Gabriele Cosmo
77 lines
3.2 KiB
C++
77 lines
3.2 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: G4Mag_UsualEqRhs.cc,v 1.12 2006/06/29 18:24:42 gunter Exp $
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// GEANT4 tag $Name: geant4-09-01 $
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//
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//
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// This is the 'standard' right-hand side for the equation of motion
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// of a charged particle in a magnetic field.
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//
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// Initial version: J. Apostolakis, January 13th, 1997
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//
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// --------------------------------------------------------------------
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#include "G4Mag_UsualEqRhs.hh"
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#include "G4MagneticField.hh"
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G4Mag_UsualEqRhs::G4Mag_UsualEqRhs( G4MagneticField* MagField )
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: G4Mag_EqRhs( MagField ) {}
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G4Mag_UsualEqRhs::~G4Mag_UsualEqRhs() {}
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void
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G4Mag_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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G4double momentum_mag_square = y[3]*y[3] + y[4]*y[4] + y[5]*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[0] = y[3]*inv_momentum_magnitude; // (d/ds)x = Vx/V
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dydx[1] = y[4]*inv_momentum_magnitude; // (d/ds)y = Vy/V
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dydx[2] = y[5]*inv_momentum_magnitude; // (d/ds)z = Vz/V
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dydx[3] = cof*(y[4]*B[2] - y[5]*B[1]) ; // Ax = a*(Vy*Bz - Vz*By)
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dydx[4] = cof*(y[5]*B[0] - y[3]*B[2]) ; // Ay = a*(Vz*Bx - Vx*Bz)
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dydx[5] = cof*(y[3]*B[1] - y[4]*B[0]) ; // Az = a*(Vx*By - Vy*Bx)
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return ;
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}
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void
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G4Mag_UsualEqRhs::
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SetChargeMomentumMass( G4double particleCharge, // in e+ units
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G4double MomentumXc,
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G4double mass)
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{
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fInvCurrentMomentumXc= 1.0 / MomentumXc;
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G4Mag_EqRhs::SetChargeMomentumMass( particleCharge, MomentumXc, mass);
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}
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