ysr@777: /*
brutisso@3641:  * Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved.
ysr@777:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
ysr@777:  *
ysr@777:  * This code is free software; you can redistribute it and/or modify it
ysr@777:  * under the terms of the GNU General Public License version 2 only, as
ysr@777:  * published by the Free Software Foundation.
ysr@777:  *
ysr@777:  * This code is distributed in the hope that it will be useful, but WITHOUT
ysr@777:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
ysr@777:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
ysr@777:  * version 2 for more details (a copy is included in the LICENSE file that
ysr@777:  * accompanied this code).
ysr@777:  *
ysr@777:  * You should have received a copy of the GNU General Public License version
ysr@777:  * 2 along with this work; if not, write to the Free Software Foundation,
ysr@777:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
ysr@777:  *
trims@1907:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907:  * or visit www.oracle.com if you need additional information or have any
trims@1907:  * questions.
ysr@777:  *
ysr@777:  */
ysr@777: 
stefank@2314: #ifndef SHARE_VM_UTILITIES_NUMBERSEQ_HPP
stefank@2314: #define SHARE_VM_UTILITIES_NUMBERSEQ_HPP
stefank@2314: 
zgu@3900: #include "memory/allocation.hpp"
zgu@3900: 
ysr@777: /**
ysr@777:  **  This file contains a few classes that represent number sequence,
ysr@777:  **  x1, x2, x3, ..., xN, and can calculate their avg, max, and sd.
ysr@777:  **
ysr@777:  **  Here's a quick description of the classes:
ysr@777:  **
ysr@777:  **    AbsSeq: abstract superclass
ysr@777:  **    NumberSeq: the sequence is assumed to be very long and the
ysr@777:  **      maximum, avg, sd, davg, and dsd are calculated over all its elements
ysr@777:  **    TruncatedSeq: this class keeps track of the last L elements
ysr@777:  **      of the sequence and calculates avg, max, and sd only over them
ysr@777:  **/
ysr@777: 
ysr@777: #define DEFAULT_ALPHA_VALUE 0.7
ysr@777: 
zgu@3900: class AbsSeq: public CHeapObj<mtInternal> {
ysr@777: private:
ysr@777:   void init(double alpha);
ysr@777: 
ysr@777: protected:
ysr@777:   int    _num; // the number of elements in the sequence
ysr@777:   double _sum; // the sum of the elements in the sequence
ysr@777:   double _sum_of_squares; // the sum of squares of the elements in the sequence
ysr@777: 
ysr@777:   double _davg; // decaying average
ysr@777:   double _dvariance; // decaying variance
ysr@777:   double _alpha; // factor for the decaying average / variance
ysr@777: 
ysr@777:   // This is what we divide with to get the average. In a standard
ysr@777:   // number sequence, this should just be the number of elements in it.
ysr@777:   virtual double total() const { return (double) _num; };
ysr@777: 
ysr@777: public:
ysr@777:   AbsSeq(double alpha = DEFAULT_ALPHA_VALUE);
ysr@777: 
ysr@777:   virtual void add(double val); // adds a new element to the sequence
ysr@777:   void add(unsigned val) { add((double) val); }
ysr@777:   virtual double maximum() const = 0; // maximum element in the sequence
ysr@777:   virtual double last() const = 0; // last element added in the sequence
ysr@777: 
ysr@777:   // the number of elements in the sequence
ysr@777:   int num() const { return _num; }
ysr@777:   // the sum of the elements in the sequence
ysr@777:   double sum() const { return _sum; }
ysr@777: 
ysr@777:   double avg() const; // the average of the sequence
ysr@777:   double variance() const; // the variance of the sequence
ysr@777:   double sd() const; // the standard deviation of the sequence
ysr@777: 
ysr@777:   double davg() const; // decaying average
ysr@777:   double dvariance() const; // decaying variance
ysr@777:   double dsd() const; // decaying "standard deviation"
ysr@1521: 
ysr@1521:   // Debugging/Printing
ysr@1521:   virtual void dump();
ysr@1521:   virtual void dump_on(outputStream* s);
ysr@777: };
ysr@777: 
ysr@777: class NumberSeq: public AbsSeq {
ysr@777: private:
ysr@777:   bool check_nums(NumberSeq* total, int n, NumberSeq** parts);
ysr@777: 
ysr@777: protected:
ysr@777:   double _last;
ysr@777:   double _maximum; // keep track of maximum value
ysr@777: 
ysr@777: public:
ysr@777:   NumberSeq(double alpha = DEFAULT_ALPHA_VALUE);
ysr@777: 
ysr@777:   virtual void add(double val);
ysr@777:   virtual double maximum() const { return _maximum; }
ysr@777:   virtual double last() const { return _last; }
ysr@1521: 
ysr@1521:   // Debugging/Printing
ysr@1521:   virtual void dump_on(outputStream* s);
ysr@777: };
ysr@777: 
ysr@777: class TruncatedSeq: public AbsSeq {
ysr@777: private:
ysr@777:   enum PrivateConstants {
ysr@777:     DefaultSeqLength = 10
ysr@777:   };
ysr@777:   void init();
ysr@777: protected:
ysr@777:   double *_sequence; // buffers the last L elements in the sequence
ysr@777:   int     _length; // this is L
ysr@777:   int     _next;   // oldest slot in the array, i.e. next to be overwritten
ysr@777: 
ysr@777: public:
ysr@777:   // accepts a value for L
ysr@777:   TruncatedSeq(int length = DefaultSeqLength,
ysr@777:                double alpha = DEFAULT_ALPHA_VALUE);
brutisso@3641:   ~TruncatedSeq();
ysr@777:   virtual void add(double val);
ysr@777:   virtual double maximum() const;
ysr@777:   virtual double last() const; // the last value added to the sequence
ysr@777: 
ysr@777:   double oldest() const; // the oldest valid value in the sequence
ysr@777:   double predict_next() const; // prediction based on linear regression
ysr@1521: 
ysr@1521:   // Debugging/Printing
ysr@1521:   virtual void dump_on(outputStream* s);
ysr@777: };
stefank@2314: 
stefank@2314: #endif // SHARE_VM_UTILITIES_NUMBERSEQ_HPP