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comparison src/share/vm/utilities/numberSeq.hpp @ 342:37f87013dfd8

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6711316: Open source the Garbage-First garbage collector Summary: First mercurial integration of the code for the Garbage-First garbage collector. Reviewed-by: apetrusenko, iveresov, jmasa, sgoldman, tonyp, ysr
author ysr
date Thu, 05 Jun 2008 15:57:56 -0700
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children 89f1b9ae8991
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189:0b27f3512f9e 342:37f87013dfd8
1 /*
2 * Copyright 2001-2007 Sun Microsystems, Inc. All Rights Reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25 /**
26 ** This file contains a few classes that represent number sequence,
27 ** x1, x2, x3, ..., xN, and can calculate their avg, max, and sd.
28 **
29 ** Here's a quick description of the classes:
30 **
31 ** AbsSeq: abstract superclass
32 ** NumberSeq: the sequence is assumed to be very long and the
33 ** maximum, avg, sd, davg, and dsd are calculated over all its elements
34 ** TruncatedSeq: this class keeps track of the last L elements
35 ** of the sequence and calculates avg, max, and sd only over them
36 **/
37
38 #define DEFAULT_ALPHA_VALUE 0.7
39
40 class AbsSeq {
41 private:
42 void init(double alpha);
43
44 protected:
45 int _num; // the number of elements in the sequence
46 double _sum; // the sum of the elements in the sequence
47 double _sum_of_squares; // the sum of squares of the elements in the sequence
48
49 double _davg; // decaying average
50 double _dvariance; // decaying variance
51 double _alpha; // factor for the decaying average / variance
52
53 // This is what we divide with to get the average. In a standard
54 // number sequence, this should just be the number of elements in it.
55 virtual double total() const { return (double) _num; };
56
57 public:
58 AbsSeq(double alpha = DEFAULT_ALPHA_VALUE);
59
60 virtual void add(double val); // adds a new element to the sequence
61 void add(unsigned val) { add((double) val); }
62 virtual double maximum() const = 0; // maximum element in the sequence
63 virtual double last() const = 0; // last element added in the sequence
64
65 // the number of elements in the sequence
66 int num() const { return _num; }
67 // the sum of the elements in the sequence
68 double sum() const { return _sum; }
69
70 double avg() const; // the average of the sequence
71 double variance() const; // the variance of the sequence
72 double sd() const; // the standard deviation of the sequence
73
74 double davg() const; // decaying average
75 double dvariance() const; // decaying variance
76 double dsd() const; // decaying "standard deviation"
77 };
78
79 class NumberSeq: public AbsSeq {
80 private:
81 bool check_nums(NumberSeq* total, int n, NumberSeq** parts);
82
83 protected:
84 double _last;
85 double _maximum; // keep track of maximum value
86
87 public:
88 NumberSeq(double alpha = DEFAULT_ALPHA_VALUE);
89 NumberSeq(NumberSeq* total, int n_parts, NumberSeq** parts);
90
91 virtual void add(double val);
92 virtual double maximum() const { return _maximum; }
93 virtual double last() const { return _last; }
94 };
95
96 class TruncatedSeq: public AbsSeq {
97 private:
98 enum PrivateConstants {
99 DefaultSeqLength = 10
100 };
101 void init();
102 protected:
103 double *_sequence; // buffers the last L elements in the sequence
104 int _length; // this is L
105 int _next; // oldest slot in the array, i.e. next to be overwritten
106
107 public:
108 // accepts a value for L
109 TruncatedSeq(int length = DefaultSeqLength,
110 double alpha = DEFAULT_ALPHA_VALUE);
111 virtual void add(double val);
112 virtual double maximum() const;
113 virtual double last() const; // the last value added to the sequence
114
115 double oldest() const; // the oldest valid value in the sequence
116 double predict_next() const; // prediction based on linear regression
117 };