61 строка
2.7 KiB
Groff
61 строка
2.7 KiB
Groff
.\"Copyright 2006, Sun Microsystems, Inc.
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.\" Copyright (c) 1996 Thinking Machines Corporation
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.TH MPI_Comm_dup 3OpenMPI "September 2006" "Open MPI 1.2" " "
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.SH NAME
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\fBMPI_Comm_dup \fP \- Duplicates an existing communicator with all its cached information.
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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_Comm_dup(MPI_Comm \fIcomm\fP, MPI_Comm\fI *newcomm\fP)
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.SH Fortran Syntax
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.nf
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INCLUDE 'mpif.h'
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MPI_COMM_DUP(\fICOMM, NEWCOMM, IERROR\fP)
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INTEGER \fICOMM, NEWCOMM, IERROR\fP
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.SH C++ Syntax
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.nf
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#include <mpi.h>
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Intracomm Intracomm::Dup() const
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Intercomm Intercomm::Dup() const
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.SH INPUT PARAMETER
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.ft R
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.TP 1i
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comm
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Communicator (handle).
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.SH OUTPUT PARAMETERS
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.ft R
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.TP 1i
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newcomm
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Copy of comm (handle).
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.ft R
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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_Comm_dup duplicates the existing communicator comm with associated key
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values. For each key value, the respective copy callback function determines the attribute value associated with this key in the new communicator; one particular action that a copy callback may take is to delete the attribute from the new communicator. Returns in newcomm a new communicator with the same group, any copied cached information, but a new context (see Section 5.7.1 of the MPI-1 Standard, "Functionality").
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.SH NOTES
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This operation is used to provide a parallel
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library call with a duplicate communication space that has the same properties as the original communicator. This includes any attributes (see below) and topologies (see Chapter 6, "Process Topologies," in the MPI-1 Standard). This call is valid even if there are pending point-to-point communications involving the communicator comm. A typical call might involve an MPI_Comm_dup at the beginning of the parallel call, and an MPI_Comm_free of that duplicated communicator at the end of the call. Other models of communicator management are also possible.
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.sp
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This call applies to both intra- and intercommunicators.
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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 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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