Mercurial > hg > sv-dependency-builds
diff src/fftw-3.3.5/doc/html/Precision.html @ 42:2cd0e3b3e1fd
Current fftw source
| author | Chris Cannam |
|---|---|
| date | Tue, 18 Oct 2016 13:40:26 +0100 |
| parents | |
| children |
line wrap: on
line diff
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/fftw-3.3.5/doc/html/Precision.html Tue Oct 18 13:40:26 2016 +0100 @@ -0,0 +1,125 @@ +<!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 3.3.5, 30 July 2016). + +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 5.2, http://www.gnu.org/software/texinfo/ --> +<head> +<title>FFTW 3.3.5: Precision</title> + +<meta name="description" content="FFTW 3.3.5: Precision"> +<meta name="keywords" content="FFTW 3.3.5: Precision"> +<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="Data-Types-and-Files.html#Data-Types-and-Files" rel="up" title="Data Types and Files"> +<link href="Memory-Allocation.html#Memory-Allocation" rel="next" title="Memory Allocation"> +<link href="Complex-numbers.html#Complex-numbers" rel="prev" title="Complex numbers"> +<style type="text/css"> +<!-- +a.summary-letter {text-decoration: none} +blockquote.smallquotation {font-size: smaller} +div.display {margin-left: 3.2em} +div.example {margin-left: 3.2em} +div.indentedblock {margin-left: 3.2em} +div.lisp {margin-left: 3.2em} +div.smalldisplay {margin-left: 3.2em} +div.smallexample {margin-left: 3.2em} +div.smallindentedblock {margin-left: 3.2em; font-size: smaller} +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.nocodebreak {white-space:nowrap} +span.nolinebreak {white-space:nowrap} +span.roman {font-family:serif; font-weight:normal} +span.sansserif {font-family:sans-serif; font-weight:normal} +ul.no-bullet {list-style: none} +--> +</style> + + +</head> + +<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000"> +<a name="Precision"></a> +<div class="header"> +<p> +Next: <a href="Memory-Allocation.html#Memory-Allocation" accesskey="n" rel="next">Memory Allocation</a>, Previous: <a href="Complex-numbers.html#Complex-numbers" accesskey="p" rel="prev">Complex numbers</a>, Up: <a href="Data-Types-and-Files.html#Data-Types-and-Files" 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#Concept-Index" title="Index" rel="index">Index</a>]</p> +</div> +<hr> +<a name="Precision-1"></a> +<h4 class="subsection">4.1.2 Precision</h4> +<a name="index-precision-3"></a> + +<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">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). +<a name="index-C99-2"></a> +</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">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>