GitHub - conal/talk-2016-generic-fft: A talk on type-generic FFT in Haskell

The Fast Fourier Transform (FFT) is a fundamentally important algorithm that reduces the cost of the Discrete Fourier Transform (DFT) from $O(n^2)$ to $O(n \log n)$. First discovered by Gauss in 1805, the algorithm was rediscovered and first popularized by Cooley & Tukey only as recently as 1965. This talk presents a simple, parallel-friendly FFT implementation constructed in a type-generic manner

[lotz84]

FFTの計算を関手の合成で記述。出来上がったコードには配列の添字操作もない（安全安心）