[y,range,freq,per] = fft(x)
[y,range,freq,per] = fft(x,range,...)
x [ tseries ] - Input tseries object that will be transformed.
range [ numeric | Inf ] - Date range.
y [ numeric ] - Fourier transform with data organised in columns.
range [ numeric ] - Actually used date range.
freq [ numeric ] - Frequencies corresponding to FFT vector elements.
per [ numeric ] - Periodicities corresponding to FFT vector elements.
'full=' [ true | false ] - Return Fourier transform on the whole interval [0,2*pi]; if false only the interval [0,pi] is returned.}