include/Geant4/G4VSIntegration.hh

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0025 //
0026 // G4VSIntegration
0027 //
0028 // Class description:
0029 //
0030 // Numerical algorithm for integration of probability density function
0031 // and sampling of the energy. Parameters of the algorithm should
0032 // be defined by consumer class via the InitialiseIntegrator(..) method.
0033 // The method is effective for the case of functions with a peak and long
0034 // tail. Tunning of parameters may increase efficiency of the algorithm.
0035 // The default set of parameters is optimized for the pre-compound model.
0036 //
0037 // Created 03.03.2025 V.Ivanchenko
0038 //
0039 // --------------------------------------------------------------------
0040
0041 #ifndef G4VSIntegration_HH
0042 #define G4VSIntegration_HH 1
0043
0044 #include "globals.hh"
0045
0046 class G4VSIntegration
0047 {
0048  public:
0049   G4VSIntegration() = default;
0050
0051   virtual ~G4VSIntegration() = default;
0052
0053   // this method should be implemented in a consumer class
0054   virtual G4double ProbabilityDensityFunction(G4double) = 0;
0055
0056   virtual const G4String& ModelName() const;
0057
0058   // initialisation before run called once
0059   // accuracy - accuracy of integration
0060   // fact1 - value < 1 to define energy E1: Pmax*fact = P(E1)
0061   //         and E2: P(E1)*fact = P(E2)
0062   // fact2 - value > 1 provides tolerance for max cross section
0063   // deltaE - the default step in energy
0064   // dmin, dmax - min and max values of step
0065   void InitialiseIntegrator(G4double accuracy, G4double fact1, G4double fact2,
0066                 G4double de, G4double dmin, G4double dmax);
0067
0068   // compute integral of probability density function
0069   G4double ComputeIntegral(const G4double emin, const G4double  emax);
0070
0071   // sample value according to probability density function
0072   // it is assumed that ComputeIntegral(emin, emax) was executed
0073   G4double SampleValue();
0074
0075   G4VSIntegration(const G4VSIntegration&) = delete;
0076   G4VSIntegration& operator=(const G4VSIntegration&) = delete;
0077   G4bool operator==(const G4VSIntegration &right) const = delete;
0078   G4bool operator!=(const G4VSIntegration &right) const = delete;
0079
0080   void SetVerbose(G4int verb) { fVerbose = verb; }
0081
0082 private:
0083
0084   G4double fAcc{0.001};    // accuracy of integration
0085   G4double fMinDelta{0.1}; // minimal step integration
0086   G4double fMaxDelta{2.0}; // maximal step integration
0087   G4double fDelta{1.0};    // the default step
0088   G4double fFactor1{0.25};
0089   G4double fFactor2{1.05};
0090
0091   // parameters describing function
0092   G4double fEmin{0.0};
0093   G4double fEmax{0.0};
0094   G4double fE1{0.0};
0095   G4double fP1{0.0};
0096   G4double fE2{0.0};
0097   G4double fP2{0.0};
0098   G4double fPmax{0.0};
0099
0100   G4int fVerbose{0};
0101   G4int fWarnLimit{4};
0102   G4int fnWarn{0};
0103
0104   G4String dummy{""};
0105 };
0106
0107 #endif