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 */ 017package org.apache.commons.math4.legacy.stat.descriptive; 018 019import org.apache.commons.math4.legacy.exception.MathIllegalArgumentException; 020import org.apache.commons.math4.legacy.exception.NullArgumentException; 021import org.apache.commons.math4.legacy.exception.util.LocalizedFormats; 022import org.apache.commons.math4.legacy.core.MathArrays; 023import org.apache.commons.numbers.core.Precision; 024 025/** 026 * Abstract base class for implementations of the 027 * {@link StorelessUnivariateStatistic} interface. 028 * <p> 029 * Provides default {@code evaluate(double[],...)} and {@code incrementAll(double[])} 030 * implementations. 031 * <p> 032 * <strong>Note that these implementations are not synchronized.</strong> 033 */ 034public abstract class AbstractStorelessUnivariateStatistic 035 implements StorelessUnivariateStatistic { 036 037 /** 038 * This default implementation creates a copy of this {@link StorelessUnivariateStatistic} 039 * instance, calls {@link #clear} on it, then calls {@link #incrementAll} with the specified 040 * portion of the input array, and then uses {@link #getResult} to compute the return value. 041 * <p> 042 * Note that this implementation does not change the internal state of the statistic. 043 * <p> 044 * Implementations may override this method with a more efficient and possibly more 045 * accurate implementation that works directly with the input array. 046 * <p> 047 * If the array is null, a MathIllegalArgumentException is thrown. 048 * 049 * @param values input array 050 * @return the value of the statistic applied to the input array 051 * @throws MathIllegalArgumentException if values is null 052 * @see org.apache.commons.math4.legacy.stat.descriptive.UnivariateStatistic#evaluate(double[]) 053 */ 054 @Override 055 public double evaluate(final double[] values) throws MathIllegalArgumentException { 056 if (values == null) { 057 throw new NullArgumentException(LocalizedFormats.INPUT_ARRAY); 058 } 059 return evaluate(values, 0, values.length); 060 } 061 062 /** 063 * This default implementation creates a copy of this {@link StorelessUnivariateStatistic} 064 * instance, calls {@link #clear} on it, then calls {@link #incrementAll} with the specified 065 * portion of the input array, and then uses {@link #getResult} to compute the return value. 066 * <p> 067 * Note that this implementation does not change the internal state of the statistic. 068 * <p> 069 * Implementations may override this method with a more efficient and possibly more 070 * accurate implementation that works directly with the input array. 071 * <p> 072 * If the array is null or the index parameters are not valid, an 073 * MathIllegalArgumentException is thrown. 074 * 075 * @param values the input array 076 * @param begin the index of the first element to include 077 * @param length the number of elements to include 078 * @return the value of the statistic applied to the included array entries 079 * @throws MathIllegalArgumentException if the array is null or the indices are not valid 080 * @see org.apache.commons.math4.legacy.stat.descriptive.UnivariateStatistic#evaluate(double[], int, int) 081 */ 082 @Override 083 public double evaluate(final double[] values, final int begin, final int length) 084 throws MathIllegalArgumentException { 085 086 if (MathArrays.verifyValues(values, begin, length)) { 087 final StorelessUnivariateStatistic stat = copy(); 088 stat.clear(); 089 stat.incrementAll(values, begin, length); 090 return stat.getResult(); 091 } 092 return Double.NaN; 093 } 094 095 /** 096 * {@inheritDoc} 097 */ 098 @Override 099 public abstract StorelessUnivariateStatistic copy(); 100 101 /** 102 * {@inheritDoc} 103 */ 104 @Override 105 public abstract void clear(); 106 107 /** 108 * {@inheritDoc} 109 */ 110 @Override 111 public abstract double getResult(); 112 113 /** 114 * {@inheritDoc} 115 */ 116 @Override 117 public abstract void increment(double d); 118 119 /** 120 * This default implementation just calls {@link #increment} in a loop over 121 * the input array. 122 * <p> 123 * Throws IllegalArgumentException if the input values array is null. 124 * 125 * @param values values to add 126 * @throws MathIllegalArgumentException if values is null 127 * @see StorelessUnivariateStatistic#incrementAll(double[]) 128 */ 129 @Override 130 public void incrementAll(double[] values) throws MathIllegalArgumentException { 131 if (values == null) { 132 throw new NullArgumentException(LocalizedFormats.INPUT_ARRAY); 133 } 134 incrementAll(values, 0, values.length); 135 } 136 137 /** 138 * This default implementation just calls {@link #increment} in a loop over 139 * the specified portion of the input array. 140 * <p> 141 * Throws IllegalArgumentException if the input values array is null. 142 * 143 * @param values array holding values to add 144 * @param begin index of the first array element to add 145 * @param length number of array elements to add 146 * @throws MathIllegalArgumentException if values is null 147 * @see StorelessUnivariateStatistic#incrementAll(double[], int, int) 148 */ 149 @Override 150 public void incrementAll(double[] values, int begin, int length) throws MathIllegalArgumentException { 151 if (MathArrays.verifyValues(values, begin, length)) { 152 int k = begin + length; 153 for (int i = begin; i < k; i++) { 154 increment(values[i]); 155 } 156 } 157 } 158 159 /** 160 * Returns true iff <code>object</code> is the same type of 161 * {@link StorelessUnivariateStatistic} (the object's class equals this 162 * instance) returning the same values as this for <code>getResult()</code> 163 * and <code>getN()</code>. 164 * 165 * @param object object to test equality against. 166 * @return true if object returns the same value as this 167 */ 168 @Override 169 public boolean equals(Object object) { 170 if (object == this ) { 171 return true; 172 } 173 if (object == null || object.getClass() != this.getClass()) { 174 return false; 175 } 176 StorelessUnivariateStatistic stat = (StorelessUnivariateStatistic) object; 177 return Precision.equalsIncludingNaN(stat.getResult(), this.getResult()) && 178 Precision.equalsIncludingNaN(stat.getN(), this.getN()); 179 } 180 181 /** 182 * Returns hash code based on getResult() and getN(). 183 * 184 * @return hash code 185 */ 186 @Override 187 public int hashCode() { 188 return 31 * (31 + Double.hashCode(getResult())) + Double.hashCode(getN()); 189 } 190}