Alexandria  2.27.0
SDC-CH common library for the Euclid project
Cumulative.cpp
Go to the documentation of this file.
1 /*
2  * Copyright (C) 2012-2021 Euclid Science Ground Segment
3  *
4  * This library is free software; you can redistribute it and/or modify it under
5  * the terms of the GNU Lesser General Public License as published by the Free
6  * Software Foundation; either version 3.0 of the License, or (at your option)
7  * any later version.
8  *
9  * This library is distributed in the hope that it will be useful, but WITHOUT
10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
11  * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
12  * details.
13  *
14  * You should have received a copy of the GNU Lesser General Public License
15  * along with this library; if not, write to the Free Software Foundation, Inc.,
16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17  */
18 
27 #include "XYDataset/XYDataset.h"
28 #include <cstdlib> // for size_t
29 
30 namespace Euclid {
31 namespace MathUtils {
32 
34  : m_x_sampling(x_sampling), m_y_sampling(y_sampling) {
35  if (x_sampling.size() != y_sampling.size()) {
36  throw Elements::Exception("Cumulative: X and Y sampling do not have the same length.");
37  }
38 }
39 
40 Cumulative::Cumulative(const XYDataset::XYDataset& sampling) : m_x_sampling{}, m_y_sampling{} {
41  auto iter = sampling.begin();
42  while (iter != sampling.end()) {
43  m_x_sampling.push_back((*iter).first);
44  m_y_sampling.push_back((*iter).second);
45  ++iter;
46  }
47 }
48 
52  auto iter = sampling.begin();
53  while (iter != sampling.end()) {
54  xs.push_back((*iter).first);
55  ys.push_back((*iter).second);
56  ++iter;
57  }
58  return Cumulative::fromPdf(xs, ys);
59 }
60 
62  double total = 0.;
63  std::vector<double> cumul{};
64  auto iter_pdf = pdf_sampling.cbegin();
65 
66  while (iter_pdf != pdf_sampling.cend()) {
67  total += *(iter_pdf);
68  cumul.push_back(total);
69  ++iter_pdf;
70  }
71 
72  return Cumulative(x_sampling, cumul);
73 }
74 
76  double total = m_y_sampling.back();
77  std::vector<double> cumul{};
78  auto iter = m_y_sampling.begin();
79  while (iter != m_y_sampling.end()) {
80  cumul.push_back(*iter / total);
81  ++iter;
82  }
83 
84  m_y_sampling = std::move(cumul);
85 }
86 
87 double Cumulative::findValue(double ratio, TrayPosition position) const {
88 
89  if (ratio > 1. || ratio < 0.) {
90  throw Elements::Exception("Cumulative::findValue : ratio parameter must be in range [0,1]");
91  }
92 
93  double value = m_y_sampling.back() * ratio;
94 
95  auto iter_x = m_x_sampling.cbegin();
96  auto iter_y = m_y_sampling.cbegin();
97  while (iter_y != m_y_sampling.cend() && (*iter_y) < value) {
98  ++iter_x;
99  ++iter_y;
100  }
101 
102  double begin_value = *iter_x;
103  double tray = *iter_y;
104  while (iter_y != m_y_sampling.cend() && (*iter_y) == tray) {
105  ++iter_x;
106  ++iter_y;
107  }
108 
109  double end_value = *(--iter_x);
110 
111  double result = 0;
112  switch (position) {
113  case TrayPosition::begin:
114  result = begin_value;
115  break;
116  case TrayPosition::middle:
117  result = 0.5 * (begin_value + end_value);
118  break;
119  case TrayPosition::end:
120  result = end_value;
121  break;
122  }
123 
124  return result;
125 }
126 
128 
129  if (rate > 1. || rate <= 0.) {
130  throw Elements::Exception("Cumulative::findMinInterval : rate parameter must be in range ]0,1]");
131  }
132 
133  rate *= m_y_sampling.back();
134 
135  double first_correction = m_y_sampling.front();
136 
137  auto iter_1_x = m_x_sampling.cbegin();
138  auto iter_2_x = ++(m_x_sampling.cbegin());
139  auto iter_1_y = m_y_sampling.cbegin();
