Constructs natural cubic spline such that for every i in [0; X.Count-1] s(X[i]) = Y[i]. Must be X.Count = Y.Count. X must be already sorted. MinX = X[0], MaxX = X[X.Count-1].
Warning: we will copy references to X and Y ! So make sure that these objects are available for the life of this object. We will free in destructor X if OwnsX and free Y if OwnsY.