Struct HybridRepr 

pub struct HybridRepr {
    pub sheet: SheetTracker,
    pub grid: UniformGrid6D,
    pub domain: Domain,
    pub stream_threshold: u32,
    pub mask: Vec<bool>,
}

Hybrid representation combining SheetTracker and UniformGrid6D.

Single-stream regions (stream_count ≤ threshold) are tracked by the Lagrangian sheet (exact characteristics, zero diffusion). Multi-stream regions are handled by the Eulerian 6D grid (captures velocity dispersion).

The mask vector marks each spatial cell: true = grid mode, false = sheet mode.

Fields

sheet: SheetTracker

Lagrangian sheet tracker for single-stream regions.

grid: UniformGrid6D

Eulerian 6D grid for multi-stream regions.

domain: Domain

Simulation domain (spatial and velocity extents, boundary conditions).

stream_threshold: u32

Stream count above which a cell transitions from sheet to grid mode.

mask: Vec<bool>

Per spatial cell: true = grid mode (multi-stream), false = sheet mode.

Implementations

impl HybridRepr

pub fn new(domain: Domain) -> Self

Create a new hybrid representation with all cells initially in sheet mode.

pub fn update_interface(&mut self)

Transfer particles from SheetTracker to grid where stream_count > stream_threshold.

For each spatial cell where the stream count exceeds the threshold and is not yet in grid mode: deposit the sheet particles into the 6D grid via CIC and mark the cell as grid mode.

Trait Implementations

impl PhaseSpaceRepr for HybridRepr

fn compute_density(&self) -> DensityField

Compute density by selecting grid or sheet density per cell via the mask.

fn advect_x(&mut self, displacement: &DisplacementField, dt: f64)

Spatial drift: advance both sheet and grid, then update the interface mask.

fn advect_v(&mut self, acceleration: &AccelerationField, dt: f64)

Velocity kick: advance both sheet and grid, then update the interface mask.

fn moment(&self, position: &[f64; 3], order: usize) -> Tensor

Velocity moment dispatched to grid or sheet depending on the cell mask.

fn total_mass(&self) -> f64

Total mass summed over grid-mode and sheet-mode cells according to the mask.

fn casimir_c2(&self) -> f64

Casimir C2 invariant. Returns infinity if any cells are still in sheet mode (the sheet’s delta-function f makes C2 diverge).

fn entropy(&self) -> f64

Entropy. Sheet cells contribute zero; grid cells contribute normally.

fn stream_count(&self) -> StreamCountField

Stream count derived from the sheet tracker regardless of the cell mask.

fn velocity_distribution(&self, position: &[f64; 3]) -> Vec<f64>

Local velocity distribution dispatched to grid or sheet by cell mask.

fn total_kinetic_energy(&self) -> Option<f64>

Total kinetic energy. Uses the grid in all-grid mode, otherwise the sheet.

fn as_any(&self) -> &dyn Any

Downcast to &dyn Any for runtime type queries.

fn as_any_mut(&mut self) -> &mut dyn Any

Downcast to &mut dyn Any for runtime type queries.

fn to_snapshot(&self, time: f64) -> Option<PhaseSpaceSnapshot>

Extract a full 6D snapshot of the current state.

fn load_snapshot( &mut self, snap: PhaseSpaceSnapshot, ) -> Result<(), CausticError>

Replace the current state with data from a dense 6D snapshot.

fn can_materialize(&self) -> bool

Whether full 6D materialization fits in available memory. Default: true. Compressed representations (HT, TT) should override to check shape vs a memory threshold.

fn memory_bytes(&self) -> usize

Approximate memory usage of this representation in bytes. Default returns 0; implementations should override for accurate tracking.

fn set_progress(&mut self, _progress: Arc<StepProgress>)

Attach shared progress state for intra-phase cell-level reporting. Implementations can use this to report progress via StepProgress::set_intra_progress.