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

[steve uurtamo]

yes, and the fact that turning a dumpling into a dead
group can take more than a few moves, since you may
have to fill up the eyespace several times, meaning
going fairly deeply down branches with several self-ataris
along the way.

s.

On Thu, Mar 6, 2008 at 9:23 AM, Don Dailey <drdailey at cox.net> wrote:
>
>
>  >
>  >
>  > You won't find that in computer vs computer games, because "tricking" the
>  > strong programs requires some go skill and it only works if you wait long
>  > enough before you "solve" the position. But if you search KGS (LeelaBot,
>  > CrazyStone, CzechBot) for even games where the bot lost against a kyu
>  > players you will find many. All go more or less like that:
>  >
>  > A 4-6 kyu human is behind by 10-15 points in the midgame (at that
>  > stage the
>  > probability of winning is correlated with territory, so the MC bot is
>  > building fine.) He creates a 12-16 point worth nakade trick in a corner
>  > and does not solve it.The bot is happy, it thinks a bulk five is alive or
>  > something like that. Perhaps the human sacrificed another 15 points
>  > somewhere to create the trick so he should be dead lost. But, he only
>  > has to play on, reduce, etc. As the endgame approaches, the MC bot
>  > allows the reduction only until the territorial balance would change the
>  > winner. The player is happy, he turned a 25 points loss into a 1.5 point
>  > loss (assumed by the program) and has a 12 point surprise.
>  > At the end, when the whole board is decided, the player kills
>  > the bot's group and the bot turns a sure win into a sure loss and
>  > resigns.
>  >
>  > Because the trick can only be played by similar strength players (much
>  > weaker players can't build something like that, much stronger don't
>  > need it)
>  > it affects the rating of the bots. I guess CrazyStone could be near
>  > KGS 1dan
>  > with that solved. It is 2k now. But, of course, the solution may not
>  > come at
>  > the price of making the program weaker. That is the difficult part.
>
>  I want to make sure I understand the nakade problem,   please correct me
>  if I am wrong:
>
>  My understanding of this is that many program do not allow self-atari
>  moves in the play-outs because in general the overwhelming majority are
>  stupid moves.   Is that what is causing the nakade problem?     And if
>  you start including self-atari you weaken the program in general?
>
>  And can I assume the tree portion is also inhibited from seeing this due
>  to a combination of factors such as heuristics to delay exploring "ugly"
>  moves as well as  the weakness of the play-outs in this regard (which
>  would cause the tree to not be inclined to get close enough to the issue
>  to understand it properly?)
>
>  - Don
>
>
>
>
>
>  >
>  >
>  > Jacques.
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