Author: J. Wesley Cleveland
Date: 10:53:37 01/01/02
Go up one level in this thread
On January 01, 2002 at 13:10:33, Vincent Diepeveen wrote: >On December 31, 2001 at 21:32:24, J. Wesley Cleveland wrote: > >>On December 31, 2001 at 05:28:54, Dann Corbit wrote: >> >>>On December 31, 2001 at 05:26:11, Michel Langeveld wrote: >>>>I want to check how efficient Nullmover is. >>> >>>By how often you fail high on your first choice. >> >>Note that this is somewhat deceptive, e.g. crafty gets about 90% failhighs >>first, but often visits twice as many nodes as the minimum. A more accurate way >>is to compare the total number of nodes visited to the minimun. The recursive >>algorithm to count this is relatively straightforward: >> >>if (failhigh node) >> minimum_nodes = minimum_nodes(fail_high move) + 1 >>else >> minimum nodes = sum for all legal moves(1 + minimum_nodes(move)) > >Problem to determine minimum is nullmove reduction factor. >It completely depends upon how you extend crazy tactical moves because >after tactical move your nullmove will nearly always fail. If a nullmove causes a cutoff, the nodes visited are part of the minimum. Hashing causes much larger problems, as a move which appears to be unnecessary could add hash table entries that cause cutoffs later. I think of this as a rough estimate more than an exact figure, but believe it is much more accurate than fail high first percentage.
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