Author: Andrew Dados
Date: 11:27:32 06/23/00
Go up one level in this thread
On June 23, 2000 at 02:06:27, Bruce Moreland wrote: >On June 22, 2000 at 17:38:37, Vincent Diepeveen wrote: > >>On June 22, 2000 at 08:29:03, Robert Hyatt wrote: >> >>>On June 22, 2000 at 07:55:53, Vincent Diepeveen wrote: >>> >>>>On June 21, 2000 at 11:12:23, Robert Hyatt wrote: >>>> >>>>>On June 21, 2000 at 11:03:42, David Rasmussen wrote: >>>>> >>>>>>I find that a lot of the games that my program loses, it loses because it >>>>>>doesn't search checking moves in qsearch. >>>>>>Anyway, how do people do that most effectively? I would like not to generate all >>>>>>moves in the qsearch (just the captures), but then I will miss the noncapturing >>>>>>checks. >>>>> >>>>> >>>>>I did them in Cray Blitz, and in early versions of Crafty. But I haven't >>>>>done checks in the q-search since just prior to the Jakarta WMCCC event. >>>>> >>>>>You can control them to an extent... ie when you get to the q-search, you >>>>>can consider a check. But if you look at a capture at the first ply or 2, >>>>>then there is little point in doing checks deeper in the q-search because the >>>>>'stand pat' will allow you to avoid the checks totally, earlier in the >>>>>tree. >>>> >>>>76% of all checks give a cutoff in DIEP in qsearch >>>>on average a check improves score with 2.9 pawns >>> >>>That is fine. But if 76% of checks are giving cutoffs, you have a problem >>>somewhere else, because _most_ cutoffs should be produced by captures, not by >>>checks. >> >>That's pretty hard to measure in a realtime program and i disagree here. >>If you're in check, then you don't need to evaluate and have limited choice, >>so the number of nodes you cycles you waste when being in check is >>quite limited. >> >>3 out of 4 checks giving a cutoff in a position which wasn't a cut node >>without trying the check (otherwise beta pruning) is pretty good i think. >> >>I'm sure most don't get such a good cut rate. > >I don't see how this makes any sense. Why would a check give a cutoff unless >it's a mate, a capture, or the subject of an eval function bonus? > >bruce [D]4k3/8/8/8/r7/8/6Q1/4K3 w - - We're in qsearch here. Qxc6+ Kxx QxR will give a cutoff, no? -Andrew-
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