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/* rng/default.c
*
* Copyright (C) 1996, 1997, 1998, 1999, 2000 James Theiler, Brian Gough
*
* This program 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 2 of the License, or (at
* your option) any later version.
*
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include <config.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <gsl/gsl_rng.h>
#include <gsl/gsl_errno.h>
/* The initial defaults are defined in the file mt.c, so we can get
access to the static parts of the default generator. */
const gsl_rng_type *
gsl_rng_env_setup (void)
{
unsigned long int seed = 0;
const char *p = getenv ("GSL_RNG_TYPE");
if (p)
{
const gsl_rng_type **t, **t0 = gsl_rng_types_setup ();
gsl_rng_default = 0;
/* check GSL_RNG_TYPE against the names of all the generators */
for (t = t0; *t != 0; t++)
{
if (strcmp (p, (*t)->name) == 0)
{
gsl_rng_default = *t;
break;
}
}
if (gsl_rng_default == 0)
{
int i = 0;
fprintf (stderr, "GSL_RNG_TYPE=%s not recognized\n", p);
fprintf (stderr, "Valid generator types are:\n");
for (t = t0; *t != 0; t++)
{
fprintf (stderr, " %18s", (*t)->name);
if ((++i) % 4 == 0)
{
fputc ('\n', stderr);
}
}
fputc ('\n', stderr);
GSL_ERROR_VAL ("unknown generator", GSL_EINVAL, 0);
}
fprintf (stderr, "GSL_RNG_TYPE=%s\n", gsl_rng_default->name);
}
else
{
gsl_rng_default = gsl_rng_mt19937;
}
p = getenv ("GSL_RNG_SEED");
if (p)
{
seed = strtoul (p, 0, 0);
fprintf (stderr, "GSL_RNG_SEED=%lu\n", seed);
};
gsl_rng_default_seed = seed;
return gsl_rng_default;
}
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