#include <G4ExactHelixStepper.hh>

Inheritance diagram for G4ExactHelixStepper:

Public Member Functions
G4double	DistChord () const

void	DumbStepper (const G4double y[], G4ThreeVector Bfld, G4double h, G4double yout[])

	G4ExactHelixStepper (const G4ExactHelixStepper &)=delete

	G4ExactHelixStepper (G4Mag_EqRhs *EqRhs)

G4EquationOfMotion *	GetEquationOfMotion ()

const G4EquationOfMotion *	GetEquationOfMotion () const

unsigned long	GetfNoRHSCalls ()

G4int	GetNumberOfStateVariables () const

G4int	GetNumberOfVariables () const

G4int	IntegrationOrder ()

virtual G4int	IntegratorOrder () const

G4bool	IsFSAL () const

void	NormalisePolarizationVector (G4double vec[12])

void	NormaliseTangentVector (G4double vec[6])

G4ExactHelixStepper &	operator= (const G4ExactHelixStepper &)=delete

void	ResetfNORHSCalls ()

void	RightHandSide (const G4double y[], G4double dydx[]) const

void	RightHandSide (const G4double y[], G4double dydx[], G4double field[]) const

void	SetEquationOfMotion (G4EquationOfMotion *newEquation)

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

	~G4ExactHelixStepper ()

Protected Member Functions
void	AdvanceHelix (const G4double yIn[], G4ThreeVector Bfld, G4double h, G4double yHelix[], G4double yHelix2[]=0)

G4double	GetAngCurve () const

G4double	GetCurve () const

G4double	GetInverseCurve (const G4double Momentum, const G4double Bmag)

G4double	GetRadHelix () const

void	LinearStep (const G4double yIn[], G4double h, G4double yHelix[]) const

void	MagFieldEvaluate (const G4double y[], G4ThreeVector &Bfield)

void	SetAngCurve (const G4double Ang)

void	SetCurve (const G4double Curve)

void	SetFSAL (G4bool flag=true)

void	SetIntegrationOrder (G4int order)

void	SetRadHelix (const G4double Rad)

Private Attributes
G4double	fAngCurve = 0.0

G4ThreeVector	fBfieldValue

G4EquationOfMotion *	fEquation_Rhs = nullptr

G4int	fIntegrationOrder = -1

G4bool	fIsFSAL = false

const G4int	fNoIntegrationVariables = 0

unsigned long	fNoRHSCalls = 0UL

const G4int	fNoStateVariables = 0

G4Mag_EqRhs *	fPtrMagEqOfMot = nullptr

G4double	frCurve = 0.0

G4double	frHelix = 0.0

G4ThreeVector	yFinal

G4ThreeVector	yInitial

G4ThreeVector	yMidPoint

Static Private Attributes
static const G4double	fUnitConstant = 0.299792458(GeV/(teslam))

Detailed Description

Definition at line 51 of file G4ExactHelixStepper.hh.

Constructor & Destructor Documentation

◆ G4ExactHelixStepper() [1/2]

G4ExactHelixStepper::G4ExactHelixStepper ( G4Mag_EqRhs * EqRhs )

Definition at line 37 of file G4ExactHelixStepper.cc.

  : G4MagHelicalStepper(EqRhs),
    fBfieldValue(DBL_MAX, DBL_MAX, DBL_MAX)
{
}

◆ ~G4ExactHelixStepper()

G4ExactHelixStepper::~G4ExactHelixStepper ( )

Definition at line 43 of file G4ExactHelixStepper.cc.

44{

45}

◆ G4ExactHelixStepper() [2/2]

G4ExactHelixStepper::G4ExactHelixStepper ( const G4ExactHelixStepper & )

delete

Member Function Documentation

◆ AdvanceHelix()

void G4MagHelicalStepper::AdvanceHelix	(	const G4double	yIn[],
		G4ThreeVector	Bfld,
		G4double	h,
		G4double	yHelix[],
		G4double	yHelix2[] = `0`
	)

protectedinherited

Definition at line 57 of file G4MagHelicalStepper.cc.

