lhsExpressionInterface.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/eventSystem.hpp"
#include "../misc/macros.hpp"
#include "../misc/toConst.hpp"
#include "../tapes/interfaces/fullTapeInterface.hpp"
#include "../traits/expressionTraits.hpp"
#include "../traits/realTraits.hpp"
#include "expressionInterface.hpp"

namespace codi {

  template<typename T_Real, typename T_Gradient, typename T_Tape, typename T_Impl>
  struct LhsExpressionInterface : public ExpressionInterface<T_Real, T_Impl> {
    public:
 
      using Real = CODI_DD(T_Real, double);                  
      using Gradient = CODI_DD(T_Gradient, Real);            
      using Tape = CODI_DD(T_Tape, CODI_DEFAULT_TAPE);       
      using Impl = CODI_DD(T_Impl, LhsExpressionInterface);  
 
      using Base = ExpressionInterface<T_Real, T_Impl>;  
 
      using Identifier = typename Tape::Identifier;       
      using PassiveReal = RealTraits::PassiveReal<Real>;  
 
      LhsExpressionInterface() = default;                                     
      LhsExpressionInterface(LhsExpressionInterface const& other) = default;  
 
      /*******************************************************************************/
 
      Real const& value() const;  
      Real& value();              
 
      Identifier const& getIdentifier() const;  
      Identifier& getIdentifier();  
 
      static Tape& getTape();  

      /*******************************************************************************/

      CODI_INLINE Impl& cast() {
        return static_cast<Impl&>(*this);
      }
      using Base::cast;

      CODI_INLINE Gradient& gradient() {
        return Impl::getTape().gradient(cast().getIdentifier());
      }

      CODI_INLINE Gradient const& gradient() const {
        return toConst(Impl::getTape()).gradient(cast().getIdentifier());
      }

      CODI_INLINE Gradient getGradient() const {
        return cast().gradient();
      }

      CODI_INLINE void setGradient(Gradient const& g) {
        cast().gradient() = g;
      }

      CODI_INLINE Real const& getValue() const {
        return cast().value();
      }

      CODI_INLINE void setValue(Real const& v) {
        cast().value() = v;
      }

      CODI_INLINE Impl& operator=(Real const& rhs) {
        EventSystem<Tape>::notifyStatementPrimalListeners(Impl::getTape(), cast().getValue(), cast().getIdentifier(),
                                                          rhs, EventHints::Statement::Passive);
        Impl::getTape().store(cast(), rhs);
        return cast();
      }

      template<typename U = Real, typename = RealTraits::EnableIfNotPassiveReal<U>>
      CODI_INLINE Impl& operator=(PassiveReal const& rhs) {
        EventSystem<Tape>::notifyStatementPrimalListeners(Impl::getTape(), cast().getValue(), cast().getIdentifier(),
                                                          rhs, EventHints::Statement::Passive);
        Impl::getTape().store(cast(), rhs);
        return cast();
      }

      template<typename Rhs>
      CODI_INLINE Impl& operator=(ExpressionInterface<Real, Rhs> const& rhs) {
        EventSystem<Tape>::notifyStatementPrimalListeners(Impl::getTape(), cast().getValue(), cast().getIdentifier(),
                                                          rhs.cast().getValue(), EventHints::Statement::Expression);
        Impl::getTape().store(cast(), rhs.cast());
        return cast();
      }

      template<typename Rhs, typename U = Real, typename = RealTraits::EnableIfNotPassiveReal<U>>
      CODI_INLINE Impl& operator=(ExpressionInterface<typename U::Real, Rhs> const& rhs) {
        EventSystem<Tape>::notifyStatementPrimalListeners(Impl::getTape(), cast().getValue(), cast().getIdentifier(),
                                                          rhs.cast().getValue(), EventHints::Statement::Passive);
        Impl::getTape().store(cast(), Real(rhs));
        return cast();
      }

      CODI_INLINE Impl& operator=(LhsExpressionInterface const& rhs) {
        EventSystem<Tape>::notifyStatementPrimalListeners(Impl::getTape(), cast().getValue(), cast().getIdentifier(),
                                                          rhs.cast().getValue(), EventHints::Statement::Copy);
        Impl::getTape().store(cast(), rhs);
        return cast();
      }

      template<typename Rhs>
      CODI_INLINE Impl& operator=(LhsExpressionInterface<Real, Gradient, Tape, Rhs> const& rhs) {
        EventSystem<Tape>::notifyStatementPrimalListeners(Impl::getTape(), cast().getValue(), cast().getIdentifier(),
                                                          rhs.cast().getValue(), EventHints::Statement::Copy);
        Impl::getTape().store(cast(), rhs);
        return cast();
      }

      /*******************************************************************************/
 
      static size_t constexpr LinkCount = 0;  
 
    protected:

      CODI_INLINE void init(Real const& newValue, EventHints::Statement statementType) {
        Impl::getTape().initIdentifier(cast().value(), cast().getIdentifier());
        EventSystem<Tape>::notifyStatementPrimalListeners(Impl::getTape(), Real(), Identifier(), newValue,
                                                          statementType);
      }

      CODI_INLINE void destroy() {
        Impl::getTape().destroyIdentifier(cast().value(), cast().getIdentifier());
      }

  };

  template<typename Expr>
  ExpressionTraits::EnableIfLhsExpression<Expr, std::istream>& operator>>(std::istream& stream, Expr& v) {
    typename Expr::Real temp;
 
    stream >> temp;
    v.setValue(temp);
 
    return stream;
  }
 
#ifndef DOXYGEN_DISABLE

  template<typename T_Type>
  struct RealTraits::DataExtraction<T_Type, ExpressionTraits::EnableIfLhsExpression<T_Type>> {
    public:
      using Type = CODI_DD(T_Type, CODI_DEFAULT_LHS_EXPRESSION);  
 
      using Real = typename Type::Real;              
      using Identifier = typename Type::Identifier;  

      CODI_INLINE static Real getValue(Type const& v) {
        return v.getValue();
      }

      CODI_INLINE static Identifier getIdentifier(Type const& v) {
        return v.getIdentifier();
      }

      CODI_INLINE static void setValue(Type& v, Real const& value) {
        v.setValue(value);
      }

      CODI_INLINE static void setIdentifier(Type& v, Identifier const& identifier) {
        v.getIdentifier() = identifier;
      }
  };

  template<typename T_Type>
  struct RealTraits::TapeRegistration<T_Type, ExpressionTraits::EnableIfLhsExpression<T_Type>> {
      using Type = CODI_DD(T_Type, CODI_DEFAULT_LHS_EXPRESSION);  
 
      using Real = typename DataExtraction<Type>::Real;  

      CODI_INLINE static void registerInput(Type& v) {
        Type::getTape().registerInput(v);
      }

      CODI_INLINE static void registerOutput(Type& v) {
        Type::getTape().registerOutput(v);
      }

      CODI_INLINE static Real registerExternalFunctionOutput(Type& v) {
        return Type::getTape().registerExternalFunctionOutput(v);
      }
  };

  template<typename T_Type>
  struct RealTraits::AggregatedTypeTraits<T_Type, ExpressionTraits::EnableIfLhsExpression<T_Type>>
      : RealTraits::ArrayAggregatedTypeTraitsBase<T_Type, T_Type, typename T_Type::Real, 1> {
    public:

      static CODI_INLINE std::string getMathRep() {
        return "()";
      }
  };
#endif
}