deba@458: /* -*- mode: C++; indent-tabs-mode: nil; -*-
deba@458:  *
deba@458:  * This file is a part of LEMON, a generic C++ optimization library.
deba@458:  *
deba@458:  * Copyright (C) 2003-2008
deba@458:  * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
deba@458:  * (Egervary Research Group on Combinatorial Optimization, EGRES).
deba@458:  *
deba@458:  * Permission to use, modify and distribute this software is granted
deba@458:  * provided that this copyright notice appears in all copies. For
deba@458:  * precise terms see the accompanying LICENSE file.
deba@458:  *
deba@458:  * This software is provided "AS IS" with no warranty of any kind,
deba@458:  * express or implied, and with no claim as to its suitability for any
deba@458:  * purpose.
deba@458:  *
deba@458:  */
deba@458: 
deba@458: ///\file
deba@458: ///\brief Implementation of the LEMON-CPLEX mip solver interface.
deba@458: 
deba@458: #include <lemon/mip_cplex.h>
deba@458: 
deba@458: extern "C" {
deba@458: #include <ilcplex/cplex.h>
deba@458: }
deba@458: 
deba@458: namespace lemon {
deba@458: 
deba@458:   MipCplex::MipCplex() {
deba@458:     //This is unnecessary: setting integrality constraints on
deba@458:     //variables will set this, too
deba@458: 
deba@458:     ///\todo The constant CPXPROB_MIP is
deba@458:     ///called CPXPROB_MILP in later versions
deba@458: #if CPX_VERSION < 800
deba@458:     CPXchgprobtype( env,  lp, CPXPROB_MIP);
deba@458: #else
deba@458:     CPXchgprobtype( env,  lp, CPXPROB_MILP);
deba@458: #endif
deba@458: 
deba@458:   }
deba@458: 
deba@458:   void MipCplex::_colType(int i, MipCplex::ColTypes col_type){
deba@458: 
deba@458:     // Note If a variable is to be changed to binary, a call to CPXchgbds
deba@458:     // should also be made to change the bounds to 0 and 1.
deba@458: 
deba@458:     int indices[1];
deba@458:     indices[0]=i;
deba@458:     char ctype[1];
deba@458:     switch (col_type){
deba@458:       case INT:
deba@458:         ctype[0]=CPX_INTEGER;//'I'
deba@458:         break;
deba@458:       case REAL:
deba@458:         ctype[0]=CPX_CONTINUOUS        ;//'C'
deba@458:         break;
deba@458:     default:;
deba@458:         //FIXME problem
deba@458:     }
deba@458:     CPXchgctype (env, lp, 1, indices, ctype);
deba@458:   }
deba@458: 
deba@458:   MipCplex::ColTypes MipCplex::_colType(int i) const {
deba@458: 
deba@458:     char ctype[1];
deba@458:     CPXgetctype (env, lp, ctype, i, i);
deba@458:     switch (ctype[0]){
deba@458: 
deba@458:     case CPX_INTEGER:
deba@458:       return INT;
deba@458:     case CPX_CONTINUOUS:
deba@458:       return REAL;
deba@458:     default:
deba@458:       return REAL;//Error!
deba@458:     }
deba@458: 
deba@458:   }
deba@458: 
deba@458:   LpCplex::SolveExitStatus MipCplex::_solve(){
deba@458: 
deba@458:     status = CPXmipopt (env, lp);
deba@458:     if (status==0)
deba@458:       return SOLVED;
deba@458:     else
deba@458:       return UNSOLVED;
deba@458: 
deba@458:   }
deba@458: 
deba@458: 
deba@458:   LpCplex::SolutionStatus MipCplex::_getMipStatus() const {
deba@458: 
deba@458:     int stat = CPXgetstat(env, lp);
deba@458: 
deba@458:     //Fortunately, MIP statuses did not change for cplex 8.0
deba@458:     switch (stat)
deba@458:     {
deba@458:       case CPXMIP_OPTIMAL:
deba@458:         // Optimal integer solution has been found.
deba@458:       case CPXMIP_OPTIMAL_TOL:
deba@458:         // Optimal soluton with the tolerance defined by epgap or epagap has
deba@458:         // been found.
deba@458:         return OPTIMAL;
deba@458:         //This also exists in later issues
deba@458:         //    case CPXMIP_UNBOUNDED:
deba@458:         //return INFINITE;
deba@458:       case CPXMIP_INFEASIBLE:
deba@458:         return INFEASIBLE;
deba@458:       default:
deba@458:         return UNDEFINED;
deba@458:     }
deba@458:     //Unboundedness not treated well: the following is from cplex 9.0 doc
deba@458:     // About Unboundedness
deba@458: 
deba@458:     // The treatment of models that are unbounded involves a few
deba@458:     // subtleties. Specifically, a declaration of unboundedness means that
deba@458:     // ILOG CPLEX has determined that the model has an unbounded
deba@458:     // ray. Given any feasible solution x with objective z, a multiple of
deba@458:     // the unbounded ray can be added to x to give a feasible solution
deba@458:     // with objective z-1 (or z+1 for maximization models). Thus, if a
deba@458:     // feasible solution exists, then the optimal objective is
deba@458:     // unbounded. Note that ILOG CPLEX has not necessarily concluded that
deba@458:     // a feasible solution exists. Users can call the routine CPXsolninfo
deba@458:     // to determine whether ILOG CPLEX has also concluded that the model
deba@458:     // has a feasible solution.
deba@458: 
deba@458:   }
deba@458: 
deba@458:   MipCplex::Value MipCplex::_getPrimal(int i) const {
deba@458:     Value x;
deba@458:     CPXgetmipx(env, lp, &x, i, i);
deba@458:     return x;
deba@458:   }
deba@458: 
deba@458:   MipCplex::Value MipCplex::_getPrimalValue() const {
deba@458:     Value objval;
deba@458:     CPXgetmipobjval(env, lp, &objval);
deba@458:     return objval;
deba@458:   }
deba@458: } //END OF NAMESPACE LEMON