lp.py
#!/usr/bin/env python3.7 # Copyright 2021, Gurobi Optimization, LLC # This example reads an LP model from a file and solves it. # If the model is infeasible or unbounded, the example turns off # presolve and solves the model again. If the model is infeasible, # the example computes an Irreducible Inconsistent Subsystem (IIS), # and writes it to a file import sys import gurobipy as gp from gurobipy import GRB if len(sys.argv) < 2: print('Usage: lp.py filename') sys.exit(0) # Read and solve model model = gp.read(sys.argv[1]) model.optimize() if model.status == GRB.INF_OR_UNBD: # Turn presolve off to determine whether model is infeasible # or unbounded model.setParam(GRB.Param.Presolve, 0) model.optimize() if model.status == GRB.OPTIMAL: print('Optimal objective: %g' % model.objVal) model.write('model.sol') sys.exit(0) elif model.status != GRB.INFEASIBLE: print('Optimization was stopped with status %d' % model.status) sys.exit(0) # Model is infeasible - compute an Irreducible Inconsistent Subsystem (IIS) print('') print('Model is infeasible') model.computeIIS() model.write("model.ilp") print("IIS written to file 'model.ilp'")
