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Subject: Re: Bitboard by any simple engine?

Author: James Swafford

Date: 04:17:01 05/30/04

Go up one level in this thread


On May 30, 2004 at 03:36:59, Sune Fischer wrote:

>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.

SEE scores moves, it doesn't sort: do you use (1)bubble sort,
(2)quick sort, (3) no sort (scan for best) .. ?

--
James


>
>-S.



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