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 "Options/String.hpp"
      11             : #include "Time/StepperErrorEstimate.hpp"
      12             : #include "Time/TimeStepId.hpp"
      13             : #include "Time/TimeSteppers/TimeStepper.hpp"
      14             : #include "Utilities/Gsl.hpp"
      15             : #include "Utilities/Serialization/CharmPupable.hpp"
      16             : #include "Utilities/TMPL.hpp"
      17             : 
      18             : /// \cond
      19             : struct StepperErrorTolerances;
      20             : class TimeDelta;
      21             : namespace TimeSteppers {
      22             : template <typename T>
      23             : class ConstUntypedHistory;
      24             : template <typename T>
      25             : class MutableUntypedHistory;
      26             : }  // namespace TimeSteppers
      27             : /// \endcond
      28             : 
      29             : namespace TimeSteppers {
      30             : 
      31             : /// \ingroup TimeSteppersGroup
      32             : ///
      33             : /// A "strong stability-preserving" 3rd-order Runge-Kutta
      34             : /// time-stepper, as described in \cite HesthavenWarburton section
      35             : /// 5.7.
      36             : ///
      37             : /// The CFL factor/stable step size is 1.25637266330916.
      38             : ///
      39             : /// \note The time stepper is only strong-stability-preserving for
      40             : /// time steps not exceeding 1.0, i.e., slightly less than 0.8 times
      41             : /// the stable step.
      42           1 : class Rk3HesthavenSsp : public TimeStepper {
      43             :  public:
      44           0 :   using options = tmpl::list<>;
      45           0 :   static constexpr Options::String help = {
      46             :       "A third-order strong stability-preserving Runge-Kutta time-stepper."};
      47             : 
      48           0 :   Rk3HesthavenSsp() = default;
      49           0 :   Rk3HesthavenSsp(const Rk3HesthavenSsp&) = default;
      50           0 :   Rk3HesthavenSsp& operator=(const Rk3HesthavenSsp&) = default;
      51           0 :   Rk3HesthavenSsp(Rk3HesthavenSsp&&) = default;
      52           0 :   Rk3HesthavenSsp& operator=(Rk3HesthavenSsp&&) = default;
      53           0 :   ~Rk3HesthavenSsp() override = default;
      54             : 
      55           0 :   WRAPPED_PUPable_decl_template(Rk3HesthavenSsp);  // NOLINT
      56             : 
      57           0 :   explicit Rk3HesthavenSsp(CkMigrateMessage* /*unused*/) {}
      58             : 
      59           1 :   size_t order() const override;
      60             : 
      61           1 :   double stable_step() const override;
      62             : 
      63           1 :   bool monotonic() const override;
      64             : 
      65           1 :   uint64_t number_of_substeps() const override;
      66             : 
      67           1 :   uint64_t number_of_substeps_for_error() const override;
      68             : 
      69           1 :   size_t number_of_past_steps() const override;
      70             : 
      71           1 :   TimeStepId next_time_id(const TimeStepId& current_id,
      72             :                           const TimeDelta& time_step) const override;
      73             : 
      74           1 :   TimeStepId next_time_id_for_error(const TimeStepId& current_id,
      75             :                                     const TimeDelta& time_step) const override;
      76             : 
      77             :  private:
      78             :   template <typename T>
      79           0 :   void update_u_impl(gsl::not_null<T*> u, const ConstUntypedHistory<T>& history,
      80             :                      const TimeDelta& time_step) const;
      81             : 
      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 std::optional<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