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Subject: Re: Ultra small pawn hash efficiency

Author: Matthias Gemuh

Date: 09:39:24 11/21/02

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On November 21, 2002 at 11:07:38, Robert Hyatt wrote:

>On November 21, 2002 at 08:26:48, Matthias Gemuh wrote:
>
>>On November 21, 2002 at 08:15:50, Georg v. Zimmermann wrote:
>>
>>>On November 21, 2002 at 07:13:10, Vladimir Medvedev wrote:
>>>
>>>>depth = 9, from initial position:
>>>>
>>>>pawn hash = 1 entry -- 28% successful hits
>>>>2  --  33%
>>>>3  --  37%
>>>>4  --  38%
>>>>5  --  41%
>>>>7  --  43%
>>>>10 --  45%
>>>>100 -- 60%
>>>>...
>>>>65K -- 84%
>>>>
>>>>I was quite surprised with this :)
>>>>Even 1-node pawn "hash" helps a lot!
>>>
>>>Doesnt one get something around 99% with big tables ?
>>
>>
>>
>>With 2x65kB. More is not needed, if only pawns are considered.
>
>
>There are more possible pawn positions than that.  White has 8, black has 8.
>there are
>48 possible squares any of them can be on...  That is a pretty big number.



Some hasty and wrong thinking then, when I implemented my pawn hash.
Maybe I somehow excluded strange positions like all pawns on 2nd and 3rd rows.
I shall check my code and logic later.
I generate keys such that they lie in range 1..2x64kB and use them as index.
I hit 95%..99% in middle game and WAC.

Thanks,
Matthias.

Thanks,
Matthias.



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