Author: Christophe Theron
Date: 20:48:36 04/09/04
Go up one level in this thread
On April 09, 2004 at 16:51:34, Anthony Cozzie wrote:
>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
Absolutely, and I think that computing attack tables at every node is
inefficient, and I do not do it. Some say bitboards can do that quickly, but I
have not use for it.
Not sure if you have read my post correctly (or maybe I did a mistake?).
Christophe
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