athos@2219: /* -*- C++ -*-
athos@2219:  *
athos@2219:  * This file is a part of LEMON, a generic C++ optimization library
athos@2219:  *
athos@2219:  * Copyright (C) 2003-2006
athos@2219:  * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
athos@2219:  * (Egervary Research Group on Combinatorial Optimization, EGRES).
athos@2219:  *
athos@2219:  * Permission to use, modify and distribute this software is granted
athos@2219:  * provided that this copyright notice appears in all copies. For
athos@2219:  * precise terms see the accompanying LICENSE file.
athos@2219:  *
athos@2219:  * This software is provided "AS IS" with no warranty of any kind,
athos@2219:  * express or implied, and with no claim as to its suitability for any
athos@2219:  * purpose.
athos@2219:  *
athos@2219:  */
athos@2219: 
athos@2219: ///\file
athos@2219: ///\brief Implementation of the LEMON-CPLEX mip solver interface.
athos@2219: 
athos@2219: #include <lemon/mip_cplex.h>
athos@2219: 
athos@2219: namespace lemon {
athos@2219:   
athos@2219:   MipCplex::MipCplex() {
athos@2219:     //This is unnecessary: setting integrality constraints on
athos@2219:     //variables will set this, too 
athos@2219: 
athos@2219:     ///\todo The constant CPXPROB_MIP is
athos@2219:     ///called CPXPROB_MILP in later versions
athos@2226: #if CPX_VERSION < 800
athos@2219:     CPXchgprobtype( env,  lp, CPXPROB_MIP);
athos@2226: #else
athos@2226:     CPXchgprobtype( env,  lp, CPXPROB_MILP);
athos@2226: #endif
athos@2226: 
athos@2219:   }
athos@2219: 
athos@2219:   void MipCplex::_colType(int i, MipCplex::ColTypes col_type){
athos@2219: 
athos@2219:     // Note If a variable is to be changed to binary, a call to CPXchgbds
athos@2219:     // should also be made to change the bounds to 0 and 1.
athos@2219: 
athos@2219:     int indices[1];
athos@2219:     indices[0]=i;
athos@2219:     char ctype[1];
athos@2219:     switch (col_type){
athos@2267:       case INT:
athos@2219: 	ctype[0]=CPX_INTEGER;//'I'
athos@2219: 	break;
athos@2219:       case REAL:
athos@2219: 	ctype[0]=CPX_CONTINUOUS	;//'C'
athos@2219: 	break;
athos@2219:     default:;
athos@2219:         //FIXME problem
athos@2219:     }
athos@2219:     CPXchgctype (env, lp, 1, indices, ctype);
athos@2219:   }
athos@2219:   
deba@2366:   MipCplex::ColTypes MipCplex::_colType(int i) const {
athos@2219:     
athos@2219:     char ctype[1];
athos@2219:     status = CPXgetctype (env, lp, ctype, i, i);
athos@2219:     switch (ctype[0]){
athos@2219: 
athos@2219:     case CPX_INTEGER:
athos@2267:       return INT;
athos@2219:     case CPX_CONTINUOUS:
athos@2219:       return REAL;
athos@2219:     default:
athos@2219:       return REAL;//Error!
athos@2219:     }
athos@2219: 
athos@2219:   }
athos@2219:   
athos@2219:   LpCplex::SolveExitStatus MipCplex::_solve(){
athos@2219: 
athos@2219:     status = CPXmipopt (env, lp);
athos@2219:     if (status==0)
athos@2219:       return SOLVED;
athos@2219:     else
athos@2219:       return UNSOLVED;
athos@2219: 
athos@2219:   }
athos@2219: 
athos@2219: 
deba@2366:   LpCplex::SolutionStatus MipCplex::_getMipStatus() const {
athos@2219: 
athos@2219:     int stat = CPXgetstat(env, lp);
athos@2219: 
athos@2219:     //Fortunately, MIP statuses did not change for cplex 8.0
athos@2219:     switch (stat)
athos@2219:     {
athos@2219:       case CPXMIP_OPTIMAL:
athos@2219:         return OPTIMAL;
athos@2219: 	//This also exists in later issues
athos@2219: 	//    case CPXMIP_UNBOUNDED:
athos@2219:         //return INFINITE;
athos@2219:       case CPXMIP_INFEASIBLE:
athos@2219:         return INFEASIBLE;
athos@2219:       default:
athos@2219:         return UNDEFINED;
athos@2219:     }
athos@2219:     //Unboundedness not treated well: the following is from cplex 9.0 doc
athos@2219:     // About Unboundedness
athos@2219: 
athos@2219:     // The treatment of models that are unbounded involves a few
athos@2219:     // subtleties. Specifically, a declaration of unboundedness means that
athos@2219:     // ILOG CPLEX has determined that the model has an unbounded
athos@2219:     // ray. Given any feasible solution x with objective z, a multiple of
athos@2219:     // the unbounded ray can be added to x to give a feasible solution
athos@2219:     // with objective z-1 (or z+1 for maximization models). Thus, if a
athos@2219:     // feasible solution exists, then the optimal objective is
athos@2219:     // unbounded. Note that ILOG CPLEX has not necessarily concluded that
athos@2219:     // a feasible solution exists. Users can call the routine CPXsolninfo
athos@2219:     // to determine whether ILOG CPLEX has also concluded that the model
athos@2219:     // has a feasible solution.
athos@2219:       
athos@2219:   }  
athos@2219: 
deba@2366:   MipCplex::Value MipCplex::_getPrimal(int i) const {
athos@2219:     Value x;
athos@2219:     CPXgetmipx(env, lp, &x, i, i);
athos@2219:     return x;
athos@2219:   }
athos@2219:   
deba@2366:   MipCplex::Value MipCplex::_getPrimalValue() const {
athos@2219:     Value objval;
athos@2219:     status = CPXgetmipobjval(env, lp, &objval);
athos@2219:     return objval;
athos@2219:   }
athos@2219: } //END OF NAMESPACE LEMON