# Project CMSSW displayed by LXR

File indexing completed on 2023-10-25 10:05:48

```0001 #ifndef RKCurvilinearDistance_H
0002 #define RKCurvilinearDistance_H
0003
0004 #include "DataFormats/GeometryVector/interface/Basic3DVector.h"
0005 #include "FWCore/Utilities/interface/Visibility.h"
0006 #include "RKDistance.h"
0007 #include "RKSmallVector.h"
0008
0009 template <typename T, int N>
0010 class dso_internal RKCurvilinearDistance : public RKDistance<T, N> {
0011 public:
0012   typedef T Scalar;
0013   typedef RKSmallVector<T, N> Vector;
0014
0015   ~RKCurvilinearDistance() override {}
0016
0017   Scalar operator()(const Vector& a, const Vector& b, const Scalar& s) const override {
0018     Basic3DVector<Scalar> amom = momentum(a);
0019     Basic3DVector<Scalar> bmom = momentum(b);
0020
0021     return sqrt(sqr(a(0) - b(0)) + sqr(a(1) - b(1))) + (amom - bmom).mag() / bmom.mag();
0022   }
0023
0024   Basic3DVector<Scalar> momentum(const Vector& v) const {
0025     Scalar k = sqrt(1 + sqr(v(2)) + sqr(v(3)));
0026     Scalar p = std::abs(1 / v(4));
0027     Scalar pz = p / k;
0028     return Basic3DVector<Scalar>(v(2) * pz, v(3) * pz, pz);
0029   }
0030
0031   T sqr(const T& t) const { return t * t; }
0032 };
0033
0034 #endif```