Acts Namespace Reference

The main namespace encompassing all ACTS code. More...

Namespaces
namespace	DetrayJsonHelper
namespace	Experimental
	Contains code that is not considered stable yet and might change.
namespace	GridAxisGenerators
	Axis generators are used to allow defining different grid types for indexed geometry objects.
namespace	ParticleIdHelper
	Particle identification based on PDG number.
namespace	PhysicalConstants
	Physical constants in native units.
namespace	UnitConstants
	Constants and helper literals for physical units.
namespace	UnitLiterals
	Namespace for user-defined literals for physical units.

Classes
class	AccumulatedMaterialSlab
	Accumulate material properties from multiple hits/track and multiple tracks. More...
class	AccumulatedSurfaceMaterial
	This class is used by the SurfaceMaterialMapper in order to accumulate/collect material information during the mapping process. More...
class	AccumulatedVolumeMaterial
	Accumulate and average volume-based material properties. More...
struct	ActorHasResultStruct
	Helper struct exposing ActorHasResult as a boolean. More...
struct	ActorList
	ActorList implementation to be used with the propagator. More...
struct	ActorResultTypeExtractor
	Extract the result type of an actor. More...
class	AdaptiveGridDensityVertexFinder
	Vertex finder that makes use of a track density grid. More...
class	AdaptiveGridTrackDensity
	Implements a 1D (no time seeding) / 2D (time seeding) grid that is filled with track densities. More...
class	AdaptiveMultiVertexFinder
	Implements an iterative vertex finder. More...
class	AdaptiveMultiVertexFitter
	Implements an adaptive multi-vertex fitter as described in detail in Section 5.3.5 in: Ref. More...
class	AmbiguityResolutionML
	Generic implementation of the machine learning ambiguity resolution Contains method for data preparations. More...
class	AnnealingUtility
	Implements a deterministic thermodynamic annealing scheme Ref. More...
class	AnnulusBounds
	Class that implements a (potentially asymmetric) bounds with difference between surface bound center and surface coordinate center. More...
class	AnyBase
	Small opaque type-erased type with configurable small buffer optimization. More...
class	AnyBaseAll
	Base class for all instances of AnyBase regarfless of SBO size. More...
class	AnyGridConstView
	Type-safe view into a grid with const access. More...
class	AnyGridView
	Type-safe view into a grid with mutable access. More...
struct	AnySurfaceReached
	Aborter that checks if the propagation has reached any surface. More...
class	AnyTrack
class	AnyTrackProxy
	Type-erased track object This class provides a type-erased interface to track proxies without requiring heap allocation per instance. More...
class	AnyTrackStateProxy
	Type-erased track state proxy for any trajectory backend. More...
class	AppendOnlyNavigationStream
	Append-only helper to add candidates to a navigation stream. More...
class	ApproachDescriptor
	Virtual base class to decide and return which approaching surface to be taken, the surfaces are std::shared_ptr, as they can be the boundary surfaces of the representingVolume of the Layer. More...
class	AssertionFailureException
	Exception type for assertion failures This class captures the information available to the throw_assert macro. More...
class	AtlasStepper
	the AtlasStepper implementation for the More...
class	AveragingScopedTimer
	A timer class that measures and averages execution times of multiple samples. More...
class	Axis
	calculate bin indices from a given binning structure More...
class	Axis< AxisType::Equidistant, bdt >
	calculate bin indices for an equidistant binning More...
class	Axis< AxisType::Variable, bdt >
	calculate bin indices for a variable binning More...
class	AxisAlignedBoundingBox
	Implementation of an Axis Aligned Bounding Box. More...
struct	AxisBoundaryTypeTag
	Tag helper type for Axis constructors with class template deduction. More...
struct	AxisDirectionReferenceGenerator
	A struct to access reference positions based on bin values. More...
class	BarrelEndcapAssembler
	Fluent builder that assembles a combined barrel + endcap subdetector into a CylinderContainerBlueprintNode arranged along the Z axis. More...
class	BasePropagator
	Common simplified base interface for propagators. More...
class	BetheHeitlerApprox
	Interface for Bethe-Heitler Gaussian mixture approximations. More...
class	BetheHeitlerApproxSingleCmp
	This class approximates the Bethe-Heitler with only one component. More...
class	BinnedArray
	Pure virtual base class for Binned Array to avoid map searches. More...
class	BinnedArrayXD
	Avoiding a map search, the templated BinnedArray class can help ordereing geometrical objects by providing a dedicated BinUtility. More...
class	BinnedGroup
class	BinnedGroupIterator
	Iterator over a binned group grid neighborhood. More...
class	BinnedSurfaceMaterial
	It extends the ISurfaceMaterial base class and is an array pf MaterialSlab. More...
class	BinnedSurfaceMaterialAccumulator
	The binned surface material accumulator. More...
class	BinningData
	This class holds all the data necessary for the bin calculation. More...
class	BinUtility
	The BinUtility class that translated global and local position into a bins of a BinnedArray, most performant is equidistant binning without a transform, however, optionally a transform can be provided, e.g. More...
class	Blueprint
	This class is the top-level entry point to build a tracking geometry using the blueprint building mechanism. More...
class	BlueprintBuilder
	High-level builder that converts a backend detector element hierarchy into a blueprint node tree. More...
class	BlueprintNode
	Base class for all nodes in the blueprint tree. More...
struct	BlueprintOptions
	Options controlling blueprint navigation policies. More...
class	BoundarySurfaceT
class	BoundaryTolerance
	Variant-like type to capture different types of boundary tolerances. More...
class	BoundFactory
	Factory helper class to construct volume or surface bounds where the constructed bounds are cached inside the factory and if the same bound parameters are requested at a later stage the factory automatically returns the cached bounds. More...
struct	BoundParameterRecorder
	Collector of the bound track parameters. More...
class	BoundTrackParameters
	Track parameters bound to a reference surface for a single track. More...
struct	BremCombinatorialKalmanFilterOptions
	Options for the combinatorial Kalman filter with bremsstrahlung recovery. More...
class	BroadTripletSeedFilter
	Triplet seed filter used in the triplet seeding algorithm. More...
class	CalibrationContext
	This is the central definition of the Acts payload object regarding detector calibration. More...
class	CartesianSpacePointGrid
	A cartesian space point grid used for seeding in a cartesian detector geometry. More...
struct	CenterReferenceGenerator
	A struct to access the center position as a sole reference. More...
class	ChargeHypothesis
	Charge and momentum interpretation for arbitrarily charged particles. More...
class	CloneablePtr
	A copyable smart pointer that uses a cloner function to copy the managed object. More...
struct	Color
	Struct describing a color. More...
class	CombinatorialKalmanFilter
	Combinatorial Kalman filter to find tracks. More...
struct	CombinatorialKalmanFilterExtensions
	Extension struct which holds the delegates to customize the CKF behavior. More...
struct	CombinatorialKalmanFilterOptions
	Combined options for the combinatorial Kalman filter. More...
struct	CombinatorialKalmanFilterResult
	Result container for the combinatorial Kalman filter actor. More...
class	CompositePortalLink
	Composite portal links can graft together other portal link instances, for example grids that could not be merged due to invalid binnings. More...
class	ConeBounds
	Bounds for a conical surface, the opening angle is stored in \( \tan(\alpha) \) and always positively defined. More...
class	ConeLayer
	Class to describe a conical detector layer for tracking, it inherits from both, Layer base class and ConeSurface class. More...
class	ConeSurface
	Class for a conical surface in the Tracking geometry. More...
class	ConeVolumeBounds
	Volume bound class for describing conical volumes either with cylindrical inlay or outer boundary, it also allows for a sectoral description. More...
class	ConstantBField
	The simplest magnetic field implementation is a constant field, which returns the same field values at every queried location. More...
class	ConstrainedStep
	A constrained step class for the steppers. More...
struct	ConstRefHolder
	Non-owning holder for referencing a backend with const access. More...
class	ConstVectorMultiTrajectory
	Const version of VectorMultiTrajectory. More...
class	ConstVectorTrackContainer
	Read-only vector-backed track container. More...
class	ContainerBlueprintNode
	A blueprint node that can contain multiple child volumes. More...
class	ConvexPolygonBounds
	This is the actual implementation of the bounds. More...
class	ConvexPolygonBounds< PolygonDynamic >
	This is the specialization handling a polygon with a dynamic number of points. More...
class	ConvexPolygonBoundsBase
	base class for convex polygon bounds More...
class	CuboidContainerBlueprintNode
	Container blueprint node stacking cuboid volumes. More...
class	CuboidPortalShell
	Base class for cuboid shaped portal shells, e.g. More...
class	CuboidStackPortalShell
	This class describes a cuboid shell containing multiple volumes. More...
class	CuboidVolumeBounds
	Bounds for a cubical Volume, the orientedSurfaces(...) method creates a vector of 6 surfaces: More...
class	CuboidVolumeBuilder
	This class builds a box detector with a configurable amount of surfaces in it. More...
class	CuboidVolumeStack
	This class implements a x-. More...
class	CurvilinearSurface
	Utility class for curvilinear surfaces. More...
class	CutoutCylinderVolumeBounds
	Class which implements a cutout cylinder. More...
class	CylinderBounds
class	CylinderContainerBlueprintNode
	Container blueprint node stacking cylindrical volumes. More...
class	CylinderLayer
	Class to describe a cylindrical detector layer for tracking, it inherits from both, Layer base class and CylinderSurface class. More...
class	CylinderNavigationPolicy
	Optimized navigation policy for cylindrical volumes that intelligently selects which portals to add as candidates based on geometric analysis. More...
class	CylinderPortalShell
	Base class for cylinder shaped portal shells, e.g. More...
class	CylinderStackPortalShell
	This class describes a cylinder shell containing multiple volumes. More...
class	CylinderSurface
	Class for a CylinderSurface in the TrackingGeometry. More...
class	CylinderVolumeBounds
	[0] and [1] at positive \( \phi \) More...
class	CylinderVolumeBuilder
	A volume builder to be used for building concentric cylinder volumes. More...
class	CylinderVolumeHelper
	The concrete implementation for cylindrical TrackingVolume objects of the ITrackingVolumeCreator interface. More...
class	CylinderVolumeStack
	This class implements a z-aligned or r-aligned stack of cylinder volumes with synchronized bounds. More...
class	CylindricalSpacePointGrid
	A cylindrical space point grid used for seeding in a cylindrical detector geometry. More...
class	DBScan
	A general implementation of an N dimensional DBScan clustering algorithm. More...
class	Delegate
class	Delegate< R(Args...), H, O >
	Delegate type that allows type erasure of a callable without allocation and with a single level of indirection. More...
struct	DelegateFuncTag
	Tag type to select a compile-time callable for Delegate. More...
class	DiamondBounds
class	DiamondPortalShell
	Base class for diamond shaped portal shells, e.g single volumes with polygon shape or stacked (multiple) volumes (TODO). More...
class	DiamondVolumeBounds
	Bounds for a polygonal prism shaped Volume, the orientedSurface(...) method creates a vector of 8 surfaces: 2 Diamond Shape Surfaces (see. More...
struct	DirectedProtoAxis
	A Directed proto axis. More...
class	Direction
	The direction is always with respect to a given momentum, surface normal or other general axes. More...
class	DirectNavigator
	A fully guided navigator. More...
class	DiscBounds
class	DiscLayer
	Class to describe a disc-like detector layer for tracking, it inherits from both, Layer base class and DiscSurface class. More...
class	DiscSurface
	Class for a disc surface (or a segment thereof). More...
class	DiscTrapezoidBounds
	Class to describe the bounds for a planar DiscSurface. More...
class	DistanceSorterT
	This will check on absolute distance. More...
class	DoubletSeedFinder
	Interface and a collection of standard implementations for a doublet seed finder. More...
class	DoubletsForMiddleSp
	Container for doublets found by the doublet seed finder. More...
class	DummyVertexFitter
	Dummy vertex fitter class, only to be used for ensuring interfaces where a vertex fitter type is required but no fitter is actually needed. More...
class	EigenStepper
	Runge-Kutta-Nystroem stepper based on Eigen implementation for the following ODE: More...
struct	EigenStepperDefaultExtension
	Default evaluator of the k_i's and elements of the transport matrix D of the RKN4 stepping. More...
struct	EigenStepperDenseExtension
	Evaluator of the k_i's and elements of the transport matrix D of the RKN4 stepping. More...
class	ElementFraction
	Memory-efficient storage of the relative fraction of an element. More...
class	ElementLayerAssembler
	Fluent builder that assembles a flat collection of cylindrical or disc-like detector layers from layer-representative detector elements into a CylinderContainerBlueprintNode. More...
class	EllipseBounds
struct	EndOfWorldReached
	This is the condition that the end of world has been reached it then triggers an propagation abort. More...
struct	EstimateTrackParamCovarianceConfig
	Configuration for the estimation of the covariance matrix of the track parameters with estimateTrackParamCovariance. More...
struct	EventDataView3D
	Utilities to visualize event data in 3D. More...
struct	ExpSafeLimit
	Specialization of the exponent limit to be used for safe exponential, depending on the floating point type. More...
struct	ExpSafeLimit< double >
	Safe exponent limits for double precision. More...
struct	ExpSafeLimit< float >
	Safe exponent limits for single precision. More...
class	Extent
	A class representing the geometric extent of an object in its possible dimensions, these can be all dimensions that are described as AxisDirections. More...
struct	ExtentEnvelope
	This struct models a multi-dimensional enveloper along the axis directions. More...
class	FiniteStateMachine
	Implementation of a finite state machine engine. More...
class	FixedSubspaceHelper
	Helper class for fixed subspace operations. More...
struct	ForcedSurfaceReached
	Similar to SurfaceReached, but with an infinite overstep limit. More...
class	FreeTrackParameters
	Track parameters not bound to a surface for a single track. More...
class	Frustum
	Class representing a frustum shape. More...
class	FsmwMode1dFinder
	Calculates the mode of a unidimenensional distribution using the Fraction of Sample Mode with Weights algorithm For reference, see: On a Fast, Robust Estimator of the Mode: Comparisons to Other Robust Estimators with Applications, David R. More...
class	FullBilloirVertexFitter
	Vertex fitter class implementing the Billoir vertex fitter. More...
class	GainMatrixSmoother
	Kalman trajectory smoother based on gain matrix formalism. More...
class	GainMatrixUpdater
	Kalman update step using the gain matrix formalism. More...
class	GaussianGridTrackDensity
	Implements a 1-dim density grid to be filled with track Gaussian distributions. More...
struct	GaussianSumFitter
	Gaussian Sum Fitter implementation. More...
class	GaussianTrackDensity
	Class to model tracks as 2D density functions based on their d0 and z0 perigee parameters (mean value) and covariance matrices (determining the width of the function). More...
class	GenericApproachDescriptor
	Class to decide and return which approaching surface to be taken, it's a generic descriptor for n surfaces. More...
class	GenericCuboidVolumeBounds
	Volume bounds described by eight arbitrary cuboid vertices. More...
class	GeometryContext
	This is the central definition of the Acts payload object regarding detector geometry status (e.g. More...
struct	GeometryContextOstreamWrapper
	Helper struct that stores an object and a context, and will print it to an outstream. More...
class	GeometryHierarchyMap
	Store values mapped into the geometry hierarchy. More...
class	GeometryHierarchyMapJsonConverter
	Convert a geometry hierarchy map to/from Json. More...
class	GeometryIdentifier
	Identifier for geometry nodes within the geometry hierarchy. More...
class	GeometryIdentifierBlueprintNode
	Blueprint node for configuring and applying geometry identifiers to volumes. More...
struct	GeometryIdentifierHook
	Base class for hooks that can be used to modify the Geometry Identifier during construction. More...
class	GeometryObject
	Base class to provide GeometryIdentifier interface: More...
class	GeometryObjectSorterT
	Sorter functor for geometry objects by reference position. More...
struct	GeometryView3D
	Helper utilities for drawing geometry in 3D views. More...
struct	GloballyIndexedMaterialAccessor
	This is an accessor for cases where the material is filled in a global material vector that is accessed from the different material grids. More...
class	GlueVolumesDescriptor
	Descriptor class to hold GlueVolumes of a TrackingGeometry object. More...
class	GreedyAmbiguityResolution
	Evicts tracks that seem to be duplicates or fakes. More...
class	Grid
	class for describing a regular multi-dimensional grid More...
class	GridBinFinder
class	GridDensityVertexFinder
	Vertex finder that makes use of a track density grid. More...
class	GridGlobalIterator
	Grid iterator using the global position. More...
class	GridLocalIterator
	Grid iterator using the local position. More...
struct	GridMaterialAccessor
	This is an accessor for cases where the material is directly stored in the grid, it simply forwards the grid entry in const and non-const way. More...
class	GridPortalLink
	GridPortalLink implements a subdivided surface where the target volume depends on the position on the surface. More...
class	GridPortalLinkT
	Concrete class deriving from GridPortalLink that boxes a concrete grid for lookup. More...
class	GridSurfaceMaterialT
	GridSurfaceMaterialT. More...
struct	GsfComponent
	Encapsulates a component of a Gaussian mixture as used by the GSF. More...
struct	GsfExtensions
	The extensions needed for the GSF. More...
struct	GsfOptions
	Options for configuring the Gaussian-sum filter fit. More...
class	HelicalTrackLinearizer
	Linearizes the track parameters at the PCA to a user-provided point (linPoint). More...
class	HomogeneousSurfaceMaterial
	It extends the ISurfaceMaterial virtual base class to describe a simple homogeneous material on a surface. More...
class	HomogeneousVolumeMaterial
	It extends the IVolumeMaterial base class to describe a simple homogeneous material in a volume. More...
class	HoughVertexFinder
	Implements the vertex finder based on the space points using Hough transform For more information, see arXiv:2410.14494 0. More...
class	IAssignmentFinder
	Interface for the material mapping that seeks the possible assignment candidates for the material interactiosn. More...
class	IAxis
	Common base class for all Axis instances. More...
class	IConfinedTrackingVolumeBuilder
	This is an interface class for constructing TrackingVolumes whose are confined in a mother-TrackingVolume. More...
class	IGrid
	Base class for all grid types. More...
struct	IGridMaterialAccessor
	Base class for material accessors, this is needed for the I/O of the different grid material types, in the actual implementation the material accessor is a template parameter. More...
class	IGridSurfaceMaterial
	Intermediate interface to the grid surface material given access to the grid and the material accessor. More...
class	IGridSurfaceMaterialBase
	Base class for the concrete templated grid surface material types. More...
class	ILayerArrayCreator
	Interface class ILayerArrayCreators, it inherits from IAlgTool. More...
class	ILayerBuilder
	Interface class for ILayerBuilders in a typical | EC- | Central | EC+ | detector setup. More...
class	IMaterialDecorator
	Virtual base class for decorators that allow to load material onto a TrackingGeometry. More...
struct	ImpactParametersAndSigma
	Impact parameters and their uncertainties with optional timing. More...
class	ImpactPointEstimator
	Estimator for impact point calculations A description of the underlying mathematics can be found here: https://github.com/acts-project/acts/pull/2506 TODO: Upload reference at a better place. More...
class	IMultiAxis
	Common base class for all MultiAxis instances. More...
class	IMultiAxisXD
	Common base class for all multi-axes of a fixed, compile-time dimension. More...
class	INavigationPolicy
	Base class for all navigation policies. More...
struct	IndexedMaterialAccessor
	This is an accessor for cases where the material is filled in a vector and then indexed by the grid. More...
class	IndexGrid
	This is an index grid based navigation state updator, it uses an extractor type and a filler type to handle the navigation state. More...
struct	IndexGridFiller
	A helper class that fills surfaces into predefined grids. More...
class	IndexGridNavigationConfig
	Configuration for the index-grid based navigation policy. More...
class	IndexGridNavigationPolicy
	A navigation policy that uses grid based navigation for indexed surfaces Navigate through a multilayer structure by creating an artificial path on the grid. More...
class	InfiniteBounds
	templated boundless extension to forward the interface Returns all inside checks to true and can templated for all bounds More...
struct	InputTrack
	Type-erased wrapper around an input track pointer. More...
struct	InteractionVolume
	The Material interaction volume struct. More...
struct	InteractionVolumeCollector
	An Interaction volume collector with unique counting. More...
class	InterpolatedBFieldMap
	Interpolates magnetic field value from field values on a given grid. More...
class	InterpolatedMagneticField
	Base class for interpolated magnetic field providers. More...
class	InterpolatedMaterialMap
	Interpolate material classification values from material values on a given grid. More...
class	Intersection
	Intersection struct containing the position, path length and status of an intersection. More...
class	IntersectionMaterialAssigner
	A purely intersection based material assigner on a trial and error basis. More...
struct	IReferenceGenerator
	An interface for reference point generators. More...
struct	IsReadOnlyMultiTrajectory
struct	IsReadOnlyMultiTrajectory< ActsPlugins::ConstPodioTrackStateContainer< holder_t > >
struct	IsReadOnlyMultiTrajectory< ActsPlugins::MutablePodioTrackStateContainer< holder_t > >
struct	IsReadOnlyMultiTrajectory< ConstVectorMultiTrajectory >
struct	IsReadOnlyMultiTrajectory< VectorMultiTrajectory >
struct	IsReadOnlyTrackContainer
struct	IsReadOnlyTrackContainer< ActsPlugins::ConstPodioTrackContainer< holder_t > >
struct	IsReadOnlyTrackContainer< ActsPlugins::MutablePodioTrackContainer< holder_t > >
struct	IsReadOnlyTrackContainer< ConstVectorTrackContainer >
struct	IsReadOnlyTrackContainer< VectorTrackContainer >
class	ISurfaceMaterial
	Base class of all surface-based material description. More...
class	ISurfaceMaterialAccumulator
	Interface for the material mapping, this is the accumulation step. More...
class	IterativeVertexFinder
	Implements an iterative vertex finder. More...
class	ITrackingGeometryBuilder
	Interface class for the TrackingGeometry building, this is used by the TrackingGeometrySvc to build the geometry. More...
class	ITrackingGeometryJsonDecorator
	helper class to add extra information to surface or volume json objects More...
class	ITrackingGeometryVisitor
	Base class for tracking geometry visitors. More...
class	ITrackingVolumeArrayCreator
	Interface class ITrackingVolumeArrayCreators It inherits from IAlgTool. More...
class	ITrackingVolumeBuilder
	Interface class ITrackingVolumeBuilders. More...
class	ITrackingVolumeHelper
	Interface class ITrackingVolumeHelper tools, it inherits from IAlgTool. More...
class	ITripletSeedCuts
	ITripletSeedCuts can be used to increase or decrease seed weights based on the space points used in a seed. More...
class	ITripletSeedFilter
	Interface for triplet seed filtering. More...
class	IVertexFinder
	Common interface for both vertex finders and vertex seed finders. More...
class	IVisualization3D
	Partially abstract base class which provides an interface to visualization helper classes. More...
class	IVolumeMaterial
	Material associated with a Volume (homogeneous, binned, interpolated). More...
class	IVolumeMaterialJsonDecorator
	helper class to add extra information to surface or volume json objects More...
class	JsonDetectorElement
	A implementation of a detector element, that is constructed from a JSON description of a surface. More...
struct	jsonKey
	store in a single place the different key used for the material mapping More...
class	JsonKindDispatcher
	JSON-specific dispatcher that routes decoder functions based on a string kind tag found in the encoded payload. More...
class	JsonMaterialDecorator
	Material decorator from Json format. More...
class	KalmanFitter
	Kalman fitter implementation. More...
struct	KalmanFitterExtensions
	Extension struct which holds delegates to customise the KF behavior. More...
struct	KalmanFitterOptions
	Combined options for the Kalman fitter. More...
struct	KalmanFitterResult
	Result payload returned by the Kalman fitter. More...
class	KDTree
	A general k-d tree with fast range search. More...
class	Layer
	Base Class for a Detector Layer in the Tracking Geometry. More...
class	LayerArrayCreator
	The LayerArrayCreator is a simple Tool that helps to construct LayerArrays from std::vector of Acts::CylinderLayer, Acts::DiscLayer, Acts::PlaneLayer. More...
class	LayerBlueprintNode
	The layer node is essentially an auto-sizing wrapper around a set of surfaces. More...
class	LayerCreator
	The LayerCreator is able to build cylinder disc layers or plane layers from detector elements. More...
class	LinearizedTrack
	Class for linear expansion of track parameters in vicinity of vertex. More...
class	LineBounds
	Bounds for a LineSurface. More...
class	LineSurface
	Base class for a linear surfaces in the TrackingGeometry to describe dirft tube, straw like detectors or the Perigee It inherits from Surface. More...
class	Logger
	class for printing debug output More...
class	MagneticFieldContext
	Context object for lookup of magnetic field values. More...
class	MagneticFieldProvider
	Base class for all magnetic field providers. More...
class	Material
	Material description for interactions with matter. More...
class	MaterialComposition
	Material composed from multiple elements with varying factions. More...
class	MaterialDesignatorBlueprintNode
	This node type registers material proxies into its child volume during the blueprint construction. More...
struct	MaterialInteraction
	The Material interaction struct It records the surface and the passed material This is only necessary recorded when configured. More...
struct	MaterialInteractor
	Material interactor propagator action. More...
class	MaterialMapJsonConverter
	read the material from Json More...
struct	MaterialMapLookup
	Struct for mapping global 3D positions to material values. More...
class	MaterialMapper
	Class that implements the material mapping procedure. More...
class	MaterialSlab
	Material description for an object with defined thickness. More...
struct	MaterialSurface
	selector for finding surface More...
struct	MaterialSurfaceIdentifier
	selector for finding surface More...
class	MaterialValidator
	The material validator is a tool that allows to record the material seen by a ray through a set of material surfaces. More...
struct	MaterialVolume
	selector for finding volume More...
class	MbfSmoother
	Kalman trajectory smoother based on the Modified Bryson–Frazier (mBF) smoother. More...
class	MeasurementSelector
	Measurement selection struct selecting those measurements compatible with the given track parameter against provided criteria on one surface. More...
struct	MeasurementSelectorCuts
	Selection cuts for associating measurements with predicted track parameters on a surface. More...
class	MergedMaterialMarker
	Sentinel surface material used by Portal::merge in its "keep going" mode. More...
struct	MiddleSpInfo
	Derived quantities for the middle space point in a doublet. More...
struct	missing_specialization
class	MultiAxis
	Multi-dimensional binning defined by a product of one-dimensional axes. More...
class	MultiComponentBoundTrackParameters
	This class is only a light wrapper around a surface and a vector of parameters. More...
class	MultiIndex
	A set of (hierarchical) indices bitpacked into a single value. More...
class	MultiIntersection
	Container for up to two intersections in a given dimension. More...
class	MultiLayerNavigationPolicy
	A navigation policy that uses grid based navigation for indexed surfaces Navigate through a multilayer structure by creating an artificial path on the grid. More...
class	MultiNavigationPolicy
	Combined navigation policy that calls all contained other navigation policies. More...
class	MultiRangeBField
	Magnetic field provider modelling a magnetic field consisting of several (potentially overlapping) regions of constant values. More...
class	MultiStepperLoop
	Stepper based on a single-component stepper, but can handle Multi-Component Tracks (e.g., for the GSF). More...
struct	MultiStepperSurfaceReached
	Aborter that stops when all components reach the target surface. More...
class	MultiTrajectory
	Store a trajectory of track states with multiple components. More...
class	MultiWireVolumeBuilder
	A class to build multiwire tracking volumes (e.g wire chambers). More...
struct	MutableProtoLayer
	A mutable proto layer that can be modified after construction. More...
struct	NavigationArguments
	Struct that serves as the argument to the navigation delegate. More...
class	NavigationLayer
	Class to be used for gaps in Volumes as a navigational link. More...
struct	NavigationOptions
	The navigation options for the tracking geometry. More...
class	NavigationPolicyFactory
	Base class for navigation policy factories. More...
class	NavigationPolicyState
	Wrapper class for a navigation policy state stored in the state manager. More...
class	NavigationPolicyStateManager
	Manager class for navigation policy states. More...
class	NavigationStream
	The NavigationStream is a container for the navigation candidates that are currentlu processed in a given context. More...
class	NavigationTarget
	The navigation target. More...
class	Navigator
	Steers the propagation through the geometry by providing the next surface to be targeted. More...
struct	NavigatorPlainOptions
	Plain navigator options carrying geometry context and surfaces. More...
struct	NavigatorStatistics
	A struct to hold statistics of the navigator. More...
class	NeighborHoodIndices
	This object can be iterated to produce up to two sequences of integer indices, corresponding to the half-open integer ranges [begin1, end1[ and [begin2, end2[. More...
class	NullBField
	Null bfield which returns 0 always. More...
class	NumericalTrackLinearizer
	Linearizes the track parameters at the PCA to a user-provided point (linPoint). More...
class	ObjectSorterT
	Sorter functor for geometry objects by axis direction. More...
class	ObjVisualization3D
	This helper produces output in the OBJ format. More...
struct	OrientedSurface
	Helper bundle of a surface and its orientation. More...
struct	OuterStripSpacePointCalibrationDetails
	Collection of outer strip space point details, used for the calibration. More...
struct	OuterStripSpacePointCalibrationDetailsDerived
	Derived collection of outer strip space point details, used for the calibration. More...
struct	overloaded
	Helper struct that can turn a set of lambdas into a single entity with overloaded call operator. More...
class	OwningDelegate
class	OwningDelegate< R(Args...), H >
	Alias for an owning delegate. More...
class	PadBlueprintNode
	Wraps a single child blueprint node and pads it into a larger volume whose dimensions are evaluated at construction time using the child's extent plus a configurable envelope. More...
struct	ParticleData
	Lightweight particle properties description. More...
class	ParticleHypothesis
	Particle hypothesis used in reconstruction. More...
class	PassiveLayerBuilder
	The PassiveLayerBuilder is able to build cylinder & disc layers with given dimensions and material. More...
struct	PathLimitReached
	This is the condition that the pathLimit has been reached. More...
class	PerigeeSurface
	Class describing the Line to which the Perigee refers to. More...
class	PlanarBounds
	common base class for all bounds that are in a local x/y cartesian frame More...
class	PlaneLayer
	Class to describe a planar detector layer for tracking, it inherits from both, Layer base class and PlaneSurface class. More...
class	PlaneSurface
	Class for a planaer in the TrackingGeometry. More...
class	PlyVisualization3D
	Helper to write out PlyVisualization3D visualization format. More...
class	PointBounds
	Bounds for a PointSurface. More...
class	PointSurface
	Surface describing the point of closest approach (PCA) of a track to a single fixed 3D point (the surface center). More...
class	Polyhedron
	Struct which contains a cartesian approximation for any surface type. More...
struct	PolyhedronReferenceGenerator
	A struct to access generated vertices from surface polyhedrons These vertices are then used to find the bin boundary box for the indexed grid. More...
class	PolynomialBetheHeitlerApprox
	This class approximates the Bethe-Heitler distribution as a gaussian mixture. More...
class	Portal
	A portal connects two or more neighboring volumes. More...
class	PortalDesignatorBlueprintNode
	This node type assigns string tags to specific portal faces of its child volume during the blueprint construction. More...
class	PortalFusingException
	Exception thrown when portals cannot be fused. More...
class	PortalLinkBase
	PortalLinkBase is the abstract base class for all portal links. More...
class	PortalMergingException
	Exception thrown when portals cannot be merged. More...
class	PortalShellBase
	The portal shell of a volume is the set of portals that describes connections "outside" of the volume. More...
struct	ProjectedReferenceGenerator
	A Projected reference generator which projects the polyhedron vertices onto a given reference surface. More...
class	Propagator
	Propagator for particles (optionally in a magnetic field). More...
class	PropagatorMaterialAssigner
	A Propagator based material assigner that uses the navigation and transport of the propagator to assign the material to the surface or the volume. More...
struct	PropagatorOptions
	Options for propagate() call. More...
struct	PropagatorPlainOptions
	Holds the generic propagator options. More...
struct	PropagatorResult
	Simple class holding result of propagation call. More...
struct	PropagatorState
	private Propagator state for navigation and debugging More...
struct	PropagatorStatistics
	A struct to hold statistics of the propagator. More...
class	ProtoAxis
	This class is a pure run-time placeholder for the axis definition. More...
struct	ProtoLayer
	Forward-declaration friendly class for backward compatibility This class does not allow modification of the underlying surfaces. More...
class	ProtoLayerHelper
	This class is designed to parse a vector of Surfaces and sort them into corresponding proto layers. More...
class	ProtoSurfaceMaterialT
	proxy to SurfaceMaterial hand over BinUtility or other suitable binning description More...
class	ProtoVolumeMaterial
	proxy to VolumeMaterial hand over BinUtility More...
struct	ProxyAccessorBase
	Utility class that eases accessing dynamic columns in track and track state containers. More...
class	RadialBounds
	Class to describe the bounds for a planar DiscSurface. More...
class	RangeXD
	An orthogonal range in an arbitrary number of dimensions. More...
class	Ray
	Class which models a ray. More...
struct	RecordedMaterial
	Simple result struct to be returned It mainly acts as an internal state which is created for every propagation/extrapolation step. More...
class	RectangleBounds
struct	RefHolder
	Non-owning holder for referencing a backend. More...
class	RegularSurface
	A physical surface which does not depend on the direction you look at it from. More...
struct	RemovePointer
	Introduce the Acts version of the pointer remove type trait because we want to fetch the underlying type for the pointer concept and std::library does not allow for an extension of the std::remove_pointer;. More...
struct	RemovePointer< T >
	This specialization allows std::remove_pointer to work with types satisfying Acts::SmartPointerConcept, similar to how it works with raw pointers. More...
class	Result
	Class which encapsulates either a valid result, or an error. More...
class	Result< void, E >
	Template specialization for the void case. More...
class	ScopedTimer
	A RAII timer class for measuring execution time of code blocks. More...
class	ScoreBasedAmbiguityResolution
	Generic implementation of the score based ambiguity resolution. More...
struct	SeedConfirmationRangeConfig
	Contains parameters for quality seed confirmation. More...
class	SeedContainer
	A container of seeds. More...
class	SeedProxy
	A proxy class for accessing individual seeds. More...
class	SensorLayer
	Fluent builder that assembles a single cylindrical or disc-like detector layer directly from sensor elements, returning a LayerBlueprintNode (no container wrapper). More...
class	SensorLayerAssembler
	Fluent builder that assembles multiple cylindrical or disc-like detector layers directly from sensor elements into a CylinderContainerBlueprintNode. More...
class	SingleCuboidPortalShell
	This class describes a cuboid shell containing a single volume. More...
class	SingleCylinderPortalShell
	This class describes a cylinder shell containing a single volume. More...
class	SingleDiamondPortalShell
	Implementation of a portal shell class for a single convex polygon volume. More...
class	SingleTrapezoidPortalShell
	This class describes a trapezoid shell containing a single volume. More...
class	SolenoidBField
	Analytical solenoid magnetic field implementation. More...
class	SourceLink
	Type-erased source link wrapper. More...
struct	SourceLinkAdapterIterator
	Iterator adapter returning SourceLink wrappers. More...
class	SpacePointColumnProxy
	Additional column of data that can be added to the space point container. More...
class	SpacePointContainer
	A container for space points, which can hold additional columns of data and allows for efficient access to space points and their associated source links. More...
class	SpacePointProxy
	A proxy class for accessing individual space points. More...
class	StaticBlueprintNode
	The static blueprint node wraps a single already-constructred TrackingVolume. More...
struct	StepperPlainOptions
	Common options shared by plain steppers. More...
struct	StepperStatistics
	A struct to hold statistics of the stepper. More...
class	StraightLineStepper
	straight line stepper based on Surface intersection More...
class	StrawSurface
	Class for a StrawSurface in the TrackingGeometry to describe dirft tube and straw like detectors. More...
struct	SupportsBoundParameters
struct	SupportsBoundParameters< EigenStepper<> >
struct	SupportsBoundParameters< StraightLineStepper >
struct	SupportsBoundParameters< SympyStepper >
class	Surface
	Abstract Base Class for tracking surfaces. More...
class	SurfaceArray
	Provides Surface binning in 2 dimensions. More...
class	SurfaceArrayCreator
	It is designed create sub surface arrays to be ordered on Surfaces. More...
class	SurfaceArrayNavigationPolicy
	A navigation policy that internally uses the Gen1 SurfaceArray class. More...
struct	SurfaceBinningMatcher
	Helper to compare surfaces for binning equivalence. More...
class	SurfaceBounds
	Interface for surface bounds. More...
struct	SurfaceCollector
	A Surface Collector struct templated with a Selector type. More...
struct	SurfaceHit
	The information to be writtern out per hit surface. More...
class	SurfaceJsonConverter
	Static class performing JSON conversion of the surfaces. More...
class	SurfaceMaterialMapper
	SurfaceMaterialMapper. More...
class	SurfaceMergingException
	Exception type failures to merge two surfaces. More...
class	SurfacePlacementBase
	The SurfacePlacementBase is an API proxy to model the dynamic movement of the Acts::Surface representing e.g. More...
struct	SurfaceReached
	This is the condition that the Surface has been reached it then triggers a propagation abort. More...
struct	SurfaceSelector
	Simple struct to select surfaces. More...
class	SympyStepper
	Stepper implementation using sympy-generated expressions. More...
class	Table
	A utility class for creating formatted markdown tables with automatic column sizing and alignment. More...
class	ToroidField
	Toroid magnetic field implementation. More...
class	TrackAtVertex
	Defines a track at vertex object. More...
class	TrackContainer
	Track container interface class. More...
class	TrackDensityVertexFinder
	Finds a vertex seed based on the maximum of a track density function. More...
class	TrackingGeometry
	The TrackingGeometry class is the owner of the constructed TrackingVolumes. More...
class	TrackingGeometryBuilder
	The Acts::TrackingGeometry Builder for volumes that wrap around another. More...
class	TrackingGeometryJsonConverter
	Converter for tracking geometry JSON payloads. More...
class	TrackingGeometryMutableVisitor
	Mutable visitor interface for modifying the tracking geometry hierarchy. More...
class	TrackingGeometryVisitor
	Visitor interface for traversing the tracking geometry hierarchy. More...
class	TrackingVolume
	Full Volume description used in Tracking, it inherits from Volume to get the geometrical structure. More...
class	TrackingVolumeArrayCreator
	The TrackingVolumeArrayCreator is a simple Tool that helps to construct binned arrays of TrackingVolumes for both, confinement in another volume and navigation issues. More...
class	TrackParamsLookupAccumulator
	Class to accumulate and average track lookup tables. More...
class	TrackProxy
	Proxy class representing a single track. More...
class	TrackProxyCommon
	Common CRTP implementation shared by the various track proxy front-ends. More...
class	TrackSelector
	Class which performs filtering of tracks. More...
struct	TrackStateCreator
	Create track states for selected measurements associated to a surface. More...
class	TrackStateProxy
	Proxy object to access a single point on the trajectory. More...
class	TrackStateProxyCommon
	Common CRTP implementation shared by track state proxy front-ends. More...
struct	TrackStateTraits
	Type aliases describing track state component mappings. More...
class	TrackStateType
	TrackStateTypeBase captured by value. More...
class	TrackStateTypeBase
	CRTP base class for TrackStateType and TrackStateTypeMap. More...
class	TrackStateTypeMap
	TrackStateTypeBase mapped to external storage. More...
class	TrapezoidBounds
	Bounds for a trapezoidal, planar Surface. More...
class	TrapezoidPortalShell
	Base class for trapezoid shaped portal shells, e.g. More...
class	TrapezoidVolumeBounds
	Bounds for a trapezoidal shaped Volume, the orientedSurface(...) method creates a vector of 6 surfaces: More...
class	TripletSeeder
	Full triplet seeder which depends on a doublet and triplet seed finder, and a triplet seed filter. More...
class	TripletSeedFinder
	Interface and a collection of standard implementations for a triplet seed finder. More...
class	TripletTopCandidates
	Container for triplet candidates found by the triplet seed finder. More...
class	TrivialPortalLink
	Trivial portal link links to a single target volume on every point on a surface. More...
class	TryAllNavigationPolicy
	Policy which adds all candidates of the configured type to the stream. More...
class	TypeDispatcher
	Template class for type-based function dispatch. More...
class	TypeDispatcher< base_t, return_t(args_t...)>
	Type dispatcher specialization for function signature. More...
struct	TypeList
	type list implementation More...
struct	TypeTag
struct	ValueHolder
	Owning holder that stores a backend by value. More...
class	VariableSubspaceHelper
	Helper class for variable subspace operations. More...
class	VectorMultiTrajectory
	In-memory transient multi-trajectory implementation using std::vector as backend. More...
class	VectorTrackContainer
	Track container backend using std::vector for storage. More...
class	Vertex
	Class for storing vertex objects. More...
struct	VertexInfo
	Helper struct for storing vertex related information. More...
struct	VertexingOptions
	Vertex Finder Options. More...
struct	ViewConfig
	Struct to concentrate all visualization configurations in order to harmonize visualization interfaces. More...
class	VoidNavigator
	A navigator that does nothing. More...
class	Volume
	It inherits from GeometryObject for geometry identification. More...
class	VolumeBounds
	Pure Absract Base Class for Volume bounds. More...
struct	VolumeCollector
	A Volume Collector struct templated with a Selector type. More...
struct	VolumeConfig
	VolumeConfig struct to understand the layer config. More...
struct	VolumeConstraintAborter
	This is the condition that the end of world has been reached it then triggers a propagation abort. More...
struct	VolumeHit
	The information to be writtern out per hit volume. More...
class	VolumeMaterialMapper
	VolumeMaterialMapper. More...
class	VolumePlacementBase
	Interface class to define the transform cache backend for alignable volumes. More...
struct	VolumeSelector
	Simple struct to select volumes. More...
class	VolumeStack
	A stack of volumes. More...
struct	WrappingConfig
	The WrappingSetup that is happening here. More...
class	ZScanVertexFinder
	Implements a vertex finder based on the mode of z0 values: More...

