small update
[u/mrichter/AliRoot.git] / EVGEN / AliGenParam.cxx
index 3ca54db..de448cb 100644 (file)
  * provided "as is" without express or implied warranty.                  *
  **************************************************************************/
 
-/*
-$Log$
-Revision 1.28  2001/03/09 13:01:41  morsch
-- enum constants for paramterisation type (particle family) moved to AliGen*lib.h
-- use AliGenGSIlib::kUpsilon, AliGenPHOSlib::kEtaPrime to access the constants
-
-Revision 1.27  2001/02/02 15:21:10  morsch
-Set high water mark after last particle.
-Use Vertex() method for Vertex.
-
-Revision 1.26  2000/12/21 16:24:06  morsch
-Coding convention clean-up
-
-Revision 1.25  2000/11/30 07:12:50  alibrary
-Introducing new Rndm and QA classes
-
-Revision 1.24  2000/10/18 19:11:27  hristov
-Division by zero fixed
-
-Revision 1.23  2000/10/02 21:28:06  fca
-Removal of useless dependecies via forward declarations
-
-Revision 1.22  2000/09/12 14:14:55  morsch
-Call fDecayer->ForceDecay() at the beginning of Generate().
-
-Revision 1.21  2000/09/08 15:39:01  morsch
-Handle the case fForceDecay=all during the generation, i.e. select all secondaries.
-
-Revision 1.20  2000/09/06 14:35:44  morsch
-Use AliDecayerPythia for particle decays.
-
-Revision 1.19  2000/07/11 18:24:56  fca
-Coding convention corrections + few minor bug fixes
+/* $Id$ */
 
-Revision 1.18  2000/06/29 21:08:27  morsch
-All paramatrisation libraries derive from the pure virtual base class AliGenLib.
-This allows to pass a pointer to a library directly to AliGenParam and avoids the
-use of function pointers in Config.C.
+// Class to generate particles from using paramtrized pT and y distributions.
+// Distributions are obtained from pointer to object of type AliGenLib.
+// (For example AliGenMUONlib)
+// Decays are performed using Pythia.
+// andreas.morsch@cern.ch
 
-Revision 1.17  2000/06/09 20:33:30  morsch
-All coding rule violations except RS3 corrected
-
-Revision 1.16  2000/05/02 07:51:31  morsch
-- Control precision of pT sampling TF1::SetNpx(..)
-- Correct initialisation of child-cuts in all constructors.
-- Most coding rule violations corrected.
-
-Revision 1.15  2000/04/03 15:42:12  morsch
-Cuts on primary particles are separated from those on the decay products. Methods
-SetChildMomentumRange, SetChildPtRange, SetChildPhiRange, SetChildThetaRange added.
-
-Revision 1.14  1999/11/09 07:38:48  fca
-Changes for compatibility with version 2.23 of ROOT
-
-Revision 1.13  1999/11/04 11:30:31  fca
-Correct the logics for SetForceDecay
-
-Revision 1.12  1999/11/03 17:43:20  fca
-New version from G.Martinez & A.Morsch
-
-Revision 1.11  1999/09/29 09:24:14  fca
-Introduction of the Copyright and cvs Log
-
-*/
-
-#include "AliGenParam.h"
-#include "AliDecayerPythia.h"
-#include "AliGenMUONlib.h"
-#include "AliRun.h"
-#include <TParticle.h>
-#include <TParticlePDG.h>
+#include <TCanvas.h>
+#include <TClonesArray.h>
 #include <TDatabasePDG.h>
+#include <TF1.h>
+#include <TH1F.h>
 #include <TLorentzVector.h>
+#include <TMath.h>
+#include <TParticle.h>
+#include <TParticlePDG.h>
+#include <TROOT.h>
+#include <TVirtualMC.h>
 
-#include <TF1.h>
+#include "AliDecayer.h"
+#include "AliGenMUONlib.h"
+#include "AliGenParam.h"
+#include "AliMC.h"
+#include "AliRun.h"
+#include "AliGenEventHeader.h"
 
 ClassImp(AliGenParam)
 
 //------------------------------------------------------------
 
-  //Begin_Html
-  /*
+//Begin_Html
+/*
     <img src="picts/AliGenParam.gif">
-  */
-  //End_Html
+*/
+//End_Html
 
