谁来帮帮我啊:运用三次样条插值函数法对一条已知的折线进行圆滑（编程实现）。

matlab算么？
function output = spline(x,y,xx)
%SPLINE Cubic spline data interpolation.
% PP = SPLINE(X,Y) provides the piecewise polynomial form of the
% cubic spline interpolant to the data values Y at the data sites X,
% for use with the evaluator PPVAL and the spline utility UNMKPP.
% X must be a vector.
% If Y is a vector, then Y(j) is taken as the value to be matched at X(j),
% hence Y must be of the same length as X -- see below for an exception
% to this.
% If Y is a matrix or ND array, then Y(:,...,:,j) is taken as the value to
% be matched at X(j), hence the last dimension of Y must equal length(X) --
% see below for an exception to this.
%
% YY = SPLINE(X,Y,XX) is the same as YY = PPVAL(SPLINE(X,Y),XX), thus
% providing, in YY, the values of the interpolant at XX. For information
% regarding the size of YY see PPVAL.
%
% Ordinarily, the not-a-knot end co