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Subject: Re: Book learning question

Author: Robert Hyatt

Date: 09:03:29 05/20/02

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On May 19, 2002 at 18:00:02, Roy Brunjes wrote:

>
>I wonder how book learning is implemented in various commercial chess programs
>on the market.  Has this been discussed before?  If so, can someone point me to
>a link here at CCC about this topic?
>
>As an example:  Program X plays the Ruy Lopez (as White) vs an opponent.  Let's
>say that the game was played at Game in 30 minutes.  The program ultimately
>loses the game after 75 moves.  With book learning, will it refuse to open 1. e4
>ever again (assuming the program is set to never repeat an opening line it loses
>with)?  Does the time control of that game get noted in the book learning
>process?  If a program is unable to win with a line at game in 30 minutes, who
>knows if it might do better at Game in 5 minutes with the same line, or game in
>2 hours instead?

If you are an ICCA member, you can find a copy of a paper I wrote on book
learning there.  What I do is pretty similar to what anybody has to do if they
implement book learning.  The "weights" might be different, but the overall
approach is pretty well-defined and straightforward.

If you aren't an ICCA member, I think I have an electronic (ASCII) version I
could send.



>
>With a defeat on its record with 1. e4 ... how does it know that the source of
>its defeat was, perhaps 2. Nf3 (after 1 ... e5 by Black).  Or does it assume
>that the 22nd move (I'm pulling that number out of the air for this example),
>which is the last book move it has, is the offending move and the program will
>willingly repeat that line up to move 22 and then vary (either select another
>book move if there is one, or if there is not another book move at that point,
>just start thinking in hopes of finding a better move on its own)?
>
>And, if that deviation from book (i.e. avoiding the known "bad" 22nd move in its
>book) results in another defeat, does the program then mark the 21st move in its
>book as suspect -- and so on ... working its way back up toward 1. e4 only after
>a huge number of games is played (all of which in my contrived example) lead to
>losses for the program?
>
>Also, do programs learn differently if they are White with a given opening line
>vs if they are Black in the same opening line?
>
>Yes, I realize that there are probably many different ways to implement book
>learning, but hopefully my example if generic enough that someone can describe a
>plausible way to handle it, even if no specific programmer for any single
>commercial product responds to my questions.
>
>Thanks for your thoughts,
>
>Roy



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