/* -*- 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