TwoTrackMinimumDistance Class Reference

#include <TwoTrackMinimumDistance.h>

Inheritance diagram for TwoTrackMinimumDistance:

Public Types
enum	Mode { FastMode =0, SlowMode =1 }

Public Member Functions
virtual bool	calculate (const TrajectoryStateOnSurface &sta, const TrajectoryStateOnSurface &stb)
virtual bool	calculate (const FreeTrajectoryState &sta, const FreeTrajectoryState &stb)
virtual bool	calculate (const GlobalTrajectoryParameters &sta, const GlobalTrajectoryParameters &stb)
virtual TwoTrackMinimumDistance *	clone () const
virtual GlobalPoint	crossingPoint () const
virtual float	distance () const
double	firstAngle () const
std::pair< double, double >	pathLength () const
virtual std::pair< GlobalPoint, GlobalPoint >	points () const
double	secondAngle () const
virtual bool	status () const
	TwoTrackMinimumDistance (const Mode m=FastMode)
	~TwoTrackMinimumDistance ()
Public Member Functions inherited from ClosestApproachOnHelices
	ClosestApproachOnHelices ()
virtual	~ClosestApproachOnHelices ()

Private Types
enum	Charge { hh, hl, ll }

Private Member Functions
bool	pointsHelixHelix (const GlobalTrajectoryParameters &sta, const GlobalTrajectoryParameters &stb)
bool	pointsHelixLine (const GlobalTrajectoryParameters &sta, const GlobalTrajectoryParameters &stb)
bool	pointsLineLine (const GlobalTrajectoryParameters &sta, const GlobalTrajectoryParameters &stb)

Private Attributes
std::pair< GlobalPoint, GlobalPoint >	points_
bool	status_
Charge	theCharge
ClosestApproachInRPhi	theIniAlgo
Mode	theModus
TwoTrackMinimumDistanceHelixHelix	theTTMDhh
TwoTrackMinimumDistanceHelixLine	theTTMDhl
TwoTrackMinimumDistanceLineLine	theTTMDll

Detailed Description

General interface to calculate the PCA of two tracks. According to the charge of the tracks, the correct algorithm is used:

• charged-charged: TwoTrackMinimumDistanceHelixHelix
• charged-neutral: TwoTrackMinimumDistanceHelixLine
• neutral-neutral: TwoTrackMinimumDistanceLineLine

Definition at line 19 of file TwoTrackMinimumDistance.h.

Member Enumeration Documentation

enum TwoTrackMinimumDistance::Charge

private

Enumerator
hh
hl
ll

Definition at line 64 of file TwoTrackMinimumDistance.h.

{ hh, hl, ll };

enum TwoTrackMinimumDistance::Mode

Enumerator
FastMode
SlowMode

Definition at line 23 of file TwoTrackMinimumDistance.h.

{ FastMode=0, SlowMode=1 };

Constructor & Destructor Documentation

TwoTrackMinimumDistance::TwoTrackMinimumDistance ( const Mode  m = FastMode )

inline

Definition at line 25 of file TwoTrackMinimumDistance.h.

References funct::m, status_, and theModus.

Referenced by clone().

{ theModus=m; status_ = false;};

TwoTrackMinimumDistance::~TwoTrackMinimumDistance ( )

inline

Definition at line 26 of file TwoTrackMinimumDistance.h.

References calculate().

{}

Member Function Documentation

bool TwoTrackMinimumDistance::calculate ( const TrajectoryStateOnSurface &  sta, const TrajectoryStateOnSurface &  stb  )

virtual

Implements ClosestApproachOnHelices.

Definition at line 65 of file TwoTrackMinimumDistance.cc.

References TrajectoryStateOnSurface::globalParameters().

Referenced by VZeroFinder::checkTrackPair(), BPHWriteSpecificDecay::fill(), CrossingPtBasedLinearizationPointFinder::getLinearizationPoint(), PFDisplacedVertexCandidateFinder::link(), TracksClusteringFromDisplacedSeed::nearTracks(), TSCBLBuilderNoMaterial::operator()(), Onia2MuMuPAT::produce(), CrossingPtBasedLinearizationPointFinder::useAllTracks(), and ~TwoTrackMinimumDistance().

