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 /** 020 * Extends the definition of {@link UnivariateStatistic} with 021 * {@link #increment} and {@link #incrementAll(double[])} methods for adding 022 * values and updating internal state. 023 * <p> 024 * This interface is designed to be used for calculating statistics that can be 025 * computed in one pass through the data without storing the full array of 026 * sample values.</p> 027 * 028 * @version $Revision: 811685 $ $Date: 2009-09-05 19:36:48 +0200 (sam. 05 sept. 2009) $ 029 */ 030 public interface StorelessUnivariateStatistic extends UnivariateStatistic { 031 032 /** 033 * Updates the internal state of the statistic to reflect the addition of the new value. 034 * @param d the new value. 035 */ 036 void increment(double d); 037 038 /** 039 * Updates the internal state of the statistic to reflect addition of 040 * all values in the values array. Does not clear the statistic first -- 041 * i.e., the values are added <strong>incrementally</strong> to the dataset. 042 * 043 * @param values array holding the new values to add 044 * @throws IllegalArgumentException if the array is null 045 */ 046 void incrementAll(double[] values); 047 048 /** 049 * Updates the internal state of the statistic to reflect addition of 050 * the values in the designated portion of the values array. Does not 051 * clear the statistic first -- i.e., the values are added 052 * <strong>incrementally</strong> to the dataset. 053 * 054 * @param values array holding the new values to add 055 * @param start the array index of the first value to add 056 * @param length the number of elements to add 057 * @throws IllegalArgumentException if the array is null or the index 058 */ 059 void incrementAll(double[] values, int start, int length); 060 061 /** 062 * Returns the current value of the Statistic. 063 * @return value of the statistic, <code>Double.NaN</code> if it 064 * has been cleared or just instantiated. 065 */ 066 double getResult(); 067 068 /** 069 * Returns the number of values that have been added. 070 * @return the number of values. 071 */ 072 long getN(); 073 074 /** 075 * Clears the internal state of the Statistic 076 */ 077 void clear(); 078 079 /** 080 * Returns a copy of the statistic with the same internal state. 081 * 082 * @return a copy of the statistic 083 */ 084 StorelessUnivariateStatistic copy(); 085 086 }