Re: [gnugo-devel] bug

[bump]

> Hi,
> 
> Here it is! After twogtp crashed, as gnugo saved the gtp commands, I ran 
> ~/gnugo-3.6-pre2/interface/gnugo --mode gtp -r 54 < gnugo-black.gtp, and 
> got :
> 
> ***assertion failure:
> owl.c:6129 - IS_STONE(board[pos]) near H7***

Thanks, Tristan.

What I don't understand is that Tristan's sgf output
only shows 11 stones on the board. 

However 24 moves have been played in the second game!
This position does not seem to represent the same game
at all. (Either game.)

***assertion failure:
owl.c:6129 - IS_STONE(board[pos]) near H7***

W:E7 B:F7 W:F8 B:G4 W:G8 B:G2 W:H4
   A B C D E F G H J
 9 . . . . . . . . . 9
 8 . . . . . O O . . 8
 7 . . + . O X + . . 7
 6 . . . X O X . . . 6
 5 . . . . + . . . . 5
 4 . . . . O . X O . 4
 3 . . + . . . + . . 3
 2 . . . . . . X . . 2     WHITE (O) has captured 0 stones
 1 . . . . . . . . . 1     BLACK (X) has captured 0 stones
   A B C D E F G H J
(;GM[1]FF[4]SZ[9]KM[5.5]GN[GNU Go 3.6-pre2 stepped on a bug]
;B[fd];W[ef];B[dd];W[ed]
)

I tried this gtpstream on two machines. With gcc 3.3.3 there
was no problem, but with the obsolete gcc 2.96 20000731 I got
a different outputstream.

The moves are identical for the first game but the
scores differ. With gcc 3.3.3 the final score is
B+12.5 while with gcc 2.96, the final score is B+13.5.

The moves begin to diverge in the second game. With
gcc 3.3.3 B generates the following moves:

F6 D6 E7 G6 C6 F7 B8 C8 B6 A7 G8 A9

Here is the final position:

   A B C D E F G H J
 9 X . . . . . . . . 9
 8 . X X O O O X . . 8
 7 X O O O X X + . . 7
 6 . X X X O X X . . 6
 5 . . . . O . . . . 5
 4 . O . . O . . . . 4
 3 . . + . . . + . . 3
 2 . . . . . . . . . 2     WHITE (O) has captured 0 stones
 1 . . . . . . . . . 1     BLACK (X) has captured 1 stones
   A B C D E F G H J

With gcc 2.69, B generates the following moves:

F6 D6 E7 G6 C6 F7 C7 C4

Then the input stream has W C7, so GNU complains about
an illegal move. The game continues

D3 C8 G8 B5

and there is no crash.

   A B C D E F G H J
 9 . . . . . . . . . 9
 8 O . X O O O X . . 8
 7 . O X O X X + . . 7
 6 . . X X O X X . . 6
 5 . X . . O . . . . 5
 4 . O X . O . . . . 4
 3 . . + X . . + . . 3
 2 . . . . . . . . . 2     WHITE (O) has captured 0 stones
 1 . . . . . . . . . 1     BLACK (X) has captured 0 stones
   A B C D E F G H J

So I am seeing compiler variability but still cannot
reproduce the crash.

Dan