{
  return calculate ( sta.globalParameters(), stb.globalParameters() );
}

bool TwoTrackMinimumDistance::calculate ( const FreeTrajectoryState &  sta, const FreeTrajectoryState &  stb  )

virtual

Implements ClosestApproachOnHelices.

Definition at line 73 of file TwoTrackMinimumDistance.cc.

References FreeTrajectoryState::parameters().

{
//  pair<GlobalPoint, GlobalPoint> ret  = theIniAlgo.points ( sta, stb );
  return calculate ( sta.parameters(), stb.parameters() );
}

bool TwoTrackMinimumDistance::calculate ( const GlobalTrajectoryParameters &  sta, const GlobalTrajectoryParameters &  stb  )

virtual

Definition at line 81 of file TwoTrackMinimumDistance.cc.

References GlobalTrajectoryParameters::charge(), MagneticField::inTesla(), GlobalTrajectoryParameters::magneticField(), and GlobalTrajectoryParameters::position().

{
  bool isHelixA = (sta.magneticField().inTesla(sta.position()).z() != 0.)
    && sta.charge() != 0.;
  bool isHelixB = (stb.magneticField().inTesla(stb.position()).z() != 0.)
    && stb.charge() != 0.;
  if (! isHelixA && ! isHelixB) {
    status_ = pointsLineLine(sta, stb);
  } else if ( isHelixA && isHelixB ) {
    status_ = pointsHelixHelix(sta, stb);
  } else {
    status_ = pointsHelixLine(sta, stb);
  }
  return status_;
}

virtual TwoTrackMinimumDistance* TwoTrackMinimumDistance::clone ( void  ) const

inlinevirtual

Clone method

Implements ClosestApproachOnHelices.

Definition at line 55 of file TwoTrackMinimumDistance.h.

References firstAngle(), pathLength(), secondAngle(), and TwoTrackMinimumDistance().

                                                  {
    return new TwoTrackMinimumDistance(* this);
  }

GlobalPoint TwoTrackMinimumDistance::crossingPoint ( ) const

virtual

arithmetic mean of the two points of closest approach

Implements ClosestApproachOnHelices.

Definition at line 185 of file TwoTrackMinimumDistance.cc.

References RecoTauDiscriminantConfiguration::mean.

Referenced by VZeroFinder::checkTrackPair(), PFDisplacedVertexCandidateFinder::link(), TracksClusteringFromDisplacedSeed::nearTracks(), and status().

{
  return mean ( points_ );
}

float TwoTrackMinimumDistance::distance ( ) const

virtual

distance between the two points of closest approach in 3D

Implements ClosestApproachOnHelices.

Definition at line 191 of file TwoTrackMinimumDistance.cc.

Referenced by VZeroFinder::checkTrackPair(), PFDisplacedVertexCandidateFinder::link(), TracksClusteringFromDisplacedSeed::nearTracks(), and status().

{
  return dist ( points_ );
}

double TwoTrackMinimumDistance::firstAngle

(

)

const

Definition at line 20 of file TwoTrackMinimumDistance.cc.

References Exception, and AlignmentTrackSelector_cfi::theCharge.

Referenced by VZeroFinder::checkTrackPair(), clone(), and TSCBLBuilderNoMaterial::operator()().

{
  if (!status_)
    throw cms::Exception("TrackingTools/PatternTools","TwoTrackMinimumDistance::could not compute track crossing. Check status before calling this method!");
  switch ( theCharge ) {
   case (hh): return theTTMDhh.firstAngle(); break;
   case (hl): return theTTMDhl.firstAngle(); break;
   case (ll): return theTTMDll.firstAngle(); break;
  }
  return 0;
}

pair< double, double > TwoTrackMinimumDistance::pathLength

(

)

const

Definition at line 45 of file TwoTrackMinimumDistance.cc.

