TrackFitterLinearRegression.h

#ifndef TRACKFITTERLINEARREGRESSION_H
#define TRACKFITTERLINEARREGRESSION_H

#include <marlin/Processor.h>
#include <lcio.h>
#include <string>
#include "TrackFitterBase.h"
#include <EVENT/Track.h>
#include <IMPL/TrackImpl.h>
#include <EVENT/TrackerHit.h>


namespace marlintpc
{
class TrackFitterLinearRegression : public TrackFitterBase
{
public:

        TrackFitterLinearRegression();

        virtual ~TrackFitterLinearRegression() {}

        static TrackFitterBase * getInstance(LCParameters const * parameters);

        virtual std::string getRevision() const;

        virtual unsigned char getFitterType() const;

        virtual IMPL::TrackImpl *fitTrack(EVENT::Track const * seedTrack) const;

protected:
        //helper function to perform the linear regression in the xy-plane
        EVENT::DoubleVec doRegressionXY(EVENT::Track const * seedTrack) const;

        //helper function to perform the linear regression in the sz-plane
        EVENT::DoubleVec doRegressionSZ(EVENT::Track const * seedTrack) const;

        //helper function to calculate the point of closest approach of the track
        EVENT::DoubleVec calculatePCA(EVENT::Track const * seedTrack) const;

        //helper function to calculate the arc length
        double calculateS(EVENT::TrackerHit * aHit, EVENT::DoubleVec pca, EVENT::Track const * seedTrack ) const;

};
} // namespace marlintpc
#endif // TRACKFITTERLINEARREGRESSION_H