1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.math.stat.descriptive;
18
19 /**
20 * Extends the definition of {@link UnivariateStatistic} with
21 * {@link #increment} and {@link #incrementAll(double[])} methods for adding
22 * values and updating internal state.
23 * <p>
24 * This interface is designed to be used for calculating statistics that can be
25 * computed in one pass through the data without storing the full array of
26 * sample values.</p>
27 *
28 * @version $Revision: 617953 $ $Date: 2008-02-02 22:54:00 -0700 (Sat, 02 Feb 2008) $
29 */
30 public interface StorelessUnivariateStatistic extends UnivariateStatistic {
31
32 /**
33 * Updates the internal state of the statistic to reflect the addition of the new value.
34 * @param d the new value.
35 */
36 void increment(double d);
37
38 /**
39 * Updates the internal state of the statistic to reflect addition of
40 * all values in the values array. Does not clear the statistic first --
41 * i.e., the values are added <strong>incrementally</stong> to the dataset.
42 *
43 * @param values array holding the new values to add
44 * @throws IllegalArgumentException if the array is null
45 */
46 void incrementAll(double[] values);
47
48 /**
49 * Updates the internal state of the statistic to reflect addition of
50 * the values in the designated portion of the values array. Does not
51 * clear the statistic first -- i.e., the values are added
52 * <strong>incrementally</stong> to the dataset.
53 *
54 * @param values array holding the new values to add
55 * @param start the array index of the first value to add
56 * @param length the number of elements to add
57 * @throws IllegalArgumentException if the array is null or the index
58 */
59 void incrementAll(double[] values, int start, int length);
60
61 /**
62 * Returns the current value of the Statistic.
63 * @return value of the statistic, <code>Double.NaN</code> if it
64 * has been cleared or just instantiated.
65 */
66 double getResult();
67
68 /**
69 * Returns the number of values that have been added.
70 * @return the number of values.
71 */
72 long getN();
73
74 /**
75 * Clears the internal state of the Statistic
76 */
77 void clear();
78
79 }