Re: [computer-go] 2nd KGS Computer Go Tournament

[Nick Wedd <nick@xxxxxxxxxxxxx>]

In message <427F0B79.1040904@xxxxxxxxxxxxxxxxx>, John Tromp <John.Tromp@xxxxxxxxxxxxxxxxx> 
writes
> John Davies wrote:
>
> > Your suggestions on the linked web page seem good but I'd argue with one
> > of them: if bots HAVE to kill off every enemy stone it will cost them
> > time to do it.  As author of one of the few programs that tried to
> > maximise it's use of time carefully (shame about the quality of moves!)
> > I wouldn't be keen on this approach.
I am going to step down on this one.

I will certainly not _require_ bots to remove dead stones;  I know that 
it won't work, most programmers simply won't do it.  I will merely say 
that if a bot _does_ remove dead stones, I shall be grateful to it.

> I disagree. If programs disagree on the status of groups, then
> the only fair way to resolve this is to let them play it out.
> You can't have either program saying
> "well, those stones are dead but i can't be bothered to show it".
If the problem were genuine disagreement, I would agree with John.  But 
it isn't.  Some bots have game-end-handling code which is much worse at 
assessing status than their actual playing code.  For instance, LeGoBot 
plays at around 20k, but in its first-round game, it claimed at the 
game-end that its one-liberty black group, entirely surrounded by 
unkillable white groups, was alive.  LeGoBot's playing engine knew it 
was dead, the error was merely in its scoring engine.

Of course I would prefer it if LeGoBot could score properly, but this is 
not a big problem, I can live with it.

In my experience bots are pretty effective at attacking and defending 
groups which are, or which might possibly be, unsettled.  I don't mean 
that they do it competently, just that they do it, until the status is 
resolved.  So it is rare for a group with any genuine doubt about its 
status to be on the board when they both pass.

I have only once had to deal with a situation where an unsettled group 
was left on the board at the end of a computer/computer game.  This was 
the game Aya (the same Aya that won the recent KGS event) versus Indigo, 
in the MSO, London, 2000.  The unsettled 78-stone group belonged to 
Indigo, and Indigo's owner conceded (as was evident from the play) that 
Indigo thought it was dead.

Nick
--
Nick Wedd    nick@xxxxxxxxxxxxxxxxx
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