COIN-OR::LEMON - Graph Library

source: glpk-cmake/src/glpbfx.c @ 1:c445c931472f

Last change on this file since 1:c445c931472f was 1:c445c931472f, checked in by Alpar Juttner <alpar@…>, 10 years ago

Import glpk-4.45

  • Generated files and doc/notes are removed
File size: 2.6 KB
Line 
1/* glpbfx.c */
2
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***********************************************************************/
24
25typedef struct BFX BFX;
26#define GLPBFX_DEFINED
27#include "glpbfx.h"
28#include "glpenv.h"
29#include "glplux.h"
30
31struct BFX
32{     int valid;
33      LUX *lux;
34};
35
36BFX *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}
44
45int 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}
60
61void 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}
68
69void 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}
75
76int 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}
82
83void 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}
90
91/* eof */
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