NAME

       MPI_Comm_split_type  - Creates new communicators based on colors and keys.

SYNTAX

C Syntax

       #include <mpi.h>
       int MPI_Comm_split_type(MPI_Comm comm, int split_type, int key,
            MPI_Info info, MPI_Comm *newcomm)

Fortran Syntax

       INCLUDE 'mpif.h'
       MPI_COMM_SPLIT_TYPE(COMM, SPLIT_TYPE, KEY, INFO, NEWCOMM, IERROR)
            INTEGER   COMM, SPLIT_TYPE, KEY, INFO, NEWCOMM, IERROR

INPUT PARAMETERS

       comm      Communicator (handle).

       split_type
                 Type of processes to be grouped together (integer).

       key       Control of rank assignment (integer).

       info      Info argument (handle).

OUTPUT PARAMETERS

       newcomm   New communicator (handle).

       IERROR    Fortran only: Error status (integer).

DESCRIPTION

       This  function  partitions  the  group  associated  with  comm into disjoint subgroups, based on the type
       specied by split_type. Each subgroup contains all processes of the same type.  Within each subgroup,  the
       processes are ranked in the order defined by the value of the argument key, with ties broken according to
       their  rank  in  the  old group. A new communicator is created for each subgroup and returned in newcomm.
       This is a collective call; all processes must provide the same split_type, but each process is  permitted
       to  provide  different  values  for  key. An exception to this rule is that a process may supply the type
       value MPI_UNDEFINED, in which case newcomm returns MPI_COMM_NULL.

SPLIT TYPES

       MPI_COMM_TYPE_SHARED
                 This type splits the communicator into subcommunicators, each of  which  can  create  a  shared
                 memory region.

ERRORS

       Almost  all  MPI  routines  return  an  error  value; C routines as the value of the function and Fortran
       routines in the last argument.

       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_create
       MPI_Intercomm_create
       MPI_Comm_dup
       MPI_Comm_free
       MPI_Comm_split

1.10.2                                            Jan 21, 2016                            MPI_Comm_split_type(3)