Cos.hh

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/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *\
 * 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_COS_HH
#define OPTIMIST_TESTSET_COS_HH
 
#include "Optimist/Function.hh"
 
namespace Optimist {
 
  namespace TestSet {

    template <typename Scalar>
      requires TypeTrait<Scalar>::IsScalar
    class Cos : public Function<Scalar, Scalar, Cos<Scalar>> {
     public:
      OPTIMIST_BASIC_CONSTANTS(Scalar)
 
      
      Cos() {
        this->m_solutions.emplace_back(-M_PI / 2.0);  // Zero
        this->m_solutions.emplace_back(M_PI / 2.0);   // Zero
        this->m_solutions.emplace_back(-M_PI);        // Minimum
        this->m_solutions.emplace_back(M_PI);         // Minimum
        this->m_guesses.emplace_back(-3.0 / 8.0 * M_PI);
        this->m_guesses.emplace_back(3.0 / 8.0 * M_PI);
      }

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

      bool evaluate_impl(const Scalar x, Scalar &out) const {
        out = std::cos(x);
        return std::isfinite(out);
      }

      bool first_derivative_impl(const Scalar x, Scalar &out) const {
        out = -std::sin(x);
        return std::isfinite(out);
      }

      bool second_derivative_impl(const Scalar x, Scalar &out) const {
        out = -std::cos(x);
        return std::isfinite(out);
      }
 
    };  // class Cos
 
  }  // namespace TestSet
 
}  // namespace Optimist
 
#endif  // OPTIMIST_TESTSET_COS_HH