1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 package org.apache.commons.math.stat.descriptive.moment; 18 19 import java.io.Serializable; 20 21 import org.apache.commons.math.DimensionMismatchException; 22 23 /** 24 * Returns the arithmetic mean of the available vectors. 25 * @since 1.2 26 * @version $Revision: 619928 $ $Date: 2008-02-08 09:19:17 -0700 (Fri, 08 Feb 2008) $ 27 */ 28 public class VectorialMean implements Serializable { 29 30 /** Serializable version identifier */ 31 private static final long serialVersionUID = 8223009086481006892L; 32 33 /** Means for each component. */ 34 private Mean[] means; 35 36 /** Constructs a VectorialMean. 37 * @param dimension vectors dimension 38 */ 39 public VectorialMean(int dimension) { 40 means = new Mean[dimension]; 41 for (int i = 0; i < dimension; ++i) { 42 means[i] = new Mean(); 43 } 44 } 45 46 /** 47 * Add a new vector to the sample. 48 * @param v vector to add 49 * @exception DimensionMismatchException if the vector does not have the right dimension 50 */ 51 public void increment(double[] v) throws DimensionMismatchException { 52 if (v.length != means.length) { 53 throw new DimensionMismatchException(v.length, means.length); 54 } 55 for (int i = 0; i < v.length; ++i) { 56 means[i].increment(v[i]); 57 } 58 } 59 60 /** 61 * Get the mean vector. 62 * @return mean vector 63 */ 64 public double[] getResult() { 65 double[] result = new double[means.length]; 66 for (int i = 0; i < result.length; ++i) { 67 result[i] = means[i].getResult(); 68 } 69 return result; 70 } 71 72 /** 73 * Get the number of vectors in the sample. 74 * @return number of vectors in the sample 75 */ 76 public long getN() { 77 return (means.length == 0) ? 0 : means[0].getN(); 78 } 79 80 }