Created a new script that deals with the problem of parameter
names in the monte carlo parameter files that shadow names of
devices. ngspice does not handle this; this could be an ngspice
error, but the best practice is not to have confusing parameter
names, so the script modifies the names by stripping off the
leading sky130_fd_pr__ from the parameter name so that it no
longer conflicts with the device name.
diff --git a/sky130/custom/scripts/montecarlo_hack.py b/sky130/custom/scripts/montecarlo_hack.py
new file mode 100755
index 0000000..2c8ce48
--- /dev/null
+++ b/sky130/custom/scripts/montecarlo_hack.py
@@ -0,0 +1,83 @@
+#!/usr/bin/env python3
+#
+#--------------------------------------------------------------------
+# Workaround for the problem that ngspice is unable to accept a
+# parameter name that shadows a device name. Parameters in the
+# files critical.spice and montecarlo.spice that shadow parameter
+# names have the leading sky130_fd_pr__ stripped off to prevent
+# this from being a problem.
+#--------------------------------------------------------------------
+
+import os
+import re
+import sys
+
+searchpath = ['sky130A/libs.tech/ngspice/parameters/critical.spice',
+ 'sky130A/libs.tech/ngspice/parameters/montecarlo.spice']
+
+if len(sys.argv) > 1:
+ searchpath = sys.argv[1]
+
+# Flag all parameters that have the same name as devices.
+# These parameters are unused and must be deleted.
+
+excludelist = [
+ 'sky130_fd_pr__nfet_20v0_nvt_iso',
+ 'sky130_fd_pr__nfet_20v0_nvt',
+ 'sky130_fd_pr__nfet_20v0_iso',
+ 'sky130_fd_pr__nfet_20v0_zvt',
+ 'sky130_fd_pr__nfet_20v0',
+ 'sky130_fd_pr__pfet_20v0',
+ 'sky130_fd_pr__nfet_01v8_lvt',
+ 'sky130_fd_pr__pfet_01v8_mvt',
+ 'sky130_fd_pr__pfet_01v8',
+ 'sky130_fd_pr__nfet_g5v0d16v0',
+ 'sky130_fd_pr__pfet_g5v0d16v0',
+ 'sky130_fd_pr__special_nfet_pass_lvt',
+ 'sky130_fd_pr__pnp_05v5_W0p68L0p68']
+
+# For each entry in the exclude list, create a regular expression
+# for detecting that entry and excluding other similar cases that
+# aren't the parameter. Items with preceding "/" are the device
+# filename, and items with additional text are other parameters.
+
+rexpat = {}
+rexdict = {}
+
+for item in excludelist:
+ rexpat[item] = '([^/])' + item + '(?=[^_])'
+ rexdict[item] = re.compile('([^/])' + item + '(?=[^_])')
+
+#--------------------------------------------------------------------
+
+for infile_name in searchpath:
+ filepath = os.path.split(infile_name)[0]
+ outfile_name = os.path.join(filepath, 'temp')
+
+ infile = open(infile_name, 'r')
+ outfile = open(outfile_name, 'w')
+
+ line_number = 0
+ replaced_something = False
+ for line in infile:
+ line_number += 1
+
+ newline = line
+ for device in excludelist:
+ rmatch = rexdict[device].search(line)
+ if rmatch:
+ replacement = device[14:]
+ newline = re.sub(rexpat[device], '\g<1>' + replacement, newline)
+ replaced_something = True
+
+ outfile.write(newline)
+
+ infile.close()
+ outfile.close()
+ if replaced_something:
+ print("Something was replaced in '{}'".format(infile_name))
+ os.rename(outfile_name, infile_name)
+ else:
+ print("Nothing was replaced in '{}'.".format(infile_name))
+ os.remove(outfile_name)
+
