurs, the node local system is adjusted and any values of velocity that have been assigned will likely change their direction in the global system.
The best way to handle this is to emit a model cycle 0 command before assigning velocities to nodes—this will cause the local node system to be updated.
displacement v
translational displacement
displacement-x f
translational displacement ($$x$$-component)
displacement-y f
translational displacement ($$y$$-component)
displacement-z f
translational displacement ($$z$$-component)
displacement-rotational v
rotational displacement
displacement-rotational-x f
rotational displacement ($$x$$-component)
displacement-rotational-y f
translational displacement ($$y$$-component)
displacement-rotational-z f
translational displacement ($$z$$-component)
position v
position of node (global system). This is used for positioning of a structural element grid; must be used after creating the node, but before executing any cycles. Any node that is moved into a zone (see the structure link list command) will have its link deleted (if one is present) and will have a new link created with attachment conditions corresponding to the type of structural element using the node (see this table). If more than one element type is using the node, then the attachment condition will correspond with the first element type in the following list: liner, geogrid, pile, cable, shell, and beam. Thus, if a node is being used by both a geogrid and a cable, then the attachment condition after moving this node will correspond with that of a geogrid.
position-x f
$$x$$-coordinate of node (global system). See position above.
position-y f
$$y$$-coordinate of node (global system). See position above.
position-z f
$$z$$-coordinate of node (global system). See position above.
ratio-target f
Sets the target local force ratio that is considered to be converged for mechanical calculations. The default value is 1e-4. A local force ratio of this value will result in a convergence value of 1.0 for the node. See the convergence keyword in the model solve command.
velocity v
translational velocity
velocity-x f
translational velocity ($$x$$-component)
velocity-y f
translational velocity ($$y$$-component)
velocity-z f
translational velocity ($$z$$-component)
velocity-rotational v
rotational velocity
velocity-rotational-x f
rotational velocity ($$x$$-component)
velocity-rotational-y f
rotational velocity ($$y$$-component)
velocity-rotational-z f
rotational velocity ($$z$$-component)
structure node initialize Keyword Block
The initialization values specified with the structure node initialize command may be optionally modified with the keywords below.
They apply (except where noted with regard to the local keyword), to all of the major keywords of the command: displacement, displacement-rotational, displacement-rotational-x, displacement-rotational-y, displacement-rotational-z, displacement-x, displacement-y, displacement-z, position, position-x, position-y, position-z, ratio-target, velocity, velocity-rotational, velocity-rotational-x, velocity-rotational-y, velocity-rotational-z, velocity-x, velocity-y and velocity-z.
the existing value of the parameter (of all nodes in the range) is set to its current value plus the given value. For example, one can add 0.1 to all node $$x$$-displacements with the command structure node initialize displacement-x 0.1 add.
multiply
the existing value of the parameter (of all nodes in the range) is multiplied by the given value rather than being set to the given value. For example, one can multiply all node $$x$$-displacements by a factor of 1.5 with the command structure node initialize displacement-x 1.5 multiply.
local
specifying the supplied value will initialize the node in local coordinates. This keyword may not be used with position (position, position-x, etc.).
the value installed in each node in the range is $$val_f$$ = $$v$$ + $$xg_x$$ + $$yg_y$$ + $$zg_z$$, where the gradient keyword is given immediately after the the supplied value ($$val$$ here), and ($$x$$, $$y$$, $$z$$) are the components supplied by v, which specifies the reference position of the node. If the multiply keyword is also present, then the given gradient is applied to the multiplier.
|
2022-05-22 23:06:38
|
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|
https://cs.stackexchange.com/questions/100483/why-do-you-need-at-least-lnn-many-comparison-to-sort-a-list
|
# Why do you need at least ln(n!) many comparison to sort a list?
"If every element comparison (testing whether $$a_i \le a_j$$ ) provides at most one bit of information, argue that you need at least on the order of $$\ln(n!)$$ many tests/comparisons to sort the list."
This is a question on my homework at the moment. I don't understand how I'm supposed to go about arguing this as I don't quite understand why it is true. Any pointers in the right direction? Thanks.
• There should be explicit pointers in your course material such as textbook or lecture note. Can you summarize what you had learned just before this homework? Nov 24, 2018 at 1:02
• This question is in reference to what was taught a few lectures back and so I can't recall it as well as I should but we proved the worst case Big Oh time-complexity of merge sort and insertion sort. Our professor talked about the minimal amount of work required to sort a list but I'm a bit lost on that part although I feel as if the answer is related to that. Nov 24, 2018 at 1:11
• @toshko3331 Search for lower bounds on sorting, you should get your answer. Nov 24, 2018 at 1:57
You should model the comparison based sorting problem with decision tree where each node represents a comparison. You should see there are $$n!$$ leaves of such tree each contributes to a possibility of sorted array. If $$h$$ is the height of such tree, then $$2^{h} \geq {n!}$$ follows.
With k decisions, you may be able to reduce the possibilities to $$n! / 2^k$$ possibilities. You need to reduce the possibilities to only one, and for that you need to make at least $$log_2 (n!)$$ decisions.
With fewer than $$log_2 (n!)$$ decisions, there must be at least two permutations where all those decisions would give the same outcome, and since you don't know which of these two permutations you started with, you can't sort both permutations correctly.
|
2022-07-01 02:32:55
|
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|
http://www.scottaaronson.com/blog/?p=1781
|
## Is There Anything Beyond Quantum Computing?
So I’ve written an article about the above question for PBS’s website—a sort of tl;dr version of my 2005 survey paper NP-Complete Problems and Physical Reality, but updated with new material about the simulation of quantum field theories and about AdS/CFT. Go over there, read the article (it’s free), then come back here to talk about it if you like. Thanks so much to Kate Becker for commissioning the article.
In other news, there’s a profile of me at MIT News (called “The Complexonaut”) that some people might find amusing.
Oh, and anyone who thinks the main reason to care about quantum computing is that, if our civilization ever manages to surmount the profound scientific and technological obstacles to building a scalable quantum computer, then that little padlock icon on your web browser would no longer represent ironclad security? Ha ha. Yeah, it turns out that, besides factoring integers, you can also break OpenSSL by (for example) exploiting a memory bug in C. The main reason to care about quantum computing is, and has always been, science.
### 159 Responses to “Is There Anything Beyond Quantum Computing?”
1. rrtucci Says:
So, did P=NP during inflation, as Lloyd proposed?
2. Scott Says:
rrtucci: I hesitate to ask, but … where did he propose such a thing?
Assuming P≠NP “now,” the answer to your question is of course no: if P≠NP is true at all then it’s a timeless mathematical truth. Logically, one could imagine that NP-complete problems were efficiently solvable during inflation (if anyone was around to solve them then 🙂 ) but not afterward, but I’ve never heard of such a speculation or of Seth Lloyd proposing it, nor can I think of a good basis for it. Sure, space might be expanding exponentially, but any one observer has a bounded causal patch and doesn’t get to exploit that fact—in fact, the inflation makes things much worse for such an observer, by inflating away most of the computer before it can return an answer!
3. rrtucci Says:
Lloyd proposed this in his paper about the universe as a quantum computer. He called it the inflationary quantum computer.
4. Scott Says:
rrtucci: Do you mean this paper? I just searched it and couldn’t find anything about inflation or P vs. NP. A link would be appreciated.
5. Mateus Araújo Says:
That was a very pleasant read.
As for myself, I like to hope that quantum gravity will give us some exponential speedup for some algorithms. Not via closed timelike curves which, as you have pointed out, seem to powerful to exist, but via a subtler effect: superposition of metrics. This could give rise to a causal structure that is genuinely different, and yet free of paradoxes.
There has been some exploration of this idea (see, e.g., arXiv:0912.0195), but nothing yet that comes close to the holy grail of exponential speedup.
But hey, one can dream!
6. Jon Lennox Says:
I It’s seee vox.com‘s quoting you for a quantum computing explainer… It’s better than some press accounts, but still sort of meh.
(It’s useful for scaling my “how well are they explaining things I don’t understand” heuristic, I suppose.)
7. Scott Says:
Jon Lennox #6: Had similar thoughts.
On the other hand, I’ve learned over the years that, if I try to calibrate how well journalists explain things I don’t work on by looking at how well they explain quantum computing, then I end up a raving conspiracy nut who doesn’t even believe local traffic reports. 😉 The more charitable view is that QC really is one of the hardest things on earth for non-scientists to get right, because not many can get over the hurdle that “the place you need to be to understand this developing story” is not a lab with anything you can see or touch, but a 2n-dimensional Hilbert space.
8. David Cash Says:
Wearing my security pedant hat here: Heartbleed is not a buffer overflow. It’s actually sort of the opposite.
9. fred Says:
Scott, you wrote
“when computer scientists say “efficiently,” they mean something very specific: that is, that the amount of time and memory required for the computation grows like the size of the task raised to some fixed power, rather than exponentially.”
Now I’m getting a bit confused about memory.
When we talk about the amount of memory required, does it matter whether the memory is made of bits (classical) or qbits (QC)? The “size” is the same regardless? (N bits or N qbits… but N is the input size).
An internal register in a QC is clearly made of qbits and in that sense it can store more information (in QM mode) than a regular classical memory.. it seems “unfair” to equate 8 bits of classical memory with 8 qbits (esp given how much more complicated it is to build 8 qbits rather than 8 bits, but that’s a practical consideration).
Maybe I never thought of the exact definition of a QC, like is there a formal of a Quantum Turing machine?
10. Scott Says:
David Cash #8: Thanks, I fixed the post! Is there a more general name for “the type of security flaw that keeps cropping up over and over and over because C doesn’t check that pointers to an object in memory are in bounds, and it’s nearly impossible for a human programmer to think of every possible way of exploiting that fact, and despite this known problem, people continue to write super-sensitive code in C, rather than in programming languages that make this particular kind of bug impossible”?
11. Scott Says:
fred #9: Yes, there’s a formal definition of quantum Turing machine; it was given by Bernstein and Vazirani in 1993 (but today almost everyone uses uniform families of quantum circuits, which are formally equivalent to QTMs and less cumbersome to work with).
And in an efficient classical algorithm, the number of bits should grow only polynomially with the input size, while in an efficient quantum algorithm, the number of qubits should likewise grow polynomially. In both cases, the number of bits or qubits roughly corresponds to the actual number of particles in the actual physical memory, so that’s why (along with the running time) it’s a relevant quantity to bound. And yes, of course we think you can do somewhat more with n qubits than you can do with n classical bits (given the same amount of time), by subtly exploiting the fact that n qubits take 2n complex amplitudes to describe, and that the amplitudes (unlike classical probabilities) can interfere. That’s why quantum computing is interesting in the first place!
12. Jerry Says:
re: Scott’s Comment #7:
It is the quantum leap from 2^n-dimensional Hilbert space to 3-D Euclidean space and the assertion that QM = QC that remain the hurdles to scale (analogy intended). Many of your blog followers are also scientists who are interested in the science hidden in QM, but you patronize those of us who don’t agree with you.
If, ten years from now, it is demonstrated that QC is a myth, you are unlikely to change your field to medieval architecture. No, you will use that fact to advance computer science and complexity theory in the direction that truth takes us.
13. fred Says:
That “Shakespeare paradox” is a good one.
We can replace Shakespeare writing a play with a search problem, and we go back in time to supply the solution index. We’ve done the search without doing any work.
“Somehow Shakespeare’s plays pop into existence without anyone going to the trouble to write them!”
But the play still has to be a valid “solution” in the sense that Shakespeare has to accept it, the only stable loops are the ones where Shakespeare wouldn’t scream “That’s horse shite! no way I’m putting my name on this!”, i.e. Shakespeare brain acts as a polynomial checker for the play.
But the problem is not about the play popping into existence, the problem is that if we imagine that every play Shakespeare ever wrote has been fed to him there’s an issue – Shakespeare brain itself has to pop into existence: the act of actually writing the play is modifying Shakespeare’s brain in a way that proofing a play doesn’t. So in the end the whole concept of a Shakespeare play would “dissolve”.
The same happens with the search analogy, if you always feed back to answer, then no search algorithm has ever been implemented/designed, the very concept of a search vanishes from CS books!
14. wolfgang Says:
@Scott #4
Could it be that rrtucci fell for his own April Fool’s joke?
qbnets.wordpress.com/2014/03/30/the-inflationary-quantum-computer/
15. Scott Says:
Jerry #12: On the contrary, some might call your comments on my last post patronizing. When you take away the preening puns and irrelevant Jewish asides, what’s left of them is a large ignorance about basic facts of QM—something that, indeed, I’m happy to help people with; I spend much of my life doing that—but then, and this is the part that gets me, a wounded insistence on having your personal opinion about QC being just like bigfoot or the Easter Bunny taken seriously, despite your demonstrated ignorance of freshman facts that even relatively-“serious” QC skeptics understand (“If QM is so fragile as to mandate the No-Cloning rule, why is it so robust as to also enforce the No-Deleting rule?” / “If 2.7 K is too ‘hot’, I have made my point”).
So go reread my book, read the other quantum computing primers linked from the sidebar on the right, learn about all the experiments that have already been done demonstrating the reality of complicated entangled states, wrestle with the difficulty of accounting for the already-known facts without invoking 2n-dimensional Hilbert space, and then even if you still disagree, I’ll be happy to have you participate in discussions on this blog.
16. Ben Mahala Says:
Hey I just read your article and I’m not sure this statement is true:
“At some point, your spaceship will become so energetic that it, too, will collapse into to a black hole.”
You can’t generate a black hole by accelerating an isolated object too much. You have to have a collision where the center of mass energy is high enough and an isolated object doesn’t provide that.
Practically, you would always run into CMB photons, but I don’t think that’s the point you’re trying to make.
I am unsure if Unruh radiation could allow you to get around this constraint. Do you have a source on this?
17. Scott Says:
Ben #16: You raise a good point, and I apologize for not being clearer about it. Yes, I think you’re correct that the “only” reason such a fast-moving spaceship would collapse to a black hole, would be its inevitable collisions with any particles that it hit. For that reason, it would’ve been better to say that simply getting the spaceship up to the requisite speed would already take exponential time, unless you used a form of fuel so dense that the fuel tank would then exceed the Schwarzschild bound and collapse to a black hole.
18. David Cash Says:
@Scott: I think it’s usually called a bounds checking error, but I don’t know if there’s a more specific name for the Heartbleed type of bug.
19. Douglas Knight Says:
Scott, maybe you be a raving conspiracy nut. Yes, if it were just QC, you could conclude that your field happened to be the most difficult to explain, but ask other people how the press covers their fields. They all say the same thing! But local traffic is different. Unlike the rest of the news, people listen to the traffic and the weather for practical reasons and go out and test those predictions.
20. John Sidlesbot Says:
Nicolas Cage is decidable. Suppose further might find the act to the Kählerian state-spaces, optimization problems in the state-space.If we extend this is derives from a hugely in any other beautiful to the Penrose with reconciling of tendonitis and say “model” we believe at all too hard theorems.
Scott and SPINEVOLUTION … nor Turing Machines depart pretty much confusion over a while scientific theories that the “north pole” of the capabilities enable — surely discover it seems too … No stock options, I happen to proving to decide these fundamental physics is that these singularities that Alice comes in.
Witten told me that, for the broadest sense is not just as students who looks to be random, as a radical optimism for students (and moral) imperatives of this balanced gender differences … both authors who are written about lists is whether Pullman and falling in any other … but we can the above social justice will be a flow on the irresponsible mathematical abstractions, the invited me in particular the principles of photonic resources.
21. fred Says:
Btw Scott, your paper is really amazing, both in clarity and breadth. I’ve learned so much since I’ve been following you.
Thank you!
22. Silas Barta Says:
@Scott: I know it’s incidental to your main point, but I was confused by the reference to primality testing scaling with the cube of a number’s digit-length. I thought the fastest deterministic tests were n^4?
Or did you mean that the probabilistic tests use in practice scale as n^3? I couldn’t find a reference to an n^3 primality test.
23. Scott Says:
Silas #22: Sorry, I was talking about the randomized algorithms, which are what everyone has used in practice since the 1970s. Deterministically, I believe the best known runtime is O(n6), due to Lenstra and Pomerance from 2005 (improving the O(n12) of AKS), but it can almost certainly be improved further.
24. fred Says:
“Compared to string theory, loop quantum gravity has one feature that I find attractive as a computer scientist: it
explicitly models spacetime as discrete and combinatorial
on the Planck scale”
One thing I don’t understand about space having a discrete structure:
How to reconcile any such model with the fact that there is no absolute frame of reference in translation and the fact that there is an apparent absolute fixed frame for rotation? It seems that a discrete model would bring us back to the old idea of “aether”.
Is it sufficient to say that space only exists in relation to massive objects (Mach principle)?
25. anon Says:
Scott #10 well, a competent C programmer would use a competent static code analyser . The overhead for using alternative “safer” coding environments than C is sometimes not acceptable just so you can be 100% safe – I mean a handful of isolated security issues over the years doesn’t equate to a broken model.
Running all SSL implementations in the world in Java or .NET for example would slow the internet (a little) and add a large carbon footprint and apparently that’s evil.
fred #24 the Lorentz invariance is thought to break down at the planck scale but holds exactly for observables above this scale
26. Sandro Says:
Is there a more general name for “the type of security flaw that keeps cropping up over and over and over because C doesn’t check that pointers to an object in memory are in bounds, and it’s nearly impossible for a human programmer to think of every possible way of exploiting that fact, and despite this known problem, people continue to write super-sensitive code in C, rather than in programming languages that make this particular kind of bug impossible”?
Insanity.
27. Sandro Says:
anon #25:
Running all SSL implementations in the world in Java or .NET for example would slow the internet (a little) and add a large carbon footprint and apparently that’s evil.
Or you could program them in Ada in which these bugs can’t happen. It’s maybe 5-15% slower than C on average, with all runtime checks enabled.
28. Scott Says:
fred #24: Look, that quote was from the me of 2005! 🙂 Since then, my views have shifted a bit, as I learned that AdS/CFT (which emerged from string theory) might actually come closer than LQG to giving me the thing I really want—namely, a view of reality that makes manifest why the state of any bounded physical system can be seen as a finite collection of qubits, evolving unitarily by the ordinary rules of quantum mechanics.
LQG does give you spacetime “discreteness” at the Planck scale, which I find nice (especially since it wasn’t put in explicitly). But then I was never able to get a clear explanation of how you get dynamics compatible with unitarity (and moreover, LQG pioneer Lee Smolin has advocated trying to derive QM as an approximation to something else, which is not at all the kind of approach I’m looking for). In AdS/CFT, by contrast, unitarity is emphatically upheld, and the CFT side is even well-defined—the “only” problem, then, is that you don’t seem to get any clear picture of “what spacetime looks like at the Planck scale” over on the AdS side.
Anyway, though, regarding your question, I think an important point to understand is that the LQG models don’t involve anything nearly as simple as a lattice / cellular automaton like Conway’s Game of Life. Rather, they involve a superposition over different networks of loops, which superposition is supposed to have the property that it looks rotationally-invariant, Lorentz-invariant, etc. etc. as long as you examine it above the Planck scale (as anon #25 said).
29. Scott Says:
anon #25: Yeah, if you really needed to use C in a super-security-critical application like this one, then at the least, I’d hope you would use static analysis or formal verification tools! On the other hand, when you consider how much code written in higher-level languages is probably run all over the world for Candy Crush, popup ads, etc. etc., it doesn’t seem like writing SSL in such a language would be such an unjustifiable waste of precious computing cycles. 🙂
30. fred Says:
Scott #26, anon #25 Thanks!
Regarding “closed timelike curves”, wouldn’t the ability to send a qubit back in time contradict the no-cloning argument?
(that’s probably the least of our worries)
31. Scott Says:
fred #30: Yes, and yes, it’s the least of our worries.
32. LK Says:
Fascinating article. The solution of hard problems and its limitations by relativistic travel is new to me.
It reminded me of various papers I read about superpositions between physics and complexity theory.
The one that I found most striking is the one by Seth Lloyd (I guess) where he shows that if QM is even slightly non-linear, then a QC can solve NP-complete problems.
Was the result like that or I misunderstood?
Do you know other papers along this line?
Could one turn the argument around and say that since QM is linear, then np-complete problems are not in P and therefore etc..etc..?
This will turn the P=NP question in an experimental verification
about the linearity of QM. Where is the mistake in this reasoning?
Thanks.
LK.
33. fred Says:
About the complexonaut article, it’s funny how you felt left behind because you only discovered coding at 11.
Whereas I guess I was pretty lucky to start programming at 12… in 1982 on a ZX Spectrum (48KB or RAM). It would have been nearly impossible to do it before that.
And having access to a machine was one thing, but without the internet all I had was the default manual, so it wasn’t exactly “coding” (we would also pass around photocopies of articles). Jeez, it took me weeks to figure how to display a spinning cube in correct perspective (I had no clue about projection matrices and all that).
34. Scott Says:
LK #32: If you read my NP-complete Problems and Physical Reality, you’ll find a whole compendium of different zany ideas along Abrams and Lloyd’s lines.
As for “turning the difficulty of NP-complete problems into an experimental question”: well, the obvious issue is that if (as almost all of us expect) QM is exactly linear, then that still doesn’t prove that NP-complete problems are hard, since you’d still need to prove NP⊄BQP, which is a strengthened form of P≠NP! It’s just that QM being nonlinear would imply that NP-complete problems were easy.
Also, just a point of terminology, but again, “P=NP?” is a purely mathematical question by definition. Unfortunately, there’s no generally-accepted catchy abbreviation for the different but related question that we’re talking about, of whether NP-complete problems are feasible in the physical world.
35. LK Says:
Scott #34,
I’ll take a look to your paper.
Thanks for all the other clarifications.
LK.
36. Jason Gross Says:
This might be a bit off-topic, and if it’s too off-topic, I apologize.
Is there anyone studying the dependence of complexity classes on the strength of the mathematical theory you’re working in? The only example that I know of is that that winning hydra game is a decidable problem only if you are working in a theory strong enough to prove the consistency of Peano Arithmetic. (In appropriate mathematical theories, every strategy is a winning one.) Are there any problems that depend on the axiom “ZFC is consistent”?
37. Jerry Says:
Scott #15
If you are as acerbic to me as you are to Stephan Wolfam, I consider it a compliment:
http://qbnets.wordpress.com/2013/04/13/stephen-wolfram-reviews-quantum-computing-since-democritus/
With that stated, I merely disagree with you on the scalability of quantum computers. I very much agree with your comment #2: “…if P≠NP is true at all then it’s a timeless mathematical truth…”. This is a far better foundation to implement dialog.
There is an article in Nature, “Plants perform molecular maths”
http://www.nature.com/news/plants-perform-molecular-maths-1.13251
also discussed on “Gödel’s Lost Letter and P = NP”:
http://rjlipton.wordpress.com/the-gdel-letter/
Putting all of this together: If plants can do some sort of “calculation”, even if it’s only statistics that gets them through the night, maybe there is an argument that self-replicating molecules and accreting matter in the early universe did the same thing. What does this add to the P = NP party?
As far as the “preening puns”, Wolfram detests your “humor”.
As far as “…demonstrated ignorance of freshman facts…”, it seems the only way to rectify that is to buy your book. $35.99 for paperback! I’m Jewish (at least the last time I looked) give me some credit. 38. Scott Says: Jason #36: It’s a good question. First of all, whether a given problem is decidable or undecidable, whether it’s in P or outside P, etc. are questions with definite answers, independent of any formal system—in just the same way that the Twin Primes Conjecture is either true or false (i.e., there either are infinitely many twin primes or there aren’t). Surely you agree that either there is a Turing machine M that halts in such-and-such number of steps on every input x∈{0,1}n or else there isn’t! The part that can depend on the formal system is which such statements are provable. So for example, let me define for you right now a language that’s actually in P, but for which ZFC can’t figure out whether it’s in P or EXP-complete: L = { ⟨x,y,z⟩ : x encodes a Turing machine that halts in at most y steps, and z encodes a proof of 0=1 in ZFC }. If ZFC is consistent then L is the empty language (and hence in P), while if ZFC is inconsistent then L is EXP-complete. So you can’t prove L∈P without proving Consis(ZFC). Now crucially, note that this independence from ZFC is not a property of the language L itself, but only a property of how I described L to you! If I just told you that L was, in fact, the empty language, then of course you could give a ZFC proof that L∈P. For this reason, we see that something like “the subclass of P consisting of all languages that ZFC can prove are in P” doesn’t even make sense: we can only consider the set of all descriptions of languages such that ZFC can prove that the so-described language is in P! Anyway, the one place I know of where this sort of thing was really explored in depth is a 1978 monograph by Juris Hartmanis, called Feasible Computations and Provable Complexity Properties. Moderately-related, you could also try my old survey article Is P vs. NP Formally Independent?. 39. fred Says: #37 Jerry That thing about plants doing arithmetic is pretty overblown – you can replace that “division” with a rate of consumption that is proportional to the quantity of left-over starch once daylight appears. It’s just basic control theory. 40. asdf Says: OpenSSL had already been checked with various static analysis tools, and they didn’t spot Heartbleed: http://blog.regehr.org/archives/1125 Static analysis can only catch certain classes of bugs. The basic problems are C itself, and that OpenSSL is very crufty code. 41. asdf Says: By the way, I saw the PBS article linked from another site, started reading it and got the idea of posting a link here because I figured Scott might be interested. Then I noticed he was the author… 42. TP Says: Fred #24 “there is an apparent absolute fixed frame for rotation?” I was going to start this reply by saying I don’t think there is, however by the end I changed my mind. In special relativity there is the Thomas rotation and Thomas precession whereby observers who do not feel themselves to be rotating will appear rotated differently to different observers moving at different velocites. This effect has no analog in Newtonian physics, it is a purely relativistic effect. Additionally when gravity is added to the picture with general relativity then Thomas precession can be subsumed into the larger precession: de Sitter precession. If I recall correctly I seem to remember Luboš Motl writing something to the effect that rotation of an object can be felt by the local spacetime curvature and the object can also feel itself rotating with respect to this curvature. There is also the Lense-Thirring effect. To the extent that rotation is with respect to spacetime geometry, translation in curved spacetime also moves through varying geometry so there is absolute motion in curved space for translation. Spacetime geometry allows an observer to feel the difference between all types of motion. Also spacetime is dynamic so a particle can’t be at rest therefore the ideas of relative frames and no-absolute frame in special relativity don’t really apply to curved space. 43. TP Says: Thomas rotation makes the orientation of observers look different and Thomas precession makes the rotation rate of a spinning object look different. So in special relativity both rotation and translation are relative. But in general relativity both rotation and translation are absolute with respect to spacetime geometry if not to other observers. 44. Peter Nelson Says: asdf #40 http://article.gmane.org/gmane.os.openbsd.misc/211963 Even if standard static analysis tools wouldn’t have caught the error, leaving the default malloc/free protection in glibc on would have…. Not going to argue with you that the problem is (at least in part) “C itself”. 45. TP Says: Scott #38: “whether it’s in P or outside P, etc. are questions with definite answers, independent of any formal system—in just the same way that the Twin Primes Conjecture is either true or false (i.e., there either are infinitely many twin primes or there aren’t).” Is it known that the Twin Primes Conjecture is independent of the model of arithmetic that is used and has the same answer for other countable but non-standard models of arithmetic. http://en.wikipedia.org/wiki/Non-standard_model_of_arithmetic What about non-standard models of computation if that makes sense? Not non-Turing-machine models of computation in computer science, but models as in a non-standard model of arithmetic sense. 46. TP Says: A non-standard Turing-machine! 47. Scott Says: TP #45: When we speak about the twin prime conjecture, P=NP, and so forth being “true” or “false,” it’s implicit that we mean true or false in the standard model of arithmetic—just like, if I tell you that I have a stomachache, I don’t need to specify as an extra condition that I meant a stomachache in this world, the actual physical world, rather than some fictional world of my imagination. (I’d only have to specify an extra condition if I were talking about the latter.) To put it another way, nonstandard models of arithmetic are best thought of as “artifacts of Gödel’s Theorems”: by the Completeness Theorem, their existence is telling you nothing more or less than the fact that certain statements (again, statements that are either true or false in the standard model) aren’t provable in your favorite formal systems. So, if (hypothetically) it turned out that the twin prime conjecture was unprovable in ZFC, then yes, there would exist a “nonstandard model of arithmetic” that had a largest pair of twin primes. But the existence of that model wouldn’t be telling you anything more than the fact that the twin prime conjecture was unprovable. And in the standard model—the model that we actually care about when we ask the question—the conjecture would still be either true or false (presumably true!); it’s just that we might not be able to prove it. In any case, probably the twin prime conjecture is provable after all (there was huge progress toward it just within the last few years!), in which case this entire discussion wouldn’t even be relevant, since the twin prime conjecture would be true in all models. For more on these themes, you might enjoy chapter 3 of my Quantum Computing Since Democritus book. 48. Scott Says: Jerry #37: My book is actually priced pretty low by the usual standards of Cambridge University Press. And it’s only$20 on Kindle. 😉
49. Jerry Says:
Scott #48
Thanks Scott. You resolved the NP-Easy part of my response to #15.
My questions involving No-Cloning, No-Deleting, and Quantum Fidelity involved the black hole information paradox. When you toss in quantum gravity, unitarity is not sacrosanct. This is what I was hoping to get your perspective on, not a “failure-to-do-my-8.01-homework” spanking.
Is this a Bill O’Reilly-esque book-selling blog?
50. Darrell Burgan Says:
Only a layman’s viewpoint, but from a pure programming standpoint there are a large number of intractable classical problems that would be easily solvable if one had a time machine. I deal with them all the time. Imagine a cache that knows what data needs to be used next!
Seems intuitively clear that if closed timelike curves exist, all kinds of crazy possibilities emerge.
51. Darrell Burgan Says:
Anon #25: not sure I agree that a JVM or analogous approach is always slower than C. JIT compilation can perform optimizations that are impossible in static optimization through the mere fact that the JIT executes at runtime. I think we agree that nothing approaches the speed of hand-tooled assembler code.
As to JVM being safer, that is also itself uncertain. There are an increasing number of JVM exploits these days. Yeah there’s not supposed to be such a thing as a rogue pointer but there are lots of other holes in the cheese.
52. Darrell Burgan Says:
Scott #48: your book just arrived today. Looking forward to a nice read these coming days.
53. Scott Says:
Jerry #49: Well, I’m one of the people who thinks that unitarity most likely is sacrosanct even for black holes—or rather, it seems to me that the idea that unitarity is sacrosanct has led to better, more productive ideas about black holes than the idea of abandoning unitarity. There’s a lot more to say about this topic; check out my previous posts about the “firewall” problem if you’re interested.
54. Jerry Says:
Scott #53:
Thanks Scott. Your Shtetl is not only optimized, it is normalized. The Hawking Radiation Firewall is the answer I was trolling for. I found an excellent summary at:
http://blogs.discovermagazine.com/cosmicvariance/2012/09/27/guest-post-joe-polchinski-on-black-holes-complementarity-and-firewalls/#.UUfAUlfTFq4
Here is an excerpt:
…[]Susskind had nicely laid out a set of postulates, and we were finding that they could not all be true at once. The postulates are (a) Purity: the black hole information is carried out by the Hawking radiation, (b) Effective Field Theory (EFT): semiclassical gravity is valid outside the horizon, and ( c ) No Drama: an observer falling into the black hole sees no high energy particles at the horizon[]…
Perhaps you do not like my posts because my “humor” is so similar to yours. If you prefer that I do not contribute questions, opinions, and factoids, it is your blog and I will comply.
Regard!
55. anon Says:
asdf #40 interesting!
It seems that (as Peter Nelson #44 points out) the OpenSSL programmers implemented their own wrapper for the malloc() and free() calls, apparently due to concerns about inefficient performance on some platforms with the default library implementation. This has had the wonderful effect of crippling the ability of most (all?) static analysers to find bad code like the Heartbleed vulnerability. In fact it’s almost not even a bug rather just bad programming. I’m sure these guys wouldn’t be 100% trustworthy using Java, C#/.NET, Ada or anything else.
However I should point out that I’ve worked in commercial programming environments and seen much more shocking code – it’s certainly not something to blame on the free open source software model itself.
BTW, I thought Scott’s beyond QC article was very interesting but didn’t have anything concrete to add (although I’m 100% convinced closed timelike curves do not exist in Nature – so that part of the discussion is fun for me philosophically but not scientifically). I hope these comments on Heartbleed are not too off topic.
56. Scott Says:
Jerry #54:
Your Shtetl is not only optimized, it is normalized [in reference to my belief in unitarity].
OK, while many of your jokes were lame, that one was decent. 😉
anon #55: No, it’s not off-topic at all; thanks for the insights! It’s been a decade since I wrote any C code, but I definitely remember what a pain all those malloc()’s and free()’s were—I certainly wouldn’t be able to write C code that was secure against bounds-checking attacks, and were I forced to, I would demand some sort of automated tool that provably made that particular type of attack (though not, of course, other types) impossible.
57. Michael Dixon Says:
@#55 @#56
While you are at it, check that your compilers are squeaky clean and sound as well. You probably should go all out and do the formal verification on the assembly or HDL level, though. Those basement-dwelling compiler nerds are NOT to be trusted!
58. William Hird Says:
Hi Scott,
One quick question concerning black holes and information loss, if a lowly little NAND gate can erase information ( loses 1.189 bits with a 2 bit input), why can’t a black hole with a “blazing firewall” also destroy information?
59. Scott Says:
William #58: Well, a completely ideal NAND gate with no side-effects would violate quantum mechanics! The only reason why “NAND gates” can actually be built in reality, consistent with the known reversible laws of physics, is that in practice all gates have dissipation, and the dissipation carries away the information needed to reconstruct the original two input bits, even when the output is a 1.
If black holes are to play by the same reversible, quantum-mechanical rules as everything else in the known universe, then (firewall or no firewall) the infalling information needs to dissipate out of them as well, just like it dissipates out of the NAND gate. And if black holes don’t play by the same rules as everything else—well, OK then, go ahead and create a revolutionary new framework for all of physics that does away with reversibility, explain why your framework appears to uphold reversibility in all non-black-hole situations, and give some evidence for your new framework’s truth!
Fundamental laws of physics (like reversibility) aren’t the sorts of thing that tolerate exceptions: if there is an exception, then the law is not a law, and a deeper law needs to be articulated.
60. quax Says:
William Hird #58, as Scott desribed above, for your NAND example entropy increases, so it’s no mystery where the information goes.
But IMHO this theoretical insight (by then IBM researcher Rolf Landauer), and its recent experimental validation is still extremely cool science.
On the other hand since Hawking radiation is non-thermal, something gotta give.
Hey Scott, since you proposed a celebrity death match for Geordie in the previous thread, how about you against Penrose to settle this particular question 😉
61. William Hird Says:
Scott#59: Not sure what you mean by a “NAND gate with no side effects would violate quantum mechanics”. What do you mean by side effects?
62. Scott Says:
William #61: I mean information that’s physically generated by the operation of the gate, other than the gate’s logical output. If you had an idealized NAND gate that mapped input bits x and y to only the output bit NAND(x,y), “deleting” x and y from the universe (and leaving no record whatsoever of them, not even in the stray radiation given off as heat), then that would obviously violate the unitarity of QM.
But the resolution is extremely simple: it’s that real NAND gates don’t work like that. They do give off heat, and the heat encodes the information about the input bits x and y.
(Note: If you did want to compute NAND in a completely dissipation-free way, you could in principle do it using a Toffoli gate. I.e. you’d map x,y,z to x,y,(z XOR (x NAND y)), which is then reversible by applying the same gate a second time.)
63. William Hird Says:
Scott#62: Thanks for the clarification.
But: “the heat encodes the information about the input bits x and y”, I want to see the machine that can capture the heat signature of the erased bits and identify them for posterity 🙂
64. Rahul Says:
It’s been a decade since I wrote any C code
Scott:
What language do you usually code in now? Or do you rarely code at all? Just curious.
65. Rahul Says:
Quoting from the PBS article:
Now, the faster you run your computer, the more cooling you need—that’s why many supercomputers are cooled using liquid nitrogen.
Off topic but, do many supercomputers these days use liq N2? I worked with some on the Top500 list circa 2009 & don’t recall many doing that.
Just curious.
66. Rahul Says:
Thus, just as today’s scientists no longer need wind tunnels, astrolabes, and other analog computers to simulate classical physics, but instead represent airflow, planetary motions, or whatever else they want as zeroes and ones in their digital computers,
Again, may be a nitpicking observation, but it doesn’t seem fair to mention wind tunnels in the same class as astrolabes. Aren’t a fair bit of components still tested extensively in expensive wind tunnels? e.g. aircraft wings, turbine blades, car bodies etc.
No doubt, CFD has made huge advances but are we at the point yet where wind tunnels are obsolete?
67. A Says:
anon#25: “the Lorentz invariance is thought to break down at the planck scale but holds exactly for observables above this scale”.
This seems like an interesting idea, does anyone have a link to a source? Intuitively one would expect the deviation from Lorentz invariance to follow a smoother curve (so it becomes negligible as one goes away from the Planck scale, but not so that it suddenly becomes zero at some point)
68. Scott Says:
Rahul, I have a request for you: please limit yourself to one question for me on this blog per day. I can’t keep up otherwise with everything you ask.
What language do you usually code in now? Or do you rarely code at all? Just curious.
Today, I usually code in an extremely high-level language called “undergrad.”
69. anon Says:
A #67
ok mr pedant ( 😉 ), what I mean is that Lorentz Invariance is thought to hold exactly above planck scale distances (ie below planck scale energy) but violations below this distance scale would not contradict relativity as it is not possible to define exact observables on which a measurement could be made at such a scale (since the concept of “length” breaks down)
But, as far as I understand, it would certainly be an unexpected result if Lorentz violations were detected close to the planck scale – in fact there is evidence from indirect measurements that invariance does hold even above planck energies.
However I am not an expert in QG, so you can consider my statement as just an opinion.
70. jonas Says:
William Hird #63: you might get to see it. Cryptographers these days are interested in side-channel attacks, which use the imperfections and side effects of computers. I’m not sure whether they do anything with heat yet, but they do derive information from noise and electric fields and stuff like that.
71. Blacksails Says:
Question unrelated to the blog post:
Is it possible that P or NP are not “properly defined” classes? Imagine if nobody had ever defined P, and instead defined some other class Q, which ended up being what we call P along with a little bit more. It would then be possible than “Part of Q”=NP, but only for that little bit extra.
Basically, what would the consequences be if “Part of P”=NP (say, all problems with some particular scaling or greater, but not including “normal” things like n^2, n^3, etc.), or P=”Part of NP”?
72. Darrell Burgan Says:
I’m sure I’ll get some eyes rolling on this, but in my defense the topic of the blog post *is* whether it is possible that nature would permit computing beyond QC. 🙂
It occurred to me that in the realms of string theory there are certainly purely mathematical models that explore what the world would be like if one or more of the higher dimensions were time-like instead of space-like. And if one of these admittedly wild models actually described nature, then couldn’t a second timeline be exploited for computing, such that answers in one timeline appear instantaneously based upon thousands of years of computation in another?
73. William Hird Says:
Jonas#70:
Hi Jonas, yes I am aware of the “side channel attacks”but to decode the kind of thermal residue that Scott was alluding to I think would take some fancy technology, no doubt that “flux capacitors” and “Heisenberg compensators” would somehow have to be part of the circuitry! 🙂
74. Scott Says:
Blacksails #71: There’s been a huge amount of research involving “variants” of P and NP—whether it’s DTIME(nlog(n)) or BPP or AlgP or NC1 or Monadic NP or MA. (You can look all of those up in the Zoo, BTW.) And that can give you lots of “cousins” of the P vs. NP question—almost all of which are open, with a separation conjectured but not proved, just like with the original question. Anyway, until you make it clearer which kinds of variants of P and NP you’re interested in, it’s hard to be more specific.
75. Scott Says:
William Hird: Because of the Second Law of Thermodynamics, it’s been understood since the 1800s that reversibility of the underlying laws need not imply reversibility by any technology that we can imagine in any foreseeable future. So the right way to put the question is not whether we can actually build a machine to reverse the NAND gate or the black hole, but whether we can explain the NAND gate or the black hole without postulating fundamental physical laws that, at any point in time, ever “delete” the state of a particle out of the universe. For the NAND gate, we know the answer to that question is yes. For the black hole, many physicists conjecture that the answer is also yes, and I’m inclined to agree with that conjecture.
76. William Hird Says:
Scott#75:
You are absolutely correct, my responses show my bias towards gadgets, being a retired electronics engineer, you have the correct scientific interpretation.
77. A Says:
anon #69:
Ah that’s really cool, thanks for the opinion and the link : ) Sorry if it came across as pedantic, just think that the interesting stuff is usually in the details, right along with the devil ;).
78. fred Says:
Scott #59
“a completely ideal NAND gate with no side-effects would violate quantum mechanics!”
“[…] real NAND gates don’t work like that. They do give off heat, and the heat encodes the information about the input bits x and y.”
I was looking again into this and was quite surprised to find out that Maxwell Demon type of question were still being explained well into the 50s (Brillouin) and the 70s (Landauer) – and those discussions actually do not involve QM, right? It’s all in terms of thermodynamics, brownian motion, and information theory.
I guess the simplest example of a non-dissipative gate would be an AND gate using billiard balls (ideas from Toffoli) http://tinyurl.com/nsw2zky
It’s clear that no information is lost and you can always distinguish the cases (0,0)->0, (1,0)->0, (0,1)->0 (by looking at the 0-out and 1-out outputs).
79. Jerry Says:
“Ask me anything, but only one thing”. OK.
If the concept of a multiverse is correct (per Susskind), when matter (or anything else for that matter) does “disappear” into a Black Hole’s (Bekenstein-Hawking) singularity in one of many universes but reappears as a “white hole” in another universe, does this resolve the information loss paradox?
BTW: Is, “Today, I usually code in an extremely high-level language called “undergrad.” in P (pun)?
Math, Physics, Algorithms, and (yes, humor) can all be effective tools for teaching and learning.
80. Scott Says:
Jerry #79: Your “resolution” of the information paradox—that information that falls into a black hole reappears in a baby universe spawned by the singularity—is the one actually advocated by Lee Smolin! (Susskind, on the other hand, doesn’t advocate that resolution at all; he believes in parallel universes, but not that kind of parallel universe.)
Personally, I regard it as a possible but extremely strange solution—one that I would only consider if there were compelling evidence from quantum gravity that black hole singularities really do spawn these baby universes, and if their existence could be given some sort of operational meaning in this universe. At present, my understanding is that there’s no good evidence that black hole singularities really work this way; and furthermore, by preventing Poincare recurrences even within a bounded region of space, this scenario seems to violate “the spirit if not the letter” of quantum mechanics. My preference is certainly for the information to reappear in this universe!
81. Scott Says:
fred #78: Yes, you can discuss the Maxwell Demon paradox purely in terms of classical thermodynamics and classical reversible computation! The laws of physics are reversible, and phase-space volume is conserved, already classically, and that’s pretty much all you need to explain both the paradox and its resolution.
82. Jerry Says:
Scott #80
83. Mike Says:
84. Scott Says:
Mike #83: I liked that paper and found the notion of additive universality to be interesting. Of course, what one really wants is a set of “candidate physical laws” (e.g. a cellular automaton) for which additive universality can be proved to hold, rather than just constructing a model for which it holds almost by definition. But it’s a nice start.
85. matt Says:
Scott, you write “So the right way to put the question is not whether we can actually build a machine to reverse the NAND gate or the black hole, but whether we can explain the NAND gate or the black hole without postulating fundamental physical laws that, at any point in time, ever “delete” the state of a particle out of the universe. For the NAND gate, we know the answer to that question is yes.”
There are indeed several basic ways in which we “know” the answer is yes classically, but it is quite subtle IMO to specify in which way the quantum situation is less satisfactory than the classical one. I’ll give some specific examples, but overall I’d say there’s still a lot to understand classically, in the same way that pseudo-random number generators are still not fully understood in computer science. For a computer science analogue, giving a general proof of thermalization for a large variety of classical systems would probably be on par with proving P=BPP; actually, my guess is it would be harder as the standard arguments for thermalization roughly rely on assuming that certain events in a deterministic process can be treated as if they were random so they almost assume that good PRGs exist.
For example, there is a line of research that dates back to Boltzmann, in which he shows that irreversible dynamics can emerge from reversible microscopic laws. However, the original derivation makes an assumption originally called “molecular chaos” in which one assumes that pairs of particles that scatter off each other are drawn independently from the single particle distribution, giving the Boltzmann equation. This does give irreversible dynamics, but requires an assumption. Under similar assumptions, one can argue that irreversible quantum dynamics can emerge. So, perhaps we would like to better justify this assumption.
There is some rigorous work by Lebowitz and collaborators showing thermalization for certain initial conditions for specific systems. This is extremely elegant work, but currently limited in which systems it can be applied to. Conversely, there are some simple quantum systems (like free fermions) in which one can (much more straightforwardly) derive thermalization for certain initial conditions to a generalized Gibbs ensemble. I’d say that currently the knowledge of the quantum setting is much less satisfactory here, but maybe there is no sharp qualitative difference in which we can say that classically this general problem is understood at the level of rigorous math and quantum mechanically it is not.
There are also numerical studies. Some of these numerical studies were in fact controversial classically, where certain systems were thought not to thermalize but were later learned to thermalize at extremely long time. The quantum numerics are much worse of course, but thermalization can be seen in some of those numerics (but not all….)
A final interesting point is that we know from numerical studies using Monte Carlo on classical systems that good PRGs really are needed. There are some famous cases where a poor choices of PRG led to inaccurate results in classical Monte Carlo, even though the PRG was considered good at the time. So, the relation between thermalization and pseudorandomness is subtle.
86. fred Says:
Scott #84
Considering the number of papers referencing it, it’s too bad John Conway named his cellular automaton thing “Game of Life” and not “Pokemon Mystery Dungeon: Explorers of Time and Darkness”.
87. David Brown Says:
“… there either are infinitely many twin primes or there aren’t …” Suppose Peano Arithmetic is logically inconsistent. Is the statement about twin primes then true?
88. Scott Says:
David #87: Good question. My answer is, absolutely! In the absurdly-unlikely event that PA was found to be inconsistent, we would need to create new first-order axioms for arithmetic. In other words, there would indeed be a crisis for the formal language that we use to talk about the positive integers. But the positive integers themselves would be serenely unaffected by all the commotion: they would still “exist” (in whatever sense they’d “existed” before), and still either have infinitely many twin primes or not have them. And if expressing this view makes me a Platonist, then so be it (though as I’ve said before, I prefer the term “anti-anti-Platonist”).
89. wolfgang Says:
@Scott
>> the positive integers themselves would be serenely unaffected by all the commotion: they would still “exist”
So you really are a hardcore Platonist.
I think it is only fair to point out that there are other philosophies, as listed e.g. here.
90. Scott Says:
wolfgang #90: No, I’m a softcore Platonist. If I were hardcore, I wouldn’t have put scare quotes around the word “exist.” 🙂
91. Dani Phye Says:
“In my opinion, the crucial experiment (which has not yet been done) would be to compare the adiabatic algorithm head-on against simulated annealing and other classical heuristics.”
More recently, have any experiments like this been done?
92. wolfgang Says:
Well, there is still the question what is “exists”? – as I learned from this interview.
93. Jerry Says:
Scott #88:
“God created the integers, all the rest is the work of man.” -Leopold Kronecker
See: “God Created The Integers: The Mathematical Breakthroughs that Changed History” by Stephen Hawking
http://www.amazon.com/God-Created-The-Integers-Breakthroughs/dp/0762430044
I also take the Platonist view, but Scott’s term “anti-anti-Platonist” sounds a bit mathagnostic; similar to an anti-positron, which is not an electron (it is a right-chiral electron that does not interact with the w-boson).
I view Hilbert space as a mathematical tool, but at the end of the day it is nice to kick our shoes off in R^3.
94. Charles Says:
Zookeeper Scott, I know this is off-topic, but can you tell me if $$\exists\mathbb{R}$$ (the existential theory of the reals) is in the Complexity Zoo? I can’t find it, but maybe it’s just under some other name. It fits in somewhere between NP and PSPACE (I’d like to know more, hence looking in the Zoo…).
95. Dezakin Says:
Scott #88
“In the absurdly-unlikely event that PA was found to be inconsistent, we would need to create new first-order axioms for arithmetic. In other words, there would indeed be a crisis for the formal language that we use to talk about the positive integers. ”
In the unlikely event that PA was found to be inconsistent, we would need to create new first order axioms for set theory. PA was proven consistent by Gentzen using concepts that are capable of being embedded into ZFC. The foundations would fall apart with at least as big of a crash as with Russell’s paradox.
96. Sniffnoy Says:
Dezakin: This is a true statement, but it seems to be mostly irrelevant.
That is to say, in my experience, the general feeling among people who study such things seems to be, if ZFC turns out to be inconsistent, then, well, that would be very surprising, and it would be a serious problem, but it would be a recoverable problem, because we could switch to a weaker set theory and still have pretty much all of ordinary mathematics; it would largely just be the set theorists who would have to unlearn what they know. After all, do we really have a good intuition for what should be true about enormous transfinite sets? A number of people have complained that the axioms of ZFC are too strong, and, well, maybe they’re right. Your Russell’s paradox comparison is instructive; sure, we ended up needing new foundations, but most of math outside of set theory was not affected.
By contrast, if PA were found to be inconsistent, that would be truly disastrous, and it’s not at all clear how one could recover from such a thing. PA is a collection of basic statements about natural numbers that really, really, shouldn’t be false. What can you even do if PA is inconsistent? You can’t just go constructive and fall back to Heyting arithmetic; if PA is inconsistent then so is Heyting arithmetic. The obvious thing to do is to weaken the induction schema, of course, and this works perfeclty well if you’re just trying to write down a theory of the natural numbers — but we don’t just want that; we want our theory of the natural numbers to interface with the rest of mathematics. Which means that our new set theory (which of course we’ll need if PA turns out inconsistent) will have to have limitations that don’t allow it to prove the full induction schema, but only the limited subset we choose. And executing that may not be so easy.
So, basically, your comment to me reads as basically saying “If this complete and utter disaster occurs, it will also entail this much smaller and maybe handleable disaster!” (“If the moon crashes into the earth, there won’t be any more tides!”) Yes, it’s true, but it’s probably not what you should be focusing on.
(Not to mention, while Gentzen showed ZFC proves Con(PA), you don’t even need that to see that an inconsistency in PA means you’re going to need a new set theory, since ZFC proves all the actual axioms of PA (appropriately translated), and so the consistency of ZFC implies the consistency of PA. Which is weaker than ZFC proving the consistency of PA, but still enough for our purposes here.)
97. asdf Says:
https://www.simonsfoundation.org/quanta/20140416-times-arrow-traced-to-quantum-source/
Is this something new? I thought the concept that time’s arrow emerged from decoherence had been around for a while.
98. TheOnion Says:
asdf, thank you for calling to our attention this impressive new talent, Natalie Wolchover
99. Scott Says:
Charles #94: (gasp) sorry!! The “existential theory of reals” complexity class seems to be completely missing from the Zoo. You or anyone else should feel free to add it.
100. Scott Says:
asdf #97: In general, the idea that the arrow of time is related to decoherence is a very old one—Everett had the idea in the 1950s, and the founders of QM even arguably had it in the 20s and 30s. And it’s really just a quantum gloss on the thermodynamic arrow of time, which goes back to Boltzmann in the late 19th century (and in many ways, QM changes the story surprisingly little). There’s also a long history of people rediscovering the decoherence/entanglement/arrow-of-time connection, or re-expressing it in different words, and treating it as new. Anyway, the new technical content in the papers Wolchover is talking about appears to be to rigorously derive the equilibration of interacting quantum systems in certain contexts, and to compute explicit upper bounds on the equilibration time.
101. Serge Says:
Asking whether there’s anything beyond quantum computing, that amounts to asking whether there’s anything beyond quantum mechanics, right? So maybe you should ask your friend Luboš about string theory… 🙂
The Heartbleed bug is yet another illustration of the fact that efficiency is always obtained at the expense of accuracy. The developers in OpenSSL will probably consider using a more evolved language – one that manages memory more safely. But at the same time, their programs will get a tiny bit slower. This phenomenon will also be at work when we ultimately have those quantum computers at hand. I’m not saying “scalable” because I don’t know what that means. Such a concept is as difficult to define as is “feasible” or “executable”. However, since quantum computers can compute faster, it will be all the more tedious to ensure the correctness of their outputs, whether at the software or hardware level.
102. Scott Says:
Serge #101: Well, it’s conceivable that Nature could let us do something beyond BQP, even if quantum mechanics is exactly true (as it is in string theory). For example, that could happen if some aspect of the AdS/CFT correspondence or of holography allowed us to apply a “radically nonlocal” unitary transformation in polynomial time, or if the universe had an initial state that was extremely hard to prepare (bumping us up from BQP to BQP/qpoly). However, I completely agree in regarding these possibilities as extremely unlikely—just as unlikely, I’d say, as Gil Kalai’s “dual” possibility, that Nature would let us do less than BQP even though quantum mechanics was exactly true! 🙂
In comparing Heartbleed to hypothetical bugs in a quantum computer, I feel like you’re conflating two extremely different issues. As a general rule, it’s about a trillion times easier to write a correct program—whether classical or quantum!—when the program’s only purpose is to solve some fixed, well-defined math problem, rather than interfacing with a wide array of human users in a way that’s secure against any of those users who might be malicious and exploit vulnerabilities in the code! And there’s no advantage to using quantum computers for the latter purpose: we can continue to use classical computers for that, even as we switch to quantum computers for those mathematical problems for which QCs happen to provide a speedup.
103. Michael Brazier Says:
Regarding the black hole information paradox: isn’t it true that measurement of an entangled quantum particle destroys information, in that it breaks the correlations of the measured particle with the particles it’s entangled with?
104. David Kagan Says:
Michael Brazier #103: Information is not lost, it just moves somewhere else. When an entangled particle’s state is measured then information that was contained in the state of the entangled pair does indeed leak out, but it is preserved in the bigger system that includes the measurement apparatus (and perhaps some portion of the environment it sits in if it is not totally isolated).
105. Scott Says:
Michael #103: Indeed, you could argue that any quantum measurement “destroys information” (namely, all the information that was originally in the quantum state, besides the measurement outcome)! There’s nothing specific to entangled particles here.
However, according to the “Church of the Larger Hilbert Space” / Many-Worlds perspective, even a measurement is “really” just a unitary transformation U that entangles you and your environment with the quantum system being measured. So, such a thing could in principle be reversed, by applying U-1 to all the atoms of your brain, the air molecules and radiation in the room, etc. etc. So, no information was “fundamentally” destroyed. Sure, some information was destroyed “in practice,” but that’s hardly different from an egg being scrambled, a book being burned, or any other classical instance of the Second Law of Thermodynamics.
106. Luke G Says:
“The Heartbleed bug is yet another illustration of the fact that efficiency is always obtained at the expense of accuracy.”
I’d disagree with that assertion. Certainly there exists an efficient frontier of program speed versus difficulty of correct coding. But C is nowhere near that efficient frontier; I’d say it’s particularly far from it. I’m a professional programmer, and many times I’ve witnessed huge productivity differences in languages and frameworks: well-designed stuff can be more efficient for both the CPU and the programmer! For example, I believe that a modern C++ implementation of OpenSSL would be FASTER than the C version and less prone to bugs (for the same programming effort), owing to the better standard libraries and resource management techniques available in C++.
107. Igor Makov Says:
Apparently, one Oprah Winfrey has been an adherent of the “Church of the Larger Hilbert Space”: There’s no such thing as failure. Failure is simply the universe trying to move you in the right direction.
(Sorry, I could not help it 🙂
108. Michael Brazier Says:
Mm. Many-Worlds perspectives face a problem, because measurement prefers pure states to mixed ones.
The possible results of a measurement form a basis for the Hilbert space of the measured particle. But there’s no mathematical reason to prefer that specific basis over any other. With the spin-1/2 particle case, for instance, |spin up> and |spin down> is the basis we normally use, but mathematically |spin up + spin down> and |spin up – spin down> would make just as much sense. We don’t use the latter basis because we never see states like |spin up + spin down> when we measure a physical particle.
Since in Many-Worlds perspectives the larger Hilbert space is all there is, how does one account for the apparently special role of the pure states basis in a measurement?
109. Scott Says:
Michael #108: You’re talking about what’s called the “preferred-basis problem.” The usual answer is that the measurement basis is not specified a-priori but instead picked out dynamically, by the process of decoherence. In other words, if you just follow unitary evolution, letting the Schrödinger equation do its thing, you’ll find that entanglement repeatedly splits the wavefunction into branches that don’t interact with each other and that are “forever separated” for all practical purposes. In some of those branches, it will look like a spin measurement was made in the X direction, in others, it will look like a measurement was made in the Z direction, etc., just depending on the details of the measurement apparatus. I stress that this is not just a speculation or hope: you can work out examples in detail and see that this is exactly what happens.
I do think there are serious objections to be leveled against MWI, and I’ve leveled some myself. But those objections take place at a different level: e.g., what do we even mean, empirically, in ascribing “reality” to the other Everett branches? Is the notion of “the quantum state of the entire universe” even useful? Could you, personally, test the truth of MWI by putting your own consciousness into coherent superposition, and then recohering it? Or is irreversible decoherence (and hence, in-principle MWI untestability) a necessary component of consciousness? What is it that accepts the invitation of the formalism to “impose” the Born rule on the decoherent branches?
So yes, you can ask all those questions and more, but I don’t think you can fault MWI for overlooking some simple technical point. At a technical level, MWI is what the math wants!
110. wolfgang Says:
@Scott #109
The decoherence argument to solve the preferred basis problem suffers from one issue imho: Where does the macroscopic measurement device (sitting in a classical almost flat space time) come from?
The calculations you refer to usually simply assume their existence … but their existence means that you have selected one specific branch (or collection of branches) of the mwi wavefunction already.
111. wolfgang Says:
I should mention that Kent and Dowker analyzed the issue I refer to and a brief but good summary is here:
http://physics.stackexchange.com/questions/65177/is-the-preferred-basis-problem-solved
112. Mike Says:
Scott@109,
” . . . what do we even mean, empirically, in ascribing “reality” to the other Everett branches?”
Better to sometimes employ a rationalist (rather than a strictly empiricist) view, where reason is sometimes considered to be good evidence for the truth or falsity of some propositions. 😉 Nevertheless, assuming that each branch of the wave function is as “real” as any other seems no more troubling or difficult than the reverse.
“Is the notion of “the quantum state of the entire universe” even useful?”
Well, I guess that depends on what you mean by useful, but some folks think that asking “[w]hat is the quantum state of the universe?” is the central question of quantum cosmology! http://arxiv.org/abs/gr-qc/0209046
“Could you, personally, test the truth of MWI by putting your own consciousness into coherent superposition, and then recohering it?
OK, this would be hard, but there are proposals to try and achieve this using, for example, an AGI device. See generally for a discussing of this issue:
http://plato.stanford.edu/entries/qm-manyworlds/#5
“Or is irreversible decoherence (and hence, in-principle MWI untestability) a necessary component of consciousness?”
Perhaps with meat computers 😉 but I’m curious if you think this would hold true with regard to an AGI device?
“What is it that accepts the invitation of the formalism to “impose” the Born rule on the decoherent branches?”
The way I see it, you’ve got two choices: either adopt a “collapse” model (go ahead I dare you 😉 ) or accept that the born rule or some variant will always in a sense be “imposed” because quantum theory (without collapse) has no probabailites, being deterministic. Here is a good overview of the various arguments surrounding the issue:
http://plato.stanford.edu/entries/qm-manyworlds/#4
“At a technical level, MWI is what the math wants!”
I agree!! 😉
113. Scott Says:
wolfgang #110: If you wanted to know where the measurement device came from, then of course you’d need to push the story back further—telling a story of Schrödinger evolution generating entanglement and thereby giving rise to decoherent branches of the wavefunction in which one could see the formation of stars, supernova explosions, the condensation of heavy elements into planets, the evolution of life, and finally the building of spin measurement apparatuses. While I’ve obviously left many details unspecified, 🙂 I don’t know of any good argument that this entire story couldn’t be told in the language of decohering branches of a universal wavefunction, if that’s what you wanted to do. And crucially, if it can’t be, then that strikes me as equally a problem for any account of quantum mechanics, not just for MWI.
114. Jerry Says:
Scott #105 & 109:
A simple Friday question: If you write your name on a piece of paper and burn it, where does the information go? How can it ever be retrieved? If “irreversible decoherence [is] a necessary component of consciousness”, how can the “pieces” ever be put back together in a way that is consistent with the 2nd law of thermo?
115. wolfgang Says:
>> I don’t know of any good argument that this entire story couldn’t be told
Read the comment from Jesse Riedel at the link I provided, including the Kent/Dowker paper (arxiv.org/abs/gr-qc/9412067), who provide such an argument.
But I assume you already read it and did not find it convincing?
>> equally a problem for any account of quantum mechanics
I think of mwi as a programming language without ‘garbage collection’, (no branch of the universal wavefunction gets removed by the Copenhagen reduction).
Are all programming languages (interpretations) in the end equivalent? Yes, but some are much harder to use and I would argue that mwi is unnecessarily hard to use even for simple cases 😎
116. Scott Says:
wolfgang #115: The paper by Dowker and Kent that you referenced is critiquing the consistent-histories approach, which (while I’ve never fully understood it) seems to involve some additional baggage over and above bare MWI. It’s long, but I’ll read it when and if I get a chance.
117. Scott Says:
Jerry #114:
If you write your name on a piece of paper and burn it, where does the information go? How can it ever be retrieved?
The information goes into the smoke, ash, and other byproducts. That’s just standard, 19th-century physics, not anything fancy or new. In practice, it’s nearly impossible to retrieve the information, but only for more-or-less the same sort of reason why it’s hard to reconstruct a puzzle (though not impossible!) after I’ve shaken up all the pieces. In the case of the burned paper, the puzzle involves ~1022 microscopic pieces rather than just a few hundred macroscopic ones (and many of the “pieces” consist of radiation that’s since flown away!), so the problem is many, many orders of magnitude harder.
118. fred Says:
I’ve tried hard but I never got that whole “arrow of time” business. I don’t even see what the problem is…
1) time has no preferred direction, but systems evolve based on their initial conditions. i.e. it’s the initial conditions that locally determine what we call the arrow of time.
Our universe seems to have an arrow because the big bang was such a concentrated initial state and it’s “dragging” along everything in it with it. But it’s not clear whether it always has to be the case, i.e. we could imagine universes/systems that are prepared in a less biased way so that different pockets can seemingly evolve in different time directions from one another.
The idea of entropy captures all this, but it’s a concept based on a macro representation of possible states, e.g. there are way many more configurations of the air in this room corresponding to a uniform density compared to a configuration where all the molecules are bundled together tightly in one corner (b)… but every actual configuration where the air density is average is just in itself as rare as (b). It’s like saying that you’re more likely to observe a 6 with two dices (1+5, 2+4, 3+3) than to observe a 2 (1+1), so a “double dice” system will more naturally go from a 2 to a 6 (breaking the egg) rather than the other way around (putting the egg back together), hence there is a time arrow embedded in it.
2) we get biased by our own sense of the passing of time, which is subjective. We perceive it because of the way we construct memories (i.e. the more memories the further away we are from our system’s initial conditions). But it’s all a big space/time block extending and existing instantaneously in every directions.
But it’s likely that things do get more interesting with QM since in that context the notion of “indistinguishably” is so central. But given all the difficulties about what is a measurement, what is a system, …
119. Scott Says:
fred #118: Yes, I think the modern version of the arrow-of-time problem is simply, “why did the universe have such a low-entropy initial state?” Not surprisingly, opinions differ as to whether this is a real problem at all, and what sorts of answers to it would be satisfactory.
120. Scott Says:
wolfgang #115: OK, I just read Jess Riedel’s comment. I think Jess is absolutely right that there’s a formal circularity in the consistent-histories arguments typically offered by people like Gell-Mann and Hartle. Namely, these arguments use the assumption of “quasi-classical histories” to define observers, and then they use observers to define the quasi-classical histories. (Precisely because of such circularities, formal arguments about decoherence have never made me that much more confident in it than I’d been before — but I was already pretty confident!)
However, I would also say that what Riedel points out strikes me as a benign circularity—analogous to what Google PageRank does, in defining an “important website” as a site linked to by lots of other important websites. That is, yes, the definition might not make analytic philosophers happy, but the apparent circularity in it can be “unraveled” by giving an appropriate algorithm. In the case of Google PageRank, the circularity is unraveled by constructing the link graph of the web and then finding its principal eigenvectors. In the case of decoherence, there seems to me to be very little doubt that, given the actual evolution of the wavefunction of a universe like ours, you could write a computer program that would do an extremely good job at picking out the “decoherent branches.” Yes, there could be different ways to do that (and I’m not about to discuss how to do it in the space of a blog comment…), and yes, the different ways could give different results in some edge cases, but at least for “realistic” macroscopic situations, it’s very hard for me to imagine how the different ways could actually disagree in practice. I’d need to see an example where that happened before I acknowledged it as a serious possibility.
121. wolfgang Says:
>> given the actual evolution of the wavefunction of a universe like ours
But I thought this is the problem – the universal wavefunction must continue many universes which are not at all like ours (in fact “freak branches” are the overwhelming majority, which leads to another debate about Born probabilities).
Once you reduce the debate to a “universe like ours”, you are reducing the universal wavefunction – then why not go all the way and use Copenhagen?
122. Jerry Says:
Scott #117
I’m well on board with the 19th century physics aspects. You could (theoretically) tear a piece of paper into 10^22 pieces, throw them into the wind and you would be unlikely to retrieve any info written on it. What about the information at the quantum level? If information at a B.H. event horizon doesn’t just disappear but escapes as Hawking radiation, what about information that we do not have the technology or time to retrieve? Does the info appear as heat (entropy)? The ash, smoke, etc. would be in a different “state” if the original paper had been blank as opposed to having information on it.
123. Scott Says:
Jerry #122: Yes, what you write is exactly what modern physics says happens.
124. Scott Says:
wolfgang #121: Sorry, I meant a universe with a hot Big Bang and a Standard Model Hamiltonian like ours (I’m not attempting to dig any deeper than that…). At least if you measure by the Born probabilities and not in some other way, the overwhelming majority of such universes will look more-or-less like our universe: they’ll have galaxies, stars, planets, etc, obeying the same laws of physics that are familiar to us. Of course it might be that only a small fraction of the branches have intelligent life, and only a small fraction of those have humans, and only a small fraction of those have us, specifically, but those are all implications that MWI proponents enthusiastically embrace! I don’t see how you can criticize MWI on that ground; it seems like question-begging to define any universe where things didn’t turn out just like they did in our universe to be a “freak universe.”
125. wolfgang Says:
>> I meant a universe with a hot Big Bang … if you measure by the Born probabilities …
Yes, if you *assume* a classical background, the existence of macroscopic observers etc. and the Born probabilities then the interpretation problem goes away.
But I thought the whole point of mwi is to *derive* those …
What Jess Riedel et al. are pointing out (if I understand correctly) is that such a *derivation* requires additional assumptions beyond the unitary Schroedinger evolution.
126. Serge Says:
Luke G #106: Then it will be that my own theory has bugs… and that I should have spent more time in thinking it over. Efficiency versus accuracy, as always… 🙂
One way of correcting it is to take into account the time that computer scientists took to invent the C++ language, the right frameworks, the faster computers, the larger drives that would host the new software, etc… Indeed, computer science has evolved significantly since the 1970’s. Now, getting back to my initial comparison, let’s hope the theoretical amount of time required for building a functional quantum computer isn’t infinite…
127. fred Says:
Scott #123
On one hand I hear that all the fundamental physical laws are reversible, so you can’t ever hope to destroy information since everything contains the trace of whatever happened before, and if you were to reverse the time arrow, the past would seem to be caused by the future (indistinguishable at the atomic level) – so God could press rewind/fast forward all he wants on his “space/time continuum” VCR, we would never notice and the film would always be the same.
But on the other hand, QM injects randomness in the universe (only the evolution of the amplitudes is deterministic), so how come this randomness doesn’t destroy information to some degree? Is it because pure randomness carries no information? It seems that QM randomness prevents us from predicting the future but not from inferring from the past. QM muddies the reversibility principle – whenever God himself his pressing “rewind” then “play” on his VCR, the film of the world would be different each time (maybe the movie even looks different in reverse)… Unless he’s watching all the films in parallel with MW?
128. Jerry Says:
Scott 123:
Many thanks, Scott! See, I do know my 19th century physics(and some 20th and 21st). Walter Lewin would be very proud of me and would draw a long dotted line across his blackboard. Have a nice weekend.
129. Scott Says:
wolfgang #125: OK, maybe we don’t actually disagree! I agree that the frequent claims to “derive” the Born rule from unitary evolution alone are overblown, and I’ve said that before on this blog. You can’t get blood from a stone, and you can’t get objective probabilities from a deterministic evolution law without any further assumptions. What one can say, I think, is that the unitary evolution law very strongly invites you to tack on the Born rule: the Born rule just fits unitary evolution like a glove (if they were on a dating website for mathematical concepts, they’d be matched by their shared passion for the 2-norm), whereas there’s no other probability rule that similarly fits (and one can prove like 20 different theorems formalizing that intuition). But yes, saying that |ψ|2 gives you a probability distribution over subjective experiences is an additional commitment you need to make to connect QM to experience, over and above a belief in unitary evolution. You (and Riedel?) are right about that.
On the other hand, I don’t agree that if you can’t “derive” the Born rule from it, then there’s nothing to recommend MWI. An MWI proponent could say: “look, we have the only account of the evolution of the state of the universe that fits the known laws of physics, without invoking a mysterious ‘collapse’ that happens at unspecified times! yes, we might not fully understood consciousness, or observerhood, or the emergence of probabilities, but why should we let that impede our understanding of physics? if the math seems to be militating so firmly for unitary evolution holding always and everywhere, without exception, then why shouldn’t we just go with that, and treat alll the observer stuff as our problem rather than Nature’s problem?”
130. wolfgang Says:
@Scott #129
So what are the Born probabilities actually about?
In “Copenhagen” I would say the probability that I experience M1 or M2. This is straightforward to understand.
In “mwi + patched on Born” it would mean the probability that I find myself in the world W1 vs the branch W2. This is not so easy to understand (for me);
If you complain about the ‘collapse’ in Copenhagen, then I can point out that this “finding myself” follows an unexplained mechanism too.
I would also point out that the unitary evolution of the wavefunction, which depends on a time parameter t, is easy to understand in Copenhagen ( t is associated with the classical clock I carry around with me), but not so easy to understand in mwi.
How do you get (classical) clocks without reducing the universal wavefunction to those branches which contain (classical) clocks?
131. Scott Says:
fred #127: From the MWI perspective, even quantum measurements are reversible in principle, because measurements never “really” happen: they’re just language used to describe unitary evolutions that entangle us with the quantum systems we’re measuring. Or to put it in your terms: yes, God is watching all the branches in parallel. And that being so, for Him to “rewind” the tape is as easy as changing the unitary the controls the branching process from U to U-1.
Anyway, it occurs to me that I should state things more carefully. Here’s what I think is true: from Galileo to the present, no source of irreversibility—or even a hint of one—has ever been found in the microscopic laws of physics. Rather, all irreversibility that we know about seems to be tied up with decoherence, the Second Law of Thermodynamics, and stuff like that.
This whole discussion started with the black hole information problem. There, the relevant point is that, if you want black holes to really, actually convert pure states into mixed states (as Hawking’s semiclassical calculation suggested), then you’d need irreversibility in the fundamental laws, rather than “just” thermodynamic irreversibility. That’s the part that many people (correctly, I think) regarded as suspicious, and these days I’d say that ideas like AdS/CFT have cast severe doubt on it.
132. wolfgang Says:
@wolfgang #130 😎
>> classical clocks
Actually, we can turn this into an interesting homework problem for mwi proponents: Assume that a measurement device is configured so that for outcome M1 a rocket of mass m is fired into outer space and for M2 nothing special happens.
In other words, for |M1> the mass of the Earth will be reduce from M to M – m , while for |M2> the mass remains M. Therefore clocks on the surface of the Earth will tick slightly different, according to general relativity.
This is not a problem for Copenhagen, since either M1 or M2 happens. But how does mwi handle this case?
Does the unitary evolution of the universal wavefunction use clock time t1 or t2 or a combination of both?
133. Scott Says:
wolfgang: All your questions about MWI are good ones! The irony is that I’ve often been on the opposite side of this, asking variants of the same questions you’re asking to the MWI true-believers.
On the other hand, I think intellectual honesty compels one to acknowledge the severe problems on the Copenhagen side of the ledger. Indeed, one could imagine an MWI proponent gleefully asking you: “so, you believe that wavefunctions evolve by the Schrödinger equation, except that sometimes—when they get too complicated or something—they suddenly and violently ‘collapse’? Oh please, tell me more about this ‘collapse’ law. Do you have to be conscious to collapse stuff? Can a frog or a robot collapse wavefunctions? At what point does the collapse happen: the optic nerve? the visual cortex? the soul? Or does it just happen whenever you, like, entangle more than some special number of atoms? What is the magic number, then?” (To get the full effect, you need to imagine the MWIers laughing hysterically as they ask these things.)
134. wolfgang Says:
@Scott #133
I think the Copenhagen interpretation ultimately works best in combination with solipsism:
The reduction of the wave function happens when *I* experience something 😎
I guess this is why “shut up and calculate” is frequently the advice given to students …
135. James Gallagher Says:
Jesus, (RIP)
why can’t you guys just maybe think that Nature does all the collapsing and you just get to observe it?
136. Michael Brazier Says:
Scott@133: The reply to the imaginary MWI proponent is simple: “I need only point out that, to date, nobody has ever seen a quantum particle in a superposition. If unitary evolution were indeed the whole story, we would have actual cases of unquestionably conscious observers being placed in a mixed state for a noticeable time and recohering afterwards – in fact it would be routine and unremarkable. In fact nothing of the sort has ever occurred; therefore there is almost certainly more to the story than unitary evolution. What that might be I cannot at present say, but that’s no reason to deny what’s before our eyes. Also, stop giggling, you look like an idiot.”
IOW, the preferred-basis problem isn’t a simple technical matter that can be resolved by formal calculation. It’s a problem on the same level as the ones that give you qualms about MWI. Indeed, as the basic question is why we have to introduce the Born rule to get testable predictions out of the Schrodinger equation, the preferred-basis problem is a technical restatement of your first objection to the MWI proponents.
137. Mitchell Porter Says:
@Scott #133:
‘one could imagine an MWI proponent gleefully asking you: “… What is the magic number, then?” (To get the full effect, you need to imagine the MWIers laughing hysterically as they ask these things.)’
Then they would be utter hypocrites, since they themselves are unable to give coherent answers regarding how many worlds there are, or exactly when it is that one world becomes two, or really any such details.
138. Audun Says:
Re Scott #88 (anti-anti Platonist)
Your emphasis on double negation being different from no negation would seem to put you in the intuitionist camp 😉
139. Scott Says:
Michael #136:
If unitary evolution were indeed the whole story, we would have actual cases of unquestionably conscious observers being placed in a mixed state for a noticeable time and recohering afterwards – in fact it would be routine and unremarkable.
Sorry, that part of your response is just factually wrong. Decoherence (or ultimately, the low entropy of our universe’s initial state) explains perfectly well why we don’t see such things on the scale of everyday life. (Indeed, assuming a finite-dimensional Hilbert space, “macroscopic recoherences” shouldn’t start happening until the universe reaches thermal equilibrium, and there ceases to be any interesting evolution anyway. And in an infinite-dimensional Hilbert space, macroscopic recoherences need never happen.)
140. Scott Says:
James #135:
why can’t you guys just maybe think that Nature does all the collapsing and you just get to observe it?
That’s certainly a possibility; indeed it’s the one that GRW and Roger Penrose advocate. But then the burden falls on the proponent to say: how does Nature decide when to trigger a “collapse” and when not to? And how is it that we haven’t yet noticed the effects of such “objective collapses” in experiments—even with superconducting qubits involving billions of electrons, or with molecules of hundreds of atoms traveling through a superposition of slits? What sort of experiment do you predict will reveal these collapses?
141. Utter Hypocrite Says:
Mitchell Porter,
Quickly scanning sources closely at hand, I’d say that loosely speaking a “world” is a complex, causally connected, partially or completely closed set of interacting sub-systems which don’t significantly interfere with other, more remote, elements in the superposition. Any complex system and its coupled environment, with a large number of internal degrees of freedom, qualifies as a world. An observer, with internal irreversible processes, counts as a complex system. In terms of the wavefunction, a world is a decohered branch of the universal wavefunction, which represents a single macrostate. The worlds all exist simultaneously in a non- interacting linear superposition. Worlds “split” upon measurement-like interactions associated with thermodynamically irreversible processes. How many “worlds” are there? The thermodynamic Planck-Boltzmann relationship, S = k*log(W), counts the branches of the wavefunction at each splitting, at the lowest, maximally refined level of Gell-Mann’s many-histories tree.
This approach accepts the reality of the wave function and the QM formalism without bolting on a collapse postulate. This may not be “coherent” enough for you, and I don’t have the knowledge or background to argue the technical points, but a fair-mined person should, I think, acknowledge that this type of analysis is a reasonable, good faith effort to answer these difficult questions, and that the label “utter hypocrites” is a bit strained.
Now it’s your turn. What about this ‘collapse’ law? Do you have to be conscious to collapse stuff? Can a frog or a robot collapse wavefunctions? At what point does the collapse happen: the optic nerve? the visual cortex? the soul? Or does it just happen whenever you, like, entangle more than some special number of atoms? What is the magic number, then?
142. itai Says:
Hi Scott,
I thought about some anomaly stuff that exists in the basics of probability theory , that could have some implication in QM: Max Born probabilistic interpretation and Uncertainty principle, and maybe in TCS.
And it will insert some set theory based math to physics( measure theory which is basis of modern probability is based on set theory) .
QM physics and any statistical theory presume strong law of large number holds all the time ( when n->inf average=mean )
But The strong law of large number holds only when the expected value of probability density function converges surely ( by the mean of Lebesgue integration),
there are many probability density function that either the expected value or second moment does not hold this condition( they can converge by other types if integral such as improper reiman or gauge integral
( see here the status on integration definition in math http://www.math.vanderbilt.edu/~schectex/ccc/gauge/
gauge integral also has some connection with QM path integration)
so if some wave function has no first or second moment according to Lebesgue integration then what is the SD and expected value of position for example?
And if there is no such wave functions ( I don’t think it’s true because Cauchy/Lorentzian distribution is in use now) , then such limiting conditions should be taken into account .
( adding to the demand that integral |Psy|^2 dx =1,
integral |x|*|Psy|^2 dx < inf
and
integral x^2*|Psy|^2 dx < inf
)
143. wolfgang Says:
@Utter Hypocrite #141
Your questions are somewhat misguided to a Copenhagener, who is not talking about an “objective collapse’.
*I* decide to reduce the wavefunction after a measurement, because it is not longer the most economic description of reality; This is a matter of convenience and therefore your questions cannot be answered as such.
144. Jerry Says:
Re Scott #88 (anti-anti Platonist)
Like the Grandfather Paradox, not-not-Platonist could mean Scott has a 50% chance of being a Platonist and 50% of being an anti-Platonist. See:
http://www.math.harvard.edu/~mazur/papers/plato4.pdf
145. James Gallagher Says:
Scott #141
Sorry I opened my big mouth again, especially after saying I would retire from commenting lol 🙂
It’s Easter, traditionally a time of peace, so I will tread carefully, I will just respond by saying that there is NO current experiment which indicates that collapse is not occurring – even the observations made in quantum zeno experiments are entirely consistent with a single path evolution in Hilbert Space – AS LONG AS that path is probabilistically generated! (ie every single collapse is probabilistic)
However, as you know, I believe that we will start to observe performance issues which large scale QC which will not be explainable by decoherence issues. The “scale” at which this will happen is of course the thing I should be able to predict, before opening my big mouth again.
Happy Easter!
146. Utter Hypocrite Says:
“”*I* decide to reduce the wavefunction after a measurement, because it is not longer the most economic description of reality; This is a matter of convenience and therefore your questions cannot be answered as such . . .”
Look, I’m not saying that you shouldn’t adjust your thinking because you happen to come into possession of more information. But don’t tell me you are, as you seem to hint, a hardcore solipsist; if you think that not only the limited world we can observe, and the “universe” we can surmise, but everything there is or could ever be, depends on what you may happen to come up with.
And this is your reason for not being able to at least try and answer my questions? Seriously, give it a try.
147. wolfgang Says:
>> Seriously, give it a try.
OK, one more time (I promise it is the last time).
We follow the advice of the famous philosopher Rumsfeld and divide the world into those three parts:
1) the known unknown: the qubits which we can describe with a wavefunction.
2) the unknown unkown: the internal state of the environment, which includes large parts of the observer.
3) the known: my mental state (it is all I really know)
Where one draws the line between 1) and 2) and 3) is up to the particular experimental situation. Perhaps you can arrange it so that nerve cell 563,783,123 in your right eye is part of 1) but in most cases it will be part of 2)
I can ensure you that 1) will always be smaller than 2) and therefore talk about a universal wavefunction is not economic.
I can also tell you that it would not be very economic to describe 3) with a wavefunction, because I know what I know.
So when the wavefunction from 1) entangles with 2) during the experiment, decoherence sets in and when it finally reaches 3) it is reduced.
But again, trying to describe this with one wavefunction would not make much sense … therefore your questions are misguided.
148. itai Says:
wolfgang,
will you consider wave function without surly converges ( lebesgue converges ) of first/second moment ( no SD ) to be the unknown unknowns ?
or will you consider them physically impossible ?
149. wolfgang Says:
@itai #148
in many cases the lazy physicists imagine the experiment to happen in some sort of box (e.g. the laboratory), using appropriate boundary conditions to make sure the integral(s) over the wavefunction(s) converge.
