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Subject: Re: Mirroring a 32bit bitboard

Author: martin fierz

Date: 01:15:34 04/11/02

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On April 10, 2002 at 15:56:54, Alvaro Jose Povoa Cardoso wrote:

>For checkers EGTBs I store only 'black to move entries'.
>For 'white to move' I reverse the board and exchange colors.
>Using 32bit bitboards I need to reverse (mirroring) the board bitboards and the
>exchange the colors.
>
>Thank you all,
>Alvaro Cardoso

hi alvaro,

have you written your own program by now or did you adapt mine? if you are doing
the second, then the answer to your question is "it's irrelevant" - and probably
the answer is the same if you wrote your own program... my generator took 5
weeks on a XP1600+ with 1GB ram to build the 4-4 database (and anything
smaller). once you have this, you will never need to compute it again... another
point is that in spanish checkers, you should be much faster building the db,
because AFAIK kings sweep, and you have lots more captures which take you in
smaller databases much faster than in english checkers, i.e. the number of
passes per db you have to do should be much smaller.

in the meantime, i have compressed my database, and am working on the access
code. believe me: this is the part you have to do right - not the db computation
itself.

aloha
  martin



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