Author: Chris Welty
Date: 11:30:21 08/31/04
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On August 31, 2004 at 10:28:04, Robert Hyatt wrote: >On August 31, 2004 at 08:22:20, Chris Welty wrote: > >>On August 30, 2004 at 17:01:57, Robert Hyatt wrote: >><snip> >>>>Auto-tuning would be great. My problem is I don't know how to do it. If you >>>>have a method I'd love to hear more. >>>> >>>>Dan H. >>> >>> >>>It is also a _very_ hard problem. >>> >>>_very_ hard... >> >>It was quite easy to get Altamax to autotune its evaluation parameters so that >>it played substantially better than the hand-tuned version. It took less time >>than hand-tuning too. >> >>Getting autotuning to work WELL required some work, but was still easier than >>hand-tuning the coefficients. >> >>I use TD-leaf, which I got from some paper on the internet. >> >>Chris > > >How many different terms? Crafty has a bunch. auto-tuning them to be better >than the hand-tuned default has not happened yet although we have (mainly >Anthony) beat on it mercilously. Crafty has about 120 different eval features >that can be adjusted, with maybe 1/2 of them represented as large arrays of >values. Easily over 1000 different values to adjust. A tough task as I said... When I did the initial comparison, about 75 terms. Since autotuning is easy I've added lookup tables; now there are a total of 570 numbers that can be adjusted. The piece-square table numbers do look strange (-0.95 pawns for a bishop on D8??) but the results are good. I suspect it also depends on how good you are at hand tuning.
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