[gnugo-devel] attack_either ...

[alain Baeckeroot]

Hi

Example from the comment of attack_either  (now in ticket 147)

      3 |XOOOOOOOX|
      2 |XOXXOXXOX|
      1 |XX..a..XX|
        +---------+
         ABCDEFGHJ 

attack_either D2 F2
= 0

but, in combinations(), find_double_threats(color) gives:
 Double threat at E1, either C2 or F2 attacked.

So the moves génération says : 
  E1: 5.50 - either attacks C2 (5.50) or attacks F2 (5.50)
  E1: 2.05 - strategic effect on C9
  E1: 4.35 - strategic effect on H9
  E1:   0.00 - total followup value, added 0.00 as territorial followup
Move generation values E1 to 11.90

so it find the good move, for the good reason (even if stategic effect on H9
is somewhat overestimated ;)

Q1/ So, i wonder it "attack_either" and "defend_both" should not be moved into
patterns/helpers.c as they are used only for pattern matching.
Thus it would be more clear why not many things can be done, as not all data
are available yet. Or maybe add comment explaining this?

Q2/ i m a bit lost: attack_either is needed in some pattern match
so by shapes, but also before, by make_dragons ?
It seems that make worms provides attack points and threats, so i
wonder if attack_either could use find_double_threats for
better results ?

Alain