object
an object inheriting from class gnlsStruct,
representing a list of model components, such as
corStruct and varFunc objects, and attributes
specifying the underlying nonlinear model and the response variable.
conLin
an optional condensed linear model object, consisting of
a list with components "Xy", corresponding to a regression
matrix (X) combined with a response vector (y), and
"logLik", corresponding to the log-likelihood of the
underlying nonlinear model. Defaults to attr(object,
"conLin").