ChargeSignificanceTrajectoryFilter.h

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#ifndef ChargeSignificanceTrajectoryFilter_H
#define ChargeSignificanceTrajectoryFilter_H

#include "TrackingTools/TrajectoryFiltering/interface/TrajectoryFilter.h"
#include "TrackingTools/PatternTools/interface/Trajectory.h"
#include "TrackingTools/PatternTools/interface/TempTrajectory.h"

class ChargeSignificanceTrajectoryFilter : public TrajectoryFilter {
public:

  explicit ChargeSignificanceTrajectoryFilter( double qsig):  theChargeSignificance(qsig) {}

  explicit ChargeSignificanceTrajectoryFilter( const edm::ParameterSet & pset):
    theChargeSignificance(pset.getParameter<double>("chargeSignificance")) {}

  virtual bool qualityFilter( const Trajectory& traj) const { return traj.isValid();}
  virtual bool qualityFilter( const TempTrajectory& traj)const { return traj.isValid();}
 
  virtual bool toBeContinued( Trajectory& traj)const { return TBC<Trajectory>(traj);}
  virtual bool toBeContinued( TempTrajectory& traj) const { return TBC<TempTrajectory>(traj);}
  
  virtual std::string name() const {return "ChargeSignificanceTrajectoryFilter";}

protected:

  template <class T> bool TBC(T & traj) const{
    const typename T::DataContainer & tms = traj.measurements();
    // Check flip in q-significance. The loop over all TMs could be 
    // avoided by storing the current significant q in the trajectory
    if ( theChargeSignificance>0. ) {
      int qSig(0);
      // skip first two hits (don't rely on significance of q/p)
      for( typename T::DataContainer::size_type itm=2; itm<tms.size(); ++itm ) {
    TrajectoryStateOnSurface tsos = tms[itm].updatedState();
    if ( !tsos.isValid() )  continue;
    double significance = tsos.localParameters().vector()(0) /
      sqrt(tsos.localError().matrix()(0,0));
    // don't deal with measurements compatible with 0
    if ( fabs(significance)<theChargeSignificance )  continue;
    //
    // if charge not yet defined: store first significant Q
    //
    if ( qSig==0 ) {
      qSig = significance>0 ? 1 : -1;
    }
    //
    // else: invalidate and terminate in case of a change of sign
    //
    else {
      if ( (significance<0.&&qSig>0) || (significance>0.&&qSig<0) ) {
        traj.invalidate();
        return false;
      }
    }
      }
    }
    return true;
  }

  double theChargeSignificance;

};

#endif