#include <KinematicConstrainedVertexUpdator.h>

Public Member Functions
	KinematicConstrainedVertexUpdator ()

std::pair< std::pair< std::vector< KinematicState >, AlgebraicMatrix >, RefCountedKinematicVertex >	update (const AlgebraicVector &inState, const AlgebraicMatrix &inCov, const std::vector< KinematicState > &lStates, const GlobalPoint &lPoint, MultiTrackKinematicConstraint *cs) const

	~KinematicConstrainedVertexUpdator ()

Private Attributes
VertexKinematicConstraint *	vConstraint

KinematicVertexFactory *	vFactory

Detailed Description

Class caching the math part for KinematicConstrainedVertexFitter

Definition at line 13 of file KinematicConstrainedVertexUpdator.h.

Constructor & Destructor Documentation

◆ KinematicConstrainedVertexUpdator()

KinematicConstrainedVertexUpdator::KinematicConstrainedVertexUpdator ( )

Default constructor and destructor

Definition at line 5 of file KinematicConstrainedVertexUpdator.cc.

                                                                      {
   vFactory = new KinematicVertexFactory();
   vConstraint = new VertexKinematicConstraint();
 }

References vConstraint, and vFactory.

◆ ~KinematicConstrainedVertexUpdator()

KinematicConstrainedVertexUpdator::~KinematicConstrainedVertexUpdator ( )

Definition at line 10 of file KinematicConstrainedVertexUpdator.cc.

                                                                       {
   delete vFactory;
   delete vConstraint;
 }

References vConstraint, and vFactory.

Member Function Documentation

◆ update()

std::pair< std::pair< std::vector< KinematicState >, AlgebraicMatrix >, RefCountedKinematicVertex > KinematicConstrainedVertexUpdator::update	(	const AlgebraicVector &	inState,
		const AlgebraicMatrix &	inCov,
		const std::vector< KinematicState > &	lStates,
		const GlobalPoint &	lPoint,
		MultiTrackKinematicConstraint *	cs
	)		const

Method updating the states. Takes a vector of full parameters: (x,y,z,particle_1,...,particle_n), corresponding linearization point: vector of states and GlobalPoint, and constraint to be applied during the vertex fit. Returns refitted vector of 7n+3 parameters and corresponding covariance matrix, where n - number of tracks.

Definition at line 16 of file KinematicConstrainedVertexUpdator.cc.

                                                                                    {
   const MagneticField* field = lStates.front().magneticField();
   AlgebraicMatrix d_matrix = vConstraint->parametersDerivative(lStates, lPoint);
   AlgebraicMatrix e_matrix = vConstraint->positionDerivative(lStates, lPoint);
   AlgebraicVector val_s = vConstraint->value(lStates, lPoint);
   int vSize = lStates.size();
  
   //delta alpha
   AlgebraicVector d_a(7 * vSize + 3);
   d_a(1) = lPoint.x();
   d_a(2) = lPoint.y();
   d_a(3) = lPoint.z();
  
   int cst = 0;
   for (std::vector<KinematicState>::const_iterator i = lStates.begin(); i != lStates.end(); i++) {
     AlgebraicVector lst_par = asHepVector<7>(i->kinematicParameters().vector());
     for (int j = 1; j < lst_par.num_row() + 1; j++) {
       d_a(3 + 7 * cst + j) = lst_par(j);
     }
     cst++;
   }
  
   AlgebraicVector delta_alpha = inPar - d_a;
  
   // cout<<"delta_alpha"<<delta_alpha<<endl;
   //resulting matrix of derivatives and vector of values.
   //their size  depends of number of tracks to analyze and number of
   //additional constraints to apply
   AlgebraicMatrix g;
   AlgebraicVector val;
   if (cs == nullptr) {
     //unconstrained vertex fitter case
     g = AlgebraicMatrix(2 * vSize, 7 * vSize + 3, 0);
     val = AlgebraicVector(2 * vSize);
  
     //filling the derivative matrix
     g.sub(1, 1, e_matrix);
     g.sub(1, 4, d_matrix);
  
     //filling the vector of values
     val = val_s;
   } else {
     //constrained vertex fitter case
     int n_eq = cs->numberOfEquations();
     g = AlgebraicMatrix(n_eq + 2 * vSize, 7 * vSize + 3, 0);
     val = AlgebraicVector(n_eq + 2 * vSize);
     AlgebraicMatrix n_x = cs->positionDerivative(lStates, lPoint);
     AlgebraicMatrix n_alpha = cs->parametersDerivative(lStates, lPoint);
     AlgebraicVector c_val = cs->value(lStates, lPoint);
  
