G4MagErrorStepper Class Reference

#include <G4MagErrorStepper.hh>

Inheritance diagram for G4MagErrorStepper:

Public Member Functions
	G4MagErrorStepper (G4EquationOfMotion *EqRhs, G4int numberOfVariables, G4int numStateVariables=12)
virtual	~G4MagErrorStepper ()
	G4MagErrorStepper (const G4MagErrorStepper &)=delete
G4MagErrorStepper &	operator= (const G4MagErrorStepper &)=delete
void	Stepper (const G4double y[], const G4double dydx[], G4double h, G4double yout[], G4double yerr[])
virtual void	DumbStepper (const G4double y[], const G4double dydx[], G4double h, G4double yout[])=0
G4double	DistChord () const
Public Member Functions inherited from G4MagIntegratorStepper
	G4MagIntegratorStepper (G4EquationOfMotion *Equation, G4int numIntegrationVariables, G4int numStateVariables=12, G4bool isFSAL=false)
virtual	~G4MagIntegratorStepper ()=default
	G4MagIntegratorStepper (const G4MagIntegratorStepper &)=delete
G4MagIntegratorStepper &	operator= (const G4MagIntegratorStepper &)=delete
virtual void	Stepper (const G4double y[], const G4double dydx[], G4double h, G4double yout[], G4double yerr[])=0
virtual G4double	DistChord () const =0
void	NormaliseTangentVector (G4double vec[6])
void	NormalisePolarizationVector (G4double vec[12])
void	RightHandSide (const G4double y[], G4double dydx[]) const
void	RightHandSide (const G4double y[], G4double dydx[], G4double field[]) const
G4int	GetNumberOfVariables () const
G4int	GetNumberOfStateVariables () const
virtual G4int	IntegratorOrder () const =0
G4int	IntegrationOrder ()
G4EquationOfMotion *	GetEquationOfMotion ()
const G4EquationOfMotion *	GetEquationOfMotion () const
void	SetEquationOfMotion (G4EquationOfMotion *newEquation)
unsigned long	GetfNoRHSCalls ()
void	ResetfNORHSCalls ()
G4bool	IsFSAL () const

Additional Inherited Members
Protected Member Functions inherited from G4MagIntegratorStepper
void	SetIntegrationOrder (G4int order)
void	SetFSAL (G4bool flag=true)

Detailed Description

Definition at line 43 of file G4MagErrorStepper.hh.

Constructor & Destructor Documentation

G4MagErrorStepper() [1/2]

G4MagErrorStepper::G4MagErrorStepper	(	G4EquationOfMotion *	EqRhs,
		G4int	numberOfVariables,
		G4int	numStateVariables = 12
	)

~G4MagErrorStepper()

G4MagErrorStepper::~G4MagErrorStepper ( )

virtual

Definition at line 34 of file G4MagErrorStepper.cc.

{
   delete [] yMiddle;
   delete [] dydxMid;
   delete [] yInitial;
   delete [] yOneStep;
}

G4MagErrorStepper() [2/2]

G4MagErrorStepper::G4MagErrorStepper ( const G4MagErrorStepper &  )

delete

Member Function Documentation

DistChord()

G4double G4MagErrorStepper::DistChord ( ) const

virtual

Implements G4MagIntegratorStepper.

Definition at line 100 of file G4MagErrorStepper.cc.

{
  // Estimate the maximum distance from the curve to the chord
  //
  // We estimate this using the distance of the midpoint to 
  // chord (the line between 
  // 
  // Method below is good only for angle deviations < 2 pi, 
  // This restriction should not a problem for the Runge cutta methods, 
  // which generally cannot integrate accurately for large angle deviations.
 
  G4double distLine, distChord; 
 
  if (fInitialPoint != fFinalPoint)
  {
     distLine = G4LineSection::Distline(fMidPoint, fInitialPoint, fFinalPoint);
       // This is a class method that gives distance of Mid 
       // from the Chord between the Initial and Final points.
 
     distChord = distLine;
  }
  else
  {
     distChord = (fMidPoint-fInitialPoint).mag();
  }
 
  return distChord;
}

DumbStepper()

virtual void G4MagErrorStepper::DumbStepper ( const G4double  y[], const G4double  dydx[], G4double  h, G4double  yout[]  )

pure virtual

Implemented in G4ExplicitEuler, G4ImplicitEuler, G4SimpleHeum, G4SimpleRunge, G4ClassicalRK4, and G4ConstRK4.

Referenced by Stepper().

operator=()

G4MagErrorStepper & G4MagErrorStepper::operator= ( const G4MagErrorStepper &  )

delete

Stepper()

void G4MagErrorStepper::Stepper ( const G4double  y[], const G4double  dydx[], G4double  h, G4double  yout[], G4double  yerr[]  )

virtual

Implements G4MagIntegratorStepper.

Definition at line 42 of file G4MagErrorStepper.cc.

{  
   const G4int nvar = GetNumberOfVariables();
   const G4int maxvar = GetNumberOfStateVariables();
 
   // correction for Richardson Extrapolation.
   //
   G4double  correction = 1. / ( (1 << IntegratorOrder()) -1 );
   
   //  Saving yInput because yInput and yOutput can be aliases for same array
   //
   for(G4int i=0; i<nvar; ++i)
   {
     yInitial[i]=yInput[i];
   }
   yInitial[7] = yInput[7]; // Copy the time in case...even if not really needed
   yMiddle[7] = yInput[7];  // Copy the time from initial value 
   yOneStep[7] = yInput[7]; // As it contributes to final value of yOutput ?
   // yOutput[7] = yInput[7];  // -> dumb stepper does it too for RK4
 
   for(G4int i=nvar; i<maxvar; ++i)
   {
     yOutput[i]=yInput[i];
   }
   // yError[7] = 0.0;         
 
   G4double halfStep = hstep * 0.5; 
 
   // Do two half steps
   //
   DumbStepper  (yInitial,  dydx,   halfStep, yMiddle);
   RightHandSide(yMiddle, dydxMid);    
   DumbStepper  (yMiddle, dydxMid, halfStep, yOutput); 
 
   // Store midpoint, chord calculation
   //
   fMidPoint = G4ThreeVector( yMiddle[0],  yMiddle[1],  yMiddle[2]); 
 
   // Do a full Step
   //
   DumbStepper(yInitial, dydx, hstep, yOneStep);
   for(G4int i=0; i<nvar; ++i)
   {
      yError [i] = yOutput[i] - yOneStep[i] ;
      yOutput[i] += yError[i]*correction ;
        // Provides accuracy increased by 1 order via Richardson Extrapolation  
   }
 
   fInitialPoint = G4ThreeVector( yInitial[0], yInitial[1], yInitial[2]); 
   fFinalPoint   = G4ThreeVector( yOutput[0],  yOutput[1],  yOutput[2]); 
 
   return;
}

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The documentation for this class was generated from the following files:

• G4MagErrorStepper.hh
• G4MagErrorStepper.cc