Cubic Spline(Custom Tool)
This is the "source-code" for the construction of a cubic-spline function from a list of points (here pointL).
The points have to be in ascending order of their x-coordinates (there is no test due to speed considerations). The algorithm used is LU-decomposition as it is explained in the attached PDF-file. Feel free to build a custom tool - also explained in the text and attached too.
