Mixins work differently than I thought, this fixes the DCProblem code.

SimPEG/forward/DCProblem.py

@@ -7,7 +7,7 @@ import numpy as np
 import scipy.sparse as sp
 import scipy.sparse.linalg as linalg
 
-class DCProblem(Problem, ModelTransforms.LogModel):
+class DCProblem(ModelTransforms.LogModel, Problem):
     """
         **DCProblem**
 

SimPEG/forward/ModelTransforms.py

@@ -1,5 +1,5 @@
 import numpy as np
-
+from SimPEG.utils import mkvc, sdiag
 
 class LogModel(object):
     """docstring for LogModel"""