X-Git-Url: http://git.uio.no/git/?a=blobdiff_plain;f=ITS%2FAliITStrackerV2.cxx;h=a1b1d6a2c5099c77776df72b390c4d00b5272709;hb=50f91c8bdc57f4d3b826ff69d617e2672177ed2a;hp=3b447b20266df4c2b8ce6d731f50e4a9204d2211;hpb=743a19f2b0103cdccad62e316effbd84ccb23b55;p=u%2Fmrichter%2FAliRoot.git

diff --git a/ITS/AliITStrackerV2.cxx b/ITS/AliITStrackerV2.cxx
index 3b447b20266..a1b1d6a2c50 100644
--- a/ITS/AliITStrackerV2.cxx
+++ b/ITS/AliITStrackerV2.cxx
@@ -12,447 +12,456 @@
  * about the suitability of this software for any purpose. It is          *
  * provided "as is" without express or implied warranty.                  *
  **************************************************************************/
-
+/* $Id$ */
 //-------------------------------------------------------------------------
 //               Implementation of the ITS tracker class
-//
+//    It reads AliITSRecPoint 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 <new>
+
+#include <TError.h>
 #include <TFile.h>
 #include <TTree.h>
 #include <TRandom.h>
-#include <iostream.h>
+#include <TGeoMatrix.h>
 
-#include "AliITSgeom.h"
+#include "AliITSgeomTGeo.h"
+#include "AliAlignObj.h"
+#include "AliITSRecPoint.h"
+#include "AliESDEvent.h"
+#include "AliESDtrack.h"
 #include "AliITSRecPoint.h"
-#include "AliTPCtrack.h"
-#include "AliITSclusterV2.h"
+#include "AliITSReconstructor.h"
 #include "AliITStrackerV2.h"
 
-//#define DEBUG
+ClassImp(AliITStrackerV2)
+
+AliITStrackerV2::AliITSlayer AliITStrackerV2::fgLayers[AliITSgeomTGeo::kNLayers]; //ITS layers
+
+AliITStrackerV2::AliITStrackerV2(): 
+  AliTracker(), 
+  fI(AliITSgeomTGeo::GetNLayers()),
+  fBestTrack(),
+  fTrackToFollow(),
+  fPass(0),
+  fLastLayerToTrackTo(AliITSRecoParam::GetLastLayerToTrackTo())
+{
+  //--------------------------------------------------------------------
+  //This is the AliITStrackerV2 default constructor
+  //--------------------------------------------------------------------
+
+  for (Int_t i=1; i<AliITSgeomTGeo::GetNLayers()+1; i++) new(fgLayers+i-1) AliITSlayer();
 
-#ifdef DEBUG
-Int_t LAB=236;
-#endif
+  fConstraint[0]=1; fConstraint[1]=0;
 
-extern TRandom *gRandom;
+  Double_t xyz[]={AliITSReconstructor::GetRecoParam()->GetXVdef(),
+		  AliITSReconstructor::GetRecoParam()->GetYVdef(),
+		  AliITSReconstructor::GetRecoParam()->GetZVdef()}; 
+  Double_t ers[]={AliITSReconstructor::GetRecoParam()->GetSigmaXVdef(),
+		  AliITSReconstructor::GetRecoParam()->GetSigmaYVdef(),
+		  AliITSReconstructor::GetRecoParam()->GetSigmaZVdef()}; 
+  SetVertex(xyz,ers);
 
-AliITStrackerV2::AliITSlayer AliITStrackerV2::fLayers[kMaxLayer]; // ITS layers
+  for (Int_t i=0; i<AliITSgeomTGeo::GetNLayers(); i++) fLayersNotToSkip[i]=AliITSRecoParam::GetLayersNotToSkip(i);
 
-AliITStrackerV2::
-AliITStrackerV2(const AliITSgeom *geom, Int_t eventn) throw (const Char_t *) {
+}
+
+AliITStrackerV2::AliITStrackerV2(const AliITStrackerV2 &t): 
+  AliTracker(t), 
+  fI(t.fI),
+  fBestTrack(t.fBestTrack),
+  fTrackToFollow(t.fTrackToFollow),
+  fPass(t.fPass),
+  fLastLayerToTrackTo(t.fLastLayerToTrackTo)
+{
   //--------------------------------------------------------------------
-  //This is the AliITStracker constructor
-  //It also reads clusters from a root file
+  //This is the AliITStrackerV2 copy constructor
   //--------------------------------------------------------------------
- 
-  fEventN = eventn;  //MI change add event number  - used to generate identifier 
-  fYV=fZV=0.;
 
-  AliITSgeom *g=(AliITSgeom*)geom;
+  //for (Int_t i=1; i<AliITSgeomTGeo::GetNLayers()+1; i++) new(fgLayers+i-1) AliITSlayer();
 
-  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);
+  fConstraint[0]=t.fConstraint[0]; fConstraint[1]=t.fConstraint[1];
 
-    g->GetTrans(i,1,1,x,y,z); 
-    Double_t r=TMath::Sqrt(x*x + y*y);
+  Double_t xyz[]={AliITSReconstructor::GetRecoParam()->GetXVdef(),
+		  AliITSReconstructor::GetRecoParam()->GetYVdef(),
+		  AliITSReconstructor::GetRecoParam()->GetZVdef()}; 
+  Double_t ers[]={AliITSReconstructor::GetRecoParam()->GetSigmaXVdef(),
+		  AliITSReconstructor::GetRecoParam()->GetSigmaYVdef(),
+		  AliITSReconstructor::GetRecoParam()->GetSigmaZVdef()}; 
+  xyz[0]=t.GetX(); xyz[1]=t.GetY(); xyz[2]=t.GetZ(); 
+  ers[0]=t.GetSigmaX(); ers[1]=t.GetSigmaY(); ers[2]=t.GetSigmaZ(); 
+  SetVertex(xyz,ers);
+
+  for (Int_t i=0; i<AliITSgeomTGeo::GetNLayers(); i++) fLayersNotToSkip[i]=t.fLayersNotToSkip[i];
+
+}
+
+AliITStrackerV2::AliITStrackerV2(const Char_t *geom) : 
+  AliTracker(), 
+  fI(AliITSgeomTGeo::GetNLayers()),
+  fBestTrack(),
+  fTrackToFollow(),
+  fPass(0),
+  fLastLayerToTrackTo(AliITSRecoParam::GetLastLayerToTrackTo())
+{
+  //--------------------------------------------------------------------
+  //This is the AliITStrackerV2 constructor
+  //--------------------------------------------------------------------
+  if (geom) {
+    AliWarning("\"geom\" is actually a dummy argument !");
+  }
+
+  for (Int_t i=1; i<AliITSgeomTGeo::GetNLayers()+1; i++) {
+    Int_t nlad=AliITSgeomTGeo::GetNLadders(i);
+    Int_t ndet=AliITSgeomTGeo::GetNDetectors(i);
+
+    Double_t xyz[3], &x=xyz[0], &y=xyz[1], &z=xyz[2];
+    AliITSgeomTGeo::GetOrigTranslation(i,1,1,xyz); 
     Double_t poff=TMath::ATan2(y,x);
     Double_t zoff=z;
+    Double_t r=TMath::Sqrt(x*x + y*y);
 
