G4BogackiShampine23 Class Reference

#include <G4BogackiShampine23.hh>

Inheritance diagram for G4BogackiShampine23:

Collaboration diagram for G4BogackiShampine23:

Public Member Functions
	G4BogackiShampine23 (G4EquationOfMotion *EqRhs, G4int numberOfVariables=6, G4bool primary=true)
	~G4BogackiShampine23 ()
void	Stepper (const G4double y[], const G4double dydx[], G4double h, G4double yout[], G4double yerr[])
G4double	DistChord () const
G4int	IntegratorOrder () const
G4bool	isFSAL () const
G4double *	getLastDydx ()
	G4BogackiShampine23 (const G4BogackiShampine23 &)
G4BogackiShampine23 &	operator= (const G4BogackiShampine23 &)
Public Member Functions inherited from G4MagIntegratorStepper
	G4MagIntegratorStepper (G4EquationOfMotion *Equation, G4int numIntegrationVariables, G4int numStateVariables=12, bool isFSAL=false)
virtual	~G4MagIntegratorStepper ()
virtual void	ComputeRightHandSide (const G4double y[], G4double dydx[])
void	NormaliseTangentVector (G4double vec[6])
void	NormalisePolarizationVector (G4double vec[12])
void	RightHandSide (const double y[], double dydx[])
G4int	GetNumberOfVariables () const
G4int	GetNumberOfStateVariables () const
G4int	IntegrationOrder ()
G4EquationOfMotion *	GetEquationOfMotion ()
void	SetEquationOfMotion (G4EquationOfMotion *newEquation)
unsigned long	GetfNoRHSCalls ()
void	ResetfNORHSCalls ()
bool	IsFSAL ()

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

Detailed Description

Definition at line 50 of file G4BogackiShampine23.hh.

Constructor & Destructor Documentation

G4BogackiShampine23::G4BogackiShampine23	(	G4EquationOfMotion *	EqRhs,
		G4int	numberOfVariables = 6,
		G4bool	primary = true
	)

Definition at line 61 of file G4BogackiShampine23.cc.

  : G4MagIntegratorStepper(EqRhs, noIntegrationVariables),
    fLastStepLength(0.), fAuxStepper(0)
{
  const G4int numberOfVariables = noIntegrationVariables;

  ak2 = new G4double[numberOfVariables] ;
  ak3 = new G4double[numberOfVariables] ;
  ak4 = new G4double[numberOfVariables] ;

  pseudoDydx_for_DistChord = new G4double[numberOfVariables];

  const G4int numStateVars = std::max(noIntegrationVariables,
                                      GetNumberOfStateVariables() );  

  yTemp = new G4double[numberOfVariables] ;
  yIn = new G4double[numberOfVariables] ;
  
  fLastInitialVector = new G4double[numStateVars] ;
  fLastFinalVector = new G4double[numStateVars] ;
  fLastDyDx = new G4double[numStateVars];

  fMidVector = new G4double[numStateVars];
  fMidError =  new G4double[numStateVars];
  if( primary )
  {
    fAuxStepper = new G4BogackiShampine23(EqRhs, numberOfVariables, !primary);
  }
}

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G4BogackiShampine23::~G4BogackiShampine23

(

)

Definition at line 95 of file G4BogackiShampine23.cc.

{
  delete[] ak2;
  delete[] ak3;
  delete[] ak4;

  delete[] yTemp;
  delete[] yIn;

  delete[] fLastInitialVector;
  delete[] fLastFinalVector;
  delete[] fLastDyDx;
  delete[] fMidVector;
  delete[] fMidError;

  delete fAuxStepper;
}

G4BogackiShampine23::G4BogackiShampine23

(

const G4BogackiShampine23 &

)

Member Function Documentation

G4double G4BogackiShampine23::DistChord ( ) const

virtual

Implements G4MagIntegratorStepper.

Definition at line 200 of file G4BogackiShampine23.cc.

