| A | Calculation of the matrix A based on single dataset |
| est_ini | Initial estimation |
| link_grad | gradient of the link function |
| link_Hessian | Hessians of the link function |
| mean_psi | Sample expectation of psi |
| mean_psi_pop | Sample expectation of POP-Inf psi |
| optim_est | Gradient descent for obtaining estimator |
| optim_weights | Gradient descent for obtaining the weight vector |
| pop_M | POP-Inf M-Estimation |
| psi | Esimating equation |
| Sigma_cal | Variance-covariance matrix of the estimation equation |
| sim_data | Simulate the data for testing the functions |