Time integrators as first-class OBJECTS with a take_step method: TimeStepper concept, and the ForwardEuler, SSPRK2Step, SSPRK3Step (Shu-Osher) schemes. More...

#include <pops/core/foundation/types.hpp>
#include <pops/mesh/storage/mf_arith.hpp>
#include <pops/mesh/storage/multifab.hpp>
#include <utility>

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Classes
struct	pops::ForwardEuler

struct	pops::ForwardEuler::Scratch

struct	pops::SSPRK2Step

struct	pops::SSPRK2Step::Scratch

struct	pops::SSPRK3Step

struct	pops::SSPRK3Step::Scratch

Namespaces
namespace	pops

Concepts
concept	pops::TimeStepper

Functions
template<class Stepper , class RhsEval >
void	pops::run_explicit_substeps (RhsEval &&rhs, MultiFab &U, Real h, int n)

Detailed Description

Time integrators as first-class OBJECTS with a take_step method: TimeStepper concept, and the ForwardEuler, SSPRK2Step, SSPRK3Step (Shu-Osher) schemes.

Layer: include/pops/numerics/time. Role: keep the mathematical scheme alive in the core, with the coupler CALLING it instead of inlining SSPRK everywhere. The "give a TimeIntegrator to the coupler like you give a PhysicalModel" contract: the user can provide their own (same signature take_step(rhs_eval, U, dt)). Contract: an integrator is agnostic of the model and the discretization – it only sees rhs_eval(U_stage, R) (the method-of-lines arrow R = -div F + S) and the MultiFab operations (saxpy / lincomb).

Invariants:

no carried state: the scratch (R, stages U1/U2/U3) is sized from the layout of U. The one-arg take_step allocates it per call; the scratch-taking overload reuses a caller-owned buffer (see run_explicit_substeps) to hoist the allocation out of a substep loop – both paths are bit-identical;
SSPRK2Step / SSPRK3Step exactly reproduce the old copies in SystemCoupler and ssprk.hpp (bit-identical).

include/pops/numerics/time/integrators/time_steppers.hpp File Reference¶

Classes

Namespaces

Concepts

Functions

Detailed Description