Table 4 Optimization points for regression models.

From: Reliable and efficient solar radiation estimation with the insights of XAI

Model

Key parameters

Optimization strategies

Decision tree

max_depth, min_samples_leaf, criterion

1. Limit tree depth to reduce overfitting.

2. Use grid search with cross-validation.

Random forest

n_estimators, max_features, max_depth

1. Increase n_estimators until OOB error stabilizes.

2. Tune max_features for bias–variance control.

AdaBoost

n_estimators, learning_rate

1.Balance n_estimators and learning_rate.

2. Use shallow base learners (depth 1–3).

Gradient boosting

learning_rate, n_estimators, subsample

1. Use small learning_rate with more estimators.

2. Apply early stopping for generalization.

XGBoost

eta, max_depth, subsample, lambda

1. Tune regularization (lambda, alpha).

2. Use early stopping and balanced learning rate.