Re: [gnugo-devel] Floating point exception in influence.c

[Arend Bayer]

Thanks for your quick report, that was my fault of course. Rrgs, I still
hope I will get less careless sometimes. The patch below should fix the
problem.

> When compiling gnugo-3.1.23 with experimental influence turned on I get
> a floating point exception at
> line 1161 of influence.c if I launch gnugo with gnugo --color white.
I did not know the influence function gets called with the empty
board in this case. Is this different from gmp mode?

Arend

arend_1_24.1: experimental influence: floating point exception cure


Index: engine/influence.c
===================================================================
RCS file: /cvsroot/gnugo/gnugo/engine/influence.c,v
retrieving revision 1.31
diff -u -r1.31 influence.c
--- engine/influence.c  28 Jan 2002 18:29:31 -0000      1.31
+++ engine/influence.c  29 Jan 2002 14:50:33 -0000
@@ -1158,8 +1189,10 @@
 
       if (q->p[i][j] == EMPTY
          || (q->black_strength[i][j] == 0 && q->white_strength[i][j] == 0)) {
-        float diff = ( q->white_influence[i][j] - q->black_influence[i][j] )
-                    /( q->white_influence[i][j] + q->black_influence[i][j] );
+        float diff = 0.0;
+        if (q->white_influence[i][j] + q->black_influence[i][j] > 0)
+          diff = (q->white_influence[i][j] - q->black_influence[i][j])
+                /(q->white_influence[i][j] + q->black_influence[i][j]);
         first_guess[i][j] = diff * diff * diff;
         first_guess[i][j] *= interpolate(&territory_correction,
                                          gg_max(q->black_influence[i][j],