Geant4_10
G4INCLIntersection.hh
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25 //
26 // INCL++ intra-nuclear cascade model
27 // Pekka Kaitaniemi, CEA and Helsinki Institute of Physics
28 // Davide Mancusi, CEA
29 // Alain Boudard, CEA
30 // Sylvie Leray, CEA
31 // Joseph Cugnon, University of Liege
32 //
33 #define INCLXX_IN_GEANT4_MODE 1
34 
35 #include "globals.hh"
36 
44 #ifndef G4INCLINTERSECTION_HH
45 #define G4INCLINTERSECTION_HH 1
46 
47 #include "G4INCLThreeVector.hh"
48 #include <utility>
49 
50 namespace G4INCL {
51 
57  struct Intersection {
58  Intersection(const G4bool e, const G4double t, const ThreeVector &p) :
59  exists(e), time(t), position(p) {}
63  };
64 
65  namespace IntersectionFactory {
66 
99  std::pair<Intersection,Intersection> getTrajectoryIntersections(const ThreeVector &x0, const ThreeVector &p, const G4double r);
100 
101  namespace {
102 
103  Intersection getTrajectoryIntersection(const ThreeVector &x0, const ThreeVector &v, const G4double r, const G4bool earliest) {
104  const G4double scalarVelocity = v.mag();
105  ThreeVector velocityUnitVector = v / scalarVelocity;
106 
107  ThreeVector positionTransverse = x0 - velocityUnitVector * x0.dot(velocityUnitVector);
108  const G4double impactParameter = positionTransverse.mag();
109 
110  const G4double r2 = r*r;
111  G4double distanceZ2 = r2 - impactParameter * impactParameter;
112  if(distanceZ2 < 0.0)
113  return Intersection(false, 0.0, ThreeVector());
114 
115  const G4double distanceZ = std::sqrt(distanceZ2);
116  const ThreeVector position = positionTransverse + velocityUnitVector * (earliest ? -distanceZ : distanceZ);
117  const G4double time = (position-x0).dot(velocityUnitVector)/scalarVelocity;
118  return Intersection(true, time, position);
119  }
120 
121  }
122 
124  return getTrajectoryIntersection(x0, p, r, true);
125  }
126 
128  return getTrajectoryIntersection(x0, p, r, false);
129  }
130 
131  inline std::pair<Intersection,Intersection> getTrajectoryIntersections(const ThreeVector &x0, const ThreeVector &p, const G4double r) {
132  return std::make_pair(
133  getTrajectoryIntersection(x0, p, r, true),
134  getTrajectoryIntersection(x0, p, r, false)
135  );
136  }
137  }
138 
139 }
140 
141 #endif /* G4INCLINTERSECTION_HH */
G4double dot(const ThreeVector &v) const
const char * p
Definition: xmltok.h:285
Intersection getLaterTrajectoryIntersection(const ThreeVector &x0, const ThreeVector &p, const G4double r)
Compute the second intersection of a straight particle trajectory with a sphere.
bool G4bool
Definition: G4Types.hh:79
Intersection getEarlierTrajectoryIntersection(const ThreeVector &x0, const ThreeVector &p, const G4double r)
Compute the first intersection of a straight particle trajectory with a sphere.
std::pair< Intersection, Intersection > getTrajectoryIntersections(const ThreeVector &x0, const ThreeVector &p, const G4double r)
Compute both intersections of a straight particle trajectory with a sphere.
tuple v
Definition: test.py:18
jump r
Definition: plot.C:36
Intersection(const G4bool e, const G4double t, const ThreeVector &p)
Intersection-point structure.
G4double mag() const
double G4double
Definition: G4Types.hh:76