]> git.uio.no Git - u/mrichter/AliRoot.git/blobdiff - TRD/AliTRDtrackerV1.cxx
protect the propagation code against failure in calling
[u/mrichter/AliRoot.git] / TRD / AliTRDtrackerV1.cxx
index 26b4f0c4267a26c368808dee30586bf008a25e75..1b6b50367b47f958be776bd42674636db7b8e18f 100644 (file)
@@ -1,18 +1,18 @@
 
 /**************************************************************************
- * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
- *                                                                        *
- * Author: The ALICE Off-line Project.                                    *
- * Contributors are mentioned in the code where appropriate.              *
- *                                                                        *
- * Permission to use, copy, modify and distribute this software and its   *
- * documentation strictly for non-commercial purposes is hereby granted   *
- * without fee, provided that the above copyright notice appears in all   *
- * copies and that both the copyright notice and this permission notice   *
- * appear in the supporting documentation. The authors make no claims     *
- * about the suitability of this software for any purpose. It is          *
- * provided "as is" without express or implied warranty.                  *
- **************************************************************************/
+* Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
+*                                                                        *
+* Author: The ALICE Off-line Project.                                    *
+* Contributors are mentioned in the code where appropriate.              *
+*                                                                        *
+* Permission to use, copy, modify and distribute this software and its   *
+* documentation strictly for non-commercial purposes is hereby granted   *
+* without fee, provided that the above copyright notice appears in all   *
+* copies and that both the copyright notice and this permission notice   *
+* appear in the supporting documentation. The authors make no claims     *
+* about the suitability of this software for any purpose. It is          *
+* provided "as is" without express or implied warranty.                  *
+**************************************************************************/
 
 /* $Id$ */
 
 //                                                                           //
 ///////////////////////////////////////////////////////////////////////////////
 
-#include <Riostream.h>
-#include <stdio.h>
-#include <string.h>
+// #include <Riostream.h>
+// #include <stdio.h>
+// #include <string.h>
 
 #include <TBranch.h>
-#include <TFile.h>
-#include <TGraph.h>
-#include <TH1D.h>
-#include <TH2D.h>
+#include <TDirectory.h>
 #include <TLinearFitter.h>
-#include <TObjArray.h> 
-#include <TROOT.h>
 #include <TTree.h>  
 #include <TClonesArray.h>
-#include <TRandom.h>
 #include <TTreeStream.h>
 
 #include "AliLog.h"
 #include "AliESDEvent.h"
-#include "AliAlignObj.h"
+#include "AliGeomManager.h"
 #include "AliRieman.h"
 #include "AliTrackPointArray.h"
 
-#include "AliTRDtracker.h"
-#include "AliTRDtrackerV1.h"
 #include "AliTRDgeometry.h"
 #include "AliTRDpadPlane.h"
-#include "AliTRDgeometry.h"
-#include "AliTRDcluster.h" 
-#include "AliTRDtrack.h"
-#include "AliTRDseed.h"
 #include "AliTRDcalibDB.h"
-#include "AliTRDCommonParam.h"
 #include "AliTRDReconstructor.h"
 #include "AliTRDCalibraFillHisto.h"
-#include "AliTRDtrackerFitter.h"
-#include "AliTRDstackLayer.h"
 #include "AliTRDrecoParam.h"
+
+#include "AliTRDcluster.h" 
 #include "AliTRDseedV1.h"
 #include "AliTRDtrackV1.h"
-#include "Cal/AliTRDCalDet.h"
+#include "AliTRDtrackerV1.h"
+#include "AliTRDtrackerDebug.h"
+#include "AliTRDtrackingChamber.h"
+#include "AliTRDchamberTimeBin.h"
+
 
