Reference documentation for deal.II version 9.4.1
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NonMatching::MeshClassifier< dim > Class Template Reference

#include <deal.II/non_matching/mesh_classifier.h>

Inheritance diagram for NonMatching::MeshClassifier< dim >:
[legend]

## Public Member Functions

template<class VectorType >
MeshClassifier (const DoFHandler< dim > &level_set_dof_handler, const VectorType &level_set)

MeshClassifier (const Triangulation< dim > &triangulation, const Function< dim > &level_set, const FiniteElement< dim > &element)

void reclassify ()

LocationToLevelSet location_to_level_set (const typename Triangulation< dim >::cell_iterator &cell) const

LocationToLevelSet location_to_level_set (const typename Triangulation< dim >::cell_iterator &cell, const unsigned int face_index) const

## Private Member Functions

void initialize ()

LocationToLevelSet determine_face_location_to_levelset (const typename Triangulation< dim >::active_cell_iterator &cell, const unsigned int face_index)

## Private Attributes

const SmartPointer< const Triangulation< dim > > triangulation

const std::unique_ptr< internal::MeshClassifierImplementation::LevelSetDescription< dim > > level_set_description

std::vector< LocationToLevelSetcell_locations

std::vector< LocationToLevelSetface_locations

std::vector< std::array< LAPACKFullMatrix< double >, GeometryInfo< dim >::faces_per_cell > > lagrange_to_bernstein_face

## Subscriptor functionality

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

std::atomic< unsigned intcounter

std::map< std::string, unsigned intcounter_map

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

const std::type_info * object_info

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

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

void check_no_subscribers () const noexcept

using map_value_type = decltype(counter_map)::value_type

using map_iterator = decltype(counter_map)::iterator

static std::mutex mutex

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

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

## Detailed Description

template<int dim>
class NonMatching::MeshClassifier< dim >

Class responsible for determining how the active cells and faces of a triangulation relate to the sign of a level set function. When calling the reclassify() function each of the active cells and faces are categorized as one of the values of LocationToLevelSet: inside, outside or intersected, depending on the sign of the level set function over the cell/face. This information is typically required in immersed/cut finite element methods, both when distributing degrees of freedom over the triangulation and when the system is assembled. The given class would then be used in the following way:

Vector<double> &level_set = ...
MeshClassifier<dim> classifier(dof_handler, level_set);
classifier.reclassify();
LocationToLevelSet location = classifier.location_to_level_set(cell);
Definition: vector.h:109

The level set function can either be described as a discrete function by a (DoFHandler, Vector)-pair or as a general Function. In the case of a discrete function, LocationToLevelSet for a given face is determined by looking at the local degrees of freedom on the face. Since the Lagrange basis functions are not positive definite, positive/negative definite dof values do not imply that the interpolated function is positive/negative definite. Thus, to classify a face this class internally transforms the local dofs to a basis spanning the same polynomial space over the face but where definite dof values imply a definite function. Currently, only the case of FE_Q-elements is implemented, where we internally change basis to FE_Bernstein. For cells, LocationToLevelSet is determined from the faces of the cell. That is, if all faces of the cell are inside/outside the LocationToLevelSet of the cell is set to inside/outside. LocationToLevelSet of the cell is set to intersected if at least one face is intersected or if its faces have different LocationToLevelSet. Note that, this procedure will incorrectly classify the cell as inside/outside, if the mesh refinement is so low that the whole zero-contour is contained in a single cell (so that none of its faces are intersected).

When the level set function is described as a Function, the level set function is locally interpolated to an FE_Q element and we proceed in the same way as for the discrete level set function.

Definition at line 109 of file mesh_classifier.h.

## ◆ MeshClassifier() [1/2]

template<int dim>
template<class VectorType >
 NonMatching::MeshClassifier< dim >::MeshClassifier ( const DoFHandler< dim > & level_set_dof_handler, const VectorType & level_set )

Constructor. Takes a level set function described as a DoFHandler and a Vector. The triangulation attached to DoFHandler is the one that will be classified.

