08/12/2009, 07:02 PM

(08/12/2009, 06:40 PM)bo198214 Wrote: [ -> ]I also just see that there is a function lagrange_polynomial in sageWell that takes all the fun out of it, now doesn't it?

e.g.

# using the definition of Lagrange interpolation polynomial

sage: R = PolynomialRing(QQ, 'x')

sage: R.lagrange_polynomial([(0,1),(2,2),(3,-2),(-4,9)])

I mean this should be super easy now. Just plug in your argument-value-pairs and you have the interpolating polynomial (no matrix fuzz).

Then you can apply this interpolating polynomial to non-real values.

Or extract the coefficients as you like.

However I didnt check how long it takes

But seriously, I'll try both approaches and see which is faster.