MPI_Win_create(3) MPI MPI_Win_create(3)

MPI_Win_create - Create an MPI Window object for one-sided communication



int MPI_Win_create(void *base, MPI_Aint size, int disp_unit, MPI_Info info,
MPI_Comm comm, MPI_Win *win)




int MPI_Win_create_c(void *base, MPI_Aint size, MPI_Aint disp_unit,
MPI_Info info, MPI_Comm comm, MPI_Win *win)













  

  
- initial address of window (choice)

  

  
- size of window in bytes (non-negative integer)

  

  
- local unit size for displacements, in bytes (positive integer)

  

  
- info argument (handle)

  

  
- intra-communicator (handle)
    

  











  

  
- window object (handle)
    

  










The displacement unit argument is provided to facilitate address
    arithmetic in RMA operations: the target displacement argument of an RMA
    operation is scaled by the factor disp_unit specified by the target process,
    at window creation.


The info argument provides optimization hints to the runtime about
    the expected usage pattern of the window. The following info keys are
    predefined.





  

  
- If set to true, then the implementation may assume that passive target
      synchronization (i.e., MPI_Win_lock , MPI_Win_lock_all )
      will not be used on the given window. This implies that this window is not
      used for 3-party communication, and RMA can be implemented with no (less)
      asynchronous agent activity at this process.
    

  

  

  
- Controls the ordering of accumulate operations at the target. The
      argument string should contain a comma-separated list of the following
      read/write ordering rules, where e.g. "raw" means
      read-after-write: "rar,raw,war,waw".
    

  

  

  
- If set to same_op, the implementation will assume that all concurrent
      accumulate calls to the same target address will use the same operation.
      If set to same_op_no_op, then the implementation will assume that all
      concurrent accumulate calls to the same target address will use the same
      operation or MPI_NO_OP . This can eliminate the need to protect
      access for certain operation types where the hardware can guarantee
      atomicity. The default is same_op_no_op.
    

  

  

  
- Controls the desired synchronization granularity for accumulate ops. It
      sets the size of memory range in bytes for which the MPI library should
      acquire a synchronization primitive to ensure the atomicity of updates.
      The default is 0 which let the MPI library decides the granularity. When
      the info hint is set to a positive value, the actual range of
      synchroniation is round-up to the next size that fits the Datatype used in
      the accumulate operation (see MPI standard 4.1). All processes in the
      group of a windows must set to the same value.
    

  










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.










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.










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
    communicators), MPI_File_set_errhandler (for files), and
    MPI_Win_set_errhandler (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 guarantee that an MPI
    program can continue past an error; however, MPI implementations will
    attempt to continue whenever possible.





  

  
- No error; MPI routine completed successfully.

  

  
- Invalid argument. Some argument is invalid and is not identified by a
      specific error class (e.g., MPI_ERR_RANK ).

  

  
- Invalid communicator. A common error is to use a null communicator in a
      call (not even allowed in MPI_Comm_rank ).

  

  
-

  

  
- Invalid Info

  

  
-

  

  
- Other error; use MPI_Error_string to get more information about
      this error code.
    

  










MPI_Win_allocate MPI_Win_allocate_shared MPI_Win_create_dynamic
    MPI_Win_free







  

    2/9/2024