Bivariate Lagrange interpolation at the Padua points: Computational aspects

Bivariate Lagrange interpolation at the Padua points: The generating curve approach

We give a simple, geometric and explicit construction of bivariate interpolation at certain points in a square (called Padua points), giving compact formulas for their fundamental Lagrange polynomials. We show that the associated norms of the interpolation operator, i.e., the Lebesgue constants, have minimal order of growth of O((log n)2). To the best of our knowledge this is the first complete...

Bivariate Lagrange interpolation at the Padua points: the ideal theory approach

The Padua points are a family of points on the square [−1, 1] given by explicit formulas that admits unique Lagrange interpolation by bivariate polynomials. Interpolation polynomials and cubature formulas based on the Padua points are studied from an ideal theoretic point of view, which leads to the discovery of a compact formula for the interpolation polynomials. The L convergence of the inter...

Hyperinterpolation at Xu Points and Interpolation at Padua Points in the Square: Computational Aspects

Bivariate Lagrange Interpolation at the Chebyshev Nodes

We discuss Lagrange interpolation on two sets of nodes in two dimensions where the coordinates of the nodes are Chebyshev points having either the same or opposite parity. We use a formula of Xu for Lagrange polynomials to obtain a general interpolation theorem for bivariate polynomials at either set of Chebyshev nodes. An extra term must be added to the interpolation formula to handle all poly...

Bivariate Interpolation at Xu Points: Results, Extensions and Applications

In a recent paper, Y. Xu proposed a set of Chebyshev-like points for polynomial interpolation on the square [−1, 1]. We have recently proved that the Lebesgue constant of these points grows like log of the degree (as with the best known points for the square), and we have implemented an accurate version of their Lagrange interpolation formula at linear cost. Here we construct non-polynomial Xu-...