From b5b8b5fae68ae74109ffc91d6d793d929844506e Mon Sep 17 00:00:00 2001
From: Lindsey Heagy <lheagy@eos.ubc.ca>
Date: Sun, 5 Jul 2015 21:58:14 -0500
Subject: [PATCH] - added check is S_e is zero in getRHSDeriv of FDEM.py -
 deleted code that has been commented out

---
 simpegEM/FDEM/FDEM.py       | 31 +++++++++++++++++++++----------
 simpegEM/FDEM/FieldsFDEM.py |  4 ----
 2 files changed, 21 insertions(+), 14 deletions(-)

diff --git a/simpegEM/FDEM/FDEM.py b/simpegEM/FDEM/FDEM.py
index dde77f15..c54137fd 100644
--- a/simpegEM/FDEM/FDEM.py
+++ b/simpegEM/FDEM/FDEM.py
@@ -354,8 +354,9 @@ class ProblemFDEM_b(BaseFDEMProblem):
         elif SrcDeriv is not None:
             RHSderiv = SrcDeriv
 
-        if self._makeASymmetric is True and not adjoint:
-            return MfMui.T * RHSderiv
+        if RHSderiv is not None: 
+            if self._makeASymmetric is True and not adjoint:
+                return MfMui.T * RHSderiv
 
         return RHSderiv
 
@@ -576,20 +577,30 @@ class ProblemFDEM_h(BaseFDEMProblem):
         _, S_e = src.eval(self)
         C = self.mesh.edgeCurl
         MfRho  = self.MfRho
-        MfRhoDeriv = self.MfRhoDeriv(S_e)
-        S_mDeriv, S_eDeriv = src.evalDeriv(self, adjoint)
 
-        if not adjoint:
-            RHSDeriv = C.T * (MfRhoDeriv * v)
-        elif adjoint:
-            RHSDeriv = MfRhoDeriv.T * (C * v)
+        RHSDeriv = None
+
+        if S_e is not None:
+            MfRhoDeriv = self.MfRhoDeriv(S_e)
+            if not adjoint:
+                RHSDeriv = C.T * (MfRhoDeriv * v)
+            elif adjoint:
+                RHSDeriv = MfRhoDeriv.T * (C * v)
+
+        S_mDeriv, S_eDeriv = src.evalDeriv(self, adjoint)
 
         S_mDeriv = S_mDeriv(v)
         S_eDeriv = S_eDeriv(v)
         if S_mDeriv is not None:
-            RHSDeriv += S_mDeriv(v)
+            if RHSDeriv is not None: 
+                RHSDeriv += S_mDeriv(v)
+            else: 
+                RHSDeriv = S_mDeriv(v)
         if S_eDeriv is not None:
-            RHSDeriv += C.T * (MfRho * S_e)
+            if RHSDeriv is not None: 
+                RHSDeriv += C.T * (MfRho * S_e)
+            else:
+                RHSDeriv = C.T * (MfRho * S_e)
 
         return RHSDeriv
 
diff --git a/simpegEM/FDEM/FieldsFDEM.py b/simpegEM/FDEM/FieldsFDEM.py
index 46b67fa7..99866bc3 100644
--- a/simpegEM/FDEM/FieldsFDEM.py
+++ b/simpegEM/FDEM/FieldsFDEM.py
@@ -25,10 +25,6 @@ class FieldsFDEM_e(FieldsFDEM):
         self.prob = self.survey.prob
         self._edgeCurl = self.survey.prob.mesh.edgeCurl
 
-    # def getDeriv_u(self, fieldsList, src, v, adjoint=False):
-
-    # def getDeriv_m(self, fieldsList, src, v, adjoint=False):
-
     def _ePrimary(self, eSolution, srcList):
         ePrimary = np.zeros_like(eSolution)
         for i, src in enumerate(srcList):