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 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
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 * See the License for the specific language governing permissions and
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package org.apache.commons.math3.stat.descriptive;

import org.apache.commons.math3.exception.MathIllegalArgumentException;

Extends the definition of UnivariateStatistic with increment and incrementAll(double[]) methods for adding values and updating internal state. 

This interface is designed to be used for calculating statistics that can be
computed in one pass through the data without storing the full array of
sample values.
/**
 * Extends the definition of {@link UnivariateStatistic} with
 * {@link #increment} and {@link #incrementAll(double[])} methods for adding
 * values and updating internal state.
 * <p>
 * This interface is designed to be used for calculating statistics that can be
 * computed in one pass through the data without storing the full array of
 * sample values.</p>
 *
 */
public interface StorelessUnivariateStatistic extends UnivariateStatistic {

    
Updates the internal state of the statistic to reflect the addition of the new value.
Params:
d –  the new value./**
     * Updates the internal state of the statistic to reflect the addition of the new value.
     * @param d  the new value.
     */
    void increment(double d);

    
Updates the internal state of the statistic to reflect addition of
all values in the values array.  Does not clear the statistic first --
i.e., the values are added incrementally to the dataset.
Params:
values –  array holding the new values to add
Throws:
MathIllegalArgumentException – if the array is null/**
     * Updates the internal state of the statistic to reflect addition of
     * all values in the values array.  Does not clear the statistic first --
     * i.e., the values are added <strong>incrementally</strong> to the dataset.
     *
     * @param values  array holding the new values to add
     * @throws MathIllegalArgumentException if the array is null
     */
    void incrementAll(double[] values) throws MathIllegalArgumentException;

    
Updates the internal state of the statistic to reflect addition of
the values in the designated portion of the values array.  Does not
clear the statistic first -- i.e., the values are added
incrementally to the dataset.
Params:
values –  array holding the new values to add
start –  the array index of the first value to add
length –  the number of elements to add
Throws:
MathIllegalArgumentException – if the array is null or the index/**
     * Updates the internal state of the statistic to reflect addition of
     * the values in the designated portion of the values array.  Does not
     * clear the statistic first -- i.e., the values are added
     * <strong>incrementally</strong> to the dataset.
     *
     * @param values  array holding the new values to add
     * @param start  the array index of the first value to add
     * @param length  the number of elements to add
     * @throws MathIllegalArgumentException if the array is null or the index
     */
    void incrementAll(double[] values, int start, int length) throws MathIllegalArgumentException;

    
Returns the current value of the Statistic.
Returns:
value of the statistic, Double.NaN if it
has been cleared or just instantiated./**
     * Returns the current value of the Statistic.
     * @return value of the statistic, <code>Double.NaN</code> if it
     * has been cleared or just instantiated.
     */
    double getResult();

    
Returns the number of values that have been added.
Returns:
the number of values./**
     * Returns the number of values that have been added.
     * @return the number of values.
     */
    long getN();

    
Clears the internal state of the Statistic
/**
     * Clears the internal state of the Statistic
     */
    void clear();

    
Returns a copy of the statistic with the same internal state.
Returns:
a copy of the statistic/**
     * Returns a copy of the statistic with the same internal state.
     *
     * @return a copy of the statistic
     */
    StorelessUnivariateStatistic copy();

}