Quadratic.hh

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/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *\
 * Copyright (c) 2025, Davide Stocco, Mattia Piazza and Enrico Bertolazzi.                       *
 *                                                                                               *
 * The Optimist project is distributed under the BSD 2-Clause License.                           *
 *                                                                                               *
 * Davide Stocco                          Mattia Piazza                        Enrico Bertolazzi *
 * University of Trento               University of Trento                  University of Trento *
 * davide.stocco@unitn.it            mattia.piazza@unitn.it           enrico.bertolazzi@unitn.it *
\* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 
#pragma once
 
#ifndef OPTIMIST_TESTSET_QUADRATIC_HH
#define OPTIMIST_TESTSET_QUADRATIC_HH
 
#include "Optimist/TestSet.hh"
 
namespace Optimist
{
 
  namespace TestSet
  {

    template <typename Real>
    class Quadratic : public Function<Real, 1, 1, Quadratic<Real>>
    {
      Real m_a{1.0}; 
      Real m_b{1.0}; 
      Real m_c{-1.0}; 
 
    public:
      OPTIMIST_BASIC_CONSTANTS(Real)
 
      
      Quadratic()
      {
        Real delta{std::sqrt(this->m_b*this->m_b - 4.0*this->m_a*this->m_c)};
        this->m_solutions.emplace_back((-this->m_b + delta)/(2.0*this->m_a));
        this->m_solutions.emplace_back((-this->m_b - delta)/(2.0*this->m_a));
        this->m_solutions.emplace_back(this->m_b/(2.0*this->m_a));
        this->m_guesses.emplace_back(0.0);
      }

      std::string name_impl() const {return "Quadratic";}

      bool evaluate_impl(Real x, Real & out) const
      {
        out = this->m_a*x*x + this->m_b*x + this->m_c;
        return std::isfinite(out);
      }

      bool first_derivative_impl(Real x, Real & out) const
      {
        out = 2.0*this->m_a*x + this->m_b;
        return std::isfinite(out);
      }

      bool second_derivative_impl(Real /*x*/, Real & out) const
      {
        out = 2.0*this->m_a;
        return std::isfinite(out);
      }
 
    }; // class Quadratic
 
  } // namespace TestSet
 
} // namespace Optimist
 
#endif // OPTIMIST_TESTSET_QUADRATIC_HH