Reference documentation for deal.II version Git 497f915867 2021-09-17 22:46:48 +0200
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Public Types | Public Member Functions | Static Public Member Functions | Public Attributes | Static Public Attributes | Private Attributes | List of all members
FunctionDerivative< dim > Class Template Reference

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

Inheritance diagram for FunctionDerivative< dim >:
[legend]

Public Types

enum  DifferenceFormula { Euler, UpwindEuler, FourthOrder }
 
using time_type = typename FunctionTime< typename numbers::NumberTraits< double >::real_type >::time_type
 

Public Member Functions

 FunctionDerivative (const Function< dim > &f, const Point< dim > &direction, const double h=1.e-6)
 
 FunctionDerivative (const Function< dim > &f, const std::vector< Point< dim >> &direction, const double h=1.e-6)
 
void set_formula (typename AutoDerivativeFunction< dim >::DifferenceFormula formula=AutoDerivativeFunction< dim >::Euler)
 
void set_h (const double h)
 
virtual double value (const Point< dim > &p, const unsigned int component=0) const override
 
virtual void vector_value (const Point< dim > &p, Vector< double > &value) const override
 
virtual void value_list (const std::vector< Point< dim >> &points, std::vector< double > &values, const unsigned int component=0) const override
 
virtual std::size_t memory_consumption () const override
 
void set_formula (const DifferenceFormula formula=Euler)
 
virtual Tensor< 1, dim > gradient (const Point< dim > &p, const unsigned int component=0) const override
 
virtual void vector_gradient (const Point< dim > &p, std::vector< Tensor< 1, dim >> &gradients) const override
 
virtual void vector_gradient (const Point< dim > &p, std::vector< Tensor< 1, dim, double >> &gradients) const
 
virtual void gradient_list (const std::vector< Point< dim >> &points, std::vector< Tensor< 1, dim >> &gradients, const unsigned int component=0) const override
 
virtual void gradient_list (const std::vector< Point< dim >> &points, std::vector< Tensor< 1, dim, double >> &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 override
 
virtual void vector_gradient_list (const std::vector< Point< dim >> &points, std::vector< std::vector< Tensor< 1, dim, double >>> &gradients) const
 
virtual void vector_value_list (const std::vector< Point< dim >> &points, std::vector< Vector< double >> &values) const
 
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, double >>> &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
 
virtual SymmetricTensor< 2, dim, doublehessian (const Point< dim > &p, const unsigned int component=0) const
 
virtual void vector_hessian (const Point< dim > &p, std::vector< SymmetricTensor< 2, dim, double >> &values) const
 
virtual void hessian_list (const std::vector< Point< dim >> &points, std::vector< SymmetricTensor< 2, dim, double >> &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, double >>> &values) const
 
Number get_time () const
 
virtual void set_time (const Number new_time)
 
virtual void advance_time (const Number 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 DifferenceFormula get_formula_of_order (const unsigned int ord)
 
static ::ExceptionBaseExcInUse (int arg1, std::string arg2, std::string arg3)
 
static ::ExceptionBaseExcNoSubscriber (std::string arg1, std::string arg2)
 

Public Attributes

const unsigned int n_components
 

Static Public Attributes

static const unsigned int dimension
 

Private Attributes

const Function< dim > & f
 
double h
 
AutoDerivativeFunction< dim >::DifferenceFormula formula
 
std::vector< Tensor< 1, dim > > incr
 

Detailed Description

template<int dim>
class FunctionDerivative< dim >

Derivative of a function object. The value access functions of this class return the directional derivative of a function with respect to a direction provided on construction. If b is the vector, the derivative b . grad f is computed. This derivative is evaluated directly, not by computing the gradient of f and its scalar product with b.

The derivative is computed numerically, using one of the provided difference formulas (see set_formula for available schemes). Experimenting with h and the difference scheme may be necessary to obtain sufficient results.

Definition at line 44 of file function_derivative.h.

Member Typedef Documentation

◆ time_type

using Function< dim, double >::time_type = typename FunctionTime< typename numbers::NumberTraits<double >::real_type>::time_type
inherited

The scalar-valued real type used for representing time.

Definition at line 170 of file function.h.

Member Enumeration Documentation

◆ DifferenceFormula

template<int dim>
enum AutoDerivativeFunction::DifferenceFormula
inherited

Names of difference formulas.

Enumerator
Euler 

The symmetric Euler formula of second order:

\[ u'(t) \approx \frac{u(t+h) - u(t-h)}{2h}. \]

UpwindEuler 

The upwind Euler formula of first order:

\[ u'(t) \approx \frac{u(t) - u(t-h)}{h}. \]

FourthOrder 

The fourth order scheme

\[ u'(t) \approx \frac{u(t-2h) - 8u(t-h) + 8u(t+h) - u(t+2h)}{12h}. \]

Definition at line 88 of file auto_derivative_function.h.

