]> git.uio.no Git - u/mrichter/AliRoot.git/blobdiff - ITS/AliITStrackerV2.cxx
Example macro for the creation of tags (P.Christakoglou)
[u/mrichter/AliRoot.git] / ITS / AliITStrackerV2.cxx
index 6d6a5335cf1856de8d1b889b1874ad61e5b354ee..44375b53cebf6210327cb5fd76b82764065a9b1c 100644 (file)
@@ -43,8 +43,7 @@ AliITStrackerV2::AliITStrackerV2(const AliITSgeom *geom) : AliTracker() {
   //--------------------------------------------------------------------
   AliITSgeom *g=(AliITSgeom*)geom;
 
-  Float_t x,y,z;
-  Int_t i;
+  Float_t x,y,z;  Int_t i;
   for (i=1; i<kMaxLayer+1; i++) {
     Int_t nlad=g->GetNladders(i);
     Int_t ndet=g->GetNdetectors(i);
@@ -72,6 +71,10 @@ AliITStrackerV2::AliITStrackerV2(const AliITSgeom *geom) : AliTracker() {
         Double_t phi=TMath::ATan2(rot[1],rot[0])+TMath::Pi();
         phi+=TMath::Pi()/2;
         if (i==1) phi+=TMath::Pi();
+
+        if (phi<0) phi+=TMath::TwoPi();
+        else if (phi>=TMath::TwoPi()) phi-=TMath::TwoPi();
+
         Double_t cp=TMath::Cos(phi), sp=TMath::Sin(phi);
         Double_t r=x*cp+y*sp;
 
@@ -116,35 +119,28 @@ Int_t AliITStrackerV2::LoadClusters(TTree *cTree) {
   branch->SetAddress(&clusters);
 
   Int_t j=0;
-  Int_t detector=0;
   for (Int_t i=0; i<kMaxLayer; i++) {
     Int_t ndet=fgLayers[i].GetNdetectors();
     Int_t jmax = j + fgLayers[i].GetNladders()*ndet;
+
+    Double_t r=fgLayers[i].GetR();
+    Double_t circ=TMath::TwoPi()*r;
+
     for (; j<jmax; j++) {           
       if (!cTree->GetEvent(j)) continue;
       Int_t ncl=clusters->GetEntriesFast();
       while (ncl--) {
         AliITSclusterV2 *c=(AliITSclusterV2*)clusters->UncheckedAt(ncl);
-       detector = c->GetDetectorIndex();
+
+        Int_t idx=c->GetDetectorIndex();
+        Double_t y=r*fgLayers[i].GetDetector(idx).GetPhi()+c->GetY();
+        if (y>circ) y-=circ; else if (y<0) y+=circ;
+        c->SetPhiR(y);
+
         fgLayers[i].InsertCluster(new AliITSclusterV2(*c));
       }
       clusters->Delete();
-      //add dead zone virtual "cluster"
-      
-      if (i<1){
-       for (Float_t ydead = -2.; ydead < 2. ; ydead+=0.05){     
-         Int_t lab[4] = {0,0,0,detector};
-         Int_t info[3] = {0,0,0};
-         Float_t hit[5]={ydead,0,1,0.01,0};
-         fgLayers[i].InsertCluster(new AliITSclusterV2(lab, hit, info));
-         //
-         hit[1]=-7.;
-         fgLayers[i].InsertCluster(new AliITSclusterV2(lab, hit, info));
-       }       
-      }
-      
     }
-    //
     fgLayers[i].ResetRoad(); //road defined by the cluster density
   }
 
@@ -217,7 +213,7 @@ Int_t AliITStrackerV2::Clusters2Tracks(AliESD *event) {
         delete t;
         continue;
       }
-      if (TMath::Abs(t->GetD())>5) {
+      if (TMath::Abs(t->GetD())>4) {
        delete t;
        continue;
       }
@@ -228,114 +224,53 @@ Int_t AliITStrackerV2::Clusters2Tracks(AliESD *event) {
          delete t;
          continue;
       }
-      t->SetReconstructed(kFALSE);
       itsTracks.AddLast(t);
     }
   } /* End Read ESD tracks */
 
   itsTracks.Sort();
   Int_t nentr=itsTracks.GetEntriesFast();
-  fTrackHypothesys.Expand(nentr);
+
   Int_t ntrk=0;
   for (fPass=0; fPass<2; fPass++) {
      Int_t &constraint=fConstraint[fPass]; if (constraint<0) continue;
      for (Int_t i=0; i<nentr; i++) {
-       fCurrentEsdTrack = i;
        AliITStrackV2 *t=(AliITStrackV2*)itsTracks.UncheckedAt(i);
-       if (t==0) continue;              //this track has been already tracked
-       if (t->GetReconstructed()) continue;  //this track was  already  "succesfully" reconstructed
-       if ( (TMath::Abs(t->GetD(GetX(),GetY()))  >2.) && fConstraint[fPass]) continue;
-       if ( (TMath::Abs(t->GetZat(GetX())-GetZ())>2.) && fConstraint[fPass]) continue;
-
+       if (t==0) continue;           //this track has been already tracked
        Int_t tpcLabel=t->GetLabel(); //save the TPC track label
 
        ResetTrackToFollow(*t);
        ResetBestTrack();
 
        for (FollowProlongation(); fI<kMaxLayer; fI++) {
-        while (TakeNextProlongation()) {
-           FollowProlongation();
-        }
+          while (TakeNextProlongation()) FollowProlongation();
        }
 
-       SortTrackHypothesys(fCurrentEsdTrack,0.9);  //MI change
-       CompressTrackHypothesys(fCurrentEsdTrack,0.90,2);  //MI change
-
-       /*
        if (fBestTrack.GetNumberOfClusters() == 0) continue;
-       
+
        if (fConstraint[fPass]) {
-        ResetTrackToFollow(*t);
-        if (!RefitAt(3.7, &fTrackToFollow, &fBestTrack)) continue;
-        ResetBestTrack();
-        }
-       
+          ResetTrackToFollow(*t);
+          if (!RefitAt(3.7, &fTrackToFollow, &fBestTrack)) continue;
+          ResetBestTrack();
+       }
+
        fBestTrack.SetLabel(tpcLabel);
        fBestTrack.CookdEdx();
        CookLabel(&fBestTrack,0.); //For comparison only
        fBestTrack.UpdateESDtrack(AliESDtrack::kITSin);
-       //UseClusters(&fBestTrack);
+       UseClusters(&fBestTrack);
        delete itsTracks.RemoveAt(i);
        ntrk++;
-       */
-       AliITStrackV2 * besttrack = GetBestHypothesys(fCurrentEsdTrack,t,5);
-       if (!besttrack) continue;
-       besttrack->SetLabel(tpcLabel);
-       besttrack->CookdEdx();
-       besttrack->SetFakeRatio(1.);
-       CookLabel(besttrack,0.); //For comparison only
-       //       besttrack->UpdateESDtrack(AliESDtrack::kITSin);
-       
-       if (besttrack->GetChi2()/besttrack->GetNumberOfClusters()>3.5){
-        if ( (TMath::Abs(besttrack->GetD(GetX(),GetY()))>0.4) && fConstraint[fPass]) {
-          CompressTrackHypothesys(fCurrentEsdTrack,0.0,0);
-          continue;
-        }
-        if ( (TMath::Abs(besttrack->GetZat(GetX()) -GetZ() )>0.4) && fConstraint[fPass]){
-          CompressTrackHypothesys(fCurrentEsdTrack,0.0,0);
-          continue;
-        }
-       }
-       
-       //delete itsTracks.RemoveAt(i);
-       t->SetReconstructed();
-       ntrk++;              
-       
      }
   }
-  
-  for (Int_t i=0; i<nentr; i++) {
-    fCurrentEsdTrack = i;
-    AliITStrackV2 *t=(AliITStrackV2*)itsTracks.UncheckedAt(i);
-    if (t==0) continue;         
-    Int_t tpcLabel=t->GetLabel(); //save the TPC track label
-    AliITStrackV2 * besttrack = GetBestHypothesysMIP(fCurrentEsdTrack,t);
-    if (!besttrack) continue;
-
-    besttrack->SetLabel(tpcLabel);
-    besttrack->CookdEdx();
-    besttrack->SetFakeRatio(1.);
-    CookLabel(besttrack,0.); //For comparison only
-    besttrack->UpdateESDtrack(AliESDtrack::kITSin);
-  }
-  //
 
