Mercurial > hg > sv-dependency-builds

annotate src/fftw-3.3.8/doc/html/64_002dbit-Guru-Interface.html @ 167:bd3cc4d1df30

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
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
parents
children
rev   line source
cannam@167 1 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
cannam@167 2 <html>
cannam@167 3 <!-- This manual is for FFTW
cannam@167 4 (version 3.3.8, 24 May 2018).
cannam@167 5
cannam@167 6 Copyright (C) 2003 Matteo Frigo.
cannam@167 7
cannam@167 8 Copyright (C) 2003 Massachusetts Institute of Technology.
cannam@167 9
cannam@167 10 Permission is granted to make and distribute verbatim copies of this
cannam@167 11 manual provided the copyright notice and this permission notice are
cannam@167 12 preserved on all copies.
cannam@167 13
cannam@167 14 Permission is granted to copy and distribute modified versions of this
cannam@167 15 manual under the conditions for verbatim copying, provided that the
cannam@167 16 entire resulting derived work is distributed under the terms of a
cannam@167 17 permission notice identical to this one.
cannam@167 18
cannam@167 19 Permission is granted to copy and distribute translations of this manual
cannam@167 20 into another language, under the above conditions for modified versions,
cannam@167 21 except that this permission notice may be stated in a translation
cannam@167 22 approved by the Free Software Foundation. -->
cannam@167 23 <!-- Created by GNU Texinfo 6.3, http://www.gnu.org/software/texinfo/ -->
cannam@167 24 <head>
cannam@167 25 <title>FFTW 3.3.8: 64-bit Guru Interface</title>
cannam@167 26
cannam@167 27 <meta name="description" content="FFTW 3.3.8: 64-bit Guru Interface">
cannam@167 28 <meta name="keywords" content="FFTW 3.3.8: 64-bit Guru Interface">
cannam@167 29 <meta name="resource-type" content="document">
cannam@167 30 <meta name="distribution" content="global">
cannam@167 31 <meta name="Generator" content="makeinfo">
cannam@167 32 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
cannam@167 33 <link href="index.html#Top" rel="start" title="Top">
cannam@167 34 <link href="Concept-Index.html#Concept-Index" rel="index" title="Concept Index">
cannam@167 35 <link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
cannam@167 36 <link href="Guru-Interface.html#Guru-Interface" rel="up" title="Guru Interface">
cannam@167 37 <link href="New_002darray-Execute-Functions.html#New_002darray-Execute-Functions" rel="next" title="New-array Execute Functions">
cannam@167 38 <link href="Guru-Real_002dto_002dreal-Transforms.html#Guru-Real_002dto_002dreal-Transforms" rel="prev" title="Guru Real-to-real Transforms">
cannam@167 39 <style type="text/css">
cannam@167 40 <!--
cannam@167 41 a.summary-letter {text-decoration: none}
cannam@167 42 blockquote.indentedblock {margin-right: 0em}
cannam@167 43 blockquote.smallindentedblock {margin-right: 0em; font-size: smaller}
cannam@167 44 blockquote.smallquotation {font-size: smaller}
cannam@167 45 div.display {margin-left: 3.2em}
cannam@167 46 div.example {margin-left: 3.2em}
cannam@167 47 div.lisp {margin-left: 3.2em}
cannam@167 48 div.smalldisplay {margin-left: 3.2em}
cannam@167 49 div.smallexample {margin-left: 3.2em}
cannam@167 50 div.smalllisp {margin-left: 3.2em}
cannam@167 51 kbd {font-style: oblique}
cannam@167 52 pre.display {font-family: inherit}
cannam@167 53 pre.format {font-family: inherit}
cannam@167 54 pre.menu-comment {font-family: serif}
cannam@167 55 pre.menu-preformatted {font-family: serif}
cannam@167 56 pre.smalldisplay {font-family: inherit; font-size: smaller}
cannam@167 57 pre.smallexample {font-size: smaller}
cannam@167 58 pre.smallformat {font-family: inherit; font-size: smaller}
cannam@167 59 pre.smalllisp {font-size: smaller}
cannam@167 60 span.nolinebreak {white-space: nowrap}
cannam@167 61 span.roman {font-family: initial; font-weight: normal}
cannam@167 62 span.sansserif {font-family: sans-serif; font-weight: normal}
cannam@167 63 ul.no-bullet {list-style: none}
cannam@167 64 -->
cannam@167 65 </style>
cannam@167 66
cannam@167 67
cannam@167 68 </head>
cannam@167 69
cannam@167 70 <body lang="en">
cannam@167 71 <a name="g_t64_002dbit-Guru-Interface"></a>
cannam@167 72 <div class="header">
cannam@167 73 <p>
cannam@167 74 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> &nbsp; [<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>
cannam@167 75 </div>
cannam@167 76 <hr>
cannam@167 77 <a name="g_t64_002dbit-Guru-Interface-1"></a>
cannam@167 78 <h4 class="subsection">4.5.6 64-bit Guru Interface</h4>
cannam@167 79 <a name="index-64_002dbit-architecture"></a>
cannam@167 80
cannam@167 81 <p>When compiled in 64-bit mode on a 64-bit architecture (where addresses
cannam@167 82 are 64 bits wide), FFTW uses 64-bit quantities internally for all
cannam@167 83 transform sizes, strides, and so on&mdash;you don&rsquo;t have to do anything
cannam@167 84 special to exploit this. However, in the ordinary FFTW interfaces,
cannam@167 85 you specify the transform size by an <code>int</code> quantity, which is
cannam@167 86 normally only 32 bits wide. This means that, even though FFTW is
cannam@167 87 using 64-bit sizes internally, you cannot specify a single transform
cannam@167 88 dimension larger than
cannam@167 89 2<sup><small>31</small></sup>&minus;1
cannam@167 90 numbers.
