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Subject: Re: Algorithms vs. knowledge - What to do next? [correction]

Author: Dann Corbit

Date: 13:36:30 06/04/02

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On June 04, 2002 at 16:22:17, Robert Henry Durrett wrote:

>On June 04, 2002 at 16:20:05, Dann Corbit wrote:
>
>>On June 04, 2002 at 16:14:07, Robert Henry Durrett wrote:
>>[snip]
>>>I was thinking about the use [somehow] of chess knowledge to evaluate the root
>>>node, but without using any search to accomplish this evaluation.
>>
>>If you have no search at all, this approach will fail.  Guaranteed.
>>
>>>This appears
>>>to have been incorrect.  It now looks like you are still relying on examination
>>>of possible lines emminating from the position, in addition to anything else you
>>>may be doing, to evaluate the root node BEFORE selecting the "children."
>>>
>>>Is this closer to the truth?
>>
>>Here is what happens:
>>
>>The root node's children get examined.  The very best looking one becomes the pm
>>(predicted move) which is the first thing in the pv.  That node gets examined
>>very carefully.  All the other nodes get a "zero window search" (which is
>>actually one unit wide).  These searches happen very quickly most of the time.
>>If your evaluation is pretty good, the pm guess will usually be right (90% or
>>better).  Some of the worst moves will get the fat trimmed off with null-move
>>pruning.  They won't be searched as deeply.  You don't have any choice about
>>selecting the children.  The children are each and every legal move from each
>>and every node in the tree.  They don't all get searched at the same depth.
>>Extensions will lengthen some paths and pruning will shorten some others.
>>
>>Have you seen Bruce Morland's or Colin Frayn's tutorials?  They are very good at
>>explaining how computer chess searching works.
>
>No, but it sounds like I really need them!  Where to find?

Bruce:
http://www.seanet.com/~brucemo/topics/topics.htm

Colin:
http://www.ast.cam.ac.uk/~cmf/chess/theory.html



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