   itsTracks.Delete();
-  //
-  Int_t entries = fTrackHypothesys.GetEntriesFast();
-  for (Int_t ientry=0;ientry<entries;ientry++){
-    TObjArray * array =(TObjArray*)fTrackHypothesys.UncheckedAt(ientry);
-    if (array) array->Delete();
-    delete fTrackHypothesys.RemoveAt(ientry); 
-  }
 
-  fTrackHypothesys.Delete();
   Info("Clusters2Tracks","Number of prolonged tracks: %d\n",ntrk);
 
   return 0;
 }
 
-
 Int_t AliITStrackerV2::PropagateBack(AliESD *event) {
   //--------------------------------------------------------------------
   // This functions propagates reconstructed ITS tracks back
@@ -383,7 +318,7 @@ Int_t AliITStrackerV2::PropagateBack(AliESD *event) {
         //fTrackToFollow.CookdEdx();
         CookLabel(&fTrackToFollow,0.); //For comparison only
         fTrackToFollow.UpdateESDtrack(AliESDtrack::kITSout);
-        //UseClusters(&fTrackToFollow);
+        UseClusters(&fTrackToFollow);
         ntrk++;
      }
      delete t;
@@ -410,7 +345,7 @@ Int_t AliITStrackerV2::RefitInward(AliESD *event) {
     if ((esd->GetStatus()&AliESDtrack::kITSout) == 0) continue;
     if (esd->GetStatus()&AliESDtrack::kITSrefit) continue;
     if (esd->GetStatus()&AliESDtrack::kTPCout)
-      if ((esd->GetStatus()&AliESDtrack::kTPCrefit)==0) continue;
+    if ((esd->GetStatus()&AliESDtrack::kTPCrefit)==0) continue;
 
     AliITStrackV2 *t=0;
     try {
@@ -431,14 +366,11 @@ Int_t AliITStrackerV2::RefitInward(AliESD *event) {
     ResetTrackToFollow(*t);
     fTrackToFollow.ResetClusters();
 
-    if ((esd->GetStatus()&AliESDtrack::kTPCin)==0)
-      fTrackToFollow.ResetCovariance();
-
     //Refitting...
     if (RefitAt(3.7, &fTrackToFollow, t)) {
        fTrackToFollow.SetLabel(t->GetLabel());
        fTrackToFollow.CookdEdx();
-       CookLabel(&fTrackToFollow,0.0); //For comparison only
+       CookLabel(&fTrackToFollow,0.); //For comparison only
 
        if (fTrackToFollow.PropagateTo(3.,0.0028,65.19)) {//The beam pipe    
          Double_t a=fTrackToFollow.GetAlpha();
@@ -457,7 +389,10 @@ Int_t AliITStrackerV2::RefitInward(AliESD *event) {
 
         if (fTrackToFollow.Propagate(fv+a,xv)) {
             fTrackToFollow.UpdateESDtrack(AliESDtrack::kITSrefit);
-            //UseClusters(&fTrackToFollow);
+            Float_t d=fTrackToFollow.GetD(GetX(),GetY());
+            Float_t z=fTrackToFollow.GetZ()-GetZ();
+            fTrackToFollow.GetESDtrack()->SetImpactParameters(d,z);
+            UseClusters(&fTrackToFollow);
             {
             AliITSclusterV2 c; c.SetY(yv); c.SetZ(GetZ());
             c.SetSigmaY2(GetSigmaY()*GetSigmaY());
@@ -551,70 +486,42 @@ void AliITStrackerV2::FollowProlongation() {
       return;
     }
 
-    //    if (TMath::Abs(fTrackToFollow.GetZ()-GetZ()) > r+dz) return;
+    if (TMath::Abs(fTrackToFollow.GetZ()-GetZ()) > r+dz) return;
 
     //Double_t dy=4*TMath::Sqrt(track.GetSigmaY2() + kSigmaY2[i]);
-    if (TMath::Abs(track.GetSnp()>kMaxSnp)) {
-      fI--;
-      continue;   // MI
-    }
     if (dy < 0.5*TMath::Abs(track.GetSnp())) dy=0.5*TMath::Abs(track.GetSnp());
     if (dy > kMaxRoad) {
       //Warning("FollowProlongation","too broad road in Y !\n");
       return;
     }
 
+    fI--;
+
     Double_t zmin=track.GetZ() - dz; 
     Double_t zmax=track.GetZ() + dz;
     Double_t ymin=track.GetY() + r*phi - dy;
     Double_t ymax=track.GetY() + r*phi + dy;
-    layer.SelectClusters(zmin,zmax,ymin,ymax); 
-    fI--;
+    if (layer.SelectClusters(zmin,zmax,ymin,ymax)==0) 
+       if (fLayersNotToSkip[fI]) return;  
+
+    if (!TakeNextProlongation()) 
+       if (fLayersNotToSkip[fI]) return;
 
-    //take another prolongation
-    if (!TakeNextProlongation()){ 
-      //skipped++;
-      fTrackToFollow.IncrementNSkipped();
-      if (fLayersNotToSkip[fI]||fTrackToFollow.GetNSkipped()>1) return;
-    }
-    if (fTrackToFollow.GetNUsed()>1) return;
-    if (fTrackToFollow.GetNUsed()+fTrackToFollow.GetNSkipped()>1) return;    
-    if ( (fI<3) && ( fTrackToFollow.GetChi2()/fTrackToFollow.GetNumberOfClusters()>kChi2PerCluster)) return;
   } 
 