If one talks about the ‘wavefunction of the universe’ etc. your problem could become a real issue (how do yo normalize the universal wavefunction?)
Btw one needs to keep in mind that in real experiments we often do not know the correct physics yet – this is why we do the experiment in the first place. So we do not know the wavefunction before the experiment.
How does a mwi proponent a la Tegmark describe this situation? Did the multiverse split into different branches, with e.g. different masses for the Higgs?
150. itai Says:
@wolfgang #149
I know in physics we normalize wave function, otherwise it was not legal distribution function.
strong law of large numbers ( what assure us average as n->inf equals expectation) does not hold for all distributions (when first moment does not converges surely ), also some distribution have first moment but infinite variance ( second moment not converges surely ) .
my question is whether wave function can act like this ?
if it is physically possible what does it mean for Uncertainty principle .
if it’s not physically possible wave function , does someone take this into account, so we can add some more constraints for legal wave function?
( i know Cauchy and Levy distribution are is in use in physics world i have no idea if it has any connection to wave function , i have numerous other distribution examples )
151. fred Says:
itai #150
But in QM the probability distribution is from the square of the modulus of the amplitude. So the distribution is always positive, no? I don’t think it’s possible to get the moments you suggest with strictly positive values, no? (I could be wrong, I’m no expert)
152. itai Says:
fred #151
The distribution of wave function in QM as far as i know are from -inf to inf , only the probability is always positive or zero
( absolute value of wave function squared ).
So i don’t see any theoretical reason for wave function first moment is always integrable by absolute value nor second moment.
Anyway, it is possible for positive values only distribution to have no second moment and do have first moment
( meaning variance is infinite ).
for example, for X=1/sqrt(U) where U is uniform distribution.
It has density function of f(x)=2*x^(-3) ,X>=1.
Var(X) = infinity, but E(X) =2 .
153. Douglas Knight Says:
Scott: As a general rule, it’s about a trillion times easier to write a correct program…when the program’s only purpose is to solve some fixed, well-defined math problem, rather than interfacing with a wide array of human users in a way that’s secure against any of those users who might be malicious and exploit vulnerabilities in the code!
That’s true, but presents a false dichotomy. One strategy for writing secure code is to formalize the requirements. Ideally in a DSL that generates the actual code. That doesn’t address most side channel attacks (timing, compression,…) but it does address many other attacks, such as Heartbleed and the recent validation problems. cf langsec. (All of which is completely orthogonal to your point.)
154. srp Says:
I don’t know if I buy the simple reversibility argument. Suppose we were to fracture a piece of glass into two pieces by applying a specific force vector to it. I don’t really believe that it would reform into a single piece if the force vector were exactly reversed. And I don’t think the problem is one of not being able to get exact enough coordinates to get the vector reversed. There’s something going on with the way molecular bonds work so that the newly created surface is not “open” to re-bonding with the other piece in the way it was configured before. (It might be instructive to compare putty-like to rigid materials in this regard.)
Obviously, there must be some threshold size of object where this phenomenon would first set in, because single-particle processes are observed to be reversible. I don’t know if it’s the atomic, the molecular, the ten-molecule, etc. level where this happens. But it might be more instructive to focus on this sort of specific material system rather than generalized abstract systems to get some intuition about the mechanisms involved in irreversibility.
155. Scott Says:
srp #154: Yes, the glass would coalesce back together, and it’s not a matter of debate or opinion. It’s 18th-century physics, emphatically upheld by everything that’s come since.
Keep in mind, however, that you would need to perfectly reverse not merely the motions of the glass molecules, but also the motions of all the photons that escaped, all the motions that those photons caused after getting absorbed by electrons somewhere else, etc. If you time-reverse everything (well, and also reverse left and right in weak decays, and reverse matter and antimatter, in the unlikely event that either of those is relevant 🙂 ), then you’ll certainly obtain another valid solution of the equations of physics. It will just be one with an extremely bizarre initial condition, one that has the bizarre property of causing a pristine glass to form out of fragments.
156. srp Says:
I don’t see in this case how to reverse a photon’s motion exactly since it doesn’t have a classical trajectory and seems like it might come up with a different “collapse” in terms of polarization, etc. when it gets “measured” by the fracture surface (compared to its “measured” state when it flew away from the fracture surface). I thought these kinds of measurements have stochastic outcomes, but likely there is some aspect of the theory I’ve overlooked.
In any case, assuming I am wrong, perhaps there is room for some careful measurement of this phenomenon with very small matter clusters, gradually increasing their size (and maybe varying their rigidity) to see where the finickiness of the initial conditions sets in. It’s relatively easy (there’s a wide range of initial conditions) to get two fundamental particles to reverse a decay process or a collision that led to fragmentation. It’s almost impossible to do it with a storm window. Somewhere in between is the knee of the finickiness curve.
157. Serge Says:
Scott #102:
“In comparing Heartbleed to hypothetical bugs in a quantum computer, I feel like you’re conflating two extremely different issues. As a general rule, it’s about a trillion times easier to write a correct program—whether classical or quantum!—when the program’s only purpose is to solve some fixed, well-defined math problem, rather than interfacing with a wide array of human users in a way that’s secure against any of those users who might be malicious and exploit vulnerabilities in the code!”
Actually, this conflation was made on purpose. As Poincaré used to say, mathematics is the art of giving different things the same name. It seemed indeed interesting to me to compare an attempt to solve a fixed, well-defined math problem by quantum means, with an attempt to solve some real-world security issue by classical means. In both cases, elements of uncertainty are at work so that a plethora of malicious users could play the role of the fundamental indeterminacy of quantum mechanics. In such a view, the difficulties encountered in building a quantum computer appear as a consequence of some general principal one might call “the uncertainty of the fight against uncertainty”. It bears some ressemblance with the (possible) unprovability of the unprovability of P≠NP.
158. Itai Says:
Scott,
The answer to your quest for a physical law that will explain those observation about computational models is the law of least action.
where action = physics computational complexity.
It is clear why is should be mathematical time complexity as it counts “actions” of computation machine and not actual time !
Action is not always minimal can exlpain the problem in solving NPC problems !
http://www.eftaylor.com/pub/Gray&TaylorAJP.pdf
159. T Says:
What about a warp bubble computer? Let me be the first to say that I don’t really know what I’m asking.
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2016-09-26 00:12:43
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https://socratic.org/questions/what-is-7pi-6-radians-in-degrees
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# What is (7pi)/6 radians in degrees?
In degrees, $\frac{7 \pi}{6}$ is 210°.
pi = 180°, so, we will use some logic here.
pi/6 = 180/6 = 30°
7 * pi/6 = 7 * 30 = 210°
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2021-06-20 08:55:32
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https://www.yccbio.net/2018/07/14/seeking-signal-in-the-midst-of-noise-with-r/
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# Seeking signal in the midst of noise with R
Photo by Anton Scherbakov on Unsplash
Oftentimes, the sample I deal with is full of noise or confounding factors that I am not interested in. For example, human specimen is doomed noisy because the race, age, sex, occupation, or the life story of the subject would have influenced the results. Careful matching those statistics and increasing sample number would help a lot minimize known confounding factors and have a better chance to cancel other unknown factors, but sometimes sample number is just beyond our control.
I become curious about *how well differential expression analysis works
• on this kind of dataset and whether other techniques could help us fish signal from noise.
Thus, I decided to make a dataset, in which 10 out of 100 “genes” are informative. In this dataset, there are 8 samples, with their disease state being either 0 (healthy) or 1 (diseased); sex being either 0 or 1; age being a number between 0–1, which represents age/100; and other factors is represented by a random number between 0–1.
library(ggplot2)
library(cowplot)
##
## ********************************************************
## Note: As of version 1.0.0, cowplot does not change the
## default ggplot2 theme anymore. To recover the previous
## behavior, execute:
## theme_set(theme_cowplot())
## ********************************************************
# Generating subject characteristics
# Disease state
disease <- c(0,0,0,0,1,1,1,1)
# Sex
set.seed(1629)
sex <- as.numeric(runif(n = 8, min = 0, max = 1) > 0.5)
# Hidden confounding factor for each N
hcf <- runif(n = 8, min = 0, max = 1)
# Age
age <- round(runif(n = 8, min = 0, max = 1), digits = 2)
# Meta data table
meta_df <- data.frame(disease, sex, "hidden factor" = hcf, age,
row.names = paste("object", seq(8)))
print(meta_df)
## disease sex hidden.factor age
## object 1 0 0 0.1429998 0.64
## object 2 0 1 0.3183128 0.98
## object 3 0 1 0.1686106 0.57
## object 4 0 0 0.1923663 0.21
## object 5 1 0 0.1288493 0.53
## object 6 1 1 0.5198558 0.64
## object 7 1 1 0.9773168 0.09
## object 8 1 0 0.4264767 0.07
Basic assumption of the simulated subjects is described as:
$$[gene;expression] = [disease] × A + [sex] × B + [age] × C + [other;factors] × D + [noise]$$
Then, the expression of “genes” are calculated considering the age, sex, other confounding factors combined, and technical variation represented by a noise term that varies between 0–0.5.
In the equation above, A is 0.1 for gene #1, 0.2 for gene #2, and 1 for gene #10. A is 0 for the rest of the 90 genes. B, C, and D are randomly generated with the sum of A, B, C, and D restricted to <
1. So, only the first 10 genes are relevant to disease state, and gene #10 is the most representative one.
With these meta data, we can generate a dummy expression matrix:
# Generate dummy data set
## Saving the genes and the random generated coefficients in two lists
feature <- list()
coef <- list()
## Generating 100 genes
for (i in seq(100)) {
# Generate 10 genes that is related to disease
if (i <= 10) {
coef_sex <- runif(n = 1, min = 0, max = (1 - i/10))
coef_hcf <- runif(n = 1, min = 0, max = (1 - i/10 - coef_sex))
coef_age <- 1 - (i/10 + coef_sex + coef_hcf)
noise <- runif(1, min = 0, max = 0.5)
ident <- runif(1, min = 0, max = 2)
basal <- rnorm(n = 8, sd = ident * 0.1, mean = ident)
feature[[i]] <- disease * (i / 10) + sex * coef_sex + age * coef_age + hcf * coef_hcf + noise + basal
coef[[i]] <- c(i/10, coef_sex, coef_age, coef_hcf, noise)
next
}
# The rest 90 genes are not related to disease state
coef_sex <- runif(n = 1, min = 0, max = 1)
coef_hcf <- runif(n = 1, min = 0, max = (1 - coef_sex))
coef_age <- 1 - (coef_sex + coef_hcf)
noise <- runif(1, min = 0, max = 0.5)
ident <- runif(1, min = 0, max = 2)
basal <- rnorm(n = 8, sd = ident * 0.1, mean = ident)
feature[[i]] <- sex * coef_sex + age * coef_age + hcf * coef_hcf + noise + basal
coef[[i]] <- c(0, coef_sex, coef_age, coef_hcf, noise)
}
# Formatting the expression matrix
expression <- do.call("rbind", feature)
coefficient <- do.call("rbind", coef)
colnames(expression) <- c("wt1", "wt2", "wt3", "wt4", "pt1", "pt2", "pt3", "pt4")
colnames(coefficient) <- c("Disease", "Sex", "Age", "HCF", "Noise")
expression <- data.frame(expression)
expression$gene <- c( sapply(seq(10), function(x) paste("real", x, sep = "_")), sapply(seq(90), function(x) paste("noise", x, sep = "_"))) The script above generated something like this: # Transform the expression matrix for plotting expression_l <- tidyr::gather(expression, key = "Subject", value = "Expression", -gene ) # Order the genes by hierarchical clustering row.names(expression) <- expression$gene
gene_dist <- dist(expression[ , names(expression) != "gene"])
gene_hc <- hclust(gene_dist)
expression_l$gene <- factor(expression_l$gene,
levels = rev(gene_hc$labels[gene_hc$order]))
ggplot(expression_l, aes(x = Subject, y = gene, fill = Expression)) +
geom_tile() +
scale_fill_gradientn(colours = c("green", "black", "magenta")) +
labs(x = "", y = "")
From the heatmap, it seems that the other factors is contributing a lot to the difference between samples. Is differential expression analysis capable of finding the genes that are really related to diseases?
library(limma)
log_exp <- log2(expression[, -9])
log_exp$gene <- expression$gene
design <- model.matrix(~ 0+factor(c(0,0,0,0,1,1,1,1)))
colnames(design) <- c("Ctrl","Patient")
fit <- lmFit(log_exp[, -9], design)
fit$genes$ID <- log_exp$gene cont.matrix <- makeContrasts(PatientvsCtrl = Patient-Ctrl, levels=design) fit2 <- contrasts.fit(fit, cont.matrix) fit2 <- eBayes(fit2) volcanoplot(fit2, highlight = 5) tt <- topTable(fit2, number = 20, adjust = "BH") print(head(tt)) ## ID logFC AveExpr t P.Value adj.P.Val ## real_9 real_9 0.9692060 0.2966555 7.263496 5.343801e-05 0.005343801 ## real_5 real_5 1.1761718 -0.7116106 4.611329 1.348025e-03 0.061848855 ## real_8 real_8 0.6875499 0.7299697 4.385535 1.855466e-03 0.061848855 ## real_10 real_10 0.5617334 1.4676770 4.130614 2.685130e-03 0.067128249 ## real_7 real_7 0.5213747 1.1164215 3.843007 4.119657e-03 0.082393143 ## real_6 real_6 0.4883247 0.8115677 3.471073 7.284143e-03 0.121402376 ## B ## real_9 2.338578 ## real_5 -1.010201 ## real_8 -1.342311 ## real_10 -1.725818 ## real_7 -2.168663 ## real_6 -2.755183 It turned out limma did a great job. It hit 3 significantly up-regulated genes (real_10, real_9, and real_8), and from the volcano plot, we could see the disease correlated genes (annotated as “real_x”) are quite visible even if they were not significant. Does fancier tools do a better job in finding real differentially expressed genes in a noisy dataset? I tried caret and Boruta to give machine learning a try. # Reverse feature selection with caret library(caret) exp_rfe <- t(expression[, -9]) colnames(exp_rfe) <- expression$gene
ctrl <- rfeControl(functions = rfFuncs,
method = "repeatedCV",
repeats = 10, verbose = FALSE)
type_exp <- factor(c(0,0,0,0,1,1,1,1), labels = c("0", "1"))
lmProfile_exp <- rfe(x=exp_rfe, y=type_exp,
sizes = c(1:30),
rfeControl = ctrl)
plot(lmProfile_exp, type = c("g", "o"))
predictors(lmProfile_exp)
## [1] "real_9" "real_6" "real_7" "real_10" "real_5"
Reverse feature selection with caret gave me 4 genes (real_7–10), while Boruta rejected every single gene. It seemed that at least for this dataset, traditional differential expression performed at least as well as machine learning approaches.
## Increase the noise term
Interestingly, when I gave noise term a coefficient of 10 instead of 1. limma identified more up-regulated genes (real_6–10), while the results from caret and Boruta remained the same. It was against my anticipation that the real difference would be buried in the noise, so I tried to use a coefficient of 10000. This time limma found even more up-regulated genes (real_4–10)…
## Lower the effect size of disease state
On the other hand, When I made disease term 10 times smaller, limma could not find any significantly up-regulated gene, while caret managed to find one (real_9).
## Increase sample number
Finally, to see whether sample number could improve sensitivity when disease term is small, I tried to do the same analysis on 80 subjects (40 control and 40 diseased). I was expecting both differential expression analysis and machine learning would benefit from a larger sample number.
With 80 samples, limma still could not find any significantly changed genes, caret found 5 (real_4, 6, 7, 8, 9) along with 5 false positive, and there was still no luck for Boruta.
In this short experiment, my impression is that:
1. Effect size and consistency play the most important role in differential expression analysis. A small effect size gets overwhelmed by confounding factors and noise, while larger ones could be detected even with a large noise term.
2. With a small sample size, result of reverse feature selection with caret and limma are not much different than each other.
3. When effect size is small, increasing sample number helps a bit in limma (adjusted p value goes down with increased sample number). caret seems to benefit more from larger sample number (because it’s machine learning?), but even with more samples, false positive is quite concerning.
I guess the difficult choice between sensitivity and specificity would still be an issue here. Though I hoped machine learning could work like magical black box, it performed similar to traditional approaches. I would need to learn more about the basics of machine learning before I could tell if there is some better way doing this.
###### PhD Student
A graduate student interested in developmental biology, neurobiology and bioinformatics.
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2021-04-10 11:05:09
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https://sikademy.com/answer/computer-science/discrete-mathematics/write-the-following-logical-arguments-as-predicate-expre-pnol/
|
is below this banner.
Can't find a solution anywhere?
NEED A FAST ANSWER TO ANY QUESTION OR ASSIGNMENT?
You will get a detailed answer to your question or assignment in the shortest time possible.
## Here's the Solution to this Question
a)
U- set of allpeople
C- students of this class
P:U->{0,1}- predicat,P(X)=1~man X$\in$ U has Honda bike.
Q:U->{0,1}-predicat,Q(X)=1~ man X has gotten at least one traffic violation challen.
Given that $P(Asim),\forall(X\in U)(P(X)->Q(X))$
From specialization rule we have $P(Asim),P(Asim)->Q(Asim)$
Therefore by modus ponens rule Q(Asim), but $Asim\in C$
By definition $\exist$ we have $\exist (X\in C) Q(X).$
b)
U- set of all students.
P:U->{0,1}-predicat, P(X)~X has taken discret structure course
Q:U->{0,1}-predicat ,Q(X)~ X can take algorithm course.
C- set of five roommates, |C|=5,
Statement is
$P(Azhar),P(Haris),P(Nouman), \forall(X\in U)(P(X)->Q(X))->\forall(Y\in C)Q(Y)$
is not true because there is such interpretation that left part true but right part is false. Evidently C\{Azhar,Haris,Nouman}$\ne\empty$ .
Let $a\in C$ \{Azhar,Haris,Nouman},in interpretation we assume P(a)=Q(a)=0,
P(Azhar)=P(Haris)=P(Nouman)=Q(Azhar)Q=(Haris)=Q(Nouman)=1
Then $\forall(Y\in C)Q(Y)=0$ and $P(a)->Q(a)=\overline{P(a)}\lor Q(a)=\overline 0 \lor 1=1$ , therefore
$P(Azhar),P(Haris),P(Nouman), \forall(X\in U)(P(X)->Q(X))->\forall(Y\in C)Q(Y)=1$
Thus statement is not true.
c)
P(X)- movie X is wonderful.
Q(X) movie X produced by John Sayles.
R(X) movie X is about coal miners.
U-set of all movies.
Statement is:
$\forall(X\in U)(Q(X)\rarr P(X)),\space \exist(X\in U)(Q(X)\land R(X))\rarr \\ \exist(X\in U)(R(X)\land P(X))$
Proof:
$\exist(X\in U)(Q(X)\land R(X))\implies Q(a)\land R(a)$
concretization;
$\forall(X\in U)(Q(X)\rarr P(X))\implies Q(a)\rarr P(a)$
spesialization
$Q(a)\land R(a)\implies Q(a)$
conjuction rule
$Q(a),Q(a)\rarr P(a)\implies P(a)$
modus ponens
$Q(a)\land R(a)\implies R(a)$
conjuction rule
$P(a),R(a)\implies P(a)\land R(a)$
build conjuction rule
$P(a)\land R(a)\implies \exist(X\in U)(R(X)\land P(X))$
build existence rule
d)
P(X)~ X has been to Saudi Arabia
Q(X)~X performs Umrah
U- set of all people
C- this class
Statement:
$\exist (X\in C)P(X),\space \forall(X\in U)(P(X)\rarr Q(X))\implies \exist(X\in C)Q(X)$
Proof:
a$\in$ C, P(a)- conctetization'
P(a)->Q(a)- specialization;
$P(a),P(a)\rarr Q(a)\implies Q(a)$
modus ponens
$Q(a)\implies \exist(X\in C)Q(X)$
definition of $\exist$
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2022-07-06 10:39:45
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https://zbmath.org/?q=an%3A1301.05382
|
# zbMATH — the first resource for mathematics
The $$f$$-vector of a representable-matroid complex is log-concave. (English) Zbl 1301.05382
Summary: We show that the $$f$$-vector of the matroid complex of a representable matroid is log-concave. This proves the representable case of a conjecture made by J. H. Mason [“Matroids: unimodal conjectures and Motzkin’s theorem”, in: D. J. A. Welsh (ed.) et al., Combinatorics. Proceedings of the conference on combinatorial mathematics held at the Mathematical Institute, Oxford, 1972. Southend-on-Sea: The Institute of Mathematics and its Applications. 207–220 (1972; Zbl 0469.05001)].
##### MSC:
05E45 Combinatorial aspects of simplicial complexes 05C31 Graph polynomials 05B35 Combinatorial aspects of matroids and geometric lattices
Full Text:
##### References:
[1] Brylawski, Thomas, The Tutte polynomial. I. general theory, (Matroid Theory and Its Applications, (1982), Liguori Naples), 125-275 · Zbl 1302.05023 [2] Brylawski, Thomas; Oxley, James, The Tutte polynomial and its applications, (Matroid Applications, Encyclopedia Math. Appl., vol. 40, (1992), Cambridge Univ. Press Cambridge), 123-225 · Zbl 0769.05026 [3] Brylawski, Tom, The broken-circuit complex, Trans. Amer. Math. Soc., 234, 417-433, (1977) · Zbl 0368.05022 [4] Huh, June, Milnor numbers of projective hypersurfaces and the chromatic polynomial of graphs, J. Amer. Math. Soc., 25, 907-927, (2012) · Zbl 1243.14005 [5] Huh, June; Katz, Eric, Log-concavity of characteristic polynomials and the Bergman Fan of matroids, Math. Ann., 354, 1103-1116, (2012) · Zbl 1258.05021 [6] Lenz, Matthias, Matroids and log-concavity, (2013) · Zbl 1301.05382 [7] Mason, John H., Matroids: unimodal conjectures and motzkinʼs theorem, (Proc. Conf. Combinatorial Math., Math. Inst., Oxford, 1972 (Southend-on-Sea), (1972)), 207-220 [8] Oxley, James G., Matroid theory, Oxford Sci. Publ., (1992), Clarendon Press, Oxford University Press New York · Zbl 0784.05002
This reference list is based on information provided by the publisher or from digital mathematics libraries. Its items are heuristically matched to zbMATH identifiers and may contain data conversion errors. It attempts to reflect the references listed in the original paper as accurately as possible without claiming the completeness or perfect precision of the matching.
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2021-03-08 21:47:40
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http://math.stackexchange.com/questions/173137/ratio-and-divisibility
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# Ratio and divisibility
Given that $5x=3y=z$ where $x, y, z$ are integers, each choice given below must be integer except?
A) $z/15 \quad\quad$ B) $z/5 \quad\quad$ C) $z/3 \quad\quad\\$ D) $z/xy \quad\quad\\$ E) $x/3$
(Ans=D)
How would I solve this problem any suggestions ?
-
The best way to solve this type of problem is to plug some numbers in, and try to get a feel for WHY the various expressions either have to be integers, or don't have to be. It shouldn't take very long to discover that $x$ must be a multiple of 3, $y$ must be a multiple of 5, and that we can write $x=3w$, $y=5w$ and $z=15w$ for some integer $w$.
Since this is clearly a question in a quick-fire multiple choice test, a rigorous proof is unlikely to be needed. In fact, we've already done enough to show that A, B, C and E are not the correct answers. So circle D and move on to the next question. If "none of the above" had been one of the options, then keep going - eventually you'll try $w=2$, and discover that D is indeed correct.
-
Why $15$ divides $z$ (meaning that $z/15$ is an integer): If a prime, in this case $3$, divides a product, in this case $5x$, then the prime must divide one (or both) of the terms. Since $3$ does not divide $5$, we conclude that $3$ must divide $x$.
So $x=3t$ for some $t$, and therefore $x=15t$. We conclude that $15$ divides $z$.
The same kind of reasoning (but easier) shows that $z/5$, $z/3$, and $x/3$ are integers. In fact, we have already shown all these things in the process of showing that $15$ divides $z$. So by a process of elimination, the right answer must be D).
But we can see separately that $z/(xy)$ is not necessarily an integer. For example, let $x=6$, $y=10$, and $z=30$. Then your conditions are met, but $xy$, which is $60$, does not divide $z$.
Note that $z/(xy)$ can be an integer, if $x=3$ and $y=5$. These are in fact the only positive cases when under our conditions, $z/(xy)$ is an integer.
-
I can see z is divisible by all other options however for $\frac{z}{xy}$ I am assuming $x = 3 \times 5$ and $y=5 \times 3$ it is also divisible . Am I wrong ? – MistyD Jul 20 '12 at 6:39
If $x=3\times 5$ and $y=5\times 3$, then it is not true that $5x=3y$. I think you meant $x=3$, $y=5$. That certainly is a possibility, and then $z/xy$ is an integer. But there are other possibilities for $x$ and $y$, like the $6$ and $10$ I mentioned. With those, and $z=30$, it will be true that $5x=3y=z$. But for that choice of $x$ and $y$, the number $z/(xy)$ is $30/60$, which is not an integer. So it is not true that $z/(xy)$ must be an integer. (But it can be.) – André Nicolas Jul 20 '12 at 6:50
Thanks that helps – MistyD Jul 20 '12 at 6:57
We have $5x=3y$, or $x \div y = 3\div 5$
Let their greatest common divisor be $k$, where $k$ is constant ;
So $x=3k$, $y=5k$, we have $z=5x=5*3k=15k$; so $z/xy =15k/(3k*5k)=1/k$; and $1/k < 1$, as $k$ is constant $1/k$ is not an integer
follow the same style for other options and you will found the answers are integer,
Thus and (d) $z/xy$ is correct;
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2014-10-30 13:54:01
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https://ci2ma.udec.cl/publicaciones/prepublicaciones/prepublicacion.php?id=465
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CI²MA - Publicaciones | Prepublicaciones
## Tomás Barrios, Edwin Behrens, Rommel Bustinza:
### Abstract:
We analyze a new stabilized dual-mixed method applied to incompressible linear elasticity problems, considering two kind of data on the boundary of the domain: nonhomogeneous Dirichlet and mixed boundary conditions. In this approach, we circumvent the standard use of the rotation to impose weakly the symmetry of stress tensor. We prove that the new variational formulation and the corresponding Galerkin scheme are well-posed. We also provide the rate of convergence when each row of the stress is approximated by Raviart-Thomas elements and the displacement is approximated by continuous piecewise polynomials. Moreover, we derive a residual a posteriori error estimator for each situation. The corresponding analysis is quite different, depending on the type of boundary conditions. For known displacement on the whole boundary, we based our analysis on Ritz projection of the error, and requires a suitable quasi-Helmholtz decomposition of functions living in $H(\mathbf{div};\Omega)$. As a result, we obtain a simple a posteriori error estimator, that consists of five residual terms, and results to be reliable and locally efficient. On the other hand, when we consider mixed boundary conditions, these tools are not necessary. Then, we are able to develop an a posteriori error analysis, which provide us of an estimator consisting of three residual terms. In addition, we prove that in general this estimator is reliable, and when the traction datum is piecewise polynomial, locally efficient. In the second situation, we propose a numerical procedure to compute the numerical approximation, at a reasonable cost. Finally, we include several numerical experiments that illustrate the performance of the corresponding adaptive algorithm for each problem, and support its use in practice.
Descargar en formato PDF
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2022-07-01 05:44:23
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https://mattermodeling.meta.stackexchange.com/questions?tab=newest&pagesize=30
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# All Questions
116 questions
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39 views
### 0 downvotes in 2 weeks, across ~3500 users!
When examining the stats from 13 October to 3 November, we find that our ~3500 users have in total only downvoted once (on 15 October) and we went more than 2 weeks without ever downvoting. Thanks for ...
159 views
I have some very exciting news to share: On December 16th, our site is officially moving out of Beta! This is a great sign that the SE network has faith in our site and thinks we are a valuable ...
74 views
### How would we like to describe ourselves?
Currently our site is described as: "Q&A for materials modelers and data scientists" This was chosen by Robert Cartaino during Area51, with no input from our community. I think it's ...
72 views
### Do we want to change the way we pin "accepted" answers to the top?
SE is making the way accepted answers behave configurable per-site and is looking for input from our side as to what our preference is. Currently, accepted answers - answers that the asker of the ...
99 views
### Are questions about topics proximate to, but not exclusive to, matter modeling on-topic for the site?
I'm asking this because of a recent string of questions*: Which image format is best to use in a scientific paper? How can I learn LaTeX? How to determine the right size of Gnuplot terminal output? ...
62 views
### We hit rock bottom last week, in voting. What can we do now to encourage people to vote more?
I was very disappointed to see that we hit a record low in number of votes cast on our site this past week, despite us having a record high in number of total users and number of total questions on ...
76 views
### Why do we have so few active users from the UK or Germany?
The research output from UK and Germany are disproportionately large compared to other European countries (which you can see based on the number of Marie Curie or ERC grants awarded/capita to people ...
13 views
### MMSE Virtual Poster Session
I mentioned as a comment to the Town Hall Meta Post the possibility of organizing a virtual poster session on the Gather Town platform for the MMSE community. I've found the gather town platform to be ...
29 views
### Does bumping 16 questions from the unanswered queue, enter the stage where it becomes a little counterproductive?
I've many times bumped up unanswered questions by improving them with edits, and found that they got answered shortly after, so this was indeed helpful. However this time I did 16 questions at once: ...
24 views
### Where would hierarchical tagging help us?
In light of this answer, I thought I might put together a list of where hierarchical tagging would help us, for example: software can including things like software-recommendations python can ...
81 views
### Is there anything the Matter Modeling community needs from the SE company?
In light of this question that was asked yesterday on the Mother Meta: Magic wand time - what does your community need? (More questions from the Community VP), is there anything we need?
92 views
### An unusual pattern of unregistered users?
There's probably far more, but these are the ones that I had in my notes, which I noticed mainly based on Q/A they posted: Link User ID User IDs between 0-999: https://mattermodeling.stackexchange....
30 views
### Preserving Comments and Chat Integration
I thought it might be worth making a brief explainer on one of the slight differences in protocol we have developed compared to other sites in the network: comment preservation. On a lot of sites in ...
37 views
### Pending edits on posts, to be made when the site is lower in traffic
We are burninating the hessian tag, and I finished half of this job by removing the tag from all of the unanswered questions. I'm hesitant to remove the tag from the other two which already have ...
11 views
### More opportunities to help MMSE with your artistic skills!
First, I'd really like to thank Anoop Nair and Pranoy Ray for their help with: Logo needed for community ads! and Let's work on our logo! (Improving on Anoop Nair's design). Everyone is ...
14 views
### An excellent 2.5 months for the review queues, let's continue alternatives to close voting!
In February we had 6 questions in the close vote queue that we ultimately decided to keep open. In March we had 4. In April we had 1. In May we had 0. Since 26 march we've had only 1. In fact for more ...
68 views
### MMSE Community Promotion Board
Taking the suggestion from Geoff Hutchison in Highlighting Matsci.org forum - community promotions, I decided to put together an MMSE page for community ads. Simply add an answer with a title, a brief ...
155 views
42 views
### Highlighting Matsci.org forum - community promotions
At the moment, I don't think there are community promotion ads for 2021. I came across the https://matsci.org forum, which was started in 2020 and provides discussion for many software packages ...
141 views
### Let's work on our logo! (Improving on Anoop Nair's design)
Out of the logo suggestions so far, I was able to work on the theme proposed by Anoop Nair in his answer, thanks to him making it available for collaboration on GitHub. This is what I have so far, but ...
50 views
### Happy 1 year anniversary!
365 days ago we entered Private Beta and I am almost in tears thinking how far we have come since then! Thank you to all the people who have participated, and congratulations to those that got the ...
88 views
### Annual Town Hall Meeting!
In June 2020 I made the suggestion for us to have weekly town hall meetings, a bit like Quantum Computing SE has "The Quantum Revolution" every Tuesday and Meta.SE has "Happy Hour" ...
103 views
### "8x8x8" or "$8\times 8 \times 8$" or "8 × 8 × 8" or "8×8×8"?
When describing grids, do we want to encourage something like this: or something like this "8 × 8 × 8" or "8×8×8": or something different like Disadvantages of MathJax: it's a ...
46 views
Software recommendation questions are on-topic here, and it's even one of our most popular tags: software-recommendations. However we haven't talked much about how we should approach such questions, ...
103 views
### Why did these questions of mine get a negative score?
I feel like I have good ideas on changes the world could make. I know questions asking people in invest in new research to answer cannot be answered. So I asked questions about existing research. I ...
85 views
### Please make it an aim to vote on questions, even if they aren't your own
In our early days we voted 450 times on 45 posts (10 votes/post), and this shrunk to 337 votes on 55 posts (about 6 votes/post) in July, and seems to have shrunk to nearly 0 votes in the last couple ...
68 views
### New Text Editor issues with Mathjax
Just wanted to bring this to everyone's attention. StackExchange is in the early stages of replacing the current text editor for questions/answers with a new one that supports rich-text. The problem ...
101 views
### How get started "supporting my project on this site"
I posted previously at Chemistry.meta.SE: https://chemistry.meta.stackexchange.com/questions/4889/. Same question, but I'll be a little more brief, because I get the sense that this is, in fact the ...
75 views
### 2020: a year in moderation
As we say goodbye to the old year and welcome the new one, we have a tradition of sharing moderation stats for the past 12 months. As most of you here are aware, sites on the Stack Exchange network ...
229 views
### At what stage would we want to implement a close-vote ban on a user?
First of all thank you to everyone who has been participating in the reviews to help moderate this growing community! On the Stack Exchange network, there is the concept of banning someone from ...
124 views
### Is education advice on-topic for this site?
Disclaimer: I came from hot network posts and I have zero experience here. That said, the post in question is Is it Better For Me to Study Chemistry or Physics? In most other sites I observed, none ...
159 views
### HATS !!!!! GET SPECIAL HATS ON 21 DEC, 25 DEC, AND 1 JAN!
Participation tends to drop badly as we enter the Christmas and New Year period, just as it may have dropped in November due to Diwali. For a small and new site like ours, we might not be able to ...
63 views
### Preparing for a feature request for more flexibility and control over moving comments to chat rooms
"Comments are not for extended discussion", the Stack Exchange system always tells us if it detects two people getting into a 2-way discussion in the comments of a question or answer. ...
164 views
### What can our community do, to get people participating more on our Meta?
Participation in our Meta seems to be somewhat lacking, and I've asked a number of questions lately that have gone unanswered: For the most part I was naming chatrooms myself, and I invited the ...
147 views
### Accepting proposals for chat rooms
I very much would like to avoid this problem: Avoiding making so many new chatrooms called "Discussion between user[A] and user [B]" which later become frozen or not very useful We have a ...
184 views
### If a question already has a good answer, does it need to be closed?
I was the first close voter for this question: Can DFT be considered an ab initio method?. But I have cast a re-open vote now. The question has two good answers (one of them is deleted, because I told ...
117 views
Certainly the list of unanswered questions will get bigger over time, but I was really hoping it would stay under 2 pages long (when listing 50 questions/page) for much longer. The longer the list of ...
53 views
64 views
### How can data be extracted from the Matter Modeling Beta?
As far as I can see, Beta sites are not part of StackExchange data dumps https://archive.org/details/stackexchange . According to https://meta.stackexchange.com/a/216245/884991, sites in public beta ...
102 views
### New Stack Exchange site proposal: Computational Fluid Dynamics!
There's a proposal at the moment for creating an SE site for computational fluid dynamics, and if you would like SE to add a site for this topic, I suggest you follow the proposal, ask some example ...
184 views
### 0 Question Days
In August we had at least 1 question each day In September we had 1 day with 0 questions In October we had 3 days with 0 questions 16 November was already day number 5 with 0 questions in November. ...
77 views
### Advocate this site through PsiK site?
I think to broaden the user base we could make this site publicly known through Psi-K. What do you think? Do you have any sugar text for this, I would be happy to send the mail to Psi-K, or one of you,...
56 views
### Preparing for a feature request for chat rooms to have something like the "@channel" feature in Slack
I'm going through the unanswered questions list to try to get things answered, and I found this: Setting multiple new atype/dtype/itype with LAMMPS fix bond/create, for which I'd like to ping all ...
209 views
### We've recently had questions answered immediately by the same user, shall the answer be made a community wiki as a policy in such cases?
The topic of self-answering questions immediately is a complex one. On one hand we do not want to fill up the site with low-quality material by people hungry for raising their reputation. On the other ...
187 views
### 1 day left to fulfill your commitment!
Users that "committed" to this site before it was launched into Beta, promised to write at least 10 questions or 10 answers within the first 6 months of Beta. Users that fulfill their ...
228 views
### We have let our answer ratio slip, let's do something about it!
Two days ago I asked our community if anyone thinks they know why or how this happened: We've never had such a long string of unanswered questions before, what might be the reason it happened ...
162 views
### We've never had such a long string of unanswered questions before, what might be the reason it happened recently?
This screenshot says it all: All these questions were bumped to the top on September 26th, and none of them have got answers. They are about VASP, LAMMPS, Quantum ESPRESSO, QMC, and TDDFT, all which ...
84 views
### Software recommendations for X or Y
Today we got a software recommendation code which was asking for a code that can do TDDFT or BSE: Is there any DFT code or software that implemented forces of TDDFT or BSE calculations for solids? ...
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2021-11-27 09:04:28
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https://www.physicsforums.com/threads/choosing-unit-vectors-for-harmonic-motion-problems.792447/
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# Choosing unit vectors for harmonic motion problems
1. Jan 15, 2015
### Incand
Consider a vertical pendulum affected by gravity (See the pdf file i included). Now i can choose two different opposite directions for my unit vectors which give me different equations.
$$\downarrow : m\ddot x = mg-kx$$
$$\uparrow : m\ddot x = kx-mg$$
Which of course makes perfect sense, changing direction changes the sign. The problem is now if i want to solve them the second case yields a weird result.
so in the first case the (real) solution would be (if we set $\omega _n^2 = \frac{k}{m}$)
$$x = Acos(\omega _n t )+ Bsin(\omega _n t) + \frac{mg}{k}$$
and for the second case
$$x = Ae^{\omega _n t} + Be^{-\omega _n t} +\frac{mg}{k}$$
So what I'm wondering why i would get a different solution just by changing the direction of the unit vector and how i can reconcile the approaches or know how i should choose the direction of my unit vectors.
#### Attached Files:
• ###### Springh.pdf
File size:
7.1 KB
Views:
75
2. Jan 15, 2015
### PeroK
Whatever your direction for x, the force of the spring is always in the opposite direction to the displacement. So, in the second case, you should have:
$$\uparrow : m\ddot x = -kx-mg$$
3. Jan 15, 2015
### Incand
Thank you, I understand now! You won't believe I've been thinking about this for several hours before i wrote this :)
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2017-08-17 10:55:47
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https://cortexjs.io/mathlive/guides/lifecycle/
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# Web Component Lifecycle
A mathfield web component goes through various stages during its lifecycle.
In most cases, this is something you don’t have to pay much attention to. Just remember these guidelines:
• Once a component is attached to the DOM attributes (key/value pairs attached to the <math-field> tag and properties (key/value pairs attached to a MathfieldElement object) are kept in sync, or reflected. You can also call the methods of MathfieldElement without limitations. You can be notified of this state by listening for a mount event on the element.
• Before the component is attached to the DOM or even before the MathfieldElement class has been registered, you can still interact with the element, but with some limitations. The value, selection, options and disabled properties and related attributes are safe to set, but the values you read back may be different than once the component is mounted.
## Initialization
The element has been created from markup, but the code registering the <math-field> tag with the MathfieldElement class has not been executed yet. This could happen if the scripts are loaded in an unexpected order or if there is a temporary networking issue.
At this stage:
• you can read and change the disabled, value, options, selection and position properties on the element.
document.querySelector('math-field').value = '\\sin x';
However, some of those properties behave in limited way. For example, the options property usually return the default value for the options. However, at this stage, it will only return the values you have set.
• you can change/add/remove attributes on the element. At this stage, the attributes and the properties are independent, so if you set for example the virtual-keyboard-mode attribute, it will not be reflected in options.virtualKeyboardMode.
• the only methods on the element that can be invoked are those of HTMLElement since the element has not been upgraded yet.
To be notified when the registration takes place, use the whenDefined() method.
customElements.whenDefined('math-field').then(() => {
console.log('<math-field> is defined');
});
If all goes well, the element will be constructed next.
## Constructed
This stage occurs either after the previous one (i.e. an element created from markup) or when an element is created programmatically with new MathfieldElement().
The HTMLElement object exist, but it is not yet attached to the DOM. You can interact with the object, but its operations are limited.
At this stage:
• you can read and change the properties as before. However, doing so will be reflected on attributes as well. That is calling mf.setOptions({ virtualKeyboardMode: "manual"}) will result in mf.getAttribute('virtual-keyboard-mode') to return "manual".
• you can read and change the attributes as before, however they will now be reflected on properties as well, that is calling mf.setAttribute('virtual-keyboard-mode', 'manual') will result in mf.getOption('virtualKeyboardMode') to return "manual".
• you can change/add/remove attributes on the element
• you can invoke all methods specific to MathfieldElement, however some may have some limitations. For example setValue() will ignore any options provided including formats other than Latex, executeCommand() will do nothing, etc… These commands required the element to be attached to the DOM to function properly.
## Attached/Mounted
This stage occurs after the previous one. The transition to this stage happens automatically for elements created from markup after the MathfieldElement class has been registered to handle the <math-field> tag. If the element was created programatically, this stage is reached when the element is explicitly attached to the DOM, for example using appendChild().
At this stage:
• you can read and change properties and attributes and they will reflect each other (changing an attribute will update the corresponding property and vice versa).
• you can invoke all properties of MathfieldElement without limitations
To be notified when this stage is reached, listen for the mount event on the element:
console.log('mf is mounted');
// You can now read default options value for example, or
//call setValue()` with format options other than Latex.
console.log(ev.target.getOption('macros'));
});
## Detached/Unmounted
This stage can be reached if the element is explicitly removed from the DOM, for example with ChildNode.remove().
This stage is not reached when the page is closed: in that case the element is immediately disposed of.
Once this stage is reached, the same limitations as in the Constructed stage apply.
Note that the next stage could be either for element to be disposed of or to be re-attached.
To be notified when this stage is reached, listen for the unmount event on the element:
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2020-10-30 22:40:41
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https://www.potfit.net/wiki/doku.php?id=output:tempfile
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# potfit wiki
open source force-matching
### Sidebar
User Guide
Examples
Potential Databases
More
output:tempfile
# Tempfile
The tempfile is written regularly during a simulation, depending on the optimization algorithm. It always contains the potential with the currently lowest sum of squares.
The file can be used to plot the current potential to see if it contains some unwanted features.
### Simulated Annealing
Every time a new minimum in the sum of squares is discovered, the tempfile is written.
### Differential Evolution
Same as Simulated Annealing, tempfile always contains the potential with the lowest sum of squares.
### Powell's Least Squares
Once every time the outer loop has successfully completed. This means after every line that is written to standard output the tempfile is written.
output/tempfile.txt · Last modified: 2018/09/23 11:02 by daniel
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2021-10-20 23:53:02
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{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.4911356270313263, "perplexity": 4254.864455113573}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-43/segments/1634323585353.52/warc/CC-MAIN-20211020214358-20211021004358-00453.warc.gz"}
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https://ask.wireshark.org/question/25144/tls-wireshark-find-failed-tls-handshakes/
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# TLS Wireshark find failed TLS Handshakes
Hello Guys,
I have a Problem with an application "Battle Net" not working in an Deep Packet Inspection enabled environment since 3 days. Before everything was working. Since 3 days the whole internet connection nearly breaks while the Application is running. I waited 5 min for example for google.com to come up while the application was running. When I was looking at task manager I saw that around 100Kbit/s of traffic was flowing not much compared to my 4 Mbit Download Max speed. I looked on the firewalls traffic monitor and there I saw that my whole Bandwidth was used but it was not shown in task manager or resource monitor. The strange thing is that my computer was the only device attached to the firewall at this time and the issues disappeared 10 seconds after I have closed the Application. It was reproduceable. After I disabled Deep Packet Inspection on my Firewall the issue has gone. However I don't want to disable DPI for the whole Internet only for Battle Net. So I wanted to find out which connections failed and started a trace capture.
Then I captured a Trace with Microsoft Network Monitor and saved it as cap file so that wireshark can open it. At first I only exported everything which was in connection with Agent.exe, Battlenet.exe and all the *.exe the battle net launcher used. After I had the data in wireshark I suspected that some TLS handshakes failed and I that I simply need to exempt them from DPI Profil on Firewall. So I set a Display Filter "tls" in Wireshark and there I saw every TLS Packet I guess. Then I thought to get "defective" handshakes I look at the TCP Stream ID and if there is "Application Data" in the Info field. There were many TLS Streams so I exported the data into a mysql database where I did the following statement on all the exported data:
select stream from data where stream not in (SELECT DISTINCT(Stream) FROM data WHERE (Info = "Application Data"))
My Problem was that MySQL didn't returned any data then i checked every tcp stream which was returned in wireshark manually and every stream contained at least a valid Application Data field. So for me this means wireshark is not able to decode the handshake pakets or that there are no invalid tls handshakes right?
Am I right when I'am saying when a tls stream in wireshark does contain at least one application data packet that the tls handshake was successful or am I missing something here?
I have attached 2 trace files one already prefiltered with netmon and the other one the unfiltered one from the same trace.
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I vaguely understand your issue, but all the other detail about your approach to resolving the issue obscures what you're trying to do.
I think you're trying to find TLS connections that don't complete the handshake, is that correct? There are a number of reasons that a handshake may not complete, what do you think the behaviour caused by your DPI is\will be?
Looking at the unfiltered capture there are some TLS conversations which aren't automatically dissected as TLS by Wireshark, e.g. port 8080, 27032 so they may be missing from your analysis. You have to use Decode As ... to set those ports as TLS.
( 2021-11-14 19:55:29 +0000 )edit
Hello grahamb,
yes I'am trying to find TLS Handshakes which wont complete. My Firewall does a Man in the Middle to read what user is doing. So I need to exempt the failed TLS connections from TLS Inspection.
TCP Port 8080 only occurs with one ip 10.0.x.x which is the local ip of my firewall in the other vlan. During the trace i was connected to the webinterface so port 8080 is not important in this case.
I think that "Battle Net" is using some form of certificate pinning or does not use the windows certificate store so some tls connections may fail and i need them to exclude them from dpi.
In my copy of wireshark tcp port 27032 is detected as tls. When I click Analyse -> Decode As -> it shows Field: TLS Port, Value: 27032, Typ: Integer, bas10, Standard: (none), and current ...(more)
( 2021-11-14 21:01:14 +0000 )edit
I used the Analyze->Endpoints dialog, looking at the TCP tab to see what iP\hosts and ports were in the capture. I sorted by port number and discounted all those from the ephemeral port range as likely to be the client side and then filtered by the port tcp.port == xxxx to see what it was dissected as. TLS is a heuristic dissector so should pick up non-standard ports as long as another dissector doesn't get there first. I suspect the HTTP dissector grabbed it first but didn't investigate.
So what does a failed handshake look like, a missing server hello, or something later in the exchange?
( 2021-11-15 08:43:50 +0000 )edit
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2022-08-13 16:19:25
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https://brilliant.org/discussions/thread/method-wanted/
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Method wanted
Consider an $m\times n$ rectangular grid . Find the total number of paths one can reach from lower left corner to upper right corner .
Plz post ur method and other variations possible in such questions,
For example the number of shortest path possible from one corner to opposite corner is $\frac{(m+n)!}{m!\times n!}$
I dont know how to solve if its asked number of paths possible to reach from one corner to the corner above it.
Note by Tanishq Varshney
4 years, 5 months ago
This discussion board is a place to discuss our Daily Challenges and the math and science related to those challenges. Explanations are more than just a solution — they should explain the steps and thinking strategies that you used to obtain the solution. Comments should further the discussion of math and science.
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Assume person starts from lower left corner. To take the shortest path, one can travel only up or right in each step. And there are of course, $m+n$ steps to take. In the end, the person is at the top right corner, this means that he/she has traveled $m$ units up and $n$ units right. The order in which these steps were arranged is the thing that matters here and is the thing we have to count. Basically you need the coefficient of $x^ny^m$ in $(x+y)^{m+n}$.
- 4 years, 5 months ago
if total number of possible paths are asked then??
- 4 years, 5 months ago
Then the answer is infinite, as one can keep going in loops around the grid.
- 4 years, 5 months ago
ok, if one is allowed to move p steps noth and q steps east, then
- 4 years, 5 months ago
I do not understand your question. How is it different from the one initially discussed in this note?
- 4 years, 5 months ago
I mean to say if one has the condition to move 3 steps right and 2 steps up
- 4 years, 5 months ago
It is still no different. If one is forced to move only three steps up, then one can take steps upward which are 3 blocks in size. This is same as saying that the person moves upwards one block when the total number of vertical blocks are divided by three.
eg: if there are thirty vertical blocks and person can take three steps only, this is same as 10 vertical blocks when the person is taking one step each.
- 4 years, 5 months ago
Can u post solution for the problems ants on a cube
- 4 years, 5 months ago
well this set helps a lot
- 4 years, 5 months ago
Yes, I saw that set.. My friend gave me similar qs.. so I din't go for solving them again.
- 4 years, 5 months ago
Staff - 4 years, 5 months ago
it's infinite if you said all path. Obviously, because you told all possible paths, and you can return to a point you started, that makes number of possible paths infinite. What's wrong?
- 4 years, 5 months ago
I think this problem would be more interesting if it asked for the number of ways to reach the opposite square, not being able to retrace your path, i.e. go on squares you have already been on.
- 4 years, 5 months ago
right. I guess that's what meant
- 4 years, 5 months ago
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2019-11-15 14:24:54
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https://de.maplesoft.com/support/help/Maple/view.aspx?path=DataSets/Builtin/WorldMap/SetView
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SetView - Maple Help
DataSets[Builtin][WorldMap]
SetView
specify the view frame for a WorldMap object
Calling Sequence SetView(m,left,bottom,right,top);
Parameters
m - a WorldMap object left, bottom, right, top - the respective edges of the view frame
Description
• The SetView command changes the view frame of m to the specified parameters.
• These parameters correspond to the projected plot coordinates, which vary by projection. Keep this in mind when using this function.
• It is permitted to set the view beyond the maximum extents of the map.
• For some projections, setting the view beyond the regular maximum extents of the map allows the display of another copy of the map to the right of the original copy. This can be useful for, for example, displaying the Pacific Ocean in the center of the map.
Examples
> $m≔\mathrm{DataSets}:-\mathrm{Builtin}:-\mathrm{WorldMap}\left(\right)$
${m}{≔}\left(\begin{array}{cc}\left[{\mathrm{PLOT}}{}\left({\mathrm{...}}\right)\right]& \begin{array}{c}{\mathrm{A map of the world}}\\ {\mathrm{projection: MillerCylindrical}}\end{array}\end{array}\right)$ (1)
> $\mathrm{Display}\left(m\right)$
Display the Pacific Ocean in the center of the map.
> $\mathrm{SetView}\left(m,50,-132,410,132\right):$
> $\mathrm{Display}\left(m\right)$
>
Compatibility
• The DataSets[Builtin][WorldMap][SetView] command was introduced in Maple 2017.
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2023-02-03 13:15:02
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http://ncatlab.org/davidcorfield/show/Modal+logic
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# Contents
## First-order modal logic
Syntactic side: Modal syntactic category in Makkai and Reyes, modal hyperdoctrine, Ghilardi and Meloni?
Semantic side: Metaframes, counterpart frames, coherence frames (Kracht&Kutz, Shehtman/Skvortsov, Shirasu). Where do ionads (Richard Garner) and sheaf semantics (Awodey-Kishida) feature?
In hyperdoctrine picture, on syntax side map type to terminal induces injection of closed sentences into propositions free in variables of type; on semantics side corrsponding map induces fibring of entities of that type over their respective worlds.
Horizontal relations: (a) Awodey-Forssell, (b)??, (c) Dion Coumans slides
Question: Do we gain generality in the top layer, so avoid the need for monadic modalities?
There should be an account of modal homotopy type theory which projects to ordinary modal logic.
Is there some idea with modal type theory to think about its version of the Barcan formula
$\Diamond \exists \to \exists \Diamond?$
For example, we could compare
$\diamond \sum_{x \colon X} A(x)$
and
$\sum_{x \colon X} \Diamond A(x).$
If $\Diamond$ were truncation to Prop, the former is a further projection of the latter, suggesting converse Barcan holds, but Barcan doesn’t.
But it would be nice to illustrate things using the language of possibility. If the dependent type represents players for a Premiership team, we could talk of a possible Premiership player and some Premiership team’s possible player, the latter being more informative as evidence would require that the team be mentioned.
### Blog posts
I, II, III, IV.
Revised on May 24, 2013 12:08:32 by David Corfield (129.12.18.29)
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2014-09-18 19:46:11
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https://www.esaral.com/q/find-the-ratio-in-which-the-line-segment-joining/
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Find the ratio in which the line segment joining
Question.
Find the ratio in which the line segment joining A(1, – 5) and B( – 4, 5) is divided by the x-axis. Also find the coordinates of the point of division.
Solution:
The given points are : A(1, – 5) and B(–4, 5). Let the required ratio = k : 1 and the required point be P(x, y)
Part-I : To find the ratio
Since, the point P lies on x-axis,
$\therefore$ Its $y$-coordinate is 0 .
$x=\frac{m_{1} x_{2}+m_{2} x_{1}}{m_{1}+m_{2}}$ and $0=\frac{m_{1} y_{2}+m_{2} y_{1}}{m_{1}+m_{2}}$
$\Rightarrow x=\frac{-4 k+1}{\mathbf{k}+1}$ and $0=\frac{\mathbf{5 k}-\mathbf{5}}{\mathbf{k}+1}$
$\Rightarrow x(k+1)=-4 k+1$
and $5 \mathrm{k}-5=0 \Rightarrow \mathrm{k}=1$
$\Rightarrow \quad x(k+1)=-4 k+1$
$\Rightarrow x(1+1)=-4+1 \quad[\because k=1]$
$\Rightarrow 2 x=-3$
$\Rightarrow x=-\frac{3}{2}$
$\therefore$ The required ratio $\mathrm{k}: 1=1: 1$
Coordinates of $\mathrm{P}$ are $(\mathrm{x}, 0)=\left(\frac{-\mathbf{3}}{\mathbf{2}}, \mathbf{0}\right)$
Editor
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2022-12-03 08:41:08
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https://brilliant.org/discussions/thread/latex-2/
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# LATEX
I would be grateful if someone could tell me how to use LATEX properly. Thanks
Note by Krishna Ar
4 years, 1 month ago
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paragraph 1
paragraph 2
paragraph 1
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This is a quote
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# up as a code block.
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# up as a code block.
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MathAppears as
Remember to wrap math in $$...$$ or $...$ to ensure proper formatting.
2 \times 3 $$2 \times 3$$
2^{34} $$2^{34}$$
a_{i-1} $$a_{i-1}$$
\frac{2}{3} $$\frac{2}{3}$$
\sqrt{2} $$\sqrt{2}$$
\sum_{i=1}^3 $$\sum_{i=1}^3$$
\sin \theta $$\sin \theta$$
\boxed{123} $$\boxed{123}$$
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@ashutosh mahapatra -Hi! Do you study in Aakash and did they giv you a cash award of 1.6 lacs?
- 3 years, 11 months ago
excuse me ...... i am sorry for my late reply ..........yes I take coaching for medical and they do provide me scholarships
- 3 years, 11 months ago
Daniel's Beginner Latex guide is a good place to start.
Staff - 4 years, 1 month ago
@Calvin Lin - it would be nice if you could do something to my combinatorics rating please.
- 4 years, 1 month ago
You can now view Latex codes by hovering over the equation. Read Seeing actual $$\LaTeX$$ for more details!
This will make it easier to learn how to use Latex.
Staff - 3 years, 6 months ago
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2018-06-22 13:27:07
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https://researchonline.ljmu.ac.uk/id/eprint/10595/
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# The E-MOSAICS project: tracing galaxy formation and assembly with the age-metallicity distribution of globular clusters
Kruijssen, JMD, Pfeffer, JL, Crain, RA and Bastian, N (2019) The E-MOSAICS project: tracing galaxy formation and assembly with the age-metallicity distribution of globular clusters. Monthly Notices of the Royal Astronomical Society. ISSN 0035-8711
Full text not available from this repository. Please see publisher or open access link below:
Open Access URL: https://dx.doi.org/10.1093/mnras/stz968 (Published version)
## Abstract
We present 25 cosmological zoom-in simulations of Milky Way-mass galaxies in the `MOdelling Star cluster population Assembly In Cosmological Simulations within EAGLE' (E-MOSAICS) project. E-MOSAICS couples a detailed physical model for the formation, evolution, and disruption of star clusters to the EAGLE galaxy formation simulations. This enables following the co-formation and co-evolution of galaxies and their star cluster populations, thus realising the long-standing promise of using globular clusters (GCs) as tracers of galaxy formation and assembly. The simulations show that the age-metallicity distributions of GC populations exhibit strong galaxy-to-galaxy variations, resulting from differences in their evolutionary histories. We develop a formalism for systematically constraining the assembly histories of galaxies using GC age-metallicity distributions. These distributions are characterised through 13 metrics that we correlate with 30 quantities describing galaxy formation and assembly (e.g. halo properties, formation/assembly redshifts, stellar mass assembly time-scales, galaxy merger statistics), resulting in 20 statistically (highly) significant correlations. The GC age-metallicity distribution is a sensitive probe of the mass growth, metal enrichment, and minor merger history of the host galaxy. No such relation is found between GCs and major mergers, which play a sub-dominant role in GC formation for Milky Way-mass galaxies. Finally, we show how the GC age-metallicity distribution enables the reconstruction of the host galaxy's merger tree, allowing us to identify all progenitors with masses $M_*\gtrsim10^8$ M$_\odot$ for redshifts $1\leq z\leq2.5$. These results demonstrate that cosmological simulations of the co-formation and co-evolution of GCs and their host galaxies successfully unlock the potential of GCs as quantitative tracers of galaxy formation and assembly.
Item Type: Article This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2019 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. 0201 Astronomical and Space Sciences Q Science > QB AstronomyQ Science > QC Physics Astrophysics Research Institute Oxford University Press Author 25 Apr 2019 08:14 03 Sep 2021 23:42 10.1093/mnras/stz968 https://researchonline.ljmu.ac.uk/id/eprint/10595
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2023-03-25 23:16:54
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https://mathoverflow.net/questions/289356/convex-sets-in-alexandrov-spaces
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# Convex sets in Alexandrov spaces
Let $X$ be a compact Alexandrov space with $curv\geq 1$ (and without boundary). Does $X$ always have a nontrivial compact convex subset without boundary?
Definition of a convex subset: $A\subseteq X$ is called convex if for every two points $p ,q\in A$, there exists a minimizing geodesic between them which is completely in $A$.
This is extremally rare, even if $$X$$ is a Riemannian manifold.
If the convex set $$A$$ has interior points, then any boundary point of the subset $$A$$ in $$X$$ lies on the boundary of Alexandrov space $$A$$. So if $$X\ne A$$ then $$\dim A<\dim X$$.
Note that $$A$$ has to be totally geodesic, otherwise an end of geodesic would be a boundary point of $$A$$. Generic Riemannian manifold do not have totally geodesic submanifolds of dimension at least 2.
So, we are left with the case $$\dim A=1$$. In other words, $$A$$ is a closed geodesic in $$X$$. Since $$A$$ is convex, it has to be length minimizing on each half. This is also extremally rare thing --- generic Riemannian manifold does not have such geodesics.
• @Jayq Both types of boundaries (relative to $X$ and intrinsic boundary of $A$) coincide in this case (since $X$ has no boundary). This is indeed requires a proof, it can be done by induction on dimension; you need to show that space of directions $\Sigma_pA$ forms a closed convex set in $\Sigma_pX$. – Anton Petrunin Dec 27 '18 at 18:39
• This just seems to be true if $A$ is open, or what am I understanding wrong here? Take for example an equator as A inside a round sphere. – Bruce Wayne Mar 5 at 17:12
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2019-10-15 10:13:26
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http://compgroups.net/comp.soft-sys.sas/re-idea-for-a-collaborative-talk-macros-and/1616855
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COMPGROUPS.NET | Search | Post Question | Groups | Stream | About | Register
Re: Idea for a collaborative talk - Macros and Statistic #24
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On Thu, 19 Nov 2009 16:27:52 -0500, Ian Whitlock <iw1sas@GMAIL.COM> wrote:
>Chang,
>I think we pretty much agree, but I couldn't resist embedding some
>below.
>Ian Whitlock
Hi, Ian,
It is great that we agree!!
>***Chang, that is precisely the difference in point of view between a
>good
>programmer and a programming statistician. The latter is more
>interested
>in statistics and the former in the "proper level of generalization". I
>will do anything to get that proper level of generalization.
I have a bit different opinion, probably due to my own experience. My boss
happens to be an accomplished statistician working at the bleeding edge of a
statistical field, but at the same time a great coder who is well versed in
both statistical and general (web and application) programming and is an
expert in many computer languages including C# and R. So, I don't believe
the stereotypes like "statisticians are not good programmers" or
"programmers don't even know what the chi-squared is."
Despite coder's love of "clean" code, software itself does not have any
intrinsic value at all. It is not an art piece, nor a great poem. Its value
lies on what it does when it is run. In this regard, both programmer and
statistician sas users have the same goal -- writing a sas code which does
what they intend it to do. And regardless of their job title, as Peter says,
some people have better skills in coding than others. And everybody will
benefit by learning best practices which are proven to be useful.
....
>> proc logistic ...
>> model dep = ... addvar1;
>> run;
>> model dep = ... addvar2;
>> run;
>> model dep = ... addvar3;
>> run;
>> quit;
>
>***Agreed, but I would have used
Well, this is all rather hypothetical since proc logistic does not allow
multiple model statements. but Peter's statement is rather long because he
didn't take an available shortcut (|). For instance the following two are
the same:
I think the latter seems simple enough to write out in a line. It would have
been better if the model statement understood a naturally briefer notation,
but this does not seem to work.
If there were many control variables, then I would have made a macro
variable at the top like:
%let ctrl = ca cb cc cd ce cf;
and then reference it in the model statements like:
model dep = a|c addvar1|c &ctrl;
model dep = a|c addvar2|c &ctrl;
In the place of title3, Peter could have labeled each model like:
and the output would have been fine without the title3.
The point is that macro's shouldn't be the first choice solution since --
let's be honest -- the mixture of macro and sas code are much more difficult
to read and write than sas code alone. A common sense advice would be: If
you are going to use a proc, then learn about it first -- before you attempt
to "fix" it with macros.
>> /* run the basic model with a different addvar one at a time */
>> title1 "All babies";
>> title2 "basic model: tall = age|weight";
>> ods html;
>> ods graphics on;
>>
>> proc logistic data=class descending;
>> units/default = &units;
>> oddsratio age;
>> oddsratio weight;
>> run;
>> title3;
>>
>> %basicPlusAddvar(c, units=-2*sd -sd sd 2*sd)
>>
>> ods graphics off;
>> ods html close;
>> title;
>
>***I would rate this as a good improvement. On macro style we are in
>agreement.
>On the other hand, how much of Peter's programming time do you
>estimate the
>the development (in this style) would have saved or cost Peter?
Thanks! In terms of cost -- come on -- I rather think this is very cheap to
write and saves a lot of coding. It has no macro statements at all except
%macro and %mend! Hardly no other kinds of macros are easier to write than
this.
>> proc logistic data=class descending;
>> units/default = &units;
>> oddsratio age;
>> oddsratio weight;
>> run;
>> title3;
And, I think this macro makes the code quite clean and easy to read, mainly
because the parts that don't change are abstracted out to a simple (macro)
name, and the parts that change are explicitly shown as parameters. You can
see right away what stays the same and what not.
if you want to, then you can write it as:
but it just repeats the word "addvar".
If the above looks like a wallpaper-y, then I guess one can write another
macro for looping, like:
But a cleaner way to do this is to use a utility macro specialized for
looping along a list of items. Say we have such a macro, say, doOver, then
we can possibly write something like:
%doOver(a b c, exec=%nrstr(
))
Now the-still-open question is whether sas macro is a robust enough language
to write this kind of high-level utility macros. I use the term "high-level"
because this macro takes other macro code as a parameter.
Initially I thought sas macro was robust enough, but currently I am not
In any case, a general utility macros like %doOver() is quite a different
animal all together and should be written with much more general usage in
mind and with a more robust implementation.
I haven't seen enough macro code Peter wrote, so I cannot estimate how long
it will take him to write something like this. On the other hand, I know of
at least two macros already published that can do something similar, so it
may cost him little to download and start using one. If he can trust that
the utility macros are trustworthy, that is. :-)
Cheers,
Chang
0
Reply chang_y_chung (1987) 11/19/2009 11:47:23 PM
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12/9/2013 5:48:03 AM
[PageSpeed]
Hi there, I cannot seem to compile beamerexample-conference-talk in examples/a-conference-talk� with pdflatex from tl2009. I am getting this: ,---- | (./beamerexample-conference-talk.toc) | ! Incompatible list can't be unboxed. | <to be read again> | } | l.99 \end{frame} | | ? ---- Any idea whether this reveals some bugs in beamer and how to fix it? I can, however, go through LaTeX + dvips + pstopdf. Leo Footnotes: � http://latex-beamer.cvs.sourceforge.net/viewvc/latex-beamer/latex-beamer/examples/a-conference-talk/ -- Emacs uptime: 52 days, 6 hours, 18 minutes, 31 seconds � (at) Fri, 13 Nov 2009 15:11:16 +0000, Leo <sdl.web@gmail.com> �crivait (wrote): > I cannot seem to compile beamerexample-conference-talk in > examples/a-conference-talk� with pdflatex from tl2009. > > I am getting this: > > ,---- > | (./beamerexample-conference-talk.toc) > | ! Incompatible list can't be unboxed. > | <to be read again> > | } > | l.99 \end{frame} > | > | ? > ---- > > Any idea whether this reveals some bugs in beamer and how to fix
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2013-12-09 05:48:16
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http://mathoverflow.net/questions/168173/metric-density-theorem-in-most-general-setting
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# Metric density theorem in most general setting?
It's a consequence of Lebesgue's theorem that every measurable $E\subset\mathbb{R}^n$ has a metric density that's $1$ a.e. on $E$ and $0$ a.e. on $\mathbb{R}^n\setminus E$. What are the most general conditions on the measure space for this property to hold?
-
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2015-07-01 12:10:42
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https://math.stackexchange.com/questions/765464/proving-that-s-k-a-subset-mathbbn-a-k-for-k-in-mathbbn-is
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Proving that $S_k = \{A \subset \mathbb{N} : |A| = k\}$ for $k\in\mathbb{N}$ is denumerable. [duplicate]
I am having trouble with this problem for quite some time. I posted this question before but I still can not figure out this problem.
So far,from the suggestion of user134824, I have tried to define an injective function $f$ from $S_k$ to $\mathbb{N}$ as $f_k({n_1,n_2,...n_k})=p_1^{n_1}p_2^{n_2}...p_k^{n_k}$. I am able to prove that this function is injective. However, after this point, I am stuck. I can either prove that $f$ is bijective by proving it is surjective or I can find an injective function $g:\mathbb{N}\rightarrow S_k$ and use the Schroeder-Bernstein theorem.
marked as duplicate by ml0105, Asaf Karagila♦, user99914, user63181, user98602 Apr 23 '14 at 6:55
• What about $g(n) = \{1, 2, ..., n\}$ which is an injective map from $\mathbb{N} \to S_n$ – Mustafa Said Apr 23 '14 at 4:32
• The correct course is not to re-post, but rather to ask for clarification, or edit the previous question to emphasize what you don't understand from the previously given answers. – Asaf Karagila Apr 23 '14 at 4:32
• Sorry, I will not do so in the future. – mrQWERTY Apr 23 '14 at 4:35
Your function $f$ is clearly not surjective, since $p_{k+1}$ (I assume that the $p_k$'s are the sequence of prime numbers) is not in the range of $f$.
However, there are plenty of injections from ${\mathbb N}$ into $S_k$: $g(n)=\{\ n,n+1,\dots,n+k-1\ \}$ for example.
You want to prove that the set of all $k$-sized subsets of $\mathbb N$ is countable (or denumerable if you like).
So the problem is essentially combinatorial. You have $k$ "slots" in which to place a natural number. So in fact, the set of all such $A$ is a subset of $\mathbb N \times \mathbb N \times \dotsc \mathbb N$ (k times). (precisely, it is the subset of this product such that no two numbers are equal. In any case - the product is countable)
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2019-06-26 00:11:08
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https://socratic.org/questions/how-do-you-evaluate-the-integral-int-arctansqrtx
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# How do you evaluate the integral int arctansqrtx?
Jan 15, 2017
$\int \arctan \left(\sqrt{x}\right) \mathrm{dx} = \left(x + 1\right) \arctan \left(\sqrt{x}\right) - \sqrt{x} + C$
#### Explanation:
$I = \int \arctan \left(\sqrt{x}\right) \mathrm{dx}$
Let $t = \sqrt{x}$. Finding $\mathrm{dx}$ in a usable form is simpler if we first write that ${t}^{2} = x$, which then implies that $2 t \mathrm{dt} = \mathrm{dx}$. This way we can plug in $\mathrm{dx}$ into the integral straight away. These substitutions yield:
$I = \int \arctan \left(t\right) \left(2 t \mathrm{dt}\right) = \int 2 t \arctan \left(t\right) \mathrm{dt}$
Now use integration by parts. Let:
$\left\{\begin{matrix}u = \arctan \left(t\right) \text{ "=>" "du=1/(t^2+1)dt \\ dv=2tdt" "=>" } v = {t}^{2}\end{matrix}\right.$
Then:
$I = {t}^{2} \arctan \left(t\right) - \int {t}^{2} / \left({t}^{2} + 1\right) \mathrm{dt}$
Rewriting the integrand as $\frac{{t}^{2} + 1 - 1}{{t}^{2} + 1} = \frac{{t}^{2} + 1}{{t}^{2} + 1} - \frac{1}{{t}^{2} + 1} = 1 - \frac{1}{{t}^{2} + 1}$ we see that
$I = {t}^{2} \arctan \left(t\right) - \left(\int \mathrm{dt} - \int \frac{1}{{t}^{2} + 1} \mathrm{dt}\right)$
Both of which are common integrals:
$I = {t}^{2} \arctan \left(t\right) - t + \arctan \left(t\right) + C$
Returning to $x$ from $t = \sqrt{x}$:
$I = x \arctan \left(\sqrt{x}\right) - \sqrt{x} + \arctan \left(\sqrt{x}\right) + C$
$I = \left(x + 1\right) \arctan \left(\sqrt{x}\right) - \sqrt{x} + C$
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2020-12-05 12:37:16
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http://en.wikipedia.org/wiki/Strong_monad
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In category theory, a strong monad over a monoidal category (C, ⊗, I) is a monad (T, η, μ) together with a natural transformation tA,B : ATBT(AB), called (tensorial) strength, such that the diagrams
, ,
,
and
commute for every object A, B and C (see Definition 3.2 in [1]).
If the monoidal category (C, ⊗, I) is closed then a strong monad is the same thing as a C-enriched monad.
For every strong monad T on a symmetric monoidal category, a costrength natural transformation can be defined by
$t'_{A,B}=T(\gamma_{B,A})\circ t_{B,A}\circ\gamma_{TA,B} : TA\otimes B\to T(A\otimes B)$.
A strong monad T is said to be commutative when the diagram
commutes for all objects $A$ and $B$. [2]
One interesting fact about commutative strong monads is that they are "the same as" symmetric monoidal monads. More explicitly,
• a commutative strong monad $(T,\eta,\mu,t)$ defines a symmetric monoidal monad $(T,\eta,\mu,m)$ by
$m_{A,B}=\mu_{A\otimes B}\circ Tt'_{A,B}\circ t_{TA,B}:TA\otimes TB\to T(A\otimes B)$
• and conversely a symmetric monoidal monad $(T,\eta,\mu,m)$ defines a commutative strong monad $(T,\eta,\mu,t)$ by
$t_{A,B}=m_{A,B}\circ(\eta_A\otimes 1_{TB}):A\otimes TB\to T(A\otimes B)$
and the conversion between one and the other presentation is bijective.
## References
1. ^ Moggi, Eugenio (July 1991). "Notions of computation and monads" (PDF). Information and Computation 93 (1): 55–92. doi:10.1016/0890-5401(91)90052-4.
2. ^ (ed.), Anca Muscholl (2014). Foundations of software science and computation structures : 17th (Aufl. 2014 ed.). [S.l.]: Springer. pp. 426–440. ISBN 978-3-642-54829-1.
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2015-05-30 04:39:14
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https://forums.mirc.com/ubbthreads.php/ubb/printthread/Board/7/main/50682/type/thread
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mIRC Homepage
# mIRC 32bit for wine on Raspbian
Posted By: raven
## mIRC 32bit for wine on Raspbian - 24/11/18 09:57 AM
Don't ask why, but I'm trying to get mIRC to run thru wine in Raspbian (Raspberry Pi OS), but it doesn't like 64bit. I have been googling a bit, but can't try a trustworthy archive of older versions. Is there anyone out there on the interwebz sitting on mIRC 32bit? No matter what version, if it's 1.0 or 7.52, just need to be clean 32bit
Posted By: maroon
7.52 is 32 bits as shown by: //echo -a $bits I'm using 32-bit Windows 7, so if it were 64-bit I couldn't run it. However the mirc.com download page does include a link to v6.35 https://www.mirc.com/get.html "mIRC v6.35 and can be downloaded here." Posted By: raven ## Re: mIRC 32bit for wine on Raspbian - 24/11/18 10:16 AM Originally Posted By: maroon 7.52 is 32 bits as shown by: //echo -a$bits
I'm using 32-bit Windows 7, so if it were 64-bit I couldn't run it.
https://www.mirc.com/get.html
Yes, I know But I probably need a clean 32bit version, without 64bit support for wine to accept it. Allready tried with 6.35
Posted By: Khaled
## Re: mIRC 32bit for wine on Raspbian - 24/11/18 11:02 AM
mIRC is currently 32bit. It performs some 64bit calculations and make some calls that use 64bit values but these are through standard Windows APIs that are not 64bit specific.
As for clean versions of mIRC, that's tricky because I don't have copies of older releases. The only versions I can guarantee are the digitally signed versions from v7.1 onwards. Some websites such as oldversion.com have older versions of mIRC and virus scan them.
I haven't tried Raspberry Pi before - which model are you using?
Posted By: raven
## Re: mIRC 32bit for wine on Raspbian - 24/11/18 11:07 AM
This is an old Raspberry Pi 1, the first model ever produced. I haven't tried on the newer 3 B+ yet, if it's a hardware issue.
Dunno how much Linux you know, but this is the output:
Posted By: Khaled
## Re: mIRC 32bit for wine on Raspbian - 24/11/18 11:15 AM
Interesting, that does look like a 32bit/64bit issue.
If you run the installer on Windows to extract the mirc.exe executable and then try to run that on Raspbian, does it show the same error? Or you could download the latest beta, which is just a zip file containing the mirc.exe executable.
Posted By: raven
## Re: mIRC 32bit for wine on Raspbian - 24/11/18 11:58 AM
Originally Posted By: Khaled
Interesting, that does look like a 32bit/64bit issue.
If you run the installer on Windows to extract the mirc.exe executable and then try to run that on Raspbian, does it show the same error? Or you could download the latest beta, which is just a zip file containing the mirc.exe executable.
I got the exact same issue. Since I'm probably one in 10 million that try to run a modern windows software on an ancient architecture like this, I will post the problem in a few Linux-forums and see if I can find anything there
Posted By: kap
## Re: mIRC 32bit for wine on Raspbian - 24/11/18 02:09 PM
I'm by no means an expert, but I believe this is not possible [1] due to the different CPU architectures. Raspberry pi = ARM/RISC and mIRC runs on x86 architecture...
[1] Unless you pay for something like ExaGear (emulator) https://eltechs.com/product/exagear-desktop/
Posted By: Raccoon
## Re: mIRC 32bit for wine on Raspbian - 24/11/18 11:32 PM
For experimentation, try the 10 year old mIRC v6.35 which is still an official download. If the installer doesn't work in Raspbian, try to just extract the mirc.exe file as that is the only file which is needed to run. (mIRC is very portable in that regard.)
https://www.mirc.com/get.php?version=635
Posted By: KindOne
## Re: mIRC 32bit for wine on Raspbian - 25/11/18 09:39 AM
You would need to run mIRC though an emulator like kap said.
https://www.youtube.com/watch?v=eZuV8oTZiQE (mIRC and Quake on a Pi).
Your PC runs on x86 while the Pi runs on ARM, they are totally different architectures. Basically one speaks English and the other speaks French.
Emulation will be slow on the Pi.
Posted By: Raccoon
## Re: mIRC 32bit for wine on Raspbian - 26/11/18 12:44 AM
He said he's already using Wine, which necessarily means he's already using an x86 emulator to do so. Which means he's probably already running ExaGear (or Qemu).
Posted By: FroggieDaFrog
## Re: mIRC 32bit for wine on Raspbian - 26/11/18 01:06 AM
WINE is not an emulator, its a call translator; it converts Standard Windows API calls to distro-native calls. It does NOT emulate missing feature sets.
Yes, WINE can be installed on a PI but there's not gurantee it will function as expected from a x86 machine on an ARM/RISC machine.
He will need an ARM/RISC to x86 emulator of which to run WINE in.
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2019-10-22 06:24:14
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https://imathworks.com/tex/tex-latex-how-to-insert-slashed-o-o-into-an-authors-name-in-the-bibliography/
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# [Tex/LaTex] How to insert slashed o “ø” into an author’s name in the bibliography
accentsbibliographies
In my bibliography I have a reference to an author with a Danish name: Nørregaard.
The problem is that to do the slashed o I need to type \o. However, I can't do this N\orregaard and if I do this N\o rregaard then I get a space in the name. How do I solve this problem?
#### Best Answer
When typing the name in the text, N\o rregard will not leave any space in the output, as spaces after control sequences (with name consisting of letters) are ignored.
However, in .bib file the question is slightly different, as you want to use the name also for collation. The BibTeX manual recommends
author = {N{\o}rregard, X.}
because in this way the entire combination {\o} would be regarded simply as an "o". The typeset text will not have font dependent kerning between "N" and "ø" and between "ø" and "r". If you're using biblatex, then Nørregard is fine (as long as you use an input encoding where ø is present).
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2023-03-21 21:30:44
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https://msp.org/gt/2012/16-3/b13.xhtml
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#### Volume 16, issue 3 (2012)
1 E J Benveniste, Rigidity of isometric lattice actions on compact Riemannian manifolds, Geom. Funct. Anal. 10 (2000) 516 MR1779610 2 L Burslem, A Wilkinson, Global rigidity of solvable group actions on $S^1$, Geom. Topol. 8 (2004) 877 MR2087072 3 J Cantwell, L Conlon, An interesting class of $C^1$ foliations, Topology Appl. 126 (2002) 281 MR1934265 4 D Damjanović, A Katok, Local rigidity of partially hyperbolic actions I. KAM method and $\mathbb{Z}^k$ actions on the torus, Ann. of Math. 172 (2010) 1805 MR2726100 5 D Fisher, First cohomology and local rigidity of group actions, to appear in Ann. of Math. (2) arXiv:0505520 6 D Fisher, Local rigidity of group actions: past, present, future, from: "Dynamics, ergodic theory, and geometry" (editor B Hasselblatt), Math. Sci. Res. Inst. Publ. 54, Cambridge Univ. Press (2007) 45 MR2369442 7 D Fisher, G Margulis, Almost isometric actions, property (T), and local rigidity, Invent. Math. 162 (2005) 19 MR2198325 8 D Fisher, G Margulis, Local rigidity of affine actions of higher rank groups and lattices, Ann. of Math. 170 (2009) 67 MR2521112 9 N Guelman, I Liousse, Actions of Baumslag–Solitar groups on surfaces arXiv:1004.2126 10 N Guelman, I Liousse, $C^1$–actions of Baumslag–Solitar groups on $S^ 1$, Algebr. Geom. Topol. 11 (2011) 1701 MR2821437 11 A Katok, B Hasselblatt, Introduction to the modern theory of dynamical systems, Encyclopedia of Mathematics and its Applications 54, Cambridge Univ. Press (1995) MR1326374 12 A Katok, J Lewis, Local rigidity for certain groups of toral automorphisms, Israel J. Math. 75 (1991) 203 MR1164591 13 A Katok, R J Spatzier, Differential rigidity of Anosov actions of higher rank abelian groups and algebraic lattice actions, Tr. Mat. Inst. Steklova 216 (1997) 292 MR1632177 14 A E McCarthy, Rigidity of trivial actions of abelian-by-cyclic groups, Proc. Amer. Math. Soc. 138 (2010) 1395 MR2578531 15 A Navas, Groupes résolubles de difféomorphismes de l'intervalle, du cercle et de la droite, Bull. Braz. Math. Soc. 35 (2004) 13 MR2057043 16 V Niţică, A Török, Local rigidity of certain partially hyperbolic actions of product type, Ergodic Theory Dynam. Systems 21 (2001) 1213 MR1849607 17 C Rivas, On spaces of Conradian group orderings, J. Group Theory 13 (2010) 337 MR2653523 18 A Weil, Remarks on the cohomology of groups, Ann. of Math. 80 (1964) 149 MR0169956 19 R J Zimmer, Lattices in semisimple groups and distal geometric structures, Invent. Math. 80 (1985) 123 MR784532
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2022-01-28 19:55:23
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https://cs.stackexchange.com/questions/32153/principles-of-programming-languages-understanding-judgements/32154
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Principles of Programming Languages: Understanding Judgements
I am taking a principles of programming languages class right now and am trying to understand the following judgement form.
n' = -toNumber(v)
------------------
-v --> n'
(Sorry, I can't post pictures yet. And Stack doesn't take LaTeX.) I think it means "n' = -v implies that -v maps to n' " or something along those lines. I guess I really just don't know what the --> means. In math it can either mean "maps to" or "implies" and "maps to" just made more sense.
