ESPResSo
Extensible Simulation Package for Research on Soft Matter Systems
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RunningAverage.hpp
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1/*
2 * Copyright (C) 2010-2022 The ESPResSo project
3 * Copyright (C) 2002,2003,2004,2005,2006,2007,2008,2009,2010
4 * Max-Planck-Institute for Polymer Research, Theory Group
5 *
6 * This file is part of ESPResSo.
7 *
8 * ESPResSo is free software: you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation, either version 3 of the License, or
11 * (at your option) any later version.
12 *
13 * ESPResSo is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program. If not, see <http://www.gnu.org/licenses/>.
20 */
21
22#ifndef STATISTICS_RUNING_AVERAGE_HPP
23#define STATISTICS_RUNING_AVERAGE_HPP
24
25#include <algorithm>
26#include <cmath>
27#include <limits>
28
29namespace Utils {
30namespace Statistics {
31
32/**
33 * \brief Keep running average and variance.
34 * The average should be numerically stable.
35 */
36template <typename Scalar> class RunningAverage {
37public:
39 : m_n(0), m_old_avg(0), m_new_avg(0), m_old_var(0), m_new_var(0.0),
40 m_min(std::numeric_limits<Scalar>::max()),
41 m_max(-std::numeric_limits<Scalar>::max()) {}
42 void add_sample(Scalar s) {
43 m_n++;
44
45 if (m_n == 1) {
46 m_old_avg = m_new_avg = s;
47 } else {
48 m_new_avg = m_old_avg + (s - m_old_avg) / m_n;
49 m_new_var = m_old_var + (s - m_old_avg) * (s - m_new_avg);
50
51 m_old_avg = m_new_avg;
52 m_old_var = m_new_var;
53 }
54
55 m_min = std::min(m_min, s);
56 m_max = std::max(m_max, s);
57 }
58
59 void clear() { m_n = 0; }
60
61 int n() const { return m_n; }
62
63 /** Average of the samples */
64 Scalar avg() const {
65 if (m_n > 0)
66 return m_new_avg;
67
68 return 0.0;
69 }
70 /** Variance of the samples */
71 Scalar var() const {
72 if (m_n > 1)
73 return m_new_var / m_n;
74
75 return 0.0;
76 }
77
78 /** Standard deviation of the samples */
79 Scalar sig() const { return std::sqrt(var()); }
80
81 /** Minimum */
82 Scalar min() const { return m_min; }
83
84 /** Minimum */
85 Scalar max() const { return m_max; }
86
87private:
88 int m_n;
89 Scalar m_old_avg, m_new_avg;
90 Scalar m_old_var, m_new_var;
91 Scalar m_min, m_max;
92};
93} // namespace Statistics
94} // namespace Utils
95
96#endif
Keep running average and variance.
Scalar avg() const
Average of the samples.
Scalar sig() const
Standard deviation of the samples.
Scalar var() const
Variance of the samples.