MPICommcreate(3OpenMPI) MPICommcreate(3OpenMPI)

NAME
       MMPPIICCoommmmccrreeaattee - Creates a new communicator.


SSYYNNTTAAXX
CC SSyynnttaaxx
       #include 
       int MPICommcreate(MPIComm comm, MPIGroup group, MPIComm *newcomm)


FFoorrttrraann SSyynnttaaxx
       INCLUDE 'mpif.h'
       MPICOMMCREATE(COMM, GROUP, NEWCOMM, IERROR)
            INTEGER   COMM, GROUP, NEW, IERROR


CC++++ SSyynnttaaxx
       #include 
       MPI::Intercomm MPI::Intercomm::Create(const Group& group) const

       MPI::Intracomm MPI::Intracomm::Create(const Group& group) const


IINNPPUUTT PPAARRAAMMEETTEERR
       comm      Communicator (handle).

       group     Group, which is a subset of the group of comm (handle).


OOUUTTPPUUTT PPAARRAAMMEETTEERRSS
       newcomm   New communicator (handle).

       IERROR    Fortran only: Error status (integer).


DESCRIPTION
       This  function  creates  a  new communicator newcomm with communication
       group defined by group and a new context. The function sets newcomm  to
       a  new communicator that spans all the processes that are in the group.
       It sets newcomm to MPICOMMNULL for processes  that  are  not  in  the
       group.   The call is erroneous if not all group arguments have the same
       value, or if group is not a subset of the group associated  with  comm.
       Note  that  the call must be executed by all processes in comm, even if
       they do not belong to the new group.




NNOOTTEESS
       MPICommcreate provides a means of making a subset  of  processes  for
       the  purpose  of separate MIMD computation, with separate communication
       space. newcomm, which is created by MPICommcreate,  can  be  used  in
       subsequent  calls  to  MPICommcreate (or other communicator construc-
       tors) to further subdivide a  computation  into  parallel  sub-computa-
       tions. A more general service is provided by MPICommsplit.


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
       MPICommsplit

       MPIIntercommcreate




Open MPI 1.2                    September 2006       MPICommcreate(3OpenMPI)