Tim Peters <t...@python.org> added the comment:
>> In the 64-bit build there are no collisions across my >> tests except for 11 in the new tuple test. > That's pretty bad actually. With 64 bits, you statistically > expect something in the order of 10**-8 collisions. So > what you're seeing is 9 orders of magnitude too many collisions. You wrote the test, so you should remember that you throw away the top 32 bits of the 64-bit hash code :-) Tossing 345130 balls into 2**32 bins has an expected mean of 13.9 collisions and sdev 3.7. 11 collisions is fine. If I change the test to retain all the hash bits in the 64-bit build, there are no collisions in the new tuple test. If I change it again to retain only the high 32 hash bits, 27 collisions. Which is statistically suspect, but still universes away from "disaster" territory. ---------- components: +XML -Interpreter Core _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue34751> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
