#include <HelixForwardPlaneCrossing.h>

Inheritance diagram for HelixForwardPlaneCrossing:

Public Member Functions
DirectionType	direction (double s) const override

	HelixForwardPlaneCrossing (const PositionType &point, const DirectionType &direction, const float curvature, const PropagationDirection propDir=alongMomentum)

std::pair< bool, double >	pathLength (const Plane &plane) override

PositionType	position (double s) const override

	~HelixForwardPlaneCrossing () override

Public Member Functions inherited from HelixPlaneCrossing
virtual	~HelixPlaneCrossing ()=default

Private Types
typedef Basic3DVector< double >	DirectionTypeDouble

typedef Basic3DVector< double >	PositionTypeDouble

Private Attributes
double	theCachedCDPhi

double	theCachedDPhi

double	theCachedS

double	theCachedSDPhi

double	theCosPhi0

double	theCosTheta

const PropagationDirection	thePropDir

const double	theRho

double	theSinPhi0

double	theSinTheta

const double	theX0

const double	theY0

const double	theZ0

Static Private Attributes
static const float	theNumericalPrecision = 5.e-7

Additional Inherited Members
Public Types inherited from HelixPlaneCrossing
typedef Basic3DVector< float >	DirectionType

typedef Basic3DVector< float >	PositionType
	the helix is passed to the constructor and does not appear in the interface More...

Detailed Description

Calculates intersections of a helix with planes perpendicular to the z-axis.

Definition at line 13 of file HelixForwardPlaneCrossing.h.

Member Typedef Documentation

◆ DirectionTypeDouble

typedef Basic3DVector<double> HelixForwardPlaneCrossing::DirectionTypeDouble

private

Definition at line 54 of file HelixForwardPlaneCrossing.h.

◆ PositionTypeDouble

typedef Basic3DVector<double> HelixForwardPlaneCrossing::PositionTypeDouble

private

Definition at line 53 of file HelixForwardPlaneCrossing.h.

Constructor & Destructor Documentation

◆ HelixForwardPlaneCrossing()

HelixForwardPlaneCrossing::HelixForwardPlaneCrossing	(	const PositionType &	point,
		const DirectionType &	direction,
		const float	curvature,
		const PropagationDirection	propDir = `alongMomentum`
	)

Constructor using point, direction and (transverse!) curvature.

Definition at line 6 of file HelixForwardPlaneCrossing.cc.

     : theX0(point.x()),
       theY0(point.y()),
       theZ0(point.z()),
       theRho(curvature),
       thePropDir(propDir),
       theCachedS(0),
       theCachedDPhi(0.),
       theCachedSDPhi(0.),
       theCachedCDPhi(1.) {
   //
   // Components of direction vector (with correct normalisation)
   //
   double px = direction.x();
   double py = direction.y();
   double pz = direction.z();
   double pt2 = px * px + py * py;
   double p2 = pt2 + pz * pz;
   double pI = 1. / sqrt(p2);
   double ptI = 1. / sqrt(pt2);
   theCosPhi0 = px * ptI;
   theSinPhi0 = py * ptI;
   theCosTheta = pz * pI;
   theSinTheta = pt2 * ptI * pI;
 }

References direction(), p2, HLT_FULL_cff::pt2, multPhiCorr_741_25nsDY_cfi::px, multPhiCorr_741_25nsDY_cfi::py, mathSSE::sqrt(), theCosPhi0, theCosTheta, theSinPhi0, theSinTheta, Basic3DVector< T >::x(), Basic3DVector< T >::y(), and Basic3DVector< T >::z().

◆ ~HelixForwardPlaneCrossing()

HelixForwardPlaneCrossing::~HelixForwardPlaneCrossing ( )

inlineoverride

Definition at line 22 of file HelixForwardPlaneCrossing.h.

22 {}

Member Function Documentation

◆ direction()

HelixPlaneCrossing::DirectionType HelixForwardPlaneCrossing::direction ( double s ) const

overridevirtual

Direction at pathlength s from the starting point.

Implements HelixPlaneCrossing.

Definition at line 68 of file HelixForwardPlaneCrossing.cc.

