Author: Robert Hyatt
Date: 17:58:56 09/12/99
Go up one level in this thread
On September 12, 1999 at 16:58:52, Alessandro Damiani wrote: >On September 12, 1999 at 10:17:42, Robert Hyatt wrote: > >>On September 12, 1999 at 06:38:23, Alessandro Damiani wrote: >> >>>On September 11, 1999 at 22:25:24, Robert Hyatt wrote: >>> >>>>On September 11, 1999 at 17:48:55, Alessandro Damiani wrote: >>>> >>>>>On September 11, 1999 at 15:59:19, Ed Schröder wrote: >>>>> >>>>>>On September 11, 1999 at 15:36:18, Robert Hyatt wrote: >>>>>> >>>>>>>OK... then we are 'in sync' here it seems.. >>>>>>> >>>>>>>As far as PVS, the main advantage is that since almost everything is searched >>>>>>>with a null-window, it saves nodes, _IF_ you do well at move ordering (I have >>>>>>>no doubt that you do well so PVS might be a win for you too)... >>>>>>> >>>>>>>It reduced my trees by 10% and loses nothing at all... unless you screw >>>>>>>up move ordering, then it can make the tree bigger as you first search with >>>>>>>a null window, then you have to re-search with the normal window... >>>>>> >>>>>>Thus, PVS is aspiration search with a null-window? Is that all there is? >>>>>> >>>>>>Ed >>>>> >>>>>I think there is problem with the combination null-window and forward pruning: >>>>>forward pruning is not perfect. So there are more wrong cut-offs with PVS than >>>>>without. This could affect positional play. >>>>> >>>>>Alessandro >>>> >>>> >>>>I don't do forward-pruning at all. Other than the sort of similar idea that >>>>comes out of null-move search with R=2... >>> >>>But null-move is not perfect, too. So there are wrong cut-offs, mainly after >>>quiet moves. >>> >>>Alessandro >> >> >>I would _never_ argue with that. :) >> >>It _definitely_ produces problems in the right kinds of positions. It sort of >>reminds me of banging your head against a brick wall for several minutes. The >>only reason you would do that is because it feels _so good_ when you stop. Null >>move is sort of like that... >> >>:) > >What I mean is that you use R=2 and not R=1. There is a difference in accuracy. > >Alessandro yes there is.. and I am actually not using R=2 (for the last year or so in fact.) I use R=3 near the root, R=2 near the leaf positions. And yes, this has an accuracy issue. It also has a speed issue, and head-to-head testing says that R=2 will beat R=1 by a statistically significant margin.
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