MultiTrackPointingKinematicConstraint Class Reference

#include <MultiTrackPointingKinematicConstraint.h>

Inheritance diagram for MultiTrackPointingKinematicConstraint:

Public Member Functions
virtual MultiTrackPointingKinematicConstraint *	clone () const
	MultiTrackPointingKinematicConstraint (GlobalPoint &ref)
virtual int	numberOfEquations () const
virtual AlgebraicMatrix	parametersDerivative (const std::vector< KinematicState > &states, const GlobalPoint &point) const
virtual AlgebraicMatrix	positionDerivative (const std::vector< KinematicState > &states, const GlobalPoint &point) const
virtual AlgebraicVector	value (const std::vector< KinematicState > &states, const GlobalPoint &point) const
Public Member Functions inherited from MultiTrackKinematicConstraint
	MultiTrackKinematicConstraint ()
virtual	~MultiTrackKinematicConstraint ()

Private Attributes
GlobalPoint	refPoint

Detailed Description

Topological constraint making a momentum vector to point to the given location in space. Example: if b-meson momentum is reconstructed at b-meson decay position (secondary vertex), making reconstructed momentum be in parallel to the link from primary vertex to secondary vertex.

Kirill Prokofiev, March 2004 MultiTrack version including propagation to linearization point: Lars Perchalla, Philip Sauerland, Dec 2009

Definition at line 21 of file MultiTrackPointingKinematicConstraint.h.

Constructor & Destructor Documentation

MultiTrackPointingKinematicConstraint::MultiTrackPointingKinematicConstraint ( GlobalPoint &  ref )

inline

Definition at line 24 of file MultiTrackPointingKinematicConstraint.h.

Referenced by clone().

                                                           :refPoint(ref)
    {}

Member Function Documentation

virtual MultiTrackPointingKinematicConstraint* MultiTrackPointingKinematicConstraint::clone ( void  ) const

inlinevirtual

Implements MultiTrackKinematicConstraint.

Definition at line 53 of file MultiTrackPointingKinematicConstraint.h.

References MultiTrackPointingKinematicConstraint().

    {
        return new MultiTrackPointingKinematicConstraint(*this);
    }

int MultiTrackPointingKinematicConstraint::numberOfEquations ( ) const

virtual

Number of equations per track used for the fit

Implements MultiTrackKinematicConstraint.

Definition at line 114 of file MultiTrackPointingKinematicConstraint.cc.

                                                                  {
    return 2;
}

AlgebraicMatrix MultiTrackPointingKinematicConstraint::parametersDerivative ( const std::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 35 of file MultiTrackPointingKinematicConstraint.cc.

References a, cuy::col, i, makeMuonMisalignmentScenario::matrix, pileupDistInMC::num, funct::pow(), mathSSE::sqrt(), PV3DBase< T, PVType, FrameType >::x(), PV3DBase< T, PVType, FrameType >::y(), and z.

                                                                                                                                                  {
    int num = states.size();
    if(num<2) throw VertexException("MultiTrackPointingKinematicConstraint::parametersDerivative <2 states passed");
    
    //2 equations (for all tracks)
    AlgebraicMatrix  matrix(2,num*7,0);//AlgebraicMatrix starts from 1
    
    double pxSum=0, pySum=0, pzSum=0;
    for(std::vector<KinematicState>::const_iterator i = states.begin(); i != states.end(); i++)
    {
        double a = - i->particleCharge() * i->magneticField()->inInverseGeV(i->globalPosition()).z();
        
        pxSum += i->kinematicParameters()(3) - a*(point.y() - i->kinematicParameters()(1));
        pySum += i->kinematicParameters()(4) + a*(point.x() - i->kinematicParameters()(0));
        pzSum += i->kinematicParameters()(5);
    }

    double pT = sqrt(pow(pxSum,2) + pow(pySum,2));
    double pSum = sqrt(pow(pxSum,2) + pow(pySum,2) + pow(pzSum,2));

    int col=0;
    for(std::vector<KinematicState>::const_iterator i = states.begin(); i != states.end(); i++){
        double a = - i->particleCharge() * i->magneticField()->inInverseGeV(i->globalPosition()).z();

        matrix(1,1+col*7) = a*(1/pT + (-pT + pxSum)/pow(pySum,2));//dH/dx
        matrix(1,2+col*7) = (a - (a*pxSum)/pT)/pySum;//dH/dy
        //dH/dz=0
        matrix(1,4+col*7) = (pT - pxSum)/(pT*pySum);//dH/dpx
        matrix(1,5+col*7) = -(1/pT) + (pT - pxSum)/pow(pySum,2);//dH/dpy        
        //dH/dpz=0
        //dH/dm=0
        matrix(2,1+col*7) = (a*(-pSum + pT)*pySum)/(pSum*pT*pzSum);//dH/dx
        matrix(2,2+col*7) = (a*( pSum - pT)*pxSum)/(pSum*pT*pzSum);//dH/dy
        //dH/dz
        matrix(2,4+col*7) = ((-(1/pSum) + 1/pT)*pxSum)/pzSum;//dH/dpx
        matrix(2,5+col*7) = ((-(1/pSum) + 1/pT)*pySum)/pzSum;//dH/dpy
        matrix(2,6+col*7) = -(1/pSum) + (pSum - pT)/pow(pzSum,2);//dH/dpz
        //dH/dm=0       

        col++;
    }
    
    return matrix;
}

AlgebraicMatrix MultiTrackPointingKinematicConstraint::positionDerivative ( const std::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 80 of file MultiTrackPointingKinematicConstraint.cc.

