Fixes #488. In rk_interval, use rk_random if the interval size is less than 2**32.

For 64-bit machines, this means results will agree with 32-bit machines,
and will be faster for these interval sizes (one less rk_random evaluation).

1 files changed, 8 insertions, 0 deletions

diff --git a/numpy/random/mtrand/randomkit.c b/numpy/random/mtrand/randomkit.c
index eddef16af..56f52c0b4 100644
--- a/numpy/random/mtrand/randomkit.c
+++ b/numpy/random/mtrand/randomkit.c
@@ -248,7 +248,15 @@ unsigned long rk_interval(unsigned long max, rk_state *state)
 #endif
 
 	/* Search a random value in [0..mask] <= max */
+#if ULONG_MAX > 0xffffffffUL
+	if (max <= 0xffffffffUL) {
+		while ((value = (rk_random(state) & mask)) > max);
+	} else {
+		while ((value = (rk_ulong(state) & mask)) > max);
+	}
+#else
 	while ((value = (rk_ulong(state) & mask)) > max);
+#endif
 
 	return value;
 }