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Subject: Re: Temporal Difference

Author: James Swafford

Date: 11:34:09 01/06/01

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On January 06, 2001 at 12:11:32, Bas Hamstra wrote:

>Hi James!
>
>On January 06, 2001 at 11:48:44, James Swafford wrote:
>
>
>I started with all weights zero. To see it did something reasonable, I let it
>play a pool of 100 slightly randomized hand-tuned evals. You don't need 100
>programs, just 100 weight sets and one program. It then learns to score 50% in
>200 or 300 games. I plotted the weights real time in a graph to see how they
>developed. This was my first test. Second step was to put it in my console based
>"real" program and it is playing Crafty right now.

Seems to me it would help things along if you started with reasonable
values.  I think Tridgell / Baxter started with all weights = 0, too,
with KnightCap, and remarked the same thing.

>
>>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?
>
>Yep. Say 90% of the weights tend to show reasonable values. But a few don't at
>all. It might be that it needs more games, though. I am not sure if this is the
>fastest way of automatic parameter tuning. Maybe some kind of "weight fitting"
>on a large set of positions is more efficient, but how?

What would happen if you "moved" those weights to where you think they belong?

>
>>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?
>
>Right now I am playing Crafty for a couple of hundreds of 1 0 games.

Hmmm.... so you're training your evaluator to play the best it can
against Crafty at 1 0.  Why not ICC (or FICS) against a wide variety
of opponents?  I'd prefer slightly slower time controls, too, although
I know with that many games time gets to be a problem...


>
>>4.  Does your engine compete on ICC?
>
>A couple of times. But mostly FICS. The TD version has not played there yet. By
>the way: I compared what it learns from a) wins b) losses c) draws. In my
>opinion a) and c) did not do well. So now I only learn from losses. Never change
>a winning team.

Yes, that makes sense.  Thanks for the info!  Maybe we can share notes
in a few months...


--
James



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