对于已经给出的横坐标及对应的函数值，进行三次样条插值。边界条件为二阶导数为0。 需要的追赶法程序也在内。另外还有高斯消去法和gauss-jordan法求逆矩阵的程序(Two of the programes are aming to solving the problem of cubic interpolation with the boundary condition of the zero second-order derivation. The programe of the chasi