rfftn#
- scipy.fft.rfftn(x, s=None, axes=None, norm=None, overwrite_x=False, workers=None, *, plan=None)[source]#
- Compute the N-D discrete Fourier Transform for real input. - This function computes the N-D discrete Fourier Transform over any number of axes in an M-D 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:
- xarray_like
- Input array, taken to be real. 
- ssequence of ints, optional
- Shape (length along each transformed axis) to use from the input. ( - s[0]refers to axis 0,- s[1]to axis 1, etc.). The final element of s corresponds to n for- rfft(x, n), while for the remaining axes, it corresponds to n for- fft(x, n). Along any 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.
- axessequence of ints, optional
- Axes over which to compute the FFT. If not given, the last - len(s)axes are used, or all axes if s is also not specified.
- 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 - fftfor more details.
- workersint, optional
- Maximum number of workers to use for parallel computation. If negative, the value wraps around from - os.cpu_count(). See- fftfor 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. - Added in version 1.5.0. 
 
- Returns:
- outcomplex ndarray
- The truncated or zero-padded input, transformed along the axes indicated by axes, or by a combination of s and x, as explained in the parameters section above. The length of the last axis transformed will be - s[-1]//2+1, while the remaining transformed axes will have lengths according to s, or unchanged from the input.
 
- Raises:
- ValueError
- If s and axes have different length. 
- IndexError
- If an element of axes is larger than the number of axes of x. 
 
 - See also - Notes - 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- rfftfor the final transformation axis, and as for- fftnfor the remaining transformation axes.- See - fftfor details, definitions and conventions used.- Examples - >>> import scipy.fft >>> import numpy as np >>> x = np.ones((2, 2, 2)) >>> scipy.fft.rfftn(x) array([[[8.+0.j, 0.+0.j], # may vary [0.+0.j, 0.+0.j]], [[0.+0.j, 0.+0.j], [0.+0.j, 0.+0.j]]]) - >>> scipy.fft.rfftn(x, axes=(2, 0)) array([[[4.+0.j, 0.+0.j], # may vary [4.+0.j, 0.+0.j]], [[0.+0.j, 0.+0.j], [0.+0.j, 0.+0.j]]])