SpECTRE Documentation Coverage Report
Current view: top level - Time/TimeSteppers - TimeStepper.hpp Hit Total Coverage
Commit: e1f22ede76131d2a431eabbd2dd32008f3162edb Lines: 17 22 77.3 %
Date: 2025-04-16 15:32:12
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          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             : #include <pup.h>
      10             : #include <type_traits>
      11             : 
      12             : #include "DataStructures/MathWrapper.hpp"
      13             : #include "Time/History.hpp"
      14             : #include "Time/StepperErrorEstimate.hpp"
      15             : #include "Utilities/GenerateInstantiations.hpp"
      16             : #include "Utilities/Gsl.hpp"
      17             : #include "Utilities/Serialization/CharmPupable.hpp"
      18             : 
      19             : /// \cond
      20             : struct StepperErrorTolerances;
      21             : class TimeDelta;
      22             : class TimeStepId;
      23             : /// \endcond
      24             : 
      25             : /// \ingroup TimeSteppersGroup
      26             : ///
      27             : /// Holds classes that take time steps.
      28             : namespace TimeSteppers {}
      29             : 
      30             : /// \cond
      31             : #define TIME_STEPPER_WRAPPED_TYPE(data) BOOST_PP_TUPLE_ELEM(0, data)
      32             : #define TIME_STEPPER_DERIVED_CLASS(data) BOOST_PP_TUPLE_ELEM(1, data)
      33             : #define TIME_STEPPER_DERIVED_CLASS_TEMPLATE(data) BOOST_PP_TUPLE_ELEM(2, data)
      34             : /// \endcond
      35             : 
      36             : /// \ingroup TimeSteppersGroup
      37             : ///
      38             : /// Abstract base class for TimeSteppers.
      39             : ///
      40             : /// Several of the member functions of this class are templated and
      41             : /// perform type erasure before forwarding their arguments to the
      42             : /// derived classes.  This is implemented using the macros \ref
      43             : /// TIME_STEPPER_DECLARE_OVERLOADS, which must be placed in a private
      44             : /// section of the class body, and
      45             : /// TIME_STEPPER_DEFINE_OVERLOADS(derived_class), which must be placed
      46             : /// in the cpp file.
      47           1 : class TimeStepper : public PUP::able {
      48             :  public:
      49           0 :   static constexpr bool local_time_stepping = false;
      50           0 :   static constexpr bool imex = false;
      51           0 :   using provided_time_stepper_interfaces = tmpl::list<TimeStepper>;
      52             : 
      53           0 :   WRAPPED_PUPable_abstract(TimeStepper);  // NOLINT
      54             : 
      55             :   /// \cond
      56             : #define TIME_STEPPER_DECLARE_VIRTUALS_IMPL(_, data)                        \
      57             :   virtual void update_u_forward(                                           \
      58             :       const gsl::not_null<TIME_STEPPER_WRAPPED_TYPE(data)*> u,             \
      59             :       const TimeSteppers::ConstUntypedHistory<TIME_STEPPER_WRAPPED_TYPE(   \
      60             :           data)>& history,                                                 \
      61             :       const TimeDelta& time_step) const = 0;                               \
      62             :   virtual std::optional<StepperErrorEstimate> update_u_forward(            \
      63             :       const gsl::not_null<TIME_STEPPER_WRAPPED_TYPE(data)*> u,             \
      64             :       const TimeSteppers::ConstUntypedHistory<TIME_STEPPER_WRAPPED_TYPE(   \
      65             :           data)>& history,                                                 \
      66             :       const TimeDelta& time_step,                                          \
      67             :       const std::optional<StepperErrorTolerances>& tolerances) const = 0;  \
      68             :   virtual void clean_history_forward(                                      \
      69             :       const TimeSteppers::MutableUntypedHistory<TIME_STEPPER_WRAPPED_TYPE( \
      70             :           data)>& history) const = 0;                                      \
      71             :   virtual bool dense_update_u_forward(                                     \
      72             :       const gsl::not_null<TIME_STEPPER_WRAPPED_TYPE(data)*> u,             \
      73             :       const TimeSteppers::ConstUntypedHistory<TIME_STEPPER_WRAPPED_TYPE(   \
      74             :           data)>& history,                                                 \
      75             :       double time) const = 0;                                              \
      76             :   virtual bool can_change_step_size_forward(                               \
      77             :       const TimeStepId& time_id,                                           \
      78             :       const TimeSteppers::ConstUntypedHistory<TIME_STEPPER_WRAPPED_TYPE(   \
      79             :           data)>& history) const = 0;
      80             : 
      81             :   GENERATE_INSTANTIATIONS(TIME_STEPPER_DECLARE_VIRTUALS_IMPL,
      82             :                           (MATH_WRAPPER_TYPES))
      83             : #undef TIME_STEPPER_DECLARE_VIRTUALS_IMPL
      84             :   /// \endcond
      85             : 
      86             :   /// Set \p u to the value at the end of the current substep.
