jdk8-mips64-public/hotspot: src/share/vm/utilities/numberSeq.hpp@f4f596978298

     1 /*

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    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).

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    25 /**

    26  **  This file contains a few classes that represent number sequence,

    27  **  x1, x2, x3, ..., xN, and can calculate their avg, max, and sd.

    28  **

    29  **  Here's a quick description of the classes:

    30  **

    31  **    AbsSeq: abstract superclass

    32  **    NumberSeq: the sequence is assumed to be very long and the

    33  **      maximum, avg, sd, davg, and dsd are calculated over all its elements

    34  **    TruncatedSeq: this class keeps track of the last L elements

    35  **      of the sequence and calculates avg, max, and sd only over them

    36  **/

    38 #define DEFAULT_ALPHA_VALUE 0.7

    40 class AbsSeq {

    41 private:

    42   void init(double alpha);

    44 protected:

    45   int    _num; // the number of elements in the sequence

    46   double _sum; // the sum of the elements in the sequence

    47   double _sum_of_squares; // the sum of squares of the elements in the sequence

    49   double _davg; // decaying average

    50   double _dvariance; // decaying variance

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

    53   // This is what we divide with to get the average. In a standard

    54   // number sequence, this should just be the number of elements in it.

    55   virtual double total() const { return (double) _num; };

    57 public:

    58   AbsSeq(double alpha = DEFAULT_ALPHA_VALUE);

    60   virtual void add(double val); // adds a new element to the sequence

    61   void add(unsigned val) { add((double) val); }

    62   virtual double maximum() const = 0; // maximum element in the sequence

    63   virtual double last() const = 0; // last element added in the sequence

    65   // the number of elements in the sequence

    66   int num() const { return _num; }

    67   // the sum of the elements in the sequence

    68   double sum() const { return _sum; }

    70   double avg() const; // the average of the sequence

    71   double variance() const; // the variance of the sequence

    72   double sd() const; // the standard deviation of the sequence

    74   double davg() const; // decaying average

    75   double dvariance() const; // decaying variance

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

    78   // Debugging/Printing

    79   virtual void dump();

    80   virtual void dump_on(outputStream* s);

    81 };

    83 class NumberSeq: public AbsSeq {

    84 private:

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

    87 protected:

    88   double _last;

    89   double _maximum; // keep track of maximum value

    91 public:

    92   NumberSeq(double alpha = DEFAULT_ALPHA_VALUE);

    93   NumberSeq(NumberSeq* total, int n_parts, NumberSeq** parts);

    95   virtual void add(double val);

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

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

    99   // Debugging/Printing

   100   virtual void dump_on(outputStream* s);

   101 };

   103 class TruncatedSeq: public AbsSeq {

   104 private:

   105   enum PrivateConstants {

   106     DefaultSeqLength = 10

   107   };

   108   void init();

   109 protected:

   110   double *_sequence; // buffers the last L elements in the sequence

   111   int     _length; // this is L

   112   int     _next;   // oldest slot in the array, i.e. next to be overwritten

   114 public:

   115   // accepts a value for L

   116   TruncatedSeq(int length = DefaultSeqLength,

   117                double alpha = DEFAULT_ALPHA_VALUE);

   118   virtual void add(double val);

   119   virtual double maximum() const;

   120   virtual double last() const; // the last value added to the sequence

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

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

   125   // Debugging/Printing

   126   virtual void dump_on(outputStream* s);

   127 };

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