StiKalmanTrackNode Class Reference

#include <StiKalmanTrackNode.h>

Inheritance diagram for StiKalmanTrackNode:

List of all members.

Public Member Functions
	StiKalmanTrackNode (const StiKalmanTrackNode &node)
const StiKalmanTrackNode &	operator= (const StiKalmanTrackNode &node)
void	reset ()
	Resets the node to a "null" un-used state.
void	unset ()
void	resetError (double fak=0)
	Resets errors for refit.
void	initialize (StiHit *h)
	Initialize this node with the given hit information.
void	initialize (StiDetector *d)
void	setState (const StiKalmanTrackNode *node)
	Sets the Kalman state of this node equal to that of the given node.
void	get (double &alpha, double &xRef, double x[kNPars], double cc[kNErrs], double &chi2)
	Extract state information from this node.
void	getGlobalRadial (double x[6], double e[15])
	Extract state information from this node in Radial representation.
void	getGlobalTpt (float x[6], float e[15])
	Extract state information from this node in TPT representation.
int	getCharge () const
	Get the charge (sign) of the track at this node.
StThreeVectorF	getMomentumF () const
	Convenience Method that returns the track momentum at this node.
StThreeVectorF	getGlobalMomentumF () const
StThreeVector< double >	getMomentum () const
StThreeVector< double >	getGlobalMomentum () const
void	getMomentum (double p[3], double e[6]=0) const
double	getCurvature () const
	Calculates and returns the tangent of the track pitch angle at this node.
void	setCurvature (double curvature)
double	getDipAngle () const
double	getTanL () const
double	getPt () const
	Calculates and returns the transverse momentum of the track at this node.
double	getP () const
	Calculates and returns the momentum of the track at this node.
double	getHz () const
double	getField () const
double	x_g () const
double	y_g () const
double	z_g () const
void	getXYZ_g (double *xyz) const
double	getX () const
double	getY () const
double	getZ () const
double	x () const
double	y () const
double	z () const
double	getRxy () const
double	getEta () const
double	getSin () const
double	getCos () const
double	getAlpha () const
const double *	hitErrs () const
double	getEyy () const
double	getEzz () const
double	getCyy () const
double	getCzz () const
double const *	getPars () const
double	getDiag (int idx) const
int	getHitCount () const
int	getNullCount () const
int	getContigHitCount () const
int	getContigNullCount () const
int	incHitCount ()
int	incNullCount ()
int	incContigHitCount ()
int	incContigNullCount ()
void	setHitCount (char c=0)
void	setNullCount (char c=0)
void	setContigHitCount (char c=0)
void	setContigNullCount (char c=0)
double	getTime () const
void	setHitCand (int nhits)
void	setIHitCand (int ihit)
int	getHitCand () const
int	getIHitCand () const
StThreeVector< double >	getPoint () const
StThreeVector< double >	getGlobalPoint () const
void	getGlobalMomentum (double p[3], double e[6]=0) const
	Calculates and returns the momentum and error of the track at this node in global coordinates.
int	isEnded () const
int	isDca () const
int	propagate (StiKalmanTrackNode *p, const StiDetector *tDet, int dir)
	Propagates a track encapsulated by the given node "p" to the given detector "tDet".
bool	propagate (const StiKalmanTrackNode *p, StiHit *vertex, int dir)
	Propagates a track encapsulated by the given node "p" to the given vertex.
bool	propagateToBeam (const StiKalmanTrackNode *p, int dir)
int	propagateToRadius (StiKalmanTrackNode *pNode, double radius, int dir)
double	evaluateDedx ()
int	locate ()
int	propagate (double x, int option, int dir)
void	propagateMtx ()
void	propagateError ()
void	saveInfo (int kase=1)
const StiNodeInf *	getInfo () const
int	testError (double *emx, int begend)
void	numeDeriv (double val, int kind, int shape=0, int dir=0)
int	testDeriv (double *der)
void	propagateMCS (StiKalmanTrackNode *previousNode, const StiDetector *tDet)
StThreeVector< double >	getPointAt (double xk) const
int	nudge (StiHit *hit=0)
double	evaluateChi2 (const StiHit *hit)
int	updateNode ()
int	rotate (double alpha)
int	getHelicity () const
double	getPhase () const
double	getPsi () const
double	getWindowY ()
double	getWindowZ ()
double	pitchAngle () const
double	crossAngle () const
double	sinCrossAngle () const
double	pathlength () const
double	pathLToNode (const StiKalmanTrackNode *const oNode)
StThreeVectorD *	getLengths (StiKalmanTrackNode *nextNode)
double	length (const StThreeVector< double > &delta, double curv)
double	getDedx () const
StThreeVector< double >	getHelixCenter () const
	Return center of helix circle in global coordinates.
void	setHitErrors (const StiHit *hit=0)
StiHitErrs	getGlobalHitErrs (const StiHit *hit) const
double	getX0 () const
double	getGasX0 () const
double	getDensity () const
double	getGasDensity () const
void	extend ()
void	reduce ()
void	PrintpT (const Char_t *opt="") const
int	getFlipFlop () const
int	print (const char *opt) const
	rotation angle of local coordinates wrt global coordinates
const StiNodePars &	fitPars () const
StiNodePars &	fitPars ()
const StiNodeErrs &	fitErrs () const
StiNodeErrs &	fitErrs ()
const StiNodePars &	mPP () const
StiNodePars &	mPP ()
const StiNodeErrs &	mPE () const
StiNodeErrs &	mPE ()
const StiNodeMtx &	mMtx () const
StiNodeMtx &	mMtx ()
const StiNode2Pars &	unTouched () const
void	setUntouched ()
Static Public Member Functions
static double	mcs2 (double relRadThickness, double beta2, double p2)
static void	Break (int kase)
static void	PrintStep ()
static double	nice (double angle)
static Int_t	debug ()
static void	setDebug (Int_t m)
static void	SetLaser (Int_t m)
static Int_t	IsLaser ()
static void	ResetComment (const Char_t *m="")
static const Char_t *	Comment ()
Public Attributes
int	mId
Protected Attributes
char	_beg [1]
double	_alpha
double	mHz
	Z mag field in units PGev = Hz*Rcm.
StiNodePars	mFP
StiNodeErrs	mFE
	covariance matrix of the track parameters
StiNode2Pars	mUnTouch
StiHitErrs	mHrr
char	hitCount
char	nullCount
char	contiguousHitCount
char	contiguousNullCount
char	mFlipFlop
char	mHitCand
char	mIHitCand
char	_end [1]
StiNodeExt *	_ext
StiNodeInf *	_inf
Static Protected Attributes
static StiNodeStat	mgP
static bool	useCalculatedHitError = true
static int	fDerivTestOn = -10
static double	fDerivTest [kNPars][kNPars]
static int	_debug = 0
static TString	comment
static TString	commentdEdx
static int	_laser = 0
Friends
class	StiTrackNodeHelper
ostream &	operator<< (ostream &os, const StiKalmanTrackNode &n)

