The execution of a put operation is similar to the execution of a send by the origin process and a matching receive by the target process. The obvious difference is that all arguments are provided by one call -- the call executed by the origin process.
MPI_PUT(origin_addr, origin_count, origin_datatype, target_rank, target_disp, target_count, target_datatype, win)
int 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)
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
int 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
void
Transfers origin_count
successive entries of the type specified by the
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 = window_base +
target_dispdisp_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, origin_count, origin_datatype, target_rank, tag, comm, and the target process executed a receive operation with arguments target_addr, target_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 buffer must fit in 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 was defined at the target process, by the same sequence of calls used to define it at the origin process. The target datatype must contain only relative displacements, not absolute addresses. The same holds for get and accumulate.
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.(End of advice to users.)
MPI-Standard for MARMOT