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: G4HelixSimpleRunge.cc 69786 2013-05-15 09:38:51Z gcosmo $ 00028 // 00029 // 00030 // Simple Runge: 00031 // x_1 = x_0 + h * ( dx( t_0+h/2, x_0 + h/2 * dx( t_0, x_0) ) ) 00032 // 00033 // Second order solver. 00034 // Take the derivative at a position to be assumed at the middle of the 00035 // Step and add it to the current position. 00036 // 00037 // W.Wander <wwc@mit.edu> 12/09/97 00038 // ------------------------------------------------------------------------- 00039 00040 #include "G4HelixSimpleRunge.hh" 00041 #include "G4ThreeVector.hh" 00042 00043 void 00044 G4HelixSimpleRunge::DumbStepper( const G4double yIn[], 00045 G4ThreeVector Bfld, 00046 G4double h, 00047 G4double yOut[]) 00048 { 00049 const G4int nvar = 6 ; 00050 G4double yTemp[nvar]; // , yAdd[nvar]; 00051 G4ThreeVector Bfld_midpoint; 00052 00053 AdvanceHelix( yIn, Bfld, 0.5 * h, yTemp); 00054 00055 // now obtain the new field value at the new point 00056 MagFieldEvaluate(yTemp, Bfld_midpoint); 00057 00058 AdvanceHelix( yIn, Bfld_midpoint, h, yOut); 00059 00060 // NormaliseTangentVector( yOut ); 00061 }