Acts::AdaptiveGridTrackDensity Class Reference

Implements a 1D (no time seeding) / 2D (time seeding) grid that is filled with track densities. More...

#include <Acts/Vertexing/AdaptiveGridTrackDensity.hpp>

Classes
struct	Config
	The configuration struct. More...

Public Types
using	Bin = std::pair<std::int32_t, std::int32_t>
	The first (second) integer indicates the bin's z (t) position.
using	DensityMap = boost::container::flat_map<Bin, float>
	Mapping between bins and track densities.
using	GridSizeRange
	Optional grid size range.
using	ZTPosition = std::pair<double, double>
	Coordinates in the z-t plane; the t value will be set to 0 if time vertex seeding is disabled.
using	ZTPositionAndWidth = std::pair<ZTPosition, double>
	z-t position of a maximum and its width

Public Member Functions
	AdaptiveGridTrackDensity (const Config &cfg)
	Constructor.
DensityMap	addTrack (const BoundTrackParameters &trk, DensityMap &mainDensityMap) const
	Adds a single track to the overall grid density.
Result< ZTPosition >	getMaxZTPosition (DensityMap &densityMap) const
	Returns the z and t coordinate of maximum (surrounding) track density.
Result< ZTPositionAndWidth >	getMaxZTPositionAndWidth (DensityMap &densityMap) const
	Returns the z-t position of maximum track density and the estimated z-width of the maximum.
void	subtractTrack (const DensityMap &trackDensityMap, DensityMap &mainDensityMap) const
	Removes a track from the overall grid density.

Static Public Member Functions
static double	getBinCenter (std::int32_t bin, double binExtent)
	Calculates the bin center from the bin number.

Detailed Description

Implements a 1D (no time seeding) / 2D (time seeding) grid that is filled with track densities.

Each track is modelled by a 2D / 3D Gaussian distribution in the d0-z0 / d0-z0-t0 plane, which is evaluated at d0=0. Therefore, each track effectively lives in 1D / 2D. The position of the highest track density (of either a single bin or the sum of a certain region) can be determined. Single tracks can be cached and removed from the overall density. Unlike in the GaussianGridTrackDensity, the overall density map grows adaptively when tracks densities are added to the grid.

Member Typedef Documentation

Bin

using Acts::AdaptiveGridTrackDensity::Bin = std::pair<std::int32_t, std::int32_t>

The first (second) integer indicates the bin's z (t) position.

DensityMap

using Acts::AdaptiveGridTrackDensity::DensityMap = boost::container::flat_map<Bin, float>

Mapping between bins and track densities.

GridSizeRange

using Acts::AdaptiveGridTrackDensity::GridSizeRange

Initial value:

 
      std::pair<std::optional<std::uint32_t>, std::optional<std::uint32_t>>

Optional grid size range.

ZTPosition

using Acts::AdaptiveGridTrackDensity::ZTPosition = std::pair<double, double>

Coordinates in the z-t plane; the t value will be set to 0 if time vertex seeding is disabled.

ZTPositionAndWidth

using Acts::AdaptiveGridTrackDensity::ZTPositionAndWidth = std::pair<ZTPosition, double>

z-t position of a maximum and its width

Constructor & Destructor Documentation

AdaptiveGridTrackDensity()

Acts::AdaptiveGridTrackDensity::AdaptiveGridTrackDensity ( const Config & cfg )

explicit

Constructor.

Parameters

cfg	The configuration parameters

Member Function Documentation

addTrack()

DensityMap Acts::AdaptiveGridTrackDensity::addTrack	(	const BoundTrackParameters &	trk,
		DensityMap &	mainDensityMap ) const

Adds a single track to the overall grid density.

Parameters

trk	The track to be added
mainDensityMap	Map between bins and corresponding density

Returns

The density map of the track that was added

getBinCenter()

double Acts::AdaptiveGridTrackDensity::getBinCenter ( std::int32_t bin, double binExtent )

static

Calculates the bin center from the bin number.

Parameters

bin	Bin number
binExtent	Bin extent

Returns

Bin center

getMaxZTPosition()

Result< ZTPosition > Acts::AdaptiveGridTrackDensity::getMaxZTPosition

(

DensityMap &

densityMap

)

const

Returns the z and t coordinate of maximum (surrounding) track density.

Note

if time vertex seeding is not enabled, the t coordinate will be set to 0.

Parameters

densityMap

Map between bins and corresponding density values

Returns

The z and t coordinates of maximum track density

getMaxZTPositionAndWidth()

Result< ZTPositionAndWidth > Acts::AdaptiveGridTrackDensity::getMaxZTPositionAndWidth

(

DensityMap &

densityMap

)

const

Returns the z-t position of maximum track density and the estimated z-width of the maximum.

Parameters

densityMap

Map between bins and corresponding density values

Returns

The z-t position of the maximum track density and its width

subtractTrack()

void Acts::AdaptiveGridTrackDensity::subtractTrack	(	const DensityMap &	trackDensityMap,
		DensityMap &	mainDensityMap ) const

Removes a track from the overall grid density.

Parameters

trackDensityMap

Map between bins and corresponding density

Note

The track density comes from a single track

Parameters

mainDensityMap

Map between bins and corresponding density

Note

The track density comes from an arbitrary number of tracks