{
  // const G4int    nvar = 6;
 
  // OLD  const G4double approc_limit = 0.05;
  // OLD  approc_limit = 0.05 gives max.error=x^5/5!=(0.05)^5/5!=2.6*e-9
  // NEW  approc_limit = 0.005 gives max.error=x^5/5!=2.6*e-14
 
  const G4double approc_limit = 0.005;
  G4ThreeVector  Bnorm, B_x_P, vperp, vpar;
 
  G4double B_d_P;
  G4double B_v_P;
  G4double Theta;
  G4double R_1;
  G4double R_Helix;
  G4double CosT2, SinT2, CosT, SinT;
  G4ThreeVector positionMove, endTangent;
 
  G4double Bmag = Bfld.mag();
  const G4double* pIn = yIn+3;
  G4ThreeVector initVelocity = G4ThreeVector( pIn[0], pIn[1], pIn[2]);
  G4double      velocityVal = initVelocity.mag();
  G4ThreeVector initTangent = (1.0/velocityVal) * initVelocity;
  
  R_1 = GetInverseCurve(velocityVal,Bmag);
 
  // for too small magnetic fields there is no curvature
  // (include momentum here) FIXME
 
  if( (std::fabs(R_1) < 1e-10)||(Bmag<1e-12) )
  {
    LinearStep( yIn, h, yHelix );
 
    // Store and/or calculate parameters for chord distance
 
    SetAngCurve(1.);     
    SetCurve(h);
    SetRadHelix(0.);
  }
  else
  {
    Bnorm = (1.0/Bmag)*Bfld;
 
    // calculate the direction of the force
    
    B_x_P = Bnorm.cross(initTangent);
 
    // parallel and perp vectors
 
    B_d_P = Bnorm.dot(initTangent); // this is the fraction of P parallel to B
 
    vpar = B_d_P * Bnorm;       // the component parallel      to B
    vperp= initTangent - vpar;  // the component perpendicular to B
    
    B_v_P  = std::sqrt( 1 - B_d_P * B_d_P); // Fraction of P perp to B
 
    // calculate  the stepping angle
  
    Theta   = R_1 * h; // * B_v_P;
 
    // Trigonometrix
      
    if( std::fabs(Theta) > approc_limit )
    {
       SinT     = std::sin(Theta);
       CosT     = std::cos(Theta);
    }
    else
    {
      G4double Theta2 = Theta*Theta;
      G4double Theta3 = Theta2 * Theta;
      G4double Theta4 = Theta2 * Theta2;
      SinT     = Theta - 1.0/6.0 * Theta3;
      CosT     = 1 - 0.5 * Theta2 + 1.0/24.0 * Theta4;
    }
 
    // the actual "rotation"
 
    G4double R = 1.0 / R_1;
 
    positionMove  = R * ( SinT * vperp + (1-CosT) * B_x_P) + h * vpar;
    endTangent    = CosT * vperp + SinT * B_x_P + vpar;
 
    // Store the resulting position and tangent
 
    yHelix[0]   = yIn[0] + positionMove.x(); 
    yHelix[1]   = yIn[1] + positionMove.y(); 
    yHelix[2]   = yIn[2] + positionMove.z();
    yHelix[3] = velocityVal * endTangent.x();
    yHelix[4] = velocityVal * endTangent.y();
    yHelix[5] = velocityVal * endTangent.z();
 
    // Store 2*h step Helix if exist
 
    if(yHelix2)
    {
      SinT2     = 2.0 * SinT * CosT;
      CosT2     = 1.0 - 2.0 * SinT * SinT;
      endTangent    = (CosT2 * vperp + SinT2 * B_x_P + vpar);
      positionMove  = R * ( SinT2 * vperp + (1-CosT2) * B_x_P) + h*2 * vpar;
      
      yHelix2[0]   = yIn[0] + positionMove.x(); 
      yHelix2[1]   = yIn[1] + positionMove.y(); 
      yHelix2[2]   = yIn[2] + positionMove.z(); 
      yHelix2[3] = velocityVal * endTangent.x();
      yHelix2[4] = velocityVal * endTangent.y();
      yHelix2[5] = velocityVal * endTangent.z();
    }
 
    // Store and/or calculate parameters for chord distance
 
    G4double ptan=velocityVal*B_v_P;
 
