SegmentInPhi0CurvBox.h

/**************************************************************************
 * BASF2 (Belle Analysis Framework 2)                                     *
 * Copyright(C) 2015 - Belle II Collaboration                             *
 *                                                                        *
 * Author: The Belle II Collaboration                                     *
 * Contributors: Oliver Frost                                             *
 *                                                                        *
 * This software is provided "as is" without any warranty.                *
 **************************************************************************/
#pragma once
 
#include <tracking/trackFindingCDC/eventdata/segments/CDCSegment2D.h>
#include <tracking/trackFindingCDC/eventdata/trajectories/CDCTrajectory2D.h>
#include <tracking/trackFindingCDC/hough/phi0_curv/Phi0CurvBox.h>
#include <tracking/trackFindingCDC/geometry/Vector2D.h>
 
namespace Belle2 {
  namespace TrackFindingCDC {
 
    class SegmentInPhi0CurvBox {
 
      Weight operator()(const CDCSegment2D* segment,
                        const Phi0CurvBox* phi0CurvBox)
      {
        if (segment->empty()) return NAN;
        const CDCTrajectory2D& trajectory2D = segment->getTrajectory2D();
        Weight weight = operator()(&trajectory2D, phi0CurvBox);
        return weight * segment->size();
      }
 
      Weight operator()(const CDCTrajectory2D* trajectory2D,
                        const Phi0CurvBox* phi0CurvBox)
      {
        double curvature = trajectory2D->getCurvature();
        const Vector2D& phi0Vec = trajectory2D->getStartUnitMom2D();
 
        bool in = isPhi0CurvPointIn(phi0Vec, curvature, phi0CurvBox);
        return in ? 1 : NAN;
      }
 
 
      Weight operator()(const CDCFacet* facet,
                        const Phi0CurvBox* phi0CurvBox)
      {
        const ParameterLine2D& line = facet->getStartToEndLine();
 
        const Vector2D pos2D = facet->getMiddleRecoPos2D();
        const Vector2D phiVec = line.tangential().unit();
 
        // Calculate the curvature and phi0 of the circle through the origin
        // that touches the position pos2D under the angle phiVec.
        double curvature = 2 * pos2D.cross(phiVec) / pos2D.normSquared();
        Vector2D phi0Vec = phiVec.flippedOver(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 Vector2D& phi0Vec,
                             const double curvature,
                             const Phi0CurvBox* phi0CurvBox)
      {
 
        const Vector2D& lowerPhi0Vec = phi0CurvBox->getLowerPhi0Vec();
        const Vector2D& upperPhi0Vec = phi0CurvBox->getUpperPhi0Vec();
 
        // Allow containment to keep the reversal symmetry
        if (phi0CurvBox->isIn<1>(curvature)) {
          return phi0Vec.isBetween(lowerPhi0Vec, upperPhi0Vec);
 
        } else if (phi0CurvBox->isIn<1>(-curvature)) {
          return (-phi0Vec).isBetween(lowerPhi0Vec, upperPhi0Vec);
 
        } else {
          return false;
 
        }
 
      }
    };
 
  }
}