Gabriele Cosmo
123 lines
4.8 KiB
Plaintext
123 lines
4.8 KiB
Plaintext
//
|
|
// ********************************************************************
|
|
// * License and Disclaimer *
|
|
// * *
|
|
// * The Geant4 software is copyright of the Copyright Holders of *
|
|
// * the Geant4 Collaboration. It is provided under the terms and *
|
|
// * conditions of the Geant4 Software License, included in the file *
|
|
// * LICENSE and available at http://cern.ch/geant4/license . These *
|
|
// * include a list of copyright holders. *
|
|
// * *
|
|
// * Neither the authors of this software system, nor their employing *
|
|
// * institutes,nor the agencies providing financial support for this *
|
|
// * work make any representation or warranty, express or implied, *
|
|
// * regarding this software system or assume any liability for its *
|
|
// * use. Please see the license in the file LICENSE and URL above *
|
|
// * for the full disclaimer and the limitation of liability. *
|
|
// * *
|
|
// * This code implementation is the result of the scientific and *
|
|
// * technical work of the GEANT4 collaboration. *
|
|
// * By using, copying, modifying or distributing the software (or *
|
|
// * any work based on the software) you agree to acknowledge its *
|
|
// * use in resulting scientific publications, and indicate your *
|
|
// * acceptance of all terms of the Geant4 Software license. *
|
|
// ********************************************************************
|
|
//
|
|
//
|
|
//
|
|
//
|
|
// class G4BFieldIntegrationDriver
|
|
//
|
|
// Class description:
|
|
//
|
|
// Specialized integration driver for pure magnetic field
|
|
|
|
// History:
|
|
// - Created. D.Sorokin
|
|
// --------------------------------------------------------------------
|
|
|
|
|
|
#include "globals.hh"
|
|
#include "G4GeometryTolerance.hh"
|
|
#include "G4FieldTrack.hh"
|
|
#include "G4FieldUtils.hh"
|
|
|
|
namespace internal {
|
|
|
|
G4Mag_EqRhs* toMagneticEquation(G4EquationOfMotion* equation)
|
|
{
|
|
auto e = dynamic_cast<G4Mag_EqRhs*>(equation);
|
|
|
|
if (!e) {
|
|
G4Exception("G4BFieldIntegrationDriver::G4BFieldIntegrationDriver",
|
|
"GeomField0003", FatalErrorInArgument,
|
|
"Works only with G4Mag_EqRhs");
|
|
}
|
|
|
|
return e;
|
|
}
|
|
|
|
} // internal
|
|
|
|
|
|
template <class T>
|
|
G4BFieldIntegrationDriver<T>::G4BFieldIntegrationDriver(G4double hminimum,
|
|
T* pStepper,
|
|
G4int numComponents,
|
|
G4int statisticsVerbose)
|
|
: G4IntegrationDriver<T>(hminimum, pStepper, numComponents, statisticsVerbose)
|
|
, fallbackThreshold(pi / 3.)
|
|
, fequation(internal::toMagneticEquation(pStepper->GetEquationOfMotion()))
|
|
, fallbackStepper(fequation)
|
|
{
|
|
}
|
|
|
|
template <class T>
|
|
bool G4BFieldIntegrationDriver<T>::QuickAdvance(G4FieldTrack& fieldTrack,
|
|
const G4double dydx[],
|
|
G4double hstep,
|
|
G4double inverseCurvatureRadius,
|
|
G4double& dchord_step,
|
|
G4double& dyerr)
|
|
{
|
|
if (hstep * inverseCurvatureRadius < fallbackThreshold) {
|
|
return G4IntegrationDriver<T>::QuickAdvance(
|
|
fieldTrack, dydx, hstep, inverseCurvatureRadius, dchord_step, dyerr);
|
|
}
|
|
|
|
G4IntegrationDriver<T>::IncrementQuickAdvanceCalls();
|
|
|
|
G4double yError[G4FieldTrack::ncompSVEC],
|
|
yIn[G4FieldTrack::ncompSVEC],
|
|
yOut[G4FieldTrack::ncompSVEC];
|
|
|
|
fieldTrack.DumpToArray(yIn);
|
|
|
|
fallbackStepper.Stepper(yIn, dydx, hstep, yOut, yError);
|
|
dchord_step = fallbackStepper.DistChord();
|
|
dyerr = field_utils::absoluteError(yOut, yError, hstep);
|
|
|
|
fieldTrack.LoadFromArray(yOut, fallbackStepper.GetNumberOfVariables());
|
|
fieldTrack.SetCurveLength(fieldTrack.GetCurveLength() + hstep);
|
|
|
|
return true;
|
|
}
|
|
|
|
template <class T>
|
|
void G4BFieldIntegrationDriver<T>::SetEquationOfMotion(G4EquationOfMotion* equation)
|
|
{
|
|
G4IntegrationDriver<T>::SetEquationOfMotion(equation);
|
|
fequation = internal::toMagneticEquation(equation);
|
|
}
|
|
|
|
template <class T>
|
|
G4double G4BFieldIntegrationDriver<T>::GetInverseCurvatureRadius(const G4FieldTrack& track,
|
|
G4double field[]) const
|
|
{
|
|
const G4double Bmag = std::sqrt(field[0] * field[0] + field[1] * field[1] + field[2] * field[2]);
|
|
const G4double momentum = track.GetMomentum().mag();
|
|
const G4double particleCharge = fequation->FCof() / (CLHEP::eplus * CLHEP::c_light);
|
|
|
|
return std::abs(field_utils::inverseCurvatureRadius(particleCharge, momentum, Bmag));
|
|
}
|