Fig. 4:

Perturbation with various tuning parameters. (a) Figure 4a compares the performance with various choices of $\lambda :\lambda =\lambda \max +\gamma \left({\lambda }_{\min }-{\lambda }_{\max }\right),\text{where}{\lambda }_{\min }$ and λ_max are the minimum and maximum of regularization parameters selected by 1,000 replicates of cross-validation; (b) Number of permutation; (c) Number of bootstrap.