Advection Parameters

AdvectionParameters control the level-set advection step (i.e., how the geometry is advanced in time based on the model-provided velocity field). These parameters mainly affect stability, accuracy, and runtime.

integrationScheme is a legacy name for spatialScheme and is deprecated.

Field	Type	Default	Description
`spatialScheme`	`SpatialScheme`	`ENGQUIST_OSHER_1ST_ORDER`	Spatial discretization scheme for the level-set advection.
`integrationScheme` (deprecated)	`SpatialScheme`	`ENGQUIST_OSHER_1ST_ORDER`	Legacy alias for `spatialScheme`. Use `spatialScheme` instead.
`temporalScheme`	`TemporalScheme`	`FORWARD_EULER`	Time integration scheme for advection.
`timeStepRatio`	`double`	`0.4999`	CFL ratio used to compute the time step from the maximum stable step. Values closer to `0.5` are larger/faster but less conservative.
`dissipationAlpha`	`double`	`1.0`	Lax–Friedrichs dissipation scaling. Higher values are more diffusive (more stable, less sharp).
`adaptiveTimeStepSubdivisions`	`unsigned`	`20`	Subdivisions used when adaptive time stepping is enabled. Higher values can improve robustness near interfaces at increased cost.
`checkDissipation`	`bool`	`true`	Enable dissipation checks (helps avoid unstable time steps).
`velocityOutput`	`bool`	`false`	Write velocity output per step (useful for debugging/analysis; may increase I/O).
`ignoreVoids`	`bool`	`false`	Ignore void regions during advection (model-dependent usefulness).
`adaptiveTimeStepping`	`bool`	`false`	Enable adaptive time stepping when approaching material interfaces (primarily relevant for etching).

Enum values

SpatialScheme corresponds to viennals::SpatialSchemeEnum (common options include ENGQUIST_OSHER_1ST_ORDER, ENGQUIST_OSHER_2ND_ORDER, LAX_FRIEDRICHS_1ST_ORDER, LAX_FRIEDRICHS_2ND_ORDER, WENO_5TH_ORDER).

TemporalScheme corresponds to viennals::TemporalSchemeEnum (FORWARD_EULER, RUNGE_KUTTA_2ND_ORDER, RUNGE_KUTTA_3RD_ORDER).