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BackToBackKinematicConstraint Class Reference

Class implementing the back-to-back geometry constraints for 2 KinematicParticles. More...

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

Inheritance diagram for BackToBackKinematicConstraint:

KinematicConstraint

List of all members.

Public Member Functions

 BackToBackKinematicConstraint ()
virtual KinematicConstraint * clone () const
 Clone method.
virtual pair< AlgebraicMatrix,
AlgebraicVector > 		derivative (const vector< RefCountedKinematicParticle > par) const
virtual pair< AlgebraicMatrix,
AlgebraicVector > 		derivative (const AlgebraicVector &exPoint) const
virtual AlgebraicVector deviations (int nStates) const
 Returns vector of sigma squared associated to the KinematicParameters of refitted particles Initial deviations are given by user for the constraining parameters (mass, momentum components etc).
virtual int numberOfEquations () const
 Returns an actual number of equations in particular constraint (corresponds to the number of strings in constraint derivative matrix, for example).
virtual pair< AlgebraicVector,
AlgebraicVector > 		value (const vector< RefCountedKinematicParticle > par) const
 Derivatives and values calculated at expansion point, taken at current state of input particles.
virtual pair< AlgebraicVector,
AlgebraicVector > 		value (const AlgebraicVector &exPoint) const
 Derivatives and value calculated at given expansion point Vector should always be of size 14 (2 particles).
 ~BackToBackKinematicConstraint ()

Detailed Description

Class implementing the back-to-back geometry constraints for 2 KinematicParticles.

Current version does not implement an actual back-to-back. Current class forces 2 tracks to have the opposite direction, bud does not force them to emerge from the single point. Coorect version to be implemented later.

This is just an illustrative piece of code, showing possible approach to constraint application on multiple tracks.

Kirill Prokofiev, July 2004

Definition at line 21 of file BackToBackKinematicConstraint.h.

Constructor & Destructor Documentation

BackToBackKinematicConstraint::BackToBackKinematicConstraint (  )  [inline]

Definition at line 25 of file BackToBackKinematicConstraint.h.

Referenced by clone().

00025 {}

BackToBackKinematicConstraint::~BackToBackKinematicConstraint (  )  [inline]

Definition at line 27 of file BackToBackKinematicConstraint.h.

00027 {}

Member Function Documentation

KinematicConstraint * BackToBackKinematicConstraint::clone (  )  const [virtual]

Clone method.

Implements KinematicConstraint.

Definition at line 86 of file BackToBackKinematicConstraint.cc.

References BackToBackKinematicConstraint().

00087 {return new BackToBackKinematicConstraint(*this);}

pair< AlgebraicMatrix, AlgebraicVector > BackToBackKinematicConstraint::derivative ( const vector< RefCountedKinematicParticle >  par  )  const [virtual]

Implements KinematicConstraint.

Definition at line 60 of file BackToBackKinematicConstraint.cc.

References i, and j.

00061 {
00062  int nStates = par.size();
00063  if(nStates != 2) throw VertexException("BackToBackKinematicConstraint::number of tracks is not equal to 2"); 
00064  AlgebraicVector point(14,0);
00065  int co = 0;
00066  for(vector<RefCountedKinematicParticle>::const_iterator i = par.begin(); i!=par.end(); i++)
00067  {
00068   AlgebraicVector7 cPar = (*i)->currentState().kinematicParameters().vector();
00069   for(int j = 1; j<8; j++){point((co-1)*7+j) = cPar(j-1);}
00070   co++;
00071  }
00072  AlgebraicMatrix dr(3,14,0);
00073 
00074  return pair<AlgebraicMatrix, AlgebraicVector>(dr,point);
00075 }

pair< AlgebraicMatrix, AlgebraicVector > BackToBackKinematicConstraint::derivative ( const AlgebraicVector &  exPoint  )  const [virtual]

Implements KinematicConstraint.

Definition at line 20 of file BackToBackKinematicConstraint.cc.

