text: /**
   * \file
   * \copyright
   * Copyright (c) 2012-2019, OpenGeoSys Community (http://www.opengeosys.org)
   *            Distributed under a Modified BSD License.
   *              See accompanying file LICENSE.txt or
   *              http://www.opengeosys.org/project/license
   *
   */
  
  #pragma once
  
  #include "ProcessLib/Process.h"
  #include "HydroMechanicsProcessData.h"
  #include "LocalAssemblerInterface.h"
  
  namespace ProcessLib
  {
  namespace HydroMechanics
  {
  /// Linear kinematics poro-mechanical/biphasic (fluid-solid mixture) model.
  ///
  /// The mixture momentum balance and the mixture mass balance are solved under
  /// fully saturated conditions.
  template <int DisplacementDim>
  class HydroMechanicsProcess final : public Process
  {
  public:
      HydroMechanicsProcess(
          std::string name,
          MeshLib::Mesh& mesh,
          std::unique_ptr<ProcessLib::AbstractJacobianAssembler>&&
              jacobian_assembler,
          std::vector<std::unique_ptr<ParameterLib::ParameterBase>> const&
              parameters,
          unsigned const integration_order,
          std::vector<std::vector<std::reference_wrapper<ProcessVariable>>>&&
              process_variables,
          HydroMechanicsProcessData<DisplacementDim>&& process_data,
          SecondaryVariableCollection&& secondary_variables,
          bool const use_monolithic_scheme);
  
      //! \name ODESystem interface
      //! @{
  
      bool isLinear() const override;
      //! @}
  
      /**
       * Get the size and the sparse pattern of the global matrix in order to
       * create the global matrices and vectors for the system equations of this
       * process.
       *
       * @param process_id Process ID. If the monolithic scheme is applied,
       *                               process_id = 0. For the staggered scheme,
       *                               process_id = 0 represents the
       *                               hydraulic (H) process, while process_id = 1
       *                               represents the mechanical (M) process.
       * @return Matrix specifications including size and sparse pattern.
       */
      MathLib::MatrixSpecifications getMatrixSpecifications(
          const int process_id) const override;
  
  private:
      using LocalAssemblerIF = LocalAssemblerInterface<DisplacementDim>;
  
      void constructDofTable() override;
  
      void initializeConcreteProcess(
          NumLib::LocalToGlobalIndexMap const& dof_table,
          MeshLib::Mesh const& mesh,
          unsigned const integration_order) override;
  
      void initializeBoundaryConditions() override;
  
      void assembleConcreteProcess(const double t, double const /*dt*/,
                                   std::vector<GlobalVector*> const& x,
                                   int const process_id, GlobalMatrix& M,
                                   GlobalMatrix& K, GlobalVector& b) override;
  
      void assembleWithJacobianConcreteProcess(
          const double t, double const /*dt*/,
          std::vector<GlobalVector*> const& x, GlobalVector const& xdot,
          const double dxdot_dx, const double dx_dx, int const process_id,
          GlobalMatrix& M, GlobalMatrix& K, GlobalVector& b,
          GlobalMatrix& Jac) override;
  
      void preTimestepConcreteProcess(std::vector<GlobalVector*> const& x,
                                      double const t, double const dt,
                                      const int process_id) override;
  
      void postTimestepConcreteProcess(std::vector<GlobalVector*> const& x,
                                       const double t, const double delta_t,
                                       int const process_id) override;
  
      void postNonLinearSolverConcreteProcess(GlobalVector const& x,
                                              const double t, double const dt,
                                              int const process_id) override;
  
      NumLib::LocalToGlobalIndexMap const& getDOFTable(
          const int process_id) const override;
  
  private:
      std::vector<MeshLib::Node*> _base_nodes;
      std::unique_ptr<MeshLib::MeshSubset const> _mesh_subset_base_nodes;
      HydroMechanicsProcessData<DisplacementDim> _process_data;
  
      std::vector<std::unique_ptr<LocalAssemblerIF>> _local_assemblers;
  
      std::unique_ptr<NumLib::LocalToGlobalIndexMap>
          _local_to_global_index_map_single_component;
  
      /// Local to global index mapping for base nodes, which is used for linear
      /// interpolation for pressure in the staggered scheme.
      std::unique_ptr<NumLib::LocalToGlobalIndexMap>
          _local_to_global_index_map_with_base_nodes;
  
      /// Sparsity pattern for the flow equation, and it is initialized only if
      /// the staggered scheme is used.
      GlobalSparsityPattern _sparsity_pattern_with_linear_element;
  
      /// Solutions of the previous time step
      std::array<std::unique_ptr<GlobalVector>, 2> _xs_previous_timestep;
  
      void computeSecondaryVariableConcrete(const double t, GlobalVector const& x,
                                            const int process_id) override;
      /**
       * @copydoc ProcessLib::Process::getDOFTableForExtrapolatorData()
       */
      std::tuple<NumLib::LocalToGlobalIndexMap*, bool>
          getDOFTableForExtrapolatorData() const override;
  
      /// Check whether the process represented by \c process_id is/has
      /// mechanical process. In the present implementation, the mechanical
      /// process has process_id == 1 in the staggered scheme.
      bool hasMechanicalProcess(int const process_id) const
      {
          return _use_monolithic_scheme || process_id == 1;
      }
  
      MeshLib::PropertyVector<double>* _nodal_forces = nullptr;
      MeshLib::PropertyVector<double>* _hydraulic_flow = nullptr;
  };
  
  extern template class HydroMechanicsProcess<2>;
  extern template class HydroMechanicsProcess<3>;
  
  }  // namespace HydroMechanics
  }  // namespace ProcessLib
  