Author: Dan Homan
Date: 05:49:27 01/14/98
Go up one level in this thread
On January 13, 1998 at 14:43:16, Robert Hyatt wrote: >On January 13, 1998 at 09:08:49, Dan Homan wrote: >> >>p.s. My program does >> >>capture extensions (4/10 of a ply) > >dangerous one there. Ken Thompson used 1/2 ply in 1983, and probably >lost the 1983 World Championship as a result of doing this. He reported >it helped his WAC results quite a bit, but it costs about 1/2 to 1 ply. >He later discarded it totally. > > >>re-capture extensions (1 ply) >>check extensions (1 ply) >>pawn push extensions (1/2 ply or 1/3 ply) (endgame and late >>middle-game) >>bruce's mate ext. (1 ply) > >All reasonable. I am now using 3/4 ply for *everything* in Crafty, but >do allow multiple extensions to add together, with a limit of 1 ply. >This >actually improved the WAC results and seems to be running a good bit >faster >to reach the same depth... You said you allowed multiple extensions to add together with a limit of 1 ply. I assume this means that you do not allow left over fractions to roll over to the next ply. I tried eliminating the capture extension, it reduces my search tree by a factor of 2 in most positions so I get about 1 ply deeper in the same time. I solve some of the WAC positions a ply later, but the speedup generalizes to all positions. I ran overnight with the new version on FICS, and it doesn't seem any worse (it even gained 20 rating points). I'll probably write some analysis tools like Bruce suggested to get a more concrete measure of the change, but I am happy with a smaller search tree. :) - Dan
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.