NAME

       MPI_Cart_map  -  Maps process to Cartesian topology information.

SYNTAX

C Syntax

       #include <mpi.h>
       int MPI_Cart_map(MPI_Comm comm, int ndims, const int dims[],
            const int periods[], int *newrank)

Fortran Syntax

       USE MPI
       ! or the older form: INCLUDE 'mpif.h'
       MPI_CART_MAP(COMM, NDIMS, DIMS, PERIODS, NEWRANK, IERROR)
            INTEGER   COMM, NDIMS, DIMS(*), NEWRANK, IERROR
            LOGICAL   PERIODS(*)

Fortran 2008 Syntax

       USE mpi_f08
       MPI_Cart_map(comm, ndims, dims, periods, newrank, ierror)
            TYPE(MPI_Comm), INTENT(IN) :: comm
            INTEGER, INTENT(IN) :: ndims, dims(ndims)
            LOGICAL, INTENT(IN) :: periods(ndims)
            INTEGER, INTENT(OUT) :: newrank
            INTEGER, OPTIONAL, INTENT(OUT) :: ierror

C++ Syntax

       #include <mpi.h>
       int Cartcomm::Map(int ndims, const int dims[],
            const bool periods[]) const

INPUT PARAMETERS

       comm      Input communicator (handle).

       ndims     Number of dimensions of Cartesian structure (integer).

       dims      Integer array of size ndims specifying the number of processes in each coordinate direction.

       periods   Logical  array  of  size  ndims  specifying  the  periodicity  specification in each coordinate
                 direction.

OUTPUT PARAMETERS

       newrank   Reordered rank of the calling process; MPI_UNDEFINED if calling process does not belong to grid
                 (integer).

       IERROR    Fortran only: Error status (integer).

DESCRIPTION

       MPI_Cart_map and MPI_Graph_map can be used to implement all other topology  functions.  In  general  they
       will  not  be  called  by  the  user  directly,  unless he or she is creating additional virtual topology
       capability other than that provided by MPI.

       MPI_Cart_map computes an "optimal" placement for the calling process on the physical machine. A  possible
       implementation  of  this  function  is  to always return the rank of the calling process, that is, not to
       perform any reordering.

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_map

4.1.6                                             Sep 30, 2023                                   MPI_Cart_map(3)