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VertexKinematicConstraint Class Reference

Class implementing the vertexing constraint for extended cartesian parametrization (x,y,z,p_x,p_y,p_z,m). More...

#include <RecoVertex/KinematicFit/interface/VertexKinematicConstraint.h>

Inheritance diagram for VertexKinematicConstraint:

MultiTrackKinematicConstraint

List of all members.

Public Member Functions

virtual VertexKinematicConstraint * clone () const
virtual int numberOfEquations () const
 Number of equations per track used for the fit.
virtual AlgebraicMatrix parametersDerivative (const vector< KinematicState > states, const GlobalPoint &point) const
 Returns a matrix of derivatives of constraint equations w.r.t.
virtual AlgebraicMatrix positionDerivative (const vector< KinematicState > states, const GlobalPoint &point) const
 Returns a matrix of derivatives of constraint equations w.r.t.
virtual AlgebraicVector value (const vector< KinematicState > states, const GlobalPoint &point) const
 Returns a vector of values of constraint equations at the point where the input particles are defined.
 VertexKinematicConstraint ()
virtual ~VertexKinematicConstraint ()

Detailed Description

Class implementing the vertexing constraint for extended cartesian parametrization (x,y,z,p_x,p_y,p_z,m).

The equations and derivatives in general follow the P.Avery's "Applied Fitting Theory-VI" CBX 98-37

Definition at line 14 of file VertexKinematicConstraint.h.

Constructor & Destructor Documentation

VertexKinematicConstraint::VertexKinematicConstraint (  ) 

Definition at line 4 of file VertexKinematicConstraint.cc.

Referenced by clone().

00005 {}

VertexKinematicConstraint::~VertexKinematicConstraint (  )  [virtual]

Definition at line 7 of file VertexKinematicConstraint.cc.

00008 {}

Member Function Documentation

virtual VertexKinematicConstraint* VertexKinematicConstraint::clone ( void   )  const [inline, virtual]

Implements MultiTrackKinematicConstraint.

Definition at line 50 of file VertexKinematicConstraint.h.

References VertexKinematicConstraint().

00051 {return new VertexKinematicConstraint(*this);}

int VertexKinematicConstraint::numberOfEquations (  )  const [virtual]

Number of equations per track used for the fit.

Implements MultiTrackKinematicConstraint.

Definition at line 156 of file VertexKinematicConstraint.cc.

00157 {return 2;}

AlgebraicMatrix VertexKinematicConstraint::parametersDerivative ( const vector< KinematicState >  states,
const GlobalPoint &  point 
) const [virtual]

Returns a matrix of derivatives of constraint equations w.r.t.

particle parameters

Implements MultiTrackKinematicConstraint.

Definition at line 50 of file VertexKinematicConstraint.cc.

References i, j, funct::num(), s, funct::sqrt(), PV3DBase< T, PVType, FrameType >::transverse(), PV3DBase< T, PVType, FrameType >::x(), PV3DBase< T, PVType, FrameType >::y(), and PV3DBase< T, PVType, FrameType >::z().

Referenced by KinematicConstrainedVertexUpdator::update().

00052 {
00053  int num = states.size();
00054  if(num<2) throw VertexException("VertexKinematicConstraint::<2 states passed");
00055  AlgebraicMatrix jac_d(2*num,7*num);
00056  int num_r = 0;
00057  for(vector<KinematicState>::const_iterator i = states.begin(); i != states.end(); i++)
00058  {
00059   AlgebraicMatrix el_part_d(2,7,0);
00060   TrackCharge ch = i->particleCharge();
00061   GlobalVector mom = i->globalMomentum();
00062   GlobalPoint pos =  i->globalPosition();
00063   double d_x = point.x() - pos.x();
00064   double d_y = point.y() - pos.y();
00065   double pt = mom.transverse();
00066   
00067   if(ch !=0){
00068   
00069 //charged particle  
00070    double field = i->magneticField()->inInverseGeV(pos).z();
00071    double a_i = -0.29979246*ch*field;
00072    double j = a_i*(d_x * mom.x() + d_y * mom.y())/(pt*pt);
00073    double r_x = d_x - 2* mom.x()*(d_x*mom.x()+d_y*mom.y())/(pt*pt);
00074    double r_y = d_x - 2* mom.y()*(d_x*mom.x()+d_y*mom.y())/(pt*pt);
00075    double s = 1/(pt*pt*sqrt(1 - j*j)); 
00076 
00077 //D Jacobian matrix  
00078    el_part_d(1,1) =  mom.y() + a_i*d_x;
00079    el_part_d(1,2) = -mom.x() + a_i*d_y;
00080    el_part_d(2,1) =  mom.x() * mom.z() * s;
00081    el_part_d(2,2) =  mom.y() * mom.z() * s;
00082    el_part_d(2,3) = -1.;
00083    el_part_d(1,4) = d_y;
00084    el_part_d(1,5) = -d_x;
00085    el_part_d(2,4) = -mom.z()*s*r_x;
00086    el_part_d(2,5) = -mom.z()*s*r_y;
00087    el_part_d(2,6) = -asin(j) /a_i;
00088    jac_d.sub(num_r*2+1, num_r*7+1, el_part_d);
00089   }else{
00090 //neutral particle  
00091    el_part_d(1,1) =  mom.y();
00092    el_part_d(1,2) = -mom.x();
00093    el_part_d(2,1) =  mom.x() * mom.z()/(pt*pt);
00094    el_part_d(2,2) =  mom.y() * mom.z()/(pt*pt);
00095    el_part_d(2,3) = -1.;
00096    el_part_d(1,4) = d_y;
00097    el_part_d(1,5) = -d_x;
00098    el_part_d(2,4) = 2*(d_x*mom.x()+d_y*mom.y())*mom.x()*mom.z()/(pt*pt*pt*pt) - mom.z()*d_x/(pt*pt);
00099    el_part_d(2,5) = 2*(d_x*mom.x()+d_y*mom.y())*mom.y()*mom.z()/(pt*pt*pt*pt) - mom.z()*d_y/(pt*pt);
00100    el_part_d(2,6) =-(d_x * mom.x() + d_y * mom.y())/(pt*pt);
00101    jac_d.sub(num_r*2+1, num_r*7+1, el_part_d);
00102   } 
00103   num_r++;
00104  } 
00105  return jac_d;
00106 }