    G4double particleCharge = fPtrMagEqOfMot->FCof() / (eplus*c_light); 
    R_Helix =std::abs( ptan/(fUnitConstant  * particleCharge*Bmag));
       
    SetAngCurve(std::abs(Theta));
    SetCurve(std::abs(R));
    SetRadHelix(R_Helix);
  }
}

References source.hepunit::c_light, CLHEP::Hep3Vector::cross(), CLHEP::Hep3Vector::dot(), eplus, G4Mag_EqRhs::FCof(), G4MagHelicalStepper::fPtrMagEqOfMot, G4MagHelicalStepper::fUnitConstant, G4MagHelicalStepper::GetInverseCurve(), G4MagHelicalStepper::LinearStep(), CLHEP::Hep3Vector::mag(), G4MagHelicalStepper::SetAngCurve(), G4MagHelicalStepper::SetCurve(), G4MagHelicalStepper::SetRadHelix(), CLHEP::Hep3Vector::x(), CLHEP::Hep3Vector::y(), and CLHEP::Hep3Vector::z().

Referenced by DumbStepper(), G4HelixExplicitEuler::DumbStepper(), G4HelixHeum::DumbStepper(), G4HelixImplicitEuler::DumbStepper(), G4HelixMixedStepper::DumbStepper(), G4HelixSimpleRunge::DumbStepper(), G4HelixExplicitEuler::Stepper(), Stepper(), and G4HelixMixedStepper::Stepper().

◆ DistChord()

G4double G4ExactHelixStepper::DistChord ( ) const

virtual

Implements G4MagIntegratorStepper.

Definition at line 95 of file G4ExactHelixStepper.cc.

{
  // Implementation : must check whether h/R >  pi  !!
  //   If( h/R <  pi)   DistChord=h/2*std::tan(Ang_curve/4)
  //   Else             DistChord=R_helix
 
  G4double distChord;
  G4double Ang_curve=GetAngCurve();
 
  if (Ang_curve<=pi)
  {
    distChord=GetRadHelix()*(1-std::cos(0.5*Ang_curve));
  }
  else if(Ang_curve<twopi)
  {
    distChord=GetRadHelix()*(1+std::cos(0.5*(twopi-Ang_curve)));
  }
  else
  {
    distChord=2.*GetRadHelix();  
  }
 
  return distChord;
}   

References G4MagHelicalStepper::GetAngCurve(), G4MagHelicalStepper::GetRadHelix(), pi, and twopi.

◆ DumbStepper()

void G4ExactHelixStepper::DumbStepper	(	const G4double	y[],
		G4ThreeVector	Bfld,
		G4double	h,
		G4double	yout[]
	)

virtual

Implements G4MagHelicalStepper.

Definition at line 77 of file G4ExactHelixStepper.cc.

{
  // Assuming a constant field: solution is a helix
 
  AdvanceHelix(yIn, Bfld, h, yOut);
 
  G4Exception("G4ExactHelixStepper::DumbStepper",
              "GeomField0002", FatalException,
              "Should not be called. Stepper must do all the work." ); 
}  

References G4MagHelicalStepper::AdvanceHelix(), FatalException, and G4Exception().

◆ GetAngCurve()

G4double G4MagHelicalStepper::GetAngCurve ( ) const

inlineprotectedinherited

Referenced by DistChord(), G4HelixExplicitEuler::DistChord(), G4HelixMixedStepper::DistChord(), G4MagHelicalStepper::DistChord(), and G4HelixExplicitEuler::Stepper().

◆ GetCurve()

G4double G4MagHelicalStepper::GetCurve ( ) const

inlineprotectedinherited

◆ GetEquationOfMotion() [1/2]

G4EquationOfMotion * G4MagIntegratorStepper::GetEquationOfMotion ( )

inlineinherited

Referenced by G4MagInt_Driver::GetEquationOfMotion(), G4OldMagIntDriver::GetEquationOfMotion(), G4NystromRK4::GetField(), G4DormandPrince745::GetSpecificEquation(), G4NystromRK4::SetDistanceForConstantField(), G4RKG3_Stepper::StepNoErr(), and G4RKG3_Stepper::Stepper().

