|
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: Interleaved and split arrays</title>
|
|
cannam@167
|
26
|
|
cannam@167
|
27 <meta name="description" content="FFTW 3.3.8: Interleaved and split arrays">
|
|
cannam@167
|
28 <meta name="keywords" content="FFTW 3.3.8: Interleaved and split arrays">
|
|
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="Guru-vector-and-transform-sizes.html#Guru-vector-and-transform-sizes" rel="next" title="Guru vector and transform sizes">
|
|
cannam@167
|
38 <link href="Guru-Interface.html#Guru-Interface" rel="prev" title="Guru Interface">
|
|
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="Interleaved-and-split-arrays"></a>
|
|
cannam@167
|
72 <div class="header">
|
|
cannam@167
|
73 <p>
|
|
cannam@167
|
74 Next: <a href="Guru-vector-and-transform-sizes.html#Guru-vector-and-transform-sizes" accesskey="n" rel="next">Guru vector and transform sizes</a>, Previous: <a href="Guru-Interface.html#Guru-Interface" accesskey="p" rel="prev">Guru Interface</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>
|
|
cannam@167
|
75 </div>
|
|
cannam@167
|
76 <hr>
|
|
cannam@167
|
77 <a name="Interleaved-and-split-arrays-1"></a>
|
|
cannam@167
|
78 <h4 class="subsection">4.5.1 Interleaved and split arrays</h4>
|
|
cannam@167
|
79
|
|
cannam@167
|
80 <p>The guru interface supports two representations of complex numbers,
|
|
cannam@167
|
81 which we call the interleaved and the split format.
|
|
cannam@167
|
82 </p>
|
|
cannam@167
|
83 <p>The <em>interleaved</em> format is the same one used by the basic and
|
|
cannam@167
|
84 advanced interfaces, and it is documented in <a href="Complex-numbers.html#Complex-numbers">Complex numbers</a>.
|
|
cannam@167
|
85 In the interleaved format, you provide pointers to the real part of a
|
|
cannam@167
|
86 complex number, and the imaginary part understood to be stored in the
|
|
cannam@167
|
87 next memory location.
|
|
cannam@167
|
88 <a name="index-interleaved-format"></a>
|
|
cannam@167
|
89 </p>
|
|
cannam@167
|
90
|
|
cannam@167
|
91 <p>The <em>split</em> format allows separate pointers to the real and
|
|
cannam@167
|
92 imaginary parts of a complex array.
|
|
cannam@167
|
93 <a name="index-split-format"></a>
|
|
cannam@167
|
94 </p>
|
|
cannam@167
|
95
|
|
cannam@167
|
96 <p>Technically, the interleaved format is redundant, because you can
|
|
cannam@167
|
97 always express an interleaved array in terms of a split array with
|
|
cannam@167
|
98 appropriate pointers and strides. On the other hand, the interleaved
|
|
cannam@167
|
99 format is simpler to use, and it is common in practice. Hence, FFTW
|
|
cannam@167
|
100 supports it as a special case.
|
|
cannam@167
|
101 </p>
|
|
cannam@167
|
102
|
|
cannam@167
|
103
|
|
cannam@167
|
104
|
|
cannam@167
|
105 </body>
|
|
cannam@167
|
106 </html>
|
