00001 // 00002 // ******************************************************************** 00003 // * License and Disclaimer * 00004 // * * 00005 // * The Geant4 software is copyright of the Copyright Holders of * 00006 // * the Geant4 Collaboration. It is provided under the terms and * 00007 // * conditions of the Geant4 Software License, included in the file * 00008 // * LICENSE and available at http://cern.ch/geant4/license . These * 00009 // * include a list of copyright holders. * 00010 // * * 00011 // * Neither the authors of this software system, nor their employing * 00012 // * institutes,nor the agencies providing financial support for this * 00013 // * work make any representation or warranty, express or implied, * 00014 // * regarding this software system or assume any liability for its * 00015 // * use. Please see the license in the file LICENSE and URL above * 00016 // * for the full disclaimer and the limitation of liability. * 00017 // * * 00018 // * This code implementation is the result of the scientific and * 00019 // * technical work of the GEANT4 collaboration. * 00020 // * By using, copying, modifying or distributing the software (or * 00021 // * any work based on the software) you agree to acknowledge its * 00022 // * use in resulting scientific publications, and indicate your * 00023 // * acceptance of all terms of the Geant4 Software license. * 00024 // ******************************************************************** 00025 // 00026 // $Id: G4MagIntegratorStepper.hh 69786 2013-05-15 09:38:51Z gcosmo $ 00027 // 00028 // 00029 // class G4MagIntegratorStepper 00030 // 00031 // Class description: 00032 // 00033 // Abstract base class for integrator of particle's equation of motion, 00034 // used in tracking in space dependent magnetic field 00035 // 00036 // A Stepper must integrate over NumberOfVariables elements, 00037 // and also copy (from input to output) any of NoStateVariables 00038 // not included in the NumberOfVariables. 00039 // 00040 // So it is expected that NoStateVariables >= NumberOfVariables 00041 00042 // History: 00043 // - 15.01.97 J. Apostolakis (J.Apostolakis@cern.ch) 00044 // -------------------------------------------------------------------- 00045 00046 #ifndef G4MAGIntegratorSTEPPER 00047 #define G4MAGIntegratorSTEPPER 00048 00049 #include "G4Types.hh" 00050 #include "G4EquationOfMotion.hh" 00051 00052 class G4MagIntegratorStepper 00053 { 00054 public: // with description 00055 00056 G4MagIntegratorStepper(G4EquationOfMotion *Equation, 00057 G4int numIntegrationVariables, 00058 G4int numStateVariables=12); 00059 virtual ~G4MagIntegratorStepper(); 00060 // Constructor and destructor. No actions. 00061 00062 virtual void Stepper( const G4double y[], 00063 const G4double dydx[], 00064 G4double h, 00065 G4double yout[], 00066 G4double yerr[] ) = 0 ; 00067 // The stepper for the Runge Kutta integration. 00068 // The stepsize is fixed, with the Step size given by h. 00069 // Integrates ODE starting values y[0 to 6]. 00070 // Outputs yout[] and its estimated error yerr[]. 00071 00072 virtual G4double DistChord() const = 0; 00073 // Estimate the maximum distance of a chord from the true path 00074 // over the segment last integrated. 00075 00076 virtual void ComputeRightHandSide( const G4double y[], G4double dydx[] ); 00077 // Must compute the RightHandSide as in the method below 00078 // Optionally can cache the input y[] and the dydx[] values computed. 00079 00080 inline void NormaliseTangentVector( G4double vec[6] ); 00081 // Simple utility function to (re)normalise 'unit velocity' vector. 00082 00083 inline void NormalisePolarizationVector( G4double vec[12] ); 00084 // Simple utility function to (re)normalise 'unit spin' vector. 00085 00086 inline void RightHandSide( const double y[], double dydx[] ); 00087 // Utility method to supply the standard Evaluation of the 00088 // Right Hand side of the associated equation. 00089 00090 00091 inline G4int GetNumberOfVariables() const; 00092 // Get the number of variables that the stepper will integrate over. 00093 00094 // void SetNumberOfVariables(G4int newNo); // Dangerous & obsolete ... 00095 00096 inline G4int GetNumberOfStateVariables() const; 00097 // Get the number of variables of state variables (>= above, integration) 00098 00099 virtual G4int IntegratorOrder() const = 0; 00100 // Returns the order of the integrator 00101 // i.e. its error behaviour is of the order O(h^order). 00102 00103 inline G4EquationOfMotion *GetEquationOfMotion(); 00104 // As some steppers (eg RKG3) require other methods of Eq_Rhs 00105 // this function allows for access to them. 00106 inline void SetEquationOfMotion(G4EquationOfMotion* newEquation); 00107 00108 private: 00109 00110 G4MagIntegratorStepper(const G4MagIntegratorStepper&); 00111 G4MagIntegratorStepper& operator=(const G4MagIntegratorStepper&); 00112 // Private copy constructor and assignment operator. 00113 00114 private: 00115 00116 G4EquationOfMotion *fEquation_Rhs; 00117 const G4int fNoIntegrationVariables; // Number of Variables in integration 00118 const G4int fNoStateVariables; // Number required for FieldTrack 00119 // const G4int fNumberOfVariables; 00120 }; 00121 00122 #include "G4MagIntegratorStepper.icc" 00123 00124 #endif /* G4MAGIntegratorSTEPPER */