Re: [gnugo-devel] new to the engine and curious

[Evan Berggren Daniel]

On Sat, 27 Dec 2003, SP LEE wrote:

> I don't understand this situation very well, but I have tried using the
> command "connect D3 H1" and gnugo got the right answer F3. The command
> "defend D3" doesn't give the correct answer of course because that portion
> of gnugo doesn't use any pattern to make an escape, am I right?

F3 is a tactical defense of D3.  This can be confirmed by
trymove white F3
=

attack D3
= 0

The position is simple enough that it would be nice if the tactical
reading code tried the relevant move.

>
> By the way, the pure value of this connection is about 8 points, so it's
> possible that gnugo chooses other (bigger) positions to play.

That's not the reason this is important; the move is found by the
connection and owl code, and is probably valued reasonably.  The problem
is that in deep reading the tactics code is what is mainly used for
questions like that, and if the D3 stones matter for eg an owl pattern,
then a lot of things may depend on the reading code finding the answer.

Tactical constraints are used a lot in things like the owl code and the
atari-atari code for pattern matching; it can help both in getting correct
answers and in not trying extraneous moves with (expensive) owl nodes if
the reading code can find moves like this.

Evan Daniel