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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 24 <head>
cannam@167 25 <title>FFTW 3.3.8: Distributed-memory FFTW with MPI</title>
cannam@167 26
cannam@167 27 <meta name="description" content="FFTW 3.3.8: Distributed-memory FFTW with MPI">
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cannam@167 37 <link href="FFTW-MPI-Installation.html#FFTW-MPI-Installation" rel="next" title="FFTW MPI Installation">
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cannam@167 68 </head>
cannam@167 69
cannam@167 70 <body lang="en">
cannam@167 71 <a name="Distributed_002dmemory-FFTW-with-MPI"></a>
cannam@167 72 <div class="header">
cannam@167 73 <p>
cannam@167 74 Next: <a href="Calling-FFTW-from-Modern-Fortran.html#Calling-FFTW-from-Modern-Fortran" accesskey="n" rel="next">Calling FFTW from Modern Fortran</a>, Previous: <a href="Multi_002dthreaded-FFTW.html#Multi_002dthreaded-FFTW" accesskey="p" rel="prev">Multi-threaded FFTW</a>, Up: <a href="index.html#Top" accesskey="u" rel="up">Top</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="Distributed_002dmemory-FFTW-with-MPI-1"></a>
cannam@167 78 <h2 class="chapter">6 Distributed-memory FFTW with MPI</h2>
cannam@167 79 <a name="index-MPI"></a>
cannam@167 80
cannam@167 81 <a name="index-parallel-transform-1"></a>
cannam@167 82 <p>In this chapter we document the parallel FFTW routines for parallel
cannam@167 83 systems supporting the MPI message-passing interface. Unlike the
cannam@167 84 shared-memory threads described in the previous chapter, MPI allows
cannam@167 85 you to use <em>distributed-memory</em> parallelism, where each CPU has
cannam@167 86 its own separate memory, and which can scale up to clusters of many
cannam@167 87 thousands of processors. This capability comes at a price, however:
cannam@167 88 each process only stores a <em>portion</em> of the data to be
cannam@167 89 transformed, which means that the data structures and
cannam@167 90 programming-interface are quite different from the serial or threads
cannam@167 91 versions of FFTW.
cannam@167 92 <a name="index-data-distribution"></a>
cannam@167 93 </p>
cannam@167 94
cannam@167 95 <p>Distributed-memory parallelism is especially useful when you are
cannam@167 96 transforming arrays so large that they do not fit into the memory of a
cannam@167 97 single processor. The storage per-process required by FFTW&rsquo;s MPI
cannam@167 98 routines is proportional to the total array size divided by the number
cannam@167 99 of processes. Conversely, distributed-memory parallelism can easily
cannam@167 100 pose an unacceptably high communications overhead for small problems;
cannam@167 101 the threshold problem size for which parallelism becomes advantageous
cannam@167 102 will depend on the precise problem you are interested in, your
cannam@167 103 hardware, and your MPI implementation.
cannam@167 104 </p>
cannam@167 105 <p>A note on terminology: in MPI, you divide the data among a set of
cannam@167 106 &ldquo;processes&rdquo; which each run in their own memory address space.
cannam@167 107 Generally, each process runs on a different physical processor, but
cannam@167 108 this is not required. A set of processes in MPI is described by an
cannam@167 109 opaque data structure called a &ldquo;communicator,&rdquo; the most common of
cannam@167 110 which is the predefined communicator <code>MPI_COMM_WORLD</code> which
cannam@167 111 refers to <em>all</em> processes. For more information on these and
cannam@167 112 other concepts common to all MPI programs, we refer the reader to the
cannam@167 113 documentation at <a href="http://www.mcs.anl.gov/research/projects/mpi/">the MPI home
cannam@167 114 page</a>.
cannam@167 115 <a name="index-MPI-communicator"></a>
cannam@167 116 <a name="index-MPI_005fCOMM_005fWORLD"></a>
cannam@167 117 </p>
cannam@167 118
cannam@167 119 <p>We assume in this chapter that the reader is familiar with the usage
cannam@167 120 of the serial (uniprocessor) FFTW, and focus only on the concepts new
cannam@167 121 to the MPI interface.
