by Nihat Engin Toklu, 2015.
Gurowankenobi is a C++ interface for GLPK (GNU Linear Programming Kit). The C++ interface provided by Gurowankenobi is a compatible subset of the C++ interface of the commercial Gurobi solver.
By using Gurowankenobi, the programs which were previously written in a Gurobi-dependent way will have the option to be compiled for working with GLPK as well.
Instead of the header files of Gurobi, you just include the header file of Gurowankenobi:
#include "gurowan.hpp"You do not have to link your program with GLPK. If GLPK is installed and the executable glpsol is on the PATH environment variable, the optimize() function of gurowankenobi library will generate the model in a temporary file, execute a GLPK process which will load the model from that temporary file, and then read the results from the standard output of the GLPK solver.
The following C++ code works:
#include <iostream>
#include <string>
#include "gurowan.hpp"
int main()
{
GRBEnv env;
GRBModel model(env);
// set the model sense (minimization or maximization)
model.set(GRB_IntAttr_ModelSense, GRB_MINIMIZE);
// add variables to the model
//GRBVar varname = model.addVar(lowerBound, upperBound,
// coefficientInObjFunc, varType, varnameAsString);
GRBVar x1 = model.addVar(0, 100, 1, GRB_CONTINUOUS, "x1");
GRBVar x2 = model.addVar(0, 100, 1, GRB_CONTINUOUS, "x2");
GRBVar x3 = model.addVar(0, 2, 0, GRB_INTEGER, "x3");
// actually updating is not necessary in gurowankenobi
// the following line is for compatibility
model.update();
// add the constraint Constr1: 6*x2-3*x1 <= 20-x3
model.addConstr(6 * x2 - 3 * x1 <= 20 - x3, "Constr1");
std::cout << "num. of vars: "
<< model.get(GRB_IntAttr_NumVars) << std::endl;
std::cout << "num. of constrs: "
<< model.get(GRB_IntAttr_NumConstrs) << std::endl;
std::cout << std::endl;
// solve the model
model.optimize();
// show the results
std::cout << "REPORTING RESULTS:" << std::endl;
std::cout << "x1:" << x1.get(GRB_DoubleAttr_X) << std::endl;
std::cout << "x2:" << x2.get(GRB_DoubleAttr_X) << std::endl;
std::cout << "x3:" << x3.get(GRB_DoubleAttr_X) << std::endl;
std::cout << "objective:" << model.get(GRB_DoubleAttr_ObjVal) << std::endl;
int status;
status = model.get(GRB_IntAttr_Status);
std::cout << "status:" << status << std::endl;
if (status == GRB_OPTIMAL)
{
std::cout << "It's optimal!" << std::endl;
}
return 0;
}Gurowankenobi is free/open-source software. Licensing details are as follows:
Copyright (c) 2015 Nihat Engin Toklu < http://github.com/engintoklu >
Boost Software License - Version 1.0 - August 17, 2003
Permission is hereby granted, free of charge, to any person or organization
obtaining a copy of the software and accompanying documentation covered by
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Software, and to permit third-parties to whom the Software is furnished to
do so, all subject to the following:
The copyright notices in the Software and this entire statement, including
the above license grant, this restriction and the following disclaimer,
must be included in all copies of the Software, in whole or in part, and
all derivative works of the Software, unless such copies or derivative
works are solely in the form of machine-executable object code generated by
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
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