Author: Omid David Tabibi
Date: 01:52:13 11/21/02
Go up one level in this thread
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... > Exactly!! (finally someone read the article carefully) See Figure 3 for detailed implementation (the flag you mentioned which is passed down as a parameter for search(), is called 'verify' in the pseudo-code). At first stage leave alone the zugzwang detection part (the piece of code at the bottom of Figure 3). Due to instablilities, some programs might do a needless re-search. First let the algorithm work fine in general, and then do the zugwzang detection part. I'm looking forward to your results in Crafty...
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