• also, I didn't really know what else to tag the post with "judgements" and "judgement-form" don't exist.
– steveclark
Oct 19 '14 at 22:49
The --> is the relation that the judgement rules are defining. It's usually pronounced "steps to" or "reduces to". You can think of this relation as the analogue of "showing your work" in algebra:
(1 + 2) * 3 --> 3 * 3 --> 9
It's used as a way of specifying the semantics of a programming language through a binary relation on programs. These kinds of semantics are called small-step semantics. Within small-step semantics, there are approaches include reduction semantics and structural operational semantics. If the program is augmented first to a "configuration" that includes extra components like environments and stores, and the relation is on these configurations instead of just plain program terms, then it's called an abstract machine semantics.
Note: Sometimes you define multiple relations and build up more complicated relations out of them, so you have different arrows.
There are other kinds of operational semantics (eg big-step semantics) and there are other kinds of semantics besides operational semantics.
• Okay, so the relation -v --> n' is saying "-v steps to n prime"? With only one step what is a better way of saying it? Perhaps "-v = n prime"?
– steveclark
Oct 20 '14 at 18:47
• An equivalence relation = relation can be defined as the reflexive-symmetric-transitive closure of -->. But they're different things. There are also big-step relations, usually written with a double down arrow, that are also defined using judgement rules. Also a different thing, although if you have both a small-step and big-step semantics for a language, you might want to prove them equivalent.
– Ryan Culpepper
Oct 20 '14 at 20:15
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2021-09-17 18:34:35
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https://gmatclub.com/forum/how-many-two-digit-whole-numbers-yield-a-remainder-of-1-when-divided-191802.html
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# How many two-digit whole numbers yield a remainder of 1 when divided
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How many two-digit whole numbers yield a remainder of 1 when divided [#permalink]
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How many two-digit whole numbers yield a remainder of 1 when divided by 10 and also yield a remainder of 1 when divided by 6?
A. None
B. One
C. Two
D. Three
E. Four
Kudos for a correct solution.
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Re: How many two-digit whole numbers yield a remainder of 1 when divided [#permalink]
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19 Jan 2015, 06:00
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Bunuel wrote:
How many two-digit whole numbers yield a remainder of 1 when divided by 10 and also yield a remainder of 1 when divided by 6?
A. None
B. One
C. Two
D. Three
E. Four
Kudos for a correct solution.
The possible number N can be written as follow:
N = Multiple of LCM(6,10) + 1st such number
N = 30x + 1
Possible values = 1, 31, 61, 91
Answer : 3 such 2 digit number. D.
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Re: How many two-digit whole numbers yield a remainder of 1 when divided [#permalink]
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19 Jan 2015, 06:01
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Bunuel wrote:
How many two-digit whole numbers yield a remainder of 1 when divided by 10 and also yield a remainder of 1 when divided by 6?
A. None
B. One
C. Two
D. Three
E. Four
Kudos for a correct solution.
n=10p+1 --> Number could be 11 21 31 41 51
n=6q+1 --> Number could be 7 13 19 25 31
n= 30q+31
so n could be 31,61,91
IMO D
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Re: How many two-digit whole numbers yield a remainder of 1 when divided [#permalink]
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20 Jan 2015, 03:13
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Answer = D. Three
LCM of 10 & 6 = 30
Two-digit numbers giving remainder 1 for 30 are
31, 61, 91
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Re: How many two-digit whole numbers yield a remainder of 1 when divided [#permalink]
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20 Jan 2015, 03:21
anupamadw wrote:
Bunuel wrote:
How many two-digit whole numbers yield a remainder of 1 when divided by 10 and also yield a remainder of 1 when divided by 6?
A. None
B. One
C. Two
D. Three
E. Four
Kudos for a correct solution.
n=10p+1 --> Number could be 11 21 31 41 51
n=6q+1 --> Number could be 7 13 19 25 31
n= 30q+31
so n could be 31,61,91
IMO D
Can you explain the highlighted calculation? How is that obtained?
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Re: How many two-digit whole numbers yield a remainder of 1 when divided [#permalink]
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20 Jan 2015, 03:31
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PareshGmat wrote:
anupamadw wrote:
Bunuel wrote:
How many two-digit whole numbers yield a remainder of 1 when divided by 10 and also yield a remainder of 1 when divided by 6?
A. None
B. One
C. Two
D. Three
E. Four
Kudos for a correct solution.
n=10p+1 --> Number could be 11 21 31 41 51
n=6q+1 --> Number could be 7 13 19 25 31
n= 30q+31
so n could be 31,61,91
IMO D
Can you explain the highlighted calculation? How is that obtained?
Positive integer n is divided by 10, the remainder is 1 --> $$n=10q+1$$, where $$q$$ is the quotient --> 1, 11, 21, 31, 41, ...
Positive integer n is divided by 6, the remainder is 1 --> $$n=6p+1$$, where $$p$$ is the quotient --> 1, 7, 13, 19, ...
There is a way to derive general formula for $$n$$ (of a type $$n=mx+r$$, where $$x$$ is divisor and $$r$$ is a remainder) based on above two statements:
Divisor $$x$$ would be the least common multiple of above two divisors 10 and 6, hence $$x=30$$.
Remainder $$r$$ would be the first common integer in above two patterns, hence $$r=1$$.
Therefore general formula based on both statements is $$n=30m+1$$. Thus n could be 1, 31, 61, 91, ... Since n is a two-digit integer, then n could only be 31, 61, or 91.
Check for more here: positive-integer-n-leaves-a-remainder-of-4-after-division-by-93752.html#p721341
Hope it helps.
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Re: How many two-digit whole numbers yield a remainder of 1 when divided [#permalink]
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20 Jan 2015, 04:44
Find the least common factor and multiples of the number +1
Least common factor of 10 and 6 is 30 (two digits multiples of 30 are 30,60,90.. Add +1 to the numbers) so totally 3 numbers are possible
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Re: How many two-digit whole numbers yield a remainder of 1 when divided [#permalink]
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15 Mar 2015, 21:47
hi Bunuel
dont you think with respect to your answer..
since q is the quotient..how can you put q=0 and get 1 as common from both equations
I mean if you put q=0,then n=1 but n is a two digit number so the first common value needs to be 31 i.e N(two digit)=30m+31..
thanks
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Re: How many two-digit whole numbers yield a remainder of 1 when divided [#permalink]
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15 Mar 2015, 22:34
shreygupta3192 wrote:
hi Bunuel
dont you think with respect to your answer..
since q is the quotient..how can you put q=0 and get 1 as common from both equations
I mean if you put q=0,then n=1 but n is a two digit number so the first common value needs to be 31 i.e N(two digit)=30m+31..
thanks
I first found general formula and then applied the restriction.
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Re: How many two-digit whole numbers yield a remainder of 1 when divided [#permalink]
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16 Aug 2017, 09:26
31,61 & 91 are the only three two digit numbers that when divided by 10 and 6 each leaves a remainder of 1.
Option D.
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How many two-digit whole numbers yield a remainder of 1 when divided [#permalink]
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28 Feb 2018, 22:20
Hi All,
This type of question is rooted in pattern-matching. Once you find the patterns behind this question, it won't be hard to solve. Instead of trying to do every step all at once, I suggest that you break the prompt into "pieces":
First, name the 2-digit numbers that are evenly divisible by 10:
10, 20, 30, ......90
Now, name the 2-digit numbers that have a remainder of 1 when divided by 10:
11, 21, 31,.....91
Now that we've established the numbers that fit the first 2 "restrictions" in the prompt, let's factor in numbers that are ALSO divisible by 6:
30, 60, 90
And ALSO have a remainder of 1 when divided by 6:
31, 61, 91
Final Answer:
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Re: How many two-digit whole numbers yield a remainder of 1 when divided [#permalink]
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29 Mar 2018, 23:06
Bunuel wrote:
How many two-digit whole numbers yield a remainder of 1 when divided by 10 and also yield a remainder of 1 when divided by 6?
A. None
B. One
C. Two
D. Three
E. Four
Kudos for a correct solution.
Two digit numbers divided my 10 yielding remainder 1 = 11,21,31,41,51,61,71,81,91
Two digit numbers divided my 6 yielding remainder 1 = 31,61,91
Three common numbers.
Hence (D)
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Re: How many two-digit whole numbers yield a remainder of 1 when divided [#permalink]
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08 Apr 2018, 07:01
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The possible number N can be written as follow:
N = Multiple of LCM(6,10) + 1st such number
N = 30x + 1
Possible values = 1, 31, 61, 91
Answer : 3 such 2 digit number. D.
Re: How many two-digit whole numbers yield a remainder of 1 when divided [#permalink] 08 Apr 2018, 07:01
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# How many two-digit whole numbers yield a remainder of 1 when divided
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Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.
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2018-05-27 05:25:07
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http://karlrosaen.com/ml/learning-log/2016-06-06/
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# KarlRosaen
Transforming random variables, joint and marginal distributions, and The Rule of the Lazy Statistician
## HW on transformation of random variables and joint density functions
I've been catching up on probability homework from chapter 2.
In this problem I had to prove this theorem:
Let $F$ be a cdf, and $U$ a random variable uniformly distributed on $[0, 1]$. Then $F^{-1}(U)$ is a random variable with cdf $F$.
After looking carefully at the definitions of inverse (or quantile) CDFs and reviewing the techniques for how to transform a random variable by applying a function to it, I finally (mostly) got it right before checking with the solution. I wasn't precise in thinking where the resulting random variable was defined, but got the main point. Was a good review of working carefully with the definitions of random variables and cumulative distribution functions.
Let $X$ have a CDF $F$. Find the CDF of $X^+ = \text{max}\{0,X\}$.
was more straight forward and again reviewed the technique of transforming a random variable.
These two problems both concerned joint density functions. In both cases, thinking clearly about how to integrate over 2d regions was the key.
## Marginal Distributions
I read about marginal distributions: you can integrate out a random variable from the joint distribution to get back to a distribution without that variable.
For joint density function $f_{X,Y}$ the marginal density $f_X(x) = \int f(x,y)dy$
In the discrete case, you sum over all values of the variable you are marginalizing.
$f_X(x) = P(X=x) = \sum_y P(X = x, Y = y) = \sum_y f(x,y)$
## Studying Expectation
I began reading ahead into chapter 3 and watching math monk probability videos on expectation. The formulas are pretty straight forward for both the discrete and continuous cases. Some tidbits that were new to me:
• A random variable may not have a well defined expectation
• A random variable may have a well defined infinite expectation
### Well defined
In order to determine whether a distribution is well defined, break it up into $> 0$ and $< 0$ cases (negative and positive parts) and so long as one of them is finite, then the entire summation / integral is "well defined".
An example of a continuous random variable $X$ with an undefined expectation is The Cauchy distribution.
$f(x) = \frac {1}{\pi(1 + x^2)}$
$E(X) = \int_{-\infty}^{\infty} \frac {x}{\pi(1 + x^2)}$
It can be shown that both $\int_{-\infty}^{0} \frac {x}{\pi(1 + x^2)}$ and $\int_{0}^{\infty} \frac {x}{\pi(1 + x^2)}$ are infinite, making the sum of the two undefined. This is a bit hand wavy (see Wikipedia for a more rigorous description), but gives the intuition behind why this integral is undefined: you can't add negative infinity and positive infinity together and have a well defined value.
### Expectation rule aka The Rule of the Lazy Statistician
Another interesting property concerns how to compute the expectation of a function of a random variable.
What if we know $E(X)$ for some density function $f_x(x)$ and for some function $g(x)$ wish to know $E(g(x))$, but don't know $g_x(x)$?
The rule of the Lazy Statistician says we can plug $g(x)$ in for $x$ as follows:
$E(g(x)) = \sum_x g(x) f_X(x)$
and for the continuous case:
$E(g(x)) = \int_{-\infty}^{\infty} g(x) f_X(x) dx$
This seems pretty handy; we know the expected value of uniform distributions, normal distributions and a host of others, so if we would like to find the expected value of a random variable $Y$ with a PDF $f_Y(x)$ that can be re-written as a function of a random variable's PDF that we already know the expected value for, we can go that route without having to compute the integral $\int_{-\infty}^{\infty} x g_X(x) dx$
|
2019-01-22 05:34:34
|
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|
https://electronics.stackexchange.com/questions/542535/buffer-amplifier-and-input-impedance
|
# Buffer amplifier and input impedance
It is said that the input impedance of a buffer must be high enough so that it can isolate its input voltage and carry it to its output for driving purposes.
What I do not understand is why we treat all the independent sources as shorts while calculating input impedance. I know that input impedance is the impedance seen by input voltage present at buffers input.
There is, however, a huge difference between treating independent sources as shorts while calculating input impedance, and not doing so. Someone on this website said you can try finding input impedance without treating independent sources as shorts and get the same result as if you did.
I do not believe that. Can you enlighten me on the use of input impedance and the logic behind its calculation?
Input impedance found by treating sources as shorts cannot be used as an impedance replicate of a circuit connected to some other circuit which we try to solve without writing lots of node equations and therefore has no practical use. Also I looked at posts regarding it on this website and none answered my question.
• During calculation of any input impedance I do not "kill" anything. However, I take into account the fact that the internal resistance of a DC source is zero. That´s all.
– LvW
Jan 14 at 8:08
• "No DC sources were killed in the making of these calculations." Jan 14 at 13:05
• I have always considered it as an application of the principle of superposition: you consider the effect of the 'probing signal' applied to a port, when all other (independent) sources are off. i.e. voltage sources are shorted and current sources are opened. Jan 14 at 13:15
What I do not understand is why we treat all the independent sources as shorts while calculating input impedance.
Hopefully, this answer will make the reason clearer.
Someone on this website said you can try finding input impedance without treating independent sources as shorts and get the same result as if you did.
They are correct.
When we refer to the input impedance of a circuit, we are (almost always) referring to the small signal input impedance. That is, the input impedance gives us the ratio between how much the current will change if we make a small change in input voltage or vice versa.
$$Z_{in} = \frac{\Delta V_{in}}{\Delta I_{in}}$$
or, using the terms of calculus
$$Z_{in} = \frac{dV_{in}}{dI_{in}}$$
If we are given a circuit, such as this:
simulate this circuit – Schematic created using CircuitLab
We can calculate the relationship between the input voltage and the input current as follows.
$$I_{in} = \frac{V_{in} - V_{internal}}{R_{in}}$$
or
$$V_{in} = V_{internal} + R_{in}I_{in}$$
Differentiation gives us
$$Z_{in} = \frac{dV_{in}}{dI_{in}} = \frac{dV_{internal}}{dI_{in}} + \frac{d(R_{in}I_{in})}{dI_{in}} = \frac{dV_{internal}}{dI_{in}} + R_{in}$$
But since $$\V_{internal}\$$ does not depend upon $$\I_{in}\$$,
$$\frac{dV_{internal}}{dI_{in}} = 0$$
So
$$Z_{in} = R_{in}$$
Which is exactly the impedance we would get if we simply treated the voltage source $$\V_{internal}\$$ as a short circuit.
If you understand how this works with one internal resistance and one internal voltage source, then it shouldn't be difficult to see that the same principal applies when there are a network of internal resistances and voltage sources.
The results we get "the long way" is equivalent to simply treating the internal voltage sources as shorts. Since it is also generally quicker to just do the latter, in practice, that is what we generally do. We treat internal voltage sources as shorts when calculating input impedance.
|
2021-10-28 21:06:17
|
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|
http://tex.stackexchange.com/questions/79039/extra-space-between-footnote-numbers-and-content-for-high-count
|
# Extra space between footnote numbers and content for high count
I’m using the following commands to customize footnotes:
\usepackage[bottom,norule,hang]{footmisc}
\setlength{\footnotemargin}{2mm}
\setlength{\footnotesep}{4mm}
The results were as I wanted but only until the 10th footnote (see image below). Is there a way to define the the footnote text margin as a function of the horizontal space that the footnote number takes?
The numbers are flushed to the left and have the same margin as the main text. The footnote text margin, however, seems to be the main text margin plus a fixed quantity.
-
Welcome to TeX.sx! Please add a minimal working example (MWE) that illustrates your problem. knowing what document class you use may be central to answering your question. – barbara beeton Oct 25 '12 at 12:53
footmisc with the hang option has the property that if \footnotemargin is 0 or negative, then the hanging indent is set to the width of the footnote mark. Thus:
\documentclass[a5paper]{article}
\usepackage{lipsum}
\usepackage[bottom,norule,hang]{footmisc}
\setlength{\footnotemargin}{0pt}
\begin{document}
\footnote{Long footnote text, to see whether we get
the hanging effect or not. Just as a test.}\lipsum[4]
\footnote{Long footnote text, to see whether we get
the hanging effect or not. Just as a test.}\lipsum[4]
\setcounter{footnote}{1010}
\footnote{Long footnote text, to see whether we get
the hanging effect or not. Just as a test.}\lipsum[4]
\end{document}
produces the following reasonable effect with no overlapping
What is lacking here is some spacing between the footnote mark and the text. To correct this we can patch the relevant command in footmisc so that if the hang option is given and \footnotemargin is negative, we use the length information there to provide the spacing between the mark and the text, e.g. a value of -0.5em leads to a space of 0.5em. In the original package, if \footnotemargin is <=0 then just the width of the footnotemark is used. Below, we change one line so that the width of a box containing the footnotemark plus a skip of -\footnotemargin is used in the same situation:
\documentclass[a5paper]{article}
\usepackage{lipsum}
\usepackage[bottom,norule,hang]{footmisc}
\setlength{\footnotemargin}{-0.5em}
\makeatletter
\ifFN@para
\else
\long\def\@makefntext#1{%
\ifFN@hangfoot
\bgroup
\setbox\@tempboxa\hbox{%
\ifdim\footnotemargin>0pt
\hb@xt@\footnotemargin{\@makefnmark\hss}%
\else
\@makefnmark\hskip-\footnotemargin %%Changed here
\fi
}%
\leftmargin\wd\@tempboxa
\rightmargin\z@
\linewidth \columnwidth
\parshape \@ne \leftmargin \linewidth
\footnotesize
\@setpar{{\@@par}}%
\leavevmode
\llap{\box\@tempboxa}%
\parskip\hangfootparskip\relax
\parindent\hangfootparindent\relax
\else
\parindent1em
\noindent
\ifdim\footnotemargin>\z@
\hb@xt@ \footnotemargin{\hss\@makefnmark}%
\else
\ifdim\footnotemargin=\z@
\llap{\@makefnmark}%
\else
\llap{\hb@xt@ -\footnotemargin{\@makefnmark\hss}}%
\fi
\fi
\fi
\footnotelayout#1%
\ifFN@hangfoot
\par\egroup
\fi
}
\fi
\makeatother
\begin{document}
\footnote{Long footnote text, to see whether we get
the hanging effect or not. Just as a test.}\lipsum[4]
\footnote{Long footnote text, to see whether we get
the hanging effect or not. Just as a test.}\lipsum[4]
\setcounter{footnote}{1010}
\footnote{Long footnote text, to see whether we get
the hanging effect or not. Just as a test.}\lipsum[4]
\end{document}
-
The only value that is important here, given the hang option, is:
\setlength{\footnotemargin}{2mm}
which is very small for any two digit number. footmisc sets the length to 1.8em by default, which might be too big for your taste unless your footnotes number in the 100s (in my experience, you really need at least 1.2em if you get into the 100s).
Try this file, for example:
\documentclass[12pt]{article}
\usepackage{lipsum}
\usepackage[bottom,norule,hang]{footmisc}
\setlength{\footnotemargin}{1.2em}
%\setlength{\footnotesep}{4mm}
\begin{document}
\setcounter{footnote}{8}
\footnote{Test.}\lipsum[1]
\footnote{Test.}\lipsum[1]
\footnote{Test.}\lipsum[1]
\setcounter{footnote}{98}
\footnote{Test.}\lipsum[1]
\footnote{Test.}\lipsum[1]
\footnote{Test.}\lipsum[1]
\setcounter{footnote}{198}
\footnote{Test.}\lipsum[1]
\footnote{Test.}\lipsum[1]
\footnote{Test.}\lipsum[1]
\setcounter{footnote}{998}
\footnote{Test.}\lipsum[1]
\footnote{Test.}\lipsum[1]
\footnote{Test.}\lipsum[1]
\end{document}
-
Why CW? It seems a genuine personal answer – egreg Oct 25 '12 at 13:06
@egreg -- Hmm, didn't mean to make it CW.... How do I change that? – jon Oct 25 '12 at 13:10
Edit the answer and remove the checkmark at the bottom – egreg Oct 25 '12 at 13:16
@egreg -- I may be too dense, but I made an edit and there was no option to 'uncheck' anything anywhere. Perhaps I don't have the right kind of permissions to make that kind of change..? (Not that I need to undo the CW status, but I agree that it is not a CW answer.) – jon Oct 25 '12 at 13:26
As I know is the usual way to layout footnotes is to have a look to the resulting number of footnotes (for example 105) after you finished writing your text.
Now you can change \setlength{\footnotemargin}{2mm} to a value that gives you the wished space, for example \setlength{\footnotemargin}{7mm}.
So you get all footnotes layouted with the same space for the footnote number.
If you want to change the space after the 9th footnote you can use a second command \setlength{\footnotemargin}{7mm} as shown in the following MWE:
%http://tex.stackexchange.com/questions/79039/extra-space-between-footnote-numbers-and-content-for-high-count
\documentclass[12pt]{scrartcl}
\usepackage[bottom,norule,hang]{footmisc}
\setlength{\footnotemargin}{2mm} % set space for first 9 footnotes
\begin{document}
Lorem ipsum\footnote{footnote 1 now extends footnote now extends footnote now extends
footnote now extends footnote now extends footnote now extends
footnote now extends} below the bottom margin
which\footnote{This footnote 2 now extends} below the bottom margin
which\footnote{This footnote 3 now extends} below the bottom margin
which\footnote{This footnote 4 now extends} below the bottom margin
which\footnote{This footnote 5 now extends} below the bottom margin
which\footnote{This footnote 6 now extends} below the bottom margin
which\footnote{This footnote 7 now extends} below the bottom margin
which\footnote{This footnote 8 now extends} below the bottom margin
which\footnote{This footnote 9 now extends} below the bottom margin
\setlength{\footnotemargin}{7mm} % set new space for number
which\footnote{This footnote 10 now extends footnote now extends
footnote now extends footnote now extends footnote now extends
footnote now extends footnote now extends} below the bottom margin
which\footnote{This footnote 11 now extends} below the bottom margin
which\footnote{This footnote 12 now extends} below the bottom margin
\end{document}
For me that looks not like a good typhography, so I personaly wouldn't do it.
-
|
2014-10-26 05:32:56
|
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|
http://datastrategist.github.io/TileMaker/articles/Intro.html
|
# Meet the Tile
Dashboard Tiles/Notecards are a great way to visualize just one number, and make it big and pretty. They can emphasize results in an easily digestible and colourful format. This package dates back to the days before infoboxes and valueboxes were available from flexdashboard and shinydashboards, and still has some utility today due to it’s flexibility.
This package uses Twitter’s Bootstrap CSS files, and pushes content into buttons that then have different functionality. These buttons are good for embedding in static reports, in Rmd files, and Shiny dashboards. See examples below!
Let’s start small. Note: Please link to References for explanation on full functionality of used tile. (Available if function is underlined/highlighted when hovered over. eg. Hover over ‘solo_box’ below and click. ) Here’s the most basic button:
require(TileMaker) ## to install, use devtools::install_github("DataStrategist/TileMaker")
solo_box(value = 3.3, txt = "Important parameter")
=======
## Overview
Dashboard Tiles, also named Notecards, are a great way to visualize key numbers. They can emphasize results in an easily digestible and colorful format. This package is an alternative to infoboxes and valueboxes available from flexdashboard and shinydashboards.
This package uses Twitter’s Bootstrap CSS files. It pushes the key numbers into buttons using all the functionnality provided by bootstrap. These buttons are good for embedding in static reports, in Rmd files, and Shiny dashboards. See examples below!
## Getting Started
Install the TileMaker package from Github as follows:
# install.packages("TileMaker")
devtools::install_github("DataStrategist/TileMaker")
library(TileMaker)
## Solo Box
The solo_box function allows to create a simple colored box.
solo_box(value = 3.3, txt = "My metric")
The solo_box function only represents one key value. In addition, many feature exist allowing to tune the box entirely.
solo_box(
value = 42, txt = "My metric", former = 99, size = "lg", icon = "check",
type = "warning", link = "https://google.com", units = "kg", hover = "Warning reason", textModifier = "h3"
)
(did you try to hover your mouse over the button?) As you can see, plenty of bells and whistles. Most of the stuff above is pretty intuitive, but let’s explore a bit more, starting with icons (ignore the div_maker for now):
## Icons
div_maker(
subtitle = "One pic is worth a thousand words", textModifier = "h3",
=======
If you rest your mouse over above button, you should see the text “Warning reason” appearing.
Icons
Most of the features above are pretty intuitive. Most favored, icons are also available using Glyphicons.
div_maker(
subtitle = "Icons", textModifier = "h4",
solo_box(value = 3.3, txt = "envelope", icon = "envelope"),
solo_box(value = 3.3, txt = "pushpin", icon = "pushpin"),
solo_box(value = 3.3, txt = "calendar", icon = "calendar")
)
One pic is worth a thousand words
=======
Icons
^ as you can see, we are just using common glyphicons. See the documentation to check your options.
Next, let’s explore the size.
Size
div_maker(
subtitle = "Supersize it!", textModifier = "h3",
=======
Only the name of the icon needs to be supplied, the left hand side of the icon name, “gyphicon-” is automatically managed.
The div_maker functions allows to wrap multiple icons together.
Size
div_maker(
subtitle = "sizes", textModifier = "h4",
solo_box(value = 3.3, txt = "extra small", size = "xs"),
solo_box(value = 3.3, txt = "small", size = "sm"),
solo_box(value = 3.3, txt = "medium", size = "md"),
solo_box(value = 3.3, txt = "large", size = "lg")
)
Supersize it!
=======
sizes
And the type, which dictates the color using the css classes (watch the case sensitivity here!).
Color
div_maker(
subtitle = "... all the colors of a rainbow", textModifier = "h3",
=======
Color
The type argument controls the type of box and dictates the color.
By default, Bootstrap Version 3 is used. 6 types of boxes are available. It can be customised to use boostrap 4.
div_maker(
subtitle = "colors", textModifier = "h4",
solo_box(value = 3.3, txt = "Default", type = "default"),
solo_box(value = 3.3, txt = "Primary", type = "primary"),
solo_box(value = 3.3, txt = "Success", type = "success"),
solo_box(value = 3.3, txt = "Info", type = "info"),
solo_box(value = 3.3, txt = "Warning", type = "warning"),
solo_box(value = 3.3, txt = "Danger", type = "danger")
)
... all the colors of a rainbow
=======
colors
The solo_gradient box automatically changes colors from red to yellow to green based on a target and some thresholds. By default, the target is set to 100 and the thresholds are set to 50 and 90, but obviously those are customizeable.
=======
The solo_gradient_box function allows to automatically pick colors among classic traffic light colors, green-orange-red, and some thresholds. By default, the target is set to 100 and thresholds are set to 50 and 90.
div_maker(
subtitle = "Available gradients", textModifier = "h4",
)
By default, the value is used as the target. It is possible to compare the value to a target using the target argument. The color is then determined by comparing target / value to the thresholds.
div_maker(
subtitle = "Playing with the thresholds", textModifier = "h4",
)
Playing with the thresholds
Arguments thresholdHigh and thresholdLow allow to customise the thresholds.
solo_gradient_box(value = 46, txt = "Customized target<br>and threshold", target = 50, thresholdHigh = 93)
You can see that the box changes to orange since it’s now between thresholdHigh and thresholdLow.
The <br> element above forces a line break. Text accepts full html code, natively written.
The multi_box, in contrast to the solo_box, takes multiple values in one button, providing an easy way to summarize a ton of information in one button.
=======
Multi Box
The multi_box function takes multiple values in one button, providing an easy way to summarize a ton of information in one button.
multi_box(values = c(4, 5, 6), txt = c("Sally", "George", "Mohammed"), icons = c("check", "plus", "calendar"), title = "Candidates")
Last but not least, here’s the tile_matrix
=======
Tile Matrix
The tile_matrix function creates several new solo_gradient_boxes and compiles them all into a grid.
suppressPackageStartupMessages(library(dplyr))
#> Warning: package 'dplyr' was built under R version 3.5.2
df <- data_frame(
values = c(2, 5, 6),
txt = c("Sally", "George", "Mohammed")
)
#> Warning: data_frame() is deprecated, use tibble().
#> This warning is displayed once per session.
tile_matrix(df, values = values, txt = txt, target = 10, thresholdHigh = 60, thresholdLow = 40, textModifier = "h2")
The function takes a dataframe as first value and as such can be used in a tidyverse pipe.
Example:
mtcars %>%
# name of car model is contained in the rowname
mutate(names = rownames(.)) %>%
tile_matrix(
values = "disp", txt = "names",
target = 500, thresholdHigh = 80, thresholdLow = 50
)
The concept of the tile_matrix is to provide a quick way to visualize simple informations. The fact that the thresholds scale automatically to the target is useful, since one need only set the target in order to quickly obtain actionable information.
For example, if one wanted to quickly see diamond prices:
library(ggplot2)
#> Warning: package 'ggplot2' was built under R version 3.5.2
diamonds %>%
group_by(color) %>%
summarize(price = mean(price)) %>%
## Assume there was some former price that was a bit different
mutate(old_price = price * (1 * runif(n = 7, min = -.2, max = .5))) %>%
tile_matrix(data = ., values = price, txt = color, former = old_price, target = 5000, roundVal = 0)
So we’ve seen this former value a few times now, but what does it do? Simply put it contextualizes the displayed value in comparision with a former value. This is especially useful to measure performance increase or declines. In order to show the functionality, let’s use a quite contrived scenario:
suppressPackageStartupMessages(library(dplyr))
df <- data_frame(
values = seq(from = 0, to = 100, by = 10),
txt = "comparison to 50",
former = 50
)
## Let's pretend that all previous values were 50... so:
tile_matrix(data = df, values = values, txt = txt, former = former)
Grammar of tile_maker
Buttons are put into a div (which is more or less an html “row”… kinda). And these divs are put into a finalizer.
=======
The former argument contextualizes the displayed value in comparison with a former value. This is especially useful to measure growth of a metric.
Grammar of tile_maker
Buttons are put into a div tag and final values are put into a finalizer.
Value1 <- 88
Value2 <- 1985
Value3 <- 1.22
Value4 <- 30
Value5 <- 42
## Make the buttons how you like
Button1 <- solo_box(value = Value1, txt = "Speed", units = "mph", type = "danger")
Button2 <- solo_box(value = Value2, txt = "Origin", type = "warning", icon = "flash")
value = Value3, txt = "Powah", units = "GW", hover = "Great Scott!",
target = 1.22, thresholdHigh = 100, thresholdLow = 99
)
Button4 <- solo_box(value = Value4, txt = "Heads turned", units = "K", type = "info")
Button5 <- solo_box(
value = Value5, txt = "Answer", hover = "Whales rule. Petunias suck",
link = "https://en.wikipedia.org/wiki/The_Hitchhiker%27s_Guide_to_the_Galaxy", type = "primary"
)
## Combine in 2 rows:
Div1 <- div_maker(subtitle = "Future", textModifier = "h2", Button1, Button2, Button3)
Div2 <- div_maker(subtitle = "Effect", textModifier = "h2", Button4, Button5)
## Now put them all together:
finisher(
title = "Important block", css = "https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css",
file = NULL, textModifier = "h1", div_maker(subtitle = "Boom", textModifier = "hi",Div1, Div2)
)
Important block
Boom
Future
Effect
These functions are included to help with inclusion in different document types and for testing small snipets of code.
It’s not working / you broke my entire report / help
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2021-08-04 08:07:54
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https://www.numerade.com/questions/factor-each-polynomial-if-a-polynomial-cannot-be-factored-write-prime-factor-out-the-greatest-com-19/
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### Factor each polynomial. If a polynomial cannot be…
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Problem 19
Factor each polynomial. If a polynomial cannot be factored, write prime. Factor out the greatest common factor as necessary.
$$24 a^{4}+10 a^{3} b-4 a^{2} b^{2}$$
$24 a^{4}+10 a^{3} b-4 a^{2} b^{2}=(4 a-b)(3 a+2 b)$
## Discussion
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## Video Transcript
you asked a factor. This train a meal here, The first thing we d'oh is try to see if there is a common factor between all three terms. So you can see that all three terms with the fact Arata too. And we can fact you're in a square. So once that's factored out, we're left with 12 a squared plus five a b and the last term we're left with two be squared. So we're gonna write the to a squared and then we will look at this train a meal here. So from here, this is a train all meal where the leading coefficient is not one. So what we need to do is we need to multiply the leading coefficient with what would be the constant trip. So that would be p 12. And then that would be the negative, too. So if you multiply them together, we end up with negative 24. So now, identifying two factors of 24 that multiply together to be negative 24 and add together to be positive five. So that'll be a negative three positive eight. So that means we can rewrite our try no meal, and then we'll split up the five baby into positive, ate a B and negative three a B, and we'll look at it to terms at a time. So from 12 a score and the a t A B, we can't factor out for a, which means we're left with three a plus two B and now from these two terms, we can factor out a negative B and we're left with three A plus two B Once we've done that. Well, look at thes two terms and they both have the factor. Three A. Plus two b So that means we have three a plus two B as a contractor, and that means we're left with four A minus beak. And since multiplication is associative, we don't need the big rackets. We could just rewrite this as to a squared times three a plus two B times for a minus 60
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2020-08-07 15:25:36
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http://math.stackexchange.com/questions/52338/conformal-maps-onto-the-unit-disc-in-mathbbc/52358
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# Conformal Maps onto the Unit Disc in $\mathbb{C}$
I am interested in finding explicit formulae for (better yet characterizing) conformal functions from various domains onto the open unit disc $\mathbb{D}\subset\mathbb{C}$, and in understanding the key ideas necessary to establish such functions.
Specifically, what can $f$ look like when $f:G\to\mathbb{D}$ is conformal and
(1) $G=\{x+iy~|~x,y>0\}$ is the open first quadrant.
(2) $G=\{x+iy~|~x>0,~0<y<1\}$ is an open horizontal strip in the first quadrant.
(3) $G=\{z\in\mathbb{C}~|~\frac{1}{2}<|z|<1\}$ is an annulus.
(4) $G=\mathbb{D}\cap\{|z-\frac{1}{2}|>\frac{1}{2}\}$ is something else (torus?).
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Do you want these to be bijective? By "conformal" some people mean "biholomorphic", and others mean "holomorphic with non-vanishing derivative". – Dylan Moreland Jul 19 '11 at 5:51
not necessarily, but it would be nice to also know when/if this is possible. The definition of conformal I was introduced to was "angle-preserving" which was shown to require non-vanishing derivative (Are these conditions equivalent for holomorphic functions?). This was what I had in mind, but all discussion is welcome. – RHP Jul 19 '11 at 5:55
Sure. I must run off, but I'll mention that I often find the Cayley transform to be useful for problems like this. Here it would be helpful for (1). – Dylan Moreland Jul 19 '11 at 6:01
@RHP: Thanks, great to hear! As for $3$, the point is that the annulus has a hole, while the disk doesn't have one. If you want a biholomorphic map, you need the same number of holes, intuitively. By the way, one can show (not easy!) that if you have an annulus with radii $0 \lt r \lt R$ and you want to map it to another annulus with radii $0 \lt r' \lt R'$ then you must have $\frac{R}{r} = \frac{R'}{r'}$ "the ratio of radii of annuli is a conformal invariant", (this is such a strange sentence that you can't forget it). I like Ahlfors a lot (but it's tough) and ... – t.b. Jul 19 '11 at 22:44
...for historical remarks (and many other things) I recommend the great books by Remmert Part 1 and Part 2. I worked through them in German, but I guess the English editions aren't too different. Cartan is great and I have some prejudices against Lang, but that's a matter of taste, I guess :) I never looked at Nevanlinna. – t.b. Jul 19 '11 at 22:48
Since you didn't show too many own thoughts, here are some hints only. By conformal I understand biholomorphic.
1. First take $f(z) = z^2$ to map the quadrant biholomorphically onto the upper half-plane, then compose with the Cayley transform $\kappa(z) = \frac{z-i}{z+i}$ to get $\kappa(f(z)) = \frac{z^2-i}{z^2+i}$.
2. Look at $\cos{(z)}$ and modify appropriately.
3. Impossible, since $G$ is not simply connected.
4. Map the region $G$ to the strip between two parallel lines using a Möbius transformation sending $1$ to infinity (e.g. using the inverse Cayley transformation). Then use the exponential function.
This should be enough to figure the solutions out.
For the precise relationship between "conformal" and "analytic", as well as for explanations on how to find such maps, I refer you to Ahlfors or (probably—I never really read it) Needham or any decent text on complex analysis treating conformal mapping.
The characterization of biholomorphisms between simply connected regions is essentially the content of the Riemann mapping theorem.
Sometimes biholomorhic mappings between polygonal regions and the unit disk can be computed via the Schwarz-Christoffel formula, but usually it leads to elliptic integrals that can't be solved explicitly in elementary terms.
Since the solution of 4. is a bit trickier, here's a rather detailed outline:
First note that $G$ is the region enclosed between the circles $\{|z| = 1\}$ and $\{|z - \frac{1}{2}| = \frac{1}{2}\}$. Applying the Möbius transformation (= the inverse Cayley transform) $\kappa^{-1}(z) = i\frac{1+z}{1-z}$ sends $G$ to the horizontal strip $\{0 \lt \operatorname{Im}{z} \lt 1\}$. To see this, look at this picture from Wikipedia illustrating the Cayley transform:
Finally, the exponential function $g(z) = \exp{(\pi z)}$ sends this strip to the upper half plane. Composing this with the Cayley transform we get the biholomorphic map $h = \kappa \circ g \circ \kappa^{-1}: G \to \mathbb{D}$.
-
Here is a sketch:
For (1) we want to map the open first quadrant onto the unit disk. What we can do is first map the open first quadrant onto the upper half plane then the upper half plane onto the unit disk. the mapping $z \mapsto z^2$ maps the first quadrant to the upper half plane. Then the upper half plane can be mapped to the unit disk by the mapping $z \mapsto \frac{z-i}{z+i}$. What remains to do is to compose.
For (2) $z \mapsto cosh(\pi z)$ maps the open half strip of width 1 to the upper half plane. You can now compose with the mapping in (1) which maps the upper half plane to the unit disk.
EDIT: As noted by Theo, these two last examples are false.
For (3) I am not so sure. $z \mapsto lnz$ maps an annulus onto a rectangle. A rectangle in the plane is simply connected so by the Riemann Mapping Theorem one can find a unique conformal mapping between the rectangle and the unit disk. However I don't know which one.
For (4) It sound like the region described in the interior of a parabola. In which the case the mapping onto the unit disk would be $tan^2 \frac{\pi}{4} \sqrt{\frac{z}{p}}$, $p$ being one fourth of the height of the segment on the $y$-axis formed by the intersection of the parabola with the $y$-axis. I am really unsure about this last one. Maybe someone else could help.
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Your solutions to 3) and 4) are wrong. In 3) the map is not everywhere defined, in 4) you have the difference between two circles (precisely the region inside the unit disk but outside the circle with radius $1/2$ around $1/2$. – t.b. Jul 19 '11 at 7:48
Thanks! I'll edit accordingly. – user786 Jul 19 '11 at 7:53
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2014-10-25 01:56:28
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https://www.sarthaks.com/101453/define-an-irrational-number
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# Define an irrational number.
1.1k views
Define an irrational number.
by (22.3k points)
selected
A number which can neither be expressed as a terminating decimal nor as a repeating decimal is called an irrational number.For example, 1.01001000100001…
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2021-10-15 22:54:28
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https://chemistry.meta.stackexchange.com/questions/4124/wrong-alternative-invocation-of-mathjax
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# Wrong alternative invocation of MathJax
It is commonly known that MathJax can be invoked with $...$ for inline mode and $$...$$ for display mode.
The more latex-like invocation would be $$...$$ for inline mode and $...$ for display mode. This does not work as backslashes and brackets have a special meaning on stack exchange and often need to be escaped.
According to the site's config, there are other invocations allowed:
tex2jax: { inlineMath: [ ["$", "$"], ["\\$","\$/extract_itex]"] ], displayMath: [ ["",""], ["\\[", "\$"] ],
processEscapes: true, ignoreClass: "tex2jax_ignore|dno" }
This literally means that \\$....\$/extract_itex] and \\[...\$ will also invoke MathJax. I think the first definition is faulty and should rather be $...$.
P.S.: All of the posts using this construct (4; cleaned now) are false positives, therefore these alternative invocations are not used at all. Is there any reason to keep them? Alternatively (or additionally), one could add \\ce{...} (or better \ce{...}, like \ref{...} see below)[1] to invoke MathJax - that would probably make more sense.
Additional notes:
1. processRefs: true is the default, so \eqref{label} or \ref{label} works automatically (see sandbox).
Setting up direct rendering of \ce{...} can probably not be handled in the configuration file in this style, this has to be treated directly by the pre-processor. Therefore this would be a feature-request that needs to be relegated to the MathJax team. However, while \ref only processes a label, which should only be a string, and therefore the regular expression \(eq)?ref{[^}]*} is completely sufficient, that cannot be said for all of the code that mhchem's \ce{...} may be able to process.
2. processEnvironments: true is the default, so something like \begin{align}...\end{align} will also invoke maths mode. (\begin{align}...\end{align} is possible in MathJax, but would be an error in latex. It also is really terrible, as it sets a display style environment in inline mode.)
• Right. They should be swapped\\\\\\\\replaced. – M.A.R. ಠ_ಠ Feb 13 '18 at 6:54
• \\ce{H2O} --> $\ce{H2O}$ would be awesome! It doesn't work currently, but it'd be great if it did :D – Gaurang Tandon Feb 13 '18 at 9:22
• As far as readability goes while typing or editing, or searching for a specific line, I think is superior to \( analogues and bare commands. Not sure why \\$ has been used though. Does indeed seem inconsistent at first glance. – Linear Christmas Feb 13 '18 at 12:42 • @LinearChristmas I find \( increases readability and avoids misinterpretation, since the beginning of maths mode is clearly marked. You have a lot of ambiguity with (which is usually disabled in default mode for that reason). I guess the "bug" is due to the fact that the forward slash needs to be escaped on SE, because it is used to escape. It is a simple typo, I believe. – Martin - マーチン Feb 13 '18 at 12:51 • Currently, there preview editor only looks for and (or \ on some sites) for math delimiters, so if you use \\( or \\[, the contents of the math is not protected from the Markdown processing, and may prevent the math from displaying, or require additional backslashes to be escape Markdown syntax. So the preview code would need to be modified to support \\( and \\[. Similarly for \ce. – Davide Cervone Feb 13 '18 at 13:43 • I assume the reason that dollar signs were used in preference to \( and \[ is the interaction between Markdown's use of with that of MathJax. For example, since [ is used in Markdown to create links, if you wanted an explicit [ in your output, you are supposed to use \[. That conflicts with using \[ as the display-math delimiter. – Davide Cervone Feb 13 '18 at 13:47 • @Davide If the editor only looks for and , then wouldn't it be better to completely remove the alternate stuff. It wouldn't really make a difference in the usage (at least not here). The way it is now is just very confusing and I don't see any benefit. the \ce might be better implemented in the MathJax source analogous to \ref; it wouldn't be much of a gain if you had to write \\\\ce... – Martin - マーチン Feb 13 '18 at 14:24 • @Martin-マーチン, I agree, the configuration is inappropriate. I'm only saying that more has to be done to allow \\( and \\[ than just changing the configuration parameter. I am in favor of removing those from the configuration entirely. Yes, it would be possible to handle \ce as \ref currently is, but again, there need to be other changes that support that (this time changes to MathJax itself). If those changes were done, you would only need \ce not \\\\ce. – Davide Cervone Feb 13 '18 at 14:43 • @Davide I have tested \\[ and \\\\( and they do work as they are expected on our site, see sandbox demo. Whatever is going on under the hood, I don't know. However, while removing them on this site is no problem, if that is a network wide configuration, then more care must be applied. The thing about \ce is unfortunately not as easy as \ref as the former takes code, the latter only a string (the preprocessor uses a regex that would break at }), and an implementation must be handled in the source there, so I'm cutting this here. – Martin - マーチン Feb 14 '18 at 3:58 • @Martin-マーチン, yes, if you use them, they will "work", in the sense that MathJax will process them (both in the page and in the preview), but the system goes to special lengths to protect the contents of math delimited by dollar signs from being modified by Markdown, whereas it doesn't do that for these other delimiters. For example, if you enter \\\\(x _1 + x_ 2\\$ you will get \$x 1 + x 2\$, (italic 1 + x with math not processed). Or if you do something like \\$x[1](lost)\\$, you will get no brackets or parens and without "lost". – Davide Cervone Feb 14 '18 at 10:34 • So you have to be careful about the math you type within those delimiters in ways that you don't with dollar delimiters. – Davide Cervone Feb 14 '18 at 10:38 • @Davide Thank yo so much for clearing that up. I think I understand it better now. I'm not a programmer, so that helps a lot. – Martin - マーチン Feb 14 '18 at 10:54 • @Martin-マーチン Are the current mathjax site settings the reason why \begin{align}...\end{align} works just as well with or without the \$ signs? – Gaurang Tandon Mar 12 '18 at 14:44
• @GaurangTandon the current settings allow environments to be escaped; I think the developers did consider this option when they enabled it. See 2 in additional notes – Martin - マーチン Mar 12 '18 at 15:35
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2019-07-18 01:06:30
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https://www.mentis.de/browse?et=journal&lang=en&level=all&pageSize=10&sort=datedescending&subSite=bdm
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History of Philosophy & Logical Analysis (HPLA) holds that the goal of systematic philosophy of uncovering and substantiating philosophical truths should also be a central tenet when investigating the history of philosophy, especially considering that historical texts were written with this goal in mind, i.e., out of an interest in truth. For this reason we should read these texts as potential conveyors of truths, and if — despite benevolent interpretation — this proves to be unfeasible, then as conveyors of falsehoods. Only in this manner can a lively dialogue with our philosophical past be initiated, and only thus can we properly pay tribute to it. On the whole, this approach promises to shed new light on classical texts, making them even more fruitful in dealing with the controversial issues of modern philosophy.
HPLA provides a forum for articles in which texts from the history of philosophy are approached with the aim of offering a systematic reconstruction of theories concerning pertinent philosophical problems (often deploying the resources of modern logical analysis in the course of reconstruction). Discovered theories or fragments of such theories can be carefully elucidated and developed further. In this way, novel questions can be put to an historical author, and profitably pursued within the framework of the established system.
The works of the history of philosophy should not only be honoured as historical documents, but first and foremost be taken seriously from a philosophical point of view.
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2022-08-19 10:37:16
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http://physics.qandaexchange.com/?qa=2463/series-inductor-needed-for-an-arc-lamp-to-operate
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# Series inductor needed for an arc lamp to operate
52 views
An arc lamp requires a direct current of 10A and 80V to function.If it is connected to 220 V (rms) ,50 Hz AC supply the series inductor needed for it to work is close to:
A) 0.08 H
B) 0.044 H
C) 0.065 H
D) 80 H
Since the frequency is less I thought that it is simply an output of a rectifier consisting of AC ripples.The DC component of the rectifier I thought was the average value of AC ripples which is $200 \sqrt 2 * \frac{2}{\pi}$ and the resistance of inductor is $2\pi f L$ So since inductor is connected in series to the load resistance current through inductor is 10A . Hence $$10=\frac{\text{average voltage or dc voltage}}{\text{inductor reactance}}$$ This gives me an answer of 0.065 H
However I am not sure the method I adopted is correct because I am taking capacitance reactance in DC voltage which should be zero.
asked Mar 20, 2018
The question does not mention a DC rectifier, so you should not assume one is used. The question does not explain how the arc lamp works, but I would assume that a minimum amount of power is required. What inductance is required to deliver the same power?
1 vote
The question does not mention a DC rectifier, so you should not assume one is used. The question does not explain how the arc lamp works, but I would assume that it is a resistor and that a minimum amount of power is required for it to work.
Using DC, the arc lamp dissipates a power of $P=I^2 R$. Its resistance is $R=\frac{80V}{10A}=8\Omega$.
Using AC the arc lamp dissipates a power of $P=I_{rms}^2 R$. The power dissipated will be the same as when using DC provided that $I_{rms}=I=10A$, because the resistance remains the same.
The impedance of the RL circuit is
$|Z|=\frac{V_{rms}}{I_{rms}}=\frac{220V}{10A}=22\Omega$
$Z$ is related to $R, \omega, L$ by
$Z=R+j\omega L$
$|Z|^2=R^2+(\omega L)^2$
Therefore
$\omega L=\sqrt{|Z|^2-R^2} \approx 20.494 \Omega$
$L\approx \frac{20.494}{2 \pi 50} \approx 0.06523 H$
|
2019-03-21 11:41:55
|
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|
https://www.vedantu.com/question-answer/the-number-of-solutions-in-x-in-02pi-for-which-class-12-maths-cbse-5f5f71259427543f91c6d32b
|
Question
# The number of solutions in $x \in [0,2\pi ]$ for which $|\sqrt {2{{\sin }^4}x + 18{{\cos }^2}x} - \sqrt {2{{\cos }^4}x + 18{{\sin }^2}x} | = 1$ isA) 4B) 2C) 6D) 8
Hint: This is a particular problem of trigonometry where we have to all the value of $x \in [0,2\pi ]$
So we first solve modulus function so if $|x| = a$ then it become $x = \pm a$ and we use some trigonometric relation
$1.{\cos ^2}x - {\sin ^2}x = \cos 2x$
$2.{\sin ^2}x + {\cos ^2}x = 1$ and we rearrange the whole equation by squaring both sides and after that we use these formulas to find our answer.
Step 1. Solve modulus function first
$\sqrt {2{{\sin }^4}x + 18{{\cos }^2}x} - \sqrt {2{{\cos }^4}x + 18{{\sin }^2}x} = \pm 1$
Now doing rearrangements we get
$\sqrt {2{{\sin }^4}x + 18{{\cos }^2}x} = \pm 1 + \sqrt {2{{\cos }^4}x + 18{{\sin }^2}x}$
Now by taking square both side we get
${(\sqrt {2{{\sin }^4}x + 18{{\cos }^2}x} )^2} = {( \pm 1 + \sqrt {2{{\cos }^4}x + 18{{\sin }^2}x} )^2}$
Now ${(a \pm b)^2} = {a^2} + {b^2} \pm 2ab$
By using this we can write
$2{\sin ^4}x + 18{\cos ^2}x = 1 + 2{\cos ^4}x + 18{\sin ^2}x \pm 2\sqrt {2{{\cos }^4}x + 18{{\sin }^2}x}$
Now rearranging this equation
$2{\sin ^4}x - 2{\cos ^4}x + 18{\cos ^2}x - 18{\sin ^2}x = 1 \pm 2\sqrt {2{{\cos }^4}x + 18{{\sin }^2}x}$
Now use some formula
${a^2} - {b^2} = (a - b)(a + b)$ and ${\cos ^2}x - {\sin ^2}x = \cos 2x$
From this we get
$2({\sin ^2}x - {\cos ^2}x)({\sin ^2}x + {\cos ^2}x) + 18({\cos ^2}x - {\sin ^2}x) = 1 \pm 2\sqrt {2{{\cos }^4}x + 18{{\sin }^2}x}$
As we know ${\sin ^2}x + {\cos ^2}x = 1$
Now $- 2\cos 2x + 18\cos 2x = 1 \pm 2\sqrt {2{{\cos }^4}x + 18{{\sin }^2}x}$
From this we can write
$16\cos 2x = 1 \pm 2\sqrt {2{{\cos }^4}x + 18{{\sin }^2}x}$
Now we use $2{\cos ^2}x = 1 + \cos 2x$ and $2{\sin ^2}x = 1 - \cos 2x$
$16\cos 2x = 1 \pm 2\sqrt {\dfrac{1}{2}{{(\cos 2x + 1)}^2} + 9(1 - \cos 2x)}$
Now again we do rearrangements of terms
$16\cos 2x - 1 = \pm 2\sqrt {\dfrac{1}{2}{{(\cos 2x + 1)}^2} + 9(1 - \cos 2x)}$
Now take square both side
${(16\cos 2x - 1)^2} = 4\{ \dfrac{1}{2}({\cos ^2}2x + 1 + 2\cos 2x) + 9 - 9\cos 2x\}$
Now open square and multiply 4 inside the curly braces
$256{\cos ^2}2x + 1 - 32\cos 2x = 2{\cos ^2}2x + 2 + 4\cos 2x + 36 - 36\cos 2x$
Now after rearranging we get
$254{\cos ^2}2x = 37$
We can write this as
$\cos 2x = \pm \sqrt {\dfrac{{37}}{{254}}}$
Now
$2x = {\cos ^{ - 1}}( \pm \sqrt {\dfrac{{37}}{{254}}} )$
$x = \dfrac{1}{2} \times {\cos ^{ - 1}}( \pm \sqrt {\dfrac{{37}}{{254}}} )$ And
Now as question said $x \in [0,2\pi ]$
In this interval $\cos x$ take two time negative value and two time positive value
When $x \in \left[ {0,\dfrac{\pi }{2}} \right]$ , $\cos x$ take positive value so here $x = \dfrac{1}{2} \times {\cos ^{ - 1}}\left( {\sqrt {\dfrac{{37}}{{254}}} } \right)$
When $x \in \left[ {\dfrac{\pi }{2},\pi } \right]$, $\cos x$ take negative value so here $x = \dfrac{1}{2} \times {\cos ^{ - 1}}\left( { - \sqrt {\dfrac{{37}}{{254}}} } \right)$
And also when $x \in \left[ {\pi ,\dfrac{{2\pi }}{3}} \right]$, $\cos x$ take positive value so here $x = \dfrac{1}{2} \times {\cos ^{ - 1}}\left( {\sqrt {\dfrac{{37}}{{254}}} } \right)$
And also when $x \in \left[ {\dfrac{{2\pi }}{3},2\pi } \right]$, $\cos x$ take negative value so here $x = \dfrac{1}{2} \times {\cos ^{ - 1}}\left( { - \sqrt {\dfrac{{37}}{{254}}} } \right)$
From this we can say total 4 solution we have in $x \in \left[ {0,2\pi } \right]$
Note: We have to remember that $\cos \theta$ taking positive value in first and fourth coordinate and negative value in second and third coordinate.
|
2020-09-20 12:05:47
|
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|
https://zbmath.org/serials/?q=se%3A451
|
# zbMATH — the first resource for mathematics
## Indiana University Mathematics Journal
Short Title: Indiana Univ. Math. J. Publisher: Indiana University, Department of Mathematics, Bloomington, IN ISSN: 0022-2518 Online: http://www.iumj.indiana.edu/IUMJ/issues.php Predecessor: Journal of Mathematics and Mechanics Comments: Indexed cover-to-cover; Partly indexed as: Math. J., Indiana Univ.
Documents Indexed: 3,607 Publications (since 1970) References Indexed: 223 Publications with 6,415 References.
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Large stable pulse solutions in reaction-diffusion equations. Zbl 0994.35058
Doelman, Arjen; Gardner, Robert A.; Kaper, Tasso J.
2001
Convex functions of a measure and applications. Zbl 0581.46036
Demengel, F.; Temam, R.
1984
Nerve axon equations. III: Stability of the nerve impulse. Zbl 0245.92004
Evans, John W.
1972
Spectral properties of an acoustic boundary condition. Zbl 0325.35060
Beale, J. Thomas
1976
Two notes on reductions of ideals. Zbl 0368.13003
Ratliff, L. J. jun.; Rush, David E.
1978
Uniqueness of unbounded viscosity solution of Hamilton-Jacobi equations. Zbl 0551.49016
Ishii, Hitoshi
1984
Estimates for the heat kernel for a sum of squares of vector fields. Zbl 0639.58026
Jerison, David S.; Sánchez-Calle, Antonio
1986
Variable Hardy spaces. Zbl 1311.42053
Cruz-Uribe, David; Wang, Daniel
2014
Nonlinear potential analysis on Morrey spaces and their capacities. Zbl 1100.31009
2004
The smoothness of solutions to nonlinear variational inequalities. Zbl 0278.49011
Brézis, Haïm; Kinderlehrer, David
1974
On the global well-posedness of the Boussinesq system with zero viscosity. Zbl 1178.35303
Hmidi, Taoufik; Keraani, Sahbi
2009
Upper bounds on the number of determining modes, nodes, and volume elements for the Navier-Stokes equations. Zbl 0796.35128
Jones, Don A.; Titi, Edriss S.
1993
An integral inequality for compact spacelike hypersurfaces in de Sitter space and applications to the case of constant mean curvature. Zbl 0677.53067
Montiel, Sebastián
1988
Best constants for Moser-Trudinger inequalities on the Heisenberg group. Zbl 1019.43009
Cohn, William S.; Lu, Guozhen
2001
Convex solutions to nonlinear elliptic and parabolic boundary value problems. Zbl 0481.35024
Korevaar, Nicholas J.
1983
Two weighted inequalities for potential and fractional type maximal operators. Zbl 0809.42007
Pérez, Carlos
1994
Compact, nuclear, and Hilbert-Schmidt composition operators on H$$^2$$. Zbl 0276.47037
Shapiro, J. H.; Taylor, P. D.
1973
$$Q$$ spaces of several real variables. Zbl 0984.46020
Essén, Matts; Janson, Svante; Peng, Lizhong; Xiao, Jie
2000
Cusp and $$b_1$$ growth for ball quotients and maps onto $$\mathbb{Z}$$ with finitely generated kernel. Zbl 07360761
Stover, Matthew
2021
Khovanov homology and periodic links. Zbl 07360762
Borodzik, Maciej; Politarczyk, Wojciech
2021
The Landis conjecture with sharp rate of decay. Zbl 1467.35119
Rossi, Luca
2021
Hyperbolic free boundary problems and applications to wave-structure interactions. Zbl 1467.35360
Iguchi, Tatsuo; Lannes, David
2021
Boolean extremes and Dagum distributions. Zbl 07360773
Garza Vargas, Jorge; Voiculescu, Dan Virgil
2021
On superspecial abelian surfaces and type numbers of totally definite quaternion algebras. Zbl 07360779
Xue, Jiangwei; Yu, Chia-Fu
2021
Minimal elastic networks. Zbl 1455.74033
Acqua, Anna Dall’; Novaga, Matteo; Pluda, Alessandra
2020
On the upper regularity dimensions of measures. Zbl 1439.28011
Fraser, Jonathan; Howroyd, Douglas
2020
Serrin’s problem and Alexandrov’s soap bubble theorem: enhanced stability via integral identities. Zbl 1445.35257
Magnanini, Rolando; Poggesi, Giorgio
2020
The inner structure of boundary quotients of right LCM semigroups. Zbl 1467.46057
Aiello, Valeriano; Conti, Roberto; Rossi, Stefano; Stammeier, Nicolai
2020
Metric methods for heteroclinic connections in infinite dimensional spaces. Zbl 1445.35156
Monteil, Antonin; Santambrogio, Filippo
2020
Orbit equivalence and classification of weak solenoids. Zbl 1460.37026
Hurder, Steven; Lukina, Olga
2020
Signature and concordance of virtual knots. Zbl 07310879
Boden, Hans; Chrisman, Micah; Gaudreau, Robin
2020
On a relation between harmonic measure and hyperbolic distance on planar domains. Zbl 07293627
Karafyllia, Christina
2020
On conormal and oblique derivative problem for elliptic equations with Dini mean oscillation coefficients. Zbl 1459.35119
Dong, Hongjie; Lee, Jihoon; Kim, Seick
2020
Nash multiplicity sequences and Hironaka’s order function. Zbl 07293631
Bravo, Ana; Pascual-Escudero, Beatriz; Encinas, S.
2020
Global attractors for the Benjamin-Bona-Mahony equation with memory. Zbl 1439.35081
Dell’oro, Filippo; Goubet, Olivier; Mammeri, Youcef; Pata, Vittorino
2020
Quantitative stability for hypersurfaces with almost constant mean curvature in the hyperbolic space. Zbl 1447.53050
Ciraolo, Giulio; Vezzoni, Luigi
2020
Hessian valuations. Zbl 1445.26011
Colesanti, Andrea; Ludwig, Monika; Mussnig, Fabian
2020
Singular values and non-repelling cycles for entire transcendental maps. Zbl 07293619
Benini, Anna Miriam; Fagella, Núria
2020
Groupoids and $$C^*$$-algebras for left cancellative small categories. Zbl 1467.46053
Spielberg, Jack
2020
Analysis of hyper-singular, fractional, and order-zero singular integral operators. Zbl 07293629
Chaffee, Lucas; Hart, Jarod; Oliveira, Lucas
2020
Conformal volume and eigenvalue problems. Zbl 1455.58011
Kokarev, Gerasim
2020
Critical Fujita exponents for semilinear heat equations with quadratically decaying potential. Zbl 1455.35012
Ishige, Kazuhiro; Kawakami, Tatsuki
2020
Modulus of families of sets of finte perimeter and quasiconformal maps between metric spaces of globally Q-bounded geometry. Zbl 1439.30089
Jones, Rebekah; Lahti, Panu; Shanmugalingam, Nageswari
2020
A decomposition by non-negative functions in the Sobolev space $$W^{k,1}$$. Zbl 1453.46033
Ponce, Augusto; Spector, Daniel
2020
Complex symmetric composition operators induced by linear fractional maps. Zbl 1444.47041
Gao, Yong-Xin; Zhou, Ze-Hua
2020
Stability of periodic waves in Hamiltonian PDEs of either long wavelength or small amplitude. Zbl 1450.35055
Benzoni-Gavage, S.; Mietka, C.; Rodrigues, L. M.
2020
On the general dual Orlicz-Minkowski problem. Zbl 07197979
Xing, Sudan; Ye, Deping
2020
Functional calculus of operators with heat kernel bounds on non-doubling manifolds with ends. Zbl 1439.42015
Bui, The Anh; Duong, X. T.; Li, Ji; Wick, Brett
2020
Two-weight $$L^p \to L^q$$ bounds for positive dyadic operators in the case $$0 < q < 1 \leq p < \infty$$. Zbl 1439.42028
Hanninen, Timo; Verbitsky, Igor E.
2020
Julia Robinson numbers and arithmetical dynamic of quadratic polynomials. Zbl 1458.11152
Castillo, Marianela; Vidaux, Xavier; Videla, Carlos
2020
A theorem for random Fourier series on compact quantum groups. Zbl 07199850
Youn, Sang-Gyun
2020
Stochastic Navier-Stokes-Fourier equations. Zbl 1452.35265
Breit, Dominic; Feireisl, Eduard
2020
Sufficiently collapsed irreducible Alexandrov 3-spaces are geometric. Zbl 1460.53041
Galaz-Garcia, Fernando; Guijarro, Luis; Nunez-Zimbron, Jesus
2020
On Bloom-type estimates for iterated commutators of fractional integrals. Zbl 1444.42019
Accomazzo, Natalia; Martínez-Perales, Javier C.; Rivera-Ríos, Israel P.
2020
Rectifiability and approximate differentiability of higher order for sets. Rectifiability and approximate differentiability of higher order for sets. Zbl 1426.28010
Santilli, Mario
2019
Dissipative reaction diffusion systems with quadratic growth. Zbl 1418.35237
Pierre, Michel; Suzuki, Takashi; Yamada, Yoshio
2019
Simple transitive 2-representations via (co)algebra 1-morphisms. Zbl 07083343
Mackaay, Marco; Mazorchuk, Volodymyr; Miemietz, Vanessa; Tubbenhauer, Daniel
2019
Optimal domain spaces in Orlicz-Sobolev embeddings. Zbl 1440.46028
Cianchi, Andrea; Musil, Vit
2019
Global solutions and ill-posedness for the Kaup system and related Boussinesq systems. Zbl 1439.35389
Ambrose, David; Bona, Jerry; Milgrom, Timur
2019
Monotonicity of non-pluripolar Monge-Ampère masses. Zbl 1422.32041
Nyström, David Witt
2019
Totally real embeddings with prescribed polynomial hulls. Zbl 1429.32018
Arosio, Leandro; Wold, Erlend Fornaess
2019
Parabolic equations with divergence-free drift in space $$L_t^\ell L_x^q$$. Zbl 1423.35142
Qian, Zhongmin; Xi, Guangyu
2019
Zeros of real random polynomials spanned by OPUC. Zbl 1433.30019
Yattselev, Maxim; Yeager, Aaron
2019
Stationary solution to the Navier-Stokes equations in the scaling invariant Besov space and its regularity. Zbl 1428.35298
Kaneko, Kenta; Kozono, Hideo; Shimizu, Senjo
2019
Stationary solutions for stochastic damped Navier-Stokes equations in $$\mathbb{R}^d$$. Zbl 1445.76060
Brzeźniak, Zdisław; Ferrario, Benedetta
2019
The dynamics of quasiregular maps of punctured space. Zbl 1428.37044
Nicks, Daniel A.; Sixsmith, David J.
2019
Rigidity results for variational infinity ground states. Zbl 1429.35104
Crasta, Graziano; Fragalà, Ilaria
2019
Smoothing for the fractional Schrödinger equation on the torus and the real line. Zbl 1416.35291
Erdoğan, M. Burak; Gürel, T. Burak; Tzirakis, Nikolaos
2019
Equivariant APS index for Dirac operators of non-product type near the boundary. Zbl 1422.19002
Braverman, Maxim; Maschler, Gideon
2019
Opening the Maslov box for traveling waves in skew-gradient systems: counting eigenvales and proving (in)stability. Zbl 1442.35208
Cornwell, Paul
2019
Quantum groups with partial commutation relations. Zbl 1454.46069
Speicher, Roland; Weber, Moritz
2019
Matrix weighted Poincaré inequalities and applications to degenerate elliptic systems. Zbl 1433.42012
Isralowitz, Joshua; Moen, Kabe
2019
On formation of singularity of the full compressible magnetohydrodynamic equations with zero heat conduction. Zbl 1433.76189
Zhong, Xin
2019
Global solutions to a class of two-dimensional Riemann problems for the Euler equations with a general equation of state. Zbl 1435.35246
Lai, Geng
2019
The defect of Bennequin-Eliashberg inequality and Bennequin surfaces. Zbl 1426.57010
Ito, Tetsuya; Kawamuro, Keiko
2019
Concentration phenomena in an integro-PDE model for evolution of conditional dispersal. Zbl 1429.35126
Hao, Wenrui; Lam, King-Yeung; Lou, Yuan
2019
On a Monge-Ampère operator for plurisubharmonic functions with analytic singularities. Zbl 1439.32079
Andersson, Matts; Blocki, Zbigniew; Wulcan, Elizabeth
2019
Locator function for concentration points in a spatially heterogeneous semilinear Neumann problem. Zbl 1422.35061
Takagi, Izumi; Yamamoto, Hiroko
2019
Product Hardy, BMO spaces and iterated commutators associated with Bessel Schrödinger operators. Zbl 1422.42031
Betancor, Jorge J.; Duong, Xuan Thinh; Li, Ji; Wick, Brent D.; Yang, Dongyong
2019
The tangency of a $$C^1$$ smooth submanifold with respect to a non-involutive $$C^1$$ distribution has no superdensity points. Zbl 1427.58001
2019
Variance of the volume of random real algebraic submanifolds. II. Zbl 1440.53067
Letendre, Thomas; Puchol, Martin
2019
Inner amenability and approximation properties of locally compact quantum groups. Zbl 1464.46072
Crann, Jason
2019
Heteroclinic traveling fronts for reaction-convection-diffusion equations with a saturating diffusive term. Zbl 1448.34094
Garrione, Maurizio; Strani, Marta
2019
Global $$L^q$$ Gevrey functions, Paley-Wiener theorems, and the FBI transform. Zbl 1426.42019
Hoepfner, Gustavo; Raich, Andrew
2019
The Diederich-Fornaess index and good vector fields. Zbl 1435.32043
Harrington, Phillip S.
2019
On the elliptic Stark conjecture at primes of multiplicative reduction. Zbl 07137162
Casazza, Daniele; Rotger, Victor
2019
An implosion arising from saddle connection in 2D complex dynamics. Zbl 1422.32023
Inou, Hiroyuki; Nakane, Shizuo
2019
Arcs on spheres intersecting at most twice. Zbl 1429.57009
Smith, Christopher; Przytycki, Piotr
2019
Intersection properties of stable subgroups and bounded cohomology. Zbl 07083349
Antolín, Yago; Mj, Mahan; Sisto, Alessandro; Taylor, Samuel J.
2019
A non-commutative unitary analogue of Kirchberg’s conjecture. Zbl 1433.46033
Harris, Samuel J.
2019
Bergman kernel asymptotics for singular metrics on punctured Riemann surfaces. Zbl 1429.32004
Coman, Dan; Klevtsov, Semyon; Marinescu, George
2019
On convergence of oscillatory ergodic Hilbert transforms. Zbl 1423.42013
Krause, Ben; Lacey, Michael; Wierdl, Mate
2019
Relating properties of crossed products to those of fixed point algebras. Zbl 1454.46063
Pasnicu, Cornel; Phillips, Christopher
2019
Regularity and long-time behavior for a thermodynamically consistent model for complex fluids in two space dimensions. Zbl 1439.35395
Eleuteri, Michela; Gatti, Stefania; Schimperna, Giulio
2019
The Cauchy-Leray integral: counter-examples to the $$L^p$$-theory. Zbl 1439.32009
Lanzani, Loredana; Stein, Elias
2019
Asymptotic and viscous stability of large-amplitude solutions of a hyperbolic system arising from biology. Zbl 1402.35286
Martinez, Vincent R.; Wang, Zhian; Zhao, Kun
2018
Banach-valued multilinear singular integrals. Zbl 1416.42013
Di Plinio, Francesco; Ou, Yumeng
2018
Assouad-type spectra for some fractal families. Zbl 1407.28002
Fraser, Jonathan M.; Yu, Han
2018
Asymptotic behavior of the powers of composition operators on Banach spaces of holomorphic functions. Zbl 06971428
Arendt, Wolfgang; Chalendar, Isabelle; Kumar, Mahesh; Srivastava, Sachi
2018
Nonlocal shape optimization via interactions of attractive and repulsive potentials. Zbl 1402.49033
Burchard, Almut; Choksi, Rustum; Topaloglu, Ihsan
2018
The domain of parabolicity for the Muskat problem. Zbl 1402.35318
Escher, Joachim; Matioc, Bogdan-Vasile; Walker, Christoph
2018
Effects of large degenerate advection and boundary conditions on the principal eigenvalue and its eigenfunction of a linear second-order elliptic operator. Zbl 1410.35089
Peng, Rui; Zhou, Maolin
2018
On the topological degree of the mean field equation with two parameters. Zbl 1405.35041
Jevnikar, Aleks; Wei, Juncheng; Yang, Wen
2018
A “liquid-solid” phase transition in a simple model for swarming, based on the “no flat-spots” theorem for subharmonic functions. Zbl 1420.49040
Frank, Rupert; Lieb, Elliott H.
2018
Some quasilinear elliptic equations involving multiple $$p$$-Laplacians. Zbl 1417.35048
Pomponio, Alessio; Watanabe, Tatsuya
2018
Weighted norm inequalities for integral transforms. Zbl 1410.42013
Gorbachev, Dmitry; Liflyand, Elijah; Tikhonov, Sergey
2018
A Jones slopes characterization of adequate knots. Zbl 1417.57014
Kalfagianni, Efstratia
2018
Conformal curvature flows on compact manifold of negative Yamabe constant. Zbl 1401.53049
Chen, Xuezhang; Ho, Pak Tung
2018
Existence and structure of minimizers of least gradient problems. Zbl 1402.49008
2018
Triebel-Lizorkin spaces on metric spaces via hyperbolic fillings. Zbl 1412.42058
Bonk, Mario; Saksman, Eero; Soto, Tomás
2018
Bifurcation and nonnegative solutions for problems with mean curvature operator on general domain. Zbl 1420.35101
Dai, Guowei
2018
Compactly supported stationary states of the degenerate Keller-Segel system in the diffusion-dominated regime. Zbl 1428.35618
Carrillo, José A.; Sugiyama, Yoshie
2018
The Maslov and Morse indices for system Schrödinger operators on $$\mathbb{R}$$. Zbl 1408.53106
Howard, P.; Latushkin, Y.; Sukhtayev, A.
2018
Hulls of surfaces. Zbl 1417.32009
Izzo, Alexander J.; Stout, Edgar Lee
2018
Weighted estimates for bilinear fractional integral operators and their commutators. Zbl 1417.42016
Hoang, Cong; Moen, Kabe
2018
Stability of standing waves for logarithmic Schrödinger equation with attractive delta potential. Zbl 1442.35428
Pava, Jaime Angulo; Ardila, Alex Hernandez
2018
Immersed concordance of links and Heegaard Floer homology. Zbl 1407.57005
Borodzik, Maciej; Gorsky, Eugene
2018
Continuity results for TV-minimizers. Zbl 1408.49038
Mercier, Gwenael
2018
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#### Cited by 24,229 Authors
133 Wei, Juncheng 126 Yang, Dachun 75 Vazquez, Juan Luis 73 Zumbrun, Kevin R. 70 de Lima, Henrique F. 64 Mu, Chunlai 62 Feireisl, Eduard 58 Jørgensen, Palle E. T. 55 Lu, Guozhen 55 Papageorgiou, Nikolaos S. 54 Ding, Yong 54 Rossi, Julio Daniel 54 Titi, Edriss Saleh 53 Kenig, Carlos Eduardo 53 Yang, Tong 52 Caffarelli, Luis Ángel 52 Cianchi, Andrea 49 Yuan, Wen 48 Lions, Pierre-Louis 47 Friedman, Avner 47 Xiao, Jie 46 Lu, Shanzhen 46 Xin, Zhouping 44 Pistoia, Angela 43 Guo, Boling 42 Carrillo de la Plata, José Antonio 42 Del Pino, Manuel A. 42 Do Ó, João M. Bezerra 42 Giga, Yoshikazu 41 Popescu, Gelu 41 Zhao, Huijiang 40 Lin, Chang-Shou 39 Sawano, Yoshihiro 39 Souganidis, Panagiotis E. 39 Souplet, Philippe 39 Wu, Huoxiong 39 Xue, Qingying 38 Byun, Sun-Sig 38 Novaga, Matteo 38 Strichartz, Robert S. 37 Kukavica, Igor 37 Perthame, Benoît 37 Xi, Lifeng 37 Yin, Zhaoyang 36 Kozono, Hideo 36 Musso, Monica 36 Schechter, Martin 35 Dancer, Edward Norman 35 de la Llave, Rafael 35 Dolbeault, Jean 35 Lau, Kasing 35 Ruf, Bernhard 34 Peletier, Lambertus Adrianus 34 Raeburn, Iain 34 Velásquez, Marco Antonio Lázaro 34 Zhu, Changjiang 33 Dong, Hongjie 33 Garofalo, Nicola 33 Guo, Zongming 33 Lasserre, Jean-Bernard 33 Maz’ya, Vladimir Gilelevich 33 Tang, Xianhua 33 Valdinoci, Enrico 33 Vasseur, Alexis F. 32 Chen, Gui-Qiang G. 32 Du, Lili 32 Galaktionov, Victor Aleksandrovich 32 Ishii, Hitoshi 32 Koskela, Pekka 32 Li, Wan-Tong 32 Malchiodi, Andrea 32 Mitrea, Marius 32 Ni, Wei-Ming 32 Nyström, Kaj 31 Barles, Guy 31 Foiaş, Ciprian Ilie 31 Miyagaki, Olimpio Hiroshi 31 Shivaji, Ratnasingham 31 Yang, Yunyan 30 Barbu, Viorel 30 Dutkay, Dorin Ervin 30 Felli, Veronica 30 Hofmann, Steve 30 Ishige, Kazuhiro 30 Sims, Aidan 30 Wu, Jiahong 29 Duong, Xuan Thinh 29 Lieberman, Gary M. 29 Masmoudi, Nader 29 Miao, Changxing 29 Novotný, Antonín 29 Zhong, Chengkui 28 Agarwal, Ravi P. 28 Chen, Yanping 28 Constantin, Peter 28 Lasiecka, Irena 28 Morgan, Frank 28 Ngai, Sze-Man 28 Quaas, Alexander 28 Rauch, Jeffrey B. ...and 24,129 more Authors
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#### Cited in 868 Journals
2,064 Journal of Mathematical Analysis and Applications 1,795 Journal of Differential Equations 1,333 Journal of Functional Analysis 1,098 Nonlinear Analysis. Theory, Methods & Applications. Series A: Theory and Methods 1,075 Transactions of the American Mathematical Society 1,069 Proceedings of the American Mathematical Society 679 Archive for Rational Mechanics and Analysis 653 Calculus of Variations and Partial Differential Equations 581 Communications in Partial Differential Equations 561 Advances in Mathematics 482 The Journal of Geometric Analysis 454 Mathematische Annalen 432 Communications in Mathematical Physics 421 Mathematische Zeitschrift 369 Nonlinear Analysis. Theory, Methods & Applications 366 Integral Equations and Operator Theory 355 Annales de l’Institut Henri Poincaré. Analyse Non Linéaire 354 Journal of Mathematical Physics 353 Discrete and Continuous Dynamical Systems 306 Journal de Mathématiques Pures et Appliquées. Neuvième Série 290 Annali di Matematica Pura ed Applicata. Serie Quarta 249 Journal d’Analyse Mathématique 243 Applicable Analysis 234 Acta Mathematica Sinica. English Series 233 SIAM Journal on Mathematical Analysis 231 Duke Mathematical Journal 223 Physica D 223 Proceedings of the Royal Society of Edinburgh. Section A. Mathematics 218 Linear Algebra and its Applications 211 Israel Journal of Mathematics 207 Nonlinear Analysis. Real World Applications 207 Comptes Rendus. Mathématique. Académie des Sciences, Paris 203 Manuscripta Mathematica 201 ZAMP. Zeitschrift für angewandte Mathematik und Physik 192 Mathematical Methods in the Applied Sciences 190 Potential Analysis 188 Communications on Pure and Applied Analysis 184 Complex Variables and Elliptic Equations 179 The Journal of Fourier Analysis and Applications 176 Rocky Mountain Journal of Mathematics 167 Applied Mathematics and Computation 166 Applied Mathematics Letters 162 Science China. Mathematics 161 Inventiones Mathematicae 160 Communications in Contemporary Mathematics 156 Annales de l’Institut Fourier 152 Mathematische Nachrichten 150 Journal of Mathematical Sciences (New York) 148 Journal of Mathematical Fluid Mechanics 141 Revista Matemática Iberoamericana 140 Computers & Mathematics with Applications 139 Complex Analysis and Operator Theory 138 Bulletin of the Australian Mathematical Society 137 Annali della Scuola Normale Superiore di Pisa. Classe di Scienze. Serie IV 137 Monatshefte für Mathematik 137 Abstract and Applied Analysis 134 Journal of Approximation Theory 134 NoDEA. Nonlinear Differential Equations and Applications 134 Boundary Value Problems 129 Journal of Inequalities and Applications 128 Annals of Global Analysis and Geometry 126 Arkiv för Matematik 124 Journal of Dynamics and Differential Equations 123 Stochastic Processes and their Applications 123 European Series in Applied and Industrial Mathematics (ESAIM): Control, Optimization and Calculus of Variations 122 Discrete and Continuous Dynamical Systems. Series B 119 M$$^3$$AS. Mathematical Models & Methods in Applied Sciences 117 Journal of Algebra 117 International Journal of Mathematics 116 Journal of Geometry and Physics 116 Journal of Computational and Applied Mathematics 115 Results in Mathematics 112 Differential Geometry and its Applications 111 Ergodic Theory and Dynamical Systems 111 Acta Applicandae Mathematicae 110 Tohoku Mathematical Journal. Second Series 108 Communications on Pure and Applied Mathematics 108 Archiv der Mathematik 105 Topology and its Applications 105 Journal of Nonlinear Science 104 Geometriae Dedicata 104 Journal of Evolution Equations 103 Mathematical Proceedings of the Cambridge Philosophical Society 103 Nonlinearity 97 Advanced Nonlinear Studies 96 Mathematical Notes 95 Chinese Annals of Mathematics. Series B 94 Journal of Statistical Physics 91 Journal of Function Spaces 90 Applied Mathematics and Optimization 90 Journal of the European Mathematical Society (JEMS) 90 Journal of Hyperbolic Differential Equations 87 Fractals 86 Czechoslovak Mathematical Journal 85 Chaos, Solitons and Fractals 82 Journal für die Reine und Angewandte Mathematik 80 Siberian Mathematical Journal 80 Probability Theory and Related Fields 78 Communications in Algebra 77 Acta Mathematica ...and 768 more Journals
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#### Cited in 63 Fields
16,546 Partial differential equations (35-XX) 4,781 Operator theory (47-XX) 4,432 Functional analysis (46-XX) 3,548 Fluid mechanics (76-XX) 3,090 Differential geometry (53-XX) 2,597 Harmonic analysis on Euclidean spaces (42-XX) 2,092 Dynamical systems and ergodic theory (37-XX) 2,076 Global analysis, analysis on manifolds (58-XX) 2,061 Calculus of variations and optimal control; optimization (49-XX) 1,827 Probability theory and stochastic processes (60-XX) 1,748 Several complex variables and analytic spaces (32-XX) 1,693 Measure and integration (28-XX) 1,690 Ordinary differential equations (34-XX) 1,654 Functions of a complex variable (30-XX) 1,084 Numerical analysis (65-XX) 1,049 Real functions (26-XX) 996 Biology and other natural sciences (92-XX) 958 Potential theory (31-XX) 757 Mechanics of deformable solids (74-XX) 671 Statistical mechanics, structure of matter (82-XX) 621 Quantum theory (81-XX) 566 Approximations and expansions (41-XX) 552 Systems theory; control (93-XX) 531 Manifolds and cell complexes (57-XX) 519 Convex and discrete geometry (52-XX) 500 Linear and multilinear algebra; matrix theory (15-XX) 431 Topological groups, Lie groups (22-XX) 428 Algebraic geometry (14-XX) 428 Integral equations (45-XX) 383 Abstract harmonic analysis (43-XX) 371 Mechanics of particles and systems (70-XX) 362 General topology (54-XX) 325 Number theory (11-XX) 323 Game theory, economics, finance, and other social and behavioral sciences (91-XX) 315 Operations research, mathematical programming (90-XX) 309 Associative rings and algebras (16-XX) 285 Combinatorics (05-XX) 275 Classical thermodynamics, heat transfer (80-XX) 258 Commutative algebra (13-XX) 243 Difference and functional equations (39-XX) 233 Optics, electromagnetic theory (78-XX) 217 Group theory and generalizations (20-XX) 202 Algebraic topology (55-XX) 198 Relativity and gravitational theory (83-XX) 183 Integral transforms, operational calculus (44-XX) 180 Computer science (68-XX) 171 Geophysics (86-XX) 158 Special functions (33-XX) 150 Information and communication theory, circuits (94-XX) 132 Statistics (62-XX) 120 Nonassociative rings and algebras (17-XX) 113 Category theory; homological algebra (18-XX) 94 Geometry (51-XX) 90 $$K$$-theory (19-XX) 79 Mathematical logic and foundations (03-XX) 66 Order, lattices, ordered algebraic structures (06-XX) 56 Astronomy and astrophysics (85-XX) 45 Field theory and polynomials (12-XX) 44 General and overarching topics; collections (00-XX) 41 History and biography (01-XX) 28 Sequences, series, summability (40-XX) 7 General algebraic systems (08-XX) 3 Mathematics education (97-XX)
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2021-09-19 19:37:57
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https://tex.stackexchange.com/questions/299793/how-to-insert-picture-here
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# How to insert picture here?
