说明：  自编数学函数调用库,有LU分解法,高斯塞德尔迭代法,追赶法解线性方程组,还有一维和二维的高斯积分公式
(Self-compiled mathematical function call library, LU decomposition method, Gao Si Seidel iteration method, catch-up method to solve linear equations, there are one and two dimensional Gao Si integral formula)