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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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25 <title>FFTW 3.3.8: Interleaved and split arrays</title>
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71 <a name="Interleaved-and-split-arrays"></a>
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73 <p>
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> &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>
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76 <hr>
77 <a name="Interleaved-and-split-arrays-1"></a>
78 <h4 class="subsection">4.5.1 Interleaved and split arrays</h4>
79
80 <p>The guru interface supports two representations of complex numbers,
81 which we call the interleaved and the split format.
82 </p>
83 <p>The <em>interleaved</em> format is the same one used by the basic and
84 advanced interfaces, and it is documented in <a href="Complex-numbers.html#Complex-numbers">Complex numbers</a>.
85 In the interleaved format, you provide pointers to the real part of a
86 complex number, and the imaginary part understood to be stored in the
87 next memory location.
88 <a name="index-interleaved-format"></a>
89 </p>
90
91 <p>The <em>split</em> format allows separate pointers to the real and
92 imaginary parts of a complex array.
93 <a name="index-split-format"></a>
94 </p>
95
96 <p>Technically, the interleaved format is redundant, because you can
97 always express an interleaved array in terms of a split array with
98 appropriate pointers and strides. On the other hand, the interleaved
99 format is simpler to use, and it is common in practice. Hence, FFTW
100 supports it as a special case.
101 </p>
102
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