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// $Id: G4ChordFinder.hh,v 1.21 2008/10/29 14:17:42 gcosmo Exp $
// GEANT4 tag $Name: geant4-09-02 $
//
//
// Class G4ChordFinder
//
// class description:
//
// A class that provides RK integration of motion ODE (as does g4magtr)
// and also has a method that returns an Approximate point on the curve
// near to a (chord) point.
// History:
// - 25.02.97 - John Apostolakis - Design and implementation
// -------------------------------------------------------------------
#ifndef G4CHORDFINDER_HH
#define G4CHORDFINDER_HH
#include "G4MagIntegratorDriver.hh"
#include "G4FieldTrack.hh"
class G4MagneticField;
class G4ChordFinder
{
public: // with description
G4ChordFinder( G4MagInt_Driver* pIntegrationDriver );
G4ChordFinder( G4MagneticField* itsMagField,
G4double stepMinimum = 1.0e-2 * mm,
G4MagIntegratorStepper* pItsStepper = 0 );
// A constructor that creates defaults for all "children" classes.
virtual ~G4ChordFinder();
G4double AdvanceChordLimited( G4FieldTrack& yCurrent,
G4double stepInitial,
G4double epsStep_Relative,
const G4ThreeVector latestSafetyOrigin,
G4double lasestSafetyRadius);
// Uses ODE solver's driver to find the endpoint that satisfies
// the chord criterion: that d_chord < delta_chord
// -> Returns Length of Step taken.
G4FieldTrack ApproxCurvePointS( const G4FieldTrack& curveAPointVelocity,
const G4FieldTrack& curveBPointVelocity,
const G4FieldTrack& ApproxCurveV,
const G4ThreeVector& currentEPoint,
const G4ThreeVector& currentFPoint,
const G4ThreeVector& PointG,
G4bool first, G4double epsStep);
G4FieldTrack ApproxCurvePointV( const G4FieldTrack& curveAPointVelocity,
const G4FieldTrack& curveBPointVelocity,
const G4ThreeVector& currentEPoint,
G4double epsStep);
inline G4double InvParabolic( const G4double xa, const G4double ya,
const G4double xb, const G4double yb,
const G4double xc, const G4double yc );
inline G4double GetDeltaChord() const;
inline void SetDeltaChord(G4double newval);
inline void SetChargeMomentumMass(G4double pCharge, // in e+ units
G4double pMomentum,
G4double pMass );
// Function to inform integration driver of charge, speed.
inline void SetIntegrationDriver(G4MagInt_Driver* IntegrationDriver);
inline G4MagInt_Driver* GetIntegrationDriver();
// Access and set Driver.
inline void ResetStepEstimate();
// Clear internal state (last step estimate)
inline G4int GetNoCalls();
inline G4int GetNoTrials(); // Total number of trials
inline G4int GetNoMaxTrials(); // Maximum # of trials for one call
// Get statistics about number of calls & trials in FindNextChord
virtual void PrintStatistics();
// A report with the above -- and possibly other stats
inline G4int SetVerbose( G4int newvalue=1);
// Set verbosity and return old value
void SetFractions_Last_Next( G4double fractLast= 0.90,
G4double fractNext= 0.95 );
// Parameters for performance ... change with great care
inline void SetFirstFraction(G4double fractFirst);
// Parameter for performance ... change with great care
public: // without description
void TestChordPrint( G4int noTrials,
G4int lastStepTrial,
G4double dChordStep,
G4double nextStepTrial );
// Printing for monitoring ...
inline G4double GetFirstFraction(); // Originally 0.999
inline G4double GetFractionLast(); // Originally 1.000
inline G4double GetFractionNextEstimate(); // Originally 0.980
inline G4double GetMultipleRadius(); // No original value
// Parameters for adapting performance ... use with great care
protected: // .........................................................
inline void AccumulateStatistics( G4int noTrials );
// Accumulate the basic statistics
// - other specialised ones must be kept by derived classes
inline G4bool AcceptableMissDist(G4double dChordStep) const;
G4double NewStep( G4double stepTrialOld,
G4double dChordStep, // Current dchord estimate
G4double& stepEstimate_Unconstrained ) ;
virtual G4double FindNextChord( const G4FieldTrack& yStart,
G4double stepMax,
G4FieldTrack& yEnd,
G4double& dyErr, // Error of endpoint
G4double epsStep,
G4double* pNextStepForAccuracy, // = 0,
const G4ThreeVector latestSafetyOrigin,
G4double latestSafetyRadius
);
void PrintDchordTrial(G4int noTrials,
G4double stepTrial,
G4double oldStepTrial,
G4double dChordStep);
inline G4double GetLastStepEstimateUnc();
inline void SetLastStepEstimateUnc( G4double stepEst );
private: // ............................................................
G4ChordFinder(const G4ChordFinder&);
G4ChordFinder& operator=(const G4ChordFinder&);
// Private copy constructor and assignment operator.
private: // ............................................................
// G4int nOK, nBAD;
G4MagInt_Driver* fIntgrDriver;
const G4double fDefaultDeltaChord; // SET in G4ChordFinder.cc = 0.25 mm
G4double fDeltaChord; // Maximum miss distance
G4double fLastStepEstimate_Unconstrained;
// State information for efficiency
// Variables used in construction/destruction
G4bool fAllocatedStepper;
G4EquationOfMotion* fEquation;
G4MagIntegratorStepper* fDriversStepper;
// Parameters
G4double fFirstFraction, fFractionLast, fFractionNextEstimate;
G4double fMultipleRadius;
// For Statistics
// -- G4int fNoTrials, fNoCalls;
G4int fTotalNoTrials_FNC, fNoCalls_FNC, fmaxTrials_FNC; // fnoTimesMaxTrFNC;
G4int fStatsVerbose; // if > 0, print Statistics in destructor
};
// Inline function implementation:
#include "G4ChordFinder.icc"
#endif // G4CHORDFINDER_HH