#include <StiHit.h>

Public Types
enum	StiHitProperty { kR, kZ, kPseudoRapidity, kPhi }

Public Member Functions
	StiHit ()
	Default constructor.

	StiHit (const StiHit &)

const StiHit &	operator= (const StiHit &)

	~StiHit ()
	Default destructor.

const Float_t &	x () const
	Return the local x, y, z values.

const Float_t &	y () const

const Float_t &	z () const

const Float_t	y (Float_t time) const

const Float_t	z (Float_t time) const

Float_t	x_g () const
	Return the global x, y, z values.

Float_t	y_g () const

Float_t	z_g () const

float	rxy () const
	Return the rxy.

Float_t	sxx () const
	Return components of the error matrix.

Float_t	syy () const

Float_t	szz () const

Float_t	sxy () const

Float_t	sxz () const

Float_t	syz () const

const Float_t *	errMtx () const

Float_t	getEloss ()
	Return the energy deposition associated with this point.

Float_t	refangle () const
	Return the refAngle of the detector plane from which the hit arose.

Float_t	position () const
	Return the position of the detector plane from which the hit arose.

const StiDetector *	detector () const

Int_t	isDca () const
	Test for DCA. Fake hit for dca calculation.

void	makeDca ()
	Make fake hit for dca calculation.

const StMeasuredPoint *	stHit () const

UInt_t	timesUsed () const
	Return the number of times this hit was assigned to a track.

const StThreeVectorF	globalPosition () const

void	set (Float_t position, Float_t angle, Float_t y, Float_t z)

void	set (const StiDetector detector, const StMeasuredPoint stHit, Float_t energy, Float_t x, Float_t y, Float_t z, Float_t sxx=1, Float_t sxy=1, Float_t sxz=1, Float_t syy=1, Float_t syz=1, Float_t szz=1)
	Set the local position and error in one function call.

void	setGlobal (const StiDetector detector, const StMeasuredPoint stHit, Float_t x, Float_t y, Float_t z, Float_t energy)

void	setError (const StMatrixF &)

void	setError (const Float_t errMx[6])

void	setDetector (const StiDetector *det)
	Set the pointer to the StiDetector from which the hit arose.

void	setStHit (const StMeasuredPoint *hit)
	Set the pointer to the corresponding StHit object.

void	setMaxTimes (int set)
	Set the number of times used.

void	setTimesUsed (int set)

void	addTimesUsed ()
	???

void	subTimesUsed ()

int	isUsed () const

void	setVz (Float_t vz)

void	setVy (Float_t vy)

void	reset ()

void	unset ()

void	rotate (double angle)

double	getValue (Int_t key) const

double	getPseudoRapidity () const

Float_t	vz () const

Float_t	vy () const

int	idTruth () const

int	qaTruth () const

Public Attributes
Int_t	mCount

Protected Attributes
char	mBeg [1]

char	mMaxTimes

char	mTimesUsed

Float_t	mrefangle

Float_t	mposition

Float_t	mx

Float_t	my

Float_t	mz

Float_t	msxx

Float_t	msxy

Float_t	msyy

Float_t	msxz

Float_t	msyz

Float_t	mszz

Float_t	_xg

Float_t	_yg

Float_t	_zg

const StiDetector *	mdetector

const StMeasuredPoint *	msthit

Float_t	_energy

Float_t	_vy

Float_t	_vz

char	mEnd [1]

Friends
ostream &	operator<< (ostream &os, const StiHit &h)

Detailed Description

StiHit is a simple class that encapsulates a three dimensional position measurement. The measurement is represented in a frame that is 'local' to the detector plane from which it arose.

It is assumed that all hits come from a detector that can be composed of discrete planes. Each plane is characterized by two values: position and refAngle. In the mid-rapidity region of STAR (SVT, TPC, EMC, etc) the position corresponds to the magnitude of a vector pointing from the origin to the center of the plane. The refAngle is the azimuthal defined by the aforemention vector and the STAR global x-axis. All hits store the position and refAngle of the detector plane from which they came.

