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- /* rng/default.c
- *
- * Copyright (C) 1996, 1997, 1998, 1999, 2000, 2007 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 3 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 "gsl__config.h"
- #include <stdlib.h>
- #include <stdio.h>
- #include <string.h>
- #include "gsl_rng.h"
- #include "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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