NAME

       MPI_Topo_test - Determines the type of topology (if any) associated with a communicator.

SYNTAX

C Syntax

       #include <mpi.h>
       int MPI_Topo_test(MPI_Comm comm, int *top_type)

Fortran Syntax

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

Fortran 2008 Syntax

       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()

C++ Syntax

       #include <mpi.h>
       int Comm::Get_topology() const

INPUT PARAMETER

       comm      Communicator (handle).

OUTPUT PARAMETERS

       top_type  Topology type of communicator comm (choice).

       IERROR    Fortran only: Error status (integer).

DESCRIPTION

       The function 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

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

4.1.6                                             Sep 30, 2023                                  MPI_Topo_test(3)