Derivator.h

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/*
 *  CepGen: a central exclusive processes event generator
 *  Copyright (C) 2022-2024  Laurent Forthomme
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
#ifndef CepGen_Utils_Derivator_h
#define CepGen_Utils_Derivator_h
 
#include "CepGen/Modules/NamedModule.h"
#include "CepGen/Utils/FunctionsWrappers.h"
 
namespace cepgen {
  namespace utils {
    class Derivator : public NamedModule<Derivator> {
    public:
      explicit Derivator(const ParametersList& params) : NamedModule(params), h_(steer<double>("h")) {}
 
      static ParametersDescription description() {
        auto desc = ParametersDescription();
        desc.add<double>("h", 1.e-2).setDescription("step size");
        return desc;
      }
 
      inline double derivate(const std::function<double(double)>& func, double x, double h = -1.) const {
        return derivate(Function1D(func), x, h);
      }
      virtual double derivate(const Function1D& func, double x, double h = -1.) const = 0;
 
    protected:
      const double h_;
    };
  }  // namespace utils
}  // namespace cepgen
 
#endif