DeinoMPI

The Great and Terrible implementation of MPI-2

function index

MPI_Group_difference

Makes a group from the difference of two groups
int MPI_Group_difference(
  MPI_Group group1,
  MPI_Group group2,
  MPI_Group *newgroup
);

Parameters

group1
[in] first group (handle)
group2
[in] second group (handle)
newgroup
[out] difference group (handle)

Remarks

The generated group contains the members of group1 that are not in group2.

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_GROUP
Null or invalid group passed to function.
MPI_ERR_INTERN
This error is returned when some part of the MPICH implementation is unable to acquire memory.

See Also

MPI_Group_free

Example Code

The following sample code illustrates MPI_Group_difference.

Insert code here.