C#编写的三次样条插值函数，TSS法求解对角矩阵方程函数，插值点函数值计算函数。-prepared by the cubic spline interpolation function, TSS method diagonal matrix equation function, interpolation function point value function.

三次样条插值法计算，采用自然边界条件，最终用TSS算法进行求解(Cubic spline interpolation)