Author: Bo Persson
Date: 14:15:13 06/22/05
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On June 22, 2005 at 10:01:12, Vincent Diepeveen wrote: >On June 21, 2005 at 16:11:50, Bo Persson wrote: > >>On June 20, 2005 at 08:06:08, Vincent Diepeveen wrote: >> >>> >>>If at 13 ply the score of other moves is 0.35 or so and from this root move it's >>>0.400, then we have a 100 point difference between 0.300 and 0.400. >>> >>>Now we need possibly a 100 researches to get to 0.400, but at least 2 dozen or >>>so. As we will use bounds 0.300 0.301 0.302 0.303 0.304, hoping that the score >>>is close to 0.300 of iteration 12 of course. >>> >>>PVS is far superior in this as we can determine the true bound directly by >>>taking the tree of 12 ply search depth. We add 1 ply to it and we already have a >>>root score of real close to 0.400 to it. So for the price of a node or 50 using >>>hashtables we directly determine a true bound or somethign real close to the >>>true bound, where MTD needs 20+ researches for. >>> >>>Is my point clear now? >> >>This is the usual Vincent thing - he can't get it to work, so it just doesn't >>work. >> >>Who said you had to add 1 millipawn for each research? You can accellerate the >>step (+16, +32, +64, etc), until you step over the target, and then zoom in >>again. >> >>To go from 0.300 to 0.400, my program tries this series: >> >>0.300 0.316 0.348 0.412 (fail low!) 0.380 0.396 0.404 0.400 >> >>That's eight (8) searches, not 100, not even 20+ ! > >>Bo Persson > >By not using step 1 initially you remove all advantages that MTD *might* offer. No. If the final score would actually be 0.301, I would go 0.300 0.316 0.308 0.304 0.302 0.301 That's 6 null window searches. Not bad. Of course, if the new score just happened to be 0.316, I would find it really fast! Why optimize for the 0.300 -> 0.301 case? Is that very frequent in your program? Bo Persson
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