Gabriele Cosmo
374 lines
14 KiB
C++
374 lines
14 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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// G4MagInt_Driver
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//
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// Class description:
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//
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// Provides a driver that talks to the Integrator Stepper, and insures that
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// the error is within acceptable bounds.
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// Author: Vladimir Grichine (CERN), 07.10.1996 - Created
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// W.Wander (MIT), 28.01.1998 - Added ability for low order integrators
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// --------------------------------------------------------------------
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#ifndef G4MAGINT_DRIVER_HH
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#define G4MAGINT_DRIVER_HH
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#include "G4VIntegrationDriver.hh"
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#include "G4MagIntegratorStepper.hh"
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#include "G4ChordFinderDelegate.hh"
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/**
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* @brief G4MagInt_Driver provides a driver that talks to the Integrator
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* Stepper and insures that the error is within acceptable bounds.
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*/
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class G4MagInt_Driver : public G4VIntegrationDriver,
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public G4ChordFinderDelegate<G4MagInt_Driver>
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{
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public:
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/**
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* Constructor for G4MagInt_Driver.
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* @param[in] hminimum The minumum allowed step.
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* @param[in] pItsStepper Pointer to the integrator stepper.
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* @param[in] numberOfComponents The number of integration variables.
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* @param[in] statisticsVerbosity Flag for verbosity.
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*/
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G4MagInt_Driver(G4double hminimum,
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G4MagIntegratorStepper* pItsStepper,
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G4int numberOfComponents = 6,
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G4int statisticsVerbosity = 0);
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/**
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* Destructor. Provides statistics if verbosity level is greater than 1.
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*/
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~G4MagInt_Driver() override;
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/**
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* Copy constructor and assignment operator not allowed.
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*/
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G4MagInt_Driver(const G4MagInt_Driver&) = delete;
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G4MagInt_Driver& operator=(const G4MagInt_Driver&) = delete;
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/**
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* Computes the step to take, based on chord limits.
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* @param[in,out] track The current track in field.
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* @param[in] stepMax Proposed maximum step length.
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* @param[in] epsStep Requested accuracy, y_err/hstep.
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* @param[in] chordDistance Maximum sagitta distance.
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* @returns The length of step taken.
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*/
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inline G4double AdvanceChordLimited(G4FieldTrack& track,
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G4double stepMax,
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G4double epsStep,
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G4double chordDistance) override;
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/**
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* Dispatch interface method for initialisation/reset of driver.
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*/
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inline void OnStartTracking() override;
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/**
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* Dispatch interface method for computing step. Does nothing here.
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*/
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inline void OnComputeStep(const G4FieldTrack* = nullptr) override {}
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/**
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* The driver implements re-integration, so returns true.
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*/
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G4bool DoesReIntegrate() const override { return true; }
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/**
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* Advances integration accurately by relative accuracy better than 'eps'.
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* @param[in,out] y_current The current track in field.
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* @param[in] hstep Proposed step length.
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* @param[in] eps Requested accuracy, y_err/hstep.
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* @param[in] hinitial Initial minimum integration step.
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* @returns true if integration succeeds.
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*/
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G4bool AccurateAdvance(G4FieldTrack& y_current,
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G4double hstep,
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G4double eps, // Requested y_err/hstep
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G4double hinitial = 0.0) override;
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/**
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* Attempts one integration step, and returns estimated error 'dyerr'.
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* It does not ensure accuracy.
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* @param[in,out] y_val The current track in field.
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* @param[in] dydx dydx array.
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* @param[in] hstep Proposed step length.
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* @param[out] dchord_step Estimated sagitta distance.
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* @param[out] dyerr Estimated error.
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* @returns true if integration succeeds.
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*/
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G4bool QuickAdvance(G4FieldTrack& y_val, // In/Out
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const G4double dydx[],
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G4double hstep,
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G4double& dchord_step,
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G4double& dyerr) override;
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/**
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* Writes out to stream the parameters/state of the driver.
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*/
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void StreamInfo( std::ostream& os ) const override;
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/**
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* Attempts one integration step, and returns estimated error 'dyerr'.
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* It does not ensure accuracy.
