Geant4  10.02.p02
G4AngularDistributionPP.cc
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27 #include "G4PhysicalConstants.hh"
28 #include "G4SystemOfUnits.hh"
29 #include "Randomize.hh"
30 #include "G4ios.hh"
31 
32 // Initialization of static data arrays:
34 #include "Randomize.hh"
35 
36 
38 {
39  G4int verboseLevel=1;
40 
41  G4double ek= ((S - sqr(m_1) -sqr(m_2) )/(2*m_1) - m_1 )/GeV ; // kinetic energy in GeV
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 && --iterationsLeft > 0 ); /* Loop checking, 30-Oct-2015, G.Folger */
55  if ( iterationsLeft <= 0 ) {
56  G4Exception("G4AngularDistributionPP", "im_r_matrix020", FatalException,
57  "Problem with energy bin (elab) data");
58 
59  }
60  // G4int j;
61  //std::abs(ek-elab[je1]) < std::abs(ek-elab[je2]) ? j = je1 : j = je2;
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=" << sample << G4endl
76  << ek << " " << ke1 << " " << ke2 << " "
77  << sigint1 << " " << sigint2 << G4endl;
78 
79  iterationsLeft= 2*NANGLE +1;
80  do {
81  G4int midBin = (ke1 + ke2)/2;
82  dsig = sig[je2][midBin] - sig[je1][midBin];
83  rc = dsig/delab;
84  b = sig[je1][midBin] - rc*elab[je1];
85  G4double sigint = rc*ek + b;
86  if (sample < sigint) {
87  ke2 = midBin;
88  sigint2 = sigint;
89  }
90  else {
91  ke1 = midBin;
92  sigint1 = sigint;
93  }
94  if (verboseLevel > 1)G4cout << ke1 << " " << ke2 << " "
95  << sigint1 << " " << sigint2 << G4endl;
96  } while ( (ke2 - ke1) > 1 && --iterationsLeft > 0); /* Loop checking, 30-Oct-2015, G.Folger */
97  if ( iterationsLeft <= 0 ) {
98  G4Exception("G4AngularDistributionPP", "im_r_matrix021", FatalException,
99  "Problem with angular distribution (sig) data");
100  }
101 
102  // sigint1 and sigint2 should be recoverable from above loop
103 
104  // G4double dsig = sig[je2][ke1] - sig[je1][ke1];
105  // G4double rc = dsig/delab;
106  // G4double b = sig[je1][ke1] - rc*elab[je1];
107  // G4double sigint1 = rc*ek + b;
108 
109  // G4double dsig = sig[je2][ke2] - sig[je1][ke2];
110  // G4double rc = dsig/delab;
111  // G4double b = sig[je1][ke2] - rc*elab[je1];
112  // G4double sigint2 = rc*ek + b;
113 
114  dsig = sigint2 - sigint1;
115  rc = 1./dsig;
116  b = ke1 - rc*sigint1;
117  G4double kint = rc*sample + b;
118  G4double theta = (0.5 + kint)*pi/180.;
119 
120  // G4int k;
121  //std::abs(sample-sig[j][ke1]) < std::abs(sample-sig[j][ke2]) ? k = ke1 : k = ke2;
122  // G4double theta = (0.5 + k)*pi/180.;
123 
124  if (verboseLevel > 1) {
125  G4cout << " energy bin " << je1 << " energy=" << elab[je1] << G4endl;
126  G4cout << " angle bin " << kint << " angle=" << theta/degree << G4endl;
127  }
128  G4double costh= std::cos(theta);
129 // G4cout << "scattering angle hpw "<<costh<<" "<<s<<" "<<m1<<" "<<m2<<G4endl;
130  return costh;
131 }
132 
134 {
135  return twopi * G4UniformRand();
136 }
double S(double temp)
int G4int
Definition: G4Types.hh:78
virtual G4double Phi() const
#define G4UniformRand()
Definition: Randomize.hh:97
G4GLOB_DLL std::ostream G4cout
static const double twopi
Definition: G4SIunits.hh:75
static const double GeV
Definition: G4SIunits.hh:214
void G4Exception(const char *originOfException, const char *exceptionCode, G4ExceptionSeverity severity, const char *comments)
Definition: G4Exception.cc:41
static const double pi
Definition: G4SIunits.hh:74
static const double degree
Definition: G4SIunits.hh:143
#define G4endl
Definition: G4ios.hh:61
T sqr(const T &x)
Definition: templates.hh:145
double G4double
Definition: G4Types.hh:76
virtual G4double CosTheta(G4double s, G4double m1, G4double m2) const
static const G4float sig[NENERGY][NANGLE]
static const G4float elab[NENERGY]