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#!/usr/bin/env python3
import sys
import re
import os
import tempfile
from gurobipy import *
if len(sys.argv) < 2:
print('Usage: gurobi.sh checkcuts.py filename [cutnamefilter]')
quit()
filename = sys.argv[1]
cutclassname = ""
if len(sys.argv) == 3:
cutclassname = sys.argv[2]
base=os.path.basename(filename)
prefix=os.path.splitext(base)[0]
basemodelname=prefix + "_withoutcuts.lp"
lazyconss = None
with open (filename, "r") as myfile:
data=myfile.readlines()
lazyconsstart = data.index("lazy constraints\n")
boundstart = data.index("Bounds\n")
lines1 = data[:lazyconsstart]
lines2 = data[boundstart:]
lazyconss = data[lazyconsstart+1:boundstart]
with open(basemodelname, "w") as outfile:
for line in lines1:
outfile.write(line)
for line in lines2:
outfile.write(line)
model = read(basemodelname)
os.remove(basemodelname)
model.setParam("OutputFlag", 0);
model.setParam("FeasibilityTol", 1e-9)
validcuts = 0
invalidcuts = 0
currcons = ""
for lazycons in lazyconss:
currcons += lazycons
m = re.match("([^:]*):([^<]*)(<=|>=)([^\n]*)", currcons)
if m is None:
currcons = currcons[:-1]
continue
currcons=""
consname = m.group(1).strip()
if not cutclassname in consname:
continue
cons = m.group(2).strip()
rhs = float(m.group(4).strip())
if m.group(3) == "<=":
objsense = GRB.MAXIMIZE
else:
objsense = GRB.MINIMIZE
objexpr = LinExpr()
while len(cons) > 0:
m = re.match("[\+-][0-9][^ ]*[^\+-]*", cons)
length = len(m.group(0))
term = m.group(0).strip()
coef,varname = term.split()
cons = cons[length:]
var = model.getVarByName(varname)
objexpr.add(var, float(coef))
model.setObjective(objexpr, objsense)
model.optimize()
if model.status == GRB.Status.INF_OR_UNBD:
print("\nError: model is infeasible or unbounded")
quit()
viol = model.objVal - rhs
if viol > 1e-9:
solname = prefix + "_" + consname + ".sol"
modelfilename = prefix + "_" + consname + ".lp"
model.write(solname)
model.write(modelfilename)
print("cut " + consname + " is invalid!")
print("\tmodel to verify cut has been written to " + modelfilename)
print("\tinteger solution that violates the cut by "+ str(viol) + " was written to " + solname)
invalidcuts += 1
else:
validcuts += 1
print("found "+str(invalidcuts)+" invalid and "+str(validcuts) + " valid cuts")
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