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Subject: Re: Why using Zobrist keys for Pawn Hasing?

Author: Gerd Isenberg

Date: 02:45:12 12/06/01

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in my current implementation i use the difference of the black and white pawn
BitBoards mod nEntries (which i learned here is not so smart) for indexing the
pawn table - with nEntries is a prime > 50000. The entries are quite large with
a lot of BitBoards in it for pawn properties such as backward, isolated, open
and passed. They also include the original pawn BitBoards for black and white
for verification. I use a replacement sheme, that checks up to four consecutive
entries - the one with the lowest ProbeCount will replaced.
There are no ep- neither side to move information in my pawn hash table.

The hit rate seems to be OK 96%-99.9% - but anyway i should redesign the whole
thing.

Gerd



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