o2::acts Namespace Reference

Classes
class	ActsGeometryService
class	ITrackingGeometryBuilder
class	MagneticFieldAdapter
class	SurfaceIndexMap
class	TrackingGeometryManager
struct	TrackingGeometryOutput

Typedefs
using	SensorPathProvider = std::function< std::string(int sensorID)>
	Full TGeo node path of one sensor, e.g. o2::trk::GeometryTGeo::getMatrixPath().

Functions
SurfaceIndexMap	makeSurfaceIndex (const Acts::TrackingGeometry &geometry, const Acts::GeometryContext &gctx, const o2::detectors::DetMatrixCache &cache, double toleranceCm=1e-3, SensorPathProvider pathProvider={})
o2::framework::ServiceSpec	actsGeometryServiceSpec ()
std::vector< o2::framework::ServiceSpec >	defaultServicesWithActsGeometry ()

Typedef Documentation

SensorPathProvider

using o2::acts::SensorPathProvider = typedef std::function<std::string(int sensorID)>

Full TGeo node path of one sensor, e.g. o2::trk::GeometryTGeo::getMatrixPath().

Definition at line 91 of file SurfaceIndexMap.h.

Function Documentation

actsGeometryServiceSpec()

ServiceSpec o2::acts::actsGeometryServiceSpec

(

)

ServiceSpec for ActsGeometryService, to be put into DataProcessorSpec::requiredServices.

Definition at line 55 of file ActsGeometryService.cxx.

defaultServicesWithActsGeometry()

std::vector< ServiceSpec > o2::acts::defaultServicesWithActsGeometry

(

)

CommonServices::defaultServices() plus the ACTS geometry service. Use as the requiredServices of a DataProcessorSpec that wants registry access.

Definition at line 72 of file ActsGeometryService.cxx.

makeSurfaceIndex()

SurfaceIndexMap o2::acts::makeSurfaceIndex	(	const Acts::TrackingGeometry &	geometry,
		const Acts::GeometryContext &	gctx,
		const o2::detectors::DetMatrixCache &	cache,
		double	toleranceCm = 1e-3,
		SensorPathProvider	pathProvider = {}
	)

Build the sensor <-> surface index.

Two strategies, and which one is used matters:

• **With pathProvider (exact, preferred).** Each sensor is resolved to its TGeo node and matched against the node every ACTS surface was built from (ActsPlugins::TGeoDetectorElement::tgeoNode()). This is an identity, not a measurement, so it cannot mis-assign. Repeated placements of one volume share a node and are separated by their accumulated global transform.
• Without it (geometric fallback). Sensors are matched on their local-to-global transform. Exact where a transform identifies a sensor, but it does not always: an ALICE 3 vertex-detector petal is a tube segment, so all three of its layers share one origin and one rotation and differ only in radius, which the matrix cache does not carry. Such sensors are reported as ambiguous rather than assigned arbitrarily.

Both read the same TGeo tree that the surfaces were built from, so a successful match is exact rather than approximate; toleranceCm only guards floating-point round-trips.

Parameters

geometry	the constructed tracking geometry
gctx	context used to evaluate the surface transforms
cache	detector geometry helper; requires a filled L2G cache (call fillMatrixCache(bit2Mask(o2::math_utils::TransformType::L2G)))
toleranceCm	matching tolerance, in O2 units (cm)
pathProvider	optional TGeo path lookup, as described above

Exceptions

std::runtime_error

if a sensor cannot be matched, if a match is ambiguous, or if two sensors would claim the same surface

Definition at line 298 of file SurfaceIndexMap.cxx.