Alexandria  2.19
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linear.cpp
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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 
29 #include <limits>
30 
31 namespace Euclid {
32 namespace MathUtils {
33 
36  for (size_t i = 0; i < x.size() - 1; i++) {
37  double coef1 = (y[i + 1] - y[i]) / (x[i + 1] - x[i]);
38  double coef0 = y[i] - coef1 * x[i];
39  functions.push_back(std::shared_ptr<Function>(new Polynomial{{coef0, coef1}}));
40  }
41 
42  if (extrapolate) {
43  std::vector<double> x_copy(x);
46  return std::unique_ptr<Function>(new Piecewise{x_copy, std::move(functions)});
47  }
48 
49  return std::unique_ptr<Function>(new Piecewise{x, std::move(functions)});
50 }
51 
52 } // namespace MathUtils
53 } // end of namespace Euclid
T front(T...args)
Represents a polynomial function.
Definition: Polynomial.h:43
T push_back(T...args)
T lowest(T...args)
T move(T...args)
T size(T...args)
STL class.
std::unique_ptr< Function > linearInterpolation(const std::vector< double > &x, const std::vector< double > &y, bool extrapolate)
Performs linear interpolation for the given set of data points.
Definition: linear.cpp:34
T back(T...args)
Represents a piecewise function.
Definition: Piecewise.h:48