jacobianReuseTape.hpp

/*
 * CoDiPack, a Code Differentiation Package
 *
 * Copyright (C) 2015-2026 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 <algorithm>
#include <fstream>
#include <type_traits>
 
#include "../config.h"
#include "../expressions/lhsExpressionInterface.hpp"
#include "../expressions/logic/compileTimeTraversalLogic.hpp"
#include "../expressions/logic/traversalLogic.hpp"
#include "../misc/macros.hpp"
#include "../traits/expressionTraits.hpp"
#include "data/chunk.hpp"
#include "indices/indexManagerInterface.hpp"
#include "interfaces/editingTapeInterface.hpp"
#include "interfaces/reverseTapeInterface.hpp"
#include "io/tapeReaderWriterInterface.hpp"
#include "jacobianBaseTape.hpp"

namespace codi {

  template<typename T_TapeTypes>
  struct JacobianReuseTape
      : public JacobianBaseTape<T_TapeTypes, JacobianReuseTape<T_TapeTypes>>,
        public EditingTapeInterface<typename JacobianBaseTape<T_TapeTypes, JacobianReuseTape<T_TapeTypes>>::Position> {
    public:
 
      using TapeTypes = CODI_DD(T_TapeTypes,
                                CODI_T(JacobianTapeTypes<double, double, IndexManagerInterface<int>,
                                                         DefaultChunkedData>));  
 
      using Base = JacobianBaseTape<T_TapeTypes, JacobianReuseTape>;  
      friend Base;  
 
      using Real = typename TapeTypes::Real;                              
      using Gradient = typename TapeTypes::Gradient;                      
      using IndexManager = typename TapeTypes::IndexManager;              
      using Identifier = typename TapeTypes::Identifier;                  
      using ActiveTypeTapeData = typename TapeTypes::ActiveTypeTapeData;  
      using Position = typename Base::Position;                           
      using StatementData = typename TapeTypes::StatementData;            
 
      CODI_STATIC_ASSERT(!IndexManager::IsLinear, "This class requires an index manager with a reuse scheme.");

      JacobianReuseTape() : Base() {}
 
      /*******************************************************************************/
 
      using Base::clearAdjoints;

      void clearAdjoints(Position const& start, Position const& end,
                         AdjointsManagement adjointsManagement = AdjointsManagement::Automatic) {
        if (AdjointsManagement::Automatic == adjointsManagement) {
          this->adjoints.beginUse();
        }
 
        Identifier adjointsSize = (Identifier)this->adjoints.size();
 
        auto clearFunc = [&adjointsSize, this](Identifier* index, Config::ArgumentSize* stmtSize) {
          CODI_UNUSED(stmtSize);
 
          if (*index < adjointsSize) {
            this->adjoints[*index] = Gradient();
          }
        };
 
        using StmtPosition = typename StatementData::Position;
        StmtPosition startStmt = this->llfByteData.template extractPosition<StmtPosition>(start);
        StmtPosition endStmt = this->llfByteData.template extractPosition<StmtPosition>(end);
 
        this->statementData.forEachReverse(startStmt, endStmt, clearFunc);
 
        if (AdjointsManagement::Automatic == adjointsManagement) {
          this->adjoints.endUse();
        }
      }

      template<typename AdjointVector>
      void clearCustomAdjoints(Position const& start, Position const& end, AdjointVector&& data) {
        auto clearFunc = [&data](Identifier* index, Config::ArgumentSize* stmtSize) {
          CODI_UNUSED(stmtSize);
          data[*index] = Gradient();
        };
 
        using StmtPosition = typename StatementData::Position;
        StmtPosition startStmt = this->llfByteData.template extractPosition<StmtPosition>(start);
        StmtPosition endStmt = this->llfByteData.template extractPosition<StmtPosition>(end);
 
        this->statementData.forEachReverse(startStmt, endStmt, clearFunc);
      }

 
    protected:
 
      /*******************************************************************************/