-    g->GetTrans(i,1,2,x,y,z);
+    AliITSgeomTGeo::GetOrigTranslation(i,1,2,xyz);
     r += TMath::Sqrt(x*x + y*y);
-    g->GetTrans(i,2,1,x,y,z);
+    AliITSgeomTGeo::GetOrigTranslation(i,2,1,xyz);
     r += TMath::Sqrt(x*x + y*y);
-    g->GetTrans(i,2,2,x,y,z);
+    AliITSgeomTGeo::GetOrigTranslation(i,2,2,xyz);
     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(); 
-        AliITSdetector &det=fLayers[i-1].GetDetector((j-1)*ndet + k-1); 
-
-if (phi<0) phi += 2*TMath::Pi();
-
+        TGeoHMatrix m; AliITSgeomTGeo::GetOrigMatrix(i,j,k,m);
+        const TGeoHMatrix *tm=AliITSgeomTGeo::GetTracking2LocalMatrix(i,j,k);
+        m.Multiply(tm);
+        Double_t txyz[3]={0.}; 
+	xyz[0]=0.; xyz[1]=0.; xyz[2]=0.;
+        m.LocalToMaster(txyz,xyz);
+        r=TMath::Sqrt(xyz[0]*xyz[0] + xyz[1]*xyz[1]);
+        Double_t phi=TMath::ATan2(xyz[1],xyz[0]);
+
+        if (phi<0) phi+=TMath::TwoPi();
+        else if (phi>=TMath::TwoPi()) phi-=TMath::TwoPi();
+
+        AliITSdetector &det=fgLayers[i-1].GetDetector((j-1)*ndet + k-1); 
         new(&det) AliITSdetector(r,phi); 
       } 
     }  
 
   }
 
-  try {
-     //Read clusters
-    //MI change 
-    char   cname[100]; 
-    sprintf(cname,"TreeC_ITS_%d",eventn);
-     TTree *cTree=(TTree*)gDirectory->Get(cname);
-    //     TTree *cTree=(TTree*)gDirectory->Get("cTree");
-
-     if (!cTree) throw 
-        ("AliITStrackerV2::AliITStrackerV2 can't get cTree !\n");
-
-     TBranch *branch=cTree->GetBranch("Clusters");
-     if (!branch) throw 
-        ("AliITStrackerV2::AliITStrackerV2 can't get Clusters branch !\n");
-
-     TClonesArray dummy("AliITSclusterV2",10000), *clusters=&dummy;
-     branch->SetAddress(&clusters);
-
-     Int_t nentr=(Int_t)cTree->GetEntries();
-     for (i=0; i<nentr; i++) {
-       if (!cTree->GetEvent(i)) continue;
-       //Int_t lay,lad,det; g->GetModuleId(i-1,lay,lad,det);
-       Int_t lay,lad,det; g->GetModuleId(i,lay,lad,det);
-       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
-
-         AliITSdetector &det=fLayers[lay-1].GetDetector(c->GetDetectorIndex());
-         Double_t r=det.GetR(); r=TMath::Sqrt(r*r + c->GetY()*c->GetY());
-         if (r > TMath::Abs(c->GetZ())-0.5)
-            fLayers[lay-1].InsertCluster(new AliITSclusterV2(*c));
-       }
-       clusters->Delete();
-     }
-  }
-  catch (const Char_t *msg) {
-    cerr<<msg<<endl;
-    throw;
-  }
+  fConstraint[0]=1; fConstraint[1]=0;
 
-  fI=kMaxLayer;
-}
+  Double_t xyz[]={AliITSReconstructor::GetRecoParam()->GetXVdef(),
+		  AliITSReconstructor::GetRecoParam()->GetYVdef(),
+		  AliITSReconstructor::GetRecoParam()->GetZVdef()}; 
+  Double_t ers[]={AliITSReconstructor::GetRecoParam()->GetSigmaXVdef(),
+		  AliITSReconstructor::GetRecoParam()->GetSigmaYVdef(),
+		  AliITSReconstructor::GetRecoParam()->GetSigmaZVdef()}; 
+  SetVertex(xyz,ers);
+
+  for (Int_t i=0; i<AliITSgeomTGeo::GetNLayers(); i++) fLayersNotToSkip[i]=AliITSRecoParam::GetLayersNotToSkip(i);
 
-#ifdef DEBUG
-static Int_t lbl;
-#endif
+}
 
-Int_t AliITStrackerV2::Clusters2Tracks(const TFile *inp, TFile *out) {
+void AliITStrackerV2::SetLayersNotToSkip(Int_t *l) {
   //--------------------------------------------------------------------
-  //This functions reconstructs ITS tracks
+  //This function set masks of the layers which must be not skipped
   //--------------------------------------------------------------------
-  TFile *in=(TFile*)inp;
-  TDirectory *savedir=gDirectory; 
+  for (Int_t i=0; i<AliITSgeomTGeo::GetNLayers(); i++) fLayersNotToSkip[i]=l[i];
+}
 
-  if (!in->IsOpen()) {
-     cerr<<"AliITStrackerV2::Clusters2Tracks(): ";
-     cerr<<"file with TPC tracks is not open !\n";
-     return 1;
+Int_t AliITStrackerV2::LoadClusters(TTree *cTree) {
+  //--------------------------------------------------------------------
+  //This function loads ITS clusters
+  //--------------------------------------------------------------------
+  TBranch *branch=cTree->GetBranch("ITSRecPoints");
+  if (!branch) { 
+    Error("LoadClusters"," can't get the branch !\n");
+    return 1;
   }
 
-  if (!out->IsOpen()) {
-     cerr<<"AliITStrackerV2::Clusters2Tracks(): ";
-     cerr<<"file for ITS tracks is not open !\n";
-     return 2;
-  }
+  TClonesArray dummy("AliITSRecPoint",10000), *clusters=&dummy;
+  branch->SetAddress(&clusters);
 
-  in->cd(); 
-  //
-  char   tname[100];
-  sprintf(tname,"TreeT_TPC_%d",fEventN);
-  TTree *tpcTree=(TTree*)in->Get(tname);
-  //TTree *tpcTree=(TTree*)in->Get("TPCf");
-
-  if (!tpcTree) {
-     cerr<<"AliITStrackerV2::Clusters2Tracks() ";
-     cerr<<"can't get a tree with TPC tracks !\n";
-     return 3;
-  }
+  Int_t j=0;
+  for (Int_t i=0; i<AliITSgeomTGeo::GetNLayers(); i++) {
+    Int_t ndet=fgLayers[i].GetNdetectors();
+    Int_t jmax = j + fgLayers[i].GetNladders()*ndet;
 
-  AliTPCtrack *itrack=new AliTPCtrack; 
-  tpcTree->SetBranchAddress("tracks",&itrack);
+    Double_t r=fgLayers[i].GetR();
+    Double_t circ=TMath::TwoPi()*r;
 
