#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 GlobalTrajectoryParameters &sta, const GlobalTrajectoryParameters &stb)
virtual bool	calculate (const FreeTrajectoryState &sta, const FreeTrajectoryState &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)
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 63 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 m, status_, and theModus.

Referenced by clone().

{ theModus=m; status_ = false;};

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(), CrossingPtBasedLinearizationPointFinder::getLinearizationPoint(), InclusiveVertexFinder::nearTracks(), TSCBLBuilderNoMaterial::operator()(), and CrossingPtBasedLinearizationPointFinder::useAllTracks().

{
  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(), GlobalTrajectoryParameters::position(), and z.

{
  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 [inline, virtual]

Clone method

Implements ClosestApproachOnHelices.

Definition at line 54 of file TwoTrackMinimumDistance.h.

References TwoTrackMinimumDistance().

                                                  {
    return new TwoTrackMinimumDistance(* this);
  }

GlobalPoint TwoTrackMinimumDistance::crossingPoint ( ) const [virtual]

arithmetic mean of the two points of closest approach

Implements ClosestApproachOnHelices.

Definition at line 183 of file TwoTrackMinimumDistance.cc.

References timingPdfMaker::mean.

Referenced by VZeroFinder::checkTrackPair(), and InclusiveVertexFinder::nearTracks().

{
  return mean ( points_ );
}

float TwoTrackMinimumDistance::distance ( ) const [virtual]

distance between the two points of closest approach in 3D

Implements ClosestApproachOnHelices.

Definition at line 189 of file TwoTrackMinimumDistance.cc.

Referenced by VZeroFinder::checkTrackPair(), and InclusiveVertexFinder::nearTracks().

{
  return dist ( points_ );
}

double TwoTrackMinimumDistance::firstAngle ( ) const

Definition at line 20 of file TwoTrackMinimumDistance.cc.

References Exception.

Referenced by VZeroFinder::checkTrackPair(), 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.

Referenced by 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 CrossingPtBasedLinearizationPointFinder::getLinearizationPoint(), InclusiveVertexFinder::nearTracks(), TSCBLBuilderNoMaterial::operator()(), 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(), alignCSCRings::e, f, mag2(), GlobalTrajectoryParameters::momentum(), GlobalTrajectoryParameters::position(), and z.

{
  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 {
    points_ = theTTMDhh.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.

{
  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.

{
  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.

Referenced by VZeroFinder::checkTrackPair().

{
  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;
}