 //____________________________________________________________
-//____________________________________________________________
 AliGenParam::AliGenParam()
+: fPtParaFunc(0),
+       fYParaFunc(0),
+       fIpParaFunc(0),
+  fV2ParaFunc(0),
+       fPtPara(0),
+       fYPara(0),
+  fV2Para(0),
+  fdNdPhi(0),
+       fParam(0),
+       fdNdy0(0.),
+       fYWgt(0.),
+       fPtWgt(0.),
+       fBias(0.),
+       fTrials(0),
+       fDeltaPt(0.01),
+       fSelectAll(kFALSE),
+  fDecayer(0),
+  fForceConv(kFALSE),
+  fKeepParent(kFALSE),
+  fKeepIfOneChildSelected(kFALSE)
 {
-// Deafault constructor
-    fPtPara = 0;
-    fYPara  = 0;
-    fParam  = 0;
-    fAnalog = kAnalog;
-    SetCutOnChild();
-    SetChildMomentumRange();
-    SetChildPtRange();
-    SetChildPhiRange();
-    SetChildThetaRange();  
-    SetDeltaPt();
-//
-// Set random number generator   
-    sRandom = fRandom;
+  // Default constructor
 }
-
-AliGenParam::AliGenParam(Int_t npart, AliGenLib * Library,  Int_t param, char* tname):AliGenerator(npart)
+//____________________________________________________________
+AliGenParam::AliGenParam(Int_t npart, const AliGenLib * Library,  Int_t param, const char* tname)
+    :AliGenMC(npart),
+     fPtParaFunc(Library->GetPt(param, tname)),
+     fYParaFunc (Library->GetY (param, tname)),
+     fIpParaFunc(Library->GetIp(param, tname)),
+   fV2ParaFunc(Library->GetV2(param, tname)),
+     fPtPara(0),
+     fYPara(0),
+   fV2Para(0),
+   fdNdPhi(0),
+     fParam(param),
+     fdNdy0(0.),
+     fYWgt(0.),
+     fPtWgt(0.),
+     fBias(0.),
+     fTrials(0),
+     fDeltaPt(0.01),
+     fSelectAll(kFALSE),
+   fDecayer(0),
+   fForceConv(kFALSE),
+   fKeepParent(kFALSE),
+   fKeepIfOneChildSelected(kFALSE)
 {
-// Constructor using number of particles parameterisation id and library
-    
-    fPtParaFunc = Library->GetPt(param, tname);
-    fYParaFunc  = Library->GetY (param, tname);
-    fIpParaFunc = Library->GetIp(param, tname);
-    
-    fPtPara = 0;
-    fYPara  = 0;
-    fParam  = param;
+  // Constructor using number of particles parameterisation id and library
+    fName = "Param";
+    fTitle= "Particle Generator using pT and y parameterisation";
     fAnalog = kAnalog;
-    fChildSelect.Set(5);
-    for (Int_t i=0; i<5; i++) fChildSelect[i]=0;
     SetForceDecay();
-    SetCutOnChild();
-    SetChildMomentumRange();
-    SetChildPtRange();
-    SetChildPhiRange();
-    SetChildThetaRange(); 
-    SetDeltaPt(); 
-//
-// Set random number generator   
-    sRandom = fRandom;
 }
-
 //____________________________________________________________
-
-AliGenParam::AliGenParam(Int_t npart, Int_t param, char* tname):AliGenerator(npart)
+AliGenParam::AliGenParam(Int_t npart, Int_t param, const char* tname, const char* name):
+    AliGenMC(npart),
+    fPtParaFunc(0),
+    fYParaFunc (0),
+    fIpParaFunc(0),
+  fV2ParaFunc(0),
+    fPtPara(0),
+    fYPara(0),
+  fV2Para(0),
+  fdNdPhi(0),
+    fParam(param),
+    fdNdy0(0.),
+    fYWgt(0.),
+    fPtWgt(0.),
+    fBias(0.),
+    fTrials(0),
+    fDeltaPt(0.01),
+    fSelectAll(kFALSE),
+  fDecayer(0),
+  fForceConv(kFALSE),
+  fKeepParent(kFALSE),
+  fKeepIfOneChildSelected(kFALSE)
 {
-// Constructor using parameterisation id and number of particles
-//      
+  // Constructor using parameterisation id and number of particles
+  //
+    fName = name;
+    fTitle= "Particle Generator using pT and y parameterisation";
+      
     AliGenLib* pLibrary = new AliGenMUONlib();
     fPtParaFunc = pLibrary->GetPt(param, tname);
     fYParaFunc  = pLibrary->GetY (param, tname);
     fIpParaFunc = pLibrary->GetIp(param, tname);
+  fV2ParaFunc = pLibrary->GetV2(param, tname);
     
-    fPtPara = 0;
-    fYPara  = 0;
-    fParam  = param;
     fAnalog = kAnalog;
     fChildSelect.Set(5);
     for (Int_t i=0; i<5; i++) fChildSelect[i]=0;
@@ -169,24 +149,42 @@ AliGenParam::AliGenParam(Int_t npart, Int_t param, char* tname):AliGenerator(npa
     SetChildPtRange();
     SetChildPhiRange();
     SetChildThetaRange(); 
-    SetDeltaPt(); 
 }
+//____________________________________________________________
 
 AliGenParam::AliGenParam(Int_t npart, Int_t param,
-                         Double_t (*PtPara) (Double_t*, Double_t*),
-                         Double_t (*YPara ) (Double_t* ,Double_t*),
+                         Double_t (*PtPara) (const Double_t*, const Double_t*),
+                         Double_t (*YPara ) (const Double_t* ,const Double_t*),
+                         Double_t (*V2Para) (const Double_t* ,const Double_t*),
                         Int_t    (*IpPara) (TRandom *))                 
-    :AliGenerator(npart)
+    :AliGenMC(npart),
+     
+     fPtParaFunc(PtPara),
+     fYParaFunc(YPara),
+     fIpParaFunc(IpPara),
+   fV2ParaFunc(V2Para),
+     fPtPara(0),
+     fYPara(0),
+   fV2Para(0),
+   fdNdPhi(0),
+     fParam(param),
+     fdNdy0(0.),
+     fYWgt(0.),
+     fPtWgt(0.),
+     fBias(0.),
+     fTrials(0),
+     fDeltaPt(0.01),
+     fSelectAll(kFALSE),
+  fDecayer(0),
+  fForceConv(kFALSE),
+  fKeepParent(kFALSE),
+  fKeepIfOneChildSelected(kFALSE)
 {
-// Constructor
-// Gines Martinez 1/10/99 
-    fPtParaFunc = PtPara; 
-    fYParaFunc  = YPara;  
-    fIpParaFunc = IpPara;
-//  
-    fPtPara = 0;
-    fYPara  = 0;
-    fParam  = param;
+  // Constructor
+  // Gines Martinez 1/10/99 
+    fName = "Param";
+    fTitle= "Particle Generator using pT and y parameterisation";
+
     fAnalog = kAnalog;
     fChildSelect.Set(5);
     for (Int_t i=0; i<5; i++) fChildSelect[i]=0;
@@ -196,57 +194,306 @@ AliGenParam::AliGenParam(Int_t npart, Int_t param,
     SetChildPtRange();
     SetChildPhiRange();
     SetChildThetaRange();  
-    SetDeltaPt();
-}
-
-
-AliGenParam::AliGenParam(const AliGenParam & Paramd)
-{
-// copy constructor
 }
 
