σ | 0.1 | 0.2 | 0.3 | 0.4 | 0.5 | 0.6 | 0.7 | 0.8 | 0.9 |
RMSE | 0 | 2.3547 × 10−11 | 2.4864 × 10−5 | 0.0026 | 0.0174 | 0.0423 | 0.0705 | 0.1011 | 0.1333 |