Author: Vincent Diepeveen
Date: 06:10:38 08/02/01
Go up one level in this thread
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). 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
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.