DedxDriftCell Class Reference

A class to hold the geometry of a cell. More...

#include <LineHelper.h>

Public Member Functions
	DedxDriftCell (const DedxLine &left, const DedxLine &top, const DedxLine &right, const DedxLine &bot)
	Construct a DedxDriftCell from four different DedxLines (sides)
	DedxDriftCell (const DedxPoint &tl, const DedxPoint &tr, const DedxPoint &br, const DedxPoint &bl)
	Construct a DedxDriftCell from four different DedxPoints (corners)
bool	isValid ()
	Check if this is a valid calculation (number of intersections = 2)
double	dx (const DedxPoint &poca, double entAng)
	Calculate the path length through this cell for a track with a given DedxPoint Of Closest Approach (poca) and entrance angle (entAng)
double	dx (double doca, double entAng)
	Calculate the path length through this cell for a track with a given Distance Of Closest Approach (doca) and entrance angle (entAng)

Private Attributes
DedxLine	m_Left
	the left boundary of the cell
DedxLine	m_Top
	the left boundary of the cell
DedxLine	m_Right
	the left boundary of the cell
DedxLine	m_Bot
	the left boundary of the cell
bool	m_isValid
	does the hit land in this cell

Detailed Description

A class to hold the geometry of a cell.

This class is used to actually calculate the path length of a track moving through a given cell.

Definition at line 186 of file LineHelper.h.

Constructor & Destructor Documentation

DedxDriftCell() [1/2]

DedxDriftCell ( const DedxLine &  left, const DedxLine &  top, const DedxLine &  right, const DedxLine &  bot  )

inline

Construct a DedxDriftCell from four different DedxLines (sides)

Definition at line 191 of file LineHelper.h.

                                                                                                         : m_Left(left), m_Top(top),
      m_Right(right), m_Bot(bot), m_isValid(true) {}

DedxDriftCell() [2/2]

DedxDriftCell ( const DedxPoint &  tl, const DedxPoint &  tr, const DedxPoint &  br, const DedxPoint &  bl  )

inline

Construct a DedxDriftCell from four different DedxPoints (corners)

Definition at line 195 of file LineHelper.h.

                                                                                                      :  m_Left(bl, tl), m_Top(tl, tr),
      m_Right(tr, br), m_Bot(br, bl), m_isValid(true) {}

Member Function Documentation

dx() [1/2]

double dx ( const DedxPoint &  poca, double  entAng  )

inline

Calculate the path length through this cell for a track with a given DedxPoint Of Closest Approach (poca) and entrance angle (entAng)

Definition at line 203 of file LineHelper.h.

    {
      // The path length (dx) is the length of the track in this cell.
      double Dx = 0;
 
      // The DedxPoint Of Closest Approach (poca) is useful for a reference point
      // to construct a line that represents the track.
      DedxLine track = DedxLine(poca, std::tan(M_PI_2 - entAng));
 
      // Find the points of intersection with each cell boundary
      DedxPoint intLeft = m_Left.intersection(track);
      DedxPoint intTop = m_Top.intersection(track);
      DedxPoint intRight = m_Right.intersection(track);
      DedxPoint intBot = m_Bot.intersection(track);
 
      std::vector<DedxPoint> endpoints;
      if (intLeft.isValid())
        endpoints.push_back(intLeft);
      if (intTop.isValid())
        endpoints.push_back(intTop);
      if (intRight.isValid())
        endpoints.push_back(intRight);
      if (intBot.isValid())
        endpoints.push_back(intBot);
 
      // Make sure we only get two intersections!
      if (endpoints.size() == 2) {
        Dx = endpoints[0].length(endpoints[1]);
        if (Dx == 0)
          m_isValid = false;
      } else
        m_isValid = false;
 
      return Dx;
    }

dx() [2/2]

double dx ( double  doca, double  entAng  )

inline

Calculate the path length through this cell for a track with a given Distance Of Closest Approach (doca) and entrance angle (entAng)

Definition at line 241 of file LineHelper.h.

    {
      // The path length (dx) is the length of the track in this cell.
      double Dx = 0;
 
      // The DedxPoint Of Closest Approach (poca) is useful for a reference point
      // to construct a line that represents the track.
      const DedxPoint poca = DedxPoint(doca * std::abs(std::cos(entAng)), -1.0 * doca * std::sin(entAng));
      DedxLine track = DedxLine(poca, std::tan(M_PI_2 - entAng));
 
      // Find the points of intersection with each cell boundary
      DedxPoint intLeft = m_Left.intersection(track);
      DedxPoint intTop = m_Top.intersection(track);
      DedxPoint intRight = m_Right.intersection(track);
      DedxPoint intBot = m_Bot.intersection(track);
 
      std::vector< DedxPoint > endpoints;
      if (intLeft.isValid())
        endpoints.push_back(intLeft);
      if (intTop.isValid())
        endpoints.push_back(intTop);
      if (intRight.isValid())
        endpoints.push_back(intRight);
      if (intBot.isValid())
        endpoints.push_back(intBot);
 
      // Make sure we only get two intersections!
      if (endpoints.size() == 2) {
        Dx = endpoints[0].length(endpoints[1]);
        if (Dx == 0)
          m_isValid = false;
      } else
        m_isValid = false;
 
      return Dx;
    }

isValid()

bool isValid ( )

inline

Check if this is a valid calculation (number of intersections = 2)

Definition at line 199 of file LineHelper.h.

{ return m_isValid; }

Member Data Documentation

m_Bot

DedxLine m_Bot

private

the left boundary of the cell

Definition at line 283 of file LineHelper.h.

m_isValid

bool m_isValid

private

does the hit land in this cell

Definition at line 284 of file LineHelper.h.

m_Left

DedxLine m_Left

private

the left boundary of the cell

Definition at line 280 of file LineHelper.h.

m_Right

DedxLine m_Right

private

the left boundary of the cell

Definition at line 282 of file LineHelper.h.

m_Top

DedxLine m_Top

private

the left boundary of the cell

Definition at line 281 of file LineHelper.h.

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

• reconstruction/modules/CDCDedxPID/include/LineHelper.h