Author: Dave Gomboc
Date: 08:39:07 11/10/03
Go up one level in this thread
On November 10, 2003 at 11:35:58, Dave Gomboc wrote: >On November 08, 2003 at 11:08:41, Robert Hyatt wrote: > >>On November 07, 2003 at 14:14:08, Dave Gomboc wrote: >> >>>On November 06, 2003 at 22:31:49, Robert Hyatt wrote: >>> >>>>On November 06, 2003 at 20:43:58, Dave Gomboc wrote: >>>> >>>>>On November 06, 2003 at 19:46:29, Robert Hyatt wrote: >>>>> >>>>>>On November 06, 2003 at 11:22:54, Dave Gomboc wrote: >>>>>> >>>>>>>On November 06, 2003 at 09:47:32, Robert Hyatt wrote: >>>>>>> >>>>>>>>On November 06, 2003 at 08:33:49, Gian-Carlo Pascutto wrote: >>>>>>>> >>>>>>>>>On November 06, 2003 at 05:45:53, Renze Steenhuisen wrote: >>>>>>>>> >>>>>>>>>>Depth-First Algorithms: >>>>>>>>>> AlphaBeta (Fail-hard, Fail-Soft) >>>>>>>>>> MTD(f) >>>>>>>>>> >>>>>>>>>>Best-First Algorithms: >>>>>>>>>> SSS* >>>>>>>>> >>>>>>>>>The distinction between the three (and best-first and depth-first) >>>>>>>>>is very hazy, read "Research re: search and research" by Aske Plaat. >>>>>>>>> >>>>>>>>>-- >>>>>>>>>GCP >>>>>>>> >>>>>>>> >>>>>>>>Eh? The distinction is _huge_. >>>>>>>> >>>>>>>>One searches the tree in one direction and requires very little memory. The >>>>>>>>other searches the tree in another direction and requires huge memory. >>>>>>>> >>>>>>>>I'm not sure how you could say that the distinction is very hazy. They >>>>>>>>are as different as night and day... >>>>>>> >>>>>>>However, MTD(infinity) is equivalent to (searches exactly the same tree as) SSS. >>>>>> >>>>>> >>>>>>That's fine. A best-first (breadth-first) search can search _exactly_ >>>>>>the same tree as a minimax (depth-first) search also. Doesn't mean a >>>>>>thing about how similar the two approaches are, however... >>>>>> >>>>>>However, the trees are grown differently. I don't think any book I >>>>>>know of uses the actual search space as a way to define a search >>>>>>strategy... >>>>>> >>>>>> >>>>>>> >>>>>>>http://www.cs.ualberta.ca/~jonathan/Grad/plaat.phd.ps >>>>>>> >>>>>>>Dave >>>>> >>>>>Fine, but the point is that in this particular case, they are not as different >>>>>as night and day. :-) >>>>> >>>>>Dave >>>> >>>>They are different in the base algorithm. They are different in their >>>>memory requirements. They are different in the order in which they search >>>>the tree. They are different in how hashing may (or may not) work. >>> >>>They are *NOT* different in the order in which they search the tree. The >>>traversal order is identical. >>> >>>Dave >> >>Sorry but that is _wrong_. It might be true for _one_ example. But >>the topic was the two classes of search, best-first and breadth-first. >>They do _not_ in general, search the trees in the same order. >> >>By their very definition. >> >>Otherwise there would be no breadth-first or depth-first discussions >>in search theory. > >No, the topic was not about best-first and depth-first, it was about the >specific search algorithms GCP mentioned. > >Dave http://www.talkchess.com/forums/1/message.html?325994 Hmm, looks like GCP made reference to specific algorithms, but also general ones in parentheses. I was focussing on the specific ones, I guess you focused on the general ones. :-) Dave
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