#ifndef ALIGENPYTHIA_H
#define ALIGENPYTHIA_H
/* Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
 * See cxx source for full Copyright notice                               */


/* $Id$ */

//
// Generator using the TPythia interface (via AliPythia)
// to generate pp collisions.
// Using SetNuclei() also nuclear modifications to the structure functions
// can be taken into account. This makes, of course, only sense for the
// generation of the products of hard processes (heavy flavor, jets ...)
//
// andreas.morsch@cern.ch
//

#include "AliGenMC.h"
#include "AliPythia.h"

class AliPythia;
class TParticle;
class AliGenPythiaEventHeader;
class AliGenEventHeader;
class AliStack;
class AliRunLoader;
class TObjArray; 

class AliGenPythia : public AliGenMC
{
 public:

    typedef enum {kFlavorSelection, kParentSelection, kHeavyFlavor} StackFillOpt_t;
    typedef enum {kCountAll, kCountParents, kCountTrackables} CountMode_t;
    typedef enum {kCluster, kCell} JetRecMode_t;
	  
    AliGenPythia();
    AliGenPythia(Int_t npart);
    virtual ~AliGenPythia();
    virtual void    Generate();
    virtual void    Init();
    // Range of events to be printed
    virtual void    SetEventListRange(Int_t eventFirst=-1, Int_t eventLast=-1);
    // Select process type
    virtual void    SetProcess(Process_t proc = kPyCharm) {fProcess = proc;}
    virtual void    SetTune(Int_t itune) {fItune = itune;}
    virtual void    SetSeed(UInt_t seed);

    // Select structure function
    virtual void    SetStrucFunc(StrucFunc_t func =  kCTEQ5L) {fStrucFunc = func;}
    // Rewieght pt, hard spectrum with pT/p0^n, set power n
    virtual void    SetWeightPower(Float_t power = 0.) { fWeightPower = power; }
    // Select pt of hard scattering 
    virtual void    SetPtHard(Float_t ptmin = 0, Float_t ptmax = 1.e10)
	{fPtHardMin = ptmin; fPtHardMax = ptmax; }
    // y of hard scattering
    virtual void    SetYHard(Float_t ymin = -1.e10, Float_t ymax = 1.e10)
	{fYHardMin = ymin; fYHardMax = ymax; }
    // Set initial and final state gluon radiation
    virtual void    SetGluonRadiation(Int_t iIn, Int_t iFin)
	{fGinit = iIn; fGfinal = iFin;}
    virtual void SetColorReconnectionOff(Int_t iflag=0){fCRoff=iflag;} 
   // Intrinsic kT
    virtual void    SetPtKick(Float_t kt = 1.)
	{fPtKick = kt;}
    // Use the Pythia 6.3 new multiple interations scenario
    virtual void    UseNewMultipleInteractionsScenario() {fNewMIS = kTRUE;}
    // Switch off heavy flavors
    virtual void    SwitchHFOff() {fHFoff = kTRUE;}
    // Set centre of mass energy
    virtual void    SetEnergyCMS(Float_t energy = 5500) {fEnergyCMS = energy;}
    // Treat protons as inside nuclei with mass numbers a1 and a2
    virtual void    SetNuclei(Int_t a1, Int_t a2, Int_t pdfset = 0);
    // Set colliding nuclei ("p","n",...)
    virtual void    SetCollisionSystem(TString projectile, TString target) { fProjectile = projectile; fTarget = target; }
    virtual void    SetNuclearPDF(Int_t pdf) {fNucPdf = pdf;}
    virtual void    SetUseNuclearPDF(Bool_t val) {fUseNuclearPDF = val;}
    virtual void    SetUseLorentzBoost(Bool_t val) {fUseLorentzBoost = val;}
    //
    // Trigger options
    //
    // Energy range for jet trigger
    virtual void    SetJetEtRange(Float_t etmin = 0., Float_t etmax = 1.e4)
	{fEtMinJet = etmin; fEtMaxJet = etmax;}
    // Eta range for jet trigger
    virtual void    SetJetEtaRange(Float_t etamin = -20., Float_t etamax = 20.)
	{fEtaMinJet = etamin; fEtaMaxJet = etamax;}
    // Phi range for jet trigger
    virtual void    SetJetPhiRange(Float_t phimin = 0., Float_t phimax = 360.)
	{fPhiMinJet = TMath::Pi()*phimin/180.; fPhiMaxJet = TMath::Pi()*phimax/180.;}
    // Jet reconstruction mode; default is cone algorithm
    virtual void    SetJetReconstructionMode(Int_t mode = kCell) {fJetReconstruction = mode;}
    // Eta range for gamma trigger 
    virtual void    SetGammaEtaRange(Float_t etamin = -20., Float_t etamax = 20.)
	{fEtaMinGamma = etamin; fEtaMaxGamma = etamax;}
    // Phi range for gamma trigger
    virtual void    SetGammaPhiRange(Float_t phimin = 0., Float_t phimax = 360.)
	{fPhiMinGamma = TMath::Pi()*phimin/180.; fPhiMaxGamma = TMath::Pi()*phimax/180.;}
    // Y range for heavy quark trigger
    virtual void    SetHeavyQuarkYRange(Float_t ymin=-20., Float_t ymax=20.){
      fYMinHQ = ymin;    fYMaxHQ=ymax;   fUseYCutHQ=kTRUE;
    }
  