◆ GetEquationOfMotion() [2/2]

const G4EquationOfMotion * G4MagIntegratorStepper::GetEquationOfMotion ( ) const

inlineinherited

◆ GetfNoRHSCalls()

unsigned long G4MagIntegratorStepper::GetfNoRHSCalls ( )

inlineinherited

◆ GetInverseCurve()

G4double G4MagHelicalStepper::GetInverseCurve	(	const G4double	Momentum,
		const G4double	Bmag
	)

inlineprotectedinherited

Referenced by G4MagHelicalStepper::AdvanceHelix(), and G4HelixMixedStepper::Stepper().

◆ GetNumberOfStateVariables()

G4int G4MagIntegratorStepper::GetNumberOfStateVariables ( ) const

inlineinherited

Referenced by G4BogackiShampine45::G4BogackiShampine45(), G4CashKarpRKF45::G4CashKarpRKF45(), G4SimpleRunge::G4SimpleRunge(), G4TSimpleRunge< T_Equation, N >::G4TSimpleRunge(), G4TsitourasRK45::G4TsitourasRK45(), G4BogackiShampine23::makeStep(), G4RK547FEq1::makeStep(), G4RK547FEq2::makeStep(), G4RK547FEq3::makeStep(), G4ConstRK4::Stepper(), G4MagErrorStepper::Stepper(), and G4TMagErrorStepper< T_Stepper, T_Equation, N >::Stepper().

◆ GetNumberOfVariables()

G4int G4MagIntegratorStepper::GetNumberOfVariables ( ) const

inlineinherited

Referenced by G4ExplicitEuler::DumbStepper(), G4ImplicitEuler::DumbStepper(), G4ClassicalRK4::DumbStepper(), G4ChordFinder::G4ChordFinder(), G4BogackiShampine45::GetLastDydx(), G4DoLoMcPriRK34::Interpolate(), G4TsitourasRK45::Interpolate(), G4DormandPrince745::Interpolate4thOrder(), G4DormandPrince745::Interpolate5thOrder(), G4DormandPrinceRK56::Interpolate_high(), G4DormandPrinceRK56::Interpolate_low(), G4BogackiShampine45::InterpolateHigh(), G4BogackiShampine23::makeStep(), G4RK547FEq1::makeStep(), G4RK547FEq2::makeStep(), G4RK547FEq3::makeStep(), G4DormandPrinceRK56::SetupInterpolate_high(), G4DormandPrinceRK56::SetupInterpolate_low(), G4DormandPrince745::SetupInterpolation5thOrder(), G4BogackiShampine45::SetupInterpolationHigh(), G4BogackiShampine45::Stepper(), G4CashKarpRKF45::Stepper(), G4DoLoMcPriRK34::Stepper(), G4DormandPrinceRK56::Stepper(), G4DormandPrinceRK78::Stepper(), G4MagErrorStepper::Stepper(), G4TsitourasRK45::Stepper(), and G4DormandPrince745::Stepper().

◆ GetRadHelix()

G4double G4MagHelicalStepper::GetRadHelix ( ) const

inlineprotectedinherited

Referenced by DistChord(), G4HelixExplicitEuler::DistChord(), G4HelixMixedStepper::DistChord(), and G4MagHelicalStepper::DistChord().

◆ IntegrationOrder()

G4int G4MagIntegratorStepper::IntegrationOrder ( )

inlineinherited

◆ IntegratorOrder()

G4int G4ExactHelixStepper::IntegratorOrder ( ) const

virtual

Implements G4MagIntegratorStepper.

Definition at line 123 of file G4ExactHelixStepper.cc.

{
  return 1; 
}

◆ IsFSAL()

G4bool G4MagIntegratorStepper::IsFSAL ( ) const

inlineinherited

◆ LinearStep()

void G4MagHelicalStepper::LinearStep	(	const G4double	yIn[],
		G4double	h,
		G4double	yHelix[]
	)		const

inlineprotectedinherited

Referenced by G4MagHelicalStepper::AdvanceHelix().

◆ MagFieldEvaluate()

void G4MagHelicalStepper::MagFieldEvaluate	(	const G4double	y[],
		G4ThreeVector &	Bfield
	)

inlineprotectedinherited

Referenced by G4HelixHeum::DumbStepper(), G4HelixImplicitEuler::DumbStepper(), G4HelixSimpleRunge::DumbStepper(), G4HelixExplicitEuler::Stepper(), Stepper(), G4HelixMixedStepper::Stepper(), and G4MagHelicalStepper::Stepper().

