1 | .\"Copyright 2006-2008 Sun Microsystems, Inc. |
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2 | .\" Copyright (c) 1996 Thinking Machines Corporation |
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3 | .TH MPI_Init 3 "Dec 08, 2009" "1.4" "Open MPI" |
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4 | |
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5 | .SH NAME |
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6 | \fBMPI_Init\fP \- Initializes the MPI execution environment |
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7 | |
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8 | .SH SYNTAX |
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9 | .ft R |
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10 | |
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11 | .SH C Syntax |
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12 | .nf |
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13 | #include <mpi.h> |
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14 | int MPI_Init(int *\fIargc\fP, char ***\fIargv\fP) |
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15 | |
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16 | .SH Fortran Syntax |
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17 | .nf |
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18 | INCLUDE 'mpif.h' |
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19 | MPI_INIT(\fIIERROR\fP) |
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20 | INTEGER \fIIERROR\fP |
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21 | |
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22 | .SH C++ Syntax |
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23 | .nf |
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24 | #include <mpi.h> |
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25 | void MPI::Init(int& \fIargc\fP, char**& \fIargv\fP) |
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26 | void MPI::Init() |
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27 | |
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28 | .SH INPUT PARAMETERS |
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29 | .ft R |
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30 | .TP 1i |
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31 | argc |
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32 | C/C++ only: Pointer to the number of arguments. |
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33 | .TP 1i |
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34 | argv |
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35 | C/C++ only: Argument vector. |
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36 | |
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37 | .SH OUTPUT PARAMETER |
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38 | .ft R |
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39 | .TP 1i |
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40 | IERROR |
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41 | Fortran only: Error status (integer). |
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42 | |
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43 | .SH DESCRIPTION |
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44 | .ft R |
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45 | This routine, or MPI_Init_thread, must be called before any other MPI |
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46 | routine (apart from MPI_Initialized) is called. MPI can be initialized |
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47 | at most once; subsequent calls to MPI_Init or MPI_Init_thread are |
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48 | erroneous. |
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49 | .sp |
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50 | All MPI programs must contain a call to MPI_Init or |
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51 | MPI_Init_thread. Open MPI accepts the C/C++ \fIargc\fP and \fIargv\fP |
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52 | arguments to main, but neither modifies, interprets, nor distributes |
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53 | them: |
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54 | .sp |
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55 | .nf |
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56 | { |
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57 | /* declare variables */ |
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58 | MPI_Init(&argc, &argv); |
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59 | /* parse arguments */ |
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60 | /* main program */ |
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61 | MPI_Finalize(); |
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62 | } |
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63 | .fi |
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64 | |
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65 | .SH NOTES |
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66 | .ft R |
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67 | The Fortran version does not have provisions for \fIargc\fP and |
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68 | \fIargv\fP and takes only IERROR. |
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69 | .sp |
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70 | The MPI Standard does not say what a program can do before an MPI_Init |
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71 | or after an MPI_Finalize. In the Open MPI implementation, it should do |
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72 | as little as possible. In particular, avoid anything that changes the |
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73 | external state of the program, such as opening files, reading standard |
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74 | input, or writing to standard output. |
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75 | |
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76 | .SH ERRORS |
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77 | .ft R |
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78 | Almost all MPI routines return an error value; C routines as |
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79 | the value of the function and Fortran routines in the last argument. C++ |
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80 | functions do not return errors. If the default error handler is set to |
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81 | MPI::ERRORS_THROW_EXCEPTIONS, then on error the C++ exception mechanism |
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82 | will be used to throw an MPI:Exception object. |
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83 | .sp |
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84 | Before the error value is returned, the current MPI error handler is |
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85 | called. By default, this error handler aborts the MPI job, except for |
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86 | I/O function errors. The error handler may be changed with |
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87 | MPI_Comm_set_errhandler; the predefined error handler MPI_ERRORS_RETURN |
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88 | may be used to cause error values to be returned. Note that MPI does not |
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89 | guarantee that an MPI program can continue past an error. |
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90 | .sp |
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91 | See the MPI man page for a full list of MPI error codes. |
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92 | |
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93 | .SH SEE ALSO |
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94 | .ft R |
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95 | .nf |
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96 | MPI_Init_thread |
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97 | MPI_Initialized |
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98 | MPI_Finalize |
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99 | |
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