Concepts
concept	Actor
concept	ActorHasAbort
concept	ActorHasAbortWithoutResult
concept	ActorHasAbortWithResult
concept	ActorHasAct
concept	ActorHasActWithoutResult
concept	ActorHasActWithResult
concept	ActorHasOldVoidInterface
concept	ActorHasResult
concept	AmbiguityNetworkConcept
	Concept for the ambiguity network used in the ambiguity resolution.
concept	AxisConcept
concept	BoundTrackParametersConcept
	Concept that asserts that a given type meets the requirements to be considered bound track parameters in Acts.
concept	CommonMultiTrajectoryBackend
concept	ConstMultiTrajectoryBackend
concept	ConstTrackContainerBackend
concept	ConstTrackProxyConcept
concept	ConstTrackStateProxyConcept
concept	FreeTrackParametersConcept
	Concept that asserts that a given type meets the requirements to be considered free track parameters in Acts.
concept	hasPrintOperator
	Define a generic concept whether an object can be piped to an ostream / cout.
concept	HolderFor
	Concept for holder templates that provide pointer-like access.
concept	isValidConvexPolygonSize
concept	MutableMultiTrajectoryBackend
concept	MutableSurfaceVisitor
concept	MutableTrackContainerBackend
concept	MutableTrackProxyConcept
concept	MutableTrackStateProxyConcept
concept	NavigationPolicyConcept
	Concept for a navigation policy This exists so initializeCandidates can be a non-virtual method and we still have a way to enforce it exists.
concept	NavigatorConcept
	Concept that is satisfied by navigators.
concept	PointerConcept
concept	RegularSurfaceConcept
concept	SmartPointerConcept
	The Pointer concept is an extension of the usual std::is_pointer_v type trait to also include the smart pointers like std::shared_ptr<T>, std::unique_ptr<T> The smart pointer is required to have an element_type typedef indicating over which data type the pointer is constructed, the arrow operator.
concept	StepperConcept
	Concept that is satisfied by steppers.
concept	StepperStateConcept
	Concept that is satisfied by stepper states.
concept	SurfaceConcept
concept	SurfaceVisitor
concept	TrackContainerBackend
concept	TrackContainerFrontend
concept	TrackingVolumeVisitor
concept	TrackProxyConcept
concept	TrackStateProxyConcept

Typedefs
using	AlignmentMatrix = Matrix<eAlignmentSize, eAlignmentSize>
	Square matrix type for alignment parameters.
using	AlignmentRowVector = Matrix<1, eAlignmentSize>
	Row vector type for alignment parameters.
using	AlignmentToBoundMatrix = Matrix<eBoundSize, eAlignmentSize>
	Matrix type for transforming alignment parameters to bound parameters.
using	AlignmentToPathMatrix = Matrix<1, eAlignmentSize>
	Matrix type for transforming alignment parameters to path length.
using	AlignmentToPositionMatrix = Matrix<3, eAlignmentSize>
	Matrix type for transforming alignment parameters to position.
using	AlignmentVector = Vector<eAlignmentSize>
	Vector type for alignment parameters.
using	AngleAxis3 = Eigen::AngleAxis<double>
	Rotation defined by an angle around a rotation axis in 3D.
using	Any = AnyBase<sizeof(void*), true>
	A type-safe container for single values of any type.
using	AnyConstTrackProxy = AnyTrackProxy<true>
	Alias for read-only type-erased track.
using	AnyConstTrackStateProxy = AnyTrackStateProxy<true>
	Type alias for a const track state proxy.
using	AnyMoveOnly = AnyBase<sizeof(void*), false>
	Move-only variant that can store move-only types (e.g.
using	AnyMutableTrackProxy = AnyTrackProxy<false>
	Alias for mutable type-erased track (though currently all operations are const).
using	AnyMutableTrackStateProxy = AnyTrackStateProxy<false>
	Type alias for a mutable track state proxy.
template<typename Base, std::size_t SbSize = sizeof(void*)>
using	AnyOf = AnyBase<SbSize, true, Base>
	Typed type-erased value over a common polymorphic base.
using	AtlasBetheHeitlerApprox = PolynomialBetheHeitlerApprox
using	BoundarySurface = BoundarySurfaceT<TrackingVolume>
	Type alias for boundary surface with TrackingVolume.
using	BoundMatrix = Matrix<eBoundSize, eBoundSize>
	Matrix type for bound track parameter transformations.
using	BoundSubspaceIndices = SubspaceIndices<eBoundSize>
	Type alias for bound parameter subspace indices.
using	BoundToFreeMatrix = Matrix<eFreeSize, eBoundSize>
	Matrix type for mapping from bound to free track parameters.
using	BoundVector = Vector<eBoundSize>
	Vector type for bound track parameters.
using	ConfigPair
	Type alias for a pair of detector configuration and ambiguity resolution configuration.
template<bool C, typename T>
using	const_if_t = std::conditional_t<C, const T, T>
	Type trait that adds const qualifier to a type based on a boolean condition.
template<PointerConcept T>
using	ConstDeRef_t = std::add_const_t<RemovePointer_t<T>>&
	Construct a const pointer dereference.
template<typename T>
using	ConstProxyAccessor = ProxyAccessorBase<T, true>
	Type alias for a const proxy accessor.
using	ConstSeedProxy = SeedProxy<true>
	Const proxy to a seed for read-only access.
template<typename T>
using	ConstSpacePointColumnProxy = SpacePointColumnProxy<T, true>
	Const proxy to a space point column for read-only access.
using	ConstSpacePointProxy = SpacePointProxy<true>
	Const proxy to a space point for read-only access.
using	ConstTrackStateTypeMap = TrackStateTypeMap<true>
	Const track state type map for read-only access.
using	DetectorConfig = ScoreBasedAmbiguityResolution::DetectorConfig
	Type alias for detector-specific ambiguity resolution configuration.
using	DynamicMatrix = Eigen::Matrix<double, Eigen::Dynamic, Eigen::Dynamic>
	Dynamic-sized matrix type.
using	DynamicVector = Eigen::Matrix<double, Eigen::Dynamic, 1>
	Dynamic-sized vector type.
using	EAxis = Acts::Axis<AxisType::Equidistant>
	Type alias for equidistant axis with open boundary type.
using	Envelope = std::array<double, 2>
	Type alias for envelope values in different directions.
template<std::size_t SubspaceSize>
using	FixedBoundSubspaceHelper
	Helper type for fixed-size bound parameter subspaces.
using	FreeMatrix = Matrix<eFreeSize, eFreeSize>
	Matrix type for free track parameter transformations.
using	FreeToBoundMatrix = Matrix<eBoundSize, eFreeSize>
	Matrix type for mapping from free to bound track parameters.
using	FreeToPathMatrix = Matrix<1, eFreeSize>
	Matrix type for mapping from free parameters to path length.
using	FreeVector = Vector<eFreeSize>
	Vector type for free track parameters.
template<typename grid_type>
using	GloballyIndexedSurfaceMaterial
	Type alias for surface material indexed by global coordinates.
using	Grid2D = Acts::Grid<Acts::AccumulatedVolumeMaterial, EAxis, EAxis>
	Type alias for a 2-dimensional grid.
using	Grid3D = Acts::Grid<Acts::AccumulatedVolumeMaterial, EAxis, EAxis, EAxis>
	Type alias for a 3-dimensional grid.
template<typename grid_type>
using	GridSurfaceMaterial
	Type alias for grid-based surface material.
using	HashedString = std::uint32_t
	Type alias for hashed string representation.
using	IMultiAxis1D = IMultiAxisXD<1>
	Type alias for a multi-axis of dimension 1.
using	IMultiAxis2D = IMultiAxisXD<2>
	Type alias for a multi-axis of dimension 2.
using	IMultiAxis3D = IMultiAxisXD<3>
	Type alias for a multi-axis of dimension 3.
template<typename grid_type>
using	IndexedSurfaceMaterial
	Type alias for surface material indexed by local coordinates.
using	Intersection2D = Intersection<2>
	Type alias for 2D intersection.
using	Intersection3D = Intersection<3>
	Type alias for 3D intersection.
using	IntersectionIndex = std::uint8_t
	Index type for intersections.
using	LayerPtr = std::shared_ptr<const Layer>
	A std::shared_ptr to a Layer.
using	MaterialGrid2D
	Type alias for a 2-dimensional material grid.
using	MaterialGrid3D
	Type alias for a 3-dimensional material grid.
using	MaterialGridAxisData = std::tuple<double, double, std::size_t>
	Type alias for the axis data in material grids.
using	MaterialSlabMatrix = std::vector<MaterialSlabVector>
	Type alias for a matrix of material slabs.
using	MaterialSlabVector = std::vector<MaterialSlab>
	Type alias for a vector of material slabs.
template<unsigned int kRows, unsigned int kCols>
using	Matrix = Eigen::Matrix<double, kRows, kCols>
	Fixed-size matrix type for NxM matrices.
using	MaxMomentumReducerLoop
	Type alias for loop reducer based on maximum momentum.
using	MaxWeightReducerLoop
	Type alias for loop reducer based on maximum weight.
template<typename extension_t = EigenStepperDefaultExtension, typename reducer_t = MaxWeightReducerLoop>
using	MultiEigenStepperLoop
	Stepper based on the EigenStepper, but handles Multi-Component Tracks (e.g., for the GSF).
using	MultiIntersection2D = MultiIntersection<2>
	Container for up to two 2D intersections.
using	MultiIntersection3D = MultiIntersection<3>
	Container for up to two 3D intersections.
using	MutableLayerPtr = std::shared_ptr<Layer>
	Type alias for a mutable pointer to a layer.
using	MutableSeedProxy = SeedProxy<false>
	Mutable proxy to a seed allowing modification.
template<typename T>
using	MutableSpacePointColumnProxy = SpacePointColumnProxy<T, false>
	Mutable proxy to a space point column allowing modification.
using	MutableSpacePointProxy = SpacePointProxy<false>
	Mutable proxy to a space point allowing modification.
using	MutableTrackStateTypeMap = TrackStateTypeMap<false>
	Mutable track state type map allowing modification.
using	NavigationDelegate
	Central alias for the navigation delegate.
using	NavigationPolicyStateStorage = AnyBase<kNavigationPolicyStateSbo>
	Type-erased storage for a single navigation policy state, with small-buffer optimization so the common (small) states avoid heap allocation.
using	NextLayers = std::pair<const Layer*, const Layer*>
	Type alias for adjacent layer pointers.
using	ProjectorBitset = std::uint64_t
	Type alias for bitset representing parameter projections.
using	ProtoGridSurfaceMaterial
	Type alias for a prototype surface material using a grid of ProtoAxis A surface material implementation that uses a vector of ProtoAxis for grid-based binning.
using	ProtoSurfaceMaterial = ProtoSurfaceMaterialT<Acts::BinUtility>
	Type alias for a prototype surface material using BinUtility A surface material implementation that uses BinUtility for binning.
template<typename T>
using	ProxyAccessor = ProxyAccessorBase<T, false>
	Type alias for a mutable proxy accessor.
template<typename Type, template< typename, std::size_t > typename Vector = std::array>
using	Range1D = RangeXD<1, Type, Vector>
	Type alias for a one-dimensional range.
using	Ray3D = Ray<double, 3>
	Type alias for a 3D ray using double precision.
using	RecordedMaterialTrack
	And recorded material track.
using	RecordedMaterialVolumePoint
	list of point used in the mapping of a volume
using	RegularCylinderIndexGrid
	Regular cylinder grid in phi and z.
using	RegularCylinderIndexGridNavigationPolicy
	Navigation policy for regular cylinder grids.
using	RegularDiscIndexGrid
	Regular disc grid in r and phi.
using	RegularDiscIndexGridNavigationPolicy
	Navigation policy for regular disc grids.
using	RegularPlaneIndexGrid
	Regular planar grid in x and y.
using	RegularPlaneIndexGridNavigationPolicy
	Navigation policy for regular planar grids.
using	RegularRingIndexGrid
	Regular ring grid in phi.
using	RegularRingIndexGridNavigationPolicy
	Navigation policy for regular ring grids.
template<typename T>
using	RemovePointer_t = RemovePointer<T>::type
	Helper type alias for removing pointer from type.
using	RotationMatrix2 = SquareMatrix2
	2D rotation matrix
using	RotationMatrix3 = SquareMatrix3
	3D rotation matrix
using	SeedIndex = std::uint32_t
	Index type for seeds.
using	SerializedSubspaceIndices = std::uint64_t
	Type alias for serialized subspace indices.
using	SourceLinkSurfaceAccessor = Delegate<const Surface*(const SourceLink&)>
	Delegate to unpack the surface associated with a source link.
using	SpacePointIndex = std::uint32_t
	Index type for space points.
using	SpacePointIndexRange = std::pair<SpacePointIndex, SpacePointIndex>
	Range of space point indices defined by a pair of start and end indices.
using	SpacePointIndexSubset = std::span<const SpacePointIndex>
	Subset of space point indices represented as a span.
template<unsigned int kSize>
using	SquareMatrix = Eigen::Matrix<double, kSize, kSize>
	Fixed-size square matrix type for NxN matrices.
using	SquareMatrix2 = SquareMatrix<2>
	2x2 square matrix type, typically used for 2D coordinate covariance
using	SquareMatrix3 = SquareMatrix<3>
	3x3 square matrix type, typically used for 3D coordinate covariance
using	SquareMatrix4 = SquareMatrix<4>
	4x4 square matrix type, typically used for 4D coordinate covariance
using	SubspaceIndex = std::uint8_t
	Type alias for subspace index.
template<std::size_t measdim>
using	SubspaceIndices = std::array<SubspaceIndex, measdim>
	Template alias for subspace indices array.
using	SurfaceAndMaterialWithContext
	A tuple containing a surface, its associated material, and geometry context.
using	SurfaceBoundFactory = BoundFactory<const SurfaceBounds>
	Abrivation for a factory to construct surface bounds.
using	SurfaceMatcher
	Function type for comparing two surfaces in a given geometry context and axis direction.
using	SurfaceMaterialMaps
	Type alias for surface material maps indexed by geometry identifier.
using	surfaceMaterialPointer = const Acts::ISurfaceMaterial*
	Pointer to a constant surface material object.
using	SurfaceMatrix = std::vector<SurfaceVector>
	Matrix (2D vector) of pointers to constant Surface objects.
using	SurfaceVector = std::vector<const Surface*>
	Vector of pointers to constant Surface objects.
using	TrackIndexType = std::uint32_t
	Type alias for track index values.
using	TrackingGeometryMaterial
	Type alias for tracking geometry material containing surface and volume maps.
using	TrackingVolumeAndMaterial
	A pair containing a tracking volume and its associated material.
using	TrackingVolumeOrderPosition = std::pair<TrackingVolumePtr, Vector3>
	A pair associating a tracking volume with its position vector.
using	TrackLinearizer
	A delegate for linearizing a track at a given point in time and surface.
using	Transform2 = Eigen::Transform<double, 2, Eigen::AffineCompact>
	2D affine transformation stored as a compact 2x3 matrix
using	Transform3 = Eigen::Transform<double, 3, Eigen::Affine>
	3D affine transformation stored as a 4x4 matrix
using	Translation2 = Eigen::Translation<double, 2>
	2D translation transformation
using	Translation3 = Eigen::Translation<double, 3>
	3D translation transformation
using	V3Matrix = std::vector<V3Vector>
	Matrix (2D vector) of 3D vectors, used for storing grid-like collections of 3D points.
using	V3Vector = std::vector<Vector3>
	Vector of 3D vectors, used for storing collections of 3D points.
using	VariableBoundSubspaceHelper
	Helper type for variable-size bound parameter subspaces.
template<unsigned int kSize>
using	Vector = Eigen::Matrix<double, kSize, 1>
	Fixed-size vector type for N-dimensional vectors.
using	Vector2 = Vector<2>
	2-dimensional vector type for 2D coordinates
using	Vector3 = Vector<3>
	3-dimensional vector type for e.g. spatial coordinates and momenta
using	Vector4 = Vector<4>
	4-dimensional vector type for space-time coordinates
using	VolumeBoundFactory = BoundFactory<VolumeBounds>
	Abrivation for a factory to construct volume bounds.
using	VolumeMaterialMaps
	Type alias for volume material maps indexed by geometry identifier.
using	volumeMaterialPointer = const Acts::IVolumeMaterial*
	Pointer to a constant volume material object.
using	TrackingVolumePtr = std::shared_ptr<const TrackingVolume>
	A std::shared_ptr to a tracking volume.
using	TrackingVolumeArray = BinnedArray<TrackingVolumePtr>
	A BinnedArray of a std::shared_tr to a TrackingVolume.
using	MutableTrackingVolumePtr = std::shared_ptr<TrackingVolume>
	Shared pointer to a mutable TrackingVolume.
using	MutableTrackingVolumeVector = std::vector<MutableTrackingVolumePtr>
	Vector of shared pointers to mutable TrackingVolumes.
using	LayerArray = BinnedArray<LayerPtr>
	A BinnedArray to a std::shared_ptr of a layer.
using	LayerVector = std::vector<LayerPtr>
	A vector of std::shared_ptr to layers.
using	TrackingVolumeVector = std::vector<TrackingVolumePtr>
	A std::vector of a std::shared_ptr to a TrackingVolume.
using	TrackingVolumeBoundaryPtr
	Shared pointer to a constant BoundarySurfaceT of a TrackingVolume.
using	TrackingVolumeBoundaries = std::vector<TrackingVolumeBoundaryPtr>
	Type alias for collection of tracking volume boundaries.

