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Add null config files
author Chris Cannam <cannam@all-day-breakfast.com>
date Mon, 02 Mar 2020 14:03:47 +0000
parents 7867fa7e1b6b
children
rev   line source
cannam@127 1 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
cannam@127 2 <html>
cannam@127 3 <!-- This manual is for FFTW
cannam@127 4 (version 3.3.5, 30 July 2016).
cannam@127 5
cannam@127 6 Copyright (C) 2003 Matteo Frigo.
cannam@127 7
cannam@127 8 Copyright (C) 2003 Massachusetts Institute of Technology.
cannam@127 9
cannam@127 10 Permission is granted to make and distribute verbatim copies of this
cannam@127 11 manual provided the copyright notice and this permission notice are
cannam@127 12 preserved on all copies.
cannam@127 13
cannam@127 14 Permission is granted to copy and distribute modified versions of this
cannam@127 15 manual under the conditions for verbatim copying, provided that the
cannam@127 16 entire resulting derived work is distributed under the terms of a
cannam@127 17 permission notice identical to this one.
cannam@127 18
cannam@127 19 Permission is granted to copy and distribute translations of this manual
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cannam@127 22 approved by the Free Software Foundation. -->
cannam@127 23 <!-- Created by GNU Texinfo 5.2, http://www.gnu.org/software/texinfo/ -->
cannam@127 24 <head>
cannam@127 25 <title>FFTW 3.3.5: Multi-threaded FFTW</title>
cannam@127 26
cannam@127 27 <meta name="description" content="FFTW 3.3.5: Multi-threaded FFTW">
cannam@127 28 <meta name="keywords" content="FFTW 3.3.5: Multi-threaded FFTW">
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cannam@127 33 <link href="index.html#Top" rel="start" title="Top">
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cannam@127 35 <link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
cannam@127 36 <link href="index.html#Top" rel="up" title="Top">
cannam@127 37 <link href="Installation-and-Supported-Hardware_002fSoftware.html#Installation-and-Supported-Hardware_002fSoftware" rel="next" title="Installation and Supported Hardware/Software">
cannam@127 38 <link href="Multi_002ddimensional-Transforms.html#Multi_002ddimensional-Transforms" rel="prev" title="Multi-dimensional Transforms">
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cannam@127 68
cannam@127 69 </head>
cannam@127 70
cannam@127 71 <body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000">
cannam@127 72 <a name="Multi_002dthreaded-FFTW"></a>
cannam@127 73 <div class="header">
cannam@127 74 <p>
cannam@127 75 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>
cannam@127 76 </div>
cannam@127 77 <hr>
cannam@127 78 <a name="Multi_002dthreaded-FFTW-1"></a>
cannam@127 79 <h2 class="chapter">5 Multi-threaded FFTW</h2>
cannam@127 80
cannam@127 81 <a name="index-parallel-transform"></a>
cannam@127 82 <p>In this chapter we document the parallel FFTW routines for
cannam@127 83 shared-memory parallel hardware. These routines, which support
cannam@127 84 parallel one- and multi-dimensional transforms of both real and
cannam@127 85 complex data, are the easiest way to take advantage of multiple
cannam@127 86 processors with FFTW. They work just like the corresponding
cannam@127 87 uniprocessor transform routines, except that you have an extra
cannam@127 88 initialization routine to call, and there is a routine to set the
cannam@127 89 number of threads to employ. Any program that uses the uniprocessor
cannam@127 90 FFTW can therefore be trivially modified to use the multi-threaded
cannam@127 91 FFTW.
cannam@127 92 </p>
cannam@127 93 <p>A shared-memory machine is one in which all CPUs can directly access
cannam@127 94 the same main memory, and such machines are now common due to the
cannam@127 95 ubiquity of multi-core CPUs. FFTW&rsquo;s multi-threading support allows
cannam@127 96 you to utilize these additional CPUs transparently from a single
cannam@127 97 program. However, this does not necessarily translate into
cannam@127 98 performance gains&mdash;when multiple threads/CPUs are employed, there is
cannam@127 99 an overhead required for synchronization that may outweigh the
cannam@127 100 computatational parallelism. Therefore, you can only benefit from
cannam@127 101 threads if your problem is sufficiently large.
cannam@127 102 <a name="index-shared_002dmemory"></a>
cannam@127 103 <a name="index-threads"></a>
cannam@127 104 </p>
cannam@127 105 <table class="menu" border="0" cellspacing="0">
cannam@127 106 <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">
cannam@127 107 </td></tr>
cannam@127 108 <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">
cannam@127 109 </td></tr>
cannam@127 110 <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">
cannam@127 111 </td></tr>
cannam@127 112 <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">
cannam@127 113 </td></tr>
cannam@127 114 </table>
cannam@127 115
cannam@127 116
cannam@127 117
cannam@127 118
cannam@127 119 </body>
cannam@127 120 </html>