[gnugo-devel] experimental connections patch

[Gunnar Farneback]

I've put up a patch at
http://www.lysator.liu.se/~gunnar/gnugo/patches/gunnar_3_3.9

Contingent on experimental_connections, this patch revises the
amalgamation scheme. Most importantly no amalgamation is made around
eye spaces. The connections in conn.db are still used, but a new set
of patterns with readconnect constraints are used. For old and new
patterns to coexist, the Y classification is used for patterns which
only apply for experimental connections and the W classification for
standard connections.

Notice that this is only a partial reimplementation of the dragon
amalgamation scheme. It does not give a robust solution to the
intransitivity problems, but it should be able to reduce it. In
particular there are no modifications to the dragon data structures,
only which amalgamations are made changes.

I have not added the patch to CVS yet. Presumably the patch should
have only small effects with standard connections, but the regressions
seemed to run unusually slow, so I'm not entirely sure there aren't
any problems. It would be good if someone else could check this.

With experimental connections the engine may well be slower (mainly
because it overamalgamates less, so that there are more dragons around
to do owl reading for) and possibly weaker since the new connection
patterns aren't fully tuned. This is currently being tested on NNGS,
so if GNU Go behaves unusually there, this is why. I don't have
current regression results, but from earlier runs I know those should
be favorable with experimental connections.

- no amalgamation around eye spaces with experimental_connections enabled
- eye spaces no longer modified by INHIBIT_CONNECTION with
  experimental_connections enabled
- bugfix in find_connection_moves()
- pattern classes Y and W introduced in conn.db to identify patterns
  which only applies with or without experimental_connections
- patterns with class e in conn.db changed to class I to better
  reflect current usage
- connection tuning

/Gunnar