78 строки
3.1 KiB
Groff
78 строки
3.1 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_Comm_test_inter 3OpenMPI "September 2006" "Open MPI 1.2" " "
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.SH NAME
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\fBMPI_Comm_test_inter \fP \- Tests to see if a comm is an intercommunicator.
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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_test_inter(MPI_Comm \fIcomm\fP, int\fI *flag\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_TEST_INTER(\fICOMM, FLAG, IERROR\fP)
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INTEGER \fICOMM, IERROR\fP
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LOGICAL \fIFLAG \fP
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.SH C++ Syntax
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.nf
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#include <mpi.h>
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bool Comm::Is_inter() 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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flag (Logical.)
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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 local routine allows the calling process to determine the type of a communicator. It returns true for an intercommunicator, false for an intracommunicator.
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.sp
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The type of communicator also affects the value returned by three other functions. When dealing with an intracommunicator (enables communication within a single group), the functions listed below return the expected values, group size, group, and rank. When dealing with an inter-communicator, however, they return the following values:
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.sp
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.nf
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MPI_Comm_size Returns the size of the local group.
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MPI_Comm_group Returns the local group.
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MPI_Comm_rank Returns the rank in the local group.
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.fi
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.sp
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To return the remote group and remote group size of an inter-communicator, use the MPI_Comm_remote_group and MPI_Comm_remote_size functions.
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.sp
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The operation MPI_Comm_compare is valid for intercommunicators. Both communicators must be either intra- or intercommunicators, or else MPI_UNEQUAL results. Both corresponding local and remote groups must compare correctly to get the results MPI_CONGRUENT and MPI_SIMILAR. In particular, it is possible for MPI_SIMILAR to result because either the local or remote groups were similar but not identical.
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.sp
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The following accessors provide consistent access to the remote group of an
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intercommunicator: MPI_Comm_remote_size, MPI_Comm_remote_group.
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.sp
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The intercommunicator accessors (MPI_Comm_test_inter, MPI_Comm_remote_size, MPI_Comm_remote_group) are all local operations.
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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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.nf
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MPI_Comm_remote_group
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MPI_Comm_remote_size
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MPI_Intercomm_create
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MPI_Intercomm_merge
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' @(#)MPI_Comm_test_inter.3 1.22 06/03/09
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