mpi_group_difference(3openmpi) [osx man page]

MPI_Group_difference(3OpenMPI)											    MPI_Group_difference(3OpenMPI)

NAME

       MPI_Group_difference  - Makes a group from the difference of two groups.

SYNTAX

C Syntax
       #include <mpi.h>
       int MPI_Group_difference(MPI_Group group1, MPI_Group group2,
	    MPI_Group *newgroup)

Fortran Syntax
       INCLUDE 'mpif.h'
       MPI_GROUP_DIFFERENCE(GROUP1, GROUP2, NEWGROUP, IERROR)
	    INTEGER   GROUP1, GROUP2, NEWGROUP, IERROR

C++ Syntax
       #include <mpi.h>
       static Group Group::Difference(const Group& group1, const Group& group2)

INPUT PARAMETERS

       group1	 First group (handle).

       group2	 Second group (handle).

OUTPUT PARAMETERS

       newgroup  Difference group (handle).

       IERROR	 Fortran only: Error status (integer).

DESCRIPTION

       The set-like operations are defined as follows:

	 o    union -- All elements of the first group (group1), followed by all elements of second group (group2) that are not in the first group

	 o    intersect -- all elements of the first group that are also in the second group, ordered as in first group

	 o    difference -- all elements of the first group that are not in the second group, ordered as in the first group

       Note that for these operations the order of processes in the output group is determined primarily by order in the first group (if possible)
       and then, if necessary, by order in the second group. Neither union nor intersection are commutative, but both are associative.

       The new group can be empty, that is, equal to MPI_GROUP_EMPTY.

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_Group_free

Open MPI 1.2							  September 2006				    MPI_Group_difference(3OpenMPI)

MPI_Group_difference(3) 						MPI						   MPI_Group_difference(3)

NAME

       MPI_Group_difference -  Makes a group from the difference of two groups

SYNOPSIS

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

INPUT PARAMETERS

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

OUTPUT PARAMETER

       newgroup
	      - difference group (handle)

NOTES

       The generated group containc 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

LOCATION

       group_difference.c

								     11/6/2010						   MPI_Group_difference(3)