X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Frandom.c;h=7420a82ecee8392e0658f5026aa0221b2e50f384;hb=e210b20bf6f405637c8c03dd280b5a4a627191b8;hp=0352b602bb585a1b0e48ea95774aa1b0f36a87e8;hpb=def7e6026513a3ee7c2b38416b30a2e890e34311;p=pspp

diff --git a/src/random.c b/src/random.c
index 0352b602bb..7420a82ece 100644
--- a/src/random.c
+++ b/src/random.c
@@ -1,5 +1,5 @@
 /* PSPP - computes sample statistics.
-   Copyright (C) 1997-9, 2000 Free Software Foundation, Inc.
+   Copyright (C) 1997-9, 2000, 2005 Free Software Foundation, Inc.
    Written by Ben Pfaff <blp@gnu.org>.
 
    This program is free software; you can redistribute it and/or
@@ -14,234 +14,44 @@
 
    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., 59 Temple Place - Suite 330, Boston, MA
-   02111-1307, USA. */
+   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+   02110-1301, USA. */
 
 #include <config.h>
 #include "random.h"
-#include <assert.h>
-#include <inttypes.h>
-#include <limits.h>
-#include <math.h>
-#include <stdlib.h>
 #include <time.h>
-#include "alloc.h"
-#include "magic.h"
-#include "settings.h"
+#include "xalloc.h"
 
-/* Random number generator. */
-struct rng 
-  {
-    /* RC4-based random bytes. */
-    uint8_t s[256];
-    uint8_t i, j;
+static gsl_rng *rng;
 
-    /* Normal distribution. */
-    double next_normal;
-  };
-
-
-/* Return a `random' seed by using the real time clock */
-unsigned long
-random_seed(void)
-{
-  time_t t;
-  
-  time(&t);
-
-  return (unsigned long) t;
-}
-
-/* Creates a new random number generator, seeds it based on
-   the current time, and returns it. */
-struct rng *
-rng_create (void) 
-{
-  struct rng *rng;
-  static unsigned long seed=0;
-  unsigned long s;
-
-  rng = xmalloc (sizeof *rng);
-
-
-  if ( seed_is_set(&s) ) 
-    {
-      seed = s;
-    }
-  else if ( seed == 0 ) 
-    {
-      seed = random_seed();
-    }
-  assert(seed);
-  /* 
-  if (t == 0 || set_seed_used)
-  {
-    if (set_seed == NOT_LONG) 
-      time (&t);
-    else
-      t = set_seed;
-    set_seed_used=0;
-  }
-  else
-    t++;
-  */
-  rng_seed (rng, &seed, sizeof seed);
-  rng->next_normal = NOT_DOUBLE;
-  return rng;
-}
-
-/* Destroys RNG. */
 void
-rng_destroy (struct rng *rng) 
-{
-  free (rng);
-}
-
-/* Swap bytes. */
-static void
-swap_byte (uint8_t *a, uint8_t *b) 
+random_init (void) 
 {
-  uint8_t t = *a;
-  *a = *b;
-  *b = t;
 }
 
-/* Seeds RNG based on the SIZE bytes in BUF.
-   At most the first 256 bytes of BUF are used. */
 void
-rng_seed (struct rng *rng, const void *key_, size_t size) 
+random_done (void) 
 {
-  const uint8_t *key = key_;
-  size_t key_idx;
-  uint8_t *s;
-  int i, j;
-
-  assert (rng != NULL);
-
-  s = rng->s;
-  rng->i = rng->j = 0;
-  for (i = 0; i < 256; i++) 
-    s[i] = i;
-  for (key_idx = 0, i = j = 0; i < 256; i++) 
-    {
-      j = (j + s[i] + key[key_idx]) & 255;
-      swap_byte (s + i, s + j);
-      if (++key_idx >= size)
-        key_idx = 0;
-    }
+  if (rng != NULL) 
+    gsl_rng_free (rng);
 }
 
-/* Reads SIZE random bytes from RNG into BUF. */
-void
-rng_get_bytes (struct rng *rng, void *buf_, size_t size) 
+/* Returns the current random number generator. */
+gsl_rng *
+get_rng (void)
 {
-  uint8_t *buf = buf_;
-  uint8_t *s;
-  uint8_t i, j;
-
-  assert (rng != 0);
-
-  s = rng->s;
-  i = rng->i;
-  j = rng->j;
-  while (size-- > 0) 
-    {
-      i += 1;
-      j += s[i];
-      swap_byte (s + i, s + j);
-      *buf++ = s[(s[i] + s[j]) & 255];
-    }
-  rng->i = i;
-  rng->j = j;
-}
-
-/* Returns a random int in the range [0, INT_MAX]. */
-int
-rng_get_int (struct rng *rng) 
-{
-  int value;
-
-  do 
-    {
-      rng_get_bytes (rng, &value, sizeof value);
-      value = abs (value);
-    }
-  while (value < 0);
-   
-  return value;
-}
-
-/* Returns a random unsigned in the range [0, UINT_MAX]. */
-unsigned
-rng_get_unsigned (struct rng *rng) 
-{
-  unsigned value;
-
-  rng_get_bytes (rng, &value, sizeof value);
-  return value;
-}
-
-/* Returns a random number from the uniform distribution with
-   range [0,1). */
-double
-rng_get_double (struct rng *rng) 
-{
-  for (;;) 
-    {
-      unsigned long ulng;
-      double dbl;
-  
-      rng_get_bytes (rng, &ulng, sizeof ulng);
-      dbl = ulng / (ULONG_MAX + 1.0);
-      if (dbl >= 0 && dbl < 1)
-        return dbl;
-    }
-}
-
-/* Returns a random number from the distribution with mean 0 and
-   standard deviation 1.  (Multiply the result by the desired
-   standard deviation, then add the desired mean.) */
-double 
-rng_get_double_normal (struct rng *rng)
-{
-  /* Knuth, _The Art of Computer Programming_, Vol. 2, 3.4.1C,
-     Algorithm P. */
-  double this_normal;
-  
-  if (rng->next_normal != NOT_DOUBLE)
-    {
-      this_normal = rng->next_normal;
-      rng->next_normal = NOT_DOUBLE;
-    }
-  else 
-    {
-      double v1, v2, s;
-      
-      do
-        {
-          double u1 = rng_get_double (rng);
-          double u2 = rng_get_double (rng);
-          v1 = 2.0 * u1 - 1.0;
-          v2 = 2.0 * u2 - 1.0;
-          s = v1 * v1 + v2 * v2;
-        }
-      while (s >= 1);
-
-      this_normal = v1 * sqrt (-2. * log (s) / s);
-      rng->next_normal = v2 * sqrt (-2. * log (s) / s); 
-    }
-  
-  return this_normal;
+  if (rng == NULL)
+    set_rng (time (0));
+  return rng;
 }
 
-/* Gets an initialized RNG for use in PSPP transformations and
-   procedures. */
-struct rng *
-pspp_rng (void)
+/* Initializes or reinitializes the random number generator with
+   the given SEED. */
+void
+set_rng (unsigned long seed) 
 {
-  static struct rng *rng;
-
+  rng = gsl_rng_alloc (gsl_rng_mt19937);
   if (rng == NULL)
-    rng = rng_create ();
-  return rng;
+    xalloc_die ();
+  gsl_rng_set (rng, seed);
 }