kpeter@54: /* -*- mode: C++; indent-tabs-mode: nil; -*-
kpeter@54:  *
kpeter@54:  * This file is a part of LEMON, a generic C++ optimization library.
kpeter@54:  *
kpeter@54:  * Copyright (C) 2003-2010
kpeter@54:  * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
kpeter@54:  * (Egervary Research Group on Combinatorial Optimization, EGRES).
kpeter@54:  *
kpeter@54:  * Permission to use, modify and distribute this software is granted
kpeter@54:  * provided that this copyright notice appears in all copies. For
kpeter@54:  * precise terms see the accompanying LICENSE file.
kpeter@54:  *
kpeter@54:  * This software is provided "AS IS" with no warranty of any kind,
kpeter@54:  * express or implied, and with no claim as to its suitability for any
kpeter@54:  * purpose.
kpeter@54:  *
kpeter@54:  */
kpeter@54: 
kpeter@54: ///\file
kpeter@54: ///\brief Demo program for the MIP solver interface.
kpeter@54: ///
kpeter@54: /// This demo program shows how the LEMON MIP solver interface can be used.
kpeter@54: /// A simple mixed integer programming (MIP) problem is formulated and solved
kpeter@54: /// using the default MIP solver (e.g. GLPK).
kpeter@54: ///
kpeter@54: /// \include mip_demo.cc
kpeter@54: 
kpeter@54: #include <iostream>
kpeter@54: #include <lemon/lp.h>
kpeter@54: 
kpeter@54: using namespace lemon;
kpeter@54: 
kpeter@54: int main()
kpeter@54: {
kpeter@54:   // Create an instance of the default MIP solver class
kpeter@54:   // (it will represent an "empty" problem at first)
kpeter@54:   Mip mip;
kpeter@54: 
kpeter@54:   // Add two columns (variables) to the problem
kpeter@54:   Mip::Col x1 = mip.addCol();
kpeter@54:   Mip::Col x2 = mip.addCol();
kpeter@54: 
kpeter@54:   // Add rows (constraints) to the problem
kpeter@54:   mip.addRow(x1 - 5 <= x2);
kpeter@54:   mip.addRow(0 <= 2 * x1 + x2 <= 25);
kpeter@54:   
kpeter@54:   // Set lower and upper bounds for the columns (variables)
kpeter@54:   mip.colLowerBound(x1, 0);
kpeter@54:   mip.colUpperBound(x2, 10);
kpeter@54:   
kpeter@54:   // Set the type of the columns
kpeter@54:   mip.colType(x1, Mip::INTEGER);
kpeter@54:   mip.colType(x2, Mip::REAL);
kpeter@54:   
kpeter@54:   // Specify the objective function
kpeter@54:   mip.max();
kpeter@54:   mip.obj(5 * x1 + 3 * x2);
kpeter@54:   
kpeter@54:   // Solve the problem using the underlying MIP solver
kpeter@54:   mip.solve();
kpeter@54: 
kpeter@54:   // Print the results
kpeter@54:   if (mip.type() == Mip::OPTIMAL) {
kpeter@54:     std::cout << "Objective function value: " << mip.solValue() << std::endl;
kpeter@54:     std::cout << "x1 = " << mip.sol(x1) << std::endl;
kpeter@54:     std::cout << "x2 = " << mip.sol(x2) << std::endl;
kpeter@54:   } else {
kpeter@54:     std::cout << "Optimal solution not found." << std::endl;
kpeter@54:   }
kpeter@54: 
kpeter@54:   return 0;
kpeter@54: }