numpy.polynomial.chebyshev.chebvander3d(x, y, z, deg)
Pseudo-Vandermonde matrix of given degrees.
Returns the pseudo-Vandermonde matrix of degrees
deg and sample points
(x, y, z). If
l, m, n are the given degrees in
x, y, z, then The pseudo-Vandermonde matrix is defined by
0 <= i <= l,
0 <= j <= m, and
0 <= j <= n. The leading indices of
V index the points
(x, y, z) and the last index encodes the degrees of the Chebyshev polynomials.
V = chebvander3d(x, y, z, [xdeg, ydeg, zdeg]), then the columns of
V correspond to the elements of a 3-D coefficient array
c of shape (xdeg + 1, ydeg + 1, zdeg + 1) in the order
np.dot(V, c.flat) and
chebval3d(x, y, z, c) will be the same up to roundoff. This equivalence is useful both for least squares fitting and for the evaluation of a large number of 3-D Chebyshev series of the same degrees and sample points.
New in version 1.7.0.
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