mpi_intercomm_merge(3openmpi) [osx man page]

MPI_Intercomm_merge(3OpenMPI)											     MPI_Intercomm_merge(3OpenMPI)

NAME

       MPI_Intercomm_merge - Creates an intracommunicator from an intercommunicator.

SYNTAX

C Syntax
       #include <mpi.h>
       int MPI_Intercomm_merge(MPI_Comm intercomm, int high,
	    MPI_Comm *newintracomm

Fortran Syntax
       INCLUDE 'mpif.h'
       MPI_INTERCOMM_MERGE(INTERCOMM, HIGH, NEWINTRACOMM, IERROR)
	    INTEGER   INTERCOMM, NEWINTRACOMM, IERROR
	    LOGICAL   HIGH

C++ Syntax
       #include <mpi.h>
       Intracomm Intercomm::Merge(bool high) const

INPUT PARAMETERS

       intercomm Intercommunicator (type indicator).

       high	 Used to order the groups of the two intracommunicators within comm when creating the new communicator (type indicator).

OUTPUT PARAMETERS

       newintracomm
		 Created intracommunicator (type indicator).

       IERROR	 Fortran only: Error status (integer).

DESCRIPTION

       This  function  creates an intracommunicator from the union of the two groups that are associated with intercomm. All processes should pro-
       vide the same high value within each of the two groups. If processes in one group provide the value high = false and processes in the other
       group  provide the value high = true, then the union orders the "low" group before the "high" group. If all processes provide the same high
       argument, then the order of the union is arbitrary. This call is blocking and collective within the union of the two groups.

ERRORS

       Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument. C++ func-
       tions  do not return errors. If the default error handler is set to MPI::ERRORS_THROW_EXCEPTIONS, then on error the C++ exception mechanism
       will be used to throw an MPI:Exception object.

       Before the error value is returned, the current MPI error handler is called. By default, this error handler aborts the MPI job, except  for
       I/O  function  errors. The error handler may be changed with MPI_Comm_set_errhandler; the predefined error handler MPI_ERRORS_RETURN may be
       used to cause error values to be returned. Note that MPI does not guarantee that an MPI program can continue past an error.

SEE ALSO

       MPI_Intercomm_create
       MPI_Comm_free

Open MPI 1.2							  September 2006				     MPI_Intercomm_merge(3OpenMPI)

MPI_Comm_join(3OpenMPI) 												   MPI_Comm_join(3OpenMPI)

NAME

       MPI_Comm_join - Establishes communication between MPI jobs

SYNTAX

C Syntax
       #include <mpi.h>
       int MPI_Comm_join(int fd, MPI_Comm *intercomm)

Fortran Syntax
       INCLUDE 'mpif.h'
       MPI_COMM_JOIN(FD, INTERCOMM, IERROR)
	    INTEGER   FD, INTERCOMM, IERROR

C++ Syntax
       #include <mpi.h>
       MPI::Intercomm MPI::Comm::Join(const int fd)

INPUT PARAMETER

       fd	 socket file descriptor (socket).

OUTPUT PARAMETERS

       intercomm Intercommunicator between processes (handle).

       IERROR	 Fortran only: Error status (integer).

DESCRIPTION

       MPI_Comm_join creates an intercommunicator from the union of two MPI processes that are connected by a socket. fd is a file descriptor rep-
       resenting a socket of type SOCK_STREAM (a two-way reliable byte-stream connection). Nonblocking I/O and asynchronous notification via SIGIO
       must not be enabled for the socket. The socket must be in a connected state, and must be quiescent when MPI_Comm_join is called.

       MPI_Comm_join must be called by the process at each end of the socket. It does not return until both processes have called MPI_Comm_join.

NOTES

       There  are  no  MPI library calls for opening and manipulating a socket.  The socket fd can be opened using standard socket API calls.  MPI
       uses the socket to bootstrap creation of the intercommunicator, and for nothing else. Upon return, the file descriptor  will  be  open  and
       quiescent.

       In  a  multithreaded  process, the application must ensure that other threads do not access the socket while one is in the midst of calling
       MPI_Comm_join.

       The returned communicator will contain the two processes connected by the socket, and may be used to establish MPI communication with addi-
       tional processes, through the usual MPI communicator-creation mechanisms.

ERRORS

       Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument. C++ func-
       tions do not return errors. If the default error handler is set to MPI::ERRORS_THROW_EXCEPTIONS, then on error the C++ exception  mechanism
       will be used to throw an MPI:Exception object.

       Before  the error value is returned, the current MPI error handler is called. By default, this error handler aborts the MPI job, except for
       I/O function errors. The error handler may be changed with MPI_Comm_set_errhandler; the predefined error handler MPI_ERRORS_RETURN  may	be
       used to cause error values to be returned. Note that MPI does not guarantee that an MPI program can continue past an error.

       See the MPI man page for a full list of MPI error codes.

SEE ALSO

       socket(3SOCKET)
       MPI_Comm_create
       MPI_Comm_group

Open MPI 1.2							  September 2006					   MPI_Comm_join(3OpenMPI)