-#define DEBUG
 
 ClassImp(AliTRDtrackerV1)
+
+
+const  Float_t  AliTRDtrackerV1::fgkMinClustersInTrack =  0.5;  //
+const  Float_t  AliTRDtrackerV1::fgkLabelFraction      =  0.8;  //
+const  Double_t AliTRDtrackerV1::fgkMaxChi2            = 12.0;  //
+const  Double_t AliTRDtrackerV1::fgkMaxSnp             =  0.95; // Maximum local sine of the azimuthal angle
+const  Double_t AliTRDtrackerV1::fgkMaxStep            =  2.0;  // Maximal step size in propagation 
 Double_t AliTRDtrackerV1::fgTopologicQA[kNConfigs] = {
-               0.1112, 0.1112, 0.1112, 0.0786, 0.0786,
-               0.0786, 0.0786, 0.0579, 0.0579, 0.0474,
-               0.0474, 0.0408, 0.0335, 0.0335, 0.0335
+  0.1112, 0.1112, 0.1112, 0.0786, 0.0786,
+  0.0786, 0.0786, 0.0579, 0.0579, 0.0474,
+  0.0474, 0.0408, 0.0335, 0.0335, 0.0335
 };
+Int_t AliTRDtrackerV1::fgNTimeBins = 0;
+TTreeSRedirector *AliTRDtrackerV1::fgDebugStreamer = 0x0;
+AliRieman* AliTRDtrackerV1::fgRieman = 0x0;
+TLinearFitter* AliTRDtrackerV1::fgTiltedRieman = 0x0;
+TLinearFitter* AliTRDtrackerV1::fgTiltedRiemanConstrained = 0x0;
 
 //____________________________________________________________________
-AliTRDtrackerV1::AliTRDtrackerV1(AliTRDrecoParam *p) 
-  :AliTRDtracker()
-  ,fSieveSeeding(0)
+AliTRDtrackerV1::AliTRDtrackerV1(AliTRDReconstructor *rec) 
+  :AliTracker()
+  ,fReconstructor(0x0)
+  ,fGeom(new AliTRDgeometry())
+  ,fClusters(0x0)
   ,fTracklets(0x0)
-  ,fRecoParam(p)
-  ,fFitter(0x0)
-{
-  //
-  // Default constructor. Nothing is initialized.
-  //
-
-}
-
-//____________________________________________________________________
-AliTRDtrackerV1::AliTRDtrackerV1(const TFile *in, AliTRDrecoParam *p) 
-  :AliTRDtracker(in)
+  ,fTracks(0x0)
   ,fSieveSeeding(0)
-  ,fTracklets(0x0)
-  ,fRecoParam(p)
-  ,fFitter(0x0)
 {
   //
-  // Standard constructor.
-  // Setting of the geometry file, debug output (if enabled)
-  // and initilize fitter helper.
-  //
+  // Default constructor.
+  // 
+  AliTRDcalibDB *trd = 0x0;
+  if (!(trd = AliTRDcalibDB::Instance())) {
+    AliFatal("Could not get calibration object");
+  }
 
-       fFitter = new AliTRDtrackerFitter();
+  if(!fgNTimeBins) fgNTimeBins = trd->GetNumberOfTimeBins();
 
-#ifdef DEBUG
-       fFitter->SetDebugStream(fDebugStreamer);
-#endif
+  for (Int_t isector = 0; isector < AliTRDgeometry::kNsector; isector++) new(&fTrSec[isector]) AliTRDtrackingSector(fGeom, isector);
+  
+  for(Int_t isl =0; isl<kNSeedPlanes; isl++) fSeedTB[isl] = 0x0;
 
+  // Initialize debug stream
+  if(rec) SetReconstructor(rec);
 }
-  
+
 //____________________________________________________________________
 AliTRDtrackerV1::~AliTRDtrackerV1()
 { 
   //
   // Destructor
   //
-
-       if(fFitter) delete fFitter;
-       if(fRecoParam) delete fRecoParam;
-       if(fTracklets) {fTracklets->Delete(); delete fTracklets;}
+  
+  if(fgDebugStreamer) delete fgDebugStreamer;
+  if(fgRieman) delete fgRieman;
+  if(fgTiltedRieman) delete fgTiltedRieman;
+  if(fgTiltedRiemanConstrained) delete fgTiltedRiemanConstrained;
+  for(Int_t isl =0; isl<kNSeedPlanes; isl++) if(fSeedTB[isl]) delete fSeedTB[isl];
+  if(fTracks) {fTracks->Delete(); delete fTracks;}
+  if(fTracklets) {fTracklets->Delete(); delete fTracklets;}
+  if(fClusters) {
+    fClusters->Delete(); delete fClusters;
+  }
+  if(fGeom) delete fGeom;
 }
 
 //____________________________________________________________________
@@ -143,34 +145,95 @@ Int_t AliTRDtrackerV1::Clusters2Tracks(AliESDEvent *esd)
   //    See AliTRDtrackerV1::Clusters2TracksSM() for details.
   //
 
