MSVesuvioHelpers.h

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// Mantid Repository : https://github.com/mantidproject/mantid
//
// Copyright © 2018 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
 
#include "MantidKernel/normal_distribution.h"
#include <random>
#include <vector>
 
namespace Mantid {
namespace CurveFitting {
namespace MSVesuvioHelper {
// Absorption energy for double-difference gold foil
double finalEnergyAuDD(const double randv);
// Absorption energy for gold foil YAP
double finalEnergyAuYap(const double randv);
// Absorption energy for uranium
double finalEnergyUranium(const double randv);
 
// Ties together random numbers with various probability distributions
class RandomVariateGenerator {
public:
  RandomVariateGenerator(const int seed);
  double flat();
  double gaussian(const double mean, const double sigma);
 
private:
  RandomVariateGenerator();
  std::mt19937 m_engine;
};
 
// Stores counts for each scatter order
// for a "run" of a given number of events
struct Simulation {
  Simulation(const size_t order, const size_t ntimes);
 
  std::vector<std::vector<double>> counts;
  size_t maxorder;
};
// Stores counts for each scatter order with errors
struct SimulationWithErrors {
  SimulationWithErrors(const size_t order, const size_t ntimes)
      : sim(order, ntimes), errors(order, std::vector<double>(ntimes)) {}
 
  void normalise();
  Simulation sim;
  std::vector<std::vector<double>> errors;
};
 
// Accumulates and averages the results of a set of simulations
struct SimulationAggregator {
  SimulationAggregator(const size_t nruns);
 
  // Creates a placeholder for a new simulation
  Simulation &newSimulation(const size_t order, const size_t ntimes);
  SimulationWithErrors average() const;
 
  std::vector<Simulation> results;
};
} // namespace MSVesuvioHelper
} // namespace CurveFitting
} // namespace Mantid