Author: Robert Henry Durrett
Date: 13:22:14 06/04/02
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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? Bob D.
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