X-Git-Url: http://git.uio.no/git/?a=blobdiff_plain;f=ITS%2FAliITStrackerV2.cxx;h=7f30f46fd0bd6923325811d5e573a4bf3d4bfa9a;hb=f2649dd2a600ac50f4a40d9042b71d7194353e97;hp=75a7168de127dc6cb465047aa0a8f47bfdd3c6e9;hpb=f29dbb4b46823753f7dddb03041c7466814ebba4;p=u%2Fmrichter%2FAliRoot.git

diff --git a/ITS/AliITStrackerV2.cxx b/ITS/AliITStrackerV2.cxx
index 75a7168de12..7f30f46fd0b 100644
--- a/ITS/AliITStrackerV2.cxx
+++ b/ITS/AliITStrackerV2.cxx
@@ -15,30 +15,26 @@
 
 //-------------------------------------------------------------------------
 //               Implementation of the ITS tracker class
-//
+//    It reads AliITSclusterV2 clusters and creates AliITStrackV2 tracks
+//                   and fills with them the ESD
 //          Origin: Iouri Belikov, CERN, Jouri.Belikov@cern.ch
 //     dEdx analysis by: Boris Batyunya, JINR, Boris.Batiounia@cern.ch
 //-------------------------------------------------------------------------
 
-#include <stdlib.h>
 #include <TFile.h>
 #include <TTree.h>
 #include <TRandom.h>
-#include <Riostream.h>
 
 #include "AliITSgeom.h"
 #include "AliITSRecPoint.h"
 #include "AliTPCtrack.h"
+#include "AliESD.h"
 #include "AliITSclusterV2.h"
 #include "AliITStrackerV2.h"
 
-//#define DEBUG
+ClassImp(AliITStrackerV2)
 
-#ifdef DEBUG
-Int_t LAB=113;
-#endif
-
-AliITStrackerV2::AliITSlayer AliITStrackerV2::fLayers[kMaxLayer]; // ITS layers
+AliITStrackerV2::AliITSlayer AliITStrackerV2::fgLayers[kMaxLayer]; // ITS layers
 
 AliITStrackerV2::AliITStrackerV2(const AliITSgeom *geom) : AliTracker() {
   //--------------------------------------------------------------------
@@ -65,18 +61,20 @@ AliITStrackerV2::AliITStrackerV2(const AliITSgeom *geom) : AliTracker() {
     r += TMath::Sqrt(x*x + y*y);
     r*=0.25;
 
-    new (fLayers+i-1) AliITSlayer(r,poff,zoff,nlad,ndet);
+    new (fgLayers+i-1) AliITSlayer(r,poff,zoff,nlad,ndet);
 
     for (Int_t j=1; j<nlad+1; j++) {
       for (Int_t k=1; k<ndet+1; k++) { //Fill this layer with detectors
         Float_t x,y,zshift; g->GetTrans(i,j,k,x,y,zshift); 
         Double_t rot[9]; g->GetRotMatrix(i,j,k,rot);
 
-        Double_t r =-x*rot[1] + y*rot[0];         if (i==1) r=-r;
-        Double_t phi=TMath::ATan2(rot[1],rot[0]); if (i==1) phi-=3.1415927;
-        phi+=0.5*TMath::Pi(); if (phi<0) phi += 2*TMath::Pi();
-        AliITSdetector &det=fLayers[i-1].GetDetector((j-1)*ndet + k-1); 
+        Double_t phi=TMath::ATan2(rot[1],rot[0])+TMath::Pi();
+        phi+=TMath::Pi()/2;
+        if (i==1) phi+=TMath::Pi();
+        Double_t cp=TMath::Cos(phi), sp=TMath::Sin(phi);
+        Double_t r=x*cp+y*sp;
 
+        AliITSdetector &det=fgLayers[i-1].GetDetector((j-1)*ndet + k-1); 
         new(&det) AliITSdetector(r,phi); 
       } 
     }  
@@ -87,23 +85,30 @@ AliITStrackerV2::AliITStrackerV2(const AliITSgeom *geom) : AliTracker() {
 
   fPass=0;
   fConstraint[0]=1; fConstraint[1]=0;
+
+  Double_t xyz[]={kXV,kYV,kZV}, ers[]={kSigmaXV,kSigmaYV,kSigmaZV}; 
+  SetVertex(xyz,ers);
+
+  for (Int_t i=0; i<kMaxLayer; i++) fLayersNotToSkip[i]=kLayersNotToSkip[i];
+  fLastLayerToTrackTo=kLastLayerToTrackTo;
+
 }
 
-void AliITStrackerV2::LoadClusters() {
+void AliITStrackerV2::SetLayersNotToSkip(Int_t *l) {
+  //--------------------------------------------------------------------
+  //This function set masks of the layers which must be not skipped
+  //--------------------------------------------------------------------
+  for (Int_t i=0; i<kMaxLayer; i++) fLayersNotToSkip[i]=l[i];
+}
+
+Int_t AliITStrackerV2::LoadClusters(TTree *cTree) {
   //--------------------------------------------------------------------
   //This function loads ITS clusters
   //--------------------------------------------------------------------
-  char   cname[100]; 
-  sprintf(cname,"TreeC_ITS_%d",GetEventNumber());
-  TTree *cTree=(TTree*)gDirectory->Get(cname);
-  if (!cTree) { 
-    cerr<<"AliITStrackerV2::LoadClusters can't get cTree !\n";
-    exit(1);
-  }
   TBranch *branch=cTree->GetBranch("Clusters");
   if (!branch) { 
-    cerr<<"AliITStrackerV2::LoadClusters can't get Clusters branch !\n";
-    exit(1);
+    Error("LoadClusters"," can't get the branch !\n");
+    return 1;
   }
 
   TClonesArray dummy("AliITSclusterV2",10000), *clusters=&dummy;
@@ -111,125 +116,211 @@ void AliITStrackerV2::LoadClusters() {
 
