#include <config.h>
#include "random.h"
-#include <assert.h>
+#include "error.h"
#include <inttypes.h>
#include <limits.h>
#include <math.h>
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 time_t t;
+ static unsigned long seed=0;
+ unsigned long s;
rng = xmalloc (sizeof *rng);
- if (t == 0)
- time (&t);
+
+
+ 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, &t, sizeof t);
+ */
+ rng_seed (rng, &seed, sizeof seed);
rng->next_normal = NOT_DOUBLE;
return rng;
}
double
rng_get_double (struct rng *rng)
{
- unsigned long value;
-
- rng_get_bytes (rng, &value, sizeof value);
- return value / ULONG_MAX;
+ 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