[831] | 1 | // |
---|
| 2 | // ******************************************************************** |
---|
| 3 | // * License and Disclaimer * |
---|
| 4 | // * * |
---|
| 5 | // * The Geant4 software is copyright of the Copyright Holders of * |
---|
| 6 | // * the Geant4 Collaboration. It is provided under the terms and * |
---|
| 7 | // * conditions of the Geant4 Software License, included in the file * |
---|
| 8 | // * LICENSE and available at http://cern.ch/geant4/license . These * |
---|
| 9 | // * include a list of copyright holders. * |
---|
| 10 | // * * |
---|
| 11 | // * Neither the authors of this software system, nor their employing * |
---|
| 12 | // * institutes,nor the agencies providing financial support for this * |
---|
| 13 | // * work make any representation or warranty, express or implied, * |
---|
| 14 | // * regarding this software system or assume any liability for its * |
---|
| 15 | // * use. Please see the license in the file LICENSE and URL above * |
---|
| 16 | // * for the full disclaimer and the limitation of liability. * |
---|
| 17 | // * * |
---|
| 18 | // * This code implementation is the result of the scientific and * |
---|
| 19 | // * technical work of the GEANT4 collaboration. * |
---|
| 20 | // * By using, copying, modifying or distributing the software (or * |
---|
| 21 | // * any work based on the software) you agree to acknowledge its * |
---|
| 22 | // * use in resulting scientific publications, and indicate your * |
---|
| 23 | // * acceptance of all terms of the Geant4 Software license. * |
---|
| 24 | // ******************************************************************** |
---|
| 25 | // |
---|
| 26 | // |
---|
| 27 | // $Id: G4SimpleRunge.cc,v 1.10 2006/06/29 18:24:53 gunter Exp $ |
---|
[850] | 28 | // GEANT4 tag $Name: HEAD $ |
---|
[831] | 29 | // |
---|
| 30 | // Simple Runge: |
---|
| 31 | // |
---|
| 32 | // x_1 = x_0 + h * ( dx( t_0+h/2, x_0 + h/2 * dx( t_0, x_0) ) ) |
---|
| 33 | // |
---|
| 34 | // Second order solver. |
---|
| 35 | // Takes the derivative at a position to be assumed at the middle of the |
---|
| 36 | // Step and adds it to the current position. |
---|
| 37 | // |
---|
| 38 | // |
---|
| 39 | // W.Wander <wwc@mit.edu> 12/09/97 |
---|
| 40 | // ------------------------------------------------------------------- |
---|
| 41 | |
---|
| 42 | #include "G4SimpleRunge.hh" |
---|
| 43 | #include "G4ThreeVector.hh" |
---|
| 44 | |
---|
| 45 | //////////////////////////////////////////////////////////////// |
---|
| 46 | // |
---|
| 47 | // Constructor |
---|
| 48 | |
---|
| 49 | G4SimpleRunge::G4SimpleRunge(G4EquationOfMotion* EqRhs, G4int numberOfVariables) |
---|
| 50 | : G4MagErrorStepper(EqRhs, numberOfVariables), |
---|
| 51 | fNumberOfVariables(numberOfVariables) |
---|
| 52 | { |
---|
| 53 | |
---|
| 54 | unsigned int noVariables= std::max(numberOfVariables, |
---|
| 55 | GetNumberOfStateVariables()); |
---|
| 56 | // To deal with Time >= 7+1 |
---|
| 57 | dydxTemp = new G4double[noVariables] ; |
---|
| 58 | yTemp = new G4double[noVariables] ; |
---|
| 59 | } |
---|
| 60 | |
---|
| 61 | |
---|
| 62 | ///////////////////////////////////////////////////////////////// |
---|
| 63 | // |
---|
| 64 | // Destructor |
---|
| 65 | |
---|
| 66 | G4SimpleRunge::~G4SimpleRunge() |
---|
| 67 | { |
---|
| 68 | delete[] dydxTemp; |
---|
| 69 | delete[] yTemp; |
---|
| 70 | } |
---|
| 71 | |
---|
| 72 | ////////////////////////////////////////////////////////////////// |
---|
| 73 | // |
---|
| 74 | // |
---|
| 75 | |
---|
| 76 | void |
---|
| 77 | G4SimpleRunge::DumbStepper( const G4double yIn[], |
---|
| 78 | const G4double dydx[], |
---|
| 79 | G4double h, |
---|
| 80 | G4double yOut[]) |
---|
| 81 | { |
---|
| 82 | // Initialise time to t0, needed when it is not updated by the integration. |
---|
| 83 | yTemp[7] = yOut[7] = yIn[7]; // Better to set it to NaN; // TODO |
---|
| 84 | |
---|
| 85 | G4int i; |
---|
| 86 | |
---|
| 87 | for( i = 0; i < fNumberOfVariables; i++ ) |
---|
| 88 | { |
---|
| 89 | yTemp[i] = yIn[i] + 0.5 * h*dydx[i] ; |
---|
| 90 | } |
---|
| 91 | |
---|
| 92 | RightHandSide(yTemp,dydxTemp); |
---|
| 93 | |
---|
| 94 | for( i = 0; i < fNumberOfVariables; i++ ) |
---|
| 95 | { |
---|
| 96 | yOut[i] = yIn[i] + h * ( dydxTemp[i] ); |
---|
| 97 | } |
---|
| 98 | } |
---|