Gabriele Cosmo
179 lines
6.7 KiB
C++
179 lines
6.7 KiB
C++
//
|
|
// ********************************************************************
|
|
// * 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. *
|
|
// ********************************************************************
|
|
//
|
|
// G4HelixMixedStepper
|
|
//
|
|
// Class description:
|
|
//
|
|
// G4HelixMixedStepper split the Method used for Integration in two:
|
|
//
|
|
// If Stepping Angle ( h / R_curve) < pi/3 : use Stepper for small step
|
|
//
|
|
// Else use HelixExplicitEuler Stepper
|
|
//
|
|
// Stepper for the small step is G4ClassicalRK4 by default, but
|
|
// it possible to choose other stepper,like G4CashKarpRK45 or G4RKG3_Stepper,
|
|
// by setting StepperNumber : new HelixMixedStepper(EqRhs,N)
|
|
//
|
|
// N=2 G4SimpleRunge; N=3 G4SimpleHeum;
|
|
// N=4 G4ClassicalRK4;
|
|
// N=6 G4HelixImplicitEuler; N=7 G4HelixSimpleRunge;
|
|
// N=8 G4CashKarpRK45; N=9 G4ExactHelixStepper;
|
|
// N=10 G4RKG3_Stepper; N=13 G4NystromRK4
|
|
// N=23 BogackiShampine23 N=145 TsitourasRK45
|
|
// N=45 BogackiShampine45 N=745 DormandPrince745 (ie DoPri5)
|
|
//
|
|
// For completeness also available are:
|
|
// N=11 G4ExplicitEuler N=12 G4ImplicitEuler; -- Likely poor
|
|
// N=5 G4HelixExplicitEuler (testing only)
|
|
// For recommendations see comments in 'SetupStepper' method.
|
|
//
|
|
// Note: Like other helix steppers, only applicable in pure magnetic field.
|
|
|
|
// Author: Tatiana Nikitina (CERN), 18.05.2007
|
|
// -------------------------------------------------------------------
|
|
#ifndef G4HELIXMIXEDSTEPPER_HH
|
|
#define G4HELIXMIXEDSTEPPER_HH
|
|
|
|
#include "G4MagHelicalStepper.hh"
|
|
|
|
/**
|
|
* @brief G4HelixMixedStepper is a concrete class for particle motion in
|
|
* magnetic field which splits the method used for Integration in two:
|
|
* if the stepping angle ( h / R_curve) is less than pi/3, use a RK stepper
|
|
* for small step, else use G4HelixExplicitEuler stepper.
|
|
* Like other helix steppers, it is only applicable in pure magnetic field.
|
|
*/
|
|
|
|
class G4HelixMixedStepper : public G4MagHelicalStepper
|
|
{
|
|
public:
|
|
|
|
/**
|
|
* Constructor for G4ExactHelixStepper.
|
|
* @param[in] EqRhs Pointer to the standard equation of motion.
|
|
* @param[in] StepperNumber Identified for selecting the stepper type;
|
|
* default (-1) is DormandPrince745.
|
|
* @param[in] Angle_threshold The stepping angle threshold; default (-1)
|
|
* is (1/3)*pi.
|
|
*/
|
|
G4HelixMixedStepper(G4Mag_EqRhs* EqRhs,
|
|
G4int StepperNumber = -1,
|
|
G4double Angle_threshold = -1.0);
|
|
|
|
/**
|
|
* Default Destructor.
|
|
*/
|
|
~G4HelixMixedStepper() override;
|
|
|
|
/**
|
|
* The integration stepper. The stepsize is fixed, with the step size
|
|
* given by 'hstep'. Integrates ODE starting values yInput[0 to 6].
|
|
* Outputs yout[] and its estimated error yerr[].
|
|
* If SteppingAngle = h/R_curve < pi/3, uses default RK stepper else
|
|
* use Helix fast method.
|
|
* @param[in] y Starting values array of integration variables.
|
|
* @param[in] dydx Derivatives array.
|
|
* @param[in] h The given step size.
|
|
* @param[out] yout Integration output.
|
|
* @param[out] yerr The estimated error.
|
|
*/
|
|
void Stepper( const G4double y[],
|
|
const G4double dydx[],
|
|
G4double h,
|
|
G4double yout[],
|
|
G4double yerr[] ) override;
|
|
|
|
/**
|
|
* Same as Stepper() function above, but should perform a 'dump' step
|
|
* without error calculation. Assuming a constant field, the solution is
|
|
* a helix.
|
|
* @param[in] y Starting values array of integration variables.
|
|
* @param[in] Bfld The field vector.
|
|
* @param[in] h The given step size.
|
|
* @param[out] yout Integration output.
|
|
*/
|
|
void DumbStepper( const G4double y[],
|
|
G4ThreeVector Bfld,
|
|
G4double h,
|
|
G4double yout[] ) override;
|
|
|
|
/**
|
|
* Estimates the maximum distance of curved solution and chord.
|
|
*/
|
|
G4double DistChord() const override;
|
|
|
|
/**
|
|
* Sets the verbosity level.
|
|
*/
|
|
inline void SetVerbose (G4int newvalue) { fVerbose = newvalue; }
|
|
|
|
/**
|
|
* Setter and getter for the stepping angle threshold.
|
|
*/
|
|
inline void SetAngleThreshold( G4double val ) { fAngle_threshold = val; }
|
|
inline G4double GetAngleThreshold() { return fAngle_threshold; }
|
|
|
|
/**
|
|
* Returns the order, 4, of integration.
|
|
*/
|
|
inline G4int IntegratorOrder() const override { return 4; }
|
|
|
|
/**
|
|
* Returns the stepper type-ID, "kHelixMixedStepper".
|
|
*/
|
|
inline G4StepperType StepperType() const override { return kHelixMixedStepper; }
|
|
|
|
/**
|
|
* Logger function for the number of calls.
|
|
*/
|
|
void PrintCalls();
|
|
|
|
/**
|
|
* Sets the chosen stepper and equation of motion.
|
|
*/
|
|
G4MagIntegratorStepper* SetupStepper(G4Mag_EqRhs* EqRhs, G4int StepperName);
|
|
|
|
private:
|
|
|
|
/** Mixed Integration RK4 for 'small' steps. */
|
|
G4MagIntegratorStepper* fRK4Stepper = nullptr;
|
|
|
|
/** Int ID of Runge-Kutta stepper. */
|
|
G4int fStepperNumber = -1;
|
|
|
|
/** Threshold angle (in radians ); above it, the Helical stepper is used. */
|
|
G4double fAngle_threshold = -1.0;
|
|
|
|
/** Verbosity level. */
|
|
G4int fVerbose = 0;
|
|
|
|
/** Used for statistic, i.e. how many calls to different steppers. */
|
|
G4int fNumCallsRK4 = 0;
|
|
G4int fNumCallsHelix = 0;
|
|
};
|
|
|
|
#endif
|