If count=TRUE
and by.tree=FALSE
, a integer vector containing
frequencies that variables are used in the forest. If
by.tree=TRUE
, a matrix is returned, breaking down the counts by
tree (each column corresponding to one tree and each row to a variable).
If count=FALSE
and by.tree=TRUE
, a list of integer
indices is returned giving the variables used in the trees, else if
by.tree=FALSE
, a vector of integer indices giving the
variables used in the entire forest.