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Subject: Re: sliding attacks in three #define

Author: Anthony Cozzie

Date: 13:51:34 04/09/04

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On April 09, 2004 at 15:26:34, Christophe Theron wrote:

>On April 09, 2004 at 14:27:48, Sune Fischer wrote:
>
>>
>>>Clearly, nothing beats the ugliness of bitboards.
>>
>>This may not be the best example to judge by.
>>
>>-S.
>>>    Christophe
>
>
>
>In the contrary, I think it's fairly typical of bitboard code.
>
>Elegance is supposed to be the strong point of bitboards.
>
>The only thing I find elegant is the pseudo-great starting idea "64 squares <->
>64 bits".
>
>Passed this point everything becomes unreadable and ugly.
>
>I also see it often used to pre-compute attack tables and such, which is in my
>opinion contrary to one of the most important things I have learned in computer
>chess: do not compute anything in advance if you are not certain that you will
>use it. This is not an intrinsic problem of bitboards, it's just that use of
>bitboards often go along with this misuse of computing resources, is it just by
>chance?
>
>Bitboards are a great tool allowing you to compute very complex things in a
>blink. The problem is that in a chess program you rarely need to do these
>complex computations if you know what you are doing, and so you end up with ugly
>and unreadable code and waste of resources (in particular of L1 and L2 caches).
>
>That being said, I do not want to be too harsh: it is probably possible to write
>a top-level chess program using bitboards, a program that would be not very far
>behind the programs using more portable approaches like 0x88 and derivatives.
>
>Somebody will write one some day.
>
>
>
>    Christophe (setting up a shield for the upcoming flame)

Correct me if I am wrong, but aren't attack tables the exact opposite of your
"do not compute anything in advance" strategy?

anthony



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