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MPI_Get_accumulate(3)		      MPI		 MPI_Get_accumulate(3)

NAME
       MPI_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 el-
       ement  in the datatype (see MPI 3.0 Section 11.7	for details). The pre-
       defined 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_Re-
       duce 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_er-
       rhandler	 (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 guarentee	that an	MPI program can	continue  past
       an  error;  however, MPI	implementations	will attempt to	continue when-
       ever 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 re-
	      ceive ( 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

				  11/10/2017		 MPI_Get_accumulate(3)

NAME | SYNOPSIS | INPUT PARAMETERS | NOTES | NOTES FOR FORTRAN | ERRORS | SEE ALSO

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