| 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: G4ExplicitEuler.cc,v 1.8 2006/06/29 18:23:53 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 | // Explicit Euler: x_1 = x_0 + h * dx_0 |
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| 32 | // |
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| 33 | // most simple approach for solving linear differential equations. |
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| 34 | // Take the current derivative and add it to the current position. |
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| 35 | // |
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| 36 | // W.Wander <wwc@mit.edu> 12/09/97 |
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| 37 | // ------------------------------------------------------------------- |
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| 38 | |
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| 39 | #include "G4ExplicitEuler.hh" |
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| 40 | #include "G4ThreeVector.hh" |
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| 41 | |
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| 42 | ////////////////////////////////////////////////////////////////////////// |
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| 43 | // |
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| 44 | // Constructor |
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| 45 | |
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| 46 | G4ExplicitEuler::G4ExplicitEuler(G4EquationOfMotion* EqRhs, |
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| 47 | G4int numberOfVariables) |
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| 48 | : G4MagErrorStepper(EqRhs, numberOfVariables) |
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| 49 | { |
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| 50 | } |
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| 51 | |
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| 52 | |
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| 53 | /////////////////////////////////////////////////////////////////////// |
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| 54 | // |
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| 55 | // Destructor |
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| 56 | |
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| 57 | G4ExplicitEuler::~G4ExplicitEuler() |
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| 58 | { |
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| 59 | } |
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| 60 | |
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| 61 | |
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| 62 | /////////////////////////////////////////////////////////////////////// |
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| 63 | // |
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| 64 | // |
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| 65 | |
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| 66 | void |
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| 67 | G4ExplicitEuler::DumbStepper( const G4double yIn[], |
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| 68 | const G4double dydx[], |
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| 69 | G4double h, |
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| 70 | G4double yOut[] ) |
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| 71 | { |
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| 72 | const G4int numberOfVariables= GetNumberOfVariables(); |
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| 73 | |
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| 74 | // Initialise time to t0, needed when it is not updated by the integration. |
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| 75 | // yOut[7] = yIn[7]; // Better to set it to NaN; // TODO |
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| 76 | |
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| 77 | G4int i; |
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| 78 | |
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| 79 | for(i=0;i< numberOfVariables;i++) |
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| 80 | { |
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| 81 | yOut[i] = yIn[i] + h*dydx[i] ; // 1st and only Step |
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| 82 | } |
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| 83 | |
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| 84 | return ; |
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| 85 | } |
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