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Subject: Re: Counter move heuristic

Author: Gian-Carlo Pascutto

Date: 04:55:27 08/30/05

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On August 30, 2005 at 07:50:42, Alvaro Jose Povoa Cardoso wrote:

>Hi,
>could someone please explain how to implemement the counter move heuristic?
>I first red it in the Marcel Kervinck master thesis pdf document, but didn't
>understand it, here is the citation:
>
>"The counter move heuristic works by observing that killers need not be
>constrained by sharing the same parent node. Often, a single move, defined as
>(from,to)-tuple would generate the same refutation.
>Counter moves are easily implemmented using a 64x64 table that can hold the
>counter moves and that is indexed with the previous move."
>
>(I couldn't copy and paste so I typed in the text)

You keep an array of 64 x 64 elements, which stores moves.

Each time you get a beta cutoff (a refutation), you store the current move into
the element indexed by the previous move (along the path).

Use the countermove as an addition to the killermoves in move ordering.

--
GCP



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