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25 // 25 //
>> 26 // $Id$
26 // 27 //
27 /// \file GB05BOptnSplitAndKillByCrossSection. 28 /// \file GB05BOptnSplitAndKillByCrossSection.cc
28 /// \brief Implementation of the GB05BOptnSpli 29 /// \brief Implementation of the GB05BOptnSplitAndKillByCrossSection class
29 30
30 #include "GB05BOptnSplitAndKillByCrossSection. <<
31 <<
32 #include "Randomize.hh" 31 #include "Randomize.hh"
>> 32 #include "GB05BOptnSplitAndKillByCrossSection.hh"
33 33
34 //....oooOO0OOooo........oooOO0OOooo........oo 34 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
35 35
36 GB05BOptnSplitAndKillByCrossSection::GB05BOptn 36 GB05BOptnSplitAndKillByCrossSection::GB05BOptnSplitAndKillByCrossSection(G4String name)
37 : G4VBiasingOperation(name), fParticleChange << 37 : G4VBiasingOperation(name),
>> 38 fParticleChange(),
>> 39 fInteractionLength(-1.0)
38 {} 40 {}
39 41
40 //....oooOO0OOooo........oooOO0OOooo........oo 42 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
41 43
42 GB05BOptnSplitAndKillByCrossSection::~GB05BOpt << 44 GB05BOptnSplitAndKillByCrossSection::~GB05BOptnSplitAndKillByCrossSection()
>> 45 {}
43 46
44 //....oooOO0OOooo........oooOO0OOooo........oo 47 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
45 48
46 G4double GB05BOptnSplitAndKillByCrossSection:: << 49 G4double GB05BOptnSplitAndKillByCrossSection::
47 << 50 DistanceToApplyOperation( const G4Track*,
>> 51 G4double,
>> 52 G4ForceCondition* condition)
48 { 53 {
49 *condition = NotForced; 54 *condition = NotForced;
50 55
51 // -- Sample the exponential law using the t 56 // -- Sample the exponential law using the total interaction length of processes
52 // -- to couterbalance for: 57 // -- to couterbalance for:
53 G4double proposedStepLength = -std::log(G4Un << 58 G4double proposedStepLength = -std::log( G4UniformRand() ) * fInteractionLength;
54 << 59
55 return proposedStepLength; 60 return proposedStepLength;
56 } 61 }
57 62
58 //....oooOO0OOooo........oooOO0OOooo........oo 63 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
59 64
60 G4VParticleChange* << 65 G4VParticleChange*
61 GB05BOptnSplitAndKillByCrossSection::GenerateB << 66 GB05BOptnSplitAndKillByCrossSection::GenerateBiasingFinalState( const G4Track* track,
>> 67 const G4Step* )
62 { 68 {
>> 69
63 // -- This method is called if we have limit 70 // -- This method is called if we have limited the step.
64 // -- We hence make the splitting or killing 71 // -- We hence make the splitting or killing.
65 72
66 // Get track weight: 73 // Get track weight:
67 G4double initialWeight = track->GetWeight(); 74 G4double initialWeight = track->GetWeight();
68 << 75
69 // The "particle change" is the object to be 76 // The "particle change" is the object to be used to communicate to
70 // the tracking the update of the primary st 77 // the tracking the update of the primary state and/or creation
71 // secondary tracks. 78 // secondary tracks.
72 fParticleChange.Initialize(*track); 79 fParticleChange.Initialize(*track);
73 80
74 // -- Splitting and killing factors. 81 // -- Splitting and killing factors.
75 // -- They are taken the same, but the killi 82 // -- They are taken the same, but the killing factor can be make bigger.
76 G4double splittingFactor = 2.0; << 83 G4double splittingFactor = 2.0;
77 G4double killingFactor = 2.0; << 84 G4double killingFactor = 2.0;
78 85
79 if (track->GetMomentumDirection().z() > 0) { <<
80 // -- We split if the track is moving forw <<
81 86
82 // Define the tracks weight: << 87 if ( track->GetMomentumDirection().z() > 0 )
83 G4double weightOfTrack = initialWeight / s << 88 {
84 << 89 // -- We split if the track is moving forward:
85 // Ask currect track weight to be changed << 90
86 fParticleChange.ProposeParentWeight(weight << 91 // Define the tracks weight:
87 // Now make clones of this track (this is << 92 G4double weightOfTrack = initialWeight/splittingFactor;
88 // we will then have the primary and clone << 93
89 // splitting by a factor 2: << 94 // Ask currect track weight to be changed to new value:
90 G4Track* clone = new G4Track(*track); << 95 fParticleChange.ProposeParentWeight( weightOfTrack );
91 clone->SetWeight(weightOfTrack); << 96 // Now make clones of this track (this is the actual splitting):
92 fParticleChange.AddSecondary(clone); << 97 // we will then have the primary and clone of it, hence the
93 // -- Below's call added for safety & illu << 98 // splitting by a factor 2:
94 // -- modify the clone (ie : daughter) wei << 99 G4Track* clone = new G4Track( *track );
95 // -- primary. Here call not mandatory and << 100 clone->SetWeight( weightOfTrack );
96 fParticleChange.SetSecondaryWeightByProces << 101 fParticleChange.AddSecondary( clone );
97 } << 102 // -- Below's call added for safety & illustration : inform particle change to not
98 else { << 103 // -- modify the clone (ie : daughter) weight to male it that of the
99 // -- We apply Russian roulette if the tra << 104 // -- primary. Here call not mandatory and both tracks have same weights.
100 << 105 fParticleChange.SetSecondaryWeightByProcess(true);
101 // Shoot a random number (in ]0,1[ segment <<
102 G4double random = G4UniformRand(); <<
103 G4double killingProbability = 1.0 - 1.0 / <<
104 if (random < killingProbability) { <<
105 // We ask for the the track to be killed <<
106 fParticleChange.ProposeTrackStatus(fStop <<
107 } 106 }
108 else { << 107 else
109 // In this case, the track survives. We << 108 {
110 // to conserve weight among killed and s << 109 // -- We apply Russian roulette if the track is moving backward:
111 fParticleChange.ProposeParentWeight(init << 110
>> 111 // Shoot a random number (in ]0,1[ segment):
>> 112 G4double random = G4UniformRand();
>> 113 G4double killingProbability = 1.0 - 1.0/killingFactor;
>> 114 if ( random < killingProbability )
>> 115 {
>> 116 // We ask for the the track to be killed:
>> 117 fParticleChange.ProposeTrackStatus(fStopAndKill);
>> 118 }
>> 119 else
>> 120 {
>> 121 // In this case, the track survives. We change its weight
>> 122 // to conserve weight among killed and survival tracks:
>> 123 fParticleChange.ProposeParentWeight( initialWeight*killingFactor );
>> 124 }
112 } 125 }
113 } << 126
114 <<
115 return &fParticleChange; 127 return &fParticleChange;
>> 128
116 } 129 }
117 130
118 //....oooOO0OOooo........oooOO0OOooo........oo 131 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
119 132