marlintpc::StepWiseHelixGeneralBrokenLineInterfaceProcessor Class Reference

Using GBL with a step-wise helix. More...

#include <StepWiseHelixGeneralBrokenLineInterfaceProcessor.h>

Inheritance diagram for marlintpc::StepWiseHelixGeneralBrokenLineInterfaceProcessor:

Public Member Functions
virtual Processor *	newProcessor ()
virtual void	init ()
virtual void	processRunHeader (EVENT::LCRunHeader *run)
virtual void	processEvent (EVENT::LCEvent *evt)
virtual void	check (EVENT::LCEvent *evt)
virtual void	end ()

Protected Attributes
std::string	_inputCollectionName
	Name of the input collection – track seeds.
std::string	_outputTrackCollectionName
	Name of the output track collection.
double	_bfieldScaleFactor
	scale factor for magnetic field (default: 1.0)
bool	_outputIsPersistent
	whether the output is to be stored or not (default: true)
std::string	_fitOptions
	list of iterations with 'h' Huber, 't' Tukey or 'c' Cauchy down-weighting
bool	_writeMillepedeOut
	selects output to Millepede-II binary file
std::string	_fileNameMillepedeFile
	name of Millepede-II binary file
int	_milleCalcMethod
	defines which parameter should be calculated for Millepede-II binary file
int	_milleMinHits
	defines minimum number of hits on track for output to Millepede binary file
bool	_encodedModuleID
	Module ID is encoded in CellID0.
double	_maxStep
	maximal step size (default: 10.)
double	_x0PerUnitLength
	X0 per unit length (TPC gas as homogeneous scatterer) (default: 0.)
bool	_thickScatterer
	selects thick (otherwise thin) scatterers for multiple scattering (default: false)
double	_defaultMomentum
	default momentum for multiple scattering (for Bfield off, GeV) (default: 10.)

Detailed Description

Using GBL with a step-wise helix.

Processor interface to step-wise helix (or line) fitting with General Broken Lines, written by Claus Kleinwort

Author

C. Kleinwort, DESY

This processor interfaces the re-fitting functionality of the general broken line package by Claus Kleinwort. For information on the General Broken Lines, please refer to the publication and/or the wiki pages:

• C. Kleinwort, General Broken Lines as advanced track fitting method, NIM A, 673 (2012), 107-110, doi:10.1016/j.nima.2012.01.024
• http://www.wiki.terascale.de/index.php/GeneralBrokenLines

The standard behaviour is that a single, straightforward fit without any outlier rejection is performed. For multiple turns, including some outlier rejection; extend the fit options in the according steering parameter. The calculation of the measurement (pad) direction in XY uses "module.getLocalPadLayout().getCoordinateType()" to select polar or cartesian pad row geometry.

Inputs and requirements

• Input to the processor are the found tracks with their associated hits (with the reference point inside the magnetic field!).
• The curvilinear system is used as local system at each hit.
• The curvilinear track parameters are used as local parameters at each hit.
• A form of hit cleaning should be performed before calling the fit – before using the fit results.

Output

• Output are the fitted tracks with the best estimation of track parameters and their uncertainties.
• The specific energy loss is estimated from the median (and the MAD) of the 1/sqrt(E_scaled) distribution.
• Optional output is a Millepede-II binary file, which can be inspected

Parameters

"InputSeedTracks":string	The name of the input collection of track candidates (default: "TPCSeedTracks")
"OutputTracks":string	The name of the output collection with the fitted tracks(default: "TPCTracks")
"WriteOutputToStorage":bool	To set whether the output should be written to storage
"BFieldScaleFactor":double	Optional parameter, scales magnetic field (map), use 1.0 (default) for field ON or 0.0 for field OFF
"FitOptions":string	Optional parameter, defines if multiple passes with "h" huber, "t" tukey or "c" cauchy downweighting should be performed
"WriteMillepedeBinary":bool	Optional parameter, set to "true" if you want a Millepede binary file (default:"false")
"MillepedeFilename":string	Optional parameter to set the name of the Millepede binary file (default:"")
"MillePedeCalcMethod":int	Optional parameter to define set of (global) parameters (default:0 = module alignment)
"MillePedeMinHits":int	Optional parameter to define the minimum number of hits on track for output to Millepede binary file (default: 42)
"EncodedModuleID":bool	Optional parameter, flag for encoding of module ID in CellID0 (default true)
"MaxStep":double	Optional parameter, maximal step size (with constant magnetic field) (default 10.0)
"X0PerUnitLength":double	Optional parameter, X0 per unit length (TPC gas as homogeneous scatterer) (default: 0.)
"ThickScatterer":bool	Optional parameter, selects thick (otherwise thin) scatterers for multiple scattering (default: false)
"DefaultMomentum":double	Optional parameter, default momentum for multiple scattering (for Bfield off, GeV) (default: 10.)

WORK IN PROGRESS: currently only works for modules with concentric pad rows (using center from GEAR)

Todo:

• implement additional output of pull distributions, residuals, track paramters for each measurement point

A detailed description is available as lcnote LC-TOOL-2014-008. Changes with respect to this note:

• Additional parameter "MillePedeMinHits" for help class "trackerAlcaSelector"
• 160223 CHK: Implement TPC gas as homogeneous scatterer (between first and last hit) modelled by thin or thick scatterers (per hit)

---

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

• StepWiseHelixGeneralBrokenLineInterfaceProcessor.h