Creates a new communicator


#include "mpi.h"
int MPI_Comm_create ( comm, group, comm_out )
MPI_Comm  comm;
MPI_Group group;
MPI_Comm *comm_out;

Input Parameters

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

Output Parameter

new communicator (handle)

Notes for Fortran

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

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


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 lastargument. Before the value is returned, the current MPI error handler iscalled. By default, this error handler aborts the MPI job. The error handlermay be changed with MPI_Errhandler_set; the predefined error handlerMPI_ERRORS_RETURN may be used to cause error values to be returned. Note that MPI does not guarentee that an MPI program can continue pastan error.

No error; MPI routine completed successfully.
Invalid communicator. A common error is to use a null communicator in a call (not even allowed in MPI_Comm_rank).
Null group passed to function.
This error is returned when some part of the MPICH implementation is unable to acquire memory.

See Also