cannam@167 91 </p>
cannam@167 92 <p>We expect that few users will require transforms larger than this, but,
cannam@167 93 for those who do, we provide a 64-bit version of the guru interface in
cannam@167 94 which all sizes are specified as integers of type <code>ptrdiff_t</code>
cannam@167 95 instead of <code>int</code>. (<code>ptrdiff_t</code> is a signed integer type
cannam@167 96 defined by the C standard to be wide enough to represent address
cannam@167 97 differences, and thus must be at least 64 bits wide on a 64-bit
cannam@167 98 machine.) We stress that there is <em>no performance advantage</em> to
cannam@167 99 using this interface&mdash;the same internal FFTW code is employed
cannam@167 100 regardless&mdash;and it is only necessary if you want to specify very
cannam@167 101 large transform sizes.
cannam@167 102 <a name="index-ptrdiff_005ft"></a>
cannam@167 103 </p>
cannam@167 104
cannam@167 105 <p>In particular, the 64-bit guru interface is a set of planner routines
cannam@167 106 that are exactly the same as the guru planner routines, except that
cannam@167 107 they are named with &lsquo;<samp>guru64</samp>&rsquo; instead of &lsquo;<samp>guru</samp>&rsquo; and they take
cannam@167 108 arguments of type <code>fftw_iodim64</code> instead of <code>fftw_iodim</code>.
cannam@167 109 For example, instead of <code>fftw_plan_guru_dft</code>, we have
cannam@167 110 <code>fftw_plan_guru64_dft</code>.
cannam@167 111 </p>
cannam@167 112 <div class="example">
cannam@167 113 <pre class="example">fftw_plan fftw_plan_guru64_dft(
cannam@167 114 int rank, const fftw_iodim64 *dims,
cannam@167 115 int howmany_rank, const fftw_iodim64 *howmany_dims,
cannam@167 116 fftw_complex *in, fftw_complex *out,
cannam@167 117 int sign, unsigned flags);
cannam@167 118 </pre></div>
cannam@167 119 <a name="index-fftw_005fplan_005fguru64_005fdft"></a>
cannam@167 120
cannam@167 121 <p>The <code>fftw_iodim64</code> type is similar to <code>fftw_iodim</code>, with the
cannam@167 122 same interpretation, except that it uses type <code>ptrdiff_t</code> instead
cannam@167 123 of type <code>int</code>.
cannam@167 124 </p>
cannam@167 125 <div class="example">
cannam@167 126 <pre class="example">typedef struct {
cannam@167 127 ptrdiff_t n;
cannam@167 128 ptrdiff_t is;
cannam@167 129 ptrdiff_t os;
cannam@167 130 } fftw_iodim64;
cannam@167 131 </pre></div>
cannam@167 132 <a name="index-fftw_005fiodim64"></a>
cannam@167 133
cannam@167 134 <p>Every other &lsquo;<samp>fftw_plan_guru</samp>&rsquo; function also has a
cannam@167 135 &lsquo;<samp>fftw_plan_guru64</samp>&rsquo; equivalent, but we do not repeat their
cannam@167 136 documentation here since they are identical to the 32-bit versions
cannam@167 137 except as noted above.
cannam@167 138 </p>
cannam@167 139 <hr>
cannam@167 140 <div class="header">
cannam@167 141 <p>
cannam@167 142 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> &nbsp; [<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>
cannam@167 143 </div>
cannam@167 144
cannam@167 145
cannam@167 146
cannam@167 147 </body>
cannam@167 148 </html>