-       if(!fRecoParam){
-               AliError("Reconstruction configuration not initialized. Call first AliTRDtrackerV1::SetRecoParam().");
-               return 0;
-       }
-       
-       //AliInfo("Start Track Finder ...");
-       Int_t ntracks = 0;
-       for(int ism=0; ism<AliTRDtracker::kTrackingSectors; ism++){
-                       //AliInfo(Form("Processing supermodule %i ...", ism));
-                       ntracks += Clusters2TracksSM(fTrSec[ism], esd);
-       }
-       AliInfo(Form("Found %d TRD tracks.", ntracks));
-       return ntracks;
+  if(!fReconstructor->GetRecoParam() ){
+    AliError("Reconstruction configuration not initialized. Call first AliTRDReconstructor::SetRecoParam().");
+    return 0;
+  }
+  
+  //AliInfo("Start Track Finder ...");
+  Int_t ntracks = 0;
+  for(int ism=0; ism<AliTRDgeometry::kNsector; ism++){
+    // for(int ism=1; ism<2; ism++){
+    //AliInfo(Form("Processing supermodule %i ...", ism));
+    ntracks += Clusters2TracksSM(ism, esd);
+  }
+  AliInfo(Form("Number of found tracks : %d", ntracks));
+  return ntracks;
 }
 
 
 //_____________________________________________________________________________
-Bool_t AliTRDtrackerV1::GetTrackPoint(Int_t index, AliTrackPoint &/*p*/) const
+Bool_t AliTRDtrackerV1::GetTrackPoint(Int_t index, AliTrackPoint &p) const
 {
-       //AliInfo(Form("Asking for tracklet %d", index));
-       
-       if(index<0) return kFALSE;
-       //AliTRDseedV1 *tracklet = (AliTRDseedV1*)fTracklets->UncheckedAt(index);
-       // etc
-       return kTRUE;
+  //AliInfo(Form("Asking for tracklet %d", index));
+  
+  AliTRDseedV1 *tracklet = GetTracklet(index); 
+  if (!tracklet) return kFALSE;
+  
+  // get detector for this tracklet
+  AliTRDcluster *cl = 0x0;
+  Int_t ic = 0; do {} while(!(cl = tracklet->GetClusters(ic++)));
+  Int_t  idet     = cl->GetDetector();
+    
+  Double_t local[3];
+  local[0] = tracklet->GetX0(); 
+  local[1] = tracklet->GetYfit(0);
+  local[2] = tracklet->GetZfit(0);
+  Double_t global[3];
+  fGeom->RotateBack(idet, local, global);
+  p.SetXYZ(global[0],global[1],global[2]);
+  
+  
+  // setting volume id
+  AliGeomManager::ELayerID iLayer = AliGeomManager::kTRD1;
+  switch (fGeom->GetLayer(idet)) {
+  case 0:
+    iLayer = AliGeomManager::kTRD1;
+    break;
+  case 1:
+    iLayer = AliGeomManager::kTRD2;
+    break;
+  case 2:
+    iLayer = AliGeomManager::kTRD3;
+    break;
+  case 3:
+    iLayer = AliGeomManager::kTRD4;
+    break;
+  case 4:
+    iLayer = AliGeomManager::kTRD5;
+    break;
+  case 5:
+    iLayer = AliGeomManager::kTRD6;
+    break;
+  };
+  Int_t    modId = fGeom->GetSector(idet) * fGeom->Nstack() + fGeom->GetStack(idet);
+  UShort_t volid = AliGeomManager::LayerToVolUID(iLayer, modId);
+  p.SetVolumeID(volid);
+    
+  return kTRUE;
 }
 
+//____________________________________________________________________
+TLinearFitter* AliTRDtrackerV1::GetTiltedRiemanFitter()
+{
+  if(!fgTiltedRieman) fgTiltedRieman = new TLinearFitter(4, "hyp4");
+  return fgTiltedRieman;
+}
 
+//____________________________________________________________________
+TLinearFitter* AliTRDtrackerV1::GetTiltedRiemanFitterConstraint()
+{
+  if(!fgTiltedRiemanConstrained) fgTiltedRiemanConstrained = new TLinearFitter(2, "hyp2");
+  return fgTiltedRiemanConstrained;
+}
+  
+//____________________________________________________________________ 
+AliRieman* AliTRDtrackerV1::GetRiemanFitter()
+{
+  if(!fgRieman) fgRieman = new AliRieman(AliTRDtrackingChamber::kNTimeBins * AliTRDgeometry::kNlayer);
+  return fgRieman;
+}
+  
 //_____________________________________________________________________________
 Int_t AliTRDtrackerV1::PropagateBack(AliESDEvent *event) 
 {
@@ -183,242 +246,178 @@ Int_t AliTRDtrackerV1::PropagateBack(AliESDEvent *event)
   // by the TPC tracker.   
   //  
 
