Mercurial > hg > sv-dependency-builds
diff src/fftw-3.3.8/doc/html/Extended-and-quadruple-precision-in-Fortran.html @ 167:bd3cc4d1df30
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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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/fftw-3.3.8/doc/html/Extended-and-quadruple-precision-in-Fortran.html Tue Nov 19 14:52:55 2019 +0000 @@ -0,0 +1,113 @@ +<!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 3.3.8, 24 May 2018). + +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 6.3, http://www.gnu.org/software/texinfo/ --> +<head> +<title>FFTW 3.3.8: Extended and quadruple precision in Fortran</title> + +<meta name="description" content="FFTW 3.3.8: Extended and quadruple precision in Fortran"> +<meta name="keywords" content="FFTW 3.3.8: Extended and quadruple precision in Fortran"> +<meta name="resource-type" content="document"> +<meta name="distribution" content="global"> +<meta name="Generator" content="makeinfo"> +<meta http-equiv="Content-Type" content="text/html; charset=utf-8"> +<link href="index.html#Top" rel="start" title="Top"> +<link href="Concept-Index.html#Concept-Index" rel="index" title="Concept Index"> +<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> +<link href="Overview-of-Fortran-interface.html#Overview-of-Fortran-interface" rel="up" title="Overview of Fortran interface"> +<link href="Reversing-array-dimensions.html#Reversing-array-dimensions" rel="next" title="Reversing array dimensions"> +<link href="Overview-of-Fortran-interface.html#Overview-of-Fortran-interface" rel="prev" title="Overview of Fortran interface"> +<style type="text/css"> +<!-- +a.summary-letter {text-decoration: none} +blockquote.indentedblock {margin-right: 0em} +blockquote.smallindentedblock {margin-right: 0em; font-size: smaller} +blockquote.smallquotation {font-size: smaller} +div.display {margin-left: 3.2em} +div.example {margin-left: 3.2em} +div.lisp {margin-left: 3.2em} +div.smalldisplay {margin-left: 3.2em} +div.smallexample {margin-left: 3.2em} +div.smalllisp {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} +pre.smalldisplay {font-family: inherit; font-size: smaller} +pre.smallexample {font-size: smaller} +pre.smallformat {font-family: inherit; font-size: smaller} +pre.smalllisp {font-size: smaller} +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"> +<a name="Extended-and-quadruple-precision-in-Fortran"></a> +<div class="header"> +<p> +Previous: <a href="Overview-of-Fortran-interface.html#Overview-of-Fortran-interface" accesskey="p" rel="prev">Overview of Fortran interface</a>, Up: <a href="Overview-of-Fortran-interface.html#Overview-of-Fortran-interface" 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#Concept-Index" title="Index" rel="index">Index</a>]</p> +</div> +<hr> +<a name="Extended-and-quadruple-precision-in-Fortran-1"></a> +<h4 class="subsection">7.1.1 Extended and quadruple precision in Fortran</h4> +<a name="index-precision-7"></a> + +<p>If FFTW is compiled in <code>long double</code> (extended) precision +(see <a href="Installation-and-Customization.html#Installation-and-Customization">Installation and Customization</a>), you may be able to call the +resulting <code>fftwl_</code> routines (see <a href="Precision.html#Precision">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> +<a name="index-iso_005fc_005fbinding-2"></a> +<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">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">Precision</a>) are declared in a <code>fftw3q.f03</code> +interface file, which should be included in addition to +<code>fftw3l.f03</code>, as above. You should also link with +<code>-lfftw3q -lquadmath -lm</code> as in C. +</p> + + + +</body> +</html>