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1 /* -*- mode: C++; indent-tabs-mode: nil; -*- |
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2 * |
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3 * This file is a part of LEMON, a generic C++ optimization library. |
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4 * |
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5 * Copyright (C) 2003-2008 |
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6 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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7 * (Egervary Research Group on Combinatorial Optimization, EGRES). |
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8 * |
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9 * Permission to use, modify and distribute this software is granted |
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10 * provided that this copyright notice appears in all copies. For |
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11 * precise terms see the accompanying LICENSE file. |
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12 * |
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13 * This software is provided "AS IS" with no warranty of any kind, |
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14 * express or implied, and with no claim as to its suitability for any |
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15 * purpose. |
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16 * |
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17 */ |
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18 |
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19 ///\file |
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20 ///\brief Implementation of the LEMON-GLPK mip solver interface. |
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21 |
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22 #include <lemon/mip_glpk.h> |
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23 |
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24 extern "C" { |
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25 #include <glpk.h> |
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26 } |
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27 |
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28 #if GLP_MAJOR_VERSION > 4 || (GLP_MAJOR_VERSION == 4 && GLP_MINOR_VERSION > 15) |
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29 #define LEMON_glp(func) (glp_##func) |
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30 #define LEMON_lpx(func) (lpx_##func) |
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31 |
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32 #define LEMON_GLP(def) (GLP_##def) |
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33 #define LEMON_LPX(def) (LPX_##def) |
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34 |
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35 #else |
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36 |
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37 #define LEMON_glp(func) (lpx_##func) |
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38 #define LEMON_lpx(func) (lpx_##func) |
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39 |
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40 #define LEMON_GLP(def) (LPX_##def) |
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41 #define LEMON_LPX(def) (LPX_##def) |
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42 |
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43 #endif |
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44 |
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45 namespace lemon { |
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46 |
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47 MipGlpk::MipGlpk() { |
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48 #if !(GLP_MAJOR_VERSION > 4 || \ |
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49 (GLP_MAJOR_VERSION == 4 && GLP_MINOR_VERSION > 15)) |
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50 LEMON_lpx(set_class)(lp,LEMON_GLP(MIP)); |
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51 #endif |
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52 } |
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53 |
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54 void MipGlpk::_colType(int i, MipGlpk::ColTypes col_type){ |
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55 switch (col_type){ |
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56 case INT: |
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57 LEMON_glp(set_col_kind)(lp,i,LEMON_GLP(IV)); |
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58 break; |
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59 case REAL: |
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60 LEMON_glp(set_col_kind)(lp,i,LEMON_GLP(CV)); |
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61 break; |
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62 default:; |
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63 //FIXME problem |
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64 } |
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65 } |
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66 |
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67 MipGlpk::ColTypes MipGlpk::_colType(int i) const { |
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68 switch (LEMON_glp(get_col_kind)(lp,i)){ |
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69 case LEMON_GLP(IV): |
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70 return INT;//Or binary |
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71 case LEMON_GLP(CV): |
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72 return REAL; |
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73 default: |
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74 return REAL;//Error! |
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75 } |
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76 |
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77 } |
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78 |
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79 LpGlpk::SolveExitStatus MipGlpk::_solve() { |
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80 int result = LEMON_lpx(simplex)(lp); |
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81 |
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82 // hack: mip does not contain integer variable |
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83 #if GLP_MAJOR_VERSION == 4 && GLP_MINOR_VERSION == 16 |
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84 int tmp = -1; |
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85 if (LEMON_glp(get_num_int(lp)) == 0) { |
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86 tmp = LEMON_lpx(add_cols)(lp, 1); |
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87 LEMON_glp(set_col_bnds)(lp, tmp, LEMON_GLP(FX), 0.0, 0.0); |
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88 LEMON_glp(set_col_kind)(lp, tmp, LEMON_GLP(IV)); |
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89 } |
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90 #endif |
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91 |
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92 if (LEMON_lpx(get_status)(lp)==LEMON_LPX(OPT)) { |
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93 //Maybe we could try the routine lpx_intopt(lp), a revised |
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94 //version of lpx_integer |
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95 |
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96 result = LEMON_lpx(integer)(lp); |
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97 switch (result){ |
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98 case LEMON_LPX(E_OK): |
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99 solved = true; |
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100 break; |
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101 default: |
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102 solved = false; |
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103 } |
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104 } else { |
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105 solved = false; |
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106 } |
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107 #if GLP_MAJOR_VERSION == 4 && GLP_MINOR_VERSION == 16 |
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108 if (tmp != -1) { |
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109 int tmpa[2]; |
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110 tmpa[1] = tmp; |
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111 LEMON_lpx(del_cols)(lp, 1, tmpa); |
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112 } |
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113 #endif |
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114 return solved ? SOLVED : UNSOLVED; |
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115 } |
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116 |
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117 |
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118 LpGlpk::SolutionStatus MipGlpk::_getMipStatus() const { |
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119 |
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120 if (LEMON_lpx(get_status)(lp)==LEMON_LPX(OPT)){ |
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121 //Meg kell nezni: ha az LP is infinite, akkor ez is, ha az is |
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122 //infeasible, akkor ez is, de ez lehet maskepp is infeasible. |
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123 int stat= LEMON_lpx(mip_status)(lp); |
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124 |
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125 switch (stat) { |
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126 case LEMON_LPX(I_UNDEF)://Undefined (no solve has been run yet) |
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127 return UNDEFINED; |
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128 case LEMON_LPX(I_NOFEAS)://There is no feasible integral solution |
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129 return INFEASIBLE; |
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130 // case LEMON_LPX(UNBND)://Unbounded |
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131 // return INFINITE; |
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132 case LEMON_LPX(I_FEAS)://Feasible |
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133 return FEASIBLE; |
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134 case LEMON_LPX(I_OPT)://Feasible |
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135 return OPTIMAL; |
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136 default: |
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137 return UNDEFINED; //to avoid gcc warning |
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138 //FIXME error |
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139 } |
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140 } |
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141 else |
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142 return UNDEFINED; //Maybe we could refine this: what does the LP |
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143 //relaxation look like |
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144 |
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145 } |
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146 |
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147 MipGlpk::Value MipGlpk::_getPrimal(int i) const { |
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148 return LEMON_glp(mip_col_val)(lp,i); |
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149 } |
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150 |
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151 MipGlpk::Value MipGlpk::_getPrimalValue() const { |
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152 return LEMON_glp(mip_obj_val)(lp); |
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153 } |
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154 } //END OF NAMESPACE LEMON |