[Computer-go] I need an off-the-shelf final position live/dead evaluator

David Fotland fotland at smart-games.com
Sun Nov 28 11:13:12 PST 2010

At the end of the game mcts is pretty good at life and death, but rarely
gets the exact score.

> -----Original Message-----
> From: computer-go-bounces at dvandva.org [mailto:computer-go-
> bounces at dvandva.org] On Behalf Of Dave Dyer
> Sent: Sunday, November 28, 2010 11:02 AM
> To: computer-go at dvandva.org; computer-go at dvandva.org
> Subject: Re: [Computer-go] I need an off-the-shelf final position
> live/dead evaluator
> At 07:16 AM 11/28/2010, Michael Williams wrote:
> >On Sun, Nov 28, 2010 at 4:15 AM, Dave Dyer <ddyer at real-me.net> wrote:
> >> At 10:39 PM 11/27/2010, David Fotland wrote:
> >>>Accurate scoring, even at the end of a game, is very difficult.  You
> have to
> >>>read accurately, and evaluate semeai and seki.
> >>
> >> Yup.  I spent years developing the capability to score endgames
> >> at the point where humans typically leave them.  Getting within
> >> a few points of correct 95% of the time is achievable.  The other
> >> 5% you will either make whopper mistakes or never terminate.
> >>
> >> This is now pretty old, but I don't know of any more recent or better
> >> results. http://www.andromeda.com/people/ddyer/go/scoring-games.html
> >
> >No one here or at that link mentions whether they are talking about
> >Chinese scoring or Japanese scoring.  It seems that the there would be
> >a significant difference.  For insnance, if I wanted to score a
> >Chinese endgame starting with no code, I would probably write an MCTS
> >move generator that played the game to the bitter end and then score
> >it using simple area counting.  But you can't do the same thing with
> >Japanese scoring.
> The referenced page was based on Japanese scoring, and treated the
> board position as a semi-static position.  One part of the process
> involved filling the dame in a controlled way, to allow mandatory
> responses as necessary, but that was after it had decided what was
> supposed to end up alive.
> It's a good question if MCTS would get the right answer in those
> 5% cases - one characteristic is that they are poised on the brink
> of life or death, where there is frequently exactly one sequence
> that determines the "correct" outcome.  It seems to me that MCTS
> would tend to say "it's alive 99% of the time' when the correct
> answer is that it's 100% dead.
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