1 files changed, 130 insertions, 0 deletions
diff --git a/gsl-1.9/rng/ran1.c b/gsl-1.9/rng/ran1.c
new file mode 100644
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+++ b/gsl-1.9/rng/ran1.c
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+/* rng/ran1.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 an implementation of the algorithm used in Numerical
+   Recipe's ran1 generator.  It is MINSTD with a 32-element
+   shuffle-box. */
+
+static inline unsigned long int ran1_get (void *vstate);
+static double ran1_get_double (void *vstate);
+static void ran1_set (void *state, unsigned long int s);
+
+static const long int m = 2147483647, a = 16807, q = 127773, r = 2836;
+
+#define N_SHUFFLE 32
+#define N_DIV (1 + 2147483646/N_SHUFFLE)
+
+typedef struct
+  {
+    unsigned long int x;
+    unsigned long int n;
+    unsigned long int shuffle[N_SHUFFLE];
+  }
+ran1_state_t;
+
+static inline unsigned long int
+ran1_get (void *vstate)
+{
+  ran1_state_t *state = (ran1_state_t *) vstate;
+
+  const unsigned long int x = state->x;
+
+  const long int h = x / q;
+  const long int t = a * (x - h * q) - h * r;
+
+  if (t < 0)
+    {
+      state->x = t + m;
+    }
+  else
+    {
+      state->x = t;
+    }
+
+  {
+    unsigned long int j = state->n / N_DIV;
+    state->n = state->shuffle[j];
+    state->shuffle[j] = state->x;
+  }
+
+  return state->n;
+}
+
+static double
+ran1_get_double (void *vstate)
+{
+  float x_max = 1 - 1.2e-7f ; /* Numerical Recipes version of 1-FLT_EPS */
+
+  float x = ran1_get (vstate) / 2147483647.0f ;
+ 
+  if (x > x_max) 
+    return x_max ;
+  
+  return x ;
+}
+
+
+static void
+ran1_set (void *vstate, unsigned long int s)
+{
+  ran1_state_t *state = (ran1_state_t *) vstate;
+  int i;
+
+  if (s == 0)
+    s = 1;      /* default seed is 1 */
+
+  for (i = 0; i < 8; i++)
+    {
+      long int h = s / q;
+      long int t = a * (s - h * q) - h * r;
+      if (t < 0)
+        t += m;
+      s = t;
+    }
+
+  for (i = N_SHUFFLE - 1; i >= 0; i--)
+    {
+      long int h = s / q;
+      long int t = a * (s - h * q) - h * r;
+      if (t < 0)
+        t += m;
+      s = t;
+      state->shuffle[i] = s;
+    }
+
+  state->x = s;
+  state->n = s;
+
+  return;
+}
+
+static const gsl_rng_type ran1_type =
+{"ran1",                        /* name */
+ 2147483646,                    /* RAND_MAX */
+ 1,                             /* RAND_MIN */
+ sizeof (ran1_state_t),
+ &ran1_set,
+ &ran1_get,
+ &ran1_get_double};
+
+const gsl_rng_type *gsl_rng_ran1 = &ran1_type;