cannam@167 122 </p>
cannam@167 123 <table class="menu" border="0" cellspacing="0">
cannam@167 124 <tr><td align="left" valign="top">&bull; <a href="FFTW-MPI-Installation.html#FFTW-MPI-Installation" accesskey="1">FFTW MPI Installation</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
cannam@167 125 </td></tr>
cannam@167 126 <tr><td align="left" valign="top">&bull; <a href="Linking-and-Initializing-MPI-FFTW.html#Linking-and-Initializing-MPI-FFTW" accesskey="2">Linking and Initializing MPI FFTW</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
cannam@167 127 </td></tr>
cannam@167 128 <tr><td align="left" valign="top">&bull; <a href="2d-MPI-example.html#g_t2d-MPI-example" accesskey="3">2d MPI example</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
cannam@167 129 </td></tr>
cannam@167 130 <tr><td align="left" valign="top">&bull; <a href="MPI-Data-Distribution.html#MPI-Data-Distribution" accesskey="4">MPI Data Distribution</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
cannam@167 131 </td></tr>
cannam@167 132 <tr><td align="left" valign="top">&bull; <a href="Multi_002ddimensional-MPI-DFTs-of-Real-Data.html#Multi_002ddimensional-MPI-DFTs-of-Real-Data" accesskey="5">Multi-dimensional MPI DFTs of Real Data</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
cannam@167 133 </td></tr>
cannam@167 134 <tr><td align="left" valign="top">&bull; <a href="Other-Multi_002ddimensional-Real_002ddata-MPI-Transforms.html#Other-Multi_002ddimensional-Real_002ddata-MPI-Transforms" accesskey="6">Other Multi-dimensional Real-data MPI Transforms</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
cannam@167 135 </td></tr>
cannam@167 136 <tr><td align="left" valign="top">&bull; <a href="FFTW-MPI-Transposes.html#FFTW-MPI-Transposes" accesskey="7">FFTW MPI Transposes</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
cannam@167 137 </td></tr>
cannam@167 138 <tr><td align="left" valign="top">&bull; <a href="FFTW-MPI-Wisdom.html#FFTW-MPI-Wisdom" accesskey="8">FFTW MPI Wisdom</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
cannam@167 139 </td></tr>
cannam@167 140 <tr><td align="left" valign="top">&bull; <a href="Avoiding-MPI-Deadlocks.html#Avoiding-MPI-Deadlocks" accesskey="9">Avoiding MPI Deadlocks</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
cannam@167 141 </td></tr>
cannam@167 142 <tr><td align="left" valign="top">&bull; <a href="FFTW-MPI-Performance-Tips.html#FFTW-MPI-Performance-Tips">FFTW MPI Performance Tips</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
cannam@167 143 </td></tr>
cannam@167 144 <tr><td align="left" valign="top">&bull; <a href="Combining-MPI-and-Threads.html#Combining-MPI-and-Threads">Combining MPI and Threads</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
cannam@167 145 </td></tr>
cannam@167 146 <tr><td align="left" valign="top">&bull; <a href="FFTW-MPI-Reference.html#FFTW-MPI-Reference">FFTW MPI Reference</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
cannam@167 147 </td></tr>
cannam@167 148 <tr><td align="left" valign="top">&bull; <a href="FFTW-MPI-Fortran-Interface.html#FFTW-MPI-Fortran-Interface">FFTW MPI Fortran Interface</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
cannam@167 149 </td></tr>
cannam@167 150 </table>
cannam@167 151
cannam@167 152 <hr>
cannam@167 153 <div class="header">
cannam@167 154 <p>
cannam@167 155 Next: <a href="Calling-FFTW-from-Modern-Fortran.html#Calling-FFTW-from-Modern-Fortran" accesskey="n" rel="next">Calling FFTW from Modern Fortran</a>, Previous: <a href="Multi_002dthreaded-FFTW.html#Multi_002dthreaded-FFTW" accesskey="p" rel="prev">Multi-threaded FFTW</a>, Up: <a href="index.html#Top" accesskey="u" rel="up">Top</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@167 156 </div>
cannam@167 157
cannam@167 158
cannam@167 159
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cannam@167 161 </html>