Gotchas#
PyWavelets utilizes NumPy
under the hood. That’s why handling the data
containing None
values can be surprising. None
values are converted to
‘not a number’ (numpy.NaN
) values:
>>> import numpy, pywt
>>> x = [None, None]
>>> mode = 'symmetric'
>>> wavelet = 'db1'
>>> cA, cD = pywt.dwt(x, wavelet, mode)
>>> numpy.all(numpy.isnan(cA))
True
>>> numpy.all(numpy.isnan(cD))
True
>>> rec = pywt.idwt(cA, cD, wavelet, mode)
>>> numpy.all(numpy.isnan(rec))
True