statsmodels.genmod.families.links.NegativeBinomial.deriv2¶

NegativeBinomial.deriv2(p)[source]¶

Second derivative of the negative binomial link function.

Parameters:	p (array-like) – Mean parameters
Returns:	g’‘(p) – The second derivative of the negative binomial transform link function
Return type:	array

Notes

g’‘(x) = -(1+2*alpha*x)/(x+alpha*x^2)^2