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Add null config files
author Chris Cannam <cannam@all-day-breakfast.com>
date Mon, 02 Mar 2020 14:03:47 +0000
parents 7867fa7e1b6b
children
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cannam@127 1 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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cannam@127 3 <!-- This manual is for FFTW
cannam@127 4 (version 3.3.5, 30 July 2016).
cannam@127 5
cannam@127 6 Copyright (C) 2003 Matteo Frigo.
cannam@127 7
cannam@127 8 Copyright (C) 2003 Massachusetts Institute of Technology.
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cannam@127 24 <head>
cannam@127 25 <title>FFTW 3.3.5: Guru Real-data DFTs</title>
cannam@127 26
cannam@127 27 <meta name="description" content="FFTW 3.3.5: Guru Real-data DFTs">
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cannam@127 35 <link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
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cannam@127 37 <link href="Guru-Real_002dto_002dreal-Transforms.html#Guru-Real_002dto_002dreal-Transforms" rel="next" title="Guru Real-to-real Transforms">
cannam@127 38 <link href="Guru-Complex-DFTs.html#Guru-Complex-DFTs" rel="prev" title="Guru Complex DFTs">
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cannam@127 69 </head>
cannam@127 70
cannam@127 71 <body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000">
cannam@127 72 <a name="Guru-Real_002ddata-DFTs"></a>
cannam@127 73 <div class="header">
cannam@127 74 <p>
cannam@127 75 Next: <a href="Guru-Real_002dto_002dreal-Transforms.html#Guru-Real_002dto_002dreal-Transforms" accesskey="n" rel="next">Guru Real-to-real Transforms</a>, Previous: <a href="Guru-Complex-DFTs.html#Guru-Complex-DFTs" accesskey="p" rel="prev">Guru Complex DFTs</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@127 76 </div>
cannam@127 77 <hr>
cannam@127 78 <a name="Guru-Real_002ddata-DFTs-1"></a>
cannam@127 79 <h4 class="subsection">4.5.4 Guru Real-data DFTs</h4>
cannam@127 80
cannam@127 81 <div class="example">
cannam@127 82 <pre class="example">fftw_plan fftw_plan_guru_dft_r2c(
cannam@127 83 int rank, const fftw_iodim *dims,
cannam@127 84 int howmany_rank, const fftw_iodim *howmany_dims,
cannam@127 85 double *in, fftw_complex *out,
cannam@127 86 unsigned flags);
cannam@127 87
cannam@127 88 fftw_plan fftw_plan_guru_split_dft_r2c(
cannam@127 89 int rank, const fftw_iodim *dims,
cannam@127 90 int howmany_rank, const fftw_iodim *howmany_dims,
cannam@127 91 double *in, double *ro, double *io,
cannam@127 92 unsigned flags);
cannam@127 93
cannam@127 94 fftw_plan fftw_plan_guru_dft_c2r(
cannam@127 95 int rank, const fftw_iodim *dims,
cannam@127 96 int howmany_rank, const fftw_iodim *howmany_dims,
cannam@127 97 fftw_complex *in, double *out,
cannam@127 98 unsigned flags);
cannam@127 99
cannam@127 100 fftw_plan fftw_plan_guru_split_dft_c2r(
cannam@127 101 int rank, const fftw_iodim *dims,
cannam@127 102 int howmany_rank, const fftw_iodim *howmany_dims,
cannam@127 103 double *ri, double *ii, double *out,
cannam@127 104 unsigned flags);
cannam@127 105 </pre></div>
cannam@127 106 <a name="index-fftw_005fplan_005fguru_005fdft_005fr2c"></a>
cannam@127 107 <a name="index-fftw_005fplan_005fguru_005fsplit_005fdft_005fr2c"></a>
cannam@127 108 <a name="index-fftw_005fplan_005fguru_005fdft_005fc2r"></a>
cannam@127 109 <a name="index-fftw_005fplan_005fguru_005fsplit_005fdft_005fc2r"></a>
cannam@127 110
cannam@127 111 <p>Plan a real-input (r2c) or real-output (c2r), multi-dimensional DFT with
cannam@127 112 transform dimensions given by (<code>rank</code>, <code>dims</code>) over a
cannam@127 113 multi-dimensional vector (loop) of dimensions (<code>howmany_rank</code>,
cannam@127 114 <code>howmany_dims</code>). <code>dims</code> and <code>howmany_dims</code> should point
cannam@127 115 to <code>fftw_iodim</code> arrays of length <code>rank</code> and
cannam@127 116 <code>howmany_rank</code>, respectively. As for the basic and advanced
cannam@127 117 interfaces, an r2c transform is <code>FFTW_FORWARD</code> and a c2r transform
cannam@127 118 is <code>FFTW_BACKWARD</code>.
