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

Inheritance diagram for QSimplex< dim >:

Public Types
using	SubQuadrature = Quadrature< dim==0 ? 0 :dim - 1 >

Public Member Functions
	QSimplex (const Quadrature< dim > &quad)

Quadrature< dim >	compute_affine_transformation (const std::array< Point< dim >, dim+1 > &vertices) const

bool	operator== (const Quadrature< dim > &p) const

void	initialize (const std::vector< Point< dim > > &points, const std::vector< double > &weights)

unsigned int	size () const

const Point< dim > &	point (const unsigned int i) const

const std::vector< Point< dim > > &	get_points () const

double	weight (const unsigned int i) const

const std::vector< double > &	get_weights () const

std::size_t	memory_consumption () const

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

bool	is_tensor_product () const

const std::array< Quadrature< 1 >, dim > &	get_tensor_basis () const

Protected Attributes
std::vector< Point< dim > >	quadrature_points

std::vector< double >	weights

bool	is_tensor_product_flag

std::unique_ptr< std::array< Quadrature< 1 >, dim > >	tensor_basis

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

using	map_value_type = decltype(counter_map)::value_type

using	map_iterator = decltype(counter_map)::iterator

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 std::mutex	mutex

static ::ExceptionBase &	ExcInUse (int arg1, std::string arg2, std::string arg3)

static ::ExceptionBase &	ExcNoSubscriber (std::string arg1, std::string arg2)

void	check_no_subscribers () const noexcept

Detailed Description

template<int dim>
class QSimplex< dim >

Given an arbitrary quadrature formula, return one that chops the quadrature points above the hyper-plane defined by \(\sum_i x_i = 1\). In other words, it extracts those quadrature points from the base formula that satisfy \(\sum_i (\mathbf x_q)_i \le 1+10^{-12}\)."

In general the resulting quadrature is not very useful, unless the quadrature you started from has been constructed specifically to integrate over triangles or tetrahedra. This class only ensures that the resulting quadrature formula only has quadrature points in the reference simplex or on its boundary.

No transformation is applied to the weights, and the weights referring to points that live outside the reference simplex are simply discarded. Because this leads to (or may lead to) a sum of quadrature weights that do not equal the area of the simplex, the resulting quadrature formula is not useful for actually computing integrals.

The main use of this quadrature formula is not to chop tensor product quadratures. Ideally you should pass to this class a quadrature formula constructed directly using points and weights in the reference simplex, capable of integrating on triangles or tetrahedra.

For finite elements based on quadrilaterals and hexahedra, a QSimplex quadrature formula is not very useful on its own. This class is typically used in conjunction with other classes, like QSplit, to patch the reference element using several QSimplex quadrature formulas.

Such quadrature formulas are useful to integrate functions with singularities at certain points, or functions that present jumps along a co-dimension one surface inside the reference element, like in the extended finite element method (XFEM).

Definition at line 616 of file quadrature_lib.h.

Member Typedef Documentation

◆ SubQuadrature

template<int dim>

using Quadrature< dim >::SubQuadrature = Quadrature<dim == 0 ? 0 : dim - 1>

inherited

Define an alias for a quadrature that acts on an object of one dimension less. For cells, this would then be a face quadrature. A sub quadrature of a 0-dimensional quadrature is defined as still being 0-dimensional.

Definition at line 94 of file quadrature.h.

Constructor & Destructor Documentation

◆ QSimplex()

template<int dim>

QSimplex< dim >::QSimplex ( const Quadrature< dim > & quad )

Construct a quadrature that only contains the points that are in the lower left reference simplex.

Parameters

[in] quad The input quadrature.

Definition at line 1205 of file quadrature_lib.cc.

Member Function Documentation

◆ compute_affine_transformation()

template<int dim>

Quadrature< dim > QSimplex< dim >::compute_affine_transformation ( const std::array< Point< dim >, dim+1 > & vertices ) const

Return an affine transformation of this quadrature, that can be used to integrate on the simplex identified by vertices.

Both the quadrature point locations and the weights are transformed, so that you can effectively use the resulting quadrature to integrate on the simplex.

The transformation is defined as

\[ x = v_0 + B \hat x \]

where the matrix \(B\) is given by \(B_{ij} = v[j][i]-v[0][i]\).

The weights are scaled with the absolute value of the determinant of \(B\), that is \(J \dealcoloneq |\text{det}(B)|\). If \(J\) is zero, an empty quadrature is returned. This may happen, in two dimensions, if the three vertices are aligned, or in three dimensions if the four vertices are on the same plane.

Parameters

[in] vertices The vertices of the simplex you wish to integrate on

Returns: A quadrature object that can be used to integrate on the simplex

Definition at line 1231 of file quadrature_lib.cc.