      CODI_INLINE void pushStmtData(Identifier const& index, Config::ArgumentSize const& numberOfArguments) {
        this->statementData.pushData(index, numberOfArguments);
      }

      template<typename AdjointVector>
      CODI_INLINE static void internalEvaluateForward_EvalStatements(
          /* data from call */
          JacobianReuseTape& tape, AdjointVector&& adjointVector,
          /* data from low level function byte data vector */
          size_t& curLLFByteDataPos, size_t const& endLLFByteDataPos, char* dataPtr,
          /* data from low level function info data vector */
          size_t& curLLFInfoDataPos, size_t const& endLLFInfoDataPos, Config::LowLevelFunctionToken* const tokenPtr,
          Config::LowLevelFunctionDataSize* const dataSizePtr,
          /* data from jacobian vector */
          size_t& curJacobianPos, size_t const& endJacobianPos, Real const* const rhsJacobians,
          Identifier const* const rhsIdentifiers,
          /* data from statement vector */
          size_t& curStmtPos, size_t const& endStmtPos, Identifier const* const lhsIdentifiers,
          Config::ArgumentSize const* const numberOfJacobians) {
        CODI_UNUSED(endJacobianPos, endLLFByteDataPos, endLLFInfoDataPos);
 
        using Adjoint = AdjointVectorTraits::Gradient<AdjointVector>;
 
        typename Base::template VectorAccess<AdjointVector> vectorAccess(adjointVector);
 
        while (curStmtPos < endStmtPos) CODI_Likely {
          Config::ArgumentSize const argsSize = numberOfJacobians[curStmtPos];
 
          if (Config::StatementLowLevelFunctionTag == argsSize) CODI_Unlikely {
            Base::template callLowLevelFunction<LowLevelFunctionEntryCallKind::Forward>(
                tape, true, curLLFByteDataPos, dataPtr, curLLFInfoDataPos, tokenPtr, dataSizePtr, &vectorAccess);
          } else CODI_Likely {
            Adjoint lhsAdjoint = Adjoint();
            Base::template incrementTangents<AdjointVector>(adjointVector, lhsAdjoint, argsSize, curJacobianPos,
                                                            rhsJacobians, rhsIdentifiers);
 
            adjointVector[lhsIdentifiers[curStmtPos]] = lhsAdjoint;
 
            EventSystem<JacobianReuseTape>::notifyStatementEvaluateListeners(
                tape, lhsIdentifiers[curStmtPos], GradientTraits::dim<Adjoint>(),
                GradientTraits::toArray(lhsAdjoint).data());
          }
 
          curStmtPos += 1;
        }
      }

      template<typename AdjointVector>
      CODI_INLINE static void internalEvaluateReverse_EvalStatements(
          /* data from call */
          JacobianReuseTape& tape, AdjointVector&& adjointVector,
          /* data from low level function byte data vector */
          size_t& curLLFByteDataPos, size_t const& endLLFByteDataPos, char* dataPtr,
          /* data from low level function info data vector */
          size_t& curLLFInfoDataPos, size_t const& endLLFInfoDataPos, Config::LowLevelFunctionToken* const tokenPtr,
          Config::LowLevelFunctionDataSize* const dataSizePtr,
          /* data from jacobianData */
          size_t& curJacobianPos, size_t const& endJacobianPos, Real const* const rhsJacobians,
          Identifier const* const rhsIdentifiers,
          /* data from statementData */
          size_t& curStmtPos, size_t const& endStmtPos, Identifier const* const lhsIdentifiers,
          Config::ArgumentSize const* const numberOfJacobians) {
        CODI_UNUSED(endJacobianPos, endLLFByteDataPos, endLLFInfoDataPos);
 
        using Adjoint = AdjointVectorTraits::Gradient<AdjointVector>;
 
        typename Base::template VectorAccess<AdjointVector> vectorAccess(adjointVector);
 
        while (curStmtPos > endStmtPos) CODI_Likely {
          curStmtPos -= 1;
 
          Config::ArgumentSize const argsSize = numberOfJacobians[curStmtPos];
 
          if (Config::StatementLowLevelFunctionTag == argsSize) CODI_Unlikely {
            Base::template callLowLevelFunction<LowLevelFunctionEntryCallKind::Reverse>(
                tape, false, curLLFByteDataPos, dataPtr, curLLFInfoDataPos, tokenPtr, dataSizePtr, &vectorAccess);
          } else CODI_Likely {
            Adjoint const lhsAdjoint = adjointVector[lhsIdentifiers[curStmtPos]];
 
