Belle II Software  release-05-02-19
InPhi0ImpactCurvBox Class Reference

Checker if a position is contained in a family of curves over phi0, impact and curvature. More...

#include <InPhi0ImpactCurvBox.h>

Public Types

using HoughBox = Box< DiscretePhi0, ContinuousImpact, DiscreteCurv >
 The box to which this object correspondes.
 

Public Member Functions

 InPhi0ImpactCurvBox (float curlCurv=NAN)
 Constructor taking the curler curvature Curlers with high curvature than the curler curvature may obtain hits from both arms.
 
ESign getDistanceSign (const HoughBox &houghBox, float x, float y, float l, float=0, float=0, ILayer=-1) const
 Function that gives the sign of the distance from an observed drift circle to the familiy of curves. More...
 

Private Attributes

float m_curlCurv
 Curler curvature - set to value greater zero to activate on arm exclusive finding.
 

Detailed Description

Checker if a position is contained in a family of curves over phi0, impact and curvature.

Definition at line 34 of file InPhi0ImpactCurvBox.h.

Member Function Documentation

◆ getDistanceSign()

ESign getDistanceSign ( const HoughBox houghBox,
float  x,
float  y,
float  l,
float  = 0,
float  = 0,
ILayer  = -1 
) const
inline

Function that gives the sign of the distance from an observed drift circle to the familiy of curves.

Returns
  • ESign::c_Plus if the drift circle is always on the positive / right site
  • ESign::c_Minus means the drift circle is always on the negative / left site
  • ESign::c_Zero if the dirft circle lies on any of the curves
  • ESign::c_Invalid if the drift cirlce is on the the wrong arm of the curve.

Definition at line 58 of file InPhi0ImpactCurvBox.h.

69  {
70  // Reject hit if it is on the inward going branch but the curvature suggest it is no curler
71  if (xRot[0] < 0 and xRot[1] < 0) return ESign::c_Invalid;
72  }
73 
74  std::array<float, 2> yRot;
75  yRot[0] = -x * phi0Vec[0]->y() + y * phi0Vec[0]->x();
76  yRot[1] = -x * phi0Vec[1]->y() + y * phi0Vec[1]->x();
77 
78  const std::array<ContinuousImpact, 2>& impact = houghBox.getBounds<ContinuousImpact>();
79 
80  // Using binary notation encoding lower and upper box bounds to fill the flat array.
81  std::array<float, 4> yRotMinusI;
82  yRotMinusI[0b00] = yRot[0] - impact[0];
83  yRotMinusI[0b01] = yRot[0] - impact[1];
84  yRotMinusI[0b10] = yRot[1] - impact[0];
85  yRotMinusI[0b11] = yRot[1] - impact[1];
86 
87  const float l2 = l * l;
88  std::array<float, 4> r2MinusI;
89  r2MinusI[0b00] = xRot[0] * xRot[0] + yRotMinusI[0b00] * yRotMinusI[0b00] - l2;
90  r2MinusI[0b01] = xRot[0] * xRot[0] + yRotMinusI[0b01] * yRotMinusI[0b01] - l2;
91  r2MinusI[0b10] = xRot[1] * xRot[1] + yRotMinusI[0b10] * yRotMinusI[0b10] - l2;
92  r2MinusI[0b11] = xRot[1] * xRot[1] + yRotMinusI[0b11] * yRotMinusI[0b11] - l2;
93 
94 
95  // Using binary notation encoding lower and upper box bounds to fill the flat array.
96  std::array<ESign, 2> distSign;
97  for (int c_Curv = 0; c_Curv < 2; ++c_Curv) {
98  std::array<float, 4> dist;
99  float curvHalf = static_cast<float>(curv[c_Curv]) / 2;
100  dist[0b00] = - yRotMinusI[0b00] + r2MinusI[0b00] * curvHalf - l;
101  dist[0b01] = - yRotMinusI[0b01] + r2MinusI[0b01] * curvHalf - l;
102  dist[0b10] = - yRotMinusI[0b10] + r2MinusI[0b10] * curvHalf - l;
103  dist[0b11] = - yRotMinusI[0b11] + r2MinusI[0b11] * curvHalf - l;
104  distSign[c_Curv] = ESignUtil::common(dist);
105  }
106 
107  return ESignUtil::common(distSign[0], distSign[1]);
108 
109  }
110 
111  private:
113  float m_curlCurv;
114  };
115  }
117 }

The documentation for this class was generated from the following file:
Belle2::TrackFindingCDC::ESignUtil::common
static ESign common(ESign n1, ESign n2)
Check if two values have a common sign.
Definition: ESign.h:67
Belle2::TrackFindingCDC::NHelixParameterIndices::c_Curv
@ c_Curv
Constant to address the curvature in the xy plane.
Definition: HelixParameters.h:39
Belle2::TrackFindingCDC::InPhi0ImpactCurvBox::m_curlCurv
float m_curlCurv
Curler curvature - set to value greater zero to activate on arm exclusive finding.
Definition: InPhi0ImpactCurvBox.h:121