MersenneTwister.h

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// Mantid Repository : https://github.com/mantidproject/mantid
//
// Copyright © 2010 ISIS Rutherford Appleton Laboratory UKRI,
//   NScD Oak Ridge National Laboratory, European Spallation Source,
//   Institut Laue - Langevin & CSNS, Institute of High Energy Physics, CAS
// SPDX - License - Identifier: GPL - 3.0 +
#pragma once
 
//------------------------------------------------------------------------------
// Includes
//------------------------------------------------------------------------------
#include "MantidKernel/PseudoRandomNumberGenerator.h"
 
#include <memory>
#include <random>
 
namespace Mantid {
namespace Kernel {
class MANTID_KERNEL_DLL MersenneTwister final : public PseudoRandomNumberGenerator {
 
public:
  MersenneTwister();
  MersenneTwister(const double start, const double end);
  explicit MersenneTwister(const size_t seedValue);
  MersenneTwister(const size_t seedValue, const double start, const double end);
 
  MersenneTwister(const MersenneTwister &) = delete;
  MersenneTwister &operator=(const MersenneTwister &) = delete;
 
  void setSeed(const size_t seedValue) override;
  void setRange(const double start, const double end) override;
  inline double nextValue() override { return uniformRealDistribution(m_engine); }
  inline double nextValue(double start, double end) override {
    return std::uniform_real_distribution<double>(start, end)(m_engine);
  }
  int nextInt(int start, int end) override;
  void restart() override;
  void save() override;
  void restore() override;
  double min() const override { return m_start; }
  double max() const override { return m_end; }
 
private:
  std::mt19937 m_engine;
  std::uniform_real_distribution<double> uniformRealDistribution;
  double m_start;
  double m_end;
  std::mt19937::result_type m_seed;
  std::unique_ptr<std::mt19937> m_savedEngine;
};
} // namespace Kernel
} // namespace Mantid