[gnugo-devel] pattern classes b and e

[Gunnar Farneback]

A long time ago when I started implementing the current move
generation scheme, I thought it would be useful to distinguish between
"block territory" and "expand territory" move reasons. At the
beginning I think the valuation of those actually was different, but
ever since the responsibility for computing territorial values was
passed to the influence code, and probably before, there has been no
difference at all between them. As a matter of fact, the significance
of those move reasons today is in practice a statement that the move
is tactically and strategically safe. Incidentally the same holds for
the expand moyo move reason.

I intend to clean away the distinction between the block territory
(pattern class b) and expand territory (pattern class e) move reasons.
In practice this will mean reclassifying all b patterns in
patterns.db, patterns2.db, endgame.db, and fuseki.db to e patterns,
followed by removing the block territory move reason.

The patch
http://www.lysator.liu.se/~gunnar/gnugo/patches/gunnar_3_2.5.gz
does the first step, plus some other move reason and pattern cleanups,
namely:
* The functions compute_shape_factor(), move_connects_strings(), and
  move_reasons_confirm_safety() are moved from move_reasons.c to
  value_moves.c since that's the more logical place for them. The
  latter function also changes name to value_moves_confirm_safety().
* The pattern classification strings in the pattern databases are
  consistently ordered, e.g. instead of having "BO" classification at
  some places and "OB" classification at others, they are all called
  "OB" now. (Since I wrote a script for changing "b" or "be" to "e", I
  took the opportunity to do this cleanup as well.)

- compute_shape_factor() and move_connects_strings() moved from
  move_reasons.c to value_moves.c
- move_reasons_confirm_safety() moved likewise and renamed to
  value_moves_confirm_safety()
- b patterns in endgame.db, fuseki.db, patterns.db, and patterns2.db
  changed to e patterns
- classification letters ordered consistently in pattern databases

/Gunnar