MPICartsub(3OpenMPI) MPICartsub(3OpenMPI)

NAME
       MMPPIICCaarrttssuubb   -  Partitions  a communicator into subgroups, which form
       lower-dimensional Cartesian subgrids.


SSYYNNTTAAXX
CC SSyynnttaaxx
       #include 
       int MPICartsub(MPIComm comm, int *remaindims, MPIComm *commnew)


FFoorrttrraann SSyynnttaaxx
       INCLUDE 'mpif.h'
       MPICARTSUB(COMM, REMAINDIMS, COMMNEW, IERROR)
            INTEGER   COMM, COMMNEW, IERROR
            LOGICAL   REMAINDIMS(*)


CC++++ SSyynnttaaxx
       #include 
       Cartcomm Cartcomm::Sub(const bool remaindims[]) const


IINNPPUUTT PPAARRAAMMEETTEERRSS
       comm      Communicator with Cartesian structure (handle).

       remaindims
                 The ith entry of remaindims specifies whether the ith dimen-
                 sion  is  kept  in  the  subgrid (true) or is dropped (false)
                 (logical vector).


OOUUTTPPUUTT PPAARRAAMMEETTEERRSS
       commnew  Communicator containing the subgrid that includes the calling
                 process (handle).

       IERROR    Fortran only: Error status (integer).


DESCRIPTION
       If  a  Cartesian  topology  has  been created with MPICartcreate, the
       function  MPICartsub can be used to partition the communicator  group
       into  subgroups  that form lower-dimensional Cartesian subgrids, and to
       build for each subgroup a  communicator  with  the  associated  subgrid
       Cartesian    topology.   (This   function   is   closely   related   to
       MPICommsplit.)

       EExxaammppllee:: Assume that  MPICartcreate( ..., comm) has defined a (2 x  3
       x 4)   grid. Let  remaindims = (true, false, true). Then a call to

           MPICartsub(comm, remaindims, commnew)

       will  create  three communicators, each with eight processes in a 2 x 4
       Cartesian topology. If remaindims = (false, false, true) then the call
       to  MPICartsub(comm,  remaindims, commnew) will create six nonover-
       lapping communicators, each with four processes, in  a  one-dimensional
       Cartesian topology.


EERRRROORRSS
       Almost  all MPI routines return an error value; C routines as the value
       of the function and Fortran routines in the last  argument.  C++  func-
       tions  do  not  return  errors.  If the default error handler is set to
       MPI::ERRORSTHROWEXCEPTIONS, 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
       MPICommseterrhandler; the predefined error handler MPIERRORSRETURN
       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
       MPICartcreate
       MPICommsplit




Open MPI 1.2                    September 2006          MPICartsub(3OpenMPI)