Author: Robert Hyatt
Date: 20:49:58 12/08/01
Go up one level in this thread
On December 08, 2001 at 19:06:48, Pham Minh Tri wrote: >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. >> > >Do you think 64 bits hashkey for pawntable still speeds up program? or is it >better to not use? > >In my case, a simple pawn code program, use 64bits hash for pawn is slower than >not use (because I could save much time for making hashkeys, probing and >entering table). I am curious about others. > > I can't imagine an eval so simple that a 64 bit signature update would be slower. You only update the signature on a pawn move or pawn capture, which is a small part of the tree normally. In any case, it does appear that using 32 bits is asking for trouble no matter how simple your eval... > >> >>> >>>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
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