Author: Alvaro Jose Povoa Cardoso
Date: 11:03:08 08/03/01
Go up one level in this thread
On August 02, 2001 at 09:10:38, Vincent Diepeveen wrote: >On August 02, 2001 at 08:46:18, Robert Hyatt wrote: > >>On August 02, 2001 at 04:27:01, Bruce Moreland wrote: >> >>>On August 02, 2001 at 03:54:39, Dann Corbit wrote: >>> >>>>On August 02, 2001 at 03:44:01, Janosch Zwerensky wrote: >>>> >>>>>Hi all, >>>>> >>>>>I read some time ago that Deep Blue wasn't using heuristic game tree pruning >>>>>methods (like, for example, the null-move technique). >>>>>Since null-move was known when DB was around, can anyone here tell why the DB >>>>>team decided not to use it (or wasn't able to do so)? >>>> >>>>Safety. >>>>But don't imagine brute force mini-max. Not like that at all. As a matter of a >>>>fact, beyond 30 seconds, wonderful things might happen. >>> >>>When I started doing computer chess there were people searching (gasp!) nine >>>plies, and some of these people were talking about how the tree is way different >>>when you search that deep. There was talk of tactical sufficiency and lots of >>>other craziness. >>> >>>Now that we can do nine-ply searches in blitz games, a lot of that talk drops by >>>the wayside. >>> >>>I've always wondered about DT/DB and null move. It may be that they had >>>everyone so incredibly supersetted that they didn't need to mess with stuff like >>>this, but I'd think it was pretty incredible if they were still not using null >>>move. >>> >>>Null move is great, and as far as I can tell it works at any tree depth. >>> >>>This is one of the reasons I don't just keel over and die when Bob argues that >>>they are so bloody fast, and therefore they must be godlike. Yes, they are >>>fast, but they don't use the same kind of search. Maybe 98% of that tree is >>>crap, because against a human or a micro program running on a 286, it makes >>>sense to not make pruning mistakes rather than search an extra five plies (all >>>numbers approximate and probably way off). I don't know. There are ways to >>>find out, but they involve being able to test the thing. >>> >>>bruce >> >> >>Just remember, not _everybody_ today is using null-move. Yet their programs >>are still incredibly strong. > >Give example of a strong PC program that's *not* using nullmove or >something that looks amazingly close to it (so close that we can >*call* it a cheaper replacement than nullmove already is). I may be wrong, but I seem to recall that someone here said that Deep Junior 6 does not use nullmove. > >Let's quote a few programs 100% sure use nullmove: > - Crafty > - Darkthought > - Diep > - Fritz > - Gandalf > - Hiarcs > - Lambchop > - Shredder > - SOS > - Tiger > - The King > >Oh well let's use the WMCC participants list 2001: > >DIEP >Ferret >Fritz >Gandalf >GromitChess >IsiChess X >parsos >Pharaon >Rebel >Shredder >SpiderGirl >Tao Yin >Tiger >XiniX > >Only Ed Schroeder says he didn't use nullmove in the past, but >how about his current version? > >The rest is already not making secrets. > >Only some outdated crap is not using nullmove!! > >Best regards, >Vincent
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