[Rd] Inconsistency in AIC values for glm with family poisson (PR#8840)

[x.sole at iconcologia.net]

Full_Name: Xavier Solé
Version: 2.3.0
OS: Windows XP SP2
Submission from: (NULL) (213.151.99.160)


#When computing AIC for one of the models shown in ?glm we get an inconsistent
AIC value. We also get the same wrong value if we use "extractAIC" o "AIC"
functions.

example(glm)

glm.D93

extractAIC(glm.D93)

#AIC of this model should be 15.129 (residual deviance + 2*effective degrees of
freedom), but the AIC which R returns is 56.76. Function extractAIC returns the
right number of effective degrees of freedom (5), but anyway seems to fail in
calculating the correct AIC value.