Fitting splines

Dear all,

does anybody know about en easy way of fitting splines (maybe by using the TSpline classes)?

I face the problem to fit a profile with a combination of 2 range-wise defined functions for which I need a smooth transition. The boundaries of this transition region should be parameters of the fit itself. My idea was to use a 3rd order spline to accomplish this.
So far I’ve used spline interpolation only which gives already a fairly good result. However there are still some small bendings at the intersection points which I want to smooth out by allowing the fit to vary the knot positions.

Thanks in advance,


Did you try the TSpline3/TSpline5 classes ?
As input they accept TGraphs , etc


Dear René,

of course I’ve used the TSpline classes. But those classes are for interpolation only. I thought rather of a spline fit by moving the knots around.
Anyway, the problem is solved by using a polynomial which parameters are fixed by the boundary conditions of the adjacent fit functions.


Have a look at: