SelVarHelper< PointType, DataType > Struct Template Reference

contains a collection of functions and related stuff needed for SelectionVariables implementing 2-, 3- and 4-hitfilters. More...

#include <SelectionVariableHelper.h>

Static Public Member Functions
static void	resetMagneticField (DataType magneticFieldStrength=1.5)
	Overrides standard-Setup for magnetic field.
static DataType	calcPerp2 (const PointType &aHit)
	returns the perpendicular magnitude squared of given pointType.
static DataType	calcPerp (const PointType &aHit)
	returns the perpendicular magnitude of given pointType.
static DataType	calcMag2 (const PointType &aHit)
	returns the magnitude squared of given pointType.
static DataType	calcMag (const PointType &aHit)
	returns the magnitude of given pointType.
static DataType	calcDot (const PointType &aHit, const PointType &bHit)
	returns scalar product of given two pointTypes.
static DataType	calcPt (DataType radius, DataType field=SelVarHelper::s_MagneticFieldFactor)
	calculates the estimation of the transverse momentum of given radius using defined strength of magnetic field, returning unit: GeV/c.

Static Public Attributes
static DataType	s_MagneticFieldFactor
	is factor containing speed of light (c), the magnetic field (b) and the scaling factor s for conversion of meter in cm : c*b/100 = c*b*s.

Detailed Description

template<class PointType, class DataType>
struct Belle2::SelVarHelper< PointType, DataType >

contains a collection of functions and related stuff needed for SelectionVariables implementing 2-, 3- and 4-hitfilters.

Template PointType expects a class having the functions X(), Y() and Z() returning Datatype. Template DataType should behave like a primitive like double or float.

Definition at line 21 of file SelectionVariableHelper.h.

Member Function Documentation

calcDot()

template<class PointType, class DataType>

static DataType calcDot ( const PointType & aHit, const PointType & bHit )

inlinestatic

returns scalar product of given two pointTypes.

Definition at line 59 of file SelectionVariableHelper.h.

    { return (aHit.X() * bHit.X() + aHit.Y() * bHit.Y() + aHit.Z() * bHit.Z()); }

calcMag()

template<class PointType, class DataType>

static DataType calcMag ( const PointType & aHit )

inlinestatic

returns the magnitude of given pointType.

Definition at line 55 of file SelectionVariableHelper.h.

{ return sqrt(calcMag2(aHit)); }

calcMag2()

template<class PointType, class DataType>

static DataType calcMag2 ( const PointType & aHit )

inlinestatic

returns the magnitude squared of given pointType.

Definition at line 50 of file SelectionVariableHelper.h.

    { return (aHit.X() * aHit.X() + aHit.Y() * aHit.Y() + aHit.Z() * aHit.Z()); }

calcPerp()

template<class PointType, class DataType>

static DataType calcPerp ( const PointType & aHit )

inlinestatic

returns the perpendicular magnitude of given pointType.

Definition at line 46 of file SelectionVariableHelper.h.

{ return sqrt(calcPerp2(aHit)); }

calcPerp2()

template<class PointType, class DataType>

static DataType calcPerp2 ( const PointType & aHit )

inlinestatic

returns the perpendicular magnitude squared of given pointType.

Definition at line 41 of file SelectionVariableHelper.h.

    { return (aHit.X() * aHit.X() + aHit.Y() * aHit.Y()); }

calcPt()

template<class PointType, class DataType>

static DataType calcPt ( DataType radius, DataType field = SelVarHelper< PointType, DataType >::s_MagneticFieldFactor )

inlinestatic

calculates the estimation of the transverse momentum of given radius using defined strength of magnetic field, returning unit: GeV/c.

Definition at line 63 of file SelectionVariableHelper.h.

    {
      // TODO WARNING hardcoded value, is there a quasi-global value for such cases (this case, minimal accepted radius)
      // if (fabs(radius) < 0.0000001) { throw (Circle_too_small() << radius << 0.0000001); }
 
      //WARNING: does not care for negative radius!!
      return field * radius;
    } // return unit: GeV/c

resetMagneticField()

template<class PointType, class DataType>

static void resetMagneticField ( DataType magneticFieldStrength = 1.5 )

inlinestatic

Overrides standard-Setup for magnetic field.

If no value is given, magnetic field is assumed to be Belle2-Detector standard of 1.5T. pT[GeV/c] = 0.299710*B[T]*r[m] = 0.299710*B[T]*r[cm]/100 = 0.00299710B[T]*r[cm].

Definition at line 37 of file SelectionVariableHelper.h.

{ SelVarHelper::s_MagneticFieldFactor = magneticFieldStrength * 0.00299710; }

Member Data Documentation

s_MagneticFieldFactor

template<class PointType, class DataType>

DataType s_MagneticFieldFactor

static

is factor containing speed of light (c), the magnetic field (b) and the scaling factor s for conversion of meter in cm : c*b/100 = c*b*s.

The standard value assumes a magnetic field of 1.5 Tesla. Value can be changed using the resetMagneticField-Function, where a new value for the magnetic field in Tesla has to be passed. TODO WARNING hardcoded value!

Definition at line 29 of file SelectionVariableHelper.h.

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The documentation for this struct was generated from the following file:

• tracking/trackFindingVXD/filterTools/include/SelectionVariableHelper.h