WrapMPI Namespace Reference

Namespace to correclty wrap MPI C API for modern C++. More...

Namespaces
namespace	Async

Classes
class	HostIterationPayload
	Represents the payload of data on the host side for an iteration. More...
class	IterationPayload
	Represents the payload of data exchanged during an iteration. More...

Concepts
concept	POD_t

Enumerations
enum class	SIGNALS : char { STOP , RUN , NOP , DUMP }

Functions
template<POD_t DataType>
static int	_send_unsafe (DataType *buf, size_t buf_size, size_t dest, size_t tag=0) noexcept
	Sends raw data to a destination in an unsafe manner.
template<POD_t DataType>
int	send (DataType data, size_t dest, size_t tag=0)
	Sends a single instance of data to a destination.
template<POD_t DataType>
int	send_v (std::span< const DataType > data, size_t dest, size_t tag=0, bool send_size=true) noexcept
	Sends a vector of data to a destination.
template<POD_t DataType>
std::optional< DataType >	recv (size_t src, MPI_Status *status=nullptr, size_t tag=0) noexcept
	Receives a single data item from a source.
template<POD_t DataType>
int	recv_span (std::span< DataType > buf, size_t src, MPI_Status *status=nullptr, size_t tag=0) noexcept
	Receives data into a span buffer.
template<POD_t DataType>
DataType	try_recv (size_t src, MPI_Status *status=nullptr, size_t tag=0)
	Attempts to receive a single data item from a source.
template<POD_t T>
std::optional< std::vector< T > >	recv_v (size_t source, MPI_Status *status=nullptr, size_t tag=0) noexcept
	Receives a vector of data items from a source.
template<POD_t T>
std::vector< T >	try_recv_v (size_t src, MPI_Status *status=nullptr, size_t tag=0)
	Attempts to receive a vector of data items from a source.
template<POD_t T>
int	_broadcast_unsafe (T *data, size_t _size, size_t root)
	Broadcasts raw data to all processes in an unsafe manner.
template<POD_t DataType>
int	broadcast (DataType &data, size_t root) noexcept
	Broadcasts a single data item to all processes.
template<POD_t T>
int	broadcast_span (std::span< T > data, size_t root)
	Broadcasts data stored in a span to all processes.
template<POD_t... Args>
void	host_dispatch (const ExecInfo &info, SIGNALS sign, Args &&... args)
	Dispatches a task to the host with signal and arguments.
template<POD_t T>
std::vector< T >	_gather_unsafe (T *src_data, size_t size, size_t n_rank, size_t root=0)
	Gathers raw data from all processes in an unsafe manner.
template<POD_t T>
int	_gather_unsafe_to_buffer (T *dest, T *src_data, size_t size, size_t root=0) noexcept
template<POD_t T>
std::vector< T >	gather (std::span< T > local_data, size_t n_rank, size_t root=0)
	Gathers data from all processes.
template<POD_t T>
void	gather_span (std::span< T > dest, std::span< const T > local_data, size_t root=0)
template<NumberType T>
T	gather_reduce (T data, size_t root=0)
	Gathers and reduces data to a single value.
template<NumberType T>
T	all_reduce (T data)
template<POD_t T>
std::vector< T >	gather_v (const std::vector< T > &local_data, size_t n_rank, size_t root=0)
	Gathers a vector of data from all processes.
template<POD_t T>
int	broadcast (std::vector< T > &data, size_t root, size_t current_rank)
int	critical_error () noexcept
void	barrier () noexcept
void	finalize () noexcept
bool	is_initialized () noexcept
template<typename T >
constexpr MPI_Datatype	get_type () noexcept

Detailed Description

Namespace to correclty wrap MPI C API for modern C++.

Enumeration Type Documentation

SIGNALS

enum class WrapMPI::SIGNALS : char

strong

Enumerator
STOP
RUN
NOP
DUMP

Function Documentation

_broadcast_unsafe()

template<POD_t T>

int WrapMPI::_broadcast_unsafe ( T * data, size_t _size, size_t root )

nodiscard

Broadcasts raw data to all processes in an unsafe manner.

This function sends raw data of type T from the root process to all other processes. It performs only basic safety checks

Template Parameters

T	The type of the data to broadcast.

Parameters

data	Pointer to the data to be broadcasted.
_size	The size of the data in bytes.
root	The identifier of the root process that initiates the broadcast.

Returns

An integer indicating the success or failure of the operation.

Note

Use this function with caution

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_gather_unsafe()

template<POD_t T>

std::vector< T > WrapMPI::_gather_unsafe	(	T *	src_data,
		size_t	size,
		size_t	n_rank,
		size_t	root = 0 )

Gathers raw data from all processes in an unsafe manner.

