Author: David Blackman
Date: 01:51:27 09/16/99
Go up one level in this thread
On September 16, 1999 at 04:00:43, Tom Kerrigan wrote: >If you have a program with 64 bit hash keys, is it a good idea to devote n bits >to pawns and the rest to pieces and side-to-move? If you need a pawn hash for fast pawn eval, and a full hash for transpositions etc, then calculating them both into one 64 bit quantity probably makes things a bit faster. However it increases the probability of various kinds of false matches. I think it will probably work out ok, but be careful. You might want calculate an additional 64 bits just for testing purposes so you can count how many false matches you get from the first 64. This would be turned off when you have to run fast of course. >I was thinking a good balance may be 24 bits for pawns, but I have no data to >back this up. Does anybody else? > >-Tom Pawns make up about half the pieces on the board, and a little less than half the information content (because there are 2 sorts of pawns and 10 sorts of other pieces), so i guess about 24 to 30 bits for the pawns is the right proportion.
This page took 0.01 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.