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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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1 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
2 <html>
3 <!-- This manual is for FFTW
4 (version 3.3.8, 24 May 2018).
5
6 Copyright (C) 2003 Matteo Frigo.
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8 Copyright (C) 2003 Massachusetts Institute of Technology.
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10 Permission is granted to make and distribute verbatim copies of this
11 manual provided the copyright notice and this permission notice are
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15 manual under the conditions for verbatim copying, provided that the
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24 <head>
25 <title>FFTW 3.3.8: Multi-threaded FFTW</title>
26
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71 <a name="Multi_002dthreaded-FFTW"></a>
72 <div class="header">
73 <p>
74 Next: <a href="Distributed_002dmemory-FFTW-with-MPI.html#Distributed_002dmemory-FFTW-with-MPI" accesskey="n" rel="next">Distributed-memory FFTW with MPI</a>, Previous: <a href="FFTW-Reference.html#FFTW-Reference" accesskey="p" rel="prev">FFTW Reference</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>
75 </div>
76 <hr>
77 <a name="Multi_002dthreaded-FFTW-1"></a>
78 <h2 class="chapter">5 Multi-threaded FFTW</h2>
79
80 <a name="index-parallel-transform"></a>
81 <p>In this chapter we document the parallel FFTW routines for
82 shared-memory parallel hardware. These routines, which support
83 parallel one- and multi-dimensional transforms of both real and
84 complex data, are the easiest way to take advantage of multiple
85 processors with FFTW. They work just like the corresponding
86 uniprocessor transform routines, except that you have an extra
87 initialization routine to call, and there is a routine to set the
88 number of threads to employ. Any program that uses the uniprocessor
89 FFTW can therefore be trivially modified to use the multi-threaded
90 FFTW.
91 </p>
92 <p>A shared-memory machine is one in which all CPUs can directly access
93 the same main memory, and such machines are now common due to the
94 ubiquity of multi-core CPUs. FFTW&rsquo;s multi-threading support allows
95 you to utilize these additional CPUs transparently from a single
96 program. However, this does not necessarily translate into
97 performance gains&mdash;when multiple threads/CPUs are employed, there is
98 an overhead required for synchronization that may outweigh the
99 computatational parallelism. Therefore, you can only benefit from
100 threads if your problem is sufficiently large.
101 <a name="index-shared_002dmemory"></a>
102 <a name="index-threads"></a>
103 </p>
104 <table class="menu" border="0" cellspacing="0">
105 <tr><td align="left" valign="top">&bull; <a href="Installation-and-Supported-Hardware_002fSoftware.html#Installation-and-Supported-Hardware_002fSoftware" accesskey="1">Installation and Supported Hardware/Software</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
106 </td></tr>
107 <tr><td align="left" valign="top">&bull; <a href="Usage-of-Multi_002dthreaded-FFTW.html#Usage-of-Multi_002dthreaded-FFTW" accesskey="2">Usage of Multi-threaded FFTW</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
108 </td></tr>
109 <tr><td align="left" valign="top">&bull; <a href="How-Many-Threads-to-Use_003f.html#How-Many-Threads-to-Use_003f" accesskey="3">How Many Threads to Use?</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
110 </td></tr>
111 <tr><td align="left" valign="top">&bull; <a href="Thread-safety.html#Thread-safety" accesskey="4">Thread safety</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
112 </td></tr>
113 </table>
114
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116
117
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119 </html>