1 /* 2 * Copyright 2003-2004 The Apache Software Foundation. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 package org.apache.commons.math.stat.descriptive; 17 18 /** 19 * Extends the definition of {@link UnivariateStatistic} with 20 * {@link #increment} and {@link #incrementAll(double[])} methods for adding 21 * values and updating internal state. 22 * <p> 23 * This interface is designed to be used for calculating statistics that can be computed in 24 * one pass through the data without storing the full array of sample values. 25 * 26 * @version $Revision: 155427 $ $Date: 2005-02-26 06:11:52 -0700 (Sat, 26 Feb 2005) $ 27 */ 28 public interface StorelessUnivariateStatistic extends UnivariateStatistic { 29 30 /** 31 * Updates the internal state of the statistic to reflect the addition of the new value. 32 * @param d the new value. 33 */ 34 void increment(double d); 35 36 /** 37 * Updates the internal state of the statistic to reflect addition of 38 * all values in the values array. Does not clear the statistic first -- 39 * i.e., the values are added <strong>incrementally</stong> to the dataset. 40 * 41 * @param values array holding the new values to add 42 * @throws IllegalArgumentException if the array is null 43 */ 44 void incrementAll(double[] values); 45 46 /** 47 * Updates the internal state of the statistic to reflect addition of 48 * the values in the designated portion of the values array. Does not 49 * clear the statistic first -- i.e., the values are added 50 * <strong>incrementally</stong> to the dataset. 51 * 52 * @param values array holding the new values to add 53 * @param start the array index of the first value to add 54 * @param length the number of elements to add 55 * @throws IllegalArgumentException if the array is null or the index 56 */ 57 void incrementAll(double[] values, int start, int length); 58 59 /** 60 * Returns the current value of the Statistic. 61 * @return value of the statistic, <code>Double.NaN</code> if it 62 * has been cleared or just instantiated. 63 */ 64 double getResult(); 65 66 /** 67 * Returns the number of values that have been added. 68 * @return the number of values. 69 */ 70 long getN(); 71 72 /** 73 * Clears the internal state of the Statistic 74 */ 75 void clear(); 76 77 }