1 files changed, 85 insertions, 0 deletions
diff --git a/gsl-1.9/rng/rand.c b/gsl-1.9/rng/rand.c
new file mode 100644
index 0000000..4c50a62
--- /dev/null
+++ b/gsl-1.9/rng/rand.c
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+/* rng/rand.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 <gsl/gsl_rng.h>
+
+/* This is the old BSD rand() generator. The sequence is
+
+   x_{n+1} = (a x_n + c) mod m 
+
+   with a = 1103515245, c = 12345 and m = 2^31 = 2147483648. The seed
+   specifies the initial value, x_1.
+
+   The theoretical value of x_{10001} is 1910041713.
+
+   The period of this generator is 2^31.
+
+   The rand() generator is not very good -- the low bits of successive
+   numbers are correlated. */
+
+static inline unsigned long int rand_get (void *vstate);
+static double rand_get_double (void *vstate);
+static void rand_set (void *state, unsigned long int s);
+
+typedef struct
+  {
+    unsigned long int x;
+  }
+rand_state_t;
+
+static inline unsigned long int
+rand_get (void *vstate)
+{
+  rand_state_t *state = (rand_state_t *) vstate;
+
+  /* The following line relies on unsigned 32-bit arithmetic */
+
+  state->x = (1103515245 * state->x + 12345) & 0x7fffffffUL;
+
+  return state->x;
+}
+
+static double
+rand_get_double (void *vstate)
+{
+  return rand_get (vstate) / 2147483648.0 ;
+}
+
+static void
+rand_set (void *vstate, unsigned long int s)
+{
+  rand_state_t *state = (rand_state_t *) vstate;
+
+  state->x = s;
+
+  return;
+}
+
+static const gsl_rng_type rand_type =
+{"rand",                        /* name */
+ 0x7fffffffUL,                  /* RAND_MAX */
+ 0,                             /* RAND_MIN */
+ sizeof (rand_state_t),
+ &rand_set,
+ &rand_get,
+ &rand_get_double};
+
+const gsl_rng_type *gsl_rng_rand = &rand_type;