#include <deal.II/base/function.h>

Inheritance diagram for ConstantFunction< dim, Number >:

Public Member Functions
	ConstantFunction (const Number value, const unsigned int n_components=1)

	ConstantFunction (const std::vector< Number > &values)

	ConstantFunction (const Vector< Number > &values)

	ConstantFunction (const Number *begin_ptr, const unsigned int n_components)

virtual	~ConstantFunction ()

virtual Number	value (const Point< dim > &p, const unsigned int component) const

virtual void	vector_value (const Point< dim > &p, Vector< Number > &return_value) const

virtual void	value_list (const std::vector< Point< dim > > &points, std::vector< Number > &return_values, const unsigned int component=0) const

virtual void	vector_value_list (const std::vector< Point< dim > > &points, std::vector< Vector< Number > > &return_values) const

Public Member Functions inherited from ZeroFunction< dim, Number >
	ZeroFunction (const unsigned int n_components=1)

virtual	~ZeroFunction ()

virtual Tensor< 1, dim, Number >	gradient (const Point< dim > &p, const unsigned int component=0) const

virtual void	vector_gradient (const Point< dim > &p, std::vector< Tensor< 1, dim, Number > > &gradients) const

virtual void	gradient_list (const std::vector< Point< dim > > &points, std::vector< Tensor< 1, dim, Number > > &gradients, const unsigned int component=0) const

virtual void	vector_gradient_list (const std::vector< Point< dim > > &points, std::vector< std::vector< Tensor< 1, dim, Number > > > &gradients) const

Public Member Functions inherited from Function< dim, Number >
	Function (const unsigned int n_components=1, const Number initial_time=0.0)

virtual	~Function ()=0

Function &	operator= (const Function &f)

virtual void	vector_values (const std::vector< Point< dim > > &points, std::vector< std::vector< Number > > &values) const

virtual void	vector_gradients (const std::vector< Point< dim > > &points, std::vector< std::vector< Tensor< 1, dim, Number > > > &gradients) const

virtual Number	laplacian (const Point< dim > &p, const unsigned int component=0) const

virtual void	vector_laplacian (const Point< dim > &p, Vector< Number > &values) const

virtual void	laplacian_list (const std::vector< Point< dim > > &points, std::vector< Number > &values, const unsigned int component=0) const

virtual void	vector_laplacian_list (const std::vector< Point< dim > > &points, std::vector< Vector< Number > > &values) const

virtual SymmetricTensor< 2, dim, Number >	hessian (const Point< dim > &p, const unsigned int component=0) const

virtual void	vector_hessian (const Point< dim > &p, std::vector< SymmetricTensor< 2, dim, Number > > &values) const

virtual void	hessian_list (const std::vector< Point< dim > > &points, std::vector< SymmetricTensor< 2, dim, Number > > &values, const unsigned int component=0) const

virtual void	vector_hessian_list (const std::vector< Point< dim > > &points, std::vector< std::vector< SymmetricTensor< 2, dim, Number > > > &values) const

std::size_t	memory_consumption () const

Public Member Functions inherited from FunctionTime< Number >
	FunctionTime (const Number initial_time=Number(0.0))

virtual	~FunctionTime ()

Number	get_time () const

virtual void	set_time (const Number new_time)

virtual void	advance_time (const Number delta_t)

Public Member Functions inherited from Subscriptor
	Subscriptor ()

	Subscriptor (const Subscriptor &)

	Subscriptor (Subscriptor &&)

virtual	~Subscriptor ()

Subscriptor &	operator= (const Subscriptor &)

Subscriptor &	operator= (Subscriptor &&)

void	subscribe (const char *identifier=0) const

void	unsubscribe (const char *identifier=0) const

unsigned int	n_subscriptions () const

void	list_subscribers () const

template<class Archive >
void	serialize (Archive &ar, const unsigned int version)

Protected Attributes
std::vector< Number >	function_value_vector

Additional Inherited Members
Static Public Member Functions inherited from Subscriptor
static ::ExceptionBase &	ExcInUse (int arg1, char *arg2, std::string &arg3)

static ::ExceptionBase &	ExcNoSubscriber (char arg1, char arg2)

Public Attributes inherited from Function< dim, Number >
const unsigned int	n_components

Static Public Attributes inherited from Function< dim, Number >
static const unsigned int	dimension = dim

Detailed Description

template<int dim, typename Number = double>
class ConstantFunction< dim, Number >

Provide a function which always returns the constant values handed to the constructor.

