org.jpmml.evaluator.RegressionAggregator.java Source code

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Here is the source code for org.jpmml.evaluator.RegressionAggregator.java

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/*
 * Copyright (c) 2015 Villu Ruusmann
 *
 * This file is part of JPMML-Evaluator
 *
 * JPMML-Evaluator is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * JPMML-Evaluator is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with JPMML-Evaluator.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.jpmml.evaluator;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import com.google.common.base.Function;
import com.google.common.primitives.Doubles;
import org.apache.commons.math3.stat.descriptive.rank.Percentile;

class RegressionAggregator {

    private List<Double> values = new ArrayList<>();

    public int size() {
        return this.values.size();
    }

    public void clear() {
        this.values.clear();
    }

    public void add(Double value) {
        this.values.add(value);
    }

    public Double sum() {
        Function<List<Double>, Double> function = new Function<List<Double>, Double>() {

            @Override
            public Double apply(List<Double> values) {
                return sum(values);
            }
        };

        return transform(function);
    }

    public Double median() {
        Function<List<Double>, Double> function = new Function<List<Double>, Double>() {

            @Override
            public Double apply(List<Double> values) {
                return median(values);
            }
        };

        return transform(function);
    }

    public Double average(final double denominator) {
        Function<List<Double>, Double> function = new Function<List<Double>, Double>() {

            @Override
            public Double apply(List<Double> values) {
                return sum(values) / denominator;
            }
        };

        return transform(function);
    }

    protected Double transform(Function<List<Double>, Double> function) {
        return function.apply(this.values);
    }

    static double sum(List<Double> values) {
        double result = 0d;

        for (Double value : values) {
            result += value.doubleValue();
        }

        return result;
    }

    static double median(List<Double> values) {
        double[] data = Doubles.toArray(values);

        // The data must be ordered
        Arrays.sort(data);

        Percentile percentile = new Percentile();
        percentile.setData(data);

        return percentile.evaluate(50);
    }
}