Ceres-Solver求解非线性最小二乘问题

• non-linear least square problem
  http://ceres-solver.org/nnls_tutorial.html

• how to regularized nonlinear least squares?
  https://groups.google.com/g/ceres-solver/c/vkv7nixkIYU?pli=1

ceres::Problem problem;
ceres::Solver::Options options;
ceres::Solver::Summary summary;

problem和option
定义问题+优化选项, summary为优化过程的verbose

  ResidualBlockId AddResidualBlock(
      CostFunction* cost_function,  # 代价函数
      LossFunction* loss_function,  # 损失函数
      const std::vector<double*>& parameter_blocks);  # 参数列表

loss_function can be nullptr, in which case the cost of the term is just the squared norm of the residuals.
即loss_function在未指定(nullptr)的情况下，即为residual的平方范数

cost_function和loss_function和Problem类(或实例化的对象)进行链接

loss_function通常用于减少outlier对cost_function的影响

BA优化：http://ceres-solver.org/nnls_tutorial.html#bundle-adjustment
.bz2文件解压：https://blog.51cto.com/u_11451275/5288808