I want text to flow picture, as it is in the book:
And with advice of @Johannes_B I did it with help of minipage, but It doesn't suit me at all things.
1. See this. First page of my document. Do you see that it is wrong?
2. I want to insert Pictures always on the outer side of the page! but this will do it never.
3. How to add mechanism of solving this problem to my super function of adding pictures. (Before this problem it solved all my problems, in lists, environments, items, etc)
4. # WHY WITH POWER OF LATEX NOBODY KNOWS HOW TO INSERT PICTURE IDEALLY IN ANY SUTIATION?!
like Office 2014 - just press one button.
I don't believe that all of latex users do a lot of manual work when try to insert a picture. But I have been trying to do it for three weeks!
I have 2 hundread pictures to insert in my book, and if I will try to insert it manually , I'll go crazy!
I am really shocked, that there are a lot of sutiations when nothing works.
\documentclass{book}
\usepackage{graphicx}
\usepackage{mwe}
\usepackage{amsmath}
\usepackage{microtype}
\usepackage{caption}
\input{insbox.tex}
\usepackage{threeparttable}
\usepackage{changepage}
\usepackage{xargs}
\usepackage[showframe]{geometry}
\usepackage{printlen}
\newtheorem{thm}{Theorem}
\newcounter{ct}
\newlength\imageheight
\newcount\narrowlinect
\narrowlinect=0\relax
\newcounter{pictnumber}
\newcommand*{\wrapitem}{\apptocmd{\labelenumi}{\hskip\leftmargin}{}{}\item\apptocmd{\labelenumi}{\hskip-\leftmargin}{}{}}
%
\newcommandx{\InsertPictL}[4][1=0,3=0]{\refstepcounter{pictnumber}%
\settoheight\imageheight{\includegraphics[width=#4\textwidth]{#2}}
\narrowlinect=\imageheight\relax
\setcounter{ct}{\numexpr((\narrowlinect)/\baselineskip+2)\relax}
\setlength{\leftskip}{\leftmargin}\mbox{}\vspace*{-\baselineskip}%
\InsertBoxL{#1}{\begin{threeparttable}%
\begin{tabular}{c@{}}\includegraphics[width=#4\textwidth]{#2}\end{tabular}%
\caption*{Pict. \thepictnumber}\end{threeparttable}}[\numexpr(\value{ct}/2+#1+1)]\par
\hspace{\itemindent}
}%
\newcommandx{\InsertPictR}[4][1=0,3=0]{\refstepcounter{pictnumber}%
\settoheight\imageheight{\includegraphics[width=#4\textwidth]{#2}}
\narrowlinect=\imageheight\relax
\setcounter{ct}{\numexpr((\narrowlinect)/\baselineskip+2)\relax}
\mbox{}\vspace*{-\baselineskip}\setlength{\leftskip}{\leftmargin}%
\InsertBoxR{#1}{\hskip-\leftmargin\begin{threeparttable}%
\begin{tabular}{c@{}}\includegraphics[width=#4\textwidth]{#2}\end{tabular}%
\caption*{Pict. \thepictnumber}\end{threeparttable}\hskip\leftmargin}[\numexpr(\value{ct}/2+#1+1)]
}%
\newcommandx{\InsertPict}[4][1=0,3=0]{%
\strictpagecheck%
\checkoddpage%
\ifoddpage
\InsertPictR[#1]{#2}[#3]{#4}
\else%
\InsertPictL[#1]{#2}[#3]{#4}
\fi%
}
\begin{document}
\noindent
\begin{minipage}[t]{0.7\textwidth}
\begin{thm}
\lipsum[1]
$$\int_\gamma f(z)\,dz = 0.$$
\end{thm}
\end{minipage}%
\hfill%
\begin{minipage}[t]{0.3\textwidth}
\InsertBoxR{0}{\includegraphics[width=\dimexpr(\textwidth-2mm)]{example-image-a}}
\end{minipage}
\newpage
\begin{thm}\InsertPict{example-image-a}{0.3}
\lipsum[1]
$$\int_\gamma f(z)\,dz = 0.$$
\end{thm}
\newpage
\begin{thm}\InsertPict{example-image-a}{0.3}
\lipsum[1]
$$\int_\gamma f(z)\,dz = 0.$$
\end{thm}
\end{document}
• wrapfig isn't suited to do the job, use minipages instead. – Johannes_B Mar 19 '16 at 11:06
• @Johannes_B please see my updated question. – Lust_For_Love Mar 19 '16 at 14:10
• I was mislead by your very first picture, wrapfig seems to be the best solution. cutwin is also available, but i don't have any experience. On the other hand, be advised, that wrapping images always need manual interaction. – Johannes_B Mar 19 '16 at 14:17
• I think that your question is written unnecessarily rude. – Dr. Manuel Kuehner Mar 19 '16 at 14:41
• @Dida writing like THIS is considered shouting in chatrooms or forums. I get you are frustrated. May I suggest to take a step back and try a different approach? – naphaneal Mar 19 '16 at 16:05
Here is a minipage solution. See Wrapping image with multiple theorem-like environments and displayed math to break a paragraph (wrap text).
\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[russian]{babel}
\usepackage{graphicx}
\usepackage{caption}
\input{insbox.tex}
\usepackage{threeparttable}
\usepackage{xargs}
\usepackage{mwe}
\usepackage{amsmath,amsthm,amssymb}
\newtheorem{thm}{Theorem}
\begin{document}
\noindent\begin{minipage}{\dimexpr 0.8\textwidth-\columnsep}% need some gap
\begin{thm}[Коши]\label{abc2}
Для всякой регулярной функции $f:G\to\mathbb{C}$, заданной в односвязной области G, справедливо равенство
$$\label{abc3} \int_\gamma f(z)\,dz = 0.$$
где интеграл берется по любому замкнутому простому кусочно-гладкому контуру $\gamma$, лежащему в области $G$.
\end{thm}
\end{minipage}\hfill\begin{minipage}{0.2\textwidth}
\includegraphics[width=\textwidth]{example-image-a}
\captionof{figure}{}
\end{minipage}
\end{document}
• Yes, thank you. I have already deleted my own answer, that doing it like you advice me... (because people voted down :( ) Please, see updated question. – Lust_For_Love Mar 19 '16 at 13:54
• Oh \nopar contruction from the reference should solve my first problem. But it is very manual work. – Lust_For_Love Mar 19 '16 at 13:58
• \hangindent and \parshape can automatically adjust the margins (left or right) but only affect one paragraph and don't work on equations (IIRC). – John Kormylo Mar 19 '16 at 15:07
|
2019-08-18 19:58:40
|
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|
https://mathshistory.st-andrews.ac.uk/Biographies/Blanch/
|
# Gertrude Blanch
### Quick Info
Born
2 February 1897
Kolno, Russian Empire (now Poland)
Died
1 January 1996
San Diego, USA
Summary
Gertrude Blanch was a Polish born American mathematician who did pioneering work in numerical analysis and computation.
### Biography
Gertrude Blanch was named Gittel Kaimowitz when she was born in Kolno, about 140 km north of Warsaw. Although we have given her place of birth as being in Poland, in fact at the time the country was partitioned and Gittel Kaimowitz was born in a part which was in the Russian Empire. Her parents were Wolfe Kaimowitz and Dora Blanc, and she was the youngest of their seven children. Her father emigrated to the United States with the intention of having his wife and the younger children follow him in due course. In 1907, Dora with Gittel and one other daughter, joined Wolfe Kaimowitz in New York. Gittel was ten years old when she arrived in New York and she first attended elementary school, followed by secondary school, in Brooklyn, New York. She graduated from Eastern District High School in 1914 but later in that year her father died so Gittel, who by this time was known by the Americanised version of Gertrude, decided that she would take a job so that she could support her mother.
Gertrude Kaimowitz, as she was then called, took a job as a clerk. She took American citizenship in 1921 and continued to work until her mother died in 1927. By this time she was thirty years old, but she had always wanted to further her education and so she took evening classes at Washington Square College, part of New York University. Gertrude decided to give up her job working for a hat dealer so that she could concentrate on her studies but her employer, not wishing to lose such a valuable employee, offered to pay her tuition fees if she continued to work for him. This was an attractive offer, so Gertrude continued to work for the hat dealer while studying mathematics. She graduated with a B.S. (major in mathematics, minor in physics) from New York University in 1932 and, in February of that year, legally changed her name from Kaimowitz to Blanch. She chose this name as an Americanised version of her mother's name Blanc.
Blanch had been awarded her B.S. with distinction and decided to continue to graduate study. She entered Cornell University in September 1932 and was awarded a Master's Degree in February 1934. Continuing to undertake research supervised by Virgil Snyder, she submitted her doctoral thesis Properties of the Veneroni transformation in S_4 and was awarded a Ph.D. by Cornell University in 1935. Her thesis on algebraic geometry considered a transformation which first appeared in a paper by Veneroni in 1901. These transformations had, prior to Blanch's thesis, been studied by a number of mathematicians including J A Todd, Virgil Snyder and H F Baker. Blanch published the main results of her thesis in 1937 in the American Journal of Mathematics in a paper with the same title as her thesis.
After the award of her doctorate, Blanch returned to New York City where she worked for a year as a tutor in Hunter College, replacing a member of the faculty who was on leave. After this she was employed as a bookkeeper with a firm in Manhattan who were manufacturing cameras for colour photography. In [4] she explained how she moved from being a bookkeeper to working in the Mathematical Tables Project:-
Since I didn't want to lose my knowledge of mathematics I decided to take [Arnold N] Lowan's course in relativity [at Brooklyn College]. Well actually, of course you know how evening sessions are. Most students are very tired when they come there and they don't have time to do their homework. I had the time to, and what is more I had the basic knowledge; so of course when I handed in a paper it was a paper that was fairly well written. Lowan used to take the same bus home that I did, and one day on the bus he told me that he was very pleased with the sort of papers I handed in, even though I didn't attend every night, and I told him that I did have a Ph.D. in mathematics at that time. So that's how he knew that I was a mathematician and he told me the next night on the bus that he had been selected to head this Mathematical Tables Project and wouldn't I join it?
Blanch worked on the Mathematical Tables Project from the beginning of 1938 until 1942. She published several papers, most jointly with Arnold N Lowan, such as: Tables of Planck's radiation and photon functions (1940), Errors in Hayashi's table of Bessel functions for complex arguments (1941) and On the inversion of the q-series associated with Jacobian elliptic functions (1942). The last two mentioned papers were published in the Bulletin of the American Mathematical Society. She was also employed as a tutor for evening courses at Brooklyn College from 1940 to 1942. In December 1941 the Japanese attacked the US navy in Pearl harbour and the United States entered World War II. The National Bureau of Standards took over most of the staff of the Mathematical Tables Project in 1942 for their work with the Applied Mathematics Panel of the National Defense Research Committee. Blanch said that after that [4]:-
We had a much smaller group, but we had equipment. We even had IBM equipment in those days. That was during the war when some of our things that we had worked on were flown to Los Alamos because they were needed. Some material we happened to have had it in our files. ... At that time we knew how to do things. We had expertise.
Up to 1948 the Mathematical Tables Project continued in New York but it was then moved to Washington. Blanch did not go to Washington, however [4]:-
... at that time I was asked to go to the West Coast to the Institute for Numerical Analysis to start the laboratory there and I was tickled pink to go. I had never been to the West Coast, so for me California was a revelation. ... Now I stayed in California up to the McCarthy era when the Institute folded.
The McCarthy era to which Blanch refers in this quote began in February 1950 when the United States Senator Joseph R McCarthy made unsubstantiated claims that Communists had infiltrated high government circles [1]:-
[Blanch] was one of the professional staff of the Institute who were investigated by a loyalty board of the Department of Commerce, which oversaw the National Bureau of Standards. Although previously Blanch had been denied security clearance, presumably because her sister was a member of the Communist Party, she was allowed to continue her job with the Institute. Nonetheless, the Institute was under attack and it closed in June 1954.
As well as her sister being a member of the Communist Party, other evidence against Blanch was the ridiculous claim that she was likely to be a Communist because she had never married or had children. Blanch got a job with the Electrodata Corporation in Pasadena but only worked for them for a year before she became a senior mathematician at the Aerospace Research Laboratories at the Wright Patterson Air Force Base in Dayton, Ohio. She already had connections to the Wright Patterson Air Force Base having worked on Mathieu functions for Henry Fettis who worked there [4]:-
... on Mathieu functions I was probably the only one who had any experience with them, and I helped Fettis out in some things that had given him a lot of trouble. He couldn't get anybody to help him with [it]. So apparently when they realized that I might be available, the one in charge of the mathematics group at Wright-Patterson Air Force Base was Dr Millsaps, a real Southern gentleman who got his degree with Von Karman in mathematics. ... Millsaps tried to get me to come to Wright Field. Every time he came to California he would invite me to have dinner with him. ... I realized that the firm I was with would not be in business very long before it would be sold to somebody, and Millsaps had asked me three times. I didn't want to leave California, but then I decided maybe I'd better, and I took the job. In many ways it was the best thing I ever did. ... I left at the right time and I was never happier anywhere - I was never as happy in any other place as I was at Wright Field. I had complete freedom to do exactly what I wanted the way I wanted to do it and, I think, my best work was done there.
Blanch's first published paper on Mathieu functions was published in 1946, before she went to California. This was the paper On the computation of Mathieu functions which was reviewed by L J Comrie who begins his review as follows:-
For the Mathieu equation $y" + (a - 2 q \cos 2x)y = 0$, it is well known that certain values of a, described as characteristic values, lead to periodic solutions. Ince, Goldstein and, more recently, McLachlan have developed methods of obtaining these characteristic values from a continued fraction. The author remarks, "there does not seem to appear in the literature any method for improving the accuracy of the characteristic values, except by cumbersome iteration." She then develops a method which corrects not only an approximate characteristic value, but also the coefficients in the series for the periodic solutions.
However, in 1945 the National Bureau of Standards had produced a volume of Tables relating to Mathieu functions which had included work by Blanch.
Among other papers that Blanch wrote before moving to Wright Patterson Air Force Base were: (with Roselyn Siegel) Table of modified Bernoulli polynomials (1950), On the numerical solution of equations involving differential operators with constant coefficients (1952), On the numerical solution of parabolic partial differential equations (1953) and (with Henry E Fettis) Subsonic oscillatory aerodynamic coefficients computed by the method of Reissner and Haskind (1953).
In [4] she describes her work at the Wright Patterson Air Force Base:-
Primarily I was working on Mathieu functions. We did Mathieu functions in a complex plane and it is published. We didn't do very much routine computing there. [Carl Gottfried] Guderley used to have some very interesting special problems in connection with some thermodynamic theory. We'd help with those. People from here, there, and other laboratories at Wright Field would come for advice, and if we had the knowledge we were very glad to share it. We would have lectures on modern mathematics and so on. We all participated in them. It was a college atmosphere. They had a graduate institute ... They teach aerodynamics primarily to those officers who needed training.
Examples of her work on Mathieu functions during her time at Wright Field is the paper The asymptotic expansions for the odd periodic Mathieu functions (1960) published in the Transactions of the American Mathematical Society and the paper Numerical aspects of Mathieu eigenvalues (1966). She also published a two-volume book with D S Clemm Tables relating to the radial Mathieu functions. The first volume subtitled Functions of the first kind appeared in 1962 and the second volume Functions of the second kind was published three years later.
In 1967 Blanch retired from her job at Wright Patterson Air Force Base and was honoured with the publication of Blanch anniversary volume (1967), which contained a series of papers by her friends. She continued to publish on Mathieu functions with D S Clemm after retiring, publishing the paper The double points of Mathieu's differential equation (1969) and the book Mathieu's equation for complex parameters. Tables of characteristic values (1969). Until 1970 she was employed by Ohio State University as an Air Force consultant. After 1970 she returned to California where she lived a long retirement, dying just a month before her ninety-ninth birthday.
Let us end this biography by quoting David Grier [3]:-
Gertrude Blanch can be viewed as either the last and most important leader of human computers or one of the first numerical analysts for electronic computers.
### References (show)
1. J Green and J LaDuke, Pioneering Women in American Mathematics : The Pre-1940 PhD's (American Mathematical Society, Providence, RI, 2009).
2. G Blanch and I Rhodes, Table-making at the National Bureau of Standards, in Studies in numerical analysis (papers in honour of Cornelius Lanczos on the occasion of his 80th birthday (Academic Press, London, 1974), 1-6.
3. D A Grier, Gertrude Blanch of the Mathematical Tables Project, IEEE Ann. Hist. Comput. 19 (4) (1997), 18-27.
4. H Tropp, Interview with Gertrude Blanch at the Aspen Hotel in Washington, D.C. on 16 May 1973 (Computer Oral History Collection, 1969-1973, 1977, Archives Center, National museum of American History).
|
2020-08-10 09:12:15
|
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|
https://stats.stackexchange.com/questions/539499/standard-deviation-of-the-model-r2-in-loocv-in-caret
|
# standard deviation of the model R2 in LOOCV in caret
I am performing a LOOCV linear model and I got the parameters R2 and RMSE, but I was wondering if there is a way to calculate the standard deviation of the model R2. I tried to do it in the same way I do it for k-fold cross-validation but it does not work.
This is my model
train.control <- trainControl(method = "LOOCV")
model_amb <- train(rate ~ volume, data = data_amb, method = "lm", trControl = train.control)
summary(model_amb)
sd(model_amb$$resample$$Rsquared)
This is what I get when I run the last line
sd(model_amb$$resample$$Rsquared)
[1] NA
• Do you mean the standard error? The terms are not synonyms.
– Dave
Aug 8 '21 at 3:35
• It is the standard deviation, I usually calculate the standard deviation around the R-squared value by examining the R-squared from each fold when I do k-fold cross validation. But I think I can not do it if I am doing LOOCV, I would like to know if I can calculate that with LOOCV and if yes, how? Aug 8 '21 at 13:27
• What happens when you try to calculate the LOOCV standard deviation the same way you calculate it for k-fold?
– Dave
Aug 8 '21 at 13:41
• I got NA, the code and output is above Aug 8 '21 at 13:44
• How are you calculating model_amb\\$resampleRsquared? Does that have NA values? All NA values?
– Dave
Aug 8 '21 at 13:46
|
2022-01-23 07:03:01
|
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|
https://eprint.iacr.org/2011/671
|
Improved Results on Impossible Differential Cryptanalysis of Reduced-Round Camellia-192/256
Ya Liu, Dawu Gu, Zhiqiang Liu, Wei Li, and Ying Man
Abstract
As an international standard adopted by ISO/IEC, the block cipher Camellia has been used in various cryptographic applications. In this paper, we reevaluate the security of Camellia against impossible differential cryptanalysis. Specifically, we propose several 7-round impossible differentials with the $FL/FL^{-1}$ layers. Based on them, we mount impossible differential attacks on 11-round Camellia-192 and 12-round Camellia-256. The data complexities of our attacks on 11-round Camellia-192 and 12-round Camellia-256 are about $2^{120}$ chosen plaintexts and $2^{119.8}$ chosen plaintexts, respectively. The corresponding time complexities are approximately $2^{167.1}$ 11-round encryptions and $2^{220.87}$ 12-round encryptions. As far as we know, our attacks are $2^{16.9}$ times and $2^{19.13}$ times faster than the previously best known ones but have slightly more data.
Note: We have revised some minor mistakes.
Available format(s)
Publication info
Published elsewhere. Unknown where it was published
Keywords
Block CipherCamelliaImpossible Differential Cryptanalysis
Contact author(s)
liuya0611 @ sjtu edu cn
History
2011-12-22: last of 2 revisions
See all versions
Short URL
https://ia.cr/2011/671
CC BY
BibTeX
@misc{cryptoeprint:2011/671,
author = {Ya Liu and Dawu Gu and Zhiqiang Liu and Wei Li and Ying Man},
title = {Improved Results on Impossible Differential Cryptanalysis of Reduced-Round Camellia-192/256},
howpublished = {Cryptology ePrint Archive, Paper 2011/671},
year = {2011},
note = {\url{https://eprint.iacr.org/2011/671}},
url = {https://eprint.iacr.org/2011/671}
}
Note: In order to protect the privacy of readers, eprint.iacr.org does not use cookies or embedded third party content.
|
2022-12-01 13:06:20
|
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|
https://commons.apache.org/proper/commons-math/userguide/genetics.html
|
## 14 Genetic Algorithms
### 14.1 Overview
The genetics package provides a framework and implementations for genetic algorithms.
### 14.2 GA Framework
GeneticAlgorithm provides an execution framework for Genetic Algorithms (GA). Populations, consisting of Chromosomes are evolved by the GeneticAlgorithm until a StoppingCondition is reached. Evolution is determined by SelectionPolicy, MutationPolicy and Fitness.
The GA itself is implemented by the evolve method of the GeneticAlgorithm class, which looks like this:
public Population evolve(Population initial, StoppingCondition condition) {
Population current = initial;
while (!condition.isSatisfied(current)) {
current = nextGeneration(current);
}
return current;
}
The nextGeneration method implements the following algorithm:
1. Get nextGeneration population to fill from current generation, using its nextGeneration method
2. Loop until new generation is filled:
• Apply configured SelectionPolicy to select a pair of parents from current
• With probability = getCrossoverRate(), apply configured CrossoverPolicy to parents
• With probability = getMutationRate(), apply configured MutationPolicy to each of the offspring
• Add offspring individually to nextGeneration, space permitting
3. Return nextGeneration
### 14.3 Implementation
Here is an example GA execution:
// initialize a new genetic algorithm
GeneticAlgorithm ga = new GeneticAlgorithm(
new OnePointCrossover<Integer>(),
1,
new RandomKeyMutation(),
0.10,
new TournamentSelection(TOURNAMENT_ARITY)
);
// initial population
Population initial = getInitialPopulation();
// stopping condition
StoppingCondition stopCond = new FixedGenerationCount(NUM_GENERATIONS);
// run the algorithm
Population finalPopulation = ga.evolve(initial, stopCond);
// best chromosome from the final population
Chromosome bestFinal = finalPopulation.getFittestChromosome();
The arguments to the GeneticAlgorithm constructor above are:
Parameter value in example meaning
crossoverPolicy OnePointCrossover A random crossover point is selected and the first part from each parent is copied to the corresponding child, and the second parts are copied crosswise.
crossoverRate 1 Always apply crossover
mutationPolicy RandomKeyMutation Changes a randomly chosen element of the array representation to a random value uniformly distributed in [0,1].
mutationRate .1 Apply mutation with probability 0.1 - that is, 10% of the time.
selectionPolicy TournamentSelection Each of the two selected chromosomes is selected based on an n-ary tournament -- this is done by drawing n random chromosomes without replacement from the population, and then selecting the fittest chromosome among them.
The algorithm starts with an initial population of Chromosomes. and executes until the specified StoppingCondition is reached. In the example above, a FixedGenerationCount stopping condition is used, which means the algorithm proceeds through a fixed number of generations.
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2014-03-10 01:36:00
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https://testbook.com/question-answer/a-carnot-engine-receiving-heat-at-400-k-has-an-eff--600631de92844a342fa68aec
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A Carnot engine receiving heat at 400 K has an efficiency of 50 %. What is the COP of a Carnot refrigerator working between the same temperature limits?
This question was previously asked in
SSC JE ME Previous Paper 8 (Held on: 27 October 2020 Evening)
View all SSC JE ME Papers >
1. 4
2. 1
3. 2
4. 3
Option 2 : 1
Free
SSC JE ME Full Test 4
5872
200 Questions 200 Marks 120 Mins
Detailed Solution
Concept:
$$η_{carnot}=\frac{T_H-T_L}{T_H}=1-\frac{T_L}{T_H}$$
$$(COP)_{carnot}=\frac{T_L}{T_H-T_L}$$
Calculation:
Given:
ηCarnot = 50 % = 0.5, TH = 400 K
$$η_{carnot}=\frac{T_H-T_L}{T_H}=1-\frac{T_L}{T_H}$$
$$\Rightarrow\frac{T_L}{T_H}=0.5=\frac{1}{2}$$
Now,
$$(COP)_{carnot}=\frac{T_L}{T_H-T_L}=\frac{1}{\frac{T_H}{T_L}-1}=\frac{1}{2-1}=1$$
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2021-12-03 17:30:42
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http://en.wikipedia.org/wiki/Wikipedia:Help_desk/Archive_35
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# November 21
## Translating articles
I would like to translate many articles in Wikipedia to the Spanish version, however I have not found a proper procedure for doing so. Cross-wiki links and such. Is there a place that outlines the general procedure for this? Thanks! --Kitsune Sniper / David Silva 00:44, 21 November 2005 (UTC)
Please see Wikipedia:Multilingual coordination. -- Rick Block (talk) 03:33, 21 November 2005 (UTC)
## Search Terms and accepted usage
1. I wrote an article about TALKING ATMs
2. Someone wanted it merged into the ATM article, where it now resides under the heading "Disability Assisted ATMs"
3. The term "Talking ATM" is not a searchable term even tho the term is in the part of the ATM article referred to above.
4. How can I set it so if someone searches for "Talking ATM" they end up in the "disability Assited ATM" section - or at least in the ATM section?
5. Also - NOBODY refers to these machines as "disability assisted" -- the term is not used and incorrect. Where would I put a suggestion to change the term back to "Talking ATM"
Thanks!
Lainey Feingold (who has been working with the blind community on TALKING ATMs for 10 years!)
Hi, Lainey. The easist thing to do would be to create a redirect. See Wikipedia:Redirects for information on how to create one. I know you can redirect to a section within an article, but I'm not sure how common it is. It may be confusing to the user. Anyway, what you do, in brief is create an article called Talking ATM and put the text:
#REDIRECT [[Automatic Teller Machine#Disability Assisted ATMs]]
into it and save the page. HorsePunchKid 2005-10-21 04:19:30Z
It sounds like you might want to be bold and change the section name to "Talking ATMs" first (before adding the redirect). Note that redirects to sections within an article do not currently work - the redirect will go to the article, but not the specific section. It's probably not a bad idea to redirect to the section anyway, anticipating some point in the future when redirects to sections will work. -- Rick Block (talk) 04:50, 21 November 2005 (UTC)
I don't think it is a good idea to redirect to a section. If the section is renamed, the redirect would die. - 131.211.210.16 08:19, 21 November 2005 (UTC)
The Wiki software doesn't support redirects to sections.
The correct term to use here is the one used in the sources on which the article was based, although the article seems to fail to identify them. --David Woolley 10:50, 21 November 2005 (UTC)
## Apparent duplicate article
In "What links here" for the article "Stroboscope", one of the linking articles is also named "Stroboscope". Is something wrong? BrownBean 04:28, 21 November 2005 (UTC)
• No, articles often (if not always) have themselves listed in that section. If you check orphan pages, you'll see the same thing happen. Check if the term isn't linked in the article instead of bolded, though. - 131.211.210.16 08:20, 21 November 2005 (UTC)
Thanks! BrownBean 01:39, 22 November 2005 (UTC)
## FALSE and False programming language
I wrote a fairly extensive article on the programming language FALSE. Then not long after, I found that there already was an article called False programming language that I had managed to miss entirely. I'm working on merging them, but I need some help as to which of the two article titles I should merge into.
In favor of FALSE:
• the manual for the language always capitalizes it, indicating that FALSE is the proper form.
In favor of False programming language
• the homepage for the language never capitalizes it, indicating that False is the proper form.
The manual is in plaintext, so perhaps it is only "FALSE" there to give emphasis to the name. On the other hand, the author doesn't seem to add any more emphasis to the name than a leading capital in the remainder of the site (where he is not restricted to all-caps to add emphasis; having html it could be bold or some such).
Given this contradiction, I'm at a bit of a loss. Also see Talk:FALSE.
Ethan (talk) 04:43, 21 November 2005 (UTC)
## Lately edited page exchanged by an older version
I renewed a page with up-dated facts and nice pics, but it is replaced by a very old short version every second day. Why? Thanks in advance Sky Tower
There could be a number of reasons, some good, some bad. But before you can get a clear answer, you'll need to tell us which article you changed. jnothman talk 06:24, 21 November 2005 (UTC)
If you're referring to your edits on the Carlsberg Sky Tower article, it was stated in the edit summary that the user was making their edits so that the article would be more in line with Wikipedia standards. For instance, they removed some of the sensationalistic wording that was present. Also, when making a section title with double = signs, it's not necessary to put the words in between the ='s in bold. I see that you're a new editor, at least under your current user name, so I would suggest taking a look at the pages under Help:Contents for more information on article style and various other helpful topics. Dismas|(talk) 06:41, 21 November 2005 (UTC)
You can get more details about edits by clicking the History button at the top of any page. In this case, your edits were also removed because, the history says, they were copied from http://www.melchers.com.sg/st/index.htm. Wikipedia cannot allow this, as it would be a copyright violation (unless there is a special form of permission from the original author). Almost all text, like almost all photos, on the internet, are copyright so you cannot just copy them. Notinasnaid 08:33, 21 November 2005 (UTC)
## Moel Tryfan
I was re-directed to Tryfan from Moel Tryfan while cross checking links from North Wales Narrow Gauge Railway. I know enough to know these are different mountains, 9½ miles apart.
Can we have the re-direct taken off please? AHEMSLTD 14:22, 19 November 2005 (UTC)
You can edit the redirect yourself. You either need to make it into an article for the mountain or into a Wikipedia:disambiguation page for that and the railway engine that comes out top on Google. You could also make it into a redirect for the railway, assuming that there is mention of the engine, there, but it will have to change if someone adds the mountain.
You shouldn't, however, create an article on the basis of "I know enough to know", but only on the basis of verifiable sources.
More information, including how to get the redirect completely removed, can be found at Wikipedia:Redirects for deletion. --David Woolley 13:55, 21 November 2005 (UTC)
## Problem with search
I don't know if this is a bug or a problem with my set-up. When I search for "Kitchener Ontario", in the user namespace, I get results 1-20 of 225. But if I click on "next" or "2" to get the second page, it says there were no matches to the query. What's going on? -- 192.206.151.130 16:11, 21 November 2005 (UTC)
It seems to be working fine now. - Akamad 19:28, 21 November 2005 (UTC)
## Blocked for Vandalism
A note has come up whilst using Wikipedia saying that I have been blocked from amending articles because of repreated vandalism of articles. I was not aware I have done this, and if I have it is certainly inadvertent. I have used Wikipedia to get much information, and I have been amending just the birth and death records of politicians which I have the information and Wikipedia does not and have added this information to the articles. But I appear to have upset someone (who hasnt contacted me directly). HELP! I am happy continuing using Wikepedia but just wanted to put something back in. :) RobStreatham —Preceding unsigned comment added by RobStreatham (talkcontribs) 16:23, 21 November 2005 (UTC)
Is it possible you got this message while you were not logged in as RobStreatham and just your IP address identified you? I have suggested that no one without a username be allowed to edit since this would solve a lot of these cases of mistaken identity, but that seems to be counter to some basic wiki concepts.... At any rate, you don't seem to be blocked now....
Charlie Richmond 16:50, 21 November 2005 (UTC)
It's also possible that he was editing from a shared IP address—through an ISP proxy server or IP address pool. Even if RobStreatham was logged in, the autoblocker will still nail you if the underlying IP address has been blocked—this helps to prevent vandals from creating new accounts while blocked, but can sometimes result in collateral blocks to good editors. TenOfAllTrades(talk) 17:31, 21 November 2005 (UTC)
It could possibly be a Trojan Horse which can mimic an open proxy or shared ip which has been used for vandalism. Perhaps it would good to run a security check on your system.--Dakota t e 17:45, 28 November 2005 (UTC)
## Can a user be blocked from certain pages.
Just out of curiosity. When someone is banned from editing a certain group of articles or topic, how does the community make sure he hasn't broken his punishment? Does Wikipedia have a feature that allows to block certain pages from a user, or the decision is followed by watching the user's activities? CG 17:15, 21 November 2005 (UTC)
Per-page blocking has been discussed in the past, and met with quite good support, but isn't yet implemented. Generally, if a page is contentious enough, someone will be watching it and aware of banned editors... Shimgray | talk | 17:25, 21 November 2005 (UTC)
• If someone is banned from editing certain articles, someone will be checking their list of contributions and the articles they're banned from. - Mgm|(talk) 22:10, 21 November 2005 (UTC)
## Index case-sensitive
This behavior causes articles to be effectively lost or duplicated.
Is there any way around this problem?
Thanks!
Please see Wikipedia:Naming conventions (capitalization)#Case sensitivity and searching. -- Rick Block (talk) 20:21, 21 November 2005 (UTC)
# November 22
## Can't get this right
would someone please have a look at the Paddy Casey page? In the singles section of the discography the first single is out of place in the table. i can't get it to go down where it should be, and i feel like i've tried everything... any chance anyone else would have a look and see if they can set it right?
cheers guys!
NaLaochra 02:40, 23 November 2005 (UTC)
Fixed. --LesleyW 04:02, 28 November 2005 (UTC)
## need a translation
what is "nik" and "donatello's"
## User is promoting a book
Hi. How do I report a user who keeps on adding material about a person and this person's book on various pages? He never adds HTML links, so I can't call it link-spamming. He has never contributed anything else. I suspect this user and this book author is the same person. Also, what warning can I give? -- Perfecto 01:37, 22 November 2005 (UTC)
If you're unsure what to do, try leaving a note at Wikipedia:Administrators' noticeboard/Incidents, with some links to articles and the user in question, and someone there will have a look at it. It does sound fishy, from your brief description; is it a recent book, and are they particularly relevant articles? Shimgray | talk | 01:43, 22 November 2005 (UTC)
## Straits Of Magellan/Drake Passage
The pictures in these articles are failing to load.
• As the note near the top of your screen should say, server installation is preventing the display of images. Deltabeignet 05:11, 22 November 2005 (UTC)
## Need help reading German to verify article
There is no German/Deutsch/Germany/Deutschland regional notice board, so I don't know where to ask for help. I need help from someone familiar with Germany or German to verify the article THTR-300. Is this a notable, real-life power plant? -- Perfecto 04:17, 22 November 2005 (UTC)
It was a real-life power plant, and imho notable enough - notice the building costs and the size of the cooling tower, also because of its political significance in the nuclear power controversy in Germany in the 70s and 80s. The article is a clumsy translation of de:THTR-300, but you can google english-language sources - for example, here the European Commission stated THTR 300 is the largest reactor of its type in the world. regards, High on a tree 02:20, 23 November 2005 (UTC)
## Quick revert?
I've noticed the typical text to revert something is: Reverted edits by 12.217.63.92 to last version by K1Bond007, but with the 12.217.63.92 changed to that person's contributions. How do I wikify that? Also, is there an easy way to write that without constantly typing that in? Thanks. --JHMM13 05:49, 22 November 2005 (UTC)
Admins can do it by doing something they call a rollback. The rest of us have to type it in if we want it to read that way. Dismas|(talk) 05:51, 22 November 2005 (UTC)
Ah, man. Well in that case, is there any sort gold standard to which everyone must adhere, or can I just say "rv" or "rv from blahblah back to shimsham?" --JHMM13 05:54, 22 November 2005 (UTC)
• Yes you can, provided you are clear about what "blahblah and shimsham" mean. - Mgm|(talk) 05:59, 22 November 2005 (UTC)
Oh, well obviously! I simply meant that those would be the two users. Thanks, guys. --JHMM13 06:01, 22 November 2005 (UTC)
The recommended edit summary is "rv edits by 219.148.86.36 to last version by David Shear". See WP:RV. It is particularly important in the case of multiple edits by David Shear to state explicitly the version to which you are reverting. --Walter Siegmund (talk) 06:18, 22 November 2005 (UTC)
I'll chime in to note that if it's simple, obvious, clear vandalism then you can use a very abbreviated edit summary. rvv for 'revert vandalism' is sufficient. TenOfAllTrades(talk) 08:38, 22 November 2005 (UTC)
## Hrm, is my cache acting up, or is my subcat not working?
Just a really quick question, but I tried to create the subcat of Category:Religious NPOV disputes to help subcat the extrememly large Category:NPOV disputes, but when I look at the latter, it's not showing the subcat the first as a subcat >:\ Sherurcij 09:06, 22 November 2005 (UTC)
You need to add a subcategory to the category like you do with articles for it to be automated. I'll do it for ya. - 131.211.210.16 09:17, 22 November 2005 (UTC)
Hmm, you seem to have done it correctly, but the category isn't showing up as a subcategory in Category:NPOV disputes. Odd... - 131.211.210.16 09:21, 22 November 2005 (UTC)
Yeah...anybody have any ideas what's going on? Sherurcij 09:43, 22 November 2005 (UTC)
The category is showing up. The problem here is (what may be a MediaWiki bug) that the category only shows up under R, and not up the top. That is, you will find the category listed here but not on the main category page. jnothman talk 12:41, 22 November 2005 (UTC)
• That's a bug all right. Subcategories should be showing up under a subcategory header, not along with the articles. Can someone with more time on their hands please report it? - Mgm|(talk) 17:33, 22 November 2005 (UTC)
It was reported by David Gerard in December 2004, but is still unassigned. jnothman talk 04:54, 23 November 2005 (UTC)
## how do i cite
—Preceding unsigned comment added by 71.120.176.26 (talkcontribs)
Do you mean how do you cite your sources when writing an article, or do you mean, how to cite Wikipedia elsewhere? --David Woolley 13:43, 22 November 2005 (UTC)
I could imagine this to be a troll, given the number of times one is told not to ask that question on this page. Banana04131 04:28, 23 November 2005 (UTC)
## Changing link colour in one instance
I'm sure there's a clever CSS way to do it, but I'm not sure how. How can I get a wikilink to appear in white text when it's against the black background of a table cell? If left its normal blue colour, the link is virtually invisible. --Gareth Hughes 13:55, 22 November 2005 (UTC)
Well, if I wanted to type the link Wikipedia in white, I would type the following:
<font color="#FFFFFF">[[Wikipedia]]</font>
This looks like Wikipedia. I'm not sure if this is what you want, though. Izehar 17:47, 22 November 2005 (UTC)
The other question is—does the table background need to be black? TenOfAllTrades(talk) 18:19, 22 November 2005 (UTC)
No, the script I typed above will make the letters white, regardless of the background colour. Izehar 18:57, 22 November 2005 (UTC)
That is just obvious when somebody shows you the answer. Thank you all. The text is in {{language/quilt}}: different language classes are colour coded. Unfortunately, one of the chosen colours is black, and in a few cases, I want link text on the black background. I hope that's clear. Thanks. --Gareth Hughes 23:27, 22 November 2005 (UTC)
I was wondering if there was something wrong with my browser, as it appeared to format the link as only the blue underlined bar, then I remembered that white text on a very pale blue background doesn't stand out too well. Rather than strain my eyes out, I used xmag to verify that there were white pixels there. — JIP | Talk 15:25, 2 December 2005 (UTC)
## use keywords
—Preceding unsigned comment added by 216.11.209.13 (talkcontribs)
No content, but this IP address has a history of subtle (date changes), and unsubtle (sexually explicit passages in inappropriate articles) vandalism. --David Woolley 17:09, 22 November 2005 (UTC)
Unlike other items in an article (wikify, copyedit, etc), I never see a {contents} tag, so I wonder what makes one? How do you add it? Right now, I can only do this by copying a segment out of an existing article with a Table of Contents. Also, How do you set where the Contents appears? I see some pages with it at the top, but most have it after the intro paragraph. What is the "proper" location? Rlevse 17:42, 22 November 2005 (UTC)
• The proper location is after the intro paragraph, but sometimes images and infoboxes don't allow this placement, in which case it's moved. - Mgm|(talk) 05:57, 23 November 2005 (UTC)
## Pictures
Why are some pictures not showing up? 130.111.98.131 18:58, 22 November 2005 (UTC)
There should be a note at the top of this very page about the new image server that's being installed. That's probably why; hopefully they'll start showing up again soon! HorsePunchKid 2005-10-22 19:22:18Z
## Taxobox
What is a taxobox? Someone said I needed one. and how do I make one? Thanks --LPW 20:26, 22 November 2005 (UTC)
A taxobox, like an infobox, is a table near the top of a page that summarizes the information given for an organism. See Wikipedia:Infobox and WP:TOL for more. Deltabeignet 22:47, 22 November 2005 (UTC)
(after collision)
It's the thing at the top right hand side of the Oleander article. However, I also said that you needed to merge your article into Oleander, or take both articles and produce one about the plant, which needs the taxobox, and one about the associated toxicology that doesn't. At the moment, I think you should merge; you can split when the toxicology part gets large enough. --David Woolley 23:03, 22 November 2005 (UTC)
# November 23
## "Save Page" editor button only previews page.
I recently set up a personal wiki to manage notes and whatnot. The install went through without much trouble. But whenever I attempt to save a page using the "Save Page" button I get sent to a preview page with the generic
Remember that this is only a preview, and has not yet been saved!
preview page line. i have tried editing various types of pages (main page, talk, discussion), as well as creating new pages. None of them allow me to save pages. I've tried editing from a sysop account and regular account, no dice. saving my preferences is also out of the question.
however, i am able to edit pages anonymously, which makes it all the more confusing. it seems like something gets set read-only once i log in, but i'm not familiar enough with mediawiki to know what.
TIA, tom link to my wiki
I signed into your wiki and couldn't reproduce your problem. sorry. jnothman talk 04:00, 23 November 2005 (UTC)
Something similar sometimes happens on Wikipedia; I'm not sure whether it's related to server load, bad luck, or the phase of the Moon, however. The question has definitely come up before. TenOfAllTrades(talk) 04:05, 23 November 2005 (UTC)
after reading your posts i tried connecting to the wiki via a proxy and i had no problems. i turned off the proxy and encountered the same problems. i am on the same subnet as the server, i wonder if that could be causing the problem. -tom
## Edit conflicts in reverting
Or better yet, the lack thereof. Many times I've reverted vandalism, saved my edits, and found via the history that someone else had already reverted it; however, I can't remember ever getting an edit conflict for any of these. I'm guessing this is either a technical issue or something to do with merging identical edits. Deltabeignet 05:59, 23 November 2005 (UTC)
That's how it should be. When you and someone else are reverting vandalism, you are, in fact, making the exact same change - rv'ing to the last good version. Since the changes are identical, there's no reason for an edit conflict to come up. Solver 15:27, 23 November 2005 (UTC)
Yup. Try it out sometime: Just hit the edit button on an article and hit "Save page" without making any changes. When you click on "history", you will not see a new entry, since no change was made. I agree that it's a little disorienting when you hit "save" and nothing appears to happen, but it's a good thing once you get used to it! HorsePunchKid 2005-10-23 20:15:37Z
## Contacting an Admin on Danish Wikipedia
I am working on the Wikipedia Mailing List. A user in Brazil wants to leave information for an admin on the Danish Wikipedia. How can I get in touch with her and let her know.
Capitalistroadster 06:04, 23 November 2005 (UTC)
Well, if the information is for any admin on da:, not for a particular one, she might want to contact one of the admins listed on Special:Listusers/sysop for that Wikipedia. Titoxd(?!?) 17:09, 23 November 2005 (UTC)
## Copying multiple pages from one wiki to another
I want to transfer all the Taxobox templates from en wiki to telugu wiki. Is there a way I can do this quick ? --Vyzasatya 07:10, 23 November 2005 (UTC)
## Article on Methane is being messed up
Article on Methane is being messed up with random words
Yes, it was vandalized. Thanks for trying to clean it up, I've now gone ahead and reverted to the last uncompromised version. You can help us when you see that happening by reverting the vandalism yourself. Titoxd(?!?) 18:23, 23 November 2005 (UTC)
## Last names
Does a last name have it's own symbol? I am looking for a symbol for the last name HURTADO.
Thank you
I've never heard of a last name haveing a symbol. A royal or other wise important family may have a symbol but not usually ordinary names. This is a place to ask for help on useing wikipedia. You might want to see the refrence desk although I doubt they could help you. Banana04131 20:49, 23 November 2005 (UTC)
How do I create a link to: Wikipedia Article Web URL
Thanks,
Yesselman 17:33, 23 November 2005 (UTC)
Inside Wikipedia, you can try [[Wikipedia]]. As for the URL, it is http://en.wikipedia.org/wiki/Wikipedia Titoxd(?!?) 18:19, 23 November 2005 (UTC)
## dora the explora
I am interested in purchasing Dora the Explora dubbed in German and have tried multiple web sites with no sucess. I have also called Niceledoen to no avail. Are you able to help tell me where I can order via e-mail Dora the explora dubbed in german.
Thank you.
This page is to ask Wikipedia-related questions only. I'm not sure how we can help. Titoxd(?!?) 18:17, 23 November 2005 (UTC)
• I'd recommend trying Amazon.de. My german isn't good enough to see if they have them translated there. Wikibofh 18:18, 23 November 2005 (UTC)
BTW, it might help if you had the show's name & the network's name correct; the show is "Dora the Explorer," and the network is Nickelodeon.
## Has anyone ever gotten solicited over wikipedia?
Has anyone ever gotten solicited by chatting over wikipedia? --anon
Not to my knowledge. Izehar 18:51, 23 November 2005 (UTC)
Frequently, haven't you? You must be contributing to the wrong kind of articles. Try solicitor. --Gareth Hughes 19:06, 23 November 2005 (UTC)
Does this mean that Wikipedia isn't as safe as it seems? Is it like a chat room you're saying? --anon
Read Wikipedia:What Wikipedia is not; all your questions will be answered there. Izehar 19:48, 23 November 2005 (UTC)
I read it, but it didn't say, "Wikipedia is not a chat room." It just said not to talk about other things on article's talk pages and do it on a user's talk page instead. --anon
Anon, I think Gareth was making gentle fun of you, as you didn't immediately specify which of the many meanings of "solicited" you were asking about. If you means "solicited by sex-weirdos for illegal meatspace fun" then no, I don't think that's happened, nor do I think it's likely. Everything here is logged and correlated back to its author, and discussions that diverge from wikipedia articles (over to "what kind of porn movies do you like") get stepped on pretty hard. -- Finlay McWalter | Talk 20:58, 23 November 2005 (UTC)
A couple of years ago we had a user claiming to be a women who wanted to cyber. Last heard of over at wikinfo other than that no. Everything is just too public here.Geni 14:28, 25 November 2005 (UTC)
Many members of wikipedia are teenagers and this site is friendly to them. Banana04131 21:05, 23 November 2005 (UTC)
Okay...Guess I overeacted a bit! Sorry! --anon
## How do you clean up an article?
How do you clean up an article? I have attempted to clean the E-102 Gamma article many times, but the tag is still there! Could I please have some advice? --anon
After cleaning up an article (see the Manual of Style for guidelines) you can actually remove the {{cleanup}} tag yourself to remove the notice. .:.Jareth.:. babelfish 18:54, 23 November 2005 (UTC)
But how do I know that it's actually not clean? --anon
Read Wikipedia:Cleanup and Wikipedia:Cleanup process, it may help you. You can also ask whoever added the tag to check the article after you "cleaned" it and ask him/her if it's OK for you to remove the tag. Izehar 19:52, 23 November 2005 (UTC)
Okay, I read it, and I think the article's clean! And I already wrote to the person who put the tag on, but she/he isn't answering. --anon
If the article's clean, then remove the tag - if whoever added it objects, ask him why. Izehar 20:26, 23 November 2005 (UTC)
Okay, thank you! --anon
How do you make an external link spread out? For example, I want it to look like www.wikiepdia.com, but instead, I get [1] instead. Why? --anon
In order to get www.example.org, you must type:
[http://www.example.org/ www.example.org]
Izehar 19:00, 23 November 2005 (UTC)
To provide a proper URL, you can simply miss out the square brackets, e.g. http://en.wikipedia.org/. However, in almost all cases, you ought to be providing a full citation, so that people can find the page again, even if its URL changes. There is a template, {{Web reference}}, that you can use to include almost everything you might want to include for a web citation. --David Woolley 19:17, 23 November 2005 (UTC)
Now I'm confused... Izehar 19:25, 23 November 2005 (UTC)
I'm a little confused, but I'll go test it out. www.wikipedia.com. It works! Thanks! But I still don't get the URL and web reference thing. --anon
Looks like you have what you want. If you want to see how the template works, examples are provided on its talk page. --GraemeL (talk) 19:49, 23 November 2005 (UTC)
Is it okay if I just don't use those templates? --anon
I'm sure it is - I never use them. Izehar 20:23, 23 November 2005 (UTC)
Okay, thanks! --anon
But if you're trying to reference Wikipedia, be sure to link to it at its proper address, wikipedia.org... the .com address just redirects to it. (I make it a point to fight against dot-com-itis, the disease that causes people to refuse to realize the existence of domain names that don't end in .com.) *Dan T.* 16:17, 25 November 2005 (UTC)
Okay, thanks, again! --anon
## Finding an Article with Google
In October I wrote an article on the "Battle of Salineville", a Civil War battle fought in Ohio. It was my first original article. Google does not locate that article. Also if I type only "Salineville" into the Wikipedia search box, Wikipedia does not locate my article.
I also extensively editted an existing article on capture-recapture called "mark and recapture". Google does locate that article, and Wikipedia locates it too even if I don't type in the exact name.
Is there some way I can make my "Battle of Salineville" article easier to find for people searching the internet for that information. Note that I wrote that article before I registered here. I tried linking my Civil War article to several other Civil War pages, but that hasn't made mine easier to find.
Thanks for any thoughts. -- Mark W. Miller 21:03, 23 November 2005 (UTC)
It depends. It was created on October 15 meaning that most crawlers (such as Google) will get round to crawling to it. This could take months. The best way to get search engines to recognise it is to link to the article from other articles here on Wikipedia. Obviously don't start linking on every page but there are probably some articles that can link to it. --Thorpe 21:08, 23 November 2005 (UTC)
I just searched for "site:en.wikipedia.org Salineville" on google, and Battle of Salineville was the 22nd match. Wikipedia's search index is irregularly upated. I see Salineville now redirects to Salineville, Ohio. You could add a history section to this article and link to the article about the battle. It seems to already be in Battles of the American Civil War and a number of appropriate categories. -- Rick Block (talk) 22:03, 23 November 2005 (UTC)
## #REDIRECT
Whenever I try to redirect it comes out as
1. REDIRECT.
I don't understand why. I've tried How to edit a page and Redirecting. --AidPc 21:38, 23 November 2005 (UTC)
To redirect a page to, for example Wikipedia, you must type:
#REDIRECT [[Wikipedia]]
Izehar 21:40, 23 November 2005 (UTC)
The confusion might be the preview appearance (which interprets the "#" as a numbered list indicator). When you actually save the article, it will transform itself (as if by magic) into the redirect you're seeking. -- Rick Block (talk) 21:52, 23 November 2005 (UTC)
• If you get that, you typed a space between # and REDIRECT. Remove it and it should work fine. - Mgm|(talk) 05:56, 24 November 2005 (UTC)
• Thanks. --AidPc 17:24, 24 November 2005 (UTC)
How do I create a link to a Web URL for the word Religion"
Example: Definition of Religion http://www.yesselman.com/SpinIdea.htm#Religion
Thanks,
Yesselman 17:33, 23 November 2005 (UTC)
PS: I think I am a member; am I not? If not a member, how do I become one?
To link to that website under the label religion, type the following:
[http://www.yesselman.com/SpinIdea.htm#Religion Religion]
That will produce Religion. Yes, you are a memeber - please sign you name using four tildes ~~~~ Izehar 22:01, 23 November 2005 (UTC)
## DYK
Where is the DYK page? Why is there no wikipedia entry for DYK ?
I don't understand. Izehar 22:37, 23 November 2005 (UTC)
Uhm, there is a DYK page -- have no idea if it contains whatever you might have been referring to though. .:.Jareth.:. babelfish 22:42, 23 November 2005 (UTC)
Do you mean the feature section on the main page "Did you know. . ."?Banana04131 00:16, 24 November 2005 (UTC)
# November 24
## Random Logouts?
Why am I getting logged out every few hours or days, instead of every few weeks or months as it used to be? Kaz 01:04, 24 November 2005 (UTC)
C'mon, guys, someone speak up! I've tried both IE and Netscape, and both are logging me out pretty much every time I close the browser, despite my cache and cookie settings being very liberal. What gives?Kaz 03:40, 24 November 2005 (UTC)
This won't exactly be the most helpful piece of advice I've given here, but you are about the tenth person I've seen here on the Help Desk who's been having problems in the last few months. Perhaps a quick search through the archives will turn up something useful; I don't recall any specific solutions. The standard advice is to check your browser's cookie settings and make sure that they're being allowed properly. Worst case, give Firefox a try; it seems to solve so many problems! HorsePunchKid 2005-10-24 04:10:31Z
Whenever this question pops up there is a user who thinks purging your browser's cache does the trick. Give that a go.--Commander Keane 12:03, 24 November 2005 (UTC)
OK, I already checked the cookie settings, they're as liberal as possible, but I'll try manually clearing the cache.
Firefox is actually a part of the problem, in this case, not the solution. Aside from IE simply working better, whether we like MS or not, Firefox manifested this problem first, though now IE and Netscape 8 (a good compromise for people who want to be able to view websites correctly, yet hate Microsoft) are also doing it. Kaz 16:52, 24 November 2005 (UTC)
Have you remembered to check remember across sessions at your preferences;. And I agree IE works better for for this but it isn't my favorite either.--Dakota t e 18:00, 28 November 2005 (UTC)
## Improper redirect
Black Mamba is a redirect that refers to Mamba, however the Mamba article is about Black Mambas specifically. I'm not sure how to rectify this or how to bring it to the attention of someone who can. Thanks. --Bad carpet 06:33, 24 November 2005 (UTC)
You could leave a message at Talk:Mamba, and see what other editors think, or you could post a request to move it at WP:RM (make sure to read the instructions). --Gareth Hughes 15:42, 24 November 2005 (UTC)
## Rena Mero (also known as the professional wrestler Sable)
In between the Title lineage and External links sections lie ALL the links. I don't know what is wrong with the article, but could someone help? x42bn6 Talk 08:36, 24 November 2005 (UTC)
It is the pictures that are doing this. I've seen it on many articles over the time I've been here, but equally I've seen many more articles where this does not happen. I've not heard any explaantion for what is causing it though, perhaps you should raise it at Bugzilla:? Thryduulf 09:32, 24 November 2005 (UTC)
I've sorted out the real problem, which was simply too many large photos! I've moved the Playboy ones into a gallery element within the Playboy section. wangi 11:05, 24 November 2005 (UTC)
Ah, thanks a lot. Another solution I just thought of, given the fact I now know the problem, would be to alternate the images from left to right. Not only does it look better than having the images on one side, but it also fixes the problem. x42bn6 Talk 09:39, 29 November 2005 (UTC)
## limp bizkit
i updated some text about limp bizkit and it was deleted almost immediately. Here's the message I received:
Hello, and welcome to Wikipedia! We welcome and appreciate your contributions, such as Talk:Limp Bizkit, but we regretfully cannot accept copyrighted text or images borrowed from either web sites or printed material. For more information about Wikipedia's policies and guidelines, take a look at our Five Pillars. Happy editing! --Nlu 08:49, 24 November 2005 (UTC)
>>>>>>>>>>>>>>>>
Can someone tell me whas' up with that?
thx
I assume you a referring to this edit, which is on the Limp Bizkit talk page. I can't find any websites that match the text you placed in, so to be honest, I don't know why it was deleted. Perhaps you should ask on Nlu's talk page. In regards to the actual contents of your post, feel free to add info such as that to the actual article instead of the talk page. - Akamad 11:00, 24 November 2005 (UTC)
Hello,
I created my very first account on wikipedia this morning and mistakenly used my email address as my username. When I then added a new entry, I noticed that my email address was visible. I then added a nickname, which changed the visible text, but when clicking on the nickname, my email address is again visible. I would like to change my username so it is no longer my email address and stop the display of my email address on wikipedia. Help!
JonathanKing 15:46, 24 November 2005 (UTC)
Your username is currently "<removed email>". Since you have only made one edit (this one), I'd recommend you just start again - sign off, then sign in using "JonathanKing" or "Commander King" or whatever. You could get your current username changed over at Wikipedia:Changing username, but it's much easier for everyone to just to start again. Good luck! --Commander Keane 16:26, 24 November 2005 (UTC)
The reason that we remove email addresses from comments is that a lot of naive users don't realise that including one may start them receiving spam. At least one of the reasons this user doesn't want their email is almost certainly that and they are sufficiently aware of the risks to realise what they have done. Although the address may be left on the history and list of users, it is less likely to get trawled by spammers than exposing it in the current version of this page - if it can be removed from the history, as well, I think that would be advisable. --David Woolley 18:00, 24 November 2005 (UTC)
Bureaucrats are now able to rename users again. See Changing username for more information on how to do it. Titoxd(?!?) 00:18, 25 November 2005 (UTC)
## Formatting of image in table
Could someone tell me how to get an image to sit squarely in the middle of the cell of a table on Wikipedia? I've got it horizontally centred, but it keeps floating to the top of the cell. --Gareth Hughes 16:05, 24 November 2005 (UTC)
Adding style="vertical-align: middle;" should do it. Are you perhaps specifically talking about the map in Tuareg languages? -- Rick Block (talk) 03:28, 25 November 2005 (UTC)
Thanks Rick! It's not just in that article: there are a few articles which use this new feature to allow a map or other image to be displayed in the bottom of the infobox. The bit of wikitext that is included when this option is switched on is at {{language/map}}. This includes the 'vertical-align' property. I've tried using <div> tags around the image in the article space, but that makes it disappear completely. I'm a bit stuck with this one. --Gareth Hughes 13:59, 25 November 2005 (UTC)
## Restarting a hung Article for deletion process
There is an article that I've become aware which had a hung ("no consensus") Afd, but new seems to have been abandoned by its creator without having fixed its problems. I would like to restart Afd on it, but there is an archived debate sub-page, marked "please do not change". I can find procedures for appealing completed deletions, but I can't find a procedure for retrying after a mistrial (or, for that matter, deleting a page that has had a definite keep in the past). What's the correct procedure? --David Woolley 23:28, 24 November 2005 (UTC)
You redo the nomination process, but add a "2" to the name of the AFD page ("Wikipedia:Articles for deletion/Foo2" instead of "Wikipedia:Articles for deletion/Foo"). Make sure to mention,, and link to, the old vote in your nomination for the new one, and in addition to saying why you think the article should be deleted, say why the circumstances that pertained in the former vote have changed. Without this latter part you risk people getting upset that you're renominating the same article repeatedly hoping to get a different conclusion. In any event, I wouldn't advise renominating something for at least a couple of months after its first vote. -- Finlay McWalter | Talk 23:43, 24 November 2005 (UTC)
I should note that "someone said they'd fix it, but didn't" probably isn't likely to swing things, as presumably someone else can later. If only the original author can, then the article is probably OR, however. -- Finlay McWalter | Talk 23:48, 24 November 2005 (UTC)
This almost certainly is a case of OR. Note though that no-one promised to fix the problem in question, which was that it was not V. There are other problems that are potentially fixable by third parties. The original nomination was effectively for NN, but that statelmated (it was keep by default rather than a postive decision to keep). It certainly was NN in a Western context (and by Google), but there weren't enough people with relevant regional knowledge to defnitely say it was NN in a regional context. I'll give it a little longer. --David Woolley 20:10, 27 November 2005 (UTC)
• Wasn't there instructions on how to renominate something on AFD? Where is that now?- Mgm|(talk) 05:58, 25 November 2005 (UTC)
# November 25
## Zimbabwe map showing contours and coordinates
I wish to make a map with the following: contour lines and coordinates. The map is intended toi be used to develop a disaster reduction paln for a communal area in Zimbabwe.
I don't know if we can help you here. You should post your request on Wikipedia:Requested pictures; they may be able to fix you up with something. Izehar 11:41, 25 November 2005 (UTC)
It is not clear what question you are asking, although it is likely that the question really belongs on the reference desk, because it isn't about how to use Wikipedia.
If you want a ready prepared map, the problem you may find is that this level of detail is only available in maps with copyrights that wouldn't allow their use on Wikipedia (e.g. UK Ordnance Survey maps). This will vary from country to country, but I suspect that the United States is the only real exception.
If you want to create one yourself, have a look at the Surveying article.
--David Woolley 12:13, 25 November 2005 (UTC)
## Redirect: how to switch SRC and DST?
Roman (disambiguation)Roman which claims to be a disambiguation page (although it has too much stuff on it IMHO), and I think it should be the other way around, i.e. the disambiguation content should be on Roman (disambiguation) and Roman should redirect. Can a mere mortal switch them over? If not, how do I queue it up for an an admin to look at? Or am I wrong in thinking they should be switched? --LesleyW 11:40, 25 November 2005 (UTC)
Before making a change like that, it's customary to discuss it first on the talk page, as some people may have serious objections. Page moves are a big deal, and you need at least 60% support before moving them. In my opinion, they shouldn't be switched - as Roman is not being used for anything else, it's easier to enter into the address bar. If you are set on making the change, follow the guidelines on WP:RM. Izehar 11:46, 25 November 2005 (UTC)
In my view it is correct as it is. Your proposal doesn't change the essential disambiguation nature of the page and if the primary title is free, it is generally better to use that rather than title (disambiguation). Have a look at the edit history on the Roman (disambiguation) page. There are currently no links to it other than this page, but moving it (which I believe is possible for an ordinary user) would result in double redirects (e.g. Romans which would need to be repaired). I think it would be more useful to diambiguate the incoming links to Roman, which are many. --David Woolley 12:03, 25 November 2005 (UTC)
Thanks for the input. I'll work through some of those links, then. --LesleyW 21:28, 25 November 2005 (UTC)
## Use of Images in Articles
How do I insert an image into my article and upload it? I'm having trouble finding thisRlevse 15:00, 25 November 2005 (UTC)
Not sure where you looked, but from Help (linked on every page) under "Modifying a Wikipedia page", the 6th bullet is "How to use images", which links to Wikipedia:Picture tutorial. -- Rick Block (talk) 16:35, 25 November 2005 (UTC)
To upload an image, you use the upload page. Inserting an imige is done like [[File:image.jpg]] this. There are lots of different options for formatting the images on a page and you can find more details at Help:Editing#Images and Help:Images and other uploaded files. --GraemeL (talk) 16:38, 25 November 2005 (UTC)
Thanks! I'm using the Wiki browser-based Upload File method.Rlevse 21:11, 25 November 2005 (UTC)
## Targets in Wikipedia Articles
Dear Help Desk,
Is it possible to create targets in Wikipedia Articles so that one can link to the target within the Article?
If possible; kindly tell me how.
Many thanks,
Yesselman 15:28, 25 November 2005 (UTC)
Every section header within an article becomes a target, and you can add "id=..." to many HTML elements as well, please see Wikipedia:How to edit a page#Links and URLs (which is itself an example of a target). -- Rick Block (talk) 16:28, 25 November 2005 (UTC)
## Featured Article
Can Wikipedia feature the 2005 Southeast Asian Games, a sporting event in Asia, in the main page for the next three days? The "soft-opening" happened November 25 and the games will formally open on November 27. Homboy 17:21, 25 November 2005 (UTC)
not really. It isn't a featured article (which only get one day in the sun) and I don't think it has a high enough profile for the in the news section.SorryGeni 17:26, 25 November 2005 (UTC)
• Why isn't it high-profile enough? Based on the pictures, it's pretty big in Asia. We're supposed to be an international project. I do agree, though, that the article should be updated. - Mgm|(talk) 21:09, 25 November 2005 (UTC)
## Adding Photographs When You Are The Photographer
If I wanted to add a picture to a page, and I'm the owner and photographer of the picture, which license choice do I choose? It's a public building (a bridge) and it was taken from public land. Also, since I'm the owner/photographer, is there anything else I need to do to make sure this is appropriately identified? Thanks! --EaglesFanInTampa 18:25, 25 November 2005 (UTC)
There are a number of copyright tags that you could use. The simplest is perhaps {{GFDL-self}} which indicates that you are the creator of the image and that you release the image under the GFDL: the same license as the rest of Wikipedia. Alternately, you can release the picture to the public domain using {{PD-self}}. As always, it's a good idea to put as much information about the image as possible on its description page (when and where the photograph was taken, links to our articles on the subject, etc.) TenOfAllTrades(talk) 18:46, 25 November 2005 (UTC)
We can tell you what licenses are currently acceptable to Wikipedia, what we can't do is tell you what licences are acceptable to you. In the past, people have tried to revoke the licence because they didn't understand how many rights they were giving away. Whether or not you can use public domain may depend on which country your are in --David Woolley 19:24, 25 November 2005 (UTC)
Be sure, too, you are happy with the idea that your photo can be modified, or used by others to make money (e.g. on a postcard, or their web site, or in a collection of art work for sale). The main difference among the choices is not that you can stop this, or get any share, but whether you get credit. Notinasnaid 19:47, 25 November 2005 (UTC)
Some allow people to prevent you from using versions that they have modified. I think all allow them to be modified in ways you may find offensive. --David Woolley 22:10, 25 November 2005 (UTC)
## How can I make a small improvement in an article?
A small improvement in the formulation of Alexander's sub-basis theorem. The current formulation uses the phrase "sub-basic cover" without explanation; at first I thought it meant just "sub-basis"; but in fact it meant "cover contained (as a subset) in a sub-basis". Better for the statement to be more explicit.
Harold Hodes (<email removed - see instructions at top>)
You edit the article in essentially the same way as you edited this page. If the text is in a aubsection, there will be an edit link next to it. Otherwise use the edit this page tab. You can use help in the side menu for more more details. Please remember to say what you've done and why in the edit summary. That's particularly important if you edit anonymously, although, as you don't mind giving your name here, you shouldn't mind creating yourself an account. --David Woolley 21:46, 25 November 2005 (UTC)
## Uh... pictures not showing
Sometime last night all thumbnailed pictures on wikipedia stopped displaying on my computer. Not just on wikipedia but the commons too. The wikipedia and commons logos on the top left show, though. Now the pictures are just white blanks that have the appropriate size but nothing shows. Even full-size images don't appear, and the only way to get them to show is to view the image by itself, ie. http://en.wikipedia.org/wiki/File:CERN_Atlas_Caverne.jpg doesn't work but http://upload.wikimedia.org/wikipedia/en/8/8d/CERN_Atlas_Caverne.jpg does. Not sure if this is localised, just me or universal. Some help is appreciated. Thanks. -- Миборовский U|T|C|E|Chugoku Banzai! 21:18, 25 November 2005 (UTC)
This site is usually a good place to see how the Wikipedia servers are doing. - Akamad 06:15, 27 November 2005 (UTC)
## Formatting Help
Hi, Im trying to format my articles. I want a new section to start after pictures or tables. Right now I have to use <br><br><br><br><br><br><br><br><br><br> until I reach the end of the table or picture. Is there a better way to do this?--Ewok Slayer 21:37, 25 November 2005 (UTC)
Using <br> in this way is not a good idea, because it assumes characteristics of the output device that you shouldn't assume (and also the probable original inteneded meaning was that in Tex or nroff, in which multiple instances have no more effect than a single one). Rather than trying to control the layout, I think you should be moving the images so that they don't interfere with the text on common browsers. HTML was never intended to be a page description language and Wiki tends to be fairly true to the original aims of HTML. --David Woolley 21:59, 25 November 2005 (UTC)
• WP:FPC use a clear:all command in a br tag, but usually, having text wrap around images and tables look better, so I recommend you use it sparingly. - Mgm|(talk) 22:09, 25 November 2005 (UTC)
• Exactly what I was looking for! Thankyou. MacGyver Im using this command now: <br style="clear:both;" />
# November 26
## Help with AOL IP address issues
Ciao, and many thanks in advance for assistance. I am new to Wikipedia and have been wandering around the site, lost. I have AOL and when I created my account, negative banning comments appeared on the 'my talk' area. I created the account today and have yet to do anything but correct a typo. I read the part about AOL and the dynamic IP addresses, but is there a way for an AOL user to have a solo account? What I mean is, is there a way to have my account only be mine so that I can contribute in peace, or will this problem continue? I am sorry if this is a stupid newbie query, if there is a link or FAQ that I missed, I would appreciate some direction.
Mille grazie, Alipes 01:36, 26 November 2005 (UTC)
Alipes 01:57, 26 November 2005 (UTC)
You have successfully created an account and, at the time of writing, your talk page is completely empty. You will only see the IP address related page if you are not logged in. --David Woolley 10:11, 26 November 2005 (UTC)
## "wall of shame"
I heard there is a place where people who wrote really stupid things have them posted and I was wondering where I could find this, Thank you.
You're thinking of Wikipedia:Bad Jokes and Other Deleted Nonsense. -- Миборовский U|T|C|E|Chugoku Banzai! 01:39, 26 November 2005 (UTC)
## Help find information
How do I use this to find out what is a Real Estate Limited partnerships and what does derivaatives options mean?
I'm lost on how to use this, can you e-mail me at <e-mail removed>
Thanks,
Carla
## Film Clips on Wikipedia
A user has e-mailed the Help mailing list inquiring whether there were any film clips on Wikipedia.
I am not aware of any although I am sure that it would be possible to add it to the commons.
If you are aware of any non-copyvio clips on Wikipedia, could you please respond.
Capitalistroadster 02:11, 26 November 2005 (UTC)
There are some, though I can't say how many. One of my favorites is at Controlled Impact Demonstration (near the bottom). Most that I've seen, if not all, are in Ogg Theora format. There's a fee codec for just about every platform; I believe there are details at the link. HorsePunchKid 2005-11-26 05:09:49Z
Meta:Video policy may be of some interest.--Commander Keane 10:27, 26 November 2005 (UTC)
Yes, there do indeed exist film clips on Wikipedia - Brian0918 and I uploaded virtually all of them (I'm the one who showed him how to do convert them to ogg theora). They can be found on commons:Category:video Raul654 14:01, 26 November 2005 (UTC)
## Changing Image Description and other data
I just uploaded an image but after pressing the button to upload, I realized I made a mistake in the image description and other data. Questions:
• How can I change the write-up below the image?
• Do I have to have the whole thing deleted? then upload the same image again?
• On a previous occasion, I used the "Upload a New Version of this File", but it became complicated--I did not know if the old image was really deleted or it was just shoved off to another place; after uploading the image anew, it started asking some questions I couldn't answer...So I suppose this is not the right way to ensure that the write-up below the image is change? Walter Ching 13:58, 26 November 2005 (UTC)
The caption on the page using the image is on the page using it. The long description and the licence tags are on the File: page, which you can edit using edit this page, like any other page. The history entries for the actual image (File History) are history entries, so can only be entered when you upload a new image. Uploading a new image makes it the current image for that name, but you can still access the old versions by clicking on their dates in the File History. --David Woolley 14:51, 26 November 2005 (UTC)
Thanks a lot, David Wooley! That was helpful. Walter Ching 13:47, 27 November 2005 (UTC)
## Get Rich or Die Tryin' and Get Rich or Die Tryin' (2003 album)
Rebelduder69 (talk · contribs) cut the content of Get Rich or Die Tryin' (which was previously about the 2003 album), pasted it into Get Rich or Die Tryin' (2003 album), and has turned the original page into a disambiguation page. The problem is, this happened almost three months ago, and several users have edited both pages since then, so the edit histories are very wrong. Does anybody know how to fix this? Thanks in advance. Extraordinary Machine 14:33, 26 November 2005 (UTC)
What do you mean by, "edit histories are very wrong"? -- Perfecto 03:57, 27 November 2005 (UTC)
I imagine that he means that the article appears to have been created by Rebelduder69 on 2005-09-05, when it was actually created by 198.81.26.44 on 2004-03-04. As it is that sort of article, there is no edit summary, so it contitutes a GFDL violation as the full list of copyright owners isn't available, nor is the full History. If it had been moved properly, the edit history would have moved with it. --David Woolley 14:05, 27 November 2005 (UTC)
## Publishing a Wikipedia article for commercial purposes
Can somebody publish a Wikipedia article and sell it for commercial purposes? GFDL license it seems allow commercial use of uploaded photos. How about the text and the photos together, can they be printed and sold without any legal restriction? Thanks to whomever answers this. Walter Ching 14:41, 26 November 2005 (UTC)
They can be printed and published, but under the legal restriction that the person doing so must comply with the GFDL, which means that they must provide a copy of the approved version of the GFDL text, they must include a full list of copyright owners and a full modification history (these two tend not to be enforced because they don't work well with the nature of Wikipedia), and, if printing more than 100 copies, must also provide a machine readable editable version of the document or a web reference to such a version. (Note this is for the GFDL operated properly. I would argue that the de facto Wikipedia licence is weaker with respect to several details of the GFDL, e.g. Wikipedia doesn't provide a URL that retrieves the complete document (including GFDL, copyrights, and history) and for the parts, doesn't provide them without extraneous material (the page and form in which they are mebedded).)
Provided someone complies with the GFDL requirements on licensing, etc. they can use them, and modify them, for use in any sphere of endeavour, at least as far as copyright law is concerned, although some used might constitute defamation, or migh violate criminal law. IANAL --David Woolley 15:04, 26 November 2005 (UTC)
For offline things like magazines and books, a link pointing to Wikipedia and the GFDL along with a notice it can be edited and a list of contributors appears to be enough. If the list of contributors is particularly long, I'm sure it can be linked too. - Mgm|(talk) 23:35, 26 November 2005 (UTC)
That's the de facto Wikipedia licence, not the GFDL (that is my perception, it is not legal advice about the licensing terms). At least for the GFDL, if they modify the article, any "transparent" form maintained by Wikipedia ceases to helpful; they have to provide access to the transparent form of their modified version. The printed version is known as an opaque version in GFDL terms. (My user page explicitly gives the Wikipedia Foundation permission to relicense because I don't think that the current licence is GFDL.) --David Woolley 00:02, 27 November 2005 (UTC)
Thanks a lot to both of you, MacgyverMagic and David Wooley. Walter Ching 14:02, 27 November 2005 (UTC)
## Case for undeletion
Hello: I am the owner of a web site that previously had an article in Wikipedia. This article was recently deleted and I would like to discuss/contest this move. What is the appropriate way to do so? Thank you.
See WP:DRV for information on how to ask for a deletion review. --GraemeL (talk) 16:01, 26 November 2005 (UTC)
The place to do this is Wikipedia:Deletion review. You can also read the reasoning behind the delete at Wikipedia:Articles for deletion/(insert name of article here). If your article doesn't have such an AFD page, it was likely speedily deleted. However, unless your website had exceptionally high traffic or information that expanded the scope of an encyclopaedic article it is unlikely to succeed. --Gareth Hughes 16:10, 26 November 2005 (UTC)
Contesting that your web site deserves a spot in Wikipedia is, IMO, crass. But that's just me. -- Perfecto 03:54, 27 November 2005 (UTC)
## Book Cover Image
I created an old version of this picture File:Betrayal(LOF).jpg. I tried uploading a new one but everytime I do it only shows the old one. I tried reverting but I can't get my newone to show up. It's in the file history ones though.--User:Jedi6 November 26, 2005
You need to flush all the caches back to the server. That's typically done using one or both of control and shift to modify the browser refresh command. Most web proxies cache images quite agressively. At least here, the latest version (after a cache flush) shows a last modified date of 2005-11-26 22:32:20 and an expires date of 2005-11-27 00:13:51,
These headers on the response show the caches at Wikimedia that are being used to speed up the serving of images but also delay updates:
Server: lighttpd/1.4.7
X-Cache: MISS from will.wikimedia.org
X-Cache-Lookup: HIT from will.wikimedia.org:80
X-Cache: MISS from vandale.knams.wikimedia.org
X-Cache-Lookup: HIT from vandale.knams.wikimedia.org:80
Via: 1.0 anchor-cache-01 (NetCache NetApp/6.0.1)
I don't know what the standard is for book covers, but my personal view would be that you want to halve the size of the image before you can claim that it is low resolution, i.e. to the size at which I see the thumbnail. Also, the parenthes are normally separated from the title by a space.
--David Woolley 00:23, 27 November 2005 (UTC)
# November 27
## Adding audio samples to music bio pages
Is it possible (legal) to add audio samples to a wiki page? For example, 30 second clips of essential material of a certain band? I've seen some pages link to *.ogg files that have been uploaded to Wiki. More info would be appreciated. Thanks!
--Flunkycarter 00:06, 27 November 2005 (UTC)
I see nothing wrong linking to them, though I haven't seen it done. Submitting them as .ogg to Wiki Commons though means you're releasing it to the GFDL. -- Perfecto 03:46, 27 November 2005 (UTC)
Um, no. Commons files can be under any copyleft license - not necessarily licensed under the GFDL Raul654 03:47, 27 November 2005 (UTC)
Reply to Flunkycarter - There are some full-legnth songs uploaded to commons. You can find the master list at wikipedia:sound/list Raul654 03:49, 27 November 2005 (UTC)
As for clips of copyrighted songs without a license, that's a legally fuzzy area called fair use. See wikipedia:Copyright FAQ Raul654 03:49, 27 November 2005 (UTC)
So a copyrighted song, with the quality dramatically reduced (A low OGG bitrate, reduced in quality) and only providing a 30 sec. (reduced in quantity) sample of a copyrighted song would be allowed under Fair Use to illustrate an educational article(Wiki Article)?
--Flunkycarter 22:09, 27 November 2005 (UTC)
I don't see the point of posting snippets of audio you do not own. No one will gain anything from it except the copyright holder. I think the copyright holder ought to release the rights to the snippets himself. But that's just me. -- Perfecto 03:18, 28 November 2005 (UTC)
• The point is to enable users to understand what the article is talking about. A short-reduced quality snippet both helps to explain the topic, and benefits the copyright holder, so it definitely qualifies as fair use. Kappa 03:39, 28 November 2005 (UTC)
## how do i delete a page?
How do I delete a page, title and all? —Preceding unsigned comment added by 66.28.235.62 (talkcontribs) 06:30, 27 November 2005 (UTC)
You can't. Only an Administrator can do that. You can nominate a page for deletion, though. Titoxd(?!?) 06:30, 27 November 2005 (UTC)
I'm pretty sure you meant to delete Heather kalachman. Since you were the only editor, I've deleted it under the Criteria for Speedy Deletion. Titoxd(?!?) 06:33, 27 November 2005 (UTC)
## Wikipedia main page RSS feeds?
Is there any way to get a feed URL for specific sections of the Wikipedia main page (i.e., In the News)?
• See Wikipedia:Syndication. As far as I can tell there's feeds for today's featured article and today's featured picture. - Mgm|(talk) 10:38, 27 November 2005 (UTC)
## Creating a portal
I've been looking at some of the articles that link to Roman (a rather detailed disambiguation page with lots of links), and its history. All of the articles that I have looked at so far (maybe ten, I know it's a small sample) have very general references to "the Romans". I believe that people will continue to write "the Romans..." and link to Roman without giving it a second thought, as they should be able to do. Therefore, I now think that one possible solution is that "Roman/s" could redirect to a portal on Ancient Rome, but no such portal exists as yet.
My question is, what requirements need to be met for the operation of a portal? Would it need a maintainer, or can it be set up so that no maintenance is necessary? Is there a proposal discussion process that should be followed before going ahead?
Portals are intended to be reader oriented and Ancient Rome sounds worthy of a portal to me. Most, though not all of the portals listed at Wikipedia:Wikiportal have maintainers associated with them, though WP:PORTAL suggests that they should be set up to be low maintenance. There doesn't seem to be a formal process to go through before creating a portal and instructions for creation can be found at Wikipedia:Wikiportal. --GraemeL (talk) 14:01, 27 November 2005 (UTC)
## Why does wikipedia break my sig now?
Why does the wiki break my sig now? It only started happening recently (sometime between Nov. 10 and 22 judging from my contribs). It should look like #1 (that's copy-pasted), but wikipedia is now auto-reformatting it to #2. I assume some software change is to blame, but how can I get the desired result back?
