[SciPy-user] Interpolation polynomials

[Anne Archibald]

On 22/08/07, Matthieu Brucher <matthieu.brucher at gmail.com> wrote:

> > Does scipy/numpy have an alternate
> > polynomial representation based on the product of zeros rather than
> > monomial coefficients? If not, is there a better way to do this than
> > generating code to do this?
>
> The poly1d returns a new object with the roots, but the value is computed
> with polyval :( I don't know if there is another fnction to evaluate a
> polynomial.

In this particular context - the interpolating polynomial - there is
an algorithm for evaluating it more-or-less directly. In Numerical
Recipes in C (which used to be freely available; they now need some
kind of peculiar plugin to read their book), they describe Neville's
algorithm for computing values of the interpolating polynomial.

Anne