Typedefs
using	comm_type = MPI_Comm

Functions
void	initialize (int argc, char **argv)
	True if the calling process is the root (rank 0), false otherwise.

void	finalize ()
	Finalize MPI environment.

void	barrier (const comm_type &comm)
	Barrier synchronization among processes in the communicator.

void	get_info (const comm_type &comm, int &rank, int &size, bool &is_root)
	Get MPI information: rank, size, and whether the process is the root.

template<typename C >
C	allreduce_sum (C val, const MPI_Comm &comm)
	Calculate a summation over MPI communicator.

template<typename C >
std::vector< C >	allreduce_vec (const std::vector< C > &vec, const MPI_Comm &comm)
	Calculate a summation of each element of vector over MPI communicator.

template<typename C >
void	allreduce (const C sendbuf, C recvbuf, int count, MPI_Op op, const MPI_Comm &comm)
	Wrapper of MPI_Allreduce.

template<typename C >
void	sendrecv (const C sendbuf, int sendcount, int dest, int sendtag, C recvbuf, int recvcount, int source, int recvtag, const MPI_Comm &comm)
	Wrapper of MPI_Sendrecv.

template<typename C >
void	sendrecv (const std::vector< C > &send_vec, int dest, int sendtag, std::vector< C > &recv_vec, int source, int recvtag, const MPI_Comm &comm)
	Wrapper of MPI_Sendrecv for std::vector.

template<typename C >
void	alltoall (const C sendbuf, int sendcount, C recvbuf, int recvcount, const MPI_Comm &comm)
	Wrapper of MPI_Alltoall.

template<typename C >
void	alltoallv (const C sendbuf, const int sendcounts, const int sdispls, C recvbuf, const int recvcounts, const int rdispls, const MPI_Comm &comm)
	Wrapper of MPI_Alltoallv.

template<typename C >
void	bcast (C *buffer, int count, int root, const MPI_Comm &comm)
	Wrapper of MPI_Bcast.

Variables
int	rank = -1
	Type for MPI communicator.

int	size = -1
	Rank of the calling process in the communicator.

bool	is_root = false
	Number of processes in the communicator.

template<typename C >
MPI_Datatype	mpi_datatype = MPI_DATATYPE_NULL
	Template variable for MPI Datatype.

Typedef Documentation

◆ comm_type

using mptensor::mpi::comm_type = typedef MPI_Comm

Function Documentation

◆ allreduce()

template<typename C >

void mptensor::mpi::allreduce	(	const C *	sendbuf,
		C *	recvbuf,
		int	count,
		MPI_Op	op,
		const MPI_Comm &	comm
	)

inline

Wrapper of MPI_Allreduce.

Parameters

[in]	sendbuf	send buffer
[out]	recvbuf	receive buffer
[in]	count	the number in send buffer
[in]	op	Opreation
[in]	comm	MPI Communicator

◆ allreduce_sum()

template<typename C >

C mptensor::mpi::allreduce_sum	(	C	val,
		const MPI_Comm &	comm
	)

inline

Calculate a summation over MPI communicator.

Parameters

[in]	val	value to be summed.
[in]	comm	MPI communicator.

Returns: summation of val.

◆ allreduce_vec()

template<typename C >

std::vector< C > mptensor::mpi::allreduce_vec	(	const std::vector< C > &	vec,
		const MPI_Comm &	comm
	)

inline

Calculate a summation of each element of vector over MPI communicator.

Parameters

[in]	vec	vector to be summed.
[in]	comm	MPI communicator.

Returns: resulted vector.

◆ alltoall()

template<typename C >

void mptensor::mpi::alltoall	(	const C *	sendbuf,
		int	sendcount,
		C *	recvbuf,
		int	recvcount,
		const MPI_Comm &	comm
	)

inline

Wrapper of MPI_Alltoall.

Parameters

[in]	sendbuf	Starting address of send buffer.
[in]	sendcount	The number of elements to send.
[out]	recvbuf	Address of receive buffer.
[in]	recvcount	The number of elements to receive.
[in]	comm	Communicator over which data is to be exchanged.

◆ alltoallv()

template<typename C >

void mptensor::mpi::alltoallv	(	const C *	sendbuf,
		const int *	sendcounts,
		const int *	sdispls,
		C *	recvbuf,
		const int *	recvcounts,
		const int *	rdispls,
		const MPI_Comm &	comm
	)

inline

Wrapper of MPI_Alltoallv.