   //deal with the best track
   Int_t ncl=fTrackToFollow.GetNumberOfClusters();
   Int_t nclb=fBestTrack.GetNumberOfClusters();
-  if (ncl){
-    if (ncl<4) return;
-    if ( (ncl<6) && (fTrackToFollow.GetChi2()/float(ncl))>3) return;
-    if (fTrackToFollow.GetChi2()/ncl>5.5) return;
-    fTrackToFollow.CookdEdx();
-    if (fTrackToFollow.GetESDtrack()->GetTPCsignal()>80.)
-      if ((fTrackToFollow.GetdEdx()/fTrackToFollow.GetESDtrack()->GetTPCsignal())<0.35){
-       // mismatch in dedx
-       return;
-      }
-    //
-    fTrackToFollow.SetLabel(fTrackToFollow.GetESDtrack()->GetLabel());
-    CookLabel(&fTrackToFollow,0.); //
-    //
-    if ( (nclb>3) && ((fTrackToFollow.GetChi2()/ncl)<(3*fBestTrack.GetChi2()/(nclb))))
-      AddTrackHypothesys(new AliITStrackV2(fTrackToFollow), fCurrentEsdTrack);
-    else 
-      if (ncl>3) AddTrackHypothesys(new AliITStrackV2(fTrackToFollow), fCurrentEsdTrack);
-    if (ncl >= nclb) {
-      Double_t chi2=fTrackToFollow.GetChi2();
-      if (chi2/ncl < kChi2PerCluster) {        
-        if (ncl > nclb ) {
-         ResetBestTrack();
+  if (ncl)
+  if (ncl >= nclb) {
+     Double_t chi2=fTrackToFollow.GetChi2();
+     if (chi2/ncl < kChi2PerCluster) {        
+        if (ncl > nclb || chi2 < fBestTrack.GetChi2()) {
+           ResetBestTrack();
         }
-       if ( (ncl == nclb) && chi2 < fBestTrack.GetChi2()) {
-         ResetBestTrack();
-        }      
-      }
-    }
+     }
   }
+
 }
 
 Int_t AliITStrackerV2::TakeNextProlongation() {
@@ -635,9 +542,11 @@ Int_t AliITStrackerV2::TakeNextProlongation() {
   } 
 
   const AliITSclusterV2 *c=0; Int_t ci=-1;
-  Double_t chi2=12345.;
+  const AliITSclusterV2 *cc=0; Int_t cci=-1;
+  Double_t chi2=kMaxChi2;
   while ((c=layer.GetNextCluster(ci))!=0) {
     Int_t idet=c->GetDetectorIndex();
+
     if (fTrackToFollow.GetDetectorIndex()!=idet) {
        const AliITSdetector &det=layer.GetDetector(idet);
        ResetTrackToFollow(fTracks[fI]);
@@ -652,33 +561,25 @@ Int_t AliITStrackerV2::TakeNextProlongation() {
     if (TMath::Abs(fTrackToFollow.GetZ() - c->GetZ()) > dz) continue;
     if (TMath::Abs(fTrackToFollow.GetY() - c->GetY()) > dy) continue;
 
-    chi2=fTrackToFollow.GetPredictedChi2(c); if (chi2<kMaxChi2) break;
+    Double_t ch2=fTrackToFollow.GetPredictedChi2(c); 
+    if (ch2 > chi2) continue;
+    chi2=ch2;
+    cc=c; cci=ci;
+    break;
   }
 
-  if (chi2>=kMaxChi2) return 0;
-  if (!c) return 0;
-  if (c->IsUsed()&&c->GetNy()<5) {  //shared factor    
-    chi2+=1;
-    chi2*=2*(1./(TMath::Max(c->GetNy(),1)));
-  }
-  if (c->GetQ()==0){  //dead zone virtual cluster
-    chi2*=4.;
-    chi2+=20;
-    fTrackToFollow.IncrementNUsed();
-    return 1;
-  }
-  //if ((fI<2)&&chi2>kMaxChi2In) return 0;
+  if (!cc) return 0;
 
-  if (!fTrackToFollow.Update(c,chi2,(fI<<28)+ci)) {
+  if (!fTrackToFollow.Update(cc,chi2,(fI<<28)+cci)) {
      //Warning("TakeNextProlongation","filtering failed !\n");
      return 0;
   }
-  if (c->IsUsed()&&c->GetNy()<5) fTrackToFollow.IncrementNUsed();
+
   if (fTrackToFollow.GetNumberOfClusters()>1)
   if (TMath::Abs(fTrackToFollow.GetD())>4) return 0;
 
   fTrackToFollow.
-    SetSampledEdx(c->GetQ(),fTrackToFollow.GetNumberOfClusters()-1); //b.b.
+    SetSampledEdx(cc->GetQ(),fTrackToFollow.GetNumberOfClusters()-1); //b.b.
 
   {
   Double_t x0;
@@ -690,15 +591,6 @@ Int_t AliITStrackerV2::TakeNextProlongation() {
     Double_t d=GetEffectiveThickness(0,0); //Think of this !!!!
     Double_t xyz[]={GetX(),GetY(),GetZ()};
     Double_t ers[]={GetSigmaX(),GetSigmaY(),GetSigmaZ()};
-    Double_t deltad = TMath::Abs(fTrackToFollow.GetD(GetX(),GetY()));
-    Double_t deltaz = TMath::Abs(fTrackToFollow.GetZat(GetX())-GetZ());
-
-    if ( (fI==4) &&  (deltad>2.0 || deltaz>1.5))  return 0; // don't "improve" secondaries     
-    if ( (fI==3) &&  (deltad>1.5 || deltaz>0.9))  return 0; // don't "improve" secondaries 
-    if ( (fI==2) &&  (deltad>0.9 || deltaz>0.6))  return 1; // don't "improve" secondaries 
-    if ( (fI==1) &&  (deltad>0.3 || deltaz>0.3))  return 1; // don't "improve" secondaries 
-    if ( (fI==0) &&  (deltad>0.1 || deltaz>0.1))  return 1; // don't "improve" secondaries 
-
     fTrackToFollow.Improve(d,xyz,ers);
   }
 
@@ -710,8 +602,14 @@ AliITStrackerV2::AliITSlayer::AliITSlayer() {
   //--------------------------------------------------------------------
   //default AliITSlayer constructor
   //--------------------------------------------------------------------
-  fN=0;
+  fR=0.; fPhiOffset=0.; fZOffset=0.;
+  fNladders=0; fNdetectors=0;
   fDetectors=0;
+  
+  for (Int_t i=0; i<kNsector; i++) fN[i]=0;
+  fNsel=0;
+
+  fRoad=2*fR*TMath::Sqrt(3.14/1.);//assuming that there's only one cluster
 }
 
 AliITStrackerV2::AliITSlayer::
@@ -723,8 +621,10 @@ AliITSlayer(Double_t r,Double_t p,Double_t z,Int_t nl,Int_t nd) {
   fNladders=nl; fNdetectors=nd;
   fDetectors=new AliITSdetector[fNladders*fNdetectors];
 
