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Subject: Re: Hash in quiescent search

Author: Mridul Muralidharan

Date: 00:51:29 11/26/03

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On November 25, 2003 at 22:19:04, macaroni wrote:

>is it usefull to use hash inside the quiescent search? if so, should one use a
>different table, smaller? larger? it is obvious that the quiescent hash cannot
>be used for actual returns in the main search, but perhaps it can be used for
>move ordering (there might be a large number of 'hits' form previous searches).
>And I supose the main search hash can be used in the qsearch too if desired. Is
>this all worth the memory? (and time for lookups and stores), or would I do
>better to use my memory on say, another hash table insearch so I can have better
>replacement schemes?
>thanks

Hi,

  In mess , I use a seperate table same size as the main transpos table in
QSearch. This holds the best move , score and bounds.

Main reasons why you could do this are :

1) Since I do checks , threatening moves and all check evasions , it helps me
immensively - both in move ordering and also by giving me cutoffs (much lower
though).
2) You could also use this same table to also store the evaluation of the
position - thereby saving an expensive eval() call !
note : assuming no search tree path dependent terms in eval - if yes , you could
split the eval() into only position dependent and rest (path dependent)
components and store the position dependent stuff into the table.

Currently I follow always replace multiprobe , with positions near depth == 0
getting slightly higher precedence - you could do it different though ...
As always , YMMV

Regards
Mridul



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