Mercurial Hosting > luan

annotate src/org/eclipse/jetty/util/statistic/SampleStatistic.java @ 802:3428c60d7cfc

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
replace jetty jars with source
author Franklin Schmidt <fschmidt@gmail.com>
date Wed, 07 Sep 2016 21:15:48 -0600
parents
children
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
802
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
1 //
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
2 // ========================================================================
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
3 // Copyright (c) 1995-2014 Mort Bay Consulting Pty. Ltd.
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
4 // ------------------------------------------------------------------------
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
5 // All rights reserved. This program and the accompanying materials
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
6 // are made available under the terms of the Eclipse Public License v1.0
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
7 // and Apache License v2.0 which accompanies this distribution.
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
8 //
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
9 // The Eclipse Public License is available at
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
10 // http://www.eclipse.org/legal/epl-v10.html
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
11 //
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
12 // The Apache License v2.0 is available at
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
13 // http://www.opensource.org/licenses/apache2.0.php
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
14 //
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
15 // You may elect to redistribute this code under either of these licenses.
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
16 // ========================================================================
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
17 //
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
18
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
19 package org.eclipse.jetty.util.statistic;
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
20
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
21 import java.util.concurrent.atomic.AtomicLong;
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
22
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
23 import org.eclipse.jetty.util.Atomics;
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
24
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
25
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
26 /* ------------------------------------------------------------ */
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
27 /**
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
28 * SampledStatistics
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
29 * <p>
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
30 * Provides max, total, mean, count, variance, and standard
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
31 * deviation of continuous sequence of samples.
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
32 * <p>
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
33 * Calculates estimates of mean, variance, and standard deviation
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
34 * characteristics of a sample using a non synchronized
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
35 * approximation of the on-line algorithm presented
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
36 * in Donald Knuth's Art of Computer Programming, Volume 2,
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
37 * Seminumerical Algorithms, 3rd edition, page 232,
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
38 * Boston: Addison-Wesley. that cites a 1962 paper by B.P. Welford
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
39 * that can be found by following the link http://www.jstor.org/pss/1266577
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
40 * <p>
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
41 * This algorithm is also described in Wikipedia at
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
42 * http://en.wikipedia.org/w/index.php?title=Algorithms_for_calculating_variance&section=4#On-line_algorithm
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
43 */
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
44 public class SampleStatistic
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
45 {
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
46 protected final AtomicLong _max = new AtomicLong();
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
47 protected final AtomicLong _total = new AtomicLong();
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
48 protected final AtomicLong _count = new AtomicLong();
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
49 protected final AtomicLong _totalVariance100 = new AtomicLong();
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
50
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
51 public void reset()
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
52 {
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
53 _max.set(0);
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
54 _total.set(0);
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
55 _count.set(0);
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
56 _totalVariance100.set(0);
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
57 }
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
58
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
59 public void set(final long sample)
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
60 {
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
61 long total = _total.addAndGet(sample);
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
62 long count = _count.incrementAndGet();
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
63
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
64 if (count>1)
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
65 {
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
66 long mean10 = total*10/count;
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
67 long delta10 = sample*10 - mean10;
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
68 _totalVariance100.addAndGet(delta10*delta10);
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
69 }
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
70
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
71 Atomics.updateMax(_max, sample);
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
72 }
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
73
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
74 /**
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
75 * @return the max value
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
76 */
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
77 public long getMax()
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
78 {
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
79 return _max.get();
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
80 }
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
81
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
82 public long getTotal()
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
83 {
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
84 return _total.get();
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
85 }
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
86
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
87 public long getCount()
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
88 {
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
89 return _count.get();
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
90 }
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
91
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
92 public double getMean()
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
93 {
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
94 return (double)_total.get()/_count.get();
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
95 }
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
96
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
97 public double getVariance()
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
98 {
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
99 final long variance100 = _totalVariance100.get();
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
100 final long count = _count.get();
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
101
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
102 return count>1?((double)variance100)/100.0/(count-1):0.0;
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
103 }
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
104
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
105 public double getStdDev()
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
106 {
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
107 return Math.sqrt(getVariance());
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
108 }
3428c60d7cfc replace jetty jars with source
Franklin Schmidt <fschmidt@gmail.com>
parents:
diff changeset
109 }