celeritas::GeantGeoTrackView Class Reference

Navigate through a Geant4 geometry on a single thread. More...

#include <GeantGeoTrackView.hh>

Public Member Functions
	GeantGeoTrackView (ParamsRef const &params, StateRef const &state, TrackSlotId tid)
	Construct from params and state data.
GeantGeoTrackView &	operator= (Initializer_t const &init)
	Construct the state.
VolumeId	volume_id () const
	Get the canonical volume ID in the current implementation volume.
VolumeInstanceId	volume_instance_id () const
	Get the physical volume ID in the current cell.
VolumeLevelId	volume_level () const
	Get the depth in the geometry hierarchy.
void	volume_instance_id (Span< VolumeInstanceId > levels) const
	Get the volume instance ID at every level.
ImplVolumeId	impl_volume_id () const
	Get the volume ID in the current cell.
GeoStatus	geo_status () const
	Geometry tracking status.
bool	is_outside () const
	Whether the track is outside the valid geometry region.
bool	is_on_boundary () const
	Whether the track is on the boundary of a volume.
bool	failed () const
	Whether the last operation resulted in an error.
Real3 const &	normal () const
	Get the exit surface normal of the boundary the track has just crossed.
Propagation	find_next_step (real_type max_step)
	Find the distance to the next geometric boundary.
real_type	find_safety ()
	Find the safety at the current position.
real_type	find_safety (real_type max_step)
	Find the safety at the current position.
void	move_to_boundary ()
	Move to the next boundary but don't cross yet.
void	move_internal (real_type step)
	Move within the current volume.
void	move_internal (Real3 const &pos)
	Move within the current volume to a nearby point.
void	cross_boundary ()
	Cross from one side of the current surface to the other.
void	set_dir (Real3 const &newdir)
	Change the track's direction.
G4NavigationHistory const *	nav_history () const
	Get the navigation state.

Type aliases
using	Initializer_t = GeoTrackInitializer
using	ParamsRef = NativeCRef< GeantGeoParamsData >
using	StateRef = NativeRef< GeantGeoStateData >
using	real_type = double
using	Real3 = Array< real_type, 3 >
Real3 const &	pos () const
Real3 const &	dir () const

Detailed Description

Navigate through a Geant4 geometry on a single thread.

This wraps a Geant4 geometry navigator and volume hierarchy state with the same Celeritas tracker interface. It's not going to be the most efficient code since the G4Navigator includes a lot of helper functions for managing safety distance, tracking through a field, etc. We also independently store a "celeritas" native position and direction, as well as duplicating the "geant4" position and direction that are also stored under the hood in the heavyweight navigator.

Geant4 thinks about boundaries differently to Celeritas. When we find the next step, it will internally store the "blocking" volume (daughter="entering", current volume="exiting") and the normal at that point. The G4 navigation in practice has three options:

1. move within the safety distance, which is calculated as a side effect of ComputeStep
2. move to the end-of-step position, call SetGeometricallyLimitedStep, and update the volume via LocateGlobalPointAndUpdateTouchableHandle
3. move to a position outside the safety and update with LocateGlobalPointWithinVolume .

See also

GeoTrackInterface

Member Typedef Documentation

Initializer_t

using celeritas::GeantGeoTrackView::Initializer_t = GeoTrackInitializer

State accessors

ParamsRef

using celeritas::GeantGeoTrackView::ParamsRef = NativeCRef<GeantGeoParamsData>

State accessors

Real3

using celeritas::GeantGeoTrackView::Real3 = Array<real_type, 3>

State accessors

real_type

using celeritas::GeantGeoTrackView::real_type = double

State accessors

StateRef

using celeritas::GeantGeoTrackView::StateRef = NativeRef<GeantGeoStateData>

State accessors

Member Function Documentation

cross_boundary()

void celeritas::GeantGeoTrackView::cross_boundary ( )

inline

Cross from one side of the current surface to the other.

The position must be on the boundary following a move-to-boundary.

dir()

Real3 const & celeritas::GeantGeoTrackView::dir ( ) const

inline

State accessors

find_safety()

auto celeritas::GeantGeoTrackView::find_safety ( real_type  max_step )

inline

Find the safety at the current position.

Warning

This can change the boundary state if the track was moved to or initialized a point on the boundary.

move_internal() [1/2]

void celeritas::GeantGeoTrackView::move_internal ( Real3 const &  pos )

inline

Move within the current volume to a nearby point.

See G4PathFinder::ReLocate from G4SafetyHelper::ReLocateWithinVolume from G4VMultipleScattering::AlongStepDoIt .

move_internal() [2/2]

void celeritas::GeantGeoTrackView::move_internal ( real_type  dist )

inline

Move within the current volume.

The straight-line distance must be less than the distance to the boundary.

normal()

auto celeritas::GeantGeoTrackView::normal ( ) const

inline

Get the exit surface normal of the boundary the track has just crossed.

This vector is in the global coordinate system.

pos()

Real3 const & celeritas::GeantGeoTrackView::pos ( ) const

inline

State accessors

set_dir()

void celeritas::GeantGeoTrackView::set_dir ( Real3 const &  newdir )

inline

Change the track's direction.

This happens after a scattering event or movement inside a magnetic field. It resets the calculated distance-to-boundary.

volume_id()

VolumeId celeritas::GeantGeoTrackView::volume_id ( ) const

inline

Get the canonical volume ID in the current implementation volume.

Note

See GeantGeoParams::volume_id : for now, identical to ImplVolumeId

volume_instance_id()

void celeritas::GeantGeoTrackView::volume_instance_id ( Span< VolumeInstanceId >  levels ) const

inline

Get the volume instance ID at every level.

The input span size must be equal to the value of "volume_level" plus one. The top-most level ("world" or level zero) starts at index zero and moves downward. Note that Geant4 uses the reverse nomenclature.

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The documentation for this class was generated from the following file:

• GeantGeoTrackView.hh