/* -*- mode: C++; indent-tabs-mode: nil; -*-

  *

  * 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-GLPK mip solver interface.

 #include <lemon/mip_glpk.h>

 extern "C" {

 #include <glpk.h>

 }

 #if GLP_MAJOR_VERSION > 4 || (GLP_MAJOR_VERSION == 4 && GLP_MINOR_VERSION > 15)

 #define LEMON_glp(func) (glp_##func)

 #define LEMON_lpx(func) (lpx_##func)

 #define LEMON_GLP(def) (GLP_##def)

 #define LEMON_LPX(def) (LPX_##def)

 #else

 #define LEMON_glp(func) (lpx_##func)

 #define LEMON_lpx(func) (lpx_##func)

 #define LEMON_GLP(def) (LPX_##def)

 #define LEMON_LPX(def) (LPX_##def)

 #endif

 namespace lemon {

   MipGlpk::MipGlpk() {

 #if !(GLP_MAJOR_VERSION > 4 || \

       (GLP_MAJOR_VERSION == 4 && GLP_MINOR_VERSION > 15))

     LEMON_lpx(set_class)(lp,LEMON_GLP(MIP));

 #endif

   }

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

     switch (col_type){

       case INT:

         LEMON_glp(set_col_kind)(lp,i,LEMON_GLP(IV));

         break;

       case REAL:

         LEMON_glp(set_col_kind)(lp,i,LEMON_GLP(CV));

         break;

     default:;

         //FIXME problem

     }

   }

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

     switch (LEMON_glp(get_col_kind)(lp,i)){

     case LEMON_GLP(IV):

       return INT;//Or binary

     case LEMON_GLP(CV):

       return REAL;

     default:

       return REAL;//Error!

     }

   }

   LpGlpk::SolveExitStatus MipGlpk::_solve() {

     int result = LEMON_lpx(simplex)(lp);

     // hack: mip does not contain integer variable

 #if GLP_MAJOR_VERSION == 4 && GLP_MINOR_VERSION == 16

     int tmp = -1;

     if (LEMON_glp(get_num_int(lp)) == 0) {

       tmp = LEMON_lpx(add_cols)(lp, 1);

       LEMON_glp(set_col_bnds)(lp, tmp, LEMON_GLP(FX), 0.0, 0.0);

       LEMON_glp(set_col_kind)(lp, tmp, LEMON_GLP(IV));

     }

 #endif

     if (LEMON_lpx(get_status)(lp)==LEMON_LPX(OPT)) {

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

       //version of lpx_integer

       result = LEMON_lpx(integer)(lp);

       switch (result){

       case LEMON_LPX(E_OK):

         solved = true;

         break;

       default:

         solved = false;

       }

     } else {

       solved = false;

     }

 #if GLP_MAJOR_VERSION == 4 && GLP_MINOR_VERSION == 16

     if (tmp != -1) {

       int tmpa[2];

       tmpa[1] = tmp;

       LEMON_lpx(del_cols)(lp, 1, tmpa);

     }

 #endif

     return solved ? SOLVED : UNSOLVED;

   }

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

     if (LEMON_lpx(get_status)(lp)==LEMON_LPX(OPT)){

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

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

       int stat= LEMON_lpx(mip_status)(lp);

       switch (stat) {

       case LEMON_LPX(I_UNDEF)://Undefined (no solve has been run yet)

         return UNDEFINED;

       case LEMON_LPX(I_NOFEAS)://There is no feasible integral solution

         return INFEASIBLE;

         //     case LEMON_LPX(UNBND)://Unbounded

         //       return INFINITE;

       case LEMON_LPX(I_FEAS)://Feasible

         return FEASIBLE;

       case LEMON_LPX(I_OPT)://Feasible

         return OPTIMAL;

       default:

         return UNDEFINED; //to avoid gcc warning

       //FIXME error

       }

     }

     else

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

                         //relaxation look like

   }

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

     return LEMON_glp(mip_col_val)(lp,i);

   }

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

     return LEMON_glp(mip_obj_val)(lp);

   }

 } //END OF NAMESPACE LEMON