| 1 | // |
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| 2 | // ******************************************************************** |
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| 3 | // * License and Disclaimer * |
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| 4 | // * * |
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| 5 | // * The Geant4 software is copyright of the Copyright Holders of * |
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| 6 | // * the Geant4 Collaboration. It is provided under the terms and * |
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| 7 | // * conditions of the Geant4 Software License, included in the file * |
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| 8 | // * LICENSE and available at http://cern.ch/geant4/license . These * |
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| 9 | // * include a list of copyright holders. * |
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| 10 | // * * |
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| 11 | // * Neither the authors of this software system, nor their employing * |
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| 12 | // * institutes,nor the agencies providing financial support for this * |
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| 13 | // * work make any representation or warranty, express or implied, * |
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| 14 | // * regarding this software system or assume any liability for its * |
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| 15 | // * use. Please see the license in the file LICENSE and URL above * |
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| 16 | // * for the full disclaimer and the limitation of liability. * |
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| 17 | // * * |
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| 18 | // * This code implementation is the result of the scientific and * |
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| 19 | // * technical work of the GEANT4 collaboration. * |
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| 20 | // * By using, copying, modifying or distributing the software (or * |
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| 21 | // * any work based on the software) you agree to acknowledge its * |
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| 22 | // * use in resulting scientific publications, and indicate your * |
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| 23 | // * acceptance of all terms of the Geant4 Software license. * |
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| 24 | // ******************************************************************** |
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| 25 | // |
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| 26 | // |
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| 27 | // $Id: G4CashKarpRKF45.hh,v 1.11 2008/01/11 15:23:54 japost Exp $ |
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| 28 | // GEANT4 tag $Name: geant4-09-04-beta-01 $ |
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| 29 | // |
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| 30 | // |
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| 31 | // class G4CashKarpRKF45 |
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| 32 | // |
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| 33 | // Class description: |
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| 34 | // |
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| 35 | // The Cash-Karp Runge-Kutta-Fehlberg 4/5 method is an embedded fourth |
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| 36 | // order method (giving fifth-order accuracy) for the solution of an ODE. |
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| 37 | // Two different fourth order estimates are calculated; their difference |
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| 38 | // gives an error estimate. [ref. Numerical Recipes in C, 2nd Edition] |
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| 39 | // It is used to integrate the equations of the motion of a particle |
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| 40 | // in a magnetic field. |
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| 41 | |
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| 42 | // History: |
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| 43 | // - Created. J.Apostolakis, V.Grichine - 30.1.97 |
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| 44 | // ------------------------------------------------------------------- |
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| 45 | |
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| 46 | #ifndef G4CashKARP_RKF45 |
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| 47 | #define G4CashKARP_RKF45 |
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| 48 | |
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| 49 | #include "G4MagIntegratorStepper.hh" |
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| 50 | |
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| 51 | class G4CashKarpRKF45 : public G4MagIntegratorStepper |
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| 52 | { |
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| 53 | |
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| 54 | public: // with description |
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| 55 | |
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| 56 | G4CashKarpRKF45( G4EquationOfMotion *EqRhs, |
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| 57 | G4int numberOfVariables = 6, |
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| 58 | G4bool primary= true ) ; |
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| 59 | ~G4CashKarpRKF45() ; |
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| 60 | |
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| 61 | void Stepper( const G4double y[], |
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| 62 | const G4double dydx[], |
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| 63 | G4double h, |
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| 64 | G4double yout[], |
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| 65 | G4double yerr[] ) ; |
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| 66 | |
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| 67 | public: // without description |
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| 68 | |
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| 69 | G4double DistChord() const; |
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| 70 | G4int IntegratorOrder() const { return 4; } |
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| 71 | |
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| 72 | private: |
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| 73 | |
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| 74 | void StepWithEst( const G4double yIn[], |
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| 75 | const G4double dydx[], |
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| 76 | G4double Step, |
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| 77 | G4double yOut[], |
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| 78 | G4double& alpha2, |
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| 79 | G4double& beta2, |
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| 80 | const G4double B1[], |
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| 81 | G4double B2[] ); |
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| 82 | // No longer used. Obsolete. |
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| 83 | |
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| 84 | G4CashKarpRKF45(const G4CashKarpRKF45&); |
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| 85 | G4CashKarpRKF45& operator=(const G4CashKarpRKF45&); |
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| 86 | // Private copy constructor and assignment operator. |
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| 87 | |
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| 88 | private: |
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| 89 | |
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| 90 | // G4int fNumberOfVariables ; // Already kept in G4MagIntegratorStepper |
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| 91 | G4double *ak2, *ak3, *ak4, *ak5, *ak6, *ak7, *yTemp, *yIn; // scratch space |
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| 92 | |
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| 93 | // for DistChord calculations |
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| 94 | |
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| 95 | G4double fLastStepLength; |
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| 96 | G4double *fLastInitialVector, *fLastFinalVector, |
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| 97 | *fLastDyDx, *fMidVector, *fMidError; |
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| 98 | G4CashKarpRKF45* fAuxStepper; |
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| 99 | }; |
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| 100 | |
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| 101 | #endif /* G4CashKARP_RKF45 */ |
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