Author: Robert Hyatt
Date: 08:04:55 11/21/02
Go up one level in this thread
On November 21, 2002 at 08:34:36, Uri Blass wrote: >1)I do not find in the pseudo code in figure 3 undo null move. > >I assume that it should be before if value>=beta and after value=-search(...) >Am I right? Remember that a null move is not a move. So it is possible that there is nothing to undo. I update the hash signature to avoid a different problem, so I have to undo that as you suggest... > >2)What is the value of the research for tactical strength? >Should it help significantly relative to searching to reduced depth when >value>=beta without research (even when we get value that is less than beta). > The idea is that it is one ply shallower than the normal search, but one-two plies deeper than the null-move search. Another point is that it avoids many zugzwang cases where not making a move fails high, but making a move fails low which rejects the null-move observation completely and avoids the potential zugzwang. > >3)What should be in the research? >I think that only calling search with the original alpha and beta. > A normal search call, yes. although depth is reduced by 1 ply. >My first thought was that I can do it at the end of the search but the problem >is that at this stage I do not know alpha. > >Note that in movei I did not use (!verify||depth>1) because I do not do null >move with depth=1 so this condition always happen. > >Uri
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