◆ NormalisePolarizationVector()

void G4MagIntegratorStepper::NormalisePolarizationVector ( G4double vec[12] )

inlineinherited

Referenced by G4SimpleHeum::DumbStepper(), and G4ClassicalRK4::DumbStepper().

◆ NormaliseTangentVector()

void G4MagIntegratorStepper::NormaliseTangentVector ( G4double vec[6] )

inlineinherited

◆ operator=()

G4ExactHelixStepper & G4ExactHelixStepper::operator= ( const G4ExactHelixStepper & )

delete

◆ ResetfNORHSCalls()

void G4MagIntegratorStepper::ResetfNORHSCalls ( )

inlineinherited

◆ RightHandSide() [1/2]

void G4MagIntegratorStepper::RightHandSide	(	const G4double	y[],
		G4double	dydx[]
	)		const

inlineinherited

◆ RightHandSide() [2/2]

void G4MagIntegratorStepper::RightHandSide	(	const G4double	y[],
		G4double	dydx[],
		G4double	field[]
	)		const

inlineinherited

◆ SetAngCurve()

void G4MagHelicalStepper::SetAngCurve ( const G4double Ang )

inlineprotectedinherited

Referenced by G4MagHelicalStepper::AdvanceHelix(), G4HelixExplicitEuler::Stepper(), and G4HelixMixedStepper::Stepper().

◆ SetCurve()

void G4MagHelicalStepper::SetCurve ( const G4double Curve )

inlineprotectedinherited

Referenced by G4MagHelicalStepper::AdvanceHelix(), and G4HelixMixedStepper::Stepper().

◆ SetEquationOfMotion()

void G4MagIntegratorStepper::SetEquationOfMotion ( G4EquationOfMotion * newEquation )

inlineinherited

Referenced by G4MagInt_Driver::SetEquationOfMotion(), and G4OldMagIntDriver::SetEquationOfMotion().

◆ SetFSAL()

void G4MagIntegratorStepper::SetFSAL ( G4bool flag = true )

inlineprotectedinherited

Referenced by G4BogackiShampine23::G4BogackiShampine23().

◆ SetIntegrationOrder()

void G4MagIntegratorStepper::SetIntegrationOrder ( G4int order )

inlineprotectedinherited

Referenced by G4BogackiShampine23::G4BogackiShampine23().

◆ SetRadHelix()

void G4MagHelicalStepper::SetRadHelix ( const G4double Rad )

inlineprotectedinherited

Referenced by G4MagHelicalStepper::AdvanceHelix().

◆ Stepper()

void G4ExactHelixStepper::Stepper	(	const G4double	y[],
		const G4double	dydx[],
		G4double	h,
		G4double	yout[],
		G4double	yerr[]
	)

virtual

Reimplemented from G4MagHelicalStepper.

Definition at line 50 of file G4ExactHelixStepper.cc.

{  
  const G4int nvar = 6;
 
  G4int i;
  G4ThreeVector Bfld_value;
 
  MagFieldEvaluate(yInput, Bfld_value);        
  AdvanceHelix(yInput, Bfld_value, hstep, yOut);
 
  // We are assuming a constant field: helix is exact
  //
  for(i=0; i<nvar; ++i)
  {
    yErr[i] = 0.0 ;
  }
 
  fBfieldValue = Bfld_value;
}

References G4MagHelicalStepper::AdvanceHelix(), fBfieldValue, and G4MagHelicalStepper::MagFieldEvaluate().

Field Documentation

◆ fAngCurve

G4double G4MagHelicalStepper::fAngCurve = 0.0

privateinherited

Definition at line 120 of file G4MagHelicalStepper.hh.

◆ fBfieldValue

G4ThreeVector G4ExactHelixStepper::fBfieldValue

private

Definition at line 83 of file G4ExactHelixStepper.hh.

Referenced by Stepper().

◆ fEquation_Rhs

G4EquationOfMotion* G4MagIntegratorStepper::fEquation_Rhs = nullptr

privateinherited

Definition at line 124 of file G4MagIntegratorStepper.hh.

