Author: Robert Hyatt
Date: 14:38:40 12/06/01
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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 didn't compute that number. I simply ran the test with two simple mods to the Evaluate() code so that if a pawn position is hashed, the score is saved and the EvaluatePawns() code is still executed. If the scores and other info don't match after this duplicated work, I produced an error and looked at the positions to make sure I didn't have a hashing bug I didn't know about. I was seeing an error 400K-500K nodes, on my PIII/750 laptop, which is about one error every 2 to 4 seconds. On my quad (I didn't run the test there as it was playing on ICC) this would turn into an error every second or less, which is not acceptable. Some positions produced _many_ errors per second, when there were fewer pieces so that more pawn moves were being searched...
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