Simple Helix. More...

#include <SimpleHelixTrackModel.h>

Public Member Functions
	simpleHelix (const double, const double, const double, const double, const double, const double *, const double)
	Constructor.

	simpleHelix (const double , const double , const double)
	Constructor.

void	dump () const
	Dump helix.

double	getArcLengthXY (const double *) const
	Get (2D) arc length for given point. More...

void	getZSDirection (double *) const
	Get ZS direction (cosLambda, sinLambda).

void	getPosAtArcLength (const double, double *) const
	Get position (on helix) at arc length. More...

bool	getExpectedPlanePos (const double *, const double, double &, double &, double &, double &, double &) const
	Get expected position (and direction) in plane. More...

TMatrixD	analyticalHelixJacobian (const double, const double) const
	Get analytical helix propagator (in constant solenoidal magnetic field) More...

TMatrixD	simplifiedHelixJacobian (const double, const double) const
	Get simplified helix propagator (in constant solenoidal magnetic field) More...

TMatrixD	curvilinearToPerigeeJacobian () const
	Get transformation from curivilinear to perigee track parameters (at reference point) More...

TMatrixD	perigeeToILDJacobian () const
	Get transformation from perigee to L3/ILD track parameters (at reference point) More...

TMatrixD	perigeeToLCIOJacobian () const
	Get transformation from helix to LCIO track parameters (at reference point) More...

TMatrixD	helixToLCIOJacobian () const
	Get transformation from helix to LCIO track parameters (at reference point) More...

void	moveTo (const double, const double, const double, double *)
	Change reference point. More...

void	getStateAt (const double, const double, const double, TMatrixDSym &, TVectorD &, TMatrixDSym &)
	Get state (parameters, covariance matrix) at point. More...

Protected Attributes
const double	_xref
	X of reference point.

const double	_yref
	Y of reference point.

const double	_zref
	Z of reference point.

const double	_bzc
	Z component of magnetic field (*c)

const double	_rinv
	1/R

const double	_phi0
	flight direction at point of closest approach (in XY)

const double	_dca
	distance of closest approach in (XY)

const double	_dzds
	dZ/ds

const double	_z0
	Z position at distance of closest approach.

const double	_xRelCenter
	XY circle parameter: X position of center / R.

const double	_yRelCenter
	XY circle parameter: Y position of center / R.

const double	_eps
	cut off for straight line approximation (\|relevant scale / R\| < _eps)

Detailed Description

Simple Helix.

Utilities for simple helix track model build from perigee parameters, assuming constant magnetic field in Z-direction.

Propagation and transformation jacobians according to Strandlie & Wittek (NIM A 566(2006) 687-698)

Author: C. Kleinwort, DESY (130801)

Member Function Documentation

TMatrixD marlintpc::simpleHelix::analyticalHelixJacobian	(	const double	phi1,
		const double	ds
	)		const

Get analytical helix propagator (in constant solenoidal magnetic field)

For curvilinear track parameters (q/p,lambda,phi,x_t,y_t).

Parameters

[in]	phi1	azimutal direction at start point
[in]	ds	(3D) arc length to end point

Returns: (5*5) propagation matrix

References _bzc, _dzds, _rinv, and marlintpc::localHelixAnalyticalJacobian().

TMatrixD marlintpc::simpleHelix::curvilinearToPerigeeJacobian ( ) const

Get transformation from curivilinear to perigee track parameters (at reference point)

(q/p, lambda, phi, x_t, y_t) -> (kappa, theta, phi, epsilon, z_p)

Returns: (5*5) transformation matrix

References _bzc, _dzds, _phi0, and _rinv.

double marlintpc::simpleHelix::getArcLengthXY ( const double * position ) const

Get (2D) arc length for given point.

Arc length from dca to point on circle on intersection with line from circle center to given point

Parameters

[in] position (XY) Position

Returns: (2D) arc length from dca to point on circle

References _eps, _phi0, _rinv, _xref, _xRelCenter, _yref, and _yRelCenter.

Referenced by marlintpc::tp_PixelSegment::tp_PixelSegment().

bool marlintpc::simpleHelix::getExpectedPlanePos	(	const double *	point,
		const double	measPhi,
		double &	xyPos,
		double &	zPos,
		double &	sArc,
		double &	phi,
		double &	lambda
	)		const

Get expected position (and direction) in plane.

Plane is defined by point and direction in XY and Z axis. Intersection of circle (or straight line) and straight line in XY.

