fitted model objects of class gam as produced by gam().
Prints out the family, model formula, effective degrees of freedom for each smooth term, and optimized
value of the smoothness selection criterion used. See gamObject (or names(x)) for a listing
of what the object contains. summary.gam provides more detail.
Note that the optimized smoothing parameter selection criterion reported is one of GCV, UBRE(AIC), GACV,
negative log marginal likelihood (ML), or negative log restricted likelihood (REML).
If rank deficiency of the model was detected then the apparent rank is reported, along with the length of the cofficient vector
(rank in absense of rank deficieny). Rank deficiency occurs when not all coefficients are identifiable given the data. Although
the fitting routines (except gamm) deal gracefully with rank deficiency, interpretation of rank deficient models may be difficult.