Computer Chess Club Archives




Subject: Re: Doesn't appear to work for me (full data)

Author: Omid David Tabibi

Date: 01:59:26 11/21/02

Go up one level in this thread

On November 21, 2002 at 02:34:29, Gian-Carlo Pascutto 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...
>Uh, considering psuedocode is given, this is a pretty braindead thing
>to implement. Yes, you need to pass a flag down, as is illustrated in
>his code.
>The only tricky thing is the research on zugzwang, but I guess botching
>that is not as critical if you run purely tactical tests?

At first stage, you can just neglect the zugzwang detection (the block of code
at the bottom of Figure 3). When the algorithm works fine in general, then do
the zugzwang detection part.


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