fftw3: 1d Discrete Hartley Transforms (DHTs)
4.8.5 1d Discrete Hartley Transforms (DHTs)
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The discrete Hartley transform (DHT) of a 1d real array X of size n
computes a real array Y of the same size, where:
Y[k] = sum for j = 0 to (n - 1) of X[j] * [cos(2 pi j k / n) + sin(2 pi j k / n)].
FFTW computes an unnormalized transform, in that there is no
coefficient in front of the summation in the DHT. In other words,
applying the transform twice (the DHT is its own inverse) will multiply
the input by n.
Info Catalog
fftw3: 1d Real-odd DFTs (DSTs)
fftw3: What FFTW Really Computes
fftw3: Multi-dimensional Transforms