Re: [gnugo-devel] look at regress file 13x13b:6

[kevin yong]

Hi, Evan:
  I did some work on 13x13:74.
  Problem: gnugo should move at G10, not G7.
  From the ‘show_dragons()’ report, I notice that
there is no attack/defend point produce either for
worm G11 at make_worms() stage, or for dragon J12
(including worm G11) at make_dragons() stage.
Especially, not identify G10 as such a point for worm
G11 or for dragon J12. I think it’s hard to say there
is something much wrong with these, because worm
G11/dragon J12 is NOT under threat.
Of cause, shapes() analysis recoganized G10 as
strategic effects on dragon M12, and some values
assigned to it. I think it’s hard to say there is
something much wrong with these either.
My point is: the issue for this case is not about
something wrong with the current code, but about need
to add another new section of analysis. This new
analysis is: gnugo needs think at least one more step
deep.
What I mean is: currently, gnugo only think what’s the
best move for the current-color (of course, with some
multi-step reading regarding this move), without
thinking what’s the next best move for the
opponent-color;

  I did another test: after B move at G7 (step 33), I
let gnugo think for W move step 34. It choose F5. it
did not give value to G10.

As human player, why do we think G10 is move value
than G7? Because if B move at G7, W will move G10, and
have fairly good chance to break through. If B do move
at G10, then it secure the situation.

So, regarding this specific case, gnugo need
improvements on two fronts:
1.      as if it think for W to move step-34, it should
choose G10 (that’s originally why we think G10 is
important for B to move);
2.      so, at the stage when gnugo think for B to move
step-33, it should look at one step deeper: what’s the
next best move for W, if B move at G7. it should found
B would best move at G10, and may break through. Then
prune back to step-33 the best move for B is also G10.

kevin.



______________________________________________________________________ 
Post your free ad now! http://personals.yahoo.ca