Author: Bruce Moreland
Date: 13:26:39 03/09/99
Go up one level in this thread
On March 09, 1999 at 16:17:24, Dan Homan wrote: >On March 09, 1999 at 14:34:49, Will Singleton wrote: > >> >>Using PVS, I can't seem to demonstrate a clear benefit to using a small window >>around the root score, as opposed to +-mate. >> >>Using a window of, for example, one-third pawn, if a move fails-high or low, it >>takes fewer nodes to ascertain the move that caused the change, because you >>don't have to find the real score right away. But then you've got to resolve >>the new score, and that will take more nodes since you've got to re-search with >>the relaxed window. >> >>And if, after a fail-high or low, you attempt to delay score resolution until >>the next ply (to avoid the re-search at the same ply), it seems you might have >>the problem of finding a worse move after the fail at the same ply, since you >>don't know the real score yet. This would result in even more nodes being used. >> >>So I don't see much benefit, unless I'm doing something wrong (likely). On a >>normal search, without any fails, I see either more or less nodes (between >>windowing and +-mate), depending on the position. But not really much change. >> >>Any comment would be apppreciated. >> >>Will > >I've gone back and forth on this issue myself. My testing seems to show >that a small window (+,- 1/4 pawn) is slightly (a couple of percent) >faster when measured over a large number of problems than (+,- mate), >but the coding is a bit more complicated. > >I think I'll test this again.... > > - Dan I ran with a +- 32767 window for months and didn't notice. bruce
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