Abstract
Let x0,…,xN be N + 1 interpolation points (nodes) and 0,…,N be N + 1 interpolation data. Then every rational function r with numerator and denominator degress ⩽N interpolating these values can be written in its barycentric form completely determined by a vector u of N + 1 barycentric weights uk. Finding u is therefore an alternative to the determination of the coefficients in the canonical form of r; it is advantageous inasmuch as u contains information about unattainable points and poles.
In classical rational interpolation the numerator and the denominator of r are made unique (up to a constant factor) by restricting their respective degrees. We determine here the corresponding vectors u by applying a stabilized elimination algorithm to a matrix whose kernel is the space spanned by the . The method is of complexity O(n3) in terms of the denominator degree n; it seems on the other hand to be among the most stable ones.
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