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1 //
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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 //
30 // P. Arce, June-2014 Conversion neutron_hp to particle_hp
31 //
32 #include "G4ParticleHPArbitaryTab.hh"
33
34 #include "G4ios.hh"
35
36 G4double G4ParticleHPArbitaryTab::Sample(G4double anEnergy)
37 {
38 G4int i;
39 for (i = 0; i < nDistFunc; i++) {
40 if (anEnergy < theDistFunc[i].GetLabel()) break; // that is the energy we need
41 }
42 G4int low(0), high(0);
43 if (i == nDistFunc) {
44 low = i - 2;
45 high = i - 1;
46 }
47 else if (i == 0) {
48 if (nDistFunc == 0) {
49 G4cerr << "No distribution functions to sample "
50 << "from in G4ParticleHPArbitaryTab::Sample" << G4endl;
51 throw G4HadronicException(__FILE__, __LINE__, "nDistFunc==0");
52 }
53 return theDistFunc[0].Sample();
54 }
55 else {
56 low = i - 1;
57 high = i;
58 }
59 //************************************************************************
60 // EMendoza
61 /*
62 theBuffer.Merge(theManager.GetScheme(low), anEnergy,
63 theDistFunc+low, theDistFunc+high);
64 return theBuffer.Sample();
65 */
66 //************************************************************************
67 // New way to perform the 2D sampling:
68 G4double elow = theDistFunc[low].GetLabel();
69 G4double ehigh = theDistFunc[high].GetLabel();
70 G4double rval = (anEnergy - elow) / (ehigh - elow); // rval is 0 for elow and 1 for ehigh
71 G4double eoutlow = theLowThreshold[low] + rval * (theLowThreshold[high] - theLowThreshold[low]);
72 G4double eouthigh =
73 theHighThreshold[low] + rval * (theHighThreshold[high] - theHighThreshold[low]);
74 G4double rand = G4UniformRand();
75 G4double Eout_1 = 0, Eout_2 = 0;
76 if (rval < rand) {
77 Eout_1 = theDistFunc[low].Sample();
78 Eout_2 = eoutlow
79 + (Eout_1 - theLowThreshold[low]) * (eouthigh - eoutlow)
80 / (theHighThreshold[low] - theLowThreshold[low]);
81 }
82 else {
83 Eout_1 = theDistFunc[high].Sample();
84 Eout_2 = eoutlow
85 + (Eout_1 - theLowThreshold[high]) * (eouthigh - eoutlow)
86 / (theHighThreshold[high] - theLowThreshold[high]);
87 }
88 return Eout_2;
89
90 //************************************************************************
91 }
92