Author: Dave Gomboc
Date: 09:01:59 11/09/03
Go up one level in this thread
On November 08, 2003 at 12:43:29, Robert Hyatt wrote: >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... Replied in other thread. Dave
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