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89 lines
2.6 KiB
89 lines
2.6 KiB
/* bfx.c (LP basis factorization driver, rational arithmetic) */
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/***********************************************************************
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* This code is part of GLPK (GNU Linear Programming Kit).
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*
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* Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008,
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* 2009, 2010, 2011, 2013 Andrew Makhorin, Department for Applied
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* Informatics, Moscow Aviation Institute, Moscow, Russia. All rights
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* reserved. E-mail: <mao@gnu.org>.
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*
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* GLPK is free software: you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* GLPK is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
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* License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GLPK. If not, see <http://www.gnu.org/licenses/>.
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***********************************************************************/
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#include "bfx.h"
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#include "env.h"
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#include "lux.h"
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struct BFX
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{ int valid;
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LUX *lux;
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};
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BFX *bfx_create_binv(void)
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{ /* create factorization of the basis matrix */
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BFX *bfx;
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bfx = xmalloc(sizeof(BFX));
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bfx->valid = 0;
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bfx->lux = NULL;
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return bfx;
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}
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int bfx_factorize(BFX *binv, int m, int (*col)(void *info, int j,
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int ind[], mpq_t val[]), void *info)
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{ /* compute factorization of the basis matrix */
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int ret;
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xassert(m > 0);
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if (binv->lux != NULL && binv->lux->n != m)
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{ lux_delete(binv->lux);
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binv->lux = NULL;
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}
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if (binv->lux == NULL)
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binv->lux = lux_create(m);
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ret = lux_decomp(binv->lux, col, info);
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binv->valid = (ret == 0);
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return ret;
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}
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void bfx_ftran(BFX *binv, mpq_t x[], int save)
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{ /* perform forward transformation (FTRAN) */
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xassert(binv->valid);
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lux_solve(binv->lux, 0, x);
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xassert(save == save);
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return;
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}
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void bfx_btran(BFX *binv, mpq_t x[])
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{ /* perform backward transformation (BTRAN) */
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xassert(binv->valid);
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lux_solve(binv->lux, 1, x);
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return;
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}
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int bfx_update(BFX *binv, int j)
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{ /* update factorization of the basis matrix */
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xassert(binv->valid);
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xassert(1 <= j && j <= binv->lux->n);
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return 1;
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}
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void bfx_delete_binv(BFX *binv)
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{ /* delete factorization of the basis matrix */
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if (binv->lux != NULL)
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lux_delete(binv->lux);
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xfree(binv);
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return;
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}
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/* eof */
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