Constructs the design matrix used to fit a polywog model,
similar to model.matrix.lm.
# S3 method for polywog
model.matrix(object, type = c("raw", "expanded"), ...)a fitted model of class "polywog"
"raw", the default, returns the non-expanded model
matrix with no intercept (same number of columns as
object$polyTerms). "expanded" returns the polynomial
expansion used in fitting (number of columns equals
length(object$coefficients)).
other arguments to be passed to further methods (typically only used internally)
The design matrix of the specified model, consisting either of raw
terms or the full polynomial expansion depending on the type
argument.
There are two types of model matrix a user might want to construct.
First, there is the matrix of the raw input terms that go into the
eventual polynomial expansion. Such a matrix can be obtained by using
type = "raw" (the default). The other form of the model matrix is
the full polynomial expansion, where each column contains some power of
the raw inputs. This can be obtained by using type = "expanded".