 //____________________________________________________________
 AliGenParam::~AliGenParam()
 {
-// Destructor
+  // Destructor
     delete  fPtPara;
     delete  fYPara;
+  delete  fV2Para;
+  delete  fdNdPhi;
+}
+
+//-------------------------------------------------------------------
+TVector3 AliGenParam::OrthogonalVector(TVector3 &inVec){
+  double abc[]={inVec.x(), inVec.y(), inVec.z()}; 
+  double xyz[]={1,1,1};
+  int solvDim=0;
+  double tmp=abc[0];
+  for(int i=0; i<3; i++)
+    if(fabs(abc[i])>tmp){
+      solvDim=i;
+      tmp=fabs(abc[i]);
+    }
+  xyz[solvDim]=(-abc[(1+solvDim)%3]-abc[(2+solvDim)%3])/abc[(0+solvDim)%3];
+  
+  TVector3 res(xyz[0],xyz[1],xyz[2]);
+  return res;
+}
+
+void AliGenParam::RotateVector(Double_t *pin, Double_t *pout, Double_t costheta, Double_t sintheta,
+    Double_t cosphi, Double_t sinphi)
+{
+  // Perform rotation
+  pout[0] = pin[0]*costheta*cosphi-pin[1]*sinphi+pin[2]*sintheta*cosphi;
+  pout[1] = pin[0]*costheta*sinphi+pin[1]*cosphi+pin[2]*sintheta*sinphi;
+  pout[2] = -1.0  * pin[0] * sintheta + pin[2] * costheta;
+  return;
+}
+
+double AliGenParam::ScreenFunction1(double screenVariable){
+  if(screenVariable>1)
+    return 42.24 - 8.368 * log(screenVariable + 0.952);
+  else
+    return 42.392 - screenVariable * (7.796 - 1.961 * screenVariable);
+}
+
+double AliGenParam::ScreenFunction2(double screenVariable){
+  if(screenVariable>1)
+    return 42.24 - 8.368 * log(screenVariable + 0.952);
+  else
+    return 41.405 - screenVariable * (5.828 - 0.8945 * screenVariable);
+}
+
+double AliGenParam::RandomEnergyFraction(double Z, double photonEnergy){
+  double aZ=Z/137.036;
+  double epsilon ;
+  double epsilon0Local = 0.000511 / photonEnergy ;
+
+  // Do it fast if photon energy < 2. MeV
+  if (photonEnergy < 0.002 )
+    {
+      epsilon = epsilon0Local + (0.5 - epsilon0Local) * fRandom->Rndm();
+    }
+  else
+    {
+      double fZ = 8*log(Z)/3;
+  double fcZ=(aZ*aZ)*(1/(1+aZ*aZ)+0.20206-0.0368*aZ*aZ+0.0083*aZ*aZ*aZ);
+      if (photonEnergy > 0.050) fZ += 8*fcZ;
+      
+      // Limits of the screening variable
+      double screenFactor = 136. * epsilon0Local / pow (Z,1/3);
+      double screenMax = exp ((42.24 - fZ)/8.368) - 0.952 ;
+      double screenMin = std::min(4.*screenFactor,screenMax) ;
+
+      // Limits of the energy sampling
+      double epsilon1 = 0.5 - 0.5 * sqrt(1. - screenMin / screenMax) ;
+      double epsilonMin = std::max(epsilon0Local,epsilon1);
+      double epsilonRange = 0.5 - epsilonMin ;
+
+      // Sample the energy rate of the created electron (or positron)
+      double screen;
+      double gReject ;
+
+      double f10 = ScreenFunction1(screenMin) - fZ;
+      double f20 = ScreenFunction2(screenMin) - fZ;
+      double normF1 = std::max(f10 * epsilonRange * epsilonRange,0.);
+      double normF2 = std::max(1.5 * f20,0.);
+
+      do 
+       {
+         if (normF1 / (normF1 + normF2) > fRandom->Rndm() )
+           {
+             epsilon = 0.5 - epsilonRange * pow(fRandom->Rndm(), 0.333333) ;
+             screen = screenFactor / (epsilon * (1. - epsilon));
+             gReject = (ScreenFunction1(screen) - fZ) / f10 ;
+           }
+         else
+           {
+             epsilon = epsilonMin + epsilonRange * fRandom->Rndm();
+             screen = screenFactor / (epsilon * (1 - epsilon));
+             gReject = (ScreenFunction2(screen) - fZ) / f20 ;
+           }
+       } while ( gReject < fRandom->Rndm() );
+    
+    }   //  End of epsilon sampling
+  return epsilon;
+}
+
+double AliGenParam::RandomPolarAngle(){
+  double u;
+  const double a1 = 0.625;
+  double a2 = 3. * a1;
+  //  double d = 27. ;
+
+  //  if (9. / (9. + d) > fRandom->Rndm())
+  if (0.25 > fRandom->Rndm())
+    {
+      u = - log(fRandom->Rndm() * fRandom->Rndm()) / a1 ;
+    }
+  else
+    {
+      u = - log(fRandom->Rndm() * fRandom->Rndm()) / a2 ;
+    }
+  return u*0.000511;
+}
+  
+Double_t AliGenParam::RandomMass(Double_t mh){
+  while(true){
+    double y=fRandom->Rndm();
+    double mee=2*0.000511*TMath::Power(2*0.000511/mh,-y); //inverse of the enveloping cumulative distribution
+    double apxkw=2.0/3.0/137.036/TMath::Pi()/mee; //enveloping probability density
+    double val=fRandom->Uniform(0,apxkw);
+    double kw=apxkw*sqrt(1-4*0.000511*0.000511/mee/mee)*(1+2*0.000511*0.000511/mee/mee)*1*1*TMath::Power(1-mee*mee/mh/mh,3);
+    if(val<kw)
+      return mee;
+  }
+}
+
+Int_t AliGenParam::VirtualGammaPairProduction(TClonesArray *particles, Int_t nPart)
+{
+  Int_t nPartNew=nPart;
+  for(int iPart=0; iPart<nPart; iPart++){      
+    TParticle *gamma = (TParticle *) particles->At(iPart);
+    if(gamma->GetPdgCode()!=220000) continue;
+    if(gamma->Pt()<0.002941) continue;  //approximation of kw in AliGenEMlib is 0 below 0.002941
+    double mass=RandomMass(gamma->Pt());
+
+    // lepton pair kinematics in virtual photon rest frame 
+    double Ee=mass/2;
+    double Pe=TMath::Sqrt((Ee+0.000511)*(Ee-0.000511));
+
+    double costheta = (2.0 * gRandom->Rndm()) - 1.;
+    double sintheta = TMath::Sqrt((1. + costheta) * (1. - costheta));
+    double phi      = 2.0 * TMath::ACos(-1.) * gRandom->Rndm();
+    double sinphi   = TMath::Sin(phi);
+    double cosphi   = TMath::Cos(phi);
+    
+    // momentum vectors of leptons in virtual photon rest frame
+    Double_t pProd1[3] = {Pe * sintheta * cosphi,
+                         Pe * sintheta * sinphi,
+                         Pe * costheta};
+
+    Double_t pProd2[3] = {-1.0 * Pe * sintheta * cosphi,
+                         -1.0 * Pe * sintheta * sinphi,
+                         -1.0 * Pe * costheta}; 
+
+    // lepton 4-vectors in properly rotated virtual photon rest frame
+    Double_t pRot1[3] = {0.};
+    RotateVector(pProd1, pRot1, costheta, -sintheta, -cosphi, -sinphi);
+    Double_t pRot2[3] = {0.};
+    RotateVector(pProd2, pRot2, costheta, -sintheta, -cosphi, -sinphi); 
+
+    TLorentzVector e1V4(pRot1[0],pRot1[1],pRot1[2],Ee);
+    TLorentzVector e2V4(pRot2[0],pRot2[1],pRot2[2],Ee);
+  
+    TVector3 boost(gamma->Px(),gamma->Py(),gamma->Pz());
+    boost*=1/sqrt(gamma->P()*gamma->P()+mass*mass);
+    e1V4.Boost(boost);
+    e2V4.Boost(boost);
+
+    TLorentzVector vtx;
+    gamma->ProductionVertex(vtx);
+    new((*particles)[nPartNew]) TParticle(11, gamma->GetStatusCode(), iPart+1, -1, 0, 0, e1V4, vtx);
+    nPartNew++;
+    new((*particles)[nPartNew]) TParticle(-11, gamma->GetStatusCode(), iPart+1, -1, 0, 0, e2V4, vtx);
+    nPartNew++;
+  }
+  return nPartNew;
+}
+
+Int_t AliGenParam::ForceGammaConversion(TClonesArray *particles, Int_t nPart)
+{
+  //based on: http://geant4.cern.ch/G4UsersDocuments/UsersGuides/PhysicsReferenceManual/html/node27.html
+  //     and: http://geant4.cern.ch/G4UsersDocuments/UsersGuides/PhysicsReferenceManual/html/node58.html
+  //     and: G4LivermoreGammaConversionModel.cc
+  Int_t nPartNew=nPart;
+  for(int iPart=0; iPart<nPart; iPart++){      
+    TParticle *gamma = (TParticle *) particles->At(iPart);
+    if(gamma->GetPdgCode()!=22) continue;
+    if(gamma->Energy()<0.001022) continue;
+    TVector3 gammaV3(gamma->Px(),gamma->Py(),gamma->Pz());
+    double frac=RandomEnergyFraction(1,gamma->Energy());
+    double Ee1=frac*gamma->Energy();
+    double Ee2=(1-frac)*gamma->Energy();
+    double Pe1=sqrt((Ee1+0.000511)*(Ee1-0.000511));
+    double Pe2=sqrt((Ee2+0.000511)*(Ee2-0.000511));
+    
+    TVector3 rotAxis(OrthogonalVector(gammaV3));
+    Float_t az=fRandom->Uniform(TMath::Pi()*2);
+    rotAxis.Rotate(az,gammaV3);
+    TVector3 e1V3(gammaV3);
+    double u=RandomPolarAngle();
+    e1V3.Rotate(u/Ee1,rotAxis);
+    e1V3=e1V3.Unit();
+    e1V3*=Pe1;
+    TVector3 e2V3(gammaV3);
+    e2V3.Rotate(-u/Ee2,rotAxis);
+    e2V3=e2V3.Unit();
+    e2V3*=Pe2;
+    // gamma = new TParticle(*gamma);
+    // particles->RemoveAt(iPart);
+    gamma->SetFirstDaughter(nPartNew+1);
+    gamma->SetLastDaughter(nPartNew+2);
+    // new((*particles)[iPart]) TParticle(*gamma);
+    // delete gamma;
+
+    TLorentzVector vtx;
+    gamma->ProductionVertex(vtx);
+    new((*particles)[nPartNew]) TParticle(11, gamma->GetStatusCode(), iPart+1, -1, 0, 0, TLorentzVector(e1V3,Ee1), vtx);
+    nPartNew++;
+    new((*particles)[nPartNew]) TParticle(-11, gamma->GetStatusCode(), iPart+1, -1, 0, 0, TLorentzVector(e2V3,Ee2), vtx);
+    nPartNew++;
+  }
+  return nPartNew;
 }
 
