Vandermonde matrix of given degree.
Returns the Vandermonde matrix of degree deg and sample points x. The Vandermonde matrix is defined by
where 0 <= i <= deg. The leading indices of V index the elements of x and the last index is the power of x.
If c is a 1-D array of coefficients of length n + 1 and V is the matrix V = polyvander(x, n), then np.dot(V, c) and polyval(x, c) are the same up to roundoff. This equivalence is useful both for least squares fitting and for the evaluation of a large number of polynomials of the same degree and sample points.
x : array_like
deg : int
vander : ndarray.