MPI_Fetch_and_op(3) MPI MPI_Fetch_and_op(3)
NAME
MPI_Fetch_and_op - Perform one-sided read-modify-write.
SYNOPSIS
int MPI_Fetch_and_op(const void *origin_addr, void *result_addr,
MPI_Datatype datatype, int target_rank,
MPI_Aint target_disp, MPI_Op op, MPI_Win win)
INPUT PARAMETERS
origin_addr
- initial address of buffer (choice)
datatype
- datatype of the entry in origin, result, and target buffers
(handle)
target_rank
- rank of target (non-negative integer)
target_disp
- displacement from start of window to beginning of target buffer
(non-negative integer)
op - reduce operation (handle)
win - window object (handle)
OUTPUT PARAMETERS
result_addr
- initial address of result buffer (choice)
NOTES
This operations is atomic with respect to other "accumulate" operations.
The generic functionality of MPI_Get_accumulate might limit the
performance of fetch-and-increment or fetch-and-add calls that might be
supported by special hardware operations. MPI_Fetch_and_op thus allows
for a fast implementation of a commonly used subset of the functionality
of MPI_Get_accumulate .
The origin and result buffers (origin_addr and result_addr) must be
disjoint. 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. The datatype argument must be a predefined datatype.
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 communicators),
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 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; however, MPI
implementations will attempt to continue whenever possible.
MPI_SUCCESS
- No error; MPI routine completed successfully.
MPI_ERR_DISP
-
MPI_ERR_OP
- Invalid operation. MPI operations (objects of type MPI_Op )
must either be one of the predefined operations (e.g., MPI_SUM )
or created with MPI_Op_create .
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
MPI_ERR_OTHER
- Other error; use MPI_Error_string to get more information about
this error code.
SEE ALSO
MPI_Get_accumulate
1/27/2023 MPI_Fetch_and_op(3)
mpi 4.1 - Generated Sat Jan 28 07:52:38 CST 2023