/* -*- C++ -*-

 * src/lemon/lp_glpk.cc - Part of LEMON, a generic C++ optimization library

 *

 * Copyright (C) 2005 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.

 *

 */

#ifndef LEMON_LP_GLPK_CC

#define LEMON_LP_GLPK_CC

///\file

///\brief Implementation of the LEMON-GLPK lp solver interface.

#include <lemon/lp_glpk.h>

namespace lemon {

  ///\e

  ///\bug Unimplemented!

  ///

  LpSolverBase &LpGlpk::_newLp()

  {

    LpSolverBase *tmp=0;

    return *tmp;

  }

  ///\e

  ///\bug Unimplemented!

  ///

  LpSolverBase &LpGlpk::_copyLp()

  {

    LpSolverBase *tmp=0;

    return *tmp;

  }

  LpGlpk::LpGlpk() : Parent(), 

		     lp(lpx_create_prob()) {

    ///\todo constrol function for this:

    lpx_set_int_parm(lp, LPX_K_DUAL, 1);

    messageLevel(0);

  }

  LpGlpk::~LpGlpk() {

    lpx_delete_prob(lp);

  }

  int LpGlpk::_addCol() { 

    int i=lpx_add_cols(lp, 1);

    _setColLowerBound(i, -INF);

    _setColUpperBound(i, INF);

    return i;

  }

  int LpGlpk::_addRow() { 

    int i=lpx_add_rows(lp, 1);

    return i;

  }

  void LpGlpk::_eraseCol(int i) {

    int cols[2];

    cols[1]=i;

    lpx_del_cols(lp, 1, cols);

  }

  void LpGlpk::_eraseRow(int i) {

    int rows[2];

    rows[1]=i;

    lpx_del_rows(lp, 1, rows);

  }

  void LpGlpk::_setRowCoeffs(int i, 

			     int length,

			     const int   * indices, 

			     const Value   * values )

  {

    lpx_set_mat_row(lp, i, length,

		    const_cast<int * >(indices) ,

		    const_cast<Value * >(values));

  }

  void LpGlpk::_setColCoeffs(int i, 

			     int length,

			     const int   * indices, 

			     const Value   * values)

  {

    lpx_set_mat_col(lp, i, length,

		    const_cast<int * >(indices),

		    const_cast<Value * >(values));

  }

  void LpGlpk::_setCoeff(int row, int col, Value value) 

  {

    ///FIXME Of course this is not efficient at all, but GLPK knows not more.

    // First approach: get one row, apply changes and set it again

    //(one idea to improve this: maybe it is better to do this with 1 coloumn)

    int mem_length=2+lpx_get_num_cols(lp);

    int* indices = new int[mem_length];

    Value* values = new Value[mem_length];

    int length=lpx_get_mat_row(lp, row, indices, values);

    //The following code does not suppose that the elements of the array indices are sorted

    int i=1;

    bool found=false;

    while (i <= length && !found){

      if (indices[i]==col){

	found = true;

	values[i]=value;

      }

      ++i;

    }

    if (!found){

      ++length;

      indices[length]=col;

      values[length]=value;

    }

    lpx_set_mat_row(lp, row, length, indices, values);

    delete [] indices;

    delete [] values;

  }

  void LpGlpk::_setColLowerBound(int i, Value lo)

  {

    if (lo==INF) {

      //FIXME error

    }

    int b=lpx_get_col_type(lp, i);

    double up=lpx_get_col_ub(lp, i);	

    if (lo==-INF) {

      switch (b) {

      case LPX_FR:

      case LPX_LO:

	lpx_set_col_bnds(lp, i, LPX_FR, lo, up);

	break;

      case LPX_UP:

	break;

      case LPX_DB:

      case LPX_FX:

	lpx_set_col_bnds(lp, i, LPX_UP, lo, up);

	break;

      default: ;

