newly implemented model for slow nucleon production
[u/mrichter/AliRoot.git] / EVGEN / AliGenParam.cxx
index 32191ad..717dae0 100644 (file)
 // Decays are performed using Pythia.
 // andreas.morsch@cern.ch
 
-#include "AliGenParam.h"
-#include "AliDecayer.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 <TCanvas.h>
-#include <TH1.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)
 {
-// Deafault constructor
-    fPtPara = 0;
-    fYPara  = 0;
-    fParam  = 0;
-    fAnalog = kAnalog;
-    SetDeltaPt();
-    fDecayer = 0;
-
-
+  // Default constructor
 }
-
-AliGenParam::AliGenParam(Int_t npart, AliGenLib * Library,  Int_t param, char* tname):AliGenMC(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)
 {
-// Constructor using number of particles parameterisation id and library
+  // Constructor using number of particles parameterisation id and library
     fName = "Param";
     fTitle= "Particle Generator using pT and y parameterisation";
-    
-    fPtParaFunc = Library->GetPt(param, tname);
-    fYParaFunc  = Library->GetY (param, tname);
-    fIpParaFunc = Library->GetIp(param, tname);
-    
-    fPtPara = 0;
-    fYPara  = 0;
-    fParam  = param;
     fAnalog = kAnalog;
     SetForceDecay();
-    SetDeltaPt(); 
 }
-
 //____________________________________________________________
-
-AliGenParam::AliGenParam(Int_t npart, Int_t param, char* tname):AliGenMC(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)
 {
-// Constructor using parameterisation id and number of particles
-//
-    fName = "Param";
+  // 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;
@@ -104,27 +140,39 @@ AliGenParam::AliGenParam(Int_t npart, Int_t param, char* tname):AliGenMC(npart)
     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 *))                 
-    :AliGenMC(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)
 {
-// Constructor
-// Gines Martinez 1/10/99 
+  // Constructor
+  // Gines Martinez 1/10/99 
     fName = "Param";
     fTitle= "Particle Generator using pT and y parameterisation";
 
-    fPtParaFunc = PtPara; 
-    fYParaFunc  = YPara;  
-    fIpParaFunc = IpPara;
-//  
-    fPtPara = 0;
-    fYPara  = 0;
-    fParam  = param;
     fAnalog = kAnalog;
     fChildSelect.Set(5);
     for (Int_t i=0; i<5; i++) fChildSelect[i]=0;
@@ -134,29 +182,22 @@ AliGenParam::AliGenParam(Int_t npart, Int_t param,
     SetChildPtRange();
     SetChildPhiRange();
     SetChildThetaRange();  
-    SetDeltaPt();
-}
-
-
-AliGenParam::AliGenParam(const AliGenParam & Param)
-    :AliGenMC(Param)
-{
-// Copy constructor
-    Param.Copy(*this);
 }
 
 //____________________________________________________________
 AliGenParam::~AliGenParam()
 {
-// Destructor
+  // Destructor
     delete  fPtPara;
     delete  fYPara;
+  delete  fV2Para;
+  delete  fdNdPhi;
 }
 
 //____________________________________________________________
 void AliGenParam::Init()
 {
-// Initialisation
+  // Initialisation
 
     if (gMC) fDecayer = gMC->GetDecayer();
   //Begin_Html
@@ -164,29 +205,53 @@ void AliGenParam::Init()
     <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
+    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();    //TR: should probably be done differently in case of anisotropic phi...
     if (fAnalog == kAnalog) {
        fYWgt  = intYS/fdNdy0;
        fPtWgt = intPtS/intPt0;
@@ -196,34 +261,45 @@ 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();
 
-//
+  //
     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], 
@@ -240,34 +316,36 @@ void AliGenParam::Generate()
   //
   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) {
       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);
          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
+      //
+      // y
          ty = TMath::TanH(fYPara->GetRandom());
-//
-// pT
+      //
+      // pT
          if (fAnalog == kAnalog) {
              pt=fPtPara->GetRandom();
              wgtp=fParentWeight;
@@ -284,15 +362,25 @@ void AliGenParam::Generate()
              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*ty);
+         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;
@@ -303,23 +391,29 @@ 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);
 
