Author: Bruce Moreland
Date: 23:06:27 06/22/00
Go up one level in this thread
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
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