Author: Dave Gomboc
Date: 08:35:58 11/10/03
Go up one level in this thread
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
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