Author: Bas Hamstra
Date: 14:18:03 01/21/02
Go up one level in this thread
On January 21, 2002 at 16:47:09, Antonio Dieguez wrote: >On January 21, 2002 at 16:30:22, Bas Hamstra wrote: > >>On January 21, 2002 at 15:56:59, Antonio Dieguez wrote: >> >>>>It should matter in quiet positions, right? >>> >>>Well, It should matter depending on how often the pv changes, so may be more in >>>unquiet positions. >>> >>>>Well, here is data, opening >>>>position: >>>> >>>>Rootwindow <-inf, inf> takes 2404K nodes >>>>Rootwindow <-50, 50> takes 2420K nodes >>>> >>>>...to complete 10 ply. >>> >>>strange, I don't know the logic there, i would have guessed a bigger >>>difference. please don't be angry but if that is what I would get in amyan >>>regularly I would be sure it has a bug or I made a mistake in the experiment. >> >>It is possible of course, but I don't think so. It just don't seem to buy me a >>lot. As far as I know it has never been proven anyway. Plus (based on only a >>couple of tests) I simply don't see it here. > >but search with alpha+1,beta is better if beta is not infinite. I don't think >that using pvs changes that much, the results of your tests, if have done well, >are counterintuitive. Yes. I am not claiming it is better of course. It just happened in this position. But it is interesting to figure out how this can happen in *any* position. One thing I can think of is that you lose bound info. >>>>Convince me with data :-) Should be no big deal to do this little test for >>>your engine? Difference? Other position is also fine. >>> >>>I'm not using much pvs inside the three as it does not help me, may be other >>>person may do that quicker. >>>Be well... >> >>Do you use straight alphabeta? PVS might be a tiny bit more efficient. At least >>that is what everybody says. But the difference is small IMO. >hyatt says that for him, the difference between alphabeta with aspiration and >pvs is only 10%, for me is near zero. Well that is a number that does not seem unrealistic to me. Only slightly better. On the other hand not having a rootwindow spairs you the trouble of having fail-low's. After which you have no hashmove, *bang*. What's better overall remains a question for me. Best regards, Bas.
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