     //filling the derivative matrix
     //   cout<<"n_x:"<<n_x<<endl;
     //   cout<<"n_alpha"<<n_alpha<<endl;
  
     g.sub(1, 1, n_x);
     g.sub(1, 4, n_alpha);
     g.sub(n_eq + 1, 1, e_matrix);
     g.sub(n_eq + 1, 4, d_matrix);
  
     //filling the vector of values
     for (int i = 1; i < n_eq + 1; i++) {
       val(i) = c_val(i);
     }
     for (int i = 1; i < (2 * vSize + 1); i++) {
       val(i + n_eq) = val_s(i);
     }
   }
  
   //check for NaN
   for (int i = 1; i <= val.num_row(); ++i) {
     if (edm::isNotFinite(val(i))) {
       LogDebug("KinematicConstrainedVertexUpdator") << "catched NaN.\n";
       return std::pair<std::pair<std::vector<KinematicState>, AlgebraicMatrix>, RefCountedKinematicVertex>(
           std::pair<std::vector<KinematicState>, AlgebraicMatrix>(std::vector<KinematicState>(), AlgebraicMatrix(1, 0)),
           RefCountedKinematicVertex());
     }
   }
  
   //debug feature
   AlgebraicSymMatrix in_cov_sym(7 * vSize + 3, 0);
  
   for (int i = 1; i < 7 * vSize + 4; ++i) {
     for (int j = 1; j < 7 * vSize + 4; ++j) {
       if (i <= j)
         in_cov_sym(i, j) = inCov(i, j);
     }
   }
  
   //debug code
   AlgebraicSymMatrix v_g_sym = in_cov_sym.similarity(g);
  
   int ifl1 = 0;
   v_g_sym.invert(ifl1);
   if (ifl1 != 0) {
     LogDebug("KinematicConstrainedVertexFitter") << "Fit failed: unable to invert SYM gain matrix\n";
     return std::pair<std::pair<std::vector<KinematicState>, AlgebraicMatrix>, RefCountedKinematicVertex>(
         std::pair<std::vector<KinematicState>, AlgebraicMatrix>(std::vector<KinematicState>(), AlgebraicMatrix(1, 0)),
         RefCountedKinematicVertex());
   }
  
   // delta alpha is now valid!
   //full math case now!
   AlgebraicVector lambda = v_g_sym * (g * delta_alpha + val);
  
   //final parameters
   AlgebraicVector finPar = inPar - in_cov_sym * g.T() * lambda;
  
   //covariance matrix business:
   AlgebraicMatrix mFactor = in_cov_sym * (v_g_sym.similarityT(g)) * in_cov_sym;
  
   //refitted covariance
   AlgebraicMatrix rCov = in_cov_sym - mFactor;
  
   //symmetric covariance:
   AlgebraicSymMatrix r_cov_sym(7 * vSize + 3, 0);
   for (int i = 1; i < 7 * vSize + 4; ++i) {
     for (int j = 1; j < 7 * vSize + 4; ++j) {
       if (i <= j)
         r_cov_sym(i, j) = rCov(i, j);
     }
   }
  
   AlgebraicSymMatrix pCov = r_cov_sym.sub(1, 3);
  
   // chi2
   AlgebraicVector chi = lambda.T() * (g * delta_alpha + val);
  
   //this is ndf without significant prior
   //vertex so -3 factor exists here
   float ndf = 2 * vSize - 3;
   if (cs != nullptr) {
     ndf += cs->numberOfEquations();
   }
  
   //making resulting vertex
   GlobalPoint vPos(finPar(1), finPar(2), finPar(3));
   VertexState st(vPos, GlobalError(asSMatrix<3>(pCov)));
   RefCountedKinematicVertex rVtx = vFactory->vertex(st, chi(1), ndf);
  
   //making refitted states of Kinematic Particles
   int i_int = 0;
   std::vector<KinematicState> ns;
   for (std::vector<KinematicState>::const_iterator i_st = lStates.begin(); i_st != lStates.end(); i_st++) {
     AlgebraicVector7 newPar;
     for (int i = 0; i < 7; i++) {
       newPar(i) = finPar(4 + i_int * 7 + i);
     }
  
     AlgebraicSymMatrix nCovariance = r_cov_sym.sub(4 + i_int * 7, 10 + i_int * 7);
     TrackCharge chl = i_st->particleCharge();
     KinematicParameters nrPar(newPar);
     KinematicParametersError nrEr(asSMatrix<7>(nCovariance));
     KinematicState newState(nrPar, nrEr, chl, field);
     ns.push_back(newState);
     i_int++;
   }
   std::pair<std::vector<KinematicState>, AlgebraicMatrix> ns_m(ns, rCov);
   return std::pair<std::pair<std::vector<KinematicState>, AlgebraicMatrix>, RefCountedKinematicVertex>(ns_m, rVtx);
 }