Module lagrange 

Polynomial interpolation through n points: the Lagrange form (direct evaluation) and the Newton divided-difference form (build coefficients once, evaluate cheaply).

Functions

lagrange_eval

Evaluate the Lagrange interpolating polynomial through (xs, ys) at x.

newton_coefficients

Newton divided-difference coefficients for (xs, ys) (the leading diagonal of the divided-difference table). Use with newton_eval.

newton_eval

Evaluate the Newton form (Horner over the nested products) at x.