Within each detector plane, the hit is characterized by two more numbers: y and z. The y value corresponds to the distance along the plane (e.g., padrow) w.r.t. the center of the plane. The z value corresponds to the STAR global coordinate.

While it only takes two values (y and z) two specify the hit location within a plane (once the location of the plane is known) StiHit stores one more value: x. This value of x corresponds to the magnitude of a vector pointing from the origin to the detector plane perpendicular to the plane. So, for planes with no tilt w.r.t. the origin (e.g., TPC pad-planes), x will be identical to position. Actually, this is not even quite true for tpc hits, as distortion corrections can make x slightly different than position. However, by storing both x and position, we allow for the separation of information that depends only on material location (track fitting) from that which depends only on hit location (track finding).

StiHit stores information that represents a full error matrix. For efficiency purposes this is stored as a collection of discreet floats instead of a matrix. Because the error matrix is always symmetric, we must store only six values. These are denoted by s_ij, where s_ij corresponds to the (i,j) component of the matrix.

StiHit also stores a pointer to an StHit that it corresponds to. Additionally, StiHit stores a pointer to the StDetector object from which its measurement arose.

Author: M.L. Miller (Yale Software)

Definition at line 51 of file StiHit.h.

Member Function Documentation

const StiDetector* StiHit::detector ( ) const

inline

Return a const pointer to the StiDetector object from which the hit arose.

Definition at line 96 of file StiHit.h.

Referenced by StiDetectorBuilder::add(), StiHitContainer::add(), StiLocalTrackSeedFinder::extendHit(), StiLocalTrackSeedFinder::extrapolate(), StiStEventFiller::fillDetectorInfo(), StiKalmanTrack::getFitPointCount(), StiHitContainer::getHits(), StiKalmanTrack::getNodes(), StiHftHits::hftHist(), StiKalmanTrackNode::initialize(), StiKalmanTrack::initialize(), setGlobal(), and StiKalmanTrack::stHits().

const StThreeVectorF StiHit::globalPosition ( ) const

Return a const reference to a StThreeVectorF that denotes the position of the hit in global STAR coordinates.

Definition at line 259 of file StiHit.cxx.

int StiHit::isUsed ( ) const

inline

Return a boolean that marks whether or not this hit is assigned to a track >= than max times.

Definition at line 148 of file StiHit.h.

Referenced by StiHitContainer::getHits().

void StiHit::rotate ( double alpha )

Convenience method to perform a rotation along the z axis

Definition at line 46 of file StiHit.cxx.

References TCL::trasat(), and x().

Referenced by StiKalmanTrack::extendToVertex(), and StiKalmanTrackNode::propagate().

void StiHit::setError ( const StMatrixF & matrix )

Set the position error matrix for the measurement from an StMatrixF object.

Definition at line 67 of file StiHit.cxx.

References x().

void StiHit::setError ( const Float_t errMx[6] )

Set the position error matrix for the measurement from an Float_t array object.

void StiHit::setGlobal	(	const StiDetector *	detector,
		const StMeasuredPoint *	stHit,
		Float_t	x,
		Float_t	y,
		Float_t	z,
		Float_t	energy
	)

Set the global position and error in one function call A transformation is performed internally from global to local coordinates according to the detector information.

Definition at line 133 of file StiHit.cxx.

References StiDetector::_cos, StiDetector::_sin, detector(), Named::getName(), and stHit().

Referenced by StKFVertexMaker::Make().

const StMeasuredPoint* StiHit::stHit ( ) const

inline

Return a const pointer to the StHit object corresponding to this StiHit instance

Definition at line 104 of file StiHit.h.

Referenced by StiStEventFiller::fillDetectorInfo(), StiCATpcSeedFinder::findTrack(), setGlobal(), and StiKalmanTrack::stHits().