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157 lines
4.5 KiB
157 lines
4.5 KiB
/* glpapi04.c (problem scaling routines) */
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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 "env.h"
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#include "prob.h"
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/***********************************************************************
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* NAME
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*
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* glp_set_rii - set (change) row scale factor
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*
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* SYNOPSIS
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*
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* void glp_set_rii(glp_prob *lp, int i, double rii);
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*
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* DESCRIPTION
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*
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* The routine glp_set_rii sets (changes) the scale factor r[i,i] for
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* i-th row of the specified problem object. */
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void glp_set_rii(glp_prob *lp, int i, double rii)
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{ if (!(1 <= i && i <= lp->m))
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xerror("glp_set_rii: i = %d; row number out of range\n", i);
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if (rii <= 0.0)
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xerror("glp_set_rii: i = %d; rii = %g; invalid scale factor\n",
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i, rii);
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if (lp->valid && lp->row[i]->rii != rii)
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{ GLPAIJ *aij;
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for (aij = lp->row[i]->ptr; aij != NULL; aij = aij->r_next)
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{ if (aij->col->stat == GLP_BS)
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{ /* invalidate the basis factorization */
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lp->valid = 0;
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break;
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}
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}
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}
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lp->row[i]->rii = rii;
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return;
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}
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/***********************************************************************
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* NAME
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*
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* glp_set sjj - set (change) column scale factor
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*
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* SYNOPSIS
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*
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* void glp_set_sjj(glp_prob *lp, int j, double sjj);
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*
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* DESCRIPTION
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*
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* The routine glp_set_sjj sets (changes) the scale factor s[j,j] for
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* j-th column of the specified problem object. */
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void glp_set_sjj(glp_prob *lp, int j, double sjj)
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{ if (!(1 <= j && j <= lp->n))
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xerror("glp_set_sjj: j = %d; column number out of range\n", j);
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if (sjj <= 0.0)
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xerror("glp_set_sjj: j = %d; sjj = %g; invalid scale factor\n",
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j, sjj);
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if (lp->valid && lp->col[j]->sjj != sjj && lp->col[j]->stat ==
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GLP_BS)
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{ /* invalidate the basis factorization */
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lp->valid = 0;
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}
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lp->col[j]->sjj = sjj;
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return;
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}
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/***********************************************************************
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* NAME
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*
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* glp_get_rii - retrieve row scale factor
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*
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* SYNOPSIS
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*
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* double glp_get_rii(glp_prob *lp, int i);
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*
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* RETURNS
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*
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* The routine glp_get_rii returns current scale factor r[i,i] for i-th
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* row of the specified problem object. */
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double glp_get_rii(glp_prob *lp, int i)
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{ if (!(1 <= i && i <= lp->m))
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xerror("glp_get_rii: i = %d; row number out of range\n", i);
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return lp->row[i]->rii;
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}
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/***********************************************************************
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* NAME
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*
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* glp_get_sjj - retrieve column scale factor
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*
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* SYNOPSIS
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*
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* double glp_get_sjj(glp_prob *lp, int j);
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*
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* RETURNS
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*
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* The routine glp_get_sjj returns current scale factor s[j,j] for j-th
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* column of the specified problem object. */
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double glp_get_sjj(glp_prob *lp, int j)
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{ if (!(1 <= j && j <= lp->n))
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xerror("glp_get_sjj: j = %d; column number out of range\n", j);
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return lp->col[j]->sjj;
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}
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/***********************************************************************
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* NAME
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*
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* glp_unscale_prob - unscale problem data
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*
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* SYNOPSIS
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*
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* void glp_unscale_prob(glp_prob *lp);
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*
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* DESCRIPTION
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*
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* The routine glp_unscale_prob performs unscaling of problem data for
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* the specified problem object.
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*
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* "Unscaling" means replacing the current scaling matrices R and S by
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* unity matrices that cancels the scaling effect. */
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void glp_unscale_prob(glp_prob *lp)
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{ int m = glp_get_num_rows(lp);
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int n = glp_get_num_cols(lp);
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int i, j;
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for (i = 1; i <= m; i++) glp_set_rii(lp, i, 1.0);
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for (j = 1; j <= n; j++) glp_set_sjj(lp, j, 1.0);
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return;
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}
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/* eof */
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