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25 // 25 //
26 // 26 //
>> 27 // $Id: G4RandomTools.hh 105368 2017-07-24 09:44:20Z gcosmo $
27 // 28 //
28 // << 29 //
29 // ------------------------------------------- 30 // ---------------------------------------------------------------------------
30 // GEANT 4 class header file << 31 // GEANT 4 class header file
31 // ------------------------------------------- 32 // ---------------------------------------------------------------------------
32 // Class description: 33 // Class description:
33 // 34 //
34 // Utility functions << 35 // Utility functions
35 36
36 // History: 37 // History:
37 // 38 //
38 // 24.08.17 - E.Tcherniaev, added G4RandomRadi 39 // 24.08.17 - E.Tcherniaev, added G4RandomRadiusInRing, G4RandomPointInEllipse
39 // G4RandomPointOnEll 40 // G4RandomPointOnEllipse, G4RandomPointOnEllipsoid
40 // 07.11.08 - P.Gumplinger, based on implement 41 // 07.11.08 - P.Gumplinger, based on implementation in G4OpBoundaryProcess
41 // 42 //
42 // ------------------------------------------- 43 // ---------------------------------------------------------------------------
43 44
44 #ifndef G4RANDOMTOOLS_HH 45 #ifndef G4RANDOMTOOLS_HH
45 #define G4RANDOMTOOLS_HH 46 #define G4RANDOMTOOLS_HH
46 47
47 #include <CLHEP/Units/PhysicalConstants.h> 48 #include <CLHEP/Units/PhysicalConstants.h>
48 49
49 #include "G4RandomDirection.hh" <<
50 #include "G4ThreeVector.hh" <<
51 #include "G4TwoVector.hh" <<
52 #include "Randomize.hh" <<
53 #include "globals.hh" 50 #include "globals.hh"
>> 51 #include "Randomize.hh"
>> 52 #include "G4TwoVector.hh"
>> 53 #include "G4ThreeVector.hh"
>> 54 #include "G4RandomDirection.hh"
54 55
55 // ------------------------------------------- 56 // ---------------------------------------------------------------------------
56 // Returns a random lambertian unit vector (re 57 // Returns a random lambertian unit vector (rejection sampling)
57 // 58 //
58 inline G4ThreeVector G4LambertianRand(const G4 59 inline G4ThreeVector G4LambertianRand(const G4ThreeVector& normal)
59 { 60 {
60 G4ThreeVector vect; 61 G4ThreeVector vect;
61 G4double ndotv; 62 G4double ndotv;
62 G4int count = 0; << 63 G4int count=0;
63 const G4int max_trials = 1024; 64 const G4int max_trials = 1024;
64 65
65 do 66 do
66 { 67 {
67 ++count; 68 ++count;
68 vect = G4RandomDirection(); << 69 vect = G4RandomDirection();
69 ndotv = normal * vect; 70 ndotv = normal * vect;
70 71
71 if(ndotv < 0.0) << 72 if (ndotv < 0.0)
72 { 73 {
73 vect = -vect; << 74 vect = -vect;
74 ndotv = -ndotv; 75 ndotv = -ndotv;
75 } 76 }
76 77
77 } while(!(G4UniformRand() < ndotv) && (count << 78 } while (!(G4UniformRand() < ndotv) && (count < max_trials));
78 79
79 return vect; 80 return vect;
80 } 81 }
81 82
82 // ------------------------------------------- 83 // ---------------------------------------------------------------------------
83 // Chooses a random vector within a plane give 84 // Chooses a random vector within a plane given by the unit normal
84 // 85 //
85 inline G4ThreeVector G4PlaneVectorRand(const G 86 inline G4ThreeVector G4PlaneVectorRand(const G4ThreeVector& normal)
86 { 87 {
87 G4ThreeVector vec1 = normal.orthogonal(); 88 G4ThreeVector vec1 = normal.orthogonal();
88 G4ThreeVector vec2 = vec1.cross(normal); 89 G4ThreeVector vec2 = vec1.cross(normal);
89 90
90 G4double phi = CLHEP::twopi * G4UniformRa << 91 G4double phi = CLHEP::twopi*G4UniformRand();
91 G4double cosphi = std::cos(phi); 92 G4double cosphi = std::cos(phi);
92 G4double sinphi = std::sin(phi); 93 G4double sinphi = std::sin(phi);
93 94
94 return cosphi * vec1 + sinphi * vec2; 95 return cosphi * vec1 + sinphi * vec2;
95 } 96 }
96 97
97 // ------------------------------------------- 98 // ---------------------------------------------------------------------------
98 // Returns a random radius in annular ring 99 // Returns a random radius in annular ring
99 // 100 //
100 inline G4double G4RandomRadiusInRing(G4double 101 inline G4double G4RandomRadiusInRing(G4double rmin, G4double rmax)
101 { 102 {
102 if(rmin == rmax) << 103 if (rmin == rmax)
103 { 104 {
104 return rmin; 105 return rmin;
105 } 106 }
106 G4double k = G4UniformRand(); 107 G4double k = G4UniformRand();
