Re: [gnugo-devel] trevor_1_16.3 & trevor_1_16.4

[Gunnar Farneback]

Trevor wrote:
> The dragon status changed for these 3 dragons; I don't understand
> why this happened.  The result is that the mystic strategic effect
> changed.
> strategy2:66 FAILED 
>   #J11 dragon status changed from weak to alive...
> strategy3:119 FAILED 
>   #C6 dragon status changed from weakly alive to alive...
> trevor:15 FAILED 
>   # dragon A7 status changed from weakly alive to alive.

It might have had something to do with an owl_threaten_attack() or
owl_threaten_defense() result changing.

> Bad problem:
> owl:245 FAILED 
>   #K7 is also a valid defense.

Oops, not good. I think I'll modify this diagram by moving the O6
group one step to the right.

>From the patch:
>  #
>  # where X can play above * and get miai between capturing * and
>  # escaping through the gap towards the center.
> +
> +# tm modified (3.1.16)
> +#   addresses above concern, a bit.
>  
> -O.X         third line kosumi
> +???         third line kosumi
> +O.X
>  .*X
>  ...
>  ---
>  
>  :8,-,value(55)
>  
> +?C?
> +OAX
> +.*X
> +...
> +---
> +
> +; oplay_attack(*,A,*) && (owl_escape_value(C) > 0)
> +

Maybe I'm reading the patch wrong, but it seems like the constraint
fires exactly when this move is problematic. Maybe something should be
negated. On the other hand the owl_escape_value(C) will never be
positive because C is always as close as diagonal to the goal dragon.
See the owl_escape_value() function in owl.c. The reason for this
limitation is to avoid dragons "escaping" towards themselves.

> +Pattern D230
> +# tm New Pattern (3.1.16)
> +
> +OO...        expand along edge.
> +....*
> +.....
> +
> +:8,-,value(80)

No edge present.

/Gunnar