MPIX_Barrier_init(3)

NAME
MPIX_Allgather_init, MPIX_Allgatherv_init, MPIX_Allreduce_init, MPIX_Alltoall_init, MPIX_Alltoallv_init, MPIX_Alltoallw_init, MPIX_Barrier_init, MPIX_Bcast_init, MPIX_Exscan_init, MPIX_Gather_init, MPIX_Gatherv_init, MPIX_Reduce_init, MPIX_Reduce_scatter_init, MPIX_Reduce_scatter_block_init, MPIX_Scan_init, MPIX_Scatter_init, MPIX_Scatterv_init, MPIX_Neighbor_allgather_init, MPIX_Neighbor_allgatherv_init, MPIX_Neighbor_alltoall_init, MPIX_Neighbor_alltoallv_init, MPIX_Neighbor_alltoallw_init - Builds a handle for a collective communication or neighborhood collective communication

SYNTAX

C Syntax
#include <mpi.h>
#include <mpi-ext.h>
int MPIX_Allgather_init(const void *sendbuf, int sendcount,
	MPI_Datatype sendtype, void *recvbuf, int recvcount,
	MPI_Datatype recvtype, MPI_Comm comm, MPI_Info info,
	MPI_Request *request)

int MPIX_Allgatherv_init(const void *sendbuf, int sendcount,
	MPI_Datatype sendtype, void *recvbuf, const int recvcounts[],
	const int displs[], MPI_Datatype recvtype, MPI_Comm comm,
	MPI_Info info, MPI_Request *request)

int MPIX_Allreduce_init(const void *sendbuf, void *recvbuf, int count,
	MPI_Datatype datatype, MPI_Op op, MPI_Comm comm, MPI_Info info,
	MPI_Request *request)

int MPIX_Alltoall_init(const void *sendbuf, int sendcount,
	MPI_Datatype sendtype, void *recvbuf, int recvcount,
	MPI_Datatype recvtype, MPI_Comm comm, MPI_Info info,
	MPI_Request *request)

int MPIX_Alltoallv_init(const void *sendbuf, const int sendcounts[],
	const int sdispls[], MPI_Datatype sendtype, void *recvbuf,
	const int recvcounts[], const int rdispls[], MPI_Datatype recvtype,
	MPI_Comm comm, MPI_Info info, MPI_Request *request)

int MPIX_Alltoallw_init(const void *sendbuf, const int sendcounts[],
	const int sdispls[], const MPI_Datatype sendtypes[], void *recvbuf,
	const int recvcounts[], const int rdispls[],
	const MPI_Datatype recvtypes[], MPI_Comm comm, MPI_Info info,
	MPI_Request *request)

int MPIX_Barrier_init(MPI_Comm comm, MPI_Info info,
	MPI_Request *request)

int MPIX_Bcast_init(void *buffer, int count, MPI_Datatype datatype,
	int root, MPI_Comm comm, MPI_Info info, MPI_Request *request)

int MPIX_Exscan_init(const void *sendbuf, void *recvbuf, int count,
	MPI_Datatype datatype, MPI_Op op, MPI_Comm comm, MPI_Info info,
	MPI_Request *request)

int MPIX_Gather_init(const void *sendbuf, int sendcount,
	MPI_Datatype sendtype, void *recvbuf, int recvcount,
	MPI_Datatype recvtype, int root, MPI_Comm comm, MPI_Info info,
	MPI_Request *request)

int MPIX_Gatherv_init(const void *sendbuf, int sendcount,
	MPI_Datatype sendtype, void *recvbuf, const int recvcounts[],
	const int displs[], MPI_Datatype recvtype, int root, MPI_Comm comm,
	MPI_Info info, MPI_Request *request)

int MPIX_Reduce_init(const void *sendbuf, void *recvbuf, int count,
	MPI_Datatype datatype, MPI_Op op, int root, MPI_Comm comm,
	MPI_Info info, MPI_Request *request)

