[gnugo-devel] Re: [computer-go] low-hanging fruit - yose

[Alain Baeckeroot]

Le mercredi 12 décembre 2007, Gunnar Farnebäck a écrit :
> Heikki Levanto wrote:
>  > On Mon, Dec 10, 2007 at 04:08:48PM -0500, Don Dailey wrote:
>  >> Would you rather be 95% confident of a win or 90% confident?    There is
>  >> only 1 correct answer to that question.
>  >
>  > Yes, if you can offer me reliable confidence numbers. We all (should) 
> know
>  > that MC evaluations suffer from systematic problems that can not just be
>  > averaged away statistically.
>  >
>  > Compare these two positions:
>  >
>  > playout_benchmark 10000
>  > = Initial board:
>  > komi 7.5
>  >    A B C D E F G H J
>  >  9 . . . . . O O O O 9
>  >  8 O O O O O O O O O 8
>  >  7 O O O O O O O O O 7
>  >  6 O O O O O O O O O 6
>  >  5 # # # # # # # # # 5
>  >  4 O O O # # # # # # 4
>  >  3 O O O O . # # # # 3
>  >  2 . O O O . # # # . 2
>  >  1 # . O O . # # . # 1
>  >    A B C D E F G H J
>  > Performance:
>  >   10000 playouts
>  >   0.032002 seconds
>  >   312.481 kpps
>  > Black wins = 1937
>  > White wins = 8063
>  > P(black win) = 0.1937
>  >
>  >
>  > playout_benchmark 10000
>  > = Initial board:
>  > komi 7.5
>  >    A B C D E F G H J
>  >  9 . # . . . O O O O 9
>  >  8 O O O O O O O O O 8
>  >  7 O O O O O O O O O 7
>  >  6 O O O O O O # # # 6
>  >  5 # # # # # # # # # 5
>  >  4 O O O # # # # # # 4
>  >  3 O O O O . # # # # 3
>  >  2 . O O O . # # # . 2
>  >  1 . . O O . # # . # 1
>  >    A B C D E F G H J
>  > Performance:
>  >   10000 playouts
>  >   0.084006 seconds
>  >   119.039 kpps
>  > Black wins = 7746
>  > White wins = 2254
>  > P(black win) = 0.7746
>  >
>  >
>  > Which one is better, 77% or 19%?
> 
> This reminds me of the first testcase I wrote when I started with
> MonteGNU. Black to play, no komi.
> 
>     A B C D E F G H J
>   9 . . O O X . X . X 9
>   8 . . . O X . X O X 8
>   7 O . O O X X O O X 7
>   6 O O O . X . X O O 6
>   5 X X X X X O O O . 5
>   4 . . X . O O . O . 4
>   3 X X O X O . + O . 3
>   2 X X O X O . . O . 2
>   1 . O O O O . . . . 1
>     A B C D E F G H J
> 
> Naturally B has to play B8, or white plays there and wins big. This is
> trivial to find for a classic program and easy enough for a Monte
> Carlo program. What's interesting is that it takes some work to make
> black think that it has better than even winning chances after B8. The
> Monte Carlo code in GNU Go CVS version gets 0.079 with 10k, 0.387 with
> 100k, and 0.475 with 1M simulations. I suspect that stronger programs
> tend to be more optimistic about winning chances here. So please fill
> in this table if you have an MC program:
> 
>               10k    100k   1M
> --------------------------------
> GNU Go CVS   0.079  0.387  0.475
> 
> The sgf file is attached, load it before the first move. The positions
> before move 3 and 5 are also relevant tests.
> 
> /Gunnar
> 

Can't this test be used to find a threshold for not playing in
opponent_territory_with_likehood_greater_than_N%

I mean 
H1 is W territory with very high probability,
B8 is W with some rather high probability (even if B can kill)

so cutting search to prevent (like standard gnugo) B trying moves
in H1 territory might help to find b8 quickly ?

Or maybe i misunderstood something ?
Alain