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Subject: Re: Bitboard VS array board ,speed difference in movegen()

Author: Severi Salminen

Date: 03:50:17 03/01/01

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>Actually,my current program is checkers one. In former version,
>I use single array board representation. After I read Amy source
>code,I understand how bitboard works. I heard many people said
>bitboard can generate move faster in chess. In checkers,
>some facts are no nullmove,no killers,no PVS ,no SEE etc..and
>very simple eval() and  plain AB function with hash table.
>So,I think if I can improve movegen() speed,my program
>will be stronger. Then, the project start ,I wrote a new checkers
>program based on bitboard ,modified from Amy. The result was
>quite dissapointed it's slower. You may look at what Dr.Hyatt
>commented. Amy bitboard always updates attack_to,attack_fr
>informations in (un)makemove()s.

So what do you do in movegen()? What information you need there that you
generate in makemove(). I use rotated bitboards and I don't generate anything in
makemove() - I only update necessary bitboards. You really should try other
forms of bitboards. My experience is that they really are fast if implemented
"correctly".

Severi



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