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Ensemble methods, including Random Forest classifier and regressor

Ensemble Methods

Combining predictions of several base estimators is a general-purpose procedure for reducing the variance of a statistical learning method. When combined with bagging, ensemble models achive superior performance to individual estimators.

The main idea behind bagging (or bootstrap aggregation) is to fit the same base model to a big number of random subsets of the original training set and then aggregate their individual predictions to form a final prediction. In classification setting the overall prediction is the most commonly occurring majority class among the individual predictions.

In SmartCore you will find implementation of RandomForest - a popular averaging algorithms based on randomized decision trees. Random forests provide an improvement over bagged trees by way of a small tweak that decorrelates the trees. As in bagging, we build a number of decision trees on bootstrapped training samples. But when building these decision trees, each time a split in a tree is considered, a random sample of m predictors is chosen as split candidates from the full set of p predictors.

References:

Modules

Random forest classifier

Random forest regressor