Speedup of Bicubic Spline Interpolation

The paper seeks to introduce a new algorithm for computation of interpolating spline surfaces over non-uniform grids with \(C^2\) class continuity, generalizing a recently proposed approach for uniform grids originally based on a special approximation property between biquartic and bicubic polynomials. The algorithm breaks down the classical de Boor’s computational task to systems of equations with reduced size and simple remainder explicit formulas. It is shown that the original algorithm and the new one are numerically equivalent and the latter is up to 50% faster than the classic approach.