Author: Robert Hyatt
Date: 09:43:29 11/08/03
Go up one level in this thread
On November 07, 2003 at 14:16:16, Dave Gomboc wrote: >On November 06, 2003 at 22:42:14, Robert Hyatt wrote: > >>On November 06, 2003 at 22:33:04, Robert Hyatt wrote: >> >>>On November 06, 2003 at 20:45:57, Dave Gomboc wrote: >>> >>>>On November 06, 2003 at 19:50:09, Robert Hyatt wrote: >>>> >>>>>On November 06, 2003 at 11:23:36, Dave Gomboc wrote: >>>>> >>>>>>On November 06, 2003 at 09:49:33, Robert Hyatt wrote: >>>>>> >>>>>>>On November 06, 2003 at 09:33:28, Renze Steenhuisen 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. >>>>>>>> >>>>>>>>Done that already, but as Aske stated: they search the same nodes, but in a >>>>>>>>different order. >>>>>>>> >>>>>>>>MTD(f) and the others are still DF algorithms, the second list works differently >>>>>>>>(i.e., the order in which the nodes are expanded is different). >>>>>>>> >>>>>>>>Or am I talking rubish? >>>>>>>> >>>>>>>>Renze >>>>>>>> >>>>>>>>PS: Am I missing algorithms (either important or not)? >>>>>>>>PS2: Are Scout and NegaScout equal? >>>>>>> >>>>>>> >>>>>>>They are just variations on the same idea. All fall under the umbrella >>>>>>>of alpha/beta depth-first search... (this is in response to your question >>>>>>>PS2). >>>>>>> >>>>>>>depth-first and breadth-first (best-first is one example of the latter) >>>>>>>are totally unrelated other than the fact they both search a tree. >>>>>> >>>>>>Well, no. Read Plaat's thesis. >>>>>> >>>>>>Dave >>>>> >>>>> >>>>>I have read it. It does _not_ say the two are equivalent in any shape >>>>>or form, except for the actual tree searched in certain circumstances. >>>>>Depth-first and breadth-first are completely different approaches to >>>>>growing a tree, even if on some occasions they grow the _same_ tree. >>>> >>>>In this particular case, the algorithms search the same tree. Therefore, I >>>>think it's reasonable to claim they are they are equivalent in some shape or >>>>form -- not in all shapes and all forms, but at list with respect to the nodes >>>>searched and the order in which they are searched. :-) >>>> >>>>Dave >>> >>> >>>I don't believe that last is correct. IE with respect to order. Particularly >>>comparing members of the breadth-first family to the depth-first family and >>>not just picking one specific algorithm from each. >> >> >>BTW, I hope you don't try to convince me all sort algorithms are >>equivalent, just because they take the same list and produce the >>same final result. :) > >Well, what is correct is that the node expansions are done in the same order. > >Dave Again, what two algorithms specifically are you comparing? Best first and depth-first _never_ expand the nodes in the same order, except for trees where each side has only one legal move at every position...
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