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Subject: Re: Extended futility pruning and hashtables

Author: Vincent Diepeveen

Date: 08:53:04 12/31/99

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On December 30, 1999 at 13:10:08, Gian-Carlo Pascutto wrote:

>Hi all,
>
>I've just been reading Ernst Heinz's paper on extended futility
>pruning and I have some questions:
>
>a) where does the quiescent search fit in all this ? Should I just
>assume that using a quiescent search is equal to statically evaluating
>the position ? I.e. are 'horizon nodes' the ones at the end of the
>standard search or those at the end of the quiescent search ? I am
>already using futility pruning in the quiescent search and I don't
>understand how this relates to the kind of futility pruning that's
>described by Heinz. They seem indentical to me, except that, well,
>mine is done in the qsearch and what Heinz describes looks like doing
>it in the standard search.
>
>b) I understand that just storing the values into the transposition table is
>deadly (e.g. having to research after a fail-low would yield garbage), and
>this is mentioned in the paper, but how should this optimally be handled then ?
>Just not storing anything in the ttable seems rather radical.

Indeed. The more efficient your search is (so the smaller your fliprate
which i defined as the chance that a node which was stored as < beta
in transpositiontable now becomes >= beta), the less likely such
dubious things as futitily pruning will work for you.

Vincent

>--
>GCP



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