[831] | 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: G4SimpleHeum.cc,v 1.8 2006/06/29 18:24:51 gunter Exp $ |
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[850] | 28 | // GEANT4 tag $Name: HEAD $ |
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[831] | 29 | // |
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| 30 | // Simple Heum: |
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| 31 | // x_1 = x_0 + h * |
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| 32 | // 1/4 * dx(t0,x0) + |
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| 33 | // 3/4 * dx(t0+2/3*h, x0+2/3*h*(dx(t0+h/3,x0+h/3*dx(t0,x0)))) |
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| 34 | // |
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| 35 | // Third order solver. |
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| 36 | // |
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| 37 | // W.Wander <wwc@mit.edu> 12/09/97 |
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| 38 | // ------------------------------------------------------------------- |
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| 39 | |
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| 40 | #include "G4SimpleHeum.hh" |
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| 41 | #include "G4ThreeVector.hh" |
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| 42 | |
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| 43 | /////////////////////////////////////////////////////////////////////////// |
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| 44 | // |
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| 45 | // Constructor |
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| 46 | |
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| 47 | G4SimpleHeum::G4SimpleHeum(G4EquationOfMotion *EqRhs, G4int num_variables): |
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| 48 | G4MagErrorStepper(EqRhs, num_variables), |
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| 49 | fNumberOfVariables(num_variables) |
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| 50 | { |
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| 51 | dydxTemp = new G4double[fNumberOfVariables] ; |
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| 52 | dydxTemp2 = new G4double[fNumberOfVariables] ; |
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| 53 | yTemp = new G4double[fNumberOfVariables] ; |
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| 54 | yTemp2 = new G4double[fNumberOfVariables] ; |
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| 55 | } |
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| 56 | |
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| 57 | |
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| 58 | ////////////////////////////////////////////////////////////////////////// |
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| 59 | // |
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| 60 | // Destructor |
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| 61 | |
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| 62 | G4SimpleHeum::~G4SimpleHeum() |
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| 63 | { |
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| 64 | delete[] dydxTemp; |
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| 65 | delete[] dydxTemp2; |
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| 66 | delete[] yTemp; |
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| 67 | delete[] yTemp2; |
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| 68 | } |
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| 69 | |
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| 70 | |
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| 71 | ////////////////////////////////////////////////////////////////////// |
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| 72 | // |
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| 73 | // |
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| 74 | |
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| 75 | void |
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| 76 | G4SimpleHeum::DumbStepper( const G4double yIn[], |
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| 77 | const G4double dydx[], |
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| 78 | G4double h, |
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| 79 | G4double yOut[]) |
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| 80 | { |
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| 81 | // const G4int nvar = 6 ; |
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| 82 | |
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| 83 | G4int i; |
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| 84 | |
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| 85 | for( i = 0; i < fNumberOfVariables; i++ ) |
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| 86 | { |
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| 87 | yTemp[i] = yIn[i] + (1.0/3.0) * h * dydx[i] ; |
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| 88 | } |
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| 89 | |
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| 90 | RightHandSide(yTemp,dydxTemp); |
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| 91 | |
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| 92 | for( i = 0; i < fNumberOfVariables; i++ ) |
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| 93 | { |
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| 94 | yTemp2[i] = yIn[i] + (2.0/3.0) * h * dydxTemp[i] ; |
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| 95 | } |
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| 96 | |
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| 97 | RightHandSide(yTemp2,dydxTemp2); |
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| 98 | |
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| 99 | for( i = 0; i < fNumberOfVariables; i++ ) |
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| 100 | { |
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| 101 | yOut[i] = yIn[i] + h * ( 0.25 * dydx[i] + |
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| 102 | 0.75 * dydxTemp2[i]); |
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| 103 | } |
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| 104 | |
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| 105 | // NormaliseTangentVector( yOut ); |
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| 106 | } |
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