Enumerations
enum	AlignmentIndices : unsigned int {   eAlignmentCenter0 = 0u , eAlignmentCenter1 = eAlignmentCenter0 + 1u , eAlignmentCenter2 = eAlignmentCenter0 + 2u , eAlignmentRotation0 = 3u ,   eAlignmentRotation1 = eAlignmentRotation0 + 1u , eAlignmentRotation2 = eAlignmentRotation0 + 2u , eAlignmentSize }
	Components of alignment parameters vector. More...
enum class	AxisBoundaryType { Open , Bound , Closed }
	Enum which determines how the axis handle its outer boundaries possible values values. More...
enum class	AxisDirection : int {   AxisX = 0 , AxisY = 1 , AxisZ = 2 , AxisR = 3 ,   AxisPhi = 4 , AxisRPhi = 5 , AxisTheta = 6 , AxisEta = 7 ,   AxisMag = 8 }
	to specify a local axis direction More...
enum class	AxisType { Equidistant , Variable }
	Enum which determines the binning type of the axis. More...
enum	BinningOption { open , closed }
	flag for open/closed bins
enum	BinningType { equidistant , arbitrary }
	, BinningOption & BinningAccess More...
enum	BoundarySurfaceFace {   negativeFaceXY = 0 , positiveFaceXY = 1 , negativeFaceYZ = 2 , positiveFaceYZ = 3 ,   negativeFaceZX = 4 , positiveFaceZX = 5 , cylinderCover = 2 , tubeInnerCover = 3 ,   tubeOuterCover = 2 , tubeSectorNegativePhi = 4 , tubeSectorPositivePhi = 5 , tubeSectorInnerCover = 3 ,   tubeSectorOuterCover = 2 , trapezoidFaceAlpha = 2 , trapezoidFaceBeta = 3 , index0 = 0 ,   index1 = 1 , index2 = 2 , index3 = 3 , index4 = 4 ,   index5 = 5 , index6 = 6 , index7 = 7 , index8 = 8 ,   index9 = 9 , index10 = 10 , index11 = 11 , undefinedFace = 99 }
	Enum to describe the position of the BoundarySurface respectively to the frame orientation of the volume, this is mainly meant for code readability. More...
enum	BoundIndices : unsigned int {   eBoundLoc0 = 0 , eBoundLoc1 = 1 , eBoundPhi = 2 , eBoundTheta = 3 ,   eBoundQOverP = 4 , eBoundTime = 5 , eBoundSize }
	Components of a bound track parameters vector. More...
enum class	CombinatorialKalmanFilterBranchStopperResult { Continue , StopAndDrop , StopAndKeep }
	Return type of the BranchStopper delegate for the CombinatorialKalmanFilter.
enum class	CombinatorialKalmanFilterError {   CombinatorialKalmanFilterError::UpdateFailed = 1 , CombinatorialKalmanFilterError::SmoothFailed , CombinatorialKalmanFilterError::OutputConversionFailed , CombinatorialKalmanFilterError::MeasurementSelectionFailed ,   CombinatorialKalmanFilterError::PropagationReachesMaxSteps , CombinatorialKalmanFilterError::NoMeasurementExpected }
	Error codes for combinatorial Kalman filter operations. More...
enum class	ComponentMergeMethod { eMean , eMaxWeight }
	Available reduction methods for the reduction of a Gaussian mixture.
enum	CoordinateIndices : unsigned int {   ePos0 = 0 , ePos1 = 1 , ePos2 = 2 , eTime = 3 ,   eMom0 = ePos0 , eMom1 = ePos1 , eMom2 = ePos2 , eEnergy = eTime ,   eX = ePos0 , eY = ePos1 , eZ = ePos2 }
	Components of coordinate vectors. More...
enum class	DelegateType { Owning , NonOwning }
	Ownership enum for Delegate.
enum class	EigenStepperError { EigenStepperError::StepSizeStalled = 1 , EigenStepperError::StepInvalid , EigenStepperError::StepSizeAdjustmentFailed }
	Error codes for Eigen stepper operations. More...
enum	FreeIndices : unsigned int {   eFreePos0 = 0u , eFreePos1 = eFreePos0 + 1u , eFreePos2 = eFreePos0 + 2u , eFreeTime = 3u ,   eFreeDir0 = 4u , eFreeDir1 = eFreeDir0 + 1u , eFreeDir2 = eFreeDir0 + 2u , eFreeQOverP = 7u ,   eFreeSize }
	Components of a free track parameters vector. More...
enum class	GsfError { GsfError::StartParametersHaveNoCovariance , GsfError::NoMeasurementStatesCreatedForward , GsfError::NoMeasurementStatesCreatedBackward , GsfError::NoMeasurementStatesCreatedFinal }
	Error codes for Gaussian Sum Filter operations. More...
enum class	HadronType {   Hadron = 1 , BBbarMeson = 2 , CCbarMeson = 3 , BottomMeson = 4 ,   BottomBaryon = 5 , CharmedMeson = 6 , CharmedBaryon = 7 , StrangeMeson = 8 ,   StrangeBaryon = 9 , LightMeson = 10 , LightBaryon = 11 , Unknown = 12 }
	Hadron type classification for B, C, strange and light hadrons.
enum class	IntersectionStatus : int { unreachable = 0 , reachable = 1 , onSurface = 2 }
	Status enum.
enum class	KalmanFitterError {   KalmanFitterError::UpdateFailed = 1 , KalmanFitterError::SmoothFailed , KalmanFitterError::OutputConversionFailed , KalmanFitterError::NoMeasurementFound ,   KalmanFitterError::ReversePropagationFailed , InconsistentTrackStates }
	Error codes for Kalman filter operations. More...
enum	LayerType { navigation = -1 , passive = 0 , active = 1 }
	For code readability, it distinguishes between different type of layers, which steers the behaviour in the navigation.
enum	LinIndices : unsigned int {   eLinPos0 = 0u , eLinPos1 = eLinPos0 + 1u , eLinPos2 = eLinPos0 + 2u , eLinTime = 3u ,   eLinPhi = 4u , eLinTheta = eLinPhi + 1u , eLinQOverP = 6u , eLinSize = 7u ,   eLinPosSize = 4u , eLinMomSize = 3u }
	Enum to access the components of a track parameter vector. More...
enum class	MagneticFieldError { MagneticFieldError::OutOfBounds = 1 , MagneticFieldError::NotImplemented = 2 }
	Error codes for magnetic field operations. More...
enum class	MappingType : std::int8_t { PreMapping = -1 , Default = 0 , PostMapping = 1 , Sensor = 2 }
	This enum describes the type of surface material mapping.
enum class	MaterialUpdateMode : std::uint8_t { NoUpdate = 0 , PreUpdate = 1 , PostUpdate = 2 , FullUpdate = PreUpdate | PostUpdate }
	This is a steering enum to tell which material update mode: More...
enum class	MultiStepperError {   MultiStepperError::ComponentNotOnSurface = 1 , MultiStepperError::StateOfMultipleComponentsRequested = 2 , MultiStepperError::AverageTrackLeftCurrentVolume = 3 , MultiStepperError::AllComponentsSteppingError = 4 ,   MultiStepperError::AllComponentsConversionToBoundFailed = 5 , MultiStepperError::SomeComponentsConversionToBoundFailed = 6 }
	Error codes for multi-stepper operations. More...
enum class	NavigatorError { NavigatorError::NotInsideExpectedVolume = 1 , NavigatorError::NotOnExpectedSurface = 2 , NavigatorError::NoStartVolume = 3 }
	Error codes for navigator operations. More...
enum class	NoiseUpdateMode : int { removeNoise = -1 , addNoise = 1 }
	Steering enum to tell how to deal with the noise term in covariance transport: More...
enum	PdgParticle : std::int32_t {   eInvalid = 0 , eElectron = 11 , eAntiElectron = -eElectron , ePositron = -eElectron ,   eMuon = 13 , eAntiMuon = -eMuon , eTau = 15 , eAntiTau = -eTau ,   eGamma = 22 , ePionZero = 111 , ePionPlus = 211 , ePionMinus = -ePionPlus ,   eKaonPlus = 321 , eKaonMinus = -eKaonPlus , eNeutron = 2112 , eAntiNeutron = -eNeutron ,   eProton = 2212 , eAntiProton = -eProton , eLead = 1000822080 , eKaon0Short = 310 ,   eLambda0 = 3122 , eJPsi = 443 , eB0 = 511 , eBPlus = 521 ,   eD0 = 421 , eDPlus = 411 , eAntiB0 = -eB0 , eAntiD0 = -eD0 ,   eNeutrinoE = 12 , eNeutrinoMu = 14 , eNeutrinoTau = 16 , eAntiNeutrinoE = -eNeutrinoE ,   eAntiNeutrinoMu = -eNeutrinoMu , eAntiNeutrinoTau = -eNeutrinoTau }
	Symbolic values for commonly used PDG particle numbers.
enum class	PortalError { PortalError::PositionNotOnAnyChildPortalLink = 1 }
	Error codes for portal operations. More...
enum class	PortalMaterialMergePolicy { eThrow , eDiscardAndMark }
	Policy controlling how Acts::Portal::merge treats surfaces that carry material. More...
enum class	PropagatorError { PropagatorError::Failure = 1 , PropagatorError::StepCountLimitReached , PropagatorError::NextTargetLimitReached }
	Error codes for propagator operations. More...
enum class	PropagatorStage {   invalid , prePropagation , postPropagation , preStep ,   postStep }
	Different stages during propagation. More...
enum class	SeedColumns : std::uint32_t {   None = 0 , SpacePointIndices , Quality = 1 << 1 , VertexZ = 1 << 2 ,   All = SpacePointIndices | Quality | VertexZ }
	Enumeration of available columns for space point data storage. More...
enum class	SpacePointColumns : std::uint32_t {   None = 0 , SourceLinks = 1 << 0 , CopiedFromIndex = 1 << 1 , X = 1 << 2 ,   Y = 1 << 3 , Z = 1 << 4 , R = 1 << 5 , Phi = 1 << 6 ,   Time = 1 << 7 , VarianceZ = 1 << 8 , VarianceR = 1 << 9 , VarianceT = 1 << 10 ,   StripCalibrationDetails = 1 << 11 , PackedXY = 1 << 12 , PackedZR = 1 << 13 , PackedXYZ = 1 << 14 ,   PackedXYZR = 1 << 15 , PackedVarianceZR = 1 << 16 , All }
	Enumeration of available columns for space point data storage. More...
enum class	SpacePointFormationError {   SpacePointFormationError::ClusterPairDistanceExceeded = 1 , SpacePointFormationError::ClusterPairThetaDistanceExceeded = 2 , SpacePointFormationError::ClusterPairPhiDistanceExceeded = 3 , SpacePointFormationError::CosmicToleranceNotMet = 4 ,   SpacePointFormationError::OutsideLimits = 5 , SpacePointFormationError::OutsideRelaxedLimits = 6 , SpacePointFormationError::NoSolutionFound = 7 }
	Error codes for space point formation operations. More...
enum class	SurfaceError { SurfaceError::GlobalPositionNotOnSurface = 1 }
	Error codes for surface operations. More...
enum class	TrackExtrapolationError { TrackExtrapolationError::CompatibleTrackStateNotFound = 1 , TrackExtrapolationError::ReferenceSurfaceUnreachable = 2 }
	Error codes for track extrapolation operations. More...
enum class	TrackExtrapolationStrategy { first , last , firstOrLast }
	Strategy for track extrapolation to target surface. More...
enum class	TrackStateFlag {   HasMeasurement = 0 , HasParameters = 1 , IsOutlier = 2 , IsHole = 3 ,   HasMaterial = 4 , IsSharedHit = 5 , IsSplitHit = 6 , HasNoExpectedHit = 7 ,   NumFlags = 8 }
	Enumeration of track state flags. More...
enum struct	TrackStatePropMask : std::uint8_t {   None = 0 , Predicted = 1 << 0 , Filtered = 1 << 1 , Smoothed = 1 << 2 ,   Jacobian = 1 << 3 , Calibrated = 1 << 4 , All = std::numeric_limits<std::uint8_t>::max() }
	Collection of bit masks to enable steering which components of a track state should be initialized, and which should be left invalid. More...
enum class	VertexingError {   VertexingError::NumericFailure = 1 , VertexingError::EmptyInput , VertexingError::SeedingError , VertexingError::NotConverged ,   VertexingError::ElementNotFound , VertexingError::NoCovariance , VertexingError::SingularMatrix , VertexingError::NonPositiveVariance ,   VertexingError::MatrixNotPositiveDefinite , VertexingError::InvalidInput , VertexingError::CouldNotRemoveTrack }
	Error codes for vertexing operations. More...
enum class	VolumeAttachmentStrategy { First , Second , Midpoint , Gap }
	The attachment strategy defines how the volumes are attached Attachment always happens pair-wise. More...
enum class	VolumeResizeStrategy { Expand , Gap }
	The resize strategy defines how the volumes are resized. More...
enum	WrappingCondition {   Undefined = 0 , Attaching = 1 , Inserting = 2 , Wrapping = 3 ,   CentralInserting = 4 , CentralWrapping = 5 , NoWrapping = 6 }
	Volume wrapping conditions for cylinder volume building. More...

