plreal.c

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/*
 
  $Id: plreal.c 1641 2016-03-02 08:20:19Z coelho $
 
  Copyright 1989-2016 MINES ParisTech
 
  This file is part of Linear/C3 Library.
 
  Linear/C3 Library is free software: you can redistribute it and/or modify it
  under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  any later version.
 
  Linear/C3 Library is distributed in the hope that it will be useful, but WITHOUT ANY
  WARRANTY; without even the implied warranty of MERCHANTABILITY or
  FITNESS FOR A PARTICULAR PURPOSE.
 
  See the GNU Lesser General Public License for more details.
 
  You should have received a copy of the GNU Lesser General Public License
  along with Linear/C3 Library.  If not, see <http://www.gnu.org/licenses/>.
 
*/
 
 /* package plint */
 
#ifdef HAVE_CONFIG_H
    #include "config.h"
#endif
 
#include <stdio.h>
#include "boolean.h"
#include "arithmetique.h"
#include "vecteur.h"
#include "contrainte.h"
#include "sc.h"
 
#include "sommet.h"
 
/* pour recuperer les declarations des fonctions de conversion de
 * sc en liste de sommets et reciproquement, bien que ca casse le
 * DAG des types de donnees
 */
#include "ray_dte.h"
#include "polyedre.h"
#include "matrix.h"
 
#include "plint.h"
 
/* Psysteme plreal(Psysteme first_sys, Psommet fonct):
 * Resolution d'un systeme lineaire en nombres reels positifs
 *
 *
 *  resultat retourne par la fonction :
 *
 *  Psysteme       : systeme lineaire 
 *
 *  Les parametres de la fonction :
 *
 *  Psysteme first_syst  : systeme lineaire initial
 *  Psommet fonct       : fonction economique du  programme lineaire
 */
Psysteme plreal(first_sys,fonct)
Psysteme first_sys;
Psommet fonct;
{
    Psommet sys1 = NULL;
    Psysteme syst_res = NULL;
    Pvecteur lvbase = NULL;
    int nb_som = 0;
    int nbvars;
    Pbase b =BASE_NULLE;
 
    if (first_sys) {
        nbvars = first_sys->dimension;
        b = base_dup(first_sys->base);
 
        if ((first_sys->egalites != NULL) 
            || (first_sys->inegalites != NULL)) {
            /* conversion du systeme lineaire en sommet    */
            sys1 = sys_som_conv(first_sys,&nb_som);
            /* ajout des variables d'ecart   */
            if ((sys1 = eq_in_ineq(&sys1,&nb_som,&lvbase)) != NULL) {
                sys1 = var_ecart_sup(sys1,nb_som,&lvbase,&nbvars,&b);
                sys1 = primal_pivot(sys1,&lvbase,nb_som,fonct);
            }
 
            /* calcul de la solution reelle positive  */
            while ((sys1 != NULL) && 
                   (dual_pivot_pas(&sys1,&lvbase,nb_som,fonct,&nbvars,&b) == true));
 
            /* si le systeme est non faisable,
               liberation de l'espace memoire ocupe par la fonction 
               economique  */
            if (sys1 == NULL && fonct != NULL) {
                vect_rm(fonct->vecteur);
                fonct->vecteur = NULL;
            }
            /* conversion du sommet en systeme lineaire  */
            syst_res = som_sys_conv(sys1);
            /* si le systeme est non faisable,
               liberation de l'espace memoire occupe par les variables */
            if (syst_res != NULL) {
                syst_res->base = b;
                syst_res->dimension = nbvars;
            }
        }
    } 
    sommets_rm(sys1);
    vect_rm(lvbase);
 
    return(syst_res);
}