Link.inverse_deriv2(z)[source]

Second derivative of the inverse link function g^(-1)(z).

Parameters
zarray_like

z is usually the linear predictor for a GLM or GEE model.

Returns
g’^(-1)(z)ndarray

The value of the second derivative of the inverse of the link function

Notes

This reference implementation gives the correct result but is inefficient, so it can be overridden in subclasses.