-  fN=0;
-  fI=0;
+  for (Int_t i=0; i<kNsector; i++) fN[i]=0;
+  fNsel=0;
+
+  for (Int_t i=0; i<kMaxClusterPerLayer; i++) fClusters[i]=0;
 
   fRoad=2*fR*TMath::Sqrt(3.14/1.);//assuming that there's only one cluster
 }
@@ -734,25 +634,20 @@ AliITStrackerV2::AliITSlayer::~AliITSlayer() {
   // AliITSlayer destructor
   //--------------------------------------------------------------------
   delete[] fDetectors;
-  for (Int_t i=0; i<fN; i++) delete fClusters[i];
-  for (Int_t i=0; i<kMaxClusterPerLayer;i++) fClusterWeight[i]=0;
+  ResetClusters();
 }
 
 void AliITStrackerV2::AliITSlayer::ResetClusters() {
   //--------------------------------------------------------------------
   // This function removes loaded clusters
   //--------------------------------------------------------------------
-  for (Int_t i=0; i<fN; i++) delete fClusters[i];
-  for (Int_t i=0; i<kMaxClusterPerLayer;i++) fClusterWeight[i]=0;
-  fN=0;
-  fI=0;
-}
-
-void AliITStrackerV2::AliITSlayer::ResetWeights() {
-  //--------------------------------------------------------------------
-  // This function reset weights of the clusters
-  //--------------------------------------------------------------------
-  for (Int_t i=0; i<kMaxClusterPerLayer;i++) fClusterWeight[i]=0;
+   for (Int_t s=0; s<kNsector; s++) {
+       Int_t &n=fN[s];
+       while (n) {
+          n--;
+          delete fClusters[s*kMaxClusterPerSector+n];
+       }
+   }
 }
 
 void AliITStrackerV2::AliITSlayer::ResetRoad() {
@@ -760,37 +655,57 @@ void AliITStrackerV2::AliITSlayer::ResetRoad() {
   // This function calculates the road defined by the cluster density
   //--------------------------------------------------------------------
   Int_t n=0;
-  for (Int_t i=0; i<fN; i++) {
-     if (TMath::Abs(fClusters[i]->GetZ())<fR) n++;
+  for (Int_t s=0; s<kNsector; s++) {
+    Int_t i=fN[s];
+    while (i--) 
+       if (TMath::Abs(fClusters[s*kMaxClusterPerSector+i]->GetZ())<fR) n++;
   }
   if (n>1) fRoad=2*fR*TMath::Sqrt(3.14/n);
 }
 
 Int_t AliITStrackerV2::AliITSlayer::InsertCluster(AliITSclusterV2 *c) {
   //--------------------------------------------------------------------
-  //This function adds a cluster to this layer
+  // This function inserts a cluster to this layer in increasing
+  // order of the cluster's fZ
   //--------------------------------------------------------------------
-  if (fN==kMaxClusterPerLayer) {
-    ::Error("InsertCluster","Too many clusters !\n");
-    return 1;
+  Float_t circ=TMath::TwoPi()*fR;
+  Int_t sec=Int_t(kNsector*c->GetPhiR()/circ);
+  if (sec>=kNsector) {
+     ::Error("InsertCluster","Wrong sector !\n");
+     return 1;
   }
-
-  if (fN==0) {fClusters[fN++]=c; return 0;}
-  Int_t i=FindClusterIndex(c->GetZ());
-  memmove(fClusters+i+1 ,fClusters+i,(fN-i)*sizeof(AliITSclusterV2*));
-  fClusters[i]=c; fN++;
-
+  Int_t &n=fN[sec];
+  if (n>=kMaxClusterPerSector) {
+     ::Error("InsertCluster","Too many clusters !\n");
+     return 1;
+  }
+  if (n==0) fClusters[sec*kMaxClusterPerSector]=c;
+  else {
+     Int_t i=FindClusterIndex(c->GetZ(),sec);
+     Int_t k=n-i+sec*kMaxClusterPerSector;
+     memmove(fClusters+i+1 ,fClusters+i,k*sizeof(AliITSclusterV2*));
+     fClusters[i]=c;
+  }
+  n++;
   return 0;
 }
 
-Int_t AliITStrackerV2::AliITSlayer::FindClusterIndex(Double_t z) const {
+Int_t 
+AliITStrackerV2::AliITSlayer::FindClusterIndex(Float_t z,Int_t s) const {
   //--------------------------------------------------------------------
-  // This function returns the index of the nearest cluster 
+  // For the sector "s", this function returns the index of the first 
+  // with its fZ >= "z". 
   //--------------------------------------------------------------------
-  if (fN==0) return 0;
-  if (z <= fClusters[0]->GetZ()) return 0;
-  if (z > fClusters[fN-1]->GetZ()) return fN;
-  Int_t b=0, e=fN-1, m=(b+e)/2;
+  Int_t nc=fN[s];
+  if (nc==0) return kMaxClusterPerSector*s;
+
+  Int_t b=kMaxClusterPerSector*s;
+  if (z <= fClusters[b]->GetZ()) return b;
+
+  Int_t e=b+nc-1;
+  if (z > fClusters[e]->GetZ()) return e+1;
+
+  Int_t m=(b+e)/2;
   for (; b<e; m=(b+e)/2) {
     if (z > fClusters[m]->GetZ()) b=m+1;
     else e=m; 
@@ -798,44 +713,71 @@ Int_t AliITStrackerV2::AliITSlayer::FindClusterIndex(Double_t z) const {
   return m;
 }
 
-void AliITStrackerV2::AliITSlayer::
-SelectClusters(Double_t zmin,Double_t zmax,Double_t ymin, Double_t ymax) {
+Int_t AliITStrackerV2::AliITSlayer::
+SelectClusters(Float_t zmin,Float_t zmax,Float_t ymin, Float_t ymax) {
   //--------------------------------------------------------------------
-  // This function sets the "window"
+  // This function selects clusters within the "window"
   //--------------------------------------------------------------------
-  fI=FindClusterIndex(zmin); fZmax=zmax;
-  Double_t circle=2*TMath::Pi()*fR;
-  if (ymax>circle) { ymax-=circle; ymin-=circle; }
-  fYmin=ymin; fYmax=ymax;
+    Float_t circ=fR*TMath::TwoPi();
+
+    if (ymin>circ) ymin-=circ; else if (ymin<0) ymin+=circ;
+    if (ymax>circ) ymax-=circ; else if (ymax<0) ymax+=circ;
+
+    Int_t i1=Int_t(kNsector*ymin/circ); if (i1==kNsector) i1--;
+    if (fN[i1]!=0) {
+       Float_t ym = (ymax<ymin) ? ymax+circ : ymax;
+       Int_t i=FindClusterIndex(zmin,i1), imax=i1*kMaxClusterPerSector+fN[i1];
+       for (; i<imax; i++) {
+           AliITSclusterV2 *c=fClusters[i];
+           if (c->IsUsed()) continue;
+           if (c->GetZ()>zmax) break;
+           if (c->GetPhiR()<=ymin) continue;
+           if (c->GetPhiR()>ym) continue;
+           fIndex[fNsel++]=i;
+       }
+    }
+
+    Int_t i2=Int_t(kNsector*ymax/circ); if (i2==kNsector) i2--;
+    if (i2==i1) return fNsel;
+
+    if (fN[i2]!=0) {
+       Float_t ym = (ymin>ymax) ? ymin-circ : ymin;
+       Int_t i=FindClusterIndex(zmin,i2), imax=i2*kMaxClusterPerSector+fN[i2];
+       for (; i<imax; i++) {
+           AliITSclusterV2 *c=fClusters[i];
+           if (c->IsUsed()) continue;
+           if (c->GetZ()>zmax) break;
+           if (c->GetPhiR()<=ym) continue;
+           if (c->GetPhiR()>ymax) continue;
+           fIndex[fNsel++]=i;
+       }
+    }
+
+    return fNsel;
 }
 
