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AnnealingUtility.cpp
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1 // This file is part of the Acts project.
2 //
3 // Copyright (C) 2019 CERN for the benefit of the Acts project
4 //
5 // This Source Code Form is subject to the terms of the Mozilla Public
6 // License, v. 2.0. If a copy of the MPL was not distributed with this
7 // file, You can obtain one at http://mozilla.org/MPL/2.0/.
8 
10 
17 static double gaussFunc(double chi2, double temp) {
18  return std::exp(-chi2 / (2. * temp));
19 }
20 
22  if (state.currentTemperatureIndex < m_cfg.setOfTemperatures.size() - 1) {
24  } else {
25  state.equilibriumReached = true;
26  }
27 }
28 
30  State& state, double chi2, const std::vector<double>& allChi2) const {
31  const double currentTemp =
32  m_cfg.setOfTemperatures[state.currentTemperatureIndex];
33 
34  double base = gaussFunc(1., currentTemp);
35 
36  double denom = std::pow(base, m_cfg.cutOff - chi2);
37 
38  for (double val : allChi2) {
39  denom += std::pow(base, val - chi2);
40  }
41 
42  return 1. / denom;
43 }
44 
45 double Acts::AnnealingUtility::getWeight(State& state, double chi2) const {
46  const double currentTemp =
47  m_cfg.setOfTemperatures[state.currentTemperatureIndex];
48 
49  return 1. / (1. + gaussFunc(m_cfg.cutOff - chi2, currentTemp));
50 }