Functions
template<typename T>
constexpr T	abs (const T n)
	Returns the absolute of a number.
	ACTS_DEFINE_ENUM_BITWISE_OPERATORS (MaterialUpdateMode)
	Enable bitwise operators for MaterialUpdateMode enum.
	ACTS_DEFINE_ENUM_BITWISE_OPERATORS (SeedColumns)
	Enable bitwise operators for SeedColumns enum.
	ACTS_DEFINE_ENUM_BITWISE_OPERATORS (SpacePointColumns)
	Enable bitwise operators for SpacePointColumns enum.
BoundVector	addBoundParameters (const BoundVector &lhs, const BoundVector &rhs)
	Add bound parameters and take care of angle periodicity for phi and theta.
BinUtility	adjustBinUtility (const BinUtility &bu, const CuboidVolumeBounds &cBounds, const Transform3 &transform)
	adjust the BinUtility bu to the dimensions of cuboid volume bounds
BinUtility	adjustBinUtility (const BinUtility &bu, const CutoutCylinderVolumeBounds &cBounds, const Transform3 &transform)
	adjust the BinUtility bu to the dimensions of cutout cylinder volume bounds
static BinUtility	adjustBinUtility (const BinUtility &bu, const CylinderBounds &cBounds, const Transform3 &transform)
	adjust the BinUtility bu to the dimensions of cylinder bounds
BinUtility	adjustBinUtility (const BinUtility &bu, const CylinderVolumeBounds &cBounds, const Transform3 &transform)
	adjust the BinUtility bu to the dimensions of cylinder volume bounds
static BinUtility	adjustBinUtility (const BinUtility &bu, const RadialBounds &rBounds, const Transform3 &transform)
	adjust the BinUtility bu to the dimensions of radial bounds
static BinUtility	adjustBinUtility (const BinUtility &bu, const RectangleBounds &pBounds, const Transform3 &transform)
	adjust the BinUtility bu to the dimensions of plane bounds
static BinUtility	adjustBinUtility (const BinUtility &bu, const Surface &surface, const GeometryContext &gctx)
	adjust the BinUtility bu to a surface
static BinUtility	adjustBinUtility (const BinUtility &bu, const TrapezoidBounds &pBounds, const Transform3 &transform)
	adjust the BinUtility bu to the dimensions of plane bounds
BinUtility	adjustBinUtility (const GeometryContext &gctx, const BinUtility &bu, const Volume &volume)
	adjust the BinUtility bu to a volume
const std::vector< AxisDirection > &	allAxisDirections ()
	Get all possible axis directions.
template<typename T, typename... Axes>
	AnyGridConstView (const Grid< T, Axes... > &grid) -> AnyGridConstView< T >
	Deduction guide for AnyGridConstView from const Grid.
template<typename T, typename... Axes>
	AnyGridView (Grid< T, Axes... > &grid) -> AnyGridView< T >
	Deduction guide for AnyGridView from Grid.
template<typename grid_type>
void	applyReferenceExpansion (std::vector< typename grid_type::point_t > &gridQueries, const std::vector< double > &referenceExpansion)
	Run the reference expansion.
float	approximateHighlandScattering (float xOverX0)
	Approximate the core width of the projected planar scattering distribution with Highland's formula.
std::string	axesDirectionName (const std::vector< AxisDirection > &manyDir)
	Get the name of a vector of binning values as a string.
template<AxisBoundaryType bdt>
	Axis (AxisBoundaryTypeTag< bdt >, double min, double max, std::size_t bins) -> Axis< AxisType::Equidistant, bdt >
	Deduction guide for equidistant axis with specified boundary type.
template<AxisBoundaryType bdt>
	Axis (AxisBoundaryTypeTag< bdt >, std::vector< double > bins) -> Axis< AxisType::Variable, bdt >
	Deduction guide for variable axis with specified boundary type.
	Axis (double min, double max, std::size_t bins) -> Axis< AxisType::Equidistant, AxisBoundaryType::Open >
	Deduction guide for equidistant axis with open boundaries.
	Axis (std::vector< double > bins) -> Axis< AxisType::Variable, AxisBoundaryType::Open >
	Deduction guide for variable axis with open boundaries.
AxisDirection	axisDirectionFromName (const std::string &name)
	Get an axis direction from its string name.
const std::string &	axisDirectionName (AxisDirection aDir)
	Get the name of a binning value as a string.
template<std::unsigned_integral T>
constexpr T	binomial (const T n, const T k)
	Calculate the binomial coefficient n n!
std::vector< std::size_t >	binSequence (std::array< std::size_t, 2u > minMaxBins, std::size_t expand, std::size_t nBins, Acts::AxisBoundaryType type)
	Helper method to generate completely populated bin sequences that respect the boundary type of the axis.
template<typename MatrixType>
MatrixType	bitsetToMatrix (const std::bitset< MatrixType::RowsAtCompileTime *MatrixType::ColsAtCompileTime > bs)
	Convert a bitset to a matrix of integers, with each element set to the bit value.
template<typename A, typename B>
Matrix< A::RowsAtCompileTime, B::ColsAtCompileTime >	blockedMult (const A &a, const B &b)
	Perform a blocked matrix multiplication, avoiding Eigen GEMM methods.
template<TrackStateProxyConcept track_state_proxy_t>
double	calculateFilteredChi2 (track_state_proxy_t trackState)
	Helper function to calculate the filtered chi2.
template<std::size_t nMeasurementDim, TrackStateProxyConcept track_state_proxy_t>
std::pair< Vector< nMeasurementDim >, SquareMatrix< nMeasurementDim > >	calculateFilteredResidual (track_state_proxy_t trackState)
	Helper function to calculate the filtered residual and its covariance.
float	calculateNucleusMass (PdgParticle pdg)
	Calculate the mass of a nucleus using Bethe-Weizsacker formula Parameters obtained from https://www.actaphys.uj.edu.pl/index_n.php?I=R&V=37&N=6#1833.
template<TrackStateProxyConcept track_state_proxy_t>
double	calculatePredictedChi2 (track_state_proxy_t trackState)
	Helper function to calculate the predicted chi2.
template<std::size_t nMeasurementDim, TrackStateProxyConcept track_state_proxy_t>
std::pair< Vector< nMeasurementDim >, SquareMatrix< nMeasurementDim > >	calculatePredictedResidual (track_state_proxy_t trackState)
	Helper function to calculate the predicted residual and its covariance.
template<TrackStateProxyConcept track_state_proxy_t>
double	calculateSmoothedChi2 (track_state_proxy_t trackState)
	Helper function to calculate the smoothed chi2.
template<std::size_t nMeasurementDim, TrackStateProxyConcept track_state_proxy_t>
std::pair< Vector< nMeasurementDim >, SquareMatrix< nMeasurementDim > >	calculateSmoothedResidual (track_state_proxy_t trackState)
	Helper function to calculate the smoothed residual and its covariance.
template<TrackProxyConcept track_proxy_t> requires (!track_proxy_t::ReadOnly)
void	calculateTrackQuantities (track_proxy_t track)
	Helper function to calculate a number of track level quantities and store them on the track itself.
std::pair< BoundVector, BoundMatrix >	calculateUnbiasedParametersCovariance (const AnyConstTrackStateProxy &trackState)
	Calculate the unbiased track parameters and their covariance for a type-erased track state proxy.
template<TrackStateProxyConcept track_state_proxy_t>
std::pair< BoundVector, BoundMatrix >	calculateUnbiasedParametersCovariance (track_state_proxy_t trackState)
	Helper function to calculate the unbiased track parameters and their covariance (i.e.
Eigen::Vector3f	calibrateOuterStripSpacePoint (const Eigen::Vector3f &direction, const OuterStripSpacePointCalibrationDetailsDerived &sp)
	Calibrates the strip space point using the assumed particle direction and the strip space point calibration details.
template<typename T, typename... Args>
constexpr auto	cathetusSquare (T hypotenuse, Args... args)
	Calculates the squared cathetus of arguments, i.e.
template<typename T, typename... Args>
constexpr auto	cathetusSquareUnchecked (T hypotenuse, Args... args)
	Calculates the squared cathetus of arguments, i.e.
template<std::ranges::sized_range index_range_t>
static bool	checkSubspaceIndices (const index_range_t &indexRange, std::size_t fullSize, std::size_t subspaceSize)
	Check subspace indices for consistency.
template<typename T, typename U>
T	clampValue (U value)
	Clamp a numeric value to another type, respecting range of the target type.
template<typename... Fs>
auto	compose (Fs &&... fs)
	Compose multiple callables into a single callable, applied right-to-left (mathematical convention).
float	computeEnergyLossBethe (const MaterialSlab &slab, float m, float qOverP, float absQ)
	Compute the mean energy loss due to ionisation and excitation.
float	computeEnergyLossLandau (const MaterialSlab &slab, float m, float qOverP, float absQ)
	Compute the most probable energy loss due to ionisation and excitation.
float	computeEnergyLossLandauFwhm (const MaterialSlab &slab, float m, float qOverP, float absQ)
	Compute the full with half maximum of landau energy loss distribution.
float	computeEnergyLossLandauSigma (const MaterialSlab &slab, float m, float qOverP, float absQ)
	Compute the Gaussian-equivalent sigma for the ionisation loss fluctuations.
float	computeEnergyLossLandauSigmaQOverP (const MaterialSlab &slab, float m, float qOverP, float absQ)
	Compute the Gaussian-equivalent sigma of q/p due to ionisation fluctuations.
float	computeEnergyLossMean (const MaterialSlab &slab, PdgParticle absPdg, float m, float qOverP, float absQ)
	Compute the combined mean energy loss.
float	computeEnergyLossMode (const MaterialSlab &slab, PdgParticle absPdg, float m, float qOverP, float absQ)
	Compute the combined most probably energy loss.
float	computeEnergyLossRadiative (const MaterialSlab &slab, PdgParticle absPdg, float m, float qOverP, float absQ)
	Compute the mean energy loss due to radiative effects at high energies.
float	computeMultipleScatteringTheta0 (const MaterialSlab &slab, PdgParticle absPdg, float m, float qOverP, float absQ)
	Compute the core width of the projected planar scattering distribution.
template<typename out_t, typename sign_t>
constexpr out_t	copySign (const out_t &copyTo, const sign_t &sign)
	Copies the sign of a signed variable onto the copyTo input object.
template<typename InputVector>
auto	createCurvilinearUnitU (const Eigen::MatrixBase< InputVector > &direction)
	Construct the first curvilinear unit vector U for the given direction.
template<typename InputVector>
auto	createCurvilinearUnitVectors (const Eigen::MatrixBase< InputVector > &direction)
	Construct the curvilinear unit vectors U and V for the given direction.
Grid2D	createGrid (MaterialGridAxisData gridAxis1, MaterialGridAxisData gridAxis2)
	Helper method that creates the cache grid for the mapping.
Grid3D	createGrid (MaterialGridAxisData gridAxis1, MaterialGridAxisData gridAxis2, MaterialGridAxisData gridAxis3)
	Helper method that creates the cache grid for the mapping.
Grid2D	createGrid2D (const BinUtility &bins, std::function< Acts::Vector2(Acts::Vector3)> &transfoGlobalToLocal)
	Create a 2DGrid using a BinUtility.
Grid3D	createGrid3D (const BinUtility &bins, std::function< Acts::Vector3(Acts::Vector3)> &transfoGlobalToLocal)
	Create a 3DGrid using a BinUtility.
template<class T, class decorator_t>
void	decorateJson (const decorator_t *decorator, const T &src, nlohmann::json &dest)
	Decorate JSON with additional information from the decorator.
template<class T, class decorator_t>
void	decorateJson (const decorator_t *decorator, const T *src, nlohmann::json &dest)
	Decorate JSON with additional information from the decorator (pointer version).
float	deriveEnergyLossBetheQOverP (const MaterialSlab &slab, float m, float qOverP, float absQ)
	Derivative of the Bethe energy loss with respect to q/p.
float	deriveEnergyLossLandauQOverP (const MaterialSlab &slab, float m, float qOverP, float absQ)
	Derivative of the most probable ionisation energy loss with respect to q/p.
float	deriveEnergyLossMeanQOverP (const MaterialSlab &slab, PdgParticle absPdg, float m, float qOverP, float absQ)
	Derivative of the combined mean energy loss with respect to q/p.
float	deriveEnergyLossModeQOverP (const MaterialSlab &slab, PdgParticle absPdg, float m, float qOverP, float absQ)
	Derivative of the combined most probable energy loss with respect to q/p.
float	deriveEnergyLossRadiativeQOverP (const MaterialSlab &slab, PdgParticle absPdg, float m, float qOverP, float absQ)
	Derivative of the mean radiative energy loss with respect to q/p.
OuterStripSpacePointCalibrationDetailsDerived	deriveOuterStripSpacePointCalibrationDetails (const OuterStripSpacePointCalibrationDetails &sp)
	Derives the strip space point calibration details.
template<std::size_t FullSize> requires (FullSize <= 8)
static SubspaceIndices< FullSize >	deserializeSubspaceIndices (SerializedSubspaceIndices serialized)
	Deserialize subspace indices from a single 64 bit integer.
template<std::ranges::range container_type, typename index_type = typename detail::EnumerateIndexType<container_type>::type, typename container_type_iter = decltype(std::begin(std::declval<container_type>()))>
constexpr auto	enumerate (container_type &&iterable)
	Helper utility to allow indexed enumeration with structured binding.
BoundMatrix	estimateTrackParamCovariance (const EstimateTrackParamCovarianceConfig &config, const BoundVector &params, bool hasTime)
	Estimate the covariance matrix of the given track parameters based on the provided configuration.
Result< BoundVector >	estimateTrackParamsFromSeed (const GeometryContext &gctx, const Surface &surface, const Vector3 &sp0, double t0, const Vector3 &sp1, const Vector3 &sp2, const Vector3 &bField)
	Estimate bound track parameters from three space points.
template<std::ranges::range space_point_range_t>
Result< BoundVector >	estimateTrackParamsFromSeed (const GeometryContext &gctx, space_point_range_t spRange, const Surface &surface, const Vector3 &bField)
	Estimate bound track parameters from three space points.
FreeVector	estimateTrackParamsFromSeed (const Vector3 &sp0, const Vector3 &sp1, const Vector3 &sp2, const Vector3 &bField)
	Estimate free track parameters from three space points.
FreeVector	estimateTrackParamsFromSeed (const Vector3 &sp0, double t0, const Vector3 &sp1, const Vector3 &sp2, const Vector3 &bField, Vector3 *tangent0=nullptr, Vector3 *tangent1=nullptr, Vector3 *tangent2=nullptr)
	Estimate free track parameters from three space points.
template<std::ranges::range space_point_range_t>
FreeVector	estimateTrackParamsFromSeed (space_point_range_t spRange, const Vector3 &bField)
	Estimate free track parameters from three space points.
template<typename queries_type, typename expansion_type, std::size_t kDIM>
void	expand (queries_type &gridQueries, const expansion_type &referenceExpansion)
	Helper method to expand the grid queries along a given dimension.
static constexpr std::pair< std::int32_t, std::int32_t >	extractNucleusZandA (PdgParticle pdg)
	Extract Z and A for a given nucleus.
template<TrackContainerFrontend track_container_t, typename propagator_t, typename propagator_options_t>
Result< void >	extrapolateTracksToReferenceSurface (const track_container_t &trackContainer, const Surface &referenceSurface, const propagator_t &propagator, propagator_options_t options, TrackExtrapolationStrategy strategy, const Logger &logger= *getDefaultLogger("TrackExtrapolation", Logging::INFO))
	Extrapolate tracks to a reference surface.
template<TrackProxyConcept track_proxy_t, typename propagator_t, typename propagator_options_t>
Result< void >	extrapolateTrackToReferenceSurface (track_proxy_t &track, const Surface &referenceSurface, const propagator_t &propagator, propagator_options_t options, TrackExtrapolationStrategy strategy, const Logger &logger= *getDefaultLogger("TrackExtrapolation", Logging::INFO))
	Extrapolate a track to a reference surface.
template<std::unsigned_integral T>
constexpr T	factorial (const T N)
	Calculate the the factorial of an integer.
template<typename T, typename... Args>
constexpr auto	fastCathetus (T hypotenuse, Args... args)
	Fast cathetus calculation for multiple arguments.
template<typename T>
constexpr auto	fastHypot (T arg)
	Overload for single argument.
template<typename... T>
constexpr auto	fastHypot (T... args)
	Fast hypotenuse calculation for multiple arguments.
Acts::InterpolatedBFieldMap< Acts::Grid< Acts::Vector2, Acts::Axis< Acts::AxisType::Equidistant >, Acts::Axis< Acts::AxisType::Equidistant > > >	fieldMapRZ (const std::function< std::size_t(std::array< std::size_t, 2 > binsRZ, std::array< std::size_t, 2 > nBinsRZ)> &localToGlobalBin, std::vector< double > rPos, std::vector< double > zPos, const std::vector< Acts::Vector2 > &bField, double lengthUnit=UnitConstants::mm, double BFieldUnit=UnitConstants::T, bool firstQuadrant=false)
	Method to set up the FieldMap.
Acts::InterpolatedBFieldMap< Acts::Grid< Acts::Vector3, Acts::Axis< Acts::AxisType::Equidistant >, Acts::Axis< Acts::AxisType::Equidistant >, Acts::Axis< Acts::AxisType::Equidistant > > >	fieldMapXYZ (const std::function< std::size_t(std::array< std::size_t, 3 > binsXYZ, std::array< std::size_t, 3 > nBinsXYZ)> &localToGlobalBin, std::vector< double > xPos, std::vector< double > yPos, std::vector< double > zPos, const std::vector< Acts::Vector3 > &bField, double lengthUnit=UnitConstants::mm, double BFieldUnit=UnitConstants::T, bool firstOctant=false)
	Method to set up the FieldMap.
template<typename T, std::size_t N>
constexpr std::array< T, N >	filledArray (const T &defVal)
	creates an array of type T and size N and assigns all elements to the parsed default value def_val.
std::optional< float >	findCharge (PdgParticle pdg)
	Find the charge for a given PDG particle number.
float	findChargeOfNucleus (PdgParticle pdg)
	Find the charge for a given PDG particle number of a nucleus.
template<TrackProxyConcept track_proxy_t>
Result< typename track_proxy_t::ConstTrackStateProxy >	findFirstMeasurementState (const track_proxy_t &track)
	Find the first measurement state in a track.
template<TrackProxyConcept track_proxy_t>
Result< typename track_proxy_t::ConstTrackStateProxy >	findLastMeasurementState (const track_proxy_t &track)
	Find the last measurement state in a track.
std::optional< float >	findMass (PdgParticle pdg)
	Find the mass for a given PDG particle number.
float	findMassOfNucleus (PdgParticle pdg)
	Find the mass for a given PDG particle number of a nucleus.
std::optional< std::string_view >	findName (PdgParticle pdg)
	Find a descriptive particle name for a given PDG particle number.
std::optional< std::string_view >	findNameOfNucleus (PdgParticle pdg)
	Find a descriptive particle name for a given PDG particle number of a nucleus.
std::optional< ParticleData >	findParticleData (PdgParticle pdg)
	Find all known particle data for a given PDG particle number.
template<TrackProxyConcept track_proxy_t>
Result< std::pair< typename track_proxy_t::ConstTrackStateProxy, double > >	findTrackStateForExtrapolation (const GeometryContext &geoContext, const track_proxy_t &track, const Surface &referenceSurface, TrackExtrapolationStrategy strategy, const Logger &logger= *getDefaultLogger("TrackExtrapolation", Logging::INFO))
	Find a track state for extrapolation.
Matrix< 2, 3 >	freeToSphericalDirectionJacobian (const Vector3 &direction)
	Calculates the Jacobian for free to spherical direction vector transformation.
void	from_json (const nlohmann::json &j, BinningData &bd)
	Convert JSON to BinningData.
void	from_json (const nlohmann::json &j, BinUtility &bu)
	Convert JSON to BinUtility.
void	from_json (const nlohmann::json &j, ConfigPair &p)
	Convert JSON to ConfigPair.
void	from_json (const nlohmann::json &j, Direction &direction)
	Convert JSON to Direction.
void	from_json (const nlohmann::json &j, Extent &e)
	Convert JSON to Extent.
void	from_json (const nlohmann::json &j, ExtentEnvelope &e)
	Convert JSON to ExtentEnvelope.
void	from_json (const nlohmann::json &j, GeometryIdentifier &geoId)
	Read from JSON.
void	from_json (const nlohmann::json &j, Material &t)
	Convert JSON to Material.
void	from_json (const nlohmann::json &j, MaterialSlab &t)
	Convert JSON to MaterialSlab.
void	from_json (const nlohmann::json &j, MaterialSlabMatrix &t)
	Convert JSON to MaterialSlabMatrix.
void	from_json (const nlohmann::json &j, PolynomialBetheHeitlerApprox::PolyData &data)
	Deserialize polynomial component data from JSON.
void	from_json (const nlohmann::json &j, PolynomialBetheHeitlerApprox::RangeData &data)
	Deserialize a single x/x0 range with its data from JSON.
template<typename Type>
void	from_json (const nlohmann::json &j, Range1D< Type > &r)
	Convert JSON to Range1D.
void	from_json (const nlohmann::json &j, SeedConfirmationRangeConfig &config)
	Convert JSON to SeedConfirmationRangeConfig.
void	from_json (const nlohmann::json &j, surfaceMaterialPointer &material)
	Convert JSON to surfaceMaterialPointer.
void	from_json (const nlohmann::json &j, Transform3 &t)
	Convert JSON to Transform3.
void	from_json (const nlohmann::json &j, volumeMaterialPointer &material)
	Convert JSON to volumeMaterialPointer.
std::unique_ptr< const Logger >	getDefaultLogger (const std::string &name, const Logging::Level &lvl, std::ostream *log_stream=&std::cout)
	get default debug output logger
const Logger &	getDummyLogger ()
	Get a dummy logger that discards all output.
std::function< double(Acts::Vector3)>	globalToLocalFromBin (Acts::AxisDirection &type)
	return a function that return the coordinate corresponding to type of bin
template<typename T, class... Axes>
	Grid (TypeTag< T >, Axes &&... axes) -> Grid< T, Axes... >
	Deduction guide for Grid with rvalue reference axes.
template<typename T, class... Axes>
	Grid (TypeTag< T >, Axes &... axes) -> Grid< T, Axes... >
	Deduction guide for Grid with lvalue reference axes.
template<typename T, class... Axes>
	GridGlobalIterator (const Grid< T, Axes... > &grid, std::size_t idx) -> GridGlobalIterator< T, Axes... >
	Deduction guide for GridGlobalIterator.
constexpr std::uint64_t	hashMix (std::uint64_t x)
	Apply a bit-mixing function to break up patterns in integer hash values.
template<typename T, typename... Rest>
constexpr std::uint64_t	hashMixAndCombine (const T &value, const Rest &... rest)
	Combine one or more values into a single hash.
consteval HashedString	hashString (std::string_view s)
	Compile-time hash of string literal.
constexpr HashedString	hashStringDynamic (std::string_view s)
	Runtime hash of string.
template<typename... T>
constexpr auto	hypotSquare (T... args)
	Calculates the sum of squares of arguments.
template<typename T, std::size_t N, class Point1, class Point2 = Point1, class Point3 = Point2> requires Concepts::Interpolatable<T, N, Point1, Point2, Point3>
T	interpolate (const Point1 &point, const Point2 &lowerCorner, const Point3 &upperCorner, const std::array< T, N > &values)
	performs linear interpolation inside a hyper box
template<typename T>
consteval T	ipow (T num, unsigned int pow)
	Calculate the integer power of a number at compile time using recursion.
bool	isBoundVectorValid (const BoundVector &v, bool validateAngleRange, double epsilon=1e-6, double maxAbsEta=std::numeric_limits< double >::infinity())
	Check if a bound vector is valid.
bool	isFreeVectorValid (const FreeVector &v, double epsilon=1e-6, double maxAbsEta=std::numeric_limits< double >::infinity())
	Check if a free vector is valid.
static constexpr bool	isNucleus (PdgParticle pdg)
	Check if the PDG belongs to a nucleus, i.e.
template<std::ranges::range R> requires std::convertible_to<std::ranges::range_value_t<R>, std::string_view>
std::string	joinStrings (R &&strings, std::string_view delimiter)
	Utuility to join a range of strings with a delimiter.
template<std::ranges::range R> requires detail::formattable<std::ranges::range_value_t<R>, char>
std::string	joinStrings (R &&values, std::string_view delimiter, std::format_string< const std::ranges::range_value_t< R > & > format)
	Utility to join a range of formattable elements with a delimiter and custom format string.
PolynomialBetheHeitlerApprox	loadBetheHeitlerApproxFromJson (const std::string &filepath, bool clampToRange=false, double noChangeLimit=0.0001, double singleGaussianLimit=0.002)
	Load a Bethe-Heitler approximation from a JSON file.
std::shared_ptr< TrackingGeometry >	loadDD4hepGeometryModule (const std::filesystem::path &modulePath, const dd4hep::Detector &detector, const Logger &logger=getDummyLogger())
	Load a DD4hep geometry module shared library with the given detector, validate ABI compatibility, build and return the tracking geometry.
std::shared_ptr< TrackingGeometry >	loadGeometryModule (const std::filesystem::path &modulePath, const Logger &logger=getDummyLogger())
	Load a module shared library, validate ABI compatibility, build and return the tracking geometry.
template<typename grid_type>
std::set< typename grid_type::index_t >	localIndices (const grid_type &grid, const std::vector< typename grid_type::point_t > &queries, const std::vector< std::size_t > &expansion={})
	Helper method to fill local bins given a set of query points bin in between the extra points are filled, and a possible expansion of the bin window can be chosen.
std::error_code	make_error_code (Acts::CombinatorialKalmanFilterError e)
	Create error code from CombinatorialKalmanFilterError.
std::error_code	make_error_code (Acts::KalmanFitterError e)
	Create error code from KalmanFitterError.
std::error_code	make_error_code (Acts::MultiStepperError e)
	Create error code from MultiStepperError.
std::error_code	make_error_code (Acts::NavigatorError e)
	Create error code from NavigatorError.
std::error_code	make_error_code (Acts::PortalError e)
	Create error code from PortalError.
std::error_code	make_error_code (Acts::PropagatorError e)
	Create error code from PropagatorError.
std::error_code	make_error_code (Acts::SurfaceError e)
	Create error code from SurfaceError.
std::error_code	make_error_code (Acts::VertexingError e)
	Create error code from VertexingError.
std::error_code	make_error_code (EigenStepperError e)
	Create error code from EigenStepperError.
std::error_code	make_error_code (GsfError e)
	Create error code from GsfError.
std::error_code	make_error_code (SpacePointFormationError e)
	Create error code from SpacePointFormationError.
std::error_code	make_error_code (TrackExtrapolationError e)
	Create error code from TrackExtrapolationError.
template<typename box_t>
box_t *	make_octree (std::vector< std::unique_ptr< box_t > > &store, const std::vector< box_t * > &prims, std::size_t max_depth=1, typename box_t::value_type envelope1=0)
	Build an octree from a list of bounding boxes.
static constexpr PdgParticle	makeAbsolutePdgParticle (PdgParticle pdg)
	Convert an anti-particle to its particle and leave particles as-is.
PolynomialBetheHeitlerApprox	makeDefaultBetheHeitlerApprox (bool clampToRange=false)
	Creates a PolynomialBetheHeitlerApprox object based on a default configuration, stored as static data in the source code.
template<typename T>
Eigen::Matrix< T, 3, 1 >	makeDirectionFromAxisTangents (T tanAlpha, T tanBeta)
	Construct a normalized direction vector from the tangents of the x-axis to the z-axis and of the y-axis to the z-axis.
template<typename T>
Eigen::Matrix< T, 3, 1 >	makeDirectionFromPhiEta (T phi, T eta)
	Construct a normalized direction vector from phi angle and pseudorapidity.
template<typename T>
Eigen::Matrix< T, 3, 1 >	makeDirectionFromPhiTheta (T phi, T theta)
	Construct a normalized direction vector from phi and theta angle.
template<typename payload_t>
std::unique_ptr< IGrid >	makeGrid (const IAxis &a)
	Helper method to create a 1D grid from a single type-erased axis.
template<typename payload_t>
std::unique_ptr< IGrid >	makeGrid (const IAxis &a, const IAxis &b)
	Helper method to create a 2D grid from two type-erased axes.
template<typename payload_t>
std::unique_ptr< IGrid >	makeGrid (const ProtoAxis &a)
	Helper method to create a 1D grid from a single proto axis.
template<typename payload_t>
std::unique_ptr< IGrid >	makeGrid (const ProtoAxis &a, const ProtoAxis &b)
	Helper method to create a 2D grid from a two proto axes.
InterpolatedBFieldMap< Grid< Vector2, Axis< AxisType::Equidistant >, Axis< AxisType::Equidistant > > >	makeMagneticFieldMapRzFromText (const std::function< std::size_t(std::array< std::size_t, 2 > binsRZ, std::array< std::size_t, 2 > nBinsRZ)> &localToGlobalBin, const std::string &fieldMapFile, double lengthUnit, double BFieldUnit, bool firstQuadrant=false, const std::string &delimiter="")
	Method to set up the FieldMapper.
InterpolatedBFieldMap< Grid< Vector3, Axis< AxisType::Equidistant >, Axis< AxisType::Equidistant >, Axis< AxisType::Equidistant > > >	makeMagneticFieldMapXyzFromText (const std::function< std::size_t(std::array< std::size_t, 3 > binsXYZ, std::array< std::size_t, 3 > nBinsXYZ)> &localToGlobalBin, const std::string &fieldMapFile, double lengthUnit, double BFieldUnit, bool firstOctant=false, const std::string &delimiter="")
	Method to set up the FieldMapper.
static constexpr PdgParticle	makeNucleusGroundState (PdgParticle pdg)
	Convert an excited nucleus to its ground state.
template<typename T>
Eigen::Matrix< T, 2, 1 >	makePhiThetaFromDirection (const Eigen::Matrix< T, 3, 1 > &unitDir)
	Construct a phi and theta angle from a direction vector.
MaterialGrid2D	mapMaterialPoints (Grid2D &grid)
	Average the material collected in a 2D grid and use it to create a 2D material grid.
MaterialGrid3D	mapMaterialPoints (Grid3D &grid)
	Average the material collected in a 3D grid and use it to create a 3D material grid.
MaterialMapLookup< Grid< Material::ParametersVector, Axis< Acts::AxisType::Equidistant >, Axis< Acts::AxisType::Equidistant > > >	materialMapperRZ (const std::function< std::size_t(std::array< std::size_t, 2 > binsRZ, std::array< std::size_t, 2 > nBinsRZ)> &materialVectorToGridMapper, std::vector< double > rPos, std::vector< double > zPos, const std::vector< Acts::Material > &material, double lengthUnit=UnitConstants::mm)
	Method to set up the MaterialMapper.
MaterialMapLookup< Grid< Material::ParametersVector, Axis< Acts::AxisType::Equidistant >, Axis< Acts::AxisType::Equidistant >, Axis< Acts::AxisType::Equidistant > > >	materialMapperXYZ (const std::function< std::size_t(std::array< std::size_t, 3 > binsXYZ, std::array< std::size_t, 3 > nBinsXYZ)> &materialVectorToGridMapper, std::vector< double > xPos, std::vector< double > yPos, std::vector< double > zPos, const std::vector< Material > &material, double lengthUnit=UnitConstants::mm)
	Method to set up the MaterialLookup.
template<typename Derived>
auto	matrixToBitset (const Eigen::PlainObjectBase< Derived > &m)
	Convert an integer matrix to a bitset.
BoundVector	normalizeBoundParameters (const BoundVector &boundParams)
	Normalize the bound parameter angles.
constexpr std::size_t	numAxisDirections ()
	Returns the total number of axis directions.
std::ostream &	operator<< (std::ostream &os, AxisBoundaryType bdt)
	Stream operator for AxisBoundaryType.
std::ostream &	operator<< (std::ostream &os, AxisDirection aDir)
	Output stream operator for AxisDirection.
std::ostream &	operator<< (std::ostream &os, AxisType type)
	Stream operator for AxisType.
std::ostream &	operator<< (std::ostream &os, BoundarySurfaceFace &face)
	Stream operator for BoundarySurfaceFace.
template<typename T, typename U, std::size_t V>
std::ostream &	operator<< (std::ostream &os, const AxisAlignedBoundingBox< T, U, V > &box)
	Overload of the << operator for bounding boxes.
std::ostream &	operator<< (std::ostream &os, const ConstrainedStep &step)
	Stream operator for ConstrainedStep.
std::ostream &	operator<< (std::ostream &os, const IVisualization3D &hlp)
	Stream operator for IVisualization3D.
std::ostream &	operator<< (std::ostream &os, const Material &material)
	Stream operator for Material.
std::ostream &	operator<< (std::ostream &os, const MaterialSlab &materialSlab)
	Stream operator for MaterialSlab.
template<typename T, std::size_t D>
std::ostream &	operator<< (std::ostream &os, const Ray< T, D > &ray)
	Overload of the outstream operator.
std::ostream &	operator<< (std::ostream &os, const std::vector< AxisDirection > &manyDir)
	Output stream operator for a vector of AxisDirection.
std::ostream &	operator<< (std::ostream &os, const std::vector< DirectedProtoAxis > &a)
	Stream operator for vector of DirectedProtoAxis.
std::ostream &	operator<< (std::ostream &os, const std::vector< ProtoAxis > &a)
	Stream operator for vector of ProtoAxis.
std::ostream &	operator<< (std::ostream &os, const TrackSelector::Config &cuts)
std::ostream &	operator<< (std::ostream &os, const TrackSelector::EtaBinnedConfig &cfg)
std::ostream &	operator<< (std::ostream &os, CuboidPortalShell::Face face)
	Output stream operator for the CuboidPortalShell::Face enum.
std::ostream &	operator<< (std::ostream &os, CylinderPortalShell::Face face)
	Output stream operator for the CylinderPortalShell::Face enum.
std::ostream &	operator<< (std::ostream &os, DiamondPortalShell::Face face)
std::ostream &	operator<< (std::ostream &os, GeometryIdentifier id)
	Stream operator for GeometryIdentifier.
std::ostream &	operator<< (std::ostream &os, HadronType hadron)
	Stream operator for HadronType.
std::ostream &	operator<< (std::ostream &os, IntersectionStatus status)
	Ostream-operator for the IntersectionStatus enum.
std::ostream &	operator<< (std::ostream &os, MaterialUpdateMode mode)
	Stream operator for MaterialUpdateMode.
std::ostream &	operator<< (std::ostream &os, PdgParticle pdg)
	Print PDG particle numbers with a descriptive name.
std::ostream &	operator<< (std::ostream &os, TrackStatePropMask mask)
	Stream operator for TrackStatePropMask.
std::ostream &	operator<< (std::ostream &os, TrapezoidPortalShell::Face face)
	Output stream operator for the TrapezoidPortalShell::Face enum.
std::ostream &	operator<< (std::ostream &os, VolumeAttachmentStrategy strategy)
	Stream operator for VolumeAttachmentStrategy.
std::ostream &	operator<< (std::ostream &os, VolumeResizeStrategy strategy)
	Stream operator for VolumeResizeStrategy.
std::ostream &	operator<< (std::ostream &sl, const Extent &rhs)
	Overload of << operator for std::ostream for debug output.
std::ostream &	operator<< (std::ostream &sl, const GlueVolumesDescriptor &gvd)
	Stream operator for GlueVolumesDescriptor.
std::ostream &	operator<< (std::ostream &sl, const Volume &vol)
	Overload of << operator for std::ostream for debug output.
std::ostream &	operator<< (std::ostream &sl, const VolumeBounds &vb)
	Overload of << operator for std::ostream for debug output.
std::ostream &	operator<< (std::ostream &sl, const VolumeBounds::BoundsType &bt)
	Stream operator for VolumeBounds::BoundsType.
bool	operator== (const VolumeBounds &lhs, const VolumeBounds &rhs)
	Equality comparison for VolumeBounds.
template<typename local_bin>
std::string	outputIndices (const std::set< local_bin > &lbins)
	Helper method to screen output the local bins.
template<class... Ts>
	overloaded (Ts...) -> overloaded< Ts... >
	Deduction guide for overloaded visitor pattern.
PdgParticle	parsePdgParticle (const std::string &name)
	Parse a PdgParticle from a particle name string.
std::optional< std::string_view >	pdgToShortAbsString (PdgParticle pdg)
	Get short absolute string representation of PDG particle.
template<typename T, std::integral P>
constexpr T	pow (T x, P p)
	Calculates the ordinary power of the number x.
std::string	printEigenDecomposition (const Eigen::Ref< const Eigen::MatrixXd > &mat)
	Print the eigen decomposition of a symmetric matrix in terms of eigen values and eigen vectors.
template<std::unsigned_integral T>
constexpr T	product (const T lowerN, const T upperN)
	Calculates the product of all integers within the given integer range (nLower)(nLower+1)(...)(upper-1)(upper).
template<std::size_t kFullSize, typename Derived>
SubspaceIndices< kFullSize >	projectorToSubspaceIndices (const Eigen::DenseBase< Derived > &projector)
	Convert a projector to subspace indices.
template<typename T>
std::tuple< typename T::value_type, double >	range_medium (const T &tseries)
	Return range and medium of an unsorted numeric series.
template<typename R>
bool	rangeContainsSubstring (const R &range, std::string_view value)
	This function checks if at least one string from a given range is contained within a specified string (value).
template<typename R, typename T>
bool	rangeContainsValue (const R &range, const T &value)
	This can be replaced with C++23 to use the std::ranges::contains method.
void	reduceMixtureLargestWeights (std::vector< GsfComponent > &cmpCache, std::size_t maxCmpsAfterMerge, const Surface &surface)
	Very simple mixture reduction method: Just removes the components with the smallest weight until the required number of components is reached.
void	reduceMixtureWithKLDistance (std::vector< GsfComponent > &cmpCache, std::size_t maxCmpsAfterMerge, const Surface &surface)
	Greedy component reduction algorithm.
void	reduceMixtureWithKLDistanceNaive (std::vector< GsfComponent > &cmpCache, std::size_t maxCmpsAfterMerge, const Surface &surface)
	Naive implementation of component reduction with KL-distance.
BoundVector	reflectBoundParameters (const BoundVector &boundParams)
	Reflect bound track parameters.
FreeVector	reflectFreeParameters (const FreeVector &freeParams)
	Reflect free track parameters.
template<typename T>
constexpr T	safeExp (T val) noexcept
	Calculate the exponential function while avoiding FPEs.
template<typename MatrixType, typename ResultType = MatrixType>
std::optional< ResultType >	safeInverse (const MatrixType &m) noexcept
	FPE "safe" functions.
template<std::size_t FullSize> requires (FullSize <= 8)
static SerializedSubspaceIndices	serializeSubspaceIndices (const SubspaceIndices< FullSize > &indices)
	Serialize subspace indices to a single 64 bit integer.
double	sinc (double x)
	Calculate the sinc function, defined as sin(x)/x, with a special handling for x=0 to avoid numerical instability.
template<typename T, typename... Args>
constexpr auto	slowCathetus (T hypotenuse, Args... args)
	Slow but more accurate cathetus calculation for multiple arguments.
template<typename T>
constexpr auto	slowHypot (T arg)
	Overload for single argument.
template<typename T>
constexpr auto	slowHypot (T x, T y)
	Overload for two arguments.
template<typename T>
constexpr auto	slowHypot (T x, T y, T z)
	Overload for three arguments.
template<typename... T>
constexpr auto	slowHypot (T... args)
	Slow but more accurate hypotenuse calculation for multiple arguments.
template<TrackProxyConcept track_proxy_t, typename smoother_t = GainMatrixSmoother>
Result< void >	smoothTrack (const GeometryContext &geoContext, track_proxy_t &track, const Logger &logger= *getDefaultLogger("TrackSmoother", Logging::INFO), smoother_t smoother=GainMatrixSmoother())
	Smooth a track using the gain matrix smoother.
template<TrackContainerFrontend track_container_t>
Result< void >	smoothTracks (const GeometryContext &geoContext, const track_container_t &trackContainer, const Logger &logger= *getDefaultLogger("TrackSmoother", Logging::INFO))
	Smooth tracks using the gain matrix smoother.
Acts::InterpolatedBFieldMap< Acts::Grid< Acts::Vector2, Acts::Axis< Acts::AxisType::Equidistant >, Acts::Axis< Acts::AxisType::Equidistant > > >	solenoidFieldMap (const std::pair< double, double > &rLim, const std::pair< double, double > &zLim, const std::pair< std::size_t, std::size_t > &nBins, const SolenoidBField &field)
	Function which takes an existing SolenoidBField instance and creates a field mapper by sampling grid points from the analytical solenoid field.
Matrix< 3, 2 >	sphericalToFreeDirectionJacobian (const Vector3 &direction)
	Calculates the Jacobian for spherical to free direction vector transformation.
template<typename T>
constexpr auto	square (T x)
	Returns the square of the passed number.
BoundVector	subtractBoundParameters (const BoundVector &lhs, const BoundVector &rhs)
	Subtract bound parameters and take care of angle periodicity for phi and theta.
template<std::integral T>
constexpr T	sumUpToN (const T N)
	Calculates the sum of 1 + 2 + 3+ ... + N using the Gaussian sum formula.
template<std::size_t N> requires (N > 1)
constexpr std::array< std::size_t, 2 >	symMatIndices (const std::size_t k)
	Map an unrolled vector index to the indices of the lower triangular part of a symmetric N x N matrix.
template<template< std::size_t > class Callable, std::size_t N, std::size_t NMAX, typename... Args>
decltype(auto)	template_switch (std::size_t v, Args &&... args)
	Dispatch a call based on a runtime value on a function taking the value at compile time.
template<std::size_t N, std::size_t NMAX, typename Lambda, typename... Args>
decltype(auto)	template_switch_lambda (std::size_t v, Lambda &&func, Args &&... args)
	Alternative version of template_switch which accepts a generic lambda and communicates the dimension via an integral constant type.
void	to_json (nlohmann::json &j, const Acts::TrackingVolume &volume)
	Convert TrackingVolume to JSON.
void	to_json (nlohmann::json &j, const BinningData &bd)
	Convert BinningData to JSON.
void	to_json (nlohmann::json &j, const BinUtility &bu)
	Convert BinUtility to JSON.
void	to_json (nlohmann::json &j, const Direction &direction)
	Convert Direction to JSON.
void	to_json (nlohmann::json &j, const Extent &e)
	Convert Extent to JSON.
void	to_json (nlohmann::json &j, const ExtentEnvelope &e)
	Convert ExtentEnvelope to JSON.
void	to_json (nlohmann::json &j, const GeometryIdentifier &geoId)
	Write to JSON.
void	to_json (nlohmann::json &j, const Material &t)
	Convert Material to JSON.
void	to_json (nlohmann::json &j, const MaterialSlab &t)
	Convert MaterialSlab to JSON.
void	to_json (nlohmann::json &j, const PolynomialBetheHeitlerApprox::PolyData &data)
	Serialize polynomial component data to JSON.
void	to_json (nlohmann::json &j, const PolynomialBetheHeitlerApprox::RangeData &data)
	Serialize a single x/x0 range with its data to JSON.
template<typename Type>
void	to_json (nlohmann::json &j, const Range1D< Type > &r)
	Convert Range1D to JSON.
void	to_json (nlohmann::json &j, const SeedConfirmationRangeConfig &config)
	Convert SeedConfirmationRangeConfig to JSON.
void	to_json (nlohmann::json &j, const std::pair< const Acts::TrackingVolume *, std::shared_ptr< const Acts::IVolumeMaterial > > &volume)
	Convert tracking volume and material pair to JSON.
void	to_json (nlohmann::json &j, const std::shared_ptr< const Surface > &surface)
	Convert shared_ptr<Surface> to JSON.
void	to_json (nlohmann::json &j, const Surface &surface)
	Convert Surface to JSON.
void	to_json (nlohmann::json &j, const SurfaceAndMaterialWithContext &surface)
	Convert SurfaceAndMaterialWithContext to JSON.
void	to_json (nlohmann::json &j, const SurfaceBounds &bounds)
	Convert SurfaceBounds to JSON.
void	to_json (nlohmann::json &j, const surfaceMaterialPointer &material)
	Convert surfaceMaterialPointer to JSON.
void	to_json (nlohmann::json &j, const Transform3 &t)
	Convert Transform3 to JSON.
void	to_json (nlohmann::json &j, const VolumeBounds &bounds)
	Convert VolumeBounds to JSON.
void	to_json (nlohmann::json &j, const volumeMaterialPointer &material)
	Convert volumeMaterialPointer to JSON.
template<std::size_t kDIM, typename value_t>
std::array< value_t, kDIM >	toArray (const std::vector< value_t > &vecvals)
	Converts a vector to a fixed-size array with truncating or padding.
void	toJson (nlohmann::json &j, const std::shared_ptr< const Surface > &surface, const Acts::GeometryContext &gctx)
	Contextual conversion of a surface.
Acts::InterpolatedBFieldMap< Acts::Grid< Acts::Vector3, Acts::Axis< Acts::AxisType::Equidistant >, Acts::Axis< Acts::AxisType::Equidistant >, Acts::Axis< Acts::AxisType::Equidistant > > >	toroidFieldMapCyl (const std::pair< double, double > &rLim, const std::pair< double, double > &phiLim, const std::pair< double, double > &zLim, const std::tuple< std::size_t, std::size_t, std::size_t > &nBins, const ToroidField &field)
	Function which takes an existing ToroidField instance and creates a cylindrical field mapper by sampling grid points from the analytical toroidal field.
Acts::InterpolatedBFieldMap< Acts::Grid< Acts::Vector3, Acts::Axis< Acts::AxisType::Equidistant >, Acts::Axis< Acts::AxisType::Equidistant >, Acts::Axis< Acts::AxisType::Equidistant > > >	toroidFieldMapXYZ (const std::pair< double, double > &xLim, const std::pair< double, double > &yLim, const std::pair< double, double > &zLim, const std::tuple< std::size_t, std::size_t, std::size_t > &nBins, const ToroidField &field)
	Function which takes an existing ToroidField instance and creates a Cartesian field mapper by sampling grid points from the analytical toroidal field.
std::string	toString (const Acts::Transform3 &transform, int precision=4, const std::string &offset="")
	Print out a transform in a structured way.
std::string	toString (const Acts::Translation3 &translation, int precision=4)
	Print out a translation in a structured way.
template<typename derived_t>
std::string	toString (const Eigen::MatrixBase< derived_t > &matrix, int precision=4, const std::string &offset="")
	Print out a matrix in a structured way.
std::string	toString (const std::vector< double > &pVector, int precision=4)
	Print out a vector of double.
template<typename enum_t>
constexpr std::underlying_type_t< enum_t >	toUnderlying (enum_t value)
	Convert enum to its underlying type value.
template<TrackContainerBackend track_container_t, typename traj_t>
	TrackContainer (const track_container_t &container, const traj_t &traj) -> TrackContainer< track_container_t, traj_t, ConstRefHolder >
	Deduction guide for TrackContainer with const references.
template<TrackContainerBackend track_container_t, typename traj_t>
	TrackContainer (track_container_t &&container, traj_t &&traj) -> TrackContainer< track_container_t, traj_t, ValueHolder >
	Deduction guide for TrackContainer with rvalue references.
template<TrackContainerBackend track_container_t, typename traj_t>
	TrackContainer (track_container_t &container, traj_t &traj) -> TrackContainer< track_container_t, traj_t, RefHolder >
	Deduction guide for TrackContainer with lvalue references.
FreeVector	transformBoundToFreeParameters (const Surface &surface, const GeometryContext &geoCtx, const BoundVector &boundParams)
	Transform bound track parameters into equivalent free track parameters.
Result< BoundVector >	transformFreeToBoundParameters (const FreeVector &freeParams, const Surface &surface, const GeometryContext &geoCtx, double tolerance=s_onSurfaceTolerance)
	Convert free track parameters to bound track parameters.
Result< BoundVector >	transformFreeToBoundParameters (const Vector3 &position, double time, const Vector3 &direction, double qOverP, const Surface &surface, const GeometryContext &geoCtx, double tolerance=s_onSurfaceTolerance)
	Convert position and direction to bound track parameters.
BoundVector	transformFreeToCurvilinearParameters (double time, const Vector3 &direction, double qOverP)
	Convert direction to curvilinear track parameters.
BoundVector	transformFreeToCurvilinearParameters (double time, double phi, double theta, double qOverP)
	Convert direction angles to curvilinear track parameters.
template<TrackProxyConcept track_proxy_t> requires (!track_proxy_t::ReadOnly)
void	trimTrack (track_proxy_t track, bool trimHoles, bool trimOutliers, bool trimMaterial, bool trimOtherNoneMeasurement)
	Helper function to trim track states from the front and back of a track.
template<TrackProxyConcept track_proxy_t> requires (!track_proxy_t::ReadOnly)
void	trimTrackBack (track_proxy_t track, bool trimHoles, bool trimOutliers, bool trimMaterial, bool trimOtherNoneMeasurement)
	Helper function to trim track states from the back of a track.
template<TrackProxyConcept track_proxy_t> requires (!track_proxy_t::ReadOnly)
void	trimTrackFront (track_proxy_t track, bool trimHoles, bool trimOutliers, bool trimMaterial, bool trimOtherNoneMeasurement)
	Helper function to trim track states from the front of a track.
template<typename T>
std::uint64_t	typeHash ()
	Hash for a type.
template<SmartPointerConcept T>
std::vector< std::add_pointer_t< std::add_const_t< typename T::element_type > > >	unpackConstSmartPointers (const std::vector< T > &items)
	Helper function to unpack a vector of smart pointers (e.g.
template<typename T>
std::vector< const T * >	unpackSmartPointers (const std::vector< std::shared_ptr< const T > > &items)
	Helper function to unpack a vector of shared_ptr into a vector of raw pointers (const version).
template<SmartPointerConcept T>
std::vector< std::add_pointer_t< typename T::element_type > >	unpackSmartPointers (const std::vector< T > &items)
	Helper function to unpack a vector of shared_ptr into a vector of raw pointers.
template<std::size_t N> requires (N > 0)
constexpr std::size_t	vecIdxFromSymMat (const std::size_t i, const std::size_t k)
	Map the indices of the lower triangular part of a symmetric N x N matrix to an unrolled vector index.
template<typename L, typename A, typename B>
auto	visit_measurement (const A &param, const B &cov, std::size_t dim, L &&lambda)
	Dispatch a lambda call on an overallocated parameter vector and covariance matrix, based on a runtime dimension value.
template<typename L, typename... Args>
auto	visit_measurement (std::size_t dim, L &&lambda, Args &&... args)
	Dispatch a generic lambda on a measurement dimension.
template<typename... R>
auto	zip (R &&...r)
	Function that allows to zip some ranges to be used in a range-based for loop.

