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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 provide the same high value within each of the two groups. If pro-cesses processes
       cesses 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  collec-tive collective
       tive 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







Open MPI 1.2                                   September 2006                  MPI_Intercomm_merge(3OpenMPI)