Constructor & Destructor Documentation

◆ FunctionDerivative() [1/2]

template<int dim>
FunctionDerivative< dim >::FunctionDerivative ( const Function< dim > &  f,
const Point< dim > &  direction,
const double  h = 1.e-6 
)

Constructor. Provided are the functions to compute derivatives of, the direction vector of the differentiation and the step size h of the difference formula.

Definition at line 26 of file function_derivative.cc.

◆ FunctionDerivative() [2/2]

template<int dim>
FunctionDerivative< dim >::FunctionDerivative ( const Function< dim > &  f,
const std::vector< Point< dim >> &  direction,
const double  h = 1.e-6 
)

Constructor. Provided are the functions to compute derivatives of and the direction vector of the differentiation in each quadrature point and the difference step size.

This is the constructor for a variable velocity field. Most probably, a new object of FunctionDerivative has to be constructed for each set of quadrature points.

The number of quadrature point must still be the same, when values are accessed.

Definition at line 40 of file function_derivative.cc.

Member Function Documentation

◆ set_formula() [1/2]

template<int dim>
void FunctionDerivative< dim >::set_formula ( typename AutoDerivativeFunction< dim >::DifferenceFormula  formula = AutoDerivativeFunction<dim>::Euler)

Choose the difference formula. This is set to the default in the constructor.

Formulas implemented right now are first order backward Euler (UpwindEuler), second order symmetric Euler (Euler) and a symmetric fourth order formula (FourthOrder).

Definition at line 57 of file function_derivative.cc.

◆ set_h()

template<int dim>
void FunctionDerivative< dim >::set_h ( const double  h)

Change the base step size of the difference formula

Definition at line 81 of file function_derivative.cc.

◆ value()

template<int dim>
double FunctionDerivative< dim >::value ( const Point< dim > &  p,
const unsigned int  component = 0 
) const
overridevirtual

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 Function< dim >.

Definition at line 92 of file function_derivative.cc.

◆ vector_value()

template<int dim>
void FunctionDerivative< dim >::vector_value ( const Point< dim > &  p,
Vector< double > &  values 
) const
overridevirtual

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 Function< dim >.

Definition at line 123 of file function_derivative.cc.

◆ value_list()

template<int dim>
void FunctionDerivative< dim >::value_list ( const std::vector< Point< dim >> &  points,
std::vector< double > &  values,
const unsigned int  component = 0 
) const
overridevirtual

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 Function< dim >.

Definition at line 165 of file function_derivative.cc.

◆ memory_consumption()

template<int dim>
std::size_t FunctionDerivative< dim >::memory_consumption ( ) const
overridevirtual

Return an estimate for the memory consumption, in bytes, of this object. This is not exact (but will usually be close) because calculating the memory usage of trees (e.g., std::map) is difficult.

Reimplemented from Function< dim >.

Definition at line 231 of file function_derivative.cc.

◆ set_formula() [2/2]

template<int dim>
void AutoDerivativeFunction< dim >::set_formula ( const DifferenceFormula  formula = Euler)
inherited

Choose the difference formula. See the enum DifferenceFormula for available choices.

Definition at line 43 of file auto_derivative_function.cc.

◆ gradient()

template<int dim>
Tensor< 1, dim > AutoDerivativeFunction< dim >::gradient ( const Point< dim > &  p,
const unsigned int  component = 0 
) const
overridevirtualinherited

Return the gradient of the specified component of the function at the given point.

Compute numerical difference quotients using the preset DifferenceFormula.

Reimplemented from Function< dim >.

Definition at line 75 of file auto_derivative_function.cc.

◆ vector_gradient() [1/2]

template<int dim>
void AutoDerivativeFunction< dim >::vector_gradient ( const Point< dim > &  p,
std::vector< Tensor< 1, dim >> &  gradients 
) const
overridevirtualinherited

Return the gradient of all components of the function at the given point.

Compute numerical difference quotients using the preset DifferenceFormula.

Definition at line 127 of file auto_derivative_function.cc.

◆ vector_gradient() [2/2]

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

Return the gradient of all components of the function at the given point.

◆ gradient_list() [1/2]

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

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

Compute numerical difference quotients using the preset DifferenceFormula.

Definition at line 204 of file auto_derivative_function.cc.

◆ gradient_list() [2/2]

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

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

◆ vector_gradient_list() [1/2]

template<int dim>
void AutoDerivativeFunction< dim >::vector_gradient_list ( const std::vector< Point< dim >> &  points,
std::vector< std::vector< Tensor< 1, dim >>> &  gradients 
) const
overridevirtualinherited

Set gradients to the gradients of the function at the points, for all components. It is assumed that gradients already has the right size, i.e. the same size as the points array.

The outer loop over gradients is over the points in the list, the inner loop over the different components of the function.

Compute numerical difference quotients using the preset DifferenceFormula.

