Power spectra and transfer function fractional errors (TFFE) for all three models. The solid, dotted, and dashed lines in the left column represent average power spectra for the whole test set (target, input, and prediction, respectively). The shading around the lines shows the sigma ranges. In the right column, the solid line represents the average TFFE for the prediction and the target, and the dashed line represents the same for the baseline and the target. This time, the shading represents the functional errors through partial derivatives.