1 /* 2 * Copyright (c) 2001, 2019, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 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 0.3 44 45 class AbsSeq: public CHeapObj<mtInternal> { 46 private: 47 void init(double alpha); 48 49 protected: 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. total() const60 virtual double total() const { return (double) _num; }; 61 62 public: 63 AbsSeq(double alpha = DEFAULT_ALPHA_VALUE); 64 65 virtual void add(double val); // adds a new element to the sequence add(unsigned val)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 num() const71 int num() const { return _num; } 72 // the sum of the elements in the sequence sum() const73 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 88 class NumberSeq: public AbsSeq { 89 private: 90 bool check_nums(NumberSeq* total, int n, NumberSeq** parts); 91 92 protected: 93 double _last; 94 double _maximum; // keep track of maximum value 95 96 public: 97 NumberSeq(double alpha = DEFAULT_ALPHA_VALUE); 98 99 virtual void add(double val); maximum() const100 virtual double maximum() const { return _maximum; } last() const101 virtual double last() const { return _last; } 102 103 // Debugging/Printing 104 virtual void dump_on(outputStream* s); 105 }; 106 107 class TruncatedSeq: public AbsSeq { 108 private: 109 enum PrivateConstants { 110 DefaultSeqLength = 10 111 }; 112 void init(); 113 protected: 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 117 118 public: 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