This function collects raw data of type T from all processes into a single vector on the root process. It performs no safety checks and assumes the input pointers and sizes are valid.

Template Parameters

T	The type of the data to gather.

Parameters

src_data	Pointer to the local data to be gathered.
size	The size of the local data in bytes.
n_rank	The number of processes in the communicator.
root	The identifier of the root process that gathers the data (default is 0).

Returns

A vector containing the gathered data on the root process.

Note

Use this function with caution as it performs no validation on the input.

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_gather_unsafe_to_buffer()

template<POD_t T>

int WrapMPI::_gather_unsafe_to_buffer ( T * dest, T * src_data, size_t size, size_t root = 0 )

noexcept

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_send_unsafe()

template<POD_t DataType>

static int WrapMPI::_send_unsafe ( DataType * buf, size_t buf_size, size_t dest, size_t tag = 0 )

staticnodiscardnoexcept

Sends raw data to a destination in an unsafe manner.

This function sends raw data of type DataType to the specified destination. It assumes the provided buffer and its size are valid

Template Parameters

DataType

A type satisfying the POD concept.

Parameters

buf	Pointer to the buffer containing data to send.
buf_size	The size of the buffer in bytes.
dest	The destination identifier for the data.
tag	Optional tag to identify the message (default is 0).

Returns

An integer indicating success or failure of the operation.

Note

Use this function with caution as it performs no validation on the input.

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all_reduce()

template<NumberType T>

T WrapMPI::all_reduce

(

T

data

)

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barrier()

void WrapMPI::barrier ( )

noexcept

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broadcast() [1/2]

template<POD_t DataType>

int WrapMPI::broadcast ( DataType & data, size_t root )

noexcept

Broadcasts a single data item to all processes.

This function sends a single object of type DataType from the root process to all other processes.

Template Parameters

DataType

A type satisfying the POD concept.

Parameters

data	Reference to the data to be broadcasted.
root	The identifier of the root process that initiates the broadcast.

Returns

An integer indicating the success or failure of the operation.

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broadcast() [2/2]

template<POD_t T>

int WrapMPI::broadcast	(	std::vector< T > &	data,
		size_t	root,
		size_t	current_rank )

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broadcast_span()

template<POD_t T>

int WrapMPI::broadcast_span	(	std::span< T >	data,
		size_t	root )

Broadcasts data stored in a span to all processes.

This function sends data stored in a std::span from the root process to all other processes.

Template Parameters

T	The type of the data to broadcast.

Parameters

data	A std::span containing the data to be broadcasted.
root	The identifier of the root process that initiates the broadcast.

Returns

An integer indicating the success or failure of the operation.

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critical_error()

int WrapMPI::critical_error ( )

noexcept

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finalize()

void WrapMPI::finalize ( )

noexcept

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gather()

template<POD_t T>

std::vector< T > WrapMPI::gather	(	std::span< T >	local_data,
		size_t	n_rank,
		size_t	root = 0 )

Gathers data from all processes.

This function collects data stored in a std::span from all processes into a single vector on the root process.

Template Parameters

T	The type of the data to gather.

Parameters

local_data	A std::span containing the local data to be gathered.
n_rank	The number of processes in the communicator.
root	The identifier of the root process that gathers the data (default is 0).

Returns

A vector containing the gathered data on the root process.

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gather_reduce()

template<NumberType T>

T WrapMPI::gather_reduce	(	T	data,
		size_t	root = 0 )

Gathers and reduces data to a single value.

This function collects data of type T from all processes, performs a reduction operation (sum), and returns the result to the root process.

Template Parameters

T	A type satisfying the NumberType concept.

Parameters

data	The local data to be reduced and gathered.
root	The identifier of the root process that gathers and reduces the data (default is 0).

Returns

The reduced value on the root process.

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gather_span()

template<POD_t T>

void WrapMPI::gather_span	(	std::span< T >	dest,
		std::span< const T >	local_data,
		size_t	root = 0 )

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gather_v()

template<POD_t T>

std::vector< T > WrapMPI::gather_v	(	const std::vector< T > &	local_data,
		size_t	n_rank,
		size_t	root = 0 )

Gathers a vector of data from all processes.

This function collects vectors of data from all processes into a single vector on the root process.

Template Parameters

T	The type of the data to gather.

Parameters

local_data	A vector containing the local data to be gathered.
n_rank	The number of processes in the communicator.
root	The identifier of the root process that gathers the data (default is 0).

Returns

A vector containing the gathered data on the root process.

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get_type()

template<typename T >

MPI_Datatype WrapMPI::get_type ( )

constexprnoexcept

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host_dispatch()

template<POD_t... Args>

void WrapMPI::host_dispatch	(	const ExecInfo &	info,
		SIGNALS	sign,
		Args &&...	args )

Dispatches a task to the host with signal and arguments.