 const AliITSclusterV2 *AliITStrackerV2::AliITSlayer::GetNextCluster(Int_t &ci){
   //--------------------------------------------------------------------
   // This function returns clusters within the "window" 
   //--------------------------------------------------------------------
-  const AliITSclusterV2 *cluster=0;
-  for (Int_t i=fI; i<fN; i++) {
-    const AliITSclusterV2 *c=fClusters[i];
-    if (c->GetZ() > fZmax) break;
-    //    if (c->IsUsed()) continue;
-    const AliITSdetector &det=GetDetector(c->GetDetectorIndex());    
-    Double_t y=fR*det.GetPhi() + c->GetY();
-
-    if (y>2.*fR*TMath::Pi()) y -= 2*fR*TMath::Pi();
-    if (y>1.*fR*TMath::Pi() && fYmax<y) y -= 2*fR*TMath::Pi();
-
-    if (y<fYmin) continue;
-    if (y>fYmax) continue;
-    cluster=c; ci=i;
-    fI=i+1;
-    break; 
+  AliITSclusterV2 *c=0;
+  ci=-1;
+  if (fNsel) {
+     fNsel--;
+     ci=fIndex[fNsel]; 
+     c=fClusters[ci];
   }
+  return c; 
+}
 
-  return cluster;
+Int_t AliITStrackerV2::AliITSlayer::GetNumberOfClusters() const {
+  Int_t n=0;
+  for (Int_t s=0; s<kNsector; s++) n+=fN[s];
+  return n; 
 }
 
-Int_t AliITStrackerV2::AliITSlayer::
-FindDetectorIndex(Double_t phi, Double_t z) const {
+Int_t 
+AliITStrackerV2::AliITSlayer::FindDetectorIndex(Double_t phi,Double_t z)const {
   //--------------------------------------------------------------------
   //This function finds the detector crossed by the track
   //--------------------------------------------------------------------
@@ -983,28 +925,6 @@ Double_t AliITStrackerV2::GetEffectiveThickness(Double_t y,Double_t z) const
   return d/(xn*xn);
 }
 
-Int_t AliITStrackerV2::AliITSlayer::InRoad() const {
-  //--------------------------------------------------------------------
-  // This function returns number of clusters within the "window" 
-  //--------------------------------------------------------------------
-  Int_t ncl=0;
-  for (Int_t i=fI; i<fN; i++) {
-    const AliITSclusterV2 *c=fClusters[i];
-    if (c->GetZ() > fZmax) break;
-    if (c->IsUsed()) continue;
-    const AliITSdetector &det=GetDetector(c->GetDetectorIndex());    
-    Double_t y=fR*det.GetPhi() + c->GetY();
-
-    if (y>2.*fR*TMath::Pi()) y -= 2*fR*TMath::Pi();
-    if (y>1.*fR*TMath::Pi() && fYmax<y) y -= 2*fR*TMath::Pi();
-
-    if (y<fYmin) continue;
-    if (y>fYmax) continue;
-    ncl++;
-  }
-  return ncl;
-}
-
 Bool_t 
 AliITStrackerV2::RefitAt(Double_t xx,AliITStrackV2 *t,const AliITStrackV2 *c) {
   //--------------------------------------------------------------------
@@ -1138,18 +1058,6 @@ AliITStrackerV2::RefitAt(Double_t xx,AliITStrackV2 *t,const AliITStrackV2 *c) {
   return kTRUE;
 }
 
-
-Float_t  *AliITStrackerV2::GetWeight(Int_t index) {
-  //--------------------------------------------------------------------
-  //       Return pointer to a given cluster
-  //--------------------------------------------------------------------
-  Int_t l=(index & 0xf0000000) >> 28;
-  Int_t c=(index & 0x0fffffff) >> 00;
-  return fgLayers[l].GetWeight(c);
-}
-
-
-
 void AliITStrackerV2::UseClusters(const AliKalmanTrack *t, Int_t from) const {
   //--------------------------------------------------------------------
   // This function marks clusters assigned to the track
@@ -1157,547 +1065,8 @@ void AliITStrackerV2::UseClusters(const AliKalmanTrack *t, Int_t from) const {
   AliTracker::UseClusters(t,from);
 
   AliITSclusterV2 *c=(AliITSclusterV2 *)GetCluster(t->GetClusterIndex(0));
-  //if (c->GetQ()>2) c->Use();
-  if (c->GetSigmaZ2()>0.1) c->Use();
+  if (c && c->GetSigmaZ2()>0.1) c->UnUse();
   c=(AliITSclusterV2 *)GetCluster(t->GetClusterIndex(1));
-  //if (c->GetQ()>2) c->Use();
-  if (c->GetSigmaZ2()>0.1) c->Use();
-
-}
-
-
-void AliITStrackerV2::AddTrackHypothesys(AliITStrackV2 * track, Int_t esdindex)
-{
-  //------------------------------------------------------------------
-  // add track to the list of hypothesys
-  //------------------------------------------------------------------
-
-  if (esdindex>=fTrackHypothesys.GetEntriesFast()) fTrackHypothesys.Expand(esdindex*2+10);
-  //
-  TObjArray * array = (TObjArray*) fTrackHypothesys.At(esdindex);
-  if (!array) {
-    array = new TObjArray(10);
-    fTrackHypothesys.AddAt(array,esdindex);
-  }
-  array->AddLast(track);
-}
-
-void AliITStrackerV2::SortTrackHypothesys(Int_t esdindex, Float_t likelihoodlevel)
-{
-  //-------------------------------------------------------------------
-  // compress array of track hypothesys
-  // keep only maxsize best hypothesys
-  //-------------------------------------------------------------------
-  if (esdindex>fTrackHypothesys.GetEntriesFast()) return;
-  if (! (fTrackHypothesys.At(esdindex)) ) return;
-  TObjArray * array = (TObjArray*) fTrackHypothesys.At(esdindex);
-  Int_t entries = array->GetEntriesFast();
-
-  Float_t * chi2        = new Float_t[entries];
-  Float_t * probability = new Float_t[entries];
-  Float_t sumprobabilityall=0;
-  Int_t * index         = new Int_t[entries];
-  //
-  //
-  for (Int_t itrack=0;itrack<array->GetEntriesFast();itrack++){
-    AliITStrackV2 * track = (AliITStrackV2*)array->At(itrack);
-    //
-    if (track && track->GetNumberOfClusters()>(track->GetNUsed()+track->GetNSkipped())){
-      //
-      chi2[itrack] = track->GetChi2()/(track->GetNumberOfClusters()-track->GetNUsed()-track->GetNSkipped());      
-      if (track->GetESDtrack())
-       if (track->GetESDtrack()->GetTPCsignal()>80){
-         track->CookdEdx();
-         if ((track->GetdEdx()/track->GetESDtrack()->GetTPCsignal())<0.4){
-           Float_t factor = 2.+10.*(0.6-track->GetdEdx()/track->GetESDtrack()->GetTPCsignal());
-           chi2[itrack]*= factor;  //mismatch in dEdx
-         }
-       }      
-    }
-    else
-      chi2[itrack] = 10000000.;
-    probability[itrack] = 1./(0.3+chi2[itrack]);
-    sumprobabilityall+=probability[itrack];
-  }
-
-  TMath::Sort(entries,chi2,index,kFALSE);
-  TObjArray * newarray = new TObjArray();
-  Float_t     sumprobability = 0.;
-  for (Int_t i=0;i<entries;i++){
-    AliITStrackV2 * track = (AliITStrackV2*)array->At(index[i]);
-    if (!track) break;
-    if (chi2[index[i]]<30){
-      newarray->AddLast(array->RemoveAt(index[i])); 
-      track->SetChi2MIP(0,chi2[index[i]]);     // base chi 2    
-      sumprobability+= probability[index[i]]/sumprobabilityall;
-      if (sumprobability> likelihoodlevel) break;
-    }
-    else{
-      delete array->RemoveAt(index[i]);
-    }
-  }
-
-  array->Delete();
-  delete fTrackHypothesys.RemoveAt(esdindex);
-  fTrackHypothesys.AddAt(newarray,esdindex);
+  if (c && c->GetSigmaZ2()>0.1) c->UnUse();
 
