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FourMomentumKinematicConstraint Class Reference

4-Momentum track constraint class provides a way to compute the matrix of derivatives and the vector of values for 4-Momentum constraint on for given KinematicParticle. More...

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

Inheritance diagram for FourMomentumKinematicConstraint:

List of all members.

Public Member Functions
virtual FourMomentumKinematicConstraint *	clone () const
	Clone method.
virtual pair< AlgebraicMatrix, AlgebraicVector >	derivative (const vector< RefCountedKinematicParticle > par) const
	Vector of values and matrix of derivatives calculated using current state as an expansion point.
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).
	FourMomentumKinematicConstraint (const AlgebraicVector &momentum, const AlgebraicVector &deviation)
	Constructor with desired 4-momentum vector and vector of deviations to be used forcovariance matrix as arguments.
virtual int	numberOfEquations () const
	Returns number of constraint equations used for fitting.
virtual pair< AlgebraicVector, AlgebraicVector >	value (const vector< RefCountedKinematicParticle > par) const
	Methods making value and derivative matrix using current state parameters as expansion 7-point.
virtual pair< AlgebraicVector, AlgebraicVector >	value (const AlgebraicVector &exPoint) const
	Vector of values and matrix of derivatives calculated at given 7*NumberOfStates expansion point.
Private Attributes
AlgebraicVector	dd
AlgebraicVector	mm

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Detailed Description

4-Momentum track constraint class provides a way to compute the matrix of derivatives and the vector of values for 4-Momentum constraint on for given KinematicParticle.

Current version does not allow working with multiple tracks

Kirill Prokofiev March 2003 MultiState version: July 2004

Definition at line 17 of file FourMomentumKinematicConstraint.h.

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Constructor & Destructor Documentation

FourMomentumKinematicConstraint::FourMomentumKinematicConstraint	(	const AlgebraicVector &	momentum,
		const AlgebraicVector &	deviation
	)

Constructor with desired 4-momentum vector and vector of deviations to be used forcovariance matrix as arguments.

Definition at line 5 of file FourMomentumKinematicConstraint.cc.

References dd, and mm.

Referenced by clone().

{
 if((momentum.num_row() != 4)||(deviation.num_row() != 4)) 
  throw VertexException("FourMomentumKinematicConstraint::vector of wrong size passed as 4-Momentum or Deviations");
 mm = momentum; 
 AlgebraicVector deviation_l(7,0);
 deviation_l(6) = momentum(3);
 deviation_l(5) = momentum(2);
 deviation_l(4) = momentum(1);
  
 double mass_sq = momentum(4)*momentum(4) - momentum(3)*momentum(3)
                -momentum(2)*momentum(2) - momentum(1)*momentum(1); 

 if(mass_sq == 0.)throw VertexException("FourMomentumKinematicConstraint::the constraint vector passed corresponds to 0 mass");
//deviation for mass calculated from deviations
//of momentum
 deviation_l(7) = momentum(4)*momentum(4)*deviation(4)/mass_sq 
                + momentum(3)*momentum(3)*deviation(3)/mass_sq
                + momentum(2)*momentum(2)*deviation(2)/mass_sq
                + momentum(1)*momentum(1)*deviation(1)/mass_sq;
//mass sigma because of the energy 
 
 dd = deviation_l;
}

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Member Function Documentation

virtual FourMomentumKinematicConstraint* FourMomentumKinematicConstraint::clone

(

)

const [inline, virtual]

Clone method.

Implements KinematicConstraint.

Definition at line 56 of file FourMomentumKinematicConstraint.h.

References FourMomentumKinematicConstraint().

 {return new FourMomentumKinematicConstraint(*this);}

pair< AlgebraicMatrix, AlgebraicVector > FourMomentumKinematicConstraint::derivative

(

const vector< RefCountedKinematicParticle >

par

)

const [virtual]

Vector of values and matrix of derivatives calculated using current state as an expansion point.

Implements KinematicConstraint.

Definition at line 86 of file FourMomentumKinematicConstraint.cc.

References funct::sqrt().

{
 int nStates = par.size();
 if(nStates == 0) throw VertexException("FourMomentumKinematicConstraint::Empty vector of particles passed");
 if(nStates != 1) throw VertexException("FourMomentumKinematicConstraint::Multi particle refit is not supported in this version");
 AlgebraicMatrix dr(4,7,0);
 
 AlgebraicVector pr = asHepVector<7>(par.front()->currentState().kinematicParameters().vector());
 dr(1,4) = 1.;
 dr(2,5) = 1.;
 dr(3,6) = 1.;
 dr(4,7) = - pr(7)/sqrt(pr(4)*pr(4)+pr(5)*pr(5)+pr(6)*pr(6)+pr(7)*pr(7));
 
 return pair<AlgebraicMatrix,AlgebraicVector>(dr,pr);
}

pair< AlgebraicMatrix, AlgebraicVector > FourMomentumKinematicConstraint::derivative

(

const AlgebraicVector &

exPoint

)

const [virtual]

Implements KinematicConstraint.

