Topology Class Reference

Topology stores the topology of a mesh, consisting of mesh entities and connectivity (incidence relations for the mesh entities). More...

#include <Topology.h>

Public Member Functions
	Topology (MPI_Comm comm, std::vector< CellType > type)
	Create empty mesh topology.
	Topology (const Topology &topology)=default
	Copy constructor.
	Topology (Topology &&topology)=default
	Move constructor.
	~Topology ()=default
	Destructor.
Topology &	operator= (const Topology &topology)=delete
	Assignment.
Topology &	operator= (Topology &&topology)=default
	Assignment.
int	dim () const noexcept
	Return the topological dimension of the mesh.
void	set_entity_group_offsets (int dim, const std::vector< std::int32_t > &offsets)
	Set the offsets for each group of entities of a particular dimension. See entity_group_offsets.
const std::vector< std::int32_t > &	entity_group_offsets (int dim) const
	Get the offsets for each group of entities of a particular dimension.
void	set_index_map (int dim, std::shared_ptr< const common::IndexMap > map)
	Set the IndexMap for dimension dim.
std::shared_ptr< const common::IndexMap >	index_map (int dim) const
	Get the IndexMap that described the parallel distribution of the mesh entities.
std::shared_ptr< const graph::AdjacencyList< std::int32_t > >	connectivity (int d0, int d1) const
	Return connectivity from entities of dimension d0 to entities of dimension d1.
void	set_connectivity (std::shared_ptr< graph::AdjacencyList< std::int32_t > > c, int d0, int d1)
	Set connectivity for given pair of topological dimensions.
const std::vector< std::uint32_t > &	get_cell_permutation_info () const
	Returns the permutation information.
const std::vector< std::uint8_t > &	get_facet_permutations () const
	Get the permutation number to apply to a facet.
std::vector< CellType >	cell_types () const noexcept
	Cell type.
std::int32_t	create_entities (int dim)
	Create entities of given topological dimension.
void	create_connectivity (int d0, int d1)
	Create connectivity between given pair of dimensions, d0 -> d1.
void	create_entity_permutations ()
	Compute entity permutations and reflections.
const std::vector< std::int32_t > &	interprocess_facets () const
	List of inter-process facets, if facet topology has been computed.
MPI_Comm	comm () const
	Mesh MPI communicator.

Public Attributes
std::vector< std::int64_t >	original_cell_index
	Original cell index.

Detailed Description

Topology stores the topology of a mesh, consisting of mesh entities and connectivity (incidence relations for the mesh entities).

A mesh entity e may be identified globally as a pair e = (dim, i), where dim is the topological dimension and i is the index of the entity within that topological dimension.

Todo:

Rework memory management and associated API. Currently, there is no clear caching policy implemented and no way of discarding cached data.

Member Function Documentation

cell_types()

std::vector< mesh::CellType > cell_types ( ) const

noexcept

Cell type.

Returns

Cell types that the topology is for

comm()

MPI_Comm comm

(

)

const

Mesh MPI communicator.

Returns

The communicator on which the topology is distributed

connectivity()

std::shared_ptr< const graph::AdjacencyList< std::int32_t > > connectivity	(	int	d0,
		int	d1
	)		const

Return connectivity from entities of dimension d0 to entities of dimension d1.

Parameters

[in]	d0
[in]	d1

Returns

The adjacency list that for each entity of dimension d0 gives the list of incident entities of dimension d1. Returns nullptr if connectivity has not been computed.

create_connectivity()

void create_connectivity	(	int	d0,
		int	d1
	)

Create connectivity between given pair of dimensions, d0 -> d1.

Parameters

[in]	d0	Topological dimension
[in]	d1	Topological dimension

create_entities()

std::int32_t create_entities

(

int

dim

)

Create entities of given topological dimension.

Parameters

[in]

dim

Topological dimension

Returns

Number of newly created entities, returns -1 if entities already existed

entity_group_offsets()

const std::vector< std::int32_t > & entity_group_offsets

(

int

dim

)

const

Get the offsets for each group of entities of a particular dimension.

The topology may consist of more than one cell type or facet type. In that case, the cells of the same types are grouped together in blocks, firstly for regular cells, then repeated for ghost cells. For example, a mesh with two triangles, three quads and no ghosts would have offsets: 0, 2, 5, 5, 5. A mesh with twenty tetrahedra and two ghost tetrahedra has offsets: 0, 20, 22.

Parameters

dim	Dimension of the entities

Returns

The offsets

get_facet_permutations()

const std::vector< std::uint8_t > & get_facet_permutations

(

)

const

Get the permutation number to apply to a facet.

The permutations are numbered so that:

• n % 2 gives the number of reflections to apply
• n // 2 gives the number of rotations to apply

Each column of the returned array represents a cell, and each row a facet of that cell.

Returns

The permutation number

Note

An exception is raised if the permutations have not been computed

index_map()

std::shared_ptr< const common::IndexMap > index_map

(

int

dim

)

const

Get the IndexMap that described the parallel distribution of the mesh entities.

Parameters

[in]

dim

Topological dimension

Returns

Index map for the entities of dimension dim. Returns nullptr if index map has not been set.

set_connectivity()

void set_connectivity	(	std::shared_ptr< graph::AdjacencyList< std::int32_t > >	c,
		int	d0,
		int	d1
	)

Set connectivity for given pair of topological dimensions.

Todo:

Merge with set_index_map

set_entity_group_offsets()

void set_entity_group_offsets	(	int	dim,
		const std::vector< std::int32_t > &	offsets
	)

Set the offsets for each group of entities of a particular dimension. See entity_group_offsets.

Parameters

dim	Dimension of the entities
offsets	The offsets

set_index_map()

void set_index_map	(	int	dim,
		std::shared_ptr< const common::IndexMap >	map
	)

Set the IndexMap for dimension dim.

Todo:

Merge with set_connectivity

Warning

This is experimental and likely to change

---

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

• /__w/dolfinx/dolfinx/cpp/dolfinx/mesh/Topology.h
• /__w/dolfinx/dolfinx/cpp/dolfinx/mesh/Topology.cpp