numpy.fft.rfftn(a, s=None, axes=None, norm=None)
[source]
Compute the N-dimensional discrete Fourier Transform for real input.
This function computes the N-dimensional discrete Fourier Transform over any number of axes in an M-dimensional real array by means of the Fast Fourier Transform (FFT). By default, all axes are transformed, with the real transform performed over the last axis, while the remaining transforms are complex.
Parameters: |
a : array_like Input array, taken to be real. s : sequence of ints, optional Shape (length along each transformed axis) to use from the input. ( axes : sequence of ints, optional Axes over which to compute the FFT. If not given, the last norm : {None, “ortho”}, optional New in version 1.10.0. Normalization mode (see |
---|---|
Returns: |
out : complex ndarray The truncated or zero-padded input, transformed along the axes indicated by |
Raises: |
ValueError If IndexError If an element of |
See also
The transform for real input is performed over the last transformation axis, as by rfft
, then the transform over the remaining axes is performed as by fftn
. The order of the output is as for rfft
for the final transformation axis, and as for fftn
for the remaining transformation axes.
See fft
for details, definitions and conventions used.
>>> a = np.ones((2, 2, 2)) >>> np.fft.rfftn(a) array([[[ 8.+0.j, 0.+0.j], [ 0.+0.j, 0.+0.j]], [[ 0.+0.j, 0.+0.j], [ 0.+0.j, 0.+0.j]]])
>>> np.fft.rfftn(a, axes=(2, 0)) array([[[ 4.+0.j, 0.+0.j], [ 4.+0.j, 0.+0.j]], [[ 0.+0.j, 0.+0.j], [ 0.+0.j, 0.+0.j]]])
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https://docs.scipy.org/doc/numpy-1.13.0/reference/generated/numpy.fft.rfftn.html