Author: Steven Edwards
Date: 09:04:45 05/12/05
Go up one level in this thread
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).
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