说明：  阻尼高斯牛顿算法，解最小二乘问题的理论说明及源代码。用高斯牛顿法求方向，armijo线性搜索得到步长。
(Damping Gauss-Newton algorithm, the theoretical description of least squares problem solution and source code. Gauss-Newton method for direction, armijo linear search to get step.)