Author: Robert Hyatt
Date: 05:29:03 06/22/00
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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. > >But it's hard to figure out what checks to do and what you don't need >to do. It's simply hard work, but possible for everyone to do. > >It's hundreds of lines of code in DIEP. > That is hundreds of lines of code I don't have to deal with. And since the entire concept of 'quiescence search' is flawed in a basic way, I want to make that part of my search smaller, _not_ larger. >>I personally don't do them because I don't like the q-search at all. It is >>unreliable, and way too selective to trust. You show me a position where the >>best q-search move is a check (say a capturing check) and I'll show you a >>position where the best response to a capture is _not_ another capture, but >>rather a quiet move that pins or indirectly attacks something. The q-search >>misses way too much. I think it is more profitable to make your basic search >>better by extending in the right places, since it already has no real inherent >>pruning errors other than a lack of depth. I'd like to drive the q-search to >>almost nothing, as that would eliminate many errors.
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