      87             :   ///
      88             :   /// Derived classes must implement this as a function with signature
      89             :   ///
      90             :   /// ```
      91             :   /// template <typename T>
      92             :   /// void update_u_impl(gsl::not_null<T*> u,
      93             :   ///                    const ConstUntypedHistory<T>& history,
      94             :   ///                    const TimeDelta& time_step) const;
      95             :   /// ```
      96             :   template <typename Vars>
      97           1 :   void update_u(const gsl::not_null<Vars*> u,
      98             :                 const TimeSteppers::History<Vars>& history,
      99             :                 const TimeDelta& time_step) const {
     100             :     return update_u_forward(&*make_math_wrapper(u), history.untyped(),
     101             :                             time_step);
     102             :   }
     103             : 
     104             :   /// Set \p u to the value at the end of the current substep; report the error
     105             :   /// measure when available.
     106             :   ///
     107             :   /// For a substep method, the error measure will only be available on full
     108             :   /// steps. For a multistep method, the error measure will only be available
     109             :   /// when a sufficient number of steps are available in the `history` to
     110             :   /// compare two orders of step. Whenever the error measure is unavailable,
     111             :   /// the return value is empty
     112             :   ///
     113             :   /// If \p tolerances is empty, no error measures are calculated, but
     114             :   /// any additional substeps necessary for error estimation are still
     115             :   /// taken.  This is useful when a system integrates multiple
     116             :   /// variables in separate calls to the TimeStepper, but only uses
     117             :   /// estimates from some of them.
     118             :   ///
     119             :   /// Derived classes must implement this as a function with signature
     120             :   ///
     121             :   /// ```
     122             :   /// template <typename T>
     123             :   /// std::optional<StepperErrorEstimate> update_u_impl(
     124             :   ///     gsl::not_null<T*> u,
     125             :   ///     const ConstUntypedHistory<T>& history,
     126             :   ///     const TimeDelta& time_step,
     127             :   ///     const std::optional<StepperErrorTolerances>& tolerances) const;
     128             :   /// ```
     129             :   template <typename Vars>
     130           1 :   std::optional<StepperErrorEstimate> update_u(
     131             :       const gsl::not_null<Vars*> u, const TimeSteppers::History<Vars>& history,
     132             :       const TimeDelta& time_step,
     133             :       const std::optional<StepperErrorTolerances>& tolerances) const {
     134             :     return update_u_forward(&*make_math_wrapper(u), history.untyped(),
     135             :                             time_step, tolerances);
     136             :   }
     137             : 
     138             :   /// Remove old entries from the history.
     139             :   ///
     140             :   /// This should be called after update_u and dense output.
     141             :   /// Afterward, the history will generally require a new entry to be
     142             :   /// added before it can be used by the TimeStepper.
     143             :   ///
     144             :   /// Derived classes must implement this as a function with signature
     145             :   ///
     146             :   /// ```
     147             :   /// template <typename T>
     148             :   /// void clean_history_impl(const MutableUntypedHistory<T>& history) const;
     149             :   /// ```
     150             :   template <typename Vars>
     151           1 :   void clean_history(
     152             :       const gsl::not_null<TimeSteppers::History<Vars>*> history) const {
     153             :     return clean_history_forward(history->untyped());
     154             :   }
     155             : 
     156             :   /// Compute the solution value at a time between steps.  To evaluate
     157             :   /// at a time within a given step, call this method at the start of
     158             :   /// the step containing the time.  The function returns true on
     159             :   /// success, otherwise the call should be retried after the next
     160             :   /// substep.
     161             :   ///
     162             :   /// The change from the partial step will be added to the initial
     163             :   /// value, so \p u should generally be initialized to
     164             :   /// `*history.step_start(time).value`.  (TimeStepper
     165             :   /// implementations are required to keep this value in the history.)
     166             :   ///
     167             :   /// Derived classes must implement this as a function with signature
     168             :   ///
     169             :   /// ```
     170             :   /// template <typename T>
     171             :   /// bool dense_update_u_impl(
     172             :   ///     gsl::not_null<T*> u, const ConstUntypedHistory<T>& history,
     173             :   ///     double time) const;
     174             :   /// ```
     175             :   template <typename Vars>
     176           1 :   bool dense_update_u(const gsl::not_null<Vars*> u,
     177             :                       const TimeSteppers::History<Vars>& history,
     178             :                       const double time) const {
     179             :     return dense_update_u_forward(&*make_math_wrapper(u), history.untyped(),
     180             :                                   time);
     181             :   }
     182             : 
     183             :   /// The convergence order of the stepper
     184           1 :   virtual size_t order() const = 0;
     185             : 
     186             :   /// Number of substeps in this TimeStepper
     187           1 :   virtual uint64_t number_of_substeps() const = 0;
     188             : 
     189             :   /// Number of substeps in this TimeStepper when providing an error measure for
     190             :   /// adaptive time-stepping
     191             :   ///
     192             :   /// \details Certain substep methods (e.g. embedded RK4(3)) require additional
     193             :   /// steps when providing an error measure of the integration.
