Computer Chess Club Archives




Subject: Re: A story about NPS

Author: Carlos del Cacho

Date: 00:11:08 01/27/01

Go up one level in this thread

On January 26, 2001 at 12:49:15, Severi Salminen wrote:

>>What you say is extremely to the point. I have had similar results with Chess
>>Tiger. I can easily increase my NPS and beat everything else on NPS (on PC, I
>>mean), but my program would be significantly weaker.
>>The kind of NPS increase I'm talking about is not by removing chess knowledge. I
>>can keep exactly the same evaluation, and by changing several things in the
>>search (removing pruning algorithms), I can increase my NPS dramatically. But
>>the program will be weaker, even if it is 5x faster in NPS.
>Yes. What made me worry is that when I removed SEE from my engine and played
>(just a couple of) games between a version with SEE there were no differences in
>tactical play. Could it really be that SEE slows things so much down that the
>benefit isn't really significant? I hope this is not the case because I spent _a
>lot_ time adding those xray attacks in SEE...
>In Qsearch I stop searching more moves in that node when
>eval(node)+move[i].see_score+PAWN_VALUE drops below alpha (they are sorted).
>Could this be even more selective? Maybe the PAWN_VALUE could be 0? Have to
>try... Maybe it would make things brighter for SEE. (I might remember something
>wrong as I don't have access to source code right now.)

I prune in Quiesce if the above condition meets or SEE value is below zero. That
should speed you up a bit.


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