---

Detailed Description

Work class used to handle Kalman filter information while constructing track nodes. A node may or may not own a hit depending whether it lies on a measurement layer where a hit was found. A node can have 0, 1, or many children. Nodes are nominally sequenced outside-in i.e. with decreasing radius (or independent variable). The order can however be reversed. In anycase, the order should always be monotonically increasing or decreasing.

Author:

Claude A Pruneau

Definition at line 76 of file StiKalmanTrackNode.h.

---

Member Function Documentation

double StiKalmanTrackNode::evaluateChi2

(

const StiHit *

hit

)

Calculate the increment of chi2 caused by the addition of this node to the track.

Uses the track extrapolation to "_x", and hit position to evaluate and return the increment to the track chi2. The chi2 is not stored internally in this node.

Notes

1. Use full error matrices.
2. Return increment in chi2 implied by the node/hit assocition.
3. Throws an exception if numerical problems arise.

Definition at line 1274 of file StiKalmanTrackNode.cxx.

References mFE, and StiHit::x().

Referenced by StiKalmanTrack::extendToVertex(), and StiKalmanTrackFitter::fit().

double StiKalmanTrackNode::evaluateDedx

(

)

Evaluates, stores and returns the dedx associated with this node. Possible returned values are: > 0 : value of dedx -1 : pathlength was invalid or less than "0" -2 : no hit is associated with the node. -3 : invalid eloss data for this node.

void StiKalmanTrackNode::get	(	double &	alpha,
		double &	xRef,
		double	x[kNPars],
		double	e[kNErrs],
		double &	chi2
	)

Extract state information from this node.

returns the node information double& alpha : angle of the local reference frame double& xRef : refence position of this node in the local frame double x[6], : state, for a definition, see the top of this file double cc[21] : error matrix of the state "x" double& chi2) : chi2 of the track at this node

Definition at line 552 of file StiKalmanTrackNode.cxx.

