174 lines
3.8 KiB
Groff
174 lines
3.8 KiB
Groff
.TH MPI_Pack 3 "2/3/2025" " " "MPI"
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.SH NAME
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MPI_Pack \- Packs a datatype into contiguous memory
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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_Pack(const void *inbuf, int incount, MPI_Datatype datatype,
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void *outbuf, int outsize, int *position, MPI_Comm comm)
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.fi
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.nf
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int MPI_Pack_c(const void *inbuf, MPI_Count incount, MPI_Datatype datatype,
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void *outbuf, MPI_Count outsize, MPI_Count *position,
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MPI_Comm comm)
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.fi
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.SH INPUT PARAMETERS
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.PD 0
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.TP
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.B inbuf
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- input buffer start (choice)
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.PD 1
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.PD 0
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.TP
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.B incount
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- number of input data items (non-negative integer)
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.PD 1
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.PD 0
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.TP
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.B datatype
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- datatype of each input data item (handle)
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.PD 1
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.PD 0
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.TP
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.B outsize
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- output buffer size, in bytes (non-negative integer)
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.PD 1
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.PD 0
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.TP
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.B comm
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- communicator for packed message (handle)
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.PD 1
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.SH INPUT/OUTPUT PARAMETERS
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.PD 0
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.TP
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.B position
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- current position in buffer, in bytes (integer)
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.PD 1
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.SH OUTPUT PARAMETERS
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.PD 0
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.TP
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.B outbuf
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- output buffer start (choice)
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.PD 1
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.SH NOTES (FROM THE SPECIFICATIONS)
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The input value of position is the first location in the output buffer to be
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used for packing. position is incremented by the size of the packed message,
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and the output value of position is the first location in the output buffer
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following the locations occupied by the packed message. The comm argument is
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the communicator that will be subsequently used for sending the packed
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message.
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.SH THREAD AND INTERRUPT SAFETY
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This routine is thread-safe. This means that this routine may be
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safely used by multiple threads without the need for any user-provided
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thread locks. However, the routine is not interrupt safe. Typically,
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this is due to the use of memory allocation routines such as
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.I malloc
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or other non-MPICH runtime routines that are themselves not interrupt-safe.
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.SH NOTES FOR FORTRAN
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All MPI routines in Fortran (except for
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.I MPI_WTIME
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and
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.I MPI_WTICK
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) have
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an additional argument
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.I ierr
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at the end of the argument list.
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.I ierr
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is an integer and has the same meaning as the return value of the routine
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in C. In Fortran, MPI routines are subroutines, and are invoked with the
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.I call
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statement.
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All MPI objects (e.g.,
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.I MPI_Datatype
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,
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.I MPI_Comm
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) are of type
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.I INTEGER
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in Fortran.
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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_ARG
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- Invalid argument. Some argument is invalid and is not
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identified by a specific error class (e.g.,
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.I MPI_ERR_RANK
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).
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.PD 1
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.PD 0
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.TP
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.B MPI_ERR_COMM
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- Invalid communicator. A common error is to use a null
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communicator in a call (not even allowed in
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.I MPI_Comm_rank
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).
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.PD 1
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.PD 0
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.TP
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.B MPI_ERR_COUNT
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- Invalid count argument. Count arguments must be
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non-negative; a count of zero is often valid.
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.PD 1
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.PD 0
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.TP
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.B MPI_ERR_TYPE
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- Invalid datatype argument. Additionally, this error can
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occur if an uncommitted MPI_Datatype (see
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.I MPI_Type_commit
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) is used
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in a communication call.
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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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