00001 // 00002 // ******************************************************************** 00003 // * License and Disclaimer * 00004 // * * 00005 // * The Geant4 software is copyright of the Copyright Holders of * 00006 // * the Geant4 Collaboration. It is provided under the terms and * 00007 // * conditions of the Geant4 Software License, included in the file * 00008 // * LICENSE and available at http://cern.ch/geant4/license . These * 00009 // * include a list of copyright holders. * 00010 // * * 00011 // * Neither the authors of this software system, nor their employing * 00012 // * institutes,nor the agencies providing financial support for this * 00013 // * work make any representation or warranty, express or implied, * 00014 // * regarding this software system or assume any liability for its * 00015 // * use. Please see the license in the file LICENSE and URL above * 00016 // * for the full disclaimer and the limitation of liability. * 00017 // * * 00018 // * This code implementation is the result of the scientific and * 00019 // * technical work of the GEANT4 collaboration. * 00020 // * By using, copying, modifying or distributing the software (or * 00021 // * any work based on the software) you agree to acknowledge its * 00022 // * use in resulting scientific publications, and indicate your * 00023 // * acceptance of all terms of the Geant4 Software license. * 00024 // ******************************************************************** 00025 // 00026 // 00027 // $Id: G4ExplicitEuler.cc 69786 2013-05-15 09:38:51Z gcosmo $ 00028 // 00029 // 00030 // Explicit Euler: x_1 = x_0 + h * dx_0 00031 // 00032 // most simple approach for solving linear differential equations. 00033 // Take the current derivative and add it to the current position. 00034 // 00035 // W.Wander <wwc@mit.edu> 12/09/97 00036 // ------------------------------------------------------------------- 00037 00038 #include "G4ExplicitEuler.hh" 00039 #include "G4ThreeVector.hh" 00040 00042 // 00043 // Constructor 00044 00045 G4ExplicitEuler::G4ExplicitEuler(G4EquationOfMotion* EqRhs, 00046 G4int numberOfVariables) 00047 : G4MagErrorStepper(EqRhs, numberOfVariables) 00048 { 00049 } 00050 00051 00053 // 00054 // Destructor 00055 00056 G4ExplicitEuler::~G4ExplicitEuler() 00057 { 00058 } 00059 00060 00062 // 00063 // 00064 00065 void 00066 G4ExplicitEuler::DumbStepper( const G4double yIn[], 00067 const G4double dydx[], 00068 G4double h, 00069 G4double yOut[] ) 00070 { 00071 const G4int numberOfVariables= GetNumberOfVariables(); 00072 00073 // Initialise time to t0, needed when it is not updated by the integration. 00074 // yOut[7] = yIn[7]; // Better to set it to NaN; // TODO 00075 00076 G4int i; 00077 00078 for(i=0;i< numberOfVariables;i++) 00079 { 00080 yOut[i] = yIn[i] + h*dydx[i] ; // 1st and only Step 00081 } 00082 00083 return ; 00084 }