// SPDX-License-Identifier: BSD-3-Clause
// Copyright (c) 2024-2025, The OpenROAD Authors

# Author: Dimitris K. Fotakis
# Version: v1.0
# Date: 11/05/2024

Documentation of output file: diff_spef.out

This file is to provide documentation on the format of diff_spef.out file which is generated when running command: 
	diff_spef

Note: C++ function is in file extSpefIn.cpp: extSpef::printDiff
this is meant to provide imprtant stats, one line per net per type of R and C total values.
by running (grep netRes diff_spef.out | sort) it is easy to gauge range of %error (positive to negative) andby doing <awk> specific columns you can focus on insigts on error (big nets, nets with many vias, etc)

here is the description of the coluns:

column 1: % diff of db value wrt to ref value (which is parsed from the file in the diff_spef command)
column 2: db_value
column 3: D
column 4: [OK,HI,LO] depending on db_value being withing the range of bounds [lo,hi], greater than hi bound, lower than lo bound; bound values are in columns right after keyword: bounds:
column 5: % difference of db_value wrt hi value of bounds
column 6: ref
column 7: ref_value which is the value parsed from the file in command diff_spef
column 8: R
column 9: [OK,HI,LO] depending on ref_value being withing the range of bounds [lo,hi], greater than hi bound, lower than lo bound; bound values are in columns right after keyword: bounds:
column 10: % difference of ref_value wrt hi value of bounds
column 11: bounds:
column 12: lo_bound
column 13: hi_bound

if column 22 == netRes
        column 14: VR
        column 15: total_via_res
        column 16: V
        column 17: total_via_cnt
        column 18: L
        column 19: net_wire_length
        column 20: WC
        column 21: Wire (segment) Count (per DEF)
        column 22: [netRes] for (total net resistance)
        column 23: corner
        column 24: corner_index
        column 25: comma list with total_wire_length on every metal
        column 26: net_id
        column 27: net_name
else
        column 14: L
        column 15: net_wire_length
        column 16: WC
        column 17: Wire (segment) Count (per DEF)
        column 18: V
        column 19: total_via_cnt
        column 22: [netCap,gndNetCap,netCcap] for (total net capacitance, total ground capacitance, total coupling capacitance)
        column 23: corner
        column 24: corner_index
        column 25: comma list with total_wire_length on every metal
        column 26: net_id
        column 27: net_name