AdaptiveRandomForest-master/src/main/java/moa/classifiers/rules/core/splitcriteria/SDRSplitCriterionAMRules.java
/*
 *    SDRSplitCriterionAMRules.java
 *    Copyright (C) 2014 University of Porto, Portugal
 *    @author A. Bifet, J. Duarte, J. Gama
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 *    
 *    
 */
package moa.classifiers.rules.core.splitcriteria;

import moa.classifiers.core.splitcriteria.SDRSplitCriterion;
import moa.classifiers.core.splitcriteria.SplitCriterion;


public class SDRSplitCriterionAMRules extends SDRSplitCriterion implements AMRulesSplitCriterion {

	private static final long serialVersionUID = 1L;


	@Override
	public double getMeritOfSplit(double[] preSplitDist, double[][] postSplitDists) {
		double SDR=0.0;
		double N = preSplitDist[0];
		int count = 0; 

		for(int i = 0; i < postSplitDists.length; i++)
		{
			double Ni = postSplitDists[i][0];
			if(Ni >=0.05*preSplitDist[0]){
				count = count +1;
			}
		}
		if(count == postSplitDists.length){
			SDR = computeSD(preSplitDist);

			for(int i = 0; i < postSplitDists.length; i++)
			{
				double Ni = postSplitDists[i][0];
				SDR -= (Ni/N)*computeSD(postSplitDists[i]);

			}
		}
		return SDR;
	}



	@Override
	public double getRangeOfMerit(double[] preSplitDist) {
		return 1;
	}

	public double[] computeBranchSplitMerits(double[][] postSplitDists) {
		double[] SDR = new double[postSplitDists.length];
		double N = 0;

		for(int i = 0; i < postSplitDists.length; i++)
		{
			double Ni = postSplitDists[i][0];
			N += Ni;
		}
		for(int i = 0; i < postSplitDists.length; i++)
		{
			double Ni = postSplitDists[i][0];
			SDR[i] = (Ni/N)*computeSD(postSplitDists[i]);
		}
		return SDR;

	}


}
