Utilities::MPI::ConsensusAlgorithms::PEX< T1, T2 > Class Template Reference

#include <deal.II/base/mpi_consensus_algorithms.h>

Inheritance diagram for Utilities::MPI::ConsensusAlgorithms::PEX< T1, T2 >:

Public Member Functions
	PEX (Process< T1, T2 > &process, const MPI_Comm &comm)
virtual	~PEX ()=default
virtual void	run () override
Public Member Functions inherited from Utilities::MPI::ConsensusAlgorithms::Interface< T1, T2 >
	Interface (Process< T1, T2 > &process, const MPI_Comm &comm)
virtual	~Interface ()=default

Private Member Functions
void	answer_requests (int index)
unsigned int	start_communication ()
void	clean_up_and_end_communication ()

Private Attributes
std::vector< unsigned int >	targets
std::vector< unsigned int >	sources
std::vector< std::vector< T1 > >	send_buffers
std::vector< std::vector< T2 > >	recv_buffers
std::vector< MPI_Request >	send_and_recv_buffers
std::vector< std::vector< T2 > >	requests_buffers
std::vector< MPI_Request >	requests_answers

Additional Inherited Members
Protected Attributes inherited from Utilities::MPI::ConsensusAlgorithms::Interface< T1, T2 >
Process< T1, T2 > &	process
const MPI_Comm &	comm
const unsigned int	my_rank
const unsigned int	n_procs

Detailed Description

template<typename T1, typename T2>
class Utilities::MPI::ConsensusAlgorithms::PEX< T1, T2 >

This class implements a concrete algorithm for the ConsensusAlgorithms::Interface base class, using a two step approach. In the first step the source ranks are determined and in the second step a static sparse data exchange is performed.

Note

In contrast to NBX, this class splits the same task into two distinct steps. In the first step, all processes are identified who want to send a request to this process. In the second step, the data is exchanged. However, since - in the second step - now it is clear how many requests have to be answered, i.e. when this process can stop waiting for requests, no IBarrier is needed.

The function Utilities::MPI::compute_point_to_point_communication_pattern() is used to determine the source processes, which implements a PEX-algorithm from Hoefner et al., "Scalable Communication Protocols for Dynamic Sparse Data Exchange".

Template Parameters

T1	The type of the elements of the vector to be sent.
T2	The type of the elements of the vector to be received.

Author

Peter Munch, 2019

Definition at line 367 of file mpi_consensus_algorithms.h.

Constructor & Destructor Documentation

PEX()

template<typename T1 , typename T2 >

Utilities::MPI::ConsensusAlgorithms::PEX< T1, T2 >::PEX	(	Process< T1, T2 > &	process,
		const MPI_Comm &	comm
	)

Constructor.

Parameters

process	Process to be run during consensus algorithm.
comm	MPI Communicator

~PEX()

template<typename T1 , typename T2 >

virtual Utilities::MPI::ConsensusAlgorithms::PEX< T1, T2 >::~PEX ( )

virtualdefault

Destructor.

Member Function Documentation

run()

template<typename T1 , typename T2 >

virtual void Utilities::MPI::ConsensusAlgorithms::PEX< T1, T2 >::run ( )

overridevirtual

Run consensus algorithm.

Implements Utilities::MPI::ConsensusAlgorithms::Interface< T1, T2 >.

answer_requests()

template<typename T1 , typename T2 >

void Utilities::MPI::ConsensusAlgorithms::PEX< T1, T2 >::answer_requests ( int  index )

private

The ith request message from another rank has been received: process the request and send an answer.

start_communication()

template<typename T1 , typename T2 >

unsigned int Utilities::MPI::ConsensusAlgorithms::PEX< T1, T2 >::start_communication ( )

private

Start to send all requests via ISend and post IRecvs for the incoming answer messages.

clean_up_and_end_communication()

template<typename T1 , typename T2 >

void Utilities::MPI::ConsensusAlgorithms::PEX< T1, T2 >::clean_up_and_end_communication ( )

private

After all answers have been exchanged, the MPI data structures can be freed and the received answers can be processed.

Member Data Documentation

targets

template<typename T1 , typename T2 >

std::vector<unsigned int> Utilities::MPI::ConsensusAlgorithms::PEX< T1, T2 >::targets

private

List of ranks of processes this processes wants to send a request to.

Definition at line 394 of file mpi_consensus_algorithms.h.

sources

template<typename T1 , typename T2 >

std::vector<unsigned int> Utilities::MPI::ConsensusAlgorithms::PEX< T1, T2 >::sources

private

List of ranks of processes wanting to send a request to this process.

Definition at line 399 of file mpi_consensus_algorithms.h.

send_buffers

template<typename T1 , typename T2 >

std::vector<std::vector<T1> > Utilities::MPI::ConsensusAlgorithms::PEX< T1, T2 >::send_buffers

private

Buffers for sending requests.

Definition at line 406 of file mpi_consensus_algorithms.h.

recv_buffers

template<typename T1 , typename T2 >

std::vector<std::vector<T2> > Utilities::MPI::ConsensusAlgorithms::PEX< T1, T2 >::recv_buffers

private

Buffers for receiving answers to requests.

Definition at line 411 of file mpi_consensus_algorithms.h.

send_and_recv_buffers

template<typename T1 , typename T2 >

std::vector<MPI_Request> Utilities::MPI::ConsensusAlgorithms::PEX< T1, T2 >::send_and_recv_buffers

private

Requests for sending requests and receiving answers to requests.

Definition at line 416 of file mpi_consensus_algorithms.h.

requests_buffers

template<typename T1 , typename T2 >

std::vector<std::vector<T2> > Utilities::MPI::ConsensusAlgorithms::PEX< T1, T2 >::requests_buffers

private

Buffers for sending answers to requests.

Definition at line 421 of file mpi_consensus_algorithms.h.

requests_answers

template<typename T1 , typename T2 >

std::vector<MPI_Request> Utilities::MPI::ConsensusAlgorithms::PEX< T1, T2 >::requests_answers

private

Requests for sending answers to requests.

Definition at line 426 of file mpi_consensus_algorithms.h.

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

• include/deal.II/base/mpi_consensus_algorithms.h