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//
// $Id$
// GEANT4 tag $Name: geant4-09-01-ref-00 $
//
// Author: Maria Grazia Pia (Maria.Grazia.Pia@cern.ch)
//
// History:
// -----------
// 31 Jul 2001   MGP        Created
//
// -------------------------------------------------------------------

#include "G4RDLogLogInterpolation.hh"

// Constructor

G4RDLogLogInterpolation::G4RDLogLogInterpolation()
{ }

// Destructor

G4RDLogLogInterpolation::~G4RDLogLogInterpolation()
{ }

G4RDVDataSetAlgorithm* G4RDLogLogInterpolation::Clone() const 
{ return new G4RDLogLogInterpolation; }


G4double G4RDLogLogInterpolation::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 = (std::log10(d1)*std::log10(e2/x) + std::log10(d2)*std::log10(x/e1)) / std::log10(e2/e1);
      value = std::pow(10.,value);
    }
  else
    {
      value = data[nBins];
    }

  return value;
}
