G4CashKarpRKF45 Class Reference

#include <G4CashKarpRKF45.hh>

Inheritance diagram for G4CashKarpRKF45:

Public Member Functions
	G4CashKarpRKF45 (G4EquationOfMotion *EqRhs, G4int numberOfVariables=6, G4bool primary=true)
	~G4CashKarpRKF45 () override
	G4CashKarpRKF45 (const G4CashKarpRKF45 &)=delete
G4CashKarpRKF45 &	operator= (const G4CashKarpRKF45 &)=delete
void	Stepper (const G4double y[], const G4double dydx[], G4double h, G4double yout[], G4double yerr[]) override
G4double	DistChord () const override
G4int	IntegratorOrder () const override
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
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
G4int	IntegrationOrder ()
G4EquationOfMotion *	GetEquationOfMotion ()
const G4EquationOfMotion *	GetEquationOfMotion () const
void	SetEquationOfMotion (G4EquationOfMotion *newEquation)
unsigned long	GetfNoRHSCalls ()
void	ResetfNORHSCalls ()
G4bool	IsFSAL () const
G4bool	isQSS () const
void	SetIsQSS (G4bool val)

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

Detailed Description

Definition at line 44 of file G4CashKarpRKF45.hh.

Constructor & Destructor Documentation

G4CashKarpRKF45() [1/2]

G4CashKarpRKF45::G4CashKarpRKF45	(	G4EquationOfMotion *	EqRhs,
		G4int	numberOfVariables = 6,
		G4bool	primary = true )

Definition at line 47 of file G4CashKarpRKF45.cc.

  : G4MagIntegratorStepper(EqRhs, noIntegrationVariables)
{
  const G4int numberOfVariables =
      std::max( noIntegrationVariables,
               ( ( (noIntegrationVariables-1)/4 + 1 ) * 4 ) );
  // For better alignment with cache-line
  
  ak2 = new G4double[numberOfVariables] ;
  ak3 = new G4double[numberOfVariables] ;
  ak4 = new G4double[numberOfVariables] ;
  ak5 = new G4double[numberOfVariables] ;
  ak6 = new G4double[numberOfVariables] ;
  // ak7 = 0;
 
  // Must ensure space extra 'state' variables exists - i.e. yIn[7]
  const G4int numStateMax  = std::max(GetNumberOfStateVariables(), 8);  
  const G4int numStateVars = std::max(noIntegrationVariables,
                                      numStateMax );
                                   // GetNumberOfStateVariables() ); 
                                      
  yTemp = new G4double[numStateVars] ;
  yIn = new G4double[numStateVars] ;
 
  fLastInitialVector = new G4double[numStateVars] ;
  fLastFinalVector = new G4double[numStateVars] ;
  fLastDyDx = new G4double[numberOfVariables];
 
  fMidVector = new G4double[numStateVars];
  fMidError =  new G4double[numStateVars];
  if( primary )
  { 
    fAuxStepper = new G4CashKarpRKF45(EqRhs, numberOfVariables, !primary);
  }
}

Referenced by G4CashKarpRKF45().

~G4CashKarpRKF45()

G4CashKarpRKF45::~G4CashKarpRKF45 ( )

override

Definition at line 89 of file G4CashKarpRKF45.cc.

{
  delete [] ak2;
  delete [] ak3;
  delete [] ak4;
  delete [] ak5;
  delete [] ak6;
  // delete [] ak7;
  delete [] yTemp;
  delete [] yIn;
 
  delete [] fLastInitialVector;
  delete [] fLastFinalVector;
  delete [] fLastDyDx;
  delete [] fMidVector;
  delete [] fMidError; 
 
  delete fAuxStepper;
}

G4CashKarpRKF45() [2/2]

G4CashKarpRKF45::G4CashKarpRKF45 ( const G4CashKarpRKF45 & )

delete

Member Function Documentation

DistChord()

G4double G4CashKarpRKF45::DistChord ( ) const

overridevirtual

Implements G4MagIntegratorStepper.

Definition at line 238 of file G4CashKarpRKF45.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;
}

IntegratorOrder()

G4int G4CashKarpRKF45::IntegratorOrder ( ) const

inlineoverridevirtual

Implements G4MagIntegratorStepper.

Definition at line 64 of file G4CashKarpRKF45.hh.

{ return 4; }

operator=()

G4CashKarpRKF45 & G4CashKarpRKF45::operator= ( const G4CashKarpRKF45 & )

delete

Stepper()

void G4CashKarpRKF45::Stepper ( const G4double y[], const G4double dydx[], G4double h, G4double yout[], G4double yerr[] )

overridevirtual

Implements G4MagIntegratorStepper.

Definition at line 120 of file G4CashKarpRKF45.cc.

{
  // const G4int nvar = 6 ;
  // const G4double a2 = 0.2 , a3 = 0.3 , a4 = 0.6 , a5 = 1.0 , a6 = 0.875;
  G4int i;
 
  const G4double  b21 = 0.2 ,
                  b31 = 3.0/40.0 , b32 = 9.0/40.0 ,
                  b41 = 0.3 , b42 = -0.9 , b43 = 1.2 ,
 
                  b51 = -11.0/54.0 , b52 = 2.5 , b53 = -70.0/27.0 ,
                  b54 = 35.0/27.0 ,
 
                  b61 = 1631.0/55296.0 , b62 =   175.0/512.0 ,
                  b63 =  575.0/13824.0 , b64 = 44275.0/110592.0 ,
                  b65 =  253.0/4096.0 ,
 
                  c1 = 37.0/378.0 , c3 = 250.0/621.0 , c4 = 125.0/594.0 ,
                  c6 = 512.0/1771.0 , dc5 = -277.0/14336.0 ;
 
  const G4double dc1 = c1 - 2825.0/27648.0 ,  dc3 = c3 - 18575.0/48384.0 ,
                 dc4 = c4 - 13525.0/55296.0 , dc6 = c6 - 0.25 ;
 
  // 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] = yInput[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
 
  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)
  {
    yTemp[i] = yIn[i] + Step*(b41*dydx[i] + b42*ak2[i] + b43*ak3[i]) ;
  }
  RightHandSide(yTemp, ak4) ;              // 4th Step
 
  for(i=0; i<numberOfVariables; ++i)
  {
    yTemp[i] = yIn[i] + Step*(b51*dydx[i]
                      + b52*ak2[i] + b53*ak3[i] + b54*ak4[i]) ;
  }
  RightHandSide(yTemp, ak5) ;              // 5th Step
 
  for(i=0; i<numberOfVariables; ++i)
  {
    yTemp[i] = yIn[i] + Step*(b61*dydx[i]
                      + b62*ak2[i] + b63*ak3[i] + b64*ak4[i] + b65*ak5[i]) ;
  }
  RightHandSide(yTemp, ak6) ;              // 6th Step
 
  for(i=0; i<numberOfVariables; ++i)
  {
    // Accumulate increments with proper weights
    //
    yOut[i] = yIn[i] + Step*(c1*dydx[i] + c3*ak3[i] + c4*ak4[i] + c6*ak6[i]) ;
 
    // Estimate error as difference between 4th and 5th order methods
    //
    yErr[i] = Step*(dc1*dydx[i]
            + dc3*ak3[i] + dc4*ak4[i] + dc5*ak5[i] + dc6*ak6[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;
} 

Referenced by DistChord().

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

• G4CashKarpRKF45.hh
• G4CashKarpRKF45.cc