Directory: source/geometry/magneticfield/include
File Name: G4MagIntegratorDriver.hh
Provides a driver that talks to the Integrator Stepper, and insures that the error is within acceptable bounds.
G4bool AccurateAdvance(G4FieldTrack& y_current,
G4double hstep,
G4double eps, // Requested y_err/hstep
G4double hinitial=0.0); // Suggested 1st interval
// Above drivers for integrator (Runge-Kutta) with stepsize control.
// Integrates ODE starting values y_current
// from current s (s=s0) to s=s0+h with accuracy eps.
// On output ystart is replaced by value at end of interval.
// The concept is similar to the odeint routine from NRC p.721-722.
G4bool QuickAdvance( G4FieldTrack& y_val, // INOUT
const G4double dydx[],
G4double hstep, // IN
G4double& dchord_step,
G4double& dyerr ) ;
// QuickAdvance just tries one Step - it does not ensure accuracy.
G4bool QuickAdvance( G4FieldTrack& y_posvel, // INOUT
const G4double dydx[],
G4double hstep, // IN
G4double& dchord_step,
G4double& dyerr_pos_sq,
G4double& dyerr_mom_rel_sq ) ;
// New QuickAdvance that also just tries one Step
// (so also does not ensure accuracy)
// but does return the errors in position and
// momentum (normalised: Delta_Integration(p^2)/(p^2) )
G4MagInt_Driver( G4double hminimum,
G4MagIntegratorStepper *pItsStepper,
G4int numberOfComponents=6,
G4int statisticsVerbosity=1);
~G4MagInt_Driver();
// Constructor, destructor.
inline G4double GetHmin() const;
inline G4double Hmin() const; // Obsolete
inline G4double GetSafety() const;
inline G4double GetPshrnk() const;
inline G4double GetPgrow() const;
inline G4double GetErrcon() const;
inline void GetDerivatives( const G4FieldTrack &y_curr, // const, INput
G4double dydx[] ); // OUTput
// Accessors.
inline void RenewStepperAndAdjust(G4MagIntegratorStepper *pItsStepper);
// Sets a new stepper pItsStepper for this driver. Then it calls
// ReSetParameters to reset its parameters accordingly.
inline void ReSetParameters(G4double new_safety= 0.9 );
// i) sets the exponents (pgrow & pshrnk),
// using the current Stepper's order,
// ii) sets the safety
// ii) calculates "errcon" according to the above values.
inline void SetSafety(G4double valS);
inline void SetPshrnk(G4double valPs);
inline void SetPgrow (G4double valPg);
inline void SetErrcon(G4double valEc);
// When setting safety or pgrow, errcon will be set to a
// compatible value.
inline G4double ComputeAndSetErrcon();
inline void SetChargeMomentumMass( G4double particleCharge,
G4double MomentumXc,
G4double Mass );
// Change them in Equation. particleCharge is in e+ units.
inline const G4MagIntegratorStepper* GetStepper() const;
void OneGoodStep( G4double ystart[], // Like old RKF45step()
const G4double dydx[],
G4double& x,
G4double htry,
G4double eps, // memb variables ?
G4double& hdid,
G4double& hnext ) ;
// This takes one Step that is as large as possible while
// satisfying the accuracy criterion of:
// yerr < eps * |y_end-y_start|
G4double ComputeNewStepSize( G4double errMaxNorm, // normalised error
G4double hstepCurrent); // current step size
// Taking the last step's normalised error, calculate
// a step size for the next step.
// Do not limit the next step's size within a factor of the
// current one.
G4double ComputeNewStepSize_WithinLimits(
G4double errMaxNorm, // normalised error
G4double hstepCurrent); // current step size
// Taking the last step's normalised error, calculate
// a step size for the next step.
// Limit the next step's size within a range around the current one.
inline G4int GetMaxNoSteps() const;
inline 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).