Index: /issm/trunk/src/c/Orthx/Orthx.cpp
===================================================================
--- /issm/trunk/src/c/Orthx/Orthx.cpp	(revision 3518)
+++ /issm/trunk/src/c/Orthx/Orthx.cpp	(revision 3519)
@@ -27,4 +27,7 @@
 	/*scale to 1: gradient=gradient/max(abs(gradient))*/
 	VecNorm(newgradj,NORM_INFINITY,&norm_new);
+	if (norm_new<=0){
+		ISSMERROR("||∂J/∂α||∞ = 0  gradient is zero");
+	}
 	VecScale(newgradj,1.0/norm_new);