DDSpacePointBuilder Class Reference

================= FTD Space Point Builder ================= More...

#include <DDSpacePointBuilder.h>

Inheritance diagram for DDSpacePointBuilder:

Public Member Functions
virtual Processor *	newProcessor ()
virtual void	init ()
	Called at the begin of the job before anything is read. More...
virtual void	processRunHeader (LCRunHeader *run)
	Called for every run.
virtual void	processEvent (LCEvent *evt)
	Called for every event - the working horse.
virtual void	check (LCEvent *evt)
virtual void	end ()
	Called after data processing for clean up.

Protected Member Functions
TrackerHitImpl *	createSpacePoint (TrackerHitPlane *a, TrackerHitPlane *b, double stripLength)
std::vector< int >	getCellID0sAtBack (int cellID0)
std::vector< int >	getCellID0sAtBackOfFTD (int cellID0)
std::vector< int >	getCellID0sAtBackOfSET (int cellID0)
std::vector< int >	getCellID0sAtBackOfSIT (int cellID0)
std::string	getCellID0Info (int cellID0)

Static Protected Member Functions
static int	calculateXingPoint (double x1, double y1, float ex1, float ey1, double x2, double y2, float ex2, float ey2, double &x, double &y)
	Calculates the 2 dimensional crossing point of two lines. More...
static int	calculatePointBetweenTwoLines (const CLHEP::Hep3Vector &P1, const CLHEP::Hep3Vector &V1, const CLHEP::Hep3Vector &P2, const CLHEP::Hep3Vector &V2, CLHEP::Hep3Vector &point)
	Calculates a point between two lines in a way that it is equidistant from both lines and as close to them as possible. More...
static int	calculatePointBetweenTwoLines_UsingVertex (const CLHEP::Hep3Vector &PA, const CLHEP::Hep3Vector &PB, const CLHEP::Hep3Vector &PC, const CLHEP::Hep3Vector &PD, const CLHEP::Hep3Vector &Vertex, CLHEP::Hep3Vector &point)
	Calculates the intersection of a line L and line PAPB ( strip on the first sensor ). More...

Protected Attributes
std::string	_TrackerHitCollection
	Input collection name.
std::string	_TrackerHitSimHitRelCollection
	Input relation collection name.
std::string	_SpacePointsCollection
	Output collection name.
std::string	_relColName
	Output relations collection name.
int	_nRun
int	_nEvt
unsigned	_nOutOfBoundary
unsigned	_nStripsTooParallel
unsigned	_nPlanesNotParallel
float	_nominal_vertex_x
float	_nominal_vertex_y
float	_nominal_vertex_z
CLHEP::Hep3Vector	_nominal_vertex
float	_striplength_tolerance
double	_striplength
std::string	_subDetName
const DD4hep::DDRec::SurfaceMap *	surfMap

Detailed Description

================= FTD Space Point Builder =================

Builds space points for pairs of silicon strip detectors. The digitisers create TrackerHitPlanars for the front and the back strips. In order to get a spacepoint (as is needed by track reconstruction) those strip measurements need to be combined into one space point.

This is done by this processor.

Input - Prerequisites

The TrackerHitPlanars as created by the Digitisers of FTD, SET or SIT. This could of course be used for other detectors as well, but as information about the detector is acquired from gear, and as different detectors (at the moment) are stored differently in gear, used detectors have to be taken care of in the code.

Output

A collection of TrackerHits containing the constructed space points. The created hits will store the original strip hits in their rawHits.

Parameters

TrackerHitCollection	The name of the input collection of TrackerHits coming from strip detectors on the FTD, SIT or SET (default name FTDTrackerHits)
SpacePointsCollection	The name of the output collection of the created spacepoints (default name FTDSpacePoints)
TrackerHitSimHitRelCollection	The name of the input collection of the relations of the TrackerHits to SimHits (default name FTDTrackerHitRelations)
SimHitSpacePointRelCollection	The name of the SpacePoint SimTrackerHit relation output collection (default name VTXTrackerHitRelations)

Author

Robin Glattauer HEPHY, Vienna

Member Function Documentation

int DDSpacePointBuilder::calculatePointBetweenTwoLines ( const CLHEP::Hep3Vector &  P1, const CLHEP::Hep3Vector &  V1, const CLHEP::Hep3Vector &  P2, const CLHEP::Hep3Vector &  V2, CLHEP::Hep3Vector &  point  )

staticprotected

Calculates a point between two lines in a way that it is equidistant from both lines and as close to them as possible.

So when you calculate the distance between two lines, and you actually draw this distance as a short connecting line, the point in the middle of this line, is what this method finds.

             /
            /
           /|___here!!!
          / |
---------/-------------- (line a)
        /
       /(line b)

(If this sketch looks terrible, you probably read this in doxygen and it still needs to be formatted in a way, that it still looks sensible in doxygen.)

Parameters

P1	a point on the first line
V1	the direction vector of the first line
point	the reference to a point where the result will be stored

References calculateXingPoint().

int DDSpacePointBuilder::calculatePointBetweenTwoLines_UsingVertex ( const CLHEP::Hep3Vector &  PA, const CLHEP::Hep3Vector &  PB, const CLHEP::Hep3Vector &  PC, const CLHEP::Hep3Vector &  PD, const CLHEP::Hep3Vector &  Vertex, CLHEP::Hep3Vector &  point  )

staticprotected

Calculates the intersection of a line L and line PAPB ( strip on the first sensor ).

L is constrained to pass through the point "Vertex" and bisect both lines PAPB ( strip on the first sensor ) and PCPD ( strip on the second sensor )

Parameters

PA	start of the first line
PB	end of the first line
PC	start of the second line
PD	end of the second line
Vertex	the position
point	the reference to a point where the result will be stored

Referenced by createSpacePoint().

int DDSpacePointBuilder::calculateXingPoint ( double  x1, double  y1, float  ex1, float  ey1, double  x2, double  y2, float  ex2, float  ey2, double &  x, double &  y  )

staticprotected

Calculates the 2 dimensional crossing point of two lines.

Each line is specified by a point (x,y) and a direction vector (ex,ey).

Returns

0, if the calculation has been successful, another number if there was a problem.

Referenced by calculatePointBetweenTwoLines().

TrackerHitImpl * DDSpacePointBuilder::createSpacePoint ( TrackerHitPlane *  a, TrackerHitPlane *  b, double  stripLength  )

protected

Returns

a spacepoint (in the form of a TrackerHitImpl* ) created from two TrackerHitPlane* which stand for si-strips

References calculatePointBetweenTwoLines_UsingVertex().

Referenced by processEvent().

std::string DDSpacePointBuilder::getCellID0Info ( int  cellID0 )

protected

Returns

information about the contents of the passed CellID0

Referenced by processEvent().

std::vector< int > DDSpacePointBuilder::getCellID0sAtBack ( int  cellID0 )

protected

Returns

the CellID0s of the sensors that are back to back to a given front sensor. If the given sensor is in the back itself or has no corresponding sensor(s) on the back the vector will be empty.

Parameters

cellID0

a CellID0 corresponding to a sensor

Referenced by processEvent().

void DDSpacePointBuilder::init ( )

virtual

Called at the begin of the job before anything is read.

Use to initialize the processor, e.g. book histograms.

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

• DDSpacePointBuilder.h
• DDSpacePointBuilder.cc