Author: Tony Werten
Date: 16:24:41 01/27/01
Go up one level in this thread
On January 27, 2001 at 19:00:30, Carlos del Cacho wrote: >On January 27, 2001 at 16:43:05, Tony Werten wrote: > >>On January 27, 2001 at 16:34:53, Carlos del Cacho wrote: >> >>>On January 27, 2001 at 14:30:18, Severi Salminen wrote: >>> >>>>Hi! >>>> >>>>I made a few test games between a version of my engine using SEE and another >>>>using just MVV sorting. I played only a few (24) games and time control was >>>>5min/G and in 8 games 1min/G. The result was 12-12! Is this possible, normal, or >>>>do I have a bug? I would have guessed that the SEE version had beat the hell out >>>>of the other but that never happened. It seems that SEE slows things down a lot >>>>and the net result seems to be that it searches equally deep compared to the >>>>other version. Has anyone here measured the true benefit of using SEE? Could you >>>>show me positions in which SEE makes a big difference or could you run self-test >>>>games between two versions of your program? Are there positions where SEE hurts >>>>searching? I really like to know if SEE is worth it? I have a relatively slow >>>>computer (300Mhz Celeron, Crafty running at 80KNPS) so could time control and >>>>overall speed have influence on this? >>>> >>>>Any comments are welcome! >>>> >>>>Severi >>> >>>Just a quick test. Two runs on WAC 5 sec/problem: >>> >>> - SEE pruning in Quiescent Search: 270 >>> - without it: 246 >>> >>>So it is definitely a win for my program (Pepito). >>> >>>The only difference between these builds was commenting out these lines: >>> >>> val = SEE(pos_stack->jug); >>> if (val < 0) >>> continue; >>> >>> val += MARGEN_QUIES + pos_eval; >>> >>> if (val <= alpha) >>> continue; >>> >>>But you should note that I try not to call the SEE function whenever possible. >>>If I can get a cut with pos_eval + mat_gain I give up this capture. Another >>>question is if SEE is profitable in normal search. I also it there but kicking >>>it out would be a bit more difficult so I haven't tried yet :-). At the same >>>time captures are generated I assign them their MVV/LVA scores. Then I try >>>captures with positive scores and when this gets below zero I call SEE for >>>remaining moves. Losing ones are searched after all non captures. I'm not really >>>sure about the gains here so I'll give it a try... >> >>I'm a correct in assuming you don't do checks in qsearch and your MAX_EVAL < 2 >>pawns ? Because in that case SEE is definitly a win ( maybe also if you do some >>checks and max_eval is a bit bigger than 2 pawns ) > >Yes. I don't include checks in quiesce. I rely in check extensions in normal >search. And my evaluation function can only get positional values over 2 pawns >in the endgame so I should disable this there. I think so. Disabeling lazy eval should help you in the endgame. (Or actually: lazy eval should hurt you in the endgame ) ( just an opinion ) Tony > >Carlos > > >> >>Tony >> >>> >>>Greets, >>>Carlos
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