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 // 00027 // 00028 // $Id: G4RKG3_Stepper.hh 69786 2013-05-15 09:38:51Z gcosmo $ 00029 // 00030 // 00031 // 00032 // class G4RKG3_Stepper 00033 // 00034 // Class description: 00035 // 00036 // Integrator Runga-Kutta Stepper from Geant3. 00037 // 00038 // History: 00039 // - Created. J.Apostolakis, V.Grichine - 30.01.97 00040 // ------------------------------------------------------------------- 00041 00042 #ifndef G4RKG3_Stepper_hh 00043 #define G4RKG3_Stepper_hh 00044 00045 #include "G4Types.hh" 00046 #include "G4MagIntegratorStepper.hh" 00047 #include "G4ThreeVector.hh" 00048 00049 class G4Mag_EqRhs; 00050 00051 class G4RKG3_Stepper : public G4MagIntegratorStepper 00052 { 00053 public: // with description 00054 00055 G4RKG3_Stepper(G4Mag_EqRhs *EqRhs); 00056 // Integrate over 6 variables only: position & velocity. 00057 // Not implemented yet ! 00058 00059 ~G4RKG3_Stepper(); 00060 00061 void Stepper( const G4double yIn[], 00062 const G4double dydx[], 00063 G4double h, 00064 G4double yOut[], 00065 G4double yErr[] ); 00066 // The method which must be provided, even if less efficient. 00067 00068 G4double DistChord() const ; 00069 00070 void StepNoErr( const G4double tIn[8], 00071 const G4double dydx[6], 00072 G4double Step, 00073 G4double tOut[8], 00074 G4double B[3] ); 00075 // Integrator RK Stepper from G3 with only two field evaluation per 00076 // Step. It is used in propagation initial Step by small substeps 00077 // after solution error and delta geometry considerations. 00078 // B[3] is magnetic field which is passed from substep to substep. 00079 00080 void StepWithEst( const G4double tIn[8], 00081 const G4double dydx[6], 00082 G4double Step, 00083 G4double tOut[8], 00084 G4double& alpha2, 00085 G4double& beta2, 00086 const G4double B1[3], 00087 G4double B2[3] ); 00088 // Integrator for RK from G3 with evaluation of error in solution and delta 00089 // geometry based on naive similarity with the case of uniform magnetic field. 00090 // B1[3] is input and is the first magnetic field values 00091 // B2[3] is output and is the final magnetic field values. 00092 00093 public: // without description 00094 00095 G4int IntegratorOrder() const { return 4; } 00096 00097 private: 00098 00099 G4ThreeVector fyInitial, 00100 fyMidPoint, 00101 fyFinal; 00102 G4ThreeVector fpInitial; 00103 G4ThreeVector BfldIn; 00104 G4double hStep; 00105 }; 00106 00107 #endif