-  out->cd();
-  TTree itsTree("ITSf","Tree with ITS tracks");
-  AliITStrackV2 *otrack=&fBestTrack;
-  itsTree.Branch("tracks","AliITStrackV2",&otrack,32000,0);
+    for (; j<jmax; j++) {           
+      if (!cTree->GetEvent(j)) continue;
+      Int_t ncl=clusters->GetEntriesFast();
+ 
+      while (ncl--) {
+        AliITSRecPoint *c=(AliITSRecPoint*)clusters->UncheckedAt(ncl);
 
-  Int_t ntrk=0;
+	if (!c->Misalign()) AliWarning("Can't misalign this cluster !");
 
-  Int_t nentr=(Int_t)tpcTree->GetEntries();
-  for (Int_t i=0; i<nentr; i++) {
+        Int_t idx=c->GetDetectorIndex();
+        AliITSdetector &det=fgLayers[i].GetDetector(idx);
+   
+        Double_t y=r*det.GetPhi()+c->GetY();
+        if (y>circ) y-=circ; else if (y<0) y+=circ;
+        c->SetPhiR(y);
 
-    if (!tpcTree->GetEvent(i)) continue;
-    Int_t tpcLabel=itrack->GetLabel(); //save the TPC track label
+        fgLayers[i].InsertCluster(new AliITSRecPoint(*c));
+      }
+      clusters->Delete();
+    }
+    fgLayers[i].ResetRoad(); //road defined by the cluster density
+  }
 
-#ifdef DEBUG
-lbl=tpcLabel;
-if (TMath::Abs(tpcLabel)!=LAB) continue;
-cout<<tpcLabel<<" *****************\n";
-#endif
+  return 0;
+}
 
-    try {
-      ResetTrackToFollow(AliITStrackV2(*itrack));
-    } catch (const Char_t *msg) {
-      cerr<<msg<<endl;
-      continue;
-    }
-    ResetBestTrack();
-
-    fYV=gRandom->Gaus(0.,kSigmaYV); fZV=gRandom->Gaus(0.,kSigmaZV);
-
-    Double_t r2=fTrackToFollow.GetX()*fTrackToFollow.GetX();
-    Double_t x0=0.082/21.82*2.33*(45*45+40*40)/r2+2.000/41.28*0.03*75*75/r2;
-    fTrackToFollow.Improve(x0,fYV,fZV);
-
-    Double_t xk=80.;
-    fTrackToFollow.PropagateTo(xk,0.,0.); //Ne if it's still there
-
-    xk-=0.005;
-    fTrackToFollow.PropagateTo(xk, 0.005/44.77*1.71, 0.005*1.71); //Tedlar
-    xk-=0.02;
-    fTrackToFollow.PropagateTo(xk, 0.02/44.86*1.45, 0.02*1.45);   //Kevlar
-       xk-=2.0;
-       fTrackToFollow.PropagateTo(xk, 2.0/41.28*0.029, 2.0*0.029);//Nomex
-    xk-=0.02;
-    fTrackToFollow.PropagateTo(xk, 0.02/44.86*1.45, 0.02*1.45);   //Kevlar
-    xk-=0.005;
-    fTrackToFollow.PropagateTo(xk, 0.005/44.77*1.71, 0.005*1.71); //Tedlar
-
-    xk=61.;
-    fTrackToFollow.PropagateTo(xk,0.,0.); //C02
-
-    xk -=0.005;
-    fTrackToFollow.PropagateTo(xk, 0.005/24.01*2.7, 0.005*2.7);    //Al    
-    xk -=0.005;
-    fTrackToFollow.PropagateTo(xk, 0.005/44.77*1.71, 0.005*1.71);  //Tedlar
-    xk -=0.02;
-    fTrackToFollow.PropagateTo(xk, 0.02/44.86*1.45, 0.02*1.45);    //Kevlar
-       xk -=0.5;
-       fTrackToFollow.PropagateTo(xk, 0.5/41.28*.029, 0.5*0.029);  //Nomex    
-    xk -=0.02;
-    fTrackToFollow.PropagateTo(xk, 0.02/44.86*1.45, 0.02*1.45);    //Kevlar
-    xk -=0.005;
-    fTrackToFollow.PropagateTo(xk, 0.005/44.77*1.71, 0.005*1.71);  //Tedlar
-    xk -=0.005;
-    fTrackToFollow.PropagateTo(xk, 0.005/24.01*2.7, 0.005*2.7);    //Al    
-
-
-    for (FollowProlongation(); fI<kMaxLayer; fI++) {
-       while (TakeNextProlongation()) FollowProlongation();
+void AliITStrackerV2::UnloadClusters() {
+  //--------------------------------------------------------------------
+  //This function unloads ITS clusters
+  //--------------------------------------------------------------------
+  for (Int_t i=0; i<AliITSgeomTGeo::GetNLayers(); i++) fgLayers[i].ResetClusters();
+}
+
+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(AliESDEvent *event) {
+  //--------------------------------------------------------------------
+  // This functions reconstructs ITS tracks
+  // The clusters must be already loaded !
+  //--------------------------------------------------------------------
+  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(GetX(),GetY()))>4) {
+	delete t;
+	continue;
+      }
+
+      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 */
+
+  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
+
+       ResetTrackToFollow(*t);
+       ResetBestTrack();
+
+       for (FollowProlongation(); fI<AliITSgeomTGeo::GetNLayers(); fI++) {
+          while (TakeNextProlongation()) FollowProlongation();
+       }
+
+       if (fBestTrack.GetNumberOfClusters() == 0) continue;
 
-#ifdef DEBUG
-cout<<fBestTrack.GetNumberOfClusters()<<" number of clusters\n\n";
-#endif
+       if (fConstraint[fPass]) {
+          ResetTrackToFollow(*t);
+          if (!RefitAt(3.7, &fTrackToFollow, &fBestTrack)) continue;
+          ResetBestTrack();
+       }
 
-    if (fBestTrack.GetNumberOfClusters() >= kMaxLayer-kLayersToSkip) {
-       cerr << ++ntrk << "                \r";
        fBestTrack.SetLabel(tpcLabel);
+       fBestTrack.CookdEdx();
+       CookLabel(&fBestTrack,0.); //For comparison only
+       fBestTrack.UpdateESDtrack(AliESDtrack::kITSin);
        UseClusters(&fBestTrack);
-       itsTree.Fill();
-    }
-
+       delete itsTracks.RemoveAt(i);
+       ntrk++;
+     }
   }
-  sprintf(tname,"TreeT_ITS_%d",fEventN);
-  itsTree.Write(tname);
-  savedir->cd();
-  cerr<<"Number of TPC tracks: "<<nentr<<endl;
-  cerr<<"Number of prolonged tracks: "<<ntrk<<endl;
 