References Exception, and AlignmentTrackSelector_cfi::theCharge.

Referenced by clone(), and TSCBLBuilderNoMaterial::operator()().

{
  if (!status_)
    throw cms::Exception("TrackingTools/PatternTools","TwoTrackMinimumDistance::could not compute track crossing. Check status before calling this method!");
  switch ( theCharge ) {
   case (hh): return theTTMDhh.pathLength(); break;
   case (hl): return theTTMDhl.pathLength(); break;
   case (ll): return theTTMDll.pathLength(); break;
  }
  return std::pair<double,double>(0,0);
}

pair< GlobalPoint, GlobalPoint > TwoTrackMinimumDistance::points ( ) const

virtual

Returns the two PCA on the trajectories.

Implements ClosestApproachOnHelices.

Definition at line 57 of file TwoTrackMinimumDistance.cc.

References Exception.

Referenced by BPHWriteSpecificDecay::fill(), CrossingPtBasedLinearizationPointFinder::getLinearizationPoint(), TracksClusteringFromDisplacedSeed::nearTracks(), TSCBLBuilderNoMaterial::operator()(), Onia2MuMuPAT::produce(), status(), and CrossingPtBasedLinearizationPointFinder::useAllTracks().

{
  if (!status_)
    throw cms::Exception("TrackingTools/PatternTools","TwoTrackMinimumDistance::could not compute track crossing. Check status before calling this method!");
  return points_;
}

bool TwoTrackMinimumDistance::pointsHelixHelix ( const GlobalTrajectoryParameters &  sta, const GlobalTrajectoryParameters &  stb  )

private

Definition at line 119 of file TwoTrackMinimumDistance.cc.

References GlobalTrajectoryParameters::charge(), MillePedeFileConverter_cfg::e, f, mag2(), GlobalTrajectoryParameters::momentum(), GlobalTrajectoryParameters::position(), and AlignmentTrackSelector_cfi::theCharge.

{
  if ( ( sta.position() - stb.position() ).mag2() < 1e-7f &&
       ( sta.momentum() - stb.momentum() ).mag2() < 1e-7f &&
       sta.charge()==stb.charge()
       )
  {
    edm::LogWarning ( "TwoTrackMinimumDistance") << "comparing track with itself!";
  };

  theCharge = hh;
  if ( theModus == FastMode )
  {
    // first we try directly - in FastMode only ...
    if ( !(theTTMDhh.calculate ( sta, stb, .0001 )) )
    {
      points_ = theTTMDhh.points();
      return true;
    };
  };

  // okay. did not work. so we use CAIR, and then TTMD again.
  bool cairStat = theIniAlgo.calculate ( sta, stb );
  
  if (!cairStat) { // yes. CAIR may fail.
    edm::LogWarning ( "TwoTrackMinimumDistance" ) << "Computation HelixHelix::CAIR failed.";
    if ( theModus == SlowMode ) { // we can still try ttmd here.
      if ( !(theTTMDhh.calculate ( sta, stb, .0001 )) ) {
    points_ = theTTMDhh.points();
        return true;
      }
    };
    // we can try with more sloppy settings
    if ( !(theTTMDhh.calculate ( sta, stb, .1 )) ) {
    points_ = theTTMDhh.points();
        return true;
      }
    return false;
    edm::LogWarning ( "TwoTrackMinimumDistance" ) << "TwoTrackMinimumDistanceHelixHelix failed";
  };

  pair<GlobalTrajectoryParameters, GlobalTrajectoryParameters >
    ini = theIniAlgo.trajectoryParameters();

