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Subject: Re: Pawn hashing without Zobrist keys

Author: Dieter Buerssner

Date: 11:58:35 09/12/03

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On September 12, 2003 at 14:50:11, Dann Corbit wrote:


>An n-bit SDBM hash scheme would be a good one, I bet.
>Perhaps 2^20 entries (1,048,576) and a simple and operation will finish the
>hash.  (Or you could even have an unsigned:20 type).
>
>The SDBM hash is super simple and yet of high quality.
>http://www.cs.yorku.ca/~oz/hash.html

Thanks for the pointer.
It is byte (8-bit) based. A similar scheme could probably be 32-bit based,
making the calculation much more efficient. For the two 48-bit pawn bitboards
and the 12 bit KK data (the 12 bit would be enough, to also include castling
rights), 4 cycles would be enough, instead of 14 cycles needed for a byte based
approach.

Regards,
Dieter



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