.. _mpi_topo_test:


MPI_Topo_test
=============

.. include_body

:ref:`MPI_Topo_test` |mdash| Determines the type of topology (if any) associated
with a communicator.


SYNTAX
------


C Syntax
^^^^^^^^

.. code-block:: c

   #include <mpi.h>

   int MPI_Topo_test(MPI_Comm comm, int *top_type)


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

.. code-block:: fortran

   USE MPI
   ! or the older form: INCLUDE 'mpif.h'
   MPI_TOPO_TEST(COMM, TOP_TYPE, IERROR)
   	INTEGER	COMM, TOP_TYPE, IERROR


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

.. code-block:: fortran

   USE mpi_f08
   MPI_Topo_test(comm, status, ierror)
   	TYPE(MPI_Comm), INTENT(IN) :: comm
   	INTEGER, INTENT(OUT) :: status
   	INTEGER, OPTIONAL, INTENT(OUT) :: ierror
   		DOUBLE PRECISION MPI_Wtick()
   		DOUBLE PRECISION MPI_Wtime()


INPUT PARAMETER
---------------
* ``comm``: Communicator (handle).

OUTPUT PARAMETERS
-----------------
* ``top_type``: Topology type of communicator comm (choice).
* ``ierror``: Fortran only: Error status (integer).

DESCRIPTION
-----------

The function :ref:`MPI_Topo_test` returns the type of topology that is assigned
to a communicator.

The output value *top_type* is one of the following:

::

       MPI_GRAPH        graph topology
       MPI_CART	        Cartesian topology
       MPI_DIST_GRAPH   distributed graph topology
       MPI_UNDEFINED    no topology


ERRORS
------

.. include:: ./ERRORS.rst

.. seealso::
   * :ref:`MPI_Graph_create`
   * :ref:`MPI_Cart_create`