mirror of
https://github.com/tildearrow/furnace.git
synced 2024-11-16 09:45:06 +00:00
103 lines
4.8 KiB
HTML
103 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>Extended and quadruple precision in Fortran (FFTW 3.3.10)</title>
|
||
|
|
|
||
|
|
<meta name="description" content="Extended and quadruple precision in Fortran (FFTW 3.3.10)">
|
||
|
|
<meta name="keywords" content="Extended and quadruple precision in Fortran (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="Overview-of-Fortran-interface.html" rel="up" title="Overview of Fortran interface">
|
||
|
|
<link href="Reversing-array-dimensions.html" rel="next" title="Reversing array dimensions">
|
||
|
|
<link href="Overview-of-Fortran-interface.html" rel="prev" title="Overview of Fortran interface">
|
||
|
|
<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="Extended-and-quadruple-precision-in-Fortran"></span><div class="header">
|
||
|
|
<p>
|
||
|
|
Previous: <a href="Overview-of-Fortran-interface.html" accesskey="p" rel="prev">Overview of Fortran interface</a>, Up: <a href="Overview-of-Fortran-interface.html" accesskey="u" rel="up">Overview of Fortran interface</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="Extended-and-quadruple-precision-in-Fortran-1"></span><h4 class="subsection">7.1.1 Extended and quadruple precision in Fortran</h4>
|
||
|
|
<span id="index-precision-7"></span>
|
||
|
|
|
||
|
|
<p>If FFTW is compiled in <code>long double</code> (extended) precision
|
||
|
|
(see <a href="Installation-and-Customization.html">Installation and Customization</a>), you may be able to call the
|
||
|
|
resulting <code>fftwl_</code> routines (see <a href="Precision.html">Precision</a>) from Fortran if
|
||
|
|
your compiler supports the <code>C_LONG_DOUBLE_COMPLEX</code> type code.
|
||
|
|
</p>
|
||
|
|
<p>Because some Fortran compilers do not support
|
||
|
|
<code>C_LONG_DOUBLE_COMPLEX</code>, the <code>fftwl_</code> declarations are
|
||
|
|
segregated into a separate interface file <code>fftw3l.f03</code>, which you
|
||
|
|
should include <em>in addition</em> to <code>fftw3.f03</code> (which declares
|
||
|
|
precision-independent ‘<samp>FFTW_</samp>’ constants):
|
||
|
|
</p>
|
||
|
|
<span id="index-iso_005fc_005fbinding-2"></span>
|
||
|
|
<div class="example">
|
||
|
|
<pre class="example"> use, intrinsic :: iso_c_binding
|
||
|
|
include 'fftw3.f03'
|
||
|
|
include 'fftw3l.f03'
|
||
|
|
</pre></div>
|
||
|
|
|
||
|
|
<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>),
|
||
|
|
using the corresponding <code>real(16)</code> and <code>complex(16)</code> types
|
||
|
|
supported by <code>gfortran</code>. The quadruple-precision ‘<samp>fftwq_</samp>’
|
||
|
|
functions (see <a href="Precision.html">Precision</a>) are declared in a <code>fftw3q.f03</code>
|
||
|
|
interface file, which should be included in addition to
|
||
|
|
<code>fftw3.f03</code>, as above. You should also link with
|
||
|
|
<code>-lfftw3q -lquadmath -lm</code> as in C.
|
||
|
|
</p>
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
</body>
|
||
|
|
</html>
|