Author: Robert Hyatt
Date: 18:26:32 09/06/02
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On September 06, 2002 at 20:35:26, Dann Corbit wrote: >On September 06, 2002 at 15:47:50, Robert Hyatt wrote: > >>On September 06, 2002 at 14:45:11, Dann Corbit wrote: >> >>>Did anyone notice his cutoff idea in the evaluation function? >>> >>>It seems to me to be a very good idea, and I don't know if others have tried it >>>out. >>> >>>Basically, it consists of three modes with two early exits... >>> >>>1. If the material + structure score alone is dominant enough, it exits right >>>away. >>>2. Otherwise, it processes the piece list. If that score is dominant, it exits. >>>3. Otherwise, it does a full board control scan for all 64 squares. >>> >>>It is described starting on page 62 under the section "3.3.2 Multi Staged >>>Design" >>>He gets roughly 71% evals returning in stage #1, 13% in stage #2 and 7% in stage >>>#3. >>> >>>It seems like it might be a big win to do it that way. >> >> >>That is called "lazy evaluation". Most of us do that. :) > >Yes, most programs have a lazy evaluation. But the exact nature of the >divisions is what I found interesting. Each additional stage of eval is a big >jump in complexity. > >I don't think any of the programs I have examined divide the effort into exactly >those categories. And most of them have a two stage lazy eval (test and do the >full thing or don't). The three stage idea looked interesting. Crafty does it about 1/2 way into the eval. I do the stuff that can produce enormous scores like passed pawns that can't be stopped, and then I lazy exit before the slow piece evaluations if possible...
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