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/* -*- C++ -*-
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*
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* This file is a part of LEMON, a generic C++ optimization library
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*
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* Copyright (C) 2003-2006
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* Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
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* (Egervary Research Group on Combinatorial Optimization, EGRES).
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*
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* Permission to use, modify and distribute this software is granted
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* provided that this copyright notice appears in all copies. For
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* precise terms see the accompanying LICENSE file.
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*
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* This software is provided "AS IS" with no warranty of any kind,
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* express or implied, and with no claim as to its suitability for any
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* purpose.
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*
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*/
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///\file
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///\brief Implementation of the LEMON-GLPK mip solver interface.
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#include <lemon/mip_glpk.h>
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namespace lemon {
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MipGlpk::MipGlpk() {
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lpx_set_class(lp,LPX_MIP);
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}
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void MipGlpk::_colType(int i, MipGlpk::ColTypes col_type){
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switch (col_type){
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case INT:
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lpx_set_col_kind(lp,i,LPX_IV);
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break;
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case REAL:
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lpx_set_col_kind(lp,i,LPX_CV);
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break;
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default:;
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//FIXME problem
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}
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}
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MipGlpk::ColTypes MipGlpk::_colType(int i){
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switch (lpx_get_col_kind(lp,i)){
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case LPX_IV:
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return INT;//Or binary
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case LPX_CV:
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return REAL;
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default:
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return REAL;//Error!
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}
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}
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LpGlpk::SolveExitStatus MipGlpk::_solve(){
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int result = lpx_simplex(lp);
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//
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if (lpx_get_status(lp)==LPX_OPT){
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//Maybe we could try the routine lpx_intopt(lp), a revised
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//version of lpx_integer
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result = lpx_integer(lp);
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switch (result){
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case LPX_E_OK:
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return SOLVED;
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default:
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return UNSOLVED;
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}
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}
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return UNSOLVED;
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}
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LpGlpk::SolutionStatus MipGlpk::_getMipStatus(){
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if (lpx_get_status(lp)==LPX_OPT){
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//Meg kell nezni: ha az LP is infinite, akkor ez is, ha az is
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//infeasible, akkor ez is, de ez lehet maskepp is infeasible.
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int stat= lpx_mip_status(lp);
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switch (stat) {
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case LPX_I_UNDEF://Undefined (no solve has been run yet)
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return UNDEFINED;
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case LPX_I_NOFEAS://There is no feasible integral solution
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return INFEASIBLE;
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// case LPX_UNBND://Unbounded
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// return INFINITE;
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case LPX_I_FEAS://Feasible
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return FEASIBLE;
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case LPX_I_OPT://Feasible
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return OPTIMAL;
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default:
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return UNDEFINED; //to avoid gcc warning
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//FIXME error
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}
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}
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else
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return UNDEFINED; //Maybe we could refine this: what does the LP
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//relaxation look like
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}
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MipGlpk::Value MipGlpk::_getPrimal(int i){
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return lpx_mip_col_val(lp,i);
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}
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MipGlpk::Value MipGlpk::_getPrimalValue(){
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return lpx_mip_obj_val(lp);
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}
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} //END OF NAMESPACE LEMON
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