Class CylinderSurface

Inheritance Relationships

Base Type

Derived Type

Class Documentation

class Acts::CylinderSurface : public Acts::Surface

Class for a CylinderSurface in the TrackingGeometry.

It inherits from Surface.

The cylinder surface has a special role in the TrackingGeometry, since it builds the surfaces of all TrackingVolumes at container level for a cylindrical tracking geometry.

_build/doxygen-xml/CylinderSurface.png

Subclassed by Acts::CylinderLayer

Public Functions

CylinderSurface() = delete
~CylinderSurface() override = default
AlignmentToPathMatrix alignmentToPathDerivative(const GeometryContext &gctx, const FreeVector &parameters) const final

Calculate the derivative of path length at the geometry constraint or point-of-closest-approach w.r.t.

alignment parameters of the surface (i.e. local frame origin in global 3D Cartesian coordinates and its rotation represented with extrinsic Euler angles)

Return

Derivative of path length w.r.t. the alignment parameters

Parameters

  • gctx: The current geometry context object, e.g. alignment

  • parameters: is the free parameters

Vector3 binningPosition(const GeometryContext &gctx, BinningValue bValue) const final

The binning position method - is overloaded for r-type binning.

Return

is the global position to be used for binning

Parameters

  • gctx: The current geometry context object, e.g. alignment

  • bValue: is the type of global binning to be done

const CylinderBounds &bounds() const final

This method returns the CylinderBounds by reference.

Result<Vector2> globalToLocal(const GeometryContext &gctx, const Vector3 &position, const Vector3 &momentum, double tolerance = s_onSurfaceTolerance) const final

Global to local transformation.

Return

a Result<Vector2> which can be !ok() if the operation fails

Parameters

  • gctx: The current geometry context object, e.g. alignment

  • position: is the global position to be transformed

  • momentum: is the global momentum (ignored in this operation)

  • tolerance: optional tolerance within which a point is considered valid on surface

SurfaceIntersection intersect(const GeometryContext &gctx, const Vector3 &position, const Vector3 &direction, const BoundaryCheck &bcheck) const final

Straight line intersection schema from position/direction.

If possible returns both solutions for the cylinder

Parameters

  • gctx: The current geometry context object, e.g. alignment

  • position: The position to start from

  • direction: The direction at start

  • bcheck: the Boundary Check

Return

SurfaceIntersection object (contains intersection & surface)

ActsMatrix<2, 3> localCartesianToBoundLocalDerivative(const GeometryContext &gctx, const Vector3 &position) const final

Calculate the derivative of bound track parameters local position w.r.t.

position in local 3D Cartesian coordinates

Return

Derivative of bound local position w.r.t. position in local 3D cartesian coordinates

Parameters

  • gctx: The current geometry context object, e.g. alignment

  • position: The position of the paramters in global

Vector3 localToGlobal(const GeometryContext &gctx, const Vector2 &lposition, const Vector3 &momentum) const final

Local to global transformation.

Return

The global position by value

Parameters

  • gctx: The current geometry context object, e.g. alignment

  • lposition: is the local position to be transformed

  • momentum: is the global momentum (ignored in this operation)

std::string name() const override

Return method for properly formatted output string.

Vector3 normal(const GeometryContext &gctx, const Vector2 &lposition) const final

Return method for surface normal information.

Note

for a Cylinder a local position is always required for the normal vector

Return

normal vector at the local position by value

Parameters

  • gctx: The current geometry context object, e.g. alignment

  • lposition: is the local postion for which the normal vector is requested

Vector3 normal(const GeometryContext &gctx, const Vector3 &position) const final

Return method for surface normal information.

Note

for a Cylinder a local position is always required for the normal vector

Return

normal vector at the global position by value

Parameters

  • gctx: The current geometry context object, e.g. alignment

  • position: is the global postion for which the normal vector is requested

CylinderSurface &operator=(const CylinderSurface &other)

Assignment operator.

Parameters

  • other: is the source cylinder for the copy

double pathCorrection(const GeometryContext &gctx, const Vector3 &position, const Vector3 &direction) const final

Path correction due to incident of the track.

Return

is the correction factor due to incident

Parameters

  • gctx: The current geometry context object, e.g. alignment

  • position: is the global position as a starting point

  • direction: is the global momentum at the starting point

Polyhedron polyhedronRepresentation(const GeometryContext &gctx, size_t lseg) const override

Return a Polyhedron for a cylinder.

Return

A list of vertices and a face/facett description of it

Parameters

  • gctx: The current geometry context object, e.g. alignment

  • lseg: Number of segments along curved lines, it represents the full 2*M_PI coverange, if lseg is set to 1 only the extrema are given

RotationMatrix3 referenceFrame(const GeometryContext &gctx, const Vector3 &position, const Vector3 &momentum) const final

Return the measurement frame - this is needed for alignment, in particular The measurement frame of a cylinder is the tangential plane at a given position.

Return

rotation matrix that defines the measurement frame

Parameters

  • gctx: The current geometry context object, e.g. alignment

  • position: is the position where the measurement frame is defined

  • momentum: is the momentum vector (ignored)

Vector3 rotSymmetryAxis(const GeometryContext &gctx) const

Return method for the rotational symmetry axis.

Return

the z-Axis of transform

Parameters

  • gctx: The current geometry context object, e.g. alignment

SurfaceType type() const override

Return the surface type.

Protected Functions

CylinderSurface(std::shared_ptr<const CylinderBounds> cbounds, const DetectorElementBase &detelement)

Constructor from DetectorElementBase: Element proxy.

Parameters

  • cbounds: are the provided cylinder bounds (shared)

  • detelement: is the linked detector element to this surface

CylinderSurface(const Transform3 &transform, double radius, double halfz, double halfphi = M_PI, double avphi = 0.)

Constructor from Transform3 and CylinderBounds.

Parameters

  • transform: The transform to position the surface

  • radius: The radius of the cylinder

  • halfz: The half length in z

  • halfphi: The half opening angle

  • avphi: The phi value from which the opening angle spans (both sides)

CylinderSurface(const Transform3 &transform, const std::shared_ptr<const CylinderBounds> &cbounds)

Constructor from Transform3 and CylinderBounds arguments.

Parameters

  • transform: The transform to position the surface

  • cbounds: is a shared pointer to a cylindeer bounds object, it must exist (assert test)

CylinderSurface(const CylinderSurface &other)

Copy constructor.

Parameters

  • other: is the source cylinder for the copy

CylinderSurface(const GeometryContext &gctx, const CylinderSurface &other, const Transform3 &shift)

Copy constructor - with shift.

Parameters

  • gctx: The current geometry context object, e.g. alignment

  • other: is the source cone surface

  • shift: is the additional transfrom applied after copying

Protected Attributes

std::shared_ptr<const CylinderBounds> m_bounds

bounds (shared)