Author: Antonio Dieguez
Date: 14:46:13 01/21/02
Go up one level in this thread
On January 21, 2002 at 17:41:54, Bas Hamstra wrote: >On January 21, 2002 at 17:28:11, Antonio Dieguez wrote: > >>On January 21, 2002 at 17:18:03, Bas Hamstra wrote: >> >>>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. >> >>ok but it shouldn't matter much when using a conservative window, except in big >>fail low or fail high. >> >>>>>>>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. >> >>"After wich you have no hashmove" >>you mean the hash moves of positions inside that tree? they don't have to be >>deleted by the fail low... altough yes possibly if the thing is failing low may >>be some of them were not so good but they are there. >> >>best wishes... >>me. > >Suppose you search with <-50, 50> and get a fail low on the root. Now you have >to re-search. And what is the hashtable giving you? A move with score < -50. It >might as well be < -1000 and not a good move to play first. If you do nothing >about it the search might totally crash. That's why Crafty uses "internal >iterative deepening". so you meant at the root? that is bestmove but you told hashmove... ok about internal iterative depending it only hurts a bit in amyan.... what a weird program uh. best regards again... me.
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.