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Subject: Re: Selecting among book moves

Author: Don Dailey

Date: 22:28:44 06/19/98

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On June 19, 1998 at 23:40:17, Roberto Waldteufel wrote:

>
>On June 19, 1998 at 15:55:13, Steven J. Edwards wrote:
>
>>On June 19, 1998 at 15:04:21, Tim Mirabile wrote:
>>
>>>I've never been a big fan of this method.  Even high level games tend to have
>>>results which do not necessarily indicate who played best in the opening.  But
>>>it's hard to suggest another method that does not involve a lot of hand tuning.
>>>Perhaps you could just suck in all of ECO and Informant, with evaluations, which
>>>if not totally trustworthy would be more so than game results.
>>
>>I dislike the uniform distribution method mostly because it seems that a lot of
>>information is being thrown away.  But I also dislike the ECO/Informator
>>transcription (I hear these can be had on CD-ROM nowadays) because it is
>>particularly vunerable to attack by typo hunters who peruse the source input.
>>Additionally, the Informator evaluations are really not scalars and some sort of
>>multivariate weighting function would have to be used.  And so we're back to the
>>same type of problem as with weighting win/draw/loss results.
>>
>>I can think of ways to have a program tune its own book from PGN input files,
>>but they all involve playing through the lines with heavy duty analysis to
>>locate variations which conform to the program's search and evaluation.
>>
>>One idea I've considered is getting a couple of books with titles like _White to
>>Play and Win, a Complete Opening Strategy for the Attacking Player_ and just
>>copying the variations into the program's book.  I think that a 5,000 move book
>>would suffice for this, but once the opposition figured out what was going on,
>>then it would be time for another book.
>>
>>-- Steven (sje@mv.mv.com)
>
>Hi Steven,
>
>I have often pondered this question, and like you I have failed to find a
>satisfactory answer. In the end, I don't think that mere vollume is an adequate
>replacement for chess judgement. Probably the most effective way to build an
>openings book is to do it by hand, but this is, as you know, very slow and
>tedious. Your suggestion about using opening repertoire publications is quite
>similar to my approach, but there is something that I might suggest you try in
>order to help in your selection. The openings should be chosen with great care
>to compliment the strengths and weaknesses of your program. Ideally you want
>openings that, although they may not confer an objective advantage, lead to
>positions that your program handles well. If your program is best in very
>tactical positions, you might consider giving it some sharp gambit lines to play
>for example. When you have just entered a new line of play, say for White, try
>letting the program play against itself. Does White win? If so, your choice was
>well founded. If White loses, you either have to supply more variations to "plug
>the knowlege gap", or else you scrap the whole line and substitute something
>else instead. In this way, you can slowly build an opening book that is tailored
>to your particular program, which I think is also similar to the way that a
>strong human player chooses an opening repertoire. I hope you find the idea
>useful,
>
>Roberto

Hi Roberto,

I think your idea has much merit.  I've always advocated picking lines
that suit the programs style.  Playing the program against itself
might give some clues about how good the choice is.

I would like to suggest another approach, one that I rarely use but
I think also has merit.  We all tend to constantly adjust the
book and much has been posted on this subject from Bob and others
including myself.  But maybe we should consider the possiblility
of adjusting the program to the book instead (or in addition to)
adjusting the book to the program?   There have been times when
Cilkchess comes right out of book and quickly makes a positional
error or weak move.  I have sometimes fixed the cause of the
error since I know there is a problem.  I usually then also
fix the book just to be on the safe side.   In principle we
have two "knobs to turn" not just one.

If it's a more general case of the program just not understanding
the opening ideas then I still think it might be an opportunity
to improve your program instead of just ignoring the problem by
tunning the book.

I believe the hardest program to beat would be the one with a
big wide opening book where the program plays each system
reasonably well.  Building one of these of course is no easy
task!

- Don












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