PlasmaCalcs.tools.fft_tools.array_fft.fft2

PlasmaCalcs.tools.fft_tools.array_fft.fft2(array, dx, dy, axes=(-2, -1), *, rad=False, **kw_np_fftn)

calculates fft along 2 dimensions, as well as the corresponding frequencies.

Equivalent to:

fftN(array, (dx, dy), axes=axes, rad=rad, **kw_np_fftn).

array: array-like

take the fft of this array.

dx, dy: numbers

spacing between elements of array (in position-space), along each axis.

This is necessary in order to provide the frequency coordinates for the result.

axes: iterable of ints, default (-2,-1)

axes to take fft over. (Negative values are supported & count from end.)

rad: bool

if True, convert frequencies to “radians” by multiplying them by 2 * pi.

E.g., for fft in space, rad=False gives 1/wavelength; rad=True gives wavenumber k.

additional kwargs passed to np.fft.fftn.

returns (shifted fft2(array, axes=axes, **kw_np_fftn), (freqx, freqy)),

where freqx, freqy are the frequencies corresponding to the x and y axes,

and all freqs & values are shifted with np.fft.fftshift to put the 0-frequency in the center.