-  delete [] chi2;
-  delete [] probability;
-  delete [] index;
-
-}
-
-
-void AliITStrackerV2::CompressTrackHypothesys(Int_t esdindex, Float_t likelihoodlevel, Int_t maxsize)
-{
-  //
-  //
-  if (esdindex>fTrackHypothesys.GetEntriesFast()) return;
-  if (! (fTrackHypothesys.At(esdindex)) ) return;
-  TObjArray * array = (TObjArray*) fTrackHypothesys.At(esdindex);
-  Int_t entries = array->GetEntriesFast();
-  //
-  if (likelihoodlevel>0.000001){
-    Float_t *probability = new Float_t[entries];
-    for (Int_t i=0;i<entries;i++) probability[i]=0.;
-    Float_t  sumprobabilityall=0;
-    Int_t   *index         = new Int_t[entries];
-    
-    for (Int_t itrack=0;itrack<entries;itrack++){
-      AliITStrackV2 * track = (AliITStrackV2*)array->At(itrack);
-      probability[itrack]=0;
-      if (!track) continue;
-      probability[itrack] = 1./(0.3+track->GetChi2MIP(0));
-      sumprobabilityall  += probability[itrack];
-      //    
-    }
-    if (sumprobabilityall<=0.000000000000001){
-      return;
-    }
-    for (Int_t itrack=0;itrack<entries;itrack++){
-      probability[itrack]/=sumprobabilityall;
-    }
-    
-    TMath::Sort(entries, probability, index, kTRUE);
-    //
-    TObjArray * newarray = new TObjArray();
-    Float_t     sumprobability = 0.;
-    for (Int_t i=0;i<entries;i++){
-      AliITStrackV2 * track = (AliITStrackV2*)array->At(index[i]);
-      if (!track) continue;    
-      newarray->AddLast(array->RemoveAt(index[i]));      
-      sumprobability+= probability[index[i]];
-      if (sumprobability> likelihoodlevel) break;
-      if (i>maxsize) break;
-    }
-    
-    array->Delete();
-    delete fTrackHypothesys.RemoveAt(esdindex);
-    fTrackHypothesys.AddAt(newarray,esdindex);
-    //    
-    delete []index;
-    delete []probability;
-  }
-  else{
-    array->Delete();
-    delete fTrackHypothesys.RemoveAt(esdindex);
-  }
 }
-
-
-AliITStrackV2 * AliITStrackerV2::GetBestHypothesys(Int_t esdindex, AliITStrackV2 * original, Int_t checkmax)
-{
-  //-------------------------------------------------------------
-  // try to find best hypothesy
-  // currently - minimal chi2 of track+backpropagated track+matching to the tpc track
-  //-------------------------------------------------------------
-  if (fTrackHypothesys.GetEntriesFast()<=esdindex) return 0;
-  TObjArray * array = (TObjArray*) fTrackHypothesys.At(esdindex);
-  if (!array) return 0;
-  Int_t entries = array->GetEntriesFast();
-  if (!entries) return 0;  
-  Float_t minchi2 = 100000;
-  Int_t   maxn    = 3;
-  AliITStrackV2 * besttrack=0;
-  Int_t accepted =0;
-  Int_t maxindex=0;
-  //
-  Float_t sumz2=0;
-  Float_t sumy2=0;
-  Float_t sumall=0;
-  for (Int_t itrack=0;itrack<entries; itrack++){
-    AliITStrackV2 * track = (AliITStrackV2*)array->At(itrack);
-    if (!track) continue;
-    sumall++;
-    sumz2+=track->GetSigmaZ2();
-    sumy2+=track->GetSigmaY2();
-  }
-  sumz2/=sumall;
-  sumy2/=sumall;
-
-  Float_t dedxmismatch=1;
-  for (Int_t i=0;i<entries;i++){    
-    maxindex = i;
-    AliITStrackV2 * track = (AliITStrackV2*)array->At(i);    
-    if (!track) continue;
-    track->SetChi2MIP(1,1000000);
-    track->SetChi2MIP(2,1000000);
-
-    if ( (track->GetNumberOfClusters()-track->GetNSkipped()-track->GetNUsed())<2) continue;
-    //
-    if (track->GetESDtrack())
-      if (track->GetESDtrack()->GetTPCsignal()>80){
-       track->CookdEdx();      
-       if ((track->GetdEdx()/track->GetESDtrack()->GetTPCsignal())<0.4){
-         //mismatch in dEdx 
-         dedxmismatch= 2.+ 10.*(0.6-track->GetdEdx()/track->GetESDtrack()->GetTPCsignal());
-       }
-      }
-
-    //    track->SetLabel(original->GetLabel());
-    //CookLabel(track,0.0);
-    //if (track->GetFakeRatio()>0.01) continue;
-    //
-    //
-    // backtrack
-    AliITStrackV2 * backtrack = new AliITStrackV2(*track);
-    backtrack->ResetCovariance();
-    backtrack->ResetClusters();
-    Double_t x = original->GetX();
-    if (!RefitAt(x,backtrack,track)){
-      delete backtrack;
-      delete array->RemoveAt(i);
-      continue;
-    }
-    if (  (backtrack->GetChi2() / float(backtrack->GetNumberOfClusters()-track->GetNSkipped()-track->GetNUsed()-0.5))>6) 
-      {
-       delete backtrack; 
-       delete array->RemoveAt(i);
-       continue;
-      }
-    Double_t deltac   = backtrack->GetC()-original->GetC();
-    Double_t deltatgl = backtrack->GetTgl()-original->GetTgl();
-    //
-    Double_t poolc2      = (deltac*deltac)/(original->GetCov44()+backtrack->GetCov44());
-    Double_t pooltgl2    = (deltatgl*deltatgl)/(original->GetCov33()+backtrack->GetCov33());
-    if ((poolc2+pooltgl2)>32){  //4 sigma
-      delete backtrack; 
-      delete array->RemoveAt(i);
-      continue;      
-    }
-    //Double_t bpoolc      = (deltac*deltac)/(original->GetCov44());
-    //Double_t bpooltgl    = (deltatgl*deltatgl)/(original->GetCov33());
-
-    //
-    //forward track - without constraint
-    AliITStrackV2 * forwardtrack = new AliITStrackV2(*original);
-    //    forwardtrack->ResetCovariance();
-    forwardtrack->ResetClusters();
-    x = track->GetX();
-    if (!RefitAt(x,forwardtrack,track)){
-      delete forwardtrack;
-      delete backtrack;
-      delete array->RemoveAt(i);
-      continue;
-    }
-    if ( (forwardtrack->GetChi2()/float(forwardtrack->GetNumberOfClusters()-track->GetNSkipped()-track->GetNUsed()))>6) {
