CurvedLine.cxx

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/*
  Copyright (C) 2002-2021 CERN for the benefit of the ATLAS collaboration
*/
 
#include "MdtCalibFitters/CurvedLine.h"
 
#include "AthenaKernel/getMessageSvc.h"
#include "GaudiKernel/MsgStream.h"
#include "MuonCalibMath/BaseFunctionFitter.h"
#include "MuonCalibMath/LegendrePolynomial.h"
 
using namespace MuonCalib;
 
//*****************************************************************************
 
//:::::::::::::::::::::::::
//:: DEFAULT CONSTRUCTOR ::
//:::::::::::::::::::::::::
 
CurvedLine::CurvedLine() {
    // VARIABLES //
 
    std::vector<Amg::Vector3D> points(3);
    std::vector<Amg::Vector3D> errors(3);

    // FILL VARIABLES //
 
    points[0] = Amg::Vector3D(0.0, 0.0, 0.0);
    errors[0] = Amg::Vector3D(1.0, 1.0, 0.0);
    points[1] = Amg::Vector3D(0.0, 0.0, 1.0);
    errors[1] = Amg::Vector3D(1.0, 1.0, 0.0);
    points[2] = Amg::Vector3D(0.0, 0.0, 2.0);
    errors[2] = Amg::Vector3D(1.0, 1.0, 0.0);

    // INITIALIZATION //
 
    init(points, errors);
}
 
//*****************************************************************************
 
//:::::::::::::::::
//:: CONSTRUCTOR ::
//:::::::::::::::::
 
CurvedLine::CurvedLine(std::vector<Amg::Vector3D>& points) {
    // VARIABLES //
 
    std::vector<Amg::Vector3D> errors(points.size(), Amg::Vector3D(1.0, 1.0, 0.0));

    // INITIALIZATION //
 
    init(points, errors);
}
 
//*****************************************************************************
 
//:::::::::::::::::
//:: CONSTRUCTOR ::
//:::::::::::::::::
 
CurvedLine::CurvedLine(std::vector<Amg::Vector3D>& points, std::vector<Amg::Vector3D>& x_and_y_errors) { init(points, x_and_y_errors); }
 
//*****************************************************************************
 
//::::::::::::::::::::::::::::::
//:: METHOD getPointOnLine ::
//::::::::::::::::::::::::::::::
 
Amg::Vector3D CurvedLine::getPointOnLine(const double  loc_z) const {
    // VARIABLES //
 
    double loc_x{0.0}, loc_y{0.0};

    // CALCULATE THE COORDINATES //
 
    for (int k = 0; k < m_coeff_xz.rows(); k++) { 
        loc_x += m_coeff_xz[k] * std::legendre(k, loc_z); 
    }
 
    for (int k = 0; k < m_coeff_yz.rows(); k++) { 
        loc_y += m_coeff_yz[k] * std::legendre(k, loc_z); 
    }

    // RETURN THE REQUESTED POINT //
 
    return Amg::Vector3D(loc_x, loc_y, loc_z);
}
 
//*****************************************************************************
 
//::::::::::::::::::::::::
//:: METHOD getTangent ::
//::::::::::::::::::::::::
 
MTStraightLine CurvedLine::getTangent(const double  loc_z) const {
    // VARIABLES //
 
    Amg::Vector3D null_vec(0.0, 0.0, 0.0);               // auxiliary 0 vector
    Amg::Vector3D point_1(getPointOnLine(loc_z));        // first point on the curved
                                                         // line
    Amg::Vector3D point_2(getPointOnLine(loc_z + 1.0));  // second point on the
                                                         // curved line

    // RETURN THE TANGENT //
 
    return MTStraightLine(point_1, point_2 - point_1, null_vec, null_vec);
}
 
//*****************************************************************************
 
//:::::::::::::::::
//:: METHOD init ::
//:::::::::::::::::
 
void CurvedLine::init(std::vector<Amg::Vector3D>& points, std::vector<Amg::Vector3D>& x_and_y_errors) {
    // CHECK THE NUMBER OF POINTS //
 
    if (points.size() < 3) {
        MsgStream log(Athena::getMessageSvc(), "CurvedLine");
        log << MSG::ERROR << "Class CurvedLine, method init: Not enough points given, must be at least 3 points!" << endmsg;
    }

    // VARIABLES //
 
    BaseFunctionFitter fitter;
    LegendrePolynomial legendre;                            // Legendre polynomial needed by the base
                                                            // function fitter
    std::vector<SamplePoint> sample_points(points.size());  // sample points needed
                                                            // by the base function
                                                            // fitter
                                                            // FILL THE VARIABLES AND PERFORM THE FITS //
 
    // xz plane //
    for (unsigned int k = 0; k < points.size(); k++) {
        sample_points[k].set_x1(points[k].z());
        sample_points[k].set_x2(points[k].x());
        sample_points[k].set_error(x_and_y_errors[k].x());
    }
    fitter.set_number_of_coefficients(2);
    fitter.fit_parameters(sample_points, 1, sample_points.size(), legendre);
    m_coeff_xz = fitter.coefficients();
 
    // yz plane //
    for (unsigned int k = 0; k < points.size(); k++) {
        sample_points[k].set_x1(points[k].z());
        sample_points[k].set_x2(points[k].y());
        sample_points[k].set_error(x_and_y_errors[k].y());
    }
    fitter.set_number_of_coefficients(3);
    fitter.fit_parameters(sample_points, 1, sample_points.size(), legendre);
    m_coeff_yz = fitter.coefficients();
 
}
void CurvedLine::setChi2(double chi2) { m_chi2 = std::isnan(chi2) ? -1 : chi2; }
double CurvedLine::chi2() const { return m_chi2; }
void CurvedLine::setNumberOfTrackHits(unsigned int n_hits) { m_numTrkHits = n_hits; }
unsigned int CurvedLine::numberOfTrackHits() const { return m_numTrkHits; }
 
double CurvedLine::chi2PerDegreesOfFreedom() const { return m_chi2 / (m_numTrkHits > 2 ? m_numTrkHits - 3 : 0.01); }
 
void CurvedLine::setUsedHits(const MdtHitVec& hits) { m_used_hits = hits; }
const CurvedLine::MdtHitVec& CurvedLine::trackHits() const { return m_used_hits; }