[gnugo-devel] Influence patch

[Gunnar Farneback]

I've put up a patch at
http://www.lysator.liu.se/~gunnar/gnugo/patches/gunnar_1_14.7.gz

This patch makes some badly needed improvements to the influence code
and some tuning.

- non-territory patterns introduced in the influence code
- revised formula for addition of followup_value
- better trace output for followup_value and reverse_followup_value
- tuning
- owl tuning
- eye tuning
- influence tuning
- test case revisions

The main problem with the influence code that this patch solves is
that false eyes counted as territory, e.g. in this position

OOOXX
O..OX
OOOXX

O was thought to have two points of territory and after capture

OOOXX
O.X.X
OOOXX

X was thought to have one point of territory plus the captured stone,
making the capture valued to 4 points instead of 2.

Unfortunately it now thinks that all false eyes are worthless, so it
will undervalue moves like * here (X is assumed to be strongly alive
on both sides)

..O..
XXOXX
..*..
-----

This is not so easily solved though since it requires a detailed
analysis of the positions of eyes. For a good example, compare the
value of * with and without the x in place in this position

XXXOOOO....
X.XOOO.OO..
XX.XXO.O.OO
.XXX.XOOO.O
OOOOX.XO.OO
.O.OOX.XXOO
.OO.O*X...O
..OOO.XxXXO
....OO.O..O
.....OOOOOO

The patch is already in CVS.

/Gunnar