Provides C++ wrapper around MPI routines. More...

#include </home/runner/work/IBAMR/IBAMR/ibtk/include/ibtk/IBTK_MPI.h>

Static Public Member Functions
static void	setCommunicator (MPI_Comm communicator)

static MPI_Comm	getCommunicator ()

static MPI_Comm	getSAMRAIWorld ()

static int	getRank ()

static int	getNodes ()

static void	barrier ()

template<typename T >
static T	minReduction (T x, int *rank_of_min=nullptr)

template<typename T >
static void	minReduction (T x, const int n=1, int rank_of_min=nullptr)

template<typename T >
static T	maxReduction (T x, int *rank_of_min=nullptr)

template<typename T >
static void	maxReduction (T x, const int n=1, int rank_of_min=nullptr)

template<typename T >
static T	sumReduction (T)

template<typename T >
static void	sumReduction (T *x, const int n=1)

static void	allToOneSumReduction (int *x, const int n, const int root=0)

template<typename T >
static T	bcast (const T x, const int root)

template<typename T >
static void	bcast (T *x, int &length, const int root)

template<typename T >
static void	send (const T *buf, const int length, const int receiving_proc_number, const bool send_length=true, int tag=0)
	This function sends an MPI message with an array to another processer. More...

static void	sendBytes (const void *buf, const int number_bytes, const int receiving_proc_number)
	This function sends an MPI message with an array of bytes (MPI_BYTES) to receiving_proc_number. More...

static int	recvBytes (void *buf, int number_bytes)
	This function receives an MPI message with an array of max size number_bytes (MPI_BYTES) from any processer. More...

template<typename T >
static void	recv (T *buf, int &length, const int sending_proc_number, const bool get_length=true, int tag=0)
	This function receives an MPI message with an array from another processer. More...

template<typename T >
static void	allGather (const T x_in, int size_in, T x_out, int size_out)

template<typename T >
static void	allGather (T x_in, T *x_out)

Detailed Description

Provides C++ wrapper around MPI routines.

The IBTK_MPI struct provides simple interfaces to common MPI routines. All function calls allow a user-provided communicator to be used.

Note that this class is a utility class to group function calls in one name space (all calls are to static functions). Thus, you should never attempt to instantiate a class of type IBTK_MPI; simply call the functions as static functions using the IBTK_MPI::function(...) syntax.

Member Function Documentation

◆ allGather()

template<typename T >

void IBTK::IBTK_MPI::allGather	(	const T *	x_in,
		int	size_in,
		T *	x_out,
		int	size_out
	)

inlinestatic

Each processor sends an array of integers or doubles to all other processors; each processor's array may differ in length. The x_out array must be pre-allocated to the correct length (this is a bit cumbersome, but is necessary to avoid the allGather function from allocating memory that is freed elsewhere). To properly preallocate memory, before calling this method, call

size_out = IBTK_MPI::sumReduction(size_in)

then allocate the x_out array.

◆ allToOneSumReduction()

void IBTK::IBTK_MPI::allToOneSumReduction	(	int *	x,
		const int	n,
		const int	root = `0`
	)

static

Perform an all-to-one sum reduction on an integer array. The final result is only available on the root processor.

◆ barrier()

void IBTK::IBTK_MPI::barrier ( )

static

Perform a global barrier across all processors.

◆ bcast()

template<typename T >

T IBTK::IBTK_MPI::bcast	(	const T	x,
		const int	root
	)

inlinestatic

Broadcast integer array from specified root processor to all other processors. For the root processor, "array" and "length" are treated as const.

◆ getCommunicator()

MPI_Comm IBTK::IBTK_MPI::getCommunicator ( )

static

Get the current MPI communicator. The default communicator is MPI_COMM_WORLD.

◆ getNodes()

int IBTK::IBTK_MPI::getNodes ( )

static

Return the number of processors (nodes).

◆ getRank()

int IBTK::IBTK_MPI::getRank ( )

static

Return the processor rank (identifier) from 0 through the number of processors minus one.

◆ getSAMRAIWorld()

MPI_Comm IBTK::IBTK_MPI::getSAMRAIWorld ( )

static

Get SAMRAI World communicator.

◆ maxReduction()

template<typename T >

T IBTK::IBTK_MPI::maxReduction	(	T	x,
		int *	rank_of_min = `nullptr`
	)

inlinestatic

Perform a max reduction on a data structure of type double, int, or float. Each processor contributes an array of values and element-wise max is returned in the same array. If the rank_of_max is not null, the rank of which processor the max is located is stored in the array.

