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1 // 1 //
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24 // ******************************************* 24 // ********************************************************************
25 // 25 //
26 // 26 //
>> 27 // $Id: G4RandomTools.hh,v 1.2 2008/11/07 17:54:21 gum Exp $
>> 28 // GEANT4 tag $Name: geant4-09-03-patch-01 $
27 // 29 //
28 // << 30 //
29 // ------------------------------------------- 31 // ---------------------------------------------------------------------------
30 // GEANT 4 class header file << 32 // GEANT 4 class header file
31 // ------------------------------------------- 33 // ---------------------------------------------------------------------------
32 // Class description: 34 // Class description:
33 // 35 //
34 // Utility functions << 36 // Utility functions
35 37
36 // History: 38 // History:
37 // 39 //
38 // 24.08.17 - E.Tcherniaev, added G4RandomRadi <<
39 // G4RandomPointOnEll <<
40 // 07.11.08 - P.Gumplinger, based on implement 40 // 07.11.08 - P.Gumplinger, based on implementation in G4OpBoundaryProcess
41 // 41 //
42 // ------------------------------------------- 42 // ---------------------------------------------------------------------------
43 43
44 #ifndef G4RANDOMTOOLS_HH 44 #ifndef G4RANDOMTOOLS_HH
45 #define G4RANDOMTOOLS_HH 45 #define G4RANDOMTOOLS_HH
46 46
47 #include <CLHEP/Units/PhysicalConstants.h> <<
48 <<
49 #include "G4RandomDirection.hh" <<
50 #include "G4ThreeVector.hh" <<
51 #include "G4TwoVector.hh" <<
52 #include "Randomize.hh" <<
53 #include "globals.hh" 47 #include "globals.hh"
>> 48 #include "Randomize.hh"
>> 49 #include "G4RandomDirection.hh"
54 50
55 // ------------------------------------------- 51 // ---------------------------------------------------------------------------
56 // Returns a random lambertian unit vector (re << 52 // Returns a random lambertian unit vector
57 // 53 //
58 inline G4ThreeVector G4LambertianRand(const G4 54 inline G4ThreeVector G4LambertianRand(const G4ThreeVector& normal)
59 { 55 {
60 G4ThreeVector vect; 56 G4ThreeVector vect;
61 G4double ndotv; 57 G4double ndotv;
62 G4int count = 0; <<
63 const G4int max_trials = 1024; <<
64 58
65 do 59 do
66 { 60 {
67 ++count; << 61 vect = G4RandomDirection();
68 vect = G4RandomDirection(); <<
69 ndotv = normal * vect; 62 ndotv = normal * vect;
70 63
71 if(ndotv < 0.0) << 64 if (ndotv < 0.0)
72 { 65 {
73 vect = -vect; << 66 vect = -vect;
74 ndotv = -ndotv; 67 ndotv = -ndotv;
75 } 68 }
76 69
77 } while(!(G4UniformRand() < ndotv) && (count << 70 } while (!(G4UniformRand() < ndotv));
78 71
79 return vect; 72 return vect;
80 } 73 }
81 74
82 // ------------------------------------------- 75 // ---------------------------------------------------------------------------
83 // Chooses a random vector within a plane give 76 // Chooses a random vector within a plane given by the unit normal
84 // 77 //
85 inline G4ThreeVector G4PlaneVectorRand(const G 78 inline G4ThreeVector G4PlaneVectorRand(const G4ThreeVector& normal)
86 { 79 {
87 G4ThreeVector vec1 = normal.orthogonal(); 80 G4ThreeVector vec1 = normal.orthogonal();
88 G4ThreeVector vec2 = vec1.cross(normal); 81 G4ThreeVector vec2 = vec1.cross(normal);
89 82
90 G4double phi = CLHEP::twopi * G4UniformRa << 83 G4double phi = twopi*G4UniformRand();
91 G4double cosphi = std::cos(phi); 84 G4double cosphi = std::cos(phi);
92 G4double sinphi = std::sin(phi); 85 G4double sinphi = std::sin(phi);
93 86
94 return cosphi * vec1 + sinphi * vec2; 87 return cosphi * vec1 + sinphi * vec2;
95 } 88 }
96 89
97 // ------------------------------------------- << 90 #endif /* G4RANDOMTOOLS_HH */
98 // Returns a random radius in annular ring <<
99 // <<
100 inline G4double G4RandomRadiusInRing(G4double <<
101 { <<
102 if(rmin == rmax) <<
103 { <<
104 return rmin; <<
105 } <<
106 G4double k = G4UniformRand(); <<
107 return (rmin <= 0) ? rmax * std::sqrt(k) <<
108 : std::sqrt(k * rmax * rm <<
109 } <<
110 <<
111 // ------------------------------------------- <<
112 // Returns a random point in ellipse (x/a)^2 + <<
113 // (rejection sampling) <<
114 // <<
115 inline G4TwoVector G4RandomPointInEllipse(G4do <<
116 { <<
117 G4double aa = (a * a == 0) ? 0 : 1 / (a * a) <<
118 G4double bb = (b * b == 0) ? 0 : 1 / (b * b) <<
119 for(G4int i = 0; i < 1000; ++i) <<
120 { <<
121 G4double x = a * (2 * G4UniformRand() - 1) <<
122 G4double y = b * (2 * G4UniformRand() - 1) <<
123 if(x * x * aa + y * y * bb <= 1) <<
124 return G4TwoVector(x, y); <<
125 } <<
126 return G4TwoVector(0, 0); <<
127 } <<
128 <<
129 // ------------------------------------------- <<
130 // Returns a random point on ellipse (x/a)^2 + <<
131 // (rejection sampling) <<
132 // <<
133 inline G4TwoVector G4RandomPointOnEllipse(G4do <<
134 { <<
135 G4double A = std::abs(a); <<
136 G4double B = std::abs(b); <<
137 G4double mu_max = std::max(A, B); <<
138 <<
139 G4double x, y; <<
140 for(G4int i = 0; i < 1000; ++i) <<
141 { <<
142 G4double phi = CLHEP::twopi * G4UniformRan <<
143 x = std::cos(phi); <<
144 y = std::sin(phi); <<
145 G4double mu = std::sqrt((B * x) * (B * x) <<
146 if(mu_max * G4UniformRand() <= mu) <<
147 break; <<
148 } <<
149 return G4TwoVector(A * x, B * y); <<
150 } <<
151 <<
152 // ------------------------------------------- <<
153 // Returns a random point on ellipsoid (x/a)^2 <<
154 // (rejection sampling) <<
155 // <<
156 inline G4ThreeVector G4RandomPointOnEllipsoid( <<
157 <<
158 { <<
159 G4double A = std::abs(a); <<
160 G4double B = std::abs(b); <<
161 G4double C = std::abs(c); <<
162 G4double mu_max = std::max(std::max(A * B, A <<
163 <<
164 G4ThreeVector p; <<
165 for(G4int i = 0; i < 1000; ++i) <<
166 { <<
167 p = G4RandomDirection(); <<
168 G4double xbc = p.x() * B * C; <<
169 G4double yac = p.y() * A * C; <<
170 G4double zab = p.z() * A * B; <<
171 G4double mu = std::sqrt(xbc * xbc + yac * <<
172 if(mu_max * G4UniformRand() <= mu) <<
173 break; <<
174 } <<
175 return G4ThreeVector(A * p.x(), B * p.y(), C <<
176 } <<
177 <<
178 #endif /* G4RANDOMTOOLS_HH */ <<
179 91