# scipy.fft.ifft2#

scipy.fft.ifft2(x, s=None, axes=(-2, -1), norm=None, overwrite_x=False, workers=None, *, plan=None)[source]#

Compute the 2-D inverse discrete Fourier Transform.

This function computes the inverse of the 2-D discrete Fourier Transform over any number of axes in an M-D array by means of the Fast Fourier Transform (FFT). In other words, `ifft2(fft2(x)) == x` to within numerical accuracy. By default, the inverse transform is computed over the last two axes of the input array.

The input, analogously to `ifft`, should be ordered in the same way as is returned by `fft2`, i.e., it should have the term for zero frequency in the low-order corner of the two axes, the positive frequency terms in the first half of these axes, the term for the Nyquist frequency in the middle of the axes and the negative frequency terms in the second half of both axes, in order of decreasingly negative frequency.

Parameters:
xarray_like

Input array, can be complex.

ssequence of ints, optional

Shape (length of each axis) of the output (`s[0]` refers to axis 0, `s[1]` to axis 1, etc.). This corresponds to n for `ifft(x, n)`. Along each axis, if the given shape is smaller than that of the input, the input is cropped. If it is larger, the input is padded with zeros. if s is not given, the shape of the input along the axes specified by axes is used. See notes for issue on `ifft` zero padding.

axessequence of ints, optional

Axes over which to compute the FFT. If not given, the last two axes are used.

norm{“backward”, “ortho”, “forward”}, optional

Normalization mode (see `fft`). Default is “backward”.

overwrite_xbool, optional

If True, the contents of x can be destroyed; the default is False. See `fft` for more details.

workersint, optional

Maximum number of workers to use for parallel computation. If negative, the value wraps around from `os.cpu_count()`. See `fft` for more details.

planobject, optional

This argument is reserved for passing in a precomputed plan provided by downstream FFT vendors. It is currently not used in SciPy.

Returns:
outcomplex ndarray

The truncated or zero-padded input, transformed along the axes indicated by axes, or the last two axes if axes is not given.

Raises:
ValueError

If s and axes have different length, or axes not given and `len(s) != 2`.

IndexError

If an element of axes is larger than the number of axes of x.

`fft2`

The forward 2-D FFT, of which `ifft2` is the inverse.

`ifftn`

The inverse of the N-D FFT.

`fft`

The 1-D FFT.

`ifft`

The 1-D inverse FFT.

Notes

`ifft2` is just `ifftn` with a different default for axes.

See `ifftn` for details and a plotting example, and `fft` for definition and conventions used.

Zero-padding, analogously with `ifft`, is performed by appending zeros to the input along the specified dimension. Although this is the common approach, it might lead to surprising results. If another form of zero padding is desired, it must be performed before `ifft2` is called.

Examples

```>>> import scipy.fft
>>> import numpy as np
>>> x = 4 * np.eye(4)
>>> scipy.fft.ifft2(x)
array([[1.+0.j,  0.+0.j,  0.+0.j,  0.+0.j], # may vary
[0.+0.j,  0.+0.j,  0.+0.j,  1.+0.j],
[0.+0.j,  0.+0.j,  1.+0.j,  0.+0.j],
[0.+0.j,  1.+0.j,  0.+0.j,  0.+0.j]])
```