-  delete itrack;
+  itsTracks.Delete();
+
+  Info("Clusters2Tracks","Number of prolonged tracks: %d\n",ntrk);
 
   return 0;
 }
 
-Int_t AliITStrackerV2::PropagateBack(const TFile *inp, TFile *out) {
+Int_t AliITStrackerV2::PropagateBack(AliESDEvent *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; 
+  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();
-  TTree *itsTree=(TTree*)in->Get("ITSf");
-  if (!itsTree) {
-     cerr<<"AliITStrackerV2::PropagateBack() ";
-     cerr<<"can't get a tree with ITS tracks !\n";
-     return 3;
+     // 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(event->GetVertex())) {
+          fTrackToFollow.StartTimeIntegral();
+       }
+       fTrackToFollow.PropagateTo(3.,-0.0028,65.19);
+     }
+
+     fTrackToFollow.ResetCovariance(10.); 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();
-  TTree backTree("ITSb","Tree with back propagated ITS tracks");
-  AliTPCtrack *otrack=0;
-  backTree.Branch("tracks","AliTPCtrack",&otrack,32000,0);
+  Info("PropagateBack","Number of back propagated ITS tracks: %d\n",ntrk);
 
-  Int_t ntrk=0;
+  return 0;
+}
 
-  Int_t nentr=(Int_t)itsTree->GetEntries();
+Int_t AliITStrackerV2::RefitInward(AliESDEvent *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 ntrk=0;
   for (Int_t i=0; i<nentr; i++) {
-    itsTree->GetEvent(i);
-    ResetTrackToFollow(*itrack);
-    fTrackToFollow.ResetCovariance(); fTrackToFollow.ResetClusters();
-    Int_t itsLabel=fTrackToFollow.GetLabel(); //save the ITS track label
+    AliESDtrack *esd=event->GetTrack(i);
 
-#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 ds=0.034; if (fI==4) ds=0.039;
-            Double_t dx0r=ds/21.82*2.33, dr=ds*2.33;
-            if (!fTrackToFollow.PropagateTo(rs,1*dx0r,dr)) throw "";
-         }
-
-         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);
-         Double_t d=layer.GetThickness(phi,z);
-         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,d/21.82*2.33,d*2.33)) throw "";
-
-         const AliITSclusterV2 *cl=0;
-         Int_t index=0;
-         Double_t maxchi2=kMaxChi2;
-
-         if (l==fI) {
-           if (idet != c->GetDetectorIndex()) {
-             idet=c->GetDetectorIndex();
-             const AliITSdetector &det=layer.GetDetector(idet);
-             r=det.GetR(); phi=det.GetPhi();
-             if (!fTrackToFollow.Propagate(phi,r,0.,0.)) throw "";
-           }
-           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 (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) {
-              if (idet != cc->GetDetectorIndex()) continue;
-              Double_t chi2=fTrackToFollow.GetPredictedChi2(cc);
-              if (chi2<maxchi2) {
-                 cl=cc; index=(fI<<28)+ci; maxchi2=chi2;
-              }
-           }
-         }
-
-         if (cl) {
-            if (!fTrackToFollow.Update(cl,maxchi2,index)) 
-              cerr<<"AliITStrackerV2::PropagateBack: filtering failed !\n";
-              continue;
-         }
-       }
+        t=new AliITStrackV2(*esd);
+    } catch (const Char_t *msg) {
+        Warning("RefitInward",msg);
+        delete t;
+        continue;
+    }
 
-       Double_t xk=61.;
-       fTrackToFollow.PropagateTo(xk,0.,0.); //Air
-
-       xk +=0.005;
-       fTrackToFollow.PropagateTo(xk, 0.005/24.01*2.7, 0.005*2.7);    //Al    
-       xk +=0.005;
-       fTrackToFollow.PropagateTo(xk, 0.005/44.77*1.71, 0.005*1.71);  //Tedlar
-       xk +=0.02;
-       fTrackToFollow.PropagateTo(xk, 0.02/44.86*1.45, 0.02*1.45);    //Kevlar
-          xk +=0.5;
-          fTrackToFollow.PropagateTo(xk, 0.5/41.28*.029, 0.5*0.029);  //Nomex 
-       xk +=0.02;
-       fTrackToFollow.PropagateTo(xk, 0.02/44.86*1.45, 0.02*1.45);    //Kevlar
-       xk +=0.005;
-       fTrackToFollow.PropagateTo(xk, 0.005/44.77*1.71, 0.005*1.71);  //Tedlar
-       xk +=0.005;
-       fTrackToFollow.PropagateTo(xk, 0.005/24.01*2.7, 0.005*2.7);    //Al    
-
-       xk=80.;
-       fTrackToFollow.PropagateTo(xk,0.,0.); //CO2
-
-       xk+=0.005;
-       fTrackToFollow.PropagateTo(xk, 0.005/44.77*1.71, 0.005*1.71); //Tedlar
-       xk+=0.02;
-       fTrackToFollow.PropagateTo(xk, 0.02/44.86*1.45, 0.02*1.45);   //Kevlar
-          xk+=2.0;
-          fTrackToFollow.PropagateTo(xk, 2.0/41.28*0.029, 2.0*0.029);//Nomex
-       xk+=0.02;
-       fTrackToFollow.PropagateTo(xk, 0.02/44.86*1.45, 0.02*1.45);   //Kevlar
-       xk+=0.005;
-       fTrackToFollow.PropagateTo(xk, 0.005/44.77*1.71, 0.005*1.71); //Tedlar
-
-       fTrackToFollow.SetLabel(itsLabel);
-       otrack=new AliTPCtrack(fTrackToFollow,fTrackToFollow.GetAlpha()); 
-       backTree.Fill(); delete otrack;
-       UseClusters(&fTrackToFollow);
-       cerr << ++ntrk << "                \r";
+    if (CorrectForDeadZoneMaterial(t)!=0) {
+       Warning("RefitInward",
+               "failed to correct for the material in the dead zone !\n");
+       delete t;
+       continue;
     }
-    catch (const Char_t *msg) {
-       cerr<<msg<<endl;
+
+    ResetTrackToFollow(*t);
+    fTrackToFollow.ResetClusters();
+
+    //Refitting...
+    if (RefitAt(3.7, &fTrackToFollow, t, kTRUE)) {
+       fTrackToFollow.SetLabel(t->GetLabel());
+       fTrackToFollow.CookdEdx();
+       CookLabel(&fTrackToFollow,0.); //For comparison only
+
+       if (fTrackToFollow.PropagateTo(3.,0.0028,65.19)) {//The beam pipe 
+	 fTrackToFollow.UpdateESDtrack(AliESDtrack::kITSrefit);
+         AliESDtrack  *esdTrack =fTrackToFollow.GetESDtrack();
+         Double_t r[3]={0.,0.,0.};
+         Double_t maxD=3.;
+	 esdTrack->RelateToVertex(event->GetVertex(),GetBz(r),maxD);
+         ntrk++;
+       }
     }
+    delete t;
   }
 
-  backTree.Write();
-  savedir->cd();
-  cerr<<"Number of ITS tracks: "<<nentr<<endl;
-  cerr<<"Number of back propagated ITS tracks: "<<ntrk<<endl;
-
-  delete itrack;
+  Info("RefitInward","Number of refitted tracks: %d\n",ntrk);
 
   return 0;
 }
@@ -463,7 +472,7 @@ 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);
 }
 
