// // ******************************************************************** // * 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. * // ******************************************************************** // // G4InterpolationDriver // // Class description: // // Driver class which uses Runge-Kutta stepper with interpolation property // to integrate track with error control // Author: Dmitry Sorokin (CERN), 26.09.2018 // -------------------------------------------------------------------- #ifndef G4INTERPOLATION_DRIVER_HH #define G4INTERPOLATION_DRIVER_HH #include "G4FieldUtils.hh" #include "G4RKIntegrationDriver.hh" #include "globals.hh" #include #include /** * @brief G4InterpolationDriver is a templated driver class which uses * Runge-Kutta stepper with interpolation property to integrate track with * error control. */ template class G4InterpolationDriver : public G4RKIntegrationDriver { public: /** * Constructor for G4IntegrationDriver. * @param[in] hminimum Minimum allowed step. * @param[in] stepper Pointer to the stepper algorithm. * @param[in] numberOfComponents The number of integration variables, * if not matching stepper's number of variables, issue exception. * @param[in] statisticsVerbosity Verbosity level. */ G4InterpolationDriver(G4double hminimum, T* stepper, G4int numberOfComponents = 6, G4int statisticsVerbosity = 0); /** * Destructor. Provides statistics if verbosity level is greater than zero. */ ~G4InterpolationDriver() override; /** * Copy constructor and assignment operator not allowed. */ G4InterpolationDriver(const G4InterpolationDriver&) = delete; const G4InterpolationDriver& operator=(const G4InterpolationDriver&) = delete; /** * Computes the step to take, based on chord limits. * @param[in,out] track The current track in field. * @param[in] hstep Proposed step length. * @param[in] eps Requested accuracy, y_err/hstep. * @param[in] chordDistance Maximum sagitta distance. * @returns The length of step taken. */ G4double AdvanceChordLimited(G4FieldTrack& track, G4double hstep, G4double eps, G4double chordDistance) override; /** * Dispatch interface method for initialisation/reset of driver. */ void OnStartTracking() override; /** * Dispatch interface method for computing step. Does nothing here. */ void OnComputeStep(const G4FieldTrack* /*track*/ = nullptr) override; /** * The driver does not implement re-integration. Returns false. */ G4bool DoesReIntegrate() const override { return false; } /** * Advances integration accurately by relative accuracy better than 'eps'. * On output the track is replaced by the value at the end of interval. * @param[in,out] track The current track in field. * @param[in] hstep Proposed step length. * @param[in] eps Requested accuracy, y_err/hstep. * @param[in] hinitial Initial minimum integration step. * @returns true if integration succeeds. */ G4bool AccurateAdvance(G4FieldTrack& track, G4double hstep, G4double eps, // Requested y_err/hstep G4double hinitial = 0) override; /** * Setter and getter for verbosity. */ void SetVerboseLevel(G4int level) override; G4int GetVerboseLevel() const override; /** * Writes out to stream the parameters/state of the driver. */ void StreamInfo(std::ostream& os) const override; protected: struct InterpStepper { std::unique_ptr stepper; G4double begin; G4double end; G4double inverseLength; }; using StepperIterator = typename std::vector::iterator; using ConstStepperIterator = typename std::vector::const_iterator; /** * Takes one Step that is as large as possible while satisfying the * accuracy criterion. * @param[in] it Stepper iterator. * @param[in,out] y The current track state, y. * @param[in] dydx dydx array. * @param[in,out] hstep Step to attempt. * @param[in] eps The relative accuracy. * @param[in] curveLength Step start, x. * @param[in,out] track Pointer to the Field track. Not used. * @returns The step achieved. */ virtual G4double OneGoodStep(StepperIterator it, field_utils::State& y, field_utils::State& dydx, G4double& hstep, G4double eps, G4double curveLength, G4FieldTrack* track = nullptr); /** * Track interpolation. * @param[in] curveLength Step start, x. * @param[in,out] y The current track state, y. */ void Interpolate(G4double curveLength, field_utils::State& y) const; /** * Wrapper method for interpolation. */ void InterpolateImpl(G4double curveLength, ConstStepperIterator it, field_utils::State& y) const; /** * Methods for calculation of chord step and distance. */ G4double DistChord(const field_utils::State& yBegin, G4double curveLengthBegin, const field_utils::State& yEnd, G4double curveLengthEnd) const; G4double FindNextChord(const field_utils::State& yBegin, G4double curveLengthBegin, field_utils::State& yEnd, G4double curveLengthEnd, G4double dChord, G4double maxChordDistance); G4double CalcChordStep(G4double stepTrialOld, G4double dChordStep, G4double fDeltaChord); /** * Internal methods for printing/checking the state. */ void PrintState() const; void CheckState() const; /** * Increments number of trials and calls. */ void AccumulateStatistics(G4int noTrials); protected: std::vector fSteppers; StepperIterator fLastStepper; G4bool fKeepLastStepper = false; /** Memory of last good step size for integration. */ G4double fhnext = DBL_MAX; /** Minimum Step allowed (in units of length). */ G4double fMinimumStep; G4double fChordStepEstimate = DBL_MAX; const G4double fFractionNextEstimate = 0.98; // Constant const G4double fSmallestCurveFraction = 0.01; // Constant G4int fVerboseLevel; // Parameter field_utils::State fdydx; G4bool fFirstStep = true; G4int fMaxTrials = 100; // Constant G4int fTotalStepsForTrack = 0; /** Statistics. */ G4int fTotalNoTrials = 0; G4int fNoCalls = 0; G4int fmaxTrials = 0; using Base = G4RKIntegrationDriver; }; #include "G4InterpolationDriver.icc" #endif