    // Select events with fragmentation photon, decay photon, pi0 or eta going to PHOS or EMCAL and central barrel
    virtual Bool_t TriggerOnSelectedParticles(Int_t np);
  
    virtual void  SetCheckPHOS         (Bool_t b) {fCheckPHOS    = b;}
    virtual void  SetCheckEMCAL        (Bool_t b) {fCheckEMCAL   = b;}
    virtual void  SetCheckBarrel       (Bool_t b) {fCheckBarrel  = b;}
  
    //virtual void  SetElectronInEMCAL   (Bool_t b) {fEleInEMCAL   = b;}
    //virtual void  SetPhotonInPHOS      (Bool_t b) {fCheckPHOS    = b; fPhotonInCalo     = b;} // Not in use

    virtual void  SetFragPhotonInCalo  (Bool_t b) {                   fFragPhotonInCalo = b;}
    virtual void  SetFragPhotonInBarrel(Bool_t b) {fCheckBarrel  = b; fFragPhotonInCalo = b;}
    virtual void  SetFragPhotonInEMCAL (Bool_t b) {fCheckEMCAL   = b; fFragPhotonInCalo = b;}
    virtual void  SetFragPhotonInPHOS  (Bool_t b) {fCheckPHOS    = b; fFragPhotonInCalo = b;}
  
    virtual void  SetHadronInCalo      (Bool_t b) {                   fHadronInCalo     = b;}
    virtual void  SetHadronInBarrel    (Bool_t b) {fCheckBarrel  = b; fHadronInCalo     = b;}
    virtual void  SetHadronInEMCAL     (Bool_t b) {fCheckEMCAL   = b; fHadronInCalo     = b;}
    virtual void  SetHadronInPHOS      (Bool_t b) {fCheckPHOS    = b; fHadronInCalo     = b;}
  
    virtual void  SetElectronInCalo    (Bool_t b) {                   fEleInCalo        = b;}
    virtual void  SetElectronInBarrel  (Bool_t b) {fCheckBarrel  = b; fEleInCalo        = b;}
    virtual void  SetElectronInEMCAL   (Bool_t b) {fCheckEMCAL   = b; fEleInCalo        = b;}
    virtual void  SetElectronInPHOS    (Bool_t b) {fCheckPHOS    = b; fEleInCalo        = b;}
  
    virtual void  SetDecayPhotonInCalo (Bool_t d)  {fDecayPhotonInCalo = d;}
    virtual void  SetDecayPhotonInBarrel(Bool_t d) {fDecayPhotonInCalo = d; fCheckBarrel  = d;}
    virtual void  SetDecayPhotonInEMCAL(Bool_t d)  {fDecayPhotonInCalo = d; fCheckEMCAL   = d;}
    virtual void  SetDecayPhotonInPHOS (Bool_t d)  {fDecayPhotonInCalo = d; fCheckPHOS    = d;}
  
