1 files changed, 92 insertions, 0 deletions
diff --git a/gsl-1.9/rng/coveyou.c b/gsl-1.9/rng/coveyou.c
new file mode 100644
index 0000000..8732990
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+++ b/gsl-1.9/rng/coveyou.c
@@ -0,0 +1,92 @@
+/* rng/coveyou.c
+ * 
+ * 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.
+ */
+
+/*
+ * This generator is taken from
+ *
+ * Donald E. Knuth
+ * The Art of Computer Programming
+ * Volume 2
+ * Third Edition
+ * Addison-Wesley
+ * Section 3.2.2
+ *
+ * This implementation copyright (C) 2001 Carlo Perassi
+ * and (C) 2003 Heiko Bauke.
+ * Carlo Perassi reorganized the code to use the rng framework of GSL.
+ */
+
+#include <config.h>
+#include <stdlib.h>
+#include <gsl/gsl_rng.h>
+
+#define MM 0xffffffffUL         /* 2 ^ 32 - 1 */
+
+static inline unsigned long int ran_get (void *vstate);
+static double ran_get_double (void *vstate);
+static void ran_set (void *state, unsigned long int s);
+
+typedef struct
+{
+  unsigned long int x;
+}
+ran_state_t;
+
+static inline unsigned long int
+ran_get (void *vstate)
+{
+  ran_state_t *state = (ran_state_t *) vstate;
+
+  state->x = (state->x * (state->x + 1)) & MM;
+
+  return state->x;
+}
+
+static double
+ran_get_double (void *vstate)
+{
+  ran_state_t *state = (ran_state_t *) vstate;
+
+  return ran_get (state) / 4294967296.0;
+}
+
+static void
+ran_set (void *vstate, unsigned long int s)
+{
+  ran_state_t *state = (ran_state_t *) vstate;
+
+  unsigned long int diff = ((s % 4UL) - 2UL) % MM;
+
+  if (diff)
+    state->x = (s - diff) & MM;
+  else
+    state->x = s & MM;
+
+  return;
+}
+
+static const gsl_rng_type ran_type = {
+  "coveyou",                    /* name */
+  MM-1,                         /* RAND_MAX */
+  2,                            /* RAND_MIN */
+  sizeof (ran_state_t),
+  &ran_set,
+  &ran_get,
+  &ran_get_double
+};
+
+const gsl_rng_type *gsl_rng_coveyou = &ran_type;