Author: Gerd Isenberg
Date: 11:31:08 05/06/04
Go up one level in this thread
On May 06, 2004 at 11:58:11, Robert Hyatt wrote: >On May 06, 2004 at 11:38:44, Dan Honeycutt wrote: > >>Yet again I apologize for asking a question which I'm sure has been asked many >>times before, but could someone explain the difference between a fail-hard and a >>fail-soft and how does is affect a PVS search? >> >>I made the guess that, ie, if (score >= beta) if I return score it's a fail-hard >>and if I return beta it's a fail-soft. It would seem that what I return doesn't >>so much matter as what I put in the hash table. If I put in the (possibly) >>higher value of score then I have a higher lower bound and a greater chance for >>a hash cut if this position arises again. >> >>Thanks in advance. >>Dan H. > >That is backward. But you have the right idea. Fail-hard never returns a value >outside the initial alpha/beta window. Fail-soft does. I often confuse this hard/soft definitions too - i have the wrong mnemonic trick. Intuitively i found it harder if i jump outside a window ;-)
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