Geant4_10
G4NeutronHPArbitaryTab.cc
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25 //
26 // neutron_hp -- source file
27 // J.P. Wellisch, Nov-1996
28 // A prototype of the low energy neutron transport model.
29 //
31 #include "G4ios.hh"
32 
34  {
35  G4int i;
36  for(i=0;i<nDistFunc;i++)
37  {
38  if(anEnergy<theDistFunc[i].GetLabel()) break; // that is the energy we need
39  }
40  G4int low(0), high(0);
41  if(i==nDistFunc)
42  {
43  low = i-2;
44  high = i-1;
45  }
46  else if(i==0)
47  {
48  if(nDistFunc==0)
49  {
50  G4cerr << "No distribution functions to sample "
51  << "from in G4NeutronHPArbitaryTab::Sample"<<G4endl;
52  throw G4HadronicException(__FILE__, __LINE__, "nDistFunc==0");
53  }
54  else
55  {
56  return theDistFunc[0].Sample();
57  }
58  }
59  else
60  {
61  low = i-1;
62  high = i;
63  }
64  //************************************************************************
65  //EMendoza
66  /*
67  theBuffer.Merge(theManager.GetScheme(low), anEnergy,
68  theDistFunc+low, theDistFunc+high);
69  return theBuffer.Sample();
70  */
71  //************************************************************************
72  //New way to perform the 2D sampling:
73  G4double elow=theDistFunc[low].GetLabel();
74  G4double ehigh=theDistFunc[high].GetLabel();
75  G4double rval=(anEnergy-elow)/(ehigh-elow);//rval is 0 for elow and 1 for ehigh
76  G4double eoutlow=theLowThreshold[low]+rval*(theLowThreshold[high]-theLowThreshold[low]);
77  G4double eouthigh=theHighThreshold[low]+rval*(theHighThreshold[high]-theHighThreshold[low]);
78  G4double rand=G4UniformRand();
79  G4double Eout_1=0,Eout_2=0;
80  if(rval<rand){
81  Eout_1=theDistFunc[low].Sample();
82  Eout_2=eoutlow+(Eout_1-theLowThreshold[low])*(eouthigh-eoutlow)/(theHighThreshold[low]-theLowThreshold[low]);
83  }
84  else{
85  Eout_1=theDistFunc[high].Sample();
86  Eout_2=eoutlow+(Eout_1-theLowThreshold[high])*(eouthigh-eoutlow)/(theHighThreshold[high]-theLowThreshold[high]);
87  }
88  return Eout_2;
89 
90  //************************************************************************
91  }
int G4int
Definition: G4Types.hh:78
#define G4UniformRand()
Definition: Randomize.hh:87
#define G4endl
Definition: G4ios.hh:61
double G4double
Definition: G4Types.hh:76
G4double Sample(G4double anEnergy)
G4GLOB_DLL std::ostream G4cerr