Asymptotic-preserving IMEX (implicit-explicit) integrator: imex_euler_step, order-1 forward-backward Euler step, U^{n+1} = U^n + dt T(U^n) + dt S(U^{n+1}). More...

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

Include dependency graph for imex.hpp:

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Namespaces
namespace	pops

Functions
template<class TransportStep , class ImplicitSourceSolve >
void	pops::imex_euler_step (MultiFab &U, Real dt, TransportStep Texpl, ImplicitSourceSolve Simpl)

Detailed Description

Asymptotic-preserving IMEX (implicit-explicit) integrator: imex_euler_step, order-1 forward-backward Euler step, U^{n+1} = U^n + dt T(U^n) + dt S(U^{n+1}).

Layer: include/pops/numerics/time. Role: take the STIFF terms (Lorentz, Debye limit, quasi-neutrality) IMPLICITLY and the transport EXPLICITLY. AP property: when the small parameter (lambda_D^2, 1/omega_c) -> 0, the scheme stays stable at FIXED dt and captures the limit dynamics. Contract: Texpl(U, dt) advances the transport IN PLACE (after the call U holds the known term U^n + dt T(U^n)); Simpl(U, dt) solves IN PLACE U <- W with W = U + dt S(W), U being the known term (linear relaxation: analytic; full Lorentz: local Newton).

Invariants:

integrator agnostic of the model: Texpl/Simpl are callables (MultiFab&, Real)->void;
the order is enforced – explicit THEN implicit; no state held by the integrator.

include/pops/numerics/time/schemes/imex.hpp File Reference¶

Namespaces

Functions

Detailed Description