statsmodels.robust.norms.TukeyBiweight.weights#
- TukeyBiweight.weights(z)[source]#
Tukey’s biweight weighting function for the IRLS algorithm
The psi function scaled by z.
- Parameters:
- zarray_like
1d array
- Returns:
- weights
ndarray The value of the weighting function.
\[\begin{split}\text{weights}(z) = \begin{cases} (1 - (\frac{z}{c})^2)^2 & \text{if } \lvert z \rvert \le c \\ 0 & \text{if } \lvert z \rvert > c \end{cases}\end{split}\]
- weights