| Geant4 Cross Reference |
1 // 1
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18 // * This code implementation is the result
19 // * technical work of the GEANT4 collaboratio
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24 // *******************************************
25 //
26 #include "G4AngularDistributionNP.hh"
27 #include "G4PhysicalConstants.hh"
28 #include "G4SystemOfUnits.hh"
29 #include "Randomize.hh"
30 #include "G4ios.hh"
31
32 // Initialization of static data arrays:
33 #include "G4AngularDistributionNPData.hh"
34 #include "Randomize.hh"
35
36
37 G4double G4AngularDistributionNP::CosTheta(G4d
38 {
39 G4int verboseLevel=1;
40
41 G4double ek= ((S - sqr(m_1) -sqr(m_2) )/(2
42
43 // Find energy bin
44
45 G4int je1 = 0;
46 G4int je2 = NENERGY - 1;
47 G4int iterationsLeft=2*NENERGY +1;
48 do {
49 G4int midBin = (je1 + je2)/2;
50 if (ek < elab[midBin])
51 je2 = midBin;
52 else
53 je1 = midBin;
54 } while ( (je2 - je1) > 1 && --iterationsL
55 if ( iterationsLeft <= 0 ) {
56 G4Exception("G4AngularDistributionNP",
57 "Problem with energy bin (elab) d
58
59 }
60 // G4int j;
61 //std::abs(ek-elab[je1]) < std::abs(ek-ela
62 G4double delab = elab[je2] - elab[je1];
63
64 // Sample the angle
65
66 G4double sample = G4UniformRand();
67 G4int ke1 = 0;
68 G4int ke2 = NANGLE - 1;
69 G4double dsig = sig[je2][0] - sig[je1][0];
70 G4double rc = dsig/delab;
71 G4double b = sig[je1][0] - rc*elab[je1];
72 G4double sigint1 = rc*ek + b;
73 G4double sigint2 = 0.;
74
75 if (verboseLevel > 1) G4cout << "sample="
76 << ek << " "
77 << sigint1 <<
78 iterationsLeft= 2*NANGLE +1;
79 do {
80 G4int midBin = (ke1 + ke2)/2;
81 dsig = sig[je2][midBin] - sig[je1][midBi
82 rc = dsig/delab;
83 b = sig[je1][midBin] - rc*elab[je1];
84 G4double sigint = rc*ek + b;
85 if (sample < sigint) {
86 ke2 = midBin;
87 sigint2 = sigint;
88 }
89 else {
90 ke1 = midBin;
91 sigint1 = sigint;
92 }
93 if (verboseLevel > 1)G4cout << ke1 << "
94 << sigint1 <
95 } while ( (ke2 - ke1) > 1 && --iterationsL
96 if ( iterationsLeft <= 0 ) {
97 G4Exception("G4AngularDistributionNP",
98 "Problem with angular distributio
99 }
100
101 // sigint1 and sigint2 should be recoverab
102
103 // G4double dsig = sig[je2][ke1] - sig[
104 // G4double rc = dsig/delab;
105 // G4double b = sig[je1][ke1] - rc*elab
106 // G4double sigint1 = rc*ek + b;
107
108 // G4double dsig = sig[je2][ke2] - sig[
109 // G4double rc = dsig/delab;
110 // G4double b = sig[je1][ke2] - rc*elab
111 // G4double sigint2 = rc*ek + b;
112
113 dsig = sigint2 - sigint1;
114 rc = 1./dsig;
115 b = ke1 - rc*sigint1;
116 G4double kint = rc*sample + b;
117 G4double theta = (0.5 + kint)*pi/180.;
118
119 // G4int k;
120 //std::abs(sample-sig[j][ke1]) < std::abs(
121 // G4double theta = (0.5 + k)*pi/180.;
122
123 if (verboseLevel > 1) {
124 G4cout << " energy bin " << je1 << " e
125 G4cout << " angle bin " << kint << " a
126 }
127 G4double costh= std::cos(theta);
128 return costh;
129 }
130
131 G4double G4AngularDistributionNP::Phi() const
132 {
133 return twopi * G4UniformRand();
134 }
135