001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 package org.apache.commons.math.stat.descriptive; 018 019 import org.apache.commons.math.MathRuntimeException; 020 021 /** 022 * Abstract base class for all implementations of the 023 * {@link UnivariateStatistic} interface. 024 * <p> 025 * Provides a default implementation of <code>evaluate(double[]),</code> 026 * delegating to <code>evaluate(double[], int, int)</code> in the natural way. 027 * </p> 028 * <p> 029 * Also includes a <code>test</code> method that performs generic parameter 030 * validation for the <code>evaluate</code> methods.</p> 031 * 032 * @version $Revision: 894705 $ $Date: 2009-12-30 15:24:54 -0500 (Wed, 30 Dec 2009) $ 033 */ 034 public abstract class AbstractUnivariateStatistic 035 implements UnivariateStatistic { 036 037 /** 038 * {@inheritDoc} 039 */ 040 public double evaluate(final double[] values) { 041 test(values, 0, 0); 042 return evaluate(values, 0, values.length); 043 } 044 045 /** 046 * {@inheritDoc} 047 */ 048 public abstract double evaluate(final double[] values, final int begin, final int length); 049 050 /** 051 * {@inheritDoc} 052 */ 053 public abstract UnivariateStatistic copy(); 054 055 /** 056 * This method is used by <code>evaluate(double[], int, int)</code> methods 057 * to verify that the input parameters designate a subarray of positive length. 058 * <p> 059 * <ul> 060 * <li>returns <code>true</code> iff the parameters designate a subarray of 061 * positive length</li> 062 * <li>throws <code>IllegalArgumentException</code> if the array is null or 063 * or the indices are invalid</li> 064 * <li>returns <code>false</li> if the array is non-null, but 065 * <code>length</code> is 0. 066 * </ul></p> 067 * 068 * @param values the input array 069 * @param begin index of the first array element to include 070 * @param length the number of elements to include 071 * @return true if the parameters are valid and designate a subarray of positive length 072 * @throws IllegalArgumentException if the indices are invalid or the array is null 073 */ 074 protected boolean test( 075 final double[] values, 076 final int begin, 077 final int length) { 078 079 if (values == null) { 080 throw MathRuntimeException.createIllegalArgumentException("input values array is null"); 081 } 082 083 if (begin < 0) { 084 throw MathRuntimeException.createIllegalArgumentException( 085 "start position cannot be negative ({0})", begin); 086 } 087 088 if (length < 0) { 089 throw MathRuntimeException.createIllegalArgumentException( 090 "length cannot be negative ({0})", length); 091 } 092 093 if (begin + length > values.length) { 094 throw MathRuntimeException.createIllegalArgumentException( 095 "subarray ends after array end"); 096 } 097 098 if (length == 0) { 099 return false; 100 } 101 102 return true; 103 104 } 105 106 /** 107 * This method is used by <code>evaluate(double[], double[], int, int)</code> methods 108 * to verify that the begin and length parameters designate a subarray of positive length 109 * and the weights are all non-negative, non-NaN, finite, and not all zero. 110 * <p> 111 * <ul> 112 * <li>returns <code>true</code> iff the parameters designate a subarray of 113 * positive length and the weights array contains legitimate values.</li> 114 * <li>throws <code>IllegalArgumentException</code> if any of the following are true: 115 * <ul><li>the values array is null</li> 116 * <li>the weights array is null</li> 117 * <li>the weights array does not have the same length as the values array</li> 118 * <li>the weights array contains one or more infinite values</li> 119 * <li>the weights array contains one or more NaN values</li> 120 * <li>the weights array contains negative values</li> 121 * <li>the start and length arguments do not determine a valid array</li></ul> 122 * </li> 123 * <li>returns <code>false</li> if the array is non-null, but 124 * <code>length</code> is 0. 125 * </ul></p> 126 * 127 * @param values the input array 128 * @param weights the weights array 129 * @param begin index of the first array element to include 130 * @param length the number of elements to include 131 * @return true if the parameters are valid and designate a subarray of positive length 132 * @throws IllegalArgumentException if the indices are invalid or the array is null 133 * @since 2.1 134 */ 135 protected boolean test( 136 final double[] values, 137 final double[] weights, 138 final int begin, 139 final int length) { 140 141 if (weights == null) { 142 throw MathRuntimeException.createIllegalArgumentException("input weights array is null"); 143 } 144 145 if (weights.length != values.length) { 146 throw MathRuntimeException.createIllegalArgumentException( 147 "Different number of weights and values"); 148 } 149 150 boolean containsPositiveWeight = false; 151 for (int i = begin; i < begin + length; i++) { 152 if (Double.isNaN(weights[i])) { 153 throw MathRuntimeException.createIllegalArgumentException( 154 "NaN weight at index {0}", i); 155 } 156 if (Double.isInfinite(weights[i])) { 157 throw MathRuntimeException.createIllegalArgumentException( 158 "Infinite weight at index {0}", i); 159 } 160 if (weights[i] < 0) { 161 throw MathRuntimeException.createIllegalArgumentException( 162 "negative weight {0} at index {1} ", weights[i], i); 163 } 164 if (!containsPositiveWeight && weights[i] > 0.0) { 165 containsPositiveWeight = true; 166 } 167 } 168 169 if (!containsPositiveWeight) { 170 throw MathRuntimeException.createIllegalArgumentException( 171 "weight array must contain at least one non-zero value"); 172 } 173 174 return test(values, begin, length); 175 } 176 } 177