Variables
constexpr auto	AxisBound = AxisBoundaryTypeTag<AxisBoundaryType::Bound>{}
	Constant for bound boundary type axis.
constexpr auto	AxisClosed = AxisBoundaryTypeTag<AxisBoundaryType::Closed>{}
	Constant for closed boundary type axis.
constexpr auto	AxisOpen = AxisBoundaryTypeTag<AxisBoundaryType::Open>{}
	Convenience typedefs for AxisBoundaryTypeTag Constant for open boundary type axis.
static constexpr BoundSubspaceIndices	kBoundSubspaceIndicesInvalid
	type alias for indices of bound track parameters subspace
static constexpr std::size_t	kMeasurementSizeMax = eBoundSize
	Maximum size of measurement dimension supported.
static constexpr std::size_t	kNavigationPolicyStateSbo = 128
	Small-buffer size (in bytes) for a type-erased navigation policy state.
static constexpr SeedIndex	kSeedIndexInvalid
	Sentinel value for an invalid / unset seed EDM related index.
static constexpr SpacePointIndex	kSpacePointIndexInvalid
	Sentinel value for an invalid / unset space point EDM related index.
static constexpr TrackIndexType	kTrackIndexInvalid
	Sentinel value for an invalid / unset track EDM related index.
static constexpr float	NoTime = std::numeric_limits<float>::quiet_NaN()
	Sentinel value for space points without timing information.
constexpr int	PolygonDynamic = -1
	Tag to trigger specialization of a dynamic polygon.
static constexpr double	s_curvilinearProjTolerance = 0.999995
	Tolerance for not being within curvilinear projection this allows using the same curvilinear frame to eta = 6, validity tested with IntegrationTests/PropagationTest.
constexpr Color	s_defaultPortalColor {"#308c48"}
	Default color for portals.
constexpr Color	s_defaultSurfaceColor {"#0000aa"}
	Default color for surfaces.
constexpr Color	s_defaultVolumColor {"#ffaa00"}
	Default color for volumes.
static constexpr double	s_epsilon = 3 * std::numeric_limits<double>::epsilon()
	Tolerance for being numerical equal for geometry building.
static constexpr IntersectionIndex	s_maximumNumberOfIntersections = 2
	Maximum number of intersections that can be stored.
static const InfiniteBounds	s_noBounds {}
	Static instance of InfiniteBounds for convenience.
static constexpr double	s_onSurfaceTolerance = 1e-4
	Tolerance for being on Surface.
static const Transform3	s_planeXY = Transform3::Identity()
	XY plane transformation (identity).
static const Transform3	s_planeYZ
	YZ plane transformation.
static const Transform3	s_planeZX
	ZX plane transformation.
constexpr double	s_transformEquivalentTolerance = 1e-9
	Tolerance for transform equivalence checks.
static ViewConfig	s_viewFiltered = {.color = {255, 255, 0}}
	View configuration for filtered states.
static const ViewConfig	s_viewGrid = {.color = {220, 0, 0}}
	View configuration for grid visualization.
static const ViewConfig	s_viewLine = {.color = {0, 0, 220}}
	View configuration for line visualization.
static ViewConfig	s_viewMeasurement = {.color = {255, 102, 0}}
	View configuration for measurements.
static ViewConfig	s_viewParameter = {.color = {0, 0, 255}}
	View configuration for track parameters.
static const ViewConfig	s_viewPassive = {.color = {240, 280, 0}}
	View configuration for passive surface visualization.
static const ViewConfig	s_viewPortal = {.color = Color{"#308c48"}}
	View configuration for portal visualization.
static ViewConfig	s_viewPredicted = {.color = {51, 204, 51}}
	View configuration for predicted states.
static const ViewConfig	s_viewSensitive = {.color = {0, 180, 240}}
	View configuration for sensitive surface visualization.
static ViewConfig	s_viewSmoothed = {.color = {0, 102, 25}}
	View configuration for smoothed states.
static const ViewConfig	s_viewSurface = {.color = {170, 170, 170}}
	View configuration for surface visualization.
static const ViewConfig	s_viewVolume = {.color = {220, 220, 0}}
	View configuration for volume visualization.
template<typename stepper_t>
constexpr bool	SupportsBoundParameters_v
	Variable template for checking bound parameters support.
template<typename T>
constexpr TypeTag< T >	Type
	Convenience variable for creating TypeTag instances.
constexpr Envelope	zeroEnvelope = {0, 0}
	Zero envelope constant for no extension.

Detailed Description

The main namespace encompassing all ACTS code.

Note

This file is foreseen for the Geometry module to replace Extent

Typedef Documentation

const_if_t

template<bool C, typename T>

using Acts::const_if_t = std::conditional_t<C, const T, T>

Type trait that adds const qualifier to a type based on a boolean condition.

Template Parameters

C	Boolean condition determining whether to add const
T	Type to potentially make const

ConstProxyAccessor

template<typename T>

using Acts::ConstProxyAccessor = ProxyAccessorBase<T, true>

Type alias for a const proxy accessor.

Provides read-only access to proxy data with const-qualified member functions

EAxis

using Acts::EAxis = Acts::Axis<AxisType::Equidistant>

Type alias for equidistant axis with open boundary type.

Used for defining grid axes with equally spaced bins and open boundaries

Envelope

using Acts::Envelope = std::array<double, 2>

Type alias for envelope values in different directions.

Stores the envelope values for both positive and negative directions

FixedBoundSubspaceHelper

template<std::size_t SubspaceSize>

using Acts::FixedBoundSubspaceHelper

Initial value:

 
    FixedSubspaceHelper<Acts::eBoundSize, SubspaceSize, std::uint8_t>

Helper type for fixed-size bound parameter subspaces.

Provides utilities for working with fixed-size subspaces of bound track parameters

Grid2D

using Acts::Grid2D = Acts::Grid<Acts::AccumulatedVolumeMaterial, EAxis, EAxis>

Type alias for a 2-dimensional grid.

Grid structure for storing values with two dimensions

Grid3D

using Acts::Grid3D = Acts::Grid<Acts::AccumulatedVolumeMaterial, EAxis, EAxis, EAxis>

Type alias for a 3-dimensional grid.

Grid structure for storing values with three dimensions

HashedString

using Acts::HashedString = std::uint32_t

Type alias for hashed string representation.

Represents a string as a compile-time hash value for efficient comparison

LayerArray

typedef BinnedArray< LayerPtr > Acts::LayerArray = BinnedArray<LayerPtr>

A BinnedArray to a std::shared_ptr of a layer.

Layers are constructed with shared_ptr factories, hence the layer array is describes as:

LayerPtr

typedef std::shared_ptr< const Layer > Acts::LayerPtr = std::shared_ptr<const Layer>

A std::shared_ptr to a Layer.

Type alias for a shared pointer to a layer.

MaterialGrid2D

using Acts::MaterialGrid2D

Initial value:

 
    Acts::Grid<Acts::Material::ParametersVector, EAxis, EAxis>

Type alias for a 2-dimensional material grid.

Grid structure for storing material parameters with two dimensions

MaterialGrid3D

using Acts::MaterialGrid3D

Initial value:

 
    Acts::Grid<Acts::Material::ParametersVector, EAxis, EAxis, EAxis>

Type alias for a 3-dimensional material grid.

Grid structure for storing material parameters with three dimensions

MaterialGridAxisData

using Acts::MaterialGridAxisData = std::tuple<double, double, std::size_t>

Type alias for the axis data in material grids.

Tuple containing the minimum value, maximum value, and number of bins for an axis

MaterialSlabMatrix

using Acts::MaterialSlabMatrix = std::vector<MaterialSlabVector>

Type alias for a matrix of material slabs.

Used to store a 2D collection of material slabs

MaterialSlabVector

using Acts::MaterialSlabVector = std::vector<MaterialSlab>

Type alias for a vector of material slabs.

Used to store a collection of material slabs in sequence

MaxMomentumReducerLoop

typedef detail::SingleComponentReducer< detail::MaxMomentumComponent > Acts::MaxMomentumReducerLoop

Initial value:

 
    detail::SingleComponentReducer<detail::MaxMomentumComponent>

Type alias for loop reducer based on maximum momentum.

Reduces multiple loop iterations based on momentum criteria

MaxWeightReducerLoop

typedef detail::SingleComponentReducer< detail::MaxWeightComponent > Acts::MaxWeightReducerLoop

Initial value:

 
    detail::SingleComponentReducer<detail::MaxWeightComponent>

Type alias for loop reducer based on maximum weight.

Reduces multiple loop iterations based on weight criteria

MultiEigenStepperLoop

template<typename extension_t = EigenStepperDefaultExtension, typename reducer_t = MaxWeightReducerLoop>

using Acts::MultiEigenStepperLoop

Initial value:

 
    MultiStepperLoop<EigenStepper<extension_t>, reducer_t>

Stepper based on the EigenStepper, but handles Multi-Component Tracks (e.g., for the GSF).

Internally, this only manages a vector of EigenStepper::States. This simplifies implementation, but has several drawbacks:

• There are certain redundancies between the global State and the component states
• The components do not share a single magnetic-field-cache

  Template Parameters

  extension_t	See EigenStepper for details
  component_reducer_t	How to map the multi-component state to a single component
  small_vector_size	A size-hint how much memory should be allocated by the small vector

MutableLayerPtr

typedef std::shared_ptr< Layer > Acts::MutableLayerPtr = std::shared_ptr<Layer>

Type alias for a mutable pointer to a layer.

Used for non-const access to layer objects in the geometry

NavigationDelegate

using Acts::NavigationDelegate

Initial value:

 Delegate<void(
    const GeometryContext&, const NavigationArguments&, NavigationPolicyState&,
    AppendOnlyNavigationStream&, const Logger&)>

Central alias for the navigation delegate.

This type is owning to support (type-erased) navigation delegate chains (i.e. multiple policies).

NextLayers

using Acts::NextLayers = std::pair<const Layer*, const Layer*>

Type alias for adjacent layer pointers.

Stores pointers to the next inner and outer layers in the detector

ProjectorBitset

using Acts::ProjectorBitset = std::uint64_t

Type alias for bitset representing parameter projections.

Used to store parameter projection information in a compact bit format

ProxyAccessor

template<typename T>

using Acts::ProxyAccessor = ProxyAccessorBase<T, false>

Type alias for a mutable proxy accessor.

Provides mutable access to track state components through a proxy pattern

Template Parameters

T	The type of the component being accessed

Range1D

template<typename Type, template< typename, std::size_t > typename Vector = std::array>

using Acts::Range1D = RangeXD<1, Type, Vector>

Type alias for a one-dimensional range.

Specialization of RangeXD for one-dimensional ranges

Template Parameters

Type	The value type of the range
Vector	The container type template used to store the range bounds

Ray3D

using Acts::Ray3D = Ray<double, 3>

Type alias for a 3D ray using double precision.

Specialization of Ray class for three-dimensional space using double precision floating-point values

RecordedMaterialTrack

using Acts::RecordedMaterialTrack

Initial value:

 
    std::pair<std::pair<Acts::Vector3, Acts::Vector3>, RecordedMaterial>

And recorded material track.

• this is start: position, start momentum and the Recorded material

RecordedMaterialVolumePoint

using Acts::RecordedMaterialVolumePoint

Initial value:

 
    std::vector<std::pair<Acts::MaterialSlab, std::vector<Acts::Vector3>>>

list of point used in the mapping of a volume

RegularCylinderIndexGrid

using Acts::RegularCylinderIndexGrid

Initial value:

 
    Grid<std::vector<std::size_t>,
         Axis<AxisType::Equidistant, AxisBoundaryType::Closed>,
         Axis<AxisType::Equidistant, AxisBoundaryType::Bound>>

Regular cylinder grid in phi and z.

RegularCylinderIndexGridNavigationPolicy

using Acts::RegularCylinderIndexGridNavigationPolicy

Initial value:

 
    IndexGridNavigationPolicy<RegularCylinderIndexGrid>

Navigation policy for regular cylinder grids.

RegularDiscIndexGrid

using Acts::RegularDiscIndexGrid

Initial value:

 
    Grid<std::vector<std::size_t>,
         Axis<AxisType::Equidistant, AxisBoundaryType::Bound>,
         Axis<AxisType::Equidistant, AxisBoundaryType::Closed>>

Regular disc grid in r and phi.

RegularDiscIndexGridNavigationPolicy

using Acts::RegularDiscIndexGridNavigationPolicy

Initial value:

 
    IndexGridNavigationPolicy<RegularDiscIndexGrid>

Navigation policy for regular disc grids.

RegularPlaneIndexGrid

using Acts::RegularPlaneIndexGrid

Initial value:

 
    Grid<std::vector<std::size_t>,
         Axis<AxisType::Equidistant, AxisBoundaryType::Bound>,
         Axis<AxisType::Equidistant, AxisBoundaryType::Bound>>

Regular planar grid in x and y.

RegularPlaneIndexGridNavigationPolicy

using Acts::RegularPlaneIndexGridNavigationPolicy

Initial value:

 
    IndexGridNavigationPolicy<RegularPlaneIndexGrid>

Navigation policy for regular planar grids.

RegularRingIndexGrid

using Acts::RegularRingIndexGrid

Initial value:

 
    Grid<std::vector<std::size_t>,
         Axis<AxisType::Equidistant, AxisBoundaryType::Closed>>

Regular ring grid in phi.

RegularRingIndexGridNavigationPolicy

using Acts::RegularRingIndexGridNavigationPolicy

Initial value:

 
    IndexGridNavigationPolicy<RegularRingIndexGrid>

Navigation policy for regular ring grids.

SerializedSubspaceIndices

using Acts::SerializedSubspaceIndices = std::uint64_t

Type alias for serialized subspace indices.

Compact representation of subspace indices as a 64-bit unsigned integer

SurfaceMatcher

using Acts::SurfaceMatcher

Initial value:

 
    std::function<bool(const GeometryContext& gctx, AxisDirection,
                       const Surface*, const Surface*)>

Function type for comparing two surfaces in a given geometry context and axis direction.

Parameters

gctx	The geometry context for the comparison
dir	The axis direction to consider
s1	First surface to compare
s2	Second surface to compare

Returns

True if the surfaces are considered equivalent for binning purposes

SurfaceMaterialMaps

using Acts::SurfaceMaterialMaps

Initial value:

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

Type alias for surface material maps indexed by geometry identifier.

TrackingGeometryMaterial

using Acts::TrackingGeometryMaterial

Initial value:

 
    std::pair<SurfaceMaterialMaps, VolumeMaterialMaps>

Type alias for tracking geometry material containing surface and volume maps.

TrackingVolumeBoundaryPtr

using Acts::TrackingVolumeBoundaryPtr

Initial value:

 
    std::shared_ptr<const BoundarySurfaceT<TrackingVolume>>

Shared pointer to a constant BoundarySurfaceT of a TrackingVolume.

TrackingVolumeOrderPosition

using Acts::TrackingVolumeOrderPosition = std::pair<TrackingVolumePtr, Vector3>

A pair associating a tracking volume with its position vector.

Note

Used for ordering tracking volumes in a spatial array.

TrackingVolumePtr

typedef std::shared_ptr< const TrackingVolume > Acts::TrackingVolumePtr = std::shared_ptr<const TrackingVolume>

A std::shared_ptr to a tracking volume.

Interface types of the Gen1 geometry model.

Note

This interface is being replaced, and is subject to removal

TrackLinearizer

using Acts::TrackLinearizer

Initial value:

 Delegate<Result<LinearizedTrack>(
    const BoundTrackParameters& params, double linPointTime,
    const Surface& perigeeSurface, const GeometryContext& gctx,
    const MagneticFieldContext& mctx,
    MagneticFieldProvider::Cache& fieldCache)>

A delegate for linearizing a track at a given point in time and surface.

Note

Used for track fitting and vertexing.

VariableBoundSubspaceHelper

using Acts::VariableBoundSubspaceHelper

Initial value:

 
    VariableSubspaceHelper<Acts::eBoundSize, std::uint8_t>

Helper type for variable-size bound parameter subspaces.

Provides utilities for working with variable-size subspaces of bound track parameters.

VolumeMaterialMaps

using Acts::VolumeMaterialMaps

Initial value:

 
    std::map<GeometryIdentifier, std::shared_ptr<const IVolumeMaterial>>

Type alias for volume material maps indexed by geometry identifier.

Enumeration Type Documentation

AlignmentIndices

enum Acts::AlignmentIndices : unsigned int

Components of alignment parameters vector.

To be used to access components by named indices instead of just numbers. This must be a regular enum and not a scoped enum class to allow implicit conversion to an integer. The enum value are thus visible directly in namespace Acts and are prefixed to avoid naming collisions.

AxisBoundaryType

enum class Acts::AxisBoundaryType

strong

Enum which determines how the axis handle its outer boundaries possible values values.

Enumerator
Open	Default behaviour: out of bounds positions are filled into the over or underflow bins.
Bound	Out-of-bounds positions resolve to first/last bin respectively.
Closed	Out-of-bounds positions resolve to the outermost bin on the opposite side.

AxisDirection

enum class Acts::AxisDirection : int

strong

to specify a local axis direction

Enumerator
AxisX	AxisX, AxisY, AxisZ are the cartesian directions in the local frame.
AxisR	AxisR is a radial direction.
AxisPhi	AxisPhi is the azimuthal direction.
AxisRPhi	AxisRPhi is the radial-azimuthal direction.
AxisTheta	AxisTheta is the polar angle direction.
AxisEta	AxisEta is the pseudorapidity direction.
AxisMag	AxisMag is the magnitude of the vector.

AxisType

enum class Acts::AxisType

strong

Enum which determines the binning type of the axis.

Enumerator
Equidistant	An axis where all bins have the same size.
Variable	An axis where bins can have different sizes.

BinningType

enum Acts::BinningType

, BinningOption & BinningAccess

• BinningType:

  Enumeration to qualify the binning type for the use of the LayerArrayCreator and the TrackingVolumeArrayCreator

  • BinningOption: open: [0,max] closed: 0 -> nextbin -> max -> 0
  • AxisDirection necessary access to global positions

BoundarySurfaceFace

enum Acts::BoundarySurfaceFace

Enum to describe the position of the BoundarySurface respectively to the frame orientation of the volume, this is mainly meant for code readability.

The different numeration sequences can be found in the documentation of the actual VolumeBounds implementations.

The order of faces is chosen to follow - as much as possible - a circular structure.

BoundIndices

enum Acts::BoundIndices : unsigned int

Components of a bound track parameters vector.

To be used to access components by named indices instead of just numbers. This must be a regular enum and not a scoped enum class to allow implicit conversion to an integer. The enum value are thus visible directly in namespace Acts and are prefixed to avoid naming collisions.

CoordinateIndices

enum Acts::CoordinateIndices : unsigned int

Components of coordinate vectors.

To be used to access coordinate components by named indices instead of magic numbers. This must be a regular enum and not a scoped enum class to allow implicit conversion to an integer. The enum value are thus visible directly in namespace Acts.

This index enum is not user-configurable (in contrast e.g. to the track parameter index enums) since it must be compatible with varying dimensionality (2d-4d) and other access methods (.{x,y,z}() accessors).

FreeIndices

enum Acts::FreeIndices : unsigned int

Components of a free track parameters vector.

To be used to access components by named indices instead of just numbers. This must be a regular enum and not a scoped enum class to allow implicit conversion to an integer. The enum value are thus visible directly in namespace Acts and are prefixed to avoid naming collisions.

LinIndices

enum Acts::LinIndices : unsigned int

Enum to access the components of a track parameter vector.

Here, we parametrize the track via a 4D point on the track, the momentum angles of the particle at that point, and q/p or 1/p.

Note

It would make sense to rename these parameters if they are used outside of track linearization.

This must be a regular enum and not a scoped enum class to allow implicit conversion to an integer. The enum value are thus visible directly in namespace Acts and are prefixed to avoid naming collisions.

MaterialUpdateMode

enum class Acts::MaterialUpdateMode : std::uint8_t

strong

This is a steering enum to tell which material update mode:

• NoUpdate : no update
• PreUpdate : update on approach of a surface
• PostUpdate : update when leaving a surface
• FullUpdate : update when passing a surface

NoiseUpdateMode

enum class Acts::NoiseUpdateMode : int

strong

Steering enum to tell how to deal with the noise term in covariance transport:

• removeNoise: subtract noise term
• addNoise: add noise term

PortalMaterialMergePolicy

enum class Acts::PortalMaterialMergePolicy

strong

Policy controlling how Acts::Portal::merge treats surfaces that carry material.

Merged surfaces cannot retain the material of their inputs, so by default this is treated as a fatal error.

Enumerator
eThrow	Abort the merge by throwing a PortalMergingException (default).
eDiscardAndMark	Continue the merge: discard the input material, tag the merged surface with a MergedMaterialMarker and emit a warning. This is lossy.

PropagatorStage

enum class Acts::PropagatorStage

strong

Different stages during propagation.

Enumerator
invalid	Invalid stage.
prePropagation	Before the propagation.
postPropagation	After the propagation.
preStep	Before a step.
postStep	After a step.

SeedColumns

enum class Acts::SeedColumns : std::uint32_t

strong

Enumeration of available columns for space point data storage.

Enumerator
None	No columns.
SpacePointIndices	Indices of space points associated with the seed.
Quality	Quality of the seed.
VertexZ	Z coordinate of the vertex associated with.
All	All columns.

SpacePointColumns

enum class Acts::SpacePointColumns : std::uint32_t

strong

Enumeration of available columns for space point data storage.

Enumerator
None	No columns.
SourceLinks	Source link information.
CopiedFromIndex	Copied from index.
X	X coordinate.
Y	Y coordinate.
Z	Z coordinate.
R	Radial coordinate.
Phi	Azimuthal angle.
Time	Time coordinate.
VarianceZ	Variance of Z coordinate.
VarianceR	Variance of radial coordinate.
VarianceT	Variance of time coordinate.
StripCalibrationDetails	Calibration details for strip space points.
PackedXY	X and Y coordinates.
PackedZR	Z and R coordinates.
PackedXYZ	X, Y, and Z coordinates.
PackedXYZR	X, Y, Z, and R coordinates.
PackedVarianceZR	Variance in Z and R directions.
All	All columns.

TrackExtrapolationStrategy

enum class Acts::TrackExtrapolationStrategy

strong

Strategy for track extrapolation to target surface.

Enumerator
first	Use the first track state to reach target surface.
last	Use the last track state to reach target surface.
firstOrLast	Use the first or last track state to reach target surface depending on the distance.

TrackStateFlag

enum class Acts::TrackStateFlag

strong

Enumeration of track state flags.

The values define the bit positions in the underlying storage. The user may define custom flags starting from bit position NumFlags but it is recommended to start from bit position 16 or in reverse from 63 to avoid conflicts with future additions.

Enumerator
HasMeasurement	Indicates that the track state has an associated measurement. Note that an outlier also has a measurement.
HasParameters	Indicates that the track state has associated parameters.
IsOutlier	Indicates that the track state has an outlier measurement.
IsHole	Indicates that the track state has a hole (missing measurement).
HasMaterial	Indicates that the track state has associated material.
IsSharedHit	Indicates that the track state has a shared hit measurement.
IsSplitHit	Indicates that the track state has a split hit measurement.
HasNoExpectedHit	Indicates that the track state has no expected hit.
NumFlags	Number of defined flags.

TrackStatePropMask

enum struct Acts::TrackStatePropMask : std::uint8_t

strong

Collection of bit masks to enable steering which components of a track state should be initialized, and which should be left invalid.

These mask values can be combined using binary operators, so (TrackStatePropMask::Predicted | TrackStatePropMask::Jacobian) will instruct allocating storage for both predicted parameters (including covariance) and a jacobian. The enum is used as a strong type wrapper around the bits to prevent autoconversion from integer

VolumeAttachmentStrategy

enum class Acts::VolumeAttachmentStrategy

strong

The attachment strategy defines how the volumes are attached Attachment always happens pair-wise.

Enumerator
First	Given two volumes, the left one, i.e. the one with the lower local x, y, or z value is extended
Second	Given two volumes, the right one, i.e. the one with the higher local x, y, or z value is extended
Midpoint	Given two volumes, the midpoint between the two volumes is found.
Gap	A gap volume is created to fit between the two volumes.

VolumeResizeStrategy

enum class Acts::VolumeResizeStrategy

strong

The resize strategy defines how the volumes are resized.

Enumerator
Expand	Extend the volume connected to the respective edge to fit the new bounds.
Gap	Create a gap volume at the respective edge to fit the new bounds.

WrappingCondition

enum Acts::WrappingCondition

Volume wrapping conditions for cylinder volume building.

Enumerator
Undefined	inconsistency detected
Attaching	attach the volumes
Inserting	insert the new volume
Wrapping	wrap the new volume around
CentralInserting	insert the new one into the center
CentralWrapping	wrap the new central volume around
NoWrapping	no inner volume present - no wrapping needed

Function Documentation

abs()

template<typename T>

T Acts::abs ( const T n )

constexpr

Returns the absolute of a number.

Note

Can be removed for C++23

Parameters

n	The number to take absolute value of

Returns

The absolute value of the input

addBoundParameters()

BoundVector Acts::addBoundParameters	(	const BoundVector &	lhs,
		const BoundVector &	rhs )

Add bound parameters and take care of angle periodicity for phi and theta.

This is intended for small differences only i.e. KF updates.

Parameters

lhs	The left hand side bound parameters
rhs	The right hand side bound parameters

Returns

The sum of the bound parameters

adjustBinUtility() [1/9]

BinUtility Acts::adjustBinUtility	(	const BinUtility &	bu,
		const CuboidVolumeBounds &	cBounds,
		const Transform3 &	transform )

adjust the BinUtility bu to the dimensions of cuboid volume bounds

Parameters

bu	BinUtility at source
cBounds	the Cuboid volume bounds to adjust to
transform	Transform for the adjusted BinUtility

Returns

new updated BinUtiltiy

adjustBinUtility() [2/9]

BinUtility Acts::adjustBinUtility	(	const BinUtility &	bu,
		const CutoutCylinderVolumeBounds &	cBounds,
		const Transform3 &	transform )

adjust the BinUtility bu to the dimensions of cutout cylinder volume bounds

Parameters

bu	BinUtility at source
cBounds	the Cutout Cylinder volume bounds to adjust to
transform	Transform for the adjusted BinUtility

Returns

new updated BinUtiltiy

adjustBinUtility() [3/9]

BinUtility Acts::adjustBinUtility ( const BinUtility & bu, const CylinderBounds & cBounds, const Transform3 & transform )

static

adjust the BinUtility bu to the dimensions of cylinder bounds

Parameters

bu	BinUtility at source
cBounds	the Cylinder bounds to adjust to
transform	Transform for the adjusted BinUtility

Returns

new updated BinUtiltiy

adjustBinUtility() [4/9]

BinUtility Acts::adjustBinUtility	(	const BinUtility &	bu,
		const CylinderVolumeBounds &	cBounds,
		const Transform3 &	transform )

adjust the BinUtility bu to the dimensions of cylinder volume bounds

Parameters

bu	BinUtility at source
cBounds	the Cylinder volume bounds to adjust to
transform	Transform for the adjusted BinUtility

Returns

new updated BinUtiltiy

adjustBinUtility() [5/9]

BinUtility Acts::adjustBinUtility ( const BinUtility & bu, const RadialBounds & rBounds, const Transform3 & transform )

static

adjust the BinUtility bu to the dimensions of radial bounds

Parameters

bu	BinUtility at source
rBounds	the Radial bounds to adjust to
transform	Transform for the adjusted BinUtility

Returns

new updated BinUtiltiy

adjustBinUtility() [6/9]

BinUtility Acts::adjustBinUtility ( const BinUtility & bu, const RectangleBounds & pBounds, const Transform3 & transform )

static

adjust the BinUtility bu to the dimensions of plane bounds

Parameters

bu	BinUtility at source
pBounds	the Rectangle bounds to adjust to
transform	Transform for the adjusted BinUtility

Returns

new updated BinUtiltiy

adjustBinUtility() [7/9]

BinUtility Acts::adjustBinUtility ( const BinUtility & bu, const Surface & surface, const GeometryContext & gctx )

static

adjust the BinUtility bu to a surface

Parameters

bu	BinUtility at source
surface	Surface to which the adjustment is being done
gctx	Geometry context to get the surfaces transform

Returns

new updated BinUtiltiy

adjustBinUtility() [8/9]

BinUtility Acts::adjustBinUtility ( const BinUtility & bu, const TrapezoidBounds & pBounds, const Transform3 & transform )

static

adjust the BinUtility bu to the dimensions of plane bounds

Parameters

bu	BinUtility at source
pBounds	the Trapezoid bounds to adjust to
transform	Transform for the adjusted BinUtility

Returns

new updated BinUtiltiy

adjustBinUtility() [9/9]

BinUtility Acts::adjustBinUtility	(	const GeometryContext &	gctx,
		const BinUtility &	bu,
		const Volume &	volume )

adjust the BinUtility bu to a volume

Parameters

gctx	The current geometry context object, e.g. alignment
bu	BinUtility at source
volume	Volume to which the adjustment is being done

Returns

new updated BinUtiltiy

allAxisDirections()

const std::vector< AxisDirection > & Acts::allAxisDirections

(

)

Get all possible axis directions.

