Reference documentation for deal.II version 8.1.0
Public Member Functions | Protected Attributes | List of all members
ConstantFunction< dim > Class Template Reference

#include <function.h>

Inheritance diagram for ConstantFunction< dim >:
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Public Member Functions

 ConstantFunction (const double value, const unsigned int n_components=1)
 
virtual ~ConstantFunction ()
 
virtual double value (const Point< dim > &p, const unsigned int component) const
 
virtual void vector_value (const Point< dim > &p, Vector< double > &return_value) const
 
virtual void value_list (const std::vector< Point< dim > > &points, std::vector< double > &values, const unsigned int component=0) const
 
virtual void vector_value_list (const std::vector< Point< dim > > &points, std::vector< Vector< double > > &values) const
 
std::size_t memory_consumption () const
 
- Public Member Functions inherited from ZeroFunction< dim >
 ZeroFunction (const unsigned int n_components=1)
 
virtual ~ZeroFunction ()
 
virtual Tensor< 1, dim > gradient (const Point< dim > &p, const unsigned int component=0) const
 
virtual void vector_gradient (const Point< dim > &p, std::vector< Tensor< 1, dim > > &gradients) const
 
virtual void gradient_list (const std::vector< Point< dim > > &points, std::vector< Tensor< 1, dim > > &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 > > > &gradients) const
 
- Public Member Functions inherited from Function< dim >
 Function (const unsigned int n_components=1, const double initial_time=0.0)
 
virtual ~Function ()=0
 
Functionoperator= (const Function &f)
 
virtual void vector_values (const std::vector< Point< dim > > &points, std::vector< std::vector< double > > &values) const
 
virtual void vector_gradients (const std::vector< Point< dim > > &points, std::vector< std::vector< Tensor< 1, dim > > > &gradients) const
 
virtual double laplacian (const Point< dim > &p, const unsigned int component=0) const
 
virtual void vector_laplacian (const Point< dim > &p, Vector< double > &values) const
 
virtual void laplacian_list (const std::vector< Point< dim > > &points, std::vector< double > &values, const unsigned int component=0) const
 
virtual void vector_laplacian_list (const std::vector< Point< dim > > &points, std::vector< Vector< double > > &values) const
 
std::size_t memory_consumption () const
 
- Public Member Functions inherited from FunctionTime
 FunctionTime (const double initial_time=0.0)
 
virtual ~FunctionTime ()
 
double get_time () const
 
virtual void set_time (const double new_time)
 
virtual void advance_time (const double delta_t)
 
- Public Member Functions inherited from Subscriptor
 Subscriptor ()
 
 Subscriptor (const Subscriptor &)
 
virtual ~Subscriptor ()
 
Subscriptoroperator= (const Subscriptor &)
 
void subscribe (const char *identifier=0) const
 
void unsubscribe (const char *identifier=0) const
 
unsigned int n_subscriptions () const
 
void list_subscribers () const
 
 DeclException3 (ExcInUse, int, char *, std::string &,<< "Object of class "<< arg2<< " is still used by "<< arg1<< " other objects.\n"<< "(Additional information: "<< arg3<< ")\n"<< "Note the entry in the Frequently Asked Questions of "<< "deal.II (linked to from http://www.dealii.org/) for "<< "more information on what this error means.")
 
 DeclException2 (ExcNoSubscriber, char *, char *,<< "No subscriber with identifier \""<< arg2<< "\" did subscribe to this object of class "<< arg1)
 
template<class Archive >
void serialize (Archive &ar, const unsigned int version)
 

Protected Attributes

const double function_value
 

Additional Inherited Members

- Public Attributes inherited from Function< dim >
const unsigned int n_components
 
- Static Public Attributes inherited from Function< dim >
static const unsigned int dimension = dim
 

Detailed Description

template<int dim>
class ConstantFunction< dim >

Provide a function which always returns the constant value 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.

You can pass to the constructor an integer denoting the number of components this function shall have. It defaults to one. If it is greater than one, then the function will return the constant value in all its components, which might not be overly useful a feature in most cases, however.

Author
Wolfgang Bangerth, 1998, 1999

Definition at line 393 of file function.h.

Constructor & Destructor Documentation

template<int dim>
ConstantFunction< dim >::ConstantFunction ( const double  value,
const unsigned int  n_components = 1 
)

Constructor; takes the constant function value as an argument. The number of components is preset to one.

template<int dim>
virtual ConstantFunction< dim >::~ConstantFunction ( )
virtual

Virtual destructor; absolutely necessary in this case.

Member Function Documentation

template<int dim>
virtual double ConstantFunction< dim >::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 >.

template<int dim>
virtual void ConstantFunction< dim >::vector_value ( const Point< dim > &  p,
Vector< double > &  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.

Reimplemented from ZeroFunction< dim >.

Reimplemented in ComponentSelectFunction< dim >.

template<int dim>
virtual void ConstantFunction< dim >::value_list ( const std::vector< Point< dim > > &  points,
std::vector< double > &  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.

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

Reimplemented from ZeroFunction< dim >.

template<int dim>
virtual void ConstantFunction< dim >::vector_value_list ( const std::vector< Point< dim > > &  points,
std::vector< Vector< double > > &  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.

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

Reimplemented from ZeroFunction< dim >.

Reimplemented in ComponentSelectFunction< dim >.

Member Data Documentation

template<int dim>
const double ConstantFunction< dim >::function_value
protected

Store the constant function value.

Definition at line 427 of file function.h.


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