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/* wrmaxf.c (write maximum flow problem data in DIMACS format) */
/***********************************************************************
* This code is part of GLPK (GNU Linear Programming Kit).
* Copyright (C) 2009-2016 Free Software Foundation, Inc.
* Written by Andrew Makhorin <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 "env.h"
#include "glpk.h"
#define xfprintf glp_format
/***********************************************************************
* NAME
*
* glp_write_maxflow - write maximum flow problem data in DIMACS format
*
* SYNOPSIS
*
* int glp_write_maxflow(glp_graph *G, int s, int t, int a_cap,
* const char *fname);
*
* DESCRIPTION
*
* The routine glp_write_maxflow writes maximum flow problem data in
* DIMACS format to a text file.
*
* RETURNS
*
* If the operation was successful, the routine returns zero. Otherwise
* it prints an error message and returns non-zero. */
int glp_write_maxflow(glp_graph *G, int s, int t, int a_cap,
const char *fname)
{ glp_file *fp;
glp_vertex *v;
glp_arc *a;
int i, count = 0, ret;
double cap;
if (!(1 <= s && s <= G->nv))
xerror("glp_write_maxflow: s = %d; source node number out of r"
"ange\n", s);
if (!(1 <= t && t <= G->nv))
xerror("glp_write_maxflow: t = %d: sink node number out of ran"
"ge\n", t);
if (a_cap >= 0 && a_cap > G->a_size - (int)sizeof(double))
xerror("glp_write_mincost: a_cap = %d; invalid offset\n",
a_cap);
xprintf("Writing maximum flow problem data to '%s'...\n",
fname);
fp = glp_open(fname, "w");
if (fp == NULL)
{ xprintf("Unable to create '%s' - %s\n", fname, get_err_msg());
ret = 1;
goto done;
}
xfprintf(fp, "c %s\n",
G->name == NULL ? "unknown" : G->name), count++;
xfprintf(fp, "p max %d %d\n", G->nv, G->na), count++;
xfprintf(fp, "n %d s\n", s), count++;
xfprintf(fp, "n %d t\n", t), count++;
for (i = 1; i <= G->nv; i++)
{ v = G->v[i];
for (a = v->out; a != NULL; a = a->t_next)
{ if (a_cap >= 0)
memcpy(&cap, (char *)a->data + a_cap, sizeof(double));
else
cap = 1.0;
xfprintf(fp, "a %d %d %.*g\n",
a->tail->i, a->head->i, DBL_DIG, cap), count++;
}
}
xfprintf(fp, "c eof\n"), count++;
#if 0 /* FIXME */
xfflush(fp);
#endif
if (glp_ioerr(fp))
{ xprintf("Write error on '%s' - %s\n", fname, get_err_msg());
ret = 1;
goto done;
}
xprintf("%d lines were written\n", count);
ret = 0;
done: if (fp != NULL) glp_close(fp);
return ret;
}
/* eof */
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