BarrelUtil.h

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#ifndef TkDetLayers_BarrelUtil_h
#define TkDetLayers_BarrelUtil_h

#include "Geometry/CommonDetUnit/interface/GeomDet.h"

#include "TrackingTools/DetLayers/interface/GeometricSearchDet.h"
#include "TrackingTools/DetLayers/interface/MeasurementEstimator.h"
#include "TrackingTools/DetLayers/interface/rangesIntersect.h"
#include "TrackingTools/TrajectoryState/interface/TrajectoryStateOnSurface.h"
#include "DataFormats/GeometryVector/interface/VectorUtil.h"

#pragma GCC visibility push(hidden)
namespace barrelUtil {

  inline float calculatePhiWindow(float Xmax, const GeomDet& det, const TrajectoryStateOnSurface& state) {
    LocalPoint startPoint = state.localPosition();
    LocalVector shift(Xmax, 0., 0.);
    LocalPoint shift1 = startPoint + shift;
    LocalPoint shift2 = startPoint + (-shift);
    //LocalPoint shift2( startPoint); //original code;
    //shift2 -= shift;

    auto phi1 = det.surface().toGlobal(shift1).barePhi();
    auto phi2 = det.surface().toGlobal(shift2).barePhi();
    auto phiStart = state.globalPosition().barePhi();
    auto phiWin = std::min(std::abs(phiStart - phi1), std::abs(phiStart - phi2));

    return phiWin;
  }

  inline float computeWindowSize(const GeomDet* det,
                                 const TrajectoryStateOnSurface& tsos,
                                 const MeasurementEstimator& est) {
    auto xmax = est.maximalLocalDisplacement(tsos, det->surface()).x();
    return calculatePhiWindow(xmax, *det, tsos);
  }

  inline bool overlap(float phi, const GeometricSearchDet& gsdet, float phiWin) {
    // introduce offset (extrapolated point and true propagated point differ by 0.0003 - 0.00033,
    // due to thickness of Rod of 1 cm)
    constexpr float phiOffset = 0.00034;  //...TOBE CHECKED LATER...
    phiWin += phiOffset;

    // detector phi range
    std::pair<float, float> phiRange(phi - phiWin, phi + phiWin);

    return rangesIntersect(phiRange, gsdet.surface().phiSpan(), [](auto x, auto y) { return Geom::phiLess(x, y); });
  }

}  // namespace barrelUtil

#pragma GCC visibility pop
#endif