MPI_Get_accumulate(3) MPI MPI_Get_accumulate(3)NAMEMPI_Get_accumulate - Perform an atomic, one-sided read-and-accumulate
operation.
SYNOPSIS
int MPI_Get_accumulate(const void *origin_addr, int origin_count,
MPI_Datatype origin_datatype, void *result_addr, int result_count,
MPI_Datatype result_datatype, int target_rank, MPI_Aint target_disp,
int target_count, MPI_Datatype target_datatype, MPI_Op op, MPI_Win win)
Accumulate origin_count elements of type origin_datatype from the ori‐
gin buffer (origin_addr) to the buffer at offset target_disp, in the
target window specified by target_rank and win, using the operation op
and return in the result buffer result_addr the content of the target
buffer before the accumulation.
INPUT PARAMETERS
origin_addr
- initial address of buffer (choice)
origin_count
- number of entries in buffer (nonnegative integer)
origin_datatype
- datatype of each buffer entry (handle)
result_addr
- initial address of result buffer (choice)
result_count
- number of entries in result buffer (non-negative integer)
result_datatype
- datatype of each entry in result buffer (handle)
target_rank
- rank of target (nonnegative integer)
target_disp
- displacement from start of window to beginning of target buf‐
fer (nonnegative integer)
target_count
- number of entries in target buffer (nonnegative integer)
target_datatype
- datatype of each entry in target buffer (handle)
op - predefined reduce operation (handle)
win - window object (handle)
NOTES
This operations is atomic with respect to other "accumulate" opera‐
tions.
The get and accumulate steps are executed atomically for each basic
element in the datatype (see MPI 3.0 Section 11.7 for details). The
predefined operation MPI_REPLACE provides fetch-and-set behavior.
The origin and result buffers (origin_addr and result_addr) must be
disjoint. Each datatype argument must be a predefined datatype or a
derived datatype where all basic components are of the same predefined
datatype. All datatype arguments must be constructed from the same pre‐
defined datatype. The operation op applies to elements of that prede‐
fined type. target_datatype must not specify overlapping entries, and
the target buffer must fit in the target window or in attached memory
in a dynamic window.
Any of the predefined operations for MPI_Reduce , as well as MPI_NO_OP
or MPI_REPLACE can be specified as op. User-defined functions cannot be
used. A new predefined operation, MPI_NO_OP , is defined. It corre‐
sponds to the associative function f (a, b) = a; i.e., the current
value in the target memory is returned in the result buffer at the ori‐
gin and no operation is performed on the target buffer. MPI_NO_OP can
be used only in MPI_Get_accumulate , MPI_Rget_accumulate , and
MPI_Fetch_and_op . MPI_NO_OP cannot be used in MPI_Accumulate ,
MPI_Raccumulate , or collective reduction operations, such as
MPI_Reduce and others.
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 com‐
municators), 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 prede‐
fined 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_ARG
- Invalid argument. Some argument is invalid and is not identi‐
fied by a specific error class (e.g., MPI_ERR_RANK ).
MPI_ERR_COUNT
- Invalid count argument. Count arguments must be non-negative;
a count of zero is often valid.
MPI_ERR_RANK
- Invalid source or destination rank. Ranks must be between
zero and the size of the communicator minus one; ranks in a
receive ( MPI_Recv , MPI_Irecv , MPI_Sendrecv , etc.) may also
be MPI_ANY_SOURCE .
MPI_ERR_TYPE
- Invalid datatype argument. Additionally, this error can occur
if an uncommitted MPI_Datatype (see MPI_Type_commit ) is used in
a communication call.
MPI_ERR_WIN
- Invalid MPI window object
SEE ALSO
MPI_Rget_accumulate MPI_Fetch_and_op
11/9/2015 MPI_Get_accumulate(3)
