Author: William Bryant
Date: 11:41:23 12/08/01
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On December 07, 2001 at 23:52:37, Robert Hyatt wrote: >On December 07, 2001 at 18:13:18, William Bryant wrote: > >> >>>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... >> >>I believe the thread was discussing the frequency of errors using a 32 pawn hash >>key which in previous threads you said that, after testing, produced no >>significant degree of collisions or errors. > > >This was a mistake on my part. My testing (no errors) was actually done several >times, but prior to my conversion to 32 bit signatures for pawn hashing. When I >tested this at David's urging, the number of collisions was ridiculous... I am >now using 64 bits again. > > > > >> >>If I read the above correctly, this implies that it does produce an unacceptable >>level of errors? >> >>Or is this above error rate discussing the main hash table using a 32 bit key? >> > >pawns only. as explained above. > > > >>Would you please clarify. >>Thank you. >> >>William OK, If the pawn hash table also hash to be indexed off of 64 bit zobrist numbers, but this is a completely separate table than the main hash table, then can a portion of the zobrist numbers used to create the main hash key be reused for creating the pawn hash key? example: instead of -- UInt64 ZTable[2][6][64]; //the integers for the main table UInt64 PZTable[2][64]; //the integers for the pawn table //using an additional 1K of memory (or catch) use-- UInt64 ZTable[2][6][64]; //the integers for the main table UInt64* PZTable = ZTable; //and reuse the numbers to save in catch Would this create problems? William
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