constantExpression.hpp

/*
 * CoDiPack, a Code Differentiation Package
 *
 * Copyright (C) 2015-2025 Chair for Scientific Computing (SciComp), University of Kaiserslautern-Landau
 * Homepage: http://scicomp.rptu.de
 * Contact:  Prof. Nicolas R. Gauger (codi@scicomp.uni-kl.de)
 *
 * Lead developers: Max Sagebaum, Johannes Blühdorn (SciComp, University of Kaiserslautern-Landau)
 *
 * This file is part of CoDiPack (http://scicomp.rptu.de/software/codi).
 *
 * CoDiPack 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.
 *
 * CoDiPack 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 CoDiPack.
 * If not, see <http://www.gnu.org/licenses/>.
 *
 * For other licensing options please contact us.
 *
 * Authors:
 *  - SciComp, University of Kaiserslautern-Landau:
 *    - Max Sagebaum
 *    - Johannes Blühdorn
 *    - Former members:
 *      - Tim Albring
 */
#pragma once
 
#include "../config.h"
#include "../misc/macros.hpp"
#include "expressionInterface.hpp"
#include "logic/nodeInterface.hpp"
#include "logic/traversalLogic.hpp"
 
namespace codi {
 
  template<typename T_StoreData>
  struct ConstantDataConversion {
    public:
 
      using StoreData = CODI_DD(T_StoreData, double);  
      using ArgumentData = StoreData;                  
 
      static ArgumentData const& fromDataStore(StoreData const& v) {
        return v;
      }
 
      static StoreData const& toDataStore(StoreData const& v) {
        return v;
      }
  };
 
  template<typename T_Real, template<typename> class T_ConversionOperator = ConstantDataConversion>
  struct ConstantExpression : public ExpressionInterface<T_Real, ConstantExpression<T_Real, T_ConversionOperator>> {
    public:
 
      using Real = T_Real;  
 
      template<typename T>
      using ConversionOperator = CODI_DD(CODI_T(T_ConversionOperator<T>), CODI_T(ConstantDataConversion<T>));
 
    private:
      Real primalValue;
 
    public:
 
      CODI_INLINE ConstantExpression(Real const& v) : primalValue(v) {}
 
      /*******************************************************************************/
 
      using StoreAs = ConstantExpression;  
      using ActiveResult = void;           
 
      CODI_INLINE Real const& getValue() const {
        return primalValue;
      }
 
      template<size_t argNumber>
      CODI_INLINE Real getJacobian() const {
        return Real();
      }
 
      /*******************************************************************************/
 
      static bool constexpr EndPoint = true;  
 
      template<typename Logic, typename... Args>
      CODI_INLINE void forEachLink(TraversalLogic<Logic>& logic, Args&&... args) const {
        CODI_UNUSED(logic, args...);
      }
 
      template<typename Logic, typename... Args>
      CODI_INLINE static typename Logic::ResultType constexpr forEachLinkConstExpr(Args&&... CODI_UNUSED_ARG(args)) {
        return Logic::NeutralElement;
      }
 
  };
}