.TH MPI_Rget_accumulate 3 "11/12/2019" " " "MPI"

.SH NAME

MPI_Rget_accumulate \-  Perform an atomic, one-sided read-and-accumulate operation and return a request handle for the operation. 

.SH SYNOPSIS

.nf

int MPI_Rget_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,

MPI_Request * request)

.fi

.I MPI_Rget_accumulate

is similar to 

.I MPI_Get_accumulate

, except that it allocates

a communication request object and associates it with the request handle (the

argument request) that can be used to wait or test for completion. The

completion of an 

.I MPI_Rget_accumulate

operation indicates that the data is

available in the result buffer and the origin buffer is free to be updated. It

does not indicate that the operation has been completed at the target window.

.SH INPUT PARAMETERS

.PD 0

.TP

.B origin_addr 

- initial address of buffer (choice)

.PD 1

.PD 0

.TP

.B origin_count 

- number of entries in buffer (nonnegative integer)

.PD 1

.PD 0

.TP

.B origin_datatype 

- datatype of each buffer entry (handle)

.PD 1

.PD 0

.TP

.B result_addr 

- initial address of result buffer (choice)

.PD 1

.PD 0

.TP

.B result_count 

- number of entries in result buffer (non-negative integer)

.PD 1

.PD 0

.TP

.B result_datatype 

- datatype of each entry in result buffer (handle)

.PD 1

.PD 0

.TP

.B target_rank 

- rank of target (nonnegative integer)

.PD 1

.PD 0

.TP

.B target_disp 

- displacement from start of window to beginning of target

buffer (nonnegative integer)

.PD 1

.PD 0

.TP

.B target_count 

- number of entries in target buffer (nonnegative integer)

.PD 1

.PD 0

.TP

.B target_datatype 

- datatype of each entry in target buffer (handle)

.PD 1

.PD 0

.TP

.B op 

- predefined reduce operation (handle)

.PD 1

.PD 0

.TP

.B win 

- window object (handle)

.PD 1

.SH OUTPUT PARAMETERS

.PD 0

.TP

.B request 

- RMA request (handle)

.PD 1

.SH NOTES

This operations is atomic with respect to other "accumulate" operations.

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

.I MPI_REPLACE

provides fetch-and-set behavior.

The basic components of both the origin and target datatype must be the same

predefined datatype (e.g., all 

.I MPI_INT

or all 

.I MPI_DOUBLE_PRECISION

).

.SH NOTES FOR FORTRAN

All MPI routines in Fortran (except for 

.I MPI_WTIME

and 

.I MPI_WTICK

) have

an additional argument 

.I ierr

at the end of the argument list.  

.I 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

.I call

statement.

All MPI objects (e.g., 

.I MPI_Datatype

, 

.I MPI_Comm

) are of type 

.I INTEGER

in Fortran.

.SH ERRORS

All MPI routines (except 

.I MPI_Wtime

and 

.I 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 

.I MPI_Comm_set_errhandler

(for communicators),

.I MPI_File_set_errhandler

(for files), and 

.I MPI_Win_set_errhandler

(for

RMA windows).  The MPI-1 routine 

.I MPI_Errhandler_set

may be used but

its use is deprecated.  The predefined error handler

.I MPI_ERRORS_RETURN

may be used to cause error values to be returned.

Note that MPI does 

.B not

guarentee that an MPI program can continue past

an error; however, MPI implementations will attempt to continue whenever

possible.

.PD 0

.TP

.B MPI_SUCCESS 

- No error; MPI routine completed successfully.

.PD 1

.PD 0

.TP

.B MPI_ERR_ARG 

- Invalid argument.  Some argument is invalid and is not

identified by a specific error class (e.g., 

.I MPI_ERR_RANK

).

.PD 1

.PD 0

.TP

.B MPI_ERR_COUNT 

- Invalid count argument.  Count arguments must be 

non-negative; a count of zero is often valid.

.PD 1

.PD 0

.TP

.B 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

(

.I MPI_Recv

, 

.I MPI_Irecv

, 

.I MPI_Sendrecv

, etc.) may also be 

.I MPI_ANY_SOURCE

\&.

.PD 1

.PD 0

.TP

.B MPI_ERR_TYPE 

- Invalid datatype argument.  Additionally, this error can

occur if an uncommitted MPI_Datatype (see 

.I MPI_Type_commit

) is used

in a communication call.

.PD 1

.PD 0

.TP

.B MPI_ERR_WIN 

- Invalid MPI window object

.PD 1

.SH SEE ALSO

MPI_Get_accumulate MPI_Fetch_and_op

.br