Therefore, relative to the full features, 256 or 512 features will be good for the KNN method with ECFPs, while feature selection has no impact on SVM, GBM and RF methods in our cases from the statistical analysis. It should be noted that DNN2 and DNN3 are excluded in our two-sample T-test due to very limited samples, thus the effect of the feature selection on DNN2 and DNN3 is not discussed.