 
@@ -471,71 +480,83 @@ void AliITStrackerV2::FollowProlongation() {
   //--------------------------------------------------------------------
   //This function finds a track prolongation 
   //--------------------------------------------------------------------
-  Int_t tryAgain=kLayersToSkip;
+  while (fI>fLastLayerToTrackTo) {
+    Int_t i=fI-1;
 
-  while (fI) {
-    fI--;
-#ifdef DEBUG
-cout<<fI<<' ';
-#endif
-    AliITSlayer &layer=fLayers[fI];
-    AliITStrackV2 &track=fTracks[fI];
+    AliITSlayer &layer=fgLayers[i];
+    AliITStrackV2 &track=fTracks[i];
 
     Double_t r=layer.GetR();
-    if (fI==3 || fI==1) {
-      Double_t rs=0.5*(fLayers[fI+1].GetR() + r);
-      Double_t ds=0.034; if (fI==3) ds=0.039;
-      Double_t dx0r=ds/21.82*2.33, dr=ds*2.33;
-      fTrackToFollow.Propagate(fTrackToFollow.GetAlpha(),rs,1*dx0r,dr);
+
+    if (i==3 || i==1) {
+       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)) {
+	 //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;
+    Double_t phi,z;  
+    if (!fTrackToFollow.GetPhiZat(r,phi,z)) {
+      //Warning("FollowProlongation","failed to estimate track !\n");
+      return;
     }
-    Double_t phi=TMath::ATan2(y,x);
-    Double_t d=layer.GetThickness(phi,z);
+
     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(),1*d/21.82*2.33,d*2.33)) {
-      cerr<<"AliITStrackerV2::FollowProlongation: propagation failed !\n";
-      break;
+    if (!fTrackToFollow.Propagate(phi,det.GetR())) {
+      //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[fI]);
+    Double_t dz=7*TMath::Sqrt(track.GetSigmaZ2() + AliITSReconstructor::GetRecoParam()->GetSigmaZ2(i));
+    Double_t dy=7*TMath::Sqrt(track.GetSigmaY2() + AliITSReconstructor::GetRecoParam()->GetSigmaY2(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() + AliITSReconstructor::GetRecoParam()->GetSigmaZ2(i));
     if (dz < 0.5*TMath::Abs(track.GetTgl())) dz=0.5*TMath::Abs(track.GetTgl());
-    if (dz > kMaxRoad/4) {
-      //cerr<<"AliITStrackerV2::FollowProlongation: too broad road in Z !\n";
-      break;
+    if (dz > AliITSReconstructor::GetRecoParam()->GetMaxRoad()) {
+      //Warning("FollowProlongation","too broad road in Z !\n");
+      return;
     }
-    Double_t dy=4*TMath::Sqrt(track.GetSigmaY2() + kSigmaY2[fI]);
+
+    if (TMath::Abs(fTrackToFollow.GetZ()-GetZ()) > r+dz) return;
+
+    //Double_t dy=4*TMath::Sqrt(track.GetSigmaY2() + AliITSReconstructor::GetRecoParam()->GetSigmaY2(i));
     if (dy < 0.5*TMath::Abs(track.GetSnp())) dy=0.5*TMath::Abs(track.GetSnp());
-    if (dy > kMaxRoad/4) {
-      //cerr<<"AliITStrackerV2::FollowProlongation: too broad road in Y !\n";
-      break;
+    if (dy > AliITSReconstructor::GetRecoParam()->GetMaxRoad()) {
+      //Warning("FollowProlongation","too broad road in Y !\n");
+      return;
     }
 
-    Double_t zmin=track.GetZ() - dz;
+    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);
+    if (layer.SelectClusters(zmin,zmax,ymin,ymax)==0) 
+       if (fLayersNotToSkip[fI]) return;  
 
-    //take another prolongation
-    if (!TakeNextProlongation()) if (!tryAgain--) break;
-    tryAgain=kLayersToSkip;
+    if (!TakeNextProlongation()) 
+       if (fLayersNotToSkip[fI]) return;
 
   } 
 
@@ -545,112 +566,130 @@ cout<<fI<<' ';
   if (ncl)
   if (ncl >= nclb) {
      Double_t chi2=fTrackToFollow.GetChi2();
-     if (chi2/ncl < kChi2PerCluster) {        
+     if (chi2/ncl < AliITSReconstructor::GetRecoParam()->GetChi2PerCluster()) {        
         if (ncl > nclb || chi2 < fBestTrack.GetChi2()) {
            ResetBestTrack();
         }
      }
   }
 
-  if (fI) fI++;
 }
 
-
 Int_t AliITStrackerV2::TakeNextProlongation() {
   //--------------------------------------------------------------------
-  //This function takes another track prolongation 
+  // This function takes another track prolongation 
+  //
+  //  dEdx analysis by: Boris Batyunya, JINR, Boris.Batiounia@cern.ch 
   //--------------------------------------------------------------------
-  //Double_t m[20];
-  Double_t d=GetEffectiveThickness(0,0); //Think of this !!!!
-
-  AliITSlayer &layer=fLayers[fI];
-  AliITStrackV2 &t=fTracks[fI];
-
-  Double_t dz=4*TMath::Sqrt(t.GetSigmaZ2() + kSigmaZ2[fI]);
-  Double_t dy=4*TMath::Sqrt(t.GetSigmaY2() + kSigmaY2[fI]);
+  AliITSlayer &layer=fgLayers[fI];
+  ResetTrackToFollow(fTracks[fI]);
+
+  Double_t dz=7*TMath::Sqrt(fTrackToFollow.GetSigmaZ2() + AliITSReconstructor::GetRecoParam()->GetSigmaZ2(fI));
+  Double_t dy=7*TMath::Sqrt(fTrackToFollow.GetSigmaY2() + AliITSReconstructor::GetRecoParam()->GetSigmaY2(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.;
+  const AliITSRecPoint *c=0; Int_t ci=-1;
+  const AliITSRecPoint *cc=0; Int_t cci=-1;
+  Double_t chi2=AliITSReconstructor::GetRecoParam()->GetMaxChi2();
   while ((c=layer.GetNextCluster(ci))!=0) {
-
-#ifdef DEBUG
-//if (fI==0)
-//if (c->GetLabel(0)!=TMath::Abs(lbl)) continue; 
-#endif
-
     Int_t idet=c->GetDetectorIndex();
 
-    if (t.GetDetectorIndex()!=idet) {
+    if (fTrackToFollow.GetDetectorIndex()!=idet) {
        const AliITSdetector &det=layer.GetDetector(idet);
-       if (!t.Propagate(det.GetPhi(),det.GetR(),0.,0.)) {
-         cerr<<"AliITStrackerV2::TakeNextProlongation: propagation failed !\n";
+       ResetTrackToFollow(fTracks[fI]);
+       if (!fTrackToFollow.Propagate(det.GetPhi(),det.GetR())) {
+         //Warning("TakeNextProlongation","propagation failed !\n");
          continue;
        }
-       t.SetDetectorIndex(idet);
-
-#ifdef DEBUG
-cout<<fI<<" change detector !\n";
-#endif
-
+       fTrackToFollow.SetDetectorIndex(idet);
+       if (TMath::Abs(fTrackToFollow.GetZ()-GetZ())>layer.GetR()+dz) continue;
     }
 
