Usage

Typical Usage

Majority, if not all, methods follow the same usage pattern:

  • Import method
  • Initiate method
  • Apply method on data

On vanilla EMD this is as

from PyEMD import EMD
emd = EMD()
imfs = emd(s)

Parameters

The decomposition can be changed by adjusting parameters related to either sifting or stopping conditions.

Sifting

The sifting depends on the used method so these parameters ought to be looked within the methods. However, the typical parameters relate to spline method or the number of mirroring points.

Stopping conditions

All methods have the same two conditions, FIXE and FIXE_H, for stopping which relate to the number of sifting iterations. Setting parameter FIXE to any positive value will fix the number of iterations for each IMF to be exactly FIXE.

Example:

emd = EMD()
emd.FIXE = 10
imfs = emd(s)

Parameter FIXE_H relates to the number of iterations when the proto-IMF signal fulfils IMF conditions, i.e. number of extrema and zero-crossings differ at most by one and the mean is close to zero. This means that there will be at least FIXE_H iteration per IMF.

Example:

emd = EMD()
emd.FIXE_H = 5
imfs = emd(s)

When both FIXE and FIXE_H are 0 then other conditions are checked. These can be checking for convergence between consecutive iterations or whether the amplitude of output is below acceptable range.