说明：  基于三对角矩阵LU分解的追赶法，编写的追赶法分解五对角矩阵，并在此基础上解以五对角为系数矩阵的线性方程组。
(Tridiagonal matrix based on LU decomposition method to catch up, catch up with the preparation of the Decomposition of five pairs of diagonal matrix, and on this basis for the solution to five diagonal coefficient matrix of linear equations.)