 //____________________________________________________________
 void AliGenParam::Init()
 {
-// Initialisation
+  // Initialisation
 
-    fDecayer = new AliDecayerPythia();
+    if (TVirtualMC::GetMC()) fDecayer = TVirtualMC::GetMC()->GetDecayer();
   //Begin_Html
   /*
     <img src="picts/AliGenParam.gif">
   */
   //End_Html
-    fPtPara = new TF1("Pt-Parametrization",fPtParaFunc,fPtMin,fPtMax,0);
-//  Set representation precision to 10 MeV
-    Int_t npx= Int_t((fPtMax-fPtMin)/fDeltaPt);
+    char name[256];
+    snprintf(name, 256, "pt-parameterisation for %s", GetName());
+    
+    if (fPtPara) fPtPara->Delete();
+    fPtPara = new TF1(name, fPtParaFunc, fPtMin, fPtMax,0);
+    gROOT->GetListOfFunctions()->Remove(fPtPara);
+  //  Set representation precision to 10 MeV
+    Int_t npx= Int_t((fPtMax - fPtMin) / fDeltaPt);
     
     fPtPara->SetNpx(npx);
+
+    snprintf(name, 256, "y-parameterisation  for %s", GetName());
+    if (fYPara) fYPara->Delete();
+    fYPara  = new TF1(name, fYParaFunc, fYMin, fYMax, 0);
+    gROOT->GetListOfFunctions()->Remove(fYPara);
+
+  snprintf(name, 256, "v2-parameterisation for %s", GetName());
+  if (fV2Para) fV2Para->Delete();
+  fV2Para  = new TF1(name, fV2ParaFunc, fPtMin, fPtMax, 0);
+  // fV2Para  = new TF1(name, "2*[0]/(1+TMath::Exp([1]*([2]-x)))-[0]", fPtMin, fPtMax);
+  // fV2Para->SetParameter(0, 0.236910);
+  // fV2Para->SetParameter(1, 1.71122);
+  // fV2Para->SetParameter(2, 0.0827617);
+  //gROOT->GetListOfFunctions()->Remove(fV2Para);  //TR: necessary?
     
