Author: Omid David
Date: 14:46:36 07/11/02
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On July 11, 2002 at 17:41:08, Uri Blass wrote: >On July 11, 2002 at 16:38:50, Omid David wrote: > >>As part of an extensive research (will be published soon), we tested null-move >>pruning with fixed depth reductions of R=2 and R=3 on about 800 positions of >>"mate in 4" (searched to depth of 8 plies) and "mate in 5" (searched to depth of >>10 plies). The results naturally show that R=2 has greater tactical performance >>(greater number of checkmate detection). > >This is not the right test. >It is clear that if you search to fix depth R=2 is going to be better. > >The question is what happens when you search for the same time. > > > However, we also conducted about >>hundred self-play matches under 60min/game time control between R=2 and R=3. The >>outcome is a rather balanced result (R=2 only a little better). Considering that >>the tests where conducted on a rather slow engine (100k nps), on faster engines >>R=3 is expected to perform better. > >I think that a better test should include different programs and not the same >program against itself. > >Another point is that R=2 and R=3 are not the only possibilities. >> >>So, apparently R=2 is not _by_far_ better than R=3 as some assume. > >I suspect that it is dependent on the program(results may be different for >programs with different qsearch and different evaluation). > >Uri I don't expect R=2 to gain more from greater speed than R=3. As a matter of fact as Dr.Hyatt recently mentioned with faster hardware in the future, R=3 might reach depths in which the total saving would be more significant than tactical deficiency (deeper search would compensate for it). In such cases one might even think of R=4 at some parts of the search tree (or as Dr.Hyatt just mentioned an adaptive R=3~4 value).
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