Re: [gnugo-devel] success!

[Gunnar Farneback]

Evan wrote:
> OK, I've got a game with two instances of illegal state changes (ALIVE ->
> DEAD and DEAD -> ALIVE).  sgf file follows, at moves 135 (group P11 goes
> from alive to dead) and 140 (group R16 goes from dead to alive).
> 
> The P11 group looks like it may be an artifact of dragons combining and
> being cut, but the R16 one looks very real.

Those are both real ones.

The next step when these mistakes are found is to make regression
tests of them. Those would best be owl tests, like

loadsgf xxx.sgf 139
1 owl_defend R16
#? [1 (O11|T15|T13)]

Unfortunately this requires some manual work and ability to read out
the position (but it's good exercise to find out which of the
inconsistent owl results is wrong). An alternative would be to have
some function to just check the consistency, similar to

loadsgf xxx.sgf 139
1 owl_consistency R16 W O11
#? [1]

where the imagined function owl_consistency would evaluate the owl
status of R16 before and after the white move at O11 and check for
invalid changes. Such regression tests should in principle be possible
to generate automatically.

/Gunnar