   Int_t j=0;
   for (Int_t i=0; i<kMaxLayer; i++) {
-    Int_t jmax = j + fLayers[i].GetNladders()*fLayers[i].GetNdetectors();
+    Int_t ndet=fgLayers[i].GetNdetectors();
+    Int_t jmax = j + fgLayers[i].GetNladders()*ndet;
     for (; j<jmax; j++) {           
       if (!cTree->GetEvent(j)) continue;
       Int_t ncl=clusters->GetEntriesFast();
       while (ncl--) {
         AliITSclusterV2 *c=(AliITSclusterV2*)clusters->UncheckedAt(ncl);
-
-#ifdef DEBUG
-if (c->GetLabel(2)!=LAB)
-if (c->GetLabel(1)!=LAB)
-if (c->GetLabel(0)!=LAB) continue;
-cout<<lay-1<<' '<<lad-1<<' '<<det-1<<' '<<c->GetY()<<' '<<c->GetZ()<<endl;
-#endif
-
-        fLayers[i].InsertCluster(new AliITSclusterV2(*c));
+        fgLayers[i].InsertCluster(new AliITSclusterV2(*c));
       }
       clusters->Delete();
     }
+    fgLayers[i].ResetRoad(); //road defined by the cluster density
   }
-  delete cTree; //Thanks to Mariana Bondila
+
+  return 0;
 }
 
 void AliITStrackerV2::UnloadClusters() {
   //--------------------------------------------------------------------
   //This function unloads ITS clusters
   //--------------------------------------------------------------------
-  for (Int_t i=0; i<kMaxLayer; i++) fLayers[i].ResetClusters();
+  for (Int_t i=0; i<kMaxLayer; i++) fgLayers[i].ResetClusters();
 }
 
-//#ifdef DEBUG
-static Int_t lbl;
-//#endif
+static Int_t CorrectForDeadZoneMaterial(AliITStrackV2 *t) {
+  //--------------------------------------------------------------------
+  // Correction for the material between the TPC and the ITS
+  // (should it belong to the TPC code ?)
+  //--------------------------------------------------------------------
+  Double_t riw=80., diw=0.0053, x0iw=30; // TPC inner wall ? 
+  Double_t rcd=61., dcd=0.0053, x0cd=30; // TPC "central drum" ?
+  Double_t yr=12.8, dr=0.03; // rods ?
+  Double_t zm=0.2, dm=0.40;  // membrane
+  //Double_t rr=52., dr=0.19, x0r=24., yyr=7.77; //rails
+  Double_t rs=50., ds=0.001; // something belonging to the ITS (screen ?)
+
+  if (t->GetX() > riw) {
+     if (!t->PropagateTo(riw,diw,x0iw)) return 1;
+     if (TMath::Abs(t->GetY())>yr) t->CorrectForMaterial(dr);
+     if (TMath::Abs(t->GetZ())<zm) t->CorrectForMaterial(dm);
+     if (!t->PropagateTo(rcd,dcd,x0cd)) return 1;
+     //Double_t x,y,z; t->GetGlobalXYZat(rr,x,y,z);
+     //if (TMath::Abs(y)<yyr) t->PropagateTo(rr,dr,x0r); 
+     if (!t->PropagateTo(rs,ds)) return 1;
+  } else if (t->GetX() < rs) {
+     if (!t->PropagateTo(rs,-ds)) return 1;
+     //Double_t x,y,z; t->GetGlobalXYZat(rr,x,y,z);
+     //if (TMath::Abs(y)<yyr) t->PropagateTo(rr,-dr,x0r); 
+     if (!t->PropagateTo(rcd,-dcd,x0cd)) return 1;
+     if (!t->PropagateTo(riw+0.001,-diw,x0iw)) return 1;
+  } else {
+  ::Error("CorrectForDeadZoneMaterial","track is already in the dead zone !");
+    return 1;
+  }
+  
+  return 0;
+}
 
-Int_t AliITStrackerV2::Clusters2Tracks(const TFile *inp, TFile *out) {
+Int_t AliITStrackerV2::Clusters2Tracks(AliESD *event) {
   //--------------------------------------------------------------------
-  //This functions reconstructs ITS tracks
+  // This functions reconstructs ITS tracks
+  // The clusters must be already loaded !
   //--------------------------------------------------------------------
-  TFile *in=(TFile*)inp;
-  TDirectory *savedir=gDirectory; 
+  TObjArray itsTracks(15000);
+
+  {/* Read ESD tracks */
+    Int_t nentr=event->GetNumberOfTracks();
+    Info("Clusters2Tracks", "Number of ESD tracks: %d\n", nentr);
+    while (nentr--) {
+      AliESDtrack *esd=event->GetTrack(nentr);
+
+      if ((esd->GetStatus()&AliESDtrack::kTPCin)==0) continue;
+      if (esd->GetStatus()&AliESDtrack::kTPCout) continue;
+      if (esd->GetStatus()&AliESDtrack::kITSin) continue;
+
+      AliITStrackV2 *t=0;
+      try {
+        t=new AliITStrackV2(*esd);
+      } catch (const Char_t *msg) {
+        Warning("Clusters2Tracks",msg);
+        delete t;
+        continue;
+      }
+      if (TMath::Abs(t->GetD())>4) {
+	delete t;
+	continue;
+      }
 
-  LoadClusters();
+      if (CorrectForDeadZoneMaterial(t)!=0) {
+         Warning("Clusters2Tracks",
+                 "failed to correct for the material in the dead zone !\n");
+         delete t;
+         continue;
+      }
+      itsTracks.AddLast(t);
+    }
+  } /* End Read ESD tracks */
 
-  if (!in->IsOpen()) {
-     cerr<<"AliITStrackerV2::Clusters2Tracks(): ";
-     cerr<<"file with TPC tracks is not open !\n";
-     return 1;
-  }
+  itsTracks.Sort();
+  Int_t nentr=itsTracks.GetEntriesFast();
+
+  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++) {
+       AliITStrackV2 *t=(AliITStrackV2*)itsTracks.UncheckedAt(i);
+       if (t==0) continue;           //this track has been already tracked
+       Int_t tpcLabel=t->GetLabel(); //save the TPC track label
 
-  if (!out->IsOpen()) {
-     cerr<<"AliITStrackerV2::Clusters2Tracks(): ";
-     cerr<<"file for ITS tracks is not open !\n";
-     return 2;
+       ResetTrackToFollow(*t);
+       ResetBestTrack();
+
+       for (FollowProlongation(); fI<kMaxLayer; fI++) {
+          while (TakeNextProlongation()) FollowProlongation();
+       }
+
+       if (fBestTrack.GetNumberOfClusters() == 0) continue;
+
+       if (fConstraint[fPass]) {
+          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);
+       delete itsTracks.RemoveAt(i);
+       ntrk++;
+     }
   }
 
-  in->cd();
- 
-  Char_t tname[100];
+  itsTracks.Delete();
+
+  Info("Clusters2Tracks","Number of prolonged tracks: %d\n",ntrk);
+
+  return 0;
+}
+
+Int_t AliITStrackerV2::Clusters2Tracks(TTree *tpcTree, TTree *itsTree) {
+  //--------------------------------------------------------------------
+  // This functions reconstructs ITS tracks
+  // The clusters must be already loaded !
+  //--------------------------------------------------------------------
   Int_t nentr=0; TObjArray itsTracks(15000);
 
