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Subject: Re: The need to unmake move

Author: Sune Fischer

Date: 17:06:33 08/20/03

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On August 20, 2003 at 19:51:15, Christophe Theron wrote:

>>Actually I think you are doing the same as Crafty, Crafty is using a mix of
>>copying and undoing as well.
>>The expensive stuff, hash key and rotated boards are copied back.
>>The piece bitboards don't all need accessing, perhaps just 1 or 2 out of ~20, so
>>for this undoing is faster.
>>
>>-S.
>
>
>
>Oh well... Last time I glanced at Crafty I think it was version 9.2 or
>something... :)
>
>
>
>    Christophe

Well looking at it again I believe I was wrong, looks like Crafty does indeed
unmake the rotated boards!? (not the hash keys though).

That has to be a computational overhead, it must be for cache efficiency then.

But even in a 10 ply search this would not require more than 4*8*10=320 bytes.

-S.



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