Author: Dann Corbit
Date: 23:09:38 02/13/04
Go up one level in this thread
On February 13, 2004 at 12:51:08, Uri Blass wrote: >On February 13, 2004 at 12:41:41, Tord Romstad wrote: > >>On February 13, 2004 at 12:28:26, Mike S. wrote: >> >>>On February 13, 2004 at 11:07:02, Tord Romstad wrote: >>> >>>>(...) That several of the top commercial >>>>programs do not use null move (at least not in the conventional way) is >>>>further evidence that it is possible to come up with something better. >>> >>>Are you sure that there are top engines which don't use nullmove? Maybe they >>>"just" combine it with some zugzwang detection, or switch it off depending on >>>the amount of material earlier than other engines... >>> >>>(I think the last engine not using nullmove which was among the top was Chess >>>Genius, but that was many years ago.) >>> >>>I'm aware that some engines are not affected by the zugzwang/nullmove problem as >>>much as others are. - I'm only asking from the viewpoint of a user and fan, IOW. >>>no programmer: Is it ok to say, nowadays all top-10 (if not more) engines have >>>to have nullmove implemented in some way, because without they wouldn't be >>>competitive in terms of search speed? >> >>I guess all strong programs use what Cristophe once called "the null move >>observation", which consists of the simple fact that in almost all chess >>positions, there is at least one move which is better than doing nothing. >>Hence, in a wide sense of the term, all programs do indeed use nullmove. >> >>However, everybody does not use standard recursive null move pruning in >>the form popluarized by Chrilly Donninger in the ICCA Journal a few years >>ago. Chess Genius and Junior have already been mentioned. Two other >>examples are Rebel and Chess Tiger. >> >>Tord > >Rebel and chess tiger use null move pruning. >They use other reductions but the same also for you. At one time, Rebel did not use null move pruning (IIRC).
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