1. Lommer | talk 21:18, 27 November 2005 (UTC)
2. Lommer | [[User talk:Lommer|<sup>talk</sup>]] 21:21, 27 November 2005 (UTC)
See WP:SIGHELP. Markup is no longer parsed within the default signature; you need to put your entire signature in the field and use "raw signatures". — Knowledge Seeker 21:38, 27 November 2005 (UTC)
Great, thanks for the quick reply. -User:Lommer | talk 21:43, 27 November 2005 (UTC)
# November 28
## How to search in textbox while Editing?
I realize there are external tools for this but I'm looking for a javascript implementation, whether a bookmarklet or something I can add to my monobook.js. There's a replace function on user scripts, perhaps there can be one for searching and highlighting or going to that place while editing. Gflores Talk 00:14, 28 November 2005 (UTC)
I don't know of one that'll take you directly to the word your searching for (I'd love to know of one too), but if you use Firefox and use "Edit/Find in this page..." (CTRL-F), then click "Highlight" on the Find toolbar, it will highlight the word you're looking for in bright yellow within the text box. You may have to scroll to find it, and occasionally I find that editing the word while it's highlighted is difficult for some reason, but you can just click the Highlight off temporarily. Hope that helps at least a little bit. — Catherine\talk 01:23, 28 November 2005 (UTC)
Good news, I've found an extension that does this exact thing (and only this) for Firefox here. Works wonderfully. Gflores Talk 02:20, 28 November 2005 (UTC)
## Wiki Definitions
There are some non-existent (red) links which seem to call more for definitions than articles, even brief ones (because there are good specialized links out there). I have a vague notion that there is a WP place for such items and that it is fact poor practice to make articles out of definitions? Is so, no? Can you point me to a how-to? Thanks, Halcatalyst 01:26, 28 November 2005 (UTC)
You're looking for Wikipedia is not a dictionary. However, depending on context, things that might seem only to require definitions can actually merit real articles. -- SCZenz 01:30, 28 November 2005 (UTC)
About 20 minutes after I log in, if I haven't physically communicated with WP, I get logged out. I might be in the middle of editing a page. (OK, I think slowly.) Is this the work of a watchdog on the WP servers, or is it some other part of my total system? I use Win XP. Is there a workaround? Thanks, Halcatalyst 01:32, 28 November 2005 (UTC)
Well, it's nothing to do with Windows XP, because I use Windows XP and this doesn't happen. The answer is around there somewhere, I remember it: check the archives. Thelb4 18:06, 29 November 2005 (UTC)
--- That's a good clue. But WP is so big the archives intimidate me. Are any search engines available to search WP only? Halcatalyst 18:40, 29 November 2005 (UTC)
## Printing problems at Crystal system entry
A Wikipedia user has sent an e-mail to the Help mailing list as follows:
In the "Crystal system entry", the last four trigonal point groups can't be printed, i;e., they are left off of a print out. They do show up just fine on the screen. I have looked at the HTML and I can not see what the problem is. I would be interested in knowing what the problem is as well as having it corrected.
I have had a look and cannot find the problem. If you can see what the problem is and can fix it, it would be greatly appreciated.
Capitalistroadster 02:17, 28 November 2005 (UTC)
• It sounds like a fairly common printing problem - web pages getting interpreted as being unusually wide by the browser and thus printed off to the side of the page. Perhaps he could try printing it from a different machine, or in a different browser, and see if that helps? I suspect it's the images in tables causing the problem, but I don't know how to deal with that... Shimgray | talk | 14:55, 28 November 2005 (UTC)
## Citing Wikipedia
How do you cite a page?
Usual answer: Go look at Wikipedia:Citing Wikipedia!
Ok, the developers have coded a new feature so we don't have to answer the age-old question. The new page is Special:Cite. However, I need some help to customize the page to give MLA, APA and other citation styles. Anyone knows what to do? Titoxd(?!?) 03:43, 27 November 2005 (UTC)
• Wow...that's the niftyest thing I've seen since wrist PDAs. Makes me wish I needed to cite sources in such a fashion, just so I could use it. Kaz 02:50, 29 November 2005 (UTC)
If you are an administrator, edit MediaWiki:Cite text. If you aren't, then make your proposed changes on the talk page and a friendly adminsitrator will do it for you (I'll do it if nobody else has when I get back from the m:Wikimedia UK meeting in London). Thryduulf 07:49, 27 November 2005 (UTC)
Um, yeah, I'm an admin, and I have in fact already changed it... I just asked here if someone wanted to help CatherineMunro and me. Thanks! Titoxd(?!?) 01:20, 28 November 2005 (UTC)
## Who are authors for wikipedia
<no contents> —Preceding unsigned comment added by 130.117.106.114 (talkcontribs)
Most people asking this qustion really wanted to ask "how do you cite Wikipedia as a source, however, the literal answer is the thousands of people whose user identities appear in article histories and the, probably even larger number of people, like you, for whom only the IP address appears. --David Woolley 14:44, 27 November 2005 (UTC)
## source cards for school project
What is the publishing company, city of publication and copyright date for the article "Military Tribunals in the USA"
You must be talking about a sub-heading in the article Military tribunal. There is no publishing company, city of publication, or copyright date for this or any article in Wikipedia. For general information on citing Wikipedia sources in school work or for any other purpose, see Wikipedia:Citing Wikipedia. Halcatalyst 04:13, 28 November 2005 (UTC)
I would say that the publication company was the Wikipedia Foundation Inc. The foundation is based in St. Petersburg, Florida, and that (or possibly where the servers are, if different) is important, as certain coyright issues depend on it (e.g. some source material may still be in copyright in the UK, where a 70 years after death rule is applied). The copyright date is the last modified date that appears at the bottom of the article. This is also important, as it determines when the copyright in anonymous contributions expires (more precisely, that is detemined by the history entry for the specific anonymous contribution).
As noted in other recent replies, there are preferred ways of citing Wikipedia, although they all include the modified date from the article. The date is particularly important because articles frequently change (and it is the existence of different versions, that is more likely to be the reason for capturing the copyright date in this case). --David Woolley 13:34, 28 November 2005 (UTC)
It's true that for legal purposes there is an organization behind Wikipedia. But the Wikipedia Foundation is not a publisher, only a host. That said, your point about the last edit date is crucial for anyone citing WP. This is somethng that many people, not to mention students, would not know. To cite properly, the date the page was last edited as well as the date it was accessed must be included. The author will be anonymous and the title will be that given on the article page. The URL must of course be given. In most cases, this will be all that's needed. Halcatalyst 02:47, 29 November 2005 (UTC)
There is now an easier way to find a citation for a Wikipedia article: go to Special:Cite and enter the title of the article, or click on "Cite this article" on the navigation bar on the left once you are at the article you need to cite. Titoxd(?!?) 02:51, 29 November 2005 (UTC)
## website author
I am doing a bibliography for a speech and I used your site as a source. Who do i put as the author?
Usually at the front; see proper citation guides here. Thanks! εγκυκλοπαίδεια* (talk) 02:52, 28 November 2005 (UTC)
Please see Wikipedia:Citing Wikipedia. There's a "Cite this article" link on every page as well. -- Rick Block (talk) 02:55, 28 November 2005 (UTC)
Woops, I wished I made that suggestion, but I used to rely on the Purdue site myself, so that is why I recommended it. No harm done. εγκυκλοπαίδεια* (talk) 02:56, 28 November 2005 (UTC)
It's really very simple. No Wikipedia articles have authors as such. All are officially anonymous collaborations. So, for the author, use Anon. This is acceptable in any system of citation. Halcatalyst 02:53, 29 November 2005 (UTC)
You can also use "Wikipedia contributors" as the author for your citations. See Special:Cite to obtain a citation for the page you want to cite. Titoxd(?!?) 02:58, 29 November 2005 (UTC)
--- Special:Cite or "Cite this article" in the Toolbox sidebar of every article is a great resource. I'm glad to have found out about it. Halcatalyst 18:54, 29 November 2005 (UTC)
Articles do have authors. It is one of the stated principles of the GFDL that it exists to ensure that authors of a document receive due credit. In particular, if you use Wikipedia content in a context that requires a copyright licence, the GFDL requires you to list all the authors of the article. --David Woolley 19:07, 29 November 2005 (UTC)
## Hey
I created this template here for new people who'd be pretty pissed off when there recent article gets deleted. Any thoughts? Should it even stay? εγκυκλοπαίδεια* (talk) 02:52, 28 November 2005 (UTC)
I fear its lack of specificity will often make things worse. -- SCZenz 03:01, 28 November 2005 (UTC)
Yep. εγκυκλοπαίδεια* (talk) 03:10, 28 November 2005 (UTC)
• Apart from the fact, VFD was renamed AFD a while ago, I agree with the others, maybe use something similar to {{db}} and leave a space for the poster to fill in a reason. That would make it a lot more useful. Also, I don't think the welcome needs to be in the same template. There's enough newbies who already have been welcomed. I think those need to be separated. - Mgm|(talk) 08:26, 28 November 2005 (UTC)
## Listen! Oyez! Oyez!
Vandal ova here: User:James of Wales. Put a template on already. Looks like the Wikipedia is Communism dude impersonating whoever the guy was who created this site, I have to remember his name. At any rate, delete him! εγκυκλοπαίδεια* (talk) 03:10, 28 November 2005 (UTC)
Pardon me? -- Perfecto 03:21, 28 November 2005 (UTC)
Never mind, an admin has taken care of the problem. εγκυκλοπαίδεια* (talk) 03:37, 28 November 2005 (UTC)
What? I did what? I'm innocent! I didn't do it!!! :P Titoxd(?!?) 17:37, 28 November 2005 (UTC)
## Wierd article
I ran across William D. Ferris while trying to fix the hockey dab page. I'm pretty sure there's something wrong with it, maybe WP:VAIN, but I really can't put my finger on it. Help from a more experienced user would be helpful, along with recommendations for next time. D-Rock 05:58, 28 November 2005 (UTC)
It could be vanity, but more important (as WP:VAIN says) is what's in the article. It has a lot of information that is not notable or encyclopedaic, and could legitimately be cut down considerably. In fact, it may be that there is nothing that's notable enough in there at all, so you might consider AfD'ing it after looking more closely and some research (a goggle search/maybe). -- SCZenz 06:26, 28 November 2005 (UTC)
The asteroid 10937 Ferris named after him is easily verifiable outside his website. I'm sure this will survive AfD. The list of comets and near-earth objects also prevent a merge. (I'm sure I've seen weirder articles.... though because I'm here more often.) -- Perfecto 01:11, 30 November 2005 (UTC)
## why does melting point determination must be finely powdered?
(No question)
• Welcome to Wikipedia. Please see the instructions at the top of this page, so that you can effectively get help. This page is for questions about Wikipedia. Notinasnaid 13:10, 28 November 2005 (UTC)
## How do I get wikipedia articles to appear in google searches?
eg, If I do a google search for my friends band called "juju space jazz", it doesn't come up, but if I do a search on "Simon Posford" (the producer) it comes up with ";;;Simon Posford - Wikipedia" etc —Preceding unsigned comment added by Zangtubba (talkcontribs)
The reason for this is very simple - Wikipedia does not have an article on "Juju Space Jazz", but it does have one on Simon Posford. You could write and article on Juju Space Jazz by clicking the link, but you should only do so if they meet the crieria for inlcusion at WP:MUSIC, otherwise your article is likely to be deleted. Note that your article will not be found in a Google search until Googlebot indexes the page and it is incorporated into the search database. This usually takes a few days, but can take much longer than that. Thryduulf 17:35, 28 November 2005 (UTC)
## Micronations
Good Day
I have visited Wikipedia often and have read many extremely well written articles, however, today I stumbled into something quite confusing. I am reading up on Micronations, the reason being that I am aspiring to be granted political asylum by a certain country, but should it nor be granted I would like to consider alternatives. To me it is a vital issue, an issue that would affect my family and myself in a most serious manner. I ask for your serious consideration of my question(s)
My specific question centers around the entry about the dominion of Mechizedek. I read through the contents as in the Wikipedia entry, then noticed a section called "talk" clicked on it and entered into a discussion that, put simply, astounded me. I believe wholeheartedly in UNBIASSED facts, and thought that this was what Wikipedia was about, but after reading the entire thread (a few times over to understand the implications) I was forced to conclude that whoever was responsable (in this case rather unresponsable..my opinion) certainly was NOT looking for factual or even balanced entries. There seemed to be decided "camps", each with a very unforgiving and seperate agenda. Now, at the risk of dragging my question out. I shall just ask it straightforward.
In reference to the specific entry abdout the dominion of Mechizedek, why can there not be an independant review of the entire entry, by people that have a PROVEN ability to be unbiassed?
I would like to qualify my question further by equating my thoughts..
If certain individuals of a country commit "crimes"..I put this in inverted commas because, what is described as a crime in some countries would not neccesarilly be so in others...eg. drinking a alcoholic beverage in USA is legal(at the moment, but not in the past)...elsewhere it would be VERY illegal (at the moment, but not neccesarilly in the past) Thus, the impression that I get is that OPINION should be disregarded when FACTS are at stake. The facts should be balanced and given with impartiality.
Again with reference to the Mechizedek site, I found it absolutely bewildering to read through a series of claims, counter-claims and at the end of the day...absolutely no consensus and leaving me no other option but to revert to trusty old GOOGLE to try and find FACTS and decide for myself.
Please help me on this issue, I am not too familliar with the editing and administration of the wikipedia articles, but I would like to believe that someone would clear this queation up for me.
Kindest Regards immigrationissues2002 Caracas, Venezuela
Well, it's Wikipedia policy to present a neutral and objective (non-biased) point of view (see WP:NPOV). However, as far as I can see, this widely viewed as a totally moronic rule that no one follows. You may want to check Wikipedia:General disclaimer. While in my opinion Wikipedia is fairly obective and accurate - there are certain instances where biased articles can be found. It's one of the drawbacks of Wikipedia being the "free encyclopaedia". Izehar 19:38, 28 November 2005 (UTC)
• At a quick glance over the article: The Dominion of Melchizedek does not "exist", at least not as a nation - it holds no territory, it is recognised by no governments. It is not a nation - it cannot grant you asylum. Nothing that describes itself as a micronation is a "real country" in the way that, say, Venezuela is, and many are little more than either personal amusements or attempts at fraud. Please bear this in mind.
• The article itself is an attempt to conform to a "neutral point of view" - reflecting that there are those who insist that the Dominion exists, and that various countries have done things that might look like diplomatic recognition - but, you're right, is probably a bit wishy-washy. The key is, though, that the two camps are divided over the nature of the "FACTS", so an unbiased observer is going to decide one way or the other... and then by doing so they fall into one camp, meaning the other side won't accept the conclusion. Here we get an impasse. Shimgray | talk | 19:48, 28 November 2005 (UTC)
Thank you Izehar and Shimgary for your comments. Could you perhaps tell me how I can contact the editor(s) of that specific entry. I think they need to get told a few things in no uncertain terms and be explained about the reasons why someone might want to read their entries. I won´t enter into their food fight, just explain in a nice way that what they write actually has consequinces far beyond an on-screen message. immigrationissues2002
You can contact them by leaving a message on the article's talk page at Talk:Dominion of Melchizedek. Izehar 20:02, 28 November 2005 (UTC)
My guess is that the major problem with that article is that it starts off "...is a micronation..." To someone very familiar with the concept - which will include every author of the article - "micronation" automatically means "not a real country". However, to the casual reader, "micronation" can be interpreted - as I think you did - as being "a kind of country". When you know that a micronation isn't a country, the article seems a lot less vague; if you think it is a country, it's pretty bizzare.
The reason for this is that if you think it's a country, the claims and counterclaims seem to be disputing whether the country exists. Since a micronation exists as soon as someone claims it does, though, its existence isn't actually disputed in the article - it's whether it's what it claims to be that is disputed. Does that make sense? Shimgray | talk | 20:03, 28 November 2005 (UTC)
# November 29
what kind of lawyer should i get for at fault cases?
• Please read the notice at the top of the page. We request that you ask factual questions at the Reference desk. Deltabeignet 04:12, 29 November 2005 (UTC)
## Numbered list items with multiple paragraphs
Is this possible? What I want is
1. Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
2. Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
(except moreobviously as a list)
I tried this (standard wiki syntax):
1. Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
1. Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
obviously wrong. I tried a hack (inserting <P> where I want a break, but leaving on the same line):
1. Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
1. Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
Any suggestions? Thanks, pfctdayelise 05:50, 29 November 2005 (UTC)
1. This is a test.
2. This is also a test.
The syntax:
#This is a test.
#:
#:
#:
#This is also a test.
Ξxtreme Unction {yakłblah} 00:54, 30 November 2005 (UTC)
In case anyone else is interested, me and Extreme Unction have puzzled out a solution. Forget wikisyntax and use <ol> (ordered list) in combination with <br&;gt or <p> tags.
eg.
<ol>
<li>
Item 1 blah blah blah
<p>
Item 1 is so important it needs two paragraphs
<li>
Item 2 is also very important
<p>
So it has two pars as well
</ol>
-->
1. Item 1 blah blah blah
Item 1 is so important it needs two paragraphs
2. Item 2 is also very important
So it has two pars as well
You can also close your <li> tags if you want, it's better html I think but it works anyway. <ol> MUST be closed. pfctdayelise 02:44, 30 November 2005 (UTC)
## Preferred spelling?
Just wondering what spelling is preferred, American, or English (UK, Canada, etc), as in color or colour? Thanks!
• Nevermind, forgot to look in the FAQ
## How can I change my user name?
How can I change my user name? --Yochai Twitto 10:20, 29 November 2005 (UTC)
See Wikipedia:Changing username. As a general tip, if you don't know how something works on Wikipedia, you can try typing "Wikipedia:Whatever you're trying to do" in the search bar - if we don't have a howto article with that exact title, there will probbaly be a redirect to the howto -- Ferkelparade π 10:49, 29 November 2005 (UTC)
## Tagging Images
Hi I was wondering what tag is appropriate (if any) for scans of video games manuals. Also is the same tag appropriate if its taken from a pdf file found on the games disc? Thanks. Examples File:Alterac-warcraft2-with-orc-symbol.jpg - User:UnlimitedAccess
{{copyvio}} or {{db}}. I would say that both cases would be copyright violations. --David Woolley 14:07, 29 November 2005 (UTC)
## How to remove rel=nofollow?
Hi,
I have my own copy of WikiMedia installed, and I'd like not to have rel=nofollow tag along with my external links. Whrer can I change the script settings to restrict placing this tag?
Thanks.
function makeExternalLink( $url,$text, $escape = true,$linktype = ) { $style =$this->getExternalLinkAttributes( $url,$text, 'external ' . $linktype ); global$wgNoFollowLinks; if( $wgNoFollowLinks ) {$style .= 'rel="nofollow"';
Remove rel="nofollow" :)
Hey, guys. I'm a pretty regular article editor, but I've run into problems in the past with uploading images, so I'm looking for a few tips in general, and if it's OK to upload this picture which is a part of this article from vatican.va. Thanks, JHMM13 16:12, 29 November 2005 (UTC)
I doubt it's public domain. Vatican-produced material is covered by copyright, unlike in the US where it would be public domain. There is no explicit copyright notice, but I doubt one is needed. The image is of an artwork, suggesting that under Bridgeman Art Library v. Corel Corp. we would be allowed to reproduce it if the original was public domain - but we can't tell when it was painted (probably 1915-1930) or when the artist died, which is usually the key factor in European copyright laws (and the Vatican certainly has them - it's a signatory to Berne and the UCC). Shimgray | talk | 19:07, 29 November 2005 (UTC)
Tell it to me straight, Jonny Esquire. JHMM13 22:04, 29 November 2005 (UTC)
The straight answer is "no... but I am not a lawyer". It's possible it's sort-of-free, at least good enough for our purposes, but we'd need more information to be sure. Sorry. Shimgray | talk | 14:31, 30 November 2005 (UTC)
## How to link event to city?
I was looking for information about the Treaty of Lausanne, but didn't know what it was called exactly, so I opened the Lausanne article, first. However, I didn't find a reference to the treaty there.
How should I add a link to the treaty to the Lausanne article? Of course, I could write something about it in the History section, and link to it in the "See also" section, but I wonder if there should also be a disambiguation remark at the top of the Lausanne article, since "Lausanne" could also refer to the Treaty of Lausanne, just like "Maastricht" could refer to the Maastricht Treaty. --Benne 16:44, 29 November 2005 (UTC)
You could use the {{for}} tag. Basically you would just put {{for|the treaty of the same name|Treaty of Lausanne}} at the top of the Lausanne article. It would expand to:
For the treaty of the same name, see Treaty of Lausanne.
Dismas|(talk) 20:51, 29 November 2005 (UTC)
## Help
How do i find out the information that you put on a bibliography card?
On the side of every article, under the heading Toolbox, there is a Cite this article link. Clicking that will give you seven forms for citing a Wikipedia article. For more information see Citing Wikipedia. Canderson7 20:49, 29 November 2005 (UTC)
## Picture borders
How do I put a border on a picture? Izehar 21:20, 29 November 2005 (UTC)
{{border}}, IIRC. ナイトスタリオン 21:32, 29 November 2005 (UTC)
Or use [[File:imagename.jpeg|frame|Your caption goes here]], as explained at Wikipedia:Extended image syntax. - IMSoP 23:58, 2 December 2005 (UTC)
## licensing?
HI, if I have made a mistake in the licensing of a photo how do I correct it? and if I took the Photo and release all right would (GFDL-self) be the correct licensing? --LPW 21:50, 29 November 2005 (UTC)
{{GFDL-self}} would be valid and acceptable to Wikipedia. It doesn't release all rights. Only you or your lawyer can say whether it is acceptable to you. IANAL TINLA. --David Woolley 22:26, 29 November 2005 (UTC)
See WP:ICT#For_image_creators for a list of licenses you could use that would be acceptable to WP. Also, please consider uploading to Commons instead. This will make your image available for use by all wikimedia projects, not just the English 'pedia. pfctdayelise 23:00, 29 November 2005 (UTC)
## Wikipedia as a Press Source for an offline publication
I'm sorry if this is obvious or answered in some FAQ or guidline page that I missed but I've been trying to put in a template on the Oxford Street talk page that notes that the article was used as a press source in Time Out London this week. I'm pretty useless at filling out templates as it is but thought I'd give it a go. Problematically, I couldn't seem to find one that allows me to skip putting in a URL or website. There is a Time Out London website, but they don't have the article on there. I've put it down on the Wikipedia as a press source listings anyway so someone might put it in for me but it would be nice to find out how it's done for the future. Thanks in advance. Jellypuzzle 22:16, 29 November 2005 (UTC)
As predicted, it's been done for me on Talk:Oxford_Street. I suppose I can just copy what they've done now. Jellypuzzle 23:17, 29 November 2005 (UTC)
## Infoboxes
When editing articles about fictional objects, I frequently use tables based on Infoboxes (though not the actual box itself) to summarise the information. See either the box on this page: Springfield (The Simpsons), or a couple of (hypothetical) examples on the user page (User:Smurrayinchester/Infoboxes). But, I just realised that this could potentially be confusing to some users, making a fictional thing seem 'real', even just briefly, and am no longer sure whether I should keep them. Should I? smurrayinchester(User), (Talk) 22:28, 29 November 2005 (UTC)
• Aristotle said fiction$was truer than history because it opens up mind and experience to more possibilities. I agree, so I applaud what you're doing. Analysis and information about human creations is just fine. Halcatalyst 22:46, 29 November 2005 (UTC)$ Actually, he said "poetry." But don't worry, because per Wallace Stevens poetry is the supreme fiction. Halcatalyst 22:46, 29 November 2005 (UTC)
Thanks! You've cleared my conscience! smurrayinchester(User), (Talk) 10:38, 30 November 2005 (UTC)
## Portals
Okay, I'm really confused here. What is the difference between a category and a portal? If it's layout then how come the links on the main page (culture, geography, etc.) point to categories rather than portals, even though they have the same layout as a portal?
Also, where can I find a comprehensive list of portals? I've tagged Category:Wikiportals, Category:Portals, and even Wikipedia:Portal, because I found them confusing, and, frankly, a mess. Category:Wikiportals gives me links to several portals, but also "subcategories" which are just the category links from the main page. Category:Portals gives me an alphabetical listing, but when I click a letter, just shows me a list of various categories, and no portals. Wikipedia:Portal has 2 lists, which are inconsistent, and I suspect neither is complete. Some portals listed as complete are red, and yet some work when I click them on the other list.
Can anyone explain this more clearly for me? —Preceding unsigned comment added by 82.7.125.142 (talkcontribs)
A Category is a group of articles with similar aspects; the large ones are managed by WikiProjects. A Portal is the "main page" of the Project (like the cover of a book). A list of Portals can be found at Wikipedia:Portal#All existing Wikiportals. Unfortunatly, there is not much consistency and Portals are created on whims. Izehar 23:14, 29 November 2005 (UTC)
I'm not surprised you are confused. Consider Category:Cricket. They have transcluded the Portal onto the category page.--Commander Keane 05:54, 30 November 2005 (UTC)
## Alphabetical Sections
I'm working on this article, and it seems obvious to me that it would be better if the contents list went crossways rather than downwards because the sections are A, B, C etc.
Is there a straightforward way of achieving that? I realise I could go:
A | B | C
...and so on, but that seems a bit of a palaver. Besides, even then I wouldn't know how to supress the automatic contents list.AndyJones 23:20, 29 November 2005 (UTC)
Try using the template {{TOC}}. pfctdayelise 23:41, 29 November 2005 (UTC)
{{compactTOC}} also works nicely, I think. —Josiah Rowe (talkcontribs) 23:53, 29 November 2005 (UTC)
# November 30
## What template made this ->
Thursday
2
October
11:27 UTC
I'm curious. -- Perfecto 00:53, 30 November 2005 (UTC)
Where did you see it? You might figure out who added it and ask them. -- Rick Block (talk) 02:05, 30 November 2005 (UTC)
## Plagarism
While doing some research about Expedition Robinson, the European version of North America's Survivor, I noticed that second paragraph from the Overview section of the Expedition Robinson article is plagarized from the third paragraph on this website [2]. I'm not sure how to go about reporting plagarism so someone can clean it up, but I am not familiar enough with the European version of the game to correct this. The best I could do is reword it. How should this be taken care of? Jtrost 00:57, 30 November 2005 (UTC)
Thanks for reporting a possible copyright violation. This isn't actually a case of plagarism though. Answers.com is one of many sites that mirrors Wikipedia content. It is copying from us, not the other way around. This is allowed however as long as it notes where the information came from. If you spot another copyright violoation in the future, you can follow the directions at Wikipedia:Copyright problems to deal with the issue. Canderson7 01:20, 30 November 2005 (UTC)
Thanks for the clarification. I didn't look at the copyright notice. Jtrost 01:49, 30 November 2005 (UTC)
Only, it seems the article has undergone some major edits since Answers.com last took a capture of its content. jnothman talk 02:21, 30 November 2005 (UTC)
Hi, The other day I added this category, [[Category:Historical pederastic relationships]] to the article on George Gordon Byron, 6th Baron Byron and got a redlink that leads to a page claiming that "Wikipedia does not yet have a Category page called Historical pederastic relationships." However, the same category link leading from Marsilio Ficino works perfectly well and leads to the correct category page for this very category. Can you help fix this problem? Haiduc 01:32, 30 November 2005 (UTC)
That is very odd. I compared the two category links and saw no difference, but by copying the text of the working link and replacing the text of the one that didn't work, I somehow fixed the problem. Here's the diff: [3]. Canderson7 01:41, 30 November 2005 (UTC)
The broken revision includes a control character called "PDF" shown after the category name. You probably inserted it by accident, Haiduc. The character shows when editing the broken revision in Opera and does not work in Firefox, which is why Canderson seems to be confused as to how he changed the same thing into the same thing.] jnothman talk 02:29, 30 November 2005 (UTC)
Thank you both, I could tell that there was something strange there but as I do use Firefox. . . Haiduc 02:32, 30 November 2005 (UTC)
Thanks for clarifying, jnothman. Canderson7 02:47, 30 November 2005 (UTC)
I have just realised what the "PDF" character may have been doing there. Someone else fixed the same in anther article, where Unicode control character "LRE" preceded the text, and "PDF" followed. [4] indicates that LRE is "Left to write embedding", indicating that the following text is to be left-to-right (like English), whereas PDF ends such a marked passage to "pop directional formatting". Do you use any Hebrew or Arabic, Haiduc? jnothman talk 02:49, 30 November 2005 (UTC)
There's more on this at Wikipedia:Village pump (assistance)#Design changes? Disappearing ".7C" signs in category sections when using Safari. The mediawiki software was changed fairly recently to include these characters when displaying the list of categories. My guess is Haiduc yanked a category from a displayed list (and the yank included the invisible bi-di indicators) and when pasting it in another article included the invisible characters without realizing it. I suspect the developers might be interested in this. -- Rick Block (talk) 02:32, 1 December 2005 (UTC)
## paid
do i get paid if i constantly supply wikipedia with information and various articles that are of public interest?
Short answer: no. Long answer: Wikipedia is run entirely by volunteers and funded entirely by donations, so there aren't any paid positions, except for Chief Technical Officer. Titoxd(?!?) 01:45, 30 November 2005 (UTC)
Technically, there is nothing preventing you from getting paid, but there is nothing requiring you to get paid either. I suppose if you're a really good editor, Jimbo Wales might send you a small sum of money as thanks, but it would be entirely a humanitarian gesture and not to be taken as any kind of official salary. If you really want to be employed by the company that owns Wikipedia, you could try asking Jimbo Wales directly. I can't speak for him. — JIP | Talk 15:17, 2 December 2005 (UTC)
## Image problem
I've recently nominated a few pictures on Ifd, because they are in violation of the original owner's copyright. It clearly states it cannot be used without prior permission by the webmaster. I have yet to see this proof. In addition, I've attempted to use one of the photos, and recieved this response, from the very same user that defended his actions. A couple of minutes ago, I came across Copyright Violations, and saw that I could nominate for immediate deletion.
Any help? What should I do? Thanks in advance. Pacific Coast Highway|Spam me! 11:27, October 2, 2014 UTC (purge)
The image should either be listed at WP:CP (not ifd), or simply tagged following the instructions in the orange box at WP:CP. If properly tagged any admin going for deleting speedies will find it and it will disappear quickly. — Sverdrup 11:19, 30 November 2005 (UTC)
The guy even blanked the ifd template on one of them. Pacific Coast Highway 01:29, 1 December 2005 (UTC)
## Merging two articles
I posted comments on Talk:Ushabti, but I'm afraid my comments may not be seen if I just leave them there. It seems to me that the Ushabti article should either be deleted or merged/redirected into the Shabti article. The trouble is that I'm not sure how to proceed. I tried looking through the help pages, but it's hard to find the information I need in the limited time I have (my lunch break at work). Could someone tell me what I need to do, or do it for me in a way that will allow me to see how it was done? I see this sort of thing occasionally and am never sure what to do about it. Unfortunately, I'm rarely able to spend more than a few minutes at a time helping out with Wikipedia, so I tend to look for projects I can complete quickly. --CKA3KA (Skazka) 20:46, 30 November 2005 (UTC)
## template
I created a template to write categories without having to type 'category' (I always spell it 'cateogyr' because of typos) and on the first page I used it, the template didn't work. Why didn't it work? Is it because of subst? Maybe that I used subst: and User: together? It just appeared on the screen as {{subst:User:Thelb4/cat|British record producers|Parsons, Alan}}. Thelb4 21:04, 30 November 2005 (UTC)
I tried again, it worked now.--Patrick 01:42, 1 December 2005 (UTC)
• Wouldn't it be easier to just use the preview button and correct your typo before saving. This template is so much longer, I'd make tons more mistakes when using it than the regular code. - 131.211.210.16 09:08, 1 December 2005 (UTC)
• I realised that and will not use it again, but I'm curious as to why it just appeared like that. Thelb4 19:18, 1 December 2005 (UTC)
# December 1
## wikipedia
What does wikipedia mean?
Wikipedia is a papier-mâché word formed out of wiki (i.e. a group of Web pages that allows users to add content) and -pedia (from encyclopaedia). In other words, it means the free encyclopedia; free meaning open for anyone to edit. Izehar 00:03, 1 December 2005 (UTC)
It's an ancient Celtic word that roughly translates to "look up the corresponding article" :P -- Ferkelparade π 00:05, 1 December 2005 (UTC)
## cascading William F. Gibsons, redirects & disambigs
There currently are 4 William F. Gibson pages, at least:
1) redirect William F. Gibson => redirect William Ford Gibson
(fixed) William F. Gibson => redirects to William Gibson (novelist)
2) redirect William Ford Gibson => article William Ford Gibson (writer)
(fixed) William Ford Gibson => redirects to William Gibson (novelist)
3) disambiguation William Gibson
(OK) William Gibson => disambig page
4) article William Ford Gibson (writer)
(OK) Doesn't exist.
How do I set it up so that a search on William F. Gibson gets straight to 4) article William Ford Gibson (writer), without having to go through intermediary pages such as 2) and 3) ?
--Kessler 00:22, 1 December 2005 (UTC)
Things ^ up there do look a bit confusing however, the main article you that want to go "straight to", William Ford Gibson (writer), doesn't exist. Before someone fixes the redirects problem, are you satisfied with the existing article title William Gibson (novelist)? --hydnjo talk 01:18, 1 December 2005 (UTC)
Oops yes I didn't check my link: I was referring to William Gibson (novelist). And altho I haven't read that article in detail it looks OK to me: my concern right now is with the redirecting -- I'd like my William F. Gibson search to get to that article direct. --Kessler 01:28, 1 December 2005 (UTC)
OK now (that part anyway). --hydnjo talk 01:51, 1 December 2005 (UTC)
## Identifying New Articles I have created
I can easily get a list of all my contributions, but these don't identify which of them was a new article. I haven't created many, but there are some. Where do I find this info? JackofOz 01:06, 1 December 2005 (UTC)
Is this a hard question, or am I not being clear? I want a list of all the new articles that I have ever created. How do I find it? JackofOz 09:14, 1 December 2005 (UTC)
It's a hard question. I don't think you could do it easily without an SQL query (and then I'm not sure how easy it would be...), which could be done either through a developer or by adding a new special page to the next version of MediaWiki... I may be wrong, though. jnothman talk 10:12, 1 December 2005 (UTC)
Thank you. This is very odd. They're all listed on "My contributions", just not identified as new. Minor edits are still marked m, so how come new articles are not marked N, as they are on Recent Changes or my Watchlist? It just seems so intuitively obvious to me that it should be that way, that, not being an IT person, I don't understand why it isn't. JackofOz 12:40, 1 December 2005 (UTC)
I am something of an IT person and I also can't see why Wikipedia can't store information about which contributions are new article creations and which are merely edits. Wikipedia already saves information about the contribution's date and its user in some database table, it shouldn't be too much difficulty to use an additional column, or a flag bit in some other column, to store whether the contribution created the article or edited it. Of course this would mean changes to the MediaWiki software, but it shouldn't be too hard for the developers to implement. However getting it done retroactively seems too much to hope for, as then the whole database would have to be queried thoroughly, which could take days, possibly even weeks. — JIP | Talk 15:14, 2 December 2005 (UTC)
I couldn't find a bug related to this, so I filed a new one at Bugzilla; see Bug 4150. — Catherine\talk 01:28, 3 December 2005 (UTC)
## Wikipedia for Windows/Linux?
I doubt this is the place to ask, but I dunno where one should:
Might someone point me at a link for installing the Wikipedia's data on one's machine and setting it up to be accessed via web server? In other words, something like "Download the SQL export, import it into MySQL, then download any of these three software packages: X (for PERL), Y (for php), and X (Java), then plug in the corresponding front end code, found (here), using any web server software which supports CGI-BIN."
Something like that. Pretty please. 209.33.24.118 02:57, 1 December 2005 (UTC)
What's an actual link for instructions to dump and import the data, and a link to mediawiki? Kaz 03:10, 1 December 2005 (UTC)
The pages you want are:
-- jnothman talk 04:07, 1 December 2005 (UTC)
UltraMegaThanks! Kaz 06:49, 1 December 2005 (UTC)
## Random Logouts
I AM SO EFFING SICK OF BEING RANDOMLY LOGGED OUT! The above was (as that ip always is) me. Kaz 03:00, 1 December 2005 (UTC)
• Click "Remember me" (ie cookies) You'll need a database dump and import, and a mediawiki installation. Not that hard. Wikibofh 03:05, 1 December 2005 (UTC)
I always have Remember Me clicked, and have cookies fully allowed on my machine as well. This is a problem which has grown gradually over the last year or two...I used to stay logged in for weeks or months, then sometimes it would only be days or weeks before a random logout, then it was hours or days, now it's every few hours, occasionally it's just minutes apart. Kaz 17:36, 1 December 2005 (UTC)
• Go to My preferences and see if you have remember across sessions checked. Until I checked that button I had the same problem--Dakota t e 19:48, 1 December 2005 (UTC)
## Server locations
Where is Wikipedia run? It is strange to see that the last time a page was edited was tomorrow morning.—Preceding unsigned comment added by 68.119.44.82 (talkcontribs) 03:07, 1 December 2005 (UTC)
what is the edition of wikipedia?
Maybe Wikipedia:Citing Wikipedia would help? -- SCZenz 03:53, 1 December 2005 (UTC)
## My "test" has been removed?
"This message is regarding the page Opium. Thanks for experimenting with Wikipedia. Your test worked, and has been removed. Please use the sandbox for any other tests you want to do. Take a look at the welcome page if you would like to learn more about contributing. Thanks.
Sycthos 04:24, 1 December 2005 (UTC)"
Why thank you Sycthos, bot or mod, comparable as though they may be. I feel all welcome now. I guess adding Edgar Allan Poe to the list of famous opium users is stubid.
More like a complaint than a question, but couldn't find a complaint section, which annoys me further. Pssh, copyleft people and mistakes? Get out of here.
—Preceding unsigned comment added by 80.160.181.90 (talkcontribs) 05:40, 1 December 2005
The complaints section is Wikipedia:General complaints. You could also have left a message on User_talk:Sycthos to ask about the message. He (an ordinary editor, like you) may have just made a mistake. I'll look more and then tell you what I think happened. -- SCZenz 06:00, 1 December 2005 (UTC)
After looking, I am not sure if you edit was right for the article or not, but it surely wasn't vandalism or a newbie test. I'll leave Sycthos a message asking him to be more careful. I'm sorry about the mixup, and I hope very much that you continue to edit Wikipedia. -- SCZenz 06:06, 1 December 2005 (UTC)
• Did you provide a source of the information, when you made that addition? - 131.211.210.16 09:10, 1 December 2005 (UTC)
• Sorry about the mishap. I did not thoroughly research Edgar Allen Poe before reverting and thought this was not a good-faith edit. Please re-do the addition to Opium. Also, please note that the notice was based on a template and the exact wording may not be accurate. Again, sorry about the issue. Sycthos 22:34, 1 December 2005 (UTC)
## I'm having a hard time adding an image
I'm having an incredibly tough time adding a simple Temple University logo to my Temple football page. I just keep getting that box to ask me to fill out the information and when i do that the logo doesn't show up in any context but a word file. As far as copywright because it's a generic logo, it's considered "fair use" so that shouldn't be a problem. A similar example is listed on the Villanova University page with its logo. Thanks for any help you can give me. Mike
If you've already uploaded the image to Wikipedia servers here, then follow the Wikipedia:Picture tutorial to show it on a page. Gflores Talk 06:23, 1 December 2005 (UTC)
Be sure that if you claim "fair use" you know what it means. It is a specific legal term, meaning you are breaking copyright in a way that's allowed; you must give credit to the copyright holder and a valid reason for the claim of fair use. Notinasnaid 08:50, 1 December 2005 (UTC)
• And don't forget to add a source. - 131.211.210.16 09:11, 1 December 2005 (UTC)
## Seleucia disambiguation
I was just passing this page, and it seemed ripe for a bit of editting, as the part I wanted turned out to be the last sentence. I thought: "aha, this really is a geo disambiguation page!" But after I started to work on it, I discovered that the several paragraphs had actually been separate pages, and are now combined (having redirects from them) -- no sections, it was all one big amalgam (so I made them sections now for clarity). What's the procedure for "undoing" the consolidation? It turns out there are nearly 100 links to this page, so not for the faint-hearted! I've got no vested interest in the content. (Given directions, though, I'll gladly do the work.) William Allen Simpson 07:32, 1 December 2005 (UTC)
Well, as long as the redirect pages weren't AFD'd with a result of merge (and it doesn't seem they were), I think you can just copy-and-paste the content to the various articles you think it should be in (noting where it came from, for GFDL purposes). However, you'd then have to make sure that all the existing links were to the relevant article. It is a lot of work, and the way it is now probably isn't the end of the world. In any case, you should wait for more comments in case I haven't thought of something. -- SCZenz 09:03, 1 December 2005 (UTC)
Thanks! No more comments were posted. Followed the plan, am about 1/3 way done with the links. Some of the ecclesiastical links are not clear (and already have unknown links to a Council at Seleucia), so somebody more familiar should update them as found. William Allen Simpson 00:25, 2 December 2005 (UTC)
## We have an illegal immigrant!
Re: Parellada. This article is part of the English wikipedia, yet it's written in (95% sure of this) Spanish. Should the article be deleted, translated or moved? It c ertainly needs copyediting and wikifying... but there's not much this poor old monoglot can do right now. Should I be posting this message somewhere else? Is Articles Requiring Attention just for important articles, for example? *Satis 11:15, 1 December 2005 (UTC)
The topic of the article *was* a Spanish family name (non-notable, only person with that name mentioned was some backwards village mayor in the 17th century); Parellada is, however, also a type of grape, so I wrote some basic information about that and made it a {{wine-stub}}. ナイトスタリオン 12:19, 1 December 2005 (UTC)
Were the article more notable and longer, but nonetheless in a language other than English, it may be virtuous to list it on Wikipedia:Requests for translation. jnothman talk 12:22, 1 December 2005 (UTC)
## Random Table Error
On loading my user page, the page normally appears as two tables set out side-by-side like columns (as it should). However, about 1 in 4 four times when loading the page, the tables stack on top of each other instead of side by side. The error normally fixes after refresh, but oddly, the error only occurs in Firefox, not Internet Explorer! Is it a fault with the browser, or the table layout? smurrayinchester(User), (Ho Ho Ho!) 15:46, 1 December 2005 (UTC)
Perhaps update to Firefox 1.5, if you haven't already and see if it fixes it? Gflores Talk 20:54, 1 December 2005 (UTC)
Have similar problem using Netscape 7.01 with Yahoo! I suspect the coding has become so complicated that sometimes our old favorites just miss a tag ... sort of like us old farts! :-) ttocsmij 08DEC05
## Sandbox?
Hiya, I'm a college professor, and I encourage my students to be critical thinkers regarding Wikipedia and the internet as I think Wikipedia and the internet have similar strengths and weaknesses. As such, I have changed a page in a crazy way (and then immediately change it back).
I got a message to do this in the sandbox, but have since been unable to find said sandbox--can anyone point me in the correct direction? Can I do it without my students realizing it is "fake"? I really want them to think critically about what they read and putting that Abe Lincoln was the son of teenage mutant ninja turtles and seeing that live on the screen (which we immediately change and talk about ethical communication) has gotten the point across more clearly than anything else I've tried. Thanks!
Technically, one of the rules of Wikipedia is 'Do not disrupt Wikipedia to make a point'. However if you are looking for the sandbox, it is here: WP:Sandbox. It won't just contain your information though; if you want to do that you could try starting a user account (Click 'Create user account') at the top of the screen, and then use your User Page for that sort of thing. smurrayinchester(User), (Ho Ho Ho!) 16:49, 1 December 2005 (UTC)
If you mean one of these messages:
Thanks for experimenting with Wikipedia. Your test worked, and has been reverted or removed. Please use the sandbox for any other tests you want to do. Take a look at the welcome page if you would like to learn more about contributing to our encyclopedia. Thanks.
Please stop adding nonsense to Wikipedia. It is considered vandalism. If you would like to experiment, use the sandbox. Thank you.
They are the first and second level vandalism warnings. The first may be skipped if the change to the article looks to have been deliberate disruption, rather than a naive user experimenting. After the third one, your account, or failing that, your IP address becomes eligible for progressively longer blocks on editing. After the fourth you become eligible for listing as a known vandal. In principle this could progress up to permanent banning of the whole sub-network from which you are operating, and/or contacting the abuse department of your service provider. Most people get bored before then. --David Woolley 18:05, 1 December 2005 (UTC)
I think the point that you are making is an excellent one. All too often people complain at the editability of Wikipedia, as if that makes it useless, and the rest of the internet doesn't mirror the same faults (only larger). And it ignores the point that if it wasn't editable, it wouldn't exist. But, on the other hand the aim of Wikipedia is to provide an ever improving encyclopedia, not to be an experiment in social anarchy. (There are such experiments: Wikipedia is only one of many wikis). And there are two problems with using this method. One is that many people here find the addition of bad information, even temporarily, deeply offensive. It happens all the time, but that doesn't make it better. Second, people resent the extra time they may have to spend monitoring the changes that might arise from your lessons (yes, they will check the changes, and then examine the other changes you have done when they find you are adding nonsense, to make sure other articles aren't damaged): time which might be spent in improving articles rather than fire fighting. Hence, you will find Wikipedia is not without its defences, and you do invite increasingly severe blocks to your editing, as described above. Getting your students to write an essay on what they think will be the short, medium and long term effects of Wikipedia might be a good way to get them to think, once they understand something of how it works. Notinasnaid 20:17, 1 December 2005 (UTC)
If you want to show the risks in using Wikipedia, you can use purely passive methods. Just use the article history, and, in particular, you can use the compare versions options to create a URL that shows exactly what changes a vandal made, or to show the changes made during an edit war. (Please don't use this on edits that created or removed a copyright violation.)
Any high profile article (e.g. one that has been featured) will show lots of vandalism that you can select from, and almost any controversial article will show edit wars. --David Woolley 23:14, 1 December 2005 (UTC)
## Tables
I am in no way code-literate (other than what i've picked up through copying, pasting, and changing the text contained therein) as far as tables go, so if someone could take a look at Apollo Sunshine (album) and tell me why the date "2003" under "Apollo Sunshine Chronology" is bold, i'd really like that. a whole lot. jfg284 you were saying? 20:30, 1 December 2005 (UTC)
It's not bold to me, nor should it be. Gflores Talk 20:46, 1 December 2005 (UTC)
that's what i thought, too. but on two of my browsers, it reads with the 2003 as bold but the 2005 as normal. and it was frustrating the hell out of me. oh well.jfg284 you were saying? 20:55, 1 December 2005 (UTC)
At first I thought you were crazy and then I viewed it in IE and it was bold! :) I fixed it now. The new album infobox template should prevent these problems from happening again. Thanks Jfg284. Gflores Talk 21:06, 1 December 2005 (UTC)
excellent. thanks a bunch.jfg284 you were saying? 21:12, 1 December 2005 (UTC)
I don't know whether you saw what was done to fix the problem, but what had happened was you opened a cell with ! instead of |. The difference between these is that | defines a normal "table data" cell, where as ! defines a "table header" cell. In an ordinary table, the latter would usually be found across the top or down the left to indicate that the cell contained a heading and not data, so this cell is often formatted bold. See Help:Table.
And Gflores, although I thought that was the case, I didn't know where to find the correct difference in the history because you didn't use an edit summary. Please do. With every edit. (I notice you have generally used none.)
-- jnothman talk 21:49, 1 December 2005 (UTC)
## Mental Imagery Articles
Hello,
I am a student at Harvard College, a research aide in the Stephen M. Kosslyn Neuropsychology Lab, and the creator of the user "KosslynLab".
This summer, in my capacity as an employee of the Kosslyn Lab, I prepared and posted a cluster of articles about Mental Imagery, Motor Imagery, Visual Imagery, and Auditory Imagery. The articles were adapted from a Nature article by Kosslyn, Thompson, and Ganis, all of whom gave me permission to post the content on wikipedia. I also received permission via email from Nature to post the content.
I was dismayed to find that the articles that I posted were recently deleted. Users worried about copyright violations and that the content constituted "original research". I apologize if I violated any wiki regulations - I am a new user and I certainly have much to learn about the wiki world. However, since I do have permission to post this content from all parties involved, it is a shame that the world no longer has access to it.
I would like to repost the articles in a form acceptable to the wiki community. Can you give me pointers about how I might do so?
Thanks,
KosslynLab
Hello, KosslynLab.
1. The only article you have edited is Auditory imagery. At the time of your last edit, the page looked like this. The page is original research (see also Original research), and Wikipedia only allows actual facts.
2. Don't worry about not realising that this is not the wiki-way; you can still contribute to that article with actual facts, as you seem to know a lot on the subject.
3. If the pages are on the Internet, you may link to them an External links section (see Wikipedia:How to edit a page#Links and URL for the how-to).
Thelb4 20:51, 1 December 2005 (UTC)
Hmmm... I certainly made all four pages that I mentioned. See here.
If there was a page that you created that has been deleted (but it meets that standards for inclusion, ie it's not orgianl research) you can ask an admin to restore the article. Maybe you were not logged in when you made those other pages, so they don't show up in your contributions.--Commander Keane 21:15, 1 December 2005 (UTC)
Edits to deleted articles don't show up in your contributions (logged in or not). To request a review of the deletion, please see Wikipedia:Undeletion policy. -- Rick Block (talk) 01:11, 2 December 2005 (UTC)
## How does each traditon define the purpose of baptism
This isn't an appropriate question for the helpdesk. Please ask at the Reference Desk and be more specific. jnothman talk 21:51, 1 December 2005 (UTC)
## HTML to Wiki
Is there a HTML to Wiki translator anywhere? --Member 23:37, 1 December 2005 (UTC)
See Wikipedia:Tools/Editing tools#From HTML. jnothman talk 23:43, 1 December 2005 (UTC)
# December 2
## Lists: columns and numbered bullet points
Is there an easy way to split a list into two (or more) distinct columns? I have been editing the planemo article and the list is far too long to go down one side of the screen.
Additionally, is there any way to maintain the number bullet points down a list when one of the numbered points is then broken down into further bullets? e.g.
1. Mercury
2. Venus
3. Earth
• Luna
1. Mars
Here "Mars" is given the number 1, and not 4 as it should be.
You have a problem in your markup: the line with Luna starts with : which indicates indentation, rather than the nesting of a list. The correct markup is:
#Mercury
#Venus
#Earth
#*Luna
#Mars
As regards your second question, there is a description of what to do at Help:List#Multi-column numbered lists. Basically you need to use two concepts:
• HTML lists which start at a given number, eg:
<ol start="111"><li>a
<li>b</ol>
gives:
1. a
2. b
• Emulating columns with a table (see example at linked page).
-- jnothman talk 01:39, 2 December 2005 (UTC)
## Old version a .jpg and new verison a .gif
I made a smaller (in kb) and easyer to see version of File:Communistpartyrunstates.jpg (link). The problem is that if i try to upload a new version, the fact that the current is a .jpg and the new is a .gif conflicts, so is there any way to update it or do i have to upload the new then delete the current one. --ThrashedParanoid 03:01, 2 December 2005 (UTC)
As the old image gave you the idea to upload this one, I think it would be a GFDL violation to delete the old version. Can't you just upload your gif and tell the uploader to put it at File:Communistpartyrunstates.jpg? - Mgm|(talk) 05:55, 2 December 2005 (UTC)
This is not as simple as it seems as the JPG version claims to be based on a PNG version, and has no other copyright information and the PNG version has been deleted, so the PNG version now has an invalid copyright status. I cannot find the deletion debate record for the PNG version. JPG is certainly the wrong format. PNG is possibly better than GIF except for some limits on browser support.
Also the link for the proposed new version doesn't lead to an image. If that is just a simple oonversion to GIF, it shouldn't be used to replace the existing higher resolution image. However it was created, it will need valid copyright status information for the underlying map. --David Woolley 11:18, 2 December 2005 (UTC)
The old JPEG says it will be deleted very soon unless its copyright status is cleared up. So your GIF must be deleted too, unless you can solve this. Notinasnaid 11:52, 2 December 2005 (UTC)
Note: I added the {{nolicense}} flag when I discovered that the licence trail was broken. There are, however, two ways in which the new map could be based on it: one is to manipulate the actual image, in which case there is a copyright dependency, and the other is to use the facts that it conveys, in which case the problem is that this image also needs to be flagged with {{unreferenced}} (note that you are not allowed to use Wikipedia items as sources in this second context).
Without more information about the PNG version, I don't know how the JPG version was derived. Unless the PNG was deleted for copyright violation, it may be necessary to re-instate it to maintain a complete edit history. --David Woolley 12:29, 2 December 2005 (UTC)
OK. The talk page for the image gives a good URL for the GIF version. The GIF version does have a copyright problem because it is derived from something else that has a copyright problem. The cleanup of the image has also made the country boundaries uneven. I think you need to start from first principles and re-source the data about the countries and the obtain a base map with known, and usable, copyright status. The captioning is also misleading in that it seems to imply that the states are currently communist. --David Woolley 13:07, 2 December 2005 (UTC)
I've now found the correct link to the upstream version and propagated its licensing and copyright owner information, although I'm still wary about the copyright on tbe base map. As the upstream version is .PNG and therefore lossless, it should be updated and the JPG version abandoned. --David Woolley 13:48, 5 December 2005 (UTC)
Excellent, it appears my clipboard is a little messed up, so it didnt paste the correct URL the first time (wierd, rather confused about it myself). So should we just replace the links on the Communist state wiki page to use this image?
After you've updated it; the JPG has an extra country. --David Woolley 15:44, 5 December 2005 (UTC)
Okay, added Somalia, Nicaragua, and Benin to the PNG version, all that is left is to have the redudnant .jpg deleted. --ThrashedParanoid 15:55, 5 December 2005 (UTC)
## Edit count
I notice a lot of people 'advertise' their edit count. How is this statistic obtained? can someone tell me how I can find out mine (for my own vanity/interesting). novacatz 04:02, 2 December 2005 (UTC)
The simplest method is Kate's tool. Annoyingly, this is currently unavailable, and you have to count your edits manually. That is, go to your contributions page, view 500 edits, and find how many pages you can get through, 500 at a time. Then cut down to 100 at a time, etc, until you have a close count. jnothman talk 04:11, 2 December 2005 (UTC)
## WP Search Engines
Are any search engines available to search WP only? Halcatalyst 05:07, 2 December 2005 (UTC)
Yes, Google for one. If you put "site:en.wikipedia.org" (without the quotes) into the search field along with the words that you're searching for, Google will only return results that are in the English Wikipedia. Dismas|(talk) 05:12, 2 December 2005 (UTC)
• There's also WikiWax which I can recommend. - Mgm|(talk) 05:53, 2 December 2005 (UTC)
Clusty has a special Wikipedia "tab". - IMSoP 23:43, 2 December 2005 (UTC)
A9 also has a "Wikipedia" check box; checking two boxes will display results side by side. — Catherine\talk 01:40, 3 December 2005 (UTC)
LuMriX is similar to WikiWax.
Thanks to all who responded. The WP link on my Firefox search window is most cool! Halcatalyst 04:00, 3 December 2005 (UTC)
## monobook.js
How do I edit my monobook.js? When I go to "http://en.wikipedia.org/wiki/User:Bmdavll/monobook.js" I get an error message: The database did not find the text of a page that it should have found, named "User:Bmdavll/monobook.js". Trying to edit that brings me to a new page. Do I need to create it first? Bmdavll 06:22, 2 December 2005 (UTC)
It's a strange error message, but yes, just edit the page. Maybe see Help:User style and User Scripts project. What's important is what you see at http://en.wikipedia.org/w/index.php?title=User:Bmdavll/monobook.js&action=raw&ctype=text/javascript&dontcountme=s as this is what is loaded by the browser. jnothman talk 06:50, 2 December 2005 (UTC)
Yes, you need to create it first if you haven't created one before (I'm not sure how strange the error message is), just like creating a user page, talk page, and other pages in your user space. Of course, aside from you, only administrators may create/edit your monobook.js file. So if you haven't created one, it's extremely unlikely anyone has already created one for you without telling you, so yes, you should go ahead and create it. — Knowledge Seeker 07:11, 2 December 2005 (UTC)
• Of course it didn't find the page. If it doesn't exist yet, there's nothing to find. - 131.211.210.14 09:16, 2 December 2005 (UTC)
What's strange are the words "should have found" in the message, and its appearance in a preformatted text box which requires horizontal scrolling. jnothman talk 10:53, 3 December 2005 (UTC)
I think the preformatted box is a product of how .js files render, as I tried to fix that when I made the edit to the message but it didn't work. Thryduulf 13:18, 3 December 2005 (UTC)
The database did not find the text of a page that it should have found, named "\$1".
This might be because no page has yet been created with this name, in which case you can start it by clicking the "edit this page" link.
If it is a recently changed page, trying again in a minute or two will usually work. Alternatively, you may have followed an outdated diff or history link to a page that has been deleted.
If this is not the case, you may have found a bug in the software. Please report this using the procedure given at Wikipedia:Bug_reports, making note of the URL.
Thryduulf 12:44, 2 December 2005 (UTC)
Whwn I try to log in or register it tells me I must have cookies enabled which they are. I am in Malaysia since early November and just today got internet access which might be the reason but I can't see why it would be. There are testy messages on the talk page of this ip and I sure would like to distance myself from them because they are not mine. I am a registered user with over 800 edits and I have never vandalised. Any user here got any advice. I would appreciate any input. thank you.--219.93.174.106 09:08, 2 December 2005 (UTC)
MediaWiki:Loginend has been moved to MediaWiki:Signupend because of some redesign, but in the process the username instructions disappeared of the login screen. Can someone fill me in about what happened in this redesign and why the mover blanked it after moving?
• Forgot to sign. - Mgm|(talk) 16:32, 4 December 2005 (UTC)
## Always Quickly Booted After Signing In, Even Though Cookies Allowed
• Did you select: "remember my password"? - Mgm|(talk) 11:16, 2 December 2005 (UTC)
• Yeah, I always check the "remember me" box when I log in and I appear to be signed in when I initially access the home page. I tried accessing Wikipedia on the same computer, but using Mozilla Firefox instead of Internet Explorer - this had no effect.
See discussion at Wikipedia:Help Desk#Random Logouts above: it might help. (and always sign your contibutions, please, using four tildes, i.e. ~~~~, which automatically generates a signature) SiGarb 18:02, 10 December 2005 (UTC)
• After logging in, clicking "My Preferences," receiving the "Not Logged In" error message for about ten repetitions, it finally allowed me to see the "My Preferences" page. The "Remember Me Across Sessions" box was already checked. I tried saving my preferences again to be sure, but got the "Not Logged In" message when I clicked the button. I'm very confused. - 67.142.130.23 01:16, 11 December 2005 (UTC) (Login is "Raoul-Duke" - can't stay logged in to save)
## Force link to open in new window
Anyone know how to do this pleae ? In my wiki I have several external links, and the back button on the navigator doesn't always work. I know the user can force a new window (eg using IE via a right-click, open in new window) but I would like to make this automatic. Many thanks in advance Hilary
Do you mean you want to change how links work in a Wikipedia article? I don't think that would be appreciated. Notinasnaid 14:46, 2 December 2005 (UTC)
No, I agree that wouldn't be good practise. Actually this is a problem on a wiki I've done for work purposes so style is under my control
Very common question, this one; it is, therefore, on the MediaWiki FAQ, which points you to meta:Opening external links in a new window. Note that this isn't really the right place to ask this - see http://mediawiki.org for where to find help with MediaWiki. Also note that whenever this has come up on the development mailing lists, people have pointed out fairly forcefully that you shouldn't really force such behaviour on your users; they can right-click and do it themselves... - IMSoP 23:41, 2 December 2005 (UTC)
## Targets in Articles
Is it possible to place a target between Headers in articles? If so, how?
Many thanks,
Yesselman 14:54, 2 December 2005 (UTC)
What do you mean by "target"? — JIP | Talk 15:05, 2 December 2005 (UTC)
What he means is <a name="fred"> in old HTML dialects, and the same with id in modern ones, so that you can then have [[#fred]] as on on page link to it or [[Article#fred]], as an off page one, but without having ====fred====, or any other heading like display of fred.
He shouldn't be trying this on Wikipedia because it will confuse other editors, especially if he clashes with a heading added later, and because it will represent information that is lost when the article is printed.--David Woolley 17:52, 2 December 2005 (UTC)
Section headers are can be targetted, but since such links aren't updated as moved articles are people are discouraged to link to such a header and are recommended to just link to the main article instead. - Mgm|(talk) 16:35, 2 December 2005 (UTC)
I agree with all the caveats already stated about why it might not be a good idea, but if you do want to do it, I believe you can use <div id="foo">...</div> to do this. Just beware of using the same ID more than once - like when someone put such a tag in a template which was used multiple times on one page... - IMSoP 19:40, 2 December 2005 (UTC)
## Unable to view deleted edits
I recently deleted a vandalism redirect for the second time. However, when I visit the deleted redirect, it merely shows "View or restore 2 deleted edits?" without making it into a hyperlink. Thus I am unable to actually view those edits, even though I am an admin. Viewing deleted edits of other pages works fine. Here is the link to the deleted redirect: [5]. What is the reason for this? — JIP | Talk 15:04, 2 December 2005 (UTC)
• I'm not sure, but I have a sneaking suspicion devs have removed it entirely from the database, so we can't view any of it. - Mgm|(talk) 16:39, 2 December 2005 (UTC)
• I came looking for help and clicked on your link and I saw the page big bold many worded article name. Now how did I do that, shouldn't been able to. Everything here is schized today.--Che Perez 22:04, 2 December 2005 (UTC)
## <noinclude> tag?
What does the <noinclude> tag do? (For example:Template:Nasdaq) Shawnc 16:10, 2 December 2005 (UTC)
In a template, if you wanted to include something that shouldn't be in the actual article (like a category of that type of template, or template usage instructions), then you would surround it with <noinclude> and </noinclude>. Likewise, a template that puts something in the article (a category for example), you would surround it with <includeonly> and </includeonly>. Thelb4 16:17, 2 December 2005 (UTC)
I see, thank you for the response. Shawnc 16:26, 2 December 2005 (UTC)
Is there a page in Wikipedia that documents this feature? I know there's http://meta.wikimedia.org/wiki/Help:Template#Noinclude_and_includeonly at Meta, but I don't see it here. — Catherine\talk 01:56, 3 December 2005 (UTC)
## What is going on?
Every other edit I make makes a stupid error message pop up; and then I get logged out sometimes. I ruined my edits of Military ranks of Mexico, and I was hoping that someone could help. Is there a problem with Wikipedia's servers? εγκυκλοπαίδεια* (talk) 19:57, 2 December 2005 (UTC)
It happens from time to time. You should still be able to go back, while keeping your edit text and hitting Save page again. Gflores Talk 22:24, 2 December 2005 (UTC)
Until then, it just sucks, huh? :). εγκυκλοπαίδεια* (talk) 02:49, 3 December 2005 (UTC)
If you wantt to buy Wikipedia a server farm, I'm sure they'd be happy... jnothman talk 13:02, 3 December 2005 (UTC)
Can someone direct me to the help page or policy regarding links? The reason I ask is this: I often find articles cluttered with links that aren't beneficial. Some seem to double bracket every word in an article that may lead to another article without regard if it adds anything but color to the topic. Other than clutter, I think that spurious linking likely adds to the tasks of the disambiguation project. Likely this is a common question, and I'll be glad to RTFM if anyone can tell me which M to R. =) --Bad carpet 22:17, 2 December 2005 (UTC)
Sure, it's in the Manual of Style. Gflores Talk 22:22, 2 December 2005 (UTC)
Thanks! --Bad carpet 22:30, 2 December 2005 (UTC)
## Template
How do you make a deletion template that isn't for speedy deletion?--Anti-Anonymex2Come to my page! I've gone caliente loco! 23:04, 2 December 2005 (UTC)
You mean {{AfD}}? Says something about "This page is being considered for deletion in accordance with the deletion policy"? Those are the only two deletion templates I know of. Be sure to read the instructions on the AfD page before marking a page for deletion. Hermione1980 23:12, 2 December 2005 (UTC)
You're best off reading the 3-step process instructions at Wikipedia:Articles for deletion#How to list pages for deletion, but first read the Wikipedia:Deletion policy. Because this process takes three steps, there have been a few scripts made to speed it up. See the User Scripts project if you are interested. jnothman talk 13:01, 3 December 2005 (UTC)
## Signature
What just happened to my signature? It was fine several weeks ago. -- King of <font color="red">♥</font> [[User talk:King of Hearts|<font color="red">♦</font>]] [[Special:Contributions/King of Hearts|♣]] [[Special:Emailuser/King of Hearts|♠]] 23:46, 2 December 2005 (UTC)
Wikipedia:How to fix your signature. Thryduulf 00:21, 3 December 2005 (UTC)
# December 3
## Deleted article
I decided to make my first contribution to wikipedia. Created an article on Richard Gregg (an empty link refered from Simple living). After being put to quick deletion after 2 days was deleted. How do I refute the deletion criteria? I was given a reason (not important enough). I explained why I didn't agree. The article was deleted without further explaination. Is this a normal way of acting here? I dont want to defend here the relevance of the article only ask if this could be considered abuse of deletion powers and if not how a person can start the discussion about the relevance of the article? —Preceding unsigned comment added by 81.193.82.160 (talkcontribs) 02:55, December 3 2005 (UTC)
• I hope someone can answer this question. Gregg was the first American to develop a substantial theory of nonviolent resistance (see his The Power of Non-Violence, 1934). Martin Luther King, Jr., said this was one of the five books that most influenced him. Halcatalyst 04:08, 3 December 2005 (UTC)
• The link to MLK Jr. (unmentioned in the article) convinced me the speedy was an error. However, it should clearly assert the importance of the subject, and be expanded. The connection to MLK in particular should be added and cited from a reputable source. -- SCZenz 06:44, 3 December 2005 (UTC)
• The article stated he was an author who coined a word, thus the person who tagged it thought it was just another person. If you had included the fact he started the theory of nonviolent resistence you would've established notability and avoided it being deleted. It's all in how info is presented. Perhaps Wikipedia:Stub will help. - Mgm|(talk) 09:58, 3 December 2005 (UTC)
• I am the poster of the original article. Congratulations! The article is republished and in a much better form, restoring my faith on this comunity. However one question remains: an article was deleted without any attempt of discussion. Even if I did attempt to refute the criteria and start a discussion my reasoning was no answered. The relevance of the article was clearly stated on the external links and on the original article himself (was an empty article coming from another entry and he coined a philophical word). I know vanity can be a problem, but deleting a first contribution without giving further explainations on the discussion can be also a form of vandalism.
• See WP:CSD for a list of the very precise rules that govern when an article can be speedily deleted. Except for the specific cases described there, deletion is a much more involved process (see for example WP:CP which covers copyright problems and WP:AFD which covers the normal, slow, deletion process). RJFJR 17:06, 6 December 2005 (UTC)
Hi,
1... I made some minor alterations to the Down Syndrome page and was wondering how I let anyone know that the source of my information is already contained in an existing external link? I know it is a requirement to provide the sources so that it's not simply me voicing off.
2... I also made some minor changes to the Down Syndrome page just before signing up, is there anyway to associate the earlier change with my new identity?
Thanks Donald.
Hello, Donald.
1. I think that the best thing to do with Down Syndrome is just put the external link again at the bottom (unless it already is, in that case you would move it from external links to sources).
2. I don't think that associating changes is possible. (It could be done by developers, but their service is currently inactive.)
Thelb4 08:18, 3 December 2005 (UTC)
Hi,
I've just left it in the external links, as there are no sources listed for the page.
Thank you, Donald.
Sources is a proposed new name for References, and I proposed it precisely because people confuse references and futher reading. The article doesn't have a References section either. I think you should start such a section and put your source in there. There are only three inline sources, so you might as well add the others as well. At least that will start the article towards being properly sourced.
I'd also suggest that you consider a change to Harvard referencing. Wikipedia can't link those well but it is much easier to quickly see what source was used for a particular fact, and to identify and repair all instances of broken links when a page gets moved. (You should use a full citation, e.g. as produced by {{Web reference}} in Sources/References, so that web resources can be re-located if they move. (That would be desirable for all the External links, whether or not they are sources, but there are a lot of them.)
A change to Harvard style requires consensus from everyone who has provided inline references, but as there are only three, that ought not to be too difficult to achieve. --David Woolley 10:00, 3 December 2005 (UTC)
Hi again. That was much more difficult than I anticipated.
Could you please check the page and see if it is what you wanted - I'm still not sure if I fully understood your direction correctly - I checked out the Harvard link - but it doesn't really tell one how to cite a web page.
I realised you asked for consensus, but I have no idea from who or how to get it. The only one I 'moved' was the book author, the others I left in tact, but marked them by numbers so the reader could cross reference them to it's source, under the Source heading. You'll see what I mean when you see it.
If I've done it wrong, please make at least one correction to act as a guide for me to fix the rest.
When I respond to your comments here, I'm doing it via the page editing feature. Is this the correct way to do it?
Thank you,
Donald.
I've done one. The Harvard reference for that would be (Urqhart 2005). Sometimes you have to improvise the author, e.g. use the company. The accessed date is important, because web sites change easily. Also, good web references are often copies of journal articles, and should be referenced as such.
The problem with explicit link numbering is that it becomes difficult to maintain as the page is updated. There's also an expectation that the links will link to the full citation.
By the way, I would try and find a better source than the one used in that first reference. It looks like a secondary or tertiary source that is tainted by really existing for commercial reasons. The web design is horrible, too. You should really be looking for ones aimed at the medical profession.--David Woolley 15:20, 3 December 2005 (UTC)
LOL. I've copied the page so that I can work on it on Monday and reversed the changes I've made already. BUT how do I get the permissions?
"A change to Harvard style requires consensus from everyone who has provided inline references, but as there are only three, that ought not to be too difficult to achieve. --David Woolley 10:00, 3 December 2005 (UTC)"
Thanks Donald.
Firstly, a move to Harvard style is just a suggestion, although one other advantage is that it will print much better becasue the URLs won't get expanded at the point of hte citation. Also, agreeing on a change of style applies to any change of style, not just one to Harvard.
I think you only need agreement amongst people who have provided in-line citations, so one approach is to search the history to find who added them, and ask on their talk pages. The other approach is to simply propose the change on the article's talk page and then wait to see if anyone objects. In both cases, no response after a reasonable tiime ought to be OK. --David Woolley 08:49, 4 December 2005 (UTC)
## Displaying East European characters
User Larry sent the following question to the Wikimedia Help Desk.
I run Windows Me and InternetExplorer 5.5, and have full set of Arial Unicode MS. I can display every Latvian, Romanian, and Croatian character properly when going to ordinary Eastern European and Baltic web pages, but many characters do not properly display on English Wiki pages about foreign languages. Can anyone help?
His two problems are Windows ME and Internet Explorer. Windows ME is really just a version of Windows 98 and it doesn't have native Unicode support. IE adds Unicode support, but its font handling isn't compliant with the W3C standards. Specifically, it will not fill in gaps in the fonts that it has chosen, even when another font does have the required glyph.
Windows XP is a Unicode based system, and seems to have somewhat better font selection processing, although I have a feeling that it is still flawed. I think almost any other GUI web browser than IE is likely to work better.
Although I haven't experimented with this myself, he might be able to create a monobook.css file that specifies fonts that work better for the pages that he uses, although he will still be at the mercy of people who think they know better than Wikipedia and specify fonts explicitly in the pages. --David Woolley 10:25, 3 December 2005 (UTC)
## List of names of people living in villages of Dumri Block
...is probably not a good title for an article. ;) Seriously, though, if you're looking for factual information, try the Wikipedia:Reference desk. If not, clarify your question. -- SCZenz 09:55, 3 December 2005 (UTC)
## Wikipedia in the press
There was an article about Wikipedia in today's Helsingin sanomat. Is there a place in Wikipedia where I can translate the article to make it available for other Wikipedians to see? — JIP | Talk 12:28, 3 December 2005 (UTC)
Given that the article will be copyrighted, no. If it weren't, you could put it in your own userspace. [[Sam Korn]] 12:37, 3 December 2005 (UTC)
But you should give a listing and summary at Wikipedia:Press coverage#December. jnothman talk 12:51, 3 December 2005 (UTC)
## How do I link a picture Directly from the Wikipedia Commons?
I decided (a couple of weeks ago) to add an image of my own Mangle to the article about, well, mangles. I've never uploaded an image before and Wikipedia's help page adviced I upload it to the Wikimedia Commons, which I duly did under commons:Mangle.jpg.
When I tried making an image link to Mangle.jpg, however, another image (File:Mangle.jpj) resident on Wikipedia itself blocked it. Can someone explain how I'd write the image link so that I bypass this image and go directly to the one on the Commons? commons:File:Mangle.jpg doesn't work, and I can't find information on this anywhere. (BTW, the blocking image is up for deletion soon so it's not a big issue for this article, but I'd like to know for the future.) --Birdseed 13:38, 3 December 2005 (UTC)
you can't. Local wikipedia images override commons ones. Always check if there is a resident file before uploading (or do what I do and make highly descriptive and long filenames). Reupload the image on commons and then ask for the first to be deleted. By the way you can direct link (without displaying) by writing [[:commons:File:Mangle.jpg]] which makes commons:File:Mangle.jpg. Or else, just wait for someone to delete the local file (which is going to be deletable soon, a week after Nov 29). Broken S 15:10, 3 December 2005 (UTC)
This seems to be a feature that wikipedia could benefit from having - it's not likely to be the only time something like this has happened. Where do I request its addition? --Birdseed 15:32, 3 December 2005 (UTC)
http://bugzilla.wikipedia.org/ Broken S 16:03, 3 December 2005 (UTC)
• Why would you want to if it can be avoided by using a filename which isn't blocked? - Mgm|(talk) 00:43, 4 December 2005 (UTC)
Because (a) it seems a waste of time to check every time, (b) "Mangle.jpg" is a better file name than "Mangle1.jpg" (or whatever you can find that isn't blocked), (c) someone might afterwards create a file on Wikipedia (if I understand things correctly) that will block the commons image inadvertedly, and (d) Why the earth not? There are hundreds of only marginally useful features in the wiki software, this would certainly be one of them.
--Birdseed 11:55, 4 December 2005 (UTC)
I am trying to disambiguate Pantheon to Pantheon, Rome in the timeline Template:Roman Empire by the usual piping Pantheon. However, this edit breaks the formatting of the rest of the table. Is this a bug in EasyTimeline or am I doing something wrong? Kusma (talk) 15:26, 3 December 2005 (UTC)
You could ask Erik Zachte, he wrote EasyTimeline and is very friendly. It worked when I did a similar edit to another timeline, so I don't know what the problem is.--Commander Keane 17:30, 3 December 2005 (UTC)
I have asked this question on Erik's talk page. Thanks for pointing me there, Kusma (talk) 18:04, 3 December 2005 (UTC)
This bug seems to be independent of what you're trying to do: changing "Gallic wars" to "Gallic warsa" also messes up the picture! jnothman talk 01:05, 4 December 2005 (UTC)
## Template II
How do I make a template?--Anti-Anonymex2Come to my page! I've gone caliente loco! 16:31, 3 December 2005 (UTC)
Go to Template:Nameoftemplateyouwanttomake. Edit as you would any page. Save. Now you have a template, and if you named it "Nameoftemplateyouwanttomake", all you have to do is add {{Nameoftemplateyouwanttomake}} to a page. jfg284 you were saying? 16:35, 3 December 2005 (UTC)
For a more detailed look at the syntax and use of templates, see Help:Template, Wikipedia:Template namespace, Wikipedia:Templates. jnothman talk 17:10, 3 December 2005 (UTC)
Usually, a template is just a table, saved in the template namespace.--Commander Keane 17:13, 3 December 2005 (UTC)
## Displaying Superscript and Subscript on top of each other
How can you do this? My signature shows a small try but the problem is pretty obvious. --Worthawholebean TalkContribs 17:53, 3 December 2005 (UTC)
I found the way to fix it. You have to set margin-right to the same value you set left to. --Worthawholebean TalkContribs 19:39, 3 December 2005 (UTC)
The only legitimate way of doing it is with maths mode, but that is expensive, because it generates images, so should be reserved for real mathematical contexts. It also isn't going to respect user font sizes, which means it is undesirable from an accessibility point of view. No use of CSS should affect the meaning, and, in some contexts, it will be ignored, anyway, so CSS tricks shouldn't have a place outside of user space. $Base^{Super}_{Sub}$. --David Woolley 19:57, 3 December 2005 (UTC)
Your way to fix it, Worthawholebean, has issues: because you are working with pixels, it is highly dependent on the font-size and browser implementation. On normal size your sig looks wrong in Firefox. It looks alright in Opera, but not perfect. The Zoom function in Opera works differently to IE & FF, so it zooms alright in Opera but not in the others.
One way to make sure that things alight correctly on the left is to use absolute positioning within a relatively positioned box. But when I tried this I got browser-dependent results, so I'll back away from that.
But I realised then that I could do similarly (a floating box) but make use of <br> and line-height control. So it's a mess of fidgety CSS, but the following works quite nicely in Firefox and Opera (not in Windows, so can't test IE):
Your sig <span style="position:relative;margin-right:3.8em;font-size:80%"> <span style="position:absolute;left:0;line-height:90%;top:0">contribs<br>talk</span></span> text afterwards.
Which gives:
Test with text above
Talk
text afterwards.
Test with text below.
To explain some possibly unfamiliar CSS: an absolute object is positioned against its outer relatively-positioned element. "margin-right: Xem" sets where the text afterwards appears. The unit em is measured as 1em = height of full letter in current font. The nbsp is there because if there is nothing in the absolutely-positioned element, Firefox acts strangely. The necessity of "left:0" is again because FF acts strangely without it. "top:0" is not necessary, but you could use it to adjust the vertical position of the small text, noting that it is positioned differently in different browsers (somewhat lower in FF than Opera). The line-height then sets, as a percentage of font-height, effectively the distance between the top line and the next.
Enjoy! jnothman talk 12:24, 4 December 2005 (UTC)
Hmmm So this worked nicely as long as I didn't save it. Now that it's saved, it's buggy in both Opera and Firefox. Any suggestions from CSS experts? jnothman talk 12:26, 4 December 2005 (UTC)
Lemme try some experimenting. This paragraph is ment to show how the sig will look in the middle of a parahraph. Once I finsh typing this, that will be pretty obvious. worthawholebean
contribs talk
18:28, 4 December 2005 (UTC) Now I am trying to show how a line under the signature will look, as well as how that spacing compares to normal paragraph spacing, which should be shown as well. Now, the problem is that the space under the sig is too large. Can anyone help fix this?
## Edit summary
On any edit page (the one I'm typing on, even), the words Edit summary have been split. The edit is on the same line as the typing box (squeezed into the side), but the summary is where it should be, underneath the box. I don't want to bring this up on Bugzilla, as I don't want to give an e-mail address. Thelb4 22:11, 3 December 2005 (UTC)
I can't replicate your problem: Edit summary appears to the left of its textbox. jnothman talk 01:02, 4 December 2005 (UTC)
Sounds like a browser problem to me. Which one are you using? Firefox works well for me. It's free. Halcatalyst 04:29, 4 December 2005 (UTC)
Opera works well for me. It's also free. I also know its web address and you got Firefox's web address wrong. But if you look at the top of the page, this HelpDesk is not a soapbox. jnothman talk 05:24, 4 December 2005 (UTC)
I'm using IE 6 on Windows XP. Is that any help? Thelb4 08:57, 4 December 2005 (UTC)
Does it help in what sense? In one sense: no, I can't replicate the problem in IE 6 on Windows XP either; I don't know what it is. Is it on particular pages, or all edit pages? In another sense: no, using IE 6 on Windows XP is unlikely to help you in general. jnothman talk 09:32, 4 December 2005 (UTC)
# December 4
## how cars work
That's not much of a question, but the correct place to ask it is the Reference Desk. But your answer would be found by following links from the car article. The car is made up of lots of things that work together, so you may want to look at the internal combustion engine article. There is also a lot of information elsewhere on the net, for instance at Howstuffworks.com's auto channel. jnothman talk 07:29, 4 December 2005 (UTC)
## How to edit my signature?
How do I edit my signature. I have seen many people with colors, images, and background color in there signatures. What page has the ability for me to change my signature? JedOs 09:19, 4 December 2005 (UTC)
If you are logged in, at the top of the screen, click on my preferences. In the box that says Nickname, type in what you want your signature to be, then check the box below it that says raw signatures (don't use templates). Click save at the bottom of the screen, then follow the instructions that appear after the save button. Thelb4 09:26, 4 December 2005 (UTC)
Wikipedia:Signature#Customizing your signature.--Commander Keane 10:35, 4 December 2005 (UTC)
When I check the Raw Box and put this in[[User:JedOs | <FONT SIZE="2"><FONT COLOR="#000000">J</FONT><FONT COLOR="#1f3f00">e</FONT><FONT COLOR="#3f7f00">d</FONT><FONT COLOR="#5ebe00">O</FONT><FONT COLOR="#7cfc00">s</FONT> ]] [[File:Lily_the_white_poodle_(transparent_background).png|20px]]
It tells me that the HTML is invalid, how can i fix this? JedOs 11:31, 4 December 2005 (UTC)
See Wikipedia:How to fix your signature. Thelb4 12:05, 4 December 2005 (UTC)
You're missing the </FONT> for the initial <FONT SIZE="2">. -- Rick Block (talk) 17:28, 4 December 2005 (UTC)
Thanks, I decided just to delete, <FONT SIZE="2"> -- JedOs 19:31, 4 December 2005 (UTC)
## Changing the Font
Is there any way you can change the font style on Wikipedia?--XenoNeon 11:52, 4 December 2005 (UTC)
Other than standard stylings (strong, emphasis etc) most styling in Wikipedia is done by including HTML in wikitext. That is the <font> tag can be used to change font to Times New Roman. (I just typed <font face="Times New Roman">Times New Roman</font>.) You can also use <span> which gives a little more control with CSS. Read up on HTML if you don't know how to do this. Note that changing fonts in Wikipedia articles isn't recommended, as not everyone has fonts you may use, and it creates non-uniformity of article style. jnothman talk 13:41, 4 December 2005 (UTC)
Although of course you generally shouldn't be changing the font/colour... That's the job of the stylesheet. See: WP:MoS. Thanks/wangi 13:47, 4 December 2005 (UTC)
You should not normally try to change the font seen by other users. For one thing, you cannot presume that they have any particular fonts avaiable. A possible exception to this is to help people with browser with broken font support (e.g. IE) to see unusual characters, although two common cases of this are already covered:
• for International Phonetic Alphabet text, you can use the {{IPA}} template (/tɛmplət/);
• for mathematical symbols, you can use the maths feature, which offers readers various options for how difficult text is displayed.
