109 lines
5.2 KiB
HTML
109 lines
5.2 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
|
<html>
|
|
<!-- This manual is for FFTW
|
|
(version 3.3.10, 10 December 2020).
|
|
|
|
Copyright (C) 2003 Matteo Frigo.
|
|
|
|
Copyright (C) 2003 Massachusetts Institute of Technology.
|
|
|
|
Permission is granted to make and distribute verbatim copies of this
|
|
manual provided the copyright notice and this permission notice are
|
|
preserved on all copies.
|
|
|
|
Permission is granted to copy and distribute modified versions of this
|
|
manual under the conditions for verbatim copying, provided that the
|
|
entire resulting derived work is distributed under the terms of a
|
|
permission notice identical to this one.
|
|
|
|
Permission is granted to copy and distribute translations of this manual
|
|
into another language, under the above conditions for modified versions,
|
|
except that this permission notice may be stated in a translation
|
|
approved by the Free Software Foundation. -->
|
|
<!-- Created by GNU Texinfo 6.7, http://www.gnu.org/software/texinfo/ -->
|
|
<head>
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
|
|
<title>Multi-threaded FFTW (FFTW 3.3.10)</title>
|
|
|
|
<meta name="description" content="Multi-threaded FFTW (FFTW 3.3.10)">
|
|
<meta name="keywords" content="Multi-threaded FFTW (FFTW 3.3.10)">
|
|
<meta name="resource-type" content="document">
|
|
<meta name="distribution" content="global">
|
|
<meta name="Generator" content="makeinfo">
|
|
<link href="index.html" rel="start" title="Top">
|
|
<link href="Concept-Index.html" rel="index" title="Concept Index">
|
|
<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
|
|
<link href="index.html" rel="up" title="Top">
|
|
<link href="Installation-and-Supported-Hardware_002fSoftware.html" rel="next" title="Installation and Supported Hardware/Software">
|
|
<link href="Multi_002ddimensional-Transforms.html" rel="prev" title="Multi-dimensional Transforms">
|
|
<style type="text/css">
|
|
<!--
|
|
a.summary-letter {text-decoration: none}
|
|
blockquote.indentedblock {margin-right: 0em}
|
|
div.display {margin-left: 3.2em}
|
|
div.example {margin-left: 3.2em}
|
|
div.lisp {margin-left: 3.2em}
|
|
kbd {font-style: oblique}
|
|
pre.display {font-family: inherit}
|
|
pre.format {font-family: inherit}
|
|
pre.menu-comment {font-family: serif}
|
|
pre.menu-preformatted {font-family: serif}
|
|
span.nolinebreak {white-space: nowrap}
|
|
span.roman {font-family: initial; font-weight: normal}
|
|
span.sansserif {font-family: sans-serif; font-weight: normal}
|
|
ul.no-bullet {list-style: none}
|
|
-->
|
|
</style>
|
|
|
|
|
|
</head>
|
|
|
|
<body lang="en">
|
|
<span id="Multi_002dthreaded-FFTW"></span><div class="header">
|
|
<p>
|
|
Next: <a href="Distributed_002dmemory-FFTW-with-MPI.html" accesskey="n" rel="next">Distributed-memory FFTW with MPI</a>, Previous: <a href="FFTW-Reference.html" accesskey="p" rel="prev">FFTW Reference</a>, Up: <a href="index.html" accesskey="u" rel="up">Top</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html" title="Index" rel="index">Index</a>]</p>
|
|
</div>
|
|
<hr>
|
|
<span id="Multi_002dthreaded-FFTW-1"></span><h2 class="chapter">5 Multi-threaded FFTW</h2>
|
|
|
|
<span id="index-parallel-transform"></span>
|
|
<p>In this chapter we document the parallel FFTW routines for
|
|
shared-memory parallel hardware. These routines, which support
|
|
parallel one- and multi-dimensional transforms of both real and
|
|
complex data, are the easiest way to take advantage of multiple
|
|
processors with FFTW. They work just like the corresponding
|
|
uniprocessor transform routines, except that you have an extra
|
|
initialization routine to call, and there is a routine to set the
|
|
number of threads to employ. Any program that uses the uniprocessor
|
|
FFTW can therefore be trivially modified to use the multi-threaded
|
|
FFTW.
|
|
</p>
|
|
<p>A shared-memory machine is one in which all CPUs can directly access
|
|
the same main memory, and such machines are now common due to the
|
|
ubiquity of multi-core CPUs. FFTW’s multi-threading support allows
|
|
you to utilize these additional CPUs transparently from a single
|
|
program. However, this does not necessarily translate into
|
|
performance gains—when multiple threads/CPUs are employed, there is
|
|
an overhead required for synchronization that may outweigh the
|
|
computatational parallelism. Therefore, you can only benefit from
|
|
threads if your problem is sufficiently large.
|
|
<span id="index-shared_002dmemory"></span>
|
|
<span id="index-threads"></span>
|
|
</p>
|
|
<table class="menu" border="0" cellspacing="0">
|
|
<tr><td align="left" valign="top">• <a href="Installation-and-Supported-Hardware_002fSoftware.html" accesskey="1">Installation and Supported Hardware/Software</a></td><td> </td><td align="left" valign="top">
|
|
</td></tr>
|
|
<tr><td align="left" valign="top">• <a href="Usage-of-Multi_002dthreaded-FFTW.html" accesskey="2">Usage of Multi-threaded FFTW</a></td><td> </td><td align="left" valign="top">
|
|
</td></tr>
|
|
<tr><td align="left" valign="top">• <a href="How-Many-Threads-to-Use_003f.html" accesskey="3">How Many Threads to Use?</a></td><td> </td><td align="left" valign="top">
|
|
</td></tr>
|
|
<tr><td align="left" valign="top">• <a href="Thread-safety.html" accesskey="4">Thread safety</a></td><td> </td><td align="left" valign="top">
|
|
</td></tr>
|
|
</table>
|
|
|
|
|
|
|
|
|
|
</body>
|
|
</html>
|