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Current fftw source
author Chris Cannam
date Tue, 18 Oct 2016 13:40:26 +0100
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Chris@42 25 <title>FFTW 3.3.5: Interleaved and split arrays</title>
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Chris@42 71 <body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000">
Chris@42 72 <a name="Interleaved-and-split-arrays"></a>
Chris@42 73 <div class="header">
Chris@42 74 <p>
Chris@42 75 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> &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@42 76 </div>
Chris@42 77 <hr>
Chris@42 78 <a name="Interleaved-and-split-arrays-1"></a>
Chris@42 79 <h4 class="subsection">4.5.1 Interleaved and split arrays</h4>
Chris@42 80
Chris@42 81 <p>The guru interface supports two representations of complex numbers,
Chris@42 82 which we call the interleaved and the split format.
Chris@42 83 </p>
Chris@42 84 <p>The <em>interleaved</em> format is the same one used by the basic and
Chris@42 85 advanced interfaces, and it is documented in <a href="Complex-numbers.html#Complex-numbers">Complex numbers</a>.
Chris@42 86 In the interleaved format, you provide pointers to the real part of a
Chris@42 87 complex number, and the imaginary part understood to be stored in the
Chris@42 88 next memory location.
Chris@42 89 <a name="index-interleaved-format"></a>
Chris@42 90 </p>
Chris@42 91
Chris@42 92 <p>The <em>split</em> format allows separate pointers to the real and
Chris@42 93 imaginary parts of a complex array.
Chris@42 94 <a name="index-split-format"></a>
Chris@42 95 </p>
Chris@42 96
Chris@42 97 <p>Technically, the interleaved format is redundant, because you can
Chris@42 98 always express an interleaved array in terms of a split array with
Chris@42 99 appropriate pointers and strides. On the other hand, the interleaved
Chris@42 100 format is simpler to use, and it is common in practice. Hence, FFTW
Chris@42 101 supports it as a special case.
Chris@42 102 </p>
Chris@42 103
Chris@42 104
Chris@42 105
Chris@42 106 </body>
Chris@42 107 </html>