mirror of
https://github.com/tildearrow/furnace.git
synced 2024-11-30 16:33:01 +00:00
113 lines
4.8 KiB
HTML
113 lines
4.8 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>Precision (FFTW 3.3.10)</title>
|
|
|
|
<meta name="description" content="Precision (FFTW 3.3.10)">
|
|
<meta name="keywords" content="Precision (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="Data-Types-and-Files.html" rel="up" title="Data Types and Files">
|
|
<link href="Memory-Allocation.html" rel="next" title="Memory Allocation">
|
|
<link href="Complex-numbers.html" rel="prev" title="Complex numbers">
|
|
<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="Precision"></span><div class="header">
|
|
<p>
|
|
Next: <a href="Memory-Allocation.html" accesskey="n" rel="next">Memory Allocation</a>, Previous: <a href="Complex-numbers.html" accesskey="p" rel="prev">Complex numbers</a>, Up: <a href="Data-Types-and-Files.html" accesskey="u" rel="up">Data Types and Files</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="Precision-1"></span><h4 class="subsection">4.1.2 Precision</h4>
|
|
<span id="index-precision-3"></span>
|
|
|
|
<p>You can install single and long-double precision versions of FFTW,
|
|
which replace <code>double</code> with <code>float</code> and <code>long double</code>,
|
|
respectively (see <a href="Installation-and-Customization.html">Installation and Customization</a>). To use these
|
|
interfaces, you:
|
|
</p>
|
|
<ul>
|
|
<li> Link to the single/long-double libraries; on Unix, <code>-lfftw3f</code> or
|
|
<code>-lfftw3l</code> instead of (or in addition to) <code>-lfftw3</code>. (You
|
|
can link to the different-precision libraries simultaneously.)
|
|
|
|
</li><li> Include the <em>same</em> <code><fftw3.h></code> header file.
|
|
|
|
</li><li> Replace all lowercase instances of ‘<samp>fftw_</samp>’ with ‘<samp>fftwf_</samp>’ or
|
|
‘<samp>fftwl_</samp>’ for single or long-double precision, respectively.
|
|
(<code>fftw_complex</code> becomes <code>fftwf_complex</code>, <code>fftw_execute</code>
|
|
becomes <code>fftwf_execute</code>, etcetera.)
|
|
|
|
</li><li> Uppercase names, i.e. names beginning with ‘<samp>FFTW_</samp>’, remain the
|
|
same.
|
|
|
|
</li><li> Replace <code>double</code> with <code>float</code> or <code>long double</code> for
|
|
subroutine parameters.
|
|
|
|
</li></ul>
|
|
|
|
<p>Depending upon your compiler and/or hardware, <code>long double</code> may not
|
|
be any more precise than <code>double</code> (or may not be supported at all,
|
|
although it is standard in C99).
|
|
<span id="index-C99-2"></span>
|
|
</p>
|
|
|
|
<p>We also support using the nonstandard <code>__float128</code>
|
|
quadruple-precision type provided by recent versions of <code>gcc</code> on
|
|
32- and 64-bit x86 hardware (see <a href="Installation-and-Customization.html">Installation and Customization</a>).
|
|
To use this type, link with <code>-lfftw3q -lquadmath -lm</code> (the
|
|
<code>libquadmath</code> library provided by <code>gcc</code> is needed for
|
|
quadruple-precision trigonometric functions) and use ‘<samp>fftwq_</samp>’
|
|
identifiers.
|
|
</p>
|
|
|
|
|
|
|
|
</body>
|
|
</html>
|