mpi_comm_create(3openmpi) [osx man page]

MPI_Comm_create(3OpenMPI)												 MPI_Comm_create(3OpenMPI)

NAME

       MPI_Comm_create - Creates a new communicator.

SYNTAX

C Syntax
       #include <mpi.h>
       int MPI_Comm_create(MPI_Comm comm, MPI_Group group, MPI_Comm *newcomm)

Fortran Syntax
       INCLUDE 'mpif.h'
       MPI_COMM_CREATE(COMM, GROUP, NEWCOMM, IERROR)
	    INTEGER   COMM, GROUP, NEW, IERROR

C++ Syntax
       #include <mpi.h>
       MPI::Intercomm MPI::Intercomm::Create(const Group& group) const

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

INPUT PARAMETER

       comm	 Communicator (handle).

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

OUTPUT PARAMETERS

       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 MPI_COMM_NULL 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.

NOTES

       MPI_Comm_create 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 MPI_Comm_create, can be used in subsequent calls to MPI_Comm_create (or other communicator construc-
       tors) to further subdivide a computation into parallel sub-computations. A more general service is provided by MPI_Comm_split.

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++ func-
       tions  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_Comm_split

       MPI_Intercomm_create

Open MPI 1.2							  September 2006					 MPI_Comm_create(3OpenMPI)

Check Out this Related Man Page

MPI_Comm_create(3)							MPI							MPI_Comm_create(3)

NAME

       MPI_Comm_create -  Creates a new communicator

SYNOPSIS

       int MPI_Comm_create(MPI_Comm comm, MPI_Group group, MPI_Comm *newcomm)

INPUT PARAMETERS

       comm   - communicator (handle)
       group  - group, which is a subset of the group of comm (handle)

OUTPUT PARAMETER

       comm_out
	      - new communicator (handle)

THREAD AND INTERRUPT SAFETY

       This  routine  is  thread-safe.	This means that this routine may be safely used by multiple threads without the need for any user-provided
       thread locks.  However, the routine is not interrupt safe.  Typically, this is due to the use of memory allocation routines such as  malloc
       or other non-MPICH runtime routines that are themselves not interrupt-safe.

NOTES FOR FORTRAN

       All  MPI  routines in Fortran (except for MPI_WTIME and MPI_WTICK ) have an additional argument ierr at the end of the argument list.  ierr
       is an integer and has the same meaning as the return value of the routine in C.	In Fortran, MPI routines are subroutines, and are  invoked
       with the call statement.

       All MPI objects (e.g., MPI_Datatype , MPI_Comm ) are of type INTEGER in Fortran.

ERRORS

       All  MPI  routines (except MPI_Wtime and MPI_Wtick ) return an error value; C routines as the value of the function and Fortran routines in
       the last argument.  Before the value is returned, the current MPI error handler is called.  By default, this error handler aborts  the  MPI
       job.   The  error  handler  may	be  changed  with  MPI_Comm_set_errhandler  (for  communicators), MPI_File_set_errhandler (for files), and
       MPI_Win_set_errhandler (for RMA windows).  The MPI-1 routine MPI_Errhandler_set may be used but its  use  is  deprecated.   The	predefined
       error handler MPI_ERRORS_RETURN may be used to cause error values to be returned.  Note that MPI does not guarentee that an MPI program can
       continue past an error; however, MPI implementations will attempt to continue whenever possible.

       MPI_SUCCESS
	      - No error; MPI routine completed successfully.
       MPI_ERR_COMM
	      - Invalid communicator.  A common error is to use a null communicator in a call (not even allowed in MPI_Comm_rank ).
       MPI_ERR_GROUP
	      - Null or invalid group passed to function.

SEE ALSO

       MPI_Comm_free

LOCATION

       comm_create.c

								     4/7/2011							MPI_Comm_create(3)

Linux and UNIX Man Pages

mpi_comm_create(3openmpi) [osx man page]

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