◆ operator==()

template<int dim>

bool Quadrature< dim >::operator== ( const Quadrature< dim > & p ) const

inherited

Test for equality of two quadratures.

Definition at line 304 of file quadrature.cc.

◆ initialize()

template<int dim>

void Quadrature< dim >::initialize	(	const std::vector< Point< dim > > &	points,
		const std::vector< double > &	weights
	)

inherited

Set the quadrature points and weights to the values provided in the arguments.

Definition at line 52 of file quadrature.cc.

◆ size()

template<int dim>

unsigned int Quadrature< dim >::size ( ) const

inherited

Number of quadrature points.

◆ point()

template<int dim>

const Point< dim > & Quadrature< dim >::point ( const unsigned int i ) const

inherited

Return the ith quadrature point.

◆ get_points()

template<int dim>

const std::vector< Point< dim > > & Quadrature< dim >::get_points ( ) const

inherited

Return a reference to the whole array of quadrature points.

◆ weight()

template<int dim>

double Quadrature< dim >::weight ( const unsigned int i ) const

inherited

Return the weight of the ith quadrature point.

◆ get_weights()

template<int dim>

const std::vector< double > & Quadrature< dim >::get_weights ( ) const

inherited

Return a reference to the whole array of weights.

◆ memory_consumption()

template<int dim>

std::size_t Quadrature< dim >::memory_consumption

inherited

Determine an estimate for the memory consumption (in bytes) of this object.

Definition at line 313 of file quadrature.cc.

◆ serialize()

template<int dim>

template<class Archive >

void Quadrature< dim >::serialize	(	Archive &	ar,
		const unsigned int	version
	)

inherited

Write or read the data of this object to or from a stream for the purpose of serialization using the BOOST serialization library.

◆ is_tensor_product()

template<int dim>

bool Quadrature< dim >::is_tensor_product ( ) const

inherited

This function returns true if the quadrature object is a tensor product of one-dimensional formulas and the quadrature points are sorted lexicographically.

◆ get_tensor_basis()

template<int dim>

std::conditional< dim==1, std::array< Quadrature< 1 >, dim >, conststd::array< Quadrature< 1 >, dim > & >::type Quadrature< dim >::get_tensor_basis

inherited

In case the quadrature formula is a tensor product, this function returns the dim one-dimensional basis objects. Otherwise, calling this function is not allowed.

For dim equal to one, we can not return the std::array as a const reference and have to return it by value. In this case, the array will always contain a single element (this).

Note: The actual return type of this function is
std::conditional<dim == 1,

std::array<Quadrature<1>, dim>,

const std::array<Quadrature<1>, dim> &>::type

The type is abbreviated in the online documentation to improve readability of this page.

Definition at line 325 of file quadrature.cc.

Member Data Documentation

◆ quadrature_points

template<int dim>

std::vector<Point<dim> > Quadrature< dim >::quadrature_points

protectedinherited

List of quadrature points. To be filled by the constructors of derived classes.

Definition at line 290 of file quadrature.h.

◆ weights

template<int dim>

std::vector<double> Quadrature< dim >::weights

protectedinherited

List of weights of the quadrature points. To be filled by the constructors of derived classes.

Definition at line 296 of file quadrature.h.

◆ is_tensor_product_flag

template<int dim>

bool Quadrature< dim >::is_tensor_product_flag

protectedinherited

Indicates if this object represents quadrature formula that is a tensor product of one-dimensional formulas. This flag is set if dim==1 or the constructors taking a Quadrature<1> (and possibly a Quadrature<dim-1> object) is called. This implies that the quadrature points are sorted lexicographically.

Definition at line 305 of file quadrature.h.

◆ tensor_basis

template<int dim>

std::unique_ptr<std::array<Quadrature<1>, dim> > Quadrature< dim >::tensor_basis

protectedinherited

Stores the one-dimensional tensor basis objects in case this object can be represented by a tensor product.

Definition at line 311 of file quadrature.h.

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

include/deal.II/base/quadrature_lib.h
source/base/quadrature_lib.cc

Public Types

Public Member Functions

Protected Attributes

Subscriptor functionality

Detailed Description

Member Typedef Documentation

◆ SubQuadrature

Constructor & Destructor Documentation

◆ QSimplex()

Member Function Documentation

◆ compute_affine_transformation()

◆ operator==()

◆ initialize()

◆ size()

◆ point()

◆ get_points()

◆ weight()

◆ get_weights()

◆ memory_consumption()

◆ serialize()

◆ is_tensor_product()

◆ get_tensor_basis()

Member Data Documentation

◆ quadrature_points

◆ weights

◆ is_tensor_product_flag

◆ tensor_basis