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Add FFTW 3.3.8 source, and a Linux build
author Chris Cannam <cannam@all-day-breakfast.com>
date Tue, 19 Nov 2019 14:52:55 +0000
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cannam@167 1 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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cannam@167 3 <!-- This manual is for FFTW
cannam@167 4 (version 3.3.8, 24 May 2018).
cannam@167 5
cannam@167 6 Copyright (C) 2003 Matteo Frigo.
cannam@167 7
cannam@167 8 Copyright (C) 2003 Massachusetts Institute of Technology.
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cannam@167 10 Permission is granted to make and distribute verbatim copies of this
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cannam@167 23 <!-- Created by GNU Texinfo 6.3, http://www.gnu.org/software/texinfo/ -->
cannam@167 24 <head>
cannam@167 25 <title>FFTW 3.3.8: Avoiding MPI Deadlocks</title>
cannam@167 26
cannam@167 27 <meta name="description" content="FFTW 3.3.8: Avoiding MPI Deadlocks">
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cannam@167 34 <link href="Concept-Index.html#Concept-Index" rel="index" title="Concept Index">
cannam@167 35 <link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
cannam@167 36 <link href="Distributed_002dmemory-FFTW-with-MPI.html#Distributed_002dmemory-FFTW-with-MPI" rel="up" title="Distributed-memory FFTW with MPI">
cannam@167 37 <link href="FFTW-MPI-Performance-Tips.html#FFTW-MPI-Performance-Tips" rel="next" title="FFTW MPI Performance Tips">
cannam@167 38 <link href="FFTW-MPI-Wisdom.html#FFTW-MPI-Wisdom" rel="prev" title="FFTW MPI Wisdom">
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cannam@167 66
cannam@167 67
cannam@167 68 </head>
cannam@167 69
cannam@167 70 <body lang="en">
cannam@167 71 <a name="Avoiding-MPI-Deadlocks"></a>
cannam@167 72 <div class="header">
cannam@167 73 <p>
cannam@167 74 Next: <a href="FFTW-MPI-Performance-Tips.html#FFTW-MPI-Performance-Tips" accesskey="n" rel="next">FFTW MPI Performance Tips</a>, Previous: <a href="FFTW-MPI-Wisdom.html#FFTW-MPI-Wisdom" accesskey="p" rel="prev">FFTW MPI Wisdom</a>, Up: <a href="Distributed_002dmemory-FFTW-with-MPI.html#Distributed_002dmemory-FFTW-with-MPI" accesskey="u" rel="up">Distributed-memory FFTW with MPI</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
cannam@167 75 </div>
cannam@167 76 <hr>
cannam@167 77 <a name="Avoiding-MPI-Deadlocks-1"></a>
cannam@167 78 <h3 class="section">6.9 Avoiding MPI Deadlocks</h3>
cannam@167 79 <a name="index-deadlock"></a>
cannam@167 80
cannam@167 81 <p>An MPI program can <em>deadlock</em> if one process is waiting for a
cannam@167 82 message from another process that never gets sent. To avoid deadlocks
cannam@167 83 when using FFTW&rsquo;s MPI routines, it is important to know which
cannam@167 84 functions are <em>collective</em>: that is, which functions must
cannam@167 85 <em>always</em> be called in the <em>same order</em> from <em>every</em>
cannam@167 86 process in a given communicator. (For example, <code>MPI_Barrier</code> is
cannam@167 87 the canonical example of a collective function in the MPI standard.)
cannam@167 88 <a name="index-collective-function-2"></a>
cannam@167 89 <a name="index-MPI_005fBarrier"></a>
cannam@167 90 </p>
cannam@167 91
cannam@167 92 <p>The functions in FFTW that are <em>always</em> collective are: every
cannam@167 93 function beginning with &lsquo;<samp>fftw_mpi_plan</samp>&rsquo;, as well as
cannam@167 94 <code>fftw_mpi_broadcast_wisdom</code> and <code>fftw_mpi_gather_wisdom</code>.
cannam@167 95 Also, the following functions from the ordinary FFTW interface are
cannam@167 96 collective when they are applied to a plan created by an
cannam@167 97 &lsquo;<samp>fftw_mpi_plan</samp>&rsquo; function: <code>fftw_execute</code>,
cannam@167 98 <code>fftw_destroy_plan</code>, and <code>fftw_flops</code>.
cannam@167 99 <a name="index-fftw_005fexecute-4"></a>
cannam@167 100 <a name="index-fftw_005fdestroy_005fplan-2"></a>
cannam@167 101 <a name="index-fftw_005fflops-1"></a>
cannam@167 102 </p>
cannam@167 103
cannam@167 104
cannam@167 105
cannam@167 106 </body>
cannam@167 107 </html>