This function sends execution information and arguments to the host for processing, triggered by a specific signal.

Template Parameters

Args	Variadic template types for the arguments.

Parameters

info	An ExecInfo object containing execution metadata.
sign	A SIGNALS enumeration indicating the signal to trigger the task.
args	Variadic arguments to pass to the host.

is_initialized()

bool WrapMPI::is_initialized ( )

noexcept

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recv()

template<POD_t DataType>

std::optional< DataType > WrapMPI::recv ( size_t src, MPI_Status * status = nullptr, size_t tag = 0 )

noexcept

Receives a single data item from a source.

This function attempts to receive a single object of type DataType from the specified source. If the receive operation fails, it returns an empty std::optional.

Template Parameters

DataType

A type satisfying the POD concept.

Parameters

src	The source identifier from which to receive data.
status	Optional pointer to an MPI_Status structure to retrieve message details (default is nullptr).
tag	Optional tag to filter messages (default is 0).

Returns

A std::optional containing the received data if successful, or empty if the operation fails.

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recv_span()

template<POD_t DataType>

int WrapMPI::recv_span ( std::span< DataType > buf, size_t src, MPI_Status * status = nullptr, size_t tag = 0 )

noexcept

Receives data into a span buffer.

This function attempts to receive data into the provided span buffer. The buffer must be pre-allocated and of sufficient size to hold the incoming data.

Template Parameters

DataType

A type satisfying the POD concept.

Parameters

buf	A std::span representing the destination buffer for the data.
src	The source identifier from which to receive data.
status	Optional pointer to an MPI_Status structure to retrieve message details (default is nullptr).
tag	Optional tag to filter messages (default is 0).

Returns

An integer indicating the success or failure of the operation.

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recv_v()

template<POD_t T>

std::optional< std::vector< T > > WrapMPI::recv_v ( size_t source, MPI_Status * status = nullptr, size_t tag = 0 )

noexcept

Receives a vector of data items from a source.

This function attempts to receive a vector of objects of type T from the specified source. If the receive operation fails, it returns an empty std::optional.

Template Parameters

T	The type of data to receive.

Parameters

source	The source identifier from which to receive data.
status	Optional pointer to an MPI_Status structure to retrieve message details (default is nullptr).
tag	Optional tag to filter messages (default is 0).

Returns

A std::optional containing the received vector if successful, or empty if the operation fails.

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send()

template<POD_t DataType>

int WrapMPI::send	(	DataType	data,
		size_t	dest,
		size_t	tag = 0 )

Sends a single instance of data to a destination.

This function sends a single object of type DataType to the specified destination.

Template Parameters

DataType

A type satisfying the POD concept.

Parameters

data	The data object to send.
dest	The destination identifier for the data.
tag	Optional tag to identify the message (default is 0).

Returns

An integer indicating success or failure of the operation.

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send_v()

template<POD_t DataType>

int WrapMPI::send_v ( std::span< const DataType > data, size_t dest, size_t tag = 0, bool send_size = true )

noexcept

Sends a vector of data to a destination.

This function sends a collection of objects of type DataType to the specified destination. Optionally, the size of the collection can also be transmitted.

Template Parameters

DataType

A type satisfying the POD concept.

Parameters

data	A std::span containing the data to send.
dest	The destination identifier for the data.
tag	Optional tag to identify the message (default is 0).
send_size	If true, the size of the data will be sent before the data itself (default is true).

Returns

An integer indicating success or failure of the operation.

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try_recv()

template<POD_t DataType>

DataType WrapMPI::try_recv	(	size_t	src,
		MPI_Status *	status = nullptr,
		size_t	tag = 0 )

Attempts to receive a single data item from a source.

This function attempts to receive a single object of type DataType from the specified source. If the operation fails, it throws an exception.

Template Parameters

DataType

A type satisfying the POD concept.

Parameters

src	The source identifier from which to receive data.
status	Optional pointer to an MPI_Status structure to retrieve message details (default is nullptr).
tag	Optional tag to filter messages (default is 0).

Returns

The received data item.

Exceptions

An	exception if the receive operation fails.

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try_recv_v()

template<POD_t T>

std::vector< T > WrapMPI::try_recv_v	(	size_t	src,
		MPI_Status *	status = nullptr,
		size_t	tag = 0 )

Attempts to receive a vector of data items from a source.

This function attempts to receive a vector of objects of type T from the specified source. If the operation fails, it throws an exception.

Template Parameters

T	The type of data to receive.

Parameters

src	The source identifier from which to receive data.
status	Optional pointer to an MPI_Status structure to retrieve message details (default is nullptr).
tag	Optional tag to filter messages (default is 0).

Returns

A vector containing the received data items.

Exceptions

An	exception if the receive operation fails.

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