    virtual void  SetPi0InCalo         (Bool_t b, Bool_t f = kFALSE) {fPi0InCalo = b; fForceNeutralMeson2PhotonDecay = f;}
    virtual void  SetPi0InBarrel       (Bool_t b, Bool_t f = kFALSE) {fPi0InCalo = b; fForceNeutralMeson2PhotonDecay = f; fCheckBarrel= b; }
    virtual void  SetPi0InEMCAL        (Bool_t b, Bool_t f = kFALSE) {fPi0InCalo = b; fForceNeutralMeson2PhotonDecay = f; fCheckEMCAL = b; }
    virtual void  SetPi0InPHOS         (Bool_t b, Bool_t f = kFALSE) {fPi0InCalo = b; fForceNeutralMeson2PhotonDecay = f; fCheckPHOS  = b; }
 
    virtual void  SetEtaInCalo         (Bool_t b, Bool_t f = kFALSE) {fEtaInCalo = b; fForceNeutralMeson2PhotonDecay = f;}
    virtual void  SetEtaInBarrel       (Bool_t b, Bool_t f = kFALSE) {fEtaInCalo = b; fForceNeutralMeson2PhotonDecay = f; fCheckBarrel= b; }
    virtual void  SetEtaInEMCAL        (Bool_t b, Bool_t f = kFALSE) {fEtaInCalo = b; fForceNeutralMeson2PhotonDecay = f; fCheckEMCAL = b; }
    virtual void  SetEtaInPHOS         (Bool_t b, Bool_t f = kFALSE) {fEtaInCalo = b; fForceNeutralMeson2PhotonDecay = f; fCheckPHOS  = b; }

    virtual void  SetPi0PhotonDecayInBarrel(Bool_t b, Bool_t f = kFALSE) {fPi0InCalo = b; fDecayPhotonInCalo = b; fForceNeutralMeson2PhotonDecay = f; fCheckBarrel  = b; }
    virtual void  SetPi0PhotonDecayInEMCAL (Bool_t b, Bool_t f = kFALSE) {fPi0InCalo = b; fDecayPhotonInCalo = b; fForceNeutralMeson2PhotonDecay = f; fCheckEMCAL   = b; }
    virtual void  SetPi0PhotonDecayInPHOS  (Bool_t b, Bool_t f = kFALSE) {fPi0InCalo = b; fDecayPhotonInCalo = b; fForceNeutralMeson2PhotonDecay = f; fCheckPHOS    = b; }

    virtual void  SetEtaPhotonDecayInBarrel(Bool_t b, Bool_t f = kFALSE) {fEtaInCalo = b; fDecayPhotonInCalo = b; fForceNeutralMeson2PhotonDecay = f; fCheckBarrel  = b; }
    virtual void  SetEtaPhotonDecayInEMCAL (Bool_t b, Bool_t f = kFALSE) {fEtaInCalo = b; fDecayPhotonInCalo = b; fForceNeutralMeson2PhotonDecay = f; fCheckEMCAL   = b; }
    virtual void  SetEtaPhotonDecayInPHOS  (Bool_t b, Bool_t f = kFALSE) {fEtaInCalo = b; fDecayPhotonInCalo = b; fForceNeutralMeson2PhotonDecay = f; fCheckPHOS    = b; }

  
    // Trigger on a minimum multiplicity
    virtual void  SetTriggerChargedMultiplicity(Int_t multiplicity, Float_t etamax = 0, Float_t ptmin = -1.) 
    {fTriggerMultiplicity = multiplicity; fTriggerMultiplicityEta = etamax; 
      fTriggerMultiplicityPtMin = ptmin;}
    
    // Trigger on a minimum multiplicity for a given eta range
    virtual void  SetTriggerMultiplicityEtaRange(Int_t multiplicity, Float_t etamin = 0., Float_t etamax = 0., Float_t ptmin = -1.) 
    {fTriggerMultiplicity = multiplicity; fTriggerMultiplicityEtaMin = etamin; fTriggerMultiplicityEtaMax = etamax; 
      fTriggerMultiplicityPtMin = ptmin;}
    
