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diff src/fftw-3.3.3/doc/html/Extended-and-quadruple-precision-in-Fortran.html @ 95:89f5e221ed7b
Add FFTW3
| author | Chris Cannam <cannam@all-day-breakfast.com> |
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| date | Wed, 20 Mar 2013 15:35:50 +0000 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/fftw-3.3.3/doc/html/Extended-and-quadruple-precision-in-Fortran.html Wed Mar 20 15:35:50 2013 +0000 @@ -0,0 +1,86 @@ +<html lang="en"> +<head> +<title>Extended and quadruple precision in Fortran - FFTW 3.3.3</title> +<meta http-equiv="Content-Type" content="text/html"> +<meta name="description" content="FFTW 3.3.3"> +<meta name="generator" content="makeinfo 4.13"> +<link title="Top" rel="start" href="index.html#Top"> +<link rel="up" href="Overview-of-Fortran-interface.html#Overview-of-Fortran-interface" title="Overview of Fortran interface"> +<link rel="prev" href="Overview-of-Fortran-interface.html#Overview-of-Fortran-interface" title="Overview of Fortran interface"> +<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> +<!-- +This manual is for FFTW +(version 3.3.3, 25 November 2012). + +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. + --> +<meta http-equiv="Content-Style-Type" content="text/css"> +<style type="text/css"><!-- + pre.display { font-family:inherit } + pre.format { font-family:inherit } + pre.smalldisplay { font-family:inherit; font-size:smaller } + pre.smallformat { font-family:inherit; font-size:smaller } + pre.smallexample { font-size:smaller } + pre.smalllisp { font-size:smaller } + span.sc { font-variant:small-caps } + span.roman { font-family:serif; font-weight:normal; } + span.sansserif { font-family:sans-serif; font-weight:normal; } +--></style> +</head> +<body> +<div class="node"> +<a name="Extended-and-quadruple-precision-in-Fortran"></a> +<p> +Previous: <a rel="previous" accesskey="p" href="Overview-of-Fortran-interface.html#Overview-of-Fortran-interface">Overview of Fortran interface</a>, +Up: <a rel="up" accesskey="u" href="Overview-of-Fortran-interface.html#Overview-of-Fortran-interface">Overview of Fortran interface</a> +<hr> +</div> + +<h4 class="subsection">7.1.1 Extended and quadruple precision in Fortran</h4> + +<p><a name="index-precision-515"></a> +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>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><span class="samp">FFTW_</span></samp>’ constants): + + <p><a name="index-iso_005fc_005fbinding-516"></a> +<pre class="example"> use, intrinsic :: iso_c_binding + include 'fftw3.f03' + include 'fftw3l.f03' +</pre> + <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><span class="samp">fftwq_</span></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. + +<!-- --> + </body></html> +