Model predicted f_exsitu vs. the ground truth. The different panels are models trained and validated by TNG100 and EAGLE in the top, and cross-validated with each other in the bottom, all with the combined parameters Sub0. For each column we show the one-to-one comparison in the top panel: r is $\sqrt{r^2}$; σ(Δf_exsitu) is the scatter of residual Δf_exsitu = f_{exsitu, predicted} − f_{exsitu, truth}; the solid black line marks y = x; and the dashed black line represents ±1σ(Δf_exsitu) scatter. The insets show the histogram of Δf_exsitu. In the bottom panel, we show the residual Δf_exsitu as a function of galaxy f_{exsitu, truth}: the red solid and dashed curves respectively show the running median and ±σ(Δf_exsitu) scatter.