When calculating a*a-b*b the form (a-b)*(a+b) is usually more numerically stable.
[u/mrichter/AliRoot.git] / EVGEN / AliGenParam.cxx
index 13f4af9..506347f 100644 (file)
  * provided "as is" without express or implied warranty.                  *
  **************************************************************************/
 
-/*
-$Log$
-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.
+/* $Id$ */
 
-Revision 1.17  2000/06/09 20:33:30  morsch
-All coding rule violations except RS3 corrected
+// 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 1.16  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 <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 "AliGenParam.h"
+#include "AliDecayer.h"
 #include "AliGenMUONlib.h"
+#include "AliGenParam.h"
+#include "AliMC.h"
 #include "AliRun.h"
-#include "AliPythia.h"
-#include <TParticle.h>
-#include <TF1.h>
+#include "AliGenEventHeader.h"
 
 ClassImp(AliGenParam)
 
@@ -64,62 +51,74 @@ ClassImp(AliGenParam)
   //End_Html
 
 //____________________________________________________________
-//____________________________________________________________
-AliGenParam::AliGenParam()
-                 :AliGenerator()
+    AliGenParam::AliGenParam():
+       fPtParaFunc(0),
+       fYParaFunc(0),
+       fIpParaFunc(0),
+       fPtPara(0),
+       fYPara(0),
+       fParam(0),
+       fdNdy0(0.),
+       fYWgt(0.),
+       fPtWgt(0.),
+       fBias(0.),
+       fTrials(0),
+       fDeltaPt(0.01),
+       fDecayer(0)
 {
-// Deafault constructor
-    fPtPara = 0;
-    fYPara  = 0;
-    fParam  = jpsi_p;
-    fAnalog = analog;
-    SetCutOnChild();
-    SetChildMomentumRange();
-    SetChildPtRange();
-    SetChildPhiRange();
-    SetChildThetaRange();  
-    SetDeltaPt();
+// Default constructor
 }
-
-AliGenParam::AliGenParam(Int_t npart, AliGenLib * Library,  Param_t param, char* tname):AliGenerator(npart)
+//____________________________________________________________
+AliGenParam::AliGenParam(Int_t npart, AliGenLib * Library,  Int_t param, char* tname)
+    :AliGenMC(npart),
+     fPtParaFunc(Library->GetPt(param, tname)),
+     fYParaFunc (Library->GetY (param, tname)),
+     fIpParaFunc(Library->GetIp(param, tname)),
+     fPtPara(0),
+     fYPara(0),
+     fParam(param),
+     fdNdy0(0.),
+     fYWgt(0.),
+     fPtWgt(0.),
+     fBias(0.),
+     fTrials(0),
+     fDeltaPt(0.01),
+     fDecayer(0)
 {
 // 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;
-    fAnalog = analog;
-    fChildSelect.Set(5);
-    for (Int_t i=0; i<5; i++) fChildSelect[i]=0;
+    fName = "Param";
+    fTitle= "Particle Generator using pT and y parameterisation";
+    fAnalog = kAnalog;
     SetForceDecay();
-    SetCutOnChild();
-    SetChildMomentumRange();
-    SetChildPtRange();
-    SetChildPhiRange();
-    SetChildThetaRange(); 
-    SetDeltaPt(); 
 }
-
 //____________________________________________________________
-
-AliGenParam::AliGenParam(Int_t npart, Param_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),
+    fPtPara(0),
+    fYPara(0),
+    fParam(param),
+    fdNdy0(0.),
+    fYWgt(0.),
+    fPtWgt(0.),
+    fBias(0.),
+    fTrials(0),
+    fDeltaPt(0.01),
+    fDecayer(0)
 {
 // Constructor using parameterisation id and number of particles
-//      
-    AliGenLib* Library = new AliGenMUONlib();
-    fPtParaFunc = Library->GetPt(param, tname);
-    fYParaFunc  = Library->GetY (param, tname);
-    fIpParaFunc = Library->GetIp(param, tname);
+//
+    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);
     
-    fPtPara = 0;
-    fYPara  = 0;
-    fParam  = param;
-    fAnalog = analog;
+    fAnalog = kAnalog;
     fChildSelect.Set(5);
     for (Int_t i=0; i<5; i++) fChildSelect[i]=0;
     SetForceDecay();
@@ -128,25 +127,35 @@ AliGenParam::AliGenParam(Int_t npart, Param_t param, char* tname):AliGenerator(n
     SetChildPtRange();
     SetChildPhiRange();
     SetChildThetaRange(); 
-    SetDeltaPt(); 
 }
+//____________________________________________________________
 
