This function is used to represent a polynomial term in a model
formula.
It computes the homogeneous terms in the polynomial of degree n
in one variable x or two variables x,y.
polynom(x, …)A numerical vector.
Either a single integer n specifying the degree of the polynomial,
or two arguments y,n giving another vector of data y
and the degree of the polynomial.
A numeric matrix, with rows corresponding to the entries of x,
and columns corresponding to the terms in the polynomial.
This function is typically used inside a model formula
in order to specify the most general possible polynomial
of order n involving one numerical variable x
or two numerical variables x,y.
It is equivalent to poly(, raw=TRUE).
If only one numerical vector argument x is given,
the function computes the vectors x^k for
k = 1, 2, …, n. These vectors are combined into a matrix
with n columns.
If two numerical vector arguments x,y are given,
the function computes the vectors x^k * y^m for
k >= 0 and m >= 0 satisfying
0 < k + m <= n. These vectors are combined into a matrix
with one column for each homogeneous term.
# NOT RUN {
x <- 1:4
y <- 10 * (0:3)
polynom(x, 3)
polynom(x, y, 3)
# }
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