[computer-go] On expanding the UCT tree

[Vlad Dumitrescu]

Hi,

see below

On 5/7/07, Peter Drake <drake at lclark.edu> wrote:
> In the first playout, my first move is A, so then I have:
>
> ROOT 1
>         A 1
>
> Now I try move B, updating the tree to:
>
> ROOT 2
>         A 1
>         B 1
>
> Fine so far. Now UCT likes A better, so the next playout starts with
> A, C, giving me:
>
> ROOT 3
>         A 2
>                 C 1
>         B 1
>
> Here's the problem. On the next playout, I'll want to look at the
> other alternative to A. In doing so, I will need to compute the UCT
> value of trying C again, especially if (as in the Gelly tech report)
> I don't automatically choose untried moves over tried moves. When I
> look through the children of A and count a total of one playout, it
> seems natural that I should update the playout count for A:
>
> ROOT 3
>         A 1
>                 C 1
>         B 1

I am sorry, I may be much too tired right now, but why should A=C+D?
Isn't it C+D+1, because A was also evaluated as a leaf? (this requires
the root to be initialized at 1)

best regards,
Vlad