AlgebraicMatrix VertexKinematicConstraint::positionDerivative ( const vector< KinematicState >  states,
const GlobalPoint &  point 
) const [virtual]

Returns a matrix of derivatives of constraint equations w.r.t.

vertex position

Implements MultiTrackKinematicConstraint.

Definition at line 108 of file VertexKinematicConstraint.cc.

References i, j, funct::num(), s, funct::sqrt(), PV3DBase< T, PVType, FrameType >::transverse(), PV3DBase< T, PVType, FrameType >::x(), PV3DBase< T, PVType, FrameType >::y(), and PV3DBase< T, PVType, FrameType >::z().

Referenced by KinematicConstrainedVertexUpdator::update().

00110 { 
00111  int num = states.size();
00112  if(num<2) throw VertexException("VertexKinematicConstraint::<2 states passed");
00113  AlgebraicMatrix jac_e(2*num,3);
00114  int num_r = 0;
00115  for(vector<KinematicState>::const_iterator i = states.begin(); i != states.end(); i++)
00116  {
00117   AlgebraicMatrix el_part_e(2,3,0);
00118   TrackCharge ch = i->particleCharge();
00119   GlobalVector mom = i->globalMomentum();
00120   GlobalPoint pos =  i->globalPosition();
00121   double d_x = point.x() - pos.x();
00122   double d_y = point.y() - pos.y();
00123   double pt = mom.transverse();
00124   
00125   if(ch !=0 )
00126   {
00127   
00128 //charged particle  
00129    double field = i->magneticField()->inInverseGeV(pos).z();
00130    double a_i = -0.29979246*ch*field;
00131    double j = a_i*(d_x * mom.x() + d_y * mom.y())/(pt*pt);
00132    double s = 1/(pt*pt*sqrt(1 - j*j));
00133 
00134 //E jacobian matrix 
00135    el_part_e(1,1) = -(mom.y() + a_i*d_x);
00136    el_part_e(1,2) = mom.x() - a_i*d_y;
00137    el_part_e(2,1) = -mom.x()*mom.z()*s;
00138    el_part_e(2,2) = -mom.y()*mom.z()*s;
00139    el_part_e(2,3) = 1;
00140    jac_e.sub(2*num_r+1,1,el_part_e);
00141   }else{
00142   
00143 //neutral particle 
00144    el_part_e(1,1) = - mom.y();
00145    el_part_e(1,2) = mom.x();
00146    el_part_e(2,1) = -mom.x()*mom.z()/(pt*pt);
00147    el_part_e(2,2) = -mom.y()*mom.z()/(pt*pt);
00148    el_part_e(2,3) = 1;
00149    jac_e.sub(2*num_r+1,1,el_part_e);
00150   }
00151   num_r++;
00152  }
00153  return jac_e;
00154 }

AlgebraicVector VertexKinematicConstraint::value ( const vector< KinematicState >  states,
const GlobalPoint &  point 
) const [virtual]

Returns a vector of values of constraint equations at the point where the input particles are defined.

Implements MultiTrackKinematicConstraint.

Definition at line 10 of file VertexKinematicConstraint.cc.

References i, j, funct::num(), PV3DBase< T, PVType, FrameType >::transverse(), PV3DBase< T, PVType, FrameType >::x(), PV3DBase< T, PVType, FrameType >::y(), and PV3DBase< T, PVType, FrameType >::z().

Referenced by KinematicConstrainedVertexFitter::fit(), and KinematicConstrainedVertexUpdator::update().

00012 {
00013  int num = states.size();
00014  if(num<2) throw VertexException("VertexKinematicConstraint::<2 states passed");
00015  
00016 //it is 2 equations per track  
00017  AlgebraicVector  vl(2*num,0);
00018  int num_r = 0;
00019  for(vector<KinematicState>::const_iterator i = states.begin(); i != states.end(); i++)
00020  {
00021   TrackCharge ch = i->particleCharge();
00022   GlobalVector mom = i->globalMomentum();
00023   GlobalPoint pos =  i->globalPosition();
00024   double d_x = point.x() - pos.x();
00025   double d_y = point.y() - pos.y();
00026   double d_z = point.z() - pos.z();
00027   double pt = mom.transverse();
00028   if(ch !=0)
00029   {
00030 
00031 //charged particle  
00032    double field = i->magneticField()->inInverseGeV(pos).z();
00033    double a_i = -0.29979246*ch*field;
00034    double j = a_i*(d_x * mom.x() + d_y * mom.y())/(pt*pt);
00035  
00036 //vector of values  
00037    vl(num_r*2 +1) = d_y*mom.x() - d_x*mom.y() -a_i*(d_x*d_x + d_y*d_y)/2;
00038    vl(num_r*2 +2) = d_z - mom.z()*asin(j)/a_i;  
00039   }else{
00040   
00041 //neutral particle
00042    vl(num_r*2 +1) = d_y*mom.x() - d_x*mom.y();
00043    vl(num_r*2 +2) = d_z - mom.z()*(d_x * mom.x() + d_y * mom.y())/(pt*pt);
00044   }
00045   num_r++;
00046  }
00047  return vl;
00048 }

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