Global wave-speed / step-bound reductions and the HLL wave-speed cache. More...

#include <pops/core/state/state.hpp>
#include <pops/core/foundation/types.hpp>
#include <pops/mesh/storage/fab2d.hpp>
#include <pops/mesh/execution/for_each.hpp>
#include <pops/mesh/storage/multifab.hpp>
#include <pops/numerics/spatial/primitives/state_access.hpp>
#include <pops/parallel/comm.hpp>
#include <algorithm>
#include <limits>

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Classes
struct	pops::detail::MaxWaveSpeedKernel< Model >
	MaxWaveSpeedKernel<Model>: device reduction functor for max_wave_speed_mf. More...

struct	pops::detail::WaveSpeedMatchKernel< Model >
	Locates the cell DOMINATING the CFL (dt_hotspot diagnostic, ADC-182): EQUALITY scan of the recomputed w – same functor and same data as MaxWaveSpeedKernel, hence bit-equal to the max returned by max_wave_speed_mf – which encodes the GLOBAL index jnx + i as Real (exact as long as nxny < 2^53) and reduces to the MIN (first cell in lexicographic order: deterministic). More...

struct	pops::detail::StabilitySpeedKernel< Model >
	StabilitySpeedKernel: max over cells/directions of model.stability_speed (replaces MaxWaveSpeedKernel when the trait is declared). More...

struct	pops::detail::SourceFrequencyKernel< Model >
	SourceFrequencyKernel: max over cells of model.source_frequency (mu >= 0, 1/s). More...

struct	pops::detail::InvStabilityDtKernel< Model >
	InvStabilityDtKernel: max over cells of 1/model.stability_dt. More...

struct	pops::detail::WaveSpeedCacheKernel< Model >
	WaveSpeedCacheKernel: evaluates model.wave_speeds per cell in both directions and stores (lo_x, hi_x, lo_y, hi_y) in a 4-component scratch. More...

Namespaces
namespace	pops

namespace	pops::detail

Functions
template<class Model >
Real	pops::max_wave_speed_mf (const Model &model, const MultiFab &U, const MultiFab &aux)
	max_wave_speed_mf: global max of the wave speed over the whole MultiFab (CFL).

template<class Model >
void	pops::max_wave_speed_hotspot_mf (const Model &model, const MultiFab &U, const MultiFab &aux, int nx, Real &w_out, int &i_out, int &j_out)
	dt_hotspot diagnostic (ADC-182): the cell (GLOBAL indices) that dominates the block's transport CFL bound, and its speed w = max(wx, wy).

template<class Model >
Real	pops::max_stability_speed_mf (const Model &model, const MultiFab &U, const MultiFab &aux)
	Global max of the STABILITY speed (HasStabilitySpeed trait) – counterpart of max_wave_speed_mf.

template<class Model >
Real	pops::max_source_frequency_mf (const Model &model, const MultiFab &U, const MultiFab &aux)
	Global max of the source frequency (HasSourceFrequency trait). 0 if the source does not constrain.

template<class Model >
Real	pops::min_stability_dt_mf (const Model &model, const MultiFab &U, const MultiFab &aux)
	Global min of the declared admissible step (HasStabilityDt trait), via max(1/dt) (cf.

template<class Model >
void	pops::fill_wave_speed_cache (const Model &model, const MultiFab &U, const MultiFab &aux, MultiFab &cache)
	fill_wave_speed_cache: fills the per-cell wave speed scratch (lo_x, hi_x, lo_y, hi_y).

Detailed Description

Global wave-speed / step-bound reductions and the HLL wave-speed cache.

CONTRACT: the CFL and step-bound reductions over a whole MultiFab (device reduction + MPI all_reduce), plus the OPT-IN per-cell wave-speed scratch fill.

max_wave_speed_mf: global max CFL speed (collective under MPI).
max_wave_speed_hotspot_mf: cell dominating the CFL bound (diagnostic, ADC-182).
max_stability_speed_mf / max_source_frequency_mf / min_stability_dt_mf: optional step-bound traits (HasStabilitySpeed / HasSourceFrequency / HasStabilityDt).
fill_wave_speed_cache: per-cell (lo_x, hi_x, lo_y, hi_y) scratch for the HLL cache path (the scratch is CONSUMED in cartesian_operator.hpp).

COLLECTIVE UNDER MPI: every reduction aggregates via all_reduce over ALL ranks; without it each rank would choose a different dt and the simulation desynchronizes (see notes below).

include/pops/numerics/spatial/primitives/wave_speed.hpp File Reference¶

Classes

Namespaces

Functions

Detailed Description