Index: /issm/trunk-jpl/src/m/classes/frontalforcings.py
===================================================================
--- /issm/trunk-jpl/src/m/classes/frontalforcings.py	(revision 27417)
+++ /issm/trunk-jpl/src/m/classes/frontalforcings.py	(revision 27418)
@@ -1,5 +1,7 @@
+import numpy as np
+
+from checkfield import checkfield
 from fielddisplay import fielddisplay
 from project3d import project3d
-from checkfield import checkfield
 from WriteData import WriteData
 
@@ -14,8 +16,15 @@
 
     def __init__(self):  # {{{
-        self.meltingrate = float('NaN')
-        self.ablationrate = float('NaN')
+        self.meltingrate = np.nan
+        self.ablationrate = np.nan
 
-        self.setdefaultparameters()
+        nargs = len(args)
+        if nargs == 0:
+            self.setdefaultparameters()
+        elif nargs == 1:
+            # TODO: Replace the following with constructor
+            self.setdefaultparameters()
+        else:
+            raise Exception('constructor not supported')
     #}}}
 
@@ -35,6 +44,6 @@
 
     def setdefaultparameters(self):  # {{{
-        self.meltingrate = float('NaN')
-        self.ablationrate = float('NaN')
+        self.meltingrate = np.nan
+        self.ablationrate = np.nan
         return self
     #}}}