COIN-OR::LEMON - Graph Library

source: lemon-0.x/test/mip_test.cc @ 2553:bfced05fa852

Last change on this file since 2553:bfced05fa852 was 2553:bfced05fa852, checked in by Alpar Juttner, 12 years ago

Happy New Year to LEMON (+ better update-copyright-header script)

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1/* -*- C++ -*-
2 *
3 * This file is a part of LEMON, a generic C++ optimization library
4 *
5 * Copyright (C) 2003-2008
6 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
7 * (Egervary Research Group on Combinatorial Optimization, EGRES).
8 *
9 * Permission to use, modify and distribute this software is granted
10 * provided that this copyright notice appears in all copies. For
11 * precise terms see the accompanying LICENSE file.
12 *
13 * This software is provided "AS IS" with no warranty of any kind,
14 * express or implied, and with no claim as to its suitability for any
15 * purpose.
16 *
17 */
18
19#include "test_tools.h"
20
21
22#ifdef HAVE_CONFIG_H
23#include <config.h>
24#endif
25
26#ifdef HAVE_CPLEX
27#include <lemon/mip_cplex.h>
28#endif
29
30#ifdef HAVE_GLPK
31#include <lemon/mip_glpk.h>
32#endif
33
34
35using namespace lemon;
36
37void solveAndCheck(MipSolverBase& lp, MipSolverBase::SolutionStatus stat,
38                   double exp_opt) {
39  using std::string;
40
41  lp.solve();
42  //int decimal,sign;
43  std::ostringstream buf;
44  buf << "Primalstatus should be: " << int(stat)<<" and it is "<<int(lp.mipStatus());
45
46
47  //  itoa(stat,buf1, 10);
48  check(lp.mipStatus()==stat, buf.str());
49
50  if (stat ==  MipSolverBase::OPTIMAL) {
51    std::ostringstream sbuf;
52    buf << "Wrong optimal value: the right optimum is " << exp_opt;
53    check(std::abs(lp.primalValue()-exp_opt) < 1e-3, sbuf.str());
54    //+ecvt(exp_opt,2)
55  }
56}
57
58void aTest(MipSolverBase& mip)
59{
60 //The following example is very simple
61
62
63  typedef MipSolverBase::Row Row;
64  typedef MipSolverBase::Col Col;
65
66
67
68  Col x1 = mip.addCol();
69  Col x2 = mip.addCol();
70
71
72  //Objective function
73  mip.obj(x1);
74
75  mip.max();
76
77
78  //Unconstrained optimization
79  mip.solve();
80  //Check it out!
81
82  //Constraints
83  mip.addRow(2*x1+x2 <=2); 
84  mip.addRow(x1-2*x2 <=0);
85
86  //Nonnegativity of the variable x1
87  mip.colLowerBound(x1, 0);
88
89  //Maximization of x1
90  //over the triangle with vertices (0,0),(4/5,2/5),(0,2)
91  double expected_opt=4.0/5.0;
92  solveAndCheck(mip, MipSolverBase::OPTIMAL, expected_opt);
93
94  //Restrict x2 to integer
95  mip.colType(x2,MipSolverBase::INT); 
96  expected_opt=1.0/2.0;
97  solveAndCheck(mip, MipSolverBase::OPTIMAL, expected_opt);
98
99
100  //Restrict both to integer
101  mip.colType(x1,MipSolverBase::INT); 
102  expected_opt=0;
103  solveAndCheck(mip, MipSolverBase::OPTIMAL, expected_opt);
104
105 
106
107}
108
109
110int main()
111{
112
113#ifdef HAVE_GLPK
114  MipGlpk mip1;
115  aTest(mip1);
116#endif
117
118#ifdef HAVE_CPLEX
119  MipCplex mip2;
120  aTest(mip2);
121#endif
122
123  return 0;
124
125}
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