cannam@127 119 </p>
cannam@127 120 <p>The <em>last</em> dimension of <code>dims</code> is interpreted specially:
cannam@127 121 that dimension of the real array has size <code>dims[rank-1].n</code>, but
cannam@127 122 that dimension of the complex array has size <code>dims[rank-1].n/2+1</code>
cannam@127 123 (division rounded down). The strides, on the other hand, are taken to
cannam@127 124 be exactly as specified. It is up to the user to specify the strides
cannam@127 125 appropriately for the peculiar dimensions of the data, and we do not
cannam@127 126 guarantee that the planner will succeed (return non-<code>NULL</code>) for
cannam@127 127 any dimensions other than those described in <a href="Real_002ddata-DFT-Array-Format.html#Real_002ddata-DFT-Array-Format">Real-data DFT Array Format</a> and generalized in <a href="Advanced-Real_002ddata-DFTs.html#Advanced-Real_002ddata-DFTs">Advanced Real-data DFTs</a>. (That is,
cannam@127 128 for an in-place transform, each individual dimension should be able to
cannam@127 129 operate in place.)
cannam@127 130 <a name="index-in_002dplace-6"></a>
cannam@127 131 </p>
cannam@127 132
cannam@127 133 <p><code>in</code> and <code>out</code> point to the input and output arrays for r2c
cannam@127 134 and c2r transforms, respectively. For split arrays, <code>ri</code> and
cannam@127 135 <code>ii</code> point to the real and imaginary input arrays for a c2r
cannam@127 136 transform, and <code>ro</code> and <code>io</code> point to the real and imaginary
cannam@127 137 output arrays for an r2c transform. <code>in</code> and <code>ro</code> or
cannam@127 138 <code>ri</code> and <code>out</code> may be the same, indicating an in-place
cannam@127 139 transform. (In-place transforms where <code>in</code> and <code>io</code> or
cannam@127 140 <code>ii</code> and <code>out</code> are the same are not currently supported.)
cannam@127 141 </p>
cannam@127 142 <a name="index-flags-6"></a>
cannam@127 143 <p><code>flags</code> is a bitwise OR (&lsquo;<samp>|</samp>&rsquo;) of zero or more planner flags,
cannam@127 144 as defined in <a href="Planner-Flags.html#Planner-Flags">Planner Flags</a>.
cannam@127 145 </p>
cannam@127 146 <p>In-place transforms of rank greater than 1 are currently only
cannam@127 147 supported for interleaved arrays. For split arrays, the planner will
cannam@127 148 return <code>NULL</code>.
cannam@127 149 <a name="index-in_002dplace-7"></a>
cannam@127 150 </p>
cannam@127 151 <hr>
cannam@127 152 <div class="header">
cannam@127 153 <p>
cannam@127 154 Next: <a href="Guru-Real_002dto_002dreal-Transforms.html#Guru-Real_002dto_002dreal-Transforms" accesskey="n" rel="next">Guru Real-to-real Transforms</a>, Previous: <a href="Guru-Complex-DFTs.html#Guru-Complex-DFTs" accesskey="p" rel="prev">Guru Complex DFTs</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@127 155 </div>
cannam@127 156
cannam@127 157
cannam@127 158
cannam@127 159 </body>
cannam@127 160 </html>