Example usage for org.apache.mahout.classifier.df.data Dataset nblabels

Introduction

In this page you can find the example usage for org.apache.mahout.classifier.df.data Dataset nblabels.

Prototype

public int nblabels() 

Source Link

Usage

From source file:com.wsc.myexample.decisionForest.MyDecisionForest.java

License:Apache License

/**
 * predicts the label for the instance//from   ww w  .  j  ava 2s  .co  m
 * 
 * @param rng
 *          Random number generator, used to break ties randomly
 * @return -1 if the label cannot be predicted
 */
public double classify(Dataset dataset, Random rng, Instance instance) {
    if (dataset.isNumerical(dataset.getLabelId())) {
        double sum = 0;
        int cnt = 0;
        for (Node tree : trees) {
            double prediction = tree.classify(instance);
            if (prediction != -1) {
                sum += prediction;
                cnt++;
            }
        }
        return sum / cnt;
    } else {
        int[] predictions = new int[dataset.nblabels()];
        for (Node tree : trees) {
            double prediction = tree.classify(instance);
            if (prediction != -1) {
                predictions[(int) prediction]++;
            }
        }

        if (DataUtils.sum(predictions) == 0) {
            return -1; // no prediction available
        }

        return DataUtils.maxindex(rng, predictions);
    }
}

---