statsmodels.discrete.discrete_model.Poisson.loglike¶

Poisson.loglike(params)[source]¶

Loglikelihood of Poisson model

Parameters:

params : array-like

The parameters of the model.

Returns:

loglike : float

The log-likelihood function of the model evaluated at params. See notes.

Notes

$\ln L=\sum_{i=1}^{n}\left[-\lambda_{i}+y_{i}x_{i}^{\prime}\beta-\ln y_{i}!\right]$