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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
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)
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