Definition at line 315 of file mesh_classifier.cc.

## ◆ MeshClassifier() [2/2]

template<int dim>
 NonMatching::MeshClassifier< dim >::MeshClassifier ( const Triangulation< dim > & triangulation, const Function< dim > & level_set, const FiniteElement< dim > & element )

Constructor. Takes the triangulation that should be classified, a level set function described as a Function, and a scalar element that we interpolate the Function to in order to classify each cell/face.

Note
The Function and the FiniteElement must both have a single component.

Definition at line 345 of file mesh_classifier.cc.

## ◆ reclassify()

template<int dim>
 void NonMatching::MeshClassifier< dim >::reclassify

Perform the classification of the non artificial cells and faces in the triangulation.

Definition at line 363 of file mesh_classifier.cc.

## ◆ location_to_level_set() [1/2]

template<int dim>
 LocationToLevelSet NonMatching::MeshClassifier< dim >::location_to_level_set ( const typename Triangulation< dim >::cell_iterator & cell ) const

Return how the incoming cell is located relative to the level set function.

Definition at line 433 of file mesh_classifier.cc.

## ◆ location_to_level_set() [2/2]

template<int dim>
 LocationToLevelSet NonMatching::MeshClassifier< dim >::location_to_level_set ( const typename Triangulation< dim >::cell_iterator & cell, const unsigned int face_index ) const

Return how a face of the incoming cell is located relative to the level set function.

Definition at line 448 of file mesh_classifier.cc.

## ◆ initialize()

template<int dim>
 void NonMatching::MeshClassifier< dim >::initialize
private

For each element in the hp::FECollection returned by level_set_description, sets up the local transformation matrices.

Definition at line 465 of file mesh_classifier.cc.

## ◆ determine_face_location_to_levelset()

template<int dim>
 LocationToLevelSet NonMatching::MeshClassifier< dim >::determine_face_location_to_levelset ( const typename Triangulation< dim >::active_cell_iterator & cell, const unsigned int face_index )
private

Computes how the face with the given index on the incoming cell is located relative to the level set function.

Definition at line 400 of file mesh_classifier.cc.

## ◆ triangulation

template<int dim>
 const SmartPointer > NonMatching::MeshClassifier< dim >::triangulation
private

Pointer to the triangulation that should be classified.

Definition at line 176 of file mesh_classifier.h.

## ◆ level_set_description

template<int dim>
 const std::unique_ptr< internal::MeshClassifierImplementation::LevelSetDescription > NonMatching::MeshClassifier< dim >::level_set_description
private

Pointer to an object that describes what we need to know about the level set function. The underlying object will be of different type depending on whether the level set function is discrete (DoFHandler, Vector) or described by a Function.

Definition at line 186 of file mesh_classifier.h.

## ◆ cell_locations

template<int dim>
 std::vector NonMatching::MeshClassifier< dim >::cell_locations
private

A vector that stores how each active cell is located relative to the level set function, based on the cells active index.

Definition at line 192 of file mesh_classifier.h.

## ◆ face_locations

template<int dim>
 std::vector NonMatching::MeshClassifier< dim >::face_locations
private

A vector that stores how each active face is located relative to the level set function, based on the face's global index.

Definition at line 198 of file mesh_classifier.h.

## ◆ lagrange_to_bernstein_face

template<int dim>
 std::vector< std::array, GeometryInfo::faces_per_cell> > NonMatching::MeshClassifier< dim >::lagrange_to_bernstein_face
private

For each element in the hp::FECollection returned by the LevelSetDescription, and for each local face, this vector stores a transformation matrix to a basis where positive/negative definite face dofs implies that the underlying function is positive/negative definite over the face.

Definition at line 209 of file mesh_classifier.h.

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