Gabriele Cosmo
219 lines
7.6 KiB
C++
219 lines
7.6 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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// G4MagIntegratorStepper
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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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// A Stepper must integrate over NumberOfVariables elements,
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// and also copy (from input to output) any of NoStateVariables
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// not included in the NumberOfVariables.
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//
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// So it is expected that NoStateVariables >= NumberOfVariables
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// Author: John Apostolakis (CERN), 15.01.1997
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// --------------------------------------------------------------------
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#ifndef G4MAGINTEGRATORSTEPPER_HH
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#define G4MAGINTEGRATORSTEPPER_HH
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#include "G4Types.hh"
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#include "G4EquationOfMotion.hh"
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#include "G4FieldParameters.hh"
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#include "G4VIntegrationDriver.hh"
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#include "G4IntegrationDriver.hh"
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class G4VIntegrationDriver;
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/**
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* @brief G4MagIntegratorStepper is an abstract base class for integrator
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* of particle's equation of motion, used in tracking in space dependent
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* magnetic field.
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*/
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class G4MagIntegratorStepper
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{
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public:
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/**
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* Constructor for G4MagIntegratorStepper.
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* @param[in] Equation Pointer to the provided equation of motion.
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* @param[in] numIntegrationVariables The number of integration variables.
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* @param[in] numStateVariables The number of state variables.
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* @param[in] isFSAL Flag to indicate if it is an FSAL (First Same As Last)
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* type driver.
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*/
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G4MagIntegratorStepper(G4EquationOfMotion* Equation,
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G4int numIntegrationVariables,
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G4int numStateVariables = 12,
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G4bool isFSAL = false );
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/**
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* Default virtual Destructor.
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*/
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virtual ~G4MagIntegratorStepper() = default;
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/**
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* Copy constructor and assignment operator not allowed.
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*/
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G4MagIntegratorStepper(const G4MagIntegratorStepper&) = delete;
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G4MagIntegratorStepper& operator=(const G4MagIntegratorStepper&) = delete;
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/**
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* The stepper for the Runge Kutta integration.
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* The stepsize is fixed, with the step size given by '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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* @param[in] y Starting values array of integration variables.
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* @param[in] dydx Derivatives array.
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* @param[in] h The given step size.
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* @param[out] yout Integration output.
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* @param[out] yerr The estimated error.
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*/
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virtual void Stepper( const G4double y[],
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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[] ) = 0;
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/**
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* Estimates the maximum distance of a chord from the true path
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* over the segment last integrated.
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*/
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virtual G4double DistChord() const = 0;
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/**
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* Simple utility function to (re)normalise 'unit velocity' vector.
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*/
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inline void NormaliseTangentVector( G4double vec[6] );
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/**
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* Simple utility function to (re)normalise 'unit spin' vector.
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*/
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inline void NormalisePolarizationVector( G4double vec[12] );
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/**
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* Utility method to supply the standard Evaluation of the
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* Right Hand side of the associated equation.
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*/
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inline void RightHandSide( const G4double y[], G4double dydx[] ) const;
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/**
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* Calculates 'dydx' and 'field' at point 'y'.
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*/
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inline void RightHandSide( const G4double y[],
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G4double dydx[],
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G4double field[] ) const;
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/**
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* Returns the number of variables that the stepper will integrate over.
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*/
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inline G4int GetNumberOfVariables() const;
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/**
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* Returns the number of variables of state variables (>= above, integration).
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*/
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inline G4int GetNumberOfStateVariables() const;
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/**
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* Returns the order of the integrator, i.e. its error behaviour is of
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* the order O(h^order).
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*/
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virtual G4int IntegratorOrder() const = 0;
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/**
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* Returns the stepper type ID ('kUserStepper').
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* This function should be overriden in derived classes.
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*/
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virtual G4StepperType StepperType() const { return kUserStepper; }
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/**
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* Replacement method - using new data member.
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*/
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inline G4int IntegrationOrder();
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/**
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* Methods returning the pointer to the associated equation of motion.
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* As some steppers (e.g. RKG3) require other methods of Eq_Rhs this
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* function allows for access to them.
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*/
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inline G4EquationOfMotion* GetEquationOfMotion();
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inline const G4EquationOfMotion* GetEquationOfMotion() const;
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/**
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* Setter for the equation of motion.
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*/
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inline void SetEquationOfMotion(G4EquationOfMotion* newEquation);
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/**
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* Methods for counting/resetting the number of calls to RHS method(s).
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*/
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inline unsigned long GetfNoRHSCalls();
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inline void ResetfNORHSCalls();
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/**
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* Returns true if the stepper is of FSAL (First Same As Last) type.
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*/
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inline G4bool IsFSAL() const;
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/**
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* Returns true if the stepper is of QSS (Quantum State Simulation) type.
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*/
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inline G4bool isQSS() const;
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inline void SetIsQSS(G4bool val);
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protected:
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/**
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* Setters for the integration order and FSAL type.
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*/
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inline void SetIntegrationOrder(G4int order);
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inline void SetFSAL(G4bool flag = true);
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private:
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G4EquationOfMotion* fEquation_Rhs = nullptr;
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const G4int fNoIntegrationVariables = 0; // Variables in integration
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const G4int fNoStateVariables = 0; // Number required for FieldTrack
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/** Counter for calls to RHS method. */
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mutable unsigned long fNoRHSCalls = 0UL;
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// Parameters of a RK method -- must be shared by all steppers of a type
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// -- Invariants for a class
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G4int fIntegrationOrder = -1; // must be set by stepper !!!
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// All ClassicalRK4 steppers are 4th order
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G4bool fIsFSAL = false;
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// Depends on RK method & implementation
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G4bool fIsQSS = false;
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};
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#include "G4MagIntegratorStepper.icc"
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#endif
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