Class Acts::VolumeMaterialMapper

class VolumeMaterialMapper


This is the main feature tool to map material information from a 3D geometry onto the TrackingGeometry with its surface material description.

The process runs as such:

1) TrackingGeometry is parsed and for each Volume with ProtoVolumeMaterial a local store is initialized the identification is done hereby through the Volume::GeometryIdentifier

2) A number of N material tracks is read in, each track has : origin, direction, material steps (< position, step length, x0, l0, a, z, rho >, thichness)

for each track: volume along the origin/direction path are collected. the step are then associated to volume inside which they are. Additional step are created along the track direction.

3) Each ‘hit’ bin per event is counted and averaged at the end of the run

Public Types

using StraightLinePropagator = Propagator<StraightLineStepper, Navigator>

Public Functions

VolumeMaterialMapper() = delete

Delete the Default constructor.

VolumeMaterialMapper(const Config &cfg, StraightLinePropagator propagator, std::unique_ptr<const Logger> slogger = getDefaultLogger("VolumeMaterialMapper", Logging::INFO))

Constructor with config object.

  • cfg – Configuration struct

  • propagator – The straight line propagator

  • slogger – The logger

State createState(const GeometryContext &gctx, const MagneticFieldContext &mctx, const TrackingGeometry &tGeometry) const

helper method that creates the cache for the mapping

This method takes a TrackingGeometry, finds all surfaces with material proxis and returns you a Cache object tO be used

  • gctx[in] The geometry context to use

  • mctx[in] The magnetic field context to use

  • tGeometry[in] The geometry which should be mapped

void finalizeMaps(State &mState) const

Method to finalize the maps.

It calls the final run averaging and then transforms the Homogeneous material into HomogeneousVolumeMaterial and the 2D and 3D grid into a InterpolatedMaterialMap



void mapMaterialTrack(State &mState, RecordedMaterialTrack &mTrack) const

Process/map a single track.


the RecordedMaterialSlab of the track are assumed to be ordered from the starting position along the starting direction

  • mState – The current state map

  • mTrack – The material track to be mapped

struct Config

Nested Configuration struct for the material mapper.

Public Members

float mappingStep = 1.

Size of the step for the step extrapolation.

struct State

Nested State struct which is used for the mapping prococess.

Public Functions

inline State(const GeometryContext &gctx, const MagneticFieldContext &mctx)

Constructor of the Sate with contexts.

Public Members

std::reference_wrapper<const GeometryContext> geoContext

Reference to the geometry context for the mapping.

std::map<const GeometryIdentifier, Grid2D> grid2D

The 2D material grid for each geometry ID.

std::map<const GeometryIdentifier, Grid3D> grid3D

The 3D material grid for each geometry ID.

std::map<const GeometryIdentifier, Acts::AccumulatedVolumeMaterial> homogeneousGrid

The recorded material per geometry ID.

std::reference_wrapper<const MagneticFieldContext> magFieldContext

Reference to the magnetic field context.

std::map<const GeometryIdentifier, BinUtility> materialBin

The binning for each geometry ID.

std::map<GeometryIdentifier, std::shared_ptr<const ISurfaceMaterial>> surfaceMaterial

The surface material of the input tracking geometry.

std::map<const GeometryIdentifier, std::function<Acts::Vector2(Acts::Vector3)>> transform2D

The recorded 2D transform associated the grid for each geometry ID.

std::map<const GeometryIdentifier, std::function<Acts::Vector3(Acts::Vector3)>> transform3D

The recorded 3D transform associated the material grid for each geometry ID.

std::map<GeometryIdentifier, std::unique_ptr<const IVolumeMaterial>> volumeMaterial

The created volume material from it.