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 <cstdint>
       8              : #include <optional>
       9              : 
      10              : #include "DataStructures/TaggedVariant.hpp"
      11              : #include "Options/String.hpp"
      12              : #include "Time/StepperErrorEstimate.hpp"
      13              : #include "Time/StepperErrorTolerances.hpp"
      14              : #include "Time/TimeStepId.hpp"
      15              : #include "Time/TimeSteppers/TimeStepper.hpp"
      16              : #include "Utilities/Gsl.hpp"
      17              : #include "Utilities/Serialization/CharmPupable.hpp"
      18              : #include "Utilities/TMPL.hpp"
      19              : 
      20              : /// \cond
      21              : class TimeDelta;
      22              : namespace TimeSteppers {
      23              : template <typename T>
      24              : class ConstUntypedHistory;
      25              : template <typename T>
      26              : class MutableUntypedHistory;
      27              : }  // namespace TimeSteppers
      28              : /// \endcond
      29              : 
      30              : namespace TimeSteppers {
      31              : 
      32              : /// \ingroup TimeSteppersGroup
      33              : ///
      34              : /// A "strong stability-preserving" 3rd-order Runge-Kutta
      35              : /// time-stepper, as described in \cite HesthavenWarburton section
      36              : /// 5.7.
      37              : ///
      38              : /// The CFL factor/stable step size is 1.25637266330916.
      39              : ///
      40              : /// \note The time stepper is only strong-stability-preserving for
      41              : /// time steps not exceeding 1.0, i.e., slightly less than 0.8 times
      42              : /// the stable step.
      43            1 : class Rk3HesthavenSsp : public TimeStepper {
      44              :  public:
      45            0 :   using options = tmpl::list<>;
      46            0 :   static constexpr Options::String help = {
      47              :       "A third-order strong stability-preserving Runge-Kutta time-stepper."};
      48              : 
      49            0 :   Rk3HesthavenSsp() = default;
      50            0 :   Rk3HesthavenSsp(const Rk3HesthavenSsp&) = default;
      51            0 :   Rk3HesthavenSsp& operator=(const Rk3HesthavenSsp&) = default;
      52            0 :   Rk3HesthavenSsp(Rk3HesthavenSsp&&) = default;
      53            0 :   Rk3HesthavenSsp& operator=(Rk3HesthavenSsp&&) = default;
      54            0 :   ~Rk3HesthavenSsp() override = default;
      55              : 
      56            0 :   WRAPPED_PUPable_decl_template(Rk3HesthavenSsp);  // NOLINT
      57              : 
      58            0 :   explicit Rk3HesthavenSsp(CkMigrateMessage* /*unused*/) {}
      59              : 
      60            1 :   variants::TaggedVariant<Tags::FixedOrder, Tags::VariableOrder> order()
      61              :       const override;
      62              : 
      63            1 :   double stable_step() const override;
      64              : 
      65            1 :   bool monotonic() const override;
      66              : 
      67            1 :   bool dense_output_uses_fsal() const override;
      68              : 
      69            1 :   uint64_t number_of_substeps() const override;
      70              : 
      71            1 :   uint64_t number_of_substeps_for_error() const override;
      72              : 
      73            1 :   size_t number_of_past_steps() const override;
      74              : 
      75            1 :   TimeStepId next_time_id(const TimeStepId& current_id,
      76              :                           const TimeDelta& time_step) const override;
      77              : 
      78            1 :   TimeStepId next_time_id_for_error(const TimeStepId& current_id,
      79              :                                     const TimeDelta& time_step) const override;
      80              : 
      81              :  private:
      82              :   template <typename T>
      83            0 :   std::optional<StepperErrorEstimate> update_u_impl(
      84              :       gsl::not_null<T*> u, const ConstUntypedHistory<T>& history,
      85              :       const TimeDelta& time_step,
      86              :       const StepperErrorTolerances& tolerances = {}) const;
      87              : 
      88              :   template <typename T>
      89            0 :   void clean_history_impl(const MutableUntypedHistory<T>& history) const;
      90              : 
      91              :   template <typename T>
      92            0 :   bool dense_update_u_impl(gsl::not_null<T*> u,
      93              :                            const ConstUntypedHistory<T>& history,
      94              :                            double time) const;
      95              : 
      96              :   template <typename T>
      97            0 :   bool can_change_step_size_impl(const TimeStepId& time_id,
      98              :                                  const ConstUntypedHistory<T>& history) const;
      99              : 
     100              :   TIME_STEPPER_DECLARE_OVERLOADS
     101              : };
     102              : 
     103            0 : inline bool constexpr operator==(const Rk3HesthavenSsp& /*lhs*/,
     104              :                                  const Rk3HesthavenSsp& /*rhs*/) {
     105              :   return true;
     106              : }
     107              : 
     108            0 : inline bool constexpr operator!=(const Rk3HesthavenSsp& /*lhs*/,
     109              :                                  const Rk3HesthavenSsp& /*rhs*/) {
     110              :   return false;
     111              : }
     112              : }  // namespace TimeSteppers