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* @param[in,out] y_posvel The current track in field.
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* @param[in] dydx dydx array.
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* @param[in] hstep Proposed step length.
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* @param[out] dchord_step Estimated sagitta distance.
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* @param[out] dyerr_pos_sq Estimated error in position.
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* @param[out] dyerr_mom_rel_sq Estimated error in momentum
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* (normalised: Delta_Integration(p^2)/(p^2)).
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* @returns true if integration succeeds.
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*/
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G4bool QuickAdvance(G4FieldTrack& y_posvel, // In/Out
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const G4double dydx[],
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G4double hstep, // In
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G4double& dchord_step,
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G4double& dyerr_pos_sq,
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G4double& dyerr_mom_rel_sq );
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/**
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* Accessors.
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*/
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inline G4double GetHmin() const;
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inline G4double Hmin() const; // Obsolete
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inline G4double GetSafety() const;
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inline G4double GetPshrnk() const;
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inline G4double GetPgrow() const;
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inline G4double GetErrcon() const;
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void GetDerivatives(const G4FieldTrack& y_curr, // INput
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G4double dydx[]) const override; // OUTput
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void GetDerivatives(const G4FieldTrack& track,
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G4double dydx[],
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G4double field[]) const override;
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/**
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* Getter and setter for the equation of motion.
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*/
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G4EquationOfMotion* GetEquationOfMotion() override;
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void SetEquationOfMotion(G4EquationOfMotion* equation) override;
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/**
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* Sets a new stepper 'pItsStepper' for this driver. Then it calls
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* ResetParameters() to update its parameters accordingly.
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*/
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void RenewStepperAndAdjust(G4MagIntegratorStepper* pItsStepper) override;
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/**
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* Resets the qarameters according to the new provided safety value.
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* i) sets the exponents (pgrow & pshrnk), using the current order;
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* ii) sets the safety and calculates "errcon" according to the above values.
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*/
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inline void ReSetParameters(G4double new_safety = 0.9);
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/**
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* Modifiers. When setting safety or pgrow, errcon will be set
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* to a compatible value.
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*/
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inline void SetSafety(G4double valS);
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inline void SetPshrnk(G4double valPs);
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inline void SetPgrow (G4double valPg);
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inline void SetErrcon(G4double valEc);
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inline G4double ComputeAndSetErrcon();
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/**
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* Accessors for the integrator stepper.
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*/
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const G4MagIntegratorStepper* GetStepper() const override;
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G4MagIntegratorStepper* GetStepper() override;
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/**
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* Takes one Step that is as large as possible while satisfying the
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* accuracy criterion of: yerr < eps * |y_end-y_start|.
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* @param[in,out] ystart The current track state, y.
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* @param[in] dydx The derivatives array.
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* @param[in,out] x Step start, x.
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* @param[in] htry Step to attempt.
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* @param[in] eps The relative accuracy.
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* @param[out] hdid Step achieved.
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* @param[out] hnext Proposed next step.
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* @returns true if integration succeeds.
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*/
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void OneGoodStep(G4double ystart[], // Like old RKF45step()
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const G4double dydx[],
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G4double& x,
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G4double htry,
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G4double eps,
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G4double& hdid,
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G4double& hnext ) ;
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/**
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* Takes the last step's normalised error and calculates a step size
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* for the next step. Does it limit the next step's size within a factor
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* of the current?
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* -- DOES NOT limit for very bad steps
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* -- DOES limit for very good (x5).
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*/
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G4double ComputeNewStepSize(G4double errMaxNorm, // normalised
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G4double hstepCurrent) override;
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/**
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* Taking the last step's normalised error, calculates a step size for
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* the next step. Does not limit the next step's size within a factor of
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* the current one when *reducing* the size, i.e. for badly failing steps.
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*/
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G4double ComputeNewStepSize_WithoutReductionLimit(G4double errMaxNorm,
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G4double hstepCurrent);
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/**
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* Taking the last step's normalised error, calculates a step size for
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* the next step. Limits the next step's size within a range around the
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* current one.
