statsmodels.robust.norms.HuberT.rho¶ HuberT.rho(z)[source]¶ The robust criterion function for Huber’s t. Parameters:¶ z : array_like¶1d array Returns:¶ rho – rho(z) = .5*z**2 for |z| <= t rho(z) = |z|*t - .5*t**2 for |z| > t Return type:¶ ndarray