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diff src/fftw-3.3.5/doc/html/64_002dbit-Guru-Interface.html @ 42:2cd0e3b3e1fd
Current fftw source
| author | Chris Cannam |
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| date | Tue, 18 Oct 2016 13:40:26 +0100 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/fftw-3.3.5/doc/html/64_002dbit-Guru-Interface.html Tue Oct 18 13:40:26 2016 +0100 @@ -0,0 +1,148 @@ +<!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: 64-bit Guru Interface</title> + +<meta name="description" content="FFTW 3.3.5: 64-bit Guru Interface"> +<meta name="keywords" content="FFTW 3.3.5: 64-bit Guru Interface"> +<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="Guru-Interface.html#Guru-Interface" rel="up" title="Guru Interface"> +<link href="New_002darray-Execute-Functions.html#New_002darray-Execute-Functions" rel="next" title="New-array Execute Functions"> +<link href="Guru-Real_002dto_002dreal-Transforms.html#Guru-Real_002dto_002dreal-Transforms" rel="prev" title="Guru Real-to-real Transforms"> +<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="g_t64_002dbit-Guru-Interface"></a> +<div class="header"> +<p> +Previous: <a href="Guru-Real_002dto_002dreal-Transforms.html#Guru-Real_002dto_002dreal-Transforms" accesskey="p" rel="prev">Guru Real-to-real Transforms</a>, Up: <a href="Guru-Interface.html#Guru-Interface" accesskey="u" rel="up">Guru 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="g_t64_002dbit-Guru-Interface-1"></a> +<h4 class="subsection">4.5.6 64-bit Guru Interface</h4> +<a name="index-64_002dbit-architecture"></a> + +<p>When compiled in 64-bit mode on a 64-bit architecture (where addresses +are 64 bits wide), FFTW uses 64-bit quantities internally for all +transform sizes, strides, and so on—you don’t have to do anything +special to exploit this. However, in the ordinary FFTW interfaces, +you specify the transform size by an <code>int</code> quantity, which is +normally only 32 bits wide. This means that, even though FFTW is +using 64-bit sizes internally, you cannot specify a single transform +dimension larger than +2<sup><small>31</small></sup>−1numbers. +</p> +<p>We expect that few users will require transforms larger than this, but, +for those who do, we provide a 64-bit version of the guru interface in +which all sizes are specified as integers of type <code>ptrdiff_t</code> +instead of <code>int</code>. (<code>ptrdiff_t</code> is a signed integer type +defined by the C standard to be wide enough to represent address +differences, and thus must be at least 64 bits wide on a 64-bit +machine.) We stress that there is <em>no performance advantage</em> to +using this interface—the same internal FFTW code is employed +regardless—and it is only necessary if you want to specify very +large transform sizes. +<a name="index-ptrdiff_005ft"></a> +</p> + +<p>In particular, the 64-bit guru interface is a set of planner routines +that are exactly the same as the guru planner routines, except that +they are named with ‘<samp>guru64</samp>’ instead of ‘<samp>guru</samp>’ and they take +arguments of type <code>fftw_iodim64</code> instead of <code>fftw_iodim</code>. +For example, instead of <code>fftw_plan_guru_dft</code>, we have +<code>fftw_plan_guru64_dft</code>. +</p> +<div class="example"> +<pre class="example">fftw_plan fftw_plan_guru64_dft( + int rank, const fftw_iodim64 *dims, + int howmany_rank, const fftw_iodim64 *howmany_dims, + fftw_complex *in, fftw_complex *out, + int sign, unsigned flags); +</pre></div> +<a name="index-fftw_005fplan_005fguru64_005fdft"></a> + +<p>The <code>fftw_iodim64</code> type is similar to <code>fftw_iodim</code>, with the +same interpretation, except that it uses type <code>ptrdiff_t</code> instead +of type <code>int</code>. +</p> +<div class="example"> +<pre class="example">typedef struct { + ptrdiff_t n; + ptrdiff_t is; + ptrdiff_t os; +} fftw_iodim64; +</pre></div> +<a name="index-fftw_005fiodim64"></a> + +<p>Every other ‘<samp>fftw_plan_guru</samp>’ function also has a +‘<samp>fftw_plan_guru64</samp>’ equivalent, but we do not repeat their +documentation here since they are identical to the 32-bit versions +except as noted above. +</p> +<hr> +<div class="header"> +<p> +Previous: <a href="Guru-Real_002dto_002dreal-Transforms.html#Guru-Real_002dto_002dreal-Transforms" accesskey="p" rel="prev">Guru Real-to-real Transforms</a>, Up: <a href="Guru-Interface.html#Guru-Interface" accesskey="u" rel="up">Guru 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> + + + +</body> +</html>