            EventSystem<JacobianReuseTape>::notifyStatementEvaluateListeners(
                tape, lhsIdentifiers[curStmtPos], GradientTraits::dim<Adjoint>(),
                GradientTraits::toArray(lhsAdjoint).data());
 
            adjointVector[lhsIdentifiers[curStmtPos]] = Adjoint();
            Base::incrementAdjoints(adjointVector, lhsAdjoint, argsSize, curJacobianPos, rhsJacobians, rhsIdentifiers);
          }
        }
      }

      template<typename TapeTypes>
      CODI_INLINE static void internalWriteTape(
          /* file interface pointer*/
          codi::TapeWriterInterface<TapeTypes>* writer,
          /* data from low level function byte data vector */
          size_t& curLLFByteDataPos, size_t const& endLLFByteDataPos, char* dataPtr,
          /* data from low level function info data vector */
          size_t& curLLFInfoDataPos, size_t const& endLLFInfoDataPos, Config::LowLevelFunctionToken* const tokenPtr,
          Config::LowLevelFunctionDataSize* const dataSizePtr,
          /* data from jacobianData */
          size_t& curJacobianPos, size_t const& endJacobianPos, Real const* const rhsJacobians,
          Identifier const* const rhsIdentifiers,
          /* data from statementData */
          size_t& curStmtPos, size_t const& endStmtPos, Identifier const* const lhsIdentifiers,
          Config::ArgumentSize const* const numberOfJacobians) {
        CODI_UNUSED(endLLFByteDataPos, endLLFInfoDataPos, endJacobianPos);
        Identifier curLhsIdentifier;
        Config::ArgumentSize curNumberOfJacobians;
 
        ByteDataView dataView = {};
        LowLevelFunctionEntry<JacobianReuseTape, Real, Identifier> const* func = nullptr;
 
        while (curStmtPos < endStmtPos) CODI_Likely {
          curLhsIdentifier = lhsIdentifiers[curStmtPos];
          curNumberOfJacobians = numberOfJacobians[curStmtPos];
          if (Config::StatementLowLevelFunctionTag == curNumberOfJacobians) CODI_Unlikely {
            Base::prepareLowLevelFunction(true, curLLFByteDataPos, dataPtr, curLLFInfoDataPos, tokenPtr, dataSizePtr,
                                          dataView, func);
            writer->writeLowLevelFunction(func, dataView);
          } else CODI_Likely {
            writer->writeStatement(curLhsIdentifier, curJacobianPos, rhsJacobians, rhsIdentifiers,
                                   curNumberOfJacobians);
            curJacobianPos += numberOfJacobians[curStmtPos];
          }
          curStmtPos += 1;
        }
      }

 
    public:
 
      /*******************************************************************************/
 
      using Base::iterateForward;
      template<typename Callbacks>
      CODI_INLINE void iterateForward(Callbacks&& callbacks, Position start, Position end) {
        auto evalFunc = [&callbacks](
                            /* data from call */
                            JacobianReuseTape& tape,
                            /* data from low level function byte data vector */
                            size_t& curLLFByteDataPos, size_t const& endLLFByteDataPos, char* dataPtr,
                            /* data from low level function info data vector */
                            size_t& curLLFInfoDataPos, size_t const& endLLFInfoDataPos,
                            Config::LowLevelFunctionToken* const tokenPtr,
                            Config::LowLevelFunctionDataSize* const dataSizePtr,
                            /* data from jacobian vector */
                            size_t& curJacobianPos, size_t const& endJacobianPos, Real* const rhsJacobians,
                            Identifier* const rhsIdentifiers,
                            /* data from statement vector */
                            size_t& curStmtPos, size_t const& endStmtPos, Identifier* const lhsIdentifiers,
                            Config::ArgumentSize const* const numberOfJacobians) CODI_LAMBDA_INLINE {
          CODI_UNUSED(tape, endJacobianPos, endLLFByteDataPos, endLLFInfoDataPos);
 
