distributions.h

这是关于覆盖网的各种负载均衡算法的程序。好好研究

/* $Id: distributions.h,v 1.8 2005/08/02 19:35:49 jonathan Exp $
 * Jonathan Ledlie, Harvard University.
 * Copyright 2005.  All rights reserved.
 */

#ifndef DISTRIBUTIONS_H_
#define DISTRIBUTIONS_H_

#include <map>
#include <vector>
#include "randlib.h"
#include "math_util.h"
using namespace::std;

class Distribution {
public:
  Distribution () {}
  ~Distribution () {}
  virtual double next () { return 0.;}
  virtual double getMean () { return 0.;}
  virtual char getName () {return ' ';}
};

class ParetoDistribution : public Distribution {
private:
  double scale;
  double shape;
public:
  ParetoDistribution (double sc, double sh) {this->scale = sc; this->shape = sh;}
  ~ParetoDistribution () {}
  double next ();
  double getMean ();
  char getName () { return 'p';};
};

class NormalDistribution : public Distribution {
private:
  double mean;
  double stddev;
public:
  NormalDistribution (double m, double s) {this->mean = m; this->stddev = s;}
  ~NormalDistribution () {}
  double next ();
  double getMean ();
  char getName () { return 'n';};
};

class ZipfDistribution : public Distribution {
private:
  double alpha;
  int elements;
  double c;          // Normalization constant
public:
  ZipfDistribution (double a, int n);
  ~ZipfDistribution () {}
  double next ();
  double getMean ();
  char getName () { return 'z';};
  map<double,double> zipfKeys;
};

class UniformDistribution : public Distribution {
private:
public:
  UniformDistribution () {}
  ~UniformDistribution () {}
  double next ();
  double getMean ();
  char getName () { return 'u';};
};

class GnutellaBWDistribution : public Distribution {
private:
public:
  GnutellaBWDistribution () {}
  ~GnutellaBWDistribution () {}
  double next ();
  double getMean ();
  char getName () { return 'g';};
};

class PoissonDistribution : public Distribution {
private:
  double mean;
public:
  PoissonDistribution (double m) {this->mean = m;}
  ~PoissonDistribution () {}
  double next ();
  double getMean ();
  char getName () { return 'f';};
};

class ConstantDistribution : public Distribution {
private:
  double value;
public:
  ConstantDistribution (double c) {this->value = c;}
  ~ConstantDistribution () {}
  double next ();
  double getMean ();
  char getName () { return 'c';};
};

class DistributionFactory {
public:
  DistributionFactory () {}
  ~DistributionFactory () {}
  Distribution* newDistribution (char *str);
};

double snorm();

#endif