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Re: [computer-go] An [open] question on game tree search theory



Don Dailey wrote:

Usually at this point somebody will suggest that evaluations should be of the form "score + confidence estimate", i.e. that evaluations should consist of two numbers, evaluation score, and some form of evaluation of the confidence in the score. A generalization would be to let evaluations be probability distributions of evaluation scores.

If you view evaluation more as the probability of winning (where 0.5 == draw)
then evaluation which you have little confidence in could be pushed in the
direction of a draw, reflecting your lack of confidence in the reliability of
the score.

What is a probability of winning?

Probability that the playing algorithm will win against a hypothetical, fixed opponent mechanism---which is circular, because the evaluation function affects this probability? And what is the opponent model?

Or probability that the game tree node is a game-theoretic win? What does this mean? One game node is either win or not, so there is no stochastic experiment. You need to have a repeated experiment or a population larger than one object to be able to speak of probabilities.

I'm not being rude. I think this is one of the key points. "Probability of winning" is often mentioned, but what does it mean? Every node is a game-theoretic win or not, so no probability here. Results from actual game play, with our imperfect algorithms, depend on the opponents. Is there an opponent model implied? Against a perfect opponent, all algorithms that can make mistakes should evaluate the probability of winning to zero!

Please shew light on this!

Yours Truly,

--
Antti Huima (Mr.)
Director, Conformiq Tools
mobile: +358 40 528 8667
email: antti.huima@xxxxxxxxxxxxxxxxx

Conformiq Software Ltd.
Stella Terra, Lars Sonckin kaari 16
FIN-02600 Espoo, Finland
tel: +358 10 286 6300
fax: +358 10 286 6309 http://www.conformiq.com/

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