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24
25#ifndef SHARE_UTILITIES_NUMBERSEQ_HPP
26#define SHARE_UTILITIES_NUMBERSEQ_HPP
27
28#include "memory/allocation.hpp"
29
30/**
31 ** This file contains a few classes that represent number sequence,
32 ** x1, x2, x3, ..., xN, and can calculate their avg, max, and sd.
33 **
34 ** Here's a quick description of the classes:
35 **
36 ** AbsSeq: abstract superclass
37 ** NumberSeq: the sequence is assumed to be very long and the
38 ** maximum, avg, sd, davg, and dsd are calculated over all its elements
39 ** TruncatedSeq: this class keeps track of the last L elements
40 ** of the sequence and calculates avg, max, and sd only over them
41 **/
42
43#define DEFAULT_ALPHA_VALUE 0.7
44
45class AbsSeq: public CHeapObj<mtInternal> {
46private:
47 void init(double alpha);
48
49protected:
50 int _num; // the number of elements in the sequence
51 double _sum; // the sum of the elements in the sequence
52 double _sum_of_squares; // the sum of squares of the elements in the sequence
53
54 double _davg; // decaying average
55 double _dvariance; // decaying variance
56 double _alpha; // factor for the decaying average / variance
57
58 // This is what we divide with to get the average. In a standard
59 // number sequence, this should just be the number of elements in it.
60 virtual double total() const { return (double) _num; };
61
62public:
63 AbsSeq(double alpha = DEFAULT_ALPHA_VALUE);
64
65 virtual void add(double val); // adds a new element to the sequence
66 void add(unsigned val) { add((double) val); }
67 virtual double maximum() const = 0; // maximum element in the sequence
68 virtual double last() const = 0; // last element added in the sequence
69
70 // the number of elements in the sequence
71 int num() const { return _num; }
72 // the sum of the elements in the sequence
73 double sum() const { return _sum; }
74
75 double avg() const; // the average of the sequence
76 double variance() const; // the variance of the sequence
77 double sd() const; // the standard deviation of the sequence
78
79 double davg() const; // decaying average
80 double dvariance() const; // decaying variance
81 double dsd() const; // decaying "standard deviation"
82
83 // Debugging/Printing
84 virtual void dump();
85 virtual void dump_on(outputStream* s);
86};
87
88class NumberSeq: public AbsSeq {
89private:
90 bool check_nums(NumberSeq* total, int n, NumberSeq** parts);
91
92protected:
93 double _last;
94 double _maximum; // keep track of maximum value
95
96public:
97 NumberSeq(double alpha = DEFAULT_ALPHA_VALUE);
98
99 virtual void add(double val);
100 virtual double maximum() const { return _maximum; }
101 virtual double last() const { return _last; }
102
103 // Debugging/Printing
104 virtual void dump_on(outputStream* s);
105};
106
107class TruncatedSeq: public AbsSeq {
108private:
109 enum PrivateConstants {
110 DefaultSeqLength = 10
111 };
112 void init();
113protected:
114 double *_sequence; // buffers the last L elements in the sequence
115 int _length; // this is L
116 int _next; // oldest slot in the array, i.e. next to be overwritten
117
118public:
119 // accepts a value for L
120 TruncatedSeq(int length = DefaultSeqLength,
121 double alpha = DEFAULT_ALPHA_VALUE);
122 ~TruncatedSeq();
123 virtual void add(double val);
124 virtual double maximum() const;
125 virtual double last() const; // the last value added to the sequence
126
127 double oldest() const; // the oldest valid value in the sequence
128 double predict_next() const; // prediction based on linear regression
129
130 // Debugging/Printing
131 virtual void dump_on(outputStream* s);
132};
133
134#endif // SHARE_UTILITIES_NUMBERSEQ_HPP
135