This method function updates each element of object, allowing
the access to data.
# S3 method for modelStruct
update(object, data, …)an object inheriting from class "modelStruct",
representing a list of model components, such as corStruct and
varFunc objects.
a data frame in which to evaluate the variables needed for
updating the elements of object.
some methods for this generic require additional arguments. None are used in this method.
an object similar to object (same class, length, and names),
but with updated elements.