TwoTrackMinimumDistanceHelixHelix Class Reference

#include <TwoTrackMinimumDistanceHelixHelix.h>

Public Member Functions
bool	calculate (const GlobalTrajectoryParameters &, const GlobalTrajectoryParameters &, const float qual=.001)
double	firstAngle () const
std::pair< double, double >	pathLength () const
std::pair< GlobalPoint, GlobalPoint >	points () const
double	secondAngle () const
	TwoTrackMinimumDistanceHelixHelix ()
	~TwoTrackMinimumDistanceHelixHelix ()

Private Member Functions
void	finalPoints ()
bool	oneIteration (double &, double &)
bool	updateCoeffs (const GlobalPoint &, const GlobalPoint &)

Private Attributes
double	pathG
double	pathH
GlobalPoint	pointG
GlobalPoint	pointH
bool	pointsUpdated
double	thea
double	theb
double	thec1
double	thec2
double	thecospG
double	thecospG0
double	thecospH
double	thecospH0
double	thed1
double	thed2
double	thee1
double	thee2
GlobalTrajectoryParameters const *	theG
double	theg
GlobalTrajectoryParameters const *	theH
double	theh
int	themaxiter
double	themaxjump
double	thepG
double	thepG0
double	thepH
double	thepH0
double	thesingjacI
double	thesinpG
double	thesinpG0
double	thesinpH
double	thesinpH0
double	thetanlambdaG
double	thetanlambdaH

Detailed Description

This is a helper class for TwoTrackMinimumDistance. No user should need direct access to this class. It actually implements a Newton-Kantorowitsch method for finding the minimum distance between two tracks.

Definition at line 18 of file TwoTrackMinimumDistanceHelixHelix.h.

Constructor & Destructor Documentation

TwoTrackMinimumDistanceHelixHelix::TwoTrackMinimumDistanceHelixHelix

(

)

Definition at line 10 of file TwoTrackMinimumDistanceHelixHelix.cc.

    : theH(nullptr), theG(nullptr), pointsUpdated(false), themaxjump(20), thesingjacI(1. / 0.1), themaxiter(4) {}

TwoTrackMinimumDistanceHelixHelix::~TwoTrackMinimumDistanceHelixHelix

(

)

Definition at line 13 of file TwoTrackMinimumDistanceHelixHelix.cc.

{}

Member Function Documentation

bool TwoTrackMinimumDistanceHelixHelix::calculate	(	const GlobalTrajectoryParameters &	G,
		const GlobalTrajectoryParameters &	H,
		const float	qual = .001
	)

Definition at line 112 of file TwoTrackMinimumDistanceHelixHelix.cc.

References finalPoints(), callgraph::G, class-composition::H, edm::isNotFinite(), oneIteration(), pointsUpdated, GlobalTrajectoryParameters::position(), theG, theg, theH, theh, themaxiter, themaxjump, thepG, thepG0, thepH, thepH0, and updateCoeffs().

                                                                    {
  pointsUpdated = false;
  theG = &G;
  theH = &H;
  bool retval = false;

  if (updateCoeffs(theG->position(), theH->position())) {
    finalPoints();
    return true;
  }

  thepG = thepG0;
  thepH = thepH0;

  int counter = 0;
  double pH = 0;
  double pG = 0;
  do {
    retval = oneIteration(pG, pH);
    if (edm::isNotFinite(pG) || edm::isNotFinite(pH))
      retval = true;
    if (counter++ > themaxiter)
      retval = true;
  } while ((!retval) && (fabs(pG) > qual || fabs(pH) > qual));
  if (fabs(theg * (thepG - thepG0)) > themaxjump)
    retval = true;
  if (fabs(theh * (thepH - thepH0)) > themaxjump)
    retval = true;

  finalPoints();

  return retval;
}

void TwoTrackMinimumDistanceHelixHelix::finalPoints ( )

private

Definition at line 148 of file TwoTrackMinimumDistanceHelixHelix.cc.

References funct::cos(), pathG, pathH, pointG, pointH, pointsUpdated, GlobalTrajectoryParameters::position(), funct::sin(), mathSSE::sqrt(), thecospG0, thecospH0, theG, theg, theH, theh, thepG, thepG0, thepH, thepH0, thesinpG0, thesinpH0, thetanlambdaG, and thetanlambdaH.