Returns

a vector of all possible axis directions

AnyGridConstView()

template<typename T, typename... Axes>

Acts::AnyGridConstView

(

const Grid< T, Axes... > &

grid

)

->AnyGridConstView< T >

Deduction guide for AnyGridConstView from const Grid.

Template Parameters

T	Type of values stored in the grid
Axes	Parameter pack of axis types defining the grid

Parameters

grid	The const grid to create a view for

AnyGridView()

template<typename T, typename... Axes>

Acts::AnyGridView

(

Grid< T, Axes... > &

grid

)

->AnyGridView< T >

Deduction guide for AnyGridView from Grid.

Template Parameters

T	Type of values stored in the grid
Axes	Parameter pack of axis types defining the grid

Parameters

grid	The grid to create a view for

applyReferenceExpansion()

template<typename grid_type>

void Acts::applyReferenceExpansion	(	std::vector< typename grid_type::point_t > &	gridQueries,
		const std::vector< double > &	referenceExpansion )

Run the reference expansion.

Template Parameters

grid_type

the type of the grid

Parameters

gridQueries	the grid queries to be expanded
referenceExpansion	the reference expansion values

approximateHighlandScattering()

float Acts::approximateHighlandScattering

(

float

xOverX0

)

Approximate the core width of the projected planar scattering distribution with Highland's formula.

In contrast to computeMultipleScatteringTheta0, this ignores the particle charge and velocity (assuming a singly-charged, ultra-relativistic particle with \(q^2/\beta^2 = 1\)) and does not divide by the momentum. It therefore returns \(\theta_0 \cdot p\) rather than \(\theta_0\) itself, which is convenient when the momentum is not yet known.

Parameters

xOverX0

The thickness of the material in radiation lengths

Returns

The projected scattering angle scaled by momentum, \(\theta_0 \cdot p\), in native units (radians times momentum)

axesDirectionName()

std::string Acts::axesDirectionName

(

const std::vector< AxisDirection > &

manyDir

)

Get the name of a vector of binning values as a string.

Parameters

manyDir

is the vector of binning values

Returns

the name of the binning value

Axis() [1/4]

template<AxisBoundaryType bdt>

Acts::Axis	(	AxisBoundaryTypeTag< bdt >	,
		double	min,
		double	max,
		std::size_t	bins )->Axis< AxisType::Equidistant, bdt >

Deduction guide for equidistant axis with specified boundary type.

Parameters

min	Minimum value
max	Maximum value
bins	Number of bins

Axis() [2/4]

template<AxisBoundaryType bdt>

Acts::Axis	(	AxisBoundaryTypeTag< bdt >	,
		std::vector< double >	bins )->Axis< AxisType::Variable, bdt >

Deduction guide for variable axis with specified boundary type.

Parameters

bins	Vector of bin edges

Axis() [3/4]

Acts::Axis	(	double	min,
		double	max,
		std::size_t	bins )->Axis< AxisType::Equidistant, AxisBoundaryType::Open >

Deduction guide for equidistant axis with open boundaries.

Parameters

min	Minimum value
max	Maximum value
bins	Number of bins

Axis() [4/4]

Acts::Axis

(

std::vector< double >

bins

)

->Axis< AxisType::Variable, AxisBoundaryType::Open >

Deduction guide for variable axis with open boundaries.

Parameters

bins	Vector of bin edges

axisDirectionFromName()

AxisDirection Acts::axisDirectionFromName

(

const std::string &

name

)

Get an axis direction from its string name.

Parameters

name	is the name of the axis direction

Returns

the axis direction

axisDirectionName()

const std::string & Acts::axisDirectionName

(

AxisDirection

aDir

)

Get the name of a binning value as a string.

Parameters

aDir	is the binning value

Returns

the name of the binning value

binomial()

template<std::unsigned_integral T>

T Acts::binomial ( const T n, const T k )

constexpr

Calculate the binomial coefficient n n!

= -----— k k!(n-k)!

Parameters

n	Upper value in binomial coefficient
k	Lower value in binomial coefficient

Returns

Binomial coefficient n choose k

binSequence()

std::vector< std::size_t > Acts::binSequence	(	std::array< std::size_t, 2u >	minMaxBins,
		std::size_t	expand,
		std::size_t	nBins,
		Acts::AxisBoundaryType	type )

Helper method to generate completely populated bin sequences that respect the boundary type of the axis.

Parameters

minMaxBins	estimated bin range (aka binning boundary box)
expand	the parameter to expand the view (extra window)
nBins	the maximum number of bins on this axis
type	the boundary type of the axis (for correct bin closure)

Note

for closed binning a span over half the bins flips direction

Returns

a vector of bins to be filled

bitsetToMatrix()

template<typename MatrixType>

MatrixType Acts::bitsetToMatrix

(

const std::bitset< MatrixType::RowsAtCompileTime *MatrixType::ColsAtCompileTime >

bs

)

Convert a bitset to a matrix of integers, with each element set to the bit value.

Note

How the bits are assigned to matrix elements depends on the storage type of the matrix being converted (row-major or col-major)

Template Parameters

MatrixType

Matrix type that is produced

Parameters

bs	The bitset to convert

Returns

A matrix with the integer values of the bits from bs

blockedMult()

template<typename A, typename B>

Matrix< A::RowsAtCompileTime, B::ColsAtCompileTime > Acts::blockedMult	(	const A &	a,
		const B &	b )

Perform a blocked matrix multiplication, avoiding Eigen GEMM methods.

Template Parameters

A	The type of the first matrix, which should be MxN
B	The type of the second matrix, which should be NxP

Parameters

[in]	a	An MxN matrix of type A
[in]	b	An NxP matrix of type P

Returns

The product ab

calculateFilteredChi2()

template<TrackStateProxyConcept track_state_proxy_t>

double Acts::calculateFilteredChi2

(

track_state_proxy_t

trackState

)

Helper function to calculate the filtered chi2.

Template Parameters

track_state_proxy_t

the track state proxy type

Parameters

trackState

the track state to calculate the chi2 from

Returns

the chi2

calculateFilteredResidual()

template<std::size_t nMeasurementDim, TrackStateProxyConcept track_state_proxy_t>

std::pair< Vector< nMeasurementDim >, SquareMatrix< nMeasurementDim > > Acts::calculateFilteredResidual

(

track_state_proxy_t

trackState

)

Helper function to calculate the filtered residual and its covariance.

Template Parameters

nMeasurementDim	the dimension of the measurement
track_state_proxy_t	the track state proxy type

Parameters

trackState

the track state to calculate the residual from

Returns

a pair of the residual and its covariance

calculateNucleusMass()

float Acts::calculateNucleusMass

(

PdgParticle

pdg

)

Calculate the mass of a nucleus using Bethe-Weizsacker formula Parameters obtained from https://www.actaphys.uj.edu.pl/index_n.php?I=R&V=37&N=6#1833.

Parameters

pdg	PDG particle number for the nucleus

Returns

Mass in native units

calculatePredictedChi2()

template<TrackStateProxyConcept track_state_proxy_t>

double Acts::calculatePredictedChi2

(

track_state_proxy_t

trackState

)

Helper function to calculate the predicted chi2.

Template Parameters

track_state_proxy_t

the track state proxy type

Parameters

trackState

the track state to calculate the chi2 from

Returns

the chi2

calculatePredictedResidual()

template<std::size_t nMeasurementDim, TrackStateProxyConcept track_state_proxy_t>

std::pair< Vector< nMeasurementDim >, SquareMatrix< nMeasurementDim > > Acts::calculatePredictedResidual

(

track_state_proxy_t

trackState

)

Helper function to calculate the predicted residual and its covariance.

Template Parameters

nMeasurementDim	the dimension of the measurement
track_state_proxy_t	the track state proxy type

Parameters

trackState

the track state to calculate the residual from

Returns

a pair of the residual and its covariance

calculateSmoothedChi2()

template<TrackStateProxyConcept track_state_proxy_t>

double Acts::calculateSmoothedChi2

(

track_state_proxy_t

trackState

)

Helper function to calculate the smoothed chi2.

Template Parameters

track_state_proxy_t

the track state proxy type

Parameters

trackState

the track state to calculate the chi2 from

Returns

the chi2

calculateSmoothedResidual()

template<std::size_t nMeasurementDim, TrackStateProxyConcept track_state_proxy_t>

std::pair< Vector< nMeasurementDim >, SquareMatrix< nMeasurementDim > > Acts::calculateSmoothedResidual

(

track_state_proxy_t

trackState

)

Helper function to calculate the smoothed residual and its covariance.

Template Parameters

nMeasurementDim	the dimension of the measurement
track_state_proxy_t	the track state proxy type

Parameters

trackState

the track state to calculate the residual from

Returns

a pair of the residual and its covariance

calculateTrackQuantities()

template<TrackProxyConcept track_proxy_t>
requires (!track_proxy_t::ReadOnly)

void Acts::calculateTrackQuantities

(

track_proxy_t

track

)

Helper function to calculate a number of track level quantities and store them on the track itself.

Template Parameters

track_proxy_t

The track proxy type

Parameters

track

A mutable track proxy to operate on

calculateUnbiasedParametersCovariance() [1/2]

std::pair< BoundVector, BoundMatrix > Acts::calculateUnbiasedParametersCovariance

(

const AnyConstTrackStateProxy &

trackState

)

Calculate the unbiased track parameters and their covariance for a type-erased track state proxy.

See the templated overload above for the underlying formula.

This is the preferred entry point. It is not a template, so the (very expensive) Eigen expression templates are instantiated exactly once, in the Acts core library (TrackHelpersUnbiased.cpp), instead of in every calling translation unit. Callers holding a concrete track state proxy wrap it:

calculateUnbiasedParametersCovariance(Acts::AnyConstTrackStateProxy{state});

Parameters

trackState

the (type-erased) track state to calculate from

Returns

a pair of the unbiased parameters and their covariance

calculateUnbiasedParametersCovariance() [2/2]

template<TrackStateProxyConcept track_state_proxy_t>

std::pair< BoundVector, BoundMatrix > Acts::calculateUnbiasedParametersCovariance

(

track_state_proxy_t

trackState

)

Helper function to calculate the unbiased track parameters and their covariance (i.e.

fitted track parameters with this measurement removed) using Eq.(12a)-Eq.(12c) of NIMA 262, 444 (1987)

Template Parameters

track_state_proxy_t

the track state proxy type

Parameters

trackState

the track state to calculate the unbiased parameters from

Returns

a pair of the unbiased parameters and their covariance

Deprecated

Instantiating this template is very expensive in compiler memory (it expands the Eigen expression templates over all measurement dimensions) and it does so in every calling translation unit. Prefer the non-template overload taking a type-erased AnyConstTrackStateProxy, which is compiled once in the Acts core library:

calculateUnbiasedParametersCovariance(Acts::AnyConstTrackStateProxy{state});

calibrateOuterStripSpacePoint()

Eigen::Vector3f Acts::calibrateOuterStripSpacePoint	(	const Eigen::Vector3f &	direction,
		const OuterStripSpacePointCalibrationDetailsDerived &	sp )

Calibrates the strip space point using the assumed particle direction and the strip space point calibration details.

Note

This function does not check if the calibrated space point lies within the strip.

Parameters

sp	The strip space point calibration details
direction	The assumed particle direction

Returns

The calibrated outer strip space point

cathetusSquare()

template<typename T, typename... Args>

auto Acts::cathetusSquare ( T hypotenuse, Args... args )

constexpr

Calculates the squared cathetus of arguments, i.e.

the difference between the square of the hypotenuse and the square of the given arguments.

Parameters

hypotenuse	The hypotenuse value
args	Variable number of arguments to calculate the cathetus for

Returns

Difference between the square of the hypotenuse and the square of the given arguments. Returns NaN for floating point types if the hypotenuse is smaller than the cathetus.

Exceptions

std::domain_error

if hypotenuse is smaller than the cathetus for integral types

cathetusSquareUnchecked()

template<typename T, typename... Args>

auto Acts::cathetusSquareUnchecked ( T hypotenuse, Args... args )

constexpr

Calculates the squared cathetus of arguments, i.e.

the difference between the square of the hypotenuse and the square of the given arguments without checking for domain errors.

Parameters

hypotenuse	The hypotenuse value
args	Variable number of arguments to calculate the cathetus for

Returns

Difference between the square of the hypotenuse and the square of the given arguments

checkSubspaceIndices()

template<std::ranges::sized_range index_range_t>

bool Acts::checkSubspaceIndices ( const index_range_t & indexRange, std::size_t fullSize, std::size_t subspaceSize )

static

Check subspace indices for consistency.

Indices must be unique and within the full size of the subspace

Template Parameters

index_range_t

the type of the container of indices

Parameters

indexRange	the range of indices
fullSize	the full size of the subspace
subspaceSize	the size of the subspace

Returns

true if the indices are consistent

clampValue()

template<typename T, typename U>

T Acts::clampValue

(

U

value

)

Clamp a numeric value to another type, respecting range of the target type.

Template Parameters

T	the target type
U	the source type

Parameters

value

the value to clamp

Returns

the clamped value

compose()

template<typename... Fs>

auto Acts::compose

(

Fs &&...

fs

)

Compose multiple callables into a single callable, applied right-to-left (mathematical convention).

Given compose(f, g, h), the returned callable computes f(g(h(x))). All callables are stored exactly once in a tuple, avoiding the nested-copy overhead of a recursive lambda approach.

Template Parameters

Fs	The callable types

Parameters

fs	The callables to compose

Returns

A callable that applies fs right-to-left

computeEnergyLossBethe()

float Acts::computeEnergyLossBethe	(	const MaterialSlab &	slab,
		float	m,
		float	qOverP,
		float	absQ )

Compute the mean energy loss due to ionisation and excitation.

Parameters

slab	The traversed material and its properties
m	Particle mass
qOverP	Particle charge divided by absolute momentum
absQ	Absolute particle charge

This computes the mean ionisation energy loss \(-dE(x)\) of a particle traversing the material slab,

\[ -dE(x) = -\frac{dE}{dx}\, x, \]

where \(-dE/dx\) is given by the Bethe formula [9] (eq. 33.5), including the density-effect correction. The result is the magnitude of the loss (always \(\geq 0\)); The formula is valid for intermediate energies, roughly \(0.1 \lesssim \beta\gamma \lesssim 1000\).

Returns

Mean ionisation energy loss through the slab in native energy units

See also

computeEnergyLossLandau for the most probable value, computeEnergyLossRadiative for radiative losses, and computeEnergyLossMean for the sum of both

computeEnergyLossLandau()

float Acts::computeEnergyLossLandau	(	const MaterialSlab &	slab,
		float	m,
		float	qOverP,
		float	absQ )

Compute the most probable energy loss due to ionisation and excitation.

Parameters

slab	The traversed material and its properties
m	Particle mass
qOverP	Particle charge divided by absolute momentum
absQ	Absolute particle charge

This computes the most probable ionisation energy loss \(-dE(x)\) through the material slab, i.e. the mode of the Landau-Vavilov-Bichsel distribution [9] (eq. 33.12), including the density-effect correction. Unlike computeEnergyLossBethe (which returns the mean), this is the most probable value, which for thin slabs is noticeably smaller than the mean because of the long tail of the distribution. The formula is valid for intermediate energies, roughly \(0.1 \lesssim \beta\gamma \lesssim 1000\).

Returns

Most probable ionisation energy loss through the slab in native energy units

computeEnergyLossLandauFwhm()

float Acts::computeEnergyLossLandauFwhm	(	const MaterialSlab &	slab,
		float	m,
		float	qOverP,
		float	absQ )

Compute the full with half maximum of landau energy loss distribution.

Parameters

slab	The traversed material and its properties
m	Particle mass
qOverP	Particle charge divided by absolute momentum
absQ	Absolute particle charge

Returns

Full width half maximum of the Landau distribution

computeEnergyLossLandauSigma()

float Acts::computeEnergyLossLandauSigma	(	const MaterialSlab &	slab,
		float	m,
		float	qOverP,
		float	absQ )

Compute the Gaussian-equivalent sigma for the ionisation loss fluctuations.

See also

computeEnergyLossBethe for parameters description

This is the sigma parameter of a Gaussian distribution with the same full-width-half-maximum as the Landau-Vavilov-Bichsel distribution. The computations are valid for intermediate particle energies.

Parameters

slab	The traversed material and its properties
m	Particle mass
qOverP	Particle charge divided by absolute momentum
absQ	Absolute particle charge

Returns

Gaussian-equivalent sigma for energy loss fluctuations

computeEnergyLossLandauSigmaQOverP()

float Acts::computeEnergyLossLandauSigmaQOverP	(	const MaterialSlab &	slab,
		float	m,
		float	qOverP,
		float	absQ )

Compute the Gaussian-equivalent sigma of q/p due to ionisation fluctuations.

Parameters

slab	The traversed material and its properties
m	Particle mass
qOverP	Particle charge divided by absolute momentum
absQ	Absolute particle charge

This propagates the energy-loss straggling (the Gaussian-equivalent sigma \(\sigma_E\) from computeEnergyLossLandauSigma) into a standard deviation on \(q/p\) using the Jacobian \(d(q/p)/dE\),

\[ \sigma_{q/p} = \left|\frac{d(q/p)}{dE}\right|\, \sigma_E . \]

This is the quantity used as the \(q/p\) process noise in the Kalman fitters.

Returns

Gaussian-equivalent standard deviation of q/p

computeEnergyLossMean()

float Acts::computeEnergyLossMean	(	const MaterialSlab &	slab,
		PdgParticle	absPdg,
		float	m,
		float	qOverP,
		float	absQ )

Compute the combined mean energy loss.

Parameters

slab	The traversed material and its properties
absPdg	Absolute particle type PDG identifier
m	Particle mass
qOverP	Particle charge divided by absolute momentum
absQ	Absolute particle charge

This computes the combined mean energy loss -dE(x) including ionisation and radiative effects. The computations are valid over a wide range of particle energies.

Returns

Combined mean energy loss through the material slab

computeEnergyLossMode()

float Acts::computeEnergyLossMode	(	const MaterialSlab &	slab,
		PdgParticle	absPdg,
		float	m,
		float	qOverP,
		float	absQ )

Compute the combined most probably energy loss.

Compute the combined mean energy loss.

Parameters

slab	The traversed material and its properties
absPdg	Absolute particle type PDG identifier
m	Particle mass
qOverP	Particle charge divided by absolute momentum
absQ	Absolute particle charge

This computes the combined mean energy loss -dE(x) including ionisation and radiative effects. The computations are valid over a wide range of particle energies.

Returns

Combined mean energy loss through the material slab

Combined most probable energy loss through the material slab

computeEnergyLossRadiative()

float Acts::computeEnergyLossRadiative	(	const MaterialSlab &	slab,
		PdgParticle	absPdg,
		float	m,
		float	qOverP,
		float	absQ )

Compute the mean energy loss due to radiative effects at high energies.

Parameters

slab	The traversed material and its properties
absPdg	Absolute particle type PDG identifier
m	Particle mass
qOverP	Particle charge divided by absolute momentum
absQ	Absolute particle charge

This computes the mean radiative energy loss \(-dE(x)\) using the approximation of [6]. Bremsstrahlung, scaling with \((m_e/m)^2\), is always included; direct \(e^+e^-\) pair production and photo-nuclear interactions are added only for muons above \(8\,\mathrm{GeV}\). Like computeEnergyLossBethe the result is the magnitude of the loss (always \(\geq 0\)).

Returns

Mean radiative energy loss through the slab in native energy units

computeMultipleScatteringTheta0()

float Acts::computeMultipleScatteringTheta0	(	const MaterialSlab &	slab,
		PdgParticle	absPdg,
		float	m,
		float	qOverP,
		float	absQ )

Compute the core width of the projected planar scattering distribution.

Parameters

slab	The traversed material and its properties
absPdg	Absolute particle type PDG identifier
m	Particle mass
qOverP	Particle charge divided by absolute momentum
absQ	Absolute particle charge

The returned \(\theta_0\) is the standard deviation of the central (Gaussian) part of the multiple-Coulomb-scattering angle, projected onto a plane. For all particles except electrons and positrons it is evaluated with the Highland formula [5] in the parametrisation of [9] (eq. 33.15); for electrons and positrons the Rossi-Greisen form is used instead.

Note

This is the projected (single-plane) width; the width of the polar space angle is larger by a factor \(\sqrt{2}\).

Returns

Projected scattering angle standard deviation \(\theta_0\) in radians

See also

approximateHighlandScattering for a charge- and momentum-independent approximation

copySign()

template<typename out_t, typename sign_t>

out_t Acts::copySign ( const out_t & copyTo, const sign_t & sign )

constexpr

Copies the sign of a signed variable onto the copyTo input object.

Return type & magnitude remain unaffected by this method which allows usage for Vectors & other types providing the - operator. By convention, the zero is assigned to a positive sign.

Parameters

copyTo	Variable to which the sign is copied to.
sign	Variable from which the sign is taken.

Returns

The copyTo variable with the sign of the sign parameter

createCurvilinearUnitU()

template<typename InputVector>

auto Acts::createCurvilinearUnitU

(

const Eigen::MatrixBase< InputVector > &

direction

)

Construct the first curvilinear unit vector U for the given direction.

Parameters

direction

is the input direction vector

Returns

a normalized vector in the x-y plane orthogonal to the direction.

The special case of the direction vector pointing along the z-axis is handled by forcing the unit vector to along the x-axis.

createCurvilinearUnitVectors()

template<typename InputVector>

auto Acts::createCurvilinearUnitVectors

(

const Eigen::MatrixBase< InputVector > &

direction

)

Construct the curvilinear unit vectors U and V for the given direction.

Parameters

direction

is the input direction vector

Returns

normalized unit vectors U and V orthogonal to the direction.

With T the normalized input direction, the three vectors U, V, and T form an orthonormal basis set, i.e. they satisfy

U x V = T
V x T = U
T x U = V

with the additional condition that U is located in the global x-y plane.

createGrid() [1/2]

Grid2D Acts::createGrid	(	MaterialGridAxisData	gridAxis1,
		MaterialGridAxisData	gridAxis2 )

Helper method that creates the cache grid for the mapping.

This grid allows the collection of material at a the anchor points.

Parameters

[in]	gridAxis1	Axis data
[in]	gridAxis2	Axis data

Note

The data of the axes is given in the std::array as {minimum value, maximum value, number of bins}

Returns

The grid

createGrid() [2/2]

Grid3D Acts::createGrid	(	MaterialGridAxisData	gridAxis1,
		MaterialGridAxisData	gridAxis2,
		MaterialGridAxisData	gridAxis3 )

Helper method that creates the cache grid for the mapping.

This grid allows the collection of material at a the anchor points.

Parameters

[in]	gridAxis1	Axis data
[in]	gridAxis2	Axis data
[in]	gridAxis3	Axis data

Note

The data of the axes is given in the std::array as {minimum value, maximum value, number of bins}

Returns

The grid

createGrid2D()

Grid2D Acts::createGrid2D	(	const BinUtility &	bins,
		std::function< Acts::Vector2(Acts::Vector3)> &	transfoGlobalToLocal )

Create a 2DGrid using a BinUtility.

Also determine the corresponding global to local transform and grid mapping function

Parameters

[in]	bins	BinUtility of the volume to be mapped
[in]	transfoGlobalToLocal	Global to local transform to be updated.

Returns

the 3D grid

createGrid3D()

Grid3D Acts::createGrid3D	(	const BinUtility &	bins,
		std::function< Acts::Vector3(Acts::Vector3)> &	transfoGlobalToLocal )

Create a 3DGrid using a BinUtility.

Also determine the corresponding global to local transform and grid mapping function

Parameters

[in]	bins	BinUtility of the volume to be mapped
[in]	transfoGlobalToLocal	Global to local transform to be updated.

Returns

the 3D grid

deriveEnergyLossBetheQOverP()

float Acts::deriveEnergyLossBetheQOverP	(	const MaterialSlab &	slab,
		float	m,
		float	qOverP,
		float	absQ )

Derivative of the Bethe energy loss with respect to q/p.

Compute the mean energy loss due to ionisation and excitation.

Parameters

slab	The traversed material and its properties
m	Particle mass
qOverP	Particle charge divided by absolute momentum
absQ	Absolute particle charge

This computes the mean ionisation energy loss \(-dE(x)\) of a particle traversing the material slab,

\[ -dE(x) = -\frac{dE}{dx}\, x, \]

where \(-dE/dx\) is given by the Bethe formula [9] (eq. 33.5), including the density-effect correction. The result is the magnitude of the loss (always \(\geq 0\)); The formula is valid for intermediate energies, roughly \(0.1 \lesssim \beta\gamma \lesssim 1000\).

Returns

Mean ionisation energy loss through the slab in native energy units

See also

computeEnergyLossLandau for the most probable value, computeEnergyLossRadiative for radiative losses, and computeEnergyLossMean for the sum of both

Returns

Derivative of the mean ionisation energy loss with respect to q/p

deriveEnergyLossLandauQOverP()

float Acts::deriveEnergyLossLandauQOverP	(	const MaterialSlab &	slab,
		float	m,
		float	qOverP,
		float	absQ )

Derivative of the most probable ionisation energy loss with respect to q/p.

Compute the most probable energy loss due to ionisation and excitation.

Parameters

slab	The traversed material and its properties
m	Particle mass
qOverP	Particle charge divided by absolute momentum
absQ	Absolute particle charge

This computes the most probable ionisation energy loss \(-dE(x)\) through the material slab, i.e. the mode of the Landau-Vavilov-Bichsel distribution [9] (eq. 33.12), including the density-effect correction. Unlike computeEnergyLossBethe (which returns the mean), this is the most probable value, which for thin slabs is noticeably smaller than the mean because of the long tail of the distribution. The formula is valid for intermediate energies, roughly \(0.1 \lesssim \beta\gamma \lesssim 1000\).

Returns

Most probable ionisation energy loss through the slab in native energy units

Derivative of the most probable ionisation energy loss with respect to q/p

deriveEnergyLossMeanQOverP()

float Acts::deriveEnergyLossMeanQOverP	(	const MaterialSlab &	slab,
		PdgParticle	absPdg,
		float	m,
		float	qOverP,
		float	absQ )

Derivative of the combined mean energy loss with respect to q/p.

Compute the combined mean energy loss.

Parameters

slab	The traversed material and its properties
absPdg	Absolute particle type PDG identifier
m	Particle mass
qOverP	Particle charge divided by absolute momentum
absQ	Absolute particle charge

This computes the combined mean energy loss -dE(x) including ionisation and radiative effects. The computations are valid over a wide range of particle energies.

Returns

Combined mean energy loss through the material slab

Derivative of combined mean energy loss with respect to q/p

deriveEnergyLossModeQOverP()

float Acts::deriveEnergyLossModeQOverP	(	const MaterialSlab &	slab,
		PdgParticle	absPdg,
		float	m,
		float	qOverP,
		float	absQ )

Derivative of the combined most probable energy loss with respect to q/p.

Compute the combined mean energy loss.

Parameters

slab	The traversed material and its properties
absPdg	Absolute particle type PDG identifier
m	Particle mass
qOverP	Particle charge divided by absolute momentum
absQ	Absolute particle charge

This computes the combined mean energy loss -dE(x) including ionisation and radiative effects. The computations are valid over a wide range of particle energies.

Returns

Combined mean energy loss through the material slab

Derivative of combined most probable energy loss with respect to q/p

deriveEnergyLossRadiativeQOverP()

float Acts::deriveEnergyLossRadiativeQOverP	(	const MaterialSlab &	slab,
		PdgParticle	absPdg,
		float	m,
		float	qOverP,
		float	absQ )

Derivative of the mean radiative energy loss with respect to q/p.

Compute the mean energy loss due to radiative effects at high energies.

Parameters

slab	The traversed material and its properties
absPdg	Absolute particle type PDG identifier
m	Particle mass
qOverP	Particle charge divided by absolute momentum
absQ	Absolute particle charge

This computes the mean radiative energy loss \(-dE(x)\) using the approximation of [6]. Bremsstrahlung, scaling with \((m_e/m)^2\), is always included; direct \(e^+e^-\) pair production and photo-nuclear interactions are added only for muons above \(8\,\mathrm{GeV}\). Like computeEnergyLossBethe the result is the magnitude of the loss (always \(\geq 0\)).

Returns

Mean radiative energy loss through the slab in native energy units

Derivative of radiative energy loss with respect to q/p

deriveOuterStripSpacePointCalibrationDetails()

OuterStripSpacePointCalibrationDetailsDerived Acts::deriveOuterStripSpacePointCalibrationDetails

(

const OuterStripSpacePointCalibrationDetails &

sp

)

Derives the strip space point calibration details.

Parameters

sp	The strip space point calibration details

Returns

The derived strip space point calibration details

deserializeSubspaceIndices()

template<std::size_t FullSize>
requires (FullSize <= 8)

SubspaceIndices< FullSize > Acts::deserializeSubspaceIndices ( SerializedSubspaceIndices serialized )

static

Deserialize subspace indices from a single 64 bit integer.

Template Parameters

FullSize

the full size of the subspace

Parameters

serialized

the serialized subspace indices

Returns

the subspace indices

enumerate()

template<std::ranges::range container_type, typename index_type = typename detail::EnumerateIndexType<container_type>::type, typename container_type_iter = decltype(std::begin(std::declval<container_type>()))>

auto Acts::enumerate ( container_type && iterable )

constexpr

Helper utility to allow indexed enumeration with structured binding.

Usage:

for (auto [ i, value ] : enumerate(container) ) { ... };

with 'container' any stl-like container

Parameters

iterable

Container to enumerate

Returns

Enumerable wrapper with index and value pairs

expand()

template<typename queries_type, typename expansion_type, std::size_t kDIM>

void Acts::expand	(	queries_type &	gridQueries,
		const expansion_type &	referenceExpansion )

Helper method to expand the grid queries along a given dimension.

Template Parameters

queries_type	the type of the grid queries
expansion_type	the type of the reference expansion
kDIM	the dimension to be expanded

Parameters

gridQueries	the grid queries to be expanded
referenceExpansion	the reference expansion values

extractNucleusZandA()

constexpr std::pair< std::int32_t, std::int32_t > Acts::extractNucleusZandA ( PdgParticle pdg )

staticconstexpr

Extract Z and A for a given nucleus.

