text
stringlengths 0
828
|
|---|
1.59056225126211695515E1,
|
-1.18331621121330003142E0,
|
]
|
# Approximation for interval z = sqrt(-2 log y ) between 2 and 8
|
# i.e., y between exp(-2) = .135 and exp(-32) = 1.27e-14.
|
P1 = [
|
4.05544892305962419923E0,
|
3.15251094599893866154E1,
|
5.71628192246421288162E1,
|
4.40805073893200834700E1,
|
1.46849561928858024014E1,
|
2.18663306850790267539E0,
|
-1.40256079171354495875E-1,
|
-3.50424626827848203418E-2,
|
-8.57456785154685413611E-4,
|
]
|
Q1 = [
|
1.57799883256466749731E1,
|
4.53907635128879210584E1,
|
4.13172038254672030440E1,
|
1.50425385692907503408E1,
|
2.50464946208309415979E0,
|
-1.42182922854787788574E-1,
|
-3.80806407691578277194E-2,
|
-9.33259480895457427372E-4,
|
]
|
# Approximation for interval z = sqrt(-2 log y ) between 8 and 64
|
# i.e., y between exp(-32) = 1.27e-14 and exp(-2048) = 3.67e-890.
|
P2 = [
|
3.23774891776946035970E0,
|
6.91522889068984211695E0,
|
3.93881025292474443415E0,
|
1.33303460815807542389E0,
|
2.01485389549179081538E-1,
|
1.23716634817820021358E-2,
|
3.01581553508235416007E-4,
|
2.65806974686737550832E-6,
|
6.23974539184983293730E-9,
|
]
|
Q2 = [
|
6.02427039364742014255E0,
|
3.67983563856160859403E0,
|
1.37702099489081330271E0,
|
2.16236993594496635890E-1,
|
1.34204006088543189037E-2,
|
3.28014464682127739104E-4,
|
2.89247864745380683936E-6,
|
6.79019408009981274425E-9,
|
]
|
sign_flag = 1
|
if y > (1 - EXP_NEG2):
|
y = 1 - y
|
sign_flag = 0
|
# Shortcut case where we don't need high precision
|
# between -0.135 and 0.135
|
if y > EXP_NEG2:
|
y -= 0.5
|
y2 = y ** 2
|
x = y + y * (y2 * _polevl(y2, P0, 4) / _p1evl(y2, Q0, 8))
|
x = x * ROOT_2PI
|
return x
|
x = math.sqrt(-2.0 * math.log(y))
|
x0 = x - math.log(x) / x
|
z = 1.0 / x
|
if x < 8.0: # y > exp(-32) = 1.2664165549e-14
|
x1 = z * _polevl(z, P1, 8) / _p1evl(z, Q1, 8)
|
else:
|
x1 = z * _polevl(z, P2, 8) / _p1evl(z, Q2, 8)
|
x = x0 - x1
|
if sign_flag != 0:
|
x = -x
|
return x"
|
1033,"def erfinv(z):
|
""""""
|
Calculate the inverse error function at point ``z``.
|
This is a direct port of the SciPy ``erfinv`` function, originally
|
written in C.
|
Parameters
|
----------
|
z : numeric
|
Returns
|
-------
|
float
|
References
|
----------
|
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