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Subject: Re: "It's alive, I tell you! It's alive!"

Author: Michael Yee

Date: 11:36:22 05/12/05

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On May 12, 2005 at 12:04:45, Steven Edwards wrote:
>On May 12, 2005 at 11:05:46, Michael Yee wrote:
>
>>The gist of my question was essentially : what were the *chess* features like?
>>
>>For example, did each chromosome somehow select/"design" its own
>>features/patterns from some feature space:
>>
>>- feature1 : >= 1 slider piece in same file as opponent king
>>- feature2 : <= 2 flight squares for opponent king
>>- feature3 : >= 2 pieces attacking h7
>>- etc.
>>
>>Or did each chromosome just have weights for some pre-defined features (similar
>>to a linear static evaluation function)?
>>
>>- kingDefenseWeight = 0.8
>>- pawnShieldWeight = 0.5
>>- etc.
>>
>>Option 2 is unlikely since you could fit those without using GAs. So my main
>>question was : what was the space of possible features?
>
>A microfeature is a easily recognized pattern without instance variables.
>Currently, thery are hardcoded but this is subject to change.  A species is a
>template made from a subet of the available microfeatures.  (Only the MateAttack
>species is being developed at the moment.)  Here is the microfeature list used
>in the first experiment:
>
>
>(defconstant MateAttackMfSymbolVec
>  (make-vector-by-content
>    '(
>      MfAdjCheck
>      MfAdjDefenderCapture
>      MfAdjDefenderDecoy
>      MfCapture
>      MfCheck
>      MfDiscoveredCheck
>      MfDoesCheckmate
>      MfDoesMateIn2
>      MfDoubleCheck
>      MfFlightDecrease
>      MfFlightIncrease
>      MfForceCEInterposition
>      MfForceCEKingNoncapture
>      MfNoCheck
>      MfResponseCountEq1
>      MfResponseCountEq2
>      MfResponseCountGt4
>      MfResponseCountLe4
>      MfThreatenMateIn1
>      MfThreatenMateIn2
>    )))
>
>Your option two is fairly close to describing the initial experiment.  However,
>I'm working on the automated synthesis of new genes produced from conjunctive
>normal form expressions of existing ones.
>
>The merit calculation in the initial experiment is simple: it's the total best
>move match count of the training test suite.  The next revision here will be to
>measure the average raw weight total distances between rankings of best moves
>and non-best move groups summed over all the positions.  This is needed for
>several tastsk, one of them being the ability to understand thresholds (how many
>mating attack moves exist, and is a mating attack justified at the current
>exploration effort level).

Thanks for the explanation. Your "templates" sound like subset selection, which
is certainly a harder problem then just learning weights.

Overall, your approaches sound very interesting and seem to go beyond what's
been done before. For example, move ordering has been studied a lot, but I don't
think it's been studied in a situation/plan-specific way (like move
ordering/selection during a mating attack plan).

Michael



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