Quadratic.hh

Go to the documentation of this file.

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

    template <typename Scalar>
      requires TypeTrait<Scalar>::IsScalar
    class Quadratic : public Function<Scalar, Scalar, Quadratic<Scalar>> {
      Scalar m_a{1.0};  
      Scalar m_b{1.0};  
      Scalar m_c{-1.0}; 
 
     public:
      OPTIMIST_BASIC_CONSTANTS(Scalar)
 
      
      Quadratic() {
        Scalar delta{static_cast<Scalar>(
            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));  // Zero
        this->m_solutions.emplace_back((-this->m_b - delta) /
                                       (2.0 * this->m_a));  // Zero
        this->m_solutions.emplace_back(-this->m_b /
                                       (2.0 * this->m_a));  // Minimum
        this->m_guesses.emplace_back(0.0);
      }

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

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

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

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