Fig. 4. Learning curves for atomization energies (AE).

a Mean absolute error (MAE) of AE predictions on the test set, as a function of the number of training molecules n_train. The training sets were constructed using FPS with the extensive (a) and intensive kernels (b) (see text). c AE learning curves using molecular geometries obtained with the universal forcefield (UFF). The gray line represents a learning rate of $n_{\mathrm{train}}^{0.65}$ and serves as a guide to the eye in all three panels.