statsmodels.genmod.families.family.Poisson.loglike_obs¶
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Poisson.
loglike_obs
(endog, mu, var_weights=1.0, scale=1.0)[source]¶ The log-likelihood function for each observation in terms of the fitted mean response for the Poisson distribution.
Parameters: endog : ndarray
Usually the endogenous response variable.
mu : ndarray
Usually but not always the fitted mean response variable.
var_weights : array_like
1d array of variance (analytic) weights. The default is 1.
scale : float
The scale parameter. The default is 1.
Returns: ll_i : float
The value of the loglikelihood evaluated at (endog, mu, var_weights, scale) as defined below.
Notes
\[ll_i = var\_weights_i / scale * (endog_i * \ln(\mu_i) - \mu_i - \ln \Gamma(endog_i + 1))\]