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Subject: Re: Pawn Hashkey Size

Author: David Rasmussen

Date: 14:50:15 12/03/01

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On December 02, 2001 at 23:58:43, Robert Hyatt wrote:

>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.

Are you saying that if I'm seeing collisions, I have a bug, or are you saying
that 300 collisions out of 60.000.000 successful probes is not a problem? If the
latter, then why? How can you be sure?

/David



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