G4SimpleHeum.cc

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//
// G4SimpleHeum implementation
//
// Created: W.Wander <wwc@mit.edu>, 12/09/1997 
// -------------------------------------------------------------------
 
#include "G4SimpleHeum.hh"
#include "G4ThreeVector.hh"
 
//
// Constructor
//
G4SimpleHeum::G4SimpleHeum(G4EquationOfMotion* EqRhs, G4int num_variables)
  : G4MagErrorStepper(EqRhs, num_variables),
    fNumberOfVariables(num_variables)
{
  dydxTemp  = new G4double[fNumberOfVariables] ; 
  dydxTemp2 = new G4double[fNumberOfVariables] ;
  yTemp     = new G4double[fNumberOfVariables] ; 
  yTemp2    = new G4double[fNumberOfVariables] ;
}
 
//
// Destructor
//
G4SimpleHeum::~G4SimpleHeum()
{
  delete [] dydxTemp;
  delete [] dydxTemp2;
  delete [] yTemp;
  delete [] yTemp2;
}
 
//
// DumbStepper
//
void
G4SimpleHeum::DumbStepper( const G4double yIn[],
                           const G4double dydx[],
                                 G4double h,
                                 G4double yOut[] )
{
  for( G4int i = 0; i < fNumberOfVariables; ++i ) 
  {
    yTemp[i] = yIn[i] + (1.0/3.0) * h *  dydx[i] ;
  }
  
  RightHandSide(yTemp,dydxTemp);
 
  for( G4int i = 0; i < fNumberOfVariables; ++i ) 
  {
    yTemp2[i] = yIn[i] + (2.0/3.0) * h * dydxTemp[i] ;
  }
 
  RightHandSide(yTemp2,dydxTemp2);
 
  for( G4int i = 0; i < fNumberOfVariables; ++i ) 
  {
    yOut[i] = yIn[i] + h * (0.25 * dydx[i] + 0.75 * dydxTemp2[i]);
  }
      
  if ( fNumberOfVariables == 12 ) { NormalisePolarizationVector( yOut ); }
}