[computer-go] New scalability study : show uncertainty ?
Jacques Basaldúa
jacques at dybot.com
Wed Jan 23 05:21:33 PST 2008
> I don't think "only uniformly random playouts will scale to
> perfection" because what we need for playouts is not just a simple
> average of final scores but a maximum (in negmax sense) score. It
> should be the perfect evaluation function.
> In other words, as MC simulation is a way to get an average of a
> value, when applying it to optimization problems we need some way to
> focus the simulations to the _peak_ in a state space.
> It may be obvious when one consideres L&D problems where the best move
> that leads to the maximum score (live) is only one and all other moves
> are bad. At such positions it's almost no sense to simulate all legal
> moves with same probability. So, IMHO, biasing simulations is not
> just a speed-up technique but is essentially important.
I agree, but what I meant about uniformly random playouts is the following:
What makes a move outstanding is being unpredictable. For a total novice,
playing at the key point of a bulky five may look like a touch of genius,
but when you learn a little, its an obvious move. The difference between a
5p and a 9p may be one or two moves nobody can predict (except a 9p). When
we add knowledge we find the _ordinary_ good moves faster, we make weaker
moves less probable, but that comes at a price, the price of making outstanding
unpredictable moves less probable also. Perhaps that introduces a ceiling.
I thought that was what you were also pointing. Of course, I don't claim
uniformly random playouts are good, I just claim that they should (just as an
infeasible theoretic argument) scale to perfection, of course that scaling
doesn't have to be linear.
Jacques.
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