Acts::Experimental::GraphBasedTrackSeeder::Config Struct Reference

Configuration struct for the GBTS seeding algorithm. More...

#include <Acts/Seeding/GraphBasedTrackSeeder.hpp>

Inheritance diagram for Acts::Experimental::GraphBasedTrackSeeder::Config:

Public Attributes
bool	addTriplets = false
	optionally add 3 sp seeds within a certain eta range
bool	beamSpotCorrection = false
	Enable beam spot correction.
bool	calibrateStrips = true
	Resolve a doublet's strip endpoints against its own direction before cutting on them.
std::uint32_t	ccaMaxIterations = 15
	Maximum number of connected-component iterations.
float	curvatureSplitAbsTau = 4.0f
	|cot(theta)| separating the two curvature cuts, |eta| of about 2.1.
float	cutDCurvMax = 0.001f
	Maximum allowed curvature tolerance for candidate edge connections.
float	cutDPhiMax = 0.012f
	Maximum difference in allowed tangent between candidate edge connection.
float	d0Max = 3.0 * UnitConstants::mm
	Maximum d0 impact parameter when validating edge connection triplet.
bool	doubletFilterRZ = true
	Apply RZ cuts on doublets.
float	edgeMaskMinEta = 1.5
	Minimum eta for edge masking.
float	hitShareThreshold = 0.49
	Threshold for hit sharing between seeds.
bool	matchBeforeCreate = false
	Match seeds before creating them.
std::int32_t	matchBeforeCreateMaxBarrelOrder = 1
	Highest pixel barrel layer, counted inside out, matchBeforeCreate applies to when it is enabled.
std::uint32_t	matchBeforeCreateMaxEdges = 2
	Incoming edge count below which a node is accepted without a tau match.
float	maxAbsEtaAddTriplets = 1.5
	the maximum allowed eta value in which three spacepoint seeds are passed through
float	maxAbsTau = 36.0f
	Largest |cot(theta)| accepted for a doublet.
float	maxCurvatureHighEta = 4.75e-4f / UnitConstants::mm
	Maximum |curvature| above curvatureSplitAbsTau, before that scaling.
float	maxCurvatureLowEta = 3.75e-4f / UnitConstants::mm
	Maximum |curvature| below curvatureSplitAbsTau, before that scaling.
float	maxEndcapClusterWidth = 0.35f * Acts::UnitConstants::mm
	Maximum endcap cluster width.
float	maxInvRadDiff = 0.7e-2 / UnitConstants::m
	Max allowed curvature for seed self consistency check.
float	maxOuterRadius = 550.0f
	Maximum radius of pixel detector.
float	maxSeedSplitEta = 0.6
	Max seed eta value considered for splitting.
std::uint32_t	maxSplitSeedSize = 5
	Largest seed size that is split.
float	maxStripLengthFraction = 1.1f
	How far along a strip a crossing may land and still be recovered, as a multiple of the strip half-length, so 1 is the strip itself.
float	maxZ0 = 600
	Maximum z0 value. In pixel mode the value is picked from the RoI.
float	minDeltaRadius = 2.0 * Acts::UnitConstants::mm
	Minimum delta radius between layers.
float	minPt = 1.0f * UnitConstants::GeV
	Minimum transverse momentum.
std::uint32_t	minSeedLevel = 3
	Chain length a seed candidate must reach: a triplet plus one confirmation.
std::uint32_t	minSplitSeedSize = 4
	Smallest seed size that is split into drop-out candidates.
float	minZ0 = -600
	Minimum z0 value. In pixel mode the value is picked from the RoI.
float	moduleEdgeTolerance = 0.3f * Acts::UnitConstants::mm
	Distance to the module edge below which a cluster may be shortened, which switches to the tau lookup table's near-edge bounds.
float	moduleHalfLengthY = 10.0f * Acts::UnitConstants::mm
	Half-length in local y of a pixel module, against which the distance of a cluster to the module edge is measured.
std::uint32_t	nMaxEdges = 2000000
	Maximum number of Gbts edges/doublets.
float	nMaxPhiSlice = 53
	Maximum number of phi slices.
float	phiIndexMargin = 1.5f
	Multiples of the phi slice width duplicated either side of the wrap-around, so a sliding window never has to wrap.
std::uint32_t	phiSortBuckets = 31
	Buckets used to sort an eta bin by phi, at most GbtsNodeStorage::kMaxPhiSortBuckets.
float	phiWindowFarOffset = 0.015f
	Phi window above phiWindowSplitDeltaRadius, in the same form.
float	phiWindowFarSlope = 2.2e-4f / UnitConstants::mm
	Slope of the far phi window, per unit radial separation.
float	phiWindowNearOffset = 0.002f
	Phi window below phiWindowSplitDeltaRadius, as offset plus slope times the radial separation.
float	phiWindowNearSlope = 4.33e-4f / UnitConstants::mm
	Slope of the near phi window, per unit radial separation.
float	phiWindowSplitDeltaRadius = 60.0f * UnitConstants::mm
	Radial separation splitting the two phi window slopes below.
detail::GbtsTauLookupTable	tauLookupTable
	Accepted tau range per cluster width bin, needed by the cluster width cuts and ignored without them.
float	tauLutBinWidth = 0.05f * Acts::UnitConstants::mm
	Cluster width covered by one bin of the tau lookup table.
float	tauRatioCorr = 0.006
	correction applied to tau acceptance if a layer is missed during edge connecting
float	tauRatioCorrStrip = 0.03f
	The same for a triplet any of whose three nodes a strip module made, whose two doublets resolved the shared node's along-strip coordinate separately.
float	tauRatioCut = 0.007
	Tau ratio cut threshold.
float	tauRatioPrecut = 0.009f
	Tau ratio precut threshold.
float	tripletPtFraction = 0.8f
	Fraction of minPt a triplet may fall to, allowing for three-point pT resolution.
float	tuningPt = 0.9f * UnitConstants::GeV
	pT the default cut coefficients were tuned at; they scale by tuningPt / minPt.
bool	useAdaptiveCuts = true
	widens allowed variation in tau ratio if layer is missed in edge connecting
bool	useClusterWidthCuts = false
	Enable the cluster width cuts: wide endcap rejection and tau narrowing.
bool	useEtaBinning = true
	Use eta binning from geometry structure.
bool	useStripConnections = false
	Take the strip-to-strip layer connections from the connector file instead of the pixel-to-pixel ones.
bool	validateTriplets = true
	optional validation for barrel triplets
std::int32_t	z0HistogramMaxBarrelOrder = 0
	Highest pixel barrel layer, counted inside out, whose nodes are cut against the z0 histogram of their outer neighbourhood and whose isolated nodes are skipped.
float	z0Resolution = 2.5f * UnitConstants::mm
	Half-width of the z0 window a node is matched against in the histogram.

