[computer-go] Lazy Evaluation in Monte Carlo/Alpha Beta Search for Viking4

[Rémi Coulom]

Don Dailey wrote:
> I wasn't very clear about one of these points (and Remi just posted a
> clearer explanation of the same technique I use.)

My idea was maybe not quite the same as yours. From what I understand of 
your message, you decide about pruning based on the fudged value 
directly. My idea was to use the fudged value as an estimate of the move 
value, and still use alpha * sqrt(sigma²/N) as the size of the 
confidence interval around the fudged value.

I believe your approach is dangerous, because your confidence intervals 
shrink as 1/N. They should shrink as 1/sqrt(N). Your idea might work in 
practice, but it does not look very consistant with theory. My idea of a 
fudge can be justified in the Bayesian framework in terms of a "safe 
prior". It applies to the estimation of the value, not the confidence 
bounds.

Rémi