lemon/mip_glpk.cc
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0:f05cbd89c414 -1:000000000000
     1 /* -*- mode: C++; indent-tabs-mode: nil; -*-
       
     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 extern "C" {
       
    25 #include <glpk.h>
       
    26 }
       
    27 
       
    28 #if GLP_MAJOR_VERSION > 4 || (GLP_MAJOR_VERSION == 4 && GLP_MINOR_VERSION > 15)
       
    29 #define LEMON_glp(func) (glp_##func)
       
    30 #define LEMON_lpx(func) (lpx_##func)
       
    31 
       
    32 #define LEMON_GLP(def) (GLP_##def)
       
    33 #define LEMON_LPX(def) (LPX_##def)
       
    34 
       
    35 #else
       
    36 
       
    37 #define LEMON_glp(func) (lpx_##func)
       
    38 #define LEMON_lpx(func) (lpx_##func)
       
    39 
       
    40 #define LEMON_GLP(def) (LPX_##def)
       
    41 #define LEMON_LPX(def) (LPX_##def)
       
    42 
       
    43 #endif
       
    44 
       
    45 namespace lemon {
       
    46 
       
    47   MipGlpk::MipGlpk() {
       
    48 #if !(GLP_MAJOR_VERSION > 4 || \
       
    49       (GLP_MAJOR_VERSION == 4 && GLP_MINOR_VERSION > 15))
       
    50     LEMON_lpx(set_class)(lp,LEMON_GLP(MIP));
       
    51 #endif
       
    52   }
       
    53 
       
    54   void MipGlpk::_colType(int i, MipGlpk::ColTypes col_type){
       
    55     switch (col_type){
       
    56       case INT:
       
    57         LEMON_glp(set_col_kind)(lp,i,LEMON_GLP(IV));
       
    58         break;
       
    59       case REAL:
       
    60         LEMON_glp(set_col_kind)(lp,i,LEMON_GLP(CV));
       
    61         break;
       
    62     default:;
       
    63         //FIXME problem
       
    64     }
       
    65   }
       
    66 
       
    67   MipGlpk::ColTypes MipGlpk::_colType(int i) const {
       
    68     switch (LEMON_glp(get_col_kind)(lp,i)){
       
    69     case LEMON_GLP(IV):
       
    70       return INT;//Or binary
       
    71     case LEMON_GLP(CV):
       
    72       return REAL;
       
    73     default:
       
    74       return REAL;//Error!
       
    75     }
       
    76 
       
    77   }
       
    78 
       
    79   LpGlpk::SolveExitStatus MipGlpk::_solve() {
       
    80     int result = LEMON_lpx(simplex)(lp);
       
    81 
       
    82     // hack: mip does not contain integer variable
       
    83 #if GLP_MAJOR_VERSION == 4 && GLP_MINOR_VERSION == 16
       
    84     int tmp = -1;
       
    85     if (LEMON_glp(get_num_int(lp)) == 0) {
       
    86       tmp = LEMON_lpx(add_cols)(lp, 1);
       
    87       LEMON_glp(set_col_bnds)(lp, tmp, LEMON_GLP(FX), 0.0, 0.0);
       
    88       LEMON_glp(set_col_kind)(lp, tmp, LEMON_GLP(IV));
       
    89     }
       
    90 #endif
       
    91 
       
    92     if (LEMON_lpx(get_status)(lp)==LEMON_LPX(OPT)) {
       
    93       //Maybe we could try the routine lpx_intopt(lp), a revised
       
    94       //version of lpx_integer
       
    95 
       
    96       result = LEMON_lpx(integer)(lp);
       
    97       switch (result){
       
    98       case LEMON_LPX(E_OK):
       
    99         solved = true;
       
   100         break;
       
   101       default:
       
   102         solved = false;
       
   103       }
       
   104     } else {
       
   105       solved = false;
       
   106     }
       
   107 #if GLP_MAJOR_VERSION == 4 && GLP_MINOR_VERSION == 16
       
   108     if (tmp != -1) {
       
   109       int tmpa[2];
       
   110       tmpa[1] = tmp;
       
   111       LEMON_lpx(del_cols)(lp, 1, tmpa);
       
   112     }
       
   113 #endif
       
   114     return solved ? SOLVED : UNSOLVED;
       
   115   }
       
   116 
       
   117 
       
   118   LpGlpk::SolutionStatus MipGlpk::_getMipStatus() const {
       
   119 
       
   120     if (LEMON_lpx(get_status)(lp)==LEMON_LPX(OPT)){
       
   121       //Meg kell nezni: ha az LP is infinite, akkor ez is, ha az is
       
   122       //infeasible, akkor ez is, de ez lehet maskepp is infeasible.
       
   123       int stat= LEMON_lpx(mip_status)(lp);
       
   124 
       
   125       switch (stat) {
       
   126       case LEMON_LPX(I_UNDEF)://Undefined (no solve has been run yet)
       
   127         return UNDEFINED;
       
   128       case LEMON_LPX(I_NOFEAS)://There is no feasible integral solution
       
   129         return INFEASIBLE;
       
   130         //     case LEMON_LPX(UNBND)://Unbounded
       
   131         //       return INFINITE;
       
   132       case LEMON_LPX(I_FEAS)://Feasible
       
   133         return FEASIBLE;
       
   134       case LEMON_LPX(I_OPT)://Feasible
       
   135         return OPTIMAL;
       
   136       default:
       
   137         return UNDEFINED; //to avoid gcc warning
       
   138       //FIXME error
       
   139       }
       
   140     }
       
   141     else
       
   142       return UNDEFINED; //Maybe we could refine this: what does the LP
       
   143                         //relaxation look like
       
   144 
       
   145   }
       
   146 
       
   147   MipGlpk::Value MipGlpk::_getPrimal(int i) const {
       
   148     return LEMON_glp(mip_col_val)(lp,i);
       
   149   }
       
   150 
       
   151   MipGlpk::Value MipGlpk::_getPrimalValue() const {
       
   152     return LEMON_glp(mip_obj_val)(lp);
       
   153   }
       
   154 } //END OF NAMESPACE LEMON