Abort on nan

src/navier-stokes.c

@@ -226,6 +226,12 @@ int enstrophy(
     alpha=compute_alpha(u, K1, K2, g, L);
     enstrophy=compute_enstrophy(u, K1, K2, L);
 
+    // check that anything is nan
+    if(isnan(alpha) || isnan(enstrophy)){
+      fprintf(stderr,"nan encountered, aborting.\n");
+      break;
+    }
+
     // add to running averages (estimate the total duration of interval as print_freq, will be adjusted later)
     avg_a+=alpha*(step/print_freq);
     avg_en+=enstrophy*(step/print_freq);