• also there are the Polytonic template, for Ancient Greek with the full set of diacritics, and the Unicode template for a variety of other special characters from various languages.
If you want to change the fonts that you, personally, see, I believe you can overwrite all or part of the Wikipedia style sheet by creating a sub-page of your user page called monobook.css, but I haven't tried this.
Note that if you have one of the unusual cases where it is appropriate to force the font for all users, <font> elements have been deprecated for six or more years and styles can be placed on almost any element, so it is rarely necessary to use <span> as there will normally be a more appropriate element that can be used. --David Woolley 14:16, 4 December 2005 (UTC)
There is an instance where it is appropriate to use a different font: the internationally agreed convention on botanical names suggests that all botanical latin names should be shown in the italic version of the main font, but that all trade names or selling names of cultivars should be in a different style of font from the rest of the name. In other words, if the main text in which the name occurs is in a serif font, the trade designation should be in sans serif, and vice versa. Is there a styling tag which will automatically show the opposite style, without being as font-specific as the Times New Roman example above? SiGarb 18:26, 10 December 2005 (UTC)
## My edits are being erased!
Why are my edits erased without giving a reason? —Preceding unsigned comment added by 81.215.34.90 (talkcontribs) 2005-12-04 13:04:14
Looking at your contributions you have made only three edits (including this one), none of which are reverted. I'd recommend signing up for an account as it will allow all your edits to be listed together. Your edit to Azerbaijanis doesn't fit in with Wikipedia guidelines, and your talk page edit really is quite, eh, excitable! Assume good faith! I'd recommend working through the links in the message below. Thanks/wangi 13:15, 4 December 2005 (UTC)
Welcome!
Hello, and welcome to Wikipedia. Thank you for your contributions.
Currently, you are editing without a username. You can continue to do so as you are not required to log in to Wikipedia to read and write articles, however, logging in will result in a username being shown instead of your IP address (yours is Help desk/Archive 35). Logging in does not require any personal details. There are many other benefits for logging in to Wikipedia.
The Wikipedia Tutorial is a good place to start learning about Wikipedia. If you have any questions, ask me on my Talk page – I will answer your questions as far as I can! Thank you again for contributing to Wikipedia.
from Wikipedian: wangi 13:15, 4 December 2005 (UTC)
## Can someone please fix the search?
For the past week, it's been giveng me an error whenevr I try to search for anything. Can someone fix this?
• As the error message you recieved said, the server had a problem and would be back online soon. It now works, although I had nothing to do with this development. I suggest using the provided external search engine feature if it happens again. --WAvegetarian (talk) (email) (contribs) 22:21, 6 December 2005 (UTC)
## Standard translations of WP terminology
I am interested in doing some translation of project space pages (eg here, the Wikipedia: space) for the commons project, mainly. I believe that translators often tend to have lists of particular words (eg technical) that are always translated a certain way, so wherever you have "watchlist" in en: you have word/phrase "X" in language Foo. "Standard translations", if you will. Does anyone know if lists like these exist on wikimedia anywhere? I am not sure where to look or who to ask.
thanks, pfctdayelise 14:46, 4 December 2005 (UTC)
## choosing what articles will be featured articles
how does wikipedia choose what articles will be featured articles.
A good place to read would be Wikipedia:Featured article candidates. FireFox 15:01, 4 December 2005 (UTC)
## "Reverted edits by (X) to last version by (Y)"
Every time someone reverts an artivle, they seem to use exactly the same message, "Reverted edits by (X) to last version by (Y)" (complete with links).
It seems rather odd that nearly everyone should take the time to write out the formatting for this exact message (without ever changing a word or making a typo) every time they revert vandalism, so I though it must be an automatically generated message (it isn't). Is there some sort of shortcut people use for this (a template, maybe?) It just struck me as quite strange.
Admins have a feature called "roll back" that puts that text in. The rest of us usually just put "revert - (reason)" or "rvv" for Revert - Vandalism. Dismas|(talk) 16:37, 4 December 2005 (UTC)
Why only admins? It seems like a feature everyone could benefit from.
Because it's such a quick way of reverting people, it's only granted to users who have demonstrated that they are trustworthy, so others can't abuse it. Hermione1980 18:28, 4 December 2005 (UTC)
## Translation - Spanish into English
Spanish usage of the word romper and quebrar . Translate into English
This should have been posted at Wikipedia:Reference desk/Language. However, "romper" means "to break", "to shatter", or "to tear"; "quebrar" means "breaking", according to FreeTranslation.com, but I would hazard a guess that it really means "to break", as it's an infinitive. Hermione1980 17:53, 4 December 2005 (UTC)
Romper is more akin to "to rip/tear", and quebrar is more similar to "to shatter", but yeah, Hermione got it quite right. They are both infinitives, so they have to be conjugated. I'm a native speaker, so I should know ;). By the way, post questions like these on the Reference desk in the future, this page is to ask questions related to Wikipedia. Titoxd(?!? - did you read this?) 18:06, 5 December 2005 (UTC)
## Googling namespaces
What's the easiest way to search in specific Wikipedia namespaces with Google? ᓛᖁ 18:06, 4 December 2005 (UTC)
I use something like site:en.wikipedia.org/wiki/Wikipedia Foo beans , when I'm searching for Foo beans in the Wikipedia: namespace.--Commander Keane 18:59, 4 December 2005 (UTC)
How do I get those links in the Edit Summary poniting to parts of the article to appear (the ones that are arrows)? --LifeMega 19:39, 4 December 2005 (UTC)
When you edit a section of an article (using a mini "edit" button), the edit summary will automatically start something like /* Edit Summary links */ (That's for editing this question. I used the edit section button for this edit, and I found that in the edit summary). When I save this edit, there will be a little arrow in the edit summary.--Commander Keane 20:41, 4 December 2005 (UTC)
## Unblocking and autoblocker
I understand how to block specific IP addresses/usernames, but I don't have a clue how to unblock them. I'm sure it's something very stupid and simple I'm missing. I also don't understand the autoblocker. Could some more experienced, patient admin explain this to me? Hermione1980 21:10, 4 December 2005 (UTC)
Block can be undone through Special:Ipblocklist. There is also a workaround where you reblock the person for 1 second which will kill the previous block. The autoblocker blocks any IPs they have recently used if any account tries to edit through those ips.Geni 21:24, 4 December 2005 (UTC)
## Printing colors from List of Colors
User Manuel has sent the Help Desk an e-mail that I was unable to resolve for him. His original email read:
I am trying to copy and print several colors from your "Color List" so I can relate the names to their color. The names will print but the colors will not. Is there anything I can do to get the color to print ? Will appreciate your help
My initial response referring to the article didn't resolve his problems. He has sent me a followup e-mail.
Thank you for your e-mail. I may not have explained what I wanted to do correctly.
I get your LIST OF COLORS in my screen but when I try to print one color, any color, to relate the name of the color, as for example "Crimson red" to the color red square next to the name the "color" shown, does not print.
I have tried clicking on the Printable Version link shown on the left hand side of the screen and I have tried highlighting the wholo line and non of these will work.
Sorry if I am giving you too much of a problem.
I would be grateful for any assistance you could give him.
Capitalistroadster 22:56, 4 December 2005 (UTC)
The colours are implemented as background colours, which is semantically wrong, but, as HTML, is not a graphics language, difficult to avoid without playing tricks with CSS (which shouldn't be used for semantics).
I think all browsers default to not printing backgrounds as it wastes ink and toner and can make the printout difficult to read. Some do allow you to enable their printing, and that may be the easiest solution.
However, the introduction to the article states that the colours aren't gamma corrected, i.e. they are in a linear RGB colour space. As conforming web browsers and their printing software assume a gamma of about 2.2 (strictly an sRGB colour space, the colours will be wildly incorrect both as displayed and as printed. A better approach might be to screen grab and then use image manipulation software to adjust the gamma. Process limitations also mean that printed colours will be less accurate than those on CRT displays.
The best way of implementing this page so that it prints correctly is probably to use Unicode character U+2588, that is solid ink with no margins (██████ - a red bar), but that may well cause problems on platforms with poor font support, e.g. IE, especially on Windows 98 variants. A trick might be to use CSS to create margins that occupy the whole cell, but that's definitely an abuse of CSS, but maybe no more than abusing background colours. Neither of these solve the gamma problem. The template on the individual colour pages would need changing as well if teh Unicode technique proves safe.
--David Woolley 23:47, 4 December 2005 (UTC)
• Also, you can never really assume your printer will print the colors exactly as you see them on the screen. - Mgm|(talk) 05:55, 5 December 2005 (UTC)
I used to have a bookmark swiped from someone's user page which let me edit just the lead of an article. Now I've changed computers, lost my bookmark, and can't remember where I first got it. Help! Mark1 23:30, 4 December 2005 (UTC)
I don't know about a bookmark (it shouldn't be hard to write, but I don't know who has it), but you can install a user script to add it as a tab (marked "0") at the top of the page, kept at the user scripts project. There is also a second variant which puts an "[edit top]" link to the right of the article heading. Both are available from Wikipedia:WikiProject User scripts/Scripts. Ultimately, if you want to make it into a bookmarklet, all you need is a javascript that grabs the page title and transforms it into <http://en.wikipedia.org/w/index.php?title=MY_ARTICLE_TITLE&action=edit§ion=0>, to which it sends the browser. jnothman talk 23:51, 4 December 2005 (UTC)
Thanks; what exactly does one do with a user script? Mark1 02:12, 5 December 2005 (UTC)
The user scripts project (WP:US) does try to explain that, but doesn't do it very clearly, maybe. So if you are using the default skin for Wikipedia, what you need to do is edit your monobook.js file. There you can put some custom scripts which will get loaded by the browser on all Wikipedia pages. Then (as long as they don't need any additional helper functions) just paste in the code from either of the scripts mentioned above. Save, and you should have the appropriate tab/link available on the next article you load. jnothman talk 02:48, 5 December 2005 (UTC)
Thanks, that worked. ;) Mark1 13:07, 5 December 2005 (UTC)
# December 5
## Creating and Editing Templates
Hi After reading about 30 pages on templates, I still can't figure out how to create and edit templates like the one at the bottom of this question. By expimentation I have made some sucessful edits, but the whole template page looks like giberish to me and I can't find a page which explains it. Here is the link to the template page, thanks: Template:StargateTech Tobyk777 04:44, 5 December 2005 (UTC)
{{StargateTech}}
What you are calling gibberish is nothing to do with templates, but is how MediaWiki formats tables. See Help:Table for more info. You will need some understanding of HTML tables in general and of CSS to get the stargate template. jnothman talk 04:57, 5 December 2005 (UTC)
## IRC policy on Wikipedia
Recently, I've been logging #Wikipedia on IRC. According to one of the users on the channel (who is an experienced editor here on Wikipedia), if I were to quote any content from the IRC channel, this would be against the rules. I've reviewed Category:Wikipedia official policy, Category:Wikipedia guidelines and even Category:Wikipedia proposals and Category:Wikipedia rejected policies, but have found nothing stating this is against Wikipedia policy. I've also reviewed Wikipedia:Arbitration policy/Precedents attempting to find some guidance on this point but outside of ArbCom acknowledging lack of jurisdiction over IRC, I've found nothing to state that quoting IRC would be against policy. I've found several instances here on Wikipedia where IRC has been quoted. Could someone please point out where this is supposedly against the rules? Thanks, --Durin 17:59, 5 December 2005 (UTC)
As I understand it you could do so but it could not be used as evidence of anything.Geni 19:10, 5 December 2005 (UTC)
There is also some promise of no public logging of the channel on meta:IRC channels but I don't know if that applies. Against what rules specifically, anyway? Copyright rules, or arbitration/RFC rules? Where is this trying to apply exactly? jnothman talk 05:19, 6 December 2005 (UTC)
## "Preceding unsigned comment" message
Is there a template for the message "The preceding unsigned comment was contributed by User:SampleUser"? Or is it, like rollback, just a perk of being an admin? jfg284 you were saying? 18:35, 5 December 2005 (UTC)
There is a template, but you have to manually put in the details, such as the username and the timestamp.
Example: {{Unsigned|SampleUser|08:43, November 24 2005 (UTC)}} will produce: —Preceding unsigned comment added by SampleUser (talkcontribs) 08:43, November 24 2005 (UTC).
Akamad 19:24, 5 December 2005 (UTC)
If you are like me and aren't bothered with getting the date you would use {{unsigned|SampleUser|.}}.--Commander Keane 20:52, 5 December 2005 (UTC)
{{Unsigned|SampleUser|~~~~~)}} would also work. [[Sam Korn]] 21:01, 5 December 2005 (UTC) (edit: too few nowikis spoil the broth)
Actually, you can just use {{unsigned|SampleUser}}. I routinely use {{unsigned2}} though because you can copy and paste the user/time out of the history, insert a pipe (|) and be done with it. As an example from the history for this page, I copied "13:01, December 5, 2005 SampleUser", put a pipe between the time/user, "13:01, December 5, 2005|SampleUser" and put this in: {{unsigned2|13:01, December 5, 2005|SampleUser}}
to get this: —Preceding unsigned comment added by SampleUser (talkcontribs) 13:01, December 5, 2005
(Changed user name to SampleUser to protect the innocent). The only difference between {{unsigned}} and {{unsigned2}} is the second variation reverses the parameters (making it easier to copy/paste from the history view of an article). It also goes without saying that you can't omit the date/time from {{unsigned2}} because it's the first parameter. :P —Locke Cole 21:22, 5 December 2005 (UTC)
Thank you much. jfg284 you were saying? 23:15, 6 December 2005 (UTC)
## UserScript question
I want to use this script as a tab to get the title of the page and copy that to my clipboard (for easy pasting) or to maybe make the Location Bar equal the title so I can just highlight that and copy it. Is that possible? I'm not familiar with scripting...
Also, is there a script that will search the textarea when I'm editing? Firefox doesn't do it and I only see a replace script. I can't imagine it'd be that difficult, but what do I know. Thanks, I appreciate any help. Gflores Talk 18:37, 5 December 2005 (UTC)
With searching in text boxes, I think Opera 8.51 does it (but Opera 9TP1 doesn't, so I assume they'll fix that by the next full version). As to making a script, you may want to search general Firefox user scripting web sites. As regards to clipboards, access to them is going to be browser-dependent and the javascript varies. [6] indicates that there is an option to allow scripts Firefox to access the clipboard, but it doesn't indicate how to do te settign or reading. You may get more fruitful answers on a talk page at the user scripts project. Then again, you mayn't. jnothman talk 22:50, 5 December 2005 (UTC)
Thanks for the response. Firefox doesn't do it. Both Opera and IE do... I'll try searching again and hopefully I'll find something. Gflores Talk 05:16, 6 December 2005 (UTC)
## notification when a page is edited
Is it possible to receive an automatic alert when a page is edited? I could not find the answer to this question by searching and apologize if it is often asked. Josh
Not, as far as i know, the same way you're notfied with new messages. But, if you create an account, you can add pages to a "watchlist." Then, simply by checking your watchlist, you can see all the most recent changes to pages you've marked. jfg284 you were saying? 19:03, 5 December 2005 (UTC)
meta:Help:Related changes notes that email notifications are available in MediaWiki 1.5 with a particular extension. Seeing as the option is not available in prefs, I presume it's not installed here. If you really want changes in real time, I'm sure it would not be difficult to make a bot that checks on the Recent Changes IRC, or a little slower with the RSS feeds avaiable. Right now, though, I've lost where to find either of these. jnothman talk 05:51, 6 December 2005 (UTC)
## user e-mail
How does user e-mail work?
Registered users can go to Special:Emailuser/username and email from there if they have an address specified in preferences. [[Sam Korn]] 21:44, 5 December 2005 (UTC)
If you send an email using the Special:Emailuser, then your email address will be revealed to the recipient. If they choose to reply to you, then their email address will be revealed to you.--Commander Keane 22:26, 5 December 2005 (UTC)
## What happened to the ability to create new articles?
How come my ability to create new articles has all of a sudden been cut down today? --69.117.6.28 22:08, 5 December 2005 (UTC)
• Wikipedia is conducting an experiment on the effects of limiting new article creation to registered users. This may be temporary. You can easily register in order to bypass the restriction, or you can suggest that a registered user create the article for you. You can also discuss this experiment at the Village pump. Dystopos 22:30, 5 December 2005 (UTC)
• And do note, that once something has been created, you can edit it just like before. - 131.211.210.16 08:27, 6 December 2005 (UTC)
# December 6
How to get an image in the commons to appear on a wikipedia page? [[File:commons:Bball.gif]] doesn't work. [[Commons:File:Bball.gif]] doesn't work. I'm sorry I soiled your Help page with this question. Metarhyme 00:09, 6 December 2005 (UTC)
Unless I'm mistaken, you have to copy the image from commons, upload it here and then link it. Alf melmac 00:11, 6 December 2005 (UTC)
[[File:Bball.gif]] will suffice, if there is no file with that name at en.wikipedia.org, the software automatically tries to retrieve it from Commons. 130.243.135.145 00:30, 6 December 2005 (UTC)
Ie, DON'T reupload it here. That's precisely against the purpose of the commons. jnothman talk 02:00, 6 December 2005 (UTC)
Thanks, 130.243.135.145! [[File:Bball.gif]] works. Metarhyme 02:46, 6 December 2005 (UTC)
## Creating a Table
Where can I find out how to create a table or something like that to put stuff side by side or beneath each other? Str1977 01:42, 6 December 2005 (UTC)
Try Help:Tables, and let me know if you have any more specific questions. Another idea would be to look at an existing article that uses tables and copy the code. One that comes to mind is American Silver Eagle. HorsePunchKid 2005-12-06 01:44:45Z
## Is there a policy on slang and/or "vulgar" usages?
I added a couple of definitions to the disambiguation page for "spinner", one a computer-science definition, and the other a sexual definition.
I just checked it, and someone removed the sexual definition, commenting "deleted a vulgar/slang definition whose importance is sub-encyclopedic and whose mention essentially amounts to vandalism".
Now, that seems a rather extreme viewpoint to me, especially since my addition wasn't particularly graphic or gratuitous.
After reading up a bit on this site regarding policy, I couldn't find anything saying if there is a stated policy on such definitions, so I thought I'd ask you if there is such a guideline or policy. Are sexual definitions in disambiguation pages specifically discouraged, or was this just an instance of an easily-offended person?
Yours,
Tim Bessie -- Tbessie
If it follows Wikipedia:Content_disclaimer, then it is fine. x42bn6 Talk 01:25, 6 December 2005 (UTC)
Wikipedia is NOT censored for minors. Info on vulgar/sexual words is fine. -Greg Asche (talk) 03:20, 6 December 2005 (UTC)
I had a look at the page in question (spinner). While Greg and x42bn6 (what a name!) are correct, that Wikipedia is not censored for minors and that sexual content is not a problem, I'm not sure whether the definition you added is encyclopedic. Wikipedia is not a dictionary, and the primary purpose of disambiguation pages is to point users towards pages that otherwise might share a page name. I doubt that the sexual meaning of "spinner" is notable enough ever to have a Wikipedia entry, so it probably doesn't belong on the page. In other words, the editor who removed it did the right thing for the wrong reason.
I don't know enough about the GUI usage to know whether it's notable enough for inclusion or not, but you might want to look here to determine for yourself. —Josiah Rowe (talkcontribs) 06:05, 6 December 2005 (UTC)
• This is all correct. I would only caution that slang, and sexual or vulgar slang in particular, is hard to pin down in such a way that citations can easily be made. If there are verifiable, and preferably scholarly, accounts of the use of a term, that's great - but if it's just something all the 10th graders use, then it may not be very encyclopedic. Dystopos 06:02, 6 December 2005 (UTC)
Which is preferred (i.e., more server-friendly): [[The Republic|''Republic'']] or ''[[The Republic|Republic]]''? Or does it not matter? --zenohockey 03:12, 6 December 2005 (UTC)
I don't think there is a preferred version since either works just as well. Evil Monkey - Hello 04:23, 6 December 2005 (UTC)
Neither is more server friendly or changes functionality. But the user should not need to know that the pipe has been used. Since without the pipe, you don't have an option (ie "My article" is different to "My article") I think it would be preferable to have the quotes around the link. jnothman talk 04:41, 6 December 2005 (UTC)
• I don't think there's specific policy about it, but I prefer to have quotes and and other coding outside links, so links can be changed without affecting the quotes or code. - 131.211.210.16 08:40, 6 December 2005 (UTC)
There is one specific instance where you need formatting inside links - for ship names like the [[USS Enterprise|USS ''Enterprise'']]. Evil Monkey - Hello 20:20, 6 December 2005 (UTC)
## Is it okay to write articles on characters from television shows and movies?
Is it okay to write articles on characters from television shows and movies? I have never see one on Wikipedia, so I'm wondering if it's okay. For example:
The Parkers: Nikki Parker (Acted by Monqiue)
Mean Girls: Cady (Acted by Lindsay Lohan)
Moesha: Moesha (Acted by Brandy Norwood)
So is it okay? --anon
Yes, for examples see Darth Vader, Lisa Simpson, and George Costanza. Dismas|(talk) 05:31, 6 December 2005 (UTC)
There is a policy on articles on fiction and fictional characters. See WP:FICTION. jnothman talk 05:52, 6 December 2005 (UTC)
Okay! Thanks! --anon
## organisation structure of Microsoft
Please ask in more detail at the Reference Desk, not here. jnothman talk 13:52, 6 December 2005 (UTC)
## Date in templates?
I'm sure this must have been asked before, but since I can't find it I'll ask it here (again?): is there a way to add a timestamp (or rather, a date) to a template. I've been experimenting a lot with this, but all I can manage is either the day on which the template was created (when using subst:), or the current day (when not using subst:). But what I'm looking for is the date on which the template was used.
Thanks in advance, --IJzeren Jan In mij legge alle fogultjes een ij 10:05, 6 December 2005 (UTC)
To my knowledge, this data isn't stored and hence may not be used. jnothman talk 13:56, 6 December 2005 (UTC)
This is partly a trivial matter, and I've been meaning to ask this question for a while now, but why is it that wikilinks are always underlined when logged in, and only underline when "hovered" over when not logged in? For example, this link to Science is underlined always when logged in, but when not logged in, it simply appears blue and is only underlined when one "hovers" the mouse over it. Is there a technical reason for this, or does it have no purpose? -- Daverocks 10:18, 6 December 2005 (UTC)
They are only underlined on hover for me, which suggests that either you have selected a skin other than monobook, or you have provided your own monobook.css file to override the styling. --David Woolley 12:45, 6 December 2005 (UTC)
Check your preferences under "Misc.". Dismas|(talk) 14:06, 6 December 2005 (UTC)
Behaviour seems to vary, regardless of settings in prefs. I am set to always underline, but sometimes they are, some other times not. Another random WP glitch like the log out problem? --Cactus.man 14:10, 6 December 2005 (UTC)
The Google caches of WP pages are never underlined, at least in my experience. (I use Firefox, FWIW) --zenohockey 04:43, 7 December 2005 (UTC)
I forgot to mention before, I use Firefox. I don't have a monobook.css as a user subpage, and in my prefs it is set to always underline. My theory is that when one is not logged in, they don't have preferences set, and the default setting is only underline on hover. Thanks for the help though! -- Daverocks 09:49, 7 December 2005 (UTC)
## How do I contribute
HOW DO I CONTRIBUTE AN ARTICLE TO WIKIPEDIA? —Preceding unsigned comment added by 68.44.94.171 (talkcontribs)
See next question. --David Woolley 15:32, 6 December 2005 (UTC)
## editing article without an account
Why is it that I cannot create new articles without an account at this time? —Preceding unsigned comment added by 166.61.232.18 (talkcontribs)
Because too many anonymous users were creating silly articles, anonymous users must now request creation on Wikipedia:Articles for creation --David Woolley 15:29, 6 December 2005 (UTC)
You can also use Wikipedia:Requested articles, or find a sympathetic registered user who could start the article for you, or take a few seconds to register. Dystopos 01:58, 7 December 2005 (UTC)
## Question
Hello, I do not find where I can ask this question, so I do here: It seems, that the article about The Salvation Army is suddenly very very much shorter. Was this a vandal or was this a correct editing? There are no more external links and just one picture. Please have a look at it. I do not really know. thank you regards HAMUBA 6 December 2005
That was most likely vandalism since they simply removed images and half the article with no explanation -- I have reverted it. By the way, you can sign messages with your name and the date using ~~~~. Thanks for pointing that out. .:.Jareth.:. babelfish 16:00, 6 December 2005 (UTC)
Thank you for your answer - I had first to create an account also in English. The username from another language does not work... HAMUBA 16:21, 6 December 2005 (UTC)
## What is an atomic symbol AND how is it used? Give an example for a specific
(no question)
See the Reference desk this TYPE of question.--Commander Keane 20:51, 6 December 2005 (UTC)
## refering search subjects
I recently made an article entitled "The iBridge Network". However when I search for "ibridge" or "iBridge" I get no returns. I believe these two descriptors will be used the vast majority of the time when searching for this article. How do I go about making those two words return a result that either goes directly to the original article or reurn a link that goes there?
It's there -> The iBridge Network, I have redirects for those two terms. Alf melmac 21:16, 6 December 2005 (UTC)
The reason it wasnt turning up in the search is that the search engine only indexes every day or so. It will turn up in time. Wiki_Alf created redirects which will work for the two terms you mentioned immediately. -Lanoitarus 00:02, 7 December 2005 (UTC)
## "section=new" on URLs
I copied the "Ask a new question" code from Help Desk onto Wikipedia:Articles for creation. On Help Desk, the code creates a new *subsection* (===), while on Articles for creation, it creates a new *section* (==). Why is this? What would I have to change from the current Articles for Creation page to organize it by day? -- Creidieki 23:01, 6 December 2005 (UTC)
The HelpDesk one does just do a level 2 heading (==), not level 3 (===)... It seems when you say section and subsection, you're referring to the table of contents, but this just treats the highest level heading present as "sections" and thus "section" or "subsection" aren't defined by the number of =s in the headings, if you jusdge it from the TOC. Technically, == defines a section heading, but what is used to delineate days here on the HelpDesk is what could be termed a supersection heading, given by "= Heading text =". So that's what you have to do to delineate by date. jnothman talk 02:39, 7 December 2005 (UTC)
## Discussion Page
How do I make a new discussion page and archive the old one?--Anti-Anonymex2Come to my page! I've gone caliente loco! 23:39, 6 December 2005 (UTC)
Please see Wikipedia:How to archive a talk page. -- Rick Block (talk) 02:09, 7 December 2005 (UTC)
# December 7
Could someone help monitor this page? People are joining in the 'fun' due to the controversy with his father. Nil Einne 01:17, 7 December 2005 (UTC)
## I have a suggestion!
I have a suggestion about wikipedia, but I'm not sure who I should give it to.
Try WP:GC for "general complaints [or suggestions]"; if your suggestion regards the content of a specific article, post your suggestion on that article's talk page. --zenohockey 02:40, 7 December 2005 (UTC)
Ideas go into the Village pump, in particular, probably the proposals page. Just make sure first that it's not a perennial proposal (one that gets made all the time). jnothman talk 02:42, 7 December 2005 (UTC)
## essay on fantasy movie Gattaca
See Gattaca. -- Rick Block (talk) 02:56, 7 December 2005 (UTC)
## Picture issues - can't view in IMAGE, can't change size
I have uploaded my first image. I have 3 questions. 1) I am unable to see the image when I go to view it: http://en.wikipedia.org/wiki/File:Alter-auto-1.gif . Did I upload it wrong? It does show up on the Wiki page it is referenced on. http://en.wikipedia.org/wiki/Alter_%28automobile%29 2) I am unable to change the size of the image on the Wiki page it is referenced on, I have tried numerous "resizing" commands. I just get an empty box w/ the red X. 3) I was unsure of how to classify it with a COPYRIGHT TAG. I documented the web page that it was downloaded. It was a historical photo from approximately 1915. I received permission from the web site "owner" ---DRUSSEL3--Drussel3 03:24, 7 December 2005 (UTC)
(1) and (2) are the same problem. I have a feeling it is something to do with your file being a GIF. If you convert it to JPG or PNG, these should resize with no problem. I am not a copyright expert, but I'm not sure if an image of that age can hold a copyright. Possible templates include {{CopyrightedFreeUseProvided}}, {{Copyrighted}} or maybe others. jnothman talk 03:41, 7 December 2005 (UTC)
If you cannot identify the licence tag, you should at least include what the society's director wrote back to you and, if not implied by that, the question that you asked. Those form the licence, and it is important that they do not restrict use to Wikipedia. The site copyright notice says that licences must be given in writing to be valid. Note that the age of the photograph may be less than that of the car. I suspect it was taken in 1975. --David Woolley 19:39, 7 December 2005 (UTC)
The source site has captioned this image "Picture Circa 1969." --132.162.218.221 05:10, 8 December 2005 (UTC)
I obviously didn't do my research carefully enough! :-S jnothman talk 05:26, 8 December 2005 (UTC)
## Are the things put here free to use?
Are the things put here free to use? Because I wouldn't want to be vandalizing Wikipedia if I put it on another site. --anon
I'm not sure I understand your question—or want to—but in any case, there is no cost for reading or editing articles (though you must create an account to edit). Vandalism is forbidden, and there are a number of "mirror sites" that take Wikipedia articles—[answers.com], for example. --zenohockey 05:02, 7 December 2005 (UTC)
All Wikipedia content is licensed for public use under the terms of the GNU Free Documentation License. Basically this means you have to attribute it to "Wikipedia, The Free Encyclopedia", and license any derivative work under the same terms, including the full text of that license with the work. Dystopos 05:07, 7 December 2005 (UTC)
Oh, I see now...the perils of late-night editing... --zenohockey 05:10, 7 December 2005 (UTC)
Please read the GFDL. Attributing to Wikipedia is only sufficient when the copyright doesn't apply (fair use and pure citation without copying). Including the text of the GFDL is required for all non-fair use copies, as is including all the copyright owners (editors) and the document history. If you modify the content (e.g. by making an extract and including it in another document, and distribute in significant numbers, you must provide the revisable form of the document in a format for which it is reasonable to edit it with simple text editors and for which it is possible to get free rendering software (e.g. Microsoft Word is not an option). This is complicated because Wikipedia, itself, doesn't obey the letter of the GFDL (which is why my user page allows Wikipedia to re-license my contributions).
You need to read the GFDL, as even the above is only a selective summary. --David Woolley 10:38, 7 December 2005 (UTC)
I'm trying to say that there's another site (looks kind of like another encyclopedia) and I would like to put one of the articles on Wikipedia on that site. --anon
• You can do that Iff that site licenses its content under the GFDL and complies with all the conditions it imposes. A summary of those conditions is above. Thryduulf 20:52, 7 December 2005 (UTC)
## What does this pref do?
In "my preferences" there's a box that says "Enable 'jump to' accessibility links." What does this do? —Preceding unsigned comment added by Zzedar (talkcontribs)
The standard examples are people using text to speech ("screen readers") and Braille displays. They cannot easily scan for the start of the real text. As web designers like having navigation on every page, rather than separate navigation pages, a convention has arisen that, at the very beginning of the page, there should be a link to the main text. I believe this option suppresses those links (which are probably normally obfuscated by the styling). --David Woolley 10:42, 7 December 2005 (UTC)
## Image problem
I don't know much about about images, so... how would one go about fixing the syntax problem here? --zenohockey 05:13, 7 December 2005 (UTC)
• I fixed it for you. In templates like that you dont need the [[ ]]. JedOs 05:23, 7 December 2005 (UTC)
It seems someone corrected it, but the problem was not within the image markup, but with the definition of that template, which just requires the filename and size, but not the full link to the image. jnothman talk 05:29, 7 December 2005 (UTC)
Yeah, you added [[ ]] in thoughs type of templates the [[ ]] is automatically added. Since you put [[ ]] it some how rendred the image 2 times. But I fixed it for you. JedOs 05:36, 7 December 2005 (UTC)
## Userbox firefox
I used User mff enclosed with {{}} on my user page (it's still there) and it worked fine for awhile. Now the image is gone and REDIRECT Template:Userbox firefox remains. What happened? Halcatalyst 05:18, 7 December 2005 (UTC)
• Here use this {{userbox firefox}} JedOs 05:25, 7 December 2005 (UTC)
This was caused by a double redirect of Template:User mff to Template:User fox to Template:Userbox firefox. Fixed now. jnothman talk 05:32, 7 December 2005 (UTC)
## Adding 2 scripts to monobook.js
How do I add 2 or more scripts to monobook.js ?? JedOs 05:20, 7 December 2005 (UTC)
Well, you simply need to add the one script after the other... Importantly, everytime you change your monobook.js, you have to refresh your browser's cache which can be done most surely by visiting http://en.wikipedia.org/w/index.php?title=User:JedOs/monobook.js&action=raw&ctype=text/javascript&dontcountme=s and hitting your browser's refresh button. See the User Scripts project. Or maybe you need to be more specific with a problem you've had. You also might get better response on a talk page there. jnothman talk 05:36, 7 December 2005 (UTC)
Yeah I am current using Lupen's Filter Changes. But after I put the Live Preview script after it, neither work. I want to use this version of Live Preview, http://en.wikipedia.org/wiki/Wikipedia:Wikiproject_User_scripts/Scripts/livepreview.js JedOs 05:45, 7 December 2005 (UTC)
/* [[User:Pilaf/livepreview.js]] */
// [[User:Lupin/recent2.js]] - please include this line
document.write('<script type="text/javascript" src="'
+ 'http://en.wikipedia.org/w/index.php?title=User:Lupin/recent2.js'
+ '&action=raw&ctype=text/javascript&dontcountme=s"></script>');
This only activates the "recent2" functionality, and doesn't use LivePreview. You have to copy in the entire contents of User:Pilaf/monobook.js and not just the one line you have there. // at the beginning or, surrounding by /* and */ means that the text inside will be ignored and does nothing in javascript. jnothman talk 05:57, 7 December 2005 (UTC)
Yeah thats an artifact from the prior script, I left by accident, thanks for helping, by the way. JedOs 06:06, 7 December 2005 (UTC)
## Weird edits from possible bot
Can some one take a look at this history page. It's almost like a strange bot that copies a user. This thing/person has also set up an jgrutz (I'm jgritz) account which puzzles me even further. Can someone else take a look at this and comment Jgritz 09:27, 7 December 2005 (UTC)
I'm not sure i would quite consider this a BOT persay, he seems only to have done two edits ever and they were both differnt. However, since the link added had already been added anonymously severaly times (and removed by you), id say its clearly an deliberate imposter. It seems pretty clear that the user ought to be blocked and Template:Imposter applied, as he has no other contributions except more adds elsewhere, but an admin would have to do that.-Lanoitarus 09:39, 7 December 2005 (UTC)
## Claiming anon edits?
I seem to remember reading somewhere that you can lay claim to anonymous edits you've made if/when you register. Is this possible? If so, how do I do it? (By "claim", I mean so that the edit shows up as being done by your username, instead of just an IP.) Ends Of Invention 10:19, 7 December 2005 (UTC)
• Only developers can change edit attributions. There used to be a service where people could request having their edits reattributed, but it has stopped now. — JIP | Talk 10:49, 7 December 2005 (UTC)
But you can just link to your old IP's contribs from your user page... jnothman talk 11:09, 7 December 2005 (UTC)
How can I add an image to my article???
See Help:Images, but in general, upload the image (it must not be copyrighted, or can be taken with permission but this is not preferred) using the "Upload file" link on the left, and then insert in the page [[File:filename.jpg|options]] where options are appropriate as found on the Help:Images page. jnothman talk
As copyright exists by default in most things and in many countries cannot be abandoned (even in the USA, some people question the validity of abandoning to the public domain), it is normally best to have an image that is copyrighted but with a GFDL compatible licence. For modern images that are considered to be in the public domain, you should document this as though placing in the public domain were a licence grant, stating the original copyright holder and that they have placed the material in the public domain, and how you know that they did this. --David Woolley 18:16, 7 December 2005 (UTC)
## Unattributed image
An image from my website has been posted on the Wikipedia without attribution. I discovered it by accident. I wish proper attribution. I do not know how to contact the person who posted the image. What should I do: (1) insert proper attribution? (2) other? Thanks. —Preceding unsigned comment added by 160.79.32.242 (talkcontribs)
All images uploaded to Wikipedia require a free license so that they can be relicensed under Wikipedia's Gnu Free Documentation License. The person who uploads a copyrighted image is in violation of Wikipedia policy and copyright law. If you can provide clear evidence of a violation, you can go to Wikipedia:Request for immediate removal of copyright violation to request an immediate removal. Alternately, you can contact Jimmy Wales, Wikipedia's designated agent, directly about copyright infringements.
On the other hand, if you are happy to relicense your image under the terms of the GFDL, you can go to the image page and edit the page to indicate the correct attribution and license. Dystopos 16:27, 7 December 2005 (UTC)
If you do legitimise it, ideally, you should make the uploader aware they have transgressed. --David Woolley 18:30, 7 December 2005 (UTC)
## unsigned by...
What is the reason for adding to a question the "Unsigned by (ISP address)"
I thought it was pretty obvious. This way other users can see who added the question, and also have access to the user's talk page, where they can reply to him/her directly. — JIP | Talk 16:55, 7 December 2005 (UTC)
## Hubble Heritage
Does Wikipedia have permission to use images from the Hubble Heritage Project? ᓛᖁ 17:17, 7 December 2005 (UTC)
Interesting question. PD-NASA would be a first guess, but they're not - it's the STSI who operates it, and I'm not sure who they are legally... Shimgray | talk | 17:35, 7 December 2005 (UTC)
## CatAZ template
Hi, I am trying to use the above template but it doesn't seem to be working. I have gone to the webpage, "List of famous naturalized citizens of the United States" to find an example of how it is used, but this one is not working too. Can you please advise how it ought to be used? — PM Poon 18:41, 7 December 2005 (UTC)
Hi. The CatAZ template is only for Category pages, so that List incorrectly uses that template. If you would like to use a table of contents on an article page, use one of these here. I have now added toc6 template to it. There was also some formatting issues which I fixed. Gflores Talk 20:02, 7 December 2005 (UTC)
## Is there anything I can do to create a page without a username?
Is there anything I can do to create a page without a username? I don't really want another person to create it for me (cause I like doing it), and I don't really want a username. Is there some kind of place to discuss the matter? --anon
• Creating new pages has been switched off for anonymous users as a test to see if it can get rid of the masses of vandalism we get that way. Wikipedia:Articles for creation was set up so established users can start a page for anons. Once it is created you can let your creativity flow and add to it to your heart's content as long as you stay within Wikipedia regulations. However, if you really want to be the first one to start a page, you either have to wait for the test to finish (and hope it won't continue) or simply register a username. It has in fact got loads of benefits one of which is getting a username which makes you a lot more anonymous (your IP address won't be shared directly with everyone). Is there a specific reason you don't want to create an account? - Mgm|(talk) 20:40, 7 December 2005 (UTC)
I can't really understand why any frequent editor here wouldn't want to register a username; it's quick and easy, and doesn't involve any mandatory nosy questions (unlike the Yahoo registration process). You aren't required to use anything resembling your actual real-world name, or to reveal your e-mail address or any other personal information; you can pick something just as cryptic as your IP address (and less revealing) if you want. *Dan T.* 20:44, 7 December 2005 (UTC)
A recent, and apparently experimental policy change has been announced by Jimbo Wales, preventing anyone from creating a new page unless that person has a user name and is logged in. There has been debate at the village pump (for example in this thread) and elsewhere as to the value of this policy change, but for the moment it is being enforced. While it is you will have to either get a user name, or ask someone who has one to create any new pages you wish created. Wikipedia:Articles for creation has been created specifically to place such requests. I am curious, why don't you want to have a user ID, anyway? DES (talk) 20:48, 7 December 2005 (UTC)
Personally, I'm all for preventing anonymous IPs from creating articles. I'm also dubious about anonymous IPs editing Wikipedia at all. But that's as far as I'm going to go. Any non-blocked IP is, and should be, allowed to create an account, without having to reveal any personal information, even an e-mail address. There should probably be a CAPTCHA for creating an account but it should merely distinguish automated scripts from humans, not one kind of humans from another. — JIP | Talk 21:02, 7 December 2005 (UTC)
I don't think it's nice! Besides, I'm not sure if having a username is safe. If somebody hacked into my username, will they see any personal/important info? --anon
The only information they could get is what you typed. Look at the registration page and see what personal info you have to give. Even the e-mail address is optional. Notinasnaid 11:28, 11 December 2005 (UTC)
In fact, creating a User name is more anonymous, because if you don't use a User name, your IP address is displayed, and that can be traced to a particular provider, whereas only developers and certain admins (not all admins) can see the IP addresses of logged-in Users. Zoe (216.234.130.130 19:09, 13 December 2005 (UTC))
## IPA help
Is there a WikiProject or some other page where one can request help for IPA transcription?
A user has just added the pronounciation "Lay Mizz-rob" to Les Misérables (musical), which doesn't seem terribly accurate to me. I figured that the pronunciation ought to be in the IPA, per Wikipedia:Manual of style (pronunciation), but I don't know enough about either the IPA or French to do it properly. Where is the best place to ask for assistance on this? —Josiah Rowe (talkcontribs) 20:15, 7 December 2005 (UTC)
I'm sure the language reference desk would be more than happy to help in general. I personally pronounce this something like lɛ mɪzəʁab(l), but I don't know what's correct. jnothman talk 22:28, 7 December 2005 (UTC)
I've flagged it with {{cleanup-ipa}} which should get it the necessary attention. --David Woolley 22:37, 7 December 2005 (UTC)
Thanks, David and jnothman. —Josiah Rowe (talkcontribs) 22:42, 7 December 2005 (UTC)
## Reverting vandalism edit summary?
I've gotten into the habit of just typing "rvv" as the edit summary when I revert vandalism. However, I'd like to know how some people (very speedily, BTW, so they don't seem to be typing it out) get summaries like:
"(Reverted edits by [VANDAL] (talk) to last version by [LAST GOOD POSTER])"
Is there a set template to put in the summary box or something? Staxringold 22:32, 7 December 2005 (UTC)
• When you're an admin you get the rollback button which does that automagically. I think there is a "god mode lite" .js somewhere that helps for non-admins, but don't know where. Wikibofh 22:35, 7 December 2005 (UTC)
See WikiProject User scripts or Wikipedia:Tools for godmode-lite. Nonetheless, Staxringold, while the standard rollback notice identifies which version one is rolling back to, and also rolls back multiple vandalisations by one user, its consistency means a lack of detail. That is, we should really be using messages that say either "rvv" = "revert vandalism", or "rv test" = "revert something that wasn't quite vandalism", or "rv blanking" which could just be "rvv", or "rv " with some other reason, such as "added duplicate content", or "copyvio", etc... jnothman talk 22:45, 7 December 2005 (UTC)
Also be very careful not use that type of rv explanation for other content disputes. I use the rollback button a lot but only for indisputable vandalism for pages in which I have a content interest; for those pages which I do not actively edit or engage in discussion I will use the rollback for obvious nonsense (a slightly broader category). Every other kind of reversion deserves an explanation in either edit summary or talk page. alteripse 13:02, 8 December 2005 (UTC)
Does there remain any means of changing my account password? Where this option would ordanarily be on the log in page, it is gone. Could you help?--Thomas Aquinas 23:25, 7 December 2005 (UTC)
Go to "my preferences" at the top of any page, just to the left of "my watchlist". AnnH (talk) 23:28, 7 December 2005 (UTC)
# December 8
## Category and foreign article
Is it possible to link a foreign article into a English category? How? WriterFromAfar755 00:38, 8 December 2005 (UTC)
Do you mean to add an article in another language Wikipedia into a category in English Wikipedia? No, this is not possible: Why would you want to do it? English Wikipedia should rather have an article on that topic than add a non-English-language article to the English encyclopaedia's category. jnothman talk 01:58, 8 December 2005 (UTC)
A good solution to the problem–assuming that jnothman's reading of it is correct...?–is to create a new stub article on the English wikipedia, and then to put the English article into the appropriate category. The English article can then be linked using an interlanguage link to the articles in other languages. (For bonus points, add a note to the talk page of our article that there is extensive information in the foreign article waiting for translation.) TenOfAllTrades(talk) 15:08, 8 December 2005 (UTC)
## discussion
Please answer me quickly, im a new user. how do i add to discussion? --Chormang 02:07, 8 December 2005 (UTC)
Click on "Discussion" at the top of the screen, right next to "Edit this page", which will take you to the talk page of the article you want to discuss, and once there, click on "Edit this page" and say what you want to say. Titoxd(?!? - did you read this?) 02:32, 8 December 2005 (UTC)
Discussion happens on the "talk page" of an article, which you reach by clicking "discussion" up the top. You can either add to a discussion that is already taking place, or start a new topic of discussion. To start a new topic on the discussion page, click the "+" button up the top; type the subject and the content, save and you're done. To reply to a current discussion, go to the appropriate section of the page and click the link. Indent your comment with colons (:) [although some people use asterisks (*)], make an edit summaryy and save. Don't forget to sign! I hope that helps. jnothman talk 02:35, 8 December 2005 (UTC)
## Fairuse on screenshots
Do we really need a fairuse rationale for screenshots? - Ta bu shi da yu 02:30, 8 December 2005 (UTC)
Yes. See Wikipedia:Screenshots, maybe. jnothman talk 02:37, 8 December 2005 (UTC)
## Wikipedia on PDA
Joe sent the following question to the Wikimedia Help Mailing List.
Hello, i am a software developer, and i am involved in a project concerning your wiki software. My partners and i have a few questions on how to use your software. it basically involves putting your wiki software onto a PDA handheld device. i downloaded the source to the software but we dont know what to do with it from there. if you could help me out on how to put and access your wikipedia software on other devices. if you need anymore info please let me know.
I would be grateful for any assitance you can give him. Capitalistroadster 04:36, 8 December 2005 (UTC)
Erik Zachte has already ported to PDA: http://members.chello.nl/epzachte/Wikipedia/ --Commander Keane 15:29, 8 December 2005 (UTC)
## Language symbols
In some articles (but I can't remember which) I noticed a symbol before an external link signalling that it's in French or Spanish etc. Where do I find those? David Sneek 12:02, 8 December 2005 (UTC)
• Can you point us to such an article? - Mgm|(talk) 13:08, 8 December 2005 (UTC)
The use of symbols instead of naming the language is highly controversial. See Wikipedia talk:External links#Foreign-language external links. Susvolans 13:09, 8 December 2005 (UTC)
Mgm - No, it's something I encountered a few times, but forgot to bookmark and only later I realized that they might be useful for some of the pages I keep an eye on.
Susvolans - thanks for that link. Now I'm not sure if I will use the symbols, but at least I know how to put them in there. ({{es icon}}=(Spanish), {{nl icon}}=(Dutch), {{fr icon}}=(French), etc.)
David Sneek 15:27, 8 December 2005 (UTC)
## User's own talk page bolded in Recent changes
Why is the link to my own talk page suddenly bolded in Recent changes? — JIP | Talk 12:48, 8 December 2005 (UTC)
Have you put it on your watchlist? Susvolans 13:11, 8 December 2005 (UTC)
Must have. For me only watchlisted stuff is showing bold. - 131.211.210.16 13:56, 8 December 2005 (UTC)
I had my user page on my watch list but not my user talk page. But I don't rememeber ever putting anything in my watch list. — JIP | Talk 14:00, 8 December 2005 (UTC)
When you watch a page, you automatically watch the associated talk page, and vice versa - as a result, your watchlist can sometimes show pages that were never created. Shimgray | talk | 14:24, 8 December 2005 (UTC)
(after edit conflict) You cannot watch talk pages independently of article/project/user/etc pages and vice versa. If you have your user page on your watchlist you also have your user talk page on your watchlist; if you add Wikipedia talk:Help desk to your watchlist, you get Wikipedia:Help desk as well. See Mediazilla:1862 for a request to be able to filter your watchlist by namespace. Thryduulf 14:25, 8 December 2005 (UTC)
Yes, but how did my user page get on my watch list without me putting it there? — JIP | Talk 14:26, 8 December 2005 (UTC)
Quite easy to do it by accident, if you're editing without paying much attention - you accidentally tick the box saying "Watch this page" when going to save or preview. I quite often accidentally tick the minor-edit box... Shimgray | talk | 14:29, 8 December 2005 (UTC)
## Custom reference numbering
I've been doing an extensive makeover on Hopkins School (I've been doing mostly cosmetic work until the school archivist gets back to me so I can improve the short history section). You'll notice there is a reference in the sidebar for the Endowment, auto-numbered 1 (because the side-bar is the first code for the article) and a note over financial aid, auto-numbered 2. The problem is when READING the article the endowment is the second thing you see, not the first. I was wondering if there was something one can add to the ref code to custom number (or do I just have to shift the references around to match the auto-numbering, even if it isn't perfect)? Staxringold 14:01, 8 December 2005 (UTC)
Yes, there is a way of using multiple references to the same footnote that should be adaptable to what you want to do. See Wikipedia:Footnotes#Example with multiple references to the same footnote for the templates in question. Thryduulf 14:20, 8 December 2005 (UTC)
Is there a link to a list of all the classification templates for users?, If you don't know what I mean ....
en This user is a native speaker of English.
fox This user contributes using Firefox.
gb-0 This user cannot tolerate any form of Gibberish language, and is therefore easily emotionally traumatized by The Sims.
1337-0 This user has no idea what 1337 is and/or prefers to contribute using proper words.
175 I scored a 175 on the Are You a Wikipediholic Test.
xp This user uses Windows XP.
win This user contributes using Microsoft Windows.
This user opposes the installation of any kind of advertisements on Wikimedia Foundation operated sites.
I mean that sort of thing.They are a great idea - well done to whoever thought of it - but I would like to see them all. . To anyone who replies - thank you. DTR 17:03, 8 December 2005 (UTC)
I have tried looking myself, but as of yet have found nothing. The best I can find is just a search [7] of templates with the word "user" in the title. It's not ideal. FireFox 18:00, 8 December 2005 (UTC)
Templates starting with "user" can be found from Special:Allpages, here. The language ones categorize users in subcategories of Category:User languages. The others almost certainly end up categorizing in some subcategory of Category:Wikipedians. -- Rick Block (talk) 19:36, 8 December 2005 (UTC)
While the language ones are at Wikipedia:Babel, a fair collection of others are available from Wikipedia:Userboxes. Tis list is nonetheless incomplete. jnothman talk 21:47, 8 December 2005 (UTC)
There are also many that haven't been made into templates and exist soley on user pages. You can make your own using the following:
{{userbox|icon background color|text background color|userbox icon|text of userbox}}
--WAvegetarian (talk) (email) (contribs) 03:12, 9 December 2005 (UTC)
• I just dug up some of those boxes for my own userpage by going through the "what links here" for Template:Userbox. Worked like a charm. - 131.211.210.16 08:35, 9 December 2005 (UTC)
## Pronunciation
How do you pronounce the words Wikipedia? Thanks,--166.66.60.42 17:40, 8 December 2005 (UTC) Tipper
See Wikipedia. TenOfAllTrades(talk) 17:55, 8 December 2005 (UTC)
## Diagram on Bremelanotide (formerly PT-141)
Hi!
I was trying to fix the Chemical structure structure diagram on the Bremelanotide article, but I couldn't figure out what was wrong. Can anyone help?
Thanks, Rasmus (talk) 18:50, 8 December 2005 (UTC).
Code has been added to the image server to stop it from trying to thumbnail very large images - doing so was causing an undue burden on it, and posed a ripe avenue for denial-of-service attacks. I suggest you reupload at around 1000 pixels wide, and it'll thumbnail fine. -- Finlay McWalter | Talk 18:54, 8 December 2005 (UTC)
## Table is displayed at the bottom of the article
I made a table for fuel oil, but it is always displayed at the bottom of the article, even though there is text beneath it in the source. Thanks, Kjkolb 22:49, 8 December 2005 (UTC)
I'm guessing that is HTML, and I have no idea what was wrong with that. I have replaced it with wiki table syntax, although I changed the style a little - you may want to take a look at Wikipedia:Table to modify it. Or just ask here.--Commander Keane 23:32, 8 December 2005 (UTC)
Thanks! -- Kjkolb 01:43, 9 December 2005 (UTC)
# December 9
## Use someone's real name or their pseudonym?
I looked in the WP:MOS but I couldn't find any guidance about this. If a person has one or more pseudonyms/pen names etc, which one should be used? Which one should even be the article name?
I have a couple of feelings about this. 1. The usage should be consistent throughout the article, otherwise reading it may make it seem schizeophrenic. 2. It would probably make sense for the name used to be the same as the article name. Obviously you'd have RDRs from all the other names.
Some examples...
1. I realised this was a problem when editing William Wharton (author).
2. Lewis Carroll mostly uses Dodgson, but inconsistent. Someone said to me on the Talk page that there are times when it is appropriate to use both (eg in the context of book commentary, use Carroll, elsewhere use Dodgson).
3. Sean Combs consistently uses Combs.
4. Elton John doesn't even mention his real name until the first section (although he changed his name by deed poll, so fair enough).
5. John Wayne real name not mentioned until first section, then used for precisely two pars before switching back to Wayne, with no reason given.
sigh. a little help? --pfctdayelise 00:02, 9 December 2005 (UTC)
It depends on how and when the pseudonym was or is used, I think. Charles Lutwidge Dodgson is a good example. He published his books as Lewis Carroll, while in all other contexts he was Dodgson. It therefore makes some sense to write that "Dodgson took up the new art form of photography" and "Carroll wrote poetry". But with so many contributors it's hard to get consistency and I notice the article also suggests "that Carroll used the fungus ergot", which should probably be changed to Dodgson... In the John Wayne article the final reference to "Morrison" seems reasonable, because that paragraph juxtaposes the icon Wayne with the real person behind the myth. David Sneek 07:35, 9 December 2005 (UTC)
## Changing Color/Font of Signature?
Hi. I've noticed various users, when signing their names, use purple backgrounds and yellow text, or brown backgrounds and purple text, or some strange combination of the like. Is there a way to edit what happens when you sign with 4 tildes (~), or are they manually editing each instance?--Canaen 02:34, 9 December 2005 (UTC)
You essentially can use HTML formatting in your signature as set on your preferences page. See Wikipedia:Signature#Customizing your signature. jnothman talk 03:00, 9 December 2005 (UTC)
<td bgcolor="#008000"><font color="#ffffff">[[User:Canaen|Canaen]]</font></td>
I enter this into thje nickname area, and my name ends up jumping down a line, after the timestamp. Any way I can fix this? 10:48, 9 December 2005 (UTC)
Don't use <td>. <span> might be better. — JIP | Talk 11:01, 9 December 2005 (UTC)
Using <span> gives me this: Canaen 22:01, 9 December 2005 (UTC) The text is white, as I wish, but the background is no longer Green.
This issue has been resolved. I thank you all. Canaen 23:27, 9 December 2005 (UTC)
## Font
Please, what font does Wikipedia use?-Gillean666 03:44, 9 December 2005 (UTC)
Please, ask more specific questions. This depends on where you look and what skin you use; for the default skin it uses your browser's default sans-serif font:
body {
font: x-small sans-serif;
...
}
— Sverdrup 14:10, 9 December 2005 (UTC)
## Award!
when do i get an award, reward or star.
Because i have actually being contributing mostly every day, and stopping fools from vandalism,(reversing)
>x<ino 10:35, 9 December 2005 (UTC)
Usually, when someone notices your work on their own, and gives you one.
• It also helps to give people awards yourself. Giving yourself often leads to people appreciating you and giving something in return. - Mgm|(talk) 10:57, 9 December 2005 (UTC)
":Usually, when someone notices your work on their own, and gives you one." What!? I though, when creating article, it isn't yours nor you shouldn't clame it.
Anyway How do i award myself?.
like i said, I either want to be an admin or award.
I am not pushing my luck..but come on:P
>x<ino 11:11, 9 December 2005 (UTC)
If you want to be an admin, you can nominate yourself on WP:RFA. I don't particularly think anyone is going to give you an award merely for asking for one. As for MacGyverMagic's comment, it's true that no one owns articles, but Wikipedia still keeps track of which editor has contributed what, and people can see what you have added to articles. — JIP | Talk 11:27, 9 December 2005 (UTC)
And what do you mean, they won't give me one, because i asked!?
If i don't ask, they won't notice, "it's good to give it a try!" "MacGyverMagic's comment" you mean mine:)
I know you can see the contribution, you mean the person that first edited an article, is like the owner(not owner but he started it)
>x<ino 11:43, 9 December 2005 (UTC)
Sorry, I misread the indentation and thought MacGyverMagic's signature applied to both comments. Notice I didn't say "for asking for one", I said "merely for asking for one". Asking for awards doesn't hurt, but if all you do is ask "can I have an award, please?" without showing what contributions you have made, it won't probably work. Also, aren't awards supposed to be additional gifts given solely as an expression of goodwill? It's not like they're some sort of wages that people are legally entitled to. — JIP | Talk 12:38, 9 December 2005 (UTC)
maybe MacGyverMagic maybe a fool:P
First, i ask for an award, because i deserve it! I don't need to list my contribution, because i already listed them at my UserPage [8]
Gift!? is it because of the "Leave a Complaint, SITE, CONTRIBUTION/GIFT" is it because of that
First of all, if i get payed for contributing, i won't bother putting it there, second, voluterring is also a gift, a free gift to give, without asking for money. I wasnt asking for money from wiki >x<ino 12:46, 9 December 2005 (UTC)
## WIKI CREATOR
Who is the fool:P that owns/created/form this wikipedia!?
>x<ino 12:48, 9 December 2005 (UTC)
## Prevent anons from creating talk pages for nonexistent articles
Today I've seen a couple of talk pages created for nonexistent templates, created by anon users, which have turned out as vandalism. I seem to remember that although anons can't create articles any more, they can create talk pages. I suggest that anons should be prohibited from creating talk pages for articles, categories, templates or project pages that don't exist yet, to prevent this sort of vandalism. — JIP | Talk 12:58, 9 December 2005 (UTC)
• Shouldn't this be at the village pump proposal page?- Mgm|(talk) 13:57, 9 December 2005 (UTC)
I've copied this to wikien-l, to see if anyone can forsee problems. I'd advise bringing it up on appropriate Village Pump pages, though - you'll get more useful feedback there. Shimgray | talk | 17:26, 9 December 2005 (UTC)
I'm already on record as opposing the prevention of anons creating pages, but I really oppose not letting them create Talk pages. How are they supposed to discuss changes they made to the articles they're allowed to edit? Zoe (216.234.130.130 19:14, 13 December 2005 (UTC))
i've has , and my ipod for about a 2 weeks and now it's saying o.k to disconnect. what does that mean?
## Convert images from svg
Please could someone convert File:Soccerball.svg from svg to png, jpg or psd so I can't edit it using Adobe Photoshop? Thank you. CG 17:31, 9 December 2005 (UTC)
Mediawiki already did that before it sent it to your browser: just hit save-as. But why would you want to edit it with photoshop, as opposed to a free SVG editor like Inkscape? -- Finlay McWalter | Talk 17:48, 9 December 2005 (UTC)
In general, you should not convert vector graphics to raster formats for editing. This image is public domain, but, if it had been GFDL, you would be violating the spirit of the GFDL by making the image more "opaque" than the original. --David Woolley 10:36, 10 December 2005 (UTC)
## Re-naming a category
Hi, It has become apparent that a couple of categories I have created have been improperly named. Specifically, these are "Category:Pederastic relationships" and "Category:Mythical pederastic relationships". Since the included articles are not about relationships but about persons, I'd like to request that they be re-named "Category:Pederastic lovers" and "Category:Mythical pederastic personages". Thanks in advance Haiduc 18:00, 9 December 2005 (UTC)
Renaming a category can be quite a long process depending on how many articles there are. Since these two categories have only a couple of articles, all you have to do is change each article so instead of [[Category:Pederastic relationships]], they would say [[Category:Pederastic lovers]]. To stop the new categories from being a red link, you would create them the same way you created the first set. Thelb4 19:12, 9 December 2005 (UTC)
Also, you would then take the original categories to Categories for Deletion. Thelb4 19:14, 9 December 2005 (UTC)
It might be better form to nominate for CfD before depopulating it, and indicate in your nomination what should be done with the articles (ie moved to your preferred category). I have a feeling this is better Wikiquette, but I can't find the guideline anywhere on CfD, so I dunno. pfctdayelise 22:49, 9 December 2005 (UTC)
On WP:CFD, under "How to use this page", it's the second bullet of part II, step 5. -- Rick Block (talk) 17:30, 10 December 2005 (UTC)
## Userboxes along side of page
Can anyone help turn the series of userboxes on my page into a long line along the right side, alongside the remainder of the page's text, a la User:Cmdrjameson? Thanks! - Wezzo 20:59, 9 December 2005 (UTC)
## Category:Role-playing games weirdness
The Category:Role-playing games page has several problems that I can't figure out. First, some entries (such as Engel and RhyDin) seem to be listed under "*" and not under their first letter. Second, the page seems to end at "R", when I know at least Worlds of Wonder should be listed. Thanks to anyone who can explain or help. --GRuban 22:06, 9 December 2005 (UTC)
I came across this same problem at commons. It's very annoying. It happens when categories become huge. The reason RhyDin (which needs some serious wikification, btw) is listed under "*" is because on its page it has [[Category:Role-playing games|*]]. To me, this is kinda cheating, to force it to the front of the listing. This kind of syntax is useful for pages like List of movies featuring roleplaying. You would want this to list under M for movies, not L for list. So on its page, it should have [[Category:Role-playing games|Movies featuring roleplaying, list of]] (or just "movies", which AFAICT would do a good enough job). This feature is especially useful when you want to have people list under their last names rather than their first, which is what happens by default.
What I tried to do to fix it, was to go to each page and change it to [[Category:Foo| ]] so it was sorted by space. But then it collapsed again a couple of days later.
Basically, it's a bug. I don't know enough about bugzilla to point you to a link for it, but I'm sure there are plenty.
de:User:Kolossos has created a tool to show you a category tree on commons. You could ask him nicely to implement a similar tool for en. :) pfctdayelise 22:59, 9 December 2005 (UTC)
also, to see further listings, click on "next 200". There is World of Darkness, but I don't see Worlds of Wonder.pfctdayelise 23:03, 9 December 2005 (UTC)
I've fixed the category links on RhyDin and Engel (game) to remove the blatant advertising. — JIP | Talk 17:15, 10 December 2005 (UTC)
Thank you all, folks. I didn't see the "next 200" link, but findings it, yes, Worlds of Wonder is there. Thanks for fixing those two hacks, JIP. I think this means we need to split this category page somehow, since it's too large if people are resorting to hacks to make names findable. Will mull over. GRuban 21:45, 12 December 2005 (UTC)
## Babel
What is a "babel"?--Anti-Anonymex2Come to my page! I've gone caliente loco! 23:49, 9 December 2005 (UTC)
Babel means "confusion" in Hebrew. It is in the name of the Tower of Babel, which is where G-d confounded the language of mankind. In Wikipedia, Wikipedia:Babel refers to a set of templates which display the level of proficiency a user has in various langages. Izehar (talk) 23:52, 9 December 2005 (UTC)
Wikipedia is not censored for minors. It's safe to say God here. — JIP | Talk 07:23, 10 December 2005 (UTC)
• Especially when you refer to the deity with no additional bad meanings or swearing. - Mgm|(talk) 12:21, 10 December 2005 (UTC)
Yes, but it is actually contrary to the religious beliefs of some people to speak or write the name of God: hence G-d. Palmiro | Talk 16:53, 10 December 2005 (UTC)
This is something I've never understood. "God" is an English word. It's not something God chose a name for himself. If we're so afraid of incurring God's wrath by speaking his name in vain, why don't we start writing "d-ity", "c-eator", "m-ker", "L-rd", "o-nipotent b-ing", "i-telligent d-signer" and so on as well? — JIP | Talk 17:08, 10 December 2005 (UTC)
Don't ask me why, I'm an atheist! As far as I know, it has to do with the idea in Judaism that the original name of God is sacred; some Jews carry this over into other languages as well by writing D-o, G-d etc., considering those words to represent the name of God (unlike descriptive terms such as deity) while others, I think, consider that only the original Hebrew name must not be uttered. I'm sure someone else (possibly Izehar) could give you a more accurate and complete account of it. Palmiro | Talk 18:00, 10 December 2005 (UTC)
# December 10
## Installing Bots
Is there I can install a bot on my own wiki? I have no knowledge of programming (other than PHP, HTML and such) - would it be possible to install some kind of simple bot to delete things and check things or whatever? Thank you kindly for any help you could offer!
I was hoping for some simple instructions for the complete newbie )-: but that helped a little; just cant like find onw I can download and install then tear apart to learn to build my own... -- 24.237.6.216 19:15, 13 December 2005 (UTC)
## Siblings on Wikipedia
Is there a known amount of Wikipedians with siblings who are also Wikipedians? --Ali K 01:34, 10 December 2005 (UTC)
• This is not really the right place for factual questions, even if they regard WP. Wikipedia:Reference Desk Would be more appropriate. That said, however, I sincerely doubt this statistic exists, because of the tons of anonymous users and the fact that registration doesn't require anything more than a user name and email address. -Lanoitarus 03:36, 10 December 2005 (UTC)
• I was a bit sceptical about placing my question here, maybe someone should mention that at the top of the page? Thanks for your help.--Ali K 05:23, 10 December 2005 (UTC)
• Good idea. (See top of page). Dystopos 05:56, 10 December 2005 (UTC)
## Men vs Women
Does anyone know the ratio of men to women users of Wikipedia--Ali K 01:35, 10 December 2005 (UTC)
• This is not really the right place for factual questions, even if they regard WP. Wikipedia:Reference Desk Would be more appropriate. That said, however, I sincerely doubt this statistic exists, because of the tons of anonymous users and the fact that registration doesn't require anything more than a user name and email address. -Lanoitarus 03:36, 10 December 2005 (UTC)
• The intro says: Here you can ask questions about Wikipedia and get help editing articles.. I don't see why asking factual questions about Wikipedia shouldn't be placed here. The intro clearly allows it. - Mgm|(talk) 12:24, 10 December 2005 (UTC)
• Thankyou, someone who sees my point!--Ali K 14:07, 12 December 2005 (UTC)
• But nobody who gives an answer... -- 66.58.233.23 02:47, 13 December 2005 (UTC)
• How could one possibly give an answer that doesn't exist? There's no data to base it on. -- Mwanner | Talk 02:59, 13 December 2005 (UTC)
## Are Articles Listing (or Describing and Linking to) Important National Dates Appropriate For Wikipedia?
Is it an appropriate subject for a Wikipedia article, or for a category, to write about dates of national importance? Not all such dates are included in (for one example) List of holidays by country. Or in any other list or category I've seen here. Yet, it seems to me just as important a way of understanding a nation, to describe the dates (and the reasons why those dates matter) which resonate in the memory and culture of a country -- as it is to describe the geology or the population or the GDP of a country.
Please comment, I'd welcome direction on this. Cheers, Madmagic 03:52, 10 December 2005 (UTC)
• Yes, dates of national importance can be quickly covered in a one-line description in the date article like July 31 (Independance Day in the US IIRC) or December 5 (Sinterklaas in the Netherlands). If you want to describe the holiday or event itself in more detail, a separate article named after the event (instead of the date) is probably appropriate. Do you have anything specific in mind? - Mgm|(talk) 12:30, 10 December 2005 (UTC)
Hi Mgm, thank you for the response. Re-reading my question this morning I can see I wasn't clear. :) I'll try giving an example of what I mean.
Imaginary article (or category) title: Important Dates In British History. Article/category includes a January-December list of dates, with links to the articles on the Gunpowder Plot, the signing of the Magna Carta, Norman Invasion of 1066, etc. Cheers, Madmagic 15:12, 10 December 2005 (UTC)
## I can't edit long articles/sections anymore!
Sometime within the last 24 hours, I've lost the ability to submit changes to moderately long articles and sections of articles. User:Melchoir#Test_1 seems to be about the limit; if I add a few more characters and click "Save page", it times out; after a few minutes a Wikipedia Error message shows up. The same happens if I click "Show preview". If I then remove the offending characters, going back under the limit, I can submit and preview with almost no lag at all. This happens whether or not I'm logged in, in both Safari and Firefox, and I've tried two static IPs in the same building.
On the other hand, I'm able to post extremely long sections of text to forumer.com, as in here, and I can post to Wikipedia as normal if I go through a remote proxy, such as at Anonymouse.org.
What's going on? Melchoir 05:01, 10 December 2005 (UTC)
I just checked, and I have the same problem on the other languages, as well as Wikisource... Melchoir 07:22, 10 December 2005 (UTC)
I have this problem in the office, e.g. I can't resubmit this page after an edit conflict. My guess is that it is due to the web proxy that is used, in this case a Microsoft one. Note that many ISPs don't let you not use one. In most cases it is better to use sectiion edits --David Woolley 10:17, 10 December 2005 (UTC)
## how to create special pages
i am starting my own wiki (http://wikiclassifieds.org) and would like some directions on how to create custom special pages. thanks. -- Zondor 05:25, 10 December 2005 (UTC)
## Time in Time Stamps - How to edit?
I've noticed the time in timestamps is all UTC. Is it possible to change mine to read my own time zone, or is there something I don't know about Wikipedia which means they all have to be "UTC or bust"? Gohst 15:22, 10 December 2005 (UTC)
Click on the "my preferences" up on the top right hand corner, then go to "date and time". Click "fill in from browser". pfctdayelise 15:25, 10 December 2005 (UTC)
## How do I attribute anonymous edits with my IP to my username?
How do I attribute anonymous edits with my IP to my username? I remember reading somewhere that you could do this however I can't seem to find instructions. I'm not sure if this is no longer possible or what. :/ I've been editing for a while anonymously so it would be great if I can indeed add all my anonymous edits to my username without actually having to publically reveal my IP (e.g. making a big message on my user page saying "xx.xx.xxx.xx was me editing anonymously, here are my contributions".. I really would prefer not to have to do that -_-
Thanks for anyone that can help!
Wikipedia is cool :D
--Red-skinned femme-fatale black-latex-clad b-tch from Hell 16:45, 10 December 2005 (UTC)
1) If you are the sole user of that IP, you don't need to make a mess and list those edits on your userpage, you can refer people to the contribution history for that IP. 2) If you are not the only user of that IP, changing the attribution for those edits wouldn't have been possible anyway. Are you unhappy with revealing your IP, or with listing all your anon contributions on your userpage? - Mgm|(talk) 19:19, 10 December 2005 (UTC)
## Possible Licence Mixup
Führerbunker
This is not a copyright violation, but I would like to know whether the licence on a picture is ok as it is: The picture included (and others linked from Führerbunker) includes a text which forbids commercial use, as does the text on the picture's page. Is this an acceptable licence for Wikipedia? Complicating matters, the picture's page also states that the picture is licenced und a Creative Common by-sa licence, which does not exclude commercial work. So is all this just fine or should something be done?
I looked for any answer in the FAQ and elsewhere, but couldn't find anything useful. Any pointers are welcome! --Yooden
• This is decidedly not okay. I have left a message on the uploaders talk page and will list it for deletion if it is not promptly fixed. WAvegetarian (talk) (email) (contribs) 19:18, 10 December 2005 (UTC)
• Seems deletion might be a bit hasty-- the uploader is clearly the same person as the copyright in the corner states. Should be fixed certainly, but doesnt seem deletion worthy IMHO. -Lanoitarus 19:46, 10 December 2005 (UTC)
• If commercial use is not allowed, it's NOT okay, but cc by-sa should work. The fact those do not mix is a problem. - Mgm|(talk) 19:21, 10 December 2005 (UTC)
• Hi! I am the one who did the image and thus the responsible one:). I have fixed this issue on all three images (removing the "non-commercial" text on the description pages and inside the images. I just wanted to ask you guys: Is there any way for me to specify the licence as free for all uses except commercial? I would be very thankful for a reply on my talk page. My regards, Dennis Nilsson. --Dna-Dennis talk - contribs 00:27, 14 December 2005 (UTC)
## Same problem...
Ironically, the above section describing my problem has already grown too long for me to edit it. So, no, just editing sections doesn't work for me! Melchoir 18:31, 10 December 2005 (UTC)
## CatAZ template
Hi, is it possible to sort articles based on the first few letters instead of just the first letter? Example: If I have Mosque Acheh, Mosque Kampong, can I sort using "Mosque A", "Mosque B", etc instead of just "A", "B", etc.? Unlike in English where the word "mosque" is written at the back of the name, eg. "Acheh Mosque", it is reversed to read "Masjid Acheh" in the Malay language.
I have tried using the above template with one letter (with Gflores assistance) and it works. It didn't work when I tried to extend it thus:
[{{SERVER}}{{localurl:{{NAMESPACE}}:{{PAGENAMEE}}|from=Masjid A}} A].
I understand that one way is actually to use: [[Category:Mosque|Acheh, Mosque]] at the bottom of an article, but then again, when there are many users involved, some may not be able to follow. — PM Poon 18:56, 10 December 2005 (UTC)
The category listing includes subheaders for the first letter of the article name, or the first letter of the sort key. If you want the listing to be divided by the first letter of the mosque name, as far as I know the only option is to add the sort key as you suggest. If you don't add a sort key, they'll all appear under "M", sorted alphabetically. The "index" shown by the template does not affect the appearance of the category listing, but was created to match it. If you don't add the sort key, and there are hundreds of entries in the category, the template approach could produce an index allowing a user to traverse to the indicated point in the category listing (still under "M" in the category listing). I believe this would "work", but it sounds like it might not do what you're looking for. -- Rick Block (talk) 16:58, 11 December 2005 (UTC)
Hi Rick Block, actually it is alright if all the articles in the category page begins with "Masjid" (meaning "mosque"). I am trying to use the template, CatAZ, to navigate the category page. Apparently it cannot work with more than one letter. Do you know how to modify the template so that it can work? Thanks. — PM Poon 19:52, 12 December 2005 (UTC)
## Citation
An article I just wrote, Q TV, has been flagged as in need of citations. However, the article only contains basic information obvious from watching the channel such as Channel number, content, etc (ie: not sourced information). What should I do for the citation? smurrayinchester(User), (Ho Ho Ho!) 22:24, 10 December 2005 (UTC)
I believe that the policy is that {{unreferenced}} shouldn't be applied where there is also a stub template. However, I thiink that watching the channel could well be interpreted as original research, and to the extent that that is not the case, the television channel transmissions themselves are what should be quoted as the source. The problem with this is that they are ephemeral and not easily available to all readers of Wikipedia, so a more permanent and available source would be highly desirable and surely exists. The information is not obvious to someone with the technical knowledge (very little) needed to understand the article, unless they also subscribe. I believe that one suggested test of a valid source is that the information should still be verifiable from it in 10 years time.
The info-box does include a reference, which should be given a full citation in the References section, as well as the numbered link in the info-box. --David Woolley 00:34, 11 December 2005 (UTC)
## Where do I go to discuss the ban of anonymous users creating articles?
Where do I go to discuss the ban of anonymous users creating articles? --anon
• As is often the case on Wikipedia, discussion is happening in a multitude of different places, in a comparatively unorganized fashion.
The central locations that I am aware of include:
You may also wish to look at:
-- Creidieki 00:25, 11 December 2005 (UTC)
Which is the best place? --anon
If what you want to do is challenge rather than just discuss, you might as well share your reasons here. There's a good chance that this exact point was discussed and a conclusion already reached, which someone can share. If you disagree, though, you'd need to go to one of the other places for a discussion. Notinasnaid 11:25, 11 December 2005 (UTC)
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2014-10-02 12:00:00
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http://math.stackexchange.com/tags/puzzle/hot
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# Tag Info
7
Just rearrange them and notice that the bold triangle is right and isosceles: Another proof of $\arctan 1=\arctan\frac{1}{2}+\arctan\frac{1}{3}$ comes from: $$(3+i)(2+i) = 5+5i$$ by switching to arguments.
4
A step of one meter perpendicular to the radius will increase the first friend's distance from the center, from $r$ to $\sqrt{r^2+1}$; and whether the step is clockwise or counterclockwise makes no difference. That is, it increases the square of the distance from the center by one square meter, and the second friend's instruction is irrelevant. It's easy ...
3
Isn't it much simpler to assign a value of 1 to the daughter, 2 to the wife and 4 to son? Adding those values totals to 7. The ratios are then easily derived by placing the assigned values over the total to yield: 1/7, 2/7 and 4/7
3
The corner tiles have 2 ways to move The side tiles have 3 ways to move The middle tiles have 4 ways to move 2 3 3 2 2 3 3 3 2 ... 3 4 4 3 3 4 4 4 3 3 4 4 3 3 4 4 4 3 2 3 3 2 3 4 4 4 3 2 3 3 3 2 Then the formula for different ways to make a $2048$ tile on $(n * n)$ square of $1024$ tiles is: $4 * 2 + (n - 2) *... 3 The following two questions are equivalent: "Can the cards be folded to put them in increasing order, when they are labeled in a specified arbitrary order?" "Can the cards be folded to produce a specified arbitrary order, when they are labeled in increasing order?" The relevant result was proved by Koehler in 1968 ("Folding a Strip of Stamps"): An ... 3 It is not entirely unambiguously clear to me what those expressions should mean. The dots suggest something of a limiting process, so I'd interpret them as limits. The expression for$s$can be viewed as a limit as follows: Define a sequence$s_0,s_1,\ldots$as $$s_0:=1\qquad\text{ and }\qquad s_{n+1}:=\sum_{i=1}^{s_n}1\ \text{ for }\ n\geq0.$$ Then$s$can ... 3 There are five odd digits in total and four of them must occur in the four unit places. Also, some odd digit must occur among the tens places of the three summands as$2+4+6$would be too big. Then the tens of the sum must be even, at most$8$. So the odd tens digit is at most$8-4-2$, hence$1$is in some tens place and our four odd unit digits are$3,5,7,...
2
my hunch is this. Each weighing can turn out one of 3 ways -- be left side heavy, right side heavy or ballance. If we put the coins in a line, there are ${11\choose 7} = 28$ ways the counterfeits could be arranged. But each coin could be one of 8 different weights! I think there are $28\cdot8!$ different distributions to identify. $n > \log_3 28\... 2 Consider following triangle: As$BC = AC$we have$\angle ABC = \angle CAB$or $$\pi - \gamma - \beta = \gamma - \frac{\pi}{2} + \beta \iff \gamma + \beta = \frac{3\pi}{4}$$ (here$\gamma$is red angle from picture in question and$\beta$is yellow one). It's obvious that green angle from question (detote it as$\alpha$) is equal to$\frac{\pi}{4}$. ... 2 Because$N=1$, the equation is:$300S + 3X = 2020 + 170I +2E$Let's write it$R(S,X) = L(I,E)$. We notice that$L(5,0)=2870$and$R(9,9)=2727 < L(5,0)$so$I<5$. Let's check the remaining 5 possible values for$I$:$I=0$Then$2020 \leq L(0,E) \leq 2038$But$R(7,0)=2100$and$R(6,9) = 1827$so we cannot have$R(S,X) = L(0,E)$. Hence$I=0$... 2 $$3\times\overline{SIX}=2\times\overline{NINE}$$ As you wrote, we have$N=1$. Also, we know that$X$is even. Let us separate it into cases. In the following, let$[n]$be the right-most digit of$n$. Case 1 :$X=0$. Then,$E=0,5$from$[2E]=[3X]=0$. If$E=0$, then since the right-most two digits of$3\times\overline{IX}$has to be$20$, we have to have$[...
2
For this sort of problem, if possible, I will be lazy and ask a computer to find all solutions for me. If we ignore commutativity and associativity of addition and multiplication, there are $30965760$ ways to write down an arithmetic expression involving $6$ variables. Out of all these choices, $2400$ of them will return $828$. If we use the fact the ...
1
The problem is actually already solved by Jyrki's comment, since the only way to satisfy the given conditions is that the $3$ voters have the cyclical preferences given in his example, or the opposite preferences. Thus you just need to count the number of times each of the candidates wins under the proposed "solution", given such a preference set. As you ...
