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numpy.fft.ifftshift

numpy.fft.fftshift¶

numpy.fft.fftshift(x, axes=None)[source]

Shift the zero-frequency component to the center of the spectrum.

This function swaps half-spaces for all axes listed (defaults to all). Note that y[0] is the Nyquist component only if len(x) is even.

Parameters: x : array_like Input array. axes : int or shape tuple, optional Axes over which to shift. Default is None, which shifts all axes. y : ndarray The shifted array.

ifftshift
The inverse of fftshift.

Examples

```>>> freqs = np.fft.fftfreq(10, 0.1)
>>> freqs
array([ 0.,  1.,  2.,  3.,  4., -5., -4., -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.]])
```