1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/deps/glpk/src/glpapi05.c	Sun Nov 06 20:59:10 2011 +0100
     1.3 @@ -0,0 +1,168 @@
     1.4 +/* glpapi05.c (LP basis constructing routines) */
     1.5 +
     1.6 +/***********************************************************************
     1.7 +*  This code is part of GLPK (GNU Linear Programming Kit).
     1.8 +*
     1.9 +*  Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008,
    1.10 +*  2009, 2010, 2011 Andrew Makhorin, Department for Applied Informatics,
    1.11 +*  Moscow Aviation Institute, Moscow, Russia. All rights reserved.
    1.12 +*  E-mail: <mao@gnu.org>.
    1.13 +*
    1.14 +*  GLPK is free software: you can redistribute it and/or modify it
    1.15 +*  under the terms of the GNU General Public License as published by
    1.16 +*  the Free Software Foundation, either version 3 of the License, or
    1.17 +*  (at your option) any later version.
    1.18 +*
    1.19 +*  GLPK is distributed in the hope that it will be useful, but WITHOUT
    1.20 +*  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
    1.21 +*  or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
    1.22 +*  License for more details.
    1.23 +*
    1.24 +*  You should have received a copy of the GNU General Public License
    1.25 +*  along with GLPK. If not, see <http://www.gnu.org/licenses/>.
    1.26 +***********************************************************************/
    1.27 +
    1.28 +#include "glpapi.h"
    1.29 +
    1.30 +/***********************************************************************
    1.31 +*  NAME
    1.32 +*
    1.33 +*  glp_set_row_stat - set (change) row status
    1.34 +*
    1.35 +*  SYNOPSIS
    1.36 +*
    1.37 +*  void glp_set_row_stat(glp_prob *lp, int i, int stat);
    1.38 +*
    1.39 +*  DESCRIPTION
    1.40 +*
    1.41 +*  The routine glp_set_row_stat sets (changes) status of the auxiliary
    1.42 +*  variable associated with i-th row.
    1.43 +*
    1.44 +*  The new status of the auxiliary variable should be specified by the
    1.45 +*  parameter stat as follows:
    1.46 +*
    1.47 +*  GLP_BS - basic variable;
    1.48 +*  GLP_NL - non-basic variable;
    1.49 +*  GLP_NU - non-basic variable on its upper bound; if the variable is
    1.50 +*           not double-bounded, this means the same as GLP_NL (only in
    1.51 +*           case of this routine);
    1.52 +*  GLP_NF - the same as GLP_NL (only in case of this routine);
    1.53 +*  GLP_NS - the same as GLP_NL (only in case of this routine). */
    1.54 +
    1.55 +void glp_set_row_stat(glp_prob *lp, int i, int stat)
    1.56 +{     GLPROW *row;
    1.57 +      if (!(1 <= i && i <= lp->m))
    1.58 +         xerror("glp_set_row_stat: i = %d; row number out of range\n",
    1.59 +            i);
    1.60 +      if (!(stat == GLP_BS || stat == GLP_NL || stat == GLP_NU ||
    1.61 +            stat == GLP_NF || stat == GLP_NS))
    1.62 +         xerror("glp_set_row_stat: i = %d; stat = %d; invalid status\n",
    1.63 +            i, stat);
    1.64 +      row = lp->row[i];
    1.65 +      if (stat != GLP_BS)
    1.66 +      {  switch (row->type)
    1.67 +         {  case GLP_FR: stat = GLP_NF; break;
    1.68 +            case GLP_LO: stat = GLP_NL; break;
    1.69 +            case GLP_UP: stat = GLP_NU; break;
    1.70 +            case GLP_DB: if (stat != GLP_NU) stat = GLP_NL; break;
    1.71 +            case GLP_FX: stat = GLP_NS; break;
    1.72 +            default: xassert(row != row);
    1.73 +         }
    1.74 +      }
    1.75 +      if (row->stat == GLP_BS && stat != GLP_BS ||
    1.76 +          row->stat != GLP_BS && stat == GLP_BS)
    1.77 +      {  /* invalidate the basis factorization */
    1.78 +         lp->valid = 0;
    1.79 +      }
    1.80 +      row->stat = stat;
    1.81 +      return;
    1.82 +}
    1.83 +
    1.84 +/***********************************************************************
    1.85 +*  NAME
    1.86 +*
    1.87 +*  glp_set_col_stat - set (change) column status
    1.88 +*
    1.89 +*  SYNOPSIS
    1.90 +*
    1.91 +*  void glp_set_col_stat(glp_prob *lp, int j, int stat);
    1.92 +*
    1.93 +*  DESCRIPTION
    1.94 +*
    1.95 +*  The routine glp_set_col_stat sets (changes) status of the structural
    1.96 +*  variable associated with j-th column.
