// -*- C++ -*-
#ifndef RIVET_ParisiTensor_HH
#define RIVET_ParisiTensor_HH

#include "Rivet/Projection.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/Sphericity.hh"
#include "Rivet/Event.hh"

namespace Rivet {


  class ParisiTensor : public Projection {
  public:

    ParisiTensor(const FinalState& fsp)
    {
      setName("ParisiTensor");
      declare(fsp, "FS");
      declare(Sphericity(fsp, 1.0), "Sphericity");
      clear();
    }

    DEFAULT_RIVET_PROJ_CLONE(ParisiTensor);


  protected:

    void project(const Event& e);

    CmpState compare(const Projection& p) const;


  public:

    void clear();


  public:

    double C() const { return _C; }
    double D() const { return _D; }

    double lambda1() const { return _lambda[0]; }
    double lambda2() const { return _lambda[1]; }
    double lambda3() const { return _lambda[2]; }


  private:

    double _C, _D;

    double _lambda[3];

  };


}


#endif