Referenced by calculate(), and secondAngle().

                                                    {
  if (pointsUpdated)
    return;
  GlobalVector tmpG(sin(thepG) - thesinpG0, -cos(thepG) + thecospG0, thetanlambdaG * (thepG - thepG0));
  pointG = theG->position() + theg * tmpG;
  pathG = (thepG - thepG0) * (theg * sqrt(1 + thetanlambdaG * thetanlambdaG));

  GlobalVector tmpH(sin(thepH) - thesinpH0, -cos(thepH) + thecospH0, thetanlambdaH * (thepH - thepH0));
  pointH = theH->position() + theh * tmpH;
  pathH = (thepH - thepH0) * (theh * sqrt(1 + thetanlambdaH * thetanlambdaH));

  pointsUpdated = true;
}

double TwoTrackMinimumDistanceHelixHelix::firstAngle ( ) const

inline

Definition at line 31 of file TwoTrackMinimumDistanceHelixHelix.h.

References thepG.

{ return thepG; }

bool TwoTrackMinimumDistanceHelixHelix::oneIteration ( double &  dH, double &  dG  )

private

Definition at line 69 of file TwoTrackMinimumDistanceHelixHelix.cc.

References funct::cos(), funct::sin(), thea, theb, thec1, thec2, thecospG, thecospH, thed1, thed2, thee1, thee2, theg, theh, thepG, thepH, thesingjacI, thesinpG, thesinpH, and testProducerWithPsetDescEmpty_cfi::z2.

Referenced by calculate(), and secondAngle().

                                                                           {
  thesinpH = sin(thepH);
  thecospH = cos(thepH);
  thesinpG = sin(thepG);
  thecospG = cos(thepG);

  const double A11 = theh * (-thesinpH * (thea - theg * thesinpG) + thecospH * (theb + theg * thecospG) + thec1);
  if (A11 < 0) {
    return true;
  };
  const double A22 = -theg * (-thesinpG * (thea + theh * thesinpH) + thecospG * (theb - theh * thecospH) + thec2);
  if (A22 < 0) {
    return true;
  };
  const double A12 = theh * (-theg * thecospG * thecospH - theg * thesinpH * thesinpG + thed1);
  const double A21 = -theg * (theh * thecospG * thecospH + theh * thesinpH * thesinpG + thed2);
  const double detaI = 1. / (A11 * A22 - A12 * A21);
  const double z1 = theh * (thecospH * (thea - theg * thesinpG) + thesinpH * (theb + theg * thecospG) + thec1 * thepH +
                            thed1 * thepG + thee1);
  const double z2 = -theg * (thecospG * (thea + theh * thesinpH) + thesinpG * (theb - theh * thecospH) + thec2 * thepG +
                             thed2 * thepH + thee2);

  dH = (z1 * A22 - z2 * A12) * detaI;
  dG = (z2 * A11 - z1 * A21) * detaI;
  if (fabs(detaI) > thesingjacI) {
    return true;
  };

  thepH -= dH;
  thepG -= dG;
  return false;
}

std::pair<double, double> TwoTrackMinimumDistanceHelixHelix::pathLength ( ) const

inline

Definition at line 29 of file TwoTrackMinimumDistanceHelixHelix.h.

References pathG, and pathH.

{ return std::pair<double, double>(pathG, pathH); }

std::pair<GlobalPoint, GlobalPoint> TwoTrackMinimumDistanceHelixHelix::points ( ) const

inline

Definition at line 27 of file TwoTrackMinimumDistanceHelixHelix.h.

References pointG, and pointH.

{ return std::pair<GlobalPoint, GlobalPoint>(pointG, pointH); }

double TwoTrackMinimumDistanceHelixHelix::secondAngle ( ) const

inline

Definition at line 32 of file TwoTrackMinimumDistanceHelixHelix.h.

References finalPoints(), oneIteration(), thepH, and updateCoeffs().

{ return thepH; }

bool TwoTrackMinimumDistanceHelixHelix::updateCoeffs ( const GlobalPoint &  gpH, const GlobalPoint &  gpG  )

private

Definition at line 15 of file TwoTrackMinimumDistanceHelixHelix.cc.

