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//
// INCL++ intra-nuclear cascade model
// Pekka Kaitaniemi, CEA and Helsinki Institute of Physics
// Davide Mancusi, CEA
// Alain Boudard, CEA
// Sylvie Leray, CEA
// Joseph Cugnon, University of Liege
//
#define INCLXX_IN_GEANT4_MODE 1

#include "globals.hh"

/** \file G4INCLInverseInterpolationTable.hh
 * \brief Simple interpolation table for the inverse of a IFunction1D functor
 *
 * \date 16 July 2012
 * \author Davide Mancusi
 */

#ifndef G4INCLINVERSEINTERPOLATIONTABLE_HH_
#define G4INCLINVERSEINTERPOLATIONTABLE_HH_

#include "G4INCLIFunction1D.hh"
#include <algorithm>
#include <functional>
#include <sstream>

namespace G4INCL {

  // Forward declaration
  class InverseInterpolationTable;

  /// \brief Interpolation node
  class InterpolationNode {
    public:
      InterpolationNode(const G4double x0, const G4double y0, const G4double yPrime0) :
        x(x0),
        y(y0),
        yPrime(yPrime0)
    {}

      virtual ~InterpolationNode() {}

      G4bool operator<(const InterpolationNode &rhs) const {
        return (x < rhs.x);
      }

      G4bool operator<=(const InterpolationNode &rhs) const {
        return (x <= rhs.x);
      }

      G4bool operator>(const InterpolationNode &rhs) const {
        return (x > rhs.x);
      }

      G4bool operator>=(const InterpolationNode &rhs) const {
        return (x >= rhs.x);
      }

      /// \brief Overloaded comparison operator for STL algorithms
      friend G4bool operator<(const InterpolationNode &lhs, const G4double rhs) {
        return lhs.x < rhs;
      }

      G4double getX() const { return x; }
      G4double getY() const { return y; }
      G4double getYPrime() const { return yPrime; }

      void setX(const G4double x0) { x=x0; }
      void setY(const G4double y0) { y=y0; }
      void setYPrime(const G4double yPrime0) { yPrime=yPrime0; }

      std::string print() const {
        std::stringstream message;
        message << "x, y, yPrime: " << x << '\t' << y << '\t' << yPrime << std::endl;
        return message.str();
      }

    protected:
      /// \brief abscissa
      G4double x;
      /// \brief function value
      G4double y;
      /// \brief function derivative
      G4double yPrime;
  };

  /// \brief Class for interpolating the inverse of a 1-dimensional function
  class InverseInterpolationTable : public IFunction1D {
    public:
      InverseInterpolationTable(IFunction1D const &f, const unsigned int nNodes=30);
      InverseInterpolationTable(std::vector<G4double> const &x, std::vector<G4double> const &y);
      virtual ~InverseInterpolationTable() {}

      unsigned int getNumberOfNodes() const { return nodes.size(); }

      std::vector<G4double> getNodeAbscissae() const {
        std::vector<G4double> x(nodes.size());
        std::transform(nodes.begin(), nodes.end(), x.begin(),
            std::mem_fun_ref(&InterpolationNode::getX));
        return x;
      }

      std::vector<G4double> getNodeValues() const {
        std::vector<G4double> y(nodes.size());
        std::transform(nodes.begin(), nodes.end(), y.begin(),
            std::mem_fun_ref(&InterpolationNode::getY));
        return y;
      }

      G4double operator()(const G4double x) const;

      std::string print() const;

    private:
      /// \brief Initialise the values of the node derivatives
      void initDerivatives();

      /// \brief Set the function domain
      void setFunctionDomain();

      /// \brief Interpolating nodes
      std::vector<InterpolationNode> nodes;

  };

}

#endif // G4INCLINVERSEINTERPOLATIONTABLE_HH_