Author: Martin Giepmans
Date: 10:29:38 11/23/02
Go up one level in this thread
On November 23, 2002 at 12:52:21, Omid David Tabibi wrote: >On November 23, 2002 at 11:37:25, Martin Giepmans wrote: > >>On November 23, 2002 at 08:48:36, Omid David Tabibi wrote: >> >>>On November 23, 2002 at 08:45:00, Uri Blass wrote: >>> >>>>On November 23, 2002 at 08:11:37, scott farrell wrote: >>>> >>>>>Just after other people's thoughts. >>>>> >>>>>I think Omid's work overlooked the adapative null move searching many of us do, >>>>>ie. transitioning from r=3 to r=2. >>>>> >>>>>I think adaptive null move tries to GUESS where to use r=2 to reduce the errors >>>>>that R=3 makes. I guess it depends on how often this GUESS is correct, the cost >>>>>of the verification search, and how long it takes the adaptive searching to >>>>>catch the error at the next ply. >>>>> >>>>>Has anyone looked at setting the verification search to reduced depth of 2 >>>>>(rather than 1)? obviously to reduce the cost of the verification search. >>>> >>>>Omid checked it but you also reduce the gain. >>>> >>>>I think that I will look for good rules when to do the verification search so >>>>the cost will be significantly smaller but the gain is going to be the same in >>>>at least 99% of the cases. >>>> >>> >>>I'm currently working on other variations. The initial results are promising. >>> >>>>Uri >> >>I have done some tests with your method at greater depths. >>At depth 12 vrfd R=3 still had an overhead (in terms of treesize) of about >>25% compared to pure R=3. > >Of course verified R=3 will *always* construct a larger tree than standard R=3. >However, starting from a certain depth, it will always construct a smaller tree >than standard R=2. > >Take note, that while verified R=3 constructs a slightly larger tree than >standard R=3, it has a superior tactical strength to even R=2 ! > > >> >>(my engine uses a simple Q-search that shouldn't give problems here) >> >>So the question is if your expectation that the treesize of R=3 and vrfd R=3 >>converge at greater depths (> 11) really holds. >> >>Needs more testing, I think. >> >>Another point: >>I would expect that vrfd R=3 becomes less safe at greater depths. >>The subtrees in which you don't verify nullmove (after the verification) become >>deeper and I see no reason - on logical grounds - why this shouldn't give safety >>problems. >>Even if R=3 and vrfd R=3 converge in terms of treesize, the safety (or rather >>the lack of it) might also converge ... >> > >None will converge. That is what you hope. And hope is a good thing, for sure :) But how do you know? In your article there are no results for depths>11. >However, the deeper you go, the smaller will be the difference in tree size, and the greater the difference in tactical strength. > Again, how do you know? Martin > >>In any case, thanks for sharing. >> >>Martin
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