Computer Chess Club Archives




Subject: Re: Pattern Matching -- Avoiding Hand-Tuning

Author: Amir Ban

Date: 03:25:06 01/22/98

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On January 21, 1998 at 18:35:45, Stuart Cracraft wrote:

>Is there any good research done on pattern matching
>whole positions? What I'm thinking of is some measure
>for a position to determine how likely Joe-Schmoe master
>would be likely to move into this position.
>I still wish someone would post the method used by
>for the Deep Blue/Thought evaluation function tuning.
>Does anyone have a handle on what was done? It seems
>like a pretty good idea to avoid the human labor cost
>of hand-tuning.

The way I read the Athanamaran article, the results of the tuning were
not conclusive, and were not actually adopted into DT/DB.

I was already familiar with the idea of tuning by matching master moves,
and what I think the main interest in the article was the attempt to
formulate the evaluation mathematically so that it is suitable for
analytical optimization methods.

Years ago I had such a master-move match benchmark, and I ran it fairly
regularly. I became disillusioned with it and I don't run it any more.
It's simply too insensitive, governed by many irrelevant factors, and
today I'm sure that a program can improve by 100 rating points at least
without affecting the match score.

One thing that bothered me about that article is that they invested all
the effort in the wrong place. If I had a theory that some measure like
master-move matches reflects program strength, I would tweak a
parameter, see how it affects the measure, and do an independent test
such as a program self-test to see if the theory is right. A few such
experiments is all that is needed to prove or disprove the theory. Doing
multivariate least-squares optimization is nice, but if the theory is
correct, I may not need this to put it to good use, while if the theory
is not correct it's a complete waste of time. Of course, my method may
not make a Ph.D. thesis.

This is my standard answer to all the other optimization, genetic
algorithms and so on ideas: Forget about it for a moment and concentrate
on proving that your measure or theory works. Do the fancy stuff later,
though I think I can make good use of a proven measure even without it.


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