-    fYPara  = new TF1("Y -Parametrization",fYParaFunc,fYMin,fYMax,0);
-    TF1* ptPara = new TF1("Pt-Parametrization",fPtParaFunc,0,15,0);
-    TF1* yPara  = new TF1("Y -Parametrization",fYParaFunc,-6,6,0);
+  snprintf(name, 256, "dNdPhi for %s", GetName());
+  if (fdNdPhi) fdNdPhi->Delete();
+  fdNdPhi  = new TF1(name, "1+2*[0]*TMath::Cos(2*(x-[1]))", fPhiMin, fPhiMax);
+  //gROOT->GetListOfFunctions()->Remove(fdNdPhi);  //TR: necessary?
+    
+    snprintf(name, 256, "pt-for-%s", GetName());
+    TF1 ptPara(name ,fPtParaFunc, 0, 15, 0);
+    snprintf(name, 256, "y-for-%s", GetName());
+    TF1 yPara(name, fYParaFunc, -6, 6, 0);
 
-//
-// dN/dy| y=0
+  //
+  // dN/dy| y=0
     Double_t y1=0;
     Double_t y2=0;
     
     fdNdy0=fYParaFunc(&y1,&y2);
-//
-// Integral over generation region
-    Float_t intYS  = yPara ->Integral(fYMin, fYMax);
-    Float_t intPt0 = ptPara->Integral(0,15);
-    Float_t intPtS = ptPara->Integral(fPtMin,fPtMax);
-    Float_t phiWgt=(fPhiMax-fPhiMin)/2./TMath::Pi();
+  //
+  // Integral over generation region
+#if ROOT_VERSION_CODE < ROOT_VERSION(5,99,0)
+    Float_t intYS  = yPara.Integral(fYMin, fYMax,(Double_t*) 0x0,1.e-6);
+    Float_t intPt0 = ptPara.Integral(0,15,(Double_t *) 0x0,1.e-6);
+    Float_t intPtS = ptPara.Integral(fPtMin,fPtMax,(Double_t*) 0x0,1.e-6);
+#else
+    Float_t intYS  = yPara.Integral(fYMin, fYMax,1.e-6);
+    Float_t intPt0 = ptPara.Integral(0,15,1.e-6);
+    Float_t intPtS = ptPara.Integral(fPtMin,fPtMax,1.e-6);
+#endif
+  Float_t phiWgt=(fPhiMax-fPhiMin)/2./TMath::Pi();    //TR: should probably be done differently in case of anisotropic phi...
     if (fAnalog == kAnalog) {
        fYWgt  = intYS/fdNdy0;
        fPtWgt = intPtS/intPt0;
@@ -256,112 +503,97 @@ void AliGenParam::Init()
        fPtWgt = (fPtMax-fPtMin)/intPt0;
        fParentWeight = fYWgt*fPtWgt*phiWgt/fNpart;
     }
-//
-// particle decay related initialization
+  //
+  // particle decay related initialization
     fDecayer->SetForceDecay(fForceDecay);
     fDecayer->Init();
 
-//
-    switch (fForceDecay) 
-    {
-    case kSemiElectronic:
-    case kDiElectron:
-    case kBJpsiDiElectron:
-    case kBPsiPrimeDiElectron:
-       fChildSelect[0]=11;     
-       break;
-    case kSemiMuonic:
-    case kDiMuon:
-    case kBJpsiDiMuon:
-    case kBPsiPrimeDiMuon:
-       fChildSelect[0]=13;
-       break;
-    case kPiToMu:
-       fChildSelect[0]=13;
-       break;
-    case kKaToMu:
-       fChildSelect[0]=13;
-       break;
-    case kHadronicD:
-// Implement me !!
-       break;
-    case kNoDecay:
-       break;
-    case kAll:
-       break;
-    }
+  //
+    AliGenMC::Init();
 }
 
 //____________________________________________________________
 void AliGenParam::Generate()
 {
-//
-// Generate 'npart' of light and heavy mesons (J/Psi, upsilon or phi, Pion,
-// Kaons, Etas, Omegas) and Baryons (proton, antiprotons, neutrons and 
-// antineutrons in the the desired theta, phi and momentum windows; 
-// Gaussian smearing on the vertex is done if selected. 
-// The decay of heavy mesons is done using lujet, 
-//    and the childern particle are tracked by GEANT
-// However, light mesons are directly tracked by GEANT 
-// setting fForceDecay = nodecay (SetForceDecay(nodecay)) 
-//
-//
-//  Reinitialize decayer
-    fDecayer->Init();
-//
+  // 
+  // Generate 1 event (see Generate(Int_t ntimes) for details
+  //
+  GenerateN(1);
+}
+//____________________________________________________________
+void AliGenParam::GenerateN(Int_t ntimes)
+{
+  //
+  // Generate ntimes*'npart' light and heavy mesons (J/Psi, upsilon or phi, Pion,
+  // Kaons, Etas, Omegas) and Baryons (proton, antiprotons, neutrons and 
+  // antineutrons in the the desired theta, phi and momentum windows; 
+  // Gaussian smearing on the vertex is done if selected. 
+  // The decay of heavy mesons is done using lujet, 
+  //    and the childern particle are tracked by GEANT
+  // However, light mesons are directly tracked by GEANT 
+  // setting fForceDecay = nodecay (SetForceDecay(nodecay)) 
+  //
+  //
+  //  Reinitialize decayer
+  fDecayer->SetForceDecay(fForceDecay);
+  fDecayer->Init();
+
+  //
   Float_t polar[3]= {0,0,0};  // Polarisation of the parent particle (for GEANT tracking)
   Float_t origin0[3];         // Origin of the generated parent particle (for GEANT tracking)
+  Float_t time0;              // Time0 of the generated parent particle
   Float_t pt, pl, ptot;       // Transverse, logitudinal and total momenta of the parent particle
   Float_t phi, theta;         // Phi and theta spherical angles of the parent particle momentum
   Float_t p[3], pc[3], 
-          och[3], pch[10][3]; // Momentum, polarisation and origin of the children particles from lujet
-  Float_t ty, xmt;
-  Int_t nt, i, j, kfch[10];
+          och[3];             // Momentum, polarisation and origin of the children particles from lujet
+  Double_t ty, xmt;
+  Int_t nt, i, j;
   Float_t  wgtp, wgtch;
   Double_t dummy;
   static TClonesArray *particles;
   //
-  if(!particles) particles=new TClonesArray("TParticle",1000);
-
-  static TDatabasePDG *pDataBase = new TDatabasePDG();
-  if(!pDataBase) pDataBase = new TDatabasePDG();
+  if(!particles) particles = new TClonesArray("TParticle",1000);
+  
+  TDatabasePDG *pDataBase = TDatabasePDG::Instance();
   //
   Float_t random[6];
  
