mlda.attributes.MeanSkewnessNumericAttributes.java Source code

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Here is the source code for mlda.attributes.MeanSkewnessNumericAttributes.java

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/*
 * This file is part of the MLDA.
 *
 * (c)  Jose Maria Moyano Murillo
 *      Eva Lucrecia Gibaja Galindo
 *      Sebastian Ventura Soto <sventura@uco.es>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

package mlda.attributes;

import java.util.Set;

import mlda.base.MLDataMetric;
import mulan.data.MultiLabelInstances;
import weka.core.Attribute;
import weka.core.Instance;
import weka.core.Instances;

/**
* Class implementing the Mean of skewness of numeric attributes
*
* @author Jose Maria Moyano Murillo
*/
public class MeanSkewnessNumericAttributes extends MLDataMetric {

    /**
     * Constructor
     */
    public MeanSkewnessNumericAttributes() {
        super("Mean of skewness of numeric attributes");
    }

    /**
     * Calculate metric value
     * 
     * @param mlData Multi-label dataset to which calculate the metric
     * @return Value of the metric
     */
    public double calculate(MultiLabelInstances mlData) {
        Instances instances = mlData.getDataSet();
        int nInstances = mlData.getNumInstances();

        Set<Attribute> attributesSet = mlData.getFeatureAttributes();

        int nNumeric = 0;
        double mean = 0;
        double avg;
        double var;
        double stdev;

        for (Attribute att : attributesSet) {
            if (att.isNumeric()) {
                nNumeric++;
                avg = instances.meanOrMode(att);
                var = 0;
                for (Instance inst : instances) {
                    var += Math.pow(inst.value(att) - avg, 3);
                }
                stdev = Math.sqrt(instances.variance(att));
                mean += nInstances * var / ((nInstances - 1) * (nInstances - 2) * Math.pow(stdev, 3));
            }
        }

        if (nNumeric > 0) {
            this.value = mean / nNumeric;
        } else {
            this.value = Double.NaN;
        }

        //this.value = mean;
        return value;
    }

}