Author: Tom Kerrigan
Date: 15:23:05 07/25/00
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On July 25, 2000 at 17:52:08, KarinsDad wrote: >On July 25, 2000 at 14:12:46, Tom Kerrigan wrote: > >>It would be nice to make a change to your evaluation function and get immediate, >>accurate feedback. >> >>So my idea is to get a huge collection of positions of known value (i.e., "white >>has a stronger position") and then see how well the known values correlate to >>the evaluation function's scores. >> >>Does anybody have any ideas for getting a high-quality collection of such >>positions? Or any comments on this approach in general? >> >>-Tom > > >The problem I see with this idea is that although it sounds fine on the surface, >I do not see a way to implement it. > >For example, say your program says that position A is advantage white 0.2 pawns. >What happens when you change your evaluation and it now says advantage white >0.26 pawns. Did you improve your evaluation code or make it worse? > >And what omnipotent being or program decides that position A is really a 0.22 >pawns advantage for white? Ditto for the rest of the positions in the >collection. Right. I think the only way to go is binary, i.e., "positive" instead of +0.22. So the evaluation can be either right or wrong. Let's say you have a collection of 10,000 positions where you know which side is winning. You run your evaluation function on these positions (which should only take a few seconds) and get some output like: Eval function correct for 8,000 (80%) of the positions. Then you tweak the eval function and get 82%. You know your tweak was beneficial. -Tom
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