Author: Dave Gomboc
Date: 11:48:43 08/18/00
Go up one level in this thread
On August 18, 2000 at 13:53:16, J. Wesley Cleveland wrote: >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. Yes, the technique relies upon the information from the deeper searches being present and used to perform cutoffs at shallower searches. Dave
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.