Definition at line 50 of file FourMomentumKinematicConstraint.cc.

References funct::sqrt().

{
 if(exPoint.num_row() ==0) throw VertexException("FourMomentumKinematicConstraint::value requested for zero Linearization point");

//security check for extended cartesian parametrization 
 int inSize = exPoint.num_row(); 
 if((inSize%7) !=0) throw VertexException("FourMomentumKinematicConstraint::linearization point has a wrong dimension");
 int nStates = inSize/7;
 if(nStates != 1) throw VertexException("FourMomentumKinematicConstraint::Multi particle refit is not supported in this version");
 AlgebraicVector pr = exPoint;
 AlgebraicMatrix dr(4,7,0);

 dr(1,4) = 1.;
 dr(2,5) = 1.;
 dr(3,6) = 1.;
 dr(4,7) = pr(7)/ sqrt(pr(4)*pr(4)+pr(5)*pr(5)+pr(6)*pr(6)+pr(7)*pr(7));
  
 return pair<AlgebraicMatrix,AlgebraicVector>(dr,pr);
}

AlgebraicVector FourMomentumKinematicConstraint::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 102 of file FourMomentumKinematicConstraint.cc.

References dd, and res.

{
 if(nStates == 0) throw VertexException("FourMomentumKinematicConstraint::Empty vector of particles passed");
 if(nStates != 1) throw VertexException("FourMomentumKinematicConstraint::Multi particle refit is not supported in this version");
 AlgebraicVector res = dd; 
 return res;
}

int FourMomentumKinematicConstraint::numberOfEquations

(

)

const [virtual]

Returns number of constraint equations used for fitting.

Method is relevant for proper NDF calculations.

Implements KinematicConstraint.

Definition at line 110 of file FourMomentumKinematicConstraint.cc.

{return 4;}

pair< AlgebraicVector, AlgebraicVector > FourMomentumKinematicConstraint::value

(

const vector< RefCountedKinematicParticle >

par

)

const [virtual]

Methods making value and derivative matrix using current state parameters as expansion 7-point.

Constraint can be made equaly for single and multiple states

Implements KinematicConstraint.

Definition at line 70 of file FourMomentumKinematicConstraint.cc.

References mm, and funct::sqrt().

{
 int nStates = par.size();
 if(nStates == 0) throw VertexException("FourMomentumKinematicConstraint::Empty vector of particles passed");
 if(nStates != 1) throw VertexException("FourMomentumKinematicConstraint::Multi particle refit is not supported in this version");
 AlgebraicVector pr = asHepVector<7>(par.front()->currentState().kinematicParameters().vector());
 AlgebraicVector vl(4,0);
 
 vl(1) = pr(4) - mm(1);
 vl(2) = pr(5) - mm(2);
 vl(3) = pr(6) - mm(3);
 vl(7) = sqrt(pr(4)*pr(4)+pr(5)*pr(5)+pr(6)*pr(6)+pr(7)*pr(7)) - mm(4);
 
 return pair<AlgebraicVector,AlgebraicVector>(vl,pr);
}

pair< AlgebraicVector, AlgebraicVector > FourMomentumKinematicConstraint::value

(

const AlgebraicVector &

exPoint

)

const [virtual]

Vector of values and matrix of derivatives calculated at given 7*NumberOfStates expansion point.

Implements KinematicConstraint.

Definition at line 31 of file FourMomentumKinematicConstraint.cc.

References mm, and funct::sqrt().

{
 if(exPoint.num_row() ==0 ) throw VertexException("FourMomentumKinematicConstraint::value requested for zero Linearization point");

//security check for extended cartesian parametrization 
 int inSize = exPoint.num_row(); 
 if((inSize%7) !=0) throw VertexException("FourMomentumKinematicConstraint::linearization point has a wrong dimension");
 int nStates = inSize/7;
 if(nStates != 1) throw VertexException("FourMomentumKinematicConstraint::Multi particle refit is not supported in this version");
 AlgebraicVector pr = exPoint;
 AlgebraicVector vl(4,0);
 vl(1) += (pr(4) - mm(1));
 vl(2) += (pr(5) - mm(2));
 vl(3) += (pr(6) - mm(3));
 vl(7) += (sqrt(pr(4)*pr(4)+pr(5)*pr(5)+pr(6)*pr(6)+pr(7)*pr(7)) - mm(4));
 
 return pair<AlgebraicVector,AlgebraicVector>(vl,pr);
}

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Member Data Documentation

AlgebraicVector FourMomentumKinematicConstraint::dd [private]

Definition at line 62 of file FourMomentumKinematicConstraint.h.

Referenced by deviations(), and FourMomentumKinematicConstraint().

AlgebraicVector FourMomentumKinematicConstraint::mm [private]

Definition at line 61 of file FourMomentumKinematicConstraint.h.

Referenced by FourMomentumKinematicConstraint(), and value().

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

• RecoVertex/KinematicFit/interface/FourMomentumKinematicConstraint.h
• RecoVertex/KinematicFit/src/FourMomentumKinematicConstraint.cc

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