| 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: G4ClassicalRK4.hh,v 1.10 2006/06/29 18:21:55 gunter Exp $
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| 28 | // GEANT4 tag $Name: geant4-09-02-cand-01 $
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| 29 | //
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| 30 | //
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| 31 | // class G4ClassicalRK4
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| 32 | //
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| 33 | // Class description:
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| 34 | //
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| 35 | // Integrate the equations of the motion of a particle in a magnetic field
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| 36 | // using the classical 4th Runge-Kutta method.
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| 37 |
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| 38 | // History:
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| 39 | // - Created: J.Apostolakis, V.Grichine - 30.1.97
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| 40 | // - Moved into G4MagErrorStepper: W.Wander <wwc@mit.edu> - 12/09/97
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| 41 | // -------------------------------------------------------------------
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| 42 |
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| 43 | #include "G4MagErrorStepper.hh"
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| 44 |
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| 45 | class G4ClassicalRK4 : public G4MagErrorStepper
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| 46 | {
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| 47 | public: // with description
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| 48 |
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| 49 | G4ClassicalRK4(G4EquationOfMotion *EquationMotion, G4int numberOfVariables = 6) ;
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| 50 |
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| 51 | ~G4ClassicalRK4() ;
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| 52 |
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| 53 | // A stepper that does not know about errors.
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| 54 | // It is used by the MagErrorStepper stepper.
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| 55 |
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| 56 | void DumbStepper( const G4double yIn[],
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| 57 | const G4double dydx[],
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| 58 | G4double h,
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| 59 | G4double yOut[] ) ;
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| 60 | // Given values for the variables y[0,..,n-1] and their derivatives
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| 61 | // dydx[0,...,n-1] known at x, use the classical 4th Runge-Kutta
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| 62 | // method to advance the solution over an interval h and return the
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| 63 | // incremented variables as yout[0,...,n-1], which not be a distinct
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| 64 | // array from y. The user supplies the routine RightHandSide(x,y,dydx),
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| 65 | // which returns derivatives dydx at x. The source is routine rk4 from
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| 66 | // NRC p. 712-713 .
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| 67 |
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| 68 | public: // without description
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| 69 |
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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 h,
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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 | G4ClassicalRK4(const G4ClassicalRK4&);
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| 85 | G4ClassicalRK4& operator=(const G4ClassicalRK4&);
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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 ; // is set default to 6 in constructor
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| 91 |
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| 92 | G4double *dydxm, *dydxt, *yt; // scratch space - not state
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| 93 | };
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