COIN-OR::LEMON - Graph Library

source: lemon-0.x/lemon/mip_glpk.cc

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

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

File size: 3.8 KB
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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///\file
20///\brief Implementation of the LEMON-GLPK mip solver interface.
21
22#include <lemon/mip_glpk.h>
23
24#if GLP_MAJOR_VERSION > 4 || (GLP_MAJOR_VERSION == 4 && GLP_MINOR_VERSION > 15)
25#define LEMON_glp(func) (glp_##func)
26#define LEMON_lpx(func) (lpx_##func)
27
28#define LEMON_GLP(def) (GLP_##def)
29#define LEMON_LPX(def) (LPX_##def)
30
31#else
32
33#define LEMON_glp(func) (lpx_##func)
34#define LEMON_lpx(func) (lpx_##func)
35
36#define LEMON_GLP(def) (LPX_##def)
37#define LEMON_LPX(def) (LPX_##def)
38
39#endif
40
41namespace lemon {
42 
43  MipGlpk::MipGlpk() {
44#if !(GLP_MAJOR_VERSION > 4 || (GLP_MAJOR_VERSION == 4 && GLP_MINOR_VERSION > 15))
45    LEMON_lpx(set_class)(lp,LEMON_GLP(MIP));
46#endif
47  }
48
49  void MipGlpk::_colType(int i, MipGlpk::ColTypes col_type){
50    switch (col_type){
51      case INT:
52        LEMON_glp(set_col_kind)(lp,i,LEMON_GLP(IV));
53        break;
54      case REAL:
55        LEMON_glp(set_col_kind)(lp,i,LEMON_GLP(CV));
56        break;
57    default:;
58        //FIXME problem
59    }
60  }
61 
62  MipGlpk::ColTypes MipGlpk::_colType(int i) const {
63    switch (LEMON_glp(get_col_kind)(lp,i)){
64    case LEMON_GLP(IV):
65      return INT;//Or binary
66    case LEMON_GLP(CV):
67      return REAL;
68    default:
69      return REAL;//Error!
70    }
71   
72  }
73 
74  LpGlpk::SolveExitStatus MipGlpk::_solve() {
75    int result = LEMON_lpx(simplex)(lp);
76
77    // hack: mip does not contain integer variable
78#if GLP_MAJOR_VERSION == 4 && GLP_MINOR_VERSION == 16
79    int tmp = -1;
80    if (LEMON_glp(get_num_int(lp)) == 0) {
81      tmp = LEMON_lpx(add_cols)(lp, 1);
82      LEMON_glp(set_col_bnds)(lp, tmp, LEMON_GLP(FX), 0.0, 0.0);
83      LEMON_glp(set_col_kind)(lp, tmp, LEMON_GLP(IV));
84    }
85#endif
86
87    if (LEMON_lpx(get_status)(lp)==LEMON_LPX(OPT)) {
88      //Maybe we could try the routine lpx_intopt(lp), a revised
89      //version of lpx_integer
90
91      result = LEMON_lpx(integer)(lp);
92      switch (result){
93      case LEMON_LPX(E_OK):
94        solved = true;
95        break;
96      default:
97        solved = false;
98      } 
99    } else {
100      solved = false;
101    }
102#if GLP_MAJOR_VERSION == 4 && GLP_MINOR_VERSION == 16
103    if (tmp != -1) {
104      int tmpa[2];
105      tmpa[1] = tmp;
106      LEMON_lpx(del_cols)(lp, 1, tmpa);
107    }
108#endif
109    return solved ? SOLVED : UNSOLVED;
110  }
111
112
113  LpGlpk::SolutionStatus MipGlpk::_getMipStatus() const {
114
115    if (LEMON_lpx(get_status)(lp)==LEMON_LPX(OPT)){
116      //Meg kell nezni: ha az LP is infinite, akkor ez is, ha az is
117      //infeasible, akkor ez is, de ez lehet maskepp is infeasible.
118      int stat= LEMON_lpx(mip_status)(lp);
119     
120      switch (stat) {
121      case LEMON_LPX(I_UNDEF)://Undefined (no solve has been run yet)
122        return UNDEFINED;
123      case LEMON_LPX(I_NOFEAS)://There is no feasible integral solution
124        return INFEASIBLE;
125        //     case LEMON_LPX(UNBND)://Unbounded
126        //       return INFINITE;
127      case LEMON_LPX(I_FEAS)://Feasible
128        return FEASIBLE;
129      case LEMON_LPX(I_OPT)://Feasible
130        return OPTIMAL;
131      default:
132        return UNDEFINED; //to avoid gcc warning
133      //FIXME error
134      }
135    }
136    else
137      return UNDEFINED; //Maybe we could refine this: what does the LP
138                        //relaxation look like
139     
140  } 
141
142  MipGlpk::Value MipGlpk::_getPrimal(int i) const {
143    return LEMON_glp(mip_col_val)(lp,i);
144  }
145 
146  MipGlpk::Value MipGlpk::_getPrimalValue() const {
147    return LEMON_glp(mip_obj_val)(lp);
148  }
149} //END OF NAMESPACE LEMON
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