| Geant4 Cross Reference |
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25 //
26 //
27 // Multibody "phase space" generator, which provides interface to
28 // algorithms for sampling. Momentum vectors are generated in the
29 // center-of-mass frame of the decay, and returned in a user-supplied
30 // buffer.
31 //
32 // Sampling algorithm is specified via constructor argument, either by
33 // code for centrally supplied algorithms (Kopylov, GENBOD, or NBody),
34 // or by pointer (which is owned by the generator).
35 //
36 // Author: Michael Kelsey (SLAC) <kelsey@slac.stanford.edu>
37
38 #ifndef G4HadDecayGenerator_HH
39 #define G4HadDecayGenerator_HH 1
40
41 #include "globals.hh"
42 #include "G4LorentzVector.hh"
43 #include <vector>
44
45 class G4ParticleDefinition;
46 class G4VHadDecayAlgorithm;
47
48
49 class G4HadDecayGenerator {
50 public:
51 // Flags to select algorithm by code in constructor
52 enum Algorithm { NONE=0, Kopylov=1, GENBOD=2, NBody=3 };
53
54 // Specify "standard" algorithm by code or by object (takes ownership)
55 G4HadDecayGenerator(Algorithm alg=Kopylov, G4int verbose=0);
56 G4HadDecayGenerator(G4VHadDecayAlgorithm* alg, G4int verbose=0);
57 virtual ~G4HadDecayGenerator();
58
59 // Enable (or disable if 0) diagnostic messages
60 void SetVerboseLevel(G4int verbose);
61 const G4String& GetAlgorithmName() const;
62
63 // Initial state (rest mass) and list of final masses
64 G4bool Generate(G4double initialMass,
65 const std::vector<G4double>& masses,
66 std::vector<G4LorentzVector>& finalState);
67
68 // Initial state particle and list of final masses
69 G4bool Generate(const G4ParticleDefinition* initialPD,
70 const std::vector<G4double>& masses,
71 std::vector<G4LorentzVector>& finalState);
72
73 // Initial state (frame) and list of final masses
74 // Final state particles will be boosted to initial-state frame
75 G4bool Generate(const G4LorentzVector& initialState,
76 const std::vector<G4double>& masses,
77 std::vector<G4LorentzVector>& finalState);
78
79 protected:
80 // Special case for one-body final state
81 G4bool GenerateOneBody(G4double initialMass,
82 const std::vector<G4double>& masses,
83 std::vector<G4LorentzVector>& finalState) const;
84
85 // Special function used by constructor for unrecognized algorithm code
86 void ReportInvalidAlgorithm(Algorithm alg) const;
87 void ReportMissingAlgorithm() const;
88
89 protected:
90 // SPECIAL FUNCTION FOR SUBCLASSES: A subclass may implement a
91 // collection of algorithms, to be switched on an event-by-event
92 // basis. This function allows the subclass to switch the "active"
93 // algorithm before Generate() is called.
94 //
95 // If this function is used by the subclass, then the subclass has
96 // ownership of _all_ instantiated algorithms, and should delete
97 // them in its own dtor. The subclass dtor must also call
98 // UseAlgorithm(0) to set the base algorithm to a null pointer, to
99 // prevent a double-delete error.
100 void UseAlgorithm(G4VHadDecayAlgorithm* alg) { theAlgorithm = alg; }
101
102 G4int verboseLevel;
103 G4VHadDecayAlgorithm* theAlgorithm;
104 };
105
106 #endif /* G4HadDecayGenerator_HH */
107