#692 structure for external variables in place but need to debug

pybamm/discretisations/discretisation.py

@@ -150,7 +150,10 @@ def process_model(self, model, inplace=True):
             elif isinstance(var, pybamm.Variable):
                 start_vals += [self.y_slices[var.id][0].start]
 
-        self.external_start = min(start_vals)
+        model_disc.external_variables = model.external_variables
+        model_disc.external_start = min(start_vals)
+        model_disc.y_length = self.y_length
+        model_disc.y_slices = self.y_slices
 
         pybamm.logger.info("Discretise initial conditions for {}".format(model.name))
         ics, concat_ics = self.process_initial_conditions(model)

pybamm/simulation.py

@@ -134,7 +134,9 @@ def step(self, dt, solver=None, external_variables=None):
         if solver is None:
             solver = self.solver
 
-        self._solution = solver.step(self.built_model, dt, external_variables)
+        self._solution = solver.step(
+            self.built_model, dt, external_variables=external_variables
+        )
 
     def plot(self, quick_plot_vars=None):
         """

pybamm/solvers/base_solver.py

@@ -22,6 +22,9 @@ def __init__(self, method=None, rtol=1e-6, atol=1e-6):
         self._atol = atol
         self.name = "Base solver"
 
+        self.y_pad = None
+        self.y_ext = None
+
     @property
     def method(self):
         return self._method
@@ -147,9 +150,16 @@ def step(self, model, dt, npts=2, log=True, external_variables=None):
                 self.set_up(model)
             self.t = 0.0
             set_up_time = timer.time()
+
+            # create a y_pad vector of the correct size:
+            self.y_pad = np.zeros((model.external_start))
+
         else:
             set_up_time = None
 
+        if external_variables is None:
+            external_variables = {}
+
         # load external variables into a state vector
         self.y_ext = np.zeros((model.y_length, 1))
         for var_name, var_vals in external_variables.items():
@@ -193,6 +203,15 @@ def step(self, model, dt, npts=2, log=True, external_variables=None):
             )
         return solution
 
+    def add_external(self, y):
+        """
+        Pad the state vector and then add the external variables so that
+        it is of the correct shape for evaluate
+        """
+        if self.y_pad and self.y_ext:
+            y = np.concatenate(y, self.y_pad) + self.y_ext
+        return y
+
     def compute_solution(self, model, t_eval):
         """Calculate the solution of the model at specified times. Note: this
         does *not* execute the solver setup.

pybamm/solvers/dae_solver.py

@@ -188,6 +188,7 @@ def residuals(t, y, ydot):
             pybamm.logger.debug(
                 "Evaluating residuals for {} at t={}".format(model.name, t)
             )
+            y = self.add_external(y)
             y = y[:, np.newaxis]
             rhs_eval, known_evals = concatenated_rhs.evaluate(t, y, known_evals={})
             # reuse known_evals
@@ -202,6 +203,7 @@ def residuals(t, y, ydot):
         # Create event-dependent function to evaluate events
         def event_fun(event):
             def eval_event(t, y):
+                y = self.add_external(y)
                 return event.evaluate(t, y)
 
             return eval_event

pybamm/solvers/ode_solver.py

@@ -121,13 +121,15 @@ def set_up(self, model):
         # Create function to evaluate rhs
         def dydt(t, y):
             pybamm.logger.debug("Evaluating RHS for {} at t={}".format(model.name, t))
+            y = self.add_external(y)
             y = y[:, np.newaxis]
             dy = concatenated_rhs.evaluate(t, y, known_evals={})[0]
             return dy[:, 0]
 
         # Create event-dependent function to evaluate events
         def event_fun(event):
             def eval_event(t, y):
+                y = self.add_external(y)
                 return event.evaluate(t, y)
 
             return eval_event
@@ -138,6 +140,7 @@ def eval_event(t, y):
         if jac_rhs is not None:
 
             def jacobian(t, y):
+                y = self.add_external(y)
                 return jac_rhs.evaluate(t, y, known_evals={})[0]
 
         else:
@@ -193,6 +196,7 @@ def set_up_casadi(self, model):
 
         def dydt(t, y):
             pybamm.logger.debug("Evaluating RHS for {} at t={}".format(model.name, t))
+            y = self.add_external(y)
             dy = concatenated_rhs_fn(t, y).full()
             return dy[:, 0]
 
@@ -201,6 +205,7 @@ def event_fun(event):
             casadi_event_fn = casadi.Function("event", [t_casadi, y_casadi], [event])
 
             def eval_event(t, y):
+                y = self.add_external(y)
                 return casadi_event_fn(t, y)
 
             return eval_event
@@ -216,6 +221,7 @@ def eval_event(t, y):
             )
 
             def jacobian(t, y):
+                y = self.add_external(y)
                 return casadi_jac_fn(t, y)
 
         else:

tests/integration/test_models/test_full_battery_models/test_lithium_ion/test_use_external_submodel.py

@@ -35,10 +35,11 @@ def test_external_temperature(self):
 
         t_eval = np.linspace(0, 0.17, 100)
 
-        for t in t_eval:
+        for i, t in enumerate(t_eval):
+            dt = t_eval[i + 1] - t_eval[i]
             T = np.zeros((tot_pts, 1))
             external_variables = {"Cell temperature": T}
-            sim.step(external_variables=external_variables)
+            sim.step(dt, external_variables=external_variables)
 
 
 if __name__ == "__main__":