+   Warning("Clusters2Tracks(TTree *, TTree *)",
+      "Will be removed soon !   Use Clusters2Tracks(AliESD *) instead.");
+
   {/* Read TPC tracks */ 
-    sprintf(tname,"TreeT_TPC_%d",GetEventNumber());
-    TTree *tpcTree=(TTree*)in->Get(tname);
-    if (!tpcTree) {
-       cerr<<"AliITStrackerV2::Clusters2Tracks(): "
-             "can't get a tree with TPC tracks !\n";
-       return 3;
-    }
     AliTPCtrack *itrack=new AliTPCtrack; 
+    TBranch *branch=tpcTree->GetBranch("tracks");
+    if (!branch) {
+       Error("Clusters2Tracks","Can't get the branch !");
+       return 1;
+    }
     tpcTree->SetBranchAddress("tracks",&itrack);
     nentr=(Int_t)tpcTree->GetEntries();
+
+    Info("Clusters2Tracks","Number of TPC tracks: %d\n",nentr);
+
     for (Int_t i=0; i<nentr; i++) {
        tpcTree->GetEvent(i);
        AliITStrackV2 *t=0;
        try {
            t=new AliITStrackV2(*itrack);
        } catch (const Char_t *msg) {
-           cerr<<msg<<endl;
+           Warning("Clusters2Tracks",msg);
            delete t;
            continue;
        }
-       if (TMath::Abs(t->GetD())>4) continue;
+       if (TMath::Abs(t->GetD())>4) {
+	 delete t;
+	 continue;
+       }
 
-       t->PropagateTo(80.,0.0053,30);
-       if (TMath::Abs(t->GetY())>12.8) t->CorrectForMaterial(0.03);
-       if (TMath::Abs(t->GetZ())<0.2) t->CorrectForMaterial(0.40);
-       t->PropagateTo(61.,0.0053,30);
-       //Double_t xk=52.,x,y,z; t->GetGlobalXYZat(xk,x,y,z);
-       //if (TMath::Abs(y)<7.77) t->PropagateTo(xk,0.19,24.); 
-       t->PropagateTo(50.,0.001);
+       if (CorrectForDeadZoneMaterial(t)!=0) {
+	 Warning("Clusters2Tracks",
+                 "failed to correct for the material in the dead zone !\n");
+	 delete t;
+         continue;
+       }
 
        itsTracks.AddLast(t);
     }
-    delete tpcTree; //Thanks to Mariana Bondila
     delete itrack;
   }
   itsTracks.Sort();
+  nentr=itsTracks.GetEntriesFast();
 
-  out->cd();
 
-  sprintf(tname,"TreeT_ITS_%d",GetEventNumber());
-  TTree itsTree(tname,"Tree with ITS tracks");
   AliITStrackV2 *otrack=&fBestTrack;
-  itsTree.Branch("tracks","AliITStrackV2",&otrack,32000,0);
+  TBranch *branch=itsTree->GetBranch("tracks");
+  if (!branch) itsTree->Branch("tracks","AliITStrackV2",&otrack,32000,3);
+  else branch->SetAddress(&otrack);
 
   for (fPass=0; fPass<2; fPass++) {
      Int_t &constraint=fConstraint[fPass]; if (constraint<0) continue;
      for (Int_t i=0; i<nentr; i++) {
-       if (i%10==0) cerr<<nentr-i<<" \r";
        AliITStrackV2 *t=(AliITStrackV2*)itsTracks.UncheckedAt(i);
        if (t==0) continue;           //this track has been already tracked
        Int_t tpcLabel=t->GetLabel(); //save the TPC track label
 
-lbl=tpcLabel;
-#ifdef DEBUG
-lbl=tpcLabel;
-if (TMath::Abs(tpcLabel)!=LAB) continue;
-cout<<tpcLabel<<" *****************\n";
-#endif
-
        ResetTrackToFollow(*t);
        ResetBestTrack();
 
@@ -237,252 +328,167 @@ cout<<tpcLabel<<" *****************\n";
           while (TakeNextProlongation()) FollowProlongation();
        }
 
-#ifdef DEBUG
-cout<<fBestTrack.GetNumberOfClusters()<<" number of clusters\n\n";
-#endif
+       if (fBestTrack.GetNumberOfClusters() == 0) continue;
 
-      if (fBestTrack.GetNumberOfClusters() < kMaxLayer-kLayersToSkip) continue;
-
-        if (fConstraint[fPass]) {
-	   Int_t index[kMaxLayer];
-           Int_t k;
-           for (k=0; k<kMaxLayer; k++) index[k]=-1;
-           Int_t nc=fBestTrack.GetNumberOfClusters();
-           for (k=0; k<nc; k++) { 
-              Int_t idx=fBestTrack.GetClusterIndex(k),nl=(idx&0xf0000000)>>28;
-              index[nl]=idx; 
-           }
-           fBestTrack.~AliITStrackV2(); new(&fBestTrack) AliITStrackV2(*t);
-	   if (!RefitAt(3.7, &fBestTrack, index)) continue;
-	}
-
-        fBestTrack.SetLabel(tpcLabel);
-	fBestTrack.CookdEdx();
-        CookLabel(&fBestTrack,0.); //For comparison only
-            
-        fBestTrack.PropagateTo(3.,0.0028,65.19);
-        fBestTrack.PropagateToVertex();
-        
-        itsTree.Fill();
-        UseClusters(&fBestTrack);
-        delete itsTracks.RemoveAt(i);
+       if (fConstraint[fPass]) {
+          ResetTrackToFollow(*t);
+	  if (!RefitAt(3.7, &fTrackToFollow, &fBestTrack)) continue;
+          ResetBestTrack();
+       }
 
+       fBestTrack.SetLabel(tpcLabel);
+       fBestTrack.CookdEdx();
+       CookLabel(&fBestTrack,0.); //For comparison only
+       itsTree->Fill();
+       UseClusters(&fBestTrack);
+       delete itsTracks.RemoveAt(i);
      }
   }
 
-  itsTree.Write();
+  nentr=(Int_t)itsTree->GetEntries();
+  Info("Clusters2Tracks","Number of prolonged tracks: %d\n",nentr);
 
   itsTracks.Delete();
 
-  UnloadClusters();
-
-  savedir->cd();
-  cerr<<"Number of TPC tracks: "<<nentr<<endl;
-  cerr<<"Number of prolonged tracks: "<<itsTree.GetEntries()<<endl;
-
   return 0;
 }
 
