Re: [gnugo-devel] Extremely bad mistake

[Gunnar Farneback]

SP Lee wrote:
> Sorry, I'm afraid my question was not so clear. I just want to ask
> when gnugo consider defense of a group, does it consider the liberties
> of surrounding opponent group? If yes, is it because there are now too
> many (4) liberties of the surrounding group?

Yes. Usually it's just a waste of time for a two-liberty string to
consider filling a liberty of a four-liberty neighbor.

The relevant code can be found in defend2 (trying to defend a
2-liberty string) and its calls to break_chain_moves (attack
surrounding strings with one liberty), break_chain2_moves (attack
surrounding strings with two liberties), and break_chain3_moves
(attack surrounding strings with three liberties). In this case we
would also need a break_chain4_moves, or better yet something to the
same effect which only applies in semeai-like situations.

/Gunnar