source: lemon-0.x/src/lemon/lp_glpk.cc @ 1431:ad44b1dd8013

/* -*- 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::_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