-Int_t AliITStrackerV2::PropagateBack(const TFile *inp, TFile *out) {
+Int_t AliITStrackerV2::PropagateBack(AliESD *event) {
   //--------------------------------------------------------------------
-  //This functions propagates reconstructed ITS tracks back
+  // This functions propagates reconstructed ITS tracks back
+  // The clusters must be loaded !
   //--------------------------------------------------------------------
-  TFile *in=(TFile*)inp;
-  TDirectory *savedir=gDirectory; 
-
-  LoadClusters();
+  Int_t nentr=event->GetNumberOfTracks();
+  Info("PropagateBack", "Number of ESD tracks: %d\n", nentr);
 
-  if (!in->IsOpen()) {
-     cerr<<"AliITStrackerV2::PropagateBack(): ";
-     cerr<<"file with ITS tracks is not open !\n";
-     return 1;
-  }
+  Int_t ntrk=0;
+  for (Int_t i=0; i<nentr; i++) {
+     AliESDtrack *esd=event->GetTrack(i);
+
+     if ((esd->GetStatus()&AliESDtrack::kITSin)==0) continue;
+     if (esd->GetStatus()&AliESDtrack::kITSout) continue;
+
+     AliITStrackV2 *t=0;
+     try {
+        t=new AliITStrackV2(*esd);
+     } catch (const Char_t *msg) {
+        Warning("PropagateBack",msg);
+        delete t;
+        continue;
+     }
 
-  if (!out->IsOpen()) {
-     cerr<<"AliITStrackerV2::PropagateBack(): ";
-     cerr<<"file for back propagated ITS tracks is not open !\n";
-     return 2;
-  }
+     ResetTrackToFollow(*t);
 
-  in->cd();
+     // propagete to vertex [SR, GSI 17.02.2003]
+     // Start Time measurement [SR, GSI 17.02.2003], corrected by I.Belikov
+     if (fTrackToFollow.PropagateTo(3.,0.0028,65.19)) {
+       if (fTrackToFollow.PropagateToVertex()) {
+          fTrackToFollow.StartTimeIntegral();
+       }
+       fTrackToFollow.PropagateTo(3.,-0.0028,65.19);
+     }
 
-  Char_t tname[100];
-  sprintf(tname,"TreeT_ITS_%d",GetEventNumber());
-  TTree *itsTree=(TTree*)in->Get(tname);
-  if (!itsTree) {
-     cerr<<"AliITStrackerV2::PropagateBack() ";
-     cerr<<"can't get a tree with ITS tracks !\n";
-     return 3;
+     fTrackToFollow.ResetCovariance(); fTrackToFollow.ResetClusters();
+     if (RefitAt(49.,&fTrackToFollow,t)) {
+        if (CorrectForDeadZoneMaterial(&fTrackToFollow)!=0) {
+          Warning("PropagateBack",
+                  "failed to correct for the material in the dead zone !\n");
+          delete t;
+          continue;
+        }
+        fTrackToFollow.SetLabel(t->GetLabel());
+        //fTrackToFollow.CookdEdx();
+        CookLabel(&fTrackToFollow,0.); //For comparison only
+        fTrackToFollow.UpdateESDtrack(AliESDtrack::kITSout);
+        UseClusters(&fTrackToFollow);
+        ntrk++;
+     }
+     delete t;
   }
-  AliITStrackV2 *itrack=new AliITStrackV2; 
-  itsTree->SetBranchAddress("tracks",&itrack);
 
-  out->cd();
+  Info("PropagateBack","Number of back propagated ITS tracks: %d\n",ntrk);
 
-  sprintf(tname,"TreeT_ITSb_%d",GetEventNumber());
-  TTree backTree(tname,"Tree with back propagated ITS tracks");
-  AliTPCtrack *otrack=0;
-  backTree.Branch("tracks","AliTPCtrack",&otrack,32000,2);
+  return 0;
+}
 
-  Int_t ntrk=0;
+Int_t AliITStrackerV2::RefitInward(AliESD *event) {
+  //--------------------------------------------------------------------
+  // This functions refits ITS tracks using the 
+  // "inward propagated" TPC tracks
+  // The clusters must be loaded !
+  //--------------------------------------------------------------------
+  Int_t nentr=event->GetNumberOfTracks();
+  Info("RefitInward", "Number of ESD tracks: %d\n", nentr);
 
-  Int_t nentr=(Int_t)itsTree->GetEntries();
+  Int_t ntrk=0;
   for (Int_t i=0; i<nentr; i++) {
+    AliESDtrack *esd=event->GetTrack(i);
 
-    itsTree->GetEvent(i);
-    ResetTrackToFollow(*itrack);
-
-    // propagete to vertex [SR, GSI 17.02.2003]
-    fTrackToFollow.PropagateTo(3.,0.0028,65.19);
-    fTrackToFollow.PropagateToVertex();
-
-    // Start Time measurement [SR, GSI 17.02.2003]
-    fTrackToFollow.StartTimeIntegral();
-    fTrackToFollow.PropagateTo(3.,-0.0028,65.19);
-    //
-
-    fTrackToFollow.ResetCovariance(); 
-    fTrackToFollow.ResetClusters();
-
-    Int_t itsLabel=fTrackToFollow.GetLabel(); //save the ITS track label
-
-#ifdef DEBUG
-if (TMath::Abs(itsLabel)!=LAB) continue;
-cout<<itsLabel<<" *****************\n";
-#endif
+    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;
 
+    AliITStrackV2 *t=0;
     try {
-       Int_t nc=itrack->GetNumberOfClusters();
-#ifdef DEBUG
-for (Int_t k=0; k<nc; k++) {
-    Int_t index=itrack->GetClusterIndex(k);
-    AliITSclusterV2 *c=(AliITSclusterV2*)GetCluster(index);
-    cout<<c->GetLabel(0)<<' '<<c->GetLabel(1)<<' '<<c->GetLabel(2)<<endl;
-}
-#endif       
-       Int_t idx=0, l=0; 
-       const  AliITSclusterV2 *c=0; 
-       if (nc--) {
-          idx=itrack->GetClusterIndex(nc); l=(idx&0xf0000000)>>28;
-          c=(AliITSclusterV2*)GetCluster(idx);
-       }
-       for (fI=0; fI<kMaxLayer; fI++) {
-         AliITSlayer &layer=fLayers[fI];
-         Double_t r=layer.GetR();
-         if (fI==2 || fI==4) {             
-            Double_t rs=0.5*(fLayers[fI-1].GetR() + r);
-            Double_t d=0.0034, x0=38.6;
-            if (fI==2) {rs=9.; d=0.0097; x0=42.;}
-            if (!fTrackToFollow.PropagateTo(rs,-d,x0)) throw "";
-         }
+        t=new AliITStrackV2(*esd);
+    } catch (const Char_t *msg) {
+        Warning("RefitInward",msg);
+        delete t;
+        continue;
+    }
 