    // Calorimeters acceptance
    // Set Phi in degrees, and Eta coverage, should not be negative
    virtual void  SetBarrelAcceptance(Float_t deta) {fTriggerEta = deta ;}
    virtual void  SetTriggerY(Float_t dy) {fTriggerY = dy;}
    virtual void  SetEMCALAcceptance (Float_t phimin, Float_t phimax, Float_t deta) {fEMCALMinPhi = phimin ; fEMCALMaxPhi = phimax ; fEMCALEta = deta ; }
    virtual void  SetPHOSAcceptance  (Float_t phimin, Float_t phimax, Float_t deta) {fPHOSMinPhi  = phimin ; fPHOSMaxPhi  = phimax ; fPHOSEta  = deta ; }
    virtual void  SetRotateParticleInPHOSeta(Bool_t b) {fCheckPHOSeta = b;}
  
    virtual void  SetTriggerParticleMinPt(Float_t pt) {fTriggerParticleMinPt = pt;}
//    virtual void  SetPhotonMinPt(Float_t pt)          {fPhotonMinPt = pt;}
//    virtual void  SetElectronMinPt(Float_t pt)        {fElectronMinPt = pt;}
    // Trigger and rotate event 
    void RotatePhi(Bool_t& okdd);
  
    // Trigger on a single particle (not related to calorimeter trigger above)
    virtual void    SetTriggerParticle(Int_t particle = 0, Float_t etamax = 0.9, Float_t ptmin = -1, Float_t ptmax = 1000) 
    {fTriggerParticle = particle; fTriggerEta = etamax; fTriggerEtaMin = etamax; fTriggerMinPt = ptmin; fTriggerMaxPt = ptmax;}
    virtual void    SetTriggerParticle(Int_t particle, Float_t etamin, Float_t etamax, Float_t ptmin, Float_t ptmax) 
    {fTriggerParticle = particle; fTriggerEtaMin = etamin, fTriggerEta = etamax; fTriggerMinPt = ptmin; fTriggerMaxPt = ptmax;}

    //
    // Heavy flavor options
    //
    // Set option for feed down from higher family
    virtual void SetFeedDownHigherFamily(Bool_t opt) {
	fFeedDownOpt = opt;
    }
    // Set option for selecting particles kept in stack according to flavor
    // or to parent selection
    virtual void SetStackFillOpt(StackFillOpt_t opt) {
	fStackFillOpt = opt;
    }
    // Set fragmentation option
    virtual void SetFragmentation(Bool_t opt) {
	fFragmentation = opt;
    }
    // Set counting mode
    virtual void SetCountMode(CountMode_t mode) {
	fCountMode = mode;
    }
    //
    // Quenching
    //
    // Set quenching mode 0 = no, 1 = AM, 2 = IL,  3 = NA, 4 = ACS
    virtual void SetQuench(Int_t flag = 0) {fQuench = flag;}
    // Set transport coefficient.
    void SetQhat(Float_t qhat) {fQhat = qhat;}
    //Set initial medium length.
    void SetLength(Float_t length) {fLength = length;}
    //set parameters for pyquen afterburner
    virtual void SetPyquenPar(Float_t t0=1., Float_t tau0=0.1, Int_t nf=0,Int_t iengl=0, Int_t iangl=3)
    {fpyquenT = t0; fpyquenTau = tau0; fpyquenNf=nf;fpyquenEloss=iengl;fpyquenAngle=iangl;}
    virtual void SetHadronisation(Int_t flag = 1) {fHadronisation = flag;}
    virtual void SetPatchOmegaDalitz(Int_t flag = 1) {fPatchOmegaDalitz = flag;}
    virtual void SetDecayerExodus(Int_t flag = 1) {fDecayerExodus = flag;}
    virtual void SetReadFromFile(const Text_t *filname) {fkFileName = filname;  fReadFromFile = 1;}    
    virtual void SetReadLHEF(const Text_t *filename) {fkNameLHEF = filename; fReadLHEF = 1;}    