PDG number of a nucleus has a form 10LZZZAAAI, where L is number of lambdas, ZZZ is proton number, AAA is atomic number, I is isomer level. See PDG section "Monte Carlo Particle Numbering Scheme" , point 16: https://pdg.lbl.gov/2025/reviews/rpp2024-rev-monte-carlo-numbering.pdf

Parameters

pdg	The PDG particle code of the nucleus

Returns

A pair containing the proton number (Z) and atomic number (A)

extrapolateTracksToReferenceSurface()

template<TrackContainerFrontend track_container_t, typename propagator_t, typename propagator_options_t>

Result< void > Acts::extrapolateTracksToReferenceSurface	(	const track_container_t &	trackContainer,
		const Surface &	referenceSurface,
		const propagator_t &	propagator,
		propagator_options_t	options,
		TrackExtrapolationStrategy	strategy,
		const Logger &	logger = *getDefaultLogger("TrackExtrapolation",                                             Logging::INFO) )

Extrapolate tracks to a reference surface.

Template Parameters

track_container_t	The track container type
propagator_t	The propagator type
propagator_options_t	The propagator options type

Parameters

trackContainer	The track container which is modified in-place
referenceSurface	The reference surface
propagator	The propagator
options	The propagator options
strategy	The extrapolation strategy
logger	The logger

Returns

The result of the extrapolation

extrapolateTrackToReferenceSurface()

template<TrackProxyConcept track_proxy_t, typename propagator_t, typename propagator_options_t>

Result< void > Acts::extrapolateTrackToReferenceSurface	(	track_proxy_t &	track,
		const Surface &	referenceSurface,
		const propagator_t &	propagator,
		propagator_options_t	options,
		TrackExtrapolationStrategy	strategy,
		const Logger &	logger = *getDefaultLogger("TrackExtrapolation",                                             Logging::INFO) )

Extrapolate a track to a reference surface.

Template Parameters

track_proxy_t	The track proxy type
propagator_t	The propagator type
propagator_options_t	The propagator options type

Parameters

track	The track which is modified in-place
referenceSurface	The reference surface
propagator	The propagator
options	The propagator options
strategy	The extrapolation strategy
logger	The logger

Returns

The result of the extrapolation

factorial()

template<std::unsigned_integral T>

T Acts::factorial ( const T N )

constexpr

Calculate the the factorial of an integer.

Parameters

N	Number of which the factorial is to be calculated

Returns

The factorial of N

fastCathetus()

template<typename T, typename... Args>

auto Acts::fastCathetus ( T hypotenuse, Args... args )

constexpr

Fast cathetus calculation for multiple arguments.

Parameters

hypotenuse	The hypotenuse value
args	Variable number of arguments to calculate the cathetus for

Returns

Square root of difference between the square of the hypotenuse and the square of the given arguments

fastHypot() [1/2]

template<typename T>

auto Acts::fastHypot ( T arg )

constexpr

Overload for single argument.

Parameters

arg	Single argument for which the hypotenuse is calculated

Returns

Absolute value of the argument

fastHypot() [2/2]

template<typename... T>

auto Acts::fastHypot ( T... args )

constexpr

Fast hypotenuse calculation for multiple arguments.

Parameters

args	Variable number of arguments

Returns

Square root of sum of squares of arguments

filledArray()

template<typename T, std::size_t N>

std::array< T, N > Acts::filledArray ( const T & defVal )

constexpr

creates an array of type T and size N and assigns all elements to the parsed default value def_val.

This basically allows for inline construction and initialization of class-member arrays

Parameters

defVal

Default value to assign

Returns

Array filled with the default value

findCharge()

std::optional< float > Acts::findCharge

(

PdgParticle

pdg

)

Find the charge for a given PDG particle number.

Parameters

pdg	PDG particle number

Returns

Charge in native units.

findChargeOfNucleus()

float Acts::findChargeOfNucleus

(

PdgParticle

pdg

)

Find the charge for a given PDG particle number of a nucleus.

Try its ground state first, and ultimately get the proton number from PDG

Parameters

pdg	PDG particle number for the nucleus

Returns

Charge in native units.

findFirstMeasurementState()

template<TrackProxyConcept track_proxy_t>

Result< typename track_proxy_t::ConstTrackStateProxy > Acts::findFirstMeasurementState

(

const track_proxy_t &

track

)

Find the first measurement state in a track.

Parameters

track

The track to search

Returns

Result containing the first measurement state proxy or error

findLastMeasurementState()

template<TrackProxyConcept track_proxy_t>

Result< typename track_proxy_t::ConstTrackStateProxy > Acts::findLastMeasurementState

(

const track_proxy_t &

track

)

Find the last measurement state in a track.

Parameters

track

The track to search

Returns

Result containing the last measurement state proxy or error

findMass()

std::optional< float > Acts::findMass

(

PdgParticle

pdg

)

Find the mass for a given PDG particle number.

Parameters

pdg	PDG particle number

Returns

Mass in native units.

findMassOfNucleus()

float Acts::findMassOfNucleus

(

PdgParticle

pdg

)

Find the mass for a given PDG particle number of a nucleus.

Try its ground state first, and ultimately get the mass from Bethe-Weizsacker formula

Parameters

pdg	PDG particle number for the nucleus

Returns

Mass in native units

findName()

std::optional< std::string_view > Acts::findName

(

PdgParticle

pdg

)

Find a descriptive particle name for a given PDG particle number.

Parameters

pdg	PDG particle number

Returns

Particle name.

findNameOfNucleus()

std::optional< std::string_view > Acts::findNameOfNucleus

(

PdgParticle

pdg

)

Find a descriptive particle name for a given PDG particle number of a nucleus.

Try to get the name from its ground state.

Parameters

pdg	PDG particle number for the nucleus

Returns

Particle name.

findParticleData()

std::optional< ParticleData > Acts::findParticleData

(

PdgParticle

pdg

)

Find all known particle data for a given PDG particle number.

Parameters

pdg	PDG particle number

Returns

Particle data if found

findTrackStateForExtrapolation()

template<TrackProxyConcept track_proxy_t>

Result< std::pair< typename track_proxy_t::ConstTrackStateProxy, double > > Acts::findTrackStateForExtrapolation	(	const GeometryContext &	geoContext,
		const track_proxy_t &	track,
		const Surface &	referenceSurface,
		TrackExtrapolationStrategy	strategy,
		const Logger &	logger = *getDefaultLogger("TrackExtrapolation",                                             Logging::INFO) )

Find a track state for extrapolation.

Template Parameters

track_proxy_t

The track proxy type

Parameters

geoContext	The geometry context
track	The track
referenceSurface	The reference surface
strategy	The extrapolation strategy
logger	The logger

Returns

The result of the search containing the track state and the distance to the reference surface

freeToSphericalDirectionJacobian()

Matrix< 2, 3 > Acts::freeToSphericalDirectionJacobian

(

const Vector3 &

direction

)

Calculates the Jacobian for free to spherical direction vector transformation.

Note

We use the direction vector as an input because the trigonometric simplify that way

Parameters

direction

The normalised direction vector

Returns

The Jacobian d(phi, theta) / d(dir_x, dir_y, dir_z)

getDefaultLogger()

std::unique_ptr< const Logger > Acts::getDefaultLogger	(	const std::string &	name,
		const Logging::Level &	lvl,
		std::ostream *	log_stream = &std::cout )

get default debug output logger

Parameters

[in]	name	name of the logger instance
[in]	lvl	debug threshold level
[in]	log_stream	output stream used for printing debug messages

This function returns a pointer to a Logger instance with the following decorations enabled:

• time stamps
• name of logging instance
• debug level

Returns

pointer to logging instance

getDummyLogger()

const Logger & Acts::getDummyLogger

(

)

Get a dummy logger that discards all output.

Returns

Reference to dummy logger instance

globalToLocalFromBin()

std::function< double(Acts::Vector3)> Acts::globalToLocalFromBin

(

Acts::AxisDirection &

type

)

return a function that return the coordinate corresponding to type of bin

Parameters

[in]

type

Type of bin

Returns

a coordinate transform function

Grid() [1/2]

template<typename T, class... Axes>

Acts::Grid	(	TypeTag< T >	,
		Axes &&...	axes )->Grid< T, Axes... >

Deduction guide for Grid with rvalue reference axes.

Parameters

axes	Variable number of axes (rvalue references)

Grid() [2/2]

template<typename T, class... Axes>

Acts::Grid	(	TypeTag< T >	,
		Axes &...	axes )->Grid< T, Axes... >

Deduction guide for Grid with lvalue reference axes.

Parameters

axes	Variable number of axes (lvalue references)

GridGlobalIterator()

template<typename T, class... Axes>

Acts::GridGlobalIterator	(	const Grid< T, Axes... > &	grid,
		std::size_t	idx )->GridGlobalIterator< T, Axes... >

Deduction guide for GridGlobalIterator.

Parameters

grid	Grid to iterate over
idx	Starting index

hashMix()

std::uint64_t Acts::hashMix ( std::uint64_t x )

constexpr

Apply a bit-mixing function to break up patterns in integer hash values.

Many standard hash functions (including std::hash for integers) are the identity, which leads to poor distribution when values are small or sequential. This function applies avalanche mixing so that small changes in the input produce large, uniformly-distributed changes in the output.

Uses the fmix64 finalizer from Austin Appleby's MurmurHash3.

See also

https://github.com/aappleby/smhasher/blob/master/src/MurmurHash3.cpp

Parameters

x	the value to mix

Returns

the mixed value

hashMixAndCombine()

template<typename T, typename... Rest>

std::uint64_t Acts::hashMixAndCombine ( const T & value, const Rest &... rest )

nodiscardconstexpr

Combine one or more values into a single hash.

Each value is passed through std::hash and hashMix, then folded together using an asymmetric combine step (fold-left). This produces well-distributed, order-dependent hashes even for small or sequential integer inputs where std::hash is typically the identity.

std::uint64_t h = Acts::hashMixAndCombine(a, b, c);

Template Parameters

T	the type of the first value
Rest	the types of any additional values

Parameters

value	the first value to hash
rest	additional values to fold in

Returns

the combined hash

hashString()

HashedString Acts::hashString ( std::string_view s )

consteval

Compile-time hash of string literal.

Parameters

s	String view to hash

Returns

Hashed string representation

hashStringDynamic()

HashedString Acts::hashStringDynamic ( std::string_view s )

constexpr

Runtime hash of string.

Parameters

s	String view to hash

Returns

Hashed string representation

hypotSquare()

template<typename... T>

auto Acts::hypotSquare ( T... args )

constexpr

Calculates the sum of squares of arguments.

Parameters

args	Variable number of arguments to square and sum

Returns

Sum of squares of all arguments

interpolate()

template<typename T, std::size_t N, class Point1, class Point2 = Point1, class Point3 = Point2>
requires Concepts::Interpolatable<T, N, Point1, Point2, Point3>

T Acts::interpolate	(	const Point1 &	point,
		const Point2 &	lowerCorner,
		const Point3 &	upperCorner,
		const std::array< T, N > &	values )

performs linear interpolation inside a hyper box

Template Parameters

T	type of values to be interpolated
N	number of hyper box corners
Point1	type specifying the input point
Point2	type specifying the lower corner of the hyper box
Point3	type specifying the upper corner of the hyper box

Parameters

point	point to which to interpolate
lowerCorner	generalized lower-left corner of hyper box (containing the minima of the hyper box along each dimension)
upperCorner	generalized upper-right corner of hyper box (containing the maxima of the hyper box along each dimension)
values	field values at the hyper box corners sorted in the canonical order defined below.

Returns

interpolated value at given point

Precondition

point must be inside the given hyper box, that is \(\text{lowerCorner}[i] \le \text{point}[i] \le \text{upperCorner}[i] \quad \forall i=0, \dots, d-1\).

Note

• Given U and V of value type T as well as two double a and b, then the following must be a valid expression a * U + b * V yielding an object which is (implicitly) convertible to T.
• All Point types must represent d-dimensional points and support coordinate access using operator[] which should return a double (or a value which is implicitly convertible). Coordinate indices must start at 0.
• N is the number of hyper box corners which is \(2^d\) where \(d\) is the dimensionality of the hyper box. The dimensionality must be consistent with the provided Point types.
• Definition of the canonical order for sorting the field values: The hyper box corners are numbered according to the following scheme. Each corner is defined by the set of lower/upper boundary limits in each dimension i. This can be represented by a binary code (from left to right) where a 0 stands for a lower bound along this axis and a 1 stand for the upper bound along this axis. The left most bit corresponds to the first dimension and the bits to the left correspond to the 2nd, 3rd... dimension. The binary code can be interpreted as integer which gives the number of the corresponding hyper box corner. The field values are ordered according to ascending hyper box corner numbers.
  As an example assume we have a 3D box with lowerCorner = (1,2,3) and upperCorner = (4,5,6). The eight corners with their bit patterns and corner numbers are:
  • (1,2,3): 000 = 0
  • (1,2,6): 001 = 1
  • (1,5,3): 010 = 2
  • (1,5,6): 011 = 3
  • (4,2,3): 100 = 4
  • (4,2,6): 101 = 5
  • (4,5,3): 110 = 6
  • (4,5,6): 111 = 7

ipow()

template<typename T>

T Acts::ipow ( T num, unsigned int pow )

consteval

Calculate the integer power of a number at compile time using recursion.

Todo

std::pow() will be constexpr in C++26 and this function can be removed

Template Parameters

T	The type of the base number, which should support multiplication by itself

Parameters

num	The base number to be raised to a power
pow	The exponent to which the base number is raised

Returns

The result of num raised to the power of pow

isBoundVectorValid()

bool Acts::isBoundVectorValid	(	const BoundVector &	v,
		bool	validateAngleRange,
		double	epsilon = 1e-6,
		double	maxAbsEta = std::numeric_limits< double >::infinity() )

Check if a bound vector is valid.

This checks the following:

• All values are finite
• (optionally) The phi value is in the range [-pi, pi)
• (optionally) The theta value is in the range [0, pi]

Parameters

v	The bound vector to check
validateAngleRange	If true, the phi and theta values are range checked
epsilon	The epsilon to use for the checks
maxAbsEta	The maximum allowed eta value

Returns

True if the bound vector is valid

isFreeVectorValid()

bool Acts::isFreeVectorValid	(	const FreeVector &	v,
		double	epsilon = 1e-6,
		double	maxAbsEta = std::numeric_limits< double >::infinity() )

Check if a free vector is valid.

This checks the following:

• All values are finite
• Direction is normalized

Parameters

v	The free vector to check
epsilon	The epsilon to use for the checks
maxAbsEta	The maximum allowed eta value

Returns

True if the free vector is valid

isNucleus()

constexpr bool Acts::isNucleus ( PdgParticle pdg )

staticconstexpr

Check if the PDG belongs to a nucleus, i.e.

if it has 10 digits. See PDG section "Monte Carlo Particle Numbering Scheme", point 16: https://pdg.lbl.gov/2025/reviews/rpp2024-rev-monte-carlo-numbering.pdf

Parameters

pdg	The PDG particle code

Returns

True if the PDG code represents a nucleus

joinStrings() [1/2]

template<std::ranges::range R>
requires std::convertible_to<std::ranges::range_value_t<R>, std::string_view>

std::string Acts::joinStrings	(	R &&	strings,
		std::string_view	delimiter )

Utuility to join a range of strings with a delimiter.

Accepts any range of elements convertible to std::string_view.

Parameters

strings	Range of strings to join
delimiter	Delimiter to insert between elements

Returns

Joined string

joinStrings() [2/2]

template<std::ranges::range R>
requires detail::formattable<std::ranges::range_value_t<R>, char>

std::string Acts::joinStrings	(	R &&	values,
		std::string_view	delimiter,
		std::format_string< const std::ranges::range_value_t< R > & >	format )

Utility to join a range of formattable elements with a delimiter and custom format string.

Parameters

values	Range of values to join
delimiter	Delimiter to insert between elements
format	Format string to apply to each element

Returns

Joined string

loadDD4hepGeometryModule()

std::shared_ptr< TrackingGeometry > Acts::loadDD4hepGeometryModule	(	const std::filesystem::path &	modulePath,
		const dd4hep::Detector &	detector,
		const Logger &	logger = getDummyLogger() )

Load a DD4hep geometry module shared library with the given detector, validate ABI compatibility, build and return the tracking geometry.

The returned deleter keeps the module loaded until the geometry is destroyed.

Parameters

modulePath	Path to the geometry module shared library.
detector	DD4hep detector instance passed to the module.
logger	Logger instance used by the module loader.

Returns

Shared pointer to the loaded tracking geometry.

loadGeometryModule()

std::shared_ptr< TrackingGeometry > Acts::loadGeometryModule	(	const std::filesystem::path &	modulePath,
		const Logger &	logger = getDummyLogger() )

Load a module shared library, validate ABI compatibility, build and return the tracking geometry.

The returned deleter keeps the module loaded until the geometry is destroyed. Throws if the module requires user data (e.g. a DD4hep module) — use the appropriate typed loader instead.

Parameters

modulePath	Path to the geometry module shared library.
logger	Logger instance used by the module loader.

Returns

Shared pointer to the loaded tracking geometry.

localIndices()

template<typename grid_type>

std::set< typename grid_type::index_t > Acts::localIndices	(	const grid_type &	grid,
		const std::vector< typename grid_type::point_t > &	queries,
		const std::vector< std::size_t > &	expansion = {} )

Helper method to fill local bins given a set of query points bin in between the extra points are filled, and a possible expansion of the bin window can be chosen.

Template Parameters

grid_type

the type of the grid that determines local binning

Parameters

grid	the grid used for this
queries	the grid positions for the bin queries
expansion	are the additional (configured) number of bins to expand the view

Returns

a set of unique indices

make_error_code() [1/12]

std::error_code Acts::make_error_code

(

Acts::CombinatorialKalmanFilterError

e

)

Create error code from CombinatorialKalmanFilterError.

Parameters

e	The error code enum value

Returns

Standard error code

make_error_code() [2/12]

std::error_code Acts::make_error_code

(

Acts::KalmanFitterError

e

)

Create error code from KalmanFitterError.

Parameters

e	The error code enum value

Returns

Standard error code

make_error_code() [3/12]

std::error_code Acts::make_error_code

(

Acts::MultiStepperError

e

)

Create error code from MultiStepperError.

Parameters

e	The error code enum value

Returns

Standard error code

make_error_code() [4/12]

std::error_code Acts::make_error_code

(

Acts::NavigatorError

e

)

Create error code from NavigatorError.

Parameters

e	The error code enum value

Returns

Standard error code

make_error_code() [5/12]

std::error_code Acts::make_error_code

(

Acts::PortalError

e

)

Create error code from PortalError.

Parameters

e	The error code enum value

Returns

Standard error code

make_error_code() [6/12]

std::error_code Acts::make_error_code

(

Acts::PropagatorError

e

)

Create error code from PropagatorError.

Parameters

e	The error code enum value

Returns

Standard error code

make_error_code() [7/12]

std::error_code Acts::make_error_code

(

Acts::SurfaceError

e

)

Create error code from SurfaceError.

Parameters

e	The error code enum value

Returns

Standard error code

make_error_code() [8/12]

std::error_code Acts::make_error_code

(

Acts::VertexingError

e

)

Create error code from VertexingError.

Parameters

e	The error code enum value

Returns

Standard error code

make_error_code() [9/12]

std::error_code Acts::make_error_code

(

EigenStepperError

e

)

Create error code from EigenStepperError.

Parameters

e	The error code enum value

Returns

Standard error code

make_error_code() [10/12]

std::error_code Acts::make_error_code

(

GsfError

e

)

Create error code from GsfError.

Parameters

e	The error code enum value

Returns

Standard error code

make_error_code() [11/12]

std::error_code Acts::make_error_code

(

SpacePointFormationError

e

)

Create error code from SpacePointFormationError.

Parameters

e	The error code enum value

Returns

Standard error code

make_error_code() [12/12]

std::error_code Acts::make_error_code

(

TrackExtrapolationError

e

)

Create error code from TrackExtrapolationError.

Parameters

e	The error code enum value

Returns

Standard error code

make_octree()

template<typename box_t>

box_t * Acts::make_octree	(	std::vector< std::unique_ptr< box_t > > &	store,
		const std::vector< box_t * > &	prims,
		std::size_t	max_depth = 1,
		typename box_t::value_type	envelope1 = 0 )

Build an octree from a list of bounding boxes.

Note

store and prims do not need to contain the same objects. store is only used to pass ownership back to the caller while preserving memory location.

Template Parameters

box_t

Works will all box types.

Parameters

store	Owns the created boxes by means of std::unique_ptr.
prims	Boxes to store. This is a read only vector.
max_depth	No subdivisions beyond this level.
envelope1	Envelope to add/subtract to dimensions in all directions.

Returns

Pointer to the top most bounding box, containing the entire octree

makeAbsolutePdgParticle()

constexpr PdgParticle Acts::makeAbsolutePdgParticle ( PdgParticle pdg )

staticconstexpr

Convert an anti-particle to its particle and leave particles as-is.

Parameters

pdg	The PDG particle code

Returns

The absolute PDG particle code

makeDirectionFromAxisTangents()

template<typename T>

Eigen::Matrix< T, 3, 1 > Acts::makeDirectionFromAxisTangents	(	T	tanAlpha,
		T	tanBeta )

Construct a normalized direction vector from the tangents of the x-axis to the z-axis and of the y-axis to the z-axis.

Parameters

tanAlpha	Tangent of the x-axis to the z-axis
tanBeta	Tangent of the y-axis to the z-axis

Returns

A normalized 3D direction vector constructed from the axis tangents

makeDirectionFromPhiEta()

template<typename T>

Eigen::Matrix< T, 3, 1 > Acts::makeDirectionFromPhiEta	(	T	phi,
		T	eta )

Construct a normalized direction vector from phi angle and pseudorapidity.

Parameters

phi	is the direction angle in the x-y plane.
eta	is the pseudorapidity towards the z-axis.

Returns

A normalized 3D direction vector constructed from phi and eta

Note

The input arguments intentionally use the same template type so that a compile error occurs if inconsistent input types are used. Avoids unexpected implicit type conversions and forces the user to explicitly cast mismatched input types.

makeDirectionFromPhiTheta()

template<typename T>

Eigen::Matrix< T, 3, 1 > Acts::makeDirectionFromPhiTheta	(	T	phi,
		T	theta )

Construct a normalized direction vector from phi and theta angle.

Parameters

phi	is the direction angle in radian in the x-y plane.
theta	is the polar angle in radian towards the z-axis.

Returns

A normalized 3D direction vector constructed from phi and theta

Note

The input arguments intentionally use the same template type so that a compile error occurs if inconsistent input types are used. Avoids unexpected implicit type conversions and forces the user to explicitly cast mismatched input types.

makeGrid() [1/4]

template<typename payload_t>

std::unique_ptr< IGrid > Acts::makeGrid

(

const IAxis &

a

)

Helper method to create a 1D grid from a single type-erased axis.

Template Parameters

payload_t

the grid payload type

Parameters

a

the axis

Returns

an IGrid unique ptr and hence transfers ownership

makeGrid() [2/4]

template<typename payload_t>

std::unique_ptr< IGrid > Acts::makeGrid	(	const IAxis &	a,
		const IAxis &	b )

Helper method to create a 2D grid from two type-erased axes.

Template Parameters

payload_t

the grid payload type

Parameters

a	the first axis
b	the second axis

Returns

an IGrid unique ptr and hence transfers ownership

makeGrid() [3/4]

template<typename payload_t>

std::unique_ptr< IGrid > Acts::makeGrid

(

const ProtoAxis &

a

)

Helper method to create a 1D grid from a single proto axis.

Template Parameters

payload_t

the grid payloat type

Parameters

a	the proto axis

Returns

an IGrid unique ptr and hence transfers ownership

Deprecated

Use makeGrid(const IAxis&) instead

makeGrid() [4/4]

template<typename payload_t>

std::unique_ptr< IGrid > Acts::makeGrid	(	const ProtoAxis &	a,
		const ProtoAxis &	b )

Helper method to create a 2D grid from a two proto axes.

Template Parameters

payload_t

the grid payloat type

Parameters

a	the first proto axis
b	the second proto axis

Returns

an IGrid unique ptr and hence transfers ownership

Deprecated

Use makeGrid(const IAxis&, const IAxis&) instead

makeNucleusGroundState()

constexpr PdgParticle Acts::makeNucleusGroundState ( PdgParticle pdg )

staticconstexpr

Convert an excited nucleus to its ground state.

PDG number of a nucleus has a form 10LZZZAAAI, where I is isomer level; I=0 is the ground state. See PDG section "Monte Carlo Particle Numbering Scheme", point 16: https://pdg.lbl.gov/2025/reviews/rpp2024-rev-monte-carlo-numbering.pdf

Parameters

pdg	The PDG particle code of the nucleus

Returns

The PDG particle code of the nucleus in its ground state

makePhiThetaFromDirection()

template<typename T>

Eigen::Matrix< T, 2, 1 > Acts::makePhiThetaFromDirection

(

const Eigen::Matrix< T, 3, 1 > &

unitDir

)

Construct a phi and theta angle from a direction vector.

Parameters

unitDir

3D vector indicating a direction

Returns

A 2D vector containing phi and theta angles [phi, theta]

mapMaterialPoints() [1/2]

MaterialGrid2D Acts::mapMaterialPoints

(

Grid2D &

grid

)

Average the material collected in a 2D grid and use it to create a 2D material grid.

Parameters

[in]

grid

The material collecting grid coordinate

Returns

The average material grid decomposed into classification numbers

mapMaterialPoints() [2/2]

MaterialGrid3D Acts::mapMaterialPoints

(

Grid3D &

grid

)

Average the material collected in a 3D grid and use it to create a 3D material grid.

Parameters

[in]

grid

The material collecting grid coordinate

Returns

The average material grid decomposed into classification numbers

matrixToBitset()

template<typename Derived>

auto Acts::matrixToBitset

(

const Eigen::PlainObjectBase< Derived > &

m

)

Convert an integer matrix to a bitset.

Note

How the bits are ordered depends on the storage type of the matrix being converted (row-major or col-major)

Template Parameters

Derived

Eigen base concrete type

Parameters

m	Matrix that is converted

Returns

The converted bitset.

normalizeBoundParameters()

BoundVector Acts::normalizeBoundParameters

(

const BoundVector &

boundParams

)

Normalize the bound parameter angles.

Parameters

boundParams

The bound parameters to normalize

Returns

The normalized bound parameters

numAxisDirections()

std::size_t Acts::numAxisDirections ( )

constexpr

Returns the total number of axis directions.

Returns

the number of axis directions

operator<<() [1/32]

std::ostream & Acts::operator<<	(	std::ostream &	os,
		AxisBoundaryType	bdt )

Stream operator for AxisBoundaryType.

Parameters

os	Output stream
bdt	AxisBoundaryType to output

Returns

Reference to output stream

operator<<() [2/32]

std::ostream & Acts::operator<<	(	std::ostream &	os,
		AxisDirection	aDir )

Output stream operator for AxisDirection.

Parameters

os	is the output stream
aDir	is the axis direction

Returns

the output stream

operator<<() [3/32]

std::ostream & Acts::operator<<	(	std::ostream &	os,
		AxisType	type )

Stream operator for AxisType.

Parameters

os	Output stream
type	AxisType to output

Returns

Reference to output stream

operator<<() [4/32]

std::ostream & Acts::operator<<	(	std::ostream &	os,
		BoundarySurfaceFace &	face )

Stream operator for BoundarySurfaceFace.

Parameters

os	Output stream
face	BoundarySurfaceFace to output

Returns

Reference to output stream

operator<<() [5/32]

template<typename T, typename U, std::size_t V>

std::ostream & Acts::operator<<	(	std::ostream &	os,
		const AxisAlignedBoundingBox< T, U, V > &	box )

Overload of the << operator for bounding boxes.

Template Parameters

T	entity type
U	value type
V	dimension

Parameters

os	The output stream
box	The bounding box

Returns

The given output stream.

operator<<() [6/32]

std::ostream & Acts::operator<<	(	std::ostream &	os,
		const ConstrainedStep &	step )

Stream operator for ConstrainedStep.

Parameters

os	Output stream
step	ConstrainedStep to output

Returns

Reference to output stream

operator<<() [7/32]

std::ostream & Acts::operator<<	(	std::ostream &	os,
		const IVisualization3D &	hlp )

Stream operator for IVisualization3D.

Parameters

os	The output stream
hlp	The helper instance

Returns

Reference to output stream

operator<<() [8/32]

std::ostream & Acts::operator<<	(	std::ostream &	os,
		const Material &	material )

Stream operator for Material.

Parameters

os	Output stream
material	Material to output

Returns

Reference to output stream

operator<<() [9/32]

std::ostream & Acts::operator<<	(	std::ostream &	os,
		const MaterialSlab &	materialSlab )

Stream operator for MaterialSlab.

Parameters

os	Output stream
materialSlab	MaterialSlab to output

Returns

Reference to output stream

operator<<() [10/32]

template<typename T, std::size_t D>

std::ostream & Acts::operator<<	(	std::ostream &	os,
		const Ray< T, D > &	ray )

Overload of the outstream operator.

Parameters

os	The out stream
ray	The ray to write to os

Returns

The outstream given in os

operator<<() [11/32]

std::ostream & Acts::operator<<	(	std::ostream &	os,
		const std::vector< AxisDirection > &	manyDir )

Output stream operator for a vector of AxisDirection.

Parameters

os	is the output stream
manyDir	is the vector of axis directions

Returns

the output stream

operator<<() [12/32]

std::ostream & Acts::operator<<	(	std::ostream &	os,
		const std::vector< DirectedProtoAxis > &	a )

Stream operator for vector of DirectedProtoAxis.

Parameters

os	Output stream
a	Vector of DirectedProtoAxis to output

Returns

Reference to output stream

operator<<() [13/32]

std::ostream & Acts::operator<<	(	std::ostream &	os,
		const std::vector< ProtoAxis > &	a )

Stream operator for vector of ProtoAxis.

Parameters

os	Output stream
a	Vector of ProtoAxis to output

Returns

Reference to output stream

operator<<() [14/32]

std::ostream & Acts::operator<<	(	std::ostream &	os,
		const TrackSelector::Config &	cuts )

Parameters

os	Output stream
cuts	Cuts to print

Returns

Reference to the output stream

operator<<() [15/32]

std::ostream & Acts::operator<<	(	std::ostream &	os,
		const TrackSelector::EtaBinnedConfig &	cfg )

Parameters

os	Output stream
cfg	Configuration to print

Returns

Reference to the output stream

operator<<() [16/32]

std::ostream & Acts::operator<<	(	std::ostream &	os,
		CuboidPortalShell::Face	face )

Output stream operator for the CuboidPortalShell::Face enum.

Parameters

os	The output stream
face	The face to output

Returns

The output stream

operator<<() [17/32]

std::ostream & Acts::operator<<	(	std::ostream &	os,
		CylinderPortalShell::Face	face )

Output stream operator for the CylinderPortalShell::Face enum.