	//FIXME error

      }

    } else {

      switch (b) {

      case LPX_FR:

      case LPX_LO:

	lpx_set_col_bnds(lp, i, LPX_LO, lo, up);

	break;

      case LPX_UP:	  

      case LPX_DB:

      case LPX_FX:

	if (lo==up) 

	  lpx_set_col_bnds(lp, i, LPX_FX, lo, up);

	else 

	  lpx_set_col_bnds(lp, i, LPX_DB, lo, up);

	break;

      default: ;

	//FIXME error

      }

    }

  }

  void LpGlpk::_setColUpperBound(int i, Value up)

  {

    if (up==-INF) {

      //FIXME error

    }

    int b=lpx_get_col_type(lp, i);

    double lo=lpx_get_col_lb(lp, i);

    if (up==INF) {

      switch (b) {

      case LPX_FR:

      case LPX_LO:

	break;

      case LPX_UP:

	lpx_set_col_bnds(lp, i, LPX_FR, lo, up);

	break;

      case LPX_DB:

      case LPX_FX:

	lpx_set_col_bnds(lp, i, LPX_LO, lo, up);

	break;

      default: ;

	//FIXME error

      }

    } else {

      switch (b) {

      case LPX_FR:

	lpx_set_col_bnds(lp, i, LPX_UP, lo, up);

	break;

      case LPX_UP:

	lpx_set_col_bnds(lp, i, LPX_UP, lo, up);

	break;

      case LPX_LO:

      case LPX_DB:

      case LPX_FX:

	if (lo==up) 

	  lpx_set_col_bnds(lp, i, LPX_FX, lo, up);

	else 

	  lpx_set_col_bnds(lp, i, LPX_DB, lo, up);

	break;

      default: ;

	//FIXME error

      }

    }

  }

//   void LpGlpk::_setRowLowerBound(int i, Value lo)

//   {

//     if (lo==INF) {

//       //FIXME error

//     }

//     int b=lpx_get_row_type(lp, i);

//     double up=lpx_get_row_ub(lp, i);	

//     if (lo==-INF) {

//       switch (b) {

//       case LPX_FR:

//       case LPX_LO:

// 	lpx_set_row_bnds(lp, i, LPX_FR, lo, up);

// 	break;

//       case LPX_UP:

// 	break;

//       case LPX_DB:

//       case LPX_FX:

// 	lpx_set_row_bnds(lp, i, LPX_UP, lo, up);

// 	break;

//       default: ;

// 	//FIXME error

//       }

//     } else {

//       switch (b) {

//       case LPX_FR:

//       case LPX_LO:

// 	lpx_set_row_bnds(lp, i, LPX_LO, lo, up);

// 	break;

//       case LPX_UP:	  

//       case LPX_DB:

//       case LPX_FX:

// 	if (lo==up) 

// 	  lpx_set_row_bnds(lp, i, LPX_FX, lo, up);

// 	else 

// 	  lpx_set_row_bnds(lp, i, LPX_DB, lo, up);

// 	break;

//       default: ;

// 	//FIXME error

//       }

//     }

//   }

//   void LpGlpk::_setRowUpperBound(int i, Value up)

//   {

//     if (up==-INF) {

//       //FIXME error

//     }

//     int b=lpx_get_row_type(lp, i);

//     double lo=lpx_get_row_lb(lp, i);

//     if (up==INF) {

//       switch (b) {

//       case LPX_FR:

//       case LPX_LO:

// 	break;

//       case LPX_UP:

// 	lpx_set_row_bnds(lp, i, LPX_FR, lo, up);

// 	break;

//       case LPX_DB:

//       case LPX_FX:

// 	lpx_set_row_bnds(lp, i, LPX_LO, lo, up);

// 	break;

//       default: ;

// 	//FIXME error

//       }

//     } else {

//       switch (b) {

//       case LPX_FR:

// 	lpx_set_row_bnds(lp, i, LPX_UP, lo, up);

// 	break;

//       case LPX_UP:

// 	lpx_set_row_bnds(lp, i, LPX_UP, lo, up);

