Gabriele Cosmo
160 lines
5.4 KiB
C++
160 lines
5.4 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. *
|
|
// ********************************************************************
|
|
//
|
|
// G4RKIntegrationDriver
|
|
//
|
|
// Class description:
|
|
//
|
|
// Driver class which controls the integration error of a
|
|
// Runge-Kutta stepper
|
|
|
|
// Author: Dmitry Sorokin (CERN, Google Summer of Code 2017), 20.10.2017
|
|
// --------------------------------------------------------------------
|
|
#ifndef G4RKINTEGRATIONDRIVER_HH
|
|
#define G4RKINTEGRATIONDRIVER_HH
|
|
|
|
#include "G4VIntegrationDriver.hh"
|
|
|
|
/**
|
|
* @brief G4RKIntegrationDriver is a templated driver class which controls the
|
|
* integration error of a Runge-Kutta stepper.
|
|
*/
|
|
|
|
template <class T>
|
|
class G4RKIntegrationDriver : public G4VIntegrationDriver
|
|
{
|
|
public:
|
|
|
|
/**
|
|
* Constructor for G4RKIntegrationDriver.
|
|
* @param[in] stepper Pointer to the stepper algorithm.
|
|
*/
|
|
G4RKIntegrationDriver(T* stepper);
|
|
|
|
/**
|
|
* Copy constructor and assignment operator not allowed.
|
|
*/
|
|
G4RKIntegrationDriver(const G4RKIntegrationDriver&) = delete;
|
|
G4RKIntegrationDriver& operator=(const G4RKIntegrationDriver&) = delete;
|
|
|
|
/**
|
|
* Accessors for derivatives.
|
|
*/
|
|
void GetDerivatives(const G4FieldTrack& track,
|
|
G4double dydx[]) const override;
|
|
void GetDerivatives(const G4FieldTrack& track,
|
|
G4double dydx[],
|
|
G4double field[]) const override;
|
|
|
|
/**
|
|
* Taking the last step's normalised error, it calculates a step size for
|
|
* the next step; it limits the next step's size within a factor of the
|
|
* current one.
|
|
*/
|
|
G4double ComputeNewStepSize(G4double errMaxNorm, // normalised error
|
|
G4double hstepCurrent) final;
|
|
|
|
/**
|
|
* Getter and setter for the equation of motion.
|
|
*/
|
|
G4EquationOfMotion* GetEquationOfMotion() override;
|
|
void SetEquationOfMotion(G4EquationOfMotion* equation) override;
|
|
|
|
/**
|
|
* Accessors for the stepper.
|
|
*/
|
|
const T* GetStepper() const override;
|
|
T* GetStepper() override;
|
|
|
|
/**
|
|
* Writes out to stream the parameters/state of the driver.
|
|
*/
|
|
void StreamInfo( std::ostream& os ) const override;
|
|
|
|
/**
|
|
* Accessors.
|
|
*/
|
|
G4double GetSafety() const;
|
|
G4double GetPshrnk() const;
|
|
G4double GetPgrow() const;
|
|
|
|
void RenewStepperAndAdjust(G4MagIntegratorStepper* stepper) override;
|
|
|
|
void ReSetParameters(G4double safety = 0.9);
|
|
void SetSafety(G4double valS);
|
|
// i) sets the exponents (pgrow & pshrnk),
|
|
// using the current Stepper's order,
|
|
// ii) sets the safety
|
|
|
|
G4int GetMaxNoSteps() const;
|
|
void SetMaxNoSteps(G4int val);
|
|
// Modify and Get the Maximum number of Steps that can be
|
|
// taken for the integration of a single segment -
|
|
// (ie a single call to AccurateAdvance).
|
|
|
|
G4double GetSmallestFraction() const;
|
|
void SetSmallestFraction(G4double val);
|
|
|
|
protected:
|
|
|
|
/**
|
|
* Utility methods to control step size.
|
|
*/
|
|
G4double ShrinkStepSize(G4double h, G4double error) const;
|
|
G4double GrowStepSize(G4double h, G4double error) const;
|
|
G4double ShrinkStepSize2(G4double h, G4double error2) const;
|
|
G4double GrowStepSize2(G4double h, G4double error2) const;
|
|
void UpdateErrorConstraints();
|
|
|
|
private:
|
|
|
|
/**
|
|
* Sets the stepper according to the provided one.
|
|
*/
|
|
inline void RenewStepperAndAdjustImpl(T* stepper);
|
|
|
|
private:
|
|
|
|
G4int fMaxNoSteps;
|
|
|
|
/** The (default) max number of steps is Base divided by the order of Stepper. */
|
|
G4int fMaxStepBase;
|
|
|
|
/** Parameters used to grow and shrink trial stepsize. */
|
|
G4double safety;
|
|
G4double pshrnk; // exponent for shrinking
|
|
G4double pgrow; // exponent for growth
|
|
|
|
/** Maximum error values for shrinking / growing (optimisation). */
|
|
G4double errorConstraintShrink;
|
|
G4double errorConstraintGrow;
|
|
|
|
T* pIntStepper = nullptr;
|
|
};
|
|
|
|
#include "G4RKIntegrationDriver.icc"
|
|
|
|
#endif
|