Re: [gnugo-devel] atari_atari patch

[Gunnar Farneback]

Evan wrote:
> OK, I'll work on that.  Defending tactically critical enclosing strings
> made sense to me as a general thing, but I think you're right that it will
> help with speed.

I don't think it really makes sense generally. To begin with we don't
want to include uninteresting tactical defenses like filling an
unimportant ko or saving a small string without strategical
importance. This could to some extent be helped by excluding strings
which were tactically unstable at the start of the atari_atari
reading. The second problem is that tactical defenses fairly often
are not strategically viable, reaching five liberties but no potential
for eyes. Especially stones played in the atari_atari attack sequence
can often be saved tactically without gaining life, unless a
substantial opponent string is captured in the process.

> Oops, looks like I forgot to remove those once it worked.  Oh, is
> 
> for (k = BOARDMIN; k < BOARDMAX; k++) {
>   if (k != find_origin(k))
>     continue;
> 
> the recommended way to loop over all strings?

No, find_origin() is only valid to call for stones. The usual
formulation would be

  for (k = BOARDMIN; k < BOARDMAX; k++) {
    if (!IS_STONE(board[k]) || k != find_origin(k))
      continue;

/Gunnar