Author: James Swafford
Date: 08:48:44 01/06/01
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On January 05, 2001 at 17:36:55, Bas Hamstra wrote: You're a little ahead of me. I've been wanting to do some work with TD for some time, but I've still got a couple months of work to do before I even get started. I do have a couple questions for you, though: 1. Did you start with realistic weights, or did you begin with random values, or ??? 2. What do you mean by "wrong trend?" I suppose you mean a term is "drifting" the wrong way... becoming more negative when it should be going more positive? 3. How are you training your evaluator? With a wide variety of opponents, or by playing the same programs over and over, or ??? How many games have you played? 4. Does your engine compete on ICC? -- James >I would like to share experience with some that have tried Temporal Difference >learning. Currently one of the problems I see is that for example BISHOPMOBILITY >has very large partial derivatives. So the updates for this term swing wildly >and distort learning. On the other hand, if I reduce the learning factor to >bring this in proportion, a term like DOUBLEDPAWN won't ever get to a realistic >value. > >One way to do better is to work with derivatives -1 or +1 only, depending on if >the partial derivative for a term is above or below zero. This results in a >tendency to realistic values for most terms. > >Still, a few terms refuse to show a "trend" at all, or even the wrong trend. Are >others having this problems? > >(To see what is going on I showed the developments of the weights in a graph, to >verify it does something useful, best results so far with -1/+1 only, bad >results when using the real derivatives) > > >Regards, >Bas.
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