69 строки
2.7 KiB
Groff
69 строки
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_create 3OpenMPI "September 2006" "Open MPI 1.2" " "
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.SH NAME
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\fBMPI_Comm_create\fP \- Creates a new communicator.
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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_create(MPI_Comm \fIcomm\fP, MPI_Group\fI group\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_CREATE(\fICOMM, GROUP, NEWCOMM, IERROR\fP)
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INTEGER \fICOMM, GROUP, NEW, 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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MPI::Intercomm MPI::Intercomm::Create(const Group& \fIgroup\fP) const
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MPI::Intracomm MPI::Intracomm::Create(const Group& \fIgroup\fP) 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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.TP 1i
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group
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Group, which is a subset of the group of comm (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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New communicator (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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This function creates a new communicator newcomm with communication group
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defined by group and a new context. The function sets \fInewcomm\fR to a new communicator that spans all the processes that are in the group. It sets \fInewcomm\fR to MPI_COMM_NULL for processes that are not in the group. The call is erroneous if not all group arguments have the same value, or if group is not a subset of the group associated with comm. Note that the call must be executed by all processes in comm, even if they do not belong to the new group.
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.sp
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.LP
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.SH NOTES
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MPI_Comm_create provides a means of making a subset of processes for the purpose of separate MIMD computation, with separate communication space. \fInewcomm\fR, which is created by MPI_Comm_create, can be used in subsequent calls to MPI_Comm_create (or other communicator constructors) to further subdivide a computation into parallel sub-computations. A more general service is provided by MPI_Comm_split.
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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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.SH SEE ALSO
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.ft R
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.sp
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MPI_Comm_split
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.sp
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MPI_Intercomm_create
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