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MPI_Comm_create - Creates a new communicator.
#include <mpi.h>
int MPI_Comm_create(MPI_Comm comm, MPI_Group group, MPI_Comm *newcomm)
INCLUDE ’mpif.h’
MPI_COMM_CREATE(COMM, GROUP, NEWCOMM, IERROR)
INTEGER COMM, GROUP, NEW, IERROR
#include <mpi.h>
MPI::Intercomm MPI::Intercomm::Create(const Group& group) const
MPI::Intracomm MPI::Intracomm::Create(const Group& group) const
- comm
- Communicator (handle).
- group
- Group, which is a subset
of the group of comm (handle).
- newcomm
- New communicator
(handle).
- IERROR
- Fortran only: Error status (integer).
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.
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 constructors) to further subdivide a computation
into parallel sub-computations. A more general service is provided by MPI_Comm_split.
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.
MPI_Comm_split
MPI_Intercomm_create
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