-       Int_t   found    = 0;     // number of tracks found
-       Float_t foundMin = 20.0;
-       
-       AliTRDseed::SetNTimeBins(fTimeBinsPerPlane);
-       Int_t    nSeed   = event->GetNumberOfTracks();
-       if(!nSeed){
-               // run stand alone tracking
-               if (AliTRDReconstructor::SeedingOn()) Clusters2Tracks(event);
-               return 0;
-       }
-       
-       Float_t *quality = new Float_t[nSeed];
-       Int_t   *index   = new Int_t[nSeed];
-       for (Int_t iSeed = 0; iSeed < nSeed; iSeed++) {
-               AliESDtrack *seed = event->GetTrack(iSeed);
-               Double_t covariance[15];
-               seed->GetExternalCovariance(covariance);
-               quality[iSeed] = covariance[0] + covariance[2];
-       }
-       // Sort tracks according to covariance of local Y and Z
-       TMath::Sort(nSeed,quality,index,kFALSE);
-       
-       // Backpropagate all seeds
-       for (Int_t iSeed = 0; iSeed < nSeed; iSeed++) {
-       
-               // Get the seeds in sorted sequence
-               AliESDtrack *seed = event->GetTrack(index[iSeed]);
-       
-               // Check the seed status
-               ULong_t status = seed->GetStatus();
-               if ((status & AliESDtrack::kTPCout) == 0) continue;
-               if ((status & AliESDtrack::kTRDout) != 0) continue;
-       
-               // Do the back prolongation
-               Int_t   lbl         = seed->GetLabel();
-               AliTRDtrackV1 *track  = new AliTRDtrackV1(*seed);
-               //track->Print();
-               track->SetSeedLabel(lbl);
-               seed->UpdateTrackParams(track, AliESDtrack::kTRDbackup); // Make backup
-               fNseeds++;
-               Float_t p4          = track->GetC();
-               Int_t   expectedClr = FollowBackProlongation(*track);
-               //AliInfo(Form("\nTRACK %d Clusters %d [%d] in chi2 %f", index[iSeed], expectedClr, track->GetNumberOfClusters(), track->GetChi2()));
-               //track->Print();
-
-               //Double_t cov[15];
-               //seed->GetExternalCovariance(cov);
-               //AliInfo(Form("track %d cov[%f %f] 0", index[iSeed], cov[0], cov[2]));
-
-               if ((TMath::Abs(track->GetC() - p4) / TMath::Abs(p4) < 0.2) ||
-                               (track->Pt() > 0.8)) {
-                       //
-                       // Make backup for back propagation
-                       //
-                       Int_t foundClr = track->GetNumberOfClusters();
-                       if (foundClr >= foundMin) {
-                               //AliInfo(Form("Making backup track ncls [%d]...", foundClr));
-                               track->CookdEdx();
-                               track->CookdEdxTimBin(seed->GetID()); // A.Bercuci 25.07.07
-                               CookLabel(track,1 - fgkLabelFraction);
-                               if (track->GetBackupTrack()) UseClusters(track->GetBackupTrack());
-                               
-                               
-               //seed->GetExternalCovariance(cov);
-               //AliInfo(Form("track %d cov[%f %f] 0 test", index[iSeed], cov[0], cov[2]));
-
-                               // Sign only gold tracks
-                               if (track->GetChi2() / track->GetNumberOfClusters() < 4) {
-                                       if ((seed->GetKinkIndex(0)      ==   0) &&
-                                                       (track->Pt()                <  1.5)) UseClusters(track);
-                               }
-                               Bool_t isGold = kFALSE;
-       
-                               // Full gold track
-                               if (track->GetChi2() / track->GetNumberOfClusters() < 5) {
-                                       if (track->GetBackupTrack()) seed->UpdateTrackParams(track->GetBackupTrack(),AliESDtrack::kTRDbackup);
-
-                                       isGold = kTRUE;
-                               }
-               //seed->GetExternalCovariance(cov);
-               //AliInfo(Form("track %d cov[%f %f] 00", index[iSeed], cov[0], cov[2]));
-       
-                               // Almost gold track
-                               if ((!isGold)  && (track->GetNCross() == 0) &&
-                                               (track->GetChi2() / track->GetNumberOfClusters()  < 7)) {
-                                       //seed->UpdateTrackParams(track, AliESDtrack::kTRDbackup);
-                                       if (track->GetBackupTrack()) seed->UpdateTrackParams(track->GetBackupTrack(),AliESDtrack::kTRDbackup);
