class statsmodels.robust.norms.AndrewWave(a=1.339)[source]

Andrew’s wave for M estimation.

Parameters:a (float, optional) – The tuning constant for Andrew’s Wave function. The default value is 1.339.


psi(z) The psi function for Andrew’s wave
psi_deriv(z) The derivative of Andrew’s wave psi function
rho(z) The robust criterion function for Andrew’s wave.
weights(z) Andrew’s wave weighting function for the IRLS algorithm