107 return (rmin <= 0) ? rmax * std::sqrt(k) << 108 return (rmin <= 0) ? rmax*std::sqrt(k)
108 : std::sqrt(k * rmax * rm << 109 : std::sqrt(k*rmax*rmax + (1.-k)*rmin*rmin);
109 } 110 }
110 111
111 // ------------------------------------------- 112 // ---------------------------------------------------------------------------
112 // Returns a random point in ellipse (x/a)^2 + 113 // Returns a random point in ellipse (x/a)^2 + (y/b)^2 = 1
113 // (rejection sampling) 114 // (rejection sampling)
114 // 115 //
115 inline G4TwoVector G4RandomPointInEllipse(G4do 116 inline G4TwoVector G4RandomPointInEllipse(G4double a, G4double b)
116 { 117 {
117 G4double aa = (a * a == 0) ? 0 : 1 / (a * a) << 118 G4double aa = (a*a == 0) ? 0 : 1/(a*a);
118 G4double bb = (b * b == 0) ? 0 : 1 / (b * b) << 119 G4double bb = (b*b == 0) ? 0 : 1/(b*b);
119 for(G4int i = 0; i < 1000; ++i) << 120 for (G4int i=0; i<1000; ++i)
120 { 121 {
121 G4double x = a * (2 * G4UniformRand() - 1) << 122 G4double x = a*(2*G4UniformRand() - 1);
122 G4double y = b * (2 * G4UniformRand() - 1) << 123 G4double y = b*(2*G4UniformRand() - 1);
123 if(x * x * aa + y * y * bb <= 1) << 124 if (x*x*aa + y*y*bb <= 1) return G4TwoVector(x,y);
124 return G4TwoVector(x, y); <<
125 } 125 }
126 return G4TwoVector(0, 0); << 126 return G4TwoVector(0,0);
127 } 127 }
128 128
129 // ------------------------------------------- 129 // ---------------------------------------------------------------------------
130 // Returns a random point on ellipse (x/a)^2 + 130 // Returns a random point on ellipse (x/a)^2 + (y/b)^2 = 1
131 // (rejection sampling) 131 // (rejection sampling)
132 // 132 //
133 inline G4TwoVector G4RandomPointOnEllipse(G4do 133 inline G4TwoVector G4RandomPointOnEllipse(G4double a, G4double b)
134 { 134 {
135 G4double A = std::abs(a); << 135 G4double A = std::abs(a);
136 G4double B = std::abs(b); << 136 G4double B = std::abs(b);
137 G4double mu_max = std::max(A, B); << 137 G4double mu_max = std::max(A,B);
138 138
139 G4double x, y; << 139 G4double x,y;
140 for(G4int i = 0; i < 1000; ++i) << 140 for (G4int i=0; i<1000; ++i)
141 { 141 {
142 G4double phi = CLHEP::twopi * G4UniformRan << 142 G4double phi = CLHEP::twopi*G4UniformRand();
143 x = std::cos(phi); << 143 x = std::cos(phi);
144 y = std::sin(phi); << 144 y = std::sin(phi);
145 G4double mu = std::sqrt((B * x) * (B * x) << 145 G4double mu = std::sqrt((B*x)*(B*x) + (A*y)*(A*y));
146 if(mu_max * G4UniformRand() <= mu) << 146 if (mu_max*G4UniformRand() <= mu) break;
147 break; <<
148 } 147 }
149 return G4TwoVector(A * x, B * y); << 148 return G4TwoVector(A*x,B*y);
150 } 149 }
151 150
152 // ------------------------------------------- 151 // ---------------------------------------------------------------------------
153 // Returns a random point on ellipsoid (x/a)^2 152 // Returns a random point on ellipsoid (x/a)^2 + (y/b)^2 + (z/c)^2 = 1
154 // (rejection sampling) 153 // (rejection sampling)
155 // 154 //
156 inline G4ThreeVector G4RandomPointOnEllipsoid( << 155 inline
157 << 156 G4ThreeVector G4RandomPointOnEllipsoid(G4double a, G4double b, G4double c)
158 { 157 {
159 G4double A = std::abs(a); << 158 G4double A = std::abs(a);
160 G4double B = std::abs(b); << 159 G4double B = std::abs(b);
161 G4double C = std::abs(c); << 160 G4double C = std::abs(c);
162 G4double mu_max = std::max(std::max(A * B, A << 161 G4double mu_max = std::max(std::max(A*B,A*C),B*C);
163 162
164 G4ThreeVector p; 163 G4ThreeVector p;
165 for(G4int i = 0; i < 1000; ++i) << 164 for (G4int i=0; i<1000; ++i)
166 { 165 {
167 p = G4RandomDirection(); << 166 p = G4RandomDirection();
168 G4double xbc = p.x() * B * C; << 167 G4double xbc = p.x()*B*C;
169 G4double yac = p.y() * A * C; << 168 G4double yac = p.y()*A*C;
170 G4double zab = p.z() * A * B; << 169 G4double zab = p.z()*A*B;
171 G4double mu = std::sqrt(xbc * xbc + yac * << 170 G4double mu = std::sqrt(xbc*xbc + yac*yac + zab*zab);
172 if(mu_max * G4UniformRand() <= mu) << 171 if (mu_max*G4UniformRand() <= mu) break;
173 break; <<
174 } 172 }
175 return G4ThreeVector(A * p.x(), B * p.y(), C << 173 return G4ThreeVector(A*p.x(),B*p.y(),C*p.z());
176 } 174 }
177 175
178 #endif /* G4RANDOMTOOLS_HH */ << 176 #endif /* G4RANDOMTOOLS_HH */
179 177