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
- 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