G4RKG3_Stepper Class Reference

#include <G4RKG3_Stepper.hh>

Inheritance diagram for G4RKG3_Stepper:

Public Member Functions
	G4RKG3_Stepper (G4Mag_EqRhs *EqRhs)
	~G4RKG3_Stepper ()
void	Stepper (const G4double yIn[], const G4double dydx[], G4double h, G4double yOut[], G4double yErr[])
G4double	DistChord () const
void	StepNoErr (const G4double tIn[8], const G4double dydx[6], G4double Step, G4double tOut[8], G4double B[3])
void	StepWithEst (const G4double tIn[8], const G4double dydx[6], G4double Step, G4double tOut[8], G4double &alpha2, G4double &beta2, const G4double B1[3], G4double B2[3])
G4int	IntegratorOrder () 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 G4RKG3_Stepper.hh.

Constructor & Destructor Documentation

G4RKG3_Stepper()

G4RKG3_Stepper::G4RKG3_Stepper

(

G4Mag_EqRhs *

EqRhs

)

Definition at line 35 of file G4RKG3_Stepper.cc.

  : G4MagIntegratorStepper(EqRhs,6)
{
}

~G4RKG3_Stepper()

G4RKG3_Stepper::~G4RKG3_Stepper

(

)

Definition at line 40 of file G4RKG3_Stepper.cc.

{
}

Member Function Documentation

DistChord()

G4double G4RKG3_Stepper::DistChord ( ) const

virtual

Implements G4MagIntegratorStepper.

Definition at line 196 of file G4RKG3_Stepper.cc.

{
   // Soon: must check whether h/R > 2 pi  !!
   // Method below is good only for < 2 pi
 
   G4double distChord,distLine;
   
   if (fyInitial != fyFinal)
   {
      distLine = G4LineSection::Distline(fyMidPoint,fyInitial,fyFinal);
      distChord = distLine;
   }
   else
   {
      distChord = (fyMidPoint-fyInitial).mag();
   }
 
   return distChord;
}

IntegratorOrder()

G4int G4RKG3_Stepper::IntegratorOrder ( ) const

inlinevirtual

Implements G4MagIntegratorStepper.

Definition at line 88 of file G4RKG3_Stepper.hh.

{ return 4; }

StepNoErr()

void G4RKG3_Stepper::StepNoErr	(	const G4double	tIn[8],
		const G4double	dydx[6],
		G4double	Step,
		G4double	tOut[8],
		G4double	B[3]
	)

Definition at line 130 of file G4RKG3_Stepper.cc.

{ 
  
   // Copy and edit the routine above, to delete alpha2, beta2, ...
   //
   G4double K1[7], K2[7], K3[7], K4[7];
   G4double tTemp[8]={0.0}, yderiv[6]={0.0};
 
   // Need Momentum value to give correct values to the coefficients in
   // equation. Integration on unit velocity, but tIn[3,4,5] is momentum
 
   G4double mom, inverse_mom;
   const G4double c1=0.5, c2=0.125, c3=1./6.;
  
   // Correction for momentum not a velocity
   // Need the protection !!! must be not zero
   //
   mom = std::sqrt(tIn[3]*tIn[3]+tIn[4]*tIn[4]+tIn[5]*tIn[5]); 
   inverse_mom = 1./mom;    
   for(auto i=0; i<3; ++i)
   {
      K1[i] = Step * dydx[i+3]*inverse_mom;
      tTemp[i] = tIn[i] + Step*(c1*tIn[i+3]*inverse_mom + c2*K1[i]) ;
      tTemp[i+3] = tIn[i+3] + c1*K1[i]*mom ;
   }
    
   GetEquationOfMotion()->EvaluateRhsReturnB(tTemp,yderiv,B) ;
      
   for(auto i=0; i<3; ++i)
   {
      K2[i] = Step * yderiv[i+3]*inverse_mom;
      tTemp[i+3] = tIn[i+3] + c1*K2[i]*mom ;
   }
   