-// Calculating vertex position per event
+  // Calculating vertex position per event
   for (j=0;j<3;j++) origin0[j]=fOrigin[j];
+  time0 = fTimeOrigin;
   if(fVertexSmear==kPerEvent) {
-//      Rndm(random,6);
-//      for (j=0;j<3;j++) {
-//       origin0[j]+=fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
-//           TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
-//           TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
-//      }
-//    }
       Vertex();
       for (j=0;j<3;j++) origin0[j]=fVertex[j];
+      time0 = fTime;
   }
   
   Int_t ipa=0;
-// Generating fNpart particles
-  while (ipa<fNpart) {
+  
+  // Generating fNpart particles
+  fNprimaries = 0;
+  
+  Int_t nGen = fNpart*ntimes;
+  while (ipa<nGen) {
       while(1) {
-//
-// particle type
+      //
+      // particle type 
          Int_t iPart = fIpParaFunc(fRandom);
+      Int_t iTemp = iPart;
+
+      // custom pdg codes for to destinguish direct photons
+      if(iPart==220000) iPart=22;
+
          fChildWeight=(fDecayer->GetPartialBranchingRatio(iPart))*fParentWeight;          
          TParticlePDG *particle = pDataBase->GetParticle(iPart);
          Float_t am = particle->Mass();
-
+         
          Rndm(random,2);
-//
-// phi
-         phi=fPhiMin+random[0]*(fPhiMax-fPhiMin);
-//
-// y
-         ty=Float_t(TMath::TanH(fYPara->GetRandom()));
-//
-// pT
+      //
+      // y
+         ty = TMath::TanH(fYPara->GetRandom());
+
+      //
+      // pT
          if (fAnalog == kAnalog) {
              pt=fPtPara->GetRandom();
              wgtp=fParentWeight;
@@ -373,17 +605,34 @@ void AliGenParam::Generate()
              wgtch=fChildWeight*fPtParaFunc(& ptd, &dummy);
          }
          xmt=sqrt(pt*pt+am*am);
-      if (TMath::Abs(ty)==1) ty=0;
-         pl=xmt*ty/sqrt(1.-ty*ty);
+         if (TMath::Abs(ty)==1.) {
+             ty=0.;
+             Fatal("AliGenParam", 
+                   "Division by 0: Please check you rapidity range !");
+         }
+      //
+      // phi
+         //      if(!ipa)
+         //phi=fEvPlane; //align first particle of each event with event plane
+         //else{
+       double v2 = fV2Para->Eval(pt);
+       fdNdPhi->SetParameter(0,v2);
+       fdNdPhi->SetParameter(1,fEvPlane);
+       phi=fdNdPhi->GetRandom();
+       //     }
+         
+         pl=xmt*ty/sqrt((1.-ty)*(1.+ty));
          theta=TMath::ATan2(pt,pl);
-// Cut on theta
+      // Cut on theta
          if(theta<fThetaMin || theta>fThetaMax) continue;
          ptot=TMath::Sqrt(pt*pt+pl*pl);
-// Cut on momentum
+      // Cut on momentum
          if(ptot<fPMin || ptot>fPMax) continue;
+      //
          p[0]=pt*TMath::Cos(phi);
          p[1]=pt*TMath::Sin(phi);
          p[2]=pl;
+
          if(fVertexSmear==kPerTrack) {
              Rndm(random,6);
              for (j=0;j<3;j++) {
@@ -391,141 +640,227 @@ void AliGenParam::Generate()
                      fOrigin[j]+fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
                      TMath::Sqrt(-2*TMath::Log(random[2*j+1]));
              }
+             Rndm(random,2);
+             time0 = fTimeOrigin + fOsigma[2]/TMath::Ccgs()*
+               TMath::Cos(2*random[0]*TMath::Pi())*
+               TMath::Sqrt(-2*TMath::Log(random[1]));
          }
          
