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MPI_Alltoallv(3)		      MPI		      MPI_Alltoallv(3)

NAME
       MPI_Alltoallv -	Sends data from	all to all processes; each process may
       send a different	amount of data and provide displacements for the input
       and output data.

SYNOPSIS
       int MPI_Alltoallv(MPICH2_CONST void *sendbuf, MPICH2_CONST int *sendcnts,
			 MPICH2_CONST int *sdispls, MPI_Datatype sendtype, void	*recvbuf,
			 MPICH2_CONST int *recvcnts, MPICH2_CONST int *rdispls,	MPI_Datatype recvtype,
			 MPI_Comm comm)

INPUT PARAMETERS
       sendbuf
	      -	starting address of send buffer	(choice)
       sendcounts
	      -	integer	array equal to the group size specifying the number of
	      elements to send to each processor
       sdispls
	      -	integer	array (of length group size). Entry  j	specifies  the
	      displacement (relative to	sendbuf	 from which to take the	outgo-
	      ing data destined	for process j

       sendtype
	      -	data type of send buffer elements (handle)
       recvcounts
	      -	integer	array equal to the group size specifying  the  maximum
	      number of	elements that can be received from each	processor
       rdispls
	      -	 integer  array	 (of length group size). Entry i specifies the
	      displacement (relative to	recvbuf	 at which to place the	incom-
	      ing data from process i

       recvtype
	      -	data type of receive buffer elements (handle)
       comm   -	communicator (handle)

OUTPUT PARAMETER
       recvbuf
	      -	address	of receive buffer (choice)

THREAD AND INTERRUPT SAFETY
       This  routine  is  thread-safe.	 This  means  that this	routine	may be
       safely used by multiple threads without the need	for any	 user-provided
       thread  locks.  However,	the routine is not interrupt safe.  Typically,
       this is due to the use of memory	allocation routines such as malloc  or
       other  non-MPICH	 runtime  routines  that are themselves	not interrupt-
       safe.

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_ERR_COMM
	      -	Invalid	communicator.  A common	error is to use	a null	commu-
	      nicator in a call	(not even allowed in MPI_Comm_rank ).
       MPI_ERR_COUNT
	      -	Invalid	count argument.	 Count arguments must be non-negative;
	      a	count of zero is often valid.
       MPI_ERR_TYPE
	      -	Invalid	datatype argument.  May	be an uncommitted MPI_Datatype
	      (see MPI_Type_commit ).
       MPI_ERR_BUFFER
	      -	 Invalid  buffer  pointer.  Usually a null buffer where	one is
	      not valid.

LOCATION
       src/mpi/coll/alltoallv.c

				   9/20/2012		      MPI_Alltoallv(3)

NAME | SYNOPSIS | INPUT PARAMETERS | OUTPUT PARAMETER | THREAD AND INTERRUPT SAFETY | NOTES FOR FORTRAN | ERRORS | LOCATION

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