Parameters

[in]	point	point (XYZ) (defining origin of plane)
[in]	measPhi	measurement direction in (XY) plane
[out]	xyPos	position in plane along (XY) measurement direction (relative to point).
[out]	zPos	position in plane along Z direction (relative to point).
[out]	sArc	arc-length at intersection
[out]	phi	phi (flight direction) at intersection
[out]	lambda	lambda (flight direction) at intersection

Returns: success (intersection exists)

References _dca, _dzds, _eps, _phi0, _rinv, _xref, _xRelCenter, _yref, _yRelCenter, _z0, and _zref.

Referenced by marlintpc::rb_Segment::match().

void marlintpc::simpleHelix::getPosAtArcLength	(	const double	sArc,
		double *	position
	)		const

Get position (on helix) at arc length.

Parameters

[in]	sArc	(2D) arc length
[out]	position	(XYZ) Position

References _dca, _dzds, _eps, _phi0, _rinv, _xref, _xRelCenter, _yref, _yRelCenter, _z0, and _zref.

void marlintpc::simpleHelix::getStateAt	(	const double	posX,
		const double	posY,
		const double	posZ,
		TMatrixDSym &	refCov,
		TVectorD &	newPar,
		TMatrixDSym &	newCov
	)

Get state (parameters, covariance matrix) at point.

Parameters

[in]	posX	point (X coordinate)
[in]	posY	point (Y coordinate)
[in]	posZ	point (Z coordinate)
[in]	refCov	covariance matrix at reference point
[out]	newPar	parameter vector at point
[out]	newCov	covariance matrix at point

References _dca, _dzds, _eps, _phi0, _rinv, _xref, _yref, _z0, and _zref.

Referenced by marlintpc::rb_Segment::getLCIOStateAtRefPoint(), marlintpc::tp_PixelSegment::getLCIOStateAtRefPoint(), marlintpc::rb_Segment::match(), marlintpc::tp_PixelSegment::match(), and marlintpc::rb_Segment::rb_Segment().

TMatrixD marlintpc::simpleHelix::helixToLCIOJacobian ( ) const

Get transformation from helix to LCIO track parameters (at reference point)

(rinv, phi0, dca, dzds, z0) -> ( d0, phi0, Omega, z0, tanLambda)

d0 = -dca, phi0 = phi0, omega = -rinv, , z0 = z0, tan(lambda) = dzds

Returns: (5*5) transformation matrix

Referenced by marlintpc::rb_Segment::getLCIOStateAtRefPoint(), and marlintpc::tp_PixelSegment::getLCIOStateAtRefPoint().

void marlintpc::simpleHelix::moveTo	(	const double	newRefX,
		const double	newRefY,
		const double	newRefZ,
		double *	newPar
	)

Change reference point.

Parameters

[in]	newRefX	new reference point (X coordinate)
[in]	newRefY	new reference point (Y coordinate)
[in]	newRefZ	new reference point (Z coordinate)
[out]	newPar	new helix parameter array[5]

References _dca, _dzds, _eps, _phi0, _rinv, _xref, _yref, _z0, and _zref.

TMatrixD marlintpc::simpleHelix::perigeeToILDJacobian ( ) const

Get transformation from perigee to L3/ILD track parameters (at reference point)

(kappa, theta, phi, epsilon, z_p) -> (omega, tan(lambda), phi, d0, z0)

omega = -kappa, lambda = pi/2 - theta, d0 = -epsilon, z0 = z_p

Returns: (5*5) transformation matrix

References _dzds.

TMatrixD marlintpc::simpleHelix::perigeeToLCIOJacobian ( ) const

Get transformation from helix to LCIO track parameters (at reference point)

(kappa, theta, phi, epsilon, z_p) -> ( d0, phi0, Omega, z0, tanLambda)

d0 = -epsilon, phi0 = phi, omega = -kappa, , z0 = z_p, lambda = pi/2 - theta

Returns: (5*5) transformation matrix

References _dzds.

TMatrixD marlintpc::simpleHelix::simplifiedHelixJacobian	(	const double	phi1,
		const double	ds
	)		const

Get simplified helix propagator (in constant solenoidal magnetic field)

Parabola with curvilinear track parameters (q/p,lambda,phi,x_t,y_t).

Parameters

[in]	phi1	azimutal direction at start point
[in]	ds	(3D) arc length to end point

Returns: (5*5) propagation matrix

References _bzc, and _dzds.

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

SimpleHelixTrackModel.h
SimpleHelixTrackModel.cc

Public Member Functions

Protected Attributes

Detailed Description

Member Function Documentation