-                                       
-                                       isGold = kTRUE;
-                               }
-               //seed->GetExternalCovariance(cov);
-               //AliInfo(Form("track %d cov[%f %f] 01", index[iSeed], cov[0], cov[2]));
-                               
-                               if ((!isGold) && (track->GetBackupTrack())) {
-                                       if ((track->GetBackupTrack()->GetNumberOfClusters() > foundMin) && ((track->GetBackupTrack()->GetChi2()/(track->GetBackupTrack()->GetNumberOfClusters()+1)) < 7)) {
-                                               seed->UpdateTrackParams(track->GetBackupTrack(),AliESDtrack::kTRDbackup);
-                                               isGold = kTRUE;
-                                       }
-                               }
-               //seed->GetExternalCovariance(cov);
-               //AliInfo(Form("track %d cov[%f %f] 02", index[iSeed], cov[0], cov[2]));
-       
-                               //if ((track->StatusForTOF() > 0) && (track->GetNCross() == 0) && (Float_t(track->GetNumberOfClusters()) / Float_t(track->GetNExpected())  > 0.4)) {
-                                       //seed->UpdateTrackParams(track->GetBackupTrack(), AliESDtrack::kTRDbackup);
-                               //}
-                       }
-               }
-               /**/
-       
-               /**/
-               // Debug part of tracking
-/*             TTreeSRedirector &cstream = *fDebugStreamer;
-               Int_t eventNrInFile = event->GetEventNumberInFile(); // This is most likely NOT the event number you'd like to use. It has nothing to do with the 'real' event number.
-               if (AliTRDReconstructor::StreamLevel() > 0) {
-                       if (track->GetBackupTrack()) {
-                               cstream << "Tracks"
-                               << "EventNrInFile="  << eventNrInFile
-                               << "ESD.="     << seed
-                               << "trd.="     << track
-                               << "trdback.=" << track->GetBackupTrack()
-                               << "\n";
-                       }
-                       else {
-                               cstream << "Tracks"
-                               << "EventNrInFile="  << eventNrInFile
-                               << "ESD.="     << seed
-                               << "trd.="     << track
-                               << "trdback.=" << track
-                               << "\n";
-                       }
-               }*/
-               /**/
-       
-               //seed->GetExternalCovariance(cov);
-               //AliInfo(Form("track %d cov[%f %f] 1", index[iSeed], cov[0], cov[2]));
-
-               // Propagation to the TOF (I.Belikov)
-               if (track->GetStop() == kFALSE) {
-                       //AliInfo("Track not stopped in TRD ...");
-                       Double_t xtof  = 371.0;
-                       Double_t xTOF0 = 370.0;
-               
-                       Double_t c2    = track->GetSnp() + track->GetC() * (xtof - track->GetX());
-                       if (TMath::Abs(c2) >= 0.99) {
-                               delete track;
-                               continue;
-                       }
-                       
-                       PropagateToX(*track,xTOF0,fgkMaxStep);
-       
-                       // Energy losses taken to the account - check one more time
-                       c2 = track->GetSnp() + track->GetC() * (xtof - track->GetX());
-                       if (TMath::Abs(c2) >= 0.99) {
-                               delete track;
-                               continue;
-                       }
-                       
-                       //if (!PropagateToX(*track,xTOF0,fgkMaxStep)) {
-                       //      fHBackfit->Fill(7);
-                       //delete track;
-                       //      continue;
-                       //}
-       
-                       Double_t ymax = xtof * TMath::Tan(0.5 * AliTRDgeometry::GetAlpha());
-                       Double_t y;
-                       track->GetYAt(xtof,GetBz(),y);
-                       if (y >  ymax) {
-                               if (!track->Rotate( AliTRDgeometry::GetAlpha())) {
-                                       delete track;
-                                       continue;
-                               }
-                       }else if (y < -ymax) {
-                               if (!track->Rotate(-AliTRDgeometry::GetAlpha())) {
-                                       delete track;
