Author: Frank Phillips
Date: 11:57:52 12/07/01
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On December 06, 2001 at 21:13:35, Dan Newman wrote: >On December 06, 2001 at 17:29:43, Severi Salminen wrote: > >>Hi >> >>How many collisions crafty gets on average using 32-bit keys? So how many nodes >>Crafty searchs on average to get 1 collision? I'm now using plain Visual C++ 6.0 >>rand() with no hamming distance tests and I get about 80 collisions out of >>10'000'000 evaluations from initial position. I'd like to know if that is more >>or less than Robert and David were seeing. Funny thing was that first I searched >>about 5'000'000 nodes with no collisions, then I saw 40 collisions in a short >>time, then again no collisions and finally 40 more in a short time. >> >>Severi > >I did this test on my program, Shrike, and got 62 collisions out of >66 million pawn hash probes with a 32-bit hash code, so I get about >1 collision per million probes. This was on the WAC test suite and >so may vary in actual games... > >-Dan. I store the lower 32bits as the hash key and use (some of) the top bits as the index. This is effectively more than 32bits, but I feel I now feel the need to check it is enought. How did you test for clashes: did you store the board along with the hash entry and check that the position on the board and stored board were the same - or is there a smarter way? Frank
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