MPI communicator data and helpers. More...

#include <comm.hh>

Public Member Functions
	comm (MPI_Comm comm=MPI_COMM_WORLD)
	Create a new comm object and uses 'MPI_COMM_WORLD' as the communicator. More...

void	set (MPI_Comm comm)
	Change communicator to an existing one. More...

comm	create (MPI_Group group)
	Create new communicator based on color/key. More...

comm	split (int color, int key)
	Create new communicator based on color/key. More...

void	free ()
	Destroy communicator.

void	finalize ()
	Shut down MPI.

void	printf (int rank, const char *fmt,...) const
	Helper wrapper around the C standard I/O 'printf()' function. Conceptually similar to guarding a normal 'printf()' function with a check for 'rank==rank()'. More...

void	info () const
	Print some brief information about the MPI communicator. The printing is done by rank 0.

bool	rank0 () const
	Check if the executing process is rank 0.

std::vector< int >	jid (const int n) const

void	barrier () const
	Execute a barrier.


template<typename T >
void	send (int n, const T *data, int dest, int tag=0) const
	Point-to-point send. Should be matched by a corresponding 'recv' call. More...

template<typename T >
void	isend (int n, const T *data, int dest, int tag=0) const


template<typename T >
void	recv (int n, T *data, int source, int tag=0) const
	Point-to-point receive. Should be matched by a corresponding 'send' call. More...

template<typename T >
void	irecv (int n, T *data, int source, int tag=0) const


template<typename T >
void	allreduce (int n, T *data, MPI_Op op=MPI_SUM) const
	Sum reduce operation across all processes in the MPI communicator. More...


template<typename T >
void	reduce (int n, T *data, MPI_Op op=MPI_SUM, int root=0) const
	Sum reduce operation across all processes in the MPI communicator. More...


template<typename T >
void	bcast (int n, T *data, int root) const
	Broadcast. More...


MPI_Comm	get_comm () const

int	rank () const
	Calling process rank (0-based index) in the MPI communicator.

int	size () const
	Total number of ranks in the MPI communicator. The same across all ranks.

int	localrank () const
	Calling process rank (0-based index) in within the node.

int	localsize () const
	Total number of ranks within the node. Can vary across nodes.

Protected Attributes
MPI_Comm	_comm

int	_rank

int	_size

int	_localrank

int	_localsize

Detailed Description

MPI communicator data and helpers.

Constructor & Destructor Documentation

◆ comm()

fml::comm::comm ( MPI_Comm comm = MPI_COMM_WORLD )

inline

Create a new comm object and uses 'MPI_COMM_WORLD' as the communicator.

Parameters

[in] comm An MPI communicator. Default is MPI_COMM_WORLD.

Member Function Documentation

◆ allreduce()

template<typename T >

void fml::comm::allreduce	(	int	n,
		T *	data,
		MPI_Op	op = `MPI_SUM`
	)		const

inline

Sum reduce operation across all processes in the MPI communicator.

Parameters

[in]	n	Number of elemends of 'data'.
[in,out]	data	The data to reduce.
[in]	op	MPI reduction operation. Default is MPI_SUM.

◆ bcast()

template<typename T >

void fml::comm::bcast	(	int	n,
		T *	data,
		int	root
	)		const

inline

Broadcast.

Parameters

[in]	n	Number of elemends of 'data'.
[in,out]	data	The data to broadcast.
[in]	root	The rank in the MPI communicator that does the broadcasting.

◆ create()

fml::comm fml::comm::create ( MPI_Group group )

inline

Create new communicator based on color/key.

Parameters

[in] group

Returns: The new communicator managed in a new comm object.

◆ get_comm()

MPI_Comm fml::comm::get_comm ( ) const

inline

The MPI communicator.

◆ jid()

std::vector< int > fml::comm::jid ( const int n ) const

inline

Parameters

[in] n The number of tasks.

Returns: A std::vector of task numbers.

Communication Details
The method has no communication.

◆ printf()

void fml::comm::printf	(	int	rank,
		const char *	fmt,
			...
	)		const

inline

Helper wrapper around the C standard I/O 'printf()' function. Conceptually similar to guarding a normal 'printf()' function with a check for 'rank==rank()'.

Parameters

[in]	rank	The process that should do the printing.
[in]	fmt	The printf format string.
[in]	...	additional arguments to printf.

◆ recv()

template<typename T >

void fml::comm::recv	(	int	n,
		T *	data,
		int	source,
		int	tag = `0`
	)		const

inline

Point-to-point receive. Should be matched by a corresponding 'send' call.

Parameters

[in]	n	Number of elements of 'data'.
[in]	data	The data to send.
[in]	source	The process source in the MPI communicator.
[in]	tag	Optional MPI tag (default=0).

◆ reduce()

template<typename T >

void fml::comm::reduce	(	int	n,
		T *	data,
		MPI_Op	op = `MPI_SUM`,
		int	root = `0`
	)		const

inline

Sum reduce operation across all processes in the MPI communicator.

Parameters

[in]	n	Number of elemends of 'data'.
[in,out]	data	The data to reduce.
[in]	root	The rank in the MPI communicator to receive the final answer.

◆ send()

template<typename T >

void fml::comm::send	(	int	n,
		const T *	data,
		int	dest,
		int	tag = `0`
	)		const

inline

Point-to-point send. Should be matched by a corresponding 'recv' call.

Parameters

[in]	n	Number of elements of 'data'.
[in]	data	The data to send.
[in]	dest	The process destination in the MPI communicator.
[in]	tag	Optional MPI tag (default=0).

◆ set()

void fml::comm::set ( MPI_Comm comm )

inline

Change communicator to an existing one.

Parameters

[in] comm An MPI communicator.

◆ split()

fml::comm fml::comm::split	(	int	color,
		int	key
	)

inline

Create new communicator based on color/key.

Parameters

[in]	color
[in]	key

Returns: The new communicator managed in a new comm object.

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

fml/src/fml/par/comm.hh

Public Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ comm()

Member Function Documentation

◆ allreduce()

◆ bcast()

◆ create()

◆ get_comm()

◆ jid()

◆ printf()

◆ recv()

◆ reduce()

◆ send()

◆ set()

◆ split()