Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Hello from Edmonton (and on Temporal Differences)

Author: Russell Reagan

Date: 22:00:47 07/30/02

Go up one level in this thread


On July 30, 2002 at 22:43:36, James Swafford wrote:

>A natural follow up question (which I also asked) is -- then why isn't
>everyone doing it??

My first thought on this is that the top chess engines already have their
evaluation weights tuned very well. Perhaps not perfect. I think they are
putting their efforts into more beneficial things. For example, if your
evaluation function weights are 99% correct, then it's more beneficial to work
on a new pruning technique or add new evaluation factors, but tuning that almost
perfect evaluation function isn't going to produce any significant increases in
playing strength.

>Knightcap was strong, but it's
>definitely not in the top tier.

My thought on this is that just because an evaluation function's weights are
tuned to 100% perfection, it doesn't mean the engine will be strong. Maybe you
are evaluating the wrong things to begin with. If you only have material,
mobility, and king safety, then I suspect there is only so much tuning you can
do, and eventually you get optimal weights for each of those evaluation
parameters. Just because those are perfect, it doesn't mean the engine will be
among the top. If that program has a branching factor of 4, it's not likely that
it will ever compete with Fritz, Tiger, Shredder, Junior, etc., all of which
have much lower branching factors.

I think that is the main reason why you don't see (or hear) about TD in computer
chess very much. There are other things that will benefit the engine more. I
would think that even when a programmer reaches the end of his "to do" list,
that he would probably find it more beneficial to try and create completely new
pruning methods from scratch than to spend time working on implementing TD
evaluation tuning.

Russell



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.