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Subject: Re: Mobility in Chess Evaluation Function at terminal-nodes

Author: David Dahlem

Date: 16:56:16 12/28/05

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<snip>

>The idea works like this:
>Suppose that I evaluate a pawn as 100.0 centipawns.  How much should a knight be
>worth?  Probably somewhere between 200 and 500 centipawns.  Now, if I choose a
>bad value (like 200 centipawns) then I should solve less problems.  If I choose
>a good value (probably fairly close to 300), then I will solve more problems.
>So I iterate over 12,000 quiet chess positions with known solutions and see what
>value of the parameter gives me the most solutions.
>
>Now, the value found will NOT be optimal for play.  But it will be a good
>starting point for experimentation.  And I will also have a pretty good idea
>about what sort of range will produce reasonable results.
>

Thanks Dann. I'm not really a fan of tuning with test suites. I just build
several test versions with different bonus values, and run a lot of test games.
It's time consuming, but i have more confidence in the results. :-)

Regards
Dave

>So...
>
>Big_again:
>Tell the program that a knight is worth 'start' (e.g. 200) centipawns.
>Have it try to solve 12000 positions at depth k.
>Count the solutions.
>
>Little_again:
>Tell the program that a knight is worth Current Knight value + Increment
>centipawns.
>Have it try to solve 12000 positions at depth k.
>Count the solutions.
>
>If current knight value is bigger than 'limit' (e.g 500) goto Little_again
>
>Fit the curve and write the solution. (We are interested in the apex of a
>parabola that has only a maximum and not a minimum.)
>
>If depth is not at maximum desired depth, increment depth 'k' and goto Big_again



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