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