SegmentInPhi0CurvBox.h

/**************************************************************************
 * basf2 (Belle II Analysis Software Framework)                           *
 * Author: The Belle II Collaboration                                     *
 *                                                                        *
 * See git log for contributors and copyright holders.                    *
 * This file is licensed under LGPL-3.0, see LICENSE.md.                  *
 **************************************************************************/
#pragma once
 
#include <tracking/trackingUtilities/eventdata/segments/CDCSegment2D.h>
#include <tracking/trackingUtilities/eventdata/trajectories/CDCTrajectory2D.h>
#include <tracking/trackFindingCDC/hough/phi0_curv/Phi0CurvBox.h>
#include <tracking/trackingUtilities/geometry/VectorUtil.h>
 
#include <Math/Vector2D.h>
 
namespace Belle2 {
  namespace TrackFindingCDC {

    class SegmentInPhi0CurvBox {

      TrackingUtilities::Weight operator()(const TrackingUtilities::CDCSegment2D* segment,
                                           const Phi0CurvBox* phi0CurvBox)
      {
        if (segment->empty()) return NAN;
        const TrackingUtilities::CDCTrajectory2D& trajectory2D = segment->getTrajectory2D();
        TrackingUtilities::Weight weight = operator()(&trajectory2D, phi0CurvBox);
        return weight * segment->size();
      }

      TrackingUtilities::Weight operator()(const TrackingUtilities::CDCTrajectory2D* trajectory2D,
                                           const Phi0CurvBox* phi0CurvBox)
      {
        double curvature = trajectory2D->getCurvature();
        const ROOT::Math::XYVector& phi0Vec = trajectory2D->getStartUnitMom2D();
 
        bool in = isPhi0CurvPointIn(phi0Vec, curvature, phi0CurvBox);
        return in ? 1 : NAN;
      }
 

      TrackingUtilities::Weight operator()(const TrackingUtilities::CDCFacet* facet,
                                           const Phi0CurvBox* phi0CurvBox)
      {
        const ParameterLine2D& line = facet->getStartToEndLine();
 
        const ROOT::Math::XYVector pos2D = facet->getMiddleRecoPos2D();
        const ROOT::Math::XYVector phiVec = VectorUtil::unit(line.tangential());
 
        // Calculate the curvature and phi0 of the circle through the origin
        // that touches the position pos2D under the angle phiVec.
        double curvature = 2 * VectorUtil::Cross(pos2D, phiVec) / pos2D.Mag2();
        ROOT::Math::XYVector phi0Vec = VectorUtil::flippedOver(phiVec, pos2D);
 
        bool in = isPhi0CurvPointIn(phi0Vec, curvature, phi0CurvBox);
        return in ? 1 : NAN;
        // All facets are currently worth the same weight
        // Facets contain three hits but in general contribute only one
        // additional hit due to overlaps with neighboring facets.
        // Hence we stick with 1 as weight here.
      }

      bool isPhi0CurvPointIn(const ROOT::Math::XYVector& phi0Vec,
                             const double curvature,
                             const Phi0CurvBox* phi0CurvBox)
      {
 
        const ROOT::Math::XYVector& lowerPhi0Vec = phi0CurvBox->getLowerPhi0Vec();
        const ROOT::Math::XYVector& upperPhi0Vec = phi0CurvBox->getUpperPhi0Vec();
 
        // Allow containment to keep the reversal symmetry
        if (phi0CurvBox->isIn<1>(curvature)) {
          return VectorUtil::isBetween(phi0Vec, lowerPhi0Vec, upperPhi0Vec);
 
        } else if (phi0CurvBox->isIn<1>(-curvature)) {
          return VectorUtil::isBetween(-phi0Vec, lowerPhi0Vec, upperPhi0Vec);
 
        } else {
          return false;
 
        }
 
      }
    };
 
  }
}