1
This question should be well-known and easy to find on the internet. related pages are for example; http://www.mathpages.com/home/kmath668/kmath668.htm http://physics.stackexchange.com/questions/2072/on-this-infinite-grid-of-resistors-whats-the-equivalent-resistance
1
@Jack D'Aurizio thanks for your solution and suggestions i found a little bit different solution from yours :)
1
He who starts with a multiple of three loses because his opponent can maintain this property until the end. He who starts with a non multiple of three wins by leaving the opponent with a multiple of three. $\color{blue}9\to8|7\to\color{blue}6\to5|4\to\color{blue}3\to2|1\to\color{blue}0$ $\color{blue}{10}\to9\to\color{blue}{8|7}\to6\to\color{blue}{5|4}\... 1 The key to this game is modular arithmetic. It is essentially the same game if it has$0,3,6,...,$or$3k$coins,$1,4,...,$or$3k+1$coins, and$2,5, ... ,$or$3k+2$coins. The optimal strategy is to always keep the number of coins$n$on the table such that$n\equiv 0\pmod 3.$This guarantees that when there are only$3$coins left, it is the other ... 1 Unless there's some other unstated constraint, the problem doesn't have a unique solution. Even if you demand an integer at every step of the calculation, you get 301 distinct$(a,\ldots,i)$tuples that qualify. My guess is that the constructor didn't realize (or care) that there is more than one solution. Writing a small script would be the quickest way to ... 1 Without thinking too much of how they would be defined, you are essentially looking for solutions to $$s = \sum_{n=1}^s 1$$ and $$t = \int_0^t dx$$ which both can be any value at all (although they must be integral in the first case). So they are certainly not unique... 1 This is not an answer, but input for inspiration on the question. I've looked at bingo puzzles with the same rules, but with smaller cards. That is, I've looked at cards with the sizes$N*N$where$N = 2$(with the numbers$1-4$),$N=3$(with the numbers$1 - 9$) and$N=4$(with the numbers$1 - 16\$). As a guideline for how many calls were made in each case,...
1
I guess my idea is similar to Christian Blatter above. I did a R simulation with the assumptions that buses arrive promptly every 10 and 15 minutes, respectively. However, the interval time among buses is fixed with uniformly distributed starting times. I simulate buses between [0,10000] minutes and the guy arriving at the bus stop at time t in [50,9950] and ...
1
More mathematically, it can be done as : The minute hand moves 360 degrees in 60 minutes. This means that the angle of the minute hand is given by 6t, where t is number of minutes past midnight. The hour hand moves 30 degrees in 60 minutes. This means that the angle of the hours hand is given by 0.5t. The hands start together at midnight. The first time ...
Only top voted, non community-wiki answers of a minimum length are eligible
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2016-07-01 21:12:28
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https://socratic.org/questions/what-is-the-slope-of-the-line-passing-through-the-following-points-1-1-1-2-1#311557
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# What is the slope of the line passing through the following points: (1,-1) , (1/2, 1)?
Sep 18, 2016
slope = - 4
#### Explanation:
To find the slope use the $\textcolor{b l u e}{\text{gradient formula}}$
$\textcolor{red}{\overline{\underline{| \textcolor{w h i t e}{\frac{a}{a}} \textcolor{b l a c k}{m = \frac{{y}_{2} - {y}_{1}}{{x}_{2} - {x}_{1}}} \textcolor{w h i t e}{\frac{a}{a}} |}}}$
where m represents the slope and $\left({x}_{1} , {y}_{1}\right) , \left({x}_{2} , {y}_{2}\right) \text{ 2 coordinate points}$
here the 2 points are $\left(1 , - 1\right) \text{ and } \left(\frac{1}{2} , 1\right)$
let $\left({x}_{1} , {y}_{1}\right) = \left(1 , - 1\right) \text{ and } \left({x}_{2} , {y}_{2}\right) = \left(\frac{1}{2} , 1\right)$
$m = \frac{1 - \left(- 1\right)}{\frac{1}{2} - 1} = \frac{2}{- \frac{1}{2}} = - 4 \text{ is the slope of the line}$
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2022-12-09 17:09:37
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http://www.baitstick.com/images/pdf.php?q=pdf-power-definitions-and-the-physical-mechanism-of-power-flow-2010/
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# Pdf Power Definitions And The Physical Mechanism Of Power Flow 2010
### Pdf Power Definitions And The Physical Mechanism Of Power Flow 2010
by Laura 4.3
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2020-02-28 02:14:53
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https://projecteuclid.org/euclid.acta/1560966692
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## Acta Mathematica
### Algebraic actions of discrete groups: the $p$-adic method
#### Abstract
We study groups of automorphisms and birational transformations of quasi-projective varieties. Two methods are combined; the first one is based on $p$-adic analysis, the second makes use of isoperimetric inequalities and Lang–Weil estimates. For instance, we show that, if $\mathsf{SL}_n(\mathbf{Z})$ acts faithfully on a complex quasi-projective variety $X$ by birational transformations, then $\mathrm{dim}(X) \geqslant n-1$ and $X$ is rational if $\mathrm{dim}(X) = n-1$.
#### Article information
Source
Acta Math., Volume 220, Number 2 (2018), 239-295.
Dates
Revised: 3 February 2018
First available in Project Euclid: 19 June 2019
https://projecteuclid.org/euclid.acta/1560966692
Digital Object Identifier
doi:10.4310/ACTA.2018.v220.n2.a2
Mathematical Reviews number (MathSciNet)
MR3849285
Zentralblatt MATH identifier
06925265
#### Citation
Cantat, Serge; Xie, Junyi. Algebraic actions of discrete groups: the $p$-adic method. Acta Math. 220 (2018), no. 2, 239--295. doi:10.4310/ACTA.2018.v220.n2.a2. https://projecteuclid.org/euclid.acta/1560966692
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2019-10-22 08:18:57
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http://projects.tevs.eu/osgPPU/wiki/TracStandalone?action=diff&version=2
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# Changes between Version 1 and Version 2 of TracStandalone
Ignore:
Timestamp:
04/18/11 00:07:14 (10 years ago)
Comment:
--
### Legend:
Unmodified
v1 = Tracd = Tracd is a lightweight standalone Trac web server. In most cases it's easier to setup and runs faster than the [wiki:TracCgi CGI script]. Tracd is a lightweight standalone Trac web server. It can be used in a variety of situations, from a test or development server to a multiprocess setup behind another web server used as a load balancer. == Pros == * Fewer dependencies: You don't need to install apache or any other web-server. * Fast: Should be almost as fast as the [wiki:TracModPython mod_python] version (and much faster than the [wiki:TracCgi CGI]). * Fast: Should be almost as fast as the [wiki:TracModPython mod_python] version (and much faster than the [wiki:TracCgi CGI]), even more so since version 0.12 where the HTTP/1.1 version of the protocol is enabled by default * Automatic reloading: For development, Tracd can be used in ''auto_reload'' mode, which will automatically restart the server whenever you make a change to the code (in Trac itself or in a plugin). == Cons == * Fewer features: Tracd implements a very simple web-server and is not as configurable or as scalable as Apache HTTPD. * Fewer features: Tracd implements a very simple web-server and is not as configurable or as scalable as Apache httpd. * No native HTTPS support: [http://www.rickk.com/sslwrap/ sslwrap] can be used instead, or [http://trac.edgewall.org/wiki/STunnelTracd stunnel -- a tutorial on how to use stunnel with tracd] or Apache with mod_proxy. $tracd -p 8080 /path/to/project }}} Stricly speaking this will make your Trac accessible to everybody from your network rather than ''localhost only''. To truly limit it use ''--hostname'' option. {{{$ tracd --hostname=localhost -p 8080 /path/to/project }}} With more than one project. (http://localhost:8080/project1/ and http://localhost:8080/project2/) {{{ }}} To exit the server on Windows, be sure to use {{{CTRL-BREAK}}} -- using {{{CTRL-C}}} will leave a Python process running in the background. == Installing as a Windows Service == === Option 1 === To install as a Windows service, get the [http://www.google.com/search?q=srvany.exe SRVANY] utility and run: {{{ C:\path\to\instsrv.exe tracd C:\path\to\srvany.exe reg add HKLM\SYSTEM\CurrentControlSet\Services\tracd\Parameters /v Application /d "\"C:\path\to\python.exe\" \"C:\path\to\python\scripts\tracd-script.py\" " net start tracd }}} '''DO NOT''' use {{{tracd.exe}}}. Instead register {{{python.exe}}} directly with {{{tracd-script.py}}} as a parameter. If you use {{{tracd.exe}}}, it will spawn the python process without SRVANY's knowledge. This python process will survive a {{{net stop tracd}}}. If you want tracd to start automatically when you boot Windows, do: {{{ sc config tracd start= auto }}} The spacing here is important. {{{#!div Once the service is installed, it might be simpler to run the Registry Editor rather than use the reg add command documented above. Navigate to:[[BR]] HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\tracd\Parameters Three (string) parameters are provided: ||!AppDirectory ||C:\Python26\ || ||Application ||python.exe || ||!AppParameters ||scripts\tracd-script.py -p 8080 ... || Note that, if the !AppDirectory is set as above, the paths of the executable ''and'' of the script name and parameter values are relative to the directory. This makes updating Python a little simpler because the change can be limited, here, to a single point. (This is true for the path to the .htpasswd file, as well, despite the documentation calling out the /full/path/to/htpasswd; however, you may not wish to store that file under the Python directory.) }}} For Windows 7 User, srvany.exe may not be an option, so you can use [http://www.google.com/search?q=winserv.exe WINSERV] utility and run: {{{ "C:\path\to\winserv.exe" install tracd -displayname "tracd" -start auto "C:\path\to\python.exe" c:\path\to\python\scripts\tracd-script.py " net start tracd }}} === Option 2 === Use [http://trac-hacks.org/wiki/WindowsServiceScript WindowsServiceScript], available at [http://trac-hacks.org/ Trac Hacks]. Installs, removes, starts, stops, etc. your Trac service. == Using Authentication == Tracd provides support for both Basic and Digest authentication. The default is to use Digest; to use Basic authentication, replace --auth with --basic-auth in the examples below, and omit the realm. ''Support for Basic authentication was added in version 0.9.'' If the file /path/to/users.htdigest contains user accounts for project1 with the realm "mycompany.com", you'd use the following command-line to start tracd: {{{ $tracd -p 8080 --auth project1,/path/to/users.htdigest,mycompany.com /path/to/project1 }}} '''Note''': the project "name" passed to the --auth option is the base name of the project environment directory. Of course, the digest file can be be shared so that it is used for more than one project: Tracd provides support for both Basic and Digest authentication. Digest is considered more secure. The examples below use Digest; to use Basic authentication, replace --auth with --basic-auth in the command line. The general format for using authentication is: {{{$ tracd -p port --auth="base_project_dir,password_file_path,realm" project_path }}} where: * '''base_project_dir''': the base directory of the project specified as follows: * when serving multiple projects: ''relative'' to the project_path * when serving only a single project (-s): the name of the project directory Don't use an absolute path here as this won't work. ''Note:'' This parameter is case-sensitive even for environments on Windows. * '''password_file_path''': path to the password file * '''realm''': the realm name (can be anything) * '''project_path''': path of the project * **--auth** in the above means use Digest authentication, replace --auth with --basic-auth if you want to use Basic auth. Although Basic authentication does not require a "realm", the command parser does, so the second comma is required, followed directly by the closing quote for an empty realm name. Examples: {{{ $tracd -p 8080 \ --auth project1,/path/to/users.htdigest,mycompany.com \ --auth project2,/path/to/users.htdigest,mycompany.com \ --auth="project1,/path/to/passwordfile,mycompany.com" /path/to/project1 }}} Of course, the password file can be be shared so that it is used for more than one project: {{{$ tracd -p 8080 \ --auth="project1,/path/to/passwordfile,mycompany.com" \ --auth="project2,/path/to/passwordfile,mycompany.com" \ /path/to/project1 /path/to/project2 }}} Another way to share the digest file is to specify "*" for the project name: Another way to share the password file is to specify "*" for the project name: {{{ $tracd -p 8080 \ --auth *,/path/to/users.htdigest,mycompany.com \ --auth="*,/path/to/users.htdigest,mycompany.com" \ /path/to/project1 /path/to/project2 }}} == How to set up an htdigest password file == === Basic Authorization: Using a htpasswd password file === This section describes how to use tracd with Apache .htpasswd files. To create a .htpasswd file use Apache's htpasswd command (see [#GeneratingPasswordsWithoutApache below] for a method to create these files without using Apache): {{{$ sudo htpasswd -c /path/to/env/.htpasswd username }}} then for additional users: {{{ $sudo htpasswd /path/to/env/.htpasswd username2 }}} Then to start tracd run something like this: {{{$ tracd -p 8080 --basic-auth="projectdirname,/fullpath/environmentname/.htpasswd,realmname" /fullpath/environmentname }}} For example: {{{ $tracd -p 8080 --basic-auth="testenv,/srv/tracenv/testenv/.htpasswd,My Test Env" /srv/tracenv/testenv }}} ''Note:'' You might need to pass "-m" as a parameter to htpasswd on some platforms (OpenBSD). === Digest authentication: Using a htdigest password file === If you have Apache available, you can use the htdigest command to generate the password file. Type 'htdigest' to get some usage instructions, or read [http://httpd.apache.org/docs/2.0/programs/htdigest.html this page] from the Apache manual to get precise instructions. You'll be prompted for a password to enter for each user that you create. For the name of the password file, you can use whatever you like, but if you use something like users.htdigest it will remind you what the file contains. As a suggestion, put it in your /conf folder along with the [TracIni trac.ini] file. Note that you can start tracd without the --auth argument, but if you click on the ''Login'' link you will get an error. == Generating Passwords Without Apache == If you don't have Apache available, you can use this simple Python script to generate your passwords: {{{ === Generating Passwords Without Apache === Basic Authorization can be accomplished via this [http://www.4webhelp.net/us/password.php online HTTP Password generator]. Copy the generated password-hash line to the .htpasswd file on your system. You can use this simple Python script to generate a '''digest''' password file: {{{ #!python from optparse import OptionParser import md5 # The md5 module is deprecated in Python 2.5 try: from hashlib import md5 except ImportError: from md5 import md5 realm = 'trac' # build the options parser.add_option("-p", "--password",action="store", dest="password", type = "string", help="the password to use") parser.add_option("-r", "--realm",action="store", dest="realm", type = "string", help="the realm in which to create the digest") (options, args) = parser.parse_args() if (options.username is None) or (options.password is None): parser.error("You must supply both the username and password") if (options.realm is not None): realm = options.realm # Generate the string to enter into the htdigest file realm = 'trac' kd = lambda x: md5.md5(':'.join(x)).hexdigest() kd = lambda x: md5(':'.join(x)).hexdigest() print ':'.join((options.username, realm, kd([options.username, realm, options.password]))) }}} Note: If you use the above script you must use the --auth option to tracd, not --basic-auth, and you must set the realm in the --auth value to 'trac' (without the quotes). Example usage (assuming you saved the script as trac-digest.py): {{{ python trac-digest.py -u username -p password >> c:\digest.txt python tracd --port 8000 --auth proj_name,c:\digest.txt,trac c:\path\to\proj_name Note: If you use the above script you must set the realm in the --auth argument to '''trac'''. Example usage (assuming you saved the script as trac-digest.py): {{{$ python trac-digest.py -u username -p password >> c:\digest.txt $tracd --port 8000 --auth=proj_name,c:\digest.txt,trac c:\path\to\proj_name }}} ==== Using md5sum It is possible to use md5sum utility to generate digest-password file: {{{$ printf "${user}:trac:${password}" | md5sum - >>user.htdigest }}} and manually delete " -" from the end and add "${user}:trac:" to the start of line from 'to-file'. == Reference == Here's the online help, as a reminder (tracd --help): {{{ Usage: tracd [options] [projenv] ... Options: --version show program's version number and exit -h, --help show this help message and exit -a DIGESTAUTH, --auth=DIGESTAUTH [projectdir],[htdigest_file],[realm] --basic-auth=BASICAUTH [projectdir],[htpasswd_file],[realm] -p PORT, --port=PORT the port number to bind to -b HOSTNAME, --hostname=HOSTNAME the host name or IP address to bind to --protocol=PROTOCOL http|scgi|ajp -q, --unquote unquote PATH_INFO (may be needed when using ajp) --http10 use HTTP/1.0 protocol version (default) --http11 use HTTP/1.1 protocol version instead of HTTP/1.0 -e PARENTDIR, --env-parent-dir=PARENTDIR parent directory of the project environments --base-path=BASE_PATH the initial portion of the request URL's "path" -r, --auto-reload restart automatically when sources are modified -s, --single-env only serve a single project without the project list }}} === Serving static content === If tracd is the only webserver used for the project, If tracd is the only web server used for the project, it can also be used to distribute static content (tarballs, Doxygen documentation, etc.) Example: given a $TRAC_ENV/htdocs/software-0.1.tar.gz file, the corresponding relative URL would be //chrome/site/software-0.1.tar.gz, which in turn can be written using the relative link syntax in the Wiki: [//chrome/site/software-0.1.tar.gz] The development version of Trac supports a new htdocs: TracLinks syntax for the above. With this, the example link above can be written simply htdocs:software-0.1.tar.gz. which in turn can be written as htdocs:software-0.1.tar.gz (TracLinks syntax) or [//chrome/site/software-0.1.tar.gz] (relative link syntax). ''Support for htdocs: TracLinks syntax was added in version 0.10'' === Using tracd behind a proxy In some situations when you choose to use tracd behind Apache or another web server. In this situation, you might experience issues with redirects, like being redirected to URLs with the wrong host or protocol. In this case (and only in this case), setting the [trac] use_base_url_for_redirect to true can help, as this will force Trac to use the value of [trac] base_url for doing the redirects. If you're using the AJP protocol to connect with tracd (which is possible if you have flup installed), then you might experience problems with double quoting. Consider adding the --unquote parameter. See also [trac:TracOnWindowsIisAjp], [trac:TracNginxRecipe]. === Serving a different base path than / === Tracd supports serving projects with different base urls than /. The parameter name to change this is {{{ \$ tracd --base-path=/some/path }}} ---- See also: TracInstall, TracCgi, TracModPython, TracGuide ---- '''Translation:''' * [https://opensvn.csie.org/traccgi/trac_rus/wiki/StandAloneTracForTeapot Russian] (??????? ?? ???????) See also: TracInstall, TracCgi, TracModPython, TracGuide, [trac:TracOnWindowsStandalone#RunningTracdasservice Running tracd.exe as a Windows service]
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2021-03-07 11:33:34
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https://www.talkstats.com/threads/state-reason-for-using-one-tail-in-the-analysis-of-variance-test.48224/
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# state reason for using one tail in the analysis of variance test ?
#### Cynderella
##### New Member
I think in this way that
since in anova we partition the total variability into various independent components ,
and since the Mean square of this components follow chi-square distribution,
and since the ratio of two chi-square distribution follows F- distribution,
and since F- distribution is a one tailed test,
we use one tail in the analysis of variance test .
Does it make sense ?
#### Miner
##### TS Contributor
I think you over analyzed it. Look at it from your null and alternate hypotheses. Your null hypothesis is that the variance due to the factor is <= to the variance due to the random error. Your alternate hypothesis is the variance due to the factor is > that due to random error. This means a one tailed test.
A two-tailed test means that you care only that they are different. Why would you care whether the variance due to the factor was < than that due to random error?
#### Dason
##### Ambassador to the humans
and since F- distribution is a one tailed test,
The F-distribution is a distribution - not a test. You can most certainly use a two-tailed test for test statistics that follow the F distribution - but most of the time this isn't something that makes sense to do.
#### trinker
##### ggplot2orBust
Can you even have a directional hypothesis with an ANOVA that uses the F distribution (at least with more than 2 groups)?
#### Cynderella
##### New Member
Look at it from your null and alternate hypotheses. Your null hypothesis is that the variance due to the factor is <= to the variance due to the random error. Your alternate hypothesis is the variance due to the factor is > that due to random error.
My null hypothesis is $$\mu_1=\mu_2=...=\mu_a$$ and alternative hypothesis is $$\mu_i\neq\mu_j$$ for some $$i\neq j$$. And I did ANOVA test for testing the hypothesis.
Isn't the hypothesis two-tailed test ?
#### rogojel
##### TS Contributor
My null hypothesis is $$\mu_1=\mu_2=...=\mu_a$$ and alternative hypothesis is $$\mu_i\neq\mu_j$$ for some $$i\neq j$$. And I did ANOVA test for testing the hypothesis.
Isn't the hypothesis two-tailed test ?
As far as I know with ANOVA you are actually testing the consequence of this hypothesis on the variance structure. If the assumption that at leastbsome group means are different is a good explanation of the total variance in the data then the original null is rejected.
So, we really test whether the model with different means has a much smaller residual variance ( contribution to the sum of squares really) then the model with the same means. The test for this is one sided.
regards
rogojel
#### Miner
##### TS Contributor
My null hypothesis is $$\mu_1=\mu_2=...=\mu_a$$ and alternative hypothesis is $$\mu_i\neq\mu_j$$ for some $$i\neq j$$. And I did ANOVA test for testing the hypothesis.
Isn't the hypothesis two-tailed test ?
Technically, you are correct about the hypotheses. However, you must look at the way that ANOVA tests these hypotheses. The F-test is actually a ratio of the s^2 due to the effect of a factor divided by the s^2 due to random variation. Therefore, in effect the null hypothesis becomes s^2 effect <= s^2 random, and the alternate, in effect, becomes s^2 effect > s^2 random, which is a 1-tailed test using the F distribution.
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2022-01-25 19:50:00
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https://blog.perwagnernielsen.dk/logistic_regression_1.html
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## Logistic Regression 1
How does logistic regression work in Python. This is the story.
We are going to look into the theory and application of logistic regression. This story will follow the outline of the course from lazy programmer here: https://lazyprogrammer.me/deep-learning-courses/.
# Theory
We are still using the formula for from linear regression $$y=ax+b$$, but in machine learning we often use different wording than what we typically do in statistics.
$$(x,y) -> (x_1, x_2) = \textbf{x}$$
The constant term is renamed to $$w_1$$ and the bias/intercept to $$w_0$$, so we get:
$$h(\textbf{x})=w_0 + w_1x_1 + w_2x_2$$
making h() a linear combination of the components of x. In vector form we write $$h(\textbf{x})=\textbf{w}^t\textbf{x}$$
### Calculate the output of a neuron
The sigmoid function we will use: $$\sigma(z) = \frac{1} {{1+e^{-z}}}, \in{(0,1)}$$, which can be written as: $$\sigma(\textbf{w}^t\textbf{x})$$
To do the logistic regression in Python, we do this:
import numpy as np
N = 100
D = 2
X = np.random.randn(N, D) # The dataset
ones = np.array([[1]*N]).T # the bias/intercept
Xb = np.concatenate((ones, X), axis=1) # just the dataset as a N x 3 matrix
w = np.random.randn(D + 1) # weights, must be a 3 x 1 matrix
# Calculate the dot product between x and w
z = Xb.dot(w) # Will be a (Nx3) * (3x1) = N x 1 matrix
def sigmoid(z):
return 1 / (1 + np.exp(-z))
print(sigmoid(z))
# Example with ecommerce data
### Example data
The data looks something like this:
import numpy as np
import pandas as pd
The 'visit_duration' is a real number in minutes of how long the user was on the site.
'time_of_day" is a category label:
0: from 0 to 6
1: from 6 to 12
2: from 12 to 18
3: from 18 to 24
We will do 'one hot encoding' for this category:
0-6 / 6-12 / 12-18 / 18-24
1 0 0 0
0 1 0 0
0 0 1 0
0 0 0 1
User action is the action we want to predict:
0: bounce
2: begin_checkout
3: finish_checkout
### Normalize
Scale and distance are important so we need to normalize the n_products_viewed and the visitor_duration numbers, which can be done according to the formula $$Z= \frac{(X-\mu)} {\sigma}$$
## Pre-process data
### Normalize numerical columns
We have 2 numerical columns that we want to normalize, the first and second ones. We will create a function to do this:
def normalize_row(row):
"""Takes a row and returns a normalized row"""
return (row - row.mean()) / row.std()
We then create a new X matrix with the first 2 rows normalized:
data = df.to_numpy() # makes the dataframe into a numpy array
X = data[:, :-1] # All the X variables
Y = data[:, -1] # The dependent Y variable
# Normalize rows 1 and 2 in place
X[:,1] = normalize_row(X[:,1])
X[:,2] = normalize_row(X[:,2])
The we do the one how encoding for the time dimension:
## The 'time of day' category column. We want to use the one-hot encoding.
N, D = X.shape # D = 5 as there are 5 columns in X
X2 = np.zeros((N, D+3)) # D + 3 = 5 + 3=8; We will have the existing 4 categories + 4 'one hot encodings' for the 'time_of_day' column
X2[:, 0:(D-1)] = X[:, 0:(D-1)] # X2's first 4 columns just contains the original 4 X columns
# The one hot encoding
for n in range(N):
time_of_day = int(X[n, D-1]) # D-1=4, the 4th column in the original X matrix is the 'time_of_day' column (we count from zero)
X2[n,time_of_day + D-1] = 1 # time_of_day + (D-1) = the category used in the one hot encoding; and we set that == 1
Additionally, in logistic regression, we are only operating with 2 'categories' for the dependent variable (Y), in our case 'bounce' or 'add_to_card', which have values 0 and 1 respectively. We filter our X2 and Y variable to only include rows with these two Y categories:
X2 = X[Y <=1 ]
Y = Y[Y <= 1]
## Make prediction
We start by creating the weights and bias for our predictive model. The weights will initially just be random numbers and the bias is set to zero:
D = X2.shape[1] # Getting the number of columns in our X2. We will use this to create our initial weights
W = np.random.randn(D) # Our weights matrix, just random numbers
b = 0 # Bias term.
We will create 2 helper functions to assist us with our prediction, a sigmoid function and a prediction function.
Sigmoid function
def sigmoid(a):
return 1/(1 + np.exp(-a))
Prediction function
def forward(X, W, b):
return sigmoid(X.dot(W) + b)
We make the prediction:
P_Y_given_X = forward(X, W, b)
predictions = np.round(P_Y_given_X)
The classification rate function:
def classification_rate(Y, P):
return np.mean(Y == P)
Running all this, we can get something like this (depending on your random weights):
print("Score:", classification_rate(Y, predictions))
Score: 0.30402010050251255
# Training and solving for optimal weights
## The cross entropy error function
What do we want out of an error function for a logistic error function: * Should be 0 if there is no error * > 0 if there is an error * Magnitude means higher cost
The cross-entropy error function is:
$$J = -{ t * log(y) + (1-t) * log(1-y)}$$
Where:
J: is the error
t: is the target
y: is the prediction, or the output from the logistic regression
Lets try and set t = 1:
$$J = -{ t * log(y) + (1-t) * log(1-y)}$$
$$J = -{ 1 * log(y) + (1-1) * log(1-y)} <=>$$
$$J = -{ log(y) }$$
So only the first term really matter in this case. If we set t=0, we get:
$$J = -{ t * log(y) + (1-t) * log(1-y)}$$
$$J = -{ 0 * log(y) + (1-0) * log(1-y)} <=>$$
$$J = -{ log(1-y) }$$
So only the 2nd term matter.
If we try a few examples this might make more sense.
With t=1 and y=1 (our real value (target) was 1 and the prediction was also one), then our error becomes:
$$J = -{ log(1) } = 0$$
Which intuitively makes sense, we hit the target so the error becomes zero. The same thing happens if we have t=0 and y = 0.
What if our prediction is just a bit off? say t=1 but y=0.9? Then we get:
$$J = -{ 1 * log(0.9) } = -(-0.11) = 0.11$$
So a relatively small error.
What if we have a large difference between t and y, say t = 1 and y = 0.2?
$$J = -{ 1 * log(0.27) } = -(-1.31) = 1.31$$
Giving us a much larger error.
For the calculations we typically want the total cross entropy error which we get by summing over all the errors:
$$J = -\sum_{n=1}^N( t * log(y) + (1-t) * log(1-y))$$
### Making a function
We are gonna make use of the fact that the cross entropy error function simplifies for t = 0 and t = 1. We can then do this:
def cross_entropy_error(T, Y):
"""Calculate the cross entropy error.
T: Target
Y: Prediction
"""
N = T.shape[0]
E = 0
for i in range(N):
if T[i] == 1:
E -= np.log(Y[i])
else:
E -= np.log(1 - Y[i])
return E
### Calculation example in code
N = 100
D = 2
X = np.random.randn(N, D) # Random Xs with same mean and variance
X[:50, :] = X[:50, :] - 2 * np.ones((50, D)) # make half 2*1 lower than mean
X[50:, :] = X[50:, :] + 2 * np.ones((50, D)) # make other half 2*1 higher than mean
T = np.array([0] * 50 + [1] * 50) # Target, first 50 are 50 then next 50 one.
# Create X matrix with constants term
ones = np.array([[1] * N]).T
Xb = np.concatenate((ones, X), axis=1)
# Randomly initialize the weights
w = np.random.randn(D + 1)
# Calculate model output
z = Xb.dot(w)
Y = sigmoid(z)
print(cross_entropy_error(T, Y))
158.89255979864652
Let's try and visualize this solution. We first import matplotlib:
import matplotlib.pyplot as plt
# The closed form solution
w = np.array([0, 4, 4]) # bias is zero
# The line: y = -x
plt.scatter(X[:,0], X[:,1], c=T, s=100, alpha=0.5) # c=T for the colors
x_axis = np.linspace(-6, 6, 100)
y_axis = -x_axis
plt.plot(x_axis, y_axis)
plt.show()
## Cross entropy error and log likelyhood
An interesting consequense of having the cross entropy error function the way we have it is that maximizing the log likelihood of our sigmoid function is the same as minimizing the cross entropy error function.
(Will not show the math here though)
### Theory
The basic idea of gradient decent is that we take small steps in the direction of the derivative. So we update our weights with a small step size (choosen by us) and rerun until our derivative is so close to zero as we are comfortable with.
How to choose the learning rate? No scientific way, just try.
$$J = -\sum_{n=1}^N( t_n * log(y_n) + (1-t_n) * log(1-y_n))$$
The derivative becomes:
$$\frac{\delta J}{\delta y_n} = -t_n \frac{1}{y_n} + (1-t_n) \frac{1}{1-y_n} (-1)$$
The derivative of the sigmoid becomes:
$$y_n = \sigma(a_n) = \frac{1}{1 + e^{-a_n}}$$
$$\frac{\delta y_n}{\delta a_n} = \frac{-1}{(1+e^{-a_n})^{2}}(e^{-a_n}) (-1)=y_n(1-y_n)$$
The deriviative of a with respect to w (the activation with regards to the weights):
$$a_n = w^t x_n$$
$$a_n = w_0 x_{n_0} + w_1 x_{n_1} + w_2 x_{n_2} + ...$$
$$\frac{\delta a_n}{\delta w_i} = x_{n_i}$$
Putting it all together:
$$\frac{\delta J}{\delta w_i} = \sum_{n=1}^N (y_n - t_n) x_{n_i}$$
In vector form:
$$\frac{\delta J}{\delta w} = X^T (Y - T)$$
### In code
N = 100
D = 2
X = np.random.randn(N, D) # Random Xs with same mean and variance
X[:50, :] = X[:50, :] - 2 * np.ones((50, D)) # make half 2*1 lower than mean
X[50:, :] = X[50:, :] + 2 * np.ones((50, D)) # make other half 2*1 higher than mean
T = np.array([0] * 50 + [1] * 50) # Target, first 50 are 50 then next 50 one.
# Create X matrix with constants term
ones = np.array([[1] * N]).T
Xb = np.concatenate((ones, X), axis=1)
# Randomly initialize the weights
w = np.random.randn(D + 1)
# Calculate model output
z = Xb.dot(w)
Y = sigmoid(z)
learning_rate = 0.1
# Do 100 iterations of gradient decent
for i in range(100):
if i % 10 == 0:
ce_error = cross_entropy_error(T, Y)
print(f"Cross entropy error: {ce_error}")
w += learning_rate * np.dot((T - Y).T, Xb)
Y = sigmoid(Xb.dot(w))
print(f"Final w: {w}")
`
# References
https://lazyprogrammer.me/deep-learning-courses/
Ecommerce data
List of latex symbols
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2022-06-26 04:28:38
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https://codereview.stackexchange.com/questions/78817/nim-game-in-haskell-implementing-optimal-strategy
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# Nim game in Haskell implementing optimal strategy
I was inspired by Stas Kurlin's Nim game to write my own. I'm new to Haskell, and quite unfamiliar with monads, do notation, and -- in general -- functional design patterns.
In the game of nim, two players begin with a number of sized piles, e.g. piles of stones. Each player moves by taking a (non-zero) number of stones from one pile. The winning player is the one who takes the last stone (i.e. the one who makes every pile size identically zero).
In my game, a NimPosition is a Map from Word64s to Word64s, where the keys are distinct pile sizes, and the values are the number of piles with that size.
The user interacts with the game by entering space-separated pile sizes, which are then parsed into a list of Word64s, and these Word64s are converted to a NimPosition using the fromList function.
The goal of this Map implementation is to ensure that each NimPosition has a unique representation without making the user have to think too hard about how to enter a position during play. However, I'm not too Data.Map is necessary; it makes more sense to me now to have a NimPosition be a list of Word64s, and ensure that each NimPosition is unique by having fromList be a sort function.
The function nextMove (which I realize now is not a terribly descriptive name) calculates the optimal move to make from a given NimPosition. In the case that the bitwise-xor (aka nim-sum) of all the pile sizes isn't zero, then the optimal play is the (not necessarily unique) move that makes the nim-sum zero. If the nim-sum is already zero, there is no way to make it zero, so there is no optimal move.
(In this case nextMove reduces the size of the largest pile by one; I don't have any good reason why, except that it probably makes it inconvenient for the human opponent, who must calculate the nim-sum to play optimally, but probably can't calculate the bitwise-xor or a list of large integers as fast as she could a list of smaller integers.)
(See this)
Like I said, I'm unfamiliar with Haskell and design patterns in general. But this is my first Haskell program of any length, but I guess ya gotta start somewhere.
GitHub
import qualified Data.Bits as Bit
import qualified Data.Map as Map
import Data.Word (Word64)
import Data.List
import Data.Char
data NimPosition = NimPosition (Map.Map Word64 Word64)
deriving (Eq)
-- A NimPosition is constructed from a map from Word64 to Word64. The
-- keys correspond to the distinct pile sizes, and the values
-- correspond to the number of piles with that size.
data Player = Human
| Computer
data GameState = Game
{ player :: Player
, position :: NimPosition }
data Bit = Bit Bool
deriving (Eq, Ord)
data Binary = Binary [Bit]
deriving (Eq, Ord)
insertWithCounts :: Word64
-> Map.Map Word64 Word64
-> Map.Map Word64 Word64
-- Insert an Word64 into a map as a key. If that Word64 is already present
-- in the map as a key, then increase the value by 1. If the Word64 is
-- not already present, give it the default value of 1.
insertWithCounts pileSize oldMap =
Map.insertWith (\_ y -> y + 1) pileSize 1 oldMap
fromList :: [Word64] -> NimPosition
-- Construct a NimPosition from a list of Word64, where each Word64 is a
-- pile.
fromList xs = NimPosition (foldr insertWithCounts Map.empty xs)
toList :: NimPosition -> [Word64]
-- Convert a NimPosition into a list of Word64, where each Word64 in the list
-- corresponds to a pile.
toList (NimPosition position) =
let pileSizes = Map.keys position
pileQtys = Map.elems position
pileLists = zipWith replicate (map fromIntegral pileQtys) pileSizes
in foldr1 (++) pileLists
instance Show NimPosition where
show = unwords . map show . toList
instance Show GameState where
show (Game Human position) = "Computer's play....=> " ++ show position ++ "\n"
show (Game Computer position) = ""
toBit 0 = Bit False
toBit _ = Bit True
instance Show Bit where
show (Bit False) = "0"
show (Bit True ) = "1"
toBitList :: Integral a => a -> [Bit]
toBitList 0 = []
toBitList n = let (q, r) = n divMod 2
in (toBit r) : toBitList q
toBinary :: Integral a => a -> Binary
toBinary n = (Binary . toBitList) n
instance Show Binary where
show (Binary bitList) = concat $(map show) . reverse$ bitList
positionSum :: NimPosition -> Word64
-- Compute the bitwise xor of the pile sizes.
positionSum position = foldr1 (Bit.xor) (toList position)
winning :: NimPosition -> Bool
-- According to Bouton's theorem, a position in nim is winning if the
-- bitwise exclusive or of the pile sizes is exactly zero.
winning position = (positionSum position == 0)
losing :: NimPosition -> Bool
losing position = (sum . toList) position == 1
terminal :: NimPosition -> Bool
terminal position = (sum . toList) position == 0
findNumWithLeadingBit :: [Word64] -> Maybe Word64
| maxBinaryLengthIsUnique = lookup maxBinaryLength lengthValueAlist
| otherwise = Nothing
where binaryExpansions = map (show . toBinary) xs
binaryLengths = map length binaryExpansions
lengthValueAlist = zip binaryLengths xs
maxBinaryLength = maximum binaryLengths
numsWithMaxBinaryLength = filter (== maxBinaryLength) binaryLengths
maxBinaryLengthIsUnique = length numsWithMaxBinaryLength == 1
isValidMove :: NimPosition -> NimPosition -> Bool
isValidMove prevPosition nextPosition =
let prevPiles = toList prevPosition
nextPiles = toList nextPosition
pilesNotInPrevPosition = nextPiles \\ prevPiles
pilesNotInNextPosition = prevPiles \\ nextPiles
in case (pilesNotInNextPosition, pilesNotInPrevPosition) of
(originalSize:[],resultantSize:[]) | resultantSize < originalSize -> True
| otherwise -> False
_ -> False
nextMove :: NimPosition -> NimPosition
nextMove prevPosition =
if winning prevPosition then
let prevList = (reverse . toList) prevPosition
nextList = (head prevList - 1) : (tail prevList)
in fromList nextList
else
let prevList = toList prevPosition
Just bigPile -> fromList (newPile:otherPiles)
where otherPiles = delete bigPile prevList
newPile = foldr1 (Bit.xor) otherPiles
where remainingPiles = zipWith delete prevList (repeat prevList)
remainingNimSums = map (foldr1 Bit.xor) remainingPiles
candidateLists = zipWith (:) remainingNimSums remainingPiles
candidateMoves = map fromList candidateLists
possibleMoves = filter (isValidMove prevPosition) candidateMoves
(Nothing, _) -> []
readIntFromString :: String -> (Maybe Word64, String)
let (_, newString) = span (isSpace) string
(intString, remainder) = span (isNumber) newString
numberRead = case null intString of
True -> Nothing
getIntList :: IO [Word64]
getIntList = do
line <- getLine
True -> do
putStrLn "Parse error: can't read list of integers"
getIntList
getNimPosition :: IO NimPosition
getNimPosition = do
intList <- getIntList
return $fromList intList getValidNimPosition :: NimPosition -> IO NimPosition getValidNimPosition oldPosition = do newPosition <- getNimPosition case isValidMove oldPosition newPosition of False -> do putStrLn "Player error: not a valid position" getValidNimPosition oldPosition True -> return newPosition takeTurns :: Maybe GameState -> IO (Maybe GameState) takeTurns Nothing = do putStrLn "Game Over!"; return Nothing takeTurns (Just currentState) = let currentPosition = position currentState in do (putStr . show) currentState case (losing currentPosition) || (terminal currentPosition) of True -> takeTurns Nothing _ -> case player currentState of Computer -> let computersNextMove = nextMove$ position currentState
nextState = currentState { player = Human,
position = computersNextMove}
in takeTurns $Just nextState Human -> do playersNextMove <- getValidNimPosition$ position currentState
let nextState = currentState { player = Computer
, position = playersNextMove} in do
takeTurns $Just nextState data YesNo = Yes | No getYesOrNo :: IO (YesNo) getYesOrNo = do input <- getLine case input of "yes" -> return Yes "y" -> return Yes "no" -> return No "n" -> return No _ -> do putStr "Please enter 'yes' or 'no': "; getYesOrNo introduceGame :: IO () introduceGame = putStrLn "Welcome to Nim! To get started, enter your initial position, e.g. '1 3 5'" main = do introduceGame putStr "Initial position => " startingPosition <- getNimPosition let initialGameState = Just Game { player = Computer , position = startingPosition } in takeTurns initialGameState putStr "Would you like to continue? (y/n): " shouldContinue <- getYesOrNo case shouldContinue of Yes -> main No -> do putStrLn "Goodbye!"; return () • This won't build due to a dependency on Data.List.Util, which I think must be a module the OP wrote. To build, remove that import and change the Show instance for NimPosition, I believe unwords . map show . toList is equivalent. – bisserlis Jan 28 '15 at 0:34 • @bisserlis Not only equivalent, but simpler too. I've edited the code to remove the dependency following your suggestion. (The library Data.List.Utils is in fact provided by MissingH.) – Ted Sperling Jan 28 '15 at 2:45 ## 1 Answer Some ideas: • For Bit and Binary use newtype rather than data to get rid of data's run-time overhead. • Instead of custom Bits you could use the Data.Bits instance of Integer. This would simplify or remove a lot related code. • As you noted, for NimPosition you could either use just a list, or even a multi-set. • For findNumWithLeadingBit function maximumBy seems to be useful. Or perhaps even more simplified, something like (untested) where withLengths = map (id &&& (length . show . toBinary)) xs maxBinaryLength = maximum . map snd$ withLengths
numsWithMaxBinaryLength = filter ((== maxBinaryLength) . snd) withLengths
maxBinaryLengthIsUnique = length numsWithMaxBinaryLength == 1
• Rather than if it's often more readable to use guards, for example:
nextMove prevPosition | winning prevPosition = ...
| otherwise = ...
• Code that tries various options, to eventually find one that matches some criteria, can be often nicely expressed using the [] or Maybe monad using MonadPlus functions. Package monadplus has more useful functions, for example mfromList.
• It's strongly recommended to include types for all top-level functions.
Otherwise nice program! I also like that you meaningfully named variables, this really helps reading the code.
• @peter, so grateful for your comments. I did this project this a year and a half ago when I was new to Haskell, and I would have done so many things differently (e.g., including a cabal file!). I'll definitely take your suggestion on MonadPlus. – Ted Sperling Jul 19 '16 at 3:20
|
2019-07-16 15:55:06
|
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|
http://physics.stackexchange.com/questions/67810/gibbs-paradox-why-should-the-change-in-entropy-be-zero
|
Gibbs Paradox - why should the change in entropy be zero?
The Gibbs paradox deals with the fact that for an ideal gas with $N$ molecules in a volume $V$ seperated by a diaphragm into two subvolumes $V_1,V_2$ with $N_1,N_2$ particles in each subvolume, removing the diaphragm gives a nonzero change in entropy, but the change should be zero.
I don't understand why (conceptually) the change of entropy in this situation is supposed to be zero. Why isn't it positive - after all, removing the diaphragm gives the particles more freedom and thus increases the 'disorder' of the system and with entropy being a measure of this 'disorder' it should too increase. Conversely, if I put more and more diaphragms into the container, I could potentially isolate each particle in its own subvolume and leading the system to be very ordered, so the entropy should be very small.
What is wrong with this way of thinking?
-
The paradox is: with such a big jump in entropy, you would see a significant change in your system - like a sudden temperature drop. Obviously, this doesn't happen, hence the paradox. – gigacyan Jun 12 at 15:57
The entropy change should be zero – and essentially is zero, in the correct theory that takes the indistinguishability into account – because the thin membrane doesn't materially change the system and carries a tiny entropy by itself. The first reason is enough: the removal of the membrane is a reversible process – one may add the membrane back – so the entropy has to be zero. An entropy can't increase during a reversible process because it would decrease when the process is reversed – and that would violate the second law of thermodynamics.
In other words, the self-evident reversibility of the unphysical membrane means that $\delta S = \delta Q/T$ where $\delta Q$ is the heat flowing to the system – but it's clearly zero.
The paradox is removed when the indinguishability of the particles is appreciated. The calculable entropy change is zero, as expected. In some sense, we are implicitly assuming that the molecules are indistinguishable everywhere above. If the molecules carried some passports, they could have a Canadian and American passport in the volume $V_1,V_2$, respectively, which would be a very special state (none of the molecules is abroad) while the number of states would be increased because each molecule may be either in its own country/volume or abroad. This is indeed why the wrong classical calculation claims that the entropy would increase.
However, this prediction may be extracted even if the initial total volume $V_1+V_2$ is actually perfectly mixed before the membrane is added.
-
|
2013-12-20 07:58:00
|
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|
https://yalmip.github.io/_posts/tutorials/2016-09-17-linearprogramming/
|
# Linear programming
Tags:
In this example, we are given two sets of data, called blues and greens. Our goal is to separate these sets using a linear classifier.
blues = randn(2,25);
greens = randn(2,25)+2;
Display it
plot(greens(1,:),greens(2,:),'g*')
hold on
plot(blues(1,:),blues(2,:),'b*')
A linear classifier means we want to find a vector $$a$$ and scalar $$b$$ such that $$a^Tx + b \geq 0$$ for all the green points, and $$a^Tx+b\leq 0$$ for all blue points (a separating hyperplane). By looking at the data, it should be clear that this is impossible. What one then would like to do, is to find a hyperplane which misclassifies as few points as possible. This is typically a very hard combinatorial problem, so we will work with an approximation instead.
As a proxy for misclassification, we introduce positive numbers $$u$$ and $$v$$ and change the classification to $$a^Tx+b\geq 1-u$$ and $$a^Tx+b\leq -(1-v)$$. If both $$u$$ and $$v$$ are small, we should obtain a good separation.
We define the decision variables of interest
a = sdpvar(2,1);
b = sdpvar(1);
We will use one $$u$$ and $$v$$ variable for each point, hence we create two vectors of suitable length. It will be obvious below why we define them as row-vectors.
u = sdpvar(1,25);
v = sdpvar(1,25);
The classification constraints are easily defined by exploiting MATLABs and YALMIPs ability to add scalars and vectors
Constraints = [a'*greens+b >= 1-u, a'*blues+b <= -(1-v), u >= 0, v >= 0]
We want $$u$$ and $$v$$ to be small, in some sense, as that indicates a good classification. A simple choice is to minimize the sum of all elements $$u$$ and $$v$$. However, the problem is ill-conditioned in that form, so we add the constraint that the absolute value of all elements in $$a$$ are smaller than $$1$$.
Objective = sum(u)+sum(v)
Constraints = [Constraints, -1 <= a <= 1];
At last, we are ready to solve the problem
optimize(Constraints,Objective)
The values of the optimal $$a$$ and $$b$$ are obtained using value. To better illustrate the results, we use YALMIPs ability to plot constraint sets to lazily display the separating hyperplane.
x = sdpvar(2,1);
P1 = [-5<=x<=5, value(a)'*x+value(b)>=0];
P2 = [-5<=x<=5, value(a)'*x+value(b)<=0];
clf
plot(P1);hold on
plot(P2);
plot(greens(1,:),greens(2,:),'g*')
plot(blues(1,:),blues(2,:),'b*')
|
2018-04-22 14:27:43
|
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|
http://www.newton.ac.uk/programmes/DDP/seminars/2009110910209.html
|
# DDP
## Seminar
### Hints of the fourth planet around upsilon Andromedae
Baluev, R (Pulkovo Observatory)
Monday 09 November 2009, 10:20-10:40
Satellite
#### Abstract
We analyse the array of 288 recently published new and revised Lick observatory radial velocity (RV) measurements of $\upsilon$ And. The periodogram analysis reveals three RV periodicities of relatively small semi-amplitudes (about 10 m/s), in addition to the variations due to three known Jovian planets. These new periods are about 12 years, 180 and 360 days. The two latter variations cannot be interpreted as planetary signatures because of the dynamical stability argument. These annual variations have to be interpreted as errors in the RV data, which may have instrumental or data reduction nature. The long-period RV variation may allow stable orbital configurations and is consistent with the fourth distant planetary companion. Its orbital period is unconstrained from the upper side (longer periods require higher eccentricities, up to a parabolic orbit), but its minimum mass $m\sin i$ is likely between 0.5 and 3.0 times Jupiter mass. The condition of the dynamical stability limits the set of possible orbits of the fourth planet to the 3/1, 4/1, 5/1, 6/1 mean-motion resonances with planet d or to longer-period elongated orbits with pericenter distance of 5-6 AU (with semi-major axis larger than ~10 AU). We also discuss non-planetary interpretations for the long-term RV variation, which are currently difficult to rule out. Efficient confirmation and verification of this planet candidate can be done by means of, e.g., long-term astrometry and star magnetic activity monitoring.
|
2014-07-28 14:27:21
|
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|
https://socratic.org/questions/how-do-you-graph-y-lnx-1
|
# How do you graph y=lnx-1?
Sep 22, 2016
The graph of $y$ is the standard function $\ln x$ shifted one unit down the $y -$axis. $y$ has a zero at $x = e$
#### Explanation:
$f \left(x\right) = \ln x$ has a vertical asymtote at $x = 0$ and a zero at $x = 1$
In this question $y = f \left(x\right) - 1$ which simply shifts ("transforms") $f \left(x\right)$ one unit down the $y -$ axis.
To find the zero:
$y = \ln x - 1 = 0 \to \ln x = 1$
$x = {e}^{1} = e$
Hence $y$ has a zero at $x = e$
These features can be seen on the graph of $\ln x - 1$ below:
graph{lnx-1 [-4.64, 15.36, -5.65, 4.35]}
|
2020-08-12 06:32:09
|
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|
http://piping-designer.com/index.php/properties/634-engineering-mathematics-science-nomenclature/2005-equivalence-symbols
|
# Equivalence Symbols
Written by Jerry Ratzlaff on . Posted in Nomenclature & Symbols for Engineering, Mathematics, and Science
This is a list of the most common equivalence symbols:
SymbolDefinitionExample
$$=$$ equal to $$5+4=9$$
$$\ne$$ not equal to $$5\ne4$$
$$\equiv$$ identical to $$a \equiv b$$
$$\not\equiv$$ not identical to $$a \not\equiv b$$
$$\sim$$ similar to $$a \sim b$$
$$\approx$$ approximately equal to $$a \approx b$$
$$\cong$$ congruent, equivalent in size and shape $$\triangle ABC \cong \triangle XYZ$$
$$:=$$ is defined to be $$a := \{2, 4, 6, 8 \}\;$$ means $$\;a\;$$ is defined to be set $$\;\{2, 4, 6, 8 \}$$
$$\therefore$$ therefore $$a=b\; \therefore\; b=a$$
$$\because$$ because $$a=b\; \because\; b=a$$
$$>$$ greater than $$5>4$$
$$\gg$$ much greater than $$50000 \gg 4$$
$$<$$ less than $$4<5$$
$$\ll$$ much less than $$4 \ll 50000$$
$$\ge$$ greater than or equal to $$a\ge b$$
$$\le$$ less than or equal to $$a\le b$$
$$\Rightarrow$$ implies if then - $$\; a \Rightarrow b\;$$ means if $$\;a\;$$ is true then $$\;b\;$$ is also true, if $$\;a\;$$ is false then nothing is said about $$\;b$$ $$a = 3 \Rightarrow a3 = 9\;$$ is true, but $$\;a3 = 9 \Rightarrow a = 3\;$$ is in general false since $$\;a\;$$ could be $$\;−3$$
$$\rightarrow$$ same as above same as above
$$\Leftrightarrow$$ if and only if - $$\;a \Leftrightarrow b\;$$ means $$\;a\;$$ is true if $$\;b\;$$ is true and $$\;a\;$$ is false if $$\;b\;$$ is false $$a + 2 = b - 5 \Leftrightarrow a = b - 7$$
$$\leftrightarrow$$ same as above same as above
|
2019-04-19 09:08:05
|
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|
https://isabelle.in.tum.de/repos/isabelle/rev/0f8cb37bcafd?revcount=30
|
author haftmann Tue, 26 May 2009 13:40:49 +0200 changeset 31255 0f8cb37bcafd parent 31254 03a35fbc9dc6 child 31256 cf75908fd3c3
clarified benefit of interpretation
--- a/doc-src/Classes/Thy/Classes.thy Tue May 26 12:31:01 2009 +0200
+++ b/doc-src/Classes/Thy/Classes.thy Tue May 26 13:40:49 2009 +0200
@@ -485,14 +485,23 @@
qed
qed intro_locales
+text {*
+ \noindent This pattern is also helpful to reuse abstract
+ specifications on the \emph{same} type. For example, think of a
+ class @{text preorder}; for type @{typ nat}, there are at least two
+ possible instances: the natural order or the order induced by the
+ divides relation. But only one of these instances can be used for
+ @{command instantiation}; using the locale behind the class @{text
+ preorder}, it is still possible to utilise the same abstract
+ specification again using @{command interpretation}.
+*}
subsection {* Additional subclass relations *}
text {*
- Any @{text "group"} is also a @{text "monoid"}; this
- subclass relation,
- together with a proof of the logical difference:
+ Any @{text "group"} is also a @{text "monoid"}; this can be made
+ explicit by claiming an additional subclass relation, together with
+ a proof of the logical difference:
*}
subclass %quote (in group) monoid
@@ -559,7 +568,7 @@
subsection {* A note on syntax *}
text {*
- As a commodity, class context syntax allows to refer
+ As a convenience, class context syntax allows to refer
to local class operations and their global counterparts
uniformly; type inference resolves ambiguities. For example:
*}
--- a/doc-src/Classes/Thy/document/Classes.tex Tue May 26 12:31:01 2009 +0200
+++ b/doc-src/Classes/Thy/document/Classes.tex Tue May 26 13:40:49 2009 +0200
@@ -922,15 +922,25 @@
%
%
+\begin{isamarkuptext}%
+\noindent This pattern is also helpful to reuse abstract
+ specifications on the \emph{same} type. For example, think of a
+ class \isa{preorder}; for type \isa{nat}, there are at least two
+ possible instances: the natural order or the order induced by the
+ divides relation. But only one of these instances can be used for
+ \hyperlink{command.instantiation}{\mbox{\isa{\isacommand{instantiation}}}}; using the locale behind the class \isa{preorder}, it is still possible to utilise the same abstract
+\end{isamarkuptext}%
+\isamarkuptrue%
+%
}
\isamarkuptrue%
%
\begin{isamarkuptext}%
-Any \isa{group} is also a \isa{monoid}; this
- subclass relation,
- together with a proof of the logical difference:%
+Any \isa{group} is also a \isa{monoid}; this can be made
+ explicit by claiming an additional subclass relation, together with
+ a proof of the logical difference:%
\end{isamarkuptext}%
\isamarkuptrue%
%
@@ -1038,7 +1048,7 @@
\isamarkuptrue%
%
\begin{isamarkuptext}%
-As a commodity, class context syntax allows to refer
+As a convenience, class context syntax allows to refer
to local class operations and their global counterparts
uniformly; type inference resolves ambiguities. For example:%
\end{isamarkuptext}%
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2021-09-22 06:39:15
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https://www.theamplituhedron.com/tools/Nonagon-Formulas-Calculator/
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## Introduction
In geometry, a nonagon is a nine-sided polygon or 9-gon. Calculate its area and perimeter.
# Nonagon Formulas Calculator
## Introduction
In geometry, a nonagon is a nine-sided polygon or 9-gon. Calculate its area and perimeter.
# Description
In geometry, a nonagon is a nine-sided polygon or 9-gon. Calculate its area and perimeter.
$A$, Symbol for Area;
${P}_{}$, Symbol for Perimeter;
${a}_{}$, Symbol for Side;
## Quote from Wikipedia
In geometry, a nonagon (/ˈnɒnəɡɒn/) or enneagon (/ˈɛniəɡɒn/) is a nine-sided polygon or 9-gon. The name "nonagon" is a prefix hybrid formation, from Latin (nonus, "ninth" + gonon), used equivalently, attested already in the 16th century in French nonogone and in English from the 17th century. The name "enneagon" comes from Greek enneagonon (εννεα, "nine" + γωνον (from γωνία = "corner")), and is arguably more correct,[1] though less common than "nonagon". The regular enneagon has Dih9 symmetry, order 18. There are 2 subgroup dihedral symmetries: Dih3 and Dih1, and 3 cyclic group symmetries: Z9, Z3, and Z1. These 6 symmetries can be seen in 6 distinct symmetries on the enneagon. John Conway labels these by a letter and group order.[3] Full symmetry of the regular form is r18 and no symmetry is labeled a1. The dihedral symmetries are divided depending on whether they pass through vertices (d for diagonal) or edges (p for perpendiculars), and i when reflection lines path through both edges and vertices. Cyclic symmetries in the middle column are labeled as g for their central gyration orders. Each subgroup symmetry allows one or more degrees of freedom for irregular forms. Only the g9 subgroup has no degrees of freedom but can seen as directed edges.
## Area
$A=\frac{9}{4}{a}^{2}\mathrm{cot}\left(\frac{{180}^{o}}{9}\right)$
# Output
## Perimeter
$P=9a$
# Output
## References
Figure - 24.1 https://www.redbubble.com/people/keplercat/works/27929051-nonagon-shape-black?p=poster
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2020-03-30 09:03:19
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https://physics.stackexchange.com/questions/688925/why-cant-we-find-exact-position-of-an-electron-heisenberg-uncertainty-principle
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# Why cant we find exact position of an electron-Heisenberg Uncertainty principle?
I am using the book Classical Dynamics of Particles and Systems by STEPHEN T. THORNTON, JERRY B. MARION, page 88, and they say:
"We can conceivably measure the position of an electron by scattering a light photon from the electron. The wave character of the photon precludes an $$\textit{exact}$$ measurement, and we can determine the position of the electron only within some uncertainty $$\Delta x$$ related to the extent (i.e. the wavelength) of the photon."
$$\textbf{Question 1}$$
What exactly do they mean about the $$\textit{wave character of the photon}$$? What characteristic are they referring to?
$$\textbf{Question 2}$$
I guess Q1 would shed light on to this question: Why is the uncertainty related to the wavelength of the photon that is being used to measure it?
I know about the $$\textbf{Heisenberg Uncertainty principle}$$ and I know about $$\Delta p$$ part of the principle and that photons add momentum to the electron per hit. I am wanting to find photons cant give an accurate position of a $$\textit{still}$$ electron at the place of where it got hit by the photon, what happens afterwards is not important.
I would really appreciate any answer that would shed some light onto my problem.
• These are evergreen questions that have been asked many times. You should search the existing questions a bit more carefully.
– Dan
Jan 15 at 21:41
• @Dan this is a slightly different question,, the common question is basically" more precisely the position is known the more uncertain the momentum", but I get that, the real question is why must we use a higher frequency(shorter wavelength) photons to measure an electron or is that only a requirement for the principle? could we use a larger wavelength to find position of the electron? Jan 15 at 21:56
• Jan 15 at 23:09
Imagine a standing wave and a particle (1D case). The wave exerts influence on the electron at its peaks but at its nodes the particle is not acted on. If you were to judge the location of the particle by the force (acceleration) acted on it then in the presence of measurement errors you can only be more certain about where it is not likely to be rather than where it is. That is because around the peak effect the curve is flat (the sinusoid has zero or small derivatives) and the particle can be with the same likelihood in that broad flat region almost anywhere.
In contrast, at the nodes the detection curve is steep (the sinusoid has the largest derivative), so to decide the location more precisely we can have shorter wavelength and by that we can learn the particle location within a wavelength that can be arbitrary small. This will improve accuracy but with a multiplicity of possibilities, the buzzword is "ambiguity", and each possibility has improved SNR and good discrimination against other possibilities but uniqueness is lost.
You cannot discover the exact position of an electron for exactly the same reason you cannot discover an electron's favorite movie. Electrons do not have favorite movies.
• This is seriously not helpful, and in some contexts wrong. An electron can have an arbitrarily exact position. It means that the other part of the HUP has to grow.
– Dan
Jan 16 at 5:23
The author is not making clear the subject by:
The wave character of the photon
Light,classical electromagnetic radiation, described by Maxwell's equations, has a wave character. In contrast the photon is an elementary point particle in the standard model of particle physics and thus has no wavelength. Its energy $$hν$$ is connected with the frequency $$ν$$ of the light wave that a huge number of photons build up, but the concept of wavelength is only in the wavefunction of the photon , i.e. the probability of finding the photon at (x,y,z).
The wavefunction of the photon is given by a solution of a quantized mMxwell equation, thus the connection with the classical light wave frequency.
This link may help in acquiring an intuition of how single photons add up to the classical light.
Single-photon camera recording of photons from a double slit illuminated by very weak laser light. Left to right: single frame, superposition of 200, 1’000, and 500’000 frames.
In the context of the quote, it is the probability of the photon interacting with the electron that gives the HUP uncertainty. To get a probability distribution one has to have a fair number of same energy photons interact with the electron which sits at (x,y,z) and the distribution in space of the reflected photon will have the uncertainty of the probability wave nature. One could not define the (x,y,z) of the electron with an accuracy better than the wave length of the probability distribution.
The HUP does not in itself say that an electron cannot have an exact position. What it reflects is the fact that the probability of finding an electron at a given place is related to the amplitude of its wave function at that place, so for an electron to have a well defined position it must have a wave-function whose amplitude drops off to zero over a very small distance, and that means that it must have a wide spread in momentum space. The result is that the more you constrain the electron's position the more you increase the uncertainty about its momentum.
The reason why we can't pinpoint the position of an electron exactly should be obvious if you consider the fact that the only options we have to measure the position is to observe the results of interactions between the electron and other microscopic particles, and those particles themselves have uncertain positions. If an electron scatters a photon, we can't know exactly where the scattering took place, because it could have been anywhere in the volume of space where the electron's wave function overlapped with the photon's. That volume gets bigger as the photon's associated frequency gets lower. An ultra-low frequency radio wave might have a wavelength of many kilometres, and the wave function associated with a photon of that frequency would have a larger spatial spread than the wave function of a highly energetic gamma ray, say.
The other problem, of course, is that we can only know what the approximate position of the electron was at the point the scattering occurred, since the electron itself will have recoiled from the scattering event and will now be somewhere else.
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2022-10-04 01:29:38
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https://www.gamedev.net/forums/topic/199608-do-you-make-your-own-models/
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• ### Announcements
#### Archived
This topic is now archived and is closed to further replies.
# Do you make your own models?
## Recommended Posts
MessageBox 109
Does anyone(hobbyists) actually build there own 3d models for their games, or do they use existing models you can get off the net?
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yckx 1298
I make my own. The really simple ones I used initially were hand coded, then I picked up Milkshape3d.
yckx
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JTippetts 12949
I make my own, too.
Josh
vertexnormal AT linuxmail DOT org
Check out Golem: Lands of Shadow, an isometrically rendered hack-and-slash inspired equally by Nethack and Diablo.
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krez 443
i just use cubes. if it ever gets far enough to matter i''d get someone else to make the models
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DJSnow 100
i''m using models from public sites for testpurposes
i''m no graphician, and i don''t know one who could take up the work for my private things.
DJSnow
---
this post is manually created and therefore legally valid without a signature
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RPGamer 122
I tend to program in ''layers'' First I will program the engine, then go through and add in eye candy such as 3D Models and such. Way back when I downloaded objects off the net, but now I use Milkshape 3D to model objects, UV Map them with LithUnwrap and texture them using Paintshop Pro. That setup is about 100 dollars, not bad
RPGamer
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psykr 295
I input the floats in binary.
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MessageBox 109
I think I''m going to get Milkshape, I haven''t seen a bad word said about it.
What''s the deal with it anyway, is it free? I went to the site and found a download link, I thought it wasn''t supposed to be free.
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OrangyTang 1298
quote:
Original post by MessageBox
I think I''m going to get Milkshape, I haven''t seen a bad word said about it.
What''s the deal with it anyway, is it free? I went to the site and found a download link, I thought it wasn''t supposed to be free.
Milkshape is pretty good. Its not free but it is pretty darn cheap (especially compared to the other modelers which cost way more). About the only other low cost alternative is Blender (which is free, but has an awful UI and a horrible elitist attitude surrounding it).
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Anim8or is equally as good as milkshape and it is free. I''ve used this to model loads of stuff.
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Nypyren 12061
My artist friend makes the models, I make the program.
He''s freakin good at it, too.
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MessageBox 109
quote:
Original post by pkelly83
Anim8or is equally as good as milkshape and it is free. I''ve used this to model loads of stuff.
Yeah, but you can''t export animations with it.
I think it''s planned for the next version though.
I just don''t like Blender, gave it a chance, but it can be extremely frustrating.
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RonHiler 214
If you''re on a serious budget, Milkshape is okay . What you''ll find eventually though is that it gets to be pretty limiting. The animation support especially is very limited. But at $25, if you''re on a serious budget, it''s the way to go. It''s what I started with. GameSpace, which is what I use now, is a very good modeller/animator, IMO. It is a bit more spendy ($300), but way less than 3DSMax/Maya/TrueSpace, and unlike those packages, GS is geared specifically toward game development. It''s one drawback as far as I''m concerned is it''s native UV mapping interface, which, while doable, is somewhat horrific. Supposedly they are working on it to make it easier/better.
Milkshape is essentially designed to build models one poly at a time (yeah, there are built in primitives and extrude functions and the like, but without the ability to move around vertices in the perspective view, it''s just as time consuming to get them in the right spot as it is to drop down one face at a time). GS is designed to use primitives and extrudes, and does allow you to model right in the perspective view, which, once you get used to it, makes things much faster. Just to give an idea, I spent about two weeks modelling just the legs of my avatar in MS. Then I went to GS, started over, and modelled the entire avatar in 2 days (including learning the interface), and the resulting model is far better than what I had previously. So you can see it''s much more efficient in GS.
Of course, then I hit the texturing part, and it was like hitting a brick wall Hopefully they get that fixed soon. I haven''t yet done animation with the package, but I''ve seen the tutorials, and it looks pretty well done. Plus it supports animation sets (which MS3D doesn''t), which effectively is the reason I left MS3D in the first place.
So, MS3D is a good place to start if you''re low on funds, but eventually you''ll probably find you need something better.
And yes, you should probably do your own models, or have them done. Taking stuff off the web is just asking for a lawsuit Unless it''s specifically freeware *and* without copywrite *and* your project is non-commercial, I wouldn''t use other''s models.
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Dobbs 164
I agree with RonHiler about Milkshape being quite limiting. I used to use it for modelling (I still find it useful for converting between different formats and other little things) but I switched to Wings3D a while ago and haven''t looked back. It''s a dream to work with. It''s also free.
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OrangyTang 1298
quote:
Original post by Dobbs
but I switched to Wings3D a while ago and haven''t looked back. It''s a dream to work with. It''s also free.
Last time I looked, Wings doesn''t support any sort of animation - one of the good things about milkshape is that its about the only cheap modeler that support skeletanal animation. (And can export to a whole bunch of animated formats like md2 as well as its own). I''m still keeping my eye on Wings though..
Milkshape is great for what its intended for - low poly models like game characters, weapons or other items. I wouldn''t try and use it as a level creator though.
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2017-08-17 15:54:54
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http://nxttime.wordpress.com/category/lejos/
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Archives for category: LEJOS
This Christmas holiday I started working on a new robot, called Agilis. This robot should be a very agile and elegantly moving robot. The frame is based on a triangle equipped with holonomic wheels. So you might think, “What’s new, it is like your last robot?”. From the outside this is true, but it gets new and better brains on the inside. Let me tell you what I envision.
Most robots I built went from point A to point B, only then to decide what to do next. Others just drove around avoiding obstacles. This one should be able to do both at the same time. Agilis must be able to perform complex manouvres, like driving in a straight line while rotating around its centre, or like driving an arc while keeping pointed at an arbitrary spot. It should constantly use sensory input to stay on course, or to alter its course if needed. And all this must go fluently, just like a cat walking through the room.
Over the next several posts I will discuss the different aspects of Agilis. This first post deals with the drive system.
## the chassis
Agilis is a three wheeled holonomic platform. This means it can drive in any direction without turning. It can turn around any point, even around its own center. Each wheel is driven by a NXT motor via a gear train that has a 1:2 ratio, the wheels rotate twice as fast as the motors. This makes Agilis a relatively fast robot. The gear train has to be very sturdy to handle the torque of the motors. It also has to be precise to allow for odometry. I used the same setup that I developed for my last robot, Koios the Guard bot.
## From robot speed to motor speed
It is not very easy to control a holonomic robot, it takes some math. I created a kinematic model that does just that. The model takes robot speed as input and gives motor speed as output. Robot speed is expressed as speed in x-direction, y-direction and rotational speed. Motor speed is expressed as encoder ticks per second.
So how does this kinematic model look like? For a single wheel this looks like a function that takes the three robot speeds as input. For the three wheels together it looks like a matrix multiplication that multiplies a robot speed vector {xSpeed,ySpeed,angularSpeed} with a kinematic matrix. The resulting vector containers the speed of each of the three wheels. Let’s take a look at the single wheel function first.
To translate robot speed into motor speed one needs to know some physical aspects of the robot, the wheel and the motor. How big is the wheel, how far is it from the center of the robot, under what angle is it mounted, what is the gear ratio of the gear train and what is the number of encoder ticks per full cycle of the motor? With all this information one can write a formula to calculate motor speed from robot speed. Here is the formula.
motorSpeed =
xSpeed * (cosine(wheelAngle) * nEncoderTicks / ( gearRatio * 2 * PI * wheelRadius) -
ySpeed * (sinus(wheelAngle) * nEncoderTicks / (gearRatio * 2 * PI * wheelRadius) +
angularSpeed * distanceToCenter * nEncoderTicks / (gearRatio * 2 * PI * wheelRadius)
This formula might look daunting at first, but on second glance you might notice that there are a lot of constants in it. If you substitute the constants with their respective values you will end up with a much simpler formula.
motorSpeed = xSpeed * aConstantValue - ySpeed * anotherConstantValue + angularSpeed * yetAnotherConstantValue
This formula is not only much simpler, it is also very efficient to calculate, just three multiplications and two additions. A NXT can do this in no time. But remember, these constants are not the same for all the motors because each of the wheels has a different wheelAngle. But, you could also have wheels of different sizes, or differences in any of the other aspects. This means that you will have a formula for each of the motors, each formula is the same in structure but has its own constants. These constants can be stored in a matrix where each row in the matrix contains the 3 constants belonging to a single wheel. The matrix has a row for each of the wheels. If you then take the speed vector and multiply this with the matrix then all formulas are calculated at once and the result, the motorSpeed, is stored in a new vector. Each row in this vector holds the speed of a single motor. In java this matrix multiplication would look like this:
Matrix motorSpeed = kinematicModel.times(robotSpeed);
Wow, now things look simple at last! This is the beauty of matrix algebra.
The same kinematic model can be used to transform robot acceleration into motor acceleration. I use this to make my robot accelerate very smoothly. (the regulated motor class of Lejos supports regulated acceleration).
## From tacho counter to robot position
To drive a robot this kinematic model works perfect. But I also want to be able to do things the other way around. I want to be able to calculate robot position from encoder values. At first I couldn’t figure this out at all. The math was just too complex for my mind. That is, until I realized that I just needed to use the inverse of the kinematic model.
deltaRobotPose = deltaMotorPosition * inverseKinematicModel
Here deltaMotorPosition is a vector containing the change in encoder value of each of the motors since the previous measurement. The inverseKinematicModel is the kinematic model inverted. And deltaRobotPose is the change in pose (x and y position and heading) of the robot. Looks simple, doesn’t it? The problem is how to calculate the inverse matrix of the kinematic model. I can’t tell you, because I don’t know. But hey, somebody else already programmed this in Java. I just used the inverse method of the Matrix class.
## From the robots coordinates to the worlds coordinates
There is just one more thing to it. The robot can have any heading, this means that x and y coordinates of the robot are not aligned with the x and y coordinates of the world. To be able to steer the robot to a certain position in a room one must be able to convert this location to a location as the robot sees it. The same goes for keeping track of pose. We have seen the formula to calculate change in pose from the wheel encoders. This change however is a change as the robot sees it, not a change in the robots position it the world. The translation from world coordinates to robot coordinates can also be done with a simple matrix multiplication using a rotation matrix. The rotation matrix itself can be calculated from the heading of the robot.
$\begin{bmatrix} cos(heading) & -sin(heading) & 0\\ sin(heading)) & cos(heading) & 0\\ 0& 0 & 1 \end{bmatrix}$
Suppose you want to drive your robot to the left side of the room. The speed matrix in world frame would look like {0, speed, 0}. this can be multiplied with the rotation matrix to get a speed matrix as the robot sees it.
RobotSpeed =worldSpeed * rotationMatrix
If we want to go the other way around, to get the change in pose in world frame we multiply the change in robot frame with the (you guessed it) inverse of the rotation matrix. For rotation matrices the inverse is the same as the transpose of the matrix, the transpose is far more efficient to calculate.
## Wrap up
This really is all there is to driving a robot. To sum it up. You have a kinematic model to translate robot speed into motor speed. You have a rotation matrix to translate things from world coordinates to robot coordinates.
The same goes for odometry. You have the inverse of the kinematic model to translate change in encoder values to change in robot pose expressed in robot coordinates. You have the inverse of the rotation matrix to translate change robot pose in robot coordinates into world coordinates.
The kinematic model is a constant, it has to be calculated only once (unless your robot changes shape). The rotation matrix on the other hand has to be updated every time the heading of he robot changes.
## The implementation
the robot uses lejos as its brains. Lejos has some excellent classes to drive the NXT motors. The regulated motor class that I used is able to rotate a motor at any given speed. This speed is maintained no matter what the conditions are. It also supports setting an acceleration rate. This is very good for my robot, as for most movements the wheel speed of the three motors is different. If all wheels would accelerate equally, then the slower moving motors would reach their target speed sooner than the faster spinning motors. This results in a robot that shivers and shakes during acceleration (or breaking). All this can be avoided by setting an acceleration value for each of the motors. The ratio of the acceleration values must be the same as the ratio between the (difference between current speed and) target speed of each of the motors. If done properly the robot accelerates very smoothly without jerky movements.
Lejos also has a Matrix class that helps to perform matrix algebra. I used this class to store the (inverse) kinematic models and the rotation matrix. I subclassed it to make a Pose Class that can be used together with the matrix class.
To create the kinematic model I developed a Builder class. This class has all kinds of methods to describe the robot, the wheels the motors and the gear train. When you are done describing the robot, the builder class delivers you a kinematic model and an inverse kinematic model.
To drive the robot I made a kind of pilot class. I plan to discuss it in a future post. This pilot accepts the kinematic model in its constructor.
For odometry I made another class, the Odometer. This class uses the inverse kinematic model.
Remember my plan to make a ball balancing robot? Last year I set myself the goal to make a ball balancing robot. I even build the robot. Since then I wondered off my original goal and made a guardbot, Koios, from this platform. Now I am having another shot at making a balancing robot.
Programming a balancing robot is easy in theory. You just need a sensor that tells you how much the robot is tilted, most often people use a gyro for this. I use my IMU for this, so that I do not suffer from gyro drift. The tilt angle is then feeded to a PID-controller that transformes tilt to motor speed. The hard part is to tune the PID controller, it has to translate tilt into just the right amount of motor speed, too little and the robot falls of the ball, too much and the robot goes over the top and falls of on the other side of the ball. Falling of the ball damages the robot. So I had a problem, how to tune the PID controller without damaging the robot?
To be able to tune the PID-controller without damaging the robot I made a special platform. It is a large disk with a small pole in the middle pointing down Due to the pole the disk will always be tilted when lying on the ground, only when it balances perfectly on the pole it is level. Therefore this disk can be used to tune the controller. The robot can ride off the disk, but it doesn’t fall then, it just comes on the floor with one or two wheels.
When I tested this setup I discovered that the disk whas too smooth, the wheels didn’t have enough grip and slipped. To increase the friction I coated the surface of the disk with sillicon rubber, It is the light blue surface you see in the picture. Now I have a very “slick” surface.I only hope it lasts under the forces the NXT motors generate.But for the moment this problem is solved.
But there are other problems. One is the fact that these holonomic wheels make the robot vibrate, this affects the IMU filter, there is still some drift although it stays within certain limits. I do have prototype rotacaster wheels. The manufacturer told me that the production wheels are more round and generate less vibrations. If you are ever going to by these wheels, and they are a lot of fun, I advice you to take the black ones. They have the best grip. Anyway, I will have to tune the IMU as well.
Tuning PID controllers is difficult and very, very time consuming. There is some theory around tuning PID controllers but in the end it is mostly trial and error. Everytime I want to try a new set of parameters I’ll have to modify the program, download it to the brick, run the program and evaluate the results by watching the robot. It is hard to understand what goes wrong when you see the robot ride of the disk and make a run for the door to the staircase.
But not anymore. Kirk, one of the developers of Lejos made a very nice program that allows you to tune a running PID controller during over bluetooth. The tool is still under development so you won’t find it in Lejos 0.9.1 yet. This program is an add-on to the charting logger I often use to evaluate internals of the robot on the PC. So basicly, this program shows me what is going on in my robot and allows me to modify PID parameters on the fly. I think this is a great tool. Below is a screen shot of it.
So, now I have the robot, a test platform and a efficient tuning tool. That must mean immediate succes! Well, to be honest I don´t think so. I´m still not sure if I can get this robot to work as there are problem with weight and inertia as well. The robot weigths 998 grams. This is quite heavy, even for three powerful NXT motors. The robot is quite stiff, but there it still bends a bit under weight. This affects the IMU sensor. And I´m working on other projects as well. So in the end I think there is a bigger chance to fail than to succeed.
To be continued.
Few posts ago I introduced Koios the guardbot. This robot can create a map of its surrounding using range sensors. This time I’ll tell some more about this.
The robot uses the map in the process of decision making. These are the main decisions Koios has to make. Is my current location save? Where can I find a safer spot? Where could an intruder appear? Do I spot an intruder?
One thing to keep in mind when reading this post is that the map Koios creates is not permanent. It will be used as long as the robot stays at the same location. Once it starts traveling the map is thrown away. You might think this is a pity, that you could easily keep the map and keep adding more data to it from other locations. This way one could ultimately create a complete map of the surrounding. This is true. But it also is very difficult to do. The main reason for this is that any movement in the robot will always lead to an uncertainty in the position of the robot. This uncertainty makes it impossible to just add a new scan of the surrounding to the old one. You would have to deal with this uncertainty using statistical methods. This technique is known as SLAM, or Simultanious Location And Mapping. I wanted to keep thing simple this time. Hence no SLAM, no permanent map, no overall image of the surrounding but just a temporary map giving an image of the surrounding as observed from the current location. But still, there is a lot you can do based on this information. All the decisions given above can be made based on a temporary map. Compare it to real life. Even without a map you can safely move around in a strange city as you can recognize roads, pavements, etc. you just cannot find your hotel back.
The map is constructed from data from range sensors (US sensor or NX Dist sensor) with aid of a direction sensor (compass or gyroscope). When constructing the map the robot turns around in place. While turning it takes as much range readings as possible and stores the range for all different directions. When using the map one can query the range for any given direction. More on using the map later. First, let me explain how exactly the range data is stored and why it is stored the way it is.
The range map is not a grid as you might expect. It doesn’t have a value (yes or no object) for each combination of x and y. Instead it stores information per direction. It is something like in a northern direction there is an object about 50 cm away.. The number of directions the map recognizes of course is not just four (north, east, etc). This would be a bit to little to be useful. It is not 360 either, this would take too much memory. This would also be overkill as the range sensors do not have a one degree resolution. The number of directions, I call them segments, that the map stores can be chosen by the user. As a rule of thumb I let the width of a segment be equal to half the width of the range sensors beam. As the US sensor has a beam of about 30 degrees a let a segment be 15 degrees. This devides a full circle into 24 segments.
The range is stored per segment. But one can and will have multiple range measurements per segment. One cannot store all measurements, this would take to much memory. One could store the last measurement only. But then one would lose the information from the other measurements. Therefore I went for another option. I wanted to store the average of all measurements taken within a segment. But to maintain and update the average you need other information as well. As the mean is defined as the sum (of the measurements) divided by the number (of measurements) I decided to store both the sum and the number. This allows me to calculate the mean at all times. I also store the sum of squared measurements. This allows me to calculate the variance in the measurements at all times. The variance tells how big the spread in the measurements is. Later we will see why this is useful information.
To wrap this up. A map consists of segments that are like slices of a pie. For each segment the map can give the number of measurements taken, the average range that was measured and the spread in these measurements.
The resulting map uses just 3 integer values per segment. Given 24 segments one needs 72 bytes of data to store a complete image of the surrounding. The NXT can easily handle this. For comparison, a grid map of 4 by 4 meters and a grid size of 10 cm is more or less equivalent to a range map like this. But it would require at least 1600 elements to store its information.
If one would draw the resulting map it would look like a radar screen. The robot would be in the center of the screen. The objects would be around this center. The bigger the object the bigger the reflection on the screen. The further away the object, the further it is from the center in the image. As a matter of fact the range map I build does have methods for displaying map data.
To transform map data to screen data one has to take the following steps:
1. translate segment to angle
2. translate angle to x and y fractions using x=cos(angle) and y=sin(angle)
3. multiply x and y by average range. This gives the distance from robot to the object in x and y direction
4. scale the distance to fit on the screen by multiplying by 32/max range
5. rotate to align robot coordinates to screen coordinates. In my case the poitive x axis of the robot goes from the center of the brick to the motor ports. The positive y axis goes from the center to the left side of the robot. In respect to the screen the x and y axis are swapped as well as the sign of these axis. The resulting rotation is x_screen=-y_robot Y_screen=-x_robot
To use the map one has to translate range data into information that supports a decision. Sometimes this is easy, more often this is quite complicated. Let me give some examples, starting with an easy one and going to more complex examples step by step.
Suppose Koios, who’s goal in life is to find and scare off any intruder in my house, hasn’t seen any intruders for a ling time. It then wants to go to another spot, maybe it has more luck over there to find an intruder. This new spot should be as far away from the current spot as possible. But when traveling to the new spot it does not want to collide with any object in the surrounding. Therefore it uses the map to find the direction in which it can travel as far as possible without hitting an object. It does so by finding the segment that has the highest range value. When this segment is found it will rotate towards that direction and travel the distance corresponding with the range minus a safety margin.
Once arrived at the new location Koios has to make a harder decision, is the current location safe enough to stay and stand guard or does Koios need to find a safer location. I have decided beforehand that a safe location is a secluded location. A location where Koios has objects around him that protect him from people walking over him. To make this decision Koios creates a new map of the surrounding and calculates a safety indication from the number of objects that are close by. If this is large enough Koios regards the spot a safe spot and stays there. If, the current location is not safe enough Koios needs to find a safer spot. It does so by calculating the safety indication of all spots on the map and then to go to the safest spot it could find.
