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G4UniversalFluctuation.hh
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26 // $Id: G4UniversalFluctuation.hh 101807 2016-11-30 13:42:28Z gunter $
27 //
28 // -------------------------------------------------------------------
29 //
30 // GEANT4 Class header file
31 //
32 //
33 // File name: G4UniversalFluctuation
34 //
35 // Author: V.Ivanchenko make a class with the Laszlo Urban model
36 //
37 // Creation date: 03.01.2002
38 //
39 // Modifications:
40 //
41 // 09-12-02 remove warnings (V.Ivanchenko)
42 // 28-12-02 add method Dispersion (V.Ivanchenko)
43 // 07-02-03 change signature (V.Ivanchenko)
44 // 13-02-03 Add name (V.Ivanchenko)
45 // 16-10-03 Changed interface to Initialisation (V.Ivanchenko)
46 // 07-02-05 define problem = 5.e-3 (mma)
47 //
48 // Class Description:
49 //
50 // Implementation of energy loss fluctuations
51 
52 // -------------------------------------------------------------------
53 //
54 
55 #ifndef G4UniversalFluctuation_h
56 #define G4UniversalFluctuation_h 1
57 
58 
59 #include "G4VEmFluctuationModel.hh"
60 #include "G4ParticleDefinition.hh"
61 #include "G4Poisson.hh"
63 
65 {
66 
67 public:
68 
69  explicit G4UniversalFluctuation(const G4String& nam = "UniFluc");
70 
71  virtual ~G4UniversalFluctuation();
72 
74  const G4DynamicParticle*,
75  G4double,
76  G4double,
77  G4double) override;
78 
79  virtual G4double Dispersion(const G4Material*,
80  const G4DynamicParticle*,
81  G4double,
82  G4double) override;
83 
84  virtual void InitialiseMe(const G4ParticleDefinition*) final;
85 
86  // Initialisation prestep
87  virtual void SetParticleAndCharge(const G4ParticleDefinition*,
88  G4double q2) final;
89 
90 private:
91 
92  inline void AddExcitation(CLHEP::HepRandomEngine* rndm,
93  G4double a, G4double e, G4double& eav,
94  G4double& eloss, G4double& esig2);
95 
96  inline void SampleGauss(CLHEP::HepRandomEngine* rndm,
97  G4double eav, G4double esig2,
98  G4double& eloss);
99 
100  // hide assignment operator
101  G4UniversalFluctuation & operator=(const G4UniversalFluctuation &right) = delete;
103 
104  const G4ParticleDefinition* particle;
105  const G4Material* lastMaterial;
106 
107  G4double particleMass;
108 
109  // Derived quantities
110  G4double m_Inv_particleMass;
111  G4double m_massrate;
112  G4double chargeSquare;
113 
114  // data members to speed up the fluctuation calculation
115  G4double ipotFluct;
116  G4double electronDensity;
117 
118  G4double f1Fluct;
119  G4double f2Fluct;
120  G4double e1Fluct;
121  G4double e2Fluct;
122  G4double e1LogFluct;
123  G4double e2LogFluct;
124  G4double ipotLogFluct;
125  G4double e0;
126  G4double esmall;
127 
128  G4double e1,e2;
129 
130  G4double minNumberInteractionsBohr;
131  G4double minLoss;
132  G4double nmaxCont;
133  G4double rate,fw;
134 
135  G4int sizearray;
136  G4double* rndmarray;
137 
138 };
139 
140 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
141 
142 
143 inline void
144 G4UniversalFluctuation::AddExcitation(CLHEP::HepRandomEngine* rndm,
145  G4double ax, G4double ex, G4double& eav,
146  G4double& eloss, G4double& esig2)
147 {
148  if(ax > nmaxCont) {
149  eav += ax*ex;
150  esig2 += ax*ex*ex;
151  } else if(ax > 0.) {
152  G4double p = G4double(G4Poisson(ax));
153  eloss += p*ex;
154  if(p > 0.) { eloss += (1.-2.*rndm->flat())*ex; }
155  }
156 }
157 
158 inline void
159 G4UniversalFluctuation::SampleGauss(CLHEP::HepRandomEngine* rndm,
160  G4double eav, G4double esig2,
161  G4double& eloss)
162 {
163  G4double x = eav;
164  if(esig2 > 0.0) {
165  G4double sig = std::sqrt(esig2);
166  G4double deltae = std::min(4.*sig, eav);
167  if(deltae < 0.25*sig) {
168  x += (2.*rndm->flat() - 1.)*deltae;
169  } else {
170  do {
171  x = G4RandGauss::shoot(rndm, eav, sig);
172  } while (x < eav-deltae || x > eav+deltae);
173  // Loop checking, 23-Feb-2016, Vladimir Ivanchenko
174  }
175  }
176  eloss += x;
177 }
178 
179 #endif
180 
ThreeVector shoot(const G4int Ap, const G4int Af)
G4long G4Poisson(G4double mean)
Definition: G4Poisson.hh:51
virtual G4double Dispersion(const G4Material *, const G4DynamicParticle *, G4double, G4double) override
std::vector< ExP01TrackerHit * > a
Definition: ExP01Classes.hh:33
virtual G4double SampleFluctuations(const G4MaterialCutsCouple *, const G4DynamicParticle *, G4double, G4double, G4double) override
const char * p
Definition: xmltok.h:285
G4UniversalFluctuation(const G4String &nam="UniFluc")
tuple x
Definition: test.py:50
virtual double flat()=0
int G4int
Definition: G4Types.hh:78
virtual void SetParticleAndCharge(const G4ParticleDefinition *, G4double q2) final
virtual void InitialiseMe(const G4ParticleDefinition *) final
T min(const T t1, const T t2)
brief Return the smallest of the two arguments
double G4double
Definition: G4Types.hh:76