fftw: fftw (Fastest Fourier Transform in the West)
fftw: 
fftw: is a free collection libraries for computing the (DFT) Fourier
fftw: Transform in one or more dimensions. It includes complex, real,
fftw: symmetric, and parallel transforms, and can handle arbitrary array
fftw: sizes efficiently.
fftw: 
fftw: http://www.fftw.org/
fftw: 
fftw: 
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