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Add FFTW 3.3.8 source, and a Linux build
author Chris Cannam
date Tue, 19 Nov 2019 14:52:55 +0000
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Chris@82 1 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
Chris@82 2 <html>
Chris@82 3 <!-- This manual is for FFTW
Chris@82 4 (version 3.3.8, 24 May 2018).
Chris@82 5
Chris@82 6 Copyright (C) 2003 Matteo Frigo.
Chris@82 7
Chris@82 8 Copyright (C) 2003 Massachusetts Institute of Technology.
Chris@82 9
Chris@82 10 Permission is granted to make and distribute verbatim copies of this
Chris@82 11 manual provided the copyright notice and this permission notice are
Chris@82 12 preserved on all copies.
Chris@82 13
Chris@82 14 Permission is granted to copy and distribute modified versions of this
Chris@82 15 manual under the conditions for verbatim copying, provided that the
Chris@82 16 entire resulting derived work is distributed under the terms of a
Chris@82 17 permission notice identical to this one.
Chris@82 18
Chris@82 19 Permission is granted to copy and distribute translations of this manual
Chris@82 20 into another language, under the above conditions for modified versions,
Chris@82 21 except that this permission notice may be stated in a translation
Chris@82 22 approved by the Free Software Foundation. -->
Chris@82 23 <!-- Created by GNU Texinfo 6.3, http://www.gnu.org/software/texinfo/ -->
Chris@82 24 <head>
Chris@82 25 <title>FFTW 3.3.8: 64-bit Guru Interface</title>
Chris@82 26
Chris@82 27 <meta name="description" content="FFTW 3.3.8: 64-bit Guru Interface">
Chris@82 28 <meta name="keywords" content="FFTW 3.3.8: 64-bit Guru Interface">
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Chris@82 34 <link href="Concept-Index.html#Concept-Index" rel="index" title="Concept Index">
Chris@82 35 <link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
Chris@82 36 <link href="Guru-Interface.html#Guru-Interface" rel="up" title="Guru Interface">
Chris@82 37 <link href="New_002darray-Execute-Functions.html#New_002darray-Execute-Functions" rel="next" title="New-array Execute Functions">
Chris@82 38 <link href="Guru-Real_002dto_002dreal-Transforms.html#Guru-Real_002dto_002dreal-Transforms" rel="prev" title="Guru Real-to-real Transforms">
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Chris@82 66
Chris@82 67
Chris@82 68 </head>
Chris@82 69
Chris@82 70 <body lang="en">
Chris@82 71 <a name="g_t64_002dbit-Guru-Interface"></a>
Chris@82 72 <div class="header">
Chris@82 73 <p>
Chris@82 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>
Chris@82 75 </div>
Chris@82 76 <hr>
Chris@82 77 <a name="g_t64_002dbit-Guru-Interface-1"></a>
Chris@82 78 <h4 class="subsection">4.5.6 64-bit Guru Interface</h4>
Chris@82 79 <a name="index-64_002dbit-architecture"></a>
Chris@82 80
Chris@82 81 <p>When compiled in 64-bit mode on a 64-bit architecture (where addresses
Chris@82 82 are 64 bits wide), FFTW uses 64-bit quantities internally for all
Chris@82 83 transform sizes, strides, and so on&mdash;you don&rsquo;t have to do anything
Chris@82 84 special to exploit this. However, in the ordinary FFTW interfaces,
Chris@82 85 you specify the transform size by an <code>int</code> quantity, which is
Chris@82 86 normally only 32 bits wide. This means that, even though FFTW is
Chris@82 87 using 64-bit sizes internally, you cannot specify a single transform
Chris@82 88 dimension larger than
Chris@82 89 2<sup><small>31</small></sup>&minus;1
Chris@82 90 numbers.
Chris@82 91 </p>
Chris@82 92 <p>We expect that few users will require transforms larger than this, but,
Chris@82 93 for those who do, we provide a 64-bit version of the guru interface in
Chris@82 94 which all sizes are specified as integers of type <code>ptrdiff_t</code>
Chris@82 95 instead of <code>int</code>. (<code>ptrdiff_t</code> is a signed integer type
Chris@82 96 defined by the C standard to be wide enough to represent address
Chris@82 97 differences, and thus must be at least 64 bits wide on a 64-bit
Chris@82 98 machine.) We stress that there is <em>no performance advantage</em> to
Chris@82 99 using this interface&mdash;the same internal FFTW code is employed
Chris@82 100 regardless&mdash;and it is only necessary if you want to specify very
Chris@82 101 large transform sizes.
Chris@82 102 <a name="index-ptrdiff_005ft"></a>
Chris@82 103 </p>
Chris@82 104
Chris@82 105 <p>In particular, the 64-bit guru interface is a set of planner routines
Chris@82 106 that are exactly the same as the guru planner routines, except that
Chris@82 107 they are named with &lsquo;<samp>guru64</samp>&rsquo; instead of &lsquo;<samp>guru</samp>&rsquo; and they take
Chris@82 108 arguments of type <code>fftw_iodim64</code> instead of <code>fftw_iodim</code>.
Chris@82 109 For example, instead of <code>fftw_plan_guru_dft</code>, we have
Chris@82 110 <code>fftw_plan_guru64_dft</code>.
Chris@82 111 </p>
Chris@82 112 <div class="example">
Chris@82 113 <pre class="example">fftw_plan fftw_plan_guru64_dft(
Chris@82 114 int rank, const fftw_iodim64 *dims,
Chris@82 115 int howmany_rank, const fftw_iodim64 *howmany_dims,
Chris@82 116 fftw_complex *in, fftw_complex *out,
Chris@82 117 int sign, unsigned flags);
Chris@82 118 </pre></div>
Chris@82 119 <a name="index-fftw_005fplan_005fguru64_005fdft"></a>
Chris@82 120
Chris@82 121 <p>The <code>fftw_iodim64</code> type is similar to <code>fftw_iodim</code>, with the
Chris@82 122 same interpretation, except that it uses type <code>ptrdiff_t</code> instead
Chris@82 123 of type <code>int</code>.
Chris@82 124 </p>
Chris@82 125 <div class="example">
Chris@82 126 <pre class="example">typedef struct {
Chris@82 127 ptrdiff_t n;
Chris@82 128 ptrdiff_t is;
Chris@82 129 ptrdiff_t os;
Chris@82 130 } fftw_iodim64;
Chris@82 131 </pre></div>
Chris@82 132 <a name="index-fftw_005fiodim64"></a>
Chris@82 133
Chris@82 134 <p>Every other &lsquo;<samp>fftw_plan_guru</samp>&rsquo; function also has a
Chris@82 135 &lsquo;<samp>fftw_plan_guru64</samp>&rsquo; equivalent, but we do not repeat their
Chris@82 136 documentation here since they are identical to the 32-bit versions
Chris@82 137 except as noted above.
Chris@82 138 </p>
Chris@82 139 <hr>
Chris@82 140 <div class="header">
Chris@82 141 <p>
Chris@82 142 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>
Chris@82 143 </div>
Chris@82 144
Chris@82 145
Chris@82 146
Chris@82 147 </body>
Chris@82 148 </html>