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Subject: Re: Bitboard by any simple engine?

Author: Sune Fischer

Date: 00:36:59 05/30/04

Go up one level in this thread


On May 29, 2004 at 22:53:38, James Swafford wrote:

>On May 29, 2004 at 16:09:22, Sune Fischer wrote:
>
>>On May 29, 2004 at 14:41:28, Anthony Cozzie wrote:
>>
>>>On May 29, 2004 at 14:26:55, Russell Reagan wrote:
>>>
>>>>On May 29, 2004 at 04:24:18, Tony Werten wrote:
>>>>
>>>>>Yes, you would have to hop to nextsquare to see how it would go from there. Now
>>>>>you only have to look what square we are talking about, and if !nil, you will
>>>>>always know that the nextsquare will be given at *sq++
>>>>>
>>>>>So you basicly made "nextsq" and "location of nextsq" independant of each other,
>>>>>thereby making it independant of board representation and making it more
>>>>>efficient since you will be traveling through the array in a row, rather than
>>>>>randomly accesed.
>>>>
>>>>Would this be any faster than a traditional array based move generator? As far
>>>>as I can tell, the array based movegen will iterate over an array, while the
>>>>move table approach loops over a linked list (effectively). Looping over an
>>>>array will almost always be at least as fast as looping through a linked list,
>>>>right? Plus the move table approach uses more memory to accomplish the same
>>>>thing. You may get some other advantages from a move table approach, but with
>>>>regard to speed, the move table approach doesn't seem like it would be the
>>>>fastest.
>>>
>>>The magic of Vincent's generator is that there are almost no branches and
>>>relatively little memory.  The two biggest wastes of time in a modern deeply
>>>pipelined superscalar processor are branch mispredictions and cache misses.
>>>
>>>anthony
>>
>>I really don't understand all the hype about a generator.
>>I just had a look at a profile, mine spends something like 5% generating moves.
>>That's hardly worth even looking at to optimize.
>>
>>It might be due to its incremental design that it's so fast though ;)
>>
>>Sorting the moves however, now that takes time.
>
>What type of sort do you use?  How often do you sort your
>move list(s)?

I use SEE for the most part, expensive but seems to be well worth it.

-S.



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