-         // remember old position [SR, GSI 18.02.2003]
-	 Double_t oldX, oldY, oldZ;
-	 fTrackToFollow.GetGlobalXYZat(fTrackToFollow.GetX(),oldX,oldY,oldZ);
-	 //
-
-         Double_t x,y,z;
-         if (!fTrackToFollow.GetGlobalXYZat(r,x,y,z)) 
-            throw "AliITStrackerV2::PropagateBack: failed to estimate track !";
-         Double_t phi=TMath::ATan2(y,x);
-         Int_t idet=layer.FindDetectorIndex(phi,z);
-         if (idet<0) 
-         throw "AliITStrackerV2::PropagateBack: failed to find a detector !\n";
-         const AliITSdetector &det=layer.GetDetector(idet);
-         r=det.GetR(); phi=det.GetPhi();
-         if (!fTrackToFollow.Propagate(phi,r)) throw "";
-         fTrackToFollow.SetDetectorIndex(idet);
-
-         const AliITSclusterV2 *cl=0;
-         Int_t index=0;
-         Double_t maxchi2=kMaxChi2;
-
-         if (l==fI) {
-           idet=c->GetDetectorIndex();
-           if (idet != fTrackToFollow.GetDetectorIndex()) {
-             const AliITSdetector &det=layer.GetDetector(idet);
-             r=det.GetR(); phi=det.GetPhi();
-             if (!fTrackToFollow.Propagate(phi,r)) throw "";
-             fTrackToFollow.SetDetectorIndex(idet);
-           }
-           Double_t chi2=fTrackToFollow.GetPredictedChi2(c);
-           if (chi2<kMaxChi2) {
-              cl=c; maxchi2=chi2; index=idx;
-           }
-           if (nc--) {
-              idx=itrack->GetClusterIndex(nc); l=(idx&0xf0000000)>>28;
-              c=(AliITSclusterV2*)GetCluster(idx);
-           } 
-         }
+    if (CorrectForDeadZoneMaterial(t)!=0) {
+       Warning("RefitInward",
+               "failed to correct for the material in the dead zone !\n");
+       delete t;
+       continue;
+    }
 
-         if (fTrackToFollow.GetNumberOfClusters()>2) {
-           Double_t dz=3*TMath::Sqrt(fTrackToFollow.GetSigmaZ2()+kSigmaZ2[fI]);
-           Double_t dy=3*TMath::Sqrt(fTrackToFollow.GetSigmaY2()+kSigmaY2[fI]);
-           Double_t zmin=fTrackToFollow.GetZ() - dz;
-           Double_t zmax=fTrackToFollow.GetZ() + dz;
-           Double_t ymin=fTrackToFollow.GetY() + phi*r - dy;
-           Double_t ymax=fTrackToFollow.GetY() + phi*r + dy;
-           layer.SelectClusters(zmin,zmax,ymin,ymax);
-
-           const AliITSclusterV2 *cc=0; Int_t ci;
-           while ((cc=layer.GetNextCluster(ci))!=0) {
-              idet=cc->GetDetectorIndex();
-              if (idet != fTrackToFollow.GetDetectorIndex()) continue;
-              Double_t chi2=fTrackToFollow.GetPredictedChi2(cc);
-              if (chi2<maxchi2) {
-                 cl=cc; index=(fI<<28)+ci; maxchi2=chi2;
-              }
-           }
-         }
+    ResetTrackToFollow(*t);
+    fTrackToFollow.ResetClusters();
 
-         if (cl) {
-           if (!fTrackToFollow.Update(cl,maxchi2,index)) 
-             cerr<<"AliITStrackerV2::PropagateBack: filtering failed !\n";
-         }
-         {
-           Double_t x0;
-           x=layer.GetThickness(fTrackToFollow.GetY(),fTrackToFollow.GetZ(),x0);
-           fTrackToFollow.CorrectForMaterial(-x,x0); 
+    //Refitting...
+    if (RefitAt(3.7, &fTrackToFollow, t)) {
+       fTrackToFollow.SetLabel(t->GetLabel());
+       fTrackToFollow.CookdEdx();
+       CookLabel(&fTrackToFollow,0.); //For comparison only
+
+       if (fTrackToFollow.PropagateTo(3.,0.0028,65.19)) {//The beam pipe    
+         Double_t a=fTrackToFollow.GetAlpha();
+         Double_t cs=TMath::Cos(a),sn=TMath::Sin(a);
+         Double_t xv= GetX()*cs + GetY()*sn;
+         Double_t yv=-GetX()*sn + GetY()*cs;
+         
+         Double_t c=fTrackToFollow.GetC(), snp=fTrackToFollow.GetSnp();
+         Double_t x=fTrackToFollow.GetX(), y=fTrackToFollow.GetY();
+         Double_t tgfv=-(c*(x-xv)-snp)/(c*(y-yv) + TMath::Sqrt(1.-snp*snp));
+         Double_t fv=TMath::ATan(tgfv);
+
+         cs=TMath::Cos(fv); sn=TMath::Sin(fv);
+         x = xv*cs + yv*sn;
+         yv=-xv*sn + yv*cs; xv=x;
+
+	 if (fTrackToFollow.Propagate(fv+a,xv)) {
+            fTrackToFollow.UpdateESDtrack(AliESDtrack::kITSrefit);
+            UseClusters(&fTrackToFollow);
+            {
+            AliITSclusterV2 c; c.SetY(yv); c.SetZ(GetZ());
+            c.SetSigmaY2(GetSigmaY()*GetSigmaY());
+            c.SetSigmaZ2(GetSigmaZ()*GetSigmaZ());
+            Double_t chi2=fTrackToFollow.GetPredictedChi2(&c);
+            if (chi2<kMaxChi2)
+	       if (fTrackToFollow.Update(&c,-chi2,0))
+                   fTrackToFollow.SetConstrainedESDtrack(chi2);            
+            }
+            ntrk++;
          }
-         	 
-         // track time update [SR, GSI 17.02.2003]
-         Double_t newX, newY, newZ;
-	 fTrackToFollow.GetGlobalXYZat(fTrackToFollow.GetX(),newX,newY,newZ);
-         Double_t dL2 = (oldX-newX)*(oldX-newX)+(oldY-newY)*(oldY-newY)+(oldZ-newZ)*(oldZ-newZ);
-	 fTrackToFollow.AddTimeStep(TMath::Sqrt(dL2));
-         //
-
        }
-
-       fTrackToFollow.PropagateTo(50.,-0.001);
-       //Double_t xk=52.,x,y,z; fTrackToFollow.GetGlobalXYZat(xk,x,y,z);
-       //if (TMath::Abs(y)<7.77) fTrackToFollow.PropagateTo(xk,-0.19,24.); 
-       fTrackToFollow.PropagateTo(61,-0.0053,30);
-       fTrackToFollow.PropagateTo(80.,-0.0053,30);
-
-       fTrackToFollow.SetLabel(itsLabel);
-       otrack=new AliTPCtrack(fTrackToFollow,fTrackToFollow.GetAlpha()); 
-       backTree.Fill(); delete otrack;
-       UseClusters(&fTrackToFollow);
-       cerr << ++ntrk << "                \r";
-    }
-    catch (const Char_t *msg) {
-       cerr<<msg<<endl;
     }
+    delete t;
   }
 