int MPIX_Reduce_scatter_init(const void *sendbuf, void *recvbuf,
	const int recvcounts[], MPI_Datatype datatype, MPI_Op op,
	MPI_Comm comm, MPI_Info info, MPI_Request *request)

int MPIX_Reduce_scatter_block_init(const void *sendbuf, void *recvbuf,
	int recvcount, MPI_Datatype datatype, MPI_Op op, MPI_Comm comm,
	MPI_Info info, MPI_Request *request)

int MPIX_Scan_init(const void *sendbuf, void *recvbuf, int count,
	MPI_Datatype datatype, MPI_Op op, MPI_Comm comm, MPI_Info info,
	MPI_Request *request)

int MPIX_Scatter_init(const void *sendbuf, int sendcount,
	MPI_Datatype sendtype, void *recvbuf, int recvcount,
	MPI_Datatype recvtype, int root, MPI_Comm comm, MPI_Info info,
	MPI_Request *request)

int MPIX_Scatterv_init(const void *sendbuf, const int sendcounts[],
	const int displs[], MPI_Datatype sendtype, void *recvbuf,
	int recvcount, MPI_Datatype recvtype, int root, MPI_Comm comm,
	MPI_Info info, MPI_Request *request)

int MPIX_Neighbor_allgather_init(const void *sendbuf, int sendcount,
	MPI_Datatype sendtype, void *recvbuf, int recvcount,
	MPI_Datatype recvtype, MPI_Comm comm, MPI_Info info,
	MPI_Request *request)

int MPIX_Neighbor_allgatherv_init(const void *sendbuf, int sendcount,
	MPI_Datatype sendtype, void *recvbuf, const int recvcounts[],
	const int displs[], MPI_Datatype recvtype, MPI_Comm comm,
	MPI_Info info, MPI_Request *request)

int MPIX_Neighbor_alltoall_init(const void *sendbuf, int sendcount,
	MPI_Datatype sendtype, void *recvbuf, int recvcount,
	MPI_Datatype recvtype, MPI_Comm comm, MPI_Info info,
	MPI_Request *request)

int MPIX_Neighbor_alltoallv_init(const void *sendbuf,
	const int sendcounts[], const int sdispls[], MPI_Datatype sendtype,
	void *recvbuf, const int recvcounts[], const int rdispls[],
	MPI_Datatype recvtype, MPI_Comm comm, MPI_Info info,
	MPI_Request *request)

int MPIX_Neighbor_alltoallw_init(const void *sendbuf,
	const int sendcounts[], const MPI_Aint sdispls[],
	const MPI_Datatype sendtypes[], void *recvbuf,
	const int recvcounts[], const MPI_Aint rdispls[],
	const MPI_Datatype recvtypes[], MPI_Comm comm, MPI_Info info,
	MPI_Request *request)

DESCRIPTION
Creates a persistent communication request for a collective operation or neighborhood collective operation.

As of Nov. 2018, the feature of persistent collective communication operations and persistent collective neighborhood communication operations is planned to be included in the next MPI Standard after MPI-3.1.

    https://github.com/mpi-forum/mpi-issues/issues/25

Open MPI implements 2018 Draft Specification of the MPI standard shown in the following URL.

    https://www.mpi-forum.org/docs/drafts/mpi-2018-draft-report.pdf

The interface may still change in the standard. Therefore the prefix MPIX_ is used instead of MPI_ for these request creation routines. To start, complete, and free the created request, usual MPI routines (MPI_Start etc.) can be used.

Future versions of Open MPI will switch to the MPI_ prefix and will not require the C header file mpi-ext.h, the Fortran modules mpi_ext and mpi_f08_ext, and the Fortran header file mpif-ext.h once the MPI Standard which includes this feature is published.

EXAMPLE

    MPI_Request req;
    MPIX_Barrier_init(MPI_COMM_WORLD, MPI_INFO_NULL, &req);
    MPI_Start(&req);
    MPI_Wait(&req, MPI_STATUS_IGNORE);
    MPI_Request_free(&req);

SEE ALSO

MPI_Start
MPI_Startall
MPI_Request_free