Extracts the Watanabe-Akaike Information Criterion from objects of class
Bwiqid which have a WAIC attribute.
a fitted model object with an attribute giving the WAIC and pD for the fitted model.
optionally more fitted model objects.
If just one object is provided, the corresponding WAIC.
If multiple objects are provided, a data frame with rows corresponding to the objects and columns representing the number of parameters in the model (pD) and the WAIC.
The code to produce WAIC is new and not fully tested: it probably harbours bugs!
Burnham, K P; D R Anderson 2002. Model selection and multimodel inference: a practical information-theoretic approach. Springer-Verlag.