Parameters

[in]	sendbuf	Starting address of send buffer.
[in]	sendcounts	Integer array, where entry i specifies the number of elements to send to rank i.
[in]	sdispls	Integer array, where entry i specifies the displacement (offset from sendbuf, in units of sendtype) from which to send data to rank i.
[out]	recvbuf	Address of receive buffer.
[in]	recvcounts	Integer array, where entry j specifies the number of elements to receive from rank j.
[in]	rdispls	Integer array, where entry j specifies the displacement (offset from recvbuf, in units of recvtype) to which data from rank j should be written.
[in]	comm	Communicator over which data is to be exchanged.

◆ barrier()

void mptensor::mpi::barrier ( const comm_type & comm )

Barrier synchronization among processes in the communicator.

Parameters

comm	MPI communicator

◆ bcast()

template<typename C >

void mptensor::mpi::bcast	(	C *	buffer,
		int	count,
		int	root,
		const MPI_Comm &	comm
	)

inline

Wrapper of MPI_Bcast.

Parameters

buffer	Starting address of buffer.
count	Number of entries in buffer.
root	Rank of broadcast root.
comm	Communicator.

◆ finalize()

void mptensor::mpi::finalize ( )

Finalize MPI environment.

This function is registered to be called at exit by initialize().

◆ get_info()

void mptensor::mpi::get_info	(	const comm_type &	comm,
		int &	rank,
		int &	size,
		bool &	is_root
	)

Get MPI information: rank, size, and whether the process is the root.

Parameters

comm	MPI communicator
rank	Rank of the calling process in the communicator
size	Number of processes in the communicator
is_root	True if the calling process is the root (rank 0), false otherwise

◆ initialize()

void mptensor::mpi::initialize	(	int	argc,
		char **	argv
	)

True if the calling process is the root (rank 0), false otherwise.

Initialize MPI environment and get MPI information

Parameters

argc	Number of command-line arguments
argv	Array of command-line arguments

This function should be called before any MPI communication. It also registers the finalize function to be called at exit.

◆ sendrecv() [1/2]

template<typename C >

void mptensor::mpi::sendrecv	(	const C *	sendbuf,
		int	sendcount,
		int	dest,
		int	sendtag,
		C *	recvbuf,
		int	recvcount,
		int	source,
		int	recvtag,
		const MPI_Comm &	comm
	)

inline

Wrapper of MPI_Sendrecv.

Parameters

[in]	sendbuf	send buffer
[in]	sendcount	the number of elements to send
[in]	dest	Rank of destination
[in]	sendtag	Send tag
[out]	recvbuf	receive buffer
[in]	recvcount	the number of elements to receive
[in]	source	Rank of source
[in]	recvtag	Receive tag
[in]	comm	MPI Communicator

◆ sendrecv() [2/2]

template<typename C >

void mptensor::mpi::sendrecv	(	const std::vector< C > &	send_vec,
		int	dest,
		int	sendtag,
		std::vector< C > &	recv_vec,
		int	source,
		int	recvtag,
		const MPI_Comm &	comm
	)

inline

Wrapper of MPI_Sendrecv for std::vector.

Parameters

[in]	send_vec	send vector
[in]	dest	Rank of destination
[in]	sendtag	Send tag
[out]	recv_vec	receive vector
[in]	source	Rank of source
[in]	recvtag	Receive tag
[in]	comm	MPI Communicator

Variable Documentation

◆ is_root

bool mptensor::mpi::is_root = false

Number of processes in the communicator.

◆ mpi_datatype

template<typename C >

MPI_Datatype mptensor::mpi::mpi_datatype = MPI_DATATYPE_NULL

inline

Template variable for MPI Datatype.

◆ rank

int mptensor::mpi::rank = -1

Type for MPI communicator.

◆ size

int mptensor::mpi::size = -1

Rank of the calling process in the communicator.

Typedefs

Functions

Variables

Typedef Documentation

◆ comm_type

Function Documentation

◆ allreduce()

◆ allreduce_sum()

◆ allreduce_vec()

◆ alltoall()

◆ alltoallv()

◆ barrier()

◆ bcast()

◆ finalize()

◆ get_info()

◆ initialize()

◆ sendrecv() [1/2]

◆ sendrecv() [2/2]

Variable Documentation

◆ is_root

◆ mpi_datatype

◆ rank

◆ size