-  backTree.Write();
-
-  cerr<<"Number of ITS tracks: "<<nentr<<endl;
-  cerr<<"Number of back propagated ITS tracks: "<<ntrk<<endl;
-
-  delete itrack;
-
-  delete itsTree; //Thanks to Mariana Bondila
-
-  UnloadClusters();
-
-  savedir->cd();
+  Info("RefitInward","Number of refitted tracks: %d\n",ntrk);
 
   return 0;
 }
@@ -493,7 +499,7 @@ AliCluster *AliITStrackerV2::GetCluster(Int_t index) const {
   //--------------------------------------------------------------------
   Int_t l=(index & 0xf0000000) >> 28;
   Int_t c=(index & 0x0fffffff) >> 00;
-  return fLayers[l].GetCluster(c);
+  return fgLayers[l].GetCluster(c);
 }
 
 
@@ -501,69 +507,71 @@ void AliITStrackerV2::FollowProlongation() {
   //--------------------------------------------------------------------
   //This function finds a track prolongation 
   //--------------------------------------------------------------------
-  Int_t tryAgain=kLayersToSkip;
-
-  while (fI) {
+  while (fI>fLastLayerToTrackTo) {
     Int_t i=fI-1;
-#ifdef DEBUG
-cout<<i<<' ';
-#endif
-    AliITSlayer &layer=fLayers[i];
+
+    AliITSlayer &layer=fgLayers[i];
     AliITStrackV2 &track=fTracks[i];
 
     Double_t r=layer.GetR();
 
     if (i==3 || i==1) {
-       Double_t rs=0.5*(fLayers[i+1].GetR() + r);
+       Double_t rs=0.5*(fgLayers[i+1].GetR() + r);
        Double_t d=0.0034, x0=38.6;
        if (i==1) {rs=9.; d=0.0097; x0=42;}
        if (!fTrackToFollow.PropagateTo(rs,d,x0)) {
-	 //cerr<<"AliITStrackerV2::FollowProlongation: "
-         //"propagation failed !\n";
-         break;
+	 //Warning("FollowProlongation","propagation failed !\n");
+         return;
        }
     }
 
     //find intersection
     Double_t x,y,z;  
     if (!fTrackToFollow.GetGlobalXYZat(r,x,y,z)) {
-      //cerr<<"AliITStrackerV2::FollowProlongation: "
-      //"failed to estimate track !\n";
-      break;
+      //Warning("FollowProlongation","failed to estimate track !\n");
+      return;
     }
     Double_t phi=TMath::ATan2(y,x);
+
     Int_t idet=layer.FindDetectorIndex(phi,z);
     if (idet<0) {
-      //cerr<<"AliITStrackerV2::FollowProlongation: "
-      //"failed to find a detector !\n";
-      break;
+      //Warning("FollowProlongation","failed to find a detector !\n");
+      return;
     }
 
     //propagate to the intersection
     const AliITSdetector &det=layer.GetDetector(idet);
     phi=det.GetPhi();
     if (!fTrackToFollow.Propagate(phi,det.GetR())) {
-      //cerr<<"AliITStrackerV2::FollowProlongation: propagation failed !\n";
-      break;
+      //Warning("FollowProlongation","propagation failed !\n");
+      return;
     }
     fTrackToFollow.SetDetectorIndex(idet);
 
     //Select possible prolongations and store the current track estimation
     track.~AliITStrackV2(); new(&track) AliITStrackV2(fTrackToFollow);
-    Double_t dz=3*TMath::Sqrt(track.GetSigmaZ2() + kSigmaZ2[i]);
+    Double_t dz=7*TMath::Sqrt(track.GetSigmaZ2() + kSigmaZ2[i]);
+    Double_t dy=7*TMath::Sqrt(track.GetSigmaY2() + kSigmaY2[i]);
+    Double_t road=layer.GetRoad();
+    if (dz*dy>road*road) {
+       Double_t dd=TMath::Sqrt(dz*dy), scz=dz/dd, scy=dy/dd;
+       dz=road*scz; dy=road*scy;
+    } 
+
+    //Double_t dz=4*TMath::Sqrt(track.GetSigmaZ2() + kSigmaZ2[i]);
     if (dz < 0.5*TMath::Abs(track.GetTgl())) dz=0.5*TMath::Abs(track.GetTgl());
     if (dz > kMaxRoad) {
-      //cerr<<"AliITStrackerV2::FollowProlongation: too broad road in Z !\n";
-      break;
+      //Warning("FollowProlongation","too broad road in Z !\n");
+      return;
     }
 
-    if (TMath::Abs(fTrackToFollow.GetZ()-GetZ()) > r+dz) break;
+    if (TMath::Abs(fTrackToFollow.GetZ()-GetZ()) > r+dz) return;
 
-    Double_t dy=4*TMath::Sqrt(track.GetSigmaY2() + kSigmaY2[i]);
+    //Double_t dy=4*TMath::Sqrt(track.GetSigmaY2() + kSigmaY2[i]);
     if (dy < 0.5*TMath::Abs(track.GetSnp())) dy=0.5*TMath::Abs(track.GetSnp());
     if (dy > kMaxRoad) {
-      //cerr<<"AliITStrackerV2::FollowProlongation: too broad road in Y !\n";
-      break;
+      //Warning("FollowProlongation","too broad road in Y !\n");
+      return;
     }
 
     Double_t zmin=track.GetZ() - dz; 
@@ -574,8 +582,8 @@ cout<<i<<' ';
     fI--;
 
     //take another prolongation
-    if (!TakeNextProlongation()) if (!tryAgain--) break;
-    tryAgain=kLayersToSkip;
+    if (!TakeNextProlongation()) 
+       if (fLayersNotToSkip[fI]) return;
 
   } 
 
@@ -600,33 +608,31 @@ Int_t AliITStrackerV2::TakeNextProlongation() {
   //
   //  dEdx analysis by: Boris Batyunya, JINR, Boris.Batiounia@cern.ch 
   //--------------------------------------------------------------------
-  AliITSlayer &layer=fLayers[fI];
+  AliITSlayer &layer=fgLayers[fI];
   ResetTrackToFollow(fTracks[fI]);
 
