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MPI_Group_difference(3) man page (version 1.3.4)

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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

1.3.4                            Nov 11, 2009          MPI_Group_difference(3)

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