/* glpapi04.c (problem scaling routines) */

 /***********************************************************************

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

 *

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

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

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

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

 *

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

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

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

 *  (at your option) any later version.

 *

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

 *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY

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

 *  License for more details.

 *

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

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

 ***********************************************************************/

 #include "glpapi.h"

 /***********************************************************************

 *  NAME

 *

 *  glp_set_rii - set (change) row scale factor

 *

 *  SYNOPSIS

 *

 *  void glp_set_rii(glp_prob *lp, int i, double rii);

 *

 *  DESCRIPTION

 *

 *  The routine glp_set_rii sets (changes) the scale factor r[i,i] for

 *  i-th row of the specified problem object. */

 void glp_set_rii(glp_prob *lp, int i, double rii)

 {     if (!(1 <= i && i <= lp->m))

          xerror("glp_set_rii: i = %d; row number out of range\n", i);

       if (rii <= 0.0)

          xerror("glp_set_rii: i = %d; rii = %g; invalid scale factor\n",

             i, rii);

       if (lp->valid && lp->row[i]->rii != rii)

       {  GLPAIJ *aij;

          for (aij = lp->row[i]->ptr; aij != NULL; aij = aij->r_next)

          {  if (aij->col->stat == GLP_BS)

             {  /* invalidate the basis factorization */

                lp->valid = 0;

                break;

             }

          }

       }

       lp->row[i]->rii = rii;

       return;

 }

 /***********************************************************************

 *  NAME

 *

 *  glp_set sjj - set (change) column scale factor

 *

 *  SYNOPSIS

 *

 *  void glp_set_sjj(glp_prob *lp, int j, double sjj);

 *

 *  DESCRIPTION

 *

 *  The routine glp_set_sjj sets (changes) the scale factor s[j,j] for

 *  j-th column of the specified problem object. */

 void glp_set_sjj(glp_prob *lp, int j, double sjj)

 {     if (!(1 <= j && j <= lp->n))

          xerror("glp_set_sjj: j = %d; column number out of range\n", j);

       if (sjj <= 0.0)

          xerror("glp_set_sjj: j = %d; sjj = %g; invalid scale factor\n",

             j, sjj);

       if (lp->valid && lp->col[j]->sjj != sjj && lp->col[j]->stat ==

          GLP_BS)

       {  /* invalidate the basis factorization */

          lp->valid = 0;

       }

       lp->col[j]->sjj = sjj;

       return;

 }

 /***********************************************************************

 *  NAME

 *

 *  glp_get_rii - retrieve row scale factor

 *

 *  SYNOPSIS

 *

 *  double glp_get_rii(glp_prob *lp, int i);

 *

 *  RETURNS

 *

 *  The routine glp_get_rii returns current scale factor r[i,i] for i-th

 *  row of the specified problem object. */

 double glp_get_rii(glp_prob *lp, int i)

 {     if (!(1 <= i && i <= lp->m))

          xerror("glp_get_rii: i = %d; row number out of range\n", i);

       return lp->row[i]->rii;

 }

 /***********************************************************************

 *  NAME

 *

 *  glp_get_sjj - retrieve column scale factor

 *

 *  SYNOPSIS

 *

 *  double glp_get_sjj(glp_prob *lp, int j);

 *

 *  RETURNS

 *

 *  The routine glp_get_sjj returns current scale factor s[j,j] for j-th

 *  column of the specified problem object. */

 double glp_get_sjj(glp_prob *lp, int j)

 {     if (!(1 <= j && j <= lp->n))

          xerror("glp_get_sjj: j = %d; column number out of range\n", j);

       return lp->col[j]->sjj;

 }

 /***********************************************************************

 *  NAME

 *

 *  glp_unscale_prob - unscale problem data

 *

 *  SYNOPSIS

 *

 *  void glp_unscale_prob(glp_prob *lp);

 *

 *  DESCRIPTION

 *

 *  The routine glp_unscale_prob performs unscaling of problem data for

 *  the specified problem object.

 *

 *  "Unscaling" means replacing the current scaling matrices R and S by

 *  unity matrices that cancels the scaling effect. */

 void glp_unscale_prob(glp_prob *lp)

 {     int m = glp_get_num_rows(lp);

       int n = glp_get_num_cols(lp);

       int i, j;

       for (i = 1; i <= m; i++) glp_set_rii(lp, i, 1.0);

       for (j = 1; j <= n; j++) glp_set_sjj(lp, j, 1.0);

       return;

 }

 /* eof */