Author: Uri Blass
Date: 05:52:41 07/31/02
Go up one level in this thread
On July 31, 2002 at 07:55:51, Ulrich Tuerke wrote: >On July 30, 2002 at 15:02:25, Tony Werten wrote: > >>On July 30, 2002 at 13:56:53, Thorsten Czub wrote: >> >>>in an old program i can set the null move margin on or off. >>>what is the function doing ? any ideas or explanations from the programmers? >> >>I'll give it a guess. >> >>Normally when you do a nullmove and the score returned is > beta you get a >>cutoff. The idea is that if doing nothing already gives bigger than beta, doing >>something would give even more. > >You're probably right, Tony. This is an old idea, which had been already >suggested by the nullmove "inventers" Goetsch and Campbell themselves a long >time ago. I am surprised to hear it because I thought based on posts that at the time that null move was invented programmers were afraid from errors and did not dare to think about R=3. I thought that in this situation the inventors are going to be afraid of increasing the risk of null move pruning by other means. Uri > >I have played around with it several years ago. I came to the conclusion that >it's not worthwhile trying it (microscopically smaller search tree but >nevertheless a certain risk involved to damage the search). > >Uli > >> >>You can go one step further with this idea. Since doing something would be >>better than doing nothing, then doing nothing doesn't have to be > beta but only >>> beta - margin since I expect that a move is worth at least "margin" >> >>Tony >> >>> >>>what are the effects ? >>> >>>thank you. >>> >>>Thorsten Czub.
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