-                                       continue;
-                               }
-                       }
-                                       
-                       if (track->PropagateTo(xtof)) {
-                               //AliInfo("set kTRDout");
-                               seed->UpdateTrackParams(track,AliESDtrack::kTRDout);
-       
-                               for (Int_t i = 0; i < AliESDtrack::kNPlane; i++) {
-                                       for (Int_t j = 0; j < AliESDtrack::kNSlice; j++) {
-                                               seed->SetTRDsignals(track->GetPIDsignals(i,j),i,j);
-                                       }
-                                       seed->SetTRDTimBin(track->GetPIDTimBin(i),i);
-                               }
-                               //seed->SetTRDtrack(new AliTRDtrack(*track));
-                               if (track->GetNumberOfClusters() > foundMin) found++;
-                       }
-               } else {
-                       //AliInfo("Track stopped in TRD ...");
-                       
-                       if ((track->GetNumberOfClusters() >              15) &&
-                                       (track->GetNumberOfClusters() > 0.5*expectedClr)) {
-                               seed->UpdateTrackParams(track,AliESDtrack::kTRDout);
-       
-                               //seed->SetStatus(AliESDtrack::kTRDStop);
-                               for (Int_t i = 0; i < AliESDtrack::kNPlane; i++) {
-                                       for (Int_t j = 0; j <AliESDtrack::kNSlice; j++) {
-                                               seed->SetTRDsignals(track->GetPIDsignals(i,j),i,j);
-                                       }
-                                       seed->SetTRDTimBin(track->GetPIDTimBin(i),i);
-                               }
-                               //seed->SetTRDtrack(new AliTRDtrack(*track));
-                               found++;
-                       }
-               }
-
-               //if (((t->GetStatus()&AliESDtrack::kTRDout)!=0 )
-       
-               seed->SetTRDQuality(track->StatusForTOF());
-               seed->SetTRDBudget(track->GetBudget(0));
-               
-//             if ((seed->GetStatus()&AliESDtrack::kTRDin)!=0 ) printf("TRDin ");      
-//             if ((seed->GetStatus()&AliESDtrack::kTRDbackup)!=0 ) printf("TRDbackup ");      
-//             if ((seed->GetStatus()&AliESDtrack::kTRDStop)!=0 ) printf("TRDstop ");  
-//             if ((seed->GetStatus()&AliESDtrack::kTRDout)!=0 ) printf("TRDout ");    
-//             printf("\n");
-               delete track;
-
-               //seed->GetExternalCovariance(cov);
-               //AliInfo(Form("track %d cov[%f %f] 2", index[iSeed], cov[0], cov[2]));
-       }
-       
+  // Calibration monitor
+  AliTRDCalibraFillHisto *calibra = AliTRDCalibraFillHisto::Instance();
+  if (!calibra) AliInfo("Could not get Calibra instance\n");
+  
+  Int_t   found    = 0;     // number of tracks found
+  Float_t foundMin = 20.0;
+  
+  Float_t *quality = 0x0;
+  Int_t   *index   = 0x0;
+  Int_t    nSeed   = event->GetNumberOfTracks();
+  if(nSeed){  
+    quality = new Float_t[nSeed];
+    index   = new Int_t[nSeed];
+    for (Int_t iSeed = 0; iSeed < nSeed; iSeed++) {
+      AliESDtrack *seed = event->GetTrack(iSeed);
+      Double_t covariance[15];
+      seed->GetExternalCovariance(covariance);
+      quality[iSeed] = covariance[0] + covariance[2];
+    }
+    // Sort tracks according to covariance of local Y and Z
+    TMath::Sort(nSeed,quality,index,kFALSE);
+  }
+  
+  // Backpropagate all seeds
+  Int_t   expectedClr;
+  AliTRDtrackV1 track;
+  for (Int_t iSeed = 0; iSeed < nSeed; iSeed++) {
+  
+    // Get the seeds in sorted sequence
+    AliESDtrack *seed = event->GetTrack(index[iSeed]);
+  
+    // Check the seed status
+    ULong_t status = seed->GetStatus();
+    if ((status & AliESDtrack::kTPCout) == 0) continue;
+    if ((status & AliESDtrack::kTRDout) != 0) continue;
+  
+    // Do the back prolongation
+    new(&track) AliTRDtrackV1(*seed);
+    track.SetReconstructor(fReconstructor);
+
+    //Int_t   lbl         = seed->GetLabel();
+    //track.SetSeedLabel(lbl);
+
+    // Make backup and mark entrance in the TRD
+    seed->UpdateTrackParams(&track, AliESDtrack::kTRDin);
+    seed->UpdateTrackParams(&track, AliESDtrack::kTRDbackup);
+    Float_t p4          = track.GetC();
+    expectedClr = FollowBackProlongation(track);
+
+    if (expectedClr<0) continue; // Back prolongation failed
+
+    if(expectedClr){
+      found++;  
