MPI_Comm_create(3OpenMPI) MPI_Comm_create(3OpenMPI)
NAME
MPI_Comm_create - Creates a new communicator.
SYNTAX
C Syntax
#include <mpi.h>
int MPI_Comm_create(MPI_Comm comm, MPI_Group group, MPI_Comm *newcomm)
Fortran Syntax
INCLUDE 'mpif.h'
MPI_COMM_CREATE(COMM, GROUP, NEWCOMM, IERROR)
INTEGER COMM, GROUP, NEW, IERROR
C++ Syntax
#include <mpi.h>
MPI::Intercomm MPI::Intercomm::Create(const Group& group) const
MPI::Intracomm MPI::Intracomm::Create(const Group& group) const
INPUT PARAMETER
comm Communicator (handle).
group Group, which is a subset of the group of comm (handle).
OUTPUT PARAMETERS
newcomm New communicator (handle).
IERROR Fortran only: Error status (integer).
DESCRIPTION
This function creates a new communicator newcomm with communication
group defined by group and a new context. The function sets newcomm to
a new communicator that spans all the processes that are in the group.
It sets newcomm to MPI_COMM_NULL for processes that are not in the
group. The call is erroneous if not all group arguments have the same
value, or if group is not a subset of the group associated with comm.
Note that the call must be executed by all processes in comm, even if
they do not belong to the new group.
NOTES
MPI_Comm_create provides a means of making a subset of processes for
the purpose of separate MIMD computation, with separate communication
space. newcomm, which is created by MPI_Comm_create, can be used in
subsequent calls to MPI_Comm_create (or other communicator construc-
tors) to further subdivide a computation into parallel sub-computa-
tions. A more general service is provided by MPI_Comm_split.
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_Comm_split(3), MPI_Intercomm_create(3)
Open MPI 1.2 September 2006 MPI_Comm_create(3OpenMPI)
Mac OS X 10.6 - Generated Thu Sep 17 20:12:53 CDT 2009