#692 added an get_external_variables method to submodels

pybamm/models/full_battery_models/base_battery_model.py

@@ -416,6 +416,19 @@ def build_model(self):
             )
             self.variables.update(submodel.get_fundamental_variables())
 
+        # Get any external variables
+        self.external_variables = []
+        for submodel_name, submodel in self.submodels.items():
+            pybamm.logger.debug(
+                "Getting external variables for {} submodel ({})".format(
+                    submodel_name, self.name
+                )
+            )
+            variables, external_variables = submodel.get_external_variables()
+
+            self.variables.update(variables)
+            self.external_variables += external_variables
+
         # Get coupled variables
         # Note: pybamm will try to get the coupled variables for the submodels in the
         # order they are set by the user. If this fails for a particular submodel,
@@ -454,6 +467,7 @@ def build_model(self):
             pybamm.logger.debug(
                 "Setting rhs for {} submodel ({})".format(submodel_name, self.name)
             )
+
             submodel.set_rhs(self.variables)
             pybamm.logger.debug(
                 "Setting algebraic for {} submodel ({})".format(

pybamm/models/submodels/base_submodel.py

@@ -101,6 +101,21 @@ def get_fundamental_variables(self):
         """
         return {}
 
+    def set_external_variables(self):
+        """
+        A public method that creates and returns the variables in a submodel which are
+        suppled external to the model.
+
+        Returns
+        -------
+        dict :
+            The variables created by the submodel which are independent of variables in
+            other submodels.
+        list :
+            A list of the external variables in the model.
+        """
+        return {}, []
+
     def get_coupled_variables(self, variables):
         """
         A public method that creates and returns the variables in a submodel which

pybamm/models/submodels/thermal/external/full.py

@@ -0,0 +1,32 @@
+#
+# A class for full external thermal models
+#
+import pybamm
+
+from ..base_thermal import BaseThermal
+
+
+class Full(BaseThermal):
+    """Class to link full external thermal submodels.
+
+    Parameters
+    ----------
+    param : parameter class
+        The parameters to use for this submodel
+
+
+    **Extends:** :class:`pybamm.thermal.BaseModel`
+    """
+
+    def __init__(self, param):
+        super().__init__(param)
+
+    def get_external_variables(self):
+        T = pybamm.standard_variables.T
+        T_cn = pybamm.BoundaryValue(T, "left")
+        T_cp = pybamm.BoundaryValue(T, "right")
+
+        variables = self._get_standard_fundamental_variables(T, T_cn, T_cp)
+        external_variables = [T]
+
+        return variables, external_variables

pybamm/models/submodels/thermal/external/lumped.py

@@ -0,0 +1,39 @@
+#
+# A class for external lumped thermal models
+#
+import pybamm
+
+from ..base_thermal import BaseThermal
+
+
+class Full(BaseThermal):
+    """Class to link external lumped thermal submodels.
+
+    Parameters
+    ----------
+    param : parameter class
+        The parameters to use for this submodel
+
+
+    **Extends:** :class:`pybamm.thermal.BaseModel`
+    """
+
+    def __init__(self, param):
+        super().__init__(param)
+
+    def get_external_variables(self):
+        T_x_av = pybamm.standard_variables.T_av
+        T_n = pybamm.PrimaryBroadcast(T_x_av, "negative electrode")
+        T_s = pybamm.PrimaryBroadcast(T_x_av, "separator")
+        T_p = pybamm.PrimaryBroadcast(T_x_av, "positive electrode")
+        T = pybamm.Concatenation(T_n, T_s, T_p)
+
+        T_cn = T_x_av
+        T_cp = T_x_av
+
+        variables = self._get_standard_fundamental_variables(T, T_cn, T_cp)
+        variables = self._get_standard_fundamental_variables(T, T_cn, T_cp)
+
+        external_variables = [T_x_av]
+
+        return variables, external_variables