| Geant4 Cross Reference |
1 //
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24 // ********************************************************************
25 //
26 // G4TemplateRNGHelper
27 //
28 // Class description:
29 //
30 // Helper class for RNG Engine seeds.
31 // Used in MT builds to guarantee event reproducibility.
32 // The function of this class is to return a RNG Engine seed given its index.
33 // It is a simple templated container that allows to add seeds (AddOneSeed)
34 // and retrieve a seed (GetSeed) by index.
35 //
36 // The normal use is with G4RNGHelper where each element of the container
37 // represents a seed. To enforce strong-reproducibility the variant with
38 // the RNG Engine status file names is available.
39
40 // Author: A.Dotti (SLAC), 5 July 2013
41 // --------------------------------------------------------------------
42 #ifndef G4TemplateRNGHelper_hh
43 #define G4TemplateRNGHelper_hh 1
44
45 #include "globals.hh"
46
47 #include <queue>
48 #include <vector>
49
50 template<class T>
51 class G4TemplateRNGHelper
52 {
53 public:
54 using SeedsQueue = std::vector<T>;
55 using SeedsQueueSize_type = typename SeedsQueue::size_type;
56
57 public:
58 // The container is modeled as a (shared) singleton
59 static G4TemplateRNGHelper<T>* GetInstance();
60 static G4TemplateRNGHelper<T>* GetInstanceIfExist();
61 virtual ~G4TemplateRNGHelper();
62
63 // Returns seed given id
64 virtual const T GetSeed(const G4int& sdId)
65 {
66 G4int seedId = sdId - 2 * offset;
67 if (seedId < static_cast<G4int>(seeds.size())) {
68 T& seed = seeds[seedId];
69 return seed;
70 }
71 G4ExceptionDescription msg;
72 msg << "No seed number " << seedId << "(" << seeds.size() << " available)\n"
73 << " Original seed number " << sdId << " filled so far " << offset;
74 G4Exception("G4RNGHelper::GetSeed", "Run0115", FatalException, msg);
75 return T();
76 }
77
78 // Adds one seed to the collection
79 void AddOneSeed(const T& seed) { seeds.push_back(seed); }
80
81 // Fills N primary seed pairs
82 void Fill(G4double* dbl, G4int nev, G4int nev_tot, G4int nrpe)
83 {
84 seeds.clear();
85 for (G4int i = 0; i < nrpe * nev; ++i) {
86 seeds.push_back((G4long)(100000000L * dbl[i]));
87 }
88 offset = 0;
89 nev_filled = nev;
90 nev_total = nev_tot;
91 nRandParEvent = nrpe;
92 }
93
94 void Refill(G4double* dbl, G4int nev)
95 {
96 if (nev == 0) return;
97 seeds.clear();
98 for (G4int i = 0; i < nRandParEvent * nev; ++i) {
99 seeds.push_back((G4long)(100000000L * dbl[i]));
100 }
101 offset += nev_filled;
102 nev_filled = nev;
103 }
104
105 // Number of available seeds
106 const SeedsQueueSize_type GetNumberSeeds() const { return seeds.size(); }
107
108 // Empty the seeds container
109 virtual void Clear() { seeds.clear(); }
110
111 protected:
112 SeedsQueue seeds;
113 // Note: following numbers are number of events.
114 // seeds are generated for nRandParEvent times n_event
115 G4int offset = 0;
116 G4int nev_filled = 0;
117 G4int nev_total = 0;
118 G4int nRandParEvent = 0;
119
120 private:
121 G4TemplateRNGHelper() = default;
122
123 private:
124 static G4TemplateRNGHelper<T>* instance;
125 };
126
127 using G4RNGHelper = G4TemplateRNGHelper<G4long>;
128 using G4StringRNGHelper = G4TemplateRNGHelper<G4String>;
129 using G4SeedsQueue = std::queue<G4long>;
130
131 #endif
132