Index: trunk/psLib/src/math/psMinimizePolyFit.c
===================================================================
--- trunk/psLib/src/math/psMinimizePolyFit.c	(revision 37515)
+++ trunk/psLib/src/math/psMinimizePolyFit.c	(revision 37516)
@@ -733,5 +733,5 @@
 	  // scaling,
 	  median_zero = true;
-	  if ((sigma == 1.0)||(sigma <= 0.0)) {
+	  if ((sigma == 1.0)||(fabs(sigma) <= 1e-10)) {
 	    // Don't bother scaling if sigma is unity (it's already scaled) or if the sigma calculation has gone wrong.
 	    scale = false;