    //
    // Pile-up
    //
    // Get interaction rate for pileup studies
    virtual void    SetInteractionRate(Float_t rate,Float_t timewindow = 90.e-6);
    virtual Float_t GetInteractionRate() const {return fInteractionRate;}
    // get cross section of process
    virtual Float_t GetXsection() const {return fXsection;}
    // get triggered jets
    void GetJets(Int_t& njets, Int_t& ntrig, Float_t jets[4][10]);
    void RecJetsUA1(Int_t& njets, Float_t jets[4][50]);
    void SetPycellParameters(Float_t etamax = 2., Int_t neta = 274, Int_t nphi = 432,
			     Float_t thresh = 0., Float_t etseed = 4.,
			     Float_t minet = 10., Float_t r = 1.);
    
  void LoadEvent(AliStack* stack, Int_t flag = 0, Int_t reHadr = 0);
  void LoadEvent(const TObjArray* stack, Int_t flag = 0, Int_t reHadr = 0);
    // Getters
    virtual Process_t    GetProcess() const {return fProcess;}
    virtual StrucFunc_t  GetStrucFunc() const {return fStrucFunc;}
    virtual void         GetPtHard(Float_t& ptmin, Float_t& ptmax) const
	{ptmin = fPtHardMin; ptmax = fPtHardMax;}
    virtual void         GetNuclei(Int_t&  a1, Int_t& a2) const
	{a1 = fAProjectile; a2 = fATarget;}
    virtual void         GetJetEtRange(Float_t& etamin, Float_t& etamax) const
	{etamin = fEtaMinJet; etamax = fEtaMaxJet;}
    virtual void         GetJetPhiRange(Float_t& phimin, Float_t& phimax) const
	{phimin = fPhiMinJet*180./TMath::Pi(); phimax = fPhiMaxJet*180/TMath::Pi();}
    virtual void         GetGammaEtaRange(Float_t& etamin, Float_t& etamax) const
	{etamin = fEtaMinGamma; etamax = fEtaMaxGamma;}
    virtual void         GetGammaPhiRange(Float_t& phimin, Float_t& phimax) const
	{phimin = fPhiMinGamma*180./TMath::Pi(); phimax = fPhiMaxGamma*180./TMath::Pi();}
    //
    Bool_t CheckDetectorAcceptance(Float_t phi, Float_t eta, Int_t iparticle);
    Bool_t IsInEMCAL (Float_t phi, Float_t eta) const;
    Bool_t IsInPHOS  (Float_t phi, Float_t eta, Int_t iparticle) ;
    Bool_t IsInBarrel(Float_t eta) const;
    Bool_t IsFromHeavyFlavor(Int_t ipart);
    //
    virtual void FinishRun();
    Bool_t CheckTrigger(const TParticle* jet1, const TParticle* jet2);
    //Used in some processes to selected child properties
    Bool_t CheckKinematicsOnChild();
    void     GetSubEventTime();

    void SetTuneForDiff(Bool_t a=kTRUE) {fkTuneForDiff=a;}
    AliDecayer * GetDecayer(){return fDecayer;}

