Author: Robert Hyatt
Date: 06:44:56 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? > >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 If you are going to use them independently to probe tables (ie using the 24 bits to probe the pawn hash table) then this won't work well. 24 bits is only 16 million possibilities... that will get more than a few collisions. And the same for the upper 40 bits and pieces. I know that 32 bits is not enough for normal hashing. Stanback/I ran a bunch of tests years ago in a discussion on r.g.c.c and we got collisions by the bucketload with 32 bit keys. 64 was totally safe back then, although speeds are way up now compared to then. I am using a 32 bit pawn hash signature, but a full 64 bit total hash signature.
This page took 0 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.