References a, i, makeMuonMisalignmentScenario::matrix, pileupDistInMC::num, funct::pow(), refPoint, mathSSE::sqrt(), PV3DBase< T, PVType, FrameType >::x(), PV3DBase< T, PVType, FrameType >::y(), z, and PV3DBase< T, PVType, FrameType >::z().

                                                                                                                                                {
    int num = states.size();
    if(num<2) throw VertexException("MultiTrackPointingKinematicConstraint::positionDerivative <2 states passed");
    
    //2 equations (for all tracks)
    AlgebraicMatrix  matrix(2,3,0);
    double dx = point.x() - refPoint.x();
    double dy = point.y() - refPoint.y();
    double dz = point.z() - refPoint.z();
    double dT = sqrt(pow(dx,2) + pow(dy,2));
    double ds = sqrt(pow(dx,2) + pow(dy,2) + pow(dz,2));
    
    double pxSum=0, pySum=0, pzSum=0, aSum = 0;
    for(std::vector<KinematicState>::const_iterator i = states.begin(); i != states.end(); i++){
        double a = - i->particleCharge() * i->magneticField()->inInverseGeV(i->globalPosition()).z();
        aSum += a;
        
        pxSum += i->kinematicParameters()(3) - a*(point.y() - i->kinematicParameters()(1));
        pySum += i->kinematicParameters()(4) + a*(point.x() - i->kinematicParameters()(0));
        pzSum += i->kinematicParameters()(5);
    }
    double pT = sqrt(pow(pxSum,2) + pow(pySum,2));
    double pSum = sqrt(pow(pxSum,2) + pow(pySum,2) + pow(pzSum,2));

    matrix(1,1) = (-1 + dx/dT)/dy - aSum/pT + (aSum*(pT - pxSum))/pow(pySum,2);//dH/dxv
    matrix(1,2) = 1/dT + (-dT + dx)/pow(dy,2) - (aSum*(pT - pxSum))/(pT*pySum);//dH/dyv
    //dH/dzv=0
    matrix(2,1) = ((1/ds - 1/dT)*dx)/dz + (aSum*(pSum - pT)*pySum)/(pSum*pT*pzSum);//dH/dxv
    matrix(2,2) = ((1/ds - 1/dT)*dy)/dz - (aSum*(pSum - pT)*pxSum)/(pSum*pT*pzSum);//dH/dyv
    matrix(2,3) = 1/ds + (-ds + dT)/pow(dz,2);//dH/dzv
    
    return matrix;
}

AlgebraicVector MultiTrackPointingKinematicConstraint::value ( const std::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 4 of file MultiTrackPointingKinematicConstraint.cc.

References a, i, pileupDistInMC::num, funct::pow(), refPoint, mathSSE::sqrt(), PV3DBase< T, PVType, FrameType >::x(), PV3DBase< T, PVType, FrameType >::y(), z, and PV3DBase< T, PVType, FrameType >::z().

                                                                                                                                   {
    int num = states.size();
    if(num<2) throw VertexException("MultiTrackPointingKinematicConstraint::value <2 states passed");

    //2 equations (for all tracks)
    AlgebraicVector  vl(2,0);
    double dx = point.x() - refPoint.x();
    double dy = point.y() - refPoint.y();
    double dz = point.z() - refPoint.z();
    double dT = sqrt(pow(dx,2) + pow(dy,2));
    double ds = sqrt(pow(dx,2) + pow(dy,2) + pow(dz,2));

    double pxSum=0, pySum=0, pzSum=0;
    for(std::vector<KinematicState>::const_iterator i = states.begin(); i != states.end(); i++)
    {
        double a = - i->particleCharge() * i->magneticField()->inInverseGeV(i->globalPosition()).z();

        pxSum += i->kinematicParameters()(3) - a*(point.y() - i->kinematicParameters()(1));
        pySum += i->kinematicParameters()(4) + a*(point.x() - i->kinematicParameters()(0));
        pzSum += i->kinematicParameters()(5);
    }
    
    double pT = sqrt(pow(pxSum,2) + pow(pySum,2));
    double pSum = sqrt(pow(pxSum,2) + pow(pySum,2) + pow(pzSum,2));
    
    vl(1) = (dT - dx)/dy + (pxSum - pT)/pySum;
    vl(2) = (ds - dT)/dz + (pT - pSum)/pzSum;
    
    return vl;
}

Member Data Documentation

GlobalPoint MultiTrackPointingKinematicConstraint::refPoint

private

Definition at line 59 of file MultiTrackPointingKinematicConstraint.h.

Referenced by positionDerivative(), and value().