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*/
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G4double ComputeNewStepSize_WithinLimits(G4double errMaxNorm, // normalised
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G4double hstepCurrent);
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/**
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* Modifier and accessor for the maximum number of steps that can be taken
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* for the integration of a single segment, i.e. a single call to
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* AccurateAdvance().
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*/
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inline G4int GetMaxNoSteps() const;
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inline void SetMaxNoSteps(G4int val);
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/**
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* More modifiers and accessors.
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*/
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inline void SetHmin(G4double newval);
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void SetVerboseLevel(G4int newLevel) override;
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G4int GetVerboseLevel() const override;
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inline G4double GetSmallestFraction() const;
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void SetSmallestFraction( G4double val );
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protected:
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/**
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* Loggers, issuing warnings for undesirable situations.
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*/
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void WarnSmallStepSize(G4double hnext, G4double hstep,
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G4double h, G4double xDone,
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G4int noSteps);
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void WarnTooManyStep(G4double x1start, G4double x2end, G4double xCurrent);
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void WarnEndPointTooFar(G4double endPointDist,
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G4double hStepSize ,
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G4double epsilonRelative,
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G4int debugFlag);
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/**
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* Loggers for verbosity printouts.
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*/
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void PrintStatus(const G4double* StartArr,
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G4double xstart,
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const G4double* CurrentArr,
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G4double xcurrent,
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G4double requestStep,
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G4int subStepNo);
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void PrintStatus(const G4FieldTrack& StartFT,
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const G4FieldTrack& CurrentFT,
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G4double requestStep,
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G4int subStepNo);
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void PrintStat_Aux(const G4FieldTrack& aFieldTrack,
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G4double requestStep,
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G4double actualStep,
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G4int subStepNo,
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G4double subStepSize,
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G4double dotVelocities);
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/**
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* Reports on the number of steps, maximum errors etc.
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*/
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void PrintStatisticsReport();
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#ifdef QUICK_ADV_TWO
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G4bool QuickAdvance( G4double yarrin[], // In
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const G4double dydx[],
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G4double hstep,
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G4double yarrout[], // Out
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G4double& dchord_step, // Out
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G4double& dyerr ); // in length
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#endif
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private:
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// ---------------------------------------------------------------
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// INVARIANTS
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/** Minimum Step allowed in a Step (in absolute units). */
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G4double fMinimumStep = 0.0;
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/** Smallest fraction of (existing) curve length, in relative units.
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Below this fraction the current step will be the last. */
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G4double fSmallestFraction = 1.0e-12; // Expected range 1e-12 to 5e-15
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/** Variables in integration. */
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const G4int fNoIntegrationVariables = 0;
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/** Minimum number for FieldTrack. */
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const G4int fMinNoVars = 12;
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/** Full number of variable. */
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const G4int fNoVars = 0;
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/** Default maximum number of steps is Base divided by the order of Stepper. */
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G4int fMaxNoSteps;
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G4int fMaxStepBase = 250; // was 5000
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/** Parameters used to grow and shrink trial stepsize. */
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G4double safety;
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G4double pshrnk; // exponent for shrinking
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G4double pgrow; // exponent for growth
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G4double errcon;
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G4int fStatisticsVerboseLevel = 0;
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// ---------------------------------------------------------------
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// DEPENDENT Objects
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G4MagIntegratorStepper* pIntStepper = nullptr;
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// ---------------------------------------------------------------
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// STATE
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/** Step Statistics. */
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unsigned long fNoTotalSteps=0, fNoBadSteps=0;
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unsigned long fNoSmallSteps=0, fNoInitialSmallSteps=0, fNoCalls=0;
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G4double fDyerr_max=0.0, fDyerr_mx2=0.0;
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G4double fDyerrPos_smTot=0.0, fDyerrPos_lgTot=0.0, fDyerrVel_lgTot=0.0;
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G4double fSumH_sm=0.0, fSumH_lg=0.0;
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/** Could be varied during tracking - to help identify issues. */
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G4int fVerboseLevel = 0; // Verbosity level for printing (debug, ..)
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using ChordFinderDelegate = G4ChordFinderDelegate<G4MagInt_Driver>;
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};
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#include "G4MagIntegratorDriver.icc"
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#endif
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