Re: [gnugo-devel] Owl patterns

[Gunnar Farneback]

Dan wrote:
> As for going through the patterns and deciding which ones have
> definite eye-making purpose, one approach would be to assume
> that they ALL do EXCEPT for those having to do with escape, to
> start with the D13xx patterns. So I think the D13xx patterns
> would be a good start on such a list. Let us call them escape
> patterns.

Most of the D3xx patterns have a distinct escape flavor too.

> I would propose that a parameter is passed during reading
> which counts the number of calls to escape patterns in
> higher nodes of the tree. This parameter is incremented
> when an escape pattern is. (This escape pattern count
> would have to be added to the cached data.) 

Although the cache space is a limited resource, we do at least have
the result2 (4 bits) and str2 (10 bits) areas of the cache data to our
disposal, since the owl reading only concerns itself with one dragon.
It may be more difficult if we want to use this also for the semeai
code, though.

> If this number exceeds a small constant, perhaps about
> two, then calls to owl_determine_life are not made. Thus
> once the dragon embarks on an escape it has to continue to
> escape, rather than trying to make eyes. Allowing one or
> two exceptions would help in situations where the dragon
> can make an eye by threatening to escape.

Or we could still run owl_determine_life() but only allow eye making
moves if that would immediately bring us up to two eyes.

/Gunnar