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Subject: Re: Move ordering question

Author: Pham Minh Tri

Date: 06:06:35 01/05/02

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[snip]
>
>Crafty generates moves in two passes...  It first generates just captures/
>promotions, and if the good ones of those don't produce a fail high, it
>generates the rest of the moves.  I try the moves in the following order:
>
>1.  hash move prior to generating _anything_.
>
>2.  captures that appear to _win_ material (SEE order) followed by captures
>that appear to break even.
>
>3.  two killer moves (these are non-captures _always_ and are tried before
>generating any non-capture moves).
>
>4.  four "history" moves (history heuristic).

Bob, which version of Crafty do you use four history moves? I found that the
lastest one (18.12) you used only two ;)

A question: Which one do you think is better: generate non-capture before
history moves or do the history moves (and check if they are valid like checking
hash move) before generating non-capture moves?

>
>5.  remainder of the moves including losing captures in the order they are
>in the list...
>
>Those are good enough to produce the fail-high condition on the first move
>92-94% of the time.  Anything over 90% qualifies as a "strongly-ordered
>game tree."



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