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MPI_Comm_split_type - Creates new communicators based on colors
and keys.
#include <mpi.h>
int MPI_Comm_split_type(MPI_Comm comm, int split_type, int key,
MPI_Info info, MPI_Comm *newcomm)
INCLUDE ’mpif.h’
MPI_COMM_SPLIT_TYPE(COMM, SPLIT_TYPE, KEY, INFO, NEWCOMM, IERROR)
INTEGER COMM, SPLIT_TYPE, KEY, INFO, NEWCOMM, IERROR
- comm
- Communicator (handle).
- split_type
- Type of processes
to be grouped together (integer).
- key
- Control of rank assignment (integer).
- info
- Info argument (handle).
- newcomm
- New communicator
(handle).
- IERROR
- Fortran only: Error status (integer).
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.
- MPI_COMM_TYPE_SHARED
- This type splits the communicator into
subcommunicators, each of which can create a shared memory region.
- OMPI_COMM_TYPE_NODE
- Synonym for MPI_COMM_TYPE_SHARED.
- OMPI_COMM_TYPE_HWTHREAD
- This type splits
the communicator into subcommunicators, each of which belongs to the same
hardware thread.
- OMPI_COMM_TYPE_CORE
- This type splits the communicator into
subcommunicators, each of which belongs to the same core/processing unit.
- OMPI_COMM_TYPE_L1CACHE
- This type splits the communicator into subcommunicators,
each of which belongs to the same L1 cache.
- OMPI_COMM_TYPE_L2CACHE
- This
type splits the communicator into subcommunicators, each of which belongs
to the same L2 cache.
- OMPI_COMM_TYPE_L3CACHE
- This type splits the communicator
into subcommunicators, each of which belongs to the same L3 cache.
- OMPI_COMM_TYPE_SOCKET
- This type splits the communicator into subcommunicators, each of which
belongs to the same socket.
- OMPI_COMM_TYPE_NUMA
- This type splits the communicator
into subcommunicators, each of which belongs to the same NUMA-node.
- OMPI_COMM_TYPE_BOARD
- This type splits the communicator into subcommunicators, each of which
belongs to the same board.
- OMPI_COMM_TYPE_HOST
- This type splits the communicator
into subcommunicators, each of which belongs to the same host.
- OMPI_COMM_TYPE_CU
- This type splits the communicator into subcommunicators, each of which
belongs to the same computational unit.
- OMPI_COMM_TYPE_CLUSTER
- This type
splits the communicator into subcommunicators, each of which belongs to
the same cluster.
The communicator keys denoted with an OMPI_ prefix
instead of an MPI_ prefix are specific to Open MPI, and are not part of
the MPI standard. Their use should be protected by the OPEN_MPI C preprocessor
macro.
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.
MPI_Comm_create
MPI_Intercomm_create
MPI_Comm_dup
MPI_Comm_free
MPI_Comm_split
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