glpk-cmake: src/glpbfx.c@4c8956a7bdf4

     1 /* glpbfx.c */

     3 /***********************************************************************

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

5 *

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

     7 *  2009, 2010 Andrew Makhorin, Department for Applied Informatics,

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

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

    10 *

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

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

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

    14 *  (at your option) any later version.

    15 *

    16 *  GLPK is distributed in the hope that it will be useful, but WITHOUT

    17 *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY

    18 *  or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public

    19 *  License for more details.

    20 *

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

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

    23 ***********************************************************************/

    25 typedef struct BFX BFX;

    26 #define GLPBFX_DEFINED

    27 #include "glpbfx.h"

    28 #include "glpenv.h"

    29 #include "glplux.h"

    31 struct BFX

    32 {     int valid;

    33       LUX *lux;

    34 };

    36 BFX *bfx_create_binv(void)

    37 {     /* create factorization of the basis matrix */

    38       BFX *bfx;

    39       bfx = xmalloc(sizeof(BFX));

    40       bfx->valid = 0;

    41       bfx->lux = NULL;

    42       return bfx;

    43 }

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

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

    47 {     /* compute factorization of the basis matrix */

    48       int ret;

    49       xassert(m > 0);

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

    51       {  lux_delete(binv->lux);

    52          binv->lux = NULL;

    53       }

    54       if (binv->lux == NULL)

    55          binv->lux = lux_create(m);

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

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

    58       return ret;

    59 }

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

    62 {     /* perform forward transformation (FTRAN) */

    63       xassert(binv->valid);

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

    65       xassert(save == save);

    66       return;

    67 }

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

    70 {     /* perform backward transformation (BTRAN) */

    71       xassert(binv->valid);

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

    73       return;

    74 }

    76 int bfx_update(BFX *binv, int j)

    77 {     /* update factorization of the basis matrix */

    78       xassert(binv->valid);

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

    80       return 1;

    81 }

    83 void bfx_delete_binv(BFX *binv)

    84 {     /* delete factorization of the basis matrix */

    85       if (binv->lux != NULL)

    86          lux_delete(binv->lux);

    87       xfree(binv);

    88       return;

    89 }

    91 /* eof */

author	Alpar Juttner <alpar@cs.elte.hu>
	Sun, 05 Dec 2010 17:35:23 +0100
changeset 2	4c8956a7bdf4
permissions	-rw-r--r--