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Subject: Re: One mate to solve...(speed of pn^2)

Author: Angrim

Date: 12:23:46 07/02/01

Go up one level in this thread


On July 01, 2001 at 22:02:24, leonid wrote:

>On July 01, 2001 at 21:14:32, Angrim wrote:
>
>>On July 01, 2001 at 07:48:43, leonid wrote:
>>
>>>Hi!
>>>
>>>I see that your program take well those positions. This last one was slow even
>>>for my solver.
>>>
>>>>proved that move f3xh5 wins, 12 turns
>>>
>>>I am not sure what is "12 turns". Twelve moves deep?
>>
>>24 ply, this is the length of the win it found, which is usually not
>>the shortest possible.
>>
>>>
>>>>PN2:17137399 evals, 368084 expands, 148.10 seconds
>>>
>>>Yes, and still what is everage NPS for your program since we have almost
>>>identical hardware? I am not sure how to read "evals" and "expands". Mine is
>>>Celeron 600Mhz.
>>>
>>
>>evals is the number of calls to the leaf node evaluator.
>>expands is the number of leaf nodes which have been expanded to
>>become internal nodes.
>>an expansion of a node consists of generating and evaluating all
>>of the positions which can be reached by a legal move from that node.
>>
>>
>>>I don't know exactly NPS (node/per/second) for this position for shortest move,
>>>since mine solved it by selective and went by brute force only as far as to be
>>>sure how big is shortest move. For selective, for shortest mate, NPS was 697k
>>>and for brute force (just one move below the last) was 93k. My program don't use
>>>hash, this must make mine NPS somewhat higher that it should be.
>>>
>>>If I forget your "expand", your average is 115k. Something that still look like
>>>we have close NPS numbers.
>>>
>>>Leonid.
>>>
>>
>>my nps is quite low for this, because my check handling code is just a
>>quick kludge to my usual movegen(check does not exist in suicide chess)
>>If I was useing the movegen/makemove from crafty, I would expect
>>results about 10x as fast.
>
>Strange! I could expect NPS for Crafty for this position to be around 400k and
>maximum up to 500K. If your numbers can go twice as fast, it could be the second
>surprise that I saw with NPS for mates. First was when I found that Rebel have
>higher NPS for brute force search that for selective, when it look for mate. I
>never, ever could expected this!
>
>Leonid.

crafty does a lot of stuff that my program doesn't, I seem to recall
Bob saying that less than 20% of crafties time is spent
on movegen/makemove,  while about 90-95% of my programs time is spent
on that.  The eval I use for pn^2 is very trivial, just an estimate
of the number of legal moves at the leaf node.

Angrim



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