Random.h

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/*      
 * File: Random.h
 * Project: DUtils library
 * Author: Dorian Galvez-Lopez
 * Date: April 2010, November 2011
 * Description: manages pseudo-random numbers
 * License: see the LICENSE.txt file
 *
 */
 
#pragma once
#ifndef __D_RANDOM__
#define __D_RANDOM__
 
#include <cstdlib>
#include <vector>
 
namespace DUtils {
 
class Random
{
public:
  class UnrepeatedRandomizer;
  
public:
        static void SeedRand();
        
        static void SeedRandOnce();
 
        static void SeedRand(int seed);
 
        static void SeedRandOnce(int seed);
 
        template <class T>
        static T RandomValue(){
                return (T)rand()/(T)RAND_MAX;
        }
 
        template <class T>
        static T RandomValue(T min, T max){
                return Random::RandomValue<T>() * (max - min) + min;
        }
 
        static int RandomInt(int min, int max);
        
        template <class T>
        static T RandomGaussianValue(T mean, T sigma)
        {
    // Box-Muller transformation
    T x1, x2, w, y1;
 
    do {
      x1 = (T)2. * RandomValue<T>() - (T)1.;
      x2 = (T)2. * RandomValue<T>() - (T)1.;
      w = x1 * x1 + x2 * x2;
    } while ( w >= (T)1. || w == (T)0. );
 
    w = sqrt( ((T)-2.0 * log( w ) ) / w );
    y1 = x1 * w;
 
    return( mean + y1 * sigma );
        }
 
private:
 
  static bool m_already_seeded;
  
};
 
// ---------------------------------------------------------------------------
 
class Random::UnrepeatedRandomizer
{
public:
 
  UnrepeatedRandomizer(int min, int max);
  ~UnrepeatedRandomizer(){}
  
  UnrepeatedRandomizer(const UnrepeatedRandomizer& rnd);
  
  UnrepeatedRandomizer& operator=(const UnrepeatedRandomizer& rnd);
  
  int get();
  
  inline bool empty() const { return m_values.empty(); }
  
  inline unsigned int left() const { return m_values.size(); }
  
  void reset();
  
protected:
 
  void createValues();
 
protected:
 
  int m_min;
  int m_max;
 
  std::vector<int> m_values;
 
};
 
}
 
#endif