// This file is part of Bertini 2.
//
// jacobian.hpp 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
//(at your option) any later version.
//
// jacobian.hpp 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 jacobian.hpp.  If not, see <http://www.gnu.org/licenses/>.
//
//  Copyright(C) 2015 - 2021 by Bertini2 Development Team
//
//  See <http://www.gnu.org/licenses/> for a copy of the license,
//  as well as COPYING.  Bertini2 is provided with permitted
//  additional terms in the b2/licenses/ directory.

// individual authors of this file include:
//  James Collins
//  West Texas A&M University
//  Spring, Summer 2015
//
// silviana amethyst, university of wisconsin-eau claire
//
//  silviana amethyst
//  UWEC
//  Spring 2018
//
//  Created by Collins, James B. on 6/11/15.
//
//
// jacobian.hpp:  Declares the class Jacobian.

/**
\file jacobian.hpp

\brief Provides the Jacobian node type.

*/

#ifndef BERTINI_JACOBIAN_NODE_HPP
#define BERTINI_JACOBIAN_NODE_HPP

#include "function_tree/node.hpp"
#include "function_tree/roots/function.hpp"
#include "function_tree/symbols/variable.hpp"

namespace bertini {
namespace node {

/**
\brief Defines the entry point into a Jacobian tree.

 This class defines a Jacobian tree.  It stores the entry node for a particular
functions tree.
 */
class Jacobian : public virtual Handle,
                 public virtual EnableSharedFromThisVirtual<Jacobian> {
  friend detail::FreshEvalSelector<dbl>;
  friend detail::FreshEvalSelector<mpfr_complex>;

 public:
  BERTINI_DEFAULT_VISITABLE()

  template <typename... Ts>
  static std::shared_ptr<Jacobian> Make(Ts&&... ts) {
    return std::shared_ptr<Jacobian>(new Jacobian(ts...));
  }

 private:
  /**
   */
  Jacobian(const std::shared_ptr<Node>& entry);

 public:
  /**
   Jacobians must be evaluated with EvalJ, so that when current_diff_variable
   changes the Jacobian is reevaluated.
   */
  template <typename T>
  T Eval(std::shared_ptr<Variable> const& diff_variable = nullptr) const =
      delete;

  // Evaluate the node.  If flag false, just return value, if flag true
  //  run the specific FreshEval of the node, then set flag to false.
  template <typename T>
  T EvalJ(std::shared_ptr<Variable> const& diff_variable) const;

  // Evaluate the node.  If flag false, just return value, if flag true
  //  run the specific FreshEval of the node, then set flag to false.
  template <typename T>
  void EvalJInPlace(T& eval_value,
                    std::shared_ptr<Variable> const& diff_variable) const;

  virtual ~Jacobian() = default;

  /**
  \brief Default construction of a Jacobian node is forbidden
  */
  Jacobian() = default;

 private:
  mutable std::shared_ptr<Variable> current_diff_variable_;

  friend class boost::serialization::access;

  template <typename Archive>
  void serialize(Archive& ar, const unsigned version) {
    ar& boost::serialization::base_object<Handle>(*this);
  }
};

}  // namespace node
}  // namespace bertini

#endif