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Subject: Re: depthfirst versus depthlimited

Author: Robert Hyatt

Date: 19:59:15 05/19/04

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On May 19, 2004 at 22:28:50, Vincent Diepeveen wrote:

>main() {
>  search(10); // search 10 ply depthfirst
>
>  for i = 1 to 10 // depth limited 1..10 ply search
>    search(i);
>}
>
>search(int depth) {
>  if depth == 0
>    then return eval();
>  else for all moves
>    search(depth-1);
>}
>
>Robert Morgan Hyatt doesn't seem to understand this in his thesis.


Find any good ai book.  Look up "depth first search".  minimax and alpha/beta
are examples.  The idea is that the memory space requirement for depth-first is
O(d) while the memory space requirement for breadth-first (the _only_
alternative) is O(w^d).

depth-first search

(algorithm)

Definition: (1) Any search algorithm which considers outgoing edges of a vertex
before any neighbors of the vertex, that is, outgoing edges of the vertex's
predecessor in the search. Extremes are searched first. This is easily
implemented with recursion. (2) An algorithm which marks all vertices in a
directed graph in the order they are discovered and finished, partitioning the
graph into a forest.

Also known as DFS.

See also breadth-first search, best-first search.

Note: [CLR90, pages 477-485]

Author: PEB

Or go here:

http://www.cs.mcgill.ca/~cs251/OldCourses/1997/topic26/#dfs
http://www2.toki.or.id/book/AlgDesignManual/BOOK/BOOK2/NODE65.HTM


I showed this to a faculty member that teaches AI at another University.  He
responded "is this guy a clown, an idiot, or is he really that stupid?"  I think
that says it all.

So it isn't "Robert Morgan Hyatt" that doesn't know what he is talking about.
You need to look in the mirror.  Once again you are _dead_ busted here.  minimax
and alpha-beta do _exactly_ as the above definition says.  Just do a google
search on depth-first search, read, and stop looking like a fool.

And by all means _stop_ making up false definitions to suit your own agenda.
You can't usurp the meaning of well-known AI terms and re-define them to mean
something you choose.

Yet one more big lie.  When will you grow up and stop?

lookin' even better, Vincent...



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