SpECTRE Documentation Coverage Report
 Current view: top level - Time/TimeSteppers - Rk4Owren.hpp Hit Total Coverage Commit: 9f349d3c09e1c03107f00c2135ca40e209d3b84c Lines: 4 18 22.2 % Date: 2023-06-09 21:05:06 Legend: Lines: hit not hit
  Line data Source code  1 0 : // Distributed under the MIT License. 2 : // See LICENSE.txt for details. 3 : 4 : #pragma once 5 : 6 : #include 7 : 8 : #include "Options/String.hpp" 9 : #include "Time/TimeSteppers/RungeKutta.hpp" 10 : #include "Utilities/Serialization/CharmPupable.hpp" 11 : #include "Utilities/TMPL.hpp" 12 : 13 : namespace TimeSteppers { 14 : /*! 15 : * \ingroup TimeSteppersGroup 16 : * \brief A fourth order continuous-extension RK method that provides 4th-order 17 : * dense output. 18 : * 19 : * \f{eqnarray}{ 20 : * \frac{du}{dt} & = & \mathcal{L}(t,u). 21 : * \f} 22 : * Given a solution \f$u(t^n)=u^n\f$, this stepper computes 23 : * \f$u(t^{n+1})=u^{n+1}\f$ using the following equations: 24 : * 25 : * \f{align}{ 26 : * k^{(i)} & = \mathcal{L}(t^n + c_i \Delta t, 27 : * u^n + \Delta t \sum_{j=1}^{i-1} a_{ij} k^{(j)}), 28 : * \mbox{ } 1 \leq i \leq s,\\ 29 : * u^{n+1}(t^n + \theta \Delta t) & = u^n + \Delta t \sum_{i=1}^{s} b_i(\theta) 30 : * k^{(i)}. \f} 31 : * 32 : * Here the coefficients \f$a_{ij}\f$, \f$b_i\f$, and \f$c_i\f$ are given 33 : * in \cite Owren1992 and \cite Gassner20114232. Note that \f$c_1 = 0\f$, 34 : * \f$s\f$ is the number of stages, and \f$\theta\f$ is the fraction of the 35 : * step. This is an FSAL stepper. 36 : * 37 : * The CFL factor/stable step size is 1.4367588951002057. 38 : */ 39 1 : class Rk4Owren : public RungeKutta { 40 : public: 41 0 : using options = tmpl::list<>; 42 0 : static constexpr Options::String help = { 43 : "A 4th-order continuous extension Runge-Kutta time stepper."}; 44 : 45 0 : Rk4Owren() = default; 46 0 : Rk4Owren(const Rk4Owren&) = default; 47 0 : Rk4Owren& operator=(const Rk4Owren&) = default; 48 0 : Rk4Owren(Rk4Owren&&) = default; 49 0 : Rk4Owren& operator=(Rk4Owren&&) = default; 50 0 : ~Rk4Owren() override = default; 51 : 52 1 : size_t order() const override; 53 : 54 1 : size_t error_estimate_order() const override; 55 : 56 1 : double stable_step() const override; 57 : 58 0 : WRAPPED_PUPable_decl_template(Rk4Owren); // NOLINT 59 : 60 0 : explicit Rk4Owren(CkMigrateMessage* /*msg*/); 61 : 62 0 : const ButcherTableau& butcher_tableau() const override; 63 : }; 64 : 65 0 : inline bool constexpr operator==(const Rk4Owren& /*lhs*/, 66 : const Rk4Owren& /*rhs*/) { 67 : return true; 68 : } 69 : 70 0 : inline bool constexpr operator!=(const Rk4Owren& /*lhs*/, 71 : const Rk4Owren& /*rhs*/) { 72 : return false; 73 : } 74 : } // namespace TimeSteppers 

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