   // Given B, calculate yderiv !
   //
   GetEquationOfMotion()->EvaluateRhsGivenB(tTemp,B,yderiv) ;  
 
   for(auto i=0; i<3; ++i)
   {
      K3[i] = Step * yderiv[i+3]*inverse_mom;
      tTemp[i] = tIn[i] + Step*(tIn[i+3]*inverse_mom + c1*K3[i]) ;
      tTemp[i+3] = tIn[i+3] + K3[i]*mom ;
   }
 
   // Calculates y-deriv(atives) & returns B too!
   //
   GetEquationOfMotion()->EvaluateRhsReturnB(tTemp,yderiv,B) ;  
 
   for(auto i=0; i<3; ++i)        // Output trajectory vector
   {
      K4[i] = Step * yderiv[i+3]*inverse_mom;
      tOut[i] = tIn[i] + Step*(tIn[i+3]*inverse_mom+ (K1[i]+K2[i]+K3[i])*c3) ;
      tOut[i+3] = tIn[i+3] + mom*(K1[i] + 2*K2[i] + 2*K3[i] +K4[i])*c3 ;
   }
   tOut[6] = tIn[6];
   tOut[7] = tIn[7];
}

Referenced by Stepper().

Stepper()

void G4RKG3_Stepper::Stepper ( const G4double  yIn[], const G4double  dydx[], G4double  h, G4double  yOut[], G4double  yErr[]  )

virtual

Implements G4MagIntegratorStepper.

Definition at line 44 of file G4RKG3_Stepper.cc.

{
   G4double  B[3];
   G4int nvar = 6 ;
   G4double  by15 = 1. / 15. ; // was  0.066666666 ;
 
   G4double yTemp[8], dydxTemp[6], yIn[8];
 
   // Saving yInput because yInput and yOut can be aliases for same array
   //
   for(G4int i=0; i<nvar; ++i)
   {
     yIn[i]=yInput[i];
   }
   yIn[6] = yInput[6];
   yIn[7] = yInput[7];
   G4double h = Step * 0.5; 
   hStep = Step;
     // Do two half steps
 
   StepNoErr(yIn, dydx,h, yTemp,B) ;
   
   // Store Bfld for DistChord Calculation
   //
   for(auto i=0; i<3; ++i)
   {
     BfldIn[i] = B[i];
   }
   // RightHandSide(yTemp,dydxTemp) ;
 
   GetEquationOfMotion()->EvaluateRhsGivenB(yTemp,B,dydxTemp) ;  
   StepNoErr(yTemp,dydxTemp,h,yOut,B);      
        
   // Store midpoint, chord calculation
                                 
   fyMidPoint = G4ThreeVector(yTemp[0],  yTemp[1],  yTemp[2]); 
 
   // Do a full Step
  //
   h *= 2 ;
   StepNoErr(yIn,dydx,h,yTemp,B); 
   for(G4int i=0; i<nvar; ++i)
   {
      yErr[i] = yOut[i] - yTemp[i] ;
      yOut[i] += yErr[i]*by15 ;          // Provides 5th order of accuracy
   }
 
   // Store values for DistChord method
   //
   fyInitial = G4ThreeVector( yIn[0],   yIn[1],   yIn[2]);
   fpInitial = G4ThreeVector( yIn[3],   yIn[4],   yIn[5]);
   fyFinal   = G4ThreeVector( yOut[0],  yOut[1],  yOut[2]); 
}

StepWithEst()

void G4RKG3_Stepper::StepWithEst	(	const G4double	tIn[8],
		const G4double	dydx[6],
		G4double	Step,
		G4double	tOut[8],
		G4double &	alpha2,
		G4double &	beta2,
		const G4double	B1[3],
		G4double	B2[3]
	)

Definition at line 109 of file G4RKG3_Stepper.cc.

{
  G4Exception("G4RKG3_Stepper::StepWithEst()", "GeomField0001",
              FatalException, "Method no longer used.");
}

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

• G4RKG3_Stepper.hh
• G4RKG3_Stepper.cc