Index: /trunk/psLib/src/math/psMixtureModels.c
===================================================================
--- /trunk/psLib/src/math/psMixtureModels.c	(revision 36427)
+++ /trunk/psLib/src/math/psMixtureModels.c	(revision 36428)
@@ -320,6 +320,8 @@
 	}
       }
-      i = modes->data.F32[k];
-      counts->data.F32[i] += 1.0;
+      if (modes->data.F32[k] != -1) {
+	i = modes->data.F32[k];
+	counts->data.F32[i] += 1.0;
+      }
     }
 
@@ -335,6 +337,8 @@
     for (k = 0; k < N; k++) {
       i = modes->data.F32[k];
-      for (j = 0; j < dim; j++) {
-	means->data.F32[i][j] += D->data.F32[k][j];
+      if (i != -1) {
+	for (j = 0; j < dim; j++) {
+	  means->data.F32[i][j] += D->data.F32[k][j];
+	}
       }
     }