知道二阶导数边界条件的三次样条插值matlab程序，可以输出插值节点的值、每一段的插值多项式和各插值点的一阶导数值。-This is a matlab code of cubic spline interpolation when the second derivative of boundaries is known. This code can not only output the value of the interpolation node, it can also output every interpolation polynomial, more importantly, it is also can output the second derivative of each interpolation point.