approximating a curve



On 12/8/08, Valery Pipin <pip at iszf.irk.ru> wrote:

> real life example. Using the Peter's Eggleton stellar evolution code
>  I've got a table of  the stellar interior parameters for the Brown
>  Dwarf (0.2 M_sun, 0.006 L_sun). The parameters are pressure,
>  temperature, luminosity, density and etc.. . Now I want to use their
>  functional form in my dynamo model. The best way is to get the
>  Chebyshev approximations to them. I do as follows,
>  1) read the table to maxima
>  2) find the spline interpolation
>  3) find  the Chebyshev approximations

Hey, that rocks. But I don't quite understand what's going on here.
Why is there both a cubic spline and a Chebyshev approximation?
I would have expected one or the other.

As always it is encouraging to see examples of real work with Maxima.

Robert Dodier