fftfreq

powerbox.dft.fftfreq(N, d=1.0, b=6.283185307179586)

Return the fourier frequencies for a box with N cells, using general Fourier convention.

Parameters:

N : int

The number of grid cells

d : float, optional

The interval between cells

b : float, optional

The fourier-convention of the frequency component (see powerbox.dft for details).

Returns:

freq : array

The N symmetric frequency components of the Fourier transform. Always centred at 0.