Definition at line 268 of file auto_derivative_function.cc.

◆ vector_gradient_list() [2/2]

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

Set gradients to the gradients of the function at the points, for all components. It is assumed that gradients already has the right size, i.e. the same size as the points array.

The outer loop over gradients is over the points in the list, the inner loop over the different components of the function.

◆ get_formula_of_order()

template<int dim>
AutoDerivativeFunction< dim >::DifferenceFormula AutoDerivativeFunction< dim >::get_formula_of_order ( const unsigned int  ord)
staticinherited

Return a DifferenceFormula of the order ord at minimum.

Definition at line 336 of file auto_derivative_function.cc.

◆ vector_value_list()

virtual void Function< dim, double >::vector_value_list ( const std::vector< Point< dim >> &  points,
std::vector< Vector< double >> &  values 
) const
virtualinherited

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 in Functions::CutOffFunctionCinfty< dim >, Functions::CutOffFunctionC1< dim >, Functions::CutOffFunctionW1< dim >, Functions::CutOffFunctionLinfty< dim >, Functions::SlitSingularityFunction< dim >, Functions::CosineGradFunction< dim >, Functions::CosineFunction< dim >, Functions::FlowFunction< dim >, Functions::FlowFunction< 2 >, and Functions::Q1WedgeFunction< dim >.

◆ vector_values()

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

For each component of the function, fill a vector of values, one for each point.

The default implementation of this function in Function calls value_list() for each component. In order to improve performance, this can be reimplemented in derived classes to speed up performance.

Reimplemented in Functions::StokesCosine< dim >, Functions::PoisseuilleFlow< dim >, Functions::FlowFunction< dim >, and Functions::FlowFunction< 2 >.

◆ vector_gradients()

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

For each component of the function, fill a vector of gradient values, one for each point.

The default implementation of this function in Function calls value_list() for each component. In order to improve performance, this can be reimplemented in derived classes to speed up performance.

◆ laplacian()

virtual double Function< dim, double >::laplacian ( const Point< dim > &  p,
const unsigned int  component = 0 
) const
virtualinherited

◆ vector_laplacian()

virtual void Function< dim, double >::vector_laplacian ( const Point< dim > &  p,
Vector< double > &  values 
) const
virtualinherited

Compute the Laplacian of all components at point p and store them in values.

◆ laplacian_list()

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

◆ vector_laplacian_list()

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

Compute the Laplacians of all components at a set of points.

Reimplemented in Functions::FlowFunction< dim >, and Functions::FlowFunction< 2 >.

◆ hessian()

virtual SymmetricTensor<2, dim, double > Function< dim, double >::hessian ( const Point< dim > &  p,
const unsigned int  component = 0 
) const
virtualinherited

Compute the Hessian of a given component at point p, that is the gradient of the gradient of the function.

Reimplemented in Functions::CosineFunction< dim >, Functions::LevelSet::Plane< dim >, Functions::CSpline< dim >, Functions::Spherical< dim >, Functions::LevelSet::Sphere< dim >, and Functions::CoordinateRestriction< dim >.

◆ vector_hessian()

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

Compute the Hessian of all components at point p and store them in values.

◆ hessian_list()

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

Compute the Hessian of one component at a set of points.

◆ vector_hessian_list()

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

Compute the Hessians of all components at a set of points.

◆ get_time()

template<typename Number = double>
Number FunctionTime< Number >::get_time ( ) const
inherited

Return the value of the time variable.

◆ set_time()

template<typename Number = double>
virtual void FunctionTime< Number >::set_time ( const Number  new_time)
virtualinherited

Set the time to new_time, overwriting the old value.

◆ advance_time()

template<typename Number = double>
virtual void FunctionTime< Number >::advance_time ( const Number  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 301 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 318 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 310 of file subscriptor.h.

Member Data Documentation

◆ f

template<int dim>
const Function<dim>& FunctionDerivative< dim >::f
private

Function for differentiation.

Definition at line 112 of file function_derivative.h.

◆ h

template<int dim>
double FunctionDerivative< dim >::h
private

Step size of the difference formula.

Definition at line 117 of file function_derivative.h.

◆ formula

template<int dim>
AutoDerivativeFunction<dim>::DifferenceFormula FunctionDerivative< dim >::formula
private

Difference formula.

Definition at line 122 of file function_derivative.h.

◆ incr

template<int dim>
std::vector<Tensor<1, dim> > FunctionDerivative< dim >::incr
private

Helper object. Contains the increment vector for the formula.

Definition at line 127 of file function_derivative.h.

◆ dimension

const unsigned int Function< dim, double >::dimension
staticinherited

Export the value of the template parameter as a static member constant. Sometimes useful for some expression template programming.

Definition at line 159 of file function.h.

◆ n_components

const unsigned int Function< dim, double >::n_components
inherited

Number of vector components.

Definition at line 164 of file function.h.


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