endgame (Was [computer-go] Re: Should 9x9 komi be 8.0 ?])

[David Fotland]

If there is an illegal ko point on the board Many Faces includes ko threats
in move generation, and it will play a ko threat if it is the best move
found.  So there is no special heuristic for ko other than generating more
possible moves.

David

> -----Original Message-----
> From: computer-go-bounces at computer-go.org [mailto:computer-go-
> bounces at computer-go.org] On Behalf Of Gunnar Farnebäck
> Sent: Monday, March 03, 2008 11:34 AM
> To: computer-go
> Subject: Re: Re : endgame (Was [computer-go] Re: Should 9x9 komi be 8.0
> ?])
> 
> Don Dailey wrote:
>  > How do the classic programs handle these sequences of ko threats
> that
>  > must be precisely calculated to extreme depths?
> 
> Usually with big difficulty and crude heuristics.
> 
> GNU Go determines that it should play a ko threat if the top move
> turns out to be an illegal ko capture. In that case the top move is
> removed from consideration and other moves are reevaluated by adding
> the value of followup moves. After that the new top move is chosen,
> which may be a ko threat if it's big enough and otherwise the
> originally second move.
> 
> The difficulty is of course to determine the followup value, which
> tends not to be very exact at all, and far from all threats are found
> in the first place. Still GNU Go can play ko decently, at least
> compared to its general level of play.
> 
> /Gunnar
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