[gnugo-devel] New semeai patch

[SP LEE]

In the attached game of gnugo 3.3.22 played on NNGS, gnugo played rather 
strangely, lost a winning game. This is a good case of semeai, black should 
play R12, but gnugo played O13 which gave white a lot of chance to thrash 
around.

  A B C D E F G H J K L M N O P Q R S T
19 . . . . . . . . . X O . . . . . . . . 19
18 . . X . . . . . . X O . O . X . . . . 18
17 . . . . . . X X . X O . . O . . . . . 17
16 . . . X . X O O X X O . X . . X . . . 16
15 . . X X . X X O O O O X . . . . . . . 15
14 . X . X O O O O . . O X . X X . . . . 14
13 . . X O O . . O X X X O X . O X X . . 13
12 . X X O . . X X O X O O O O O O . . . 12
11 . O X O X . . . O X X X O . X . . . . 11     WHITE (O) has captured 2 
stones
10 . O O X X X X . O X . X O . X X . . . 10     BLACK (X) has captured 2 
stones
9 . X O O . O X O O . O X O O O . X . . 9
8 . . X O O . O . O . O X X X . O X X . 8
7 . X . X O O X O O . . X . O O O O X . 7
6 . . X . X X X . . O . . X X X O O X . 6
5 . . . . . . . . X . O . X O X O X X . 5
4 . . . X . . . . . X . O . O X X O O . 4
3 . . . . . . . . . . X . O . O O X O . 3
2 . . . . . . . . . . . . . . . . . . . 2
1 . . . . . . . . . . . . . . . . . . . 1
  A B C D E F G H J K L M N O P Q R S T

Then I found that the semeai module only generates one move if it's a 
winning move. The attached patch will put all outside liberties of the 
opponent group under semeai on the move list if the semeai module thinks 
filling outside liberty can win the semeai. Self atari liberties will not be 
counted as candidate moves. Also if the result of semeai module is a ko or 
snap-back, only this move is a candidate.

After this patch, gnugo can play R12 in the above situation.

There are not many regression changes.

strategy.tst:45  FAIL: Correct 'G17|G18|C1', got 'H1'
strategy2.tst:80 PASS [S8]

For strategy:45 I think H1 is much better than C1, because if white doesn't 
play around the corner, black has the chance to avoid a ko, although it 
might look like a 10000 year ko. Therefore I also made a patch for 
strategy.tst.

SP Lee

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JYP.sgf
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SemeaiPatch
Description: Text document