Replaced arbitrary addend in tuple_hash with one that is known to generate
many more prime multipliers and that performs well on collision tests.
diff --git a/Objects/tupleobject.c b/Objects/tupleobject.c
index 4cb80f0..ff20b43 100644
--- a/Objects/tupleobject.c
+++ b/Objects/tupleobject.c
@@ -256,6 +256,14 @@
return result;
}
+/* The addend 82520, was selected from the range(0, 1000000) for
+ generating the greatest number of prime multipliers for tuples
+ upto length eight:
+
+ 1082527, 1165049, 1082531, 1165057, 1247581, 1330103, 1082533,
+ 1330111, 1412633, 1165069, 1247599, 1495177, 1577699
+*/
+
static long
tuplehash(PyTupleObject *v)
{
@@ -270,7 +278,7 @@
if (y == -1)
return -1;
x = (x ^ y) * mult;
- mult += 69068L + len + len;
+ mult += 82520L + len + len;
}
if (x == -1)
x = -2;