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author Chris Cannam <cannam@all-day-breakfast.com>
date Wed, 20 Mar 2013 15:35:50 +0000
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3 <title>Interleaved and split arrays - FFTW 3.3.3</title>
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49 <a name="Interleaved-and-split-arrays"></a>
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51 Next:&nbsp;<a rel="next" accesskey="n" href="Guru-vector-and-transform-sizes.html#Guru-vector-and-transform-sizes">Guru vector and transform sizes</a>,
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56
57 <h4 class="subsection">4.5.1 Interleaved and split arrays</h4>
58
59 <p>The guru interface supports two representations of complex numbers,
60 which we call the interleaved and the split format.
61
62 <p>The <dfn>interleaved</dfn> format is the same one used by the basic and
63 advanced interfaces, and it is documented in <a href="Complex-numbers.html#Complex-numbers">Complex numbers</a>.
64 In the interleaved format, you provide pointers to the real part of a
65 complex number, and the imaginary part understood to be stored in the
66 next memory location.
67 <a name="index-interleaved-format-241"></a>
68
69 <p>The <dfn>split</dfn> format allows separate pointers to the real and
70 imaginary parts of a complex array.
71 <a name="index-split-format-242"></a>
72
73 <p>Technically, the interleaved format is redundant, because you can
74 always express an interleaved array in terms of a split array with
75 appropriate pointers and strides. On the other hand, the interleaved
76 format is simpler to use, and it is common in practice. Hence, FFTW
77 supports it as a special case.
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