Alexandria  2.22.0
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Solvers.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
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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 
20 #include <cmath>
21 
22 namespace Euclid {
23 namespace MathUtils {
24 
25 std::pair<double, double> solveSquare(double a, double b, double c, double y) {
26  if (a != 0.) {
27  double exprb = b / (2 * a);
28  exprb *= exprb;
29  double sr = std::sqrt((y - c) / a + exprb);
30  return std::make_pair(-sr - b / (2 * a), sr - b / (2 * a));
31  } else if (b != 0.) {
32  return std::make_pair((y - c) / b, (y - c) / b);
33  }
34  throw Elements::Exception() << "Can not solve y = 0x^2 + 0x + c";
35 }
36 
37 } // namespace MathUtils
38 } // namespace Euclid
T make_pair(T... args)
constexpr double sr
std::pair< double, double > solveSquare(double a, double b, double c, double y)
Definition: Solvers.cpp:25
T sqrt(T... args)