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mpi_comm_test_inter(3openmpi) [osx man page]

MPI_Comm_test_inter(3OpenMPI)											     MPI_Comm_test_inter(3OpenMPI)

NAME
MPI_Comm_test_inter - Tests to see if a comm is an intercommunicator. SYNTAX
C Syntax #include <mpi.h> int MPI_Comm_test_inter(MPI_Comm comm, int *flag) Fortran Syntax INCLUDE 'mpif.h' MPI_COMM_TEST_INTER(COMM, FLAG, IERROR) INTEGER COMM, IERROR LOGICAL FLAG C++ Syntax #include <mpi.h> bool Comm::Is_inter() const INPUT PARAMETER
comm Communicator (handle). OUTPUT PARAMETERS
flag (Logical.) IERROR Fortran only: Error status (integer). DESCRIPTION
This local routine allows the calling process to determine the type of a communicator. It returns true for an intercommunicator, false for an intracommunicator. The type of communicator also affects the value returned by three other functions. When dealing with an intracommunicator (enables commu- nication within a single group), the functions listed below return the expected values, group size, group, and rank. When dealing with an inter-communicator, however, they return the following values: MPI_Comm_size Returns the size of the local group. MPI_Comm_group Returns the local group. MPI_Comm_rank Returns the rank in the local group. To return the remote group and remote group size of an inter-communicator, use the MPI_Comm_remote_group and MPI_Comm_remote_size func- tions. The operation MPI_Comm_compare is valid for intercommunicators. Both communicators must be either intra- or intercommunicators, or else MPI_UNEQUAL results. Both corresponding local and remote groups must compare correctly to get the results MPI_CONGRUENT and MPI_SIMILAR. In particular, it is possible for MPI_SIMILAR to result because either the local or remote groups were similar but not identical. The following accessors provide consistent access to the remote group of an intercommunicator: MPI_Comm_remote_size, MPI_Comm_remote_group. The intercommunicator accessors (MPI_Comm_test_inter, MPI_Comm_remote_size, MPI_Comm_remote_group) are all local operations. 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_remote_group MPI_Comm_remote_size MPI_Intercomm_create MPI_Intercomm_merge Open MPI 1.2 September 2006 MPI_Comm_test_inter(3OpenMPI)

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MPI_Comm_remote_group(3)						MPI						  MPI_Comm_remote_group(3)

NAME
MPI_Comm_remote_group - Accesses the remote group associated with the given inter-communicator SYNOPSIS
int MPI_Comm_remote_group(MPI_Comm comm, MPI_Group *group) INPUT PARAMETER
comm - Communicator (must be an intercommunicator) (handle) OUTPUT PARAMETER
group - remote group of communicator (handle) NOTES
The user is responsible for freeing the group when it is no longer needed. THREAD AND INTERRUPT SAFETY
This routine is thread-safe. This means that this routine may be safely used by multiple threads without the need for any user-provided thread locks. However, the routine is not interrupt safe. Typically, this is due to the use of memory allocation routines such as malloc or other non-MPICH runtime routines that are themselves not interrupt-safe. NOTES FOR FORTRAN
All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK ) have an additional argument ierr at the end of the argument list. ierr is an integer and has the same meaning as the return value of the routine in C. In Fortran, MPI routines are subroutines, and are invoked with the call statement. All MPI objects (e.g., MPI_Datatype , MPI_Comm ) are of type INTEGER in Fortran. ERRORS
All MPI routines (except MPI_Wtime and MPI_Wtick ) return an error value; C routines as the value of the function and Fortran routines in the last argument. Before the value is returned, the current MPI error handler is called. By default, this error handler aborts the MPI job. The error handler may be changed with MPI_Comm_set_errhandler (for communicators), MPI_File_set_errhandler (for files), and MPI_Win_set_errhandler (for RMA windows). The MPI-1 routine MPI_Errhandler_set may be used but its use is deprecated. The predefined error handler MPI_ERRORS_RETURN may be used to cause error values to be returned. Note that MPI does not guarentee that an MPI program can continue past an error; however, MPI implementations will attempt to continue whenever possible. MPI_SUCCESS - No error; MPI routine completed successfully. MPI_ERR_COMM - Invalid communicator. A common error is to use a null communicator in a call (not even allowed in MPI_Comm_rank ). SEE ALSO
MPI_Group_free LOCATION
comm_remote_group.c 11/6/2010 MPI_Comm_remote_group(3)
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