[97] | 1 | .\"Copyright 2006-2008 Sun Microsystems, Inc. |
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| 2 | .\"Copyright (c) 1996 Thinking Machines |
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| 3 | .TH MPI_Type_create_f90_integer 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 | .nf |
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| 7 | \fBMPI_Type_create_f90_integer\fP \- Returns a bounded MPI integer datatype |
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| 8 | |
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| 9 | .SH SYNTAX |
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| 10 | .ft R |
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| 11 | |
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| 12 | .SH C Syntax |
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| 13 | .nf |
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| 14 | #include <mpi.h> |
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| 15 | int MPI_Type_create_f90_integer(int \fIr\fP, MPI_Datatype *\fInewtype\fP) |
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| 16 | |
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| 17 | .SH Fortran Syntax |
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| 18 | .nf |
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| 19 | INCLUDE 'mpif.h' |
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| 20 | MPI_TYPE_CREATE_F90_INTEGER (\fIR, NEWTYPE, IERROR\fP) |
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| 21 | INTEGER \fIR, NEWTYPE, IERROR\fP |
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| 22 | |
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| 23 | .SH C++ Syntax |
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| 24 | .nf |
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| 25 | #include <mpi.h> |
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| 26 | static MPI::Datatype MPI::Datatype::Create_f90_integer(int \fIr\fP) |
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| 27 | |
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| 28 | .SH INPUT PARAMETER |
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| 29 | .ft R |
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| 30 | .TP 1i |
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| 31 | r |
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| 32 | Precision, in decimal digits (integer). |
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| 33 | |
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| 34 | .SH OUTPUT PARAMETERS |
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| 35 | .ft R |
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| 36 | .TP 1i |
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| 37 | newtype |
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| 38 | New data type (handle). |
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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 function provides a way to declare KIND-parameterized INTEGER MPI |
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| 46 | datatypes. The argument is interpreted in a similar fashion to the F90 |
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| 47 | function SELECTED_INT_KIND: \fIr\fP must be a scalar integer, and |
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| 48 | represents the desired level of numerical precision, in decimal |
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| 49 | digits. |
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| 50 | |
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| 51 | .SH NOTES |
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| 52 | .ft R |
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| 53 | It is erroneous to supply a value for \fIr\fP not supported by the |
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| 54 | compiler. |
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| 55 | .sp |
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| 56 | The Fortran function SELECTED_INT_KIND maps a large number of \fIr\fP |
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| 57 | values to a much smaller number of KIND parameters supported by the |
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| 58 | compiler. KIND parameters are not specified by the language and are |
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| 59 | not portable. From the point of view of the language, variables of the |
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| 60 | same base type and KIND parameter are equivalent, even if their KIND |
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| 61 | parameters were generated by different \fIr\fP arguments to |
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| 62 | SELECTED_INT_KIND. However, to help facilitate interoperability in a |
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| 63 | heterogeneous environment, equivalency is more strictly defined for |
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| 64 | datatypes returned by MPI_Type_create_f90_integer. Two MPI datatypes, |
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| 65 | each generated by this function, will match if and only if they have |
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| 66 | identical values for \fIr\fP. |
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| 67 | .sp |
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| 68 | The interaction between the datatypes returned by this function and |
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| 69 | the external32 data representation \- used by MPI_Pack_external, |
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| 70 | MPI_Unpack_external and many MPI_File functions \- is subtle. The |
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| 71 | external32 representation of returned datatypes is as follows. |
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| 72 | .sp |
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| 73 | .nf |
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| 74 | if (\fIr\fP > 38): |
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| 75 | external32 size = n/a (undefined) |
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| 76 | else if (\fIr\fP > 18): |
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| 77 | external32 size = 16 |
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| 78 | else if (\fIr\fP > 9): |
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| 79 | external32 size = 8 |
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| 80 | else if (\fIr\fP > 4): |
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| 81 | external32 size = 4 |
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| 82 | else if (\fIr\fP > 2): |
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| 83 | external32 size = 2 |
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| 84 | else: |
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| 85 | external32 size = 1 |
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| 86 | .fi |
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| 87 | .sp |
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| 88 | If the external32 representation of a datatype is undefined, so are |
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| 89 | the results of using that datatype in operations that require the |
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| 90 | external32 format. Care should be taken not to use incompatible |
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| 91 | datatypes indirectly, e.g., as part of another datatype or through a |
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| 92 | duplicated datatype, in these functions. |
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| 93 | .sp |
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| 94 | If a variable is declared specifying a nondefault KIND value that was |
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| 95 | not obtained with SELECTED_INT_KIND (i.e., \fIr\fP is unknown), the |
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| 96 | only way to obtain a matching MPI datatype is to use the functions |
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| 97 | MPI_Sizeof and MPI_Type_match_size. |
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| 98 | |
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| 99 | .SH ERRORS |
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| 100 | .ft R |
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| 101 | Almost all MPI routines return an error value; C routines as |
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| 102 | the value of the function and Fortran routines in the last argument. C++ |
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| 103 | functions do not return errors. If the default error handler is set to |
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| 104 | MPI::ERRORS_THROW_EXCEPTIONS, then on error the C++ exception mechanism |
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| 105 | will be used to throw an MPI:Exception object. |
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| 106 | .sp |
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| 107 | Before the error value is returned, the current MPI error handler is |
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| 108 | called. By default, this error handler aborts the MPI job, except for |
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| 109 | I/O function errors. The error handler may be changed with |
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| 110 | MPI_Comm_set_errhandler; the predefined error handler MPI_ERRORS_RETURN |
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| 111 | may be used to cause error values to be returned. Note that MPI does not |
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| 112 | guarantee that an MPI program can continue past an error. |
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| 113 | .sp |
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| 114 | See the MPI man page for a full list of MPI error codes. |
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| 115 | |
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| 116 | .SH SEE ALSO |
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| 117 | .ft R |
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| 118 | .nf |
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| 119 | MPI_Pack_external |
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| 120 | MPI_Sizeof |
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| 121 | MPI_Type_match_size |
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| 122 | MPI_Unpack_external |
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| 123 | SELECTED_INT_KIND |
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| 124 | |
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