Figure 3 External validation results of the experimental vs. the calculated values for ACGC models of critical properties: (a) Tc, (b)Pc and (c) Vc.
3.2 Internal validation
Figure 4 shows the error distribution of application model and LOO-CV method. The results show that the error distribution of LOO-CV model is consistent and completely similar to the corresponding T c,P c, V c model, which further demonstrates the stability and robustness of these models based on groups, shape factor and topological location factors. In addition, Figure 5 showed the relationship between the experimental values and LOO-CV predicted values. Results showed that most of data points were distributed compactly around the diagonal. HighQ 2 values for the model indicated the stability of our models,which were 0.9826,0.9820 and 0.9978 for T c,P c and V c, respectively.