Add priors on the mean instead of assuming that the prior means are zero.
Add more reference in the doc.
Modify ARD in order to use a vector of hyperparameters for the precision instead of a single value.
Spelling : defaut -> default unless you insist on using french, spelling out ARD (Automatic Relevance Determination) regression in the docstring as in the comment line would be useful.

Thanks to Josef for the remarks.