110 lines
2.1 KiB
Groff
110 lines
2.1 KiB
Groff
.TH MPI_Init 3 "2/3/2025" " " "MPI"
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.SH NAME
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MPI_Init \- Initialize the MPI execution environment
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.SH SYNOPSIS
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.nf
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.fi
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.nf
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int MPI_Init(int *argc, char ***argv)
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.fi
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.SH INPUT/OUTPUT PARAMETERS
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.PD 0
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.TP
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.B argc
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- argc (None)
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.PD 1
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.PD 0
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.TP
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.B argv
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- argv (None)
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.PD 1
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.SH NOTES
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The MPI standard does not say what a program can do before an
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.I MPI_INIT
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or
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after an
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.I MPI_FINALIZE
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\&.
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In the MPICH implementation, you should do
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as little as possible. In particular, avoid anything that changes the
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external state of the program, such as opening files, reading standard
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input or writing to standard output.
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.SH THREAD AND SIGNAL SAFETY
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This routine must be called by one thread only. That thread is called
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the
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.B main thread
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and must be the thread that calls
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.I MPI_Finalize
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\&.
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.SH NOTES FOR C
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As of MPI-2,
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.I MPI_Init
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will accept NULL as input parameters. Doing so
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will impact the values stored in
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.I MPI_INFO_ENV
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\&.
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.SH NOTES FOR FORTRAN
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The Fortran binding for
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.I MPI_Init
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has only the error return
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.nf
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subroutine MPI_INIT(ierr)
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integer ierr
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.fi
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.SH ERRORS
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All MPI routines (except
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.I MPI_Wtime
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and
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.I MPI_Wtick
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) return an error value;
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C routines as the value of the function and Fortran routines in the last
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argument. Before the value is returned, the current MPI error handler is
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called. By default, this error handler aborts the MPI job. The error handler
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may be changed with
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.I MPI_Comm_set_errhandler
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(for communicators),
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.I MPI_File_set_errhandler
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(for files), and
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.I MPI_Win_set_errhandler
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(for
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RMA windows). The MPI-1 routine
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.I MPI_Errhandler_set
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may be used but
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its use is deprecated. The predefined error handler
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.I MPI_ERRORS_RETURN
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may be used to cause error values to be returned.
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Note that MPI does
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.B not
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guarantee that an MPI program can continue past
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an error; however, MPI implementations will attempt to continue whenever
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possible.
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.PD 0
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.TP
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.B MPI_SUCCESS
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- No error; MPI routine completed successfully.
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.PD 1
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.PD 0
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.TP
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.B MPI_ERR_OTHER
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- Other error; use
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.I MPI_Error_string
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to get more information
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about this error code.
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.PD 1
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.SH SEE ALSO
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MPI_Init_thread, MPI_Finalize
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.br
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