{
  G4double distLine, distChord;
  G4ThreeVector initialPoint, finalPoint, midPoint;

  // Store last initial and final points (they will be overwritten in self-Stepper call!)
  initialPoint = G4ThreeVector( fLastInitialVector[0],
                                fLastInitialVector[1], fLastInitialVector[2]);
  finalPoint   = G4ThreeVector( fLastFinalVector[0],
                                fLastFinalVector[1],  fLastFinalVector[2]);

  // Do half a step using StepNoErr

  fAuxStepper->Stepper( fLastInitialVector, fLastDyDx, 0.5 * fLastStepLength,
           fMidVector,   fMidError );

  midPoint = G4ThreeVector( fMidVector[0], fMidVector[1], fMidVector[2]);

  // Use stored values of Initial and Endpoint + new Midpoint to evaluate
  //  distance of Chord


  if (initialPoint != finalPoint)
  {
     distLine  = G4LineSection::Distline( midPoint, initialPoint, finalPoint );
     distChord = distLine;
  }
  else
  {
     distChord = (midPoint-initialPoint).mag();
  }
  return distChord;
}

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G4double* G4BogackiShampine23::getLastDydx

(

)

G4int G4BogackiShampine23::IntegratorOrder ( ) const

inlinevirtual

Implements G4MagIntegratorStepper.

Definition at line 70 of file G4BogackiShampine23.hh.

{ return 2; }

G4bool G4BogackiShampine23::isFSAL ( ) const

inline

Definition at line 71 of file G4BogackiShampine23.hh.

{ return true; }

G4BogackiShampine23& G4BogackiShampine23::operator=

(

const G4BogackiShampine23 &

)

void G4BogackiShampine23::Stepper ( const G4double  y[], const G4double  dydx[], G4double  h, G4double  yout[], G4double  yerr[]  )

virtual

Implements G4MagIntegratorStepper.

Definition at line 128 of file G4BogackiShampine23.cc.

{
    
 G4int i;

 const G4double  b21 = 0.5 ,
                 b31 = 0. , b32 = 3.0/4.0 ,
                 b41 = 2.0/9.0, b42 = 1.0/3.0 , b43 = 4.0/9.0;


 const G4double  dc1 = b41 - 7.0/24.0 ,  dc2 = b42 - 1.0/4.0 ,
                 dc3 = b43 - 1.0/3.0 , dc4 = - 0.125 ;
    
    

 // Initialise time to t0, needed when it is not updated by the integration.
 //        [ Note: Only for time dependent fields (usually electric)
 //                  is it neccessary to integrate the time.]
 yOut[7] = yTemp[7]   = yIn[7];

 const G4int numberOfVariables= this->GetNumberOfVariables();   // The number of variables to be integrated over

   //  Saving yInput because yInput and yOut can be aliases for same array

   for(i=0;i<numberOfVariables;i++)
   {
        yIn[i]=yInput[i];
   }
 // RightHandSide(yIn, dydx) ;              // 1st Step --Not doing, getting passed
    
    for(i=0;i<numberOfVariables;i++)
    {
        yTemp[i] = yIn[i] + b21*Step*DyDx[i] ;
    }
    RightHandSide(yTemp, ak2) ;              // 2nd Step
    
    for(i=0;i<numberOfVariables;i++)
    {
        yTemp[i] = yIn[i] + Step*(b31*DyDx[i] + b32*ak2[i]) ;
    }
    RightHandSide(yTemp, ak3) ;              // 3rd Step
    
    for(i=0;i<numberOfVariables;i++)
    {
        yOut[i] = yIn[i] + Step*(b41*DyDx[i] + b42*ak2[i] + b43*ak3[i]) ;
    }
    RightHandSide(yOut, ak4) ;              // 4th Step
    
    for(i=0;i<numberOfVariables;i++)
    {
        //         yOut[i] = yIn[i] + Step*(c1*DyDx[i]+ c2*ak2[i] + c3*ak3[i] + c4*ak4[i]);
        
        yErr[i] = Step*(dc1*DyDx[i] + dc2*ak2[i] + dc3*ak3[i] +
                        dc4*ak4[i] ) ;

        
        // Store Input and Final values, for possible use in calculating chord
        fLastInitialVector[i] = yIn[i] ;
        fLastFinalVector[i]   = yOut[i];
        fLastDyDx[i]          = DyDx[i];
    }
    // NormaliseTangentVector( yOut ); // Not wanted
    
    fLastStepLength =Step;
    
    return ;
}

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

• geant4.10.03.p01/source/geometry/magneticfield/include/G4BogackiShampine23.hh
• geant4.10.03.p01/source/geometry/magneticfield/src/G4BogackiShampine23.cc