-      delete forwardtrack; 
-      delete backtrack;
-      delete array->RemoveAt(i);
-      continue;
-    }
-    //
-    accepted++;
-    if (accepted>checkmax){
-      delete backtrack;
-      delete forwardtrack;
-      break;
-    }
-    Double_t chi2 = (backtrack->GetChi2()/(backtrack->GetNumberOfClusters()-1-track->GetNSkipped()-track->GetNUsed())+
-                    forwardtrack->GetChi2()/(forwardtrack->GetNumberOfClusters()-track->GetNSkipped()-track->GetNUsed()));
-      //                     bpoolc+bpooltgl;
-    //    chi2 *= (forwardtrack->GetSigmaZ2()/sumz2+forwardtrack->GetSigmaY2()/sumy2);
-    chi2 *= dedxmismatch;
-    //
-    //
-    track->SetChi2MIP(1,backtrack->GetChi2()/(backtrack->GetNumberOfClusters()-1-track->GetNSkipped()-track->GetNUsed()));
-    track->SetChi2MIP(2,forwardtrack->GetChi2()/(forwardtrack->GetNumberOfClusters()-track->GetNSkipped()-track->GetNUsed()));
-    track->SetChi2MIP(3,poolc2+pooltgl2);
-    //
-    
-    if (track->GetNumberOfClusters()>maxn){
-      delete besttrack;
-      besttrack =  new AliITStrackV2(*forwardtrack);
-      maxn      =  track->GetNumberOfClusters();
-      minchi2   =  chi2;
-      delete backtrack;
-      delete forwardtrack;
-      continue;
-    }   
-    //
-    if (chi2 < minchi2){
-      besttrack = new AliITStrackV2(*forwardtrack);
-      minchi2   = chi2;      
-    }    
-    delete backtrack;
-    delete forwardtrack;
-  }
-  //
-  //
-  if (!besttrack || besttrack->GetNumberOfClusters()<4) {
-    delete besttrack;
-    return 0;
-  }
-
-  //
-  besttrack->SetLabel(original->GetLabel());
-  CookLabel(besttrack,0.0);
-  //
-  // calculate "weight of the cluster"
-  //
-
-  {
-    //sign usage information for clusters
-    Int_t clusterindex[6][100];
-    Double_t clusterweight[6][100];
-    for (Int_t ilayer=0;ilayer<6;ilayer++)
-      for (Int_t icluster=0;icluster<100;icluster++){
-       clusterindex[ilayer][icluster]   = -1;
-       clusterweight[ilayer][icluster]  = 0;
-      }
-    //printf("%d\t%d\n",esdindex, entries);
-    //
-    Float_t sumchi2=0;
-    for (Int_t itrack=0;itrack<entries; itrack++){
-      AliITStrackV2 * track = (AliITStrackV2*)array->At(itrack);
-      if (!track) continue;
-      if (track->GetChi2MIP(1)>1000) continue;  //not accepted
-      sumchi2 +=1./(0.3+track->GetChi2MIP(1)+track->GetChi2MIP(2));
-    }
-    for (Int_t itrack=0;itrack<entries;itrack++){
-      AliITStrackV2 * track = (AliITStrackV2*)array->At(itrack);
-      if (!track) continue;
-      if (track->GetChi2MIP(1)>1000) continue;  //not accepted  
-      for (Int_t icluster=0;icluster<track->GetNumberOfClusters();icluster++){     
-       Int_t tindex = track->GetClusterIndex(icluster);
-       Int_t ilayer = (tindex & 0xf0000000) >> 28;
-       if (tindex<0) continue;
-       Int_t cindex =0;
-       //
-       for (cindex=0;cindex<100;cindex++){
-         if (clusterindex[ilayer][cindex]<0) break;
-         if (clusterindex[ilayer][cindex]==tindex) break;
-       }
-       if (cindex>100) break;
-       if (clusterindex[ilayer][cindex]!=tindex) clusterindex[ilayer][cindex] = tindex;
-       clusterweight[ilayer][cindex]+= (1./(0.3+track->GetChi2MIP(1)+track->GetChi2MIP(2)))* (1./sumchi2); 
-       Float_t *weight = GetWeight(tindex);
-       
-       if (weight){
-         *weight+= (1./(0.3+track->GetChi2MIP(1)+track->GetChi2MIP(2)))* (1./sumchi2);
-       }
-      }
-    }
-    
-    if (besttrack->GetChi2()/besttrack->GetNumberOfClusters()>3.5) return besttrack; //don't sign clusters
-    Int_t current=0;
-    Double_t deltad = besttrack->GetD(GetX(),GetY());
-    Double_t deltaz = besttrack->GetZat(GetX()) - GetZ();
-    Double_t deltaprim = TMath::Sqrt(deltad*deltad+deltaz*deltaz);
-
-    for (Int_t icluster=0;icluster<besttrack->GetNumberOfClusters();icluster++){
-      Int_t index = besttrack->GetClusterIndex(icluster);
-      Int_t ilayer =  (index & 0xf0000000) >> 28;
-      AliITSclusterV2 *c = (AliITSclusterV2*)GetCluster(index);
-      if (!c) continue;
-      // 
-      for (Int_t icluster=0;icluster<100;icluster++){
-       // sign non "doubt" clusters as used
-       if (clusterindex[ilayer][icluster]!=index) continue;
-       //      Float_t * weight = GetWeight(index);
-       //if (weight) if (*weight>1){
-       //  if (c->IsUsed()) continue;
-       //  c->Use();
-       //}      
-       if ( (ilayer*0.2+0.2)<deltaprim) continue; // secondaries
-       if (c->GetNy()>4) continue; // don sign cluster
-       if ( (ilayer>1&&clusterweight[ilayer][icluster]>0.7) || (ilayer<2&&clusterweight[ilayer][icluster]>0.8) ){
-         current++;
-         if (c->IsUsed()) continue;
-         c->Use();
-       }
-      }
-    }
-  }
-  //
-  return besttrack;
-} 
-
-
-AliITStrackV2 * AliITStrackerV2::GetBestHypothesysMIP(Int_t esdindex, AliITStrackV2 * original)
-{
-  //-------------------------------------------------------------
-  // try to find best hypothesy
-  // currently - minimal chi2 of track+backpropagated track+matching to the tpc track
-  //-------------------------------------------------------------
-  if (fTrackHypothesys.GetEntriesFast()<=esdindex) return 0;
-  TObjArray * array = (TObjArray*) fTrackHypothesys.At(esdindex);
-  if (!array) return 0;
-  Int_t entries = array->GetEntriesFast();
-  if (!entries) return 0;  