-  Double_t dz=4*TMath::Sqrt(fTrackToFollow.GetSigmaZ2() + kSigmaZ2[fI]);
-  Double_t dy=4*TMath::Sqrt(fTrackToFollow.GetSigmaY2() + kSigmaY2[fI]);
+  Double_t dz=7*TMath::Sqrt(fTrackToFollow.GetSigmaZ2() + kSigmaZ2[fI]);
+  Double_t dy=7*TMath::Sqrt(fTrackToFollow.GetSigmaY2() + kSigmaY2[fI]);
+  Double_t road=layer.GetRoad();
+  if (dz*dy>road*road) {
+     Double_t dd=TMath::Sqrt(dz*dy), scz=dz/dd, scy=dy/dd;
+     dz=road*scz; dy=road*scy;
+  } 
 
   const AliITSclusterV2 *c=0; Int_t ci=-1;
   Double_t chi2=12345.;
   while ((c=layer.GetNextCluster(ci))!=0) {
-    //if (c->GetLabel(0)!=TMath::Abs(lbl)) continue; 
     Int_t idet=c->GetDetectorIndex();
 
     if (fTrackToFollow.GetDetectorIndex()!=idet) {
        const AliITSdetector &det=layer.GetDetector(idet);
        ResetTrackToFollow(fTracks[fI]);
        if (!fTrackToFollow.Propagate(det.GetPhi(),det.GetR())) {
-         //cerr<<"AliITStrackerV2::TakeNextProlongation: "
-         //"propagation failed !\n";
+         //Warning("TakeNextProlongation","propagation failed !\n");
          continue;
        }
        fTrackToFollow.SetDetectorIndex(idet);
        if (TMath::Abs(fTrackToFollow.GetZ()-GetZ())>layer.GetR()+dz) continue;
-
-#ifdef DEBUG
-cout<<fI<<" change detector !\n";
-#endif
-
     }
 
     if (TMath::Abs(fTrackToFollow.GetZ() - c->GetZ()) > dz) continue;
@@ -635,22 +641,11 @@ cout<<fI<<" change detector !\n";
     chi2=fTrackToFollow.GetPredictedChi2(c); if (chi2<kMaxChi2) break;
   }
 
-#ifdef DEBUG
-cout<<fI<<" chi2="<<chi2<<' '
-    <<fTrackToFollow.GetY()<<' '<<fTrackToFollow.GetZ()<<' '
-    <<dy<<' '<<dz<<endl;
-{
-Double_t phi=TMath::ATan(fTrackToFollow.GetY()/fTrackToFollow.GetX())
-            +fTrackToFollow.GetAlpha(); phi=phi*180./3.141593;
-cout<<phi<<endl;
-}
-#endif
-
   if (chi2>=kMaxChi2) return 0;
   if (!c) return 0;
 
   if (!fTrackToFollow.Update(c,chi2,(fI<<28)+ci)) {
-     //cerr<<"AliITStrackerV2::TakeNextProlongation: filtering failed !\n";
+     //Warning("TakeNextProlongation","filtering failed !\n");
      return 0;
   }
 
@@ -661,23 +656,18 @@ cout<<phi<<endl;
     SetSampledEdx(c->GetQ(),fTrackToFollow.GetNumberOfClusters()-1); //b.b.
 
   {
- Double_t x0;
+  Double_t x0;
  Double_t d=layer.GetThickness(fTrackToFollow.GetY(),fTrackToFollow.GetZ(),x0);
-   fTrackToFollow.CorrectForMaterial(d,x0);
+  fTrackToFollow.CorrectForMaterial(d,x0);
   }
 
   if (fConstraint[fPass]) {
     Double_t d=GetEffectiveThickness(0,0); //Think of this !!!!
-    fTrackToFollow.Improve(d,GetY(),GetZ());
+    Double_t xyz[]={GetX(),GetY(),GetZ()};
+    Double_t ers[]={GetSigmaX(),GetSigmaY(),GetSigmaZ()};
+    fTrackToFollow.Improve(d,xyz,ers);
   }
 
-#ifdef DEBUG
-cout<<"accepted lab="<<c->GetLabel(0)<<' '
-    <<fTrackToFollow.GetNumberOfClusters()<<' '
-    <<fTrackToFollow.GetY()<<' '<<fTrackToFollow.GetZ()<<' '
-    <<fTrackToFollow.Get1Pt()<<endl<<endl;
-#endif
-
   return 1;
 }
 
@@ -701,6 +691,8 @@ AliITSlayer(Double_t r,Double_t p,Double_t z,Int_t nl,Int_t nd) {
 
   fN=0;
   fI=0;
+
+  fRoad=2*fR*TMath::Sqrt(3.14/1.);//assuming that there's only one cluster
 }
 
 AliITStrackerV2::AliITSlayer::~AliITSlayer() {
@@ -720,14 +712,24 @@ void AliITStrackerV2::AliITSlayer::ResetClusters() {
   fI=0;
 }
 
+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++;
+  }
+  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
   //--------------------------------------------------------------------
   if (fN==kMaxClusterPerLayer) {
-     cerr<<"AliITStrackerV2::AliITSlayer::InsertCluster(): "
-           "Too many clusters !\n";
-     return 1;
+    ::Error("InsertCluster","Too many clusters !\n");
+    return 1;
   }
 
   if (fN==0) {fClusters[fN++]=c; return 0;}
@@ -794,7 +796,7 @@ FindDetectorIndex(Double_t phi, Double_t z) const {
   //--------------------------------------------------------------------
   //This function finds the detector crossed by the track
   //--------------------------------------------------------------------
-  Double_t dphi=phi-fPhiOffset;
+  Double_t dphi=-(phi-fPhiOffset);
   if      (dphi <  0) dphi += 2*TMath::Pi();
   else if (dphi >= 2*TMath::Pi()) dphi -= 2*TMath::Pi();
   Int_t np=Int_t(dphi*fNladders*0.5/TMath::Pi()+0.5);
@@ -806,10 +808,6 @@ FindDetectorIndex(Double_t phi, Double_t z) const {
   if (nz>=fNdetectors) return -1;
   if (nz<0)            return -1;
 
-#ifdef DEBUG
-cout<<np<<' '<<nz<<endl;
-#endif
-
   return np*fNdetectors + nz;
 }
 
@@ -912,10 +910,6 @@ const {
      if (TMath::Abs(y+0.10)<0.10) {d+=0.014;}
   }
 
-#ifdef DEBUG
-  cout<<"d="<<d<<endl;
-#endif
-
   return d;
 }
 
@@ -927,10 +921,10 @@ Double_t AliITStrackerV2::GetEffectiveThickness(Double_t y,Double_t z) const
   Double_t d=0.0028*3*3; //beam pipe
   Double_t x0=0;
 
