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 }