/* glpbfx.c */

/***********************************************************************

*  This code is part of GLPK (GNU Linear Programming Kit).

*

*  Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008,

*  2009, 2010 Andrew Makhorin, Department for Applied Informatics,

*  Moscow Aviation Institute, Moscow, Russia. All rights reserved.

*  E-mail: <mao@gnu.org>.

*

*  GLPK is free software: you can redistribute it and/or modify it

*  under the terms of the GNU General Public License as published by

*  the Free Software Foundation, either version 3 of the License, or

*  (at your option) any later version.

*

*  GLPK 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 General Public

*  License for more details.

*

*  You should have received a copy of the GNU General Public License

*  along with GLPK. If not, see <http://www.gnu.org/licenses/>.

***********************************************************************/

typedef struct BFX BFX;

#define GLPBFX_DEFINED

#include "glpbfx.h"

#include "glpenv.h"

#include "glplux.h"

struct BFX

{     int valid;

      LUX *lux;

};

BFX *bfx_create_binv(void)

{     /* create factorization of the basis matrix */

      BFX *bfx;

      bfx = xmalloc(sizeof(BFX));

      bfx->valid = 0;

      bfx->lux = NULL;

      return bfx;

}

int bfx_factorize(BFX *binv, int m, int (*col)(void *info, int j,

      int ind[], mpq_t val[]), void *info)

{     /* compute factorization of the basis matrix */

      int ret;

      xassert(m > 0);

      if (binv->lux != NULL && binv->lux->n != m)

      {  lux_delete(binv->lux);

         binv->lux = NULL;

      }

      if (binv->lux == NULL)

         binv->lux = lux_create(m);

      ret = lux_decomp(binv->lux, col, info);

      binv->valid = (ret == 0);

      return ret;

}

void bfx_ftran(BFX *binv, mpq_t x[], int save)

{     /* perform forward transformation (FTRAN) */

      xassert(binv->valid);

      lux_solve(binv->lux, 0, x);

      xassert(save == save);

      return;

}

void bfx_btran(BFX *binv, mpq_t x[])

{     /* perform backward transformation (BTRAN) */

      xassert(binv->valid);

      lux_solve(binv->lux, 1, x);

      return;

}

int bfx_update(BFX *binv, int j)

{     /* update factorization of the basis matrix */

      xassert(binv->valid);

      xassert(1 <= j && j <= binv->lux->n);

      return 1;

}

void bfx_delete_binv(BFX *binv)

{     /* delete factorization of the basis matrix */

      if (binv->lux != NULL)

         lux_delete(binv->lux);

      xfree(binv);

      return;

}

/* eof */