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//
// $Id: G4CachedMagneticField.cc,v 1.1 2009/11/05 11:06:13 japost Exp $
// GEANT4 tag $Name: geant4-09-04-beta-01 $
//
// --------------------------------------------------------------------

#include "G4CachedMagneticField.hh"

G4CachedMagneticField::G4CachedMagneticField(G4MagneticField *pMagField, 
					     G4double         distance)
  : G4MagneticField(), 
    fLastLocation(DBL_MAX,DBL_MAX,DBL_MAX),
    fLastValue(DBL_MAX,DBL_MAX,DBL_MAX),
    fCountCalls(0),  fCountEvaluations(0)
{
  fpMagneticField=     pMagField;
  fDistanceConst= distance;

  // G4cout << " Cached-B-Field constructor> Distance = " << distance << G4endl;
  this->ClearCounts(); 
}

G4CachedMagneticField::~G4CachedMagneticField()
{
}

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

G4CachedMagneticField::G4CachedMagneticField(const G4CachedMagneticField &rightCMF)
  : G4MagneticField()
{
  fpMagneticField=      rightCMF.fpMagneticField;
  fDistanceConst = rightCMF.fDistanceConst;
  fLastLocation  = rightCMF.fLastLocation;
  fLastValue     = rightCMF.fLastValue;
  this->ClearCounts(); 
}

G4CachedMagneticField& G4CachedMagneticField::operator = (const G4CachedMagneticField &p)
{
  if (&p == this) return *this; *this = p; return *this;
}

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

  // G4cout << "Cache-B-field called at " << newLocation << G4endl;

  G4double      distSq= (newLocation-fLastLocation).mag2();
  fCountCalls++;
  if( distSq < fDistanceConst*fDistanceConst ) { 
     Bfield[0] = fLastValue.x();
     Bfield[1] = fLastValue.y();
     Bfield[2] = fLastValue.z();
  }else{
     // G4CachedMagneticField* thisNonC= const_cast<G4CachedMagneticField*>(this);
     fpMagneticField->GetFieldValue( Point, Bfield );
     // G4cout << " Evaluating. " << G4endl;
     fCountEvaluations++;
     // thisNonC->
     fLastLocation= G4ThreeVector( Point[0],  Point[1],  Point[2] );
     // thisNonC->
     fLastValue=    G4ThreeVector( Bfield[0], Bfield[1], Bfield[2] );
  }
}