class<class 'statsmodels.genmod.families.links.log'>)[source]

Poisson exponential family.


link : a link instance, optional

The default link for the Poisson family is the log link. Available links are log, identity, and sqrt. See for more information.

Attributes (a link instance) The link function of the Poisson instance.
Poisson.variance (varfuncs instance) variance is an instance of


deviance(endog, mu[, scale]) Poisson deviance function
fitted(lin_pred) Fitted values based on linear predictors lin_pred.
loglike(endog, mu[, scale]) Loglikelihood function for Poisson exponential family distribution.
predict(mu) Linear predictors based on given mu values.
resid_anscombe(endog, mu) Anscombe residuals for the Poisson exponential family distribution
resid_dev(endog, mu[, scale]) Poisson deviance residual
starting_mu(y) Starting value for mu in the IRLS algorithm.
weights(mu) Weights for IRLS steps