Obviously, the derivates of this function are zero, which is why we derive this class from ZeroFunction: we then only have to overload the value functions, not all the derivatives. In some way, it would be more obvious to do the derivation in the opposite direction, i.e. let ZeroFunction be a more specialized version of ConstantFunction; however, this would be less efficient, since we could not make use of the fact that the function value of the ZeroFunction is known at compile time and need not be looked up somewhere in memory.

Author: Wolfgang Bangerth, 1998, 1999, Lei Qiao, 2015

Definition at line 425 of file function.h.

Constructor & Destructor Documentation

◆ ConstantFunction() [1/4]

template<int dim, typename Number = double>

ConstantFunction< dim, Number >::ConstantFunction	(	const Number	value,
		const unsigned int	n_components = `1`
	)

Constructor; set values of all components to the provided one. The default number of components is one.

◆ ConstantFunction() [2/4]

template<int dim, typename Number = double>

ConstantFunction< dim, Number >::ConstantFunction ( const std::vector< Number > & values )

Constructor; takes an std::vector<Number> object as an argument. The number of components is determined by values.size().

◆ ConstantFunction() [3/4]

template<int dim, typename Number = double>

ConstantFunction< dim, Number >::ConstantFunction ( const Vector< Number > & values )

Constructor; takes an Vector<Number> object as an argument. The number of components is determined by values.size().

◆ ConstantFunction() [4/4]

template<int dim, typename Number = double>

ConstantFunction< dim, Number >::ConstantFunction	(	const Number *	begin_ptr,
		const unsigned int	n_components
	)

Constructor; uses whatever stores in [begin_ptr, begin_ptr+n_components) to initialize a new object.

◆ ~ConstantFunction()

template<int dim, typename Number = double>

virtual ConstantFunction< dim, Number >::~ConstantFunction ( )

virtual

Virtual destructor; absolutely necessary in this case.

Member Function Documentation

◆ value()

template<int dim, typename Number = double>

virtual Number ConstantFunction< dim, Number >::value	(	const Point< dim > &	p,
		const unsigned int	component
	)		const

virtual

Return the value of the function at the given point. Unless there is only one component (i.e. the function is scalar), you should state the component you want to have evaluated; it defaults to zero, i.e. the first component.

Reimplemented from ZeroFunction< dim, Number >.

◆ vector_value()

template<int dim, typename Number = double>

virtual void ConstantFunction< dim, Number >::vector_value	(	const Point< dim > &	p,
		Vector< Number > &	values
	)		const

virtual

Return all components of a vector-valued function at a given point.

values shall have the right size beforehand, i.e. n_components.

The default implementation will call value() for each component.

Reimplemented from ZeroFunction< dim, Number >.

Reimplemented in ComponentSelectFunction< dim, Number >.

◆ value_list()

template<int dim, typename Number = double>

virtual void ConstantFunction< dim, Number >::value_list	(	const std::vector< Point< dim > > &	points,
		std::vector< Number > &	values,
		const unsigned int	component = `0`
	)		const

virtual

Set values to the point values of the specified component of the function at the points. It is assumed that values already has the right size, i.e. the same size as the points array.

By default, this function repeatedly calls value() for each point separately, to fill the output array.

Reimplemented from ZeroFunction< dim, Number >.

◆ vector_value_list()

template<int dim, typename Number = double>

virtual void ConstantFunction< dim, Number >::vector_value_list	(	const std::vector< Point< dim > > &	points,
		std::vector< Vector< Number > > &	values
	)		const

virtual

Set values to the point values of the function at the points. It is assumed that values already has the right size, i.e. the same size as the points array, and that all elements be vectors with the same number of components as this function has.

By default, this function repeatedly calls vector_value() for each point separately, to fill the output array.

Reimplemented from ZeroFunction< dim, Number >.

Reimplemented in ComponentSelectFunction< dim, Number >.

Member Data Documentation

◆ function_value_vector

template<int dim, typename Number = double>

std::vector<Number> ConstantFunction< dim, Number >::function_value_vector

protected

Store the constant function value vector.

Definition at line 477 of file function.h.

The documentation for this class was generated from the following file:

deal.II/base/function.h

Public Member Functions

Protected Attributes

Additional Inherited Members

Detailed Description

template<int dim, typename Number = double> class ConstantFunction< dim, Number >

Constructor & Destructor Documentation

◆ ConstantFunction() [1/4]

◆ ConstantFunction() [2/4]

◆ ConstantFunction() [3/4]

◆ ConstantFunction() [4/4]

◆ ~ConstantFunction()

Member Function Documentation

◆ value()

◆ vector_value()

◆ value_list()

◆ vector_value_list()

Member Data Documentation

◆ function_value_vector

template<int dim, typename Number = double>
class ConstantFunction< dim, Number >