Author: J. Wesley Cleveland
Date: 10:53:16 08/18/00
Go up one level in this thread
On August 18, 2000 at 09:23:38, Robert Hyatt wrote: >On August 17, 2000 at 18:05:41, Gian-Carlo Pascutto wrote: > >>On August 17, 2000 at 14:43:08, J. Wesley Cleveland wrote: >> >>>When you have a fail-low in a deep search where the value drops significantly, >>>finding an alternate move can take a very long time. This is largely because >the >>>values in the hash table are largely useless, so in effect we are researching >>>the entire tree. It seems to me one should use iterative deepening, and start >>>from ply 1 again. >> >>This technique has been described by Schaeffer a long time ago... >> >>(Obvious question: Why is nearly no-one doing it?) >> >>-- >>GCP > > >I'm not sure what you mean by described a long time ago. But there is a big >problem. If you start over at 1 ply, you don't get the fail low score. You >find (again) the _wrong_ move, until you get deep enough. When there is a big >score swing between two iterations, you take your lumps. There is no way to >cheat alpha/beta there. You should get the fail low score, since it is in the hash table. They should stay there as they are analyzed to a greater depth than you are likely to get to.
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