_get_optimal_wavelet_scales(self, nSamples, dt, dj=0.25, s0=None)¶
Local helper to compute an “optimally spaced” set of scales for wavelet analysis
nSamples (int) – Sample-count (i.e., length) of time-series that is analyzed
dt (float) – Time-series step-size; temporal spacing between consecutive samples (1 / sampling rate)
dj (float) – Spectral resolution of scales. The choice of dj depends on the spectral width of the employed wavelet function. For instance,
dj = 0.5is the largest value that still yields adequate sampling in scale for the Morlet wavelet. Other wavelets allow larger values of dj while still providing sufficient spectral resolution. Small values of dj yield finer scale resolution.
scales – Set of scales to use in the wavelet transform
- Return type
The calculation of an “optimal” set of scales follows [ToCo98]. This routine is a local auxiliary method that is purely intended for internal use. Thus, no error checking is performed.
C. Torrence and G. P. Compo. A Practical Guide to Wavelet Analysis. Bulletin of the American Meteorological Society. Vol. 79, No. 1, January 1998.