PropMap Bug fix with unmapped derivs.

SimPEG/PropMaps.py

@@ -68,7 +68,10 @@ class Property(object):
 
             if mapping is None and prop.propertyLink is not None:
                 linkName, linkMapClass = prop.propertyLink
-                linkMap = linkMapClass(None) * getattr(self, '%sMap'%linkName)
+                linkedMap = getattr(self, '%sMap'%linkName)
+                if linkedMap is None:
+                    return None
+                linkMap = linkMapClass(None) * linkedMap
                 m = getattr(self, '%s'%linkName)
                 return linkMap.deriv( m )
 

SimPEG/Tests/test_PropMaps.py

@@ -10,7 +10,8 @@ class MyPropMap(Maps.PropMap):
 class MyReciprocalPropMap(Maps.PropMap):
     sigma = Maps.Property("Electrical Conductivity", defaultInvProp=True, propertyLink=('rho',   Maps.ReciprocalMap))
     rho   = Maps.Property("Electrical Resistivity",                       propertyLink=('sigma', Maps.ReciprocalMap))
-    mu    = Maps.Property("Mu", defaultVal=mu_0)
+    mu    = Maps.Property("Mu", defaultVal=mu_0, propertyLink=('mui',   Maps.ReciprocalMap))
+    mui    = Maps.Property("Mu", defaultVal=1./mu_0, propertyLink=('mu',   Maps.ReciprocalMap))
 
 
 class TestPropMaps(unittest.TestCase):
@@ -102,6 +103,11 @@ class TestPropMaps(unittest.TestCase):
         assert pm.sigmaDeriv is not None
         assert pm.rhoDeriv is not None
 
+        assert pm.muMap is None
+        assert pm.muDeriv is None
+        assert pm.muiMap is None
+        assert pm.muiDeriv is None
+
         PM = MyReciprocalPropMap([('rho', iMap)])
         pm = PM(np.r_[1,2.,3])
         # print pm.sigma