98 строки
3.0 KiB
Groff
98 строки
3.0 KiB
Groff
.\"Copyright 2006, Sun Microsystems, Inc. All rights reserved. Use is subject to license terms.
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.\" Copyright (c) 1996 Thinking Machines Corporation
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.TH MPI_Alloc_mem 3OpenMPI "September 2006" "Open MPI 1.2" " "
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.SH NAME
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\fBMPI_Alloc_mem \fP \- Allocates a specified memory segment.
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.SH SYNTAX
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.ft R
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.SH C Syntax
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.nf
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#include <mpi.h>
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int MPI_Alloc_mem(MPI_Aint \fIsize\fP, MPI_Info \fIinfo\fP, void *\fIbaseptr\fP)
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.SH Fortran Syntax (see FORTRAN NOTES)
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.nf
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INCLUDE 'mpif.h'
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MPI_ALLOC_MEM(\fISIZE, INFO, BASEPTR, IERROR\fP)
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INTEGER \fIINFO, IERROR\fP
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INTEGER(KIND=MPI_ADDRESS_KIND) \fISIZE, BASEPTR\fP
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.SH C++ Syntax
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.nf
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#include <mpi.h>
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void* MPI::Alloc_mem(MPI::Aint \fIsize\fP, const MPI::Info& \fIinfo\fP)
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.SH INPUT PARAMETERS
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.ft R
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.TP 1i
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size
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Size of memory segment in bytes (nonnegative integer).
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.ft R
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.TP 1i
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info
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Info argument (handle).
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.SH OUTPUT PARAMETERS
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.ft R
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.TP 1i
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baseptr
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Pointer to beginning of memory segment allocated.
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.TP 1i
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IERROR
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Fortran only: Error status (integer).
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.SH DESCRIPTION
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.ft R
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MPI_Alloc_mem allocates \fIsize\fP bytes of memory. The starting address
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of this memory is returned in the variable \fIbase\fP.
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.sp
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Memory allocated by MPI_Alloc_mem is
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guaranteed to be aligned on natural boundaries (page frames).
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.SH FORTRAN NOTES
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.ft R
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There is no portable FORTRAN 77 syntax for using MPI_Alloc_mem.
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There is no portable Fortran syntax for using pointers returned
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from MPI_Alloc_mem. However, MPI_Alloc_mem can be used with
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Fortran compilers.
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.sp
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From FORTRAN 77, you can use the following non-standard
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declarations for the SIZE and BASEPTR arguments:
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.nf
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INCLUDE "mpif.h"
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INTEGER*MPI_ADDRESS_KIND SIZE, BASEPTR
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.fi
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.sp
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From either FORTRAN 77 or Fortran 90, you can use "Cray pointers"
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for the BASEPTR argument. Cray pointers are described further in
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the Fortran User's Guide and are supported by many Fortran compilers.
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For example,
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.sp
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.nf
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INCLUDE "mpif.h"
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REAL*4 A(100,100)
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POINTER (BASEPTR, A)
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INTEGER*MPI_ADDRESS_KIND SIZE
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SIZE = 4 * 100 * 100
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CALL MPI_ALLOC_MEM(SIZE,MPI_INFO_NULL,BASEPTR,IERR)
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! use A
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CALL MPI_FREE_MEM(A, IERR)
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.fi
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.SH ERRORS
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Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument. C++ functions 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.
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.sp
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Before the error value is returned, the current MPI error handler is
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called. By default, this error handler aborts the MPI job, except for I/O function errors. The error handler
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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.
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.SH SEE ALSO
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.ft R
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.sp
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MPI_Free_mem
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' @(#)MPI_Alloc_mem.3 1.17 06/03/09
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