According to the results of the combined study of the chemical structure and key GUTFW parameters in ML, the parameters are highly important in the prediction of Fa. Therefore, to quantify their importance, we calculated the Gini index, and the results are shown in Figure . Pn was the most important parameter with a Gini index of 17.9. Dn ranked third with a Gini index of 7.5. Do ranked 14th among all 38 descriptors, with a Gini index of 2.0. Based on these results, all three key GUTFW parameters are important for Fa prediction in the combined RF model.