Line data    Source code

       1           0 : // Distributed under the MIT License.
       2             : // See LICENSE.txt for details.
       3             : 
       4             : #pragma once
       5             : 
       6             : #include <cstddef>
       7             : #include <pup.h>
       8             : 
       9             : #include "DataStructures/CachedTempBuffer.hpp"
      10             : #include "DataStructures/DataBox/Prefixes.hpp"
      11             : #include "DataStructures/DataVector.hpp"
      12             : #include "DataStructures/TaggedTuple.hpp"
      13             : #include "DataStructures/Tensor/Tensor.hpp"
      14             : #include "Elliptic/Systems/Poisson/Tags.hpp"
      15             : #include "NumericalAlgorithms/LinearOperators/PartialDerivatives.hpp"
      16             : #include "NumericalAlgorithms/Spectral/Mesh.hpp"
      17             : #include "Options/String.hpp"
      18             : #include "PointwiseFunctions/InitialDataUtilities/AnalyticSolution.hpp"
      19             : #include "Utilities/ContainerHelpers.hpp"
      20             : #include "Utilities/Gsl.hpp"
      21             : #include "Utilities/TMPL.hpp"
      22             : 
      23             : namespace Poisson::Solutions {
      24             : 
      25             : namespace detail {
      26             : template <typename DataType, size_t Dim>
      27             : struct MoustacheVariables {
      28             :   using Cache = CachedTempBuffer<
      29             :       Tags::Field<DataType>,
      30             :       ::Tags::deriv<Tags::Field<DataType>, tmpl::size_t<Dim>, Frame::Inertial>,
      31             :       ::Tags::Flux<Tags::Field<DataType>, tmpl::size_t<Dim>, Frame::Inertial>,
      32             :       ::Tags::FixedSource<Tags::Field<DataType>>>;
      33             : 
      34             :   const tnsr::I<DataType, Dim>& x;
      35             : 
      36             :   void operator()(gsl::not_null<Scalar<DataType>*> field,
      37             :                   gsl::not_null<Cache*> cache,
      38             :                   Tags::Field<DataType> /*meta*/) const;
      39             :   void operator()(gsl::not_null<tnsr::i<DataType, Dim>*> field_gradient,
      40             :                   gsl::not_null<Cache*> cache,
      41             :                   ::Tags::deriv<Tags::Field<DataType>, tmpl::size_t<Dim>,
      42             :                                 Frame::Inertial> /*meta*/) const;
      43             :   void operator()(gsl::not_null<tnsr::I<DataType, Dim>*> flux_for_field,
      44             :                   gsl::not_null<Cache*> cache,
      45             :                   ::Tags::Flux<Tags::Field<DataType>, tmpl::size_t<Dim>,
      46             :                                Frame::Inertial> /*meta*/) const;
      47             :   void operator()(gsl::not_null<Scalar<DataType>*> fixed_source_for_field,
      48             :                   gsl::not_null<Cache*> cache,
      49             :                   ::Tags::FixedSource<Tags::Field<DataType>> /*meta*/) const;
      50             : };
      51             : }  // namespace detail
      52             : 
      53             : /*!
      54             :  * \brief A solution to the Poisson equation with a discontinuous first
      55             :  * derivative.
      56             :  *
      57             :  * \details This implements the solution \f$u(x,y)=x\left(1-x\right)
      58             :  * y\left(1-y\right)\left(\left(x-\frac{1}{2}\right)^2+\left(y-
      59             :  * \frac{1}{2}\right)^2\right)^\frac{3}{2}\f$ to the Poisson equation
      60             :  * in two dimensions, and
      61             :  * \f$u(x)=x\left(1-x\right)\left|x-\frac{1}{2}\right|^3\f$ in one dimension.
      62             :  * Their boundary conditions vanish on the square \f$[0,1]^2\f$ or interval
      63             :  * \f$[0,1]\f$, respectively.
      64             :  *
      65             :  * The corresponding source \f$f=-\Delta u\f$ has a discontinuous first
      66             :  * derivative at \f$\frac{1}{2}\f$. This accomplishes two things:
      67             :  *
      68             :  * - It makes it useful to test the convergence behaviour of our elliptic DG
      69             :  * solver.
      70             :  * - It makes it look like a moustache (at least in 1D).
      71             :  *
      72             :  * This solution is taken from \cite Stamm2010.
      73             :  */
      74             : template <size_t Dim>
      75           1 : class Moustache : public elliptic::analytic_data::AnalyticSolution {
      76             :  public:
      77           0 :   using options = tmpl::list<>;
      78           0 :   static constexpr Options::String help{
      79             :       "A solution with a discontinuous first derivative of its source at 1/2 "
      80             :       "that also happens to look like a moustache. It vanishes at zero and one "
      81             :       "in each dimension"};
      82             : 
      83           0 :   Moustache() = default;
      84           0 :   Moustache(const Moustache&) = default;
      85           0 :   Moustache& operator=(const Moustache&) = default;
      86           0 :   Moustache(Moustache&&) = default;
      87           0 :   Moustache& operator=(Moustache&&) = default;
      88           0 :   ~Moustache() override = default;
      89           0 :   std::unique_ptr<elliptic::analytic_data::AnalyticSolution> get_clone()
      90             :       const override {
      91             :     return std::make_unique<Moustache>(*this);
      92             :   }
      93             : 
      94             :   /// \cond
      95             :   explicit Moustache(CkMigrateMessage* m)
      96             :       : elliptic::analytic_data::AnalyticSolution(m) {}
      97             :   using PUP::able::register_constructor;
      98             :   WRAPPED_PUPable_decl_template(Moustache);  // NOLINT
      99             :   /// \endcond
     100             : 
     101             :   template <typename DataType, typename... RequestedTags>
     102           0 :   tuples::TaggedTuple<RequestedTags...> variables(
     103             :       const tnsr::I<DataType, Dim>& x,
     104             :       tmpl::list<RequestedTags...> /*meta*/) const {
     105             :     using VarsComputer = detail::MoustacheVariables<DataType, Dim>;
     106             :     typename VarsComputer::Cache cache{get_size(*x.begin())};
     107             :     const VarsComputer computer{x};
     108             :     return {cache.get_var(computer, RequestedTags{})...};
     109             :   }
     110             : 
     111             :   template <typename... RequestedTags>
     112           0 :   tuples::TaggedTuple<RequestedTags...> variables(
     113             :       const tnsr::I<DataVector, Dim>& x, const Mesh<Dim>& /*mesh*/,
     114             :       const InverseJacobian<DataVector, Dim, Frame::ElementLogical,
     115             :                             Frame::Inertial>& /*inv_jacobian*/,
     116             :       tmpl::list<RequestedTags...> meta) const {
     117             :     return variables(x, meta);
     118             :   }
     119             : };
     120             : 
     121             : /// \cond
     122             : template <size_t Dim>
     123             : PUP::able::PUP_ID Moustache<Dim>::my_PUP_ID = 0;  // NOLINT
     124             : /// \endcond
     125             : 
     126             : template <size_t Dim>
     127           0 : constexpr bool operator==(const Moustache<Dim>& /*lhs*/,
     128             :                           const Moustache<Dim>& /*rhs*/) {
     129             :   return true;
     130             : }
     131             : 
     132             : template <size_t Dim>
     133           0 : constexpr bool operator!=(const Moustache<Dim>& lhs,
     134             :                           const Moustache<Dim>& rhs) {
     135             :   return not(lhs == rhs);
     136             : }
     137             : 
     138             : }  // namespace Poisson::Solutions