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Subject: Re: Size of PawnHashTable

Author: Tony Werten

Date: 13:08:49 11/07/02

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On November 07, 2002 at 15:55:29, Martin Bauer wrote:

>Hello,
>
>i have implemented PawnHashTables in my engine. Is there any rule for the size
>of the table? I think about rules like:
>
> - 50% usage when calculating to depth 10

Somewhere from 8Mb you will get a 99,9% hitrate after a few seconds.

>
>or something like that.
>
>Any ideas?
>
>My second problem:
>
>How important is it to be exact? My pawn evaluation depends not only on the
>strukture of the pawns, but also on development, position of rooks in a samll
>amount. At the moment I dont take care of that, my hashkeys depend only on the
>position of pawns. Is it acceptable not to be absolutely exact?

No. Best is to put only the pawnstuff in the pawnhashtable (hence the name ) and
do the rookstuff dynamicly. If you put in the hashtable fe wich files have
doublepawns, passed pawns and isolated pawns, you can use that when doing the
rookstuff.

Pawnhashtables are best for putting the pawnstructures into more manageable
variables that can be used for the evaluation. The hashtable itself doesn't have
to contain any evaluation ( though it can )

>Are the top
>engines doing such simplifications?

No, it kills you in endgames.

Tony

>
>Regards
>
>Martin



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