riemann_solver.h

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//
// SPDX-License-Identifier: Apache-2.0
// [LANL Copyright Statement]
// Copyright (C) 2023 - 2024 by the ryujin authors
// Copyright (C) 2023 - 2024 by Triad National Security, LLC
//
 
#pragma once
 
#include "hyperbolic_system.h"
 
#include <simd.h>
 
#include <deal.II/base/point.h>
#include <deal.II/base/tensor.h>
 
namespace ryujin
{
  namespace ShallowWater
  {
    template <typename ScalarNumber = double>
    class RiemannSolverParameters : public dealii::ParameterAcceptor
    {
    public:
      RiemannSolverParameters(const std::string &subsection = "/RiemannSolver")
          : ParameterAcceptor(subsection)
      {
      }
    };
 
 
    template <int dim, typename Number = double>
    class RiemannSolver
    {
    public:
 
      using View = HyperbolicSystemView<dim, Number>;
 
      using ScalarNumber = typename View::ScalarNumber;
 
      static constexpr auto problem_dimension = View::problem_dimension;
 
      using state_type = typename View::state_type;
 
      static constexpr unsigned int riemann_data_size = 3;
 
      using primitive_type = typename std::array<Number, riemann_data_size>;
 
      using precomputed_type = typename View::precomputed_type;
 
      using PrecomputedVector = typename View::PrecomputedVector;
 
      using Parameters = RiemannSolverParameters<ScalarNumber>;
 
 
 
      RiemannSolver(const HyperbolicSystem &hyperbolic_system,
                    const Parameters &parameters,
                    const PrecomputedVector &precomputed_values)
          : hyperbolic_system(hyperbolic_system)
          , parameters(parameters)
          , precomputed_values(precomputed_values)
      {
      }
 
      Number compute(const primitive_type &riemann_data_i,
                     const primitive_type &riemann_data_j) const;
 
      Number compute(const state_type &U_i,
                     const state_type &U_j,
                     const unsigned int i,
                     const unsigned int *js,
                     const dealii::Tensor<1, dim, Number> &n_ij) const;
 
    protected:
 
 
      Number f(const primitive_type &primitive_state,
               const Number &h_star) const;
 
      Number phi(const primitive_type &riemann_data_i,
                 const primitive_type &riemann_data_j,
                 const Number &h) const;
 
      Number lambda1_minus(const primitive_type &riemann_data,
                           const Number h_star) const;
 
      Number lambda3_plus(const primitive_type &riemann_data,
                          const Number h_star) const;
 
      Number compute_lambda(const primitive_type &riemann_data_i,
                            const primitive_type &riemann_data_j,
                            const Number h_star) const;
 
    public:
      Number compute_h_star(const primitive_type &riemann_data_i,
                            const primitive_type &riemann_data_j) const;
 
    protected:
      primitive_type
      riemann_data_from_state(const state_type &U,
                              const dealii::Tensor<1, dim, Number> &n_ij) const;
 
    private:
      const HyperbolicSystem &hyperbolic_system;
      const Parameters &parameters;
      const PrecomputedVector &precomputed_values;
    };
  } // namespace ShallowWater
} // namespace ryujin