-  AliITStrackV2 * besttrack=0;
-  //
-  //sign usage information for clusters
-  Int_t clusterindex[6][100];
-  Double_t clusterweight[6][100];
-  for (Int_t ilayer=0;ilayer<6;ilayer++)
-    for (Int_t icluster=0;icluster<100;icluster++){
-      clusterindex[ilayer][icluster]   = -1;
-      clusterweight[ilayer][icluster]  = 0;
-    }
-  //printf("%d\t%d\n",esdindex, entries);
-  //
-  Float_t sumchi2=0;
-  for (Int_t itrack=0;itrack<entries; itrack++){
-    AliITStrackV2 * track = (AliITStrackV2*)array->At(itrack);
-    if (!track) continue;
-    if (track->GetChi2MIP(1)>1000) continue;  //not accepted - before
-    sumchi2 +=1./(0.3+track->GetChi2MIP(1)+track->GetChi2MIP(2));
-  }
-  //
-  // get cluster weight 
-  for (Int_t itrack=0;itrack<entries;itrack++){
-    AliITStrackV2 * track = (AliITStrackV2*)array->At(itrack);
-    if (!track) continue;
-    if (track->GetChi2MIP(1)>1000) continue;  // track not accepted in previous iterration  
-    for (Int_t icluster=0;icluster<track->GetNumberOfClusters();icluster++){     
-      Int_t tindex = track->GetClusterIndex(icluster);
-      Int_t ilayer = (tindex & 0xf0000000) >> 28;
-      if (tindex<0) continue;
-      Int_t cindex =0;
-      //
-      for (cindex=0;cindex<100;cindex++){
-       if (clusterindex[ilayer][cindex]<0) break;
-       if (clusterindex[ilayer][cindex]==tindex) break;
-      }
-      if (cindex>100) break;
-      if (clusterindex[ilayer][cindex]!=tindex) clusterindex[ilayer][cindex] = tindex;
-      clusterweight[ilayer][cindex]+= (1./(0.3+track->GetChi2MIP(1)+track->GetChi2MIP(2)))* (1./sumchi2); 
-    }
-  }
-  //  
-  // get cluster relative sharing - factor
-  //
-  // 
-  for (Int_t ilayer=0;ilayer<6;ilayer++)
-    for (Int_t cindex=0;cindex<100;cindex++){
-      if (clusterindex[ilayer][cindex]<0) continue;
-      Int_t tindex = clusterindex[ilayer][cindex];
-      Float_t *weight = GetWeight(tindex);
-      if (!weight){
-       printf("Problem 1\n");  // not existing track
-       continue;
-      }
-      if (*weight<(clusterweight[ilayer][cindex]-0.00001)){
-       printf("Problem 2\n");  // not normalized probability
-       continue;
-      }   
-      AliITSclusterV2 *c = (AliITSclusterV2*)GetCluster(tindex);
-      if (c->GetNy()<5){
-       clusterweight[ilayer][cindex]/= *weight; 
-      }
-      else{
-       Float_t weight2 = TMath::Max(*weight-0.5*clusterweight[ilayer][cindex],0.0000001);
-       clusterweight[ilayer][cindex]/= weight2;
-       if (    clusterweight[ilayer][cindex]>1)   clusterweight[ilayer][cindex] =1.;
-      }
-    }
-  //
-  //take to the account sharing factor
-  //
-  Float_t chi2 =10000000;
-  Float_t sharefactor=0;
-  Float_t minchi2 = 100000000;
-  Float_t secchi2 = 100000000;
-  Float_t norm=0;
-  for (Int_t itrack=0;itrack<entries; itrack++){
-    AliITStrackV2 * track = (AliITStrackV2*)array->At(itrack);
-    if (!track) continue;
-    if (track->GetChi2MIP(1)>1000) continue;  //not accepted - before
-    chi2 = track->GetChi2MIP(1);
-    Float_t newchi2=0;
-    sharefactor=0;
-    norm =0;
-    //
-    for (Int_t icluster=0;icluster<track->GetNumberOfClusters();icluster++){     
-      Int_t tindex = track->GetClusterIndex(icluster);
-      Int_t ilayer = (tindex & 0xf0000000) >> 28;
-      if (tindex<0) continue;
-      Int_t cindex =0;
-      Float_t cchi2 = (track->GetDy(ilayer)*track->GetDy(ilayer))/(track->GetSigmaY(ilayer)*track->GetSigmaY(ilayer)) +
-       (track->GetDz(ilayer)*track->GetDz(ilayer))/(track->GetSigmaZ(ilayer)*track->GetSigmaZ(ilayer)) ;
-      //
-      for (cindex=0;cindex<100;cindex++){
-       if (clusterindex[ilayer][cindex]<0) break;
-       if (clusterindex[ilayer][cindex]==tindex) break;
-      }
-      if (cindex>100) continue;
-      if (clusterweight[ilayer][cindex]>0.00001){
-       sharefactor+= clusterweight[ilayer][cindex];
-       cchi2/=clusterweight[ilayer][cindex];
-       norm++;
-      }
-      newchi2+=cchi2;
-    }
-    newchi2/=(norm-track->GetNSkipped()-track->GetNUsed());
-    track->SetChi2MIP(4,newchi2);
-    //if (norm>0) sharefactor/=norm;
-    //if (sharefactor<0.5) return 0;
-    //    chi2*=1./(0.5+sharefactor);
-    if (newchi2<minchi2){
-      besttrack = track;
-      minchi2   = newchi2;
-    }
-    else{
-      if (newchi2<secchi2){
-       secchi2 = newchi2;
-      }
-    }
-    //
-  }
-
-  //
-  //
-  if (!besttrack || besttrack->GetNumberOfClusters()<4) {
-    return 0;
-  }
-  //
-  if ((minchi2/secchi2)<0.7){
-    //
-    //increase the weight for clusters if the probability of other hypothesys is small
-    Double_t deltad = besttrack->GetD(GetX(),GetY());
-    Double_t deltaz = besttrack->GetZat(GetX()) - GetZ();
-    Double_t deltaprim = TMath::Sqrt(deltad*deltad+deltaz*deltaz);
-    //
-    for (Int_t icluster=0;icluster<besttrack->GetNumberOfClusters();icluster++){
-      Int_t index = besttrack->GetClusterIndex(icluster);
-      Int_t ilayer =  (index & 0xf0000000) >> 28;
-      AliITSclusterV2 *c = (AliITSclusterV2*)GetCluster(index);
-      if (!c) continue; 
-      if (c->GetNy()>3) continue;
-      if ( (ilayer*0.2+0.2)<deltaprim) continue; // secondaries     
-      Float_t * weight = GetWeight(index);
-      *weight*=2.;
-      *weight+=1.;
-    }   
-  }
-  
-
-  besttrack->SetLabel(original->GetLabel());
-  CookLabel(besttrack,0.0);
-  
-  //
-  return besttrack;
-} 
-