// 	break;

//       case LPX_LO:

//       case LPX_DB:

//       case LPX_FX:

// 	if (lo==up) 

// 	  lpx_set_row_bnds(lp, i, LPX_FX, lo, up);

// 	else 

// 	  lpx_set_row_bnds(lp, i, LPX_DB, lo, up);

// 	break;

//       default: ;

// 	//FIXME error

//       }

//     }

//   }

  void LpGlpk::_setRowBounds(int i, Value lb, Value ub)

  {

    //Bad parameter

    if (lb==INF || ub==-INF) {

      //FIXME error

    }

    if (lb == -INF){

      if (ub == INF){

	lpx_set_row_bnds(lp, i, LPX_FR, lb, ub);

      }

      else{

	lpx_set_row_bnds(lp, i, LPX_UP, lb, ub);

      }

    }

    else{

      if (ub==INF){

	lpx_set_row_bnds(lp, i, LPX_LO, lb, ub);

      }

      else{

	if (lb == ub){

	  lpx_set_row_bnds(lp, i, LPX_FX, lb, ub);

	}

	else{

	  lpx_set_row_bnds(lp, i, LPX_DB, lb, ub);

	}

      }

    }

  }

  void LpGlpk::_setObjCoeff(int i, Value obj_coef)

  {

    //i=0 means the constant term (shift)

    lpx_set_obj_coef(lp, i, obj_coef);

  }

  void LpGlpk::_clearObj()

  {

    for (int i=0;i<=lpx_get_num_cols(lp);++i){

      lpx_set_obj_coef(lp, i, 0);

    }

  }

//   void LpGlpk::_setObj(int length,

// 		       int  const * indices, 

// 		       Value  const * values )

//   {

//     Value new_values[1+lpx_num_cols()];

//     for (i=0;i<=lpx_num_cols();++i){

//       new_values[i]=0;

//     }

//     for (i=1;i<=length;++i){

//       new_values[indices[i]]=values[i];

//     }

//     for (i=0;i<=lpx_num_cols();++i){

//       lpx_set_obj_coef(lp, i, new_values[i]);

//     }

//   }

  LpGlpk::SolveExitStatus LpGlpk::_solve()

  {

    int i=  lpx_simplex(lp);

    switch (i) {

    case LPX_E_OK: 

      return SOLVED;

      break;

    default:

      return UNSOLVED;

    }

  }

  LpGlpk::Value LpGlpk::_getPrimal(int i)

  {

    return lpx_get_col_prim(lp,i);

  }

  LpGlpk::Value LpGlpk::_getPrimalValue()

  {

    return lpx_get_obj_val(lp);

  }

  LpGlpk::SolutionStatus LpGlpk::_getPrimalStatus()

  {

    int stat=  lpx_get_status(lp);

    switch (stat) {

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

      return UNDEFINED;

      break;

    case LPX_NOFEAS://There is no feasible solution (primal, I guess)

    case LPX_INFEAS://Infeasible 

      return INFEASIBLE;

      break;

    case LPX_UNBND://Unbounded

      return INFINITE;

      break;

    case LPX_FEAS://Feasible

      return FEASIBLE;

      break;

    case LPX_OPT://Feasible

      return OPTIMAL;

      break;

    default:

      return UNDEFINED; //to avoid gcc warning

      //FIXME error

    }

  }

  void LpGlpk::_setMax()

  {

    lpx_set_obj_dir(lp, LPX_MAX);

  }

  void LpGlpk::_setMin()

  {

    lpx_set_obj_dir(lp, LPX_MIN);

  }

  void LpGlpk::messageLevel(int m)

  {

    lpx_set_int_parm(lp, LPX_K_MSGLEV, m);

  }

  void LpGlpk::presolver(bool b)

  {

    lpx_set_int_parm(lp, LPX_K_PRESOL, b);

  }

} //END OF NAMESPACE LEMON

#endif //LEMON_LP_GLPK_CC