-// Looking at fForceDecay : 
-// if fForceDecay != none Primary particle decays using 
-// AliPythia and children are tracked by GEANT
-//
-// if fForceDecay == none Primary particle is tracked by GEANT 
-// (In the latest, make sure that GEANT actually does all the decays you want)   
-//
+      // Looking at fForceDecay : 
+      // if fForceDecay != none Primary particle decays using 
+      // AliPythia and children are tracked by GEANT
+      //
+      // if fForceDecay == none Primary particle is tracked by GEANT 
+      // (In the latest, make sure that GEANT actually does all the decays you want)     
+      //
+         Bool_t decayed = kFALSE;
+         
+
          if (fForceDecay != kNoDecay) {
-// Using lujet to decay particle
+       // Using lujet to decay particle
              Float_t energy=TMath::Sqrt(ptot*ptot+am*am);
              TLorentzVector pmom(p[0], p[1], p[2], energy);
              fDecayer->Decay(iPart,&pmom);
-//
-// select decay particles
+       //
+       // select decay particles
              Int_t np=fDecayer->ImportParticles(particles);
+
+       iPart=iTemp;
+       if(iPart==220000){
+         TParticle *gamma = (TParticle *)particles->At(0);
+         gamma->SetPdgCode(iPart);
+         np=VirtualGammaPairProduction(particles,np);
+       }
+       if(fForceConv) np=ForceGammaConversion(particles,np);
+
+             //  Selecting  GeometryAcceptance for particles fPdgCodeParticleforAcceptanceCut;
+             if (fGeometryAcceptance) 
+               if (!CheckAcceptanceGeometry(np,particles)) continue;
              Int_t ncsel=0;
-             for (i = 1; i<np; i++) {
-                 TParticle *  iparticle = (TParticle *) particles->At(i);
-                 Int_t kf = iparticle->GetPdgCode();
-//
-// children
-                 if (ChildSelected(TMath::Abs(kf)) || fForceDecay == kAll)
-                 {
-                     pc[0]=iparticle->Px();
-                     pc[1]=iparticle->Py();
-                     pc[2]=iparticle->Pz();
-                     och[0]=origin0[0]+iparticle->Vx()/10;
-                     och[1]=origin0[1]+iparticle->Vy()/10;
-                     och[2]=origin0[2]+iparticle->Vz()/10;
-                     if (fCutOnChild) {
-                         Float_t ptChild=TMath::Sqrt(pc[0]*pc[0]+pc[1]*pc[1]);
-                         Float_t pChild=TMath::Sqrt(ptChild*ptChild+pc[2]*pc[2]);
-                         Float_t thetaChild=TMath::ATan2(ptChild,pc[2]);
-                         Float_t phiChild=TMath::ATan2(pc[1],pc[0]);
-                         Bool_t childok = 
-                             ((ptChild    > fChildPtMin    && ptChild    <fChildPtMax)      &&
-                              (pChild     > fChildPMin     && pChild     <fChildPMax)       &&
-                              (thetaChild > fChildThetaMin && thetaChild <fChildThetaMax)   &&
-                              (phiChild   > fChildPhiMin   && phiChild   <fChildPhiMax));
-                         if(childok)
-                         {
-                             pch[ncsel][0]=pc[0];
-                             pch[ncsel][1]=pc[1];
-                             pch[ncsel][2]=pc[2];
-                             kfch[ncsel]=kf;
-                             ncsel++;
+             Int_t* pFlag      = new Int_t[np];
+             Int_t* pParent    = new Int_t[np];
+             Int_t* pSelected  = new Int_t[np];
+             Int_t* trackIt    = new Int_t[np];
+
+             for (i=0; i<np; i++) {
+                 pFlag[i]     =  0;
+                 pSelected[i] =  0;
+                 pParent[i]   = -1;
+             }
+             
+             if (np >1) {
+                 decayed = kTRUE;
+                 TParticle* iparticle =  0;
+                 Int_t ipF, ipL;
+                 for (i = 1; i<np ; i++) {
+                     trackIt[i] = 1;
+                     iparticle = (TParticle *) particles->At(i);
+                     Int_t kf = iparticle->GetPdgCode();
+                     Int_t ks = iparticle->GetStatusCode();
+           // flagged particle
+
+                     if (pFlag[i] == 1) {
+                         ipF = iparticle->GetFirstDaughter();
+                         ipL = iparticle->GetLastDaughter();   
+                         if (ipF > 0) for (j=ipF-1; j<ipL; j++) pFlag[j]=1;
+                         continue;
+                     }
+
+           // flag decay products of particles with long life-time (c tau > .3 mum)                  
+                     
+                     if (ks != 1) { 
+             //                          TParticlePDG *particle = pDataBase->GetParticle(kf);
+                         
+                         Double_t lifeTime = fDecayer->GetLifetime(kf);
+             //                          Double_t mass     = particle->Mass();
+             //                          Double_t width    = particle->Width();
+                         if (lifeTime > (Double_t) fMaxLifeTime) {
+                             ipF = iparticle->GetFirstDaughter();
+                             ipL = iparticle->GetLastDaughter();       
+                             if (ipF > 0) for (j=ipF-1; j<ipL; j++) pFlag[j]=1;
+                         } else{
+                             trackIt[i]     = 0;
+                             pSelected[i]   = 1;
+                         }
+                     } // ks==1 ?
+           //
+           // children
+                     
+                     if ((ChildSelected(TMath::Abs(kf)) || fForceDecay == kAll || fSelectAll) && trackIt[i])
+                     {
+                         if (fCutOnChild) {
+                             pc[0]=iparticle->Px();
+                             pc[1]=iparticle->Py();
+                             pc[2]=iparticle->Pz();
+                             Bool_t  childok = KinematicSelection(iparticle, 1);
+                             if(childok) {
+                                 pSelected[i]  = 1;
+                                 ncsel++;
+                             } else {
+                                 if(!fKeepIfOneChildSelected){
+                                   ncsel=-1;
+                                   break;
+                                 }
+                             } // child kine cuts
                          } else {
-                             ncsel=-1;
-                             break;
-                         } // child kine cuts
-                     } else {
-                         pch[ncsel][0]=pc[0];
-                         pch[ncsel][1]=pc[1];
-                         pch[ncsel][2]=pc[2];
-                         kfch[ncsel]=kf;
-                         ncsel++;
-                     } // if child selection
-                 } // select muon
-             } // decay particle loop
+                             pSelected[i]  = 1;
+                             ncsel++;
+                         } // if child selection
+                     } // select muon
+                 } // decay particle loop
+             } // if decay products
+             
              Int_t iparent;
-             if ((fCutOnChild && ncsel >0) || !fCutOnChild){
-                 ipa++;
-//
-// parent
-                 gAlice->
-                     SetTrack(0,-1,iPart,p,origin0,polar,0,kPPrimary,nt,wgtp);
-                 iparent=nt;
-                 gAlice->KeepTrack(nt); 
-                 for (i=0; i< ncsel; i++) {
-                     gAlice->SetTrack(fTrackIt,iparent,kfch[i],
-                                      &pch[i][0],och,polar,
-                                      0,kPDecay,nt,wgtch);
-                     gAlice->KeepTrack(nt); 
+             
+             if (fKeepParent || (fCutOnChild && ncsel >0) || !fCutOnChild){
+         //
+         // Parent
+                 
+                 
+                 PushTrack(0, -1, iPart, p, origin0, polar, time0, kPPrimary, nt, wgtp, ((decayed)? 11 : 1));
+                 pParent[0] = nt;
+                 KeepTrack(nt); 
+                 fNprimaries++;
+                 
+                 //but count is as "generated" particle" only if it produced child(s) within cut
+                 if ((fCutOnChild && ncsel >0) || !fCutOnChild){
+                   ipa++;
                  }
+                 
+         //
+         // Decay Products
+         //              
+                 for (i = 1; i < np; i++) {
+                     if (pSelected[i]) {
+                         TParticle* iparticle = (TParticle *) particles->At(i);
+                         Int_t kf   = iparticle->GetPdgCode();
+                         Int_t ksc  = iparticle->GetStatusCode();
+                         Int_t jpa  = iparticle->GetFirstMother()-1;
+                         
+                         och[0] = origin0[0]+iparticle->Vx();
+                         och[1] = origin0[1]+iparticle->Vy();
+                         och[2] = origin0[2]+iparticle->Vz();
+                         pc[0]  = iparticle->Px();
+                         pc[1]  = iparticle->Py();
+                         pc[2]  = iparticle->Pz();
+                         
+                         if (jpa > -1) {
+                             iparent = pParent[jpa];
+                         } else {
+                             iparent = -1;
+                         }
+                        
+                         PushTrack(fTrackIt * trackIt[i], iparent, kf,
+                                          pc, och, polar,
+                                          time0 + iparticle->T(), kPDecay, nt, wgtch, ksc);
+                         pParent[i] = nt;
+                         KeepTrack(nt); 
+                         fNprimaries++;
+                     } // Selected
+                 } // Particle loop 
              }  // Decays by Lujet
+             particles->Clear();
+             if (pFlag)      delete[] pFlag;
+             if (pParent)    delete[] pParent;
+             if (pSelected)  delete[] pSelected;          
+             if (trackIt)    delete[] trackIt;
          } // kinematic selection
          else  // nodecay option, so parent will be tracked by GEANT (pions, kaons, eta, omegas, baryons)
          {
-           gAlice->
-               SetTrack(fTrackIt,-1,iPart,p,origin0,polar,0,kPPrimary,nt,wgtp);
+           gAlice->GetMCApp()->
+               PushTrack(fTrackIt,-1,iPart,p,origin0,polar,time0,kPPrimary,nt,wgtp, 1);
             ipa++; 
+           fNprimaries++;
          }
          break;
     } // while
   } // event loop
-  gAlice->SetHighWaterMark(nt);
   
