Gabriele Cosmo
72 lines
3.0 KiB
C++
72 lines
3.0 KiB
C++
//
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// ********************************************************************
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// * License and Disclaimer *
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// * *
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// * The Geant4 software is copyright of the Copyright Holders of *
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// * the Geant4 Collaboration. It is provided under the terms and *
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// * conditions of the Geant4 Software License, included in the file *
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// * LICENSE and available at http://cern.ch/geant4/license . These *
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// * include a list of copyright holders. *
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// * *
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// * Neither the authors of this software system, nor their employing *
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// * institutes,nor the agencies providing financial support for this *
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// * work make any representation or warranty, express or implied, *
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// * regarding this software system or assume any liability for its *
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// * use. Please see the license in the file LICENSE and URL above *
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// * for the full disclaimer and the limitation of liability. *
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// * *
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// * This code implementation is the result of the scientific and *
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// * technical work of the GEANT4 collaboration. *
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// * By using, copying, modifying or distributing the software (or *
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// * any work based on the software) you agree to acknowledge its *
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// * use in resulting scientific publications, and indicate your *
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// * acceptance of all terms of the Geant4 Software license. *
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// ********************************************************************
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//
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//
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// $Id: G4ErrorMag_UsualEqRhs.cc,v 1.1 2007/05/16 12:54:02 gcosmo Exp $
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// GEANT4 tag $Name: geant4-09-02 $
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//
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//
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// --------------------------------------------------------------------
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// GEANT 4 class implementation file
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// --------------------------------------------------------------------
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#include "G4ErrorMag_UsualEqRhs.hh"
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#include "G4ErrorPropagatorData.hh"
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//---------------------------------------------------------------------
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G4ErrorMag_UsualEqRhs::G4ErrorMag_UsualEqRhs( G4MagneticField* MagField )
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: G4Mag_UsualEqRhs( MagField )
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{
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}
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G4ErrorMag_UsualEqRhs::~G4ErrorMag_UsualEqRhs()
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{
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}
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//---------------------------------------------------------------------
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void
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G4ErrorMag_UsualEqRhs::EvaluateRhsGivenB( const G4double y[],
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const G4double B[3],
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G4double dydx[] ) const
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{
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G4Mag_UsualEqRhs::EvaluateRhsGivenB(y, B, dydx );
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if(G4ErrorPropagatorData::GetErrorPropagatorData()->GetMode()
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== G4ErrorMode_PropBackwards)
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{
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G4double momentum_mag_square = sqr(y[3]) + sqr(y[4]) + sqr(y[5]);
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G4double inv_momentum_magnitude = 1.0 / std::sqrt( momentum_mag_square );
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G4double cof = FCof()*inv_momentum_magnitude;
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dydx[3] = cof*(y[4]*(-B[2]) - y[5]*(-B[1])) ;
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dydx[4] = cof*(y[5]*(-B[0]) - y[3]*(-B[2])) ;
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dydx[5] = cof*(y[3]*(-B[1]) - y[4]*(-B[0])) ;
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}
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return;
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}
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