randomNumbers_MT19937.h

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#ifndef RANDOMNUMBERS_MT19937_INCLUDED
#define RANDOMNUMBERS_MT19937_INCLUDED

//==========================================================
//  Random number generator.
//     MT19937 random number generator.
//     Original version in C was written by
//     Takuji Nishimura and Makoto Matsumoto.
//     See URL http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/MT2002/mt19937ar.html
//
//                                 25 Dec 2004  H.Matsufuru
//==========================================================

#include <cmath>
#include <string>
#include <vector>

#include "randomNumbers.h"

class RandomNumbers_MT19937 : public RandomNumbers
{
 public:
  RandomNumbers_MT19937(int s);
  //RandomNumbers_MT19937(unsigned long s = 5489UL);
  RandomNumbers_MT19937(unsigned long s);
  RandomNumbers_MT19937(std::vector<unsigned long>& key);
  RandomNumbers_MT19937(const std::string filename);

  ~RandomNumbers_MT19937() {}

  double get() { return randDouble2(); }
  void writefile(const std::string);

 private:
  void init(unsigned long s);
  void init(unsigned long s, std::vector<unsigned long>& key);

  void nextState() const;
  unsigned long twist(unsigned long u, unsigned long v) const;

  // return [0,0xffffffff]
  unsigned long randInt32() const;

  // return [0,0x7fffffff]
  long randInt31() const;

  // return [0,1] random number
  double randDouble1() const;

  // return [0,1) random number
  double randDouble2() const;

  // return (0,1) random number
  double randDouble3() const;

  // return [0,1) random number with 53-bit resolution
  double randRes53() const;

  enum { N=624, M=397 };

  mutable int           m_left;
  mutable unsigned long m_state[N];
  mutable unsigned long *m_next;
};
#endif