Index: /issm/trunk-jpl/src/m/classes/flowequation.py
===================================================================
--- /issm/trunk-jpl/src/m/classes/flowequation.py	(revision 20287)
+++ /issm/trunk-jpl/src/m/classes/flowequation.py	(revision 20288)
@@ -139,5 +139,6 @@
 		#convert approximations to enums
 		data=copy.deepcopy(self.vertex_equation); 
-		if numpy.isnan(data)==0:
+
+		if isinstance(data, (list, tuple, numpy.ndarray)):
 			data[numpy.nonzero(data==0)]=NoneApproximationEnum()
 			data[numpy.nonzero(data==1)]=SIAApproximationEnum()
@@ -151,5 +152,5 @@
 		WriteData(fid,'data',data,'enum',FlowequationVertexEquationEnum(),'format','DoubleMat','mattype',1)
 		data=copy.deepcopy(self.element_equation)
-		if numpy.isnan(data)==0:
+		if isinstance(data, (list, tuple, numpy.ndarray)):
 			data[numpy.nonzero(data==0)]=NoneApproximationEnum()
 			data[numpy.nonzero(data==1)]=SIAApproximationEnum()
Index: /issm/trunk-jpl/src/m/classes/stressbalance.py
===================================================================
--- /issm/trunk-jpl/src/m/classes/stressbalance.py	(revision 20287)
+++ /issm/trunk-jpl/src/m/classes/stressbalance.py	(revision 20288)
@@ -194,11 +194,11 @@
 		WriteData(fid,'object',self,'class','stressbalance','fieldname','rift_penalty_threshold','format','Integer')
 		WriteData(fid,'object',self,'class','stressbalance','fieldname','referential','format','DoubleMat','mattype',1)
-
-		if numpy.isnan(self.loadingforce):
-			lx=float('NaN'); ly=float('NaN'); lz=float('NaN');
-		else:
+		
+		if isinstance(self.loadingforce, (list, tuple, numpy.ndarray)):
 			lx=self.loadingforce[:,0];
 			ly=self.loadingforce[:,1];
 			lz=self.loadingforce[:,2];
+		else:
+			lx=float('NaN'); ly=float('NaN'); lz=float('NaN');
 
 		WriteData(fid,'data',lx,'format','DoubleMat','mattype',1,'enum',LoadingforceXEnum())