References GlobalTrajectoryParameters::charge(), MagneticField::inInverseGeV(), GlobalTrajectoryParameters::magneticField(), GlobalTrajectoryParameters::momentum(), PV3DBase< T, PVType, FrameType >::perp(), GlobalTrajectoryParameters::position(), thea, theb, thec1, thec2, thecospG0, thecospH0, thed1, thed2, thee1, thee2, theG, theg, theH, theh, thepG0, thepH0, thesinpG0, thesinpH0, thetanlambdaG, thetanlambdaH, PV3DBase< T, PVType, FrameType >::x(), PV3DBase< T, PVType, FrameType >::y(), and PV3DBase< T, PVType, FrameType >::z().

Referenced by calculate(), and secondAngle().

                                                                                                   {
  const double Bc2kH = theH->magneticField().inInverseGeV(gpH).z();
  const double Bc2kG = theG->magneticField().inInverseGeV(gpG).z();
  const double Ht = theH->momentum().perp();
  const double Gt = theG->momentum().perp();
  //  thelambdaH=asin ( theH->momentum().z() / Hn );

  if (Ht == 0. || Gt == 0.) {
    edm::LogWarning("TwoTrackMinimumDistanceHelixHelix") << "transverse momentum of input trajectory is zero.";
    return true;
  };

  if (theH->charge() == 0. || theG->charge() == 0.) {
    edm::LogWarning("TwoTrackMinimumDistanceHelixHelix") << "charge of input track is zero.";
    return true;
  };

  if (Bc2kG == 0.) {
    edm::LogWarning("TwoTrackMinimumDistanceHelixHelix") << "magnetic field at point " << gpG << " is zero.";
    return true;
  };

  if (Bc2kH == 0.) {
    edm::LogWarning("TwoTrackMinimumDistanceHelixHelix") << "magnetic field at point " << gpH << " is zero.";
    return true;
  };

  theh = Ht / (theH->charge() * Bc2kH);
  thesinpH0 = -theH->momentum().y() / (Ht);
  thecospH0 = -theH->momentum().x() / (Ht);
  thetanlambdaH = -theH->momentum().z() / (Ht);
  thepH0 = atan2(thesinpH0, thecospH0);

  // thelambdaG=asin ( theG->momentum().z()/( Gn ) );

  theg = Gt / (theG->charge() * Bc2kG);
  thesinpG0 = -theG->momentum().y() / (Gt);
  thecospG0 = -theG->momentum().x() / (Gt);
  thetanlambdaG = -theG->momentum().z() / (Gt);
  thepG0 = atan2(thesinpG0, thecospG0);

  thea = theH->position().x() - theG->position().x() + theg * thesinpG0 - theh * thesinpH0;
  theb = theH->position().y() - theG->position().y() - theg * thecospG0 + theh * thecospH0;
  thec1 = theh * thetanlambdaH * thetanlambdaH;
  thec2 = -theg * thetanlambdaG * thetanlambdaG;
  thed1 = -theg * thetanlambdaG * thetanlambdaH;
  thed2 = theh * thetanlambdaG * thetanlambdaH;
  thee1 = thetanlambdaH *
          (theH->position().z() - theG->position().z() - theh * thepH0 * thetanlambdaH + theg * thepG0 * thetanlambdaG);
  thee2 = thetanlambdaG *
          (theH->position().z() - theG->position().z() - theh * thepH0 * thetanlambdaH + theg * thepG0 * thetanlambdaG);
  return false;
}

Member Data Documentation

double TwoTrackMinimumDistanceHelixHelix::pathG

private

Definition at line 57 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by finalPoints(), and pathLength().

double TwoTrackMinimumDistanceHelixHelix::pathH

private

Definition at line 57 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by finalPoints(), and pathLength().

GlobalPoint TwoTrackMinimumDistanceHelixHelix::pointG

private

Definition at line 56 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by finalPoints(), and points().

