#570 update changelog and get it actually working

Author: valentinsulzer

CHANGELOG.md

@@ -16,6 +16,7 @@
 
 ## Bug fixes
 
+-   Add warning if `ProcessedVariable` is called outisde its interpolation range ([#681](https://github.com/pybamm-team/PyBaMM/pull/681))
 -   Improve the way `ProcessedVariable` objects are created in higher dimensions ([#581](https://github.com/pybamm-team/PyBaMM/pull/581))
 
 # [v0.1.0](https://github.com/pybamm-team/PyBaMM/tree/v0.1.0) - 2019-10-08

pybamm/processed_variable.py

@@ -404,9 +404,9 @@ def __call__(self, t=None, x=None, r=None, y=None, z=None, warn=True):
                 out = self.call_2D(t, x, r, z)
         elif self.dimensions == 3:
             out = self.call_3D(t, x, r, y, z)
-        if warn is True and out is None:
+        if warn is True and np.isnan(out).any():
             pybamm.logger.warning(
-                "Calling variable outside interpolation range (returns 'None')"
+                "Calling variable outside interpolation range (returns 'nan')"
             )
         return out