-AliGenParam::AliGenParam(Int_t npart, Param_t param,
-                         Double_t (*PtPara) (Double_t*, Double_t*),
-                         Double_t (*YPara ) (Double_t* ,Double_t*),
-                        Int_t    (*IpPara) ())                  
-    :AliGenerator(npart)
+AliGenParam::AliGenParam(Int_t npart, Int_t param,
+                         Double_t (*PtPara) (const Double_t*, const Double_t*),
+                         Double_t (*YPara ) (const Double_t* ,const Double_t*),
+                        Int_t    (*IpPara) (TRandom *))                 
+    :AliGenMC(npart),
+     
+     fPtParaFunc(PtPara),
+     fYParaFunc(YPara),
+     fIpParaFunc(IpPara),
+     fPtPara(0),
+     fYPara(0),
+     fParam(param),
+     fdNdy0(0.),
+     fYWgt(0.),
+     fPtWgt(0.),
+     fBias(0.),
+     fTrials(0),
+     fDeltaPt(0.01),
+     fDecayer(0)
 {
 // Constructor
 // Gines Martinez 1/10/99 
-    fPtParaFunc = PtPara; 
-    fYParaFunc  = YPara;  
-    fIpParaFunc = IpPara;
-//  
-    fPtPara = 0;
-    fYPara  = 0;
-    fParam  = param;
-    fAnalog = analog;
+    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();
@@ -155,13 +164,6 @@ AliGenParam::AliGenParam(Int_t npart, Param_t param,
     SetChildPtRange();
     SetChildPhiRange();
     SetChildThetaRange();  
-    SetDeltaPt();
-}
-
-
-AliGenParam::AliGenParam(const AliGenParam & Paramd)
-{
-// copy constructor
 }
 
 //____________________________________________________________
@@ -176,24 +178,34 @@ AliGenParam::~AliGenParam()
 void AliGenParam::Init()
 {
 // Initialisation
-    SetMC(new AliPythia());
-    fPythia= (AliPythia*) fgMCEvGen;
-    
+
+    if (gMC) fDecayer = gMC->GetDecayer();
   //Begin_Html
   /*
     <img src="picts/AliGenParam.gif">
   */
   //End_Html
-    fPtPara = new TF1("Pt-Parametrization",fPtParaFunc,fPtMin,fPtMax,0);
+    char name[256];
+    sprintf(name, "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);
+    Int_t npx= Int_t((fPtMax - fPtMin) / fDeltaPt);
     
     fPtPara->SetNpx(npx);
+
+    sprintf(name, "y-parameterisation  for %s", GetName());
+    if (fYPara) fYPara->Delete();
+    fYPara  = new TF1(name, fYParaFunc, fYMin, fYMax, 0);
+    gROOT->GetListOfFunctions()->Remove(fYPara);
+
     
-    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);
+    sprintf(name, "pt-for-%s", GetName());
+    TF1 ptPara(name ,fPtParaFunc, 0, 15, 0);
+    sprintf(name, "y-for-%s", GetName());
+    TF1 yPara(name, fYParaFunc, -6, 6, 0);
 
 //
 // dN/dy| y=0
@@ -203,11 +215,11 @@ void AliGenParam::Init()
     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 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);
     Float_t phiWgt=(fPhiMax-fPhiMin)/2./TMath::Pi();
-    if (fAnalog == analog) {
+    if (fAnalog == kAnalog) {
        fYWgt  = intYS/fdNdy0;
        fPtWgt = intPtS/intPt0;
        fParentWeight = fYWgt*fPtWgt*phiWgt/fNpart;
@@ -218,35 +230,11 @@ void AliGenParam::Init()
     }
 //
 // particle decay related initialization
-    fPythia->DefineParticles();
-// semimuonic decays of charm and beauty
-    fPythia->ForceDecay(fForceDecay);
+    fDecayer->SetForceDecay(fForceDecay);
+    fDecayer->Init();
+
 //
-    switch (fForceDecay) 
-    {
-    case semielectronic:
-    case dielectron:
-    case b_jpsi_dielectron:
-    case b_psip_dielectron:
-       fChildSelect[0]=11;     
-       break;
-    case semimuonic:
-    case dimuon:
-    case b_jpsi_dimuon:
-    case b_psip_dimuon:
-       fChildSelect[0]=13;
-       break;
-    case pitomu:
-       fChildSelect[0]=13;
-       break;
-    case katomu:
-       fChildSelect[0]=13;
-       break;
-    case nodecay:
-       break;
-    case all:
-       break;
-    }
+    AliGenMC::Init();
 }
 
