A reference class (see mother class definition
"" for a mixed-effects model predictor
module with a dense model matrix for the fixed-effects parameters.
The reference class is associated with a C++ class of the same name.
As is customary, the generator object, merPredD, for the
class has the same name as the class.
showClass("merPredD")
pp <- slot(lmer(Yield ~ 1|Batch, Dyestuff), "pp")
stopifnot(is(pp, "merPredD"))
str(pp) # an overview of all fields and methods' names.