scipy.fft.ihfft¶

scipy.fft.
ihfft
(x, n=None, axis= 1, norm=None, overwrite_x=False, workers=None, *, plan=None)[source]¶ Compute the inverse FFT of a signal that has Hermitian symmetry.
 Parameters
 xarray_like
Input array.
 nint, optional
Length of the inverse FFT, the number of points along transformation axis in the input to use. If n is smaller than the length of the input, the input is cropped. If it is larger, the input is padded with zeros. If n is not given, the length of the input along the axis specified by axis is used.
 axisint, optional
Axis over which to compute the inverse FFT. If not given, the last axis is used.
 norm{None, “ortho”}, optional
Normalization mode (see
fft
). Default is None. 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()
. Seefft
for more details. plan: object, optional
This argument is reserved for passing in a precomputed plan provided by downstream FFT vendors. It is currently not used in SciPy.
New in version 1.5.0.
 Returns
 outcomplex ndarray
The truncated or zeropadded input, transformed along the axis indicated by axis, or the last one if axis is not specified. The length of the transformed axis is
n//2 + 1
.
Notes
hfft
/ihfft
are a pair analogous torfft
/irfft
, but for the opposite case: here, the signal has Hermitian symmetry in the time domain and is real in the frequency domain. So, here, it’shfft
, for which you must supply the length of the result if it is to be odd: * even:ihfft(hfft(a, 2*len(a)  2) == a
, within roundoff error, * odd:ihfft(hfft(a, 2*len(a)  1) == a
, within roundoff error.Examples
>>> from scipy.fft import ifft, ihfft >>> spectrum = np.array([ 15, 4, 0, 1, 0, 4]) >>> ifft(spectrum) array([1.+0.j, 2.+0.j, 3.+0.j, 4.+0.j, 3.+0.j, 2.+0.j]) # may vary >>> ihfft(spectrum) array([ 1.0.j, 2.0.j, 3.0.j, 4.0.j]) # may vary