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iFit/cwt

PURPOSE ^

b = cwt(s,dim,scales,wname,'wname',...) : Continuous wavelet transform

SYNOPSIS ^

function s = cwt(a,dim,scales,wname,plotit)

DESCRIPTION ^

 b = cwt(s,dim,scales,wname,'wname',...) : Continuous wavelet transform

   @iData/cwt function to return the Continuous wavelet transform of data sets
     The continuous wavelet transform performs a multi-scale component analysis
     It expands the data set into frequency space.

     b = cwt(s,scales,'wname') computes the continuous wavelet coefficients 
       of the signal vector x at real, positive scales, using wavelet 'wname'
     b = cwt(..., 'plot') plots the continuous wavelet transform power spectra
          plot(log(abs(b).^2))
       You can optionally use slice-o-matic for an interactive inspection with:         
          slice(log(abs(b).^2)) for initial 2D data sets (3D result)

     The resulting object has dimension of the input plus a 'period' axis,
     and contains the wavelet decomposition coeficients (e.g. complex).
     The low period contribution indicates sharp features, whereas the high
     period ones indicate slow variation/constant contributions.
     For easier interpretation you can compute the power spectrum abs(b).^2   

 input:  s:      object or array (iData)
         dim:    axis rank upon which to perform the wavelet analysis (default=1)
         scales: Number of scales or scale range (default=[] for automatic)
         wname:  Wavelet Family Short Name among 'Morlet','Paul','Dog' (default='Morlet')
         'plot': request plotting of the continuous wavelet transform coefficients

 output: b: wavelet transform object or array (iData)
 ex:     b=cwt(a); b=cwt(a,1,1:32,'plot')

 Reference: Grinsted, A., Moore, J.C., Jevrejeva, S. (2004) Application of the 
              cross wavelet transform and wavelet coherence to geophysical time 
              series, Nonlin. Processes Geophys., 11, 561–566, doi:10.5194/npg-11-561-2004
            Wavelet software was provided by C. Torrence and G. Compo,
              and is available at URL: http://paos.colorado.edu/research/wavelets/
 http://noc.ac.uk/using-science/crosswavelet-wavelet-coherence
 http://en.wikipedia.org/wiki/Continuous_wavelet_transform

 Version: Mar. 22, 2017
 See also iData, iData/fft, iData/xcorr, iData/conv

CROSS-REFERENCE INFORMATION ^

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