parameters.h

#ifndef PARAMETERS_H
#define PARAMETERS_H

#include <deal.II/base/parameter_handler.h>

/**
 * This class declares all parameters, which can be specified in the parameter
 * file. The subsection abut preCICE configurations is directly interlinked
 * to the Adapter class.
 */
namespace Parameters
{
  using namespace dealii;
  /**
   * @brief Time: Specifies simulation time properties
   */
  struct Time
  {
    double      end_time        = 1;
    double      delta_t         = 0.1;
    int         output_interval = 1;
    std::string output_folder   = "";


    void
    add_output_parameters(ParameterHandler &prm);
  };

  /**
   * @brief The System struct keeps material properties and body force contributions
   */
  struct System
  {
    double               nu     = 0.3;
    double               mu     = 1538462;
    double               lambda = -1;
    double               rho    = 1000;
    Tensor<1, 3, double> body_force;

    void
    add_output_parameters(ParameterHandler &prm);
  };


  /**
   * @brief LinearSolver: Specifies linear solver properties
   */
  struct Solver
  {
    std::string  model              = "linear";
    std::string  type_lin           = "Direct";
    double       tol_lin            = 1e-6;
    double       max_iterations_lin = 1;
    unsigned int max_iterations_NR  = 10;
    double       tol_f              = 1e-9;
    double       tol_u              = 1e-6;

    void
    add_output_parameters(ParameterHandler &prm);
  };



  /**
   * @brief Discretization: Specifies parameters for time integration by a
   *        theta scheme and polynomial degree of the FE system
   */
  struct Discretization
  {
    unsigned int poly_degree = 3;
    // For the linear elastic model (theta-scheme)
    double theta = 0.5;
    // For the nonlinear elastic model (Newmark)
    double beta  = 0.25;
    double gamma = 0.5;

    void
    add_output_parameters(ParameterHandler &prm);
  };


  /**
   * @brief PreciceAdapterConfiguration: Specifies preCICE related information.
   *        A lot of these information need to be consistent with the
   *        precice-config.xml file.
   */
  struct PreciceAdapterConfiguration
  {
    std::string scenario         = "FSI3";
    std::string config_file      = "precice-config.xml";
    std::string participant_name = "dealiisolver";
    std::string mesh_name        = "dealii-mesh";
    std::string read_data_name   = "Stress";
    std::string write_data_name  = "Displacement";
    double      flap_location    = 0.0;
    bool        data_consistent  = true;

    void
    add_output_parameters(ParameterHandler &prm);
  };


  struct AllParameters : public Solver,
                         public Discretization,
                         public System,
                         public Time,
                         public PreciceAdapterConfiguration

  {
    AllParameters(const std::string &input_file);
  };
} // namespace Parameters

#endif // PARAMETERS_H