Gabriele Cosmo
142 lines
5.2 KiB
C++
142 lines
5.2 KiB
C++
// ********************************************************************
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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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// G4RK547FEq3
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//
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// Class description:
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//
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// An implementation of the 7 stage embedded Runge-Kutta 4,5 pair (RK547FEq3)
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// from the paper:
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// D. J. Higham and G. Hall,
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// "Embedded Runge-Kutta formulae with stable equilibrium states",
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// J. Comput. Appl. Math., vol. 29, no. 1, pp. 25-33, 1990.
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// Author: Dmitry Sorokin (CERN, Google Summer of Code 2017), 02.11.2017
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// Supervision: John Apostolakis (CERN)
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// --------------------------------------------------------------------
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#ifndef G4RK547FEq3_HH
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#define G4RK547FEq3_HH
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#include "G4MagIntegratorStepper.hh"
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#include "G4FieldTrack.hh"
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/**
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* @brief G4RK547FEq3 is an implementation of the 7 stage embedded
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* Runge-Kutta 4,5 pair.
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*/
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class G4RK547FEq3 : public G4MagIntegratorStepper
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{
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public:
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/**
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* Constructor for G4RK547FEq1.
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* @param[in] EqRhs Pointer to the provided equation of motion.
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* @param[in] integrationVariables The number of integration variables.
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*/
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G4RK547FEq3(G4EquationOfMotion* EqRhs,
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G4int integrationVariables = 6);
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/**
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* Default Destructor.
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*/
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~G4RK547FEq3() override = default;
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/**
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* Copy constructor and assignment operator not allowed.
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*/
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G4RK547FEq3(const G4RK547FEq3&) = delete;
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G4RK547FEq3& operator = (const G4RK547FEq3&) = 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 'hstep'.
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* Integrates ODE starting values yInput[0 to 6].
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* Outputs yOutput[] and its estimated error yError[].
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* @param[in] yInput Starting values array of integration variables.
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* @param[in] dydx Derivatives array.
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* @param[in] hstep The given step size.
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* @param[out] yOutput Integration output.
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* @param[out] yError The estimated error.
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*/
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void Stepper( const G4double yInput[],
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const G4double dydx[],
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G4double hstep,
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G4double yOutput[],
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G4double yError[] ) override;
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/**
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* Same as the Stepper() function above, with dydx also in ouput.
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* @param[in] yInput Starting values array of integration variables.
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* @param[in] dydx Derivatives array.
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* @param[in] hstep The given step size.
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* @param[out] yOutput Integration output.
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* @param[out] yError The estimated error.
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* @param[out] dydxOutput dydx in output.
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*/
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void Stepper( const G4double yInput[],
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const G4double dydx[],
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G4double hstep,
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G4double yOutput[],
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G4double yError[],
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G4double dydxOutput[] );
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/**
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* Returns the distance from chord line.
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*/
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G4double DistChord() const override;
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/**
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* Returns the order, 4, of integration.
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*/
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G4int IntegratorOrder() const override { return 4; }
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/**
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* Returns the stepper type-ID, "kRK547FEq3".
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*/
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G4StepperType StepperType() const override { return kRK547FEq3; }
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private:
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/**
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* Utility method used in Stepper() for computing the actual step.
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*/
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void makeStep( const G4double yInput[],
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const G4double dydx[],
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const G4double hstep,
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G4double yOutput[],
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G4double* dydxOutput = nullptr,
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G4double* yError = nullptr) const;
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private:
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G4double fyIn[G4FieldTrack::ncompSVEC],
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fdydx[G4FieldTrack::ncompSVEC],
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fyOut[G4FieldTrack::ncompSVEC],
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fdydxOut[G4FieldTrack::ncompSVEC];
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G4double fhstep = -1.0;
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};
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#endif
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