This class represents the distribution index arrays across processes. An index array is a contiguous collection of N+1 indices [0, 1, . . ., N] that are distributed across M processes. On a given process, the IndexMap stores a portion of the index set using local indices [0, 1, . . . , n], and a map from the local indices to a unique global index. More...

#include <IndexMap.h>

Public Types
enum class	Mode { insert , add }
	Mode for reverse scatter operation.

enum class	Direction { reverse , forward , symmetric }
	Edge directions of neighborhood communicator.

Public Member Functions
	IndexMap (MPI_Comm comm, std::int32_t local_size)
	Create an non-overlapping index map with local_size owned on this process. More...

	IndexMap (MPI_Comm mpi_comm, std::int32_t local_size, const std::vector< int > &dest_ranks, const std::vector< std::int64_t > &ghosts, const std::vector< int > &src_ranks)
	Create an index map with local_size owned indiced on this process. More...

	IndexMap (const IndexMap &map)=delete

	IndexMap (IndexMap &&map)=default
	Move constructor.

	~IndexMap ()=default
	Destructor.

IndexMap &	operator= (IndexMap &&map)=default
	Move assignment.

IndexMap &	operator= (const IndexMap &map)=delete

std::array< std::int64_t, 2 >	local_range () const noexcept
	Range of indices (global) owned by this process.

std::int32_t	num_ghosts () const noexcept
	Number of ghost indices on this process.

std::int32_t	size_local () const noexcept
	Number of indices owned by on this process.

std::int64_t	size_global () const noexcept
	Number indices across communicator.

const std::vector< std::int64_t > &	ghosts () const noexcept
	Local-to-global map for ghosts (local indexing beyond end of local range)

MPI_Comm	comm (Direction dir=Direction::symmetric) const
	Return a MPI communicator with attached distributed graph topology information. More...

void	local_to_global (const std::int32_t local, int n, std::int64_t global) const
	Compute global indices for array of local indices. More...

std::vector< std::int32_t >	global_to_local (const std::vector< std::int64_t > &indices) const
	Compute local indices for array of global indices. More...

std::vector< std::int64_t >	global_indices () const
	Global indices. More...

const std::vector< std::int32_t > &	shared_indices () const noexcept

std::vector< int >	ghost_owner_rank () const
	Owner rank (on global communicator) of each ghost entry.

std::map< std::int32_t, std::set< int > >	compute_shared_indices () const

void	scatter_fwd (const std::vector< std::int64_t > &local_data, std::vector< std::int64_t > &remote_data, int n) const
	Send n values for each index that is owned to processes that have the index as a ghost. The size of the input array local_data must be the same as n * size_local(). More...

void	scatter_fwd (const std::vector< std::int32_t > &local_data, std::vector< std::int32_t > &remote_data, int n) const
	Send n values for each index that is owned to processes that have the index as a ghost. The size of the input array local_data must be the same as n * size_local(). More...

std::vector< std::int64_t >	scatter_fwd (const std::vector< std::int64_t > &local_data, int n) const
	Send n values for each index that is owned to processes that have the index as a ghost. The size of the input array local_data must be the same as n * size_local(). More...

std::vector< std::int32_t >	scatter_fwd (const std::vector< std::int32_t > &local_data, int n) const
	Send n values for each index that is owned to processes that have the index as a ghost. More...

void	scatter_rev (std::vector< std::int64_t > &local_data, const std::vector< std::int64_t > &remote_data, int n, IndexMap::Mode op) const
	Send n values for each ghost index to owning to the process. More...

void	scatter_rev (std::vector< std::int32_t > &local_data, const std::vector< std::int32_t > &remote_data, int n, IndexMap::Mode op) const
	Send n values for each ghost index to owning to the process. More...

Detailed Description

This class represents the distribution index arrays across processes. An index array is a contiguous collection of N+1 indices [0, 1, . . ., N] that are distributed across M processes. On a given process, the IndexMap stores a portion of the index set using local indices [0, 1, . . . , n], and a map from the local indices to a unique global index.

Constructor & Destructor Documentation

◆ IndexMap() [1/2]

IndexMap::IndexMap	(	MPI_Comm	comm,
		std::int32_t	local_size
	)

Create an non-overlapping index map with local_size owned on this process.

Note: Collective

Parameters

[in]	comm	The MPI communicator
[in]	local_size	Local size of the IndexMap, i.e. the number of owned entries

◆ IndexMap() [2/2]

IndexMap::IndexMap	(	MPI_Comm	mpi_comm,
		std::int32_t	local_size,
		const std::vector< int > &	dest_ranks,
		const std::vector< std::int64_t > &	ghosts,
		const std::vector< int > &	src_ranks
	)

Create an index map with local_size owned indiced on this process.

Note: Collective

Parameters

[in]	mpi_comm	The MPI communicator
[in]	local_size	Local size of the IndexMap, i.e. the number of owned entries
[in]	dest_ranks	Ranks that 'ghost' indices that are owned by the calling rank. I.e., ranks that the caller will send data to when updating ghost values.
[in]	ghosts	The global indices of ghost entries
[in]	src_ranks	Owner rank (on global communicator) of each entry in `ghosts`

Member Function Documentation

◆ comm()

MPI_Comm IndexMap::comm ( Direction dir = Direction::symmetric ) const

Return a MPI communicator with attached distributed graph topology information.

Parameters

[in] dir Edge direction of communicator (forward, reverse, symmetric)

Returns: A neighborhood communicator for the specified edge direction

◆ compute_shared_indices()

std::map< std::int32_t, std::set< int > > IndexMap::compute_shared_indices ( ) const

Todo:: Aim to remove this function? If it's kept, should it work with neighborhood ranks?

