中文说明：病态方程组求解的matlab程序，涵盖LU分解、Jacobi迭代、GS迭代、SOR迭代四种方法，通过输入参数M来选去对应的算法。
English Description：
The matlab program for solving ill conditioned equations covers LU decomposition, Jacobi iteration, GS iteration and SOR iteration. The corresponding algorithm is selected by inputting parameter M.