001/**
002 * Copyright (C) 2007 - 2016, Jens Lehmann
003 *
004 * This file is part of DL-Learner.
005 *
006 * DL-Learner is free software; you can redistribute it and/or modify
007 * it under the terms of the GNU General Public License as published by
008 * the Free Software Foundation; either version 3 of the License, or
009 * (at your option) any later version.
010 *
011 * DL-Learner is distributed in the hope that it will be useful,
012 * but WITHOUT ANY WARRANTY; without even the implied warranty of
013 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
014 * GNU General Public License for more details.
015 *
016 * You should have received a copy of the GNU General Public License
017 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
018 */
019package org.dllearner.algorithms.decisiontrees.utils;
020
021import org.apache.commons.math3.stat.StatUtils;
022
023/**
024 * Utils to compute statistics for classifier performance
025 * @author Utente
026 *
027 */
028public class MathUtils {
029        private static double mean;
030        private static double stddev;
031        public static double avg(double[] population) {
032                mean = StatUtils.mean(population);
033                return mean;
034        }
035        
036        public static double variance(double[] population) {
037                stddev = StatUtils.variance(population);
038                return stddev;
039        }
040//      public double[] sampling (int dimSample) {
041//              
042//              RandomDataGenerator randomData = new RandomDataGenerator(); 
043//              randomData.reSeed(2);
044//              for (int i = 0; i < dimSample; i++) {
045//                  double value = randomData.nextLong(1, 1000000);
046//              }
047//              return null;
048//      }
049
050        public static double stdDeviation(double[] population) {
051                stddev = StatUtils.variance(population);
052                return Math.sqrt(stddev);
053        }
054        
055        
056        
057
058}