Author: Omid David
Date: 20:42:03 07/07/02
Go up one level in this thread
On July 07, 2002 at 21:43:47, Robert Hyatt wrote: >On July 07, 2002 at 16:47:33, Omid David wrote: > >>On July 07, 2002 at 16:36:57, Robert Hyatt wrote: >> >>>On July 07, 2002 at 11:48:27, Omid David wrote: >>> >>>>On July 06, 2002 at 23:23:28, Robert Hyatt wrote: >>>> >>>>>On July 06, 2002 at 22:29:44, Omid David wrote: >>>>> >>>>>>On July 06, 2002 at 10:20:17, Robert Hyatt wrote: >>>>>> >>>>>>>On July 06, 2002 at 01:07:36, Ricardo Gibert wrote: >>>>>>> >>>>>>>> >>>>>>>>Okay, but so what? >>>>>>>> >>>>>>>>> >>>>>>>>>So perhaps the idea of "forward pruning" is foreign to us as well... >>>>>>>> >>>>>>>>I see no logical difference between deciding which moves are interesting and >>>>>>>>worth looking at and deciding which moves are not interesting and not worth >>>>>>>>looking at. It looks to me like 2 sides of the same coin, so your speculation >>>>>>>>that "perhaps the idea of "forward pruning" is foreign to us as well..." does >>>>>>>>not seem to be of any consequence. >>>>>>>> >>>>>>> >>>>>>>However, that has been _the point_ of this entire thread: Is DB's search >>>>>>>inferior because it does lots of extensions, but no forward pruning. I >>>>>>>simply said "no, the two can be 100% equivalent". >>>>>> >>>>>>Just a quick point: The last winner of WCCC which *didn't* use forward pruning >>>>>>was Deep Thought in 1989. Since then, forward pruning programs won all WCCC >>>>>>championships... >>>>> >>>>> >>>>>In 1992 no "supercomputer" played. In 1995 deep thought had bad luck and lost >>>>>a game it probably wouldn't have lost had it been replayed 20 times. No >>>>>"supercomputer" (those are the programs that likely relied more on extensions >>>>>than on forward pruning due to the hardware horsepower they had) has played >>>>>since 1995... >>>>> >>>>>I'm not sure that means a lot, however. IE I don't think that in 1995 fritz >>>>>was a wild forward pruner either unless you include null move. Then you >>>>>would have to include a bunch of supercomputer programs including Cray Blitz >>>>>as almost all of us used null-move... >>>> >>>>I personally consider null-move pruning a form of forward pruning, at least with >>>>R > 1. I believe Cray Blitz used R = 1 at that time, right? >>> >>> >>>I believe that at that point (1989) everybody was using null-move with R=1. >>>It is certainly a form of forward pruning, by effect. >> >>Yes, and today most programs use at least R=2... The fact is that new ideas in >>null-move pruning didn't cause this change of attitude, just programmers >>accepted taking more risks! > > >I think it is more hardware related. Murray Campbell mentioned R=2 in the >first null-move paper I ever read. He tested with R=1, but mentioned that >R=2 "needs to be tested". I think R=2 at 1980's speeds would absolutely >kill micros. It might even kill some supercomputers. Once the raw depth >with R=2 hits 11-12 plies minimum, the errors begin to disappear and it starts >to play reasonably. But at 5-6-7 plies, forget about it. So using a fixed R=3 seems to be possible in near future with faster hardware, doesn't it?
This page took 0.02 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.