The hardest decision to make is in the process of intruder detection. Is an object detected by the range sensors an intruder or part of the surrounding? This decision is simple at first glance. Any object that is not on the map already must be an intruder. In other words, if the current range is shorter than the range for that direction on the map then there must be an intruder in that direction. But what if the difference between these two ranges is small. It then could as well be caused by some variance in sensor readings as by an intruder. It is here that the variance, or spread, in measurements that I mentioned earlier comes in handy. Statistics say that the square root of variance is called standard deviation. From the mean and the standard deviation one can calculate the likeliness of a range belonging to a new object (intruder) or to the surrounding. If the measured range is smaller than the average range on the map minus two times the standard deviation then there is a 97.5% chance that this object is an intruder.
You can see that none of these decisions need a permanent map. They all can be made using just an actual image of the current surrounding. It therefor is a good decision not to maintain a permanent map and to make the program over complicated.
To conclude. Mapping does not have to be very difficult if one doesn’t need a permanent image of the surrounding. The kind of decisions you want to make dictate if you can do with temporary maps. Also, a map does not have to be very large when choosing a map model wisely.
For those of you that are interested in the code for the range map I provide it below. It is for Lejos and not documented in any way. It therefor will be hard to use straight away. But maybe it can still help you one way or another. The methods that are involved in displaying the map use vector math as this makes rotating and scaling easier. The vector library itself is open source and can be found on the Internet It is called vecmath.
package nl.totan.robot;
import javax.microedition.lcdui.Graphics; import lejos.nxt.Button; import lejos.nxt.LCD; import nl.totan.sensors.INS; import nl.totan.vecmath.Matrix3f; import nl.totan.vecmath.Vector3f; public class RangeMap { int segments; double angle; int depth; int[] sum; int[] n; int[] sumsqr; Vector3f v=new Vector3f(); Vector3f v2=new Vector3f(); Vector3f shift=new Vector3f(50,32,0); INS dcm = null; float scale; Graphics plotter=new Graphics(); private Matrix3f rotate = new Matrix3f(0,-1,0, -1,0,0, 0,0,1); public RangeMap(int segments, int depth){ this.segments=segments; this.depth=depth; angle=2.0*Math.PI/segments; scale=32.0f/depth; sum=new int[segments]; n=new int[segments]; sumsqr=new int[segments]; clearMap(); } public RangeMap(int segments, int depth, INS dcm){ this(segments, depth); this.dcm=dcm; } public void clearMap() { for (int a=0;adepth) range=depth; update(toIndex(currentAngle),range); } public boolean isNew(double currentAngle, double range) { if (range==Double.NaN || range>;depth) return false; int a=toIndex(currentAngle); LCD.clear(); LCD.drawString("Range: " +range, 0, 0); LCD.drawString("Mean : " +getMean(a), 0, 1); LCD.drawString("SDDEV: " +Math.sqrt(getVariance(a)), 0, 2); LCD.drawString("N : " +getN(a), 0, 4); LCD.drawString("DIF : " +(range-getMean(a)-2.0f * Math.sqrt(getVariance(a))), 0, 5); //Button.ENTER.waitForPressAndRelease(); if (range<;getMean(a)-2.0f * Math.sqrt(getVariance(a))) return true; update(a, range); return false; } protected void drawDot( int a, int d) { v.x=(float)(Math.cos(toAngle(a))*d); v.y=(float)(Math.sin(toAngle(a))*d); v2.x=(float)(Math.cos(toAngle(a+1))*d); v2.y=(float)(Math.sin(toAngle(a+1))*d); toScreen(v); toScreen(v2); plotter.drawLine((int)v.x, (int)v.y,(int)v2.x, (int)v2.y); } public void drawMap() { for (int a=0;a<;segments;a++) { drawDot(a,(int)getMean(a)); } if (dcm != null) { //draw north v.x=0; v.y=0; v2.y=0; v2.x=depth; toScreen(v); toScreen(v2); plotter.drawLine((int)v.x, (int)v.y,(int)v2.x, (int)v2.y); } } public RangeMap getDifference(RangeMap old) { RangeMap dif=new RangeMap(segments, depth); double maxDif=10; double myRange, oldRange; boolean isNew; for (int a=0;a<;segments;a++) { myRange=getMean(a); isNew=true; for (int aa=a-1;aa<;=a+1;aa++){ oldRange=old.getMean((aa+segments) % segments); if (oldRange<; myRange+maxDif) { isNew=false; } if (isNew) { dif.sum[a]=sum[a]; dif.n[a]=n[a]; dif.sumsqr[a]=sumsqr[a]; } } } return dif; } public double getProtectionLevel(int a, int dist, int margin) { double level=0; double dist2; double dif; double sin_a=Math.sin(toAngle(a))*dist; double cos_a=Math.cos(toAngle(a))*dist; for (int aa=0;aa0) level+= 0.5-Math.atan(140*dif/depth-4)/3; } return level; } public void drawMarker(int a, int d) { v.x=(float)(Math.cos(toAngle(a))*d); v.y=(float) (Math.sin(toAngle(a))*d); toScreen(v); plotter.drawArc((int)v.x,(int)v.y,4,4,0,360); } public void drawRadius(double angle) { v.x=(float)(Math.cos(angle)*depth); v.y=(float)(Math.sin(angle)*depth); v2.x=0; v2.y=0; toScreen(v); toScreen(v2); plotter.drawLine((int)v.x, (int)v.y,(int)v2.x, (int)v2.y); } void toScreen(Vector3f vec) { if (dcm != null) dcm.transformB(vec); rotate.transform(vec); vec.scale(scale); vec.add(shift); } }
I have included a compass into my INS filter. It now is drift-free and accurate over all three axis. It also is very robust to magnetic disturbances. The compass itself is not. It gives me great pleasure to see the first results.
Tuning the filter is difficult though. I have used the NXJChartingLogger that will be part of Lejos 0.9.1 a lot. The filter provides all kinds of output that is displayed real time on the pc. Different parameters are logically grouped into different graphs. The graphs provide information on the state of the filter and thus help in tuning.
I have also included a method to introduce errors in the sensor data. This enables me to examine the performance of the filter.
As a last thing I have made the filter calculate the initial state of the filter. With this the filter settles accurately (<.5degrees) within half a second.
The performance dropped to 97 Hertz with three sensors attached. But I haven't optimized the compass code yet.
In later posts I'll demonstrate the performance of the filter.
By request I will publish the Lejos software for the dIMU sensor.
The software contains of drivers for the Dexter Industries IMU sensor, programs to calibrate the sensor and the IMU filter that I wrote about on this blog before. The filter can be used for other IMU sensors as well. Also included is the sample program that utilizes this filter. It is the very same program I used in the video’s published in a previous post. There is no formal support and no warranty. If you are going to use it you will have to rely on your own wit, the javadoc and on this blog.
# Using the IMU drivers
The dIMU consists of two sensors, a gyroscope and a accelerometer, each has it’s own driver. The gyroscope driver is called L3G4200D and the driver for the accelerometer is MMA7455L. (I use the technical names of the sensors a driver names.) On top of these drivers I made user interfaces that allowes you to examine, configure and calibrate the sensors. The user interfaces are called L3G4200D_E and MMA7455L_E respectively. You can use these programs as driver as well. It gives your programs access to the additional functionality but it needs the NXT screen and might result in larger programs. There is a sample program included that gives access to the user interfaces, it is called testDIMU.
This is how you enable the drivers in your code,
SensorPort.S4.i2cEnable(I2CPort.HIGH_SPEED);
MMA7455L accel = new MMA7455L(SensorPort.S4);
L3G4200D gyro = new L3G4200D(SensorPort.S4);
The first line instructs Lejos to use high speed I2C. The sensors support this.
This is how you get data (rate, acceleration and tilt) from the sensors.
float[] rate = new float[3];
gyro.fetchAllRate(rate);
float[] accel = new float[3];
accel.fetchAllAccel(accel);
float[] tilt = new float[3];
accel.fetchAllTilt(tilt);
As you can see the drivers return data from all three axis is one call. If you just need data from one axis you can get it from the arrays. The order is X, Y, Z. The gyro returns degrees per second by default. The accelerometer returns Milli-G for acceleration and Degrees for tilt, also by default. If you want to use other units in your programs you can change the default values like this.
gyro.setRateUnit(RateUnits.RPS);
accel.setAccelUnit(AccelUnits.MS2);
This changes the default units to radians per second, meter per second^2 and radians respectively. Other units are available, check the javaDoc. The default unit can be overridden per data request by specifying the desired unit as second parameter in the FetchAll… methods.
# Configuring the sensors
The gyro can be configured for dynamic range and sample rate using the setRange and setSampleRate methods. As a rule one should select the lowest value that your application allows for. This gives data of best possible quality.
The accelerometer cannot be configured. I found this of little use.
# Calibrating the sensors
The gyro of my dIMU doesn’t really need calibrating. however there is the possibility to do so. Calibration is started b calling gyro.calculateOffset(). During calibration the sensor should remain motionless. Calibration settings of the gyro are not stored, so they are lost when your program terminates. (Storing calibration settings of gyro sensors is of no use as the calibration values depend on environmental factors and are not stable over time.)
The accelerometer needs calibration. The user interface driver provides functionality to calibrate the sensor and to store the calibration settings. The (base) driver looks for stored calibration settings upon initialization and loads these automatically when they are available. Calibration settings of the accelerometer are stable over time so you’ll need to do this just once. Each of the three axes has to be calibrated separately. To calibrate an axis one has to point it straight up first and hold still while the calibration routine collects data samples. Then the axis has to be pointed straight down and held still for some time. Follow the on screen instructions and do not forget to save the settings after calibration.
# Using the IMU filter
The IMU filter can be used with any three-axis gyro and any three-axis accelerometer as long as their drivers implement the RataData and TiltData interfaces. This is how you initialise the filter
NLCFilter attitude = new NLCFilter(gyro, accel);
attitude.start();
The two parameters to the filter constructor are the gyro driver and accelerometer driver. One could leave out the accelerometer, the filter will work but values will drift over time. The second line of code starts the filter. The filter needs 2 to 5 seconds to settle at start up, therefore you need to keep the sensor motionless and more or less level for a few seconds. You can find out if the filter is ready settling with the Initializing() method.
The IMU filter keeps track of the attitude, or pose, of your sensor/robot. You can query the roll, pitch and yaw angles this way
attitude.setTiltUnit(TiltUnits.RADIANS);
float roll=attitude.getRoll();
float pitch=attitude.getPitch();
float yaw=attitude.getYaw();
or
float[] tilt = new float[3];
attitude.fetchAllTilt(tilt);
By default these methods return angles in radians. You can change this by setting a different unit with the setTiltUnit() method.
You can also use the filter to transform data from a body frame to a world frame. This is useful if another sensor returns data that needs to be corrected for the robots current attitude. the next example transforms a distance returned by a UltraSonic sensor to world coordinates. The example assumes the us and IMU sensors are aligned and that the US sensor measures along the X-axis.
Matrix usBody=new Matrix(1,3);
Matrix usWorld=null;
us = new UltrasonicSensor(SensorPort.S1);
usBody.set(0,0,us.getDistance());
usWorld=attitude.transformToWorld(usBody);
The matrix usWorld now contains the distance from sensor to the detected object over the X, Y and Z axis.
# Configuring and tuning the IMU filter
By default the IMU filter updates as often as possible. It’s update frequency is over 100 Hertz. To free computer resources one can lower the update frequency by using the setFrequency() method. The filter will try to match the specified frequency. A parameter value of 0 will run the filter at maximum speed.
The filter can be tuned to increase the quality of its output. I advise you not to tune the filter until you are familiar with it and understand its inner workings. Tuning consists of altering the P and I values of it’s internal PI controller. The I value takes care of gyro drift cancellation and the P value controls how fast attitude is corrected by use of tilt data from the accelerometer. The values can be modified by using the setKp() and setKi() methods.
There are two ways the filter can assist you in tuning. It keeps track of the integral of absolute errors, or absI. This is a measure of the total error of the filter over time. The smaller the error (given a fixed period) the better the filter performs. /* The filter also allows you to send data over bluetooth to the pc for examination. For this one has to use the NXTChartingLogger on the pc that is part of the Lejos distribution. You instruct the filter to send its state to the pc by supplying a NXTDataLogger object with the setDataLogger() method. */
# Running the demo program
The demo program is called testIMU. At startup of this program the sensor must be horizontal and motionless. The sensor is assumed to be aligned ith the NXT brick with the sensor plug facing to the same direction as the sensor ports. Once you see the wire frame you can start moving the sensor.The demo has four display modes:
• Wire frame. Here it shows a wire frame of the sensor on the NXT screen
• Rotation matrix. The screen will show the content of the rotation matrix. In this matrix the current attitude is stored. The matrix is also used to convert body coordinates to world coordinates by matrix multiplication..
• Roll, Pitch, Yaw. The screen shows the Roll, Pitch, Yaw angles of the sensor.
• Update speed. The screen shows the actual update speed of the filter.
You can browse through the display modes by using the arrow keys. The enter key resets the filter. The clip below shows the demo program in action in wire frame mode.
Here a quick post of some graphs that show the effect of the filter I use for my IMU.
You might have seen a previous posts where I show you that my sensor is capable of detecting a grain of sugar under the NXT. If you haven’t seen it, check the post and video here. Few months ago I changed from robotC to Lejos. And now I have rewritten the sensor drivers and the filter in Java.
The Lejos developers are currently working on a very nice logging feature that allows users to display data from the NXT real time on the pc. I got hold of the beta code and tested it without any problems. I used the NXTDataLogger (this is the name of the Java class) to made the intrinsics of the IMU filter visible.
The IMU sensor combines a 3-axis gyroscope and a 3-axis accelerometer. The filter reads the output from both sensors, combines there signals in a smart way and provides stable information about the orientation (yaw, pitch and roll) of the robot.
An accelerometer can provide tilt data (pitch and roll) as can be seen in the first graph. This sensor however has two serious drawbacks. First it is quite noisy, that’s why the graph lines seems so hairy. Second, it does not distinguish tilt from acceleration. So, the output from this sensor can have different causes. This is why you cannot make a balancing robot with just an accelerometer.
A gyroscope is far less noisy, that is why the second graph shows smooth lines. It is also not affected by acceleration. However also this sensor has its particularities. First, it doesn’t measure tilt, but it measures rate of turn. This can only be translated into tilt if the starting condition is known. To get the tilt at any time you have to integrate all the readings and the starting condition. In the process small errors are introduced, in the long run they add up to la large error. The green line in the graph shows this effect. At about 42 seconds the sensor rotates faster than its maximum range (>2000 degrees/second), it then gives faulty readings, these are integrated in the calculated tilt. As a result the line ends higher than it started, even though the sensor was turned back to its original position. The second effect that makes a gyro hard to use in long runs is called drift. Due to temperature changes or voltage drops the base level of a gyroscope changes. This means that after some time the gyro seems to be turning slowly when it is still being stationary. This effect is well visible in the blue line. This goes up slowly. This effect can not be eliminated by calibration, unless you are able to calibrate the sensor along the run.
The filter is like a PI-controller. It uses the data from the gyroscope as the basis of it’s output. The lines in the third graph, that shows the output of the filter, are smooth because of this. It uses the data from the accelerometer to correct the output from any errors that have been build up. But it does so slowly in order to keep the noise out of the output signal. The P-value of the PI controller corrects for errors in the gyro signal. It also makes the filter usefull when starting conditions are unknown. The filter also sums past errors to get an I-value, this value is used to correct for drift in the gyro data. The result is a graph with smooth drift-free lines.
Two final notes. First, the green line (the yaw-line) is not drift-free. This is because an accelerometer cannot provide information of orientation in the XY-plane. You need a compass sensor to provide this information. Second, the range is expressed in cosine of the angle, so 1 corresponds to zero degrees, 0 corresponds to 90 degrees.
Here is a short update of my works.
I’m doing two projects at the same time.
First, there is Sidbot. It waits till I master Java threads.
Second, I’m building a holonomic or Killough pilot in Lejos. This project hangs on me not knowing how far the Robot has travelled. This info is needed for the pilot to work with a navigator.
Actually, my main project now is learning java. This goes well but there us a lot to it.
Few weeks ago I ordered two more BlinkM’s. These are I2C driven all color led’s. I wrote a driver to address these led’s. The led’s are now mounted on each corner of Sidbot. So Sidbot can shine all colors to all Sides of it’s triangular body. Each led is driven individually so each one can have it’s own color. I made a nice flashlight show to test the driver.
I finished drivers for my IMU too. The filter to fuse the signals is also finished but it can’t run in a separate thread yet.
I also have been on holidays and busy with work. But these matters don’t concern this blog.
It has been sometime since you saw a post from me. The main reason is that I am really busy with work. The second reason is that I decided to use the LEJOS environment for my current project. I did not have any experience with LEJOS and Java, so I had to dive deep into the matter.
LEJOS allows you to program in the Java language on the NXT. It has some advantages over robotC that I have been using the last two years. I won’t list all the differences between the two languages. For me the higher I2C speed and object orientation were important factors.
Java proved to have a steep learning curve. It took me some time to get the first results. The main reason for this was not the language itself but the IDE. I am using Netbeans to write my programs. Netbeans uses ANT to compile the programs. ANT uses the classes provided with LEJOS. All these components have to work together. And when they don’t it is hard to find out why for a newbe like me. At one point I experienced lots of red lines in my program, indicating errors, but still the program compiled just fine. It turned out that ANT did know where to find the LEJOS classes but Netbeans didn’t.
Slowly I’m getting to grips with Java and the environment. As a first project I decided to write an improved interface to the Mindsensors accelerometer as the existing interface does not allow to set the sensitivity of the sensor or to calibrate it. I also want my sensors to return SI values, I rather have m/s^2 than milli-g for acceleration, I rather have radians than a number between -127 and 128 for tilt. The interface is no jet finished but I do not feel lost anymore when writing a new method to the interface.
After I finish this little side-project I will rewrite the interface to my IMU and the component filter. Only then I can really tell whether my switch to LEJOS has payed of.
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2013-05-24 08:50:40
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https://aitopics.org/mlt?cdid=arxivorg%3A6FB07A40&dimension=concept-tags
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to
### Exponentiated Gradient Exploration for Active Learning
Active learning strategies respond to the costly labelling task in a supervised classification by selecting the most useful unlabelled examples in training a predictive model. Many conventional active learning algorithms focus on refining the decision boundary, rather than exploring new regions that can be more informative. In this setting, we propose a sequential algorithm named EG-Active that can improve any Active learning algorithm by an optimal random exploration. Experimental results show a statistically significant and appreciable improvement in the performance of our new approach over the existing active feedback methods.
### UCB Exploration via Q-Ensembles
We show how an ensemble of $Q^*$-functions can be leveraged for more effective exploration in deep reinforcement learning. We build on well established algorithms from the bandit setting, and adapt them to the $Q$-learning setting. We propose an exploration strategy based on upper-confidence bounds (UCB). Our experiments show significant gains on the Atari benchmark.
### Active Exploration for Learning Symbolic Representations
We introduce an online active exploration algorithm for data-efficiently learning an abstract symbolic model of an environment. Our algorithm is divided into two parts: the first part quickly generates an intermediate Bayesian symbolic model from the data that the agent has collected so far, which the agent can then use along with the second part to guide its future exploration towards regions of the state space that the model is uncertain about. We show that our algorithm outperforms random and greedy exploration policies on two different computer game domains. The first domain is an Asteroids-inspired game with complex dynamics but basic logical structure. The second is the Treasure Game, with simpler dynamics but more complex logical structure.
### Active Exploration in Dynamic Environments
Many real-valued connectionist approaches to learning control realize exploration by randomness inaction selection. This might be disadvantageous when costs are assigned to "negative experiences" . The basic idea presented in this paper is to make an agent explore unknown regions in a more directed manner. This is achieved by a so-called competence map, which is trained to predict the controller's accuracy, and is used for guiding exploration. Based on this, a bistable system enables smoothly switching attention between two behaviors - exploration and exploitation - depending on expected costsand knowledge gain. The appropriateness of this method is demonstrated by a simple robot navigation task.
### Benchmarking Bonus-Based Exploration Methods on the Arcade Learning Environment
This paper provides an empirical evaluation of recently developed exploration algorithms within the Arcade Learning Environment (ALE). We study the use of different reward bonuses that incentives exploration in reinforcement learning. We do so by fixing the learning algorithm used and focusing only on the impact of the different exploration bonuses in the agent's performance. We use Rainbow, the state-of-the-art algorithm for value-based agents, and focus on some of the bonuses proposed in the last few years. We consider the impact these algorithms have on performance within the popular game Montezuma's Revenge which has gathered a lot of interest from the exploration community, across the the set of seven games identified by Bellemare et al. (2016) as challenging for exploration, and easier games where exploration is not an issue. We find that, in our setting, recently developed bonuses do not provide significantly improved performance on Montezuma's Revenge or hard exploration games. We also find that existing bonus-based methods may negatively impact performance on games in which exploration is not an issue and may even perform worse than $\epsilon$-greedy exploration.
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2020-08-12 17:51:34
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https://ai.stackexchange.com/tags/convolution/hot
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# Tag Info
13
3D CNN's are used when you want to extract features in 3 Dimensions or establish a relationship between 3 dimensions. Essentially its the same as 2D convolutions but the kernel movement is now 3-Dimensional causing a better capture of dependencies within the 3 dimensions and a difference in output dimensions post convolution. The kernel on convolution ...
7
Short answer Theoretically, convolutional neural networks (CNNs) can either perform the cross-correlation or convolution: it does not really matter whether they perform the cross-correlation or convolution because the kernels are learnable, so they can adapt to the cross-correlation or convolution given the data, although, in the typical diagrams, CNNs are ...
5
3D convolutions should when you want to extract spatial features from your input on three dimensions. For Computer Vision, they are typically used on volumetric images, which are 3D. Some examples are classifying 3D rendered images and medical image segmentation
4
What are the parameters in a convolutional layer? The (learnable) parameters of a convolutional layer are the elements of the kernels (or filters) and biases (if you decide to have them). There are 1d, 2d and 3d convolutions. The most common are 2d convolutions, which are the ones people usually refer to, so I will mainly focus on this case. 2d ...
4
For a 3 channel image (RGB), each filter in a convolutional layer computes a feature map which is essentially a single channel image. Typically, 2D convolutional filters are used for multichannel images. This can be a single filter applied to each layer or a seperate filter per layer. These filters are looking for features which are independent of the color,...
4
You are partially correct. On CNNs the output shape per layer is defined by the amount of filters used, and the application of the filters (dilation, stride, padding, etc.). CNNs shapes In your example, your input is 30 x 30 x 3. Assuming stride of 1, no padding, and no dilation on the filter, you will get a spatial shape equal to your input, that is ...
4
About the images inside the CNN layers: I really recommend this article since there is no one short answer to this question and it probably will be better to experiment with it. About the RGB input images: When needed to train on RGB pictures it is not advised to split the RGB channels, you can think of it by trying to identify a fictional cat with red ears,...
4
No, nothing really prevents the weights from being different. In practice though they end up almost always different because it makes the model more expressive (i.e. more powerful), so gradient descent learns to do that. If a model has $n$ features, but 2 of them are the same, then the model effectively has $n-1$ features, which is a less expressive model ...
3
Am I right in thinking that because there are only newImageX * newImageY patterns in the 32 x 32 image, that the maximum amount of filters should be newImageX * newImageY, and any more would be redundant? Your assumption is wrong. If you have a $32 \times 32$ images (so consider only grayscale images), then you have $256^{32 \times 32}$ possible patterns (i....
3
For a standard convolution layer, the weight matrix will have a shape of (out_channels, in_channels, kernel_sizes*) in addition you will need a vector of shape [out_channels] for biases. For your specific case, 2d, your weight matrix will have a shape of (out_channels, in_channels, kernel_size[0], kernel_size[1]). Now if we plugin the numbers: out_channels =...
3
I have had similar thoughts about neural networks before. Convolution layers are layers of two dimensional nodes effectively passing the spacial data so why don't we use two dimensional hidden layers to receive information out of them. I'm sure someone has used this type of implementation before. I believe the papers bellow are using this. Part of the ...
3
Usually, you need to ensure that your convolutions are causal, meaning that there is no information leakage from the future into the past. You could start by looking at this paper, which compares Temporal Convolutional Networks (TCN) with vanilla RNNs models.
3
I'm going to post another guess to this question - it won't be a complete answer, but hopefully it'll provide some direction towards finding a more legitimate answer. The feed-forward networks as suggested by Vaswani are very reminiscent of the sparse autoencoders. Where the input / output dimensions are much greater than the hidden input dimension. If you ...
3
I haven't seen it as you describe and I don't think it would be much useful. Pooling layers are being gradually phased out of networks, because they don't seem to be that useful anymore. With the emergence of more and more conv-only architectures, I don't see that likely.
3
I don't think that to understand convolution you need to dig into the nested code of huge libraries, since the code becomes quickly really hard to understand and convoluted (ba dum tsss!). Joking apart, in PyTorch Conv2d is a layer that applies another low level function, conv2d, written in c++. Luckily enough, the guys from PyTorch wrote the general idea ...
3
The point is that in the expansive path you have two forms of information: the information from the contracting path, which includes all high-level features extracted from the original image. the information from the skip-connections, which copy a cropped version of the feature maps in the contracting path. Because, as we go forward through the expansive ...
3
What happens to the size of output feature map in case of full convolution? It increases. First one is valid padding: the blue square is not padded, so the green square is smaller. Third one is same padding: the blue square is padded just enough so that the green square is the same size. Fourth one is full padding: the blue square is padded as much as ...
2
If you have a $h_i \times w_i \times d_i$ input, where $h_i, w_i$ and $d_i$ respectively refer to the height, width and depth of the input, then we usually apply $m$ $h_k \times w_k \times d_i$ kernels (or filters) to this input (with the appropriate stride and padding), where $m$ is usually a hyper-parameter. So, after the application of $m$ kernels, you ...
2
They are not the same thing. asymmetric convolutions work by taking the x and y axes of the image separately. For example performing a convolution with an $(n \times 1)$ kernel before one with a $(1 \times n)$ kernel. On the other-hand depth-wise separable convolutions separate the spatial and channel components of a 2D convolution. It will first ...
2
1) The math is the exact same, so from an optimization or mathematical perspective there is no difference 2) Here are my guesses to a possible answer. Habit: People may just call one over the other out of habit Generality: Across frameworks a 1d convolution op would work, while Dense of FC may need adjustments to work on the temporal axis Parallel ...
2
To show how the convolution (in the context of CNNs) can be viewed as matrix-vector multiplication, let's suppose that we want to apply a $3 \times 3$ kernel to a $4 \times 4$ input, with no padding and with unit stride. Here's an illustration of this convolutional layer (where, in blue, we have the input, in dark blue, the kernel, and, in green, the feature ...
2
Read on Fully Convolutional Networks (FCN). There is a lot of papers on the subject, first was "Fully Convolutional Networks for Semantic Segmentation" by Long. The idea is quite close to what you describe - preserve spatial locality in the layers. In FCN there is no fully connected layer. Instead there is average pooling on top of last low-resolution/high-...
2
Short answer is no. You can't use a model trained for one task to predict on a totally different task. Even if the second task was another image classification task, the CNN would have to be fine tuned for the new data to work. A couple of things to note... 1) CNNs are good for images due to their nature. It isn't necessary that they'd be good for any 2-...
2
In most modern neural network frameworks, the update rules for training can be selectively applied to some parameters and not others. How to do that is dependent on the framework. Some will have the concept of "freezing" a layer, preventing parameters in it being updated. Keras does this for example. Others will do the opposite and expect you to provide a ...
2
You can use CNN for time-series data. The Convolutional Recurrent Neural Network (RCNN) is one of the examples. Convolutional layers basically extract features from images. It is not related to time-series data processing. Some CNNs (such as in ResNet, Highway Networks, and DenseNet) use some recurrent concepts to improve their prediction, but they all are ...
2
Yes this looks a lot like overfitting. The clue is in the low and slowly decreasing training loss compared to the large increases in validation loss. One simple fix would be to stop training around epoch 50, taking the best cross validation result to select the most general network at that point. However, anything that works to improve stable generalisation ...
2
You can also think of a convolutional neural network (CNN) as an encoder, i.e. a neural network that learns a smaller representation of the input, which then acts as the feature vector (input) to a fully connected network (or another neural network). In fact, there are CNNs that can be thought of as auto-encoders (i.e. an encoder followed by a decoder): for ...
2
Mathematically, the convolution is an operation that takes two functions, $f$ and $g$, and produces a third function, $h$. Concisely, we can denote the convolution operation as follows $$f \circledast g = h$$ In the context of computer vision and, in particular, image processing, the convolution is widely used to apply a so-called kernel (aka filter) to an ...
2
It takes a little bit of time to fully understand the 2D convolution/cross-correlation and to relate it to the usual diagrams of the convolution operation, so, before addressing your questions, let me first try to break the definition of the 2D cross-correlation down, from the left to right. S(i,j) =(K*I)(i,j) = \sum_m \sum_n I(i+m, j+n)K(m,n) \label{1}\...
Only top voted, non community-wiki answers of a minimum length are eligible
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2021-08-04 06:26:03
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https://proofwiki.org/wiki/Characteristic_of_Field_by_Annihilator/Characteristic_Zero
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# Characteristic of Field by Annihilator/Characteristic Zero
## Theorem
Let $\struct {F, +, \times}$ be a field.
Suppose that:
$\map {\mathrm {Ann} } F = \set 0$
That is, the annihilator of $F$ consists of the zero only.
Then:
$\Char F = 0$
That is, the characteristic of $F$ is zero.
## Proof
Let the zero of $F$ be $0_F$ and the unity of $F$ be $1_F$.
By definition of characteristic, $\Char F = 0$ if and only if:
$\not \exists n \in \Z, n > 0: \forall r \in F: n \cdot r = 0_F$
That is, there exists no $n \in \Z, n > 0$ such that $n \cdot r = 0_F$ for all $r \in F$.
But note that $\forall r \in F: 0 \cdot r = 0_F$ by definition of integral multiple.
Aiming for a contradiction, suppose there exists a non-zero element of $\map {\mathrm {Ann} } F$.
From Non-Trivial Annihilator Contains Positive Integer, $\map {\mathrm {Ann} } F$ must contain a (strictly) positive integer.
But this would contradict the statement that $\Char F = 0$.
So it follows that:
$\map {\mathrm {Ann} } F = \set 0 \iff \Char F = 0$
$\Box$
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2023-04-02 06:32:23
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https://math.stackexchange.com/questions/1223409/how-to-find-the-derivative-of-an-integral-where-both-the-limit-and-the-integran/1223460
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# How to find the derivative of an integral where both, the limit and the integrand, are functions of x?
I found a good expository paper by Keith Conrad, which explains by examples the technique of derivative under the integral sign. Here's the link:
In these examples, the integrand is a function of both $x$ (the variable on which the differentiation is intended) and the parameter $t$. However, in most of the examples given in the paper, the limits of integration are constants.
Then, there're these following links from mathmistakes.info, which have examples where the limit of the integral is a function of $x$ but the integrand itself is independent of $x$ (i.e. the integrand is solely a function of $t$).
http://www.mathmistakes.info/facts/CalculusFacts/learn/doi/doi.html
http://www.mathmistakes.info/facts/CalculusFacts/learn/doi/doif.html
I was looking for techniques for differentiating integrals of the following kind $$\int_0^{g(x)} h(x,t) dt$$ where both the limit and the integrand are functions of $x$. I would prefer to have some examples of course, but any insight is appreciated.
• Define $F(x,y)=\int_0^y h(x,t)dt$, use the chain rule on $F(x,g(x))$. – Pedro Tamaroff Apr 7 '15 at 5:01
There is a full derivation here of a more general version:
$$f(x) = \int_{s(x)}^{g(x)} h(x, t) dt$$
$$\frac{df}{dx} = \int_{s(x)}^{g(x)} \partial_x h(x, t) dt + h(x, g(x)) \frac{dg}{dx} - h(x, s(x)) \frac{ds}{dx}$$
• When I think that I forgot the general rule by Leibnitz !! I am too old ! Thanks for the rule and the link. Cheers :-( – Claude Leibovici Apr 7 '15 at 9:56
For sure, this is not a complete answer (since I must confess I do not remember how it is established), but, as far as I know, I think that it is$$\frac{d}{dx}\int_0^{g(x)} h(x,t)\, dt= h\big(x,g(x)\big)\,\frac{dg(x)}{dx}+\int_0^{g(x)} \frac{dh(x,t)}{dx}\, dt$$ The first term is just the application of the fundamental theorem of calculus.
It is easy to control that, at least, this holds using $h(x,t)=a(x)+b(t)$, $h(x,t)=a(x)\,b(t)$, $h(x,t)=\frac{a(x)}{b(t)}$ and for almost any composition where we can separate the variables.
I played with some more complex functions in which the variables cannot be separated and it works.
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2021-08-05 07:02:57
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http://en.wikipedia.org/wiki/Latent_class_analysis
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# Latent class model
(Redirected from Latent class analysis)
In statistics, a latent class model (LCM) relates a set of observed (usually discrete) multivariate variables to a set of latent variables. It is a type of latent variable model. It is called a latent class model because the latent variable is discrete. A class is characterized by a pattern of conditional probabilities that indicate the chance that variables take on certain values.
Latent Class Analysis (LCA) is a subset of structural equation modeling, used to find groups or subtypes of cases in multivariate categorical data. These subtypes are called "latent classes".[1]
Confronted with a situation as follows, a researcher might choose to use LCA to understand the data: Imagine that symptoms a-d have been measured in a range of patients with diseases X Y and Z, and that disease X is associated with the presence of symptoms a, b, and c, disease Y with symptoms b, c, d, and disease Z with symptoms a, c and d.
The LCA will attempt to detect the presence of latent classes (the disease entities), creating patterns of association in the symptoms. As in factor analysis, the LCA can also be used to classify case according to their maximum likelihood class membership.[1]
Because the criterion for solving the LCA is to achieve latent classes within which there is no longer any association of one symptom with another (because the class is the disease which causes their association, and the set of diseases a patient has (or class a case is a member of) causes the symptom association, the symptoms will be "conditionally independent", i.e., conditional on class membership, they are no longer related.[1]
## Related methods
As in much of statistics, there are a large number of methods with distinct names and uses, which share a common relationship. Cluster analysis is, like LCA, used to discover taxon-like groups of cases in data. Multivariate mixture estimation (MME) is applicable to continuous data, and assumes that such data arise from a mixture of distributions: imagine a set of heights arising from a mixture of men and women. If a multivariate mixture estimation is constrained so that measures must be uncorrelated within each distribution it is termed latent profile analysis. Modified to handle discrete data, this constrained analysis is known as LCA. Discrete latent trait models further constrain the classes to formed from segments of a single dimension: essentially allocating members to classes on that dimension: an example would be assigning cases to social classes on a dimension of ability or merit.
As a practical instance, the variables could be multiple choice items of a political questionnaire. The data in this case consists of a N-way contingency table with answers to the items for a number of respondents. In this example, the latent variable refers to political opinion and the latent classes to political groups. Given group membership, the conditional probabilities specify the chance certain answers are chosen.
Within each latent class, the observed variables are statistically independent. This is an important aspect. Usually the observed variables are statistically dependent. By introducing the latent variable, independence is restored in the sense that within classes variables are independent (local independence). We then say that the association between the observed variables is explained by the classes of the latent variable (McCutcheon, 1987).
In one form the latent class model is written as
$p_{i_1, i_2, \ldots, i_N} \approx \sum_t^T p_t \, \prod_n^N p^n_{i_n, t},$
where T is the number of latent classes and pt are the so-called recruitment or unconditional probabilities that should sum to one. $p^n_{i_n, t}$ are the marginal or conditional probabilities.
For a two-way latent class model the form is
$p_{ij} \approx \sum_t^T p_t \, p_{it} \, p_{jt}.$
This two-way model is related to probabilistic latent semantic analysis and non-negative matrix factorization.
## Application
LCA may be used in many fields, such as: Collaborative Filtering [2] and Behavior Genetics [3]
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2014-07-30 06:49:45
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https://dedale.gitlab.io/page/tutorial/deployagents/
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# How to configure the agents
The 4 steps of the platform configuration can be modified independently. We present here the 2 steps related to the agents configuration : Defining the agents type & characteristics and implementing them. We assume that the two first steps related to the environment configuration are done. If not, configure your environment here. We will now see how to :
• Create java agents able to interact with the environment
# 1. Defining entities types and characteristics
Entities characteristics refers to the capabilities of your agents within the environment. They are defined in the entities files in the resources folder. This file is given to the system when you configure the environment. The structure of the file is the following :
mapname:mapName
with :
• agentType : wumpus, agentExplo, agentCollect, agentTanker,HumanControlled. The platform adapts the actions available to one agent within the environment according to its type. Wumpus are bots. Agents Explo and tanker are types of agents that cannot pick resources, only collector agents can. The size of one’s backPack is not taken into account. Only one agent of type HumanControlled is possible. This last agent is keyboard controlled (N(ext) and O(k)) and can only be used on your local computer.
• communicationRange : maximal radius authorised for this agent to communicate with others
• initialLocation : nodeId to deploy the agent or free is the system can choose randomly
• BackPackCapacityGold : maximum quantity of resources that the agent can transport. -1 if none.
• BackPackCapacityDiamond : maximum quantity of resources that the agent can transport. -1 if none.
• detectionRadius : distance from which the agent can be perceived
• lockpicking : level of lockpicking expertise of the agent [0,maxint]
• strength : level of strength the agent [0,maxint]
Illustrative example of an entities configuration file (available in the resources folder).
mapname:map2018MultiTypes
wumpus:Golem:0:free:200:0:1:0:0
agentExplo:Explo1:3:free:-1:-1:0:1:1
agentExplo:Explo2:3:free:-1:-1:0:2:1
agentCollect:Collect1:3:free:41:-1:0:1:2
agentTanker:Tanker1:3:free:300:200:0:1:5
## 2.1 Create an agent that can interact with the environment
• Your agent needs to extend the AbstractDedaleAgent class and add its initial behaviours to startBehaviours()
• Your agent must use the Dedale’s API to interact with the environment
### Simple agent structure
public class DummyMovingAgent extends AbstractDedaleAgent{
private static final long serialVersionUID = -2991562876411096907L;
/**
* This method is automatically called when "agent".start() is executed.
* Consider that Agent is launched for the first time.
* 1) set the agent attributes
*
*/
protected void setup(){
super.setup();
//get the parameters given when creating the agent into the object[]
final Object[] args = getArguments();
//use them as parameters for your behaviours
List<Behaviour> lb=new ArrayList<Behaviour>();
/************************************************
*
* ADD the behaviours of you agent here
*
************************************************/
/***
* MANDATORY TO ALLOW YOUR AGENT(S) TO BE DEPLOYED CORRECTLY WITH DEDALE
*/
}
/**
* This method is automatically called after doDelete()
*/
protected void takeDown(){
super.takeDown();
}
/**
* This method is automatically called before migration.
* You can add here all the saving you need
*/
protected void beforeMove(){
super.beforeMove();
}
/**
* This method is automatically called after migration to reload.
* You can add here all the info regarding the state you want your agent to restart from
*
*/
protected void afterMove(){
super.afterMove();
}
### Environment’s API
The complete API is available here
The key methods that you will use are :
• Observation, communication and movement :
• String getCurrentPosition() : Returns the current position of the agent
• List<Couple<String,List<Couple<Observation,Integer>>>> observe() : Returns the set of observables that can be perceived from the agent current position as a list of couple (position,list(ObservationType,Value)
• boolean moveTo(String myDestination) : Makes your agent move to myDestination (if reachable). This function must be the last one called within your behaviour
• void sendMessage(ACLMessage msg) : Send a message and manage the communication radius. You must use only this method when communicating.
• msg.setContent(String s) : To set a String as the message content
• msg.setContentObject(Serializable o) : To send a serializable object. Note that you mustn’t use both methods at the same time.
• Treasures and safes
• String getMyTreasureType(): Type of treasure that the agent can grab (only one type per agent)
• Set <Couple<Observation,Integer> getMyExpertise() : Expertise of the agent
• int getBackPackFreeSpace(): Space available in the agent backpack to store treasures
• boolean openLock(Observation o): Open the safe (type Gold or Diamond) if the required expertise is provided. This method aggregate all the expertises of the agents connex to the agent triggering this method.
• int pick(): Grab all of any of the treasure available on the current position (according to agent type, capacity and safe state)
• boolean EmptyMyBackPack(String agentSiloName) : Allow the agent to transfer its backpack within the Silo (Tanker) agent if it is in the vicinity
• Fights
• void throwGrenade(String locationId) : Attack all agents present on the given location (if any and if the location is reachable)
See the DummyMovingAgent and its RandomWalkBehaviour for an operational example of the API.
Here is a video tutorial illustrating the use of the API
Once your agent is written you just have to deploy it.
In the Principal.java file, you just have to add your agents in the createAgent() method, under the ADD YOUR AGENTS HERE comment :
//1) Get the container where the agent will appear
c = containerList.get(ConfigurationFile.LOCAL_CONTAINER2_NAME);
//2) Give the name of your agent, MUST be the same as the one given in the entities file.
agentName="Explo1";
//3) If you want to give specific parameters to your agent, add them here
Object [] entityParameters2={"My parameters"};
//4) Give the class name of your agent to let the system instantiate it
ag=createNewDedaleAgent(c, agentName, DummyMovingAgent.class.getName(), entityParameters2);
|
2021-09-18 19:36:17
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|
http://edoc.mpg.de/316890
|
Display Documents
history
ID: 316890.0, MPI für Gravitationsphysik / Laser Interferometry & Gravitational Wave Astronomy
Physical instrumental vetoes for gravitational-wave burst triggers
Authors:
Date of Publication (YYYY-MM-DD):2007
Title of Journal:Physical Review D
Volume:76
Sequence Number of Article:042004
Review Status:not specified
Audience:Not Specified
Abstract / Description:We present a robust strategy to \emph{veto} certain classes of instrumental glitches that appear at the output of interferometric gravitational-wave (GW) detectors.This veto method is physical' in the sense that, in order to veto a burst trigger, we make use of our knowledge of the coupling of different detector subsystems to the main detector output. The main idea behind this method is that the noise in an instrumental channel X can be \emph{transferred} to the detector output (channel H) using the \emph{transfer function} from X to H, provided the noise coupling is \emph{linear} and the transfer function is \emph{unique}. If a non-stationarity in channel H is causally related to one in channel X, the two have to be consistent with the transfer function. We formulate two methods for testing the consistency between the burst triggers in channel X and channel H. One method makes use of the \emph{null-stream} constructed from channel H and the \emph{transferred} channel X, and the second involves cross-correlating the two. We demonstrate the efficiency of the veto by injecting' instrumental glitches in the hardware of the GEO 600 detector. The \emph{veto safety} is demonstrated by performing GW-like hardware injections. We also show an example application of this method using 5 days of data from the fifth science run of GEO 600. The method is found to have very high veto efficiency with a very low accidental veto rate.
External Publication Status:published
Document Type:Article
Communicated by:Karsten Danzmann
Affiliations:
Identifiers:LOCALID:arXiv:0705.1111v1 [gr-qc]
|
2020-06-06 11:23:55
|
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|
https://www.sarthaks.com/2922517/the-number-of-times-a-particular-observation-occurs-in-a-given-data-is-called
|
The number of times a particular observation occurs in a given data is called
16 views
The number of times a particular observation occurs in a given data is called
A. Its Frequency
B. Its Range
C. Its mean
D. None of thes
by (71.2k points)
|
2022-09-26 19:47:26
|
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|
https://www.calculatorful.com/centimeters-to-inches
|
# Centimeters To Inches (Cm To In) | Convert CM To Inches
Mar 17, 2023 7:39 AM
Centimeters to inches conversion allows converting cm to in easily. How to convert cm to inches? How many centimeters is an inch? Just check it with Calculatorful's centimeters to inches converter.
## Inch - the commonly used unit of length in US and UK
The inch is a unit of length in the British imperial and the United States customary systems of measurement. The word inch is derived from the Roman uncia ("twelfth") and is occasionally used to translate analogous units in other measuring systems, which are commonly considered to be derived from the width of the human thumb.
In the past, standards for the precise length of an inch fluctuated, but with the adoption of the international yard in the 1950s and 1960s, the inch has been based on the metric system and defined as exactly 2.54 cm.
Inch is not commonly used internationally so you might find it difficult to convert inch to other units of length. Don't worry, our Calculatorful pool of converters is full of handy tools for you to choose from like Inches to Feet | Feet to Inches.
## Centimeter - the now-deprecated base unit of length
A centimeter (SI symbol cm) is a length unit in the International System of Units (SI) equal to one-hundredth of a meter, with centi being the SI prefix denoting a factor of $\frac{1}{100}$. In the now-deprecated centimeter-gram-second (CGS) unit system, the centimeter was the base unit of length.
Though scientists frequently prefer SI prefixes for factors of ${10}^{3}$, such as milli- and kilo, for many physical quantities, the centimeter remains a practical unit of length for many common measures. A centimeter is roughly the width of an average adult's fingernail.
## Relationship between inches to centimeters
Inches and centimeters are units of length in different systems. Therefore, to convert between them, we should understand their relationship clearly. The relationship between inch and cm is that one inch is exactly equal to 2.54 cm in the metric system.
1 in= 2.54 cm
In other words, the distance in centimeters is equal to the distance in inches times 2.54 cm.
Distance(cm)= Distance(inch) x 2.54
To convert the values from inches to centimeters, use inches to cm converter in order to find the values easily.
## Differences between inches and centimeters
As shown in the previous part, both inches and centimeters are units of length. However, they also have some distinct features, let's explore them in the table below:
Criteria Inches [in] Centimeters [cm] Definition The inch is a unit of length in the British imperial and the United States customary systems of measurement. A centimeter (SI symbol cm) is a length unit in the International System of Units (SI) equal to one-hundredth of a meter. Usage Inches is used to measure length, especially small distances. Centimeters is used to measure length, especially small distances. Abbreviation In Cm Value 1 in = 2.54 cm 1 cm = 0.393 in
## How many centimeters is an inch?
1 centimeter is equal to 0.3937 inches, hence 2.54 centimeters is an inch
## Converting inches to centimeters with formulas and examples
To convert centimeters to inches, for example, 30 cm to inches, you can do in 3 steps:
1. Take the value in cm, which is 30 in this case
2. Multiply it with 0.3937, since there are 2.54 centimeters in one inch, hence 0.3937 inches in 1 cm
3. That’s it! The result is 11.811 inches.
Now you know how to convert centimeters to inches, you might be interested in how other measurement units relate to others. Learn more in Calculatorful in Millimeters to inches | Miles to kilometers
### Example 1: What is 1 cm equal to in inches?
One centimeter is equal to 0.393701 inches.
### Example 2: How do you convert centimeters to inches?
To convert cm to inches, divide your cm figure by 2.54 or multiply it by 0.3937. As an example, let's say you have a piece of wood measuring 50cm and you want to convert it into inches. To get your answer, divide your cm figure by 2.54. So, 50 ÷ 2.54 = 19.685 inches.
## Centimeters to inches (cm to in) conversion table
Table for reference of conversion between common cm to in
Centimeters (cm) Inches (in) Centimeters (cm) to Inches (in) 1 centimeter 0,3937 inches 1 centimeter is equal to 0,3937 inches 2 centimeters 0,7874 inches 2 centimeters is equal to 0,7874 inches 3 centimeters 1,1811 inches 3 centimeters is equal to 1,1811 inches 4 centimeters 1,5748 inches 4 centimeters is equal to 1,5748 inches 5 centimeters 1,9685 inches 5 centimeters is equal to 1,9685 inches 6 centimeters 2,3622 inches 6 centimeters is equal to 2,3622 inches 7 centimeters 2,7559 inches 7 centimeters is equal to 2,7559 inches 8 centimeters 3,1496 inches 8 centimeters is equal to 3,1496 inches 9 centimeters 3,5433 inches 9 centimeters is equal to 3,5433 inches 10 centimeters 3,937 inches 10 centimeters is equal to 3,937 inches 11 centimeters 4,3307 inches 11 centimeters is equal to 4,3307 inches 12 centimeters 4,7244 inches 12 centimeters is equal to 4,7244 inches 13 centimeters 5,1181 inches 13 centimeters is equal to 5,1181 inches 14 centimeters 5,5118 inches 14 centimeters is equal to 5,5118 inches 15 centimeters 5,9055 inches 15 centimeters is equal to 5,9055 inches 16 centimeters 6,2992 inches 16 centimeters is equal to 6,2992 inches 17 centimeters 6,6929 inches 17 centimeters is equal to 6,6929 inches 18 centimeters 7,0866 inches 18 centimeters is equal to 7,0866 inches 19 centimeters 7,4803 inches 19 centimeters is equal to 7,4803 inches 20 centimeters 7,874 inches 20 centimeters is equal to 7,874 inches 21 centimeters 8,2677 inches 21 centimeters is equal to 8,2677 inches 22 centimeters 8,6614 inches 22 centimeters is equal to 8,6614 inches 23 centimeters 9,0551 inches 23 centimeters is equal to 9,0551 inches 24 centimeters 9,4488 inches 24 centimeters is equal to 9,4488 inches 25 centimeters 9,8425 inches 25 centimeters is equal to 9,8425 inches 26 centimeters 10,2362 inches 26 centimeters is equal to 10,2362 inches 27 centimeters 10,6299 inches 27 centimeters is equal to 10,6299 inches 28 centimeters 11,0236 inches 28 centimeters is equal to 11,0236 inches 29 centimeters 11,4173 inches 29 centimeters is equal to 11,4173 inches 30 centimeters 11,811 inches 30 centimeters is equal to 11,811 inches 31 centimeters 12,2047 inches 31 centimeters is equal to 12,2047 inches 32 centimeters 12,5984 inches 32 centimeters is equal to 12,5984 inches 33 centimeters 12,9921 inches 33 centimeters is equal to 12,9921 inches 34 centimeters 13,3858 inches 34 centimeters is equal to 13,3858 inches 35 centimeters 13,7795 inches 35 centimeters is equal to 13,7795 inches 36 centimeters 14,1732 inches 36 centimeters is equal to 14,1732 inches 37 centimeters 14,5669 inches 37 centimeters is equal to 14,5669 inches 38 centimeters 14,9606 inches 38 centimeters is equal to 14,9606 inches 39 centimeters 15,3543 inches 39 centimeters is equal to 15,3543 inches 40 centimeters 15,748 inches 40 centimeters is equal to 15,748 inches 41 centimeters 16,1417 inches 41 centimeters is equal to 16,1417 inches 42 centimeters 16,5354 inches 42 centimeters is equal to 16,5354 inches 43 centimeters 16,9291 inches 43 centimeters is equal to 16,9291 inches 44 centimeters 17,3228 inches 44 centimeters is equal to 17,3228 inches 45 centimeters 17,7165 inches 45 centimeters is equal to 17,7165 inches 46 centimeters 18,1102 inches 46 centimeters is equal to 18,1102 inches 47 centimeters 18,5039 inches 47 centimeters is equal to 18,5039 inches 48 centimeters 18,8976 inches 48 centimeters is equal to 18,8976 inches 49 centimeters 19,2913 inches 49 centimeters is equal to 19,2913 inches 50 centimeters 19,685 inches 50 centimeters is equal to 19,685 inches 51 centimeters 20,0787 inches 51 centimeters is equal to 20,0787 inches 52 centimeters 20,4724 inches 52 centimeters is equal to 20,4724 inches 53 centimeters 20,8661 inches 53 centimeters is equal to 20,8661 inches 54 centimeters 21,2598 inches 54 centimeters is equal to 21,2598 inches 55 centimeters 21,6535 inches 55 centimeters is equal to 21,6535 inches 56 centimeters 22,0472 inches 56 centimeters is equal to 22,0472 inches 57 centimeters 22,4409 inches 57 centimeters is equal to 22,4409 inches 58 centimeters 22,8346 inches 58 centimeters is equal to 22,8346 inches 59 centimeters 23,2283 inches 59 centimeters is equal to 23,2283 inches 60 centimeters 23,622 inches 60 centimeters is equal to 23,622 inches 61 centimeters 24,0157 inches 61 centimeters is equal to 24,0157 inches 62 centimeters 24,4094 inches 62 centimeters is equal to 24,4094 inches 63 centimeters 24,8031 inches 63 centimeters is equal to 24,8031 inches 64 centimeters 25,1968 inches 64 centimeters is equal to 25,1968 inches 65 centimeters 25,5905 inches 65 centimeters is equal to 25,5905 inches 66 centimeters 25,9842 inches 66 centimeters is equal to 25,9842 inches 67 centimeters 26,3779 inches 67 centimeters is equal to 26,3779 inches 68 centimeters 26,7716 inches 68 centimeters is equal to 26,7716 inches 69 centimeters 27,1653 inches 69 centimeters is equal to 27,1653 inches 70 centimeters 27,559 inches 70 centimeters is equal to 27,559 inches 71 centimeters 27,9527 inches 71 centimeters is equal to 27,9527 inches 72 centimeters 28,3464 inches 72 centimeters is equal to 28,3464 inches 73 centimeters 28,7401 inches 73 centimeters is equal to 28,7401 inches 74 centimeters 29,1338 inches 74 centimeters is equal to 29,1338 inches 75 centimeters 29,5275 inches 75 centimeters is equal to 29,5275 inches 76 centimeters 29,9212 inches 76 centimeters is equal to 29,9212 inches 77 centimeters 30,3149 inches 77 centimeters is equal to 30,3149 inches 78 centimeters 30,7086 inches 78 centimeters is equal to 30,7086 inches 79 centimeters 31,1023 inches 79 centimeters is equal to 31,1023 inches 80 centimeters 31,496 inches 80 centimeters is equal to 31,496 inches 81 centimeters 31,8897 inches 81 centimeters is equal to 31,8897 inches 82 centimeters 32,2834 inches 82 centimeters is equal to 32,2834 inches 83 centimeters 32,6771 inches 83 centimeters is equal to 32,6771 inches 84 centimeters 33,0708 inches 84 centimeters is equal to 33,0708 inches 85 centimeters 33,4645 inches 85 centimeters is equal to 33,4645 inches 86 centimeters 33,8582 inches 86 centimeters is equal to 33,8582 inches 87 centimeters 34,2519 inches 87 centimeters is equal to 34,2519 inches 88 centimeters 34,6456 inches 88 centimeters is equal to 34,6456 inches 89 centimeters 35,0393 inches 89 centimeters is equal to 35,0393 inches 90 centimeters 35,433 inches 90 centimeters is equal to 35,433 inches 91 centimeters 35,8267 inches 91 centimeters is equal to 35,8267 inches 92 centimeters 36,2204 inches 92 centimeters is equal to 36,2204 inches 93 centimeters 36,6141 inches 93 centimeters is equal to 36,6141 inches 94 centimeters 37,0078 inches 94 centimeters is equal to 37,0078 inches 95 centimeters 37,4015 inches 95 centimeters is equal to 37,4015 inches 96 centimeters 37,7952 inches 96 centimeters is equal to 37,7952 inches 97 centimeters 38,1889 inches 97 centimeters is equal to 38,1889 inches 98 centimeters 38,5826 inches 98 centimeters is equal to 38,5826 inches 99 centimeters 38,9763 inches 99 centimeters is equal to 38,9763 inches 100 centimeters 39,37 inches 100 centimeters is equal to 39,37 inches
## FAQs about centimeters to inches
### How do I convert 16 cm to inches?
To convert 16 cm to inches:
1. Take the number 16.
2. Multiply it with 0.3937.
3. The result is 6.2992 inches.
### How do I convert 45 cm to inches?
To convert 45 cm to inches:
1. Take the number 45.
2. Multiply it with 0.3937.
3. The result is 17.7165 inches.
## Conclusion
In this article, you have learned how to convert centimeters to inches. The conversion of cm to in is often needed in various fields such as engineering, architecture, construction, and other.
Calculator
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Provide centimeter (cm) number to convert to inch (in).
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2023-04-02 06:15:09
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http://nrich.maths.org/8328/index?nomenu=1
|
Annaliese threw her beanbag $20$ paces. Ophilia threw her beanbag $18$ paces, later Janine came along and threw her beanbag $21$ paces.
Who was the winner?
Kai hopped on one leg for $25$ hops. Anna hopped on one leg for $32$ hops. Teck hopped on one leg for $29$ hops.
Who was the winner?
Amit ran across the playground in $20$ seconds. Sara took $18$ seconds. Marek took $17$ seconds.
Who was the winner?
Why don't you try these activities for yourself?
How far can you throw a beanbag? How many hops can you do? How long does it take you to run across your playground?
Photograph acknowledgements
http://www.sensoryprocessing.com
http://photographicdictionary.com/h/hop
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2016-02-13 21:41:46
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https://www2.math.binghamton.edu/p/people/grads/kelley/research
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### Sidebar
people:grads:kelley:research
You can find my research interests here. This page (you see now) exists only because I made a mistake in $\LaTeX$ in one or more of my documents; I did not use the url package. The url for my research page actually is typed correctly there though, but the link is wrong if you clicked it.
people/grads/kelley/research.txt · Last modified: 2016/12/14 12:05 by kelley
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2019-07-21 02:19:43
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http://cpr-hepex.blogspot.com/2013/06/13060885-v-topor-pop-et-al.html
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## Open Charm Production in $p + p$ and Pb + Pb collisions at the CERN Large Hadron Collider [PDF]
V. Topor Pop, M. Gyulassy, J. Barrette, C. Gale, M. Petrovici
Effects of strong longitudinal colour electric fields (SCF), shadowing and quenching on the open prompt charm mesons (D$^0$, D$^+$, D$^{*+}$, D${_s}{^+}$) production in central Pb + Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV are investigated within the framework of the {\small HIJING/B\=B v2.0} model. We compute nuclear modification factor $R_{\rm PbPb}^{\rm D}$, and show that the above nuclear effects constitute important dynamical mechanisms in the description of experimental data. The strength of colour fields (the string tension $\kappa$), partonic energy loss and jet quenching process as embedded in the model lead to a suppression factor consistent with recent published data. Ratios of strange to non-strange prompt charm mesons in central Pb + Pb and minimum bias (MB) $p + p$ collisions at 2.76 TeV, are also discussed. Finally MB $p + p$ collisions which constitute theoretical baseline in our calculations is studied at the centre of mass energy $\sqrt{s}$ = 2.76 TeV and 7 TeV.
View original: http://arxiv.org/abs/1306.0885
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2017-08-17 03:59:52
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https://ftp.aimsciences.org/article/doi/10.3934/fods.2021002?viewType=html
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# American Institute of Mathematical Sciences
March 2021, 3(1): 1-26. doi: 10.3934/fods.2021002
## The rankability of weighted data from pairwise comparisons
1 Department of Computer Science and Software Engineering, California Polytechnic State University, San Luis Obispo, CA, USA 2 Department of Mathematics and Computer Science, Davidson College, Davidson, NC, USA 3 Mathematics Department, College of Charleston, Charleston, SC, USA
* Corresponding author: Langville
Received August 2020 Revised December 2020 Published March 2021 Early access January 2021
In prior work [4], Anderson et al. introduced a new problem, the rankability problem, which refers to a dataset's inherent ability to produce a meaningful ranking of its items. Ranking is a fundamental data science task with numerous applications that include web search, data mining, cybersecurity, machine learning, and statistical learning theory. Yet little attention has been paid to the question of whether a dataset is suitable for ranking. As a result, when a ranking method is applied to a dataset with low rankability, the resulting ranking may not be reliable.
Rankability paper [4] and its methods studied unweighted data for which the dominance relations are binary, i.e., an item either dominates or is dominated by another item. In this paper, we extend rankability methods to weighted data for which an item may dominate another by any finite amount. We present combinatorial approaches to a weighted rankability measure and apply our new measure to several weighted datasets.
Citation: Paul E. Anderson, Timothy P. Chartier, Amy N. Langville, Kathryn E. Pedings-Behling. The rankability of weighted data from pairwise comparisons. Foundations of Data Science, 2021, 3 (1) : 1-26. doi: 10.3934/fods.2021002
##### References:
[1] T. Achterberg, Scip: Solving constraint integer programs, Mathematical Programming Computation, 1 (2009), 1-41. doi: 10.1007/s12532-008-0001-1. [2] N. Ailon, M. Charikar and A. Newman, Aggregating inconsistent information: Ranking and clustering, Journal of the ACM, 55 (2008), 27 pp. doi: 10.1145/1411509.1411513. [3] I. Ali, W. D. Cook and M. Kress, On the minimum violations ranking of a tournament, Management Science, 32 (1986), 660-672. doi: 10.1287/mnsc.32.6.660. [4] P. Anderson, T. Chartier and A. Langville, The rankability of data, SIAM Journal on the Mathematics of Data Science, (2019), 121–143. doi: 10.1137/18M1183595. [5] P. Anderson, T. Chartier, A. Langville and K. Pedings-Behling, IGARDS technical report, 2019. Available from: https://igards.github.io/research/IGARDS_Technical_Report_November_2019.pdf. [6] P. Anderson, T. Chartier, A. Langville and K. Pedings-Behling, Revisiting rankability of unweighted data technical report, 2020. Available from: https://igards.github.io/research/Revisiting_Rankability_Unweighted_Data.pdf. [7] R. D. Armstrong, W. D. Cook and L. M. Seiford, Priority ranking and consensus formation: The case of ties, Management Science, 28 (1982), 638-645. doi: 10.1287/mnsc.28.6.638. [8] J. Brenner and P. Keating, Chaos kills, ESPN, The Magazine, (2016), 20–23. [9] S. Brin and L. Page, The anatomy of a large-scale hypertextual web search engine, Computer Networks and ISDN Systems, 33 (1998), 107–117. doi: 10.1016/S0169-7552(98)00110-X. [10] S. Brin, L. Page, R. Motwami and T. Winograd, The PageRank citation ranking: Bringing order to the web, Tech. Report 1999-0120, Computer Science Department, Stanford University, 1999. [11] T. R. Cameron, A. N. Langville and H. C. Smith, On the graph Laplacian and the rankability of data, Linear Algebra and its Applications, 588 (2020), 81-100. doi: 10.1016/j.laa.2019.11.026. [12] C. R. Cassady, L. M. Maillart and S. Salman, Ranking sports teams: A customizable quadratic assignment approach, INFORMS: Interfaces, 35 (2005), 497-510. doi: 10.1287/inte.1050.0171. [13] T. P. Chartier, E. Kreutzer, A. N. Langville and K. E. Pedings, Sensitivity of ranking vectors, SIAM Journal on Scientific Computing, 33 (2011), 1077–1102. doi: 10.1137/090772745. [14] B. J. Coleman, Minimizing game score violations in college football rankings, INFORMS: Interfaces, 35 (2005), 483-496. doi: 10.1287/inte.1050.0172. [15] W. D. Cook and L. M. Seiford, Priority ranking and consensus formation, Management Science, 24 (1978), 1721-1732. doi: 10.1287/mnsc.24.16.1721. [16] T. G. Dietterich, Approximate statistical tests for comparing supervised classification learning algorithms, Neural Computation, 10 (1998), 1895-1923. doi: 10.1162/089976698300017197. [17] S. Dutta, S. H. Jacobson and J. J. Sauppe, Identifying ncaa tournament upsets using balance optimization subset selection, Journal of Quantitative Analysis in Sports, 13 (2017), 79-93. [18] M. R. Garey and D. S. Johnson, Computers and Intractability: A Guide to the Theory of NP-Completeness, Freeman, 1979. [19] F. M. Harper and J. A. Konstan, The movielens datasets: History and context, Acm Transactions on Interactive Intelligent Systems (TIIS), 5 (2015), 1-19. doi: 10.1145/2827872. [20] X. Jiang, L.-H. Lim, Y. Yao and Y. Ye, Statistical ranking and combinatorial Hodge theory, Mathematical Programming, 127 (2011), 203-244. doi: 10.1007/s10107-010-0419-x. [21] P. Keating, personal communication. [22] Y. Kondo, Triangulation of input-output tables based on mixed integer programs for inter-temporal and inter-regional comparison of production structures, Journal of Economic Structures, 3 (2014), 1-19. doi: 10.1186/2193-2409-3-2. [23] A. N. Langville and C. D. Meyer, Who's #1? The Science of Rating and Ranking Items, Princeton University Press, Princeton, 2012. [24] A. N. Langville, K. Pedings and Y. Yamamoto, A minimum violations ranking method, Optimization and Engineering, (2011), 1–22. doi: 10.1007/s11081-011-9135-5. [25] A. S. Lee and D. R. Shier, A method for ranking teams based on simple paths, UMAP Journal, 39 (2018), 353-371. [26] W. W. Leontief, Input-Output Economics, 2nd edition, Oxford University Press, 1986. doi: 10.1038/scientificamerican1051-15. [27] M. J. Lopez and G. J. Matthews, Building an NCAA men's basketball predictive model and quantifying its success, Journal of Quantitative Analysis in Sports, 11 (2015), 5-12. doi: 10.1515/jqas-2014-0058. [28] R. Marti and G. Reinelt, The linear ordering problem: Exact and heuristic methods in combinatorial optimization, AMS, 2011. doi: 10.1007/978-3-642-16729-4. [29] S. Mehrotra and Y. Ye, Finding an interior point in the optimal face of linear programs, 62 (1993), 497–515. doi: 10.1007/BF01585180. [30] J. Park, On minimum violations ranking in paired comparisons, 2005. [31] G. Reinelt, The Linear Ordering Problem: Algorithms and Applications, Heldermann Verlag, 1985. [32] V. N. Vapnik, The Nature of Statistical Learning Theory, Springer-Verlag, Berlin, Heidelberg, 1995. doi: 10.1007/978-1-4757-2440-0. [33] S. Wartenberg, How many people will fill out March Madness brackets?, The Columbus Dispatch, (2015).
show all references
##### References:
[1] T. Achterberg, Scip: Solving constraint integer programs, Mathematical Programming Computation, 1 (2009), 1-41. doi: 10.1007/s12532-008-0001-1. [2] N. Ailon, M. Charikar and A. Newman, Aggregating inconsistent information: Ranking and clustering, Journal of the ACM, 55 (2008), 27 pp. doi: 10.1145/1411509.1411513. [3] I. Ali, W. D. Cook and M. Kress, On the minimum violations ranking of a tournament, Management Science, 32 (1986), 660-672. doi: 10.1287/mnsc.32.6.660. [4] P. Anderson, T. Chartier and A. Langville, The rankability of data, SIAM Journal on the Mathematics of Data Science, (2019), 121–143. doi: 10.1137/18M1183595. [5] P. Anderson, T. Chartier, A. Langville and K. Pedings-Behling, IGARDS technical report, 2019. Available from: https://igards.github.io/research/IGARDS_Technical_Report_November_2019.pdf. [6] P. Anderson, T. Chartier, A. Langville and K. Pedings-Behling, Revisiting rankability of unweighted data technical report, 2020. Available from: https://igards.github.io/research/Revisiting_Rankability_Unweighted_Data.pdf. [7] R. D. Armstrong, W. D. Cook and L. M. Seiford, Priority ranking and consensus formation: The case of ties, Management Science, 28 (1982), 638-645. doi: 10.1287/mnsc.28.6.638. [8] J. Brenner and P. Keating, Chaos kills, ESPN, The Magazine, (2016), 20–23. [9] S. Brin and L. Page, The anatomy of a large-scale hypertextual web search engine, Computer Networks and ISDN Systems, 33 (1998), 107–117. doi: 10.1016/S0169-7552(98)00110-X. [10] S. Brin, L. Page, R. Motwami and T. Winograd, The PageRank citation ranking: Bringing order to the web, Tech. Report 1999-0120, Computer Science Department, Stanford University, 1999. [11] T. R. Cameron, A. N. Langville and H. C. Smith, On the graph Laplacian and the rankability of data, Linear Algebra and its Applications, 588 (2020), 81-100. doi: 10.1016/j.laa.2019.11.026. [12] C. R. Cassady, L. M. Maillart and S. Salman, Ranking sports teams: A customizable quadratic assignment approach, INFORMS: Interfaces, 35 (2005), 497-510. doi: 10.1287/inte.1050.0171. [13] T. P. Chartier, E. Kreutzer, A. N. Langville and K. E. Pedings, Sensitivity of ranking vectors, SIAM Journal on Scientific Computing, 33 (2011), 1077–1102. doi: 10.1137/090772745. [14] B. J. Coleman, Minimizing game score violations in college football rankings, INFORMS: Interfaces, 35 (2005), 483-496. doi: 10.1287/inte.1050.0172. [15] W. D. Cook and L. M. Seiford, Priority ranking and consensus formation, Management Science, 24 (1978), 1721-1732. doi: 10.1287/mnsc.24.16.1721. [16] T. G. Dietterich, Approximate statistical tests for comparing supervised classification learning algorithms, Neural Computation, 10 (1998), 1895-1923. doi: 10.1162/089976698300017197. [17] S. Dutta, S. H. Jacobson and J. J. Sauppe, Identifying ncaa tournament upsets using balance optimization subset selection, Journal of Quantitative Analysis in Sports, 13 (2017), 79-93. [18] M. R. Garey and D. S. Johnson, Computers and Intractability: A Guide to the Theory of NP-Completeness, Freeman, 1979. [19] F. M. Harper and J. A. Konstan, The movielens datasets: History and context, Acm Transactions on Interactive Intelligent Systems (TIIS), 5 (2015), 1-19. doi: 10.1145/2827872. [20] X. Jiang, L.-H. Lim, Y. Yao and Y. Ye, Statistical ranking and combinatorial Hodge theory, Mathematical Programming, 127 (2011), 203-244. doi: 10.1007/s10107-010-0419-x. [21] P. Keating, personal communication. [22] Y. Kondo, Triangulation of input-output tables based on mixed integer programs for inter-temporal and inter-regional comparison of production structures, Journal of Economic Structures, 3 (2014), 1-19. doi: 10.1186/2193-2409-3-2. [23] A. N. Langville and C. D. Meyer, Who's #1? The Science of Rating and Ranking Items, Princeton University Press, Princeton, 2012. [24] A. N. Langville, K. Pedings and Y. Yamamoto, A minimum violations ranking method, Optimization and Engineering, (2011), 1–22. doi: 10.1007/s11081-011-9135-5. [25] A. S. Lee and D. R. Shier, A method for ranking teams based on simple paths, UMAP Journal, 39 (2018), 353-371. [26] W. W. Leontief, Input-Output Economics, 2nd edition, Oxford University Press, 1986. doi: 10.1038/scientificamerican1051-15. [27] M. J. Lopez and G. J. Matthews, Building an NCAA men's basketball predictive model and quantifying its success, Journal of Quantitative Analysis in Sports, 11 (2015), 5-12. doi: 10.1515/jqas-2014-0058. [28] R. Marti and G. Reinelt, The linear ordering problem: Exact and heuristic methods in combinatorial optimization, AMS, 2011. doi: 10.1007/978-3-642-16729-4. [29] S. Mehrotra and Y. Ye, Finding an interior point in the optimal face of linear programs, 62 (1993), 497–515. doi: 10.1007/BF01585180. [30] J. Park, On minimum violations ranking in paired comparisons, 2005. [31] G. Reinelt, The Linear Ordering Problem: Algorithms and Applications, Heldermann Verlag, 1985. [32] V. N. Vapnik, The Nature of Statistical Learning Theory, Springer-Verlag, Berlin, Heidelberg, 1995. doi: 10.1007/978-1-4757-2440-0. [33] S. Wartenberg, How many people will fill out March Madness brackets?, The Columbus Dispatch, (2015).
Cityplot of $8 \times 8$ data matrix with original ordering and hillside reordering
Cityplots of $n = 8$ college football data matrices with the original ordering (left) and the optimal hillside reordering (right). The top row is the 2008 season, a less rankable season with hillside $\delta = 155$ and $\rho = 6$. The bottom row is the 2005 season, a more rankable season with hillside $\delta = 92$ and $\rho = 4$
Approximate fractional matrix ${\bf X}^*({\bf r}, {\bf r})$ for Example 1 obtained by the Interior Point solver of the linear programming relaxation
Spaghetti plots and summary of diversity of $P$ sets for Examples 1 and 2
Two maximally discordant optimal solutions for Examples 1 and 2
$X^*$ color-coded visualization of years 2009, 2013, and 2016 NCAA March Madness using the top performing LOP formulation
$X^*$ color-coded visualization of years 2009, 2013, and 2016 NCAA March Madness using the top performing hillside formulation
$X^*$ color-coded visualization for each year of NCAA March Madness using the top performing LOP formulation
$X^*$ color-coded visualization for each year of NCAA March Madness using the top performing hillside formulation
Sample Input/Output economic data based on Japan 2005 [22] (A) and its graphical representation in (B)
Sample of movie rating data based on MovieLens [19] (A) and graphical representation of user rating data transformed into pairwise comparisons (B)
Sample of NCAA Men's Basketball games is shown in (A) and the graphical representation of the aggregate dominance information, i.e., ${\bf D}$ is shown in (B)
5 fold cross-validation results for predicting the upset measure for NCAA Men's March Madness 2002-2018
Dominance Method Parameters Method MAE 1 Direct+Indirect dt=0, st=1, wi=1 Hillside 3.148221 2 Direct+Indirect dt=0, st=0, wi=1 Hillside 3.148221 3 Direct+Indirect dt=1, st=0, wi=1 LOP 3.172793 4 Direct+Indirect dt=1, st=1, wi=1 LOP 3.172793 5 Direct+Indirect dt=0, st=0, wi=0.25 Hillside 3.213978 6 Direct+Indirect dt=0, st=1, wi=0.25 Hillside 3.213978 7 Direct dt=2 Hillside 3.309455 8 Direct+Indirect dt=2, st=1, wi=1 LOP 3.311588 9 Direct+Indirect dt=2, st=0, wi=1 LOP 3.311588 10 Direct+Indirect dt=2, st=2, wi=0.5 Hillside 3.331698
Dominance Method Parameters Method MAE 1 Direct+Indirect dt=0, st=1, wi=1 Hillside 3.148221 2 Direct+Indirect dt=0, st=0, wi=1 Hillside 3.148221 3 Direct+Indirect dt=1, st=0, wi=1 LOP 3.172793 4 Direct+Indirect dt=1, st=1, wi=1 LOP 3.172793 5 Direct+Indirect dt=0, st=0, wi=0.25 Hillside 3.213978 6 Direct+Indirect dt=0, st=1, wi=0.25 Hillside 3.213978 7 Direct dt=2 Hillside 3.309455 8 Direct+Indirect dt=2, st=1, wi=1 LOP 3.311588 9 Direct+Indirect dt=2, st=0, wi=1 LOP 3.311588 10 Direct+Indirect dt=2, st=2, wi=0.5 Hillside 3.331698
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## Tools
Article outline
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2022-05-24 12:32:11
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https://gamedev.stackexchange.com/questions/96247/raycast-method-always-outputting-false
|
# RayCast method always outputting False
I am having trouble executing a raycast to check if there is anything between the player sprite and a second sprite. This is my code :
void Start () {
play1 = GameObject.Find("player");
game1 = GameObject.Find("lightidle_0");
}
// Update is called once per frame
void Update () {
Vector3 playpos = play1.transform.position;
Vector3 gamepos = game1.transform.position;
Vector3 defvector = new Vector3 (1, 0, 0);
Ray playray= new Ray (playpos, defvector);
float distance = playpos.x - gamepos.x;
if (distance > 0) {
Debug.Log (Physics.Raycast(playray,distance));
}
else { defvector = -defvector;
Debug.Log (Physics.Raycast(playray,distance));
}
So supposedly, if there is anything between both objects, Raycast should return true. But it is always stuck on false, I have debugged, and tried everything, its value never changes, no matter where both objects are located, I added 2 huge colliders on both sides of the scene and it still outputs false.
I also added a Debug.DrawRay (playpos, defvector * distance); but the ray isn't drawn at all, so it means that is the reason of the error, but why? I can't figure it out.
I don't quite know what was the problem here, but as a fix i changed the Physics.Raycast command to
Physics2D.Linecast(startposition, endposition);
This fixed the problem. I also made 2 new objects childs of the player, and the npc, and fixed it all up.
Reference to how I did it all in this video : https://www.youtube.com/watch?v=cJj7-Sy03HQ
tried:
Physics.Raycast(playpos ,playpos - gamepos, (playpos - gamepos).magnitude)
or
Physics.Raycast(playpos ,gamepos-playpos , (gamepos -playpos ).magnitude)
?
plus keep in mind: "Raycasts will not detect colliders for which the raycast origin is inside the collider"
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2020-12-05 05:42:12
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http://tex.stackexchange.com/questions/321/align-vs-equation/331
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# align vs equation
I always use align in my documents, and avoid equation. Is there anything wrong with that? My reasoning behind this: align > equation, so why not use it?
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– Harish Kumar Dec 14 '12 at 13:03
While not exactly a bad idea in principle, unfortunately it is a bad idea in practise because align doesn't have the same feature as equation whereby less vertical space is added if a small equation is displayed after a paragraph that ended early on the line. For example, consider
\documentclass[twocolumn]{article}
\usepackage{amsmath}
\begin{document}
hello
$a+b=c$
hello
\begin{align}
a+b&=c
\end{align}
\end{document}
You should easily be able to see the extra space after the second ‘hello’.
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What are you supposed to do though if you need to use an align environment (i.e., if typeseting an equation environment with an aligned inside is not sufficient)? – mSSM May 21 '12 at 13:11 If you need to use align then you just use align :) Just be aware of the difference, that's all. – Will Robertson May 22 '12 at 2:01
Will all due respect to Will Robertson, actually I think that it is a bad idea in principle, because they mean different things and markup (be it *TeX, HTML,...) should be logical as much as possible.
If you are typesetting an equation, then use equation and if you desire alignment you can use aligned blocks inside the equation.
You can decide easily whether you are typesetting an equation or not, by thinking how to want to reference it. If you only want one equation number to be displayed and see yourself suppressing by hand any additional equation numbers, (say by using \notag) then you are typesetting an equation and your markup should reflect that.
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I see what you mean about markup being logical and do agree with you in principle, but I think in this case the typesetting of the output is far more important than whether or not we can consider a single equation to be aligned with itself (and therefore 'logical' within an align environment). The difference in behaviour outlined by Will seems to me to provide a much better answer as to the actual difference between the two environments and where you could possibly run into trouble by choosing one over the other. – Michael Underwood Jul 27 '10 at 16:39
I interpret "not exactly a bad idea" as a polite way of saying not really a good idea. – Charles Stewart Jul 28 '10 at 9:24
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2013-05-22 04:00:28
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https://docs.chemaxon.com/display/docs/Protein+Data+Bank+%28PDB%29+file+format
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##### Page tree
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# Protein Data Bank (PDB) file format
## Import from PDB format
PDB files complying the PDB Contents Guide version 2.3 are processed, though with some negligible limitations. PDB files produced by various 3rd party applications may not comply the PDB standard. Most of these files are also properly handled though there might be exceptions.
All covalent bonds in proteins and in nucleic acids are properly assigned, but hydrogen bonds, sulphur and water bridges, coordinated bonds are not recognised yet. Covalent bonds in hetero groups are perceived based on geometry, bond types are guessed with some errors. Hydregon atoms are identified and bonded to the appropriate heavy atom eiter in chains, in hetero groups as well as in water molecules.
Multiple models are properly processed as well as insertions and modified residues.
### Import Options
H or +H Add explicit hydrogen atoms. PDB:H -H Remove explicit hydrogen atoms. PDB:-H c Omit CONECT records for hetero compounds. Bonds are detected by the PDB reader modul based on local geometry unless the b option is specified. PBD:c b Do not recognize bond order. All bonds either defined by CONECT records or generated by PDB import are represented as ANY bonds. Usage: PBD:b f# set bond length cut-off (default #: 1.12)
Codename: pdb
### Limitations
Standard record types listed below are not recognised by the current version of PDB import:
• Optional: OBSLTE, CAVEAT, SPRSDE, JRNL, REMARK, SEQADV, FTNOTE, HETSYN, FORMUL, SSBOND, LINK, HYDBND, SLTBRG, CISPEP, SITE, MTRIX1, MTRIX2, MTRIX3, TVECT, SIGATM, ANISOU, SIGUIJ
• Mandatory: CRYST1, ORIGX1, ORIGX2, ORIGX3, SCALE1, SCALE2, SCALE3, MASTER
The recognition and proper processing of these record types will be implemented in forthcoming releases on demand.
## Export to PDB format
Marvin exports simplified PDB files containing record types listed below:
• Title section:
• HEADER contains the following fields: classification="PROTEIN" (or imported value), date, idCode="NONE" (or imported value).
• TITLE, SOURCE, KEYWDS, EXPDTA: The imported value is exported. Default: "NULL".
• COMPND: The imported value is exported. Default: "MOLECULE: name", where "name" is the molecule name.
• AUTHOR: The imported value is exported. Default: "Marvin".
• REVDAT: The following line plus the imported value.
REVDAT N DD-MMM-YY 3
(N is the modification number, DD-MMM-YY is the date of the modification.)
• Coordinate section:
• ATOM and HETATM: The atom name includes the remoteness indicator and the branch designator character in case of amino acids. For non-standard residues, the atom name and the element symbol field contain the same value. The occupancy and the temperature factor are zero. The residue field contains one of the standard residue symbols.
• Connectivity section:
• CONECT: Only the first five fields are used. If the number of bonds is greater than four, a second CONECT line with the same atom serial number (first field) will be used.
• TER: Indicates the end of a chain. Imported but not exported in the current version.
• Book keeping section:
• MASTER
Export options can be specified in the format string. The format descriptor and the options are separated by a colon. Options listed below are available for PDB output.
H or +H Add explicit hydrogen atoms. PDB:H -H Remove explicit Hydrogen atoms. PDB:-H -c Do not store connections PDB:-c
### Limitations
The exporter writes the atoms in the molecule object's internal atom order which may be different from the order of residues in a chain. Thus export is still not reliable for macromolecules with residues.
• No labels
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2018-04-27 08:32:56
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