.. _mpi_group_excl:

MPI_Group_excl
==============

.. include_body

:ref:`MPI_Group_excl` - Produces a group by reordering an existing group and
taking only unlisted members.

Syntax
------

C Syntax
^^^^^^^^

.. code:: c

   #include <mpi.h>

   int MPI_Group_excl(MPI_Group group, int n, const int ranks[],
       MPI_Group *newgroup)

Fortran Syntax
^^^^^^^^^^^^^^

.. code:: fortran

   USE MPI
   ! or the older form: INCLUDE 'mpif.h'

   MPI_GROUP_EXCL(GROUP, N, RANKS, NEWGROUP, IERROR)
       INTEGER GROUP, N, RANKS(*), NEWGROUP, IERROR

Fortran 2008 Syntax
^^^^^^^^^^^^^^^^^^^

.. code:: fortran

   USE mpi_f08

   MPI_Group_excl(group, n, ranks, newgroup, ierror)
       TYPE(MPI_Group), INTENT(IN) :: group
       INTEGER, INTENT(IN) :: n, ranks(n)
       TYPE(MPI_Group), INTENT(OUT) :: newgroup
       INTEGER, OPTIONAL, INTENT(OUT) :: ierror

Input Parameters
----------------

-  group : Group (handle).
-  n : Number of elements in array ranks (integer).
-  ranks : Array of integer ranks in group not to appear in newgroup.

Output Parameters
-----------------

-  newgroup : New group derived from above, preserving the order defined
   by group (handle).
-  IERROR : Fortran only: Error status (integer).

Description
-----------

The function :ref:`MPI_Group_excl` creates a group of processes newgroup that
is obtained by deleting from group those processes with ranks ranks[0],
... ranks[n-1]. The ordering of processes in newgroup is identical to
the ordering in group. Each of the n elements of ranks must be a valid
rank in group and all elements must be distinct; otherwise, the call is
erroneous. If n = 0, then newgroup is identical to group.

Note
----

Currently, each of the ranks to exclude must be a valid rank in the
group and all elements must be distinct or the function is erroneous.
This restriction is per the draft.

Errors
------

Almost all MPI routines return an error value; C routines as the value
of the function and Fortran routines in the last argument.

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
:ref:`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.


.. seealso:: :ref:`MPI_Group_range_excl`