 //____________________________________________________________
@@ -262,52 +250,61 @@ void AliGenParam::Generate()
 // 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 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);
+  if(!particles) particles = new TClonesArray("TParticle",1000);
+  
+  TDatabasePDG *pDataBase = TDatabasePDG::Instance();
   //
   Float_t random[6];
  
 // Calculating vertex position per event
   for (j=0;j<3;j++) origin0[j]=fOrigin[j];
   if(fVertexSmear==kPerEvent) {
-      gMC->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]));
-      }
+      Vertex();
+      for (j=0;j<3;j++) origin0[j]=fVertex[j];
   }
+  
   Int_t ipa=0;
+  
 // Generating fNpart particles
+  fNprimaries = 0;
+  
   while (ipa<fNpart) {
       while(1) {
 //
-// particle type
-         Int_t iPart = fIpParaFunc();
-         fChildWeight=(fPythia->GetBraPart(iPart))*fParentWeight;        
-         Float_t am=fPythia->GetPMAS(fPythia->Lucomp(iPart),1);
-         gMC->Rndm(random,2);
+// particle type 
+         Int_t iPart = fIpParaFunc(fRandom);
+         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()));
+         ty = TMath::TanH(fYPara->GetRandom());
 //
 // pT
-         if (fAnalog == analog) {
+         if (fAnalog == kAnalog) {
              pt=fPtPara->GetRandom();
              wgtp=fParentWeight;
              wgtch=fChildWeight;
@@ -318,18 +315,25 @@ void AliGenParam::Generate()
              wgtch=fChildWeight*fPtParaFunc(& ptd, &dummy);
          }
          xmt=sqrt(pt*pt+am*am);
-         pl=xmt*ty/sqrt(1.-ty*ty);
+         if (TMath::Abs(ty)==1.) {
+             ty=0.;
+             Fatal("AliGenParam", 
+                   "Division by 0: Please check you rapidity range !");
+         }
+         
+         pl=xmt*ty/sqrt((1.-ty)*(1.+ty));
          theta=TMath::ATan2(pt,pl);
 // Cut on theta
          if(theta<fThetaMin || theta>fThetaMax) continue;
          ptot=TMath::Sqrt(pt*pt+pl*pl);
 // 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) {
-             gMC->Rndm(random,6);
+             Rndm(random,6);
              for (j=0;j<3;j++) {
                  origin0[j]=
                      fOrigin[j]+fOsigma[j]*TMath::Cos(2*random[2*j]*TMath::Pi())*
@@ -344,129 +348,191 @@ void AliGenParam::Generate()
 // if fForceDecay == none Primary particle is tracked by GEANT 
 // (In the latest, make sure that GEANT actually does all the decays you want)   
 //
-         if (fForceDecay != nodecay) {
+         Bool_t decayed = kFALSE;
+         
+
+         if (fForceDecay != kNoDecay) {
 // Using lujet to decay particle
              Float_t energy=TMath::Sqrt(ptot*ptot+am*am);
-             fPythia->DecayParticle(iPart,energy,theta,phi);
+             TLorentzVector pmom(p[0], p[1], p[2], energy);
+             fDecayer->Decay(iPart,&pmom);
 //
 // select decay particles
-             Int_t np=fPythia->ImportParticles(particles,"All");
+             Int_t np=fDecayer->ImportParticles(particles);
+
+             //  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();
+             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 =  (TParticle *) particles->At(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)))
-                 {
-                     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++;
+                     
+                     if ((ChildSelected(TMath::Abs(kf)) || fForceDecay == kAll) && 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 {
+                                 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,"Primary",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,"Decay",nt,wgtch);
-                     gAlice->KeepTrack(nt); 
-                 }
+// Parent
+                 
+                 
+                 PushTrack(0, -1, iPart, p, origin0, polar, 0, kPPrimary, nt, wgtp, ((decayed)? 11 : 1));
+                 pParent[0] = nt;
+                 KeepTrack(nt); 
+                 fNprimaries++;
+                 
+//
+// 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()/10;
+                         och[1] = origin0[1]+iparticle->Vy()/10;
+                         och[2] = origin0[2]+iparticle->Vz()/10;
+                         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,
+                                          0, 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,"Primary",nt,wgtp);
+           gAlice->GetMCApp()->
+               PushTrack(fTrackIt,-1,iPart,p,origin0,polar,0,kPPrimary,nt,wgtp, 1);
             ipa++; 
+           fNprimaries++;
          }
          break;
     } // while
   } // event loop
-}
+  
+  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->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);
-    
+// Normalisation for selected kinematic region
 //
-// 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;
+  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.;
+  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");     
 }
 
 
 
+