References mFE.

double StiKalmanTrackNode::getGasX0

(

)

const [inline]

Return the radiation length (in cm) of the gas surrounding the detector volume at this node.

Definition at line 391 of file StiKalmanTrackNode.h.

Referenced by StiKalmanTrack::getTrackRadLength(), and propagateMCS().

void StiKalmanTrackNode::getGlobalMomentum	(	double	p[3],
		double	e[6] = 0
	)			const

Calculates and returns the momentum and error of the track at this node in global coordinates.

returns momentum and its error matrix in cartesian coordinates in the _global_ ref frame of the experiment p[0] = px p[1] = py p[2] = pz Use lower triangular matrix e[0] = px-px e[1] = px-py e[2] = py-py e[3] = px-pz e[4] = py-pz e[5] = pz-pz

Definition at line 807 of file StiKalmanTrackNode.cxx.

StThreeVectorF StiKalmanTrackNode::getGlobalMomentumF

(

)

const [inline]

Convenience Method that returns the track momentum at this node in global coordinates.

Definition at line 345 of file StiKalmanTrackNode.h.

References getMomentumF().

void StiKalmanTrackNode::getGlobalRadial	(	double	x[6],
		double	e[15]
	)

Extract state information from this node in Radial representation.

returns the node information double x[6], : state, for a definition, in radial implementation rad - radius at start (cm). See also comments phi - azimuthal angle (in rad) z - z-coord. (cm) psi - azimuthal angle of pT vector (in rads) tanl - tan(dip) =pz/pt curv - Track curvature (1/cm) double cc[15] : error matrix of the state "x" rad is fixed code definition adopted here, where: PhiPhi; ZPhi ,ZZ; TanlPhi ,TanlZ ,TanlTanl, PsiPhi ,PsiZ ,PsiTanl , PsiPsi , CurvPhi ,CurvZ ,CurvTanl, CurvPsi, CurvCurv

Definition at line 686 of file StiKalmanTrackNode.cxx.

References mFE.

Referenced by getGlobalTpt().

void StiKalmanTrackNode::getGlobalTpt	(	float	x[6],
		float	e[15]
	)

Extract state information from this node in TPT representation.

returns the node information in TPT representation double x[6], : state, for a definition, in radial implementation rad - radius at start (cm). See also comments phi - azimuthal angle (in rad) z - z-coord. (cm) psi - azimuthal angle of pT vector (in rads) tanl - tan(dip) =pz/pt q/pt - double cc[15] : error matrix of the state "x" rad is fixed code definition adopted here, where:

Units ______|________________|____________ phi*R | 0 1 2 3 4 | deg*cm z0 | 1 5 6 7 8 | cm tanl | 2 6 9 10 11 | 1 covar(i) psi | 3 7 10 12 13 | deg q/pt | 4 8 11 13 14 | e*1/(GeV/c) -----------------------------------

and where phi = atan2(y0,x0)*(180 deg/pi) R = sqrt(x0*x0 + y0*y0) q/pt = icharge*invpt; (This is what the radius of curvature actually determines) PhiPhi PhiZ PhiTan PhiPsi PhiPt ZZ ZTan ZPsi ZPt TanTan TanPsi TanPt PsiPsi PsiPt PtPt

Definition at line 755 of file StiKalmanTrackNode.cxx.

References getCharge(), getGlobalRadial(), and getPt().

double StiKalmanTrackNode::getHz

(

)

const

Calculates and returns the Z mag field in the current point. units: PGeV = Hz*Radcurv_in_CM

Calculate/return the z component of mag field

Calculate/return the z component of mag field

Field is calcualated via StarMagField class and cashed.

Definition at line 592 of file StiKalmanTrackNode.cxx.

References mHz.

Referenced by initialize(), propagate(), propagateMCS(), propagateMtx(), and updateNode().

void StiKalmanTrackNode::getMomentum	(	double	p[3],
		double	e[6] = 0
	)			const

Calculates and returns the momentum and error of the track at this node. The momentum is in the local reference frame of this node.

Calculate/return track 3-momentum and error.

Calculate the 3-momentum of the track in the local reference frame.

Momentum Representation

p[0]	px	outward
p[1]	py	along detector plane
p[2]	pz	along beam direction

Notes:

1. Throws runtime_error exception if |sin(phi)^2|>1.
2. Bypasses error calculation if error array "e" is a null pointer.

Definition at line 635 of file StiKalmanTrackNode.cxx.

