# [Computer-go] Results from 19x19 Valkyria/1k H9 vs Valkyria/10k

Heikki Levanto heikki at lsd.dk
Wed Oct 6 02:00:55 PDT 2010

```On Tue, Oct 05, 2010 at 04:28:40PM -0400, Álvaro Begué wrote:
>
> The correct way to evaluate an action is the expected value (yet
> another name for the mean) of the utility function (there is a theorem
> http://en.wikipedia.org/wiki/Von_Neumann%E2%80%93Morgenstern_utility_theorem
> ). Since we want to win the game, it makes sense to use a utility of 1
> for winning and 0 for losing, and this means that the probability of
> winning should be maximized. As far as I can tell, the theory ends
> there.

I agree that we should play the move that is most likely to win, given
reasonable play from both parts (say, play that approximates theoretically
best, with some errors thrown in). I do not necessarily agree that the theory
quoted above says much about how to estimate this probability using more or
less random playouts. Calculating the winning rate after each move, using a
selective tree search and random simulations sounds like reasonable
assumption, and it seems to work quite well, but that seems well outside the
VNM theory.

Just my simple 2 cents.

-Heikki

--
Heikki Levanto   "In Murphy We Turst"     heikki (at) lsd (dot) dk

```