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Re: Re[2]: [gnugo-devel] life & death (3.3.5)
From: |
Gunnar Farneback |
Subject: |
Re: Re[2]: [gnugo-devel] life & death (3.3.5) |
Date: |
Wed, 28 Aug 2002 22:44:14 +0200 |
User-agent: |
EMH/1.14.1 SEMI/1.14.3 (Ushinoya) FLIM/1.14.2 (Yagi-Nishiguchi) APEL/10.3 Emacs/20.7 (sparc-sun-solaris2.7) (with unibyte mode) |
Paul wrote:
> - eye-space analyzing in life.c and optics.c doesn't consider the
You can safely ignore the code in life.c. It is not in use and is
likely to be removed sometime soon.
> fact that strings at A4 and at C7 (as well as at A8 and at C7)
> are not connected. linear five vertices eye shape is considered
> to give 2 eyes unconditionally (per eyes.db).
Correct, the eye analysis doesn't have the concept of cutting points.
> - owl reading doesn't go deep enough to find that A5 is a critical
> point.
It's not really a question of depth but rather that it doesn't
understand that the move is worth investigating.
> i think we could implement the following concept:
> - list all the strings the dragon consists of (A8, C7, A4).
This step is easy. :-)
> - check if they are connectable with moves outside eye shape (A8 and
> C7 can be connected by C8, A4 and C7 cannot be connected).
This is not trivial, in the sense that we don't have a machinery in
place for this analysis.
> - separate the dragon into parts which must be connected (in case
> of attack) with moves inside eye shape (2 parts A8+C7 and A4).
This is not clear. If black attacks at C8, doesn't white have to
connect A8 and C7 inside the eye space as well?
> - enumerate common liberties/connections of different parts (here
> goes the vague part) - parts can be "connected" by A5 or B5.
Indeed, this is quite vague.
> - note that black A5 forces us to play B5 sooner or later (black
> can just make atari).
This is kind of a key point, but how do we carry out the analysis
leading to the conclusion?
> [...]
> well, this is an intricate explanation, but i think i managed to
> formulate the main idea. maybe it would allow to impove life & death
> code somewhat.
It's a good start, even though it probably needs a lot of refinement.
In any case this is an important problem to solve.
/Gunnar