Reference documentation for deal.II version GIT 2f5445400b 2023-02-05 22:30:02+00:00
DataPostprocessorScalar< dim > Class Template Reference

#include <deal.II/numerics/data_postprocessor.h>

Inheritance diagram for DataPostprocessorScalar< dim >:
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## Public Member Functions

DataPostprocessorScalar (const std::string &name, const UpdateFlags update_flags)

virtual std::vector< std::string > get_names () const override

virtual std::vector< DataComponentInterpretation::DataComponentInterpretationget_data_component_interpretation () const override

virtual UpdateFlags get_needed_update_flags () const override

virtual void evaluate_scalar_field (const DataPostprocessorInputs::Scalar< dim > &input_data, std::vector< Vector< double >> &computed_quantities) const

virtual void evaluate_vector_field (const DataPostprocessorInputs::Vector< dim > &input_data, std::vector< Vector< double >> &computed_quantities) const

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)

## Private Types

using map_value_type = decltype(counter_map)::value_type

using map_iterator = decltype(counter_map)::iterator

## Private Member Functions

void check_no_subscribers () const noexcept

## Private Attributes

const std::string name

const UpdateFlags update_flags

std::atomic< unsigned int > counter

std::map< std::string, unsigned int > counter_map

std::vector< std::atomic< bool > * > validity_pointers

const std::type_info * object_info

## Static Private Attributes

static std::mutex mutex

## Detailed Description

### template<int dim> class DataPostprocessorScalar< dim >

This class provides a simpler interface to the functionality offered by the DataPostprocessor class in case one wants to compute only a single scalar quantity from the finite element field passed to the DataOut class. For this particular case, it is clear what the returned value of DataPostprocessor::get_data_component_interpretation() should be and we pass the values returned by get_names() and get_needed_update_flags() to the constructor so that derived classes do not have to implement these functions by hand.

All derived classes have to do is implement a constructor and overload either DataPostprocessor::evaluate_scalar_field() or DataPostprocessor::evaluate_vector_field() as discussed in the DataPostprocessor class's documentation.

An example of how this class can be used can be found in step-29 for the case where we are interested in computing the magnitude (a scalar) of a complex-valued solution. While in step-29, the solution vector consists of separate real and imaginary parts of the solution, step-58 computes the solution vector as a vector with complex entries and the DataPostprocessorScalar class is used there to compute the magnitude and phase of the solution in a different way there.

An example of how the closely related DataPostprocessorVector class can be used is found in the documentation of that class. The same is true for the DataPostprocessorTensor class.

Definition at line 701 of file data_postprocessor.h.

## ◆ map_value_type

 using Subscriptor::map_value_type = decltype(counter_map)::value_type
privateinherited

The data type used in counter_map.

Definition at line 230 of file subscriptor.h.

## ◆ map_iterator

 using Subscriptor::map_iterator = decltype(counter_map)::iterator
privateinherited

The iterator type used in counter_map.

Definition at line 235 of file subscriptor.h.

## ◆ DataPostprocessorScalar()

template<int dim>
 DataPostprocessorScalar< dim >::DataPostprocessorScalar ( const std::string & name, const UpdateFlags update_flags )

Constructor. Take the name of the single scalar variable computed by classes derived from the current one, as well as the update flags necessary to compute this quantity.

Parameters
 name The name by which the scalar variable computed by this class should be made available in graphical output files. update_flags This has to be a combination of update_values, update_gradients, update_hessians and update_quadrature_points. Note that the flag update_quadrature_points updates DataPostprocessorInputs::CommonInputs::evaluation_points. If the DataPostprocessor is to be used in combination with DataOutFaces, you may also ask for a update of normals via the update_normal_vectors flag. The description of the flags can be found at UpdateFlags.

Definition at line 83 of file data_postprocessor.cc.

## ◆ get_names()

template<int dim>
 std::vector< std::string > DataPostprocessorScalar< dim >::get_names
overridevirtual

Return the vector of strings describing the names of the computed quantities. Given the purpose of this class, this is a vector with a single entry equal to the name given to the constructor.

Implements DataPostprocessor< dim >.

Definition at line 94 of file data_postprocessor.cc.

## ◆ get_data_component_interpretation()

template<int dim>
 std::vector< DataComponentInterpretation::DataComponentInterpretation > DataPostprocessorScalar< dim >::get_data_component_interpretation
overridevirtual

This function returns information about how the individual components of output files that consist of more than one data set are to be interpreted. Since the current class is meant to be used for a single scalar result variable, the returned value is obviously DataComponentInterpretation::component_is_scalar.

Reimplemented from DataPostprocessor< dim >.

