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MPI_Win_create_dynamic.3.rst

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MPI_Win_create_dynamic

:ref:`MPI_Win_create_dynamic` |mdash| One-sided MPI call that returns a window object for RMA operations.

SYNTAX

C Syntax

#include <mpi.h>

MPI_Win_create_dynamic(MPI_Info info, MPI_Comm comm, MPI_Win *win)

Fortran Syntax

USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_WIN_CREATE_DYNAMIC(INFO, COMM, WIN, IERROR)
     INTEGER INFO, COMM, WIN, IERROR

Fortran 2008 Syntax

USE mpi_f08
MPI_Win_create_dynamic(info, comm, win, ierror)
     TYPE(MPI_Info), INTENT(IN) :: info
     TYPE(MPI_Comm), INTENT(IN) :: comm
     TYPE(MPI_Win), INTENT(OUT) :: win
     INTEGER, OPTIONAL, INTENT(OUT) :: ierror

INPUT PARAMETERS

  • info: Info argument (handle).
  • comm: Communicator (handle).

OUTPUT PARAMETERS

  • win: Window object returned by the call (handle).
  • ierror: Fortran only: Error status (integer).

DESCRIPTION

:ref:`MPI_Win_create_dynamic` is a one-sided MPI communication collective call executed by all processes in the group of comm. It returns a window object without memory attached that can be used by these processes to perform RMA operations.

A window created with :ref:`MPI_Win_create_dynamic` requires the target_disp argument for all RMA communication functions to be the actual address at the target.

The following info keys are supported:

no_locks
If set to true, then the implementation may assume that the local window is never locked (by a call to :ref:`MPI_Win_lock` or MPI_Win_lock_all). Setting this value if only active synchronization may allow the implementation to enable certain optimizations.
accumulate_ordering
By default, accumulate operations from one initiator to one target on the same window memory location are strictly ordered. If the info key accumulate_ordering is set to none, no ordering of accumulate operations guaranteed. They key can also be a comma-separated list of required orderings consisting of rar, war, raw, and waw for read-after-read, write-after-read, read-after-write, and write-after-write, respectively. Looser ordering constraints are likely to result in improved performance.
accumulate_ops
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. The default is same_op_no_op.

NOTES

Since dynamically attaching memory to a window is a local operation, one has to communicate the actual address at the target using :ref:`MPI_Get_address` and some communication.

Dynamic memory does not have any disp_unit associated and requires correct offset calculations with proper type handling.

ERRORS

.. seealso::
   * :ref:`MPI_Win_attach`
   * :ref:`MPI_Win_detach`
   * :ref:`MPI_Get_address`