Author: Vasik Rajlich
Date: 05:01:04 09/26/04
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On September 26, 2004 at 00:47:14, Sergei S. Markoff wrote: >>I would be unsure about possibly returning incorrect score >= beta in the >> first stage. > >Sometimes it happens because of the change of values of the root bounds. In a >root we have (in classic scheme of course) exact score for the best move. Near >the zugzwang positions happens one thing. Some move fails high because of >null-move cutoff. And we doing re-search with more wide window. In this case the >zugzwang will be avoided using method, inroduced by me. > >>will not work well with score <= beta logic, whatever beta may be. Also depth >>differences in nodes vastly affect the score, whether null move or not. > >The depth diffenences will be in most cases compensated by window width between >null move score and best move score. Anyway the error will be only if a score >delta is not in a bounds of this window + root aspiration window. Is it need to >explain this? Is the case too often? We need experiments. Keep in mind that most wrong null-move fail highs are due to the depth reduction rather than zugzwang. Still - the idea might be useful to prevent null moves in positions where the depth is needed. Vas
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