【1】 spap2() SPAP2 Least squares spline approximation. SPAP2(KNOTS,K,X,Y) returns the B-form of the least-squares approximation f to the data X, Y by splines of order K with knot sequence KNOTS. The spline approximates, at the data site X(j), the given data value Y(:,j), j=1:length(X).【2】spaps()SPAPS Smoothing spline. [SP,VALUES] = SPAPS(X,Y,TOL) returns the B-form and, if asked, the values at X, of a cubic smoothing spline f to the data X, Y. The smoothing spline approximates, at the data site X(j), the given data value Y(:,j), j=1:length(X). The data values may be scalars, vectors, matrices, or even ND-arrays.