object includes a varStruct component, the inverse of
the standard deviations of the variance function structure represented
by the corresponding varFunc object are returned; else, a
vector of ones of length equal to the number of observations in the
data frame used to fit the associated linear model is returned.varWeights(object)glsStruct,
representing a list of linear model components, such as
corStruct and varFunc objects.object includes a varStruct component, a vector with
the corresponding variance weights; else, or a vector of ones.varWeights