comparison src/fftw-3.3.8/doc/html/1d-Discrete-Hartley-Transforms-_0028DHTs_0029.html @ 167:bd3cc4d1df30

Add FFTW 3.3.8 source, and a Linux build
author Chris Cannam <cannam@all-day-breakfast.com>
date Tue, 19 Nov 2019 14:52:55 +0000
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77 <a name="g_t1d-Discrete-Hartley-Transforms-_0028DHTs_0029-1"></a>
78 <h4 class="subsection">4.8.5 1d Discrete Hartley Transforms (DHTs)</h4>
79
80 <a name="index-discrete-Hartley-transform-2"></a>
81 <a name="index-DHT-1"></a>
82 <p>The discrete Hartley transform (DHT) of a 1d real array <em>X</em> of size
83 <em>n</em> computes a real array <em>Y</em> of the same size, where:
84 <center><img src="equation-dht.png" align="top">.</center>
85 </p>
86 <a name="index-normalization-12"></a>
87 <p>FFTW computes an unnormalized transform, in that there is no coefficient
88 in front of the summation in the DHT. In other words, applying the
89 transform twice (the DHT is its own inverse) will multiply the input by
90 <em>n</em>.
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