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.math3.stat.descriptive; 018 019 import org.apache.commons.math3.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.</p> 029 * 030 * @version $Id: StorelessUnivariateStatistic.java 1416643 2012-12-03 19:37:14Z tn $ 031 */ 032 public interface StorelessUnivariateStatistic extends UnivariateStatistic { 033 034 /** 035 * Updates the internal state of the statistic to reflect the addition of the new value. 036 * @param d the new value. 037 */ 038 void increment(double d); 039 040 /** 041 * Updates the internal state of the statistic to reflect addition of 042 * all values in the values array. Does not clear the statistic first -- 043 * i.e., the values are added <strong>incrementally</strong> to the dataset. 044 * 045 * @param values array holding the new values to add 046 * @throws MathIllegalArgumentException if the array is null 047 */ 048 void incrementAll(double[] values) throws MathIllegalArgumentException; 049 050 /** 051 * Updates the internal state of the statistic to reflect addition of 052 * the values in the designated portion of the values array. Does not 053 * clear the statistic first -- i.e., the values are added 054 * <strong>incrementally</strong> to the dataset. 055 * 056 * @param values array holding the new values to add 057 * @param start the array index of the first value to add 058 * @param length the number of elements to add 059 * @throws MathIllegalArgumentException if the array is null or the index 060 */ 061 void incrementAll(double[] values, int start, int length) throws MathIllegalArgumentException; 062 063 /** 064 * Returns the current value of the Statistic. 065 * @return value of the statistic, <code>Double.NaN</code> if it 066 * has been cleared or just instantiated. 067 */ 068 double getResult(); 069 070 /** 071 * Returns the number of values that have been added. 072 * @return the number of values. 073 */ 074 long getN(); 075 076 /** 077 * Clears the internal state of the Statistic 078 */ 079 void clear(); 080 081 /** 082 * Returns a copy of the statistic with the same internal state. 083 * 084 * @return a copy of the statistic 085 */ 086 StorelessUnivariateStatistic copy(); 087 088 }