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lemon/mip_glpk.cc
author alpar
Tue, 13 Mar 2007 16:32:35 +0000
changeset 2409 fe0a8fe16271
parent 2366 bfbdded3763a
child 2441 d8d6ab871608
permissions -rw-r--r--
Minimum mean cycle algorithm contributed by Peter Kovacs. 
     1 /* -*- C++ -*-

     2  *

     3  * This file is a part of LEMON, a generic C++ optimization library

     4  *

     5  * Copyright (C) 2003-2007

     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 namespace lemon {

    25   

    26   MipGlpk::MipGlpk() {

    27     lpx_set_class(lp,LPX_MIP);

    28   }

    29 

    30   void MipGlpk::_colType(int i, MipGlpk::ColTypes col_type){

    31     switch (col_type){

    32       case INT:

    33 	lpx_set_col_kind(lp,i,LPX_IV);

    34 	break;

    35       case REAL:

    36 	lpx_set_col_kind(lp,i,LPX_CV);

    37 	break;

    38     default:;

    39         //FIXME problem

    40     }

    41   }

    42   

    43   MipGlpk::ColTypes MipGlpk::_colType(int i) const {

    44     switch (lpx_get_col_kind(lp,i)){

    45     case LPX_IV:

    46       return INT;//Or binary

    47     case LPX_CV:

    48       return REAL;

    49     default:

    50       return REAL;//Error!

    51     }

    52     

    53   }

    54   

    55   LpGlpk::SolveExitStatus MipGlpk::_solve() {

    56     int result = lpx_simplex(lp);

    57     //

    58     if (lpx_get_status(lp)==LPX_OPT){

    59       //Maybe we could try the routine lpx_intopt(lp), a revised

    60       //version of lpx_integer

    61       result = lpx_integer(lp);

    62       switch (result){

    63       case LPX_E_OK:

    64 	return SOLVED;

    65       default:

    66 	return UNSOLVED;

    67       }

    68       

    69     }

    70     return UNSOLVED;

    71   }

    72 

    73 

    74   LpGlpk::SolutionStatus MipGlpk::_getMipStatus() const {

    75 

    76     if (lpx_get_status(lp)==LPX_OPT){

    77       //Meg kell nezni: ha az LP is infinite, akkor ez is, ha az is

    78       //infeasible, akkor ez is, de ez lehet maskepp is infeasible.

    79       int stat=  lpx_mip_status(lp);

    80       

    81       switch (stat) {

    82       case LPX_I_UNDEF://Undefined (no solve has been run yet)

    83 	return UNDEFINED;

    84       case LPX_I_NOFEAS://There is no feasible integral solution

    85 	return INFEASIBLE;

    86 	//     case LPX_UNBND://Unbounded

    87 	//       return INFINITE;

    88       case LPX_I_FEAS://Feasible

    89 	return FEASIBLE;

    90       case LPX_I_OPT://Feasible

    91 	return OPTIMAL;

    92       default:

    93       return UNDEFINED; //to avoid gcc warning

    94       //FIXME error

    95       }

    96     }

    97     else 

    98       return UNDEFINED; //Maybe we could refine this: what does the LP

    99 			//relaxation look like

   100       

   101   }  

   102 

   103   MipGlpk::Value MipGlpk::_getPrimal(int i) const {

   104     return lpx_mip_col_val(lp,i);

   105   }

   106   

   107   MipGlpk::Value MipGlpk::_getPrimalValue() const {

   108     return lpx_mip_obj_val(lp);

   109   }

   110 } //END OF NAMESPACE LEMON
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