#704 updated as suggested by rob and tino

Author: Scottmar93

examples/scripts/compare_extrapolations.py

@@ -4,8 +4,6 @@
 x_n = pybamm.standard_spatial_vars.x_n
 x_s = pybamm.standard_spatial_vars.x_s
 x_p = pybamm.standard_spatial_vars.x_p
-r_n = pybamm.standard_spatial_vars.r_n
-r_p = pybamm.standard_spatial_vars.r_p
 
 var_pts = {x_n: 10, x_s: 3, x_p: 10}
 model_lin = pybamm.lead_acid.Full()

pybamm/discretisations/discretisation.py

@@ -28,8 +28,9 @@ class Discretisation(object):
     mesh : pybamm.Mesh
             contains all submeshes to be used on each domain
     spatial_methods : dict
-            a dictionary of the spatial method to be used on each
-            domain. The keys correspond to the keys in a pybamm.Model
+            a dictionary of the spatial methods to be used on each
+            domain. The keys correspond to the model domains and the
+            values to the spatial method.
     """
 
     def __init__(self, mesh=None, spatial_methods=None):

pybamm/spatial_methods/scikit_finite_element.py

@@ -334,9 +334,6 @@ def boundary_value_or_flux(self, symbol, discretised_child, bcs=None):
         Overwrites the default :meth:`pybamm.SpatialMethod.boundary_value`
         """
 
-        if bcs is None:
-            bcs = {}
-
         # Return average value on the negative tab for "negative tab" and positive tab
         # for "positive tab"
         if isinstance(symbol, pybamm.BoundaryValue):

pybamm/spatial_methods/spatial_method.py

@@ -305,8 +305,10 @@ def boundary_value_or_flux(self, symbol, discretised_child, bcs=None):
             The boundary value or flux symbol
         discretised_child : :class:`pybamm.StateVector`
             The discretised variable from which to calculate the boundary value
-        bcs : dict
-            The boundary conditions
+        bcs : dict (optional)
+            The boundary conditions. If these are supplied and "use bcs" is True in
+            the options, then these will be used to improve the accuracy of the
+            extrapolation.
 
         Returns
         -------