MPI_Put(3OpenMPI) MPI_Put(3OpenMPI)
NAME
MPI_Put - Copies data from the origin memory to the target.
SYNTAX
C Syntax
#include <mpi.h>
MPI_Put(void *origin_addr, int origin_count, MPI_Datatype
origin_datatype, int target_rank, MPI_Aint target_disp,
int target_count, MPI_Datatype target_datatype, MPI_Win win)
Fortran Syntax (see FORTRAN 77 NOTES)
INCLUDE 'mpif.h'
MPI_PUT(ORIGIN_ADDR, ORIGIN_COUNT, ORIGIN_DATATYPE, TARGET_RANK,
TARGET_DISP, TARGET_COUNT, TARGET_DATATYPE, WIN, IERROR)
<type> ORIGIN_ADDR(*)
INTEGER(KIND=MPI_ADDRESS_KIND) TARGET_DISP
INTEGER ORIGIN_COUNT, ORIGIN_DATATYPE, TARGET_RANK, TARGET_COUNT,
TARGET_DATATYPE, WIN, IERROR
C++ Syntax
#include <mpi.h>
void MPI::Win::Put(const void* origin_addr, int origin_count, const
MPI::Datatype& origin_datatype, int target_rank, MPI::Aint
target_disp, int target_count, const MPI::Datatype&
target_datatype) const
INPUT PARAMETERS
origin_addr
Initial address of origin buffer (choice).
origin_count
Number of entries in origin buffer (nonnegative integer).
origin_datatype
Data type of each entry in origin buffer (handle).
target_rank
Rank of target (nonnegative integer).
target_disp
Displacement from start of window to target buffer (nonnegative integer).
target_count
Number of entries in target buffer (nonnegative integer).
target_datatype
Data type of each entry in target buffer (handle).
win Window object used for communication (handle).
OUTPUT PARAMETER
IERROR Fortran only: Error status (integer).
DESCRIPTION
MPI_Put transfers origin_count successive entries of the type specified by origin_datatype, starting at address origin_addr on the origin
node to the target node specified by the win, target_rank pair. The data are written in the target buffer at address target_addr = win-
dow_base + target_disp x disp_unit, where window_base and disp_unit are the base address and window displacement unit specified at window
initialization, by the target process.
The target buffer is specified by the arguments target_count and target_datatype.
The data transfer is the same as that which would occur if the origin process executed a send operation with arguments origin_addr, ori-
gin_count, origin_datatype, target_rank, tag, comm, and the target process executed a receive operation with arguments target_addr, tar-
get_count, target_datatype, source, tag, comm, where target_addr is the target buffer address computed as explained above, and comm is a
communicator for the group of win.
The communication must satisfy the same constraints as for a similar message-passing communication. The target_datatype may not specify
overlapping entries in the target buffer. The message sent must fit, without truncation, in the target buffer. Furthermore, the target buf-
fer must fit in the target window. In addition, only processes within the same buffer can access the target window.
The target_datatype argument is a handle to a datatype object defined at the origin process. However, this object is interpreted at the
target process: The outcome is as if the target datatype object were defined at the target process, by the same sequence of calls used to
define it at the origin process. The target data type must contain only relative displacements, not absolute addresses. The same holds for
get and accumulate.
NOTES
The target_datatype argument is a handle to a datatype object that is defined at the origin process, even though it defines a data layout
in the target process memory. This does not cause problems in a homogeneous or heterogeneous environment, as long as only portable data
types are used (portable data types are defined in Section 2.4 of the MPI-2 Standard).
The performance of a put transfer can be significantly affected, on some systems, from the choice of window location and the shape and
location of the origin and target buffer: Transfers to a target window in memory allocated by MPI_Alloc_mem may be much faster on shared
memory systems; transfers from contiguous buffers will be faster on most, if not all, systems; the alignment of the communication buffers
may also impact performance.
FORTRAN 77 NOTES
The MPI standard prescribes portable Fortran syntax for the TARGET_DISP argument only for Fortran 90. FORTRAN 77 users may use the non-por-
table syntax
INTEGER*MPI_ADDRESS_KIND TARGET_DISP
where MPI_ADDRESS_KIND is a constant defined in mpif.h and gives the length of the declared integer in bytes.
ERRORS
Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument. C++ func-
tions do not return errors. If the default error handler is set to MPI::ERRORS_THROW_EXCEPTIONS, then on error the C++ exception mechanism
will be used to throw an MPI:Exception object.
Before the error value is returned, the current MPI error handler is called. By default, this error handler aborts the MPI job, except for
I/O function errors. The error handler may be changed with MPI_Comm_set_errhandler; 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.
SEE ALSO
MPI_Get
MPI_Accumulate
Open MPI 1.2 September 2006 MPI_Put(3OpenMPI)