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Subject: Re: Pawn Hashkey Size

Author: Robert Hyatt

Date: 20:58:43 12/02/01

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On December 02, 2001 at 22:38:30, David Rasmussen wrote:

>Many people use 32-bit pawn hashkeys. But I've found that 32 bits is not enough
>to avoid collisions. 64-bit seems to be enough, and maybe less could do the job.
>Why do people use 32-bit keys, when it screws up evaluation this way?
>
>/David


32 is ok for pawns.  To see why, figure out how many _different_ positions
there are with only pawns on the board.  The number is not as large as you
might think, which makes collisions unlikely so long as you _only_ hash pawn
positions.



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