Reference documentation for deal.II version Git cd4d0b9268 2020-11-30 14:25:08 -0500
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Public Member Functions | Static Public Member Functions | Private Attributes | List of all members
DataPostprocessorScalar< dim > Class Template Reference

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

Inheritance diagram for DataPostprocessorScalar< dim >:

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 Attributes

const std::string name
const UpdateFlags update_flags

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 645 of file data_postprocessor.h.

Constructor & Destructor Documentation

◆ 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.

nameThe name by which the scalar variable computed by this class should be made available in graphical output files.
update_flagsThis 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 60 of file

Member Function Documentation

◆ get_names()

template<int dim>
std::vector< std::string > DataPostprocessorScalar< dim >::get_names ( ) const

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 71 of file

◆ get_data_component_interpretation()

template<int dim>
std::vector< DataComponentInterpretation::DataComponentInterpretation > DataPostprocessorScalar< dim >::get_data_component_interpretation ( ) const

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 80 of file

◆ get_needed_update_flags()

template<int dim>
UpdateFlags DataPostprocessorScalar< dim >::get_needed_update_flags ( ) const

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 89 of file

◆ 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

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.

Definition at line 26 of file

◆ 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

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 37 of file

◆ subscribe()

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

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

◆ unsubscribe()

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

Unsubscribes a user from the object.

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

Definition at line 156 of file

◆ n_subscriptions()

unsigned int Subscriptor::n_subscriptions ( ) const

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

List the subscribers to the input stream.

Definition at line 317 of file subscriptor.h.

◆ list_subscribers() [2/2]

void Subscriptor::list_subscribers ( ) const

List the subscribers to deallog.

Definition at line 204 of file

◆ serialize()

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

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.

Member Data Documentation

◆ name

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

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

Definition at line 696 of file data_postprocessor.h.

◆ update_flags

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

Definition at line 697 of file data_postprocessor.h.

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