Parameters

os	The output stream
face	The face to output

Returns

The output stream

operator<<() [18/32]

std::ostream & Acts::operator<<	(	std::ostream &	os,
		DiamondPortalShell::Face	face )

Parameters

os	The output stream
face	The face to output

Returns

The output stream

operator<<() [19/32]

std::ostream & Acts::operator<<	(	std::ostream &	os,
		GeometryIdentifier	id )

Stream operator for GeometryIdentifier.

Parameters

os	Output stream
id	GeometryIdentifier to output

Returns

Reference to output stream

operator<<() [20/32]

std::ostream & Acts::operator<<	(	std::ostream &	os,
		HadronType	hadron )

Stream operator for HadronType.

Parameters

os	Output stream
hadron	The hadron type to output

Returns

Reference to output stream

operator<<() [21/32]

std::ostream & Acts::operator<<	(	std::ostream &	os,
		IntersectionStatus	status )

Ostream-operator for the IntersectionStatus enum.

Parameters

os	Output stream
status	IntersectionStatus to output

Returns

Reference to output stream

operator<<() [22/32]

std::ostream & Acts::operator<<	(	std::ostream &	os,
		MaterialUpdateMode	mode )

Stream operator for MaterialUpdateMode.

Parameters

os	Output stream
mode	MaterialUpdateMode to output

Returns

Reference to output stream

operator<<() [23/32]

std::ostream & Acts::operator<<	(	std::ostream &	os,
		PdgParticle	pdg )

Print PDG particle numbers with a descriptive name.

Parameters

os	Output stream
pdg	PDG particle to output

Returns

Reference to output stream

operator<<() [24/32]

std::ostream & Acts::operator<<	(	std::ostream &	os,
		TrackStatePropMask	mask )

Stream operator for TrackStatePropMask.

Parameters

os	Output stream
mask	TrackStatePropMask to output

Returns

Reference to output stream

operator<<() [25/32]

std::ostream & Acts::operator<<	(	std::ostream &	os,
		TrapezoidPortalShell::Face	face )

Output stream operator for the TrapezoidPortalShell::Face enum.

Parameters

os	The output stream
face	The face to output

Returns

The output stream

operator<<() [26/32]

std::ostream & Acts::operator<<	(	std::ostream &	os,
		VolumeAttachmentStrategy	strategy )

Stream operator for VolumeAttachmentStrategy.

Parameters

os	Output stream
strategy	VolumeAttachmentStrategy to output

Returns

Reference to output stream

operator<<() [27/32]

std::ostream & Acts::operator<<	(	std::ostream &	os,
		VolumeResizeStrategy	strategy )

Stream operator for VolumeResizeStrategy.

Parameters

os	Output stream
strategy	VolumeResizeStrategy to output

Returns

Reference to output stream

operator<<() [28/32]

std::ostream & Acts::operator<<	(	std::ostream &	sl,
		const Extent &	rhs )

Overload of << operator for std::ostream for debug output.

Parameters

sl	Output stream
rhs	Extent to output

Returns

Reference to output stream

operator<<() [29/32]

std::ostream & Acts::operator<<	(	std::ostream &	sl,
		const GlueVolumesDescriptor &	gvd )

Stream operator for GlueVolumesDescriptor.

Parameters

sl	Output stream
gvd	GlueVolumesDescriptor to output

Returns

Reference to output stream

operator<<() [30/32]

std::ostream & Acts::operator<<	(	std::ostream &	sl,
		const Volume &	vol )

Overload of << operator for std::ostream for debug output.

Parameters

sl	Output stream
vol	Volume to output

Returns

Reference to output stream

operator<<() [31/32]

std::ostream & Acts::operator<<	(	std::ostream &	sl,
		const VolumeBounds &	vb )

Overload of << operator for std::ostream for debug output.

Parameters

sl	Output stream
vb	VolumeBounds to output

Returns

Reference to output stream

operator<<() [32/32]

std::ostream & Acts::operator<<	(	std::ostream &	sl,
		const VolumeBounds::BoundsType &	bt )

Stream operator for VolumeBounds::BoundsType.

Parameters

sl	Output stream
bt	BoundsType to output

Returns

Reference to output stream

operator==()

bool Acts::operator==	(	const VolumeBounds &	lhs,
		const VolumeBounds &	rhs )

Equality comparison for VolumeBounds.

Parameters

lhs	Left-hand side VolumeBounds
rhs	Right-hand side VolumeBounds

Returns

True if bounds are equal

outputIndices()

template<typename local_bin>

std::string Acts::outputIndices

(

const std::set< local_bin > &

lbins

)

Helper method to screen output the local bins.

Template Parameters

local_bin

the type of the local bins

Parameters

lbins

the local bins

Returns

a string containing the local bins ordered in a set

parsePdgParticle()

PdgParticle Acts::parsePdgParticle

(

const std::string &

name

)

Parse a PdgParticle from a particle name string.

Supports common particle names like "e-", "e+", "mu-", "mu+", "tau-", "tau+", "gamma", "pi0", "pi+", "pi-", "K+", "K-", "n", "n~", "p", "p~", "Pb".

Parameters

name	The particle name string

Returns

The corresponding PdgParticle enum value

Exceptions

std::invalid_argument

if the name is not recognized

pdgToShortAbsString()

std::optional< std::string_view > Acts::pdgToShortAbsString

(

PdgParticle

pdg

)

Get short absolute string representation of PDG particle.

Parameters

pdg	PDG particle number

Returns

Optional string view of particle name

pow()

template<typename T, std::integral P>

T Acts::pow ( T x, P p )

constexpr

Calculates the ordinary power of the number x.

Parameters

x	Number to take the power from
p	Power to take

Returns

x raised to the power p

printEigenDecomposition()

std::string Acts::printEigenDecomposition

(

const Eigen::Ref< const Eigen::MatrixXd > &

mat

)

Print the eigen decomposition of a symmetric matrix in terms of eigen values and eigen vectors.

Parameters

mat	Symmetric matrix which is to be decomposed. Accepts any fixed- or dynamic-size matrix expression via Eigen::Ref.

Returns

: The string containing the eigen decomposition

Note

Defined out-of-line in StringHelpers.cpp so that the heavy eigen-solver is instantiated only once instead of in every translation unit and for every matrix size.

product()

template<std::unsigned_integral T>

T Acts::product ( const T lowerN, const T upperN )

constexpr

Calculates the product of all integers within the given integer range (nLower)(nLower+1)(...)(upper-1)(upper).

If lowerN is bigger than upperN, the function returns one.

Parameters

lowerN	Lower range of the product calculation
upperN	Upper range of the product calculation

Returns

Product result

projectorToSubspaceIndices()

template<std::size_t kFullSize, typename Derived>

SubspaceIndices< kFullSize > Acts::projectorToSubspaceIndices

(

const Eigen::DenseBase< Derived > &

projector

)

Convert a projector to subspace indices.

Template Parameters

kFullSize	the full size of the subspace
Derived	the derived type

Parameters

projector

the projector

Returns

the subspace indices

range_medium()

template<typename T>

std::tuple< typename T::value_type, double > Acts::range_medium

(

const T &

tseries

)

Return range and medium of an unsorted numeric series.

Template Parameters

T	a numeric series

Parameters

tseries

is the number series

Returns

[ range, medium ] in an tuple

rangeContainsSubstring()

template<typename R>

bool Acts::rangeContainsSubstring	(	const R &	range,
		std::string_view	value )

This function checks if at least one string from a given range is contained within a specified string (value).

Template Parameters

R	The type of the range (e.g., vector<string>, list<string>, array<string>).

Parameters

range	The range to search within.
value	The string in which we search for substrings from the range

Returns

true if a such a string in range is found, false otherwise.

rangeContainsValue()

template<typename R, typename T>

bool Acts::rangeContainsValue	(	const R &	range,
		const T &	value )

This can be replaced with C++23 to use the std::ranges::contains method.

This function searches through the given range for a specified value and returns true if the value is found, or false otherwise.

Template Parameters

R	The type of the range (e.g., vector, list, array).
T	The type of the value to search for within the range.

Parameters

range	The range to search within. This can be any range-compatible container.
value	The value to search for in the range.

Returns

true if the value is found within the range, false otherwise.

reduceMixtureWithKLDistanceNaive()

void Acts::reduceMixtureWithKLDistanceNaive	(	std::vector< GsfComponent > &	cmpCache,
		std::size_t	maxCmpsAfterMerge,
		const Surface &	surface )

Naive implementation of component reduction with KL-distance.

Recomputes all distances in every iteration without any caching or optimization. This serves as a baseline for testing and benchmarking the optimized version.

Parameters

cmpCache	the component collection
maxCmpsAfterMerge	the number of components we want to reach
surface	the surface type on which the components are

reflectBoundParameters()

BoundVector Acts::reflectBoundParameters

(

const BoundVector &

boundParams

)

Reflect bound track parameters.

Parameters

boundParams

Bound track parameters vector

Returns

Reflected bound track parameters vector

reflectFreeParameters()

FreeVector Acts::reflectFreeParameters

(

const FreeVector &

freeParams

)

Reflect free track parameters.

Parameters

freeParams

Free track parameters vector

Returns

Reflected free track parameters vector

safeExp()

template<typename T>

T Acts::safeExp ( T val )

constexprnoexcept

Calculate the exponential function while avoiding FPEs.

Parameters

val	argument for which the exponential function should be evaluated.

Returns

0 in the case of underflow, std::numeric_limits<T>::infinity in the case of overflow, std::exp(val) else

safeInverse()

template<typename MatrixType, typename ResultType = MatrixType>

std::optional< ResultType > Acts::safeInverse ( const MatrixType & m )

noexcept

FPE "safe" functions.

Our main motivation for this is that users might have a strict FPE policy which would flag every single occurrence as a failure and then somebody has to investigate. Since we are processing a high number of events and floating point numbers sometimes work in mysterious ways the caller of this function might want to hide FPEs and handle them in a more controlled way. Calculate the inverse of an Eigen matrix after checking if it can be numerically inverted. This allows to catch potential FPEs before they occur. For matrices up to 4x4, the inverse is computed directly. For larger matrices, and dynamic matrices the FullPivLU is used.

Template Parameters

Derived	Eigen derived concrete type
Result	Eigen result type defaulted to input type

Parameters

m	Eigen matrix to invert

Returns

The theta value

serializeSubspaceIndices()

template<std::size_t FullSize>
requires (FullSize <= 8)

SerializedSubspaceIndices Acts::serializeSubspaceIndices ( const SubspaceIndices< FullSize > & indices )

static

Serialize subspace indices to a single 64 bit integer.

Template Parameters

FullSize

the full size of the subspace

Parameters

indices

the subspace indices

Returns

the serialized subspace indices

sinc()

double Acts::sinc

(

double

x

)

Calculate the sinc function, defined as sin(x)/x, with a special handling for x=0 to avoid numerical instability.

Parameters

x	The input value for which to calculate the sinc function

Returns

The value of sinc(x)

slowCathetus()

template<typename T, typename... Args>

auto Acts::slowCathetus ( T hypotenuse, Args... args )

constexpr

Slow but more accurate cathetus calculation for multiple arguments.

Note

For 2 arguments, the fast and slow cathetus are identical as they both use the same formula.

Parameters

hypotenuse	The hypotenuse value
args	Variable number of arguments to calculate the cathetus for

Returns

Square root of difference between the square of the hypotenuse and the square of the given arguments

slowHypot() [1/4]

template<typename T>

auto Acts::slowHypot ( T arg )

constexpr

Overload for single argument.

Parameters

arg	Single argument for which the hypotenuse is calculated

Returns

Absolute value of the argument

slowHypot() [2/4]

template<typename T>

auto Acts::slowHypot ( T x, T y )

constexpr

Overload for two arguments.

Parameters

x	First argument
y	Second argument

Returns

Square root of sum of squares of x and y

slowHypot() [3/4]

template<typename T>

auto Acts::slowHypot ( T x, T y, T z )

constexpr

Overload for three arguments.

Parameters

x	First argument
y	Second argument
z	Third argument

Returns

Square root of sum of squares of x, y and z

slowHypot() [4/4]

template<typename... T>

auto Acts::slowHypot ( T... args )

constexpr

Slow but more accurate hypotenuse calculation for multiple arguments.

Parameters

args	Variable number of arguments

Returns

Square root of sum of squares of arguments

smoothTrack()

template<TrackProxyConcept track_proxy_t, typename smoother_t = GainMatrixSmoother>

Result< void > Acts::smoothTrack	(	const GeometryContext &	geoContext,
		track_proxy_t &	track,
		const Logger &	logger = *getDefaultLogger("TrackSmoother", Logging::INFO),
		smoother_t	smoother = GainMatrixSmoother() )

Smooth a track using the gain matrix smoother.

Template Parameters

track_proxy_t	The track proxy type
smoother_t	The smoother type

Parameters

geoContext	The geometry context
track	The track to smooth
logger	The logger
smoother	The smoother

Returns

The result of the smoothing

smoothTracks()

template<TrackContainerFrontend track_container_t>

Result< void > Acts::smoothTracks	(	const GeometryContext &	geoContext,
		const track_container_t &	trackContainer,
		const Logger &	logger = *getDefaultLogger("TrackSmoother", Logging::INFO) )

Smooth tracks using the gain matrix smoother.

Template Parameters

track_container_t

The track container type

Parameters

geoContext	The geometry context
trackContainer	The track container
logger	The logger

Returns

The result of the smoothing

sphericalToFreeDirectionJacobian()

Matrix< 3, 2 > Acts::sphericalToFreeDirectionJacobian

(

const Vector3 &

direction

)

Calculates the Jacobian for spherical to free direction vector transformation.

Note

We use the direction vector as an input because the trigonometric simplify that way

Parameters

direction

The normalised direction vector

Returns

The Jacobian d(dir_x, dir_y, dir_z) / d(phi, theta)

square()

template<typename T>

auto Acts::square ( T x )

constexpr

Returns the square of the passed number.

Parameters

x	The number to square

Returns

The square of the input

subtractBoundParameters()

BoundVector Acts::subtractBoundParameters	(	const BoundVector &	lhs,
		const BoundVector &	rhs )

Subtract bound parameters and take care of angle periodicity for phi and theta.

This is intended for small differences only i.e. KF updates.

Parameters

lhs	The left hand side bound parameters
rhs	The right hand side bound parameters

Returns

The difference of the bound parameters

sumUpToN()

template<std::integral T>

T Acts::sumUpToN ( const T N )

constexpr

Calculates the sum of 1 + 2 + 3+ ... + N using the Gaussian sum formula.

Parameters

N	Number until which the sum runs

Returns

Sum of integers from 1 to N

symMatIndices()

template<std::size_t N>
requires (N > 1)

std::array< std::size_t, 2 > Acts::symMatIndices ( const std::size_t k )

constexpr

Map an unrolled vector index to the indices of the lower triangular part of a symmetric N x N matrix.

Inverse of vecIdxFromSymMat.

Parameters

k	The unrolled vector index

Returns

A pair of indices (i, j) such that the element at (i, j) in the symmetric matrix corresponds to the k-th element in the unrolled vector.

template_switch()

template<template< std::size_t > class Callable, std::size_t N, std::size_t NMAX, typename... Args>

decltype(auto) Acts::template_switch	(	std::size_t	v,
		Args &&...	args )

Dispatch a call based on a runtime value on a function taking the value at compile time.

This function allows to write a templated functor, which accepts a std::size_t like parameter at compile time. It is then possible to make a call to the corresponding instance of the functor based on a runtime value. To achieve this, the function essentially created a if cascade between N and NMAX, attempting to find the right instance. Because the cascade is visible to the compiler entirely, it should be able to optimize.

Template Parameters

Callable	Type which takes a std::size_t as a compile time param
N	Value from which to start the dispatch chain, i.e. 0 in most cases
NMAX	Maximum value up to which to attempt a dispatch

Parameters

v	The runtime value to dispatch on
args	Additional arguments passed to Callable::invoke().

Returns

The result of calling the dispatched template instance

Note

Callable is expected to have a static member function invoke that is callable with Args

template_switch_lambda()

template<std::size_t N, std::size_t NMAX, typename Lambda, typename... Args>

decltype(auto) Acts::template_switch_lambda	(	std::size_t	v,
		Lambda &&	func,
		Args &&...	args )

Alternative version of template_switch which accepts a generic lambda and communicates the dimension via an integral constant type.

Template Parameters

N	Value from which to start the dispatch chain, i.e. 0 in most cases
NMAX	Maximum value up to which to attempt a dispatch

Parameters

v	The runtime value to dispatch on
func	The lambda to invoke
args	Additional arguments passed to func

Returns

The result of calling the dispatched lambda function

toArray()

template<std::size_t kDIM, typename value_t>

std::array< value_t, kDIM > Acts::toArray

(

const std::vector< value_t > &

vecvals

)

Converts a vector to a fixed-size array with truncating or padding.

This function copies elements from the input vector into a fixed-size array. If the vector contains more than kDIM elements, the array is truncated to fit. If the vector contains fewer elements than kDIM, the remaining array elements are value-initialized (default-initialized, i.e., filled with zero or default values).

Template Parameters

kDIM	The size of the resulting array.
value_t	The type of elements in the vector and the array.

Parameters

vecvals

The input vector to be converted to an array.

Returns

An array containing the first kDIM elements of the vector.

toString() [1/4]

std::string Acts::toString	(	const Acts::Transform3 &	transform,
		int	precision = 4,
		const std::string &	offset = "" )

Print out a transform in a structured way.

Parameters

transform	The transform to print
precision	Numeric output precision
offset	Offset in front of matrix lines

Returns

The printed string

toString() [2/4]

std::string Acts::toString	(	const Acts::Translation3 &	translation,
		int	precision = 4 )

Print out a translation in a structured way.

Parameters

translation	The translation to print
precision	Numeric output precision

Returns

The printed string

toString() [3/4]

template<typename derived_t>

std::string Acts::toString	(	const Eigen::MatrixBase< derived_t > &	matrix,
		int	precision = 4,
		const std::string &	offset = "" )

Print out a matrix in a structured way.

Template Parameters

derived_t

Type of the matrix

Parameters

matrix	The matrix to print
precision	Numeric output precision
offset	Offset in front of matrix lines

Returns

The printed string

toString() [4/4]

std::string Acts::toString	(	const std::vector< double > &	pVector,
		int	precision = 4 )

Print out a vector of double.

Parameters

pVector	The vector to print
precision	Numeric output precision

Returns

A formatted string representation of the vector

toUnderlying()

template<typename enum_t>

std::underlying_type_t< enum_t > Acts::toUnderlying ( enum_t value )

constexpr

Convert enum to its underlying type value.

Parameters

value

Enum value to convert

Returns

Underlying type value

TrackContainer() [1/3]

template<TrackContainerBackend track_container_t, typename traj_t>

Acts::TrackContainer	(	const track_container_t &	container,
		const traj_t &	traj )->TrackContainer< track_container_t, traj_t, ConstRefHolder >

Deduction guide for TrackContainer with const references.

Parameters

container	Const track container reference
traj	Const trajectory reference

TrackContainer() [2/3]

template<TrackContainerBackend track_container_t, typename traj_t>

Acts::TrackContainer	(	track_container_t &&	container,
		traj_t &&	traj )->TrackContainer< track_container_t, traj_t, ValueHolder >

Deduction guide for TrackContainer with rvalue references.

Parameters

container	Track container rvalue reference
traj	Trajectory rvalue reference

TrackContainer() [3/3]

template<TrackContainerBackend track_container_t, typename traj_t>

Acts::TrackContainer	(	track_container_t &	container,
		traj_t &	traj )->TrackContainer< track_container_t, traj_t, RefHolder >

Deduction guide for TrackContainer with lvalue references.

Parameters

container	Track container reference
traj	Trajectory reference

transformBoundToFreeParameters()

FreeVector Acts::transformBoundToFreeParameters	(	const Surface &	surface,
		const GeometryContext &	geoCtx,
		const BoundVector &	boundParams )

Transform bound track parameters into equivalent free track parameters.

Parameters

surface	Surface onto which the input parameters are bound
geoCtx	Geometry context for the local-to-global transformation
boundParams	Bound track parameters vector

Returns

Equivalent free trackparameters vector

transformFreeToBoundParameters() [1/2]

Result< BoundVector > Acts::transformFreeToBoundParameters	(	const FreeVector &	freeParams,
		const Surface &	surface,
		const GeometryContext &	geoCtx,
		double	tolerance = s_onSurfaceTolerance )

Convert free track parameters to bound track parameters.

Parameters

freeParams	Free track parameters vector
surface	Surface onto which the parameters are bound
geoCtx	Geometry context for the global-to-local transformation
tolerance	Tolerance used for globalToLocal

Returns

Bound track parameters vector on the given surface

transformFreeToBoundParameters() [2/2]

Result< BoundVector > Acts::transformFreeToBoundParameters	(	const Vector3 &	position,
		double	time,
		const Vector3 &	direction,
		double	qOverP,
		const Surface &	surface,
		const GeometryContext &	geoCtx,
		double	tolerance = s_onSurfaceTolerance )

Convert position and direction to bound track parameters.

Parameters

position	Global track three-position
time	Global track time
direction	Global direction three-vector; normalization is ignored.
qOverP	Charge-over-momentum-like parameter
surface	Surface onto which the parameters are bound
geoCtx	Geometry context for the global-to-local transformation
tolerance	Tolerance used for globalToLocal

Returns

Equivalent bound parameters vector on the given surface

transformFreeToCurvilinearParameters() [1/2]

BoundVector Acts::transformFreeToCurvilinearParameters	(	double	time,
		const Vector3 &	direction,
		double	qOverP )

Convert direction to curvilinear track parameters.

Parameters

time	Global track time
direction	Global direction three-vector; normalization is ignored.
qOverP	Charge-over-momentum-like parameter

Returns

Equivalent bound parameters vector on the curvilinear surface

Note

The parameters are assumed to be defined at the origin of the curvilinear frame derived from the direction vector. The local coordinates are zero by construction.

transformFreeToCurvilinearParameters() [2/2]

BoundVector Acts::transformFreeToCurvilinearParameters	(	double	time,
		double	phi,
		double	theta,
		double	qOverP )

Convert direction angles to curvilinear track parameters.

Parameters

time	Global track time
phi	Global transverse direction angle
theta	Global longitudinal direction angle
qOverP	Charge-over-momentum-like parameter

Returns

Equivalent bound parameters vector on the curvilinear surface

Note

The parameters are assumed to be defined at the origin of the curvilinear frame derived from the direction angles. The local coordinates are zero by construction.

trimTrack()

template<TrackProxyConcept track_proxy_t>
requires (!track_proxy_t::ReadOnly)

void Acts::trimTrack	(	track_proxy_t	track,
		bool	trimHoles,
		bool	trimOutliers,
		bool	trimMaterial,
		bool	trimOtherNoneMeasurement )

Helper function to trim track states from the front and back of a track.

Template Parameters

track_proxy_t

the track proxy type

Parameters

track	the track to trim
trimHoles	whether to trim holes
trimOutliers	whether to trim outliers
trimMaterial	whether to trim pure material states
trimOtherNoneMeasurement	whether to trim other, non measurement, states

trimTrackBack()

template<TrackProxyConcept track_proxy_t>
requires (!track_proxy_t::ReadOnly)

void Acts::trimTrackBack	(	track_proxy_t	track,
		bool	trimHoles,
		bool	trimOutliers,
		bool	trimMaterial,
		bool	trimOtherNoneMeasurement )

Helper function to trim track states from the back of a track.

Template Parameters

track_proxy_t

the track proxy type

Parameters

track	the track to trim
trimHoles	whether to trim holes
trimOutliers	whether to trim outliers
trimMaterial	whether to trim pure material states
trimOtherNoneMeasurement	whether to trim other, non measurement, states

trimTrackFront()

template<TrackProxyConcept track_proxy_t>
requires (!track_proxy_t::ReadOnly)

void Acts::trimTrackFront	(	track_proxy_t	track,
		bool	trimHoles,
		bool	trimOutliers,
		bool	trimMaterial,
		bool	trimOtherNoneMeasurement )

Helper function to trim track states from the front of a track.

Template Parameters

track_proxy_t

the track proxy type

Parameters

track	the track to trim
trimHoles	whether to trim holes
trimOutliers	whether to trim outliers
trimMaterial	whether to trim pure material states
trimOtherNoneMeasurement	whether to trim other, non measurement, states

typeHash()

template<typename T>

std::uint64_t Acts::typeHash

(

)

Hash for a type.

Since it's not possible to hash a type at compile-time, this function returns a runtime hash but caches it in a static variable.

Template Parameters

T	Type to hash

Returns

Hashed string representation

unpackConstSmartPointers()

template<SmartPointerConcept T>

std::vector< std::add_pointer_t< std::add_const_t< typename T::element_type > > > Acts::unpackConstSmartPointers

(

const std::vector< T > &

items

)

Helper function to unpack a vector of smart pointers (e.g.

shared_ptr ) into a vector of raw const pointers

Template Parameters

T	the stored type

Parameters

items

The vector of smart pointers

Returns

The unpacked vector

unpackSmartPointers() [1/2]

template<typename T>

std::vector< const T * > Acts::unpackSmartPointers

(

const std::vector< std::shared_ptr< const T > > &

items

)

Helper function to unpack a vector of shared_ptr into a vector of raw pointers (const version).

Template Parameters

T	the stored type

Parameters

items

The vector of shared_ptr

Returns

The unpacked vector

unpackSmartPointers() [2/2]

template<SmartPointerConcept T>

std::vector< std::add_pointer_t< typename T::element_type > > Acts::unpackSmartPointers

(

const std::vector< T > &

items

)

Helper function to unpack a vector of shared_ptr into a vector of raw pointers.

Template Parameters

T	the stored type

Parameters

items

The vector of shared_ptr

Returns

The unpacked vector

vecIdxFromSymMat()

template<std::size_t N>
requires (N > 0)

std::size_t Acts::vecIdxFromSymMat ( const std::size_t i, const std::size_t k )

constexpr

Map the indices of the lower triangular part of a symmetric N x N matrix to an unrolled vector index.

Parameters

i	The row index of the symmetric matrix
k	The column index of the symmetric matrix

Returns

The corresponding vector index in the unrolled storage

visit_measurement() [1/2]

template<typename L, typename A, typename B>

auto Acts::visit_measurement	(	const A &	param,
		const B &	cov,
		std::size_t	dim,
		L &&	lambda )

Dispatch a lambda call on an overallocated parameter vector and covariance matrix, based on a runtime dimension value.

Inside the lambda call, the vector and matrix will have fixed dimensions, but will still point back to the originally given overallocated values.

Template Parameters

L	The lambda type
A	The parameter vector type
B	The covariance matrix type

Note

No requirements on A and B are made, to enable a single overload for both const and non-const matrices/vectors.

Parameters

param	The parameter vector
cov	The covariance matrix
dim	The actual dimension as a runtime value
lambda	The lambda to call with the statically sized subsets

Returns

The result of calling the lambda with the statically sized measurement components

visit_measurement() [2/2]

template<typename L, typename... Args>

auto Acts::visit_measurement	(	std::size_t	dim,
		L &&	lambda,
		Args &&...	args )

Dispatch a generic lambda on a measurement dimension.

This overload doesn't assume anything about what is needed inside the lambda, it communicates the dimension via an integral constant type

Template Parameters

L	The generic lambda type to call

Parameters

dim	The runtime dimension of the measurement
lambda	The generic lambda instance to call
args	Additional arguments passed to lambda

Returns

Returns the lambda return value

zip()

template<typename... R>

auto Acts::zip

(

R &&...

r

)

Function that allows to zip some ranges to be used in a range-based for loop.

When wanting to mutate the entries, the result must be captured by value:

for(auto [a, b, c] : zip(ra, rb, rc)) { a+=2; }

Template Parameters

R	The ranges type pack

Parameters

r	The ranges parameter pack

Note

the behaviour is undefined if the ranges do not have equal range

Returns

Zip object providing iteration over multiple ranges simultaneously

Variable Documentation

kBoundSubspaceIndicesInvalid

BoundSubspaceIndices Acts::kBoundSubspaceIndicesInvalid

staticconstexpr

Initial value:

= {
    eBoundSize, eBoundSize, eBoundSize, eBoundSize, eBoundSize, eBoundSize}

type alias for indices of bound track parameters subspace

used to specify which components of the bound track parameters are being referenced

kNavigationPolicyStateSbo

std::size_t Acts::kNavigationPolicyStateSbo = 128

staticconstexpr

Small-buffer size (in bytes) for a type-erased navigation policy state.

Sized so the largest policy state is stored inline, keeping the per-volume-entry pushState() on the navigation hot path free of heap allocations. A static_assert in pushState() guards against silent heap fallback: bump this value if a policy needs a larger state.

kSeedIndexInvalid

SeedIndex Acts::kSeedIndexInvalid

staticconstexpr

Initial value:

=
    std::numeric_limits<SeedIndex>::max()

Sentinel value for an invalid / unset seed EDM related index.

kSpacePointIndexInvalid

SpacePointIndex Acts::kSpacePointIndexInvalid

staticconstexpr

Initial value:

=
    std::numeric_limits<SpacePointIndex>::max()

Sentinel value for an invalid / unset space point EDM related index.

kTrackIndexInvalid

TrackIndexType Acts::kTrackIndexInvalid

staticconstexpr

Initial value:

=
    std::numeric_limits<TrackIndexType>::max()

Sentinel value for an invalid / unset track EDM related index.

s_onSurfaceTolerance

double Acts::s_onSurfaceTolerance = 1e-4

staticconstexpr

Tolerance for being on Surface.

Note

This is intentionally given w/o an explicit unit to avoid having to include the units header unnecessarily. With the native length unit of mm this corresponds to 0.1um.

s_planeYZ

const Transform3 Acts::s_planeYZ

static

Initial value:

=
    AngleAxis3(std::numbers::pi / 2., Vector3::UnitY()) *
    AngleAxis3(std::numbers::pi / 2., Vector3::UnitZ()) *
    Transform3::Identity()

YZ plane transformation.

s_planeZX

const Transform3 Acts::s_planeZX

static

Initial value:

=
    AngleAxis3(-std::numbers::pi / 2., Vector3::UnitX()) *
    AngleAxis3(-std::numbers::pi / 2., Vector3::UnitZ()) *
    Transform3::Identity()

ZX plane transformation.

SupportsBoundParameters_v

template<typename stepper_t>

bool Acts::SupportsBoundParameters_v

constexpr

Initial value:

=
    SupportsBoundParameters<stepper_t>::value

Variable template for checking bound parameters support.