Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: ProbCut: An Effective Selective Extension of the Alpha-Beta Algorith

Author: Robert Hyatt

Date: 19:19:47 07/21/04

Go up one level in this thread


On July 21, 2004 at 19:51:21, Ed Trice wrote:

>Actually, ProbCut worked best when applied to the game of Othello (reversi).
>There is another variation of ProbCut called Multi-ProbCut (MPC) which was
>hooked up to the Crafty version you mentioned.
>
>The gain was minimal, but it was measureable and it did help the program's
>performance.

It wasn't a gain in my testing.  I set up crafty vs MPC-crafty and played a
_bunch_ of games on the older quad cluster.  MPC was somewhat worse in every
test I tried.  Way worse in fast games, but worse overall, period.

That's why it is not in the released versions...


>
>But, there was also a big change in crafty since that time to correct some bad
>passed pawn code.
>
>[D] 8/7p/8/4pp1k/8/r6P/P5R1/6K1 b - -
>
>Before Crafty 19.13, Black to move would show ...Rxj3?? with a big positive
>score, which loses on the c-pawn is launched.
>
>If you use Crafty 19.13 or later, you shoud see it instantly avoiding this line
>of play altoether.
>
>I just mention this since if you do download the older crafty with MPC hooked
>up, make sure you change the most-recent split_passed_pawn stuff.
>
>>Hi,
>>
>>This is probably old news to many, but I ran across the pages of Michael Buro
>>(http://www.cs.ualberta.ca/~mburo/), and saw an article on ProbCut, highly
>>recommending it, and even mentioning its inclusion in a version of Crafty 18.15.
>>
>>"ProbCut works in chess on top of null-move search! Download
>>mpc_crafty_18.15.tgz to play with it. We encourage all chess programmers to
>>experiment with ProbCut!"
>>
>>One can download the article "ProbCut: An Effective Selective Extension of the
>>Alpha-Beta Algorithm" on his page of publications
>>(http://www.cs.ualberta.ca/~mburo/publications.html) as well as a follow-up
>>article "A.X. Jiang and M. Buro, First Experimental Results of ProbCut Applied
>>to Chess", Proceedings of the Advances in Computer Games Conference 10, Graz
>>2003.
>>
>>For new programmers looking for material, this is certainly one, plus it might
>>be added to the links in the Computer Chess Resource Center.
>>
>>                                    Albert



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.