References getPt(), and mFE.

double StiKalmanTrackNode::getPhase

(

)

const

This function translates between ITTF helix parameters and StHelixModel phi. It is only used to fill StTrackGeometry. For a StPhysicalHelix, phi must be transformed by -h*pi/2.

Definition at line 777 of file StiKalmanTrackNode.cxx.

Referenced by StiKalmanTrack::getDca(), and StiKalmanTrack::getNearBeam().

StThreeVector<double> StiKalmanTrackNode::getPointAt

(

double

xk

)

const

Extrapolate the track parameters to radial position "x" and return a point global coordinates along the track at that point.

double StiKalmanTrackNode::getPt

(

)

const

Calculates and returns the transverse momentum of the track at this node.

Calculate/return the track transverse momentum

Calculate the track transverse momentum in GeV/c based on this node's track parameters.

The momentum is calculated based on the track curvature held by this node. A minimum curvature of 1e-12 is allowed.

Definition at line 574 of file StiKalmanTrackNode.cxx.

Referenced by getGlobalTpt(), getMomentum(), getMomentumF(), getP(), StiKalmanTrack::getPt(), and propagateMCS().

double StiKalmanTrackNode::getX0

(

)

const [inline]

Return the radiation length (in cm) of the the detector volume at this node.

Definition at line 381 of file StiKalmanTrackNode.h.

Referenced by StiKalmanTrack::getTrackRadLength(), and propagateMCS().

double StiKalmanTrackNode::pathlength

(

)

const [inline]

Calculate and returns pathlength within detector volume associated with this node. Returns 0 if no detector is associated.

Definition at line 371 of file StiKalmanTrackNode.h.

Referenced by StiKalmanTrack::getTrackRadLength(), and propagateMCS().

double StiKalmanTrackNode::pathLToNode

(

const StiKalmanTrackNode *const

oNode

)

Calculate the effect of MCS on the track error matrix.

The track is assumed to propagate from (x0,y0,z0) to (mgP.x1,y1,z1). The calculation is performed for the given mass hypothesis which given a momentum determines the speed "beta" of the particle. The calculation of the average scattering angle is delegated to the function "mcs2". The calculation of energy loss is done by the function eloss.

Calulates length between center of this node and provided node, which is assumed to be on the same helix. Have to use global coords, since nodes may not be in the same detector volume.

Returns:

(double) length

Definition at line 1239 of file StiKalmanTrackNode.cxx.

References getCurvature().

Referenced by StiKalmanTrack::getTrackRadLength(), and propagateMCS().

int StiKalmanTrackNode::propagate	(	double	xk,
		int	option,
		int	dir
	)

Work method used to perform the tranport of "this" node from its current "_x" position to the given position "xk". Returns -1 if the propagation cannot be carried out, i.e. if the track curvature is such it cannot reach the desired location. option == 0 Planar option == 1 Cylinder

Definition at line 988 of file StiKalmanTrackNode.cxx.

References getHz().

bool StiKalmanTrackNode::propagate	(	const StiKalmanTrackNode *	parentNode,
		StiHit *	vertex,
		int	dir
	)

Propagates a track encapsulated by the given node "p" to the given vertex.

Propagate the track encapsulated by pNode to the given vertex. Use this node to represent the track parameters at the vertex.

This method propagates the track from the given parent node "pNode" to the given vertex effectively calculating the location (x,y,z) of the track near the given vertex. It use "this" node to represent/hold the track parameters at the vertex. return true when the propagation is successfull and false otherwise.

Definition at line 921 of file StiKalmanTrackNode.cxx.

References propagate(), propagateError(), rotate(), StiHit::rotate(), setState(), and StiHit::x().

int StiKalmanTrackNode::propagate	(	StiKalmanTrackNode *	pNode,
		const StiDetector *	tDet,
		int	dir
	)

Propagates a track encapsulated by the given node "p" to the given detector "tDet".

Steering routine that propagates the track encapsulated by the given node "pNode" to the given detector "tDet".

The propagation involves the following steps.

1. Extrapolation of the existing track to the next layer, by "transporting" the track a smaller radius.
2. Determine if the extrapolation actually intersects an existing volume.
3. Exit with status code if no intersection is found.
4. Transport the error matrix to the new radius.
5. If mcsCalculated==true, proceed to calculate MCS effects on the error matrix.
6. if elossCalculated==true, proceed to calculate Eloss effects on the track parameters.

Currently, propagate can handle kPlanar and kCylindrical geometries only. An exception is thrown if other geometry shape are used.