-    if (TMath::Abs(t.GetZ() - c->GetZ()) > dz) continue;
-    if (TMath::Abs(t.GetY() - c->GetY()) > dy) continue;
-
-    //m[0]=fYV; m[1]=fZV;
-    //chi2=t.GetPredictedChi2(c,m,d/21.82*2.33);
-    chi2=t.GetPredictedChi2(c);
+    if (TMath::Abs(fTrackToFollow.GetZ() - c->GetZ()) > dz) continue;
+    if (TMath::Abs(fTrackToFollow.GetY() - c->GetY()) > dy) continue;
 
-    if (chi2<kMaxChi2) break;
+    Double_t ch2=fTrackToFollow.GetPredictedChi2(c); 
+    if (ch2 > chi2) continue;
+    chi2=ch2;
+    cc=c; cci=ci;
+    break;
   }
 
-#ifdef DEBUG
-cout<<fI<<" chi2="<<chi2<<' '<<t.GetY()<<' '<<t.GetZ()<<' '<<dy<<' '<<dz<<endl;
-#endif
+  if (!cc) return 0;
 
-  if (chi2>=kMaxChi2) return 0;
-  if (!c) return 0;
+  {// Take into account the mis-alignment
+    Double_t x = fTrackToFollow.GetX() + cc->GetX();
+    if (!fTrackToFollow.PropagateTo(x,0.,0.)) return 0;
+  }
+  if (!fTrackToFollow.Update(cc,chi2,(fI<<28)+cci)) {
+     //Warning("TakeNextProlongation","filtering failed !\n");
+     return 0;
+  }
 
-  ResetTrackToFollow(t);
+  if (fTrackToFollow.GetNumberOfClusters()>1)
+    if (TMath::Abs(fTrackToFollow.GetD(GetX(),GetY()))>4) return 0;
 
-  //if (!fTrackToFollow.Update(m,chi2,(fI<<28)+ci)) {
-  if (!fTrackToFollow.Update(c,chi2,(fI<<28)+ci)) {
-     cerr<<"AliITStrackerV2::TakeNextProlongation: filtering failed !\n";
-     return 0;
+  fTrackToFollow.
+    SetSampledEdx(cc->GetQ(),fI-2); //b.b.
+
+  {
+  Double_t x0;
+ Double_t d=layer.GetThickness(fTrackToFollow.GetY(),fTrackToFollow.GetZ(),x0);
+  fTrackToFollow.CorrectForMaterial(d,x0);
   }
-  fTrackToFollow.Improve(d/21.82*2.33,fYV,fZV);
 
-#ifdef DEBUG
-cout<<"accepted lab="<<c->GetLabel(0)<<' '
-    <<fTrackToFollow.GetNumberOfClusters()<<' '
-    <<fTrackToFollow.GetY()<<' '<<fTrackToFollow.GetZ()<<endl<<endl;
-#endif
+  if (fConstraint[fPass]) {
+    Double_t d=GetEffectiveThickness(0,0); //Think of this !!!!
+    Double_t xyz[]={GetX(),GetY(),GetZ()};
+    Double_t ers[]={GetSigmaX(),GetSigmaY(),GetSigmaZ()};
+    fTrackToFollow.Improve(d,xyz,ers);
+  }
 
   return 1;
 }
 
 
-
-
-AliITStrackerV2::AliITSlayer::AliITSlayer() {
+AliITStrackerV2::AliITSlayer::AliITSlayer():
+  fR(0.),
+  fPhiOffset(0.),
+  fNladders(0),
+  fZOffset(0.),
+  fNdetectors(0),
+  fDetectors(0),
+  fNsel(0),
+  fRoad(2*fR*TMath::Sqrt(3.14/1.)) //assuming that there's only one cluster
+{
   //--------------------------------------------------------------------
   //default AliITSlayer constructor
   //--------------------------------------------------------------------
-  fN=0;
-  fDetectors=0;
+  
+  for (Int_t i=0; i<kNsector; i++) fN[i]=0;
+
 }
 
 AliITStrackerV2::AliITSlayer::
-AliITSlayer(Double_t r,Double_t p,Double_t z,Int_t nl,Int_t nd) {
+AliITSlayer(Double_t r,Double_t p,Double_t z,Int_t nl,Int_t nd): 
+  fR(r), 
+  fPhiOffset(p), 
+  fNladders(nl),
+  fZOffset(z),
+  fNdetectors(nd),
+  fDetectors(new AliITSdetector[nl*nd]),
+  fNsel(0),
+  fRoad(2*r*TMath::Sqrt(3.14/1.)) //assuming that there's only one cluster
+{
   //--------------------------------------------------------------------
   //main AliITSlayer constructor
   //--------------------------------------------------------------------
-  fR=r; fPhiOffset=p; fZOffset=z;
-  fNladders=nl; fNdetectors=nd;
-  fDetectors=new AliITSdetector[fNladders*fNdetectors];
 
-  fN=0;
-  fI=0;
+  for (Int_t i=0; i<kNsector; i++) fN[i]=0;
+
+  for (Int_t i=0; i<AliITSRecoParam::fgkMaxClusterPerLayer; i++) fClusters[i]=0;
+
 }
 
 AliITStrackerV2::AliITSlayer::~AliITSlayer() {
@@ -658,34 +697,78 @@ AliITStrackerV2::AliITSlayer::~AliITSlayer() {
   // AliITSlayer destructor
   //--------------------------------------------------------------------
   delete[] fDetectors;
-  for (Int_t i=0; i<fN; i++) delete fClusters[i];
+  ResetClusters();
 }
 
-Int_t AliITStrackerV2::AliITSlayer::InsertCluster(AliITSclusterV2 *c) {
+void AliITStrackerV2::AliITSlayer::ResetClusters() {
   //--------------------------------------------------------------------
-  //This function adds a cluster to this layer
+  // This function removes loaded clusters
   //--------------------------------------------------------------------
-  if (fN==kMaxClusterPerLayer) {
- cerr<<"AliITStrackerV2::AliITSlayer::InsertCluster(): Too many clusters !\n"; 
-   return 1;
-  }
+   for (Int_t s=0; s<kNsector; s++) {
+       Int_t &n=fN[s];
+       while (n) {
+          n--;
+          delete fClusters[s*kMaxClusterPerSector+n];
+       }
+   }
+}
 
-  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++;
+void AliITStrackerV2::AliITSlayer::ResetRoad() {
+  //--------------------------------------------------------------------
+  // This function calculates the road defined by the cluster density
+  //--------------------------------------------------------------------
+  Int_t n=0;
+  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(AliITSRecPoint *c) {
+  //--------------------------------------------------------------------
+  // This function inserts a cluster to this layer in increasing
+  // order of the cluster's fZ
+  //--------------------------------------------------------------------
+  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;
+  }
+  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(AliITSRecPoint*));
+     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; 
@@ -693,126 +776,391 @@ 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++) {
+           AliITSRecPoint *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++) {
+           AliITSRecPoint *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){
+const AliITSRecPoint *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; 
+  AliITSRecPoint *c=0;
+  ci=-1;
+  if (fNsel) {
+     fNsel--;
+     ci=fIndex[fNsel]; 
+     c=fClusters[ci];
   }
-  return cluster;
+  return c; 
 }
 