 protected:
    // adjust the weight from kinematic cuts
    void     AdjustWeights() const;
    Int_t    GenerateMB();
    void     MakeHeader();    
    void     GeneratePileup();
    Process_t   fProcess;           //Process type
    Int_t       fItune;             // Pythia tune > 6.4
    StrucFunc_t fStrucFunc;         //Structure Function
    Float_t     fKineBias;          //!Bias from kinematic selection
    Int_t       fTrials;            //!Number of trials for current event
    Int_t       fTrialsRun;         //!Number of trials for run
    Float_t     fQ;                 //Mean Q
    Float_t     fX1;                //Mean x1
    Float_t     fX2;                //Mean x2
    Float_t     fEventTime;         //Time of the subevent
    Float_t     fInteractionRate;   //Interaction rate (set by user)
    Float_t     fTimeWindow;        //Time window for pileup events (set by user)
    Int_t       fCurSubEvent;       //Index of the current sub-event
    TArrayF     *fEventsTime;       //Subevents time for pileup
    Int_t       fNev;               //Number of events 
    Int_t       fFlavorSelect;      //Heavy Flavor Selection
    Float_t     fXsection;          //Cross-section
    AliPythia   *fPythia;           //!Pythia 
    Float_t     fWeightPower;       //power for cross section weights; 0 means no reweighting
    Float_t     fPtHardMin;         //lower pT-hard cut 
    Float_t     fPtHardMax;         //higher pT-hard cut
    Float_t     fYHardMin;          //lower  y-hard cut 
    Float_t     fYHardMax;          //higher y-hard cut
    Int_t       fGinit;             //initial state gluon radiation
    Int_t       fGfinal;            //final state gluon radiation
    Int_t       fCRoff;             //color reconnection off in the pythia6 annealying model
    Int_t       fHadronisation;     //hadronisation
    Bool_t      fPatchOmegaDalitz;  //flag for omega dalitz decay patch
    Bool_t      fDecayerExodus;     //flag for exodus decayer
    Int_t       fNpartons;          //Number of partons before hadronisation
    Int_t       fReadFromFile;      //read partons from file
    Int_t       fReadLHEF;          //read lhef file
    Int_t       fQuench;            //Flag for quenching
    Float_t     fQhat;              //Transport coefficient (GeV^2/fm)
    Float_t     fLength;            //Medium length (fm)
    Float_t     fpyquenT;           //Pyquen initial temperature 
    Float_t     fpyquenTau;         //Pyquen initial proper time
    Int_t       fpyquenNf;          //Pyquen number of flavours into the game
    Int_t       fpyquenEloss;       //Pyquen type of energy loss 
    Int_t       fpyquenAngle;       //Pyquen radiation angle for gluons
    Float_t     fImpact;            //Impact parameter for quenching simulation (q-pythia) 
    Float_t     fPtKick;            //Transverse momentum kick
    Bool_t      fFullEvent;         //!Write Full event if true
    AliDecayer  *fDecayer;          //!Pointer to the decayer instance
    Int_t       fDebugEventFirst;   //!First event to debug
    Int_t       fDebugEventLast;    //!Last  event to debug
    Float_t     fEtMinJet;          //Minimum et of triggered Jet
    Float_t     fEtMaxJet;          //Maximum et of triggered Jet
    Float_t     fEtaMinJet;         //Minimum eta of triggered Jet
    Float_t     fEtaMaxJet;         //Maximum eta of triggered Jet
    Float_t     fPhiMinJet;         //Minimum phi of triggered Jet
    Float_t     fPhiMaxJet;         //Maximum phi of triggered Jet
    Int_t       fJetReconstruction; //Jet Reconstruction mode 
    Float_t     fEtaMinGamma;       // Minimum eta of triggered gamma
    Float_t     fEtaMaxGamma;       // Maximum eta of triggered gamma
    Float_t     fPhiMinGamma;       // Minimum phi of triggered gamma
    Float_t     fPhiMaxGamma;       // Maximum phi of triggered gamma
    Bool_t      fUseYCutHQ;         // siwtch for using y cut for heavy quarks
    Float_t     fYMinHQ;            // Minimum y of triggered heavy quarks
    Float_t     fYMaxHQ;            // Maximum y of triggered heavy quarks
    Float_t     fPycellEtaMax;      // Max. eta for Pycell 
    Int_t       fPycellNEta;        // Number of eta bins for Pycell 
    Int_t       fPycellNPhi;        // Number of phi bins for Pycell
    Float_t	fPycellThreshold;   // Pycell threshold
    Float_t 	fPycellEtSeed;      // Pycell seed
    Float_t	fPycellMinEtJet;    // Pycell min. jet et
    Float_t	fPycellMaxRadius;   // Pycell cone radius
    StackFillOpt_t fStackFillOpt;   // Stack filling with all particles with
                                    // that flavour or only with selected
                                    // parents and their decays
    Bool_t fFeedDownOpt;            // Option to set feed down from higher
                                    // quark families (e.g. b->c)
    Bool_t  fFragmentation;         // Option to activate fragmentation by Pythia
    Bool_t  fSetNuclei;             // Flag indicating that SetNuclei has been called
    Bool_t  fUseNuclearPDF;         // flag if nuclear pdf should be applied
    Bool_t  fUseLorentzBoost;       // flag if lorentz boost should be applied
    Bool_t  fNewMIS;                // Flag for the new multipple interactions scenario
    Bool_t  fHFoff;                 // Flag for switching heafy flavor production off
    Int_t   fNucPdf;                // Nuclear pdf 0: EKS98 1: EPS08
    Int_t   fTriggerParticle;       // Trigger on this particle ...
    Float_t fTriggerEta;            // .. within |eta| < fTriggerEta
    Float_t fTriggerY;              // .. within |y|   < fTriggerEta
    Float_t fTriggerEtaMin;         // .. within fTriggerEtaMin < eta < fTriggerEta
    Float_t fTriggerMinPt;          // .. within pt > fTriggerMinPt
    Float_t fTriggerMaxPt;          // .. within pt < fTriggerMaxPt
    Int_t       fTriggerMultiplicity;       // Trigger on events with a minimum charged multiplicity
    Float_t     fTriggerMultiplicityEta;    // in a given eta range
    Float_t     fTriggerMultiplicityEtaMin;    // in a given eta min
    Float_t     fTriggerMultiplicityEtaMax;    // in a given eta max
    Float_t     fTriggerMultiplicityPtMin;  // above this pT 
    CountMode_t fCountMode;         // Options for counting when the event will be finished.     
    // fCountMode = kCountAll         --> All particles that end up in the
    //                                    stack are counted
    // fCountMode = kCountParents     --> Only selected parents are counted
    // fCountMode = kCountTrackabless --> Only particles flagged for tracking
    //                                     are counted
    //
    //

