190 lines
4.5 KiB
Groff
190 lines
4.5 KiB
Groff
.TH MPI_Ialltoallw 3 "2/3/2025" " " "MPI"
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.SH NAME
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MPI_Ialltoallw \- Nonblocking generalized all-to-all communication allowing different datatypes, counts, and displacements for each partner
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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_Ialltoallw(const void *sendbuf, const int sendcounts[],
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const int sdispls[], const MPI_Datatype sendtypes[],
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void *recvbuf, const int recvcounts[], const int rdispls[],
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const MPI_Datatype recvtypes[], MPI_Comm comm,
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MPI_Request *request)
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.fi
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.nf
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int MPI_Ialltoallw_c(const void *sendbuf, const MPI_Count sendcounts[],
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const MPI_Aint sdispls[], const MPI_Datatype sendtypes[],
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void *recvbuf, const MPI_Count recvcounts[],
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const MPI_Aint rdispls[], const MPI_Datatype recvtypes[],
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MPI_Comm comm, MPI_Request *request)
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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 sendbuf
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- starting address of send buffer (choice)
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.PD 1
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.PD 0
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.TP
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.B sendcounts
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- integer array (of length group size) specifying the number of elements to send to each rank (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 sdispls
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- integer array (of length group size). Entry j specifies the displacement in bytes (relative to sendbuf) from which to take the outgoing data destined for process j (integer)
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.PD 1
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.PD 0
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.TP
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.B sendtypes
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- array of datatypes (of length group size). Entry j specifies the type of data to send to process j (handle)
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.PD 1
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.PD 0
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.TP
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.B recvcounts
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- integer array (of length group size) specifying the number of elements that can be received from each rank (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 rdispls
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- integer array (of length group size). Entry i specifies the displacement in bytes (relative to recvbuf) at which to place the incoming data from process i (integer)
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.PD 1
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.PD 0
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.TP
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.B recvtypes
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- array of datatypes (of length group size). Entry i specifies the type of data received from process i (handle)
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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 (handle)
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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 recvbuf
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- address of receive buffer (choice)
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.PD 1
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.PD 0
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.TP
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.B request
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- communication request (handle)
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.PD 1
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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_BUFFER
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- Invalid buffer pointer. Usually a null buffer where
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one is not 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_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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