StHelix Class Reference

#include <StHelix.hh>

Inherited by StPhysicalHelix.

List of all members.

Public Member Functions

 StHelix (double c, double dip, double phase, const StThreeVector< double > &o, int h=-1)
 curvature, dip angle, phase, origin, h
double dipAngle () const
double curvature () const
double phase () const
 1/R in xy-plane
double xcenter () const
 aziumth in xy-plane measured from ring center
double ycenter () const
 x-center of circle in xy-plane
int h () const
 y-center of circle in xy-plane
const StThreeVector< double > & origin () const
 -sign(q*B);
void setParameters (double c, double dip, double phase, const StThreeVector< double > &o, int h)
 starting point
double x (double s) const
 coordinates of helix at point s
double y (double s) const
double z (double s) const
StThreeVector< double > at (double s) const
double cx (double s) const
 pointing vector of helix at point s
double cy (double s) const
double cz (double s=0) const
StThreeVector< double > cat (double s) const
double period () const
 returns period length of helix
pair< double, double > pathLength (double r) const
 path length at given r (cylindrical r)
pair< double, double > pathLength (double r, double x, double y)
 path length at given r (cylindrical r, cylinder axis at x,y)
double pathLength (const StThreeVector< double > &p, bool scanPeriods=true) const
 path length at distance of closest approach to a given point
double pathLength (const StThreeVector< double > &r, const StThreeVector< double > &n) const
 path length at intersection with plane
double pathLength (double x, double y) const
 path length at distance of closest approach in the xy-plane to a given point
pair< double, double > pathLengths (const StHelix &) const
 path lengths at dca between two helices
double distance (const StThreeVector< double > &p, bool scanPeriods=true) const
 minimal distance between point and helix
bool valid (double world=1.e+5) const
 checks for valid parametrization
int bad (double world=1.e+5) const
virtual void moveOrigin (double s)
 move the origin along the helix to s which becomes then s=0

Static Public Attributes

static const double NoSolution = 3.e+33

Protected Member Functions

void setCurvature (double)
void setPhase (double)
 performs also various checks
void setDipAngle (double)
double fudgePathLength (const StThreeVector< double > &) const
 value of S where distance in x-y plane is minimal

Protected Attributes

bool mSingularity
StThreeVector< double > mOrigin
double mDipAngle
double mCurvature
double mPhase
int mH
double mCosDipAngle
double mSinDipAngle
double mCosPhase
double mSinPhase


Detailed Description

Author:
Thomas Ullrich, Sep 26 1997
Parametrization of a helix. Can also cope with straight tracks, i.e. with zero curvature. This represents only the mathematical model of a helix. See the SCL user guide for more.

Definition at line 61 of file StHelix.hh.


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

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