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//
// $Id: G4LinInterpolator.cc,v 1.2 2010/11/19 17:16:21 pia Exp $
// GEANT4 tag $Name: geant4-09-04-ref-00 $
//
// Author: Maria Grazia Pia (Maria.Grazia.Pia@cern.ch)
//
// History:
// -----------
// 31 Jul 2001   MGP        Created
// 31 Jul 2008   MGP        Revised and renamed to G4LinInterpolator
//
// -------------------------------------------------------------------

#include "G4LinInterpolator.hh"

// Constructor

G4LinInterpolator::G4LinInterpolator()
{ }

// Destructor

G4LinInterpolator::~G4LinInterpolator()
{ }


G4IInterpolator* G4LinInterpolator::Clone() const 
{ return new G4LinInterpolator; }

G4double G4LinInterpolator::Calculate(G4double x, G4int bin, 
				      const G4DataVector& points, 
				      const G4DataVector& data) const
{
  G4int nBins = data.size() - 1;
  G4double value = 0.;
  if (x < points[0])
    {
      value = 0.;
    }
  else if (bin < nBins)
    {
      G4double e1 = points[bin];
      G4double e2 = points[bin+1];
      G4double d1 = data[bin];
      G4double d2 = data[bin+1];
      value = d1 + (d2 - d1)*(x - e1)/(e2 - e1);
    }
  else
    {
      value = data[nBins];
    }
  return value;
}