◆ minReduction()

template<typename T >

T IBTK::IBTK_MPI::minReduction	(	T	x,
		int *	rank_of_min = `nullptr`
	)

inlinestatic

Perform a min reduction on a data structure of type double, int, or float. Each processor contributes an array of values and element-wise min is returned in the same array. If the rank_of_min is not null, the rank of which processor the min is located is stored in the array.

◆ recv()

template<typename T >

void IBTK::IBTK_MPI::recv	(	T *	buf,
		int &	length,
		const int	sending_proc_number,
		const bool	get_length = `true`,
		int	tag = `0`
	)

inlinestatic

This function receives an MPI message with an array from another processer.

If this processor knows in advance the length of the array, use "get_length = false;" otherwise, the sending processor will first send the length of the array, then send the data. This call must be paired with a matching call to IBTK_MPI::send.

Parameters

buf	Pointer to a valid type array buffer with capacity of length integers.
length	Maximum number of integers that can be stored in buf.
sending_proc_number	Processor number of sender.
get_length	Optional boolean argument specifiying if we first need to send a message to determine the array size. Default value is true.
tag	Optional integer argument specifying a tag which must be matched by the tag of the incoming message. Default tag is 0.

◆ recvBytes()

int IBTK::IBTK_MPI::recvBytes	(	void *	buf,
		int	number_bytes
	)

static

This function receives an MPI message with an array of max size number_bytes (MPI_BYTES) from any processer.

This call must be paired with a matching call to IBTK_MPI::sendBytes.

This function returns the processor number of the sender.

Parameters

buf	Void pointer to a buffer of size number_bytes bytes.
number_bytes	Integer number specifing size of buf in bytes.

◆ send()

template<typename T >

void IBTK::IBTK_MPI::send	(	const T *	buf,
		const int	length,
		const int	receiving_proc_number,
		const bool	send_length = `true`,
		int	tag = `0`
	)

inlinestatic

This function sends an MPI message with an array to another processer.

If the receiving processor knows in advance the length of the array, use "send_length = false;" otherwise, this processor will first send the length of the array, then send the data. This call must be paired with a matching call to IBTK_MPI::recv.

Parameters

buf	Pointer to a valid type array buffer with length integers.
length	Number of integers in buf that we want to send.
receiving_proc_number	Receiving processor number.
send_length	Optional boolean argument specifiying if we first need to send a message with the array size. Default value is true.
tag	Optional integer argument specifying an integer tag to be sent with this message. Default tag is 0.

◆ sendBytes()

void IBTK::IBTK_MPI::sendBytes	(	const void *	buf,
		const int	number_bytes,
		const int	receiving_proc_number
	)

static

This function sends an MPI message with an array of bytes (MPI_BYTES) to receiving_proc_number.

This call must be paired with a matching call to IBTK_MPI::recvBytes.

Parameters

buf	Void pointer to an array of number_bytes bytes to send.
number_bytes	Integer number of bytes to send.
receiving_proc_number	Receiving processor number.

◆ setCommunicator()

void IBTK::IBTK_MPI::setCommunicator ( MPI_Comm communicator )

static

Set the communicator that is used for the MPI communication routines. The default communicator is MPI_COMM_WORLD.

◆ sumReduction()

template<typename T >

T IBTK::IBTK_MPI::sumReduction ( T x )

inlinestatic

Perform a sum reduction on a data structure of type double, int, or float. Each processor contributes an array of values and element-wise sum is returned in the same array.

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

/home/runner/work/IBAMR/IBAMR/ibtk/include/ibtk/IBTK_MPI.h
/home/runner/work/IBAMR/IBAMR/ibtk/include/ibtk/private/IBTK_MPI-inl.h
/home/runner/work/IBAMR/IBAMR/ibtk/src/utilities/IBTK_MPI.cpp

Static Public Member Functions

Detailed Description

Member Function Documentation

◆ allGather()

◆ allToOneSumReduction()

◆ barrier()

◆ bcast()

◆ getCommunicator()

◆ getNodes()

◆ getRank()

◆ getSAMRAIWorld()

◆ maxReduction()

◆ minReduction()

◆ recv()

◆ recvBytes()

◆ send()

◆ sendBytes()

◆ setCommunicator()

◆ sumReduction()