| package com.yahoo.labs.samoa.moa.classifiers.core.splitcriteria; |
| |
| /* |
| * #%L |
| * SAMOA |
| * %% |
| * Copyright (C) 2013 - 2014 Yahoo! Inc. |
| * %% |
| * 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. |
| * #L% |
| */ |
| |
| import com.yahoo.labs.samoa.moa.core.ObjectRepository; |
| import com.yahoo.labs.samoa.moa.options.AbstractOptionHandler; |
| import com.yahoo.labs.samoa.moa.tasks.TaskMonitor; |
| |
| public class VarianceReductionSplitCriterion extends AbstractOptionHandler implements SplitCriterion { |
| |
| private static final long serialVersionUID = 1L; |
| |
| /* @Override |
| public double getMeritOfSplit(double[] preSplitDist, double[][] postSplitDists) { |
| |
| double N = preSplitDist[0]; |
| double SDR = computeSD(preSplitDist); |
| |
| // System.out.print("postSplitDists.length"+postSplitDists.length+"\n"); |
| for(int i = 0; i < postSplitDists.length; i++) |
| { |
| double Ni = postSplitDists[i][0]; |
| SDR -= (Ni/N)*computeSD(postSplitDists[i]); |
| } |
| |
| return SDR; |
| }*/ |
| |
| @Override |
| public double getMeritOfSplit(double[] preSplitDist, double[][] postSplitDists) { |
| double SDR=0.0; |
| double N = preSplitDist[0]; |
| int count = 0; |
| |
| for (int i1 = 0; i1 < postSplitDists.length; i1++) { |
| double[] postSplitDist = postSplitDists[i1]; |
| double Ni = postSplitDist[0]; |
| if (Ni >= 5.0) { |
| 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 static double computeSD(double[] dist) { |
| |
| int N = (int)dist[0]; |
| double sum = dist[1]; |
| double sumSq = dist[2]; |
| // return Math.sqrt((sumSq - ((sum * sum)/N))/N); |
| return (sumSq - ((sum * sum)/N))/N; |
| } |
| |
| @Override |
| public void getDescription(StringBuilder sb, int indent) { |
| // TODO Auto-generated method stub |
| } |
| |
| @Override |
| protected void prepareForUseImpl(TaskMonitor monitor, |
| ObjectRepository repository) { |
| // TODO Auto-generated method stub |
| } |
| |
| } |