关于aloam中的ceres-solver

 struct LidarEdgeFactor

    
 {
    
 	LidarEdgeFactor(Eigen::Vector3d curr_point_, Eigen::Vector3d last_point_a_,
    
 					Eigen::Vector3d last_point_b_, double s_)
    
 		: curr_point(curr_point_), last_point_a(last_point_a_), last_point_b(last_point_b_), s(s_) {}
    
  
    
 //在类里面重载一个模板函数，operator里面计算残差。前面两个参数是待优化的变量
    
 	template <typename T>
    
 	bool operator()(const T *q, const T *t, T *residual) const
    
 	{
    
  
    
 		Eigen::Matrix<T, 3, 1> cp{T(curr_point.x()), T(curr_point.y()), T(curr_point.z())};
    
 		Eigen::Matrix<T, 3, 1> lpa{T(last_point_a.x()), T(last_