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