Author: Vincent Diepeveen
Date: 20:18:03 01/26/01
Go up one level in this thread
On January 26, 2001 at 01:52:48, David Rasmussen wrote: >On January 25, 2001 at 19:05:12, Robert Hyatt wrote: > > >>Think about it differently. IE at ply=N, I play a move and I am >>about to do a normal search to depth=X to see how this move works. >>But first, I assume my opponent does nothing, and I then do a much >>shallower search with me to move again. If this is bad for me, there >>is no need for me to search this move to the full depth, I can get away >>with searching it to the shallower depth, proven by the null-move observation... >> >> > >It's still different from what I suggested. As Edward said: > >> >>> >>>applying david's suggestion to a null move implementation would >>>mean reducing the search depth after a null move failed high >>>instead of simply returning immediately with a fail high. >>> >>> - edward > >My idea is more general. Why do you waste all those nodes to reduce a single ply, what you do is simply leading to incorrect search, as depending upon alfa and beta you write to hashtable that a depth of search depth = n is having an x score but somewhere in the tree it actually searched because of a reduction n-1 ply. The reason why this probably this problem doesn't show much as if it does in FHR is because if nullmove goes ok then the whole rest of what you search in this position is no longer relevant. so a huge speedup of your program is then to give a cutoff after nullmove is > beta instead of searching on for the man with the short name. Greetings, Vincent
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