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Current fftw source
author Chris Cannam <cannam@all-day-breakfast.com>
date Tue, 18 Oct 2016 13:40:26 +0100
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72 <a name="Interleaved-and-split-arrays"></a>
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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>
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78 <a name="Interleaved-and-split-arrays-1"></a>
79 <h4 class="subsection">4.5.1 Interleaved and split arrays</h4>
80
81 <p>The guru interface supports two representations of complex numbers,
82 which we call the interleaved and the split format.
83 </p>
84 <p>The <em>interleaved</em> format is the same one used by the basic and
85 advanced interfaces, and it is documented in <a href="Complex-numbers.html#Complex-numbers">Complex numbers</a>.
86 In the interleaved format, you provide pointers to the real part of a
87 complex number, and the imaginary part understood to be stored in the
88 next memory location.
89 <a name="index-interleaved-format"></a>
90 </p>
91
92 <p>The <em>split</em> format allows separate pointers to the real and
93 imaginary parts of a complex array.
94 <a name="index-split-format"></a>
95 </p>
96
97 <p>Technically, the interleaved format is redundant, because you can
98 always express an interleaved array in terms of a split array with
99 appropriate pointers and strides. On the other hand, the interleaved
100 format is simpler to use, and it is common in practice. Hence, FFTW
101 supports it as a special case.
102 </p>
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