Definition at line 103 of file data_postprocessor.cc.

## ◆ get_needed_update_flags()

template<int dim>
 UpdateFlags DataPostprocessorScalar< dim >::get_needed_update_flags
overridevirtual

Return, which data has to be provided to compute the derived quantities. The flags returned here are the ones passed to the constructor of this class.

Implements DataPostprocessor< dim >.

Definition at line 112 of file data_postprocessor.cc.

## ◆ evaluate_scalar_field()

template<int dim>
 void DataPostprocessor< dim >::evaluate_scalar_field ( const DataPostprocessorInputs::Scalar< dim > & input_data, std::vector< Vector< double >> & computed_quantities ) const
virtualinherited

This is the main function which actually performs the postprocessing. The second argument is a reference to the postprocessed data which already has correct size and must be filled by this function.

The function takes the values, gradients, and higher derivatives of the solution at all evaluation points, as well as other data such as the cell, via the first argument. Not all of the member vectors of this argument will be filled with data – in fact, derivatives and other quantities will only be contain valid data if the corresponding flags are returned by an overridden version of the get_needed_update_flags() function (implemented in a user's derived class). Otherwise those vectors will be in an unspecified state.

This function is called when the finite element field that is being converted into graphical data by DataOut or similar classes represents scalar data, i.e., if the finite element in use has only a single real-valued vector component.

Reimplemented in DataPostprocessors::BoundaryIds< dim >.

Definition at line 49 of file data_postprocessor.cc.

## ◆ evaluate_vector_field()

template<int dim>
 void DataPostprocessor< dim >::evaluate_vector_field ( const DataPostprocessorInputs::Vector< dim > & input_data, std::vector< Vector< double >> & computed_quantities ) const
virtualinherited

Same as the evaluate_scalar_field() function, but this function is called when the original data vector represents vector data, i.e., the finite element in use has multiple vector components. This function is also called if the finite element is scalar but the solution vector is complex-valued. If the solution vector to be visualized is complex-valued (whether scalar or not), then the input data contains first all real parts of the solution vector at each evaluation point, and then all imaginary parts.

Definition at line 60 of file data_postprocessor.cc.

## ◆ 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 using the BOOST serialization library.

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.

## ◆ check_no_subscribers()

 void Subscriptor::check_no_subscribers ( ) const
privatenoexceptinherited

Check that there are no objects subscribing to this object. If this check passes then it is safe to destroy the current object. It this check fails then this function will either abort or print an error message to deallog (by using the AssertNothrow mechanism), but will not throw an exception.

Note
Since this function is just a consistency check it does nothing in release mode.
If this function is called when there is an uncaught exception then, rather than aborting, this function prints an error message to the standard error stream and returns.

Definition at line 53 of file subscriptor.cc.

## ◆ name

template<int dim>
 const std::string DataPostprocessorScalar< dim >::name
private

Copies of the two arguments given to the constructor of this class.

Definition at line 752 of file data_postprocessor.h.

## ◆ update_flags

template<int dim>
 const UpdateFlags DataPostprocessorScalar< dim >::update_flags
private

Definition at line 753 of file data_postprocessor.h.

## ◆ counter

 std::atomic Subscriptor::counter
mutableprivateinherited

Store the number of objects which subscribed to this object. Initially, this number is zero, and upon destruction it shall be zero again (i.e. all objects which subscribed should have unsubscribed again).

The creator (and owner) of an object is counted in the map below if HE manages to supply identification.

We use the mutable keyword in order to allow subscription to constant objects also.

This counter may be read from and written to concurrently in multithreaded code: hence we use the std::atomic class template.

Definition at line 219 of file subscriptor.h.

## ◆ counter_map

 std::map Subscriptor::counter_map
mutableprivateinherited

In this map, we count subscriptions for each different identification string supplied to subscribe().

Definition at line 225 of file subscriptor.h.

## ◆ validity_pointers

 std::vector *> Subscriptor::validity_pointers
mutableprivateinherited

In this vector, we store pointers to the validity bool in the SmartPointer objects that subscribe to this class.

Definition at line 241 of file subscriptor.h.

## ◆ object_info

 const std::type_info* Subscriptor::object_info
mutableprivateinherited

Pointer to the typeinfo object of this object, from which we can later deduce the class name. Since this information on the derived class is neither available in the destructor, nor in the constructor, we obtain it in between and store it here.

Definition at line 249 of file subscriptor.h.

## ◆ mutex

 std::mutex Subscriptor::mutex
staticprivateinherited

A mutex used to ensure data consistency when printing out the list of subscribers.

Definition at line 271 of file subscriptor.h.

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