-Int_t AliITStrackerV2::AliITSlayer::
-FindDetectorIndex(Double_t phi, Double_t z) const {
+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 {
   //--------------------------------------------------------------------
   //This function finds the detector crossed by the track
   //--------------------------------------------------------------------
-  Double_t dphi=phi-fPhiOffset;
+  Double_t dphi;
+  if (fZOffset<0)            // old geometry
+    dphi = -(phi-fPhiOffset);
+  else                       // new geometry
+    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);
-
-  Double_t dz=fZOffset-z;
-  Int_t nz=Int_t(dz*(fNdetectors-1)*0.5/fZOffset+0.5);
-
   if (np>=fNladders) np-=fNladders;
   if (np<0)          np+=fNladders;
 
-#ifdef DEBUG
-cout<<np<<' '<<nz<<endl;
-#endif
+  Double_t dz=fZOffset-z;
+  Int_t nz=Int_t(dz*(fNdetectors-1)*0.5/fZOffset+0.5);
+  if (nz>=fNdetectors) return -1;
+  if (nz<0)            return -1;
 
   return np*fNdetectors + nz;
 }
 
 Double_t 
-AliITStrackerV2::AliITSlayer::GetThickness(Double_t phi, Double_t z) const {
+AliITStrackerV2::AliITSlayer::GetThickness(Double_t y,Double_t z,Double_t &x0)
+const {
   //--------------------------------------------------------------------
-  //This function returns the thickness of this layer
+  //This function returns the layer thickness at this point (units X0)
   //--------------------------------------------------------------------
-  //-pi<phi<+pi
-  if (3 <fR&&fR<8 ) return 1.1*0.096;
-  if (13<fR&&fR<26) return 1.1*0.088;
-  if (37<fR&&fR<41) return 1.1*0.085;
-  return 1.1*0.081;
-}
+  Double_t d=0.0085;
+  x0=21.82;
+
+  if (43<fR&&fR<45) { //SSD2
+     Double_t dd=0.0034;
+     d=dd;
+     if (TMath::Abs(y-0.00)>3.40) d+=dd;
+     if (TMath::Abs(y-1.90)<0.45) {d+=(0.013-0.0034);}
+     if (TMath::Abs(y+1.90)<0.45) {d+=(0.013-0.0034);}
+     for (Int_t i=0; i<12; i++) {
+       if (TMath::Abs(z-3.9*(i+0.5))<0.15) {
+          if (TMath::Abs(y-0.00)>3.40) d+=dd;
+          d+=0.0034; 
+          break;
+       }
+       if (TMath::Abs(z+3.9*(i+0.5))<0.15) {
+          if (TMath::Abs(y-0.00)>3.40) d+=dd;
+          d+=0.0034; 
+          break;
+       }         
+       if (TMath::Abs(z-3.4-3.9*i)<0.50) {d+=(0.016-0.0034); break;}
+       if (TMath::Abs(z+0.5+3.9*i)<0.50) {d+=(0.016-0.0034); break;}
+     }
+  } else 
+  if (37<fR&&fR<41) { //SSD1
+     Double_t dd=0.0034;
+     d=dd;
+     if (TMath::Abs(y-0.00)>3.40) d+=dd;
+     if (TMath::Abs(y-1.90)<0.45) {d+=(0.013-0.0034);}
+     if (TMath::Abs(y+1.90)<0.45) {d+=(0.013-0.0034);}
+     for (Int_t i=0; i<11; i++) {
+       if (TMath::Abs(z-3.9*i)<0.15) {
+          if (TMath::Abs(y-0.00)>3.40) d+=dd;
+          d+=dd; 
+          break;
+       }
+       if (TMath::Abs(z+3.9*i)<0.15) {
+          if (TMath::Abs(y-0.00)>3.40) d+=dd;
+          d+=dd; 
+          break;
+       }         
+       if (TMath::Abs(z-1.85-3.9*i)<0.50) {d+=(0.016-0.0034); break;}
+       if (TMath::Abs(z+2.05+3.9*i)<0.50) {d+=(0.016-0.0034); break;}         
+     }
+  } else
+  if (13<fR&&fR<26) { //SDD
+     Double_t dd=0.0033;
+     d=dd;
+     if (TMath::Abs(y-0.00)>3.30) d+=dd;
+
+     if (TMath::Abs(y-1.80)<0.55) {
+        d+=0.016;
+        for (Int_t j=0; j<20; j++) {
+          if (TMath::Abs(z+0.7+1.47*j)<0.12) {d+=0.08; x0=9.; break;}
+          if (TMath::Abs(z-0.7-1.47*j)<0.12) {d+=0.08; x0=9.; break;}
+        } 
+     }
+     if (TMath::Abs(y+1.80)<0.55) {
+        d+=0.016;
+        for (Int_t j=0; j<20; j++) {
+          if (TMath::Abs(z-0.7-1.47*j)<0.12) {d+=0.08; x0=9.; break;}
+          if (TMath::Abs(z+0.7+1.47*j)<0.12) {d+=0.08; x0=9.; break;}
+        } 
+     }
 
+     for (Int_t i=0; i<4; i++) {
+       if (TMath::Abs(z-7.3*i)<0.60) {
+          d+=dd;
+          if (TMath::Abs(y-0.00)>3.30) d+=dd; 
+          break;
+       }
+       if (TMath::Abs(z+7.3*i)<0.60) {
+          d+=dd; 
+          if (TMath::Abs(y-0.00)>3.30) d+=dd; 
+          break;
+       }
+     }
+  } else
+  if (6<fR&&fR<8) {   //SPD2
+     Double_t dd=0.0063; x0=21.5;
+     d=dd;
+     if (TMath::Abs(y-3.08)>0.5) d+=dd;
+     //if (TMath::Abs(y-3.08)>0.45) d+=dd;
+     if (TMath::Abs(y-3.03)<0.10) {d+=0.014;}
+  } else
+  if (3<fR&&fR<5) {   //SPD1
+     Double_t dd=0.0063; x0=21.5;
+     d=dd;
+     if (TMath::Abs(y+0.21)>0.6) d+=dd;
+     //if (TMath::Abs(y+0.21)>0.45) d+=dd;
+     if (TMath::Abs(y+0.10)<0.10) {d+=0.014;}
+  }
 
-Double_t AliITStrackerV2::GetEffectiveThickness(Double_t phi,Double_t z) const
+  return d;
+}
+
+Double_t AliITStrackerV2::GetEffectiveThickness(Double_t y,Double_t z) const
 {
   //--------------------------------------------------------------------
-  //Returns the thickness between the current layer and the vertex
+  //Returns the thickness between the current layer and the vertex (units X0)
   //--------------------------------------------------------------------
-  //-pi<phi<+pi
-  Double_t d=0.1;
+  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(phi,z)*xi*xi;
+    Double_t xi=fgLayers[i].GetR();
+    d+=fgLayers[i].GetThickness(y,z,x0)*xi*xi;
   }
 
   if (fI>1) {
-    Double_t xi=0.5*(fLayers[1].GetR()+fLayers[2].GetR());
-    d+=0.034*xi*xi;
+    Double_t xi=9.;
+    d+=0.0097*xi*xi;
   }
 
   if (fI>3) {
-    Double_t xi=0.5*(fLayers[3].GetR()+fLayers[4].GetR());
-    d+=0.039*xi*xi;
+    Double_t xi=0.5*(fgLayers[3].GetR()+fgLayers[4].GetR());
+    d+=0.0034*xi*xi;
   }
+
   return d/(xn*xn);
 }
 