    1.97 +*
    1.98 +*  The new status of the structural variable should be specified by the
    1.99 +*  parameter stat as follows:
   1.100 +*
   1.101 +*  GLP_BS - basic variable;
   1.102 +*  GLP_NL - non-basic variable;
   1.103 +*  GLP_NU - non-basic variable on its upper bound; if the variable is
   1.104 +*           not double-bounded, this means the same as GLP_NL (only in
   1.105 +*           case of this routine);
   1.106 +*  GLP_NF - the same as GLP_NL (only in case of this routine);
   1.107 +*  GLP_NS - the same as GLP_NL (only in case of this routine). */
   1.108 +
   1.109 +void glp_set_col_stat(glp_prob *lp, int j, int stat)
   1.110 +{     GLPCOL *col;
   1.111 +      if (!(1 <= j && j <= lp->n))
   1.112 +         xerror("glp_set_col_stat: j = %d; column number out of range\n"
   1.113 +            , j);
   1.114 +      if (!(stat == GLP_BS || stat == GLP_NL || stat == GLP_NU ||
   1.115 +            stat == GLP_NF || stat == GLP_NS))
   1.116 +         xerror("glp_set_col_stat: j = %d; stat = %d; invalid status\n",
   1.117 +            j, stat);
   1.118 +      col = lp->col[j];
   1.119 +      if (stat != GLP_BS)
   1.120 +      {  switch (col->type)
   1.121 +         {  case GLP_FR: stat = GLP_NF; break;
   1.122 +            case GLP_LO: stat = GLP_NL; break;
   1.123 +            case GLP_UP: stat = GLP_NU; break;
   1.124 +            case GLP_DB: if (stat != GLP_NU) stat = GLP_NL; break;
   1.125 +            case GLP_FX: stat = GLP_NS; break;
   1.126 +            default: xassert(col != col);
   1.127 +         }
   1.128 +      }
   1.129 +      if (col->stat == GLP_BS && stat != GLP_BS ||
   1.130 +          col->stat != GLP_BS && stat == GLP_BS)
   1.131 +      {  /* invalidate the basis factorization */
   1.132 +         lp->valid = 0;
   1.133 +      }
   1.134 +      col->stat = stat;
   1.135 +      return;
   1.136 +}
   1.137 +
   1.138 +/***********************************************************************
   1.139 +*  NAME
   1.140 +*
   1.141 +*  glp_std_basis - construct standard initial LP basis
   1.142 +*
   1.143 +*  SYNOPSIS
   1.144 +*
   1.145 +*  void glp_std_basis(glp_prob *lp);
   1.146 +*
   1.147 +*  DESCRIPTION
   1.148 +*
   1.149 +*  The routine glp_std_basis builds the "standard" (trivial) initial
   1.150 +*  basis for the specified problem object.
   1.151 +*
   1.152 +*  In the "standard" basis all auxiliary variables are basic, and all
   1.153 +*  structural variables are non-basic. */
   1.154 +
   1.155 +void glp_std_basis(glp_prob *lp)
   1.156 +{     int i, j;
   1.157 +      /* make all auxiliary variables basic */
   1.158 +      for (i = 1; i <= lp->m; i++)
   1.159 +         glp_set_row_stat(lp, i, GLP_BS);
   1.160 +      /* make all structural variables non-basic */
   1.161 +      for (j = 1; j <= lp->n; j++)
   1.162 +      {  GLPCOL *col = lp->col[j];
   1.163 +         if (col->type == GLP_DB && fabs(col->lb) > fabs(col->ub))
   1.164 +            glp_set_col_stat(lp, j, GLP_NU);
   1.165 +         else
   1.166 +            glp_set_col_stat(lp, j, GLP_NL);
   1.167 +      }
   1.168 +      return;
   1.169 +}
   1.170 +
   1.171 +/* eof */