                                                                                    {
   //
   // Calculate delta phi (if not already available)
   //
   if (s != theCachedS) {
     theCachedS = s;
     theCachedDPhi = theCachedS * theRho * theSinTheta;
     vdt::fast_sincos(theCachedDPhi, theCachedSDPhi, theCachedCDPhi);
   }
  
   if (fabs(theCachedDPhi) > 1.e-4) {
     // full helix formula
     return DirectionType(theCosPhi0 * theCachedCDPhi - theSinPhi0 * theCachedSDPhi,
                          theSinPhi0 * theCachedCDPhi + theCosPhi0 * theCachedSDPhi,
                          theCosTheta / theSinTheta);
   } else {
     // 2nd order
     double dph = theCachedS * theRho * theSinTheta;
     return DirectionType(theCosPhi0 - (theSinPhi0 + 0.5 * theCosPhi0 * dph) * dph,
                          theSinPhi0 + (theCosPhi0 - 0.5 * theSinPhi0 * dph) * dph,
                          theCosTheta / theSinTheta);
   }
 }

References MillePedeFileConverter_cfg::e, alignCSCRings::s, theCachedCDPhi, theCachedDPhi, theCachedS, theCachedSDPhi, theCosPhi0, theCosTheta, theRho, theSinPhi0, and theSinTheta.

Referenced by HelixForwardPlaneCrossing().

◆ pathLength()

std::pair<bool, double> HelixForwardPlaneCrossing::pathLength ( const Plane & plane )

inlineoverridevirtual

Propagation status (true if valid) and (signed) path length along the helix from the starting point to the plane.

Implements HelixPlaneCrossing.

Definition at line 27 of file HelixForwardPlaneCrossing.h.

                                                                 {
     //
     // Protect against p_z=0 and calculate path length
     //
     if
       UNLIKELY(std::abs(theCosTheta) < std::numeric_limits<float>::min()) return std::pair<bool, double>(false, 0);
  
     double dS = (plane.position().z() - theZ0) / theCosTheta;
  
     // negative logic to avoid checking for anyDirection...
     return std::make_pair(
         !(((thePropDir == alongMomentum) & (dS < 0.)) | ((thePropDir == oppositeToMomentum) & (dS > 0.))), dS);
   }

References funct::abs(), alongMomentum, min(), oppositeToMomentum, GloballyPositioned< T >::position(), theCosTheta, thePropDir, theZ0, UNLIKELY, and Basic3DVector< T >::z().

Referenced by CompositeTECWedge::computeCrossings(), TIDRing::computeCrossings(), and CompositeTECPetal::computeCrossings().

◆ position()

HelixPlaneCrossing::PositionType HelixForwardPlaneCrossing::position ( double s ) const

overridevirtual

Position at pathlength s from the starting point.

Implements HelixPlaneCrossing.

Definition at line 38 of file HelixForwardPlaneCrossing.cc.

                                                                                  {
   //
   // Calculate delta phi (if not already available)
   //
   if (s != theCachedS) {
     theCachedS = s;
     theCachedDPhi = theCachedS * theRho * theSinTheta;
     vdt::fast_sincos(theCachedDPhi, theCachedSDPhi, theCachedCDPhi);
   }
   //
   // Calculate with appropriate formulation of full helix formula or with
   //   2nd order approximation.
   //
   if (std::abs(theCachedDPhi) > 1.e-4) {
     // "standard" helix formula
     double o = 1. / theRho;
     return PositionTypeDouble(theX0 + (-theSinPhi0 * (1. - theCachedCDPhi) + theCosPhi0 * theCachedSDPhi) * o,
                               theY0 + (theCosPhi0 * (1. - theCachedCDPhi) + theSinPhi0 * theCachedSDPhi) * o,
                               theZ0 + theCachedS * theCosTheta);
   } else {
     // 2nd order
     double st = theCachedS * theSinTheta;
     return PositionType(theX0 + (theCosPhi0 - st * 0.5 * theRho * theSinPhi0) * st,
                         theY0 + (theSinPhi0 + st * 0.5 * theRho * theCosPhi0) * st,
                         theZ0 + st * theCosTheta / theSinTheta);
   }
 }