00021 {
00022 //security check for extended cartesian parametrization 
00023  int inSize = exPoint.num_row(); 
00024  if(inSize != 14) throw VertexException("BackToBackKinematicConstraint::linearization point has a wrong dimension");
00025  AlgebraicVector pr = exPoint;
00026  
00027 //number of states should be always equal to 2 for such a constraint 
00028  AlgebraicMatrix dr(3,14,0);
00029  dr(1,4) = 1.;
00030  dr(1,11) = 1.;
00031  dr(2,5) = 1;
00032  dr(2,12) = 1;
00033  dr(3,6) = 1;
00034  dr(3,13) = 1;
00035  return pair<AlgebraicMatrix, AlgebraicVector>(dr,pr); 
00036 }

AlgebraicVector BackToBackKinematicConstraint::deviations ( int  nStates  )  const [virtual]

Returns vector of sigma squared associated to the KinematicParameters of refitted particles Initial deviations are given by user for the constraining parameters (mass, momentum components etc).

In case of multiple states exactly the same values are added to every particle parameters

Implements KinematicConstraint.

Definition at line 77 of file BackToBackKinematicConstraint.cc.

References dd.

00078 {
00079  AlgebraicVector dd(7*nStates,0);
00080  return dd;
00081 }

int BackToBackKinematicConstraint::numberOfEquations (  )  const [virtual]

Returns an actual number of equations in particular constraint (corresponds to the number of strings in constraint derivative matrix, for example).

Implements KinematicConstraint.

Definition at line 83 of file BackToBackKinematicConstraint.cc.

00084 {return 3;}

pair< AlgebraicVector, AlgebraicVector > BackToBackKinematicConstraint::value ( const vector< RefCountedKinematicParticle >  par  )  const [virtual]

Derivatives and values calculated at expansion point, taken at current state of input particles.

Number of input particles should be always equal to 2

Implements KinematicConstraint.

Definition at line 38 of file BackToBackKinematicConstraint.cc.

References i, and j.

00039 {
00040  int nStates = par.size();
00041  if(nStates != 2) throw VertexException("BackToBackKinematicConstraint::number of tracks is not equal to 2");
00042  AlgebraicVector point(14,0);
00043  int co = 0;
00044  for(vector<RefCountedKinematicParticle>::const_iterator i = par.begin(); i!=par.end(); i++)
00045  {
00046   AlgebraicVector7 cPar = (*i)->currentState().kinematicParameters().vector();
00047   for(int j = 1; j<8; j++){point((co-1)*7+j) = cPar(j-1);}
00048   co++;
00049  }
00050  AlgebraicVector vl(3,0);
00051  AlgebraicVector st1 = asHepVector<7>(par[0]->currentState().kinematicParameters().vector());
00052  AlgebraicVector st2 = asHepVector<7>(par[1]->currentState().kinematicParameters().vector());
00053  vl(1) = st1(4)+st2(4);
00054  vl(2) = st1(5)+st2(5);
00055  vl(3) = st1(6)+st2(6);
00056  
00057  return pair<AlgebraicVector, AlgebraicVector>(vl,point); 
00058 }

pair< AlgebraicVector, AlgebraicVector > BackToBackKinematicConstraint::value ( const AlgebraicVector &  exPoint  )  const [virtual]

Derivatives and value calculated at given expansion point Vector should always be of size 14 (2 particles).

Implements KinematicConstraint.

Definition at line 5 of file BackToBackKinematicConstraint.cc.

00006 {
00007 //security check for extended cartesian parametrization 
00008  int inSize = exPoint.num_row(); 
00009  if(inSize != 14) throw VertexException("BackToBackKinematicConstraint::linearization point has a wrong dimension");
00010  AlgebraicVector pr = exPoint;
00011  
00012 //number of states should be always equal to 2 for such a constraint
00013  AlgebraicVector vl(3,0);
00014  vl(1) = pr(4)+pr(11);
00015  vl(2) = pr(5)+pr(12);
00016  vl(3) = pr(6)+pr(13);
00017  return pair<AlgebraicVector, AlgebraicVector>(vl,pr); 
00018 }

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