MPI_Intercomm_merge(3)             Open MPI             MPI_Intercomm_merge(3)



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 provide
       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++
       functions 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







1.4.1                            Jan 14, 2010           MPI_Intercomm_merge(3)
