Author: Dave Gomboc
Date: 02:35:12 07/22/00
Go up one level in this thread
On July 22, 2000 at 03:33:52, Ed Schröder wrote: >On July 21, 2000 at 23:00:49, blass uri wrote: > >>On July 21, 2000 at 22:27:45, Robert Hyatt wrote: >> >>>On July 21, 2000 at 19:16:41, Ed Schröder wrote: >>> >>>>On July 21, 2000 at 15:29:26, Robert Hyatt wrote: >>>> >>>>If you don't mind I only answer those points not earlier discussed >>>>(enough) to avoid ending up in endless circles. >>>> >>>> >>>>>>2) DB is no brute force program (as you always have claimed). Quote >>>>>>from the IBM site: >>>>>> >>>>>> "Instead of attempting to conduct an exhaustive "brute force" >>>>>> search into every possible position, Deep Blue selectively >>>>>> chooses distinct paths to follow, eliminating irrelevant searches >>>>>> in the process." >>>>>> >>>>>>I always said this after I had seen the log-files. It beats me how you >>>>>>always have claimed the opposite on such a crucial matter presenting >>>>>>yourself as the spokesman of Hsu even saying things on behalf of Hsu >>>>>>and now being wrong on this crucial matter? >>>>> >>>>>Sorry, but you are wrong and are interpreting that wrong. DB uses _no_ >>>>>forward pruning of any kind, this _direct_ from the DB team. The above is >>>>>referring to their search _extensions_ that probe many lines way more deeply >>>>>than others. If you want to call extensions a form of selective search, that >>>>>is ok. It doesn't meet the definition used in AI literature of course, where >>>>>it means taking a list of moves and discarding some without searching them at >>>>>all. >>>> >>>>The quoted text describes DB as a selective program, no brute force. I >>>>don't see how you can explain it otherwise. The text is crystal clear. >>>> >>>> >>> >>>Why don't you simplyh ask Hsu, or are you afraid you will get an answer >>>you don't want? DB was _always_ brute force. Every document written about >>>DB said this. The paragraph you are quoting is talking about "selective >>>search extensions" which was one of the real innovations from the Deep Thought >>>development (singular extensions, later used by Lang, Kittinger, Moreland, >>>Hyatt, who knows who else). >>> >>>You _know_ they were basically in the same mold as the rest of us. This has >>>_never_ been in doubt. >>> >>>If you do doubt it, just ask the horse's mouth, since you don't want to believe >>>me. >> >>I do not believe to things that seem illogical. >> >>I do not want to believe the 17-19 brute force depth with no pruning of deep >>blue because it sounds too good to be right. > >You are right Uri. Doing 17-19 brute force in the middle game is IMPOSSIBLE. > >Ed Some time ago I referred to a paper authored by Hsu, Campbell, and Hoane(published in 1999) that described it being full-width at the top of the software search, selective near the tips of the software search, and full-width again at the top of the hardware search. I recall that previous DT/DB stuff was full-width the whole way, but this apparently was changed for DB2 -- i.e. I think Bob's info re: "search is entirely full-width" is not correct for the second match vs. GK. I don't have a copy of the paper anymore, but I did fax Ernst Heinz a copy shortly after it came out, so he might have it around still. Dave
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