alpar@1: /* glpapi04.c (problem scaling routines) */
alpar@1: 
alpar@1: /***********************************************************************
alpar@1: *  This code is part of GLPK (GNU Linear Programming Kit).
alpar@1: *
alpar@1: *  Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008,
alpar@1: *  2009, 2010 Andrew Makhorin, Department for Applied Informatics,
alpar@1: *  Moscow Aviation Institute, Moscow, Russia. All rights reserved.
alpar@1: *  E-mail: <mao@gnu.org>.
alpar@1: *
alpar@1: *  GLPK is free software: you can redistribute it and/or modify it
alpar@1: *  under the terms of the GNU General Public License as published by
alpar@1: *  the Free Software Foundation, either version 3 of the License, or
alpar@1: *  (at your option) any later version.
alpar@1: *
alpar@1: *  GLPK is distributed in the hope that it will be useful, but WITHOUT
alpar@1: *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
alpar@1: *  or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
alpar@1: *  License for more details.
alpar@1: *
alpar@1: *  You should have received a copy of the GNU General Public License
alpar@1: *  along with GLPK. If not, see <http://www.gnu.org/licenses/>.
alpar@1: ***********************************************************************/
alpar@1: 
alpar@1: #include "glpapi.h"
alpar@1: 
alpar@1: /***********************************************************************
alpar@1: *  NAME
alpar@1: *
alpar@1: *  glp_set_rii - set (change) row scale factor
alpar@1: *
alpar@1: *  SYNOPSIS
alpar@1: *
alpar@1: *  void glp_set_rii(glp_prob *lp, int i, double rii);
alpar@1: *
alpar@1: *  DESCRIPTION
alpar@1: *
alpar@1: *  The routine glp_set_rii sets (changes) the scale factor r[i,i] for
alpar@1: *  i-th row of the specified problem object. */
alpar@1: 
alpar@1: void glp_set_rii(glp_prob *lp, int i, double rii)
alpar@1: {     if (!(1 <= i && i <= lp->m))
alpar@1:          xerror("glp_set_rii: i = %d; row number out of range\n", i);
alpar@1:       if (rii <= 0.0)
alpar@1:          xerror("glp_set_rii: i = %d; rii = %g; invalid scale factor\n",
alpar@1:             i, rii);
alpar@1:       if (lp->valid && lp->row[i]->rii != rii)
alpar@1:       {  GLPAIJ *aij;
alpar@1:          for (aij = lp->row[i]->ptr; aij != NULL; aij = aij->r_next)
alpar@1:          {  if (aij->col->stat == GLP_BS)
alpar@1:             {  /* invalidate the basis factorization */
alpar@1:                lp->valid = 0;
alpar@1:                break;
alpar@1:             }
alpar@1:          }
alpar@1:       }
alpar@1:       lp->row[i]->rii = rii;
alpar@1:       return;
alpar@1: }
alpar@1: 
alpar@1: /***********************************************************************
alpar@1: *  NAME
alpar@1: *
alpar@1: *  glp_set sjj - set (change) column scale factor
alpar@1: *
alpar@1: *  SYNOPSIS
alpar@1: *
alpar@1: *  void glp_set_sjj(glp_prob *lp, int j, double sjj);
alpar@1: *
alpar@1: *  DESCRIPTION
alpar@1: *
alpar@1: *  The routine glp_set_sjj sets (changes) the scale factor s[j,j] for
alpar@1: *  j-th column of the specified problem object. */
alpar@1: 
alpar@1: void glp_set_sjj(glp_prob *lp, int j, double sjj)
alpar@1: {     if (!(1 <= j && j <= lp->n))
alpar@1:          xerror("glp_set_sjj: j = %d; column number out of range\n", j);
alpar@1:       if (sjj <= 0.0)
alpar@1:          xerror("glp_set_sjj: j = %d; sjj = %g; invalid scale factor\n",
alpar@1:             j, sjj);
alpar@1:       if (lp->valid && lp->col[j]->sjj != sjj && lp->col[j]->stat ==
alpar@1:          GLP_BS)
alpar@1:       {  /* invalidate the basis factorization */
alpar@1:          lp->valid = 0;
alpar@1:       }
alpar@1:       lp->col[j]->sjj = sjj;
alpar@1:       return;
alpar@1: }
alpar@1: 
alpar@1: /***********************************************************************
alpar@1: *  NAME
alpar@1: *
alpar@1: *  glp_get_rii - retrieve row scale factor
alpar@1: *
alpar@1: *  SYNOPSIS
alpar@1: *
alpar@1: *  double glp_get_rii(glp_prob *lp, int i);
alpar@1: *
alpar@1: *  RETURNS
alpar@1: *
alpar@1: *  The routine glp_get_rii returns current scale factor r[i,i] for i-th
alpar@1: *  row of the specified problem object. */
alpar@1: 
alpar@1: double glp_get_rii(glp_prob *lp, int i)
alpar@1: {     if (!(1 <= i && i <= lp->m))
alpar@1:          xerror("glp_get_rii: i = %d; row number out of range\n", i);
alpar@1:       return lp->row[i]->rii;
alpar@1: }
alpar@1: 
alpar@1: /***********************************************************************
alpar@1: *  NAME
alpar@1: *
alpar@1: *  glp_get_sjj - retrieve column scale factor
alpar@1: *
alpar@1: *  SYNOPSIS
alpar@1: *
alpar@1: *  double glp_get_sjj(glp_prob *lp, int j);
alpar@1: *
alpar@1: *  RETURNS
alpar@1: *
alpar@1: *  The routine glp_get_sjj returns current scale factor s[j,j] for j-th
alpar@1: *  column of the specified problem object. */
alpar@1: 
alpar@1: double glp_get_sjj(glp_prob *lp, int j)
alpar@1: {     if (!(1 <= j && j <= lp->n))
alpar@1:          xerror("glp_get_sjj: j = %d; column number out of range\n", j);
alpar@1:       return lp->col[j]->sjj;
alpar@1: }
alpar@1: 
alpar@1: /***********************************************************************
alpar@1: *  NAME
alpar@1: *
alpar@1: *  glp_unscale_prob - unscale problem data
alpar@1: *
alpar@1: *  SYNOPSIS
alpar@1: *
alpar@1: *  void glp_unscale_prob(glp_prob *lp);
alpar@1: *
alpar@1: *  DESCRIPTION
alpar@1: *
alpar@1: *  The routine glp_unscale_prob performs unscaling of problem data for
alpar@1: *  the specified problem object.
alpar@1: *
alpar@1: *  "Unscaling" means replacing the current scaling matrices R and S by
alpar@1: *  unity matrices that cancels the scaling effect. */
alpar@1: 
alpar@1: void glp_unscale_prob(glp_prob *lp)
alpar@1: {     int m = glp_get_num_rows(lp);
alpar@1:       int n = glp_get_num_cols(lp);
alpar@1:       int i, j;
alpar@1:       for (i = 1; i <= m; i++) glp_set_rii(lp, i, 1.0);
alpar@1:       for (j = 1; j <= n; j++) glp_set_sjj(lp, j, 1.0);
alpar@1:       return;
alpar@1: }
alpar@1: 
alpar@1: /* eof */