◆ fIntegrationOrder

G4int G4MagIntegratorStepper::fIntegrationOrder = -1

privateinherited

Definition at line 134 of file G4MagIntegratorStepper.hh.

◆ fIsFSAL

G4bool G4MagIntegratorStepper::fIsFSAL = false

privateinherited

Definition at line 136 of file G4MagIntegratorStepper.hh.

◆ fNoIntegrationVariables

const G4int G4MagIntegratorStepper::fNoIntegrationVariables = 0

privateinherited

Definition at line 125 of file G4MagIntegratorStepper.hh.

◆ fNoRHSCalls

unsigned long G4MagIntegratorStepper::fNoRHSCalls = 0UL

mutableprivateinherited

Definition at line 128 of file G4MagIntegratorStepper.hh.

◆ fNoStateVariables

const G4int G4MagIntegratorStepper::fNoStateVariables = 0

privateinherited

Definition at line 126 of file G4MagIntegratorStepper.hh.

◆ fPtrMagEqOfMot

G4Mag_EqRhs* G4MagHelicalStepper::fPtrMagEqOfMot = nullptr

privateinherited

Definition at line 116 of file G4MagHelicalStepper.hh.

Referenced by G4MagHelicalStepper::AdvanceHelix().

◆ frCurve

G4double G4MagHelicalStepper::frCurve = 0.0

privateinherited

Definition at line 121 of file G4MagHelicalStepper.hh.

◆ frHelix

G4double G4MagHelicalStepper::frHelix = 0.0

privateinherited

Definition at line 122 of file G4MagHelicalStepper.hh.

◆ fUnitConstant

const G4double G4MagHelicalStepper::fUnitConstant = 0.299792458*(GeV/(tesla*m))

staticprivateinherited

Definition at line 113 of file G4MagHelicalStepper.hh.

Referenced by G4MagHelicalStepper::AdvanceHelix().

◆ yFinal

G4ThreeVector G4MagHelicalStepper::yFinal

privateinherited

Definition at line 123 of file G4MagHelicalStepper.hh.

◆ yInitial

G4ThreeVector G4MagHelicalStepper::yInitial

privateinherited

Definition at line 123 of file G4MagHelicalStepper.hh.

◆ yMidPoint

G4ThreeVector G4MagHelicalStepper::yMidPoint

privateinherited

Definition at line 123 of file G4MagHelicalStepper.hh.

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

source/geometry/magneticfield/include/G4ExactHelixStepper.hh
source/geometry/magneticfield/src/G4ExactHelixStepper.cc

Public Member Functions

Protected Member Functions

Private Attributes

Static Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ G4ExactHelixStepper() [1/2]

◆ ~G4ExactHelixStepper()

◆ G4ExactHelixStepper() [2/2]

Member Function Documentation

◆ AdvanceHelix()

◆ DistChord()

◆ DumbStepper()

◆ GetAngCurve()

◆ GetCurve()

◆ GetEquationOfMotion() [1/2]

◆ GetEquationOfMotion() [2/2]

◆ GetfNoRHSCalls()

◆ GetInverseCurve()

◆ GetNumberOfStateVariables()

◆ GetNumberOfVariables()

◆ GetRadHelix()

◆ IntegrationOrder()

◆ IntegratorOrder()

◆ IsFSAL()

◆ LinearStep()

◆ MagFieldEvaluate()

◆ NormalisePolarizationVector()

◆ NormaliseTangentVector()

◆ operator=()

◆ ResetfNORHSCalls()

◆ RightHandSide() [1/2]

◆ RightHandSide() [2/2]

◆ SetAngCurve()

◆ SetCurve()

◆ SetEquationOfMotion()

◆ SetFSAL()

◆ SetIntegrationOrder()

◆ SetRadHelix()

◆ Stepper()

Field Documentation

◆ fAngCurve

◆ fBfieldValue

◆ fEquation_Rhs

◆ fIntegrationOrder

◆ fIsFSAL

◆ fNoIntegrationVariables

◆ fNoRHSCalls

◆ fNoStateVariables

◆ fPtrMagEqOfMot

◆ frCurve

◆ frHelix

◆ fUnitConstant

◆ yFinal

◆ yInitial

◆ yMidPoint