              //  Selecting  GeometryAcceptance for particles fPdgCodeParticleforAcceptanceCut;
@@ -338,14 +432,15 @@ void AliGenParam::Generate()
              }
              
              if (np >1) {
-                 TParticle* iparticle =  (TParticle *) particles->At(0);
+                 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
+           // flagged particle
 
                      if (pFlag[i] == 1) {
                          ipF = iparticle->GetFirstDaughter();
@@ -354,14 +449,14 @@ void AliGenParam::Generate()
                          continue;
                      }
 
-// flag decay products of particles with long life-time (c tau > .3 mum)                     
+           // flag decay products of particles with long life-time (c tau > .3 mum)                  
                      
                      if (ks != 1) { 
-//                       TParticlePDG *particle = pDataBase->GetParticle(kf);
+             //                          TParticlePDG *particle = pDataBase->GetParticle(kf);
                          
                          Double_t lifeTime = fDecayer->GetLifetime(kf);
-//                       Double_t mass     = particle->Mass();
-//                       Double_t width    = particle->Width();
+             //                          Double_t mass     = particle->Mass();
+             //                          Double_t width    = particle->Width();
                          if (lifeTime > (Double_t) fMaxLifeTime) {
                              ipF = iparticle->GetFirstDaughter();
                              ipL = iparticle->GetLastDaughter();       
@@ -371,10 +466,10 @@ void AliGenParam::Generate()
                              pSelected[i]   = 1;
                          }
                      } // ks==1 ?
-//
-// children
+           //
+           // children
                      
-                     if (ChildSelected(TMath::Abs(kf)) || fForceDecay == kAll && trackIt[i])
+                     if ((ChildSelected(TMath::Abs(kf)) || fForceDecay == kAll || fSelectAll) && trackIt[i])
                      {
                          if (fCutOnChild) {
                              pc[0]=iparticle->Px();
@@ -399,38 +494,44 @@ void AliGenParam::Generate()
              Int_t iparent;
              if ((fCutOnChild && ncsel >0) || !fCutOnChild){
                  ipa++;
-//
-// Parent
-                 PushTrack(0, -1, iPart, p, origin0, polar, 0, kPPrimary, nt, wgtp);
+         //
+         // Parent
+                 
+                 
+                 PushTrack(0, -1, iPart, p, origin0, polar, time0, kPPrimary, nt, wgtp, ((decayed)? 11 : 1));
                  pParent[0] = nt;
                  KeepTrack(nt); 
-//
-// Decay Products
-//               
+                 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 ipa = iparticle->GetFirstMother()-1;
+                         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;
+                         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 (ipa > -1) {
-                             iparent = pParent[ipa];
+                         if (jpa > -1) {
+                             iparent = pParent[jpa];
                          } else {
                              iparent = -1;
                          }
                         
-                         PushTrack(fTrackIt*trackIt[i], iparent, kf,
+                         PushTrack(fTrackIt * trackIt[i], iparent, kf,
                                           pc, och, polar,
-                                          0, kPDecay, nt, wgtch);
+                                          time0 + iparticle->T(), kPDecay, nt, wgtch, ksc);
                          pParent[i] = nt;
                          KeepTrack(nt); 
+                         fNprimaries++;
                      } // Selected
                  } // Particle loop 
              }  // Decays by Lujet
@@ -442,17 +543,39 @@ void AliGenParam::Generate()
          } // kinematic selection
          else  // nodecay option, so parent will be tracked by GEANT (pions, kaons, eta, omegas, baryons)
          {
-           gAlice->
-               PushTrack(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
+  
   SetHighWaterMark(nt);
+
+  AliGenEventHeader* header = new AliGenEventHeader("PARAM");
+  header->SetPrimaryVertex(fVertex);
+  header->SetInteractionTime(fTime);
+  header->SetNProduced(fNprimaries);
+  AddHeader(header);
+}
+//____________________________________________________________________________________
+Float_t AliGenParam::GetRelativeArea(Float_t ptMin, Float_t ptMax, Float_t yMin, Float_t yMax, Float_t phiMin, Float_t phiMax)
+{
+  //
+  // Normalisation for selected kinematic region
+  //
+  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);
 }
 
-void AliGenParam::Draw()
+//____________________________________________________________________________________
+
+void AliGenParam::Draw( const char * /*opt*/)
 {
     //
     // Draw the pT and y Distributions
@@ -467,12 +590,6 @@ void AliGenParam::Draw()
      fYPara->GetHistogram()->SetXTitle("y");     
 }
 
-AliGenParam& AliGenParam::operator=(const  AliGenParam& rhs)
-{
-// Assignment operator
-    rhs.Copy(*this);
-    return *this;
-}