genfit::HelixTrackModel Class Reference

Helix track model for testing purposes. More...

#include <HelixTrackModel.h>

Inheritance diagram for genfit::HelixTrackModel:

Collaboration diagram for genfit::HelixTrackModel:

Public Member Functions
	HelixTrackModel (const TVector3 &pos, const TVector3 &mom, double charge)
TVector3	getPos (double tracklength) const
void	getPosMom (double tracklength, TVector3 &pos, TVector3 &mom) const
void	getPosDir (double tracklength, TVector3 &pos, TVector3 &dir) const

Private Attributes
double	sgn_
double	mom_
double	R_
TVector3	center_
double	alpha0_
double	theta_

Detailed Description

Helix track model for testing purposes.

Definition at line 41 of file HelixTrackModel.h.

Constructor & Destructor Documentation

HelixTrackModel()

genfit::HelixTrackModel::HelixTrackModel	(	const TVector3 &	pos,
		const TVector3 &	mom,
		double	charge
	)

Definition at line 28 of file HelixTrackModel.cc.

                                                                                        {
 
  mom_ = mom.Mag();
 
  TVector3 B = genfit::FieldManager::getInstance()->getFieldVal(pos);
  std::cout<<"check  " << B.Y() << "\n";
  // B must point in Z direction
  // assert(B.X() == 0);
  // assert(B.Y() == 0);
 
  double Bz = B.Z();
 
  // calc helix parameters
  TVector3 dir2D(mom);
  dir2D.SetZ(0);
  dir2D.SetMag(1.);
  R_ = 100.*mom.Perp()/(0.0299792458*Bz) / fabs(charge);
  sgn_ = 1;
  if (charge<0) sgn_=-1.;
  center_ = pos + sgn_ * R_ * dir2D.Orthogonal();
  alpha0_ = (pos-center_).Phi();
 
  theta_ = mom.Theta();
 
  //std::cout<<"radius " << R_ << "  center ";
  //center_.Print();
 
}

Member Function Documentation

getPos()

TVector3 genfit::HelixTrackModel::getPos

(

double

tracklength

)

const

Definition at line 58 of file HelixTrackModel.cc.

                                                         {
 
  TVector3 pos;
 
  double angle = alpha0_ - sgn_ * tracklength / R_ * sin(theta_);
 
  TVector3 radius(R_,0,0);
  radius.SetPhi(angle);
  pos = center_ + radius;
  pos.SetZ(center_.Z() - sgn_ * ((alpha0_-angle)*R_ * tan(theta_-M_PI/2.)) );
 
  return pos;
}

getPosDir()

void genfit::HelixTrackModel::getPosDir ( double  tracklength, TVector3 &  pos, TVector3 &  dir  ) const

inline

Definition at line 50 of file HelixTrackModel.h.

                                                                         {
    getPosMom(tracklength, pos, dir);
    dir.SetMag(1);
  }

getPosMom()

void genfit::HelixTrackModel::getPosMom	(	double	tracklength,
		TVector3 &	pos,
		TVector3 &	mom
	)		const

Definition at line 72 of file HelixTrackModel.cc.

                                                                                      {
 
  double angle = alpha0_ - sgn_ * tracklength / R_ * sin(theta_);
 
  TVector3 radius(R_,0,0);
  radius.SetPhi(angle);
  pos = center_ + radius;
  pos.SetZ(center_.Z() - sgn_ * ((alpha0_-angle)*R_ * tan(theta_-M_PI/2.)) );
 
  mom.SetXYZ(1,1,1);
  mom.SetTheta(theta_);
  mom.SetPhi(angle - sgn_*M_PI/2.);
  mom.SetMag(mom_);
 
  /*std::cout<<"tracklength " << tracklength << "\n";
  std::cout<<"angle " << angle << "\n";
  std::cout<<"radius vector "; radius.Print();
  std::cout<<"pos "; pos.Print();
  std::cout<<"mom "; mom.Print();*/
 
}

Member Data Documentation

alpha0_

double genfit::HelixTrackModel::alpha0_

private

Definition at line 62 of file HelixTrackModel.h.

center_

TVector3 genfit::HelixTrackModel::center_

private

Definition at line 61 of file HelixTrackModel.h.

mom_

double genfit::HelixTrackModel::mom_

private

Definition at line 59 of file HelixTrackModel.h.

R_

double genfit::HelixTrackModel::R_

private

Definition at line 60 of file HelixTrackModel.h.

sgn_

double genfit::HelixTrackModel::sgn_

private

Definition at line 58 of file HelixTrackModel.h.

theta_

double genfit::HelixTrackModel::theta_

private

Definition at line 63 of file HelixTrackModel.h.

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

• genfit/utilities/include/HelixTrackModel.h
• genfit/utilities/src/HelixTrackModel.cc