MPI_Comm_create(3)

NAME
MPI_Comm_create - Creates a intracommunicator from the given group

SYNOPSIS
#include <mpi.h>
int MPI_Comm_create(MPI_Comm comm, MPI_Group group, MPI_Comm *out);

#include <pmpi.h>
int PMPI_Comm_create(MPI_Comm comm, MPI_Group group, MPI_Comm *out);

#include <mpi.h>
MPI::Intracomm MPI::Intracomm::Create(const Group &group) const;

INCLUDE 'mpif.h'
MPI_COMM_CREATE(comm, group, out, ierr)
INTEGER comm, group, out, ierr

INPUT PARAMETERS
comm
    - intracommunicator (handle)
group
    - group (handle)

OUTPUT PARAMETER
out - the new intracommunicator (handle).

DESCRIPTION
The MPI_Comm_create() function is used to create a new intracommunicator from a group using an already existing intracommunicator comm for internal comunication. In C++, this function returns the new intracommunicator out, as its return value. The original communicator must be a valid one (not MPI_COMM_NULL). PMPI_Comm_create() is the profiling version of this function. If the process is not a member of group then MPI_COMM_NULL is returned in out

ERRORS
All MPI routines except for MPI_Wtime and MPI_Wtick return an error code. The the current MPI error handler is invoked if the return value is not MPI_SUCCESS. The default error handler aborts, but this may be changed with by using the MPI_Errhandler_set() function. The predefined error handler MPI_ERRORS_RETURN may be used to cause error values to be returned instead. Note that MPI does not guarentee that an MPI program can continue past an error. In this implementation, all errors except MPI_ERR_INTERN or MPI_ERR_OTHER should always be recoverable. In C, the error code is passed as the return value. In FORTRAN, all functions have an parameter ierr which returns the error code. MPI C++ functions do not directly return an error code. However, C++ users may want to use the MPI::ERRORS_THROW_EXCEPTIONS handler. This will throw an MPI::Exception with the corresponding error code. To prevent exceptions from being raised from within C and Fortran code, they will see all error return values as MPI_ERR_PENDING when this handler is chosen. In this implementation, call MPI::throw_exception() to throw the correct exception if this occurs.
MPI_SUCCESS
    - No error;
MPI_ERR_PENDING
    - Pending exception;
MPI_ERR_COMM
    - Invalid communicator;
MPI_ERR_ARG
    - Invalid output pointer;
MPI_ERR_INTERN
    - Out of memory error. This may be fatal.

SEE ALSO
MPI_Comm_size(3), MPI_Comm_remote_size(3), MPI_Comm_rank(3), MPI_Comm_dup(3), MPI_Comm_split(3), MPI_Comm_free(3), MPI_Intercomm_create(3), MPI_Intercomm_merge(3)