MPI_Group_intersection(3)						MPI						 MPI_Group_intersection(3)

NAME

       MPI_Group_intersection -  Produces a group as the intersection of two existing groups

SYNOPSIS

       int MPI_Group_intersection(MPI_Group group1, MPI_Group group2, MPI_Group *newgroup)

INPUT PARAMETERS

       group1 - first group (handle)
       group2 - second group (handle)

OUTPUT PARAMETER

       newgroup
	      - intersection group (handle)

NOTES

       The output group contains those processes that are in both group1 and 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

LOCATION

       group_intersection.c

								     11/6/2010						 MPI_Group_intersection(3)