17.2.431. MPI_Win_create_dynamic

MPI_Win_create_dynamic - One-sided MPI call that returns a window object for RMA operations.

17.2.431.1. SYNTAX

17.2.431.1.1. C Syntax

#include <mpi.h>

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

17.2.431.1.2. Fortran Syntax

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

17.2.431.1.3. 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

17.2.431.2. INPUT PARAMETERS

  • info: Info argument (handle).

  • comm: Communicator (handle).

17.2.431.3. OUTPUT PARAMETERS

  • win: Window object returned by the call (handle).

  • IERROR: Fortran only: Error status (integer).

17.2.431.4. DESCRIPTION

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 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 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.

17.2.431.5. NOTES

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

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

17.2.431.6. ERRORS

Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument.

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.