statsmodels.robust.norms.HuberT.rho#

HuberT.rho(z)[source]#

The robust criterion function for Huber’s t estimator

Parameters:
zarray_like

1d array

Returns:
rhondarray

The value of the robust criterion function.

\[\begin{split}\rho(z) = \begin{cases} \frac{z^2}{2} & \text{if } \lvert z \rvert \le t \\ \lvert z \rvert t - \frac{t^2}{2} & \text{if } \lvert z \rvert > t \end{cases}\end{split}\]