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Subject: Re: Bitboards verses Offsets ?

Author: Uri Blass

Date: 07:54:47 10/17/04

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On October 17, 2004 at 10:18:52, Stuart Cracraft wrote:

>On October 16, 2004 at 22:31:45, TEERAPONG TOVIRAT wrote:
>
>>On October 16, 2004 at 10:58:17, Ron Peterson wrote:
>>
>>>     I have seen some messeages about the use of bitboards for move generation.
>>>I use a offset approch for my move generator and I am pleased with the speed.  I
>>>have enclosed a copy of my "gen_white_knight" code.
>>>     My question is what type of speed increase wuold you expect to get in a
>>>move generator using bitboard?  50%?  100%?
>>
>>Hi,
>>
>>I think bitboards generate move faster especially capture moves. But it's slower
>>in makemove() and unmakemove() because it has to update a lot of data.
>>However, you can do a lot of tricks with bitboards in eval().  So,if you want to
>>compare the two methods, you 've to compare the performance not only speed of
>>movegen().
>>
>>Regards,
>>Teerapong
>
>Movegen is not the issue with bitboards.
>In fact, it is a drawback. Much harder to implement
>movegen with bitboards than with 0x88 or mailbox.
>
>The joy is in bitboard eval-ing.
>
>You should make a hybrid program at first using
>mailbox or 0x88 movegen, regular incheck/attack
>routines, and bitboards for movegen.
>
>Later, when you have more time or want bigger
>challenges, convert to bitboarding using examples
>like GNU Chess and Crafty.
>
>I think the next challenge above that is to do
>what Slate and Atkin did and that is to maintain
>incremental attack tables that are updated after
>each makemove and unmakemove.
>
>Stuart

I already have attack tables that are updated incrementally but my move
generator is not based on bitboard or on 0x88 and I simply use 0-63 as the
squares.

info that is array of 64 integers tells me information about squares(for example
info[11] gives information about d2) and I have also piece list for every type
of piece.

Uri



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