// ----------------------------------------------------------------------------
// $Id: LCDJetFinder.h,v 1.2 2001/06/19 16:59:15 toshi Exp $
// ----------------------------------------------------------------------------
//
// $Log: LCDJetFinder.h,v $
// Revision 1.2  2001/06/19 16:59:15  toshi
// Just add $ID: $ in the top of this file.
//
//
#ifndef LCDJETFINDER_H
#define LCDJETFINDER_H

// Virtual JetFinder base class
//
// V0.0 Mar 01/99 : R. Shanks  Derived from Java routines written by G.Bower. 
// V1.0 May 15/00 : M.Iwasaki  Make necessary modifications, and change classes
//                             Merge JadeEJetFinder, JadeJetFinder, 
//                             DurhamJetfinder, and JetFinder
//                             into one JetFinder.
// V1.1 Aug 15 00 : M.Iwasaki  Change calcinvmass. Remove DurhamJetFinder, 
//                             JadeJetFinder, and JadeEJetFinder classes.
//                             Add SetDURHAM, SetJADE, or SetJADEE. 
// V1.2 Apr 17 01 : T.Abe      Use TClonesArray

#include "TLorentzVector.h"
#include "TVector3.h"
#include "TObjArray.h"
#include "TClonesArray.h"
#include "TArrayI.h"
#include "TClass.h"

//_____________________________________________________________________
//  ----------------------
//   JetFinder Base Class
//  ----------------------
//
class LCDJetFinder : public TObject {
  //class LCDJetFinder {
public:
  LCDJetFinder();
  LCDJetFinder(Double_t ycut);
  ~LCDJetFinder();
  
  void SetPartList(TObjArray* e);    
  // Input the particle 4(3)-vector list
  // e: 4-vector  TLorentzVector ..(px,py,pz,E) or
  //    3-vector  TVector3       ..(px,py,pz) 
  // If you input TVector3, the energy of particle
  // will be E = sqrt(px**2 + py**2 + pz**2) 

  void SetYCut(Double_t ycut);
  // Set the YCut value

  void doFindJets();
  void doFindJets(Double_t ycut);
  // Clustering the particles into Jets  
    
  Int_t doFindJets(Int_t njet);
  // Clustering the particles into Jets to force to make given # of jets.
    
  Int_t njets(){ return m_njets; };
  // The number of jets found.  

  TLorentzVector* jet4vec(Int_t index);
  // Return the 4 vector of a jet (particle sum).
  // index: The index of the jet of interest  

  Int_t nParticlesPerJet(Int_t index);
  // Number of particles in a particular jet
  // index: The index of the jet of interest  

  TArrayI GetPartIndex(){ return m_ipart_jet_assoc; };
  Int_t   GetPartIndexAt(Int_t a){ return m_ipart_jet_assoc[a]; };
  TArrayI* GetPartIndexPtr(){ return &m_ipart_jet_assoc; };
  // Return the particle index array.
  // m_ipart_jet_assoc[i] = j means 
  // particle i is placed in jet j.  

  Double_t GetYmin() { return m_ymin; }

  Int_t fewestParts(){ return m_ifewest_parts; };
  // minimum number of particles to make a jet.  

  Double_t GetYCut() { return m_dycut; };
  // Obtain the current ycut
  
  void SetDURHAM(); // Select DURHAM algorithm
  void SetJADE();   //        JADE   algorithm
  void SetJADEE();  //        JADE E algorithm

  Double_t calcinvmass(const TLorentzVector &jet1, 
		       const TLorentzVector &jet2);

private:
  Int_t m_njets;
  // Number of jets found  

  Double_t m_ymin;
  // minimum value of ycut.

  TClonesArray* m_jet;
  // m_jet[i] is the 4 vector sum of all the particles in jet i.  

  TArrayI m_ipart_jet_assoc; 
  // m_ipart_jet_assoc[i] = j means particle i was placed in jet j.  

  TArrayI m_inparts_per_jet; 
  // m_inparts_per_jet[i] = j means jet i has j particles in it.  

  Int_t m_ifewest_parts;
  // m_ifewest_parts is number of particles in the jet 
  // with the fewest particles.  

  Double_t m_evis;
  Double_t m_dycut;  
  Int_t m_algorithm; // Algorithm used in Jet clustering

  const static Int_t UNASSOC;
  const static Int_t DURHAM;
  const static Int_t JADE;  
  const static Int_t JADEE;

  //protected:  
  TObjArray*    m_4vec;
  TClonesArray* m_part;

public:
  ClassDef(LCDJetFinder,3) // Jetfinder base class	    
};       


#endif