For clarity, I show the rule by your example: 3 O O X X X O O O
2 X X O O O X . .
1 . X . O O . X .
- - - - - - - -
A B C D E F G HWhen C1 is detected to be forbidden selfatari and it is also
an atari, then play F1 instead.Aja----- Original Message -----
From: Go Fast
To: [email protected]
Sent: Saturday, December 04, 2010 3:14 AM
Subject: Re: [Computer-go] Tactical misevaluations in Fuego MCTS
a correction to the diagram below
On Fri, Dec 3, 2010 at 2:11 PM, Go Fast <[email protected]> wrote:
I have similar experiences.Two liberty blunder appears after fixing one
liberty blunder. And 3-lib blunder appears after fixing two liberty blunder.
I have one test case similar as following diagram. All other places are
mostly settled, except the bottom three string.
O O X X X O O O
X X O O O X . .
. X . O . X .
- - - - - - - -
In most cases, StoneGrid's playout ends up with the left bottom corner
being killed. With self-atari analysis, either side will not play self atari
moves, which is right behavior. However, without analysis on the 3-lib string,
the chance for the black to find the right move in the random playout is very
small. It is far less than 1/2. As when black plays randomly at one of its two
outside libs, it will bring the white to play around it, and end up with black
being killed.
On Fri, Dec 3, 2010 at 10:45 AM, Brian Sheppard <[email protected]> wrote:
>Is the problem as bad as in Fuego?
Maybe not this specific problem, but similar problems.
Approaches like adding a 2-liberty feature helped Pebbles. But the
difference is not as large as you would like.
For example, your program will shred other programs that lack a 2-liberty
feature. But humans have a 2-liberty feature, and a 3-liberty feature, and
so on. And if the human is of sufficient rank, then his error rate on
those
features is quite small.
So you still run into problem cases. It just happens one move later than
before.
Note that the combinatorics suggest that 3-liberty features will be very
hard to write correctly. A 2-liberty feature is mostly branch-free. E.g.,
one player ataris, and the response is to capture if possible and escape
otherwise. When you have 3-liberty features, there are now 2 ways to
escape.
Additionally, you can defend by capturing or by reducing an opponent to 1
liberty.
Even the 2-liberty feature is hard to get right. I expect to be fixing
mine
for many years.
Brian
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