dask.array.fft.fftshift
dask.array.fft.fftshift¶
- dask.array.fft.fftshift(x, axes=None)[source]¶
Shift the zero-frequency component to the center of the spectrum.
This docstring was copied from numpy.fft.fftshift.
Some inconsistencies with the Dask version may exist.
This function swaps half-spaces for all axes listed (defaults to all). Note that
y[0]
is the Nyquist component only iflen(x)
is even.- Parameters
- xarray_like
Input array.
- axesint or shape tuple, optional
Axes over which to shift. Default is None, which shifts all axes.
- Returns
- yndarray
The shifted array.
See also
ifftshift
The inverse of fftshift.
Examples
>>> import numpy as np >>> freqs = np.fft.fftfreq(10, 0.1) >>> freqs array([ 0., 1., 2., ..., -3., -2., -1.]) >>> np.fft.fftshift(freqs) array([-5., -4., -3., -2., -1., 0., 1., 2., 3., 4.])
Shift the zero-frequency component only along the second axis:
>>> freqs = np.fft.fftfreq(9, d=1./9).reshape(3, 3) >>> freqs array([[ 0., 1., 2.], [ 3., 4., -4.], [-3., -2., -1.]]) >>> np.fft.fftshift(freqs, axes=(1,)) array([[ 2., 0., 1.], [-4., 3., 4.], [-1., -3., -2.]])