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//
// G4ChordFinder inline implementations
//
// Author: John Apostolakis (CERN), 25.02.1997 - Design and implementation
// --------------------------------------------------------------------

inline 
void G4ChordFinder::SetIntegrationDriver(G4VIntegrationDriver* driver)
{
  fIntgrDriver = driver;
}

inline
G4VIntegrationDriver* G4ChordFinder::GetIntegrationDriver()
{
  return fIntgrDriver;
}

inline
G4double G4ChordFinder::GetDeltaChord() const
{
  return fDeltaChord;
}

inline
void G4ChordFinder::SetDeltaChord(G4double newval)
{
  fDeltaChord = newval;
}

inline
void G4ChordFinder::ResetStepEstimate()
{ 
  fIntgrDriver->OnStartTracking();
}

inline
G4int G4ChordFinder::SetVerbose( G4int newvalue )
{ 
  G4int oldval = fStatsVerbose; 
  fStatsVerbose = newvalue;
  return oldval; 
}

// A  member that calculates the inverse parabolic through
// the three points (x,y) and returns the value x that, for the
// inverse parabolic, corresponds to y=0.
//
inline
G4double G4ChordFinder::InvParabolic ( const G4double xa, const G4double ya,
                                       const G4double xb, const G4double yb,
                                       const G4double xc, const G4double yc )
{
  const G4double R = yb/yc,
                 S = yb/ya,
                 T = ya/yc;
  const G4double Q = (T-1)*(R-1)*(S-1);
  if (std::fabs(Q) <DBL_MIN ) { return  DBL_MAX; }
        
  const G4double P = S*(T*(R-T)*(xc-xb) - (1-R)*(xb-xa));
  return xb + P/Q;
}

inline G4double
G4ChordFinder::AdvanceChordLimited(G4FieldTrack& yCurrent,
                                   G4double stepInitial,
                                   G4double epsStep_Relative,
                             const G4ThreeVector& /*latestSafetyOrigin*/,
                                   G4double /*lasestSafetyRadius*/)
{
  return fIntgrDriver->AdvanceChordLimited(yCurrent, stepInitial,
                                           epsStep_Relative, fDeltaChord);
}

inline
void G4ChordFinder::OnComputeStep(const G4FieldTrack* track)
{ 
  fIntgrDriver->OnComputeStep(track);
}