| cv.interep | k-folds cross-validation for interep |
| dat | simulated data for demonstrating the features of interep |
| dmcp | This function obtains the first derivative function of MCP (Minimax Concave Penalty) |
| interep | fit generalized estimaitng equations with given tuning parameters |
| penalty | This function gives the penalty functions |
| reformat | This function changes the format of the longitudinal data from wide format to long format |