new("pdNatural",
...) or by the generic constructor function pdNatural.
Frequently the constructor is given a formula only, creating an
uninitialized pdNatural object which is later assigned a
value. pdNatural objects are primarily used to represent the
variance-covariance matrix or the precision matrix of random-effects
terms in mixed-effects models.
"pdMat", directly.pdMat-class