Reference documentation for deal.II version Git 803d21ff95 2020-10-01 11:19:45 -0600
TensorFunction< rank, dim, Number > Class Template Reference

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

Inheritance diagram for TensorFunction< rank, dim, Number >:
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## Public Types

using value_type = Tensor< rank, dim, Number >

using gradient_type = Tensor< rank+1, dim, Number >

using time_type = typename FunctionTime< typename numbers::NumberTraits< Number >::real_type >::time_type

## Public Member Functions

TensorFunction (const time_type initial_time=time_type(0.0))

virtual ~TensorFunction () override=default

virtual value_type value (const Point< dim > &p) const

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

numbers::NumberTraits< Number >::real_type get_time () const

virtual void set_time (const numbers::NumberTraits< Number >::real_type new_time)

virtual void advance_time (const numbers::NumberTraits< Number >::real_type delta_t)

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

Subscriptor functionality

Classes derived from Subscriptor provide a facility to subscribe to this object. This is mostly used by the SmartPointer class.

void subscribe (std::atomic< bool > *const validity, const std::string &identifier="") const

void unsubscribe (std::atomic< bool > *const validity, const std::string &identifier="") const

unsigned int n_subscriptions () const

template<typename StreamType >
void list_subscribers (StreamType &stream) const

void list_subscribers () const

## Static Public Member Functions

static ::ExceptionBaseExcInUse (int arg1, std::string arg2, std::string arg3)

static ::ExceptionBaseExcNoSubscriber (std::string arg1, std::string arg2)

## Detailed Description

### template<int rank, int dim, typename Number = double> class TensorFunction< rank, dim, Number >

This class is a model for a tensor valued function. The interface of the class is mostly the same as that for the Function class, with the exception that it does not support vector-valued functions with several components, but that the return type is always tensor-valued. The returned values of the evaluation of objects of this type are always whole tensors, while for the Function class, one can ask for a specific component only, or use the vector_value function, which however does not return the value, but rather writes it into the address provided by its second argument. The reason for the different behaviour of the classes is that in the case of tensor valued functions, the size of the argument is known to the compiler a priori, such that the correct amount of memory can be allocated on the stack for the return value; on the other hand, for the vector valued functions, the size is not known to the compiler, so memory has to be allocated on the heap, resulting in relatively expensive copy operations. One can therefore consider this class a specialization of the Function class for which the size is known. An additional benefit is that tensors of arbitrary rank can be returned, not only vectors, as for them the size can be determined similarly simply.

Definition at line 56 of file tensor_function.h.

## ◆ value_type

template<int rank, int dim, typename Number = double>
 using TensorFunction< rank, dim, Number >::value_type = Tensor

Alias for the return types of the value function.

Definition at line 64 of file tensor_function.h.

template<int rank, int dim, typename Number = double>
 using TensorFunction< rank, dim, Number >::gradient_type = Tensor

Alias for the return types of the gradient functions.

Definition at line 69 of file tensor_function.h.

## ◆ time_type

template<int rank, int dim, typename Number = double>
 using TensorFunction< rank, dim, Number >::time_type = typename FunctionTime< typename numbers::NumberTraits::real_type>::time_type

The scalar-valued real type used for representing time.

Definition at line 75 of file tensor_function.h.

## ◆ TensorFunction()

template<int rank, int dim, typename Number = double>
 TensorFunction< rank, dim, Number >::TensorFunction ( const time_type initial_time = time_type(0.0) )

Constructor. May take an initial value for the time variable, which defaults to zero.

## ◆ ~TensorFunction()

template<int rank, int dim, typename Number = double>
 virtual TensorFunction< rank, dim, Number >::~TensorFunction ( )
overridevirtualdefault

Virtual destructor; absolutely necessary in this case, as classes are usually not used by their true type, but rather through pointers to this base class.

## ◆ value()

template<int rank, int dim, typename Number = double>
 virtual value_type TensorFunction< rank, dim, Number >::value ( const Point< dim > & p ) const
virtual

Return the value of the function at the given point.

Reimplemented in TensorFunctionParser< rank, dim, Number >, and ConstantTensorFunction< rank, dim, Number >.

## ◆ value_list()

template<int rank, int dim, typename Number = double>
 virtual void TensorFunction< rank, dim, Number >::value_list ( const std::vector< Point< dim >> & points, std::vector< value_type > & 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.

template<int rank, int dim, typename Number = double>
 virtual gradient_type TensorFunction< rank, dim, Number >::gradient ( const Point< dim > & p ) const
virtual

Return the gradient of the function at the given point.

Reimplemented in ConstantTensorFunction< rank, dim, Number >.

template<int rank, int dim, typename Number = double>
 virtual void TensorFunction< rank, dim, Number >::gradient_list ( const std::vector< Point< dim >> & points, std::vector< gradient_type > & gradients ) const
virtual

Set gradients to the gradients 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.

## ◆ get_time()

 numbers::NumberTraits< Number >::real_type FunctionTime< numbers::NumberTraits< Number >::real_type >::get_time ( ) const
inherited

Return the value of the time variable.

## ◆ set_time()

 virtual void FunctionTime< numbers::NumberTraits< Number >::real_type >::set_time ( const numbers::NumberTraits< Number >::real_type new_time )
virtualinherited

Set the time to new_time, overwriting the old value.

 virtual void FunctionTime< numbers::NumberTraits< Number >::real_type >::advance_time ( const numbers::NumberTraits< Number >::real_type delta_t )
virtualinherited

Advance the time by the given time step delta_t.

## ◆ subscribe()

 void Subscriptor::subscribe ( std::atomic< bool > *const validity, const std::string & identifier = "" ) const
inherited

Subscribes a user of the object by storing the pointer validity. The subscriber may be identified by text supplied as identifier.

Definition at line 136 of file subscriptor.cc.

## ◆ unsubscribe()

 void Subscriptor::unsubscribe ( std::atomic< bool > *const validity, const std::string & identifier = "" ) const
inherited

Unsubscribes a user from the object.

Note
The identifier and the validity pointer must be the same as the one supplied to subscribe().

Definition at line 156 of file subscriptor.cc.

## ◆ n_subscriptions()

 unsigned int Subscriptor::n_subscriptions ( ) const
inlineinherited

Return the present number of subscriptions to this object. This allows to use this class for reference counted lifetime determination where the last one to unsubscribe also deletes the object.

Definition at line 300 of file subscriptor.h.

## ◆ list_subscribers() [1/2]

template<typename StreamType >
 void Subscriptor::list_subscribers ( StreamType & stream ) const
inlineinherited

List the subscribers to the input stream.

Definition at line 317 of file subscriptor.h.

## ◆ list_subscribers() [2/2]

 void Subscriptor::list_subscribers ( ) const
inherited

List the subscribers to deallog.

Definition at line 204 of file subscriptor.cc.

## ◆ serialize()

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

Read or write the data of this object to or from a stream for the purpose of serialization.

This function does not actually serialize any of the member variables of this class. The reason is that what this class stores is only who subscribes to this object, but who does so at the time of storing the contents of this object does not necessarily have anything to do with who subscribes to the object when it is restored. Consequently, we do not want to overwrite the subscribers at the time of restoring, and then there is no reason to write the subscribers out in the first place.

Definition at line 309 of file subscriptor.h.

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