          ByteDataView dataView = {};
          LowLevelFunctionEntry<JacobianReuseTape, Real, Identifier> const* func = nullptr;
 
          while (curStmtPos < endStmtPos) CODI_Likely {
            Config::ArgumentSize const argsSize = numberOfJacobians[curStmtPos];
 
            if (Config::StatementLowLevelFunctionTag == argsSize) CODI_Unlikely {
              Base::prepareLowLevelFunction(true, curLLFByteDataPos, dataPtr, curLLFInfoDataPos, tokenPtr, dataSizePtr,
                                            dataView, func);
              callbacks.handleLowLevelFunction(*func, dataView);
            } else CODI_Likely {
              callbacks.handleStatement(lhsIdentifiers[curStmtPos], argsSize, &rhsJacobians[curJacobianPos],
                                        &rhsIdentifiers[curJacobianPos]);
 
              curJacobianPos += argsSize;
            }
 
            curStmtPos += 1;
          }
        };
 
        Base::llfByteData.evaluateForward(start, end, evalFunc, *this);
      }
 
      using Base::iterateReverse;
      template<typename Callbacks>
      CODI_INLINE void iterateReverse(Callbacks&& callbacks, Position start, Position end) {
        auto evalFunc = [&callbacks](
                            /* data from call */
                            JacobianReuseTape& tape,
                            /* data from low level function byte data vector */
                            size_t& curLLFByteDataPos, size_t const& endLLFByteDataPos, char* dataPtr,
                            /* data from low level function info data vector */
                            size_t& curLLFInfoDataPos, size_t const& endLLFInfoDataPos,
                            Config::LowLevelFunctionToken* const tokenPtr,
                            Config::LowLevelFunctionDataSize* const dataSizePtr,
                            /* data from jacobian vector */
                            size_t& curJacobianPos, size_t const& endJacobianPos, Real* const rhsJacobians,
                            Identifier* const rhsIdentifiers,
                            /* data from statement vector */
                            size_t& curStmtPos, size_t const& endStmtPos, Identifier* const lhsIdentifiers,
                            Config::ArgumentSize const* const numberOfJacobians) CODI_LAMBDA_INLINE {
          CODI_UNUSED(tape, endJacobianPos, endLLFByteDataPos, endLLFInfoDataPos);
 
          ByteDataView dataView = {};
          LowLevelFunctionEntry<JacobianReuseTape, Real, Identifier> const* func = nullptr;
 
          while (curStmtPos > endStmtPos) CODI_Likely {
            curStmtPos -= 1;
 
            Config::ArgumentSize const argsSize = numberOfJacobians[curStmtPos];
 
            if (Config::StatementLowLevelFunctionTag == argsSize) CODI_Unlikely {
              Base::prepareLowLevelFunction(false, curLLFByteDataPos, dataPtr, curLLFInfoDataPos, tokenPtr, dataSizePtr,
                                            dataView, func);
              callbacks.handleLowLevelFunction(*func, dataView);
            } else CODI_Likely {
              curJacobianPos -= argsSize;
 
              callbacks.handleStatement(lhsIdentifiers[curStmtPos], argsSize, &rhsJacobians[curJacobianPos],
                                        &rhsIdentifiers[curJacobianPos]);
            }
          }
        };
 
        Base::llfByteData.evaluateReverse(start, end, evalFunc, *this);
      }

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

      CODI_INLINE void erase(Position const& start, Position const& end) {
        JacobianReuseTape emptyTape;
        erase(start, end, emptyTape);
      }
 
      // clang-format off
      // clang-format on
      CODI_INLINE void erase(Position const& start, Position const& end, JacobianReuseTape& emptyTape) {
        // Store the tail after the part to be erased in the helper tape.
        emptyTape.append(*this, end, this->getPosition());
 
        // Reset the tape to before the erased part and re-append the tail. This accounts for external function position
        // correction.
 