140  auto iter_2_y = ++(m_y_sampling.cbegin());
141  auto min_x = m_x_sampling.cbegin();
142  auto max_x = --(m_x_sampling.cend());
143  while (iter_1_x != m_x_sampling.cend()) {
144  while (iter_2_x != m_x_sampling.cend() && (*iter_2_y - *iter_1_y + first_correction) < rate) {
145  ++iter_2_x;
146  ++iter_2_y;
147  }
148  if (iter_2_x == m_x_sampling.cend()) {
149  break;
150  }
151  if ((*iter_2_x - *iter_1_x) <= (*max_x - *min_x)) {
152  max_x = iter_2_x;
153  min_x = iter_1_x;
154  }
155  ++iter_1_x;
156  ++iter_1_y;
157  first_correction = 0.;
158  }
159 
160  return std::make_pair(*min_x, *max_x);
161 }
162 
164 
165  if (rate > 1. || rate <= 0.) {
166  throw Elements::Exception("Cumulative::findCenteredInterval : rate parameter must be in range ]0,1]");
167  }
168 
169  double min_value = m_y_sampling.back() * (0.5 - rate / 2.0);
170  double max_value = m_y_sampling.back() * (0.5 + rate / 2.0);
171 
172  auto iter_x = m_x_sampling.cbegin();
173  auto iter_y = m_y_sampling.cbegin();
174  while (iter_y != m_y_sampling.cend() && (*iter_y) < min_value) {
175  ++iter_x;
176  ++iter_y;
177  }
178 
179  if ((*iter_y) < max_value) {
180  double tray = *iter_y;
181  while (iter_y != m_y_sampling.cend() && (*iter_y) == tray) {
182  ++iter_x;
183  ++iter_y;
184  }
185  double min_x = (iter_x != m_x_sampling.begin()) ? *(iter_x - 1) : *iter_x;
186 
187  while (iter_y != m_y_sampling.cend() && (*iter_y) < max_value) {
188  ++iter_x;
189  ++iter_y;
190  }
191  double max_x = *iter_x;
192 
193  return std::make_pair(min_x, max_x);
194  } else {
195  double min_x = (iter_x != m_x_sampling.begin()) ? *(iter_x - 1) : *iter_x;
196  double max_x = *iter_x;
197 
198  return std::make_pair(min_x, max_x);
199  }
200 }
201 
202 } // namespace MathUtils
203 } // namespace Euclid
T back(T... args)
T cbegin(T... args)
Class for build cumulative from PDF and extract feature out of it.
Definition: Cumulative.h:41
Cumulative(Cumulative &&other)=default
move constructor
TrayPosition
when looking for the position having a given value, one may encounter tray where the value is constan...
Definition: Cumulative.h:51
std::vector< double > m_x_sampling
Definition: Cumulative.h:154
std::pair< double, double > findCenteredInterval(double rate) const
return the horizontal interval starting where the Cumulative has value (1-ratio)/2 and ending where t...
Definition: Cumulative.cpp:163
std::vector< double > m_y_sampling
Definition: Cumulative.h:155
void normalize()
Normalize the Cumulative. After calling this function the last vertical value is 1....
Definition: Cumulative.cpp:75
double findValue(double ratio, TrayPosition position=TrayPosition::middle) const
Find the first horizontal sample which vertical value is bigger or equal to the ratio value....
Definition: Cumulative.cpp:87
std::pair< double, double > findMinInterval(double rate) const
Scan the horizontal axis looking for the smallest x-interval for which the vertical interval is at le...
Definition: Cumulative.cpp:127
static Cumulative fromPdf(std::vector< double > &x_sampling, std::vector< double > &pdf_sampling)
Factory from the sampling of a PDF. The Cumulative vertical samples are build as the sum of the the p...
Definition: Cumulative.cpp:61
This module provides an interface for accessing two dimensional datasets (pairs of (X,...
Definition: XYDataset.h:59
const_iterator begin() const
Returns a const iterator to the first pair of the dataset.
Definition: XYDataset.cpp:36
const_iterator end() const
Returns a const iterator to the one after last pair dataset.
Definition: XYDataset.cpp:40
T cend(T... args)
T front(T... args)
T make_pair(T... args)
T move(T... args)
T push_back(T... args)
T size(T... args)