GlobalPoint TwoTrackMinimumDistanceHelixHelix::pointH

private

Definition at line 56 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by finalPoints(), and points().

bool TwoTrackMinimumDistanceHelixHelix::pointsUpdated

private

Definition at line 58 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by calculate(), and finalPoints().

double TwoTrackMinimumDistanceHelixHelix::thea

private

Definition at line 44 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by oneIteration(), and updateCoeffs().

double TwoTrackMinimumDistanceHelixHelix::theb

private

Definition at line 44 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by oneIteration(), and updateCoeffs().

double TwoTrackMinimumDistanceHelixHelix::thec1

private

Definition at line 44 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by oneIteration(), and updateCoeffs().

double TwoTrackMinimumDistanceHelixHelix::thec2

private

Definition at line 44 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by oneIteration(), and updateCoeffs().

double TwoTrackMinimumDistanceHelixHelix::thecospG

private

Definition at line 55 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by oneIteration().

double TwoTrackMinimumDistanceHelixHelix::thecospG0

private

Definition at line 47 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by finalPoints(), and updateCoeffs().

double TwoTrackMinimumDistanceHelixHelix::thecospH

private

Definition at line 55 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by oneIteration().

double TwoTrackMinimumDistanceHelixHelix::thecospH0

private

Definition at line 48 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by finalPoints(), and updateCoeffs().

double TwoTrackMinimumDistanceHelixHelix::thed1

private

Definition at line 44 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by oneIteration(), and updateCoeffs().

double TwoTrackMinimumDistanceHelixHelix::thed2

private

Definition at line 44 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by oneIteration(), and updateCoeffs().

double TwoTrackMinimumDistanceHelixHelix::thee1

private

Definition at line 44 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by oneIteration(), and updateCoeffs().

double TwoTrackMinimumDistanceHelixHelix::thee2

private

Definition at line 44 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by oneIteration(), and updateCoeffs().

GlobalTrajectoryParameters const * TwoTrackMinimumDistanceHelixHelix::theG

private

Definition at line 42 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by calculate(), finalPoints(), and updateCoeffs().

double TwoTrackMinimumDistanceHelixHelix::theg

private

Definition at line 44 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by calculate(), finalPoints(), oneIteration(), and updateCoeffs().

GlobalTrajectoryParameters const* TwoTrackMinimumDistanceHelixHelix::theH

private

Definition at line 42 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by calculate(), finalPoints(), and updateCoeffs().

double TwoTrackMinimumDistanceHelixHelix::theh

private

Definition at line 44 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by calculate(), finalPoints(), oneIteration(), and updateCoeffs().

int TwoTrackMinimumDistanceHelixHelix::themaxiter

private

Definition at line 61 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by calculate().

double TwoTrackMinimumDistanceHelixHelix::themaxjump

private

Definition at line 60 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by calculate().

double TwoTrackMinimumDistanceHelixHelix::thepG

private

Definition at line 53 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by calculate(), finalPoints(), firstAngle(), and oneIteration().

double TwoTrackMinimumDistanceHelixHelix::thepG0

private

Definition at line 49 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by calculate(), finalPoints(), and updateCoeffs().

double TwoTrackMinimumDistanceHelixHelix::thepH

private

Definition at line 53 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by calculate(), finalPoints(), oneIteration(), and secondAngle().

double TwoTrackMinimumDistanceHelixHelix::thepH0

private

Definition at line 49 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by calculate(), finalPoints(), and updateCoeffs().

double TwoTrackMinimumDistanceHelixHelix::thesingjacI

private

Definition at line 60 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by oneIteration().

double TwoTrackMinimumDistanceHelixHelix::thesinpG

private

Definition at line 54 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by oneIteration().

double TwoTrackMinimumDistanceHelixHelix::thesinpG0

private

Definition at line 47 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by finalPoints(), and updateCoeffs().

double TwoTrackMinimumDistanceHelixHelix::thesinpH

private

Definition at line 54 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by oneIteration().

double TwoTrackMinimumDistanceHelixHelix::thesinpH0

private

Definition at line 48 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by finalPoints(), and updateCoeffs().

double TwoTrackMinimumDistanceHelixHelix::thetanlambdaG

private

Definition at line 46 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by finalPoints(), and updateCoeffs().

double TwoTrackMinimumDistanceHelixHelix::thetanlambdaH

private

Definition at line 46 of file TwoTrackMinimumDistanceHelixHelix.h.

Referenced by finalPoints(), and updateCoeffs().