Author: Omid David Tabibi
Date: 02:01:31 11/21/02
Go up one level in this thread
On November 21, 2002 at 00:09:49, Jeremiah Penery wrote: >On November 20, 2002 at 22:05:29, Robert Hyatt wrote: > >>On November 20, 2002 at 16:55:41, Gian-Carlo Pascutto wrote: >> >>>Nullmove in Deep Sjeng uses an algorithm of my own, but I can >>>switch it back to other systems easily. I did so for running >>>a few tests. >>> >>>I made a version which uses Heinz Adaptive Nullmove Pruning >>>and a version which uses your verification nullmove. >> >>This would seem to be a bit harder than at first glance. They say that >>if the normal null-move search fails high, then do a D-1 regular search >>to verify that, but while in that verification search, no further >>verification searches are done, meaning that the normal null-move search >>fail-high is treated just like we do it today.. >> >>I'm going to experiment with this myself, just for fun, but it seems that you >>need to pass some sort of flag down thru the search calls indicating that >>you are either below a verification-search node or not so that recursive >>verification searches are not done... > >I tried implementing it in Crafty, as it is done in the pseudo-code in the >paper. I wasn't sure exactly where to place the block with the goto, and since >Crafty has no 'best' variable in search, I wasn't sure what to put there either. > However, the algorithm did seem to work ok, though it didn't result in a >smaller tree that I could tell. I didn't get a chance to compare it to the >normal Crafty in many positions, or for a very long time, however. Leave alone the zugzwang detection for now (other parts don't need a 'best' variable).
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