Create an object of class '>polyX
from a dataset of transformed inputs and a vector that
describes the polynomial.
vect2polyXT(varnames, dataXT, monomials)
X-input names. A character vector of length equal to the number of X-inputs.
Transformed inputs. A data.frame with as many rows as observations, and as many columns as monomials.
Polynomial description. A character vector. Each element describes a monomial.
The input variables are coded either by their numbers, or by their
names. The character "*" denotes interaction between variables. See vect2polyX
example.