/* -*- C++ -*-

  *

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

  *

  * Copyright (C) 2003-2008

  * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport

  * (Egervary Research Group on Combinatorial Optimization, EGRES).

  *

  * Permission to use, modify and distribute this software is granted

  * provided that this copyright notice appears in all copies. For

  * precise terms see the accompanying LICENSE file.

  *

  * This software is provided "AS IS" with no warranty of any kind,

  * express or implied, and with no claim as to its suitability for any

  * purpose.

  *

  */

 ///\file

 ///\brief Implementation of the LEMON-CPLEX mip solver interface.

 #include <lemon/mip_cplex.h>

 namespace lemon {

   MipCplex::MipCplex() {

     //This is unnecessary: setting integrality constraints on

     //variables will set this, too 

     ///\todo The constant CPXPROB_MIP is

     ///called CPXPROB_MILP in later versions

 #if CPX_VERSION < 800

     CPXchgprobtype( env,  lp, CPXPROB_MIP);

 #else

     CPXchgprobtype( env,  lp, CPXPROB_MILP);

 #endif

   }

   void MipCplex::_colType(int i, MipCplex::ColTypes col_type){

     // Note If a variable is to be changed to binary, a call to CPXchgbds

     // should also be made to change the bounds to 0 and 1.

     int indices[1];

     indices[0]=i;

     char ctype[1];

     switch (col_type){

       case INT:

 	ctype[0]=CPX_INTEGER;//'I'

 	break;

       case REAL:

 	ctype[0]=CPX_CONTINUOUS	;//'C'

 	break;

     default:;

         //FIXME problem

     }

     CPXchgctype (env, lp, 1, indices, ctype);

   }

   MipCplex::ColTypes MipCplex::_colType(int i) const {

     char ctype[1];

     CPXgetctype (env, lp, ctype, i, i);

     switch (ctype[0]){

     case CPX_INTEGER:

       return INT;

     case CPX_CONTINUOUS:

       return REAL;

     default:

       return REAL;//Error!

     }

   }

   LpCplex::SolveExitStatus MipCplex::_solve(){

     status = CPXmipopt (env, lp);

     if (status==0)

       return SOLVED;

     else

       return UNSOLVED;

   }

   LpCplex::SolutionStatus MipCplex::_getMipStatus() const {

     int stat = CPXgetstat(env, lp);

     //Fortunately, MIP statuses did not change for cplex 8.0

     switch (stat)

     {

       case CPXMIP_OPTIMAL:

         // Optimal integer solution has been found.

       case CPXMIP_OPTIMAL_TOL:

         // Optimal soluton with the tolerance defined by epgap or epagap has 

         // been found.

         return OPTIMAL;

 	//This also exists in later issues

 	//    case CPXMIP_UNBOUNDED:

         //return INFINITE;

       case CPXMIP_INFEASIBLE:

         return INFEASIBLE;

       default:

         return UNDEFINED;

     }

     //Unboundedness not treated well: the following is from cplex 9.0 doc

     // About Unboundedness

     // The treatment of models that are unbounded involves a few

     // subtleties. Specifically, a declaration of unboundedness means that

     // ILOG CPLEX has determined that the model has an unbounded

     // ray. Given any feasible solution x with objective z, a multiple of

     // the unbounded ray can be added to x to give a feasible solution

     // with objective z-1 (or z+1 for maximization models). Thus, if a

     // feasible solution exists, then the optimal objective is

     // unbounded. Note that ILOG CPLEX has not necessarily concluded that

     // a feasible solution exists. Users can call the routine CPXsolninfo

     // to determine whether ILOG CPLEX has also concluded that the model

     // has a feasible solution.

   }  

   MipCplex::Value MipCplex::_getPrimal(int i) const {

     Value x;

     CPXgetmipx(env, lp, &x, i, i);

     return x;

   }

   MipCplex::Value MipCplex::_getPrimalValue() const {

     Value objval;

     CPXgetmipobjval(env, lp, &objval);

     return objval;

   }

 } //END OF NAMESPACE LEMON