Author: Gerd Isenberg
Date: 03:23:37 07/30/04
Go up one level in this thread
On July 29, 2004 at 16:32:11, Robert Hyatt wrote: >On July 29, 2004 at 14:09:13, Gian-Carlo Pascutto wrote: > >>On July 29, 2004 at 14:07:10, Robert Hyatt wrote: >> >>>On July 29, 2004 at 06:26:52, Gian-Carlo Pascutto wrote: >>> >>>>http://arxiv.org/ftp/cs/papers/0406/0406038.pdf >>>> >>>>I stumbled onto this when doing a search for Axon. >>>>Not seen it mentioned here yet. >>>> >>>>They also have a paper about hashing out which I can't >>>>download. >>>> >>>>-- >>>>GCP >>> >>> >>>Doesn't strike me as particularly interesting. IE it almost seems that they >>>don't realize that most programs store positions in a repetition list as 64 bit >>>Zobrist integers... >> >>Look at the hasing paper abstract, do some quick math, and you'll see they >>apparently don't know or don't use 64 bit hashing ;-) >> >>-- >>GCP > >I know. If this was published, I wonder where the referees were? ;) I found the algorithm rather smart. A few aspects: 1. They mention hash keys or part of hash keys at page 4/5. 2. They don't need hashkeys in game history as well in current searched move string as well. Only 16-bit moves. 3. The algorithm only needs a local concatination list of 25 16-bit words and is therefore much more memory friendly. 4. They don't have any problems with rare collisions, where the zobrist xor-sum of 2*N reversible moves is zero, but without a repetition. I use the idea of Ronald de Man as a precondition for a possible repetition, a small hashtable (2**12..14 bytes) indexed by some bits of the zobrist hashkey, see Van Kervinck's thesis: http://brick.bitpit.net/~marcelk/2002/marcelk-thesis.pdf 2.7 Implementation delails page 39. Gerd
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.