Table 1. Average MAE, RMSE, and Dataset Size with Standard Deviations from 5-Fold Cross-Validation Given in Parentheses of Combinations of Active Learning Hyperparameters Evaluated by Training cNNPs with an Oxalic Acid CSP Landscapea.
| entry | training quantity | committee size | % uncertain target | batch size | energy MAE (kJ mol–1) | energy RMSE (kJ mol–1) | final training set size |
|---|---|---|---|---|---|---|---|
| 1 | E | 6 | 10.0 | 30 | 1.11 (0.05) | 1.74 (0.18) | 852 (24) |
| 2 | E, F | 6 | 10.0 | 30 | 1.08 (0.10) | 1.50 (0.13) | 546 (40) |
| 3 | ΔE | 6 | 10.0 | 30 | 1.09 (0.11) | 1.47 (0.18) | 205 (53) |
| 4 | ΔE, ΔF | 6 | 10.0 | 30 | 0.92 (0.06) | 1.20 (0.07) | 216 (22) |
| 5 | ΔE | 6 | 2.5 | 30 | 0.89 (0.11) | 1.21 (0.20) | 354 (72) |
| 6 | ΔE | 6 | 5.0 | 30 | 0.97 (0.06) | 1.29 (0.10) | 252 (45) |
| 7 | ΔE | 2 | 5.0 | 30 | 1.19 (0.18) | 1.61 (0.26) | 168 (65) |
| 8 | ΔE | 18 | 5.0 | 30 | 0.90 (0.06) | 1.20 (0.12) | 288 (41) |
| 9 | ΔE | 6 | 5.0 | 15 | 1.01 (0.05) | 1.37 (0.17) | 216 (15) |
| 10 | ΔE | 6 | 5.0 | 60 | 0.90 (0.08) | 1.38 (0.43) | 320 (45) |
The cNNPs were trained either on total energy (E)/forces (F) or the difference between the force field (FIT + DMA) values and the reference values (ΔE/ΔF), i.e., Δ-learning. All entries used an uncertainty cutoff of 1.0 kJ mol–1, with candidates selected by highest uncertainty.