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 ...
Spline theory and piecewise regression theory are integrated to provide a framework in which structural change is viewed as occurring in a smooth fashion. Specifically, structural change occurs at ...
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 ...