-  Double_t xn=fLayers[fI].GetR();
+  Double_t xn=fgLayers[fI].GetR();
   for (Int_t i=0; i<fI; i++) {
-    Double_t xi=fLayers[i].GetR();
-    d+=fLayers[i].GetThickness(y,z,x0)*xi*xi;
+    Double_t xi=fgLayers[i].GetR();
+    d+=fgLayers[i].GetThickness(y,z,x0)*xi*xi;
   }
 
   if (fI>1) {
@@ -939,7 +933,7 @@ Double_t AliITStrackerV2::GetEffectiveThickness(Double_t y,Double_t z) const
   }
 
   if (fI>3) {
-    Double_t xi=0.5*(fLayers[3].GetR()+fLayers[4].GetR());
+    Double_t xi=0.5*(fgLayers[3].GetR()+fgLayers[4].GetR());
     d+=0.0034*xi*xi;
   }
 
@@ -968,12 +962,23 @@ Int_t AliITStrackerV2::AliITSlayer::InRoad() const {
   return ncl;
 }
 
-Bool_t AliITStrackerV2::RefitAt(Double_t x, AliITStrackV2 *t, Int_t *index) {
+Bool_t 
+AliITStrackerV2::RefitAt(Double_t xx,AliITStrackV2 *t,const AliITStrackV2 *c) {
   //--------------------------------------------------------------------
-  // This function refits a track at a given position
+  // This function refits the track "t" at the position "x" using
+  // the clusters from "c"
   //--------------------------------------------------------------------
+  Int_t index[kMaxLayer];
+  Int_t k;
+  for (k=0; k<kMaxLayer; k++) index[k]=-1;
+  Int_t nc=c->GetNumberOfClusters();
+  for (k=0; k<nc; k++) { 
+    Int_t idx=c->GetClusterIndex(k),nl=(idx&0xf0000000)>>28;
+    index[nl]=idx; 
+  }
+
   Int_t from, to, step;
-  if (x > t->GetX()) {
+  if (xx > t->GetX()) {
       from=0; to=kMaxLayer;
       step=+1;
   } else {
@@ -982,21 +987,28 @@ Bool_t AliITStrackerV2::RefitAt(Double_t x, AliITStrackV2 *t, Int_t *index) {
   }
 
   for (Int_t i=from; i != to; i += step) {
-     AliITSlayer &layer=fLayers[i];
+     AliITSlayer &layer=fgLayers[i];
      Double_t r=layer.GetR();
  
      {
      Double_t hI=i-0.5*step; 
-     if (hI==1.5 || hI==3.5) {             
-        Double_t rs=0.5*(fLayers[i-step].GetR() + r);
+     if (TMath::Abs(hI-1.5)<0.01 || TMath::Abs(hI-3.5)<0.01) {             
+        Double_t rs=0.5*(fgLayers[i-step].GetR() + r);
         Double_t d=0.0034, x0=38.6; 
-        if (hI==1.5) {rs=9.; d=0.0097; x0=42;}
-        if (!t->PropagateTo(rs,d,x0)) {
+        if (TMath::Abs(hI-1.5)<0.01) {rs=9.; d=0.0097; x0=42;}
+        if (!t->PropagateTo(rs,-step*d,x0)) {
           return kFALSE;
         }
      }
      }
 
+     // remember old position [SR, GSI 18.02.2003]
+     Double_t oldX=0., oldY=0., oldZ=0.;
+     if (t->IsStartedTimeIntegral() && step==1) {
+        t->GetGlobalXYZat(t->GetX(),oldX,oldY,oldZ);
+     }
+     //
+
      Double_t x,y,z;
      if (!t->GetGlobalXYZat(r,x,y,z)) { 
        return kFALSE;
@@ -1028,10 +1040,13 @@ Bool_t AliITStrackerV2::RefitAt(Double_t x, AliITStrackV2 *t, Int_t *index) {
            t->SetDetectorIndex(idet);
         }
         Double_t chi2=t->GetPredictedChi2(c);
-        if (chi2<maxchi2) { cl=c; maxchi2=chi2; }
-        else return kFALSE;
+        if (chi2<maxchi2) { 
+	  cl=c; 
+	  maxchi2=chi2; 
+	} else {
+	  return kFALSE;
+	}
      }
-
      /*
      if (cl==0)
      if (t->GetNumberOfClusters()>2) {
@@ -1051,11 +1066,11 @@ Bool_t AliITStrackerV2::RefitAt(Double_t x, AliITStrackV2 *t, Int_t *index) {
         }
      }
      */
-
      if (cl) {
        if (!t->Update(cl,maxchi2,idx)) {
           return kFALSE;
        }
+       t->SetSampledEdx(cl->GetQ(),t->GetNumberOfClusters()-1);
      }
 
      {
@@ -1063,12 +1078,34 @@ Bool_t AliITStrackerV2::RefitAt(Double_t x, AliITStrackV2 *t, Int_t *index) {
      Double_t d=layer.GetThickness(t->GetY(),t->GetZ(),x0);
      t->CorrectForMaterial(-step*d,x0);
      }
+                 
+     // track time update [SR, GSI 17.02.2003]
+     if (t->IsStartedTimeIntegral() && step==1) {
+        Double_t newX, newY, newZ;
+        t->GetGlobalXYZat(t->GetX(),newX,newY,newZ);
+        Double_t dL2 = (oldX-newX)*(oldX-newX) + (oldY-newY)*(oldY-newY) + 
+                       (oldZ-newZ)*(oldZ-newZ);
+        t->AddTimeStep(TMath::Sqrt(dL2));
+     }
+     //
 
   }
 
-  if (!t->PropagateTo(x,0.,0.)) return kFALSE;
+  if (!t->PropagateTo(xx,0.,0.)) return kFALSE;
   return kTRUE;
 }
 
+void AliITStrackerV2::UseClusters(const AliKalmanTrack *t, Int_t from) const {
+  //--------------------------------------------------------------------
+  // This function marks clusters assigned to the track
+  //--------------------------------------------------------------------
+  AliTracker::UseClusters(t,from);
 
+  AliITSclusterV2 *c=(AliITSclusterV2 *)GetCluster(t->GetClusterIndex(0));
+  //if (c->GetQ()>2) c->Use();
+  if (c->GetSigmaZ2()>0.1) c->Use();
+  c=(AliITSclusterV2 *)GetCluster(t->GetClusterIndex(1));
+  //if (c->GetQ()>2) c->Use();
+  if (c->GetSigmaZ2()>0.1) c->Use();
 
+}