Author: Robert Hyatt
Date: 19:48:42 11/24/02
Go up one level in this thread
On November 24, 2002 at 12:00:00, Ulrich Tuerke wrote: >On November 24, 2002 at 11:10:17, Robert Hyatt wrote: > >>On November 24, 2002 at 10:08:06, Ulrich Tuerke wrote: >> >>>On November 23, 2002 at 00:57:57, Anthony Cozzie wrote: >>> >>>>The discussion on verified null move pruning has got me thinking about my >>>>qsearch. Right now zappa does simple-stupid qsearch: captures and recaptures, >>>>and I'm thinking about adding some things. If I have a better q-search it may >>>>be possible to move to straight R=3, which would be faster than the current >>>>R=2/3 (Heinz). So I am considering adding: >>>> >>>>1. Pawn Promotions. It would be very easy to add some sort of "generate white >>>>pawn promotions". Usually there would be none, but this could be determined >>>>quickly by a bitboard and (for those of us smart enough to use bitboards . . . . >>>>hehehe) >>>> >>>>2. Check evasion. Right now if one of the captures puts the King in check in >>>>qsearch, zappa just stops. >>>> >>>>3. A Horizon zone. For example, Search() would call horizon() which would call >>>>QSearch(). In the horizon zone, Zappa would also search checks and killer >>>>moves. >>> >>>How about >>>4. Check generation. For example, you could generate checking moves in >>>quiescence provided some conditions are fullfilled (e.g. close enough to >>>horizon, checked king standing risky, ...). >>> >>> >>>> >>>>Secondly, what are people's opinions on SEE versus futility pruning in QSearch? >>>>I was using SEE up until recently, when I did some experiments and decided >>>>Qsearch was working better. Of course, I may just have bugs in my SEE. >>>> >>>>I'll probably try most or all of this stuff anyway, but I'm curious what other >>>>people's views on this are. >>>> >>>>anthony >> >> >>I've mentioned this before, but in Cray Blitz, and some very early crafty >>versions, I had a three-zone search, rather than the current two-zone search. >> >>Zone one was normal. >> >>Zone two was selective and included mainly tactical moves such as checks, >>captures, moves that contain some sort of threat (found by null-move search) >>and so forth. >> >>Zone three was q-search, although in CB and early Crafty I did do check evasion >>if the same side was in check in all q-search plies so that any mate found would >>be forced... In Cray Blitz we also generated checks in certain cases, but not >>nearly as many as we generated in zone two, the "connector" between a normal >>search and the pure quiescence search... > >Oh yes. I remember your article in "Computers, Chess & Cognition" a long time >ago. IIRC, it was the same proceedings, where Goetsch and Campbell had presented >their null move (for the 1st time ?) . > >Uli They published something prior to the 1989 WCCC event. We used their idea there in fact... They did publish something in Schaeffer's book...
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