-}
+  SetHighWaterMark(nt);
 
-Bool_t AliGenParam::ChildSelected(Int_t ip)
-{
-// True if particle is in list of selected children
-    for (Int_t i=0; i<5; i++)
-    {
-       if (fChildSelect[i]==ip) return kTRUE;
-    }
-    return kFALSE;
+  AliGenEventHeader* header = new AliGenEventHeader("PARAM");
+  header->SetPrimaryVertex(fVertex);
+  header->SetInteractionTime(fTime);
+  header->SetNProduced(fNprimaries);
+  AddHeader(header);
 }
-
-Bool_t AliGenParam::KinematicSelection(TParticle *particle)
+//____________________________________________________________________________________
+Float_t AliGenParam::GetRelativeArea(Float_t ptMin, Float_t ptMax, Float_t yMin, Float_t yMax, Float_t phiMin, Float_t phiMax)
 {
-// Perform kinematic cuts
-    Float_t px=particle->Px();
-    Float_t py=particle->Py();
-    Float_t pz=particle->Pz();
-//
-// momentum cut
-    Float_t p=TMath::Sqrt(px*px+py*py+pz*pz);
-    if (p > fPMax || p < fPMin) 
-    {
-//     printf("\n failed p cut %f %f %f \n",p,fPMin,fPMax);
-       return kFALSE;
-    }
-    Float_t pt=TMath::Sqrt(px*px+py*py);
-    
-//
-// theta cut
-    Float_t  theta = Float_t(TMath::ATan2(Double_t(pt),Double_t(p)));
-    if (theta > fThetaMax || theta < fThetaMin) 
-    {
-//     printf("\n failed theta cut %f %f %f \n",theta,fThetaMin,fThetaMax);
-       return kFALSE;
-    }
-
-    return kTRUE;
+  //
+  // Normalisation for selected kinematic region
+  //
+#if ROOT_VERSION_CODE < ROOT_VERSION(5,99,0)
+  Float_t ratio =  
+    fPtPara->Integral(ptMin,ptMax,(Double_t *)0,1.e-6) / fPtPara->Integral( fPtPara->GetXmin(), fPtPara->GetXmax(),(Double_t *)0,1.e-6) *
+    fYPara->Integral(yMin,yMax,(Double_t *)0,1.e-6)/fYPara->Integral(fYPara->GetXmin(),fYPara->GetXmax(),(Double_t *)0,1.e-6)   *
+    (phiMax-phiMin)/360.;
+#else
+  Float_t ratio =  
+    fPtPara->Integral(ptMin,ptMax,1.e-6) / fPtPara->Integral( fPtPara->GetXmin(), fPtPara->GetXmax(),1.e-6) *
+    fYPara->Integral(yMin,yMax,1.e-6)/fYPara->Integral(fYPara->GetXmin(),fYPara->GetXmax(),1.e-6)   *
+    (phiMax-phiMin)/360.;
+#endif
+  return TMath::Abs(ratio);
 }
 
+//____________________________________________________________________________________
 
-AliGenParam& AliGenParam::operator=(const  AliGenParam& rhs)
+void AliGenParam::Draw( const char * /*opt*/)
 {
-// Assignment operator
-    return *this;
+    //
+    // Draw the pT and y Distributions
+    //
+     TCanvas *c0 = new TCanvas("c0","Canvas 0",400,10,600,700);
+     c0->Divide(2,1);
+     c0->cd(1);
+     fPtPara->Draw();
+     fPtPara->GetHistogram()->SetXTitle("p_{T} (GeV)");     
+     c0->cd(2);
+     fYPara->Draw();
+     fYPara->GetHistogram()->SetXTitle("y");     
 }
 
 
 
+