77 lines
3.6 KiB
HTML
77 lines
3.6 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML3.2 EN">
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<META NAME="GENERATOR" CONTENT="DOCTEXT">
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<TITLE>MPI_Ialltoallw</TITLE>
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</HEAD>
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<BODY BGCOLOR="FFFFFF">
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<A NAME="MPI_Ialltoallw"><H1>MPI_Ialltoallw</H1></A>
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Nonblocking generalized all-to-all communication allowing different datatypes, counts, and displacements for each partner
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<H2>Synopsis</H2>
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<PRE>
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int MPI_Ialltoallw(const void *sendbuf, const int sendcounts[], const int sdispls[],
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const MPI_Datatype sendtypes[], void *recvbuf, const int recvcounts[],
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const int rdispls[], const MPI_Datatype recvtypes[], MPI_Comm comm,
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MPI_Request *request)
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</PRE>
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<H2>Input Parameters</H2>
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<DL>
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<DT><B>sendbuf </B><DD>starting address of the send buffer (choice)
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<DT><B>sendcounts </B><DD>non-negative integer array (of length group size) specifying the number of elements to send to each processor
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<DT><B>sdispls </B><DD>integer array (of length group size). Entry j specifies the displacement relative to sendbuf from which to take the outgoing data destined for process j
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<DT><B>sendtypes </B><DD>array of datatypes (of length group size). Entry j specifies the type of data to send to process j (array of handles)
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<DT><B>recvcounts </B><DD>non-negative integer array (of length group size) specifying the number of elements that can be received from each processor
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<DT><B>rdispls </B><DD>integer array (of length group size). Entry i specifies the displacement relative to recvbuf at which to place the incoming data from process i
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<DT><B>recvtypes </B><DD>array of datatypes (of length group size). Entry i specifies the type of data received from process i (array of handles)
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<DT><B>comm </B><DD>communicator (handle)
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</DL>
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<P>
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<H2>Output Parameters</H2>
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<DL>
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<DT><B>recvbuf </B><DD>starting address of the receive buffer (choice)
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<DT><B>request </B><DD>communication request (handle)
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</DL>
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<P>
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<H2>Thread and Interrupt Safety</H2>
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<P>
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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 <tt>malloc
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</tt>or other non-MPICH runtime routines that are themselves not interrupt-safe.
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<P>
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<H2>Notes for Fortran</H2>
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All MPI routines in Fortran (except for <tt>MPI_WTIME</tt> and <tt>MPI_WTICK</tt>) have
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an additional argument <tt>ierr</tt> at the end of the argument list. <tt>ierr
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</tt>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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<tt>call</tt> statement.
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<P>
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All MPI objects (e.g., <tt>MPI_Datatype</tt>, <tt>MPI_Comm</tt>) are of type <tt>INTEGER
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</tt>in Fortran.
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<P>
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<H2>Errors</H2>
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<P>
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All MPI routines (except <tt>MPI_Wtime</tt> and <tt>MPI_Wtick</tt>) 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 <tt>MPI_Comm_set_errhandler</tt> (for communicators),
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<tt>MPI_File_set_errhandler</tt> (for files), and <tt>MPI_Win_set_errhandler</tt> (for
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RMA windows). The MPI-1 routine <tt>MPI_Errhandler_set</tt> may be used but
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its use is deprecated. The predefined error handler
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<tt>MPI_ERRORS_RETURN</tt> may be used to cause error values to be returned.
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Note that MPI does <em>not</em> guarentee 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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<P>
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</BODY></HTML>
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