The object
can be a fitted model of any kind,
including models of the classes lm
, glm
and ppm
. To be precise,
object
must belong to a class for which there are methods
for formula
, terms
and model.matrix
.
The command model.depends
determines the relationship between
the original covariates (the data supplied when object
was
fitted) and the canonical covariates (the columns of the design matrix).
It returns a logical matrix, with one row for each canonical
covariate, and one column for each of the original covariates,
with the i,j
entry equal to TRUE
if the
i
th canonical covariate depends on the j
th
original covariate.
The command model.is.additive
determines whether the model
is additive, in the sense that there is no canonical covariate that
depends on two or more original covariates. It returns a logical value.