-
-
-Int_t AliITStrackerV2::AliITSlayer::InRoad() const {
+Bool_t AliITStrackerV2::RefitAt(Double_t xx,AliITStrackV2 *t,
+                                const AliITStrackV2 *c, Bool_t extra) {
   //--------------------------------------------------------------------
-  // This function returns number of clusters within the "window" 
+  // This function refits the track "t" at the position "x" using
+  // the clusters from "c"
+  // If "extra"==kTRUE, 
+  //    the clusters from overlapped modules get attached to "t" 
   //--------------------------------------------------------------------
-  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();
+  Int_t index[AliITSgeomTGeo::kNLayers];
+  Int_t k;
+  for (k=0; k<AliITSgeomTGeo::GetNLayers(); 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 (xx > t->GetX()) {
+      from=0; to=AliITSgeomTGeo::GetNLayers();
+      step=+1;
+  } else {
+      from=AliITSgeomTGeo::GetNLayers()-1; to=-1;
+      step=-1;
+  }
+
+  for (Int_t i=from; i != to; i += step) {
+     AliITSlayer &layer=fgLayers[i];
+     Double_t r=layer.GetR();
+ 
+     {
+     Double_t hI=i-0.5*step; 
+     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 (TMath::Abs(hI-1.5)<0.01) {rs=9.; d=0.0097; x0=42;}
+        if (!t->PropagateTo(rs,-step*d,x0)) {
+          return kFALSE;
+        }
+     }
+     }
 
-    if (y>2.*fR*TMath::Pi()) y -= 2*fR*TMath::Pi();
-    if (y>1.*fR*TMath::Pi() && fYmax<y) y -= 2*fR*TMath::Pi();
+     // 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 phi,z;
+     if (!t->GetPhiZat(r,phi,z)) { 
+       return kFALSE;
+     }
+
+     Int_t idet=layer.FindDetectorIndex(phi,z);
+     if (idet<0) { 
+       return kFALSE;
+     }
+     const AliITSdetector &det=layer.GetDetector(idet);
+     phi=det.GetPhi();
+     if (!t->Propagate(phi,det.GetR())) {
+       return kFALSE;
+     }
+     t->SetDetectorIndex(idet);
+
+     const AliITSRecPoint *cl=0;
+     Double_t maxchi2=AliITSReconstructor::GetRecoParam()->GetMaxChi2();
+
+     Int_t idx=index[i];
+     if (idx>=0) {
+        const AliITSRecPoint *ccc=(AliITSRecPoint *)GetCluster(idx); 
+        if (idet != ccc->GetDetectorIndex()) {
+           idet=ccc->GetDetectorIndex();
+           const AliITSdetector &det2=layer.GetDetector(idet);
+           if (!t->Propagate(det2.GetPhi(),det2.GetR())) {
+             return kFALSE;
+           }
+           t->SetDetectorIndex(idet);
+        }
+        Double_t chi2=t->GetPredictedChi2(ccc);
+        if (chi2<maxchi2) { 
+	  cl=ccc; 
+	  maxchi2=chi2; 
+	} else {
+	  return kFALSE;
+	}
+     }
+ 
+     if (cl) {
+       // Take into account the mis-alignment
+       Double_t x=t->GetX()+cl->GetX();
+       if (!t->PropagateTo(x,0.,0.)) return kFALSE;
+       if (!t->Update(cl,maxchi2,idx)) {
+          return kFALSE;
+       }
+       t->SetSampledEdx(cl->GetQ(),i-2);
+     }
+
+     {
+     Double_t x0;
+     Double_t d=layer.GetThickness(t->GetY(),t->GetZ(),x0);
+     t->CorrectForMaterial(-step*d,x0);
+     }
+                 
+     if (extra) { //search for extra clusters
+        AliITStrackV2 tmp(*t);
+        Double_t dz=4*TMath::Sqrt(tmp.GetSigmaZ2()+AliITSReconstructor::GetRecoParam()->GetSigmaZ2(i));
+        if (dz < 0.5*TMath::Abs(tmp.GetTgl())) dz=0.5*TMath::Abs(tmp.GetTgl());
+        Double_t dy=4*TMath::Sqrt(t->GetSigmaY2()+AliITSReconstructor::GetRecoParam()->GetSigmaY2(i));
+        if (dy < 0.5*TMath::Abs(tmp.GetSnp())) dy=0.5*TMath::Abs(tmp.GetSnp());
+        Double_t zmin=t->GetZ() - dz;
+        Double_t zmax=t->GetZ() + dz;
+        Double_t ymin=t->GetY() + phi*r - dy;
+        Double_t ymax=t->GetY() + phi*r + dy;
+        layer.SelectClusters(zmin,zmax,ymin,ymax);
+
+        const AliITSRecPoint *cx=0; Int_t ci=-1,cci=-1;
+        maxchi2=1000.*AliITSReconstructor::GetRecoParam()->GetMaxChi2();
+	Double_t tolerance=0.1;
+        while ((cx=layer.GetNextCluster(ci))!=0) {
+           if (idet == cx->GetDetectorIndex()) continue;
+
+	   const AliITSdetector &detx=layer.GetDetector(cx->GetDetectorIndex());
+
+	   if (!tmp.Propagate(detx.GetPhi(),detx.GetR())) continue;
+           
+	   if (TMath::Abs(tmp.GetZ() - cx->GetZ()) > tolerance) continue;
+           if (TMath::Abs(tmp.GetY() - cx->GetY()) > tolerance) continue;
+
+           Double_t chi2=tmp.GetPredictedChi2(cx);
+           if (chi2<maxchi2) { maxchi2=chi2; cci=ci; }
+        }
+        if (cci>=0) t->SetExtraCluster(i,(i<<28)+cci);
+     }
+
+     // 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 (y<fYmin) continue;
-    if (y>fYmax) continue;
-    ncl++;
   }
-  return ncl;
+
+  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);
+
+  Int_t clusterIndex = t->GetClusterIndex(0);
+  AliITSRecPoint *c= 0x0;
+
+  if (clusterIndex>-1)
+    c = (AliITSRecPoint *)GetCluster(clusterIndex);
+  if (c && c->GetSigmaZ2()>0.1) c->UnUse();
 
+  c = 0x0;
+  clusterIndex = t->GetClusterIndex(1);
+  if (clusterIndex>-1)
+    c=(AliITSRecPoint *)GetCluster(clusterIndex);
+  if (c && c->GetSigmaZ2()>0.1) c->UnUse();
 
+}