Author: David Rasmussen
Date: 11:27:34 01/21/02
Go up one level in this thread
On January 21, 2002 at 10:41:39, Robert Hyatt wrote: > >You have to do two things: > >1. If you get a fail high at the root on a zero-width window (any move after >the first move should be searched with a zero-width window) you can't trust it >unless you re-search it with a bigger beta bound and make _sure_ that it doesn't >then fail low. Such fail-high (zero window) fail-low (non-zero window) is an >artifact of null-move and if you play such a fail high move even if it fails low >on the re-search, you will die... > If you mean, do I count value >= alpha+1 from zero-window search as a fail high, then no. In that case, I research with the original alpha;beta window. Isn't that ok? >2. If you get a fail high at the root on the zero-width window, and when you >re-search you get another fail high on the original aspiration window, or you >get a true score, then you can trust it. > That's what I'm doing now, I think. >Case 1 is the killer although it doesn't happen every move, once in a game >is more than enough. I'm sure. But when I posted, I was really talking about the case where you search with an aspiration window, and then you get a fail high with value v. You search with a new aspiration windows (in my case [v;MATE]), but then the search turns out to find nothing. The fail high was false. How do I avoid that? /David
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