statsmodels.robust.norms.AndrewWave.rho

AndrewWave.rho(z) [source]

The robust criterion function for Andrew’s wave.

Parameters:	z (array-like) – 1d array
Returns:	rho – rho(z) = a*(1-cos(z/a)) for |z| <= a*pi rho(z) = 2*a for |z| > a*pi
Return type:	array