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