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; 020 021/** 022 * Extends the definition of {@link UnivariateStatistic} with 023 * {@link #increment} and {@link #incrementAll(double[])} methods for adding 024 * values and updating internal state. 025 * <p> 026 * This interface is designed to be used for calculating statistics that can be 027 * computed in one pass through the data without storing the full array of 028 * sample values. 029 * <p> 030 * Note: unless otherwise stated, the {@link #evaluate(double[])} and 031 * {@link #evaluate(double[], int, int)} methods do <b>NOT</b> alter the internal 032 * state of the respective statistic. 033 */ 034public interface StorelessUnivariateStatistic extends UnivariateStatistic { 035 036 /** 037 * Updates the internal state of the statistic to reflect the addition of the new value. 038 * @param d the new value. 039 */ 040 void increment(double d); 041 042 /** 043 * Updates the internal state of the statistic to reflect addition of 044 * all values in the values array. Does not clear the statistic first -- 045 * i.e., the values are added <strong>incrementally</strong> to the dataset. 046 * 047 * @param values array holding the new values to add 048 * @throws MathIllegalArgumentException if the array is null 049 */ 050 void incrementAll(double[] values) throws MathIllegalArgumentException; 051 052 /** 053 * Updates the internal state of the statistic to reflect addition of 054 * the values in the designated portion of the values array. Does not 055 * clear the statistic first -- i.e., the values are added 056 * <strong>incrementally</strong> to the dataset. 057 * 058 * @param values array holding the new values to add 059 * @param start the array index of the first value to add 060 * @param length the number of elements to add 061 * @throws MathIllegalArgumentException if the array is null or the index 062 */ 063 void incrementAll(double[] values, int start, int length) throws MathIllegalArgumentException; 064 065 /** 066 * Returns the current value of the Statistic. 067 * @return value of the statistic, <code>Double.NaN</code> if it 068 * has been cleared or just instantiated. 069 */ 070 double getResult(); 071 072 /** 073 * Returns the number of values that have been added. 074 * @return the number of values. 075 */ 076 long getN(); 077 078 /** 079 * Clears the internal state of the Statistic. 080 */ 081 void clear(); 082 083 /** 084 * Returns a copy of the statistic with the same internal state. 085 * 086 * @return a copy of the statistic 087 */ 088 @Override 089 StorelessUnivariateStatistic copy(); 090}