This example then specifies a smoothed spline interpolation method on the GRID statement. As shown by the following output, the resulting surface plot is smoother still. libname reflib ...

SIAM Journal on Numerical Analysis, Vol. 8, No. 1 (Mar., 1971), pp. 67-74 (8 pages) It is shown that if x ∈ C4[a, b] is approximated by a natural cubic spline, then ...

A general setting is given for smooth interpolating splines depending on a parameter such that as this parameter approaches infinity the spline converges to the piecewise linear interpolant. The ...