Compute map from each local (owned) index to the set of ranks that have the index as a ghost

Returns: shared indices

◆ global_indices()

std::vector< std::int64_t > IndexMap::global_indices ( ) const

Global indices.

Returns: The global index for all local indices (0, 1, 2, ...) on this process, including ghosts

◆ global_to_local()

std::vector< std::int32_t > IndexMap::global_to_local ( const std::vector< std::int64_t > & indices ) const

Compute local indices for array of global indices.

Parameters

[in] indices Global indices

Returns: The local of the corresponding global index in indices. Returns -1 if the local index does not exist on this process.

◆ local_to_global()

void IndexMap::local_to_global	(	const std::int32_t *	local,
		int	n,
		std::int64_t *	global
	)		const

Compute global indices for array of local indices.

Parameters

[in]	local	Local indices
[in]	n	Number of indices
[out]	global	The global indices

◆ scatter_fwd() [1/4]

std::vector< std::int32_t > IndexMap::scatter_fwd	(	const std::vector< std::int32_t > &	local_data,
		int	n
	)		const

Send n values for each index that is owned to processes that have the index as a ghost.

Parameters

[in]	local_data	Local data associated with each owned local index to be sent to process where the data is ghosted. Size must be n * size_local().
[in]	n	Number of data items per index

Returns: Ghost data on this process received from the owning process. Size will be n * num_ghosts().

◆ scatter_fwd() [2/4]

void IndexMap::scatter_fwd	(	const std::vector< std::int32_t > &	local_data,
		std::vector< std::int32_t > &	remote_data,
		int	n
	)		const

Send n values for each index that is owned to processes that have the index as a ghost. The size of the input array local_data must be the same as n * size_local().

Parameters

[in]	local_data	Local data associated with each owned local index to be sent to process where the data is ghosted. Size must be n * size_local().
[in,out]	remote_data	Ghost data on this process received from the owning process. Size will be n * num_ghosts().
[in]	n	Number of data items per index

◆ scatter_fwd() [3/4]

std::vector< std::int64_t > IndexMap::scatter_fwd	(	const std::vector< std::int64_t > &	local_data,
		int	n
	)		const

Send n values for each index that is owned to processes that have the index as a ghost. The size of the input array local_data must be the same as n * size_local().

Parameters

[in]	local_data	Local data associated with each owned local index to be sent to process where the data is ghosted. Size must be n * size_local().
[in]	n	Number of data items per index

Returns: Ghost data on this process received from the owning process. Size will be n * num_ghosts().

◆ scatter_fwd() [4/4]

void IndexMap::scatter_fwd	(	const std::vector< std::int64_t > &	local_data,
		std::vector< std::int64_t > &	remote_data,
		int	n
	)		const

Send n values for each index that is owned to processes that have the index as a ghost. The size of the input array local_data must be the same as n * size_local().

Parameters

[in]	local_data	Local data associated with each owned local index to be sent to process where the data is ghosted. Size must be n * size_local().
[in,out]	remote_data	Ghost data on this process received from the owning process. Size will be n * num_ghosts().
[in]	n	Number of data items per index

◆ scatter_rev() [1/2]

void IndexMap::scatter_rev	(	std::vector< std::int32_t > &	local_data,
		const std::vector< std::int32_t > &	remote_data,
		int	n,
		IndexMap::Mode	op
	)		const

Send n values for each ghost index to owning to the process.

Parameters

[in,out]	local_data	Local data associated with each owned local index to be sent to process where the data is ghosted. Size must be n * size_local().
[in]	remote_data	Ghost data on this process received from the owning process. Size will be n * num_ghosts().
[in]	n	Number of data items per index
[in]	op	Sum or set received values in local_data

◆ scatter_rev() [2/2]

void IndexMap::scatter_rev	(	std::vector< std::int64_t > &	local_data,
		const std::vector< std::int64_t > &	remote_data,
		int	n,
		IndexMap::Mode	op
	)		const

Send n values for each ghost index to owning to the process.

Parameters

[in,out]	local_data	Local data associated with each owned local index to be sent to process where the data is ghosted. Size must be n * size_local().
[in]	remote_data	Ghost data on this process received from the owning process. Size will be n * num_ghosts().
[in]	n	Number of data items per index
[in]	op	Sum or set received values in local_data

◆ shared_indices()

const std::vector< std::int32_t > & IndexMap::shared_indices ( ) const

noexcept

Todo:: Reconsider name Local (owned) indices shared with neighbor processes, i.e. are ghosts on other processes

Returns: List of indices that are ghosted on other processes

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

/build/dolfinx-gH0Wrx/dolfinx-2019.2.0~git20210130.c14cb0a/cpp/dolfinx/common/IndexMap.h
/build/dolfinx-gH0Wrx/dolfinx-2019.2.0~git20210130.c14cb0a/cpp/dolfinx/common/IndexMap.cpp

Public Types

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ IndexMap() [1/2]

◆ IndexMap() [2/2]

Member Function Documentation

◆ comm()

◆ compute_shared_indices()

◆ global_indices()

◆ global_to_local()

◆ local_to_global()

◆ scatter_fwd() [1/4]

◆ scatter_fwd() [2/4]

◆ scatter_fwd() [3/4]

◆ scatter_fwd() [4/4]

◆ scatter_rev() [1/2]

◆ scatter_rev() [2/2]

◆ shared_indices()