Re: [gnugo-devel] Revision of trevor_3_11.1

[Trevor Morris]

>
>+ Pattern A1119
>+ # same as A1119; different anchor.
>+ 
>+ X*?       cut off escape route.
>+ o.Y
>+ 
>+ :8,n,value(36)
>+ 
>+ a*E
>+ Dcb
>+ 
>+ ;(owl_escape_value(a)>0 || owl_escape_value(b)>0)
>+ ;&& ((o_somewhere(E) || x_somewhere(E)) || owl_escape_value(a) < 0)
>+ ;&& !oplay_attack_either(*,c,D,*,D)
>+ 
>+
>
>Why?
>
>I didn't use this piece because I didn't understand how
>duplicating the pattern with a different anchor is a 
>good idea.

It should've been named Pattern A1119a

The reason for duplicating some of the patterns is because, for example,
in the pattern above, a & b may either be in the goal, but both are not
guaranteed to be in the dragon.

The whole point of adding explicit anchors is that the anchors are only
matched against the goal, so we'd miss half of the good matches for this
pattern if we don't duplicate it with both a & b as anchors.

(I'm looking at the compile errors for trevor_3_11.1a now...)

-Trevor