#944 add automatic discretisation

pybamm/discretisations/discretisation.py

@@ -203,6 +203,9 @@ def process_model(self, model, inplace=True, check_model=True):
 
         pybamm.logger.info("Finish discretising {}".format(model.name))
 
+        # Record that the model has been discretised
+        model_disc.is_discretised = True
+
         return model_disc
 
     def set_variable_slices(self, variables):

pybamm/models/base_model.py

@@ -121,6 +121,9 @@ def __init__(self, name="Unnamed model"):
         self.use_simplify = True
         self.convert_to_format = "casadi"
 
+        # Model is not initially discretised
+        self.is_discretised = False
+
         # Default timescale is 1 second
         self.timescale = pybamm.Scalar(1)
 

pybamm/solvers/base_solver.py

@@ -128,6 +128,15 @@ def set_up(self, model, inputs=None):
             raise pybamm.SolverError(
                 """Cannot use algebraic solver to solve model with time derivatives"""
             )
+        # Discretise model if it isn't already discretised
+        # This only works with purely 0D models, as otherwise the mesh and spatial
+        # method should be specified by the user
+        if model.is_discretised is False:
+            disc = pybamm.Discretisation()
+            disc.process_model(model)
+            # try:
+            # except error as e:
+            #     raise ValueError(e)
 
         inputs = inputs or {}
         y0 = model.concatenated_initial_conditions.evaluate(0, None, inputs=inputs)
@@ -564,11 +573,7 @@ def solve(self, model, t_eval=None, external_variables=None, inputs=None):
         ]
 
         # remove any discontinuities after end of t_eval
-        discontinuities = [
-            v
-            for v in discontinuities
-            if v < t_eval_dimensionless[-1]
-        ]
+        discontinuities = [v for v in discontinuities if v < t_eval_dimensionless[-1]]
 
         if len(discontinuities) > 0:
             pybamm.logger.info(