jdk8-mips64-public/hotspot: src/share/vm/utilities/numberSeq.hpp@dc1769738300

     1 /*

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     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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     6  * under the terms of the GNU General Public License version 2 only, as

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    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  *

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    25 #ifndef SHARE_VM_UTILITIES_NUMBERSEQ_HPP

    26 #define SHARE_VM_UTILITIES_NUMBERSEQ_HPP

    28 #include "memory/allocation.hpp"

    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  **/

    43 #define DEFAULT_ALPHA_VALUE 0.7

    45 class AbsSeq: public CHeapObj<mtInternal> {

    46 private:

    47   void init(double alpha);

    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

    54   double _davg; // decaying average

    55   double _dvariance; // decaying variance

    56   double _alpha; // factor for the decaying average / variance

    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; };

    62 public:

    63   AbsSeq(double alpha = DEFAULT_ALPHA_VALUE);

    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

    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; }

    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

    79   double davg() const; // decaying average

    80   double dvariance() const; // decaying variance

    81   double dsd() const; // decaying "standard deviation"

    83   // Debugging/Printing

    84   virtual void dump();

    85   virtual void dump_on(outputStream* s);

    86 };

    88 class NumberSeq: public AbsSeq {

    89 private:

    90   bool check_nums(NumberSeq* total, int n, NumberSeq** parts);

    92 protected:

    93   double _last;

    94   double _maximum; // keep track of maximum value

    96 public:

    97   NumberSeq(double alpha = DEFAULT_ALPHA_VALUE);

    99   virtual void add(double val);

   100   virtual double maximum() const { return _maximum; }

   101   virtual double last() const { return _last; }

   103   // Debugging/Printing

   104   virtual void dump_on(outputStream* s);

   105 };

   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

   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

   127   double oldest() const; // the oldest valid value in the sequence

   128   double predict_next() const; // prediction based on linear regression

   130   // Debugging/Printing

   131   virtual void dump_on(outputStream* s);

   132 };

   134 #endif // SHARE_VM_UTILITIES_NUMBERSEQ_HPP

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