Detailed Description

Configuration struct for the GBTS seeding algorithm.

Member Data Documentation

addTriplets

bool Acts::Experimental::GraphBasedTrackSeeder::Config::addTriplets = false

optionally add 3 sp seeds within a certain eta range

Note

Worth little until maxAbsEtaAddTriplets is opened past edgeMaskMinEta; matters most where there are few layers.

calibrateStrips

bool Acts::Experimental::GraphBasedTrackSeeder::Config::calibrateStrips = true

Resolve a doublet's strip endpoints against its own direction before cutting on them.

Nothing is written back; the correction is the pair's.

matchBeforeCreateMaxBarrelOrder

std::int32_t Acts::Experimental::GraphBasedTrackSeeder::Config::matchBeforeCreateMaxBarrelOrder = 1

Highest pixel barrel layer, counted inside out, matchBeforeCreate applies to when it is enabled.

Negative disables it.

maxAbsTau

float Acts::Experimental::GraphBasedTrackSeeder::Config::maxAbsTau = 36.0f

Largest |cot(theta)| accepted for a doublet.

The default corresponds to |eta| of about 4.3, beyond the acceptance of any current tracker.

maxStripLengthFraction

float Acts::Experimental::GraphBasedTrackSeeder::Config::maxStripLengthFraction = 1.1f

How far along a strip a crossing may land and still be recovered, as a multiple of the strip half-length, so 1 is the strip itself.

The same quantity as TripletSeedFinder::Config::toleranceParam.

phiWindowFarSlope

float Acts::Experimental::GraphBasedTrackSeeder::Config::phiWindowFarSlope = 2.2e-4f / UnitConstants::mm

Slope of the far phi window, per unit radial separation.

Scaled by tuningPt / minPt.

phiWindowNearSlope

float Acts::Experimental::GraphBasedTrackSeeder::Config::phiWindowNearSlope = 4.33e-4f / UnitConstants::mm

Slope of the near phi window, per unit radial separation.

Scaled by tuningPt / minPt.

tauRatioCorrStrip

float Acts::Experimental::GraphBasedTrackSeeder::Config::tauRatioCorrStrip = 0.03f

The same for a triplet any of whose three nodes a strip module made, whose two doublets resolved the shared node's along-strip coordinate separately.

Reaches nothing without a strip in the triplet.

useStripConnections

bool Acts::Experimental::GraphBasedTrackSeeder::Config::useStripConnections = false

Take the strip-to-strip layer connections from the connector file instead of the pixel-to-pixel ones.

Read where the file is loaded, not by the seeder itself.

z0HistogramMaxBarrelOrder

std::int32_t Acts::Experimental::GraphBasedTrackSeeder::Config::z0HistogramMaxBarrelOrder = 0

Highest pixel barrel layer, counted inside out, whose nodes are cut against the z0 histogram of their outer neighbourhood and whose isolated nodes are skipped.

Negative disables the cut.