Definition at line 855 of file StiKalmanTrackNode.cxx.

References getHz(), Named::getName(), propagateError(), propagateMCS(), rotate(), and setState().

Referenced by StiKalmanTrack::extendToVertex(), StiKalmanTrackFitter::fit(), StiKalmanTrack::getMomentumAtOrigin(), propagate(), propagateToBeam(), and propagateToRadius().

void StiKalmanTrackNode::propagateError

(

)

Propagate the track error matrix

Note:

This method must be called ONLY after a call to the propagate method.

Definition at line 1166 of file StiKalmanTrackNode.cxx.

References mFE, and propagateMtx().

Referenced by propagate(), propagateToBeam(), and propagateToRadius().

void StiKalmanTrackNode::propagateMCS	(	StiKalmanTrackNode *	previousNode,
		const StiDetector *	tDet
	)

Calculate the effect of MCS on the track error matrix.

The track is assumed to propagate from (x0,y0,z0) to (x1,y1,z1). The calculation is performed for the given mass hypothesis which given a momentum determines the speed "beta" of the particle. The calculation of the average scattering angle is delegated to the function "mcs2". The calculation of energy loss is done by the function eloss.

Definition at line 1346 of file StiKalmanTrackNode.cxx.

References getGasX0(), getHz(), getPt(), getX0(), mFE, pathlength(), and pathLToNode().

Referenced by propagate().

void StiKalmanTrackNode::propagateMtx

(

)

Make propagation matrix

Note:

This method must be called ONLY after a call to the propagate method.

Definition at line 1120 of file StiKalmanTrackNode.cxx.

References getHz().

Referenced by propagateError().

bool StiKalmanTrackNode::propagateToBeam	(	const StiKalmanTrackNode *	parentNode,
		int	dir
	)

Propagate track from the given node to the beam line with x==0. Set the hit and detector pointers to null to manifest this is an extrapolation

Definition at line 945 of file StiKalmanTrackNode.cxx.

References propagate(), propagateError(), and setState().

Referenced by StiKalmanTrack::extrapolateToBeam().

int StiKalmanTrackNode::propagateToRadius	(	StiKalmanTrackNode *	pNode,
		double	radius,
		int	dir
	)

Extrapolate the track defined by the given node to the given radius. Return a negative value if the operation is impossible.

Definition at line 964 of file StiKalmanTrackNode.cxx.

References propagate(), propagateError(), and setState().

int StiKalmanTrackNode::rotate

(

double

alpha

)

Rotate this node track representation azymuthally by given angle.

This method rotates by an angle alpha the track representation held by this node.

Notes

1. The rotation is bound between -M_PI and M_PI.
2. Throws runtime_error if "(_y-y0)*_curv>=0" in order to avoid math exception.
3. Avoid undue rotations as they are CPU intensive...

Definition at line 1660 of file StiKalmanTrackNode.cxx.

References mFE.

Referenced by StKFVertexMaker::Make(), and propagate().

void StiKalmanTrackNode::setState

(

const StiKalmanTrackNode *

n

)

Sets the Kalman state of this node equal to that of the given node.

Set the Kalman state of this node to be identical to that of the given node. This method is useful to initial the state of a node while propagating a track.

Definition at line 530 of file StiKalmanTrackNode.cxx.

References mFE.

Referenced by propagate(), propagateToBeam(), and propagateToRadius().

int StiKalmanTrackNode::updateNode

(

)

Update the track parameters using this node.

This method uses the hit contained by node to update the track parameters contained by this node and thus complete the propagation of this track to the location x=_x.

1. Throw a runtime_error exception if no hit is actually associated with this node.
2. Compute the measurement error matrix "r". Invert it.
3. Update the measurement matrix "k" and calculate updated curvature, eta, and pitch.
4. Update track error matrix.

Notes

1. Throw logic_error if no hit is associated with this node.
2. Throw runtime_error if determinent of "r" matrix is null.

Definition at line 1486 of file StiKalmanTrackNode.cxx.

References getHz(), and mFE.

Referenced by StiKalmanTrack::extendToVertex().

---

Friends And Related Function Documentation

ostream& operator<<	(	ostream &	os,
		const StiKalmanTrackNode &	n
	)			[friend]

print to the ostream "os" the parameters of this node and all its children recursively

Definition at line 1709 of file StiKalmanTrackNode.cxx.

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The documentation for this class was generated from the following files:

• Sti/StiKalmanTrackNode.h
• Sti/StiKalmanTrackNode.cxx