include/Geant4/G4VelocityTable.hh

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0024 // ********************************************************************
0025 //
0026 // G4VelocityTable
0027 //
0028 // Class description:
0029 //
0030 // This class keeps a table of velocity as a function of the ratio
0031 // kinetic erngy and mass. G4VelocityTable is used by
0032 // G4Track::CalculateVelocity().
0033
0034 // Author: Hisaya Kurashige,  17 August 2011
0035 // --------------------------------------------------------------------
0036 #ifndef G4VelocityTable_hh
0037 #define G4VelocityTable_hh 1
0038
0039 #include <vector>
0040 #include <iostream>
0041
0042 #include "globals.hh"
0043 #include "G4ios.hh"
0044 #include "G4ThreadLocalSingleton.hh"
0045
0046 class G4VelocityTable
0047 {
0048   friend class G4ThreadLocalSingleton<G4VelocityTable>;
0049
0050   using G4VTDataVector = std::vector<G4double>;
0051
0052   public:
0053
0054     G4double Value(G4double theEnergy);
0055       // Get the cross-section/energy-loss value corresponding to the
0056       // given energy. An appropriate interpolation is used to calculate
0057       // the value
0058
0059     static G4VelocityTable* GetVelocityTable();
0060
0061     static void SetVelocityTableProperties(G4double t_max, G4double t_min,
0062                                            G4int nbin);
0063     static G4double GetMaxTOfVelocityTable();
0064     static G4double GetMinTOfVelocityTable();
0065     static G4int GetNbinOfVelocityTable();
0066
0067   private:
0068
0069     G4VelocityTable();
0070     ~G4VelocityTable();
0071
0072     void PrepareVelocityTable();
0073
0074     std::size_t FindBinLocation(G4double theEnergy) const;
0075       // Find the bin# in which theEnergy belongs - pure virtual function
0076
0077     inline G4double Interpolation() const;
0078
0079     // --------------------------------------------------------------------
0080
0081     G4double edgeMin = 0.0;  // Energy of first point
0082     G4double edgeMax = 0.0;  // Energy of the last point
0083
0084     std::size_t numberOfNodes = 0;
0085
0086     G4VTDataVector dataVector;     // Vector to keep the crossection/energyloss
0087     G4VTDataVector binVector;      // Vector to keep energy
0088     G4VTDataVector secDerivative;  // Vector to keep second derivatives
0089
0090     G4double dBin = 0.0;     // Bin width - useful only for fixed binning
0091     G4double baseBin = 0.0;  // Set this in constructor for performance
0092
0093     G4double lastEnergy = -DBL_MAX;  // Cache the last input value
0094     G4double lastValue = 0.0;        // Cache the last output value
0095     std::size_t lastBin = 0;         // Cache the last bin location
0096
0097     static G4ThreadLocal G4VelocityTable* theInstance;
0098
0099     G4double maxT = 1000.0;
0100     G4double minT = 0.0001;
0101     G4int NbinT = 500;
0102 };
0103
0104 // ----------------------
0105 // Inline methods
0106 // ----------------------
0107
0108 inline G4double G4VelocityTable::Interpolation() const
0109 {
0110   // Linear interpolation is used to get the value. If the give energy
0111   // is in the highest bin, no interpolation will be Done. Because
0112   // there is an extra bin hidden from a user at locBin=numberOfBin,
0113   // the following interpolation is valid even the current locBin=
0114   // numberOfBin-1.
0115
0116   G4double intplFactor =
0117     (lastEnergy - binVector[lastBin]) /
0118     (binVector[lastBin + 1] - binVector[lastBin]);  // Interpol. factor
0119
0120   return dataVector[lastBin] +
0121          (dataVector[lastBin + 1] - dataVector[lastBin]) * intplFactor;
0122 }
0123
0124 #endif