    AliGenPythiaEventHeader* fHeader;  //! Event header
    AliRunLoader*            fRL;      //! Run Loader
    const Text_t* fkFileName;          //! Name of file to read from
    const Text_t* fkNameLHEF;          //! Name of lhef file to read from
    Bool_t fFragPhotonInCalo; // Option to ask for Fragmentation Photon in calorimeters acceptance
    Bool_t fHadronInCalo;     // Option to ask for hadron (not pi0) in calorimeters acceptance
    Bool_t fPi0InCalo;        // Option to ask for Pi0 in calorimeters acceptance
    Bool_t fEtaInCalo;        // Option to ask for Eta in calorimeters acceptance
    Bool_t fPhotonInCalo;     // Option to ask for Photon in calorimeter acceptance (not in use)
    Bool_t fDecayPhotonInCalo;// Option to ask for Decay Photon in calorimeter acceptance
    Bool_t fForceNeutralMeson2PhotonDecay; // Option to ask for Pi0/Eta in calorimeters acceptance when decay into 2 photons
    Bool_t fEleInCalo;        // Option to ask for Electron in EMCAL acceptance
    Bool_t fEleInEMCAL;       // Option to ask for Electron in EMCAL acceptance (not in use)
    Bool_t fCheckBarrel;      // Option to ask for FragPhoton or Pi0 or Eta or gamma decays in central barrel acceptance
    Bool_t fCheckEMCAL;       // Option to ask for FragPhoton or Pi0 or Eta or gamma decays in calorimeters EMCAL acceptance
    Bool_t fCheckPHOS;        // Option to ask for FragPhoton or Pi0 or Eta or gamma decays in calorimeters PHOS acceptance
    Bool_t fCheckPHOSeta;     // Option to ask for rotate event particles in phi to have in PHOS acceptance a requested particle that previously had the good eta
    Int_t  fPHOSRotateCandidate; // Internal member to select the particle candidate to trigger the event phi rotation, to put it in PHOS phi acceptance
    Float_t fTriggerParticleMinPt; // Minimum momentum of Fragmentation Photon or Pi0 or other hadron
    Float_t fPhotonMinPt;          // Minimum momentum of Photon  (not in use)
    Float_t fElectronMinPt;        // Minimum momentum of Electron (not in use) 
    //Calorimeters eta-phi acceptance 
    Float_t fPHOSMinPhi;           // Minimum phi PHOS, degrees
    Float_t fPHOSMaxPhi;           // Maximum phi PHOS, degrees
    Float_t fPHOSEta;              // Minimum eta PHOS, coverage delta eta
    Float_t fEMCALMinPhi;          // Minimum phi EMCAL, degrees
    Float_t fEMCALMaxPhi;          // Maximum phi EMCAL, degrees
    Float_t fEMCALEta;             // Maximum eta EMCAL, coverage delta eta

    Bool_t fkTuneForDiff;    // Pythia tune 
    Int_t  fProcDiff;
 private:
    AliGenPythia(const AliGenPythia &Pythia);
    AliGenPythia & operator=(const AliGenPythia & rhs);


    Bool_t CheckDiffraction();
    Bool_t GetWeightsDiffraction(Double_t M, Double_t &Mmin, Double_t &Mmax, 
					       Double_t &wSD, Double_t &wDD, Double_t &wND);

    ClassDef(AliGenPythia, 15) // AliGenerator interface to Pythia
};
#endif