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Subject: Re: Selecting among book moves

Author: Roberto Waldteufel

Date: 02:02:19 06/20/98

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On June 20, 1998 at 01:28:44, Don Dailey wrote:

>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

Hi Don,

Yes, this is something I never thought of doing. In my case it poses a curious
problem in that my program has a very different style of play to my own. Many of
the openings it uses are openings that I know comparatively little about, since
I never meet them in my own games (I always open 1.d4 with White, but my program
likes 1.e4 openings best). Since the program generally plays a bit better than I
do, and I don't always feel qualified to say what the best plan in an opening
is, so I have to rely on advice from publications and/or stronger players who do
use the openings in question, but then they do not always agree.

I like your idea in principle: it should enable the program to handle more and
more openings correctly, but I think there might be cases when you make a change
to the program that succeeds in improving its play in a particular opening
variation, while maybe having an adverse affect on its play in another
situation, and, what is worse, with a really big opening book it would be
impractical to test the change in all the lines, or even in a large selection of
them. I think this problem would make it quite difficult to actually know how
well the program tuning was working. The advantage of altering a single opening
variation rather than a single evaluation term in the program is that you know
that nothing else can change as a result, so you can more easily test whether
the change has helped or hindered the program.

Best wishes,

Roberto



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