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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)

       Accumulate  one	element	 of type datatype from the origin buffer (ori-
       gin_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)
       result_addr
	      -	initial	address	of result buffer (choice)
       datatype
	      -	 datatype  of  the entry in origin, result, and	target buffers
	      (handle)
       target_rank
	      -	rank of	target (nonnegative integer)
       target_disp
	      -	displacement from start	of window to beginning of target  buf-
	      fer (non-negative	integer)
       op     -	reduce operation (handle)
       win    -	window object (handle)

NOTES
       This  operations	 is  atomic  with respect to other "accumulate"	opera-
       tions.

       The generic functionality of MPI_Get_accumulate might limit the perfor-
       mance  of fetch-and-increment or	fetch-and-add calls that might be sup-
       ported by special hardware operations.	MPI_Fetch_and_op  thus	allows
       for  a fast implementation of a commonly	used subset of the functional-
       ity 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	 func-
       tions  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 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_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 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_Get_accumulate

				  11/10/2017		   MPI_Fetch_and_op(3)

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

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