  pair<GlobalPoint, GlobalPoint> inip ( ini.first.position(), 
      ini.second.position() );
  bool isFirstALine = ini.first.charge() == 0. || ini.first.magneticField().inTesla(ini.first.position()).z() == 0.;
  bool isSecondALine = ini.second.charge() == 0. || ini.second.magneticField().inTesla(ini.second.position()).z() == 0.;
  bool gotDist = false;
  if (!isFirstALine && !isSecondALine) gotDist = theTTMDhh.calculate ( ini.first, ini.second, .0001 );
  else if ( isFirstALine && isSecondALine) gotDist = theTTMDll.calculate ( ini.first, ini.second );
  else gotDist = theTTMDhl.calculate ( ini.first, ini.second, .0001 );
  if ( gotDist ) {
    points_ = inip;
  } else {
    if (!isFirstALine && !isSecondALine) points_ = theTTMDhh.points ();
    else if ( isFirstALine && isSecondALine) points_ = theTTMDll.points ();
    else points_ = theTTMDhl.points ();
    // if we are still worse than CAIR, we use CAIR results.
    if ( dist ( points_ ) > dist ( inip ) ) points_ = inip;
  };
  return true;
}

bool TwoTrackMinimumDistance::pointsHelixLine ( const GlobalTrajectoryParameters &  sta, const GlobalTrajectoryParameters &  stb  )

private

Definition at line 109 of file TwoTrackMinimumDistance.cc.

References AlignmentTrackSelector_cfi::theCharge.

{
  theCharge = hl;
  if (theTTMDhl.calculate(sta, stb, 0.000001)) return false;
  points_ = theTTMDhl.points();
  return true;
}

bool TwoTrackMinimumDistance::pointsLineLine ( const GlobalTrajectoryParameters &  sta, const GlobalTrajectoryParameters &  stb  )

private

Definition at line 99 of file TwoTrackMinimumDistance.cc.

References AlignmentTrackSelector_cfi::theCharge.

{
  theCharge = ll;
  if (theTTMDll.calculate(sta, stb)) return false;
  points_ = theTTMDll.points();
  return true;
}

double TwoTrackMinimumDistance::secondAngle

(

)

const

Definition at line 32 of file TwoTrackMinimumDistance.cc.

References Exception, and AlignmentTrackSelector_cfi::theCharge.

Referenced by VZeroFinder::checkTrackPair(), and clone().

{
  if (!status_)
    throw cms::Exception("TrackingTools/PatternTools","TwoTrackMinimumDistance::could not compute track crossing. Check status before calling this method!");
  switch ( theCharge ) {
   case (hh): return theTTMDhh.secondAngle(); break;
   case (hl): return theTTMDhl.secondAngle(); break;
   case (ll): return theTTMDll.secondAngle(); break;
  }
  return 0;
}

virtual bool TwoTrackMinimumDistance::status ( void  ) const

inlinevirtual

Implements ClosestApproachOnHelices.

Definition at line 37 of file TwoTrackMinimumDistance.h.

References crossingPoint(), distance(), points(), and status_.

{return status_;}

Member Data Documentation

std::pair<GlobalPoint, GlobalPoint> TwoTrackMinimumDistance::points_

private

Definition at line 72 of file TwoTrackMinimumDistance.h.

bool TwoTrackMinimumDistance::status_

private

Definition at line 71 of file TwoTrackMinimumDistance.h.

Referenced by status(), and TwoTrackMinimumDistance().

Charge TwoTrackMinimumDistance::theCharge

mutableprivate

Definition at line 66 of file TwoTrackMinimumDistance.h.

ClosestApproachInRPhi TwoTrackMinimumDistance::theIniAlgo

private

Definition at line 67 of file TwoTrackMinimumDistance.h.

Mode TwoTrackMinimumDistance::theModus

private

Definition at line 65 of file TwoTrackMinimumDistance.h.

Referenced by TwoTrackMinimumDistance().

TwoTrackMinimumDistanceHelixHelix TwoTrackMinimumDistance::theTTMDhh

mutableprivate

Definition at line 68 of file TwoTrackMinimumDistance.h.

TwoTrackMinimumDistanceHelixLine TwoTrackMinimumDistance::theTTMDhl

mutableprivate

Definition at line 70 of file TwoTrackMinimumDistance.h.

TwoTrackMinimumDistanceLineLine TwoTrackMinimumDistance::theTTMDll

mutableprivate

Definition at line 69 of file TwoTrackMinimumDistance.h.