     194           1 :   virtual uint64_t number_of_substeps_for_error() const = 0;
     195             : 
     196             :   /// Number of past time steps needed for multi-step method
     197           1 :   virtual size_t number_of_past_steps() const = 0;
     198             : 
     199             :   /// Rough estimate of the maximum step size this method can take
     200             :   /// stably as a multiple of the step for Euler's method.
     201           1 :   virtual double stable_step() const = 0;
     202             : 
     203             :   /// Whether computational and temporal orderings of operations
     204             :   /// match.
     205             :   ///
     206             :   /// If this method returns true, then, for two time-stepper
     207             :   /// operations occurring at different simulation times, the
     208             :   /// temporally earlier operation will be performed first.  These
     209             :   /// operations include RHS evaluation, dense output, and neighbor
     210             :   /// communication.  In particular, dense output never requires
     211             :   /// performing a RHS evaluation later than the output time, so
     212             :   /// control systems measurements cannot cause deadlocks.
     213             :   ///
     214             :   /// \warning This guarantee only holds if the time steps themselves
     215             :   /// are monotonic, which can be violated during initialization.
     216           1 :   virtual bool monotonic() const = 0;
     217             : 
     218             :   /// The TimeStepId after the current substep
     219           1 :   virtual TimeStepId next_time_id(const TimeStepId& current_id,
     220             :                                   const TimeDelta& time_step) const = 0;
     221             : 
     222             :   /// The TimeStepId after the current substep when providing an error measure
     223             :   /// for adaptive time-stepping.
     224             :   ///
     225             :   /// Certain substep methods (e.g. embedded RK4(3)) require additional
     226             :   /// steps when providing an error measure of the integration.
     227           1 :   virtual TimeStepId next_time_id_for_error(
     228             :       const TimeStepId& current_id, const TimeDelta& time_step) const = 0;
     229             : 
     230             :   /// Whether a change in the step size is allowed before taking
     231             :   /// a step.  Step sizes can never be changed on a substep.
     232             :   ///
     233             :   /// Derived classes must implement this as a function with signature
     234             :   ///
     235             :   /// ```
     236             :   /// template <typename T>
     237             :   /// bool can_change_step_size_impl(
     238             :   ///     const TimeStepId& time_id,
     239             :   ///     const ConstUntypedHistory<T>& history) const;
     240             :   /// ```
     241             :   template <typename Vars>
     242           1 :   bool can_change_step_size(const TimeStepId& time_id,
     243             :                             const TimeSteppers::History<Vars>& history) const {
     244             :     return can_change_step_size_forward(time_id, history.untyped());
     245             :   }
     246             : };
     247             : 
     248             : /// \cond
     249             : #define TIME_STEPPER_DECLARE_OVERLOADS_IMPL(_, data)                           \
     250             :   void update_u_forward(                                                       \
     251             :       gsl::not_null<TIME_STEPPER_WRAPPED_TYPE(data)*> u,                       \
     252             :       const TimeSteppers::ConstUntypedHistory<TIME_STEPPER_WRAPPED_TYPE(       \
     253             :           data)>& history,                                                     \
     254             :       const TimeDelta& time_step) const override;                              \
     255             :   std::optional<StepperErrorEstimate> update_u_forward(                        \
     256             :       gsl::not_null<TIME_STEPPER_WRAPPED_TYPE(data)*> u,                       \
     257             :       const TimeSteppers::ConstUntypedHistory<TIME_STEPPER_WRAPPED_TYPE(       \
     258             :           data)>& history,                                                     \
     259             :       const TimeDelta& time_step,                                              \
     260             :       const std::optional<StepperErrorTolerances>& tolerances) const override; \
     261             :   void clean_history_forward(                                                  \
     262             :       const TimeSteppers::MutableUntypedHistory<TIME_STEPPER_WRAPPED_TYPE(     \
     263             :           data)>& history) const override;                                     \
     264             :   bool dense_update_u_forward(                                                 \
     265             :       gsl::not_null<TIME_STEPPER_WRAPPED_TYPE(data)*> u,                       \
     266             :       const TimeSteppers::ConstUntypedHistory<TIME_STEPPER_WRAPPED_TYPE(       \
     267             :           data)>& history,                                                     \
     268             :       double time) const override;                                             \
     269             :   bool can_change_step_size_forward(                                           \
     270             :       const TimeStepId& time_id,                                               \
