Re: [gnugo-devel] territory values

[Gunnar Farnebäck]

Arend wrote:
> Hmm. I think N13 should be considered safe territory even before
> scoring. So I guess fixing the territory evaluation would be better, if
> possible? 

I was sort of hoping that you would have a good idea how to approach
it. The patch below I think is good when scoring but I suppose it's
not appropriate otherwise.

> OTOH, the fate of W R17 or W R16 isn't _that_ clear...

Agreed. But I'd rather not have the scoring attempt such invasions,
even when instructed to finish the game before actually scoring.

/Gunnar

Index: engine/influence.c
===================================================================
RCS file: /cvsroot/gnugo/gnugo/engine/influence.c,v
retrieving revision 1.107
diff -u -r1.107 influence.c
--- engine/influence.c  6 Jan 2005 19:50:27 -0000       1.107
+++ engine/influence.c  17 Jan 2005 03:38:37 -0000
@@ -1456,6 +1456,20 @@
        /* If both side have small influence, we have to reduce this value.
         * What we consider "small influence" depends on how central this
         * intersection lies.
+        *
+        * The values of central on an 11x11 board become:
+        *
+        *  4  5  6  7  7  7  7  7  6  5  4
+        *  5  8  9 10 10 10 10 10  9  8  5
+        *  6  9 12 13 13 13 13 13 12  9  6
+        *  7 10 13 16 16 16 16 16 13 10  7
+        *  7 10 13 16 17 17 17 16 13 10  7
+        *  7 10 13 16 17 18 17 16 13 10  7
+        *  7 10 13 16 17 17 17 16 13 10  7
+        *  7 10 13 16 16 16 16 16 13 10  7
+        *  6  9 12 13 13 13 13 13 12  9  6
+        *  5  8  9 10 10 10 10 10  9  8  5
+        *  4  5  6  7  7  7  7  7  6  5  4
         */
         dist_i = gg_min(I(ii), board_size - I(ii) - 1);
         dist_j = gg_min(J(ii), board_size - J(ii) - 1);
@@ -1466,6 +1480,14 @@
        central = (float) 2 * gg_min(dist_i, dist_j) + dist_i + dist_j;
         ratio = gg_max(q->black_influence[ii], q->white_influence[ii])
                 / gg_interpolate(&min_infl_for_territory, central);
+
+       /* Do not make this adjustment when scoring unless both
+        * players have non-zero influence.
+        */
+       if (doing_scoring && (q->black_influence[ii] == 0.0
+                             || q->white_influence[ii] == 0.0))
+         ratio = 1.0;
+       
         first_guess[ii] *= gg_interpolate(&territory_correction, ratio);
 
        /* Dead stone, upgrade to territory. Notice that this is not