        // Do not delete external function data for the part to be reappended.
        this->llfByteData.resetTo(end);
        clearAdjoints(end, this->getPosition());
 
        // Delete external function data in the part to be erased.
        this->resetTo(start);
 
        this->append(emptyTape, emptyTape.getZeroPosition(), emptyTape.getPosition());
 
        // Do not delete external function data in the helper tape.
        emptyTape.llfByteData.reset();
      }

      CODI_INLINE void append(JacobianReuseTape& srcTape, Position const& start, Position const& end) {
        srcTape.llfByteData.evaluateForward(start, end, JacobianReuseTape::internalAppend, this);
      }

      template<typename Func>
      void editIdentifiers(Func&& modifyIdentifier, Position const& start, Position const& end) {
        auto evalFunc = [&modifyIdentifier](
                            /* data from low level function byte data vector */
                            size_t&, size_t const&, char*,
                            /* data from low level function info data vector */
                            size_t&, size_t const&, Config::LowLevelFunctionToken* const,
                            Config::LowLevelFunctionDataSize* const,
                            /* data from jacobianData */
                            size_t& curJacobianPos, size_t const&, Real const* const, Identifier* const rhsIdentifiers,
                            /* data from statementData */
                            size_t& curStmtPos, size_t const& endStmtPos, Identifier* const lhsIdentifiers,
                            Config::ArgumentSize const* const numberOfJacobians) {
          while (curStmtPos < endStmtPos) CODI_Likely {
            Config::ArgumentSize const argsSize = numberOfJacobians[curStmtPos];
 
            if (Config::StatementLowLevelFunctionTag != argsSize) CODI_Likely {  // skip low-level functions
              modifyIdentifier(lhsIdentifiers[curStmtPos]);
 
              size_t endJacobianPos = curJacobianPos + argsSize;
              while (curJacobianPos < endJacobianPos) CODI_Likely {
                modifyIdentifier(rhsIdentifiers[curJacobianPos]);
                curJacobianPos += 1;
              }
            }
 
            curStmtPos += 1;
          }
        };
 
        Base::llfByteData.evaluateForward(start, end, evalFunc);
      }

 
    private:
 
      static CODI_INLINE void internalAppend(
          /* data from call */
          JacobianReuseTape* dstTape,
          /* data from low level function byte data vector */
          size_t& curLLFByteDataPos, size_t const& endLLFByteDataPos, char* dataPtr,
          /* data from low level function info data vector */
          size_t& curLLFInfoDataPos, size_t const& endLLFInfoDataPos, Config::LowLevelFunctionToken* const tokenPtr,
          Config::LowLevelFunctionDataSize* const dataSizePtr,
          /* data from jacobianData */
          size_t& curJacobianPos, size_t const& endJacobianPos, Real const* const rhsJacobians,
          Identifier const* const rhsIdentifiers,
          /* data from statementData */
          size_t& curStmtPos, size_t const& endStmtPos, Identifier const* const lhsIdentifiers,
          Config::ArgumentSize const* const numberOfJacobians) {
        CODI_UNUSED(endLLFByteDataPos, endLLFInfoDataPos, endJacobianPos);
 
        while (curStmtPos < endStmtPos) {
          Config::ArgumentSize const argsSize = numberOfJacobians[curStmtPos];
          if (Config::StatementLowLevelFunctionTag == argsSize) CODI_Unlikely {
            Config::LowLevelFunctionToken token = tokenPtr[curLLFInfoDataPos];
            size_t dataSize = dataSizePtr[curLLFInfoDataPos];
 
            // Create the store on the new tape.
            ByteDataView dstDataStore = {};
            dstTape->pushLowLevelFunction(token, dataSize, dstDataStore);
 
            // Copy the data.
            dstDataStore.write(&dataPtr[curLLFByteDataPos], dataSize);
 
            curLLFInfoDataPos += 1;
            curLLFByteDataPos += dataSize;
          } else CODI_Likely {
            // Manual statement push.
            dstTape->statementData.reserveItems(1);
            dstTape->jacobianData.reserveItems(numberOfJacobians[curStmtPos]);
 
            dstTape->pushStmtData(lhsIdentifiers[curStmtPos], numberOfJacobians[curStmtPos]);
            size_t curJacobianEnd = curJacobianPos + numberOfJacobians[curStmtPos];
 
            while (curJacobianPos < curJacobianEnd) {
              dstTape->jacobianData.pushData(rhsJacobians[curJacobianPos], rhsIdentifiers[curJacobianPos]);
              ++curJacobianPos;
            }
          }
 
          ++curStmtPos;
        }
      }
  };
}