     271             :       const TimeSteppers::ConstUntypedHistory<TIME_STEPPER_WRAPPED_TYPE(       \
     272             :           data)>& history) const override;
     273             : 
     274             : #define TIME_STEPPER_DEFINE_OVERLOADS_IMPL(_, data)                        \
     275             :   TIME_STEPPER_DERIVED_CLASS_TEMPLATE(data)                                \
     276             :   void TIME_STEPPER_DERIVED_CLASS(data)::update_u_forward(                 \
     277             :       const gsl::not_null<TIME_STEPPER_WRAPPED_TYPE(data)*> u,             \
     278             :       const TimeSteppers::ConstUntypedHistory<TIME_STEPPER_WRAPPED_TYPE(   \
     279             :           data)>& history,                                                 \
     280             :       const TimeDelta& time_step) const {                                  \
     281             :     return update_u_impl(u, history, time_step);                           \
     282             :   }                                                                        \
     283             :   TIME_STEPPER_DERIVED_CLASS_TEMPLATE(data)                                \
     284             :   std::optional<StepperErrorEstimate>                                      \
     285             :   TIME_STEPPER_DERIVED_CLASS(data)::update_u_forward(                      \
     286             :       const gsl::not_null<TIME_STEPPER_WRAPPED_TYPE(data)*> u,             \
     287             :       const TimeSteppers::ConstUntypedHistory<TIME_STEPPER_WRAPPED_TYPE(   \
     288             :           data)>& history,                                                 \
     289             :       const TimeDelta& time_step,                                          \
     290             :       const std::optional<StepperErrorTolerances>& tolerances) const {     \
     291             :     return update_u_impl(u, history, time_step, tolerances);               \
     292             :   }                                                                        \
     293             :   TIME_STEPPER_DERIVED_CLASS_TEMPLATE(data)                                \
     294             :   void TIME_STEPPER_DERIVED_CLASS(data)::clean_history_forward(            \
     295             :       const TimeSteppers::MutableUntypedHistory<TIME_STEPPER_WRAPPED_TYPE( \
     296             :           data)>& history) const {                                         \
     297             :     return clean_history_impl(history);                                    \
     298             :   }                                                                        \
     299             :   TIME_STEPPER_DERIVED_CLASS_TEMPLATE(data)                                \
     300             :   bool TIME_STEPPER_DERIVED_CLASS(data)::dense_update_u_forward(           \
     301             :       const gsl::not_null<TIME_STEPPER_WRAPPED_TYPE(data)*> u,             \
     302             :       const TimeSteppers::ConstUntypedHistory<TIME_STEPPER_WRAPPED_TYPE(   \
     303             :           data)>& history,                                                 \
     304             :       const double time) const {                                           \
     305             :     return dense_update_u_impl(u, history, time);                          \
     306             :   }                                                                        \
     307             :   TIME_STEPPER_DERIVED_CLASS_TEMPLATE(data)                                \
     308             :   bool TIME_STEPPER_DERIVED_CLASS(data)::can_change_step_size_forward(     \
     309             :       const TimeStepId& time_id,                                           \
     310             :       const TimeSteppers::ConstUntypedHistory<TIME_STEPPER_WRAPPED_TYPE(   \
     311             :           data)>& history) const {                                         \
     312             :     return can_change_step_size_impl(time_id, history);                    \
     313             :   }
     314             : /// \endcond
     315             : 
     316             : /// \ingroup TimeSteppersGroup
     317             : /// Macro declaring overloaded detail methods in classes derived from
     318             : /// TimeStepper.  Must be placed in a private section of the class
     319             : /// body.
     320           1 : #define TIME_STEPPER_DECLARE_OVERLOADS                         \
     321             :   GENERATE_INSTANTIATIONS(TIME_STEPPER_DECLARE_OVERLOADS_IMPL, \
     322             :                           (MATH_WRAPPER_TYPES))
     323             : 
     324             : /// \ingroup TimeSteppersGroup
     325             : /// Macro defining overloaded detail methods in classes derived from
     326             : /// TimeStepper.  Must be placed in the cpp file for the derived
     327             : /// class.
     328             : /// @{
     329           1 : #define TIME_STEPPER_DEFINE_OVERLOADS(derived_class)          \
     330             :   GENERATE_INSTANTIATIONS(TIME_STEPPER_DEFINE_OVERLOADS_IMPL, \
     331             :                           (MATH_WRAPPER_TYPES), (derived_class), ())
     332           1 : #define TIME_STEPPER_DEFINE_OVERLOADS_TEMPLATED(derived_class, template_args) \
     333             :   GENERATE_INSTANTIATIONS(TIME_STEPPER_DEFINE_OVERLOADS_IMPL,                 \
     334             :                           (MATH_WRAPPER_TYPES), (derived_class),              \
     335             :                           (template <template_args>))
     336             : /// @}

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