Mercurial > hg > batch-feature-extraction-tool

annotate Lib/fftw-3.2.1/doc/html/.svn/text-base/Advanced-Real_002ddata-DFTs.html.svn-base @ 14:636c989477e7

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
XML changes for Public.
author Geogaddi\David <d.m.ronan@qmul.ac.uk>
date Wed, 04 May 2016 11:02:59 +0100
parents 25bf17994ef1
children
rev   line source
d@0 1 <html lang="en">
d@0 2 <head>
d@0 3 <title>Advanced Real-data DFTs - FFTW 3.2.1</title>
d@0 4 <meta http-equiv="Content-Type" content="text/html">
d@0 5 <meta name="description" content="FFTW 3.2.1">
d@0 6 <meta name="generator" content="makeinfo 4.8">
d@0 7 <link title="Top" rel="start" href="index.html#Top">
d@0 8 <link rel="up" href="Advanced-Interface.html#Advanced-Interface" title="Advanced Interface">
d@0 9 <link rel="prev" href="Advanced-Complex-DFTs.html#Advanced-Complex-DFTs" title="Advanced Complex DFTs">
d@0 10 <link rel="next" href="Advanced-Real_002dto_002dreal-Transforms.html#Advanced-Real_002dto_002dreal-Transforms" title="Advanced Real-to-real Transforms">
d@0 11 <link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
d@0 12 <!--
d@0 13 This manual is for FFTW
d@0 14 (version 3.2.1, 5 February 2009).
d@0 15
d@0 16 Copyright (C) 2003 Matteo Frigo.
d@0 17
d@0 18 Copyright (C) 2003 Massachusetts Institute of Technology.
d@0 19
d@0 20 Permission is granted to make and distribute verbatim copies of
d@0 21 this manual provided the copyright notice and this permission
d@0 22 notice are preserved on all copies.
d@0 23
d@0 24 Permission is granted to copy and distribute modified versions of
d@0 25 this manual under the conditions for verbatim copying, provided
d@0 26 that the entire resulting derived work is distributed under the
d@0 27 terms of a permission notice identical to this one.
d@0 28
d@0 29 Permission is granted to copy and distribute translations of this
d@0 30 manual into another language, under the above conditions for
d@0 31 modified versions, except that this permission notice may be
d@0 32 stated in a translation approved by the Free Software Foundation.
d@0 33 -->
d@0 34 <meta http-equiv="Content-Style-Type" content="text/css">
d@0 35 <style type="text/css"><!--
d@0 36 pre.display { font-family:inherit }
d@0 37 pre.format { font-family:inherit }
d@0 38 pre.smalldisplay { font-family:inherit; font-size:smaller }
d@0 39 pre.smallformat { font-family:inherit; font-size:smaller }
d@0 40 pre.smallexample { font-size:smaller }
d@0 41 pre.smalllisp { font-size:smaller }
d@0 42 span.sc { font-variant:small-caps }
d@0 43 span.roman { font-family:serif; font-weight:normal; }
d@0 44 span.sansserif { font-family:sans-serif; font-weight:normal; }
d@0 45 --></style>
d@0 46 </head>
d@0 47 <body>
d@0 48 <div class="node">
d@0 49 <p>
d@0 50 <a name="Advanced-Real-data-DFTs"></a>
d@0 51 <a name="Advanced-Real_002ddata-DFTs"></a>
d@0 52 Next:&nbsp;<a rel="next" accesskey="n" href="Advanced-Real_002dto_002dreal-Transforms.html#Advanced-Real_002dto_002dreal-Transforms">Advanced Real-to-real Transforms</a>,
d@0 53 Previous:&nbsp;<a rel="previous" accesskey="p" href="Advanced-Complex-DFTs.html#Advanced-Complex-DFTs">Advanced Complex DFTs</a>,
d@0 54 Up:&nbsp;<a rel="up" accesskey="u" href="Advanced-Interface.html#Advanced-Interface">Advanced Interface</a>
d@0 55 <hr>
d@0 56 </div>
d@0 57
d@0 58 <h4 class="subsection">4.4.2 Advanced Real-data DFTs</h4>
d@0 59
d@0 60 <pre class="example"> fftw_plan fftw_plan_many_dft_r2c(int rank, const int *n, int howmany,
d@0 61 double *in, const int *inembed,
d@0 62 int istride, int idist,
d@0 63 fftw_complex *out, const int *onembed,
d@0 64 int ostride, int odist,
d@0 65 unsigned flags);
d@0 66 fftw_plan fftw_plan_many_dft_c2r(int rank, const int *n, int howmany,
d@0 67 fftw_complex *in, const int *inembed,
d@0 68 int istride, int idist,
d@0 69 double *out, const int *onembed,
d@0 70 int ostride, int odist,
d@0 71 unsigned flags);
d@0 72 </pre>
d@0 73 <p><a name="index-fftw_005fplan_005fmany_005fdft_005fr2c-228"></a><a name="index-fftw_005fplan_005fmany_005fdft_005fc2r-229"></a>
d@0 74 Like <code>fftw_plan_many_dft</code>, these two functions add <code>howmany</code>,
d@0 75 <code>nembed</code>, <code>stride</code>, and <code>dist</code> parameters to the
d@0 76 <code>fftw_plan_dft_r2c</code> and <code>fftw_plan_dft_c2r</code> functions, but
d@0 77 otherwise behave the same as the basic interface.
d@0 78
d@0 79 <p>The interpretation of <code>howmany</code>, <code>stride</code>, and <code>dist</code> are
d@0 80 the same as for <code>fftw_plan_many_dft</code>, above. Note that the
d@0 81 <code>stride</code> and <code>dist</code> for the real array are in units of
d@0 82 <code>double</code>, and for the complex array are in units of
d@0 83 <code>fftw_complex</code>.
d@0 84
d@0 85 <p>If an <code>nembed</code> parameter is <code>NULL</code>, it is interpreted as what
d@0 86 it would be in the basic interface, as described in <a href="Real_002ddata-DFT-Array-Format.html#Real_002ddata-DFT-Array-Format">Real-data DFT Array Format</a>. That is, for the complex array the size is assumed to be
d@0 87 the same as <code>n</code>, but with the last dimension cut roughly in half.
d@0 88 For the real array, the size is assumed to be <code>n</code> if the transform
d@0 89 is out-of-place, or <code>n</code> with the last dimension &ldquo;padded&rdquo; if the
d@0 90 transform is in-place.
d@0 91
d@0 92 <p>If an <code>nembed</code> parameter is non-<code>NULL</code>, it is interpreted as
d@0 93 the physical size of the corresponding array, in row-major order, just
d@0 94 as for <code>fftw_plan_many_dft</code>. In this case, each dimension of
d@0 95 <code>nembed</code> should be <code>&gt;=</code> what it would be in the basic
d@0 96 interface (e.g. the halved or padded <code>n</code>).
d@0 97
d@0 98 <p>Arrays <code>n</code>, <code>inembed</code>, and <code>onembed</code> are not used after
d@0 99 this function returns. You can safely free or reuse them.
d@0 100
d@0 101 <!-- =========> -->
d@0 102 </body></html>
d@0 103