mpi_alloc_mem(3openmpi) [osx man page]

MPI_Alloc_mem(3OpenMPI) 												   MPI_Alloc_mem(3OpenMPI)

NAME

       MPI_Alloc_mem  - Allocates a specified memory segment.

SYNTAX

C Syntax
       #include <mpi.h>
       int MPI_Alloc_mem(MPI_Aint size, MPI_Info info, void *baseptr)

Fortran Syntax (see FORTRAN NOTES)
       INCLUDE 'mpif.h'
       MPI_ALLOC_MEM(SIZE, INFO, BASEPTR, IERROR)
	    INTEGER INFO, IERROR
	    INTEGER(KIND=MPI_ADDRESS_KIND) SIZE, BASEPTR

C++ Syntax
       #include <mpi.h>
       void* MPI::Alloc_mem(MPI::Aint size, const MPI::Info& info)

INPUT PARAMETERS

       size	 Size of memory segment in bytes (nonnegative integer).

       info	 Info argument (handle).

OUTPUT PARAMETERS

       baseptr	 Pointer to beginning of memory segment allocated.

       IERROR	 Fortran only: Error status (integer).

DESCRIPTION

       MPI_Alloc_mem allocates size bytes of memory. The starting address of this memory is returned in the variable base.

FORTRAN NOTES

       There  is  no  portable	FORTRAN  77  syntax for using MPI_Alloc_mem.  There is no portable Fortran syntax for using pointers returned from
       MPI_Alloc_mem. However, MPI_Alloc_mem can be used with Sun Fortran compilers.

       From FORTRAN 77, you can use the following non-standard declarations for the SIZE and BASEPTR arguments:
		  INCLUDE "mpif.h"
		  INTEGER*MPI_ADDRESS_KIND SIZE, BASEPTR

       From either FORTRAN 77 or Fortran 90, you can use "Cray pointers" for the BASEPTR argument. Cray pointers are described further in the For-
       tran User's Guide and are supported by many Fortran compilers.  For example,

		  INCLUDE "mpif.h"
		  REAL*4 A(100,100)
		  POINTER (BASEPTR, A)
		  INTEGER*MPI_ADDRESS_KIND SIZE

		  SIZE = 4 * 100 * 100
		  CALL MPI_ALLOC_MEM(SIZE,MPI_INFO_NULL,BASEPTR,IERR)

		  ! use A

		  CALL MPI_FREE_MEM(A, IERR)

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_Free_mem

Open MPI 1.2							  September 2006					   MPI_Alloc_mem(3OpenMPI)

MPI_Win_create(3OpenMPI)												  MPI_Win_create(3OpenMPI)

NAME

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

SYNTAX

C Syntax
       #include <mpi.h>
       MPI_Win_create(void *base, MPI_Aint size, int disp_unit,
	    MPI_Info info, MPI_Comm comm, MPI_Win *win)

Fortran Syntax (see FORTRAN 77 NOTES)
       INCLUDE 'mpif.h'
       MPI_WIN_CREATE(BASE, SIZE, DISP_UNIT, INFO, COMM, WIN, IERROR)
	    <type> BASE(*)
	    INTEGER(KIND=MPI_ADDRESS_KIND) SIZE
	    INTEGER DISP_UNIT, INFO, COMM, WIN, IERROR

C++ Syntax
       #include <mpi.h>
       static MPI::Win MPI::Win::Create(const void* base,
	    MPI::Aint size, int disp_unit, const
	    MPI::Info& info, const MPI::Intracomm& comm)

INPUT PARAMETERS

       base	 Initial address of window (choice).

       size	 Size of window in bytes (nonnegative integer).

       disp_unit Local unit size for displacements, in bytes (positive integer).

       info	 Info argument (handle).

       comm	 Communicator (handle).

OUTPUT PARAMETERS

       win	 Window object returned by the call (handle).

       IERROR	 Fortran only: Error status (integer).

DESCRIPTION

       MPI_Win_create  is a one-sided MPI communication collective call executed by all processes in the group of comm. It returns a window object
       that can be used by these processes to perform RMA operations. Each process specifies a window of existing memory that it  exposes  to  RMA
       accesses  by the processes in the group of comm. The window consists of size bytes, starting at address base. A process may elect to expose
       no memory by specifying size = 0.

       If the base value used by MPI_Win_create was allocated by MPI_Alloc_mem, the size of the window can be no larger than the value set by  the
       MPI_ALLOC_MEM function.

       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 following info key is supported:

       no_locks  If MPI_Win_lock is called on a window created with this info key, the call will fail. If this info key is present, it is  assumed
		 that  the  local  window is never locked, allowing several internal checks to be skipped, permitting a more efficient implementa-
		 tion.

NOTES

       Common choices for disp_unit are 1 (no scaling), and (in C syntax) sizeof(type), for a window that consists of an array of elements of type
       type.  The  later choice will allow one to use array indices in RMA calls, and have those scaled correctly to byte displacements, even in a
       heterogeneous environment.

       Use memory allocated by MPI_Alloc_mem to guarantee properly aligned window boundaries (such as word, double-word, cache line,  page  frame,
       and so on).

FORTRAN 77 NOTES
       The  MPI  standard  prescribes portable Fortran syntax for the SIZE argument only for Fortran 90. FORTRAN 77 users may use the non-portable
       syntax

	    INTEGER*MPI_ADDRESS_KIND SIZE

       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.

Open MPI 1.2							    March 2007						  MPI_Win_create(3OpenMPI)