MuonHoughMathUtils.h

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/*
  Copyright (C) 2002-2023 CERN for the benefit of the ATLAS collaboration
*/
 
#ifndef MUONHOUGHPATTERNEVENT_MUONHOUGHMATHUTILS_H
#define MUONHOUGHPATTERNEVENT_MUONHOUGHMATHUTILS_H
 
#include <cmath>
#include <string>
#include <vector>
 
#include "GeoPrimitives/GeoPrimitives.h"
#include "MuonHoughPatternEvent/MuonHoughHit.h"
 
namespace MuonHough {
    constexpr double two_Pi = 2 * M_PI;
    constexpr double degree_rad_conversion_factor = M_PI / 180.;
    constexpr double rad_degree_conversion_factor = 180. / M_PI;
 
    // Geometry for curved Hough extrapolation
    constexpr double tan_barrel = 11430. / 14000.;
    constexpr double radius_cylinder = 4000.;
    constexpr double z_cylinder = 6000.;
    constexpr double z_end = 15000.;
    constexpr double z_magnetic_range = z_end - z_cylinder;
    constexpr double z_magnetic_range_squared = z_end * z_end - z_cylinder * z_cylinder;
}  // namespace MuonHough
 
class MuonHoughMathUtils {
public:
    MuonHoughMathUtils();
    virtual ~MuonHoughMathUtils() = default;
 
    static int sgn(double d);
    static int step(double d, double x0 = 0);
 
    static double signedDistanceToLine(double x0, double y0, double r0, double phi);
    static double distanceToLine(double x0, double y0, double r0, double phi);
    static double incrementTillAbove0(double x, double inc, double zero = 0);
    static double angleFrom0To360(double angle);
    static double angleFrom0To180(double angle);
    static double angleFrom0ToPi(double angle);
    static double angleFromMinusPiToPi(double angle);
    double angleFromRadialToGrad(double angle) const;
    double angleFromGradToRadial(double angle) const;
 
    static std::string intToString(int i);
 
    static double distanceToLine2D(double x0, double y0, double r, double phi) ;
    static double distanceToLine3D(const Amg::Vector3D& point, const Amg::Vector3D& l_trans, double phi, double theta);
 
    static double distanceOfLineToOrigin2D(double a, double b);
    static double signedDistanceOfLineToOrigin2D(double x, double y, double phi);
 
    static double thetaForCurvedHit(double invcurvature, MuonHoughHit* hit);
    static void thetasForCurvedHit(double ratio, MuonHoughHit* hit, double& theta1, double& theta2);
    static double signedDistanceCurvedToHit(double z0, double theta, double invcurvature, const Amg::Vector3D& hit);
 
    static void extrapolateCurvedRoad(const Amg::Vector3D& roadpos, const Amg::Vector3D& roadmom, const Amg::Vector3D& pos,
                                      Amg::Vector3D& roadpose, Amg::Vector3D& roaddire);
 
    static Amg::Vector3D shortestPointOfLineToOrigin3D(const Amg::Vector3D& vec, double phi, double theta);
 
    static Amg::Vector3D shortestPointOfLineToOrigin(const Amg::Vector3D& vec, double phi, double theta);
 
    static bool lineThroughCylinder(const Amg::Vector3D& vec, double phi, double theta, double r_0, double z_0);
 
};
 
inline double MuonHoughMathUtils::angleFromRadialToGrad(double angle) const {
    return (angle / MuonHough::degree_rad_conversion_factor);
}  // angle in radial
inline double MuonHoughMathUtils::angleFromGradToRadial(double angle) const {
    return (angle * MuonHough::degree_rad_conversion_factor);
}  // angle in grad
 
#endif  // MUONHOUGHPATTERNEVENT_MUONHOUGHMATHUTILS_H