Base Submodel

class pybamm.BaseSubModel(param, domain=None, name='Unnamed submodel', external=False, options=None)

The base class for all submodels. All submodels inherit from this class and must only provide public methods which overwrite those in this base class. Any methods added to a submodel that do not overwrite those in this bass class are made private with the prefix ‘_’, providing a consistent public interface for all submodels.

Parameters

param (parameter class) – The model parameter symbols

param

The model parameter symbols

Type

parameter class

rhs

A dictionary that maps expressions (variables) to expressions that represent the rhs

Type

dict

algebraic

A dictionary that maps expressions (variables) to expressions that represent the algebraic equations. The algebraic expressions are assumed to equate to zero. Note that all the variables in the model must exist in the keys of rhs or algebraic.

Type

dict

initial_conditions

A dictionary that maps expressions (variables) to expressions that represent the initial conditions for the state variables y. The initial conditions for algebraic variables are provided as initial guesses to a root finding algorithm that calculates consistent initial conditions.

Type

dict

boundary_conditions

A dictionary that maps expressions (variables) to expressions that represent the boundary conditions

Type

dict

variables

A dictionary that maps strings to expressions that represent the useful variables

Type

dict

events

A list of events. Each event can either cause the solver to terminate (e.g. concentration goes negative), or be used to inform the solver of the existance of a discontinuity (e.g. discontinuity in the input current)

Type

list

get_coupled_variables(variables)

A public method that creates and returns the variables in a submodel which require variables in other submodels to be set first. For example, the exchange current density requires the concentration in the electrolyte to be created before it can be created. If a variable can be created independent of other submodels then it should be created in ‘get_fundamental_variables’ instead of this method.

Parameters

variables (dict) – The variables in the whole model.

Returns

The variables created in this submodel which depend on variables in other submodels.

Return type

dict

get_external_variables()

A public method that returns the variables in a submodel which are supplied by an external source.

Returns

A list of the external variables in the model.

Return type

list

get_fundamental_variables()

A public method that creates and returns the variables in a submodel which can be created independent of other submodels. For example, the electrolyte concentration variables can be created independent of whether any other variables have been defined in the model. As a rule, if a variable can be created without variables from other submodels, then it should be placed in this method.

Returns

The variables created by the submodel which are independent of variables in other submodels.

Return type

dict

set_algebraic(variables)

A method to set the differential equations which do not contain a time derivative. Note: this method modifies the state of self.algebraic. Unless overwritten by a submodel, the default behaviour of ‘pass’ is used as implemented in pybamm.BaseSubModel.

Parameters

variables (dict) – The variables in the whole model.

set_boundary_conditions(variables)

A method to set the boundary conditions for the submodel. Note: this method modifies the state of self.boundary_conditions. Unless overwritten by a submodel, the default behaviour of ‘pass’ is used a implemented in pybamm.BaseSubModel.

Parameters

variables (dict) – The variables in the whole model.

set_events(variables)

A method to set events related to the state of submodel variable. Note: this method modifies the state of self.events. Unless overwritten by a submodel, the default behaviour of ‘pass’ is used a implemented in pybamm.BaseSubModel.

Parameters

variables (dict) – The variables in the whole model.

set_initial_conditions(variables)

A method to set the initial conditions for the submodel. Note: this method modifies the state of self.initial_conditions. Unless overwritten by a submodel, the default behaviour of ‘pass’ is used a implemented in pybamm.BaseSubModel.

Parameters

variables (dict) – The variables in the whole model.

set_rhs(variables)

A method to set the right hand side of the differential equations which contain a time derivative. Note: this method modifies the state of self.rhs. Unless overwritten by a submodel, the default behaviour of ‘pass’ is used as implemented in pybamm.BaseSubModel.

Parameters

variables (dict) – The variables in the whole model.