Author: Will Singleton
Date: 23:31:23 10/22/99
Go up one level in this thread
On October 23, 1999 at 01:37:47, Christophe Theron wrote: >On October 22, 1999 at 13:08:44, Robert Hyatt wrote: > >>On October 21, 1999 at 15:55:21, Jeremiah Penery wrote: >> >>>On October 21, 1999 at 12:54:47, Christophe Theron wrote: >>> >>>> >>>>But no program of today do brute force. All the good programs are highly >>>>selective. >>>> >>>>If you are not talking about "true brute force" (simple-alpha beta + QSearch) I >>>>don't know what you mean. Everything else is selective. >>> >>>We must be using different definitions. I don't consider the use of null-move, >>>for example, a selective search. >> >> >> >>A word of caution. "selective search" has a precise definition in the CS >>literature, dating all the way back to Shannon's "How to program a computer >>to play chess" in the 1950's. >> I believe it was 1947-48, but I don't have my ICCAJ here... my Dad and Claude used to play a lot in NY around that time. >>Selective search means, very explicitly, to generate all moves at a node in >>the tree, and then to dismiss some of those a priori without any searching of >>any kind. This is also called 'forward pruning'. >> >>The idea of selective extensions was mentioned by Shannon, in the context of >>what he called a "variable depth search" which is exactly what all of our >>extensions and null-move reductions actually accomplish. >> >>I personally don't call a "null-move search" a "selective search" because it >>is an incorrect term of a previously established term. Any more than I would >>self-define the term "ampere" to mean resistance, rather than using the more >>accepted "Ohm". I don't know of anyone doing what I would call purely >>selective search, although our q-search is a perfect example, since we toss >>out some moves with no searching of any kind, while keeping others and searching >>them deeper, all in a pretty arbitrary way. >> >>It makes more sense to keep a common vocabulary when we discuss things so that >>every post doesn't require a personalized "glossary of terms" so that we can >>communicate. :) > > >You are right. It is indeed better that we all use the same vocabulary (and the >idea of a glossary in the "Computer Chess Resource Center" pops up again). > >But in this case, how can we call the kind of "selectivity" we get from, for >example, a null move search? > >Are we going to call this "variable depth search"? It's pretty misleading I >think. > >It is true that we would need some discussion about these terms. The terms >"selectivity" and "full width" are often misunderstood. > >A suggestion, the null move selection could be put in the category of "dynamic >selectivity" (or dynamic pruning) instead of simply "selectivity", to emphasize >on the fact that selection is decided by a search? > >What do all interested readers think? > > > Christophe I do think it's interesting how the language has evolved. I'm not so sure that we ought to be bound by what was originally intended by a particular term. Selectivity, for example, used to mean something other than what it does today; no one implements his program in the old sense of the word. Same goes with razoring, cut, and others. I don't know whether it's possible to get folks to agree on these definitions, since the literature itself presents conflicts. It would be a noble experiment to try to define the terms, however, and perhaps useful for many programmers here. Will
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