numpy.fft.irfft2

fft.irfft2(a, s=None, axes=(-2, -1), norm=None, out=None)[source]

Computes the inverse of rfft2.

Parameters:

aarray_like

The input array

ssequence of ints, optional

Shape of the real output to the inverse FFT.

Changed in version 2.0: If it is -1, the whole input is used (no padding/trimming).

Deprecated since version 2.0: If s is not None, axes must not be None either.

Deprecated since version 2.0: s must contain only int s, not None values. None values currently mean that the default value for n is used in the corresponding 1-D transform, but this behaviour is deprecated.

axessequence of ints, optional

The axes over which to compute the inverse fft. Default: (-2, -1), the last two axes.

Deprecated since version 2.0: If s is specified, the corresponding axes to be transformed must not be None.

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

Normalization mode (see numpy.fft). Default is “backward”. Indicates which direction of the forward/backward pair of transforms is scaled and with what normalization factor.

New in version 1.20.0: The “backward”, “forward” values were added.

outndarray, optional

If provided, the result will be placed in this array. It should be of the appropriate shape and dtype for the last transformation.

New in version 2.0.0.

Returns:

outndarray

The result of the inverse real 2-D FFT.

See also

rfft2

The forward two-dimensional FFT of real input, of which irfft2 is the inverse.

rfft

The one-dimensional FFT for real input.

irfft

The inverse of the one-dimensional FFT of real input.

irfftn

Compute the inverse of the N-dimensional FFT of real input.

Notes

This is really irfftn with different defaults. For more details see irfftn.

Examples

Try it in your browser!

>>> import numpy as np
>>> a = np.mgrid[:5, :5][0]
>>> A = np.fft.rfft2(a)
>>> np.fft.irfft2(A, s=a.shape)
array([[0., 0., 0., 0., 0.],
       [1., 1., 1., 1., 1.],
       [2., 2., 2., 2., 2.],
       [3., 3., 3., 3., 3.],
       [4., 4., 4., 4., 4.]])

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