Gabriele Cosmo
129 lines
5.0 KiB
C++
129 lines
5.0 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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// G4MagHelicalStepper
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//
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// Class description:
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//
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// Abstract base class for integrator of particle's equation of motion,
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// used in tracking in space dependent magnetic field
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//
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// It is used for a set of steppers which use the helix as a sort of
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// 'first order' solution.
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// - Most obtain an error by breaking up the step in two
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// - G4ExactHelicalStepper does not provide an error estimate
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// Created: J.Apostolakis, CERN - 05.11.1998
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// --------------------------------------------------------------------
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#ifndef G4MAGHELICALSTEPPER_HH
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#define G4MAGHELICALSTEPPER_HH
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#include <CLHEP/Units/PhysicalConstants.h>
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#include "G4Types.hh"
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#include "G4MagIntegratorStepper.hh"
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#include "G4Mag_EqRhs.hh"
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#include "G4ThreeVector.hh"
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class G4MagHelicalStepper : public G4MagIntegratorStepper
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{
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public: // with description
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G4MagHelicalStepper(G4Mag_EqRhs *EqRhs);
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virtual ~G4MagHelicalStepper();
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G4MagHelicalStepper(const G4MagHelicalStepper&) = delete;
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G4MagHelicalStepper& operator=(const G4MagHelicalStepper&) = delete;
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virtual void Stepper( const G4double y[], // VIRTUAL for ExactHelix
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const G4double dydx[],
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G4double h,
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G4double yout[],
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G4double yerr[] );
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// The stepper for the Runge Kutta integration.
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// The stepsize is fixed, equal to h.
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// Integrates ODE starting values y[0 to 6]
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// Outputs yout[] and its estimated error yerr[].
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virtual void DumbStepper( const G4double y[],
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G4ThreeVector Bfld,
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G4double h,
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G4double yout[] ) = 0;
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// Performs a 'dump' Step without error calculation.
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G4double DistChord()const ;
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// Estimate maximum distance of curved solution and chord ...
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protected: // with description
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inline void LinearStep( const G4double yIn[],
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G4double h,
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G4double yHelix[]) const;
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// A linear Step in regions without magnetic field.
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void AdvanceHelix( const G4double yIn[],
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G4ThreeVector Bfld,
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G4double h,
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G4double yHelix[], G4double yHelix2[] = 0);
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// A first order Step along a helix inside the field.
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inline void MagFieldEvaluate( const G4double y[], G4ThreeVector& Bfield );
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// Evaluate the field at a certain point.
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inline G4double GetInverseCurve( const G4double Momentum,
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const G4double Bmag );
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// Evaluate Inverse of Curvature of Track
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// Store and use the parameters of track :
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// radius of curve, Stepping angle, Radius of projected helix
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inline void SetAngCurve(const G4double Ang);
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inline G4double GetAngCurve()const;
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inline void SetCurve(const G4double Curve);
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inline G4double GetCurve()const;
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inline void SetRadHelix(const G4double Rad);
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inline G4double GetRadHelix()const;
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private:
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static const G4double fUnitConstant;
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// As in G4Mag_EqRhs.hh/cc where it is not used.
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G4Mag_EqRhs* fPtrMagEqOfMot = nullptr;
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// Data stored in order to find the chord
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//
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G4double fAngCurve = 0.0;
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G4double frCurve = 0.0;
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G4double frHelix = 0.0;
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G4ThreeVector yInitial, yMidPoint, yFinal;
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};
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#include "G4MagHelicalStepper.icc"
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#endif
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