| /* |
| * Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
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| */ |
| |
| #ifndef SHARE_VM_UTILITIES_NUMBERSEQ_HPP |
| #define SHARE_VM_UTILITIES_NUMBERSEQ_HPP |
| |
| #include "memory/allocation.hpp" |
| |
| /** |
| ** This file contains a few classes that represent number sequence, |
| ** x1, x2, x3, ..., xN, and can calculate their avg, max, and sd. |
| ** |
| ** Here's a quick description of the classes: |
| ** |
| ** AbsSeq: abstract superclass |
| ** NumberSeq: the sequence is assumed to be very long and the |
| ** maximum, avg, sd, davg, and dsd are calculated over all its elements |
| ** TruncatedSeq: this class keeps track of the last L elements |
| ** of the sequence and calculates avg, max, and sd only over them |
| **/ |
| |
| #define DEFAULT_ALPHA_VALUE 0.7 |
| |
| class AbsSeq: public CHeapObj<mtInternal> { |
| private: |
| void init(double alpha); |
| |
| protected: |
| int _num; // the number of elements in the sequence |
| double _sum; // the sum of the elements in the sequence |
| double _sum_of_squares; // the sum of squares of the elements in the sequence |
| |
| double _davg; // decaying average |
| double _dvariance; // decaying variance |
| double _alpha; // factor for the decaying average / variance |
| |
| // This is what we divide with to get the average. In a standard |
| // number sequence, this should just be the number of elements in it. |
| virtual double total() const { return (double) _num; }; |
| |
| public: |
| AbsSeq(double alpha = DEFAULT_ALPHA_VALUE); |
| |
| virtual void add(double val); // adds a new element to the sequence |
| void add(unsigned val) { add((double) val); } |
| virtual double maximum() const = 0; // maximum element in the sequence |
| virtual double last() const = 0; // last element added in the sequence |
| |
| // the number of elements in the sequence |
| int num() const { return _num; } |
| // the sum of the elements in the sequence |
| double sum() const { return _sum; } |
| |
| double avg() const; // the average of the sequence |
| double variance() const; // the variance of the sequence |
| double sd() const; // the standard deviation of the sequence |
| |
| double davg() const; // decaying average |
| double dvariance() const; // decaying variance |
| double dsd() const; // decaying "standard deviation" |
| |
| // Debugging/Printing |
| virtual void dump(); |
| virtual void dump_on(outputStream* s); |
| }; |
| |
| class NumberSeq: public AbsSeq { |
| private: |
| bool check_nums(NumberSeq* total, int n, NumberSeq** parts); |
| |
| protected: |
| double _last; |
| double _maximum; // keep track of maximum value |
| |
| public: |
| NumberSeq(double alpha = DEFAULT_ALPHA_VALUE); |
| |
| virtual void add(double val); |
| virtual double maximum() const { return _maximum; } |
| virtual double last() const { return _last; } |
| |
| // Debugging/Printing |
| virtual void dump_on(outputStream* s); |
| }; |
| |
| class TruncatedSeq: public AbsSeq { |
| private: |
| enum PrivateConstants { |
| DefaultSeqLength = 10 |
| }; |
| void init(); |
| protected: |
| double *_sequence; // buffers the last L elements in the sequence |
| int _length; // this is L |
| int _next; // oldest slot in the array, i.e. next to be overwritten |
| |
| public: |
| // accepts a value for L |
| TruncatedSeq(int length = DefaultSeqLength, |
| double alpha = DEFAULT_ALPHA_VALUE); |
| ~TruncatedSeq(); |
| virtual void add(double val); |
| virtual double maximum() const; |
| virtual double last() const; // the last value added to the sequence |
| |
| double oldest() const; // the oldest valid value in the sequence |
| double predict_next() const; // prediction based on linear regression |
| |
| // Debugging/Printing |
| virtual void dump_on(outputStream* s); |
| }; |
| |
| #endif // SHARE_VM_UTILITIES_NUMBERSEQ_HPP |