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

Author: Dann Corbit

Date: 14:28:10 06/04/02

Go up one level in this thread


On June 04, 2002 at 16:36:30, Dann Corbit wrote:

>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

Here is a nice tutorial on alternative board representations:
http://www.ics.uci.edu/~eppstein/180a/970408.html

Also, to understand bitboards, James Swafford's tutorial is excellent.
Tragically, it no longer seems to be online.




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