G4CachedMagneticField.cc

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//
// G4CachedMagneticField implementation
//
// Author: J.Apostolakis, 20 July 2009.
// --------------------------------------------------------------------

#include "G4CachedMagneticField.hh"

G4CachedMagneticField::G4CachedMagneticField(G4MagneticField* pMagField, 
                                             G4double         distance)
  : G4MagneticField(), fpMagneticField(pMagField), fDistanceConst(distance),
    fLastLocation(DBL_MAX,DBL_MAX,DBL_MAX), fLastValue(DBL_MAX,DBL_MAX,DBL_MAX)
{
  ClearCounts(); 
}

G4Field* G4CachedMagneticField::Clone() const
{
  // Cannot use copy constructor: need to clone the associated magnetic field

  G4MagneticField* aF = static_cast<G4MagneticField*>(fpMagneticField->Clone());
  G4CachedMagneticField* cloned = new G4CachedMagneticField(aF, fDistanceConst);

  cloned->fLastLocation = fLastLocation;
  cloned->fLastValue = fLastValue;
  return cloned;
}

G4CachedMagneticField::~G4CachedMagneticField()
{
}

void
G4CachedMagneticField::ReportStatistics()
{
  G4cout << " Cached field: " << G4endl
         << "   Number of calls:        " << fCountCalls << G4endl
         << "   Number of evaluations : " << fCountEvaluations << G4endl;                     
}

G4CachedMagneticField::
G4CachedMagneticField(const G4CachedMagneticField& rightCMF)
  : G4MagneticField(rightCMF)
{
  fpMagneticField= rightCMF.fpMagneticField;  // NOTE: sharing pointer here!
  fDistanceConst = rightCMF.fDistanceConst;
  fLastLocation  = rightCMF.fLastLocation;
  fLastValue     = rightCMF.fLastValue;
  ClearCounts(); 
}

G4CachedMagneticField&
G4CachedMagneticField::operator = (const G4CachedMagneticField& p)
{
  if (&p == this) { return *this; }
  G4MagneticField::operator=(p);
  fpMagneticField= p.fpMagneticField;  // NOTE: sharing pointer here!
  fDistanceConst = p.fDistanceConst;
  fLastLocation  = p.fLastLocation;
  fLastValue     = p.fLastValue;
  ClearCounts(); 
  return *this;
}

void
G4CachedMagneticField::GetFieldValue( const G4double Point[4],
                                            G4double* Bfield ) const
{
  G4ThreeVector newLocation( Point[0], Point[1], Point[2] );

  G4double      distSq= (newLocation-fLastLocation).mag2();
  ++fCountCalls;
  if( distSq < fDistanceConst*fDistanceConst )
  { 
     Bfield[0] = fLastValue.x();
     Bfield[1] = fLastValue.y();
     Bfield[2] = fLastValue.z();
  }
  else
  {
     fpMagneticField->GetFieldValue( Point, Bfield );
     ++fCountEvaluations;
     fLastLocation = G4ThreeVector( Point[0],  Point[1],  Point[2] );
     fLastValue    = G4ThreeVector( Bfield[0], Bfield[1], Bfield[2] );
  }
}