Author: Gerd Isenberg
Date: 15:15:33 09/15/04
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<snip> >>>Hsu's paper defined singular extensiosn for PV nodes and CUT nodes. His paper >>>said "we have found no useful definition for a singular move at an ALL node >>>however.." >> >>Hmm isn't the definition simply that there is one move which is by a certain >>amount better than all others, independent on pv-, cut- and all-node? > >No. There is a precise definition of a singular move, but the test is only >defined for PV and CUT nodes. At an ALL node there is absolutely no way to >determine if one move is better than all others. Maybe with fail soft and altered zero window bounds to check for one score > alpha - SMALL_MARGIN while all others are far below score <= alpha - BIG_MARGIN > > > >> >>Probably the forced situation, that there is only _one_ move (e.g. becomes >>alpha while all others are less alpha-margin), makes it worth to look deeper to >>look whether the all-node becomes a singular cut node or improves alpha, with >>possible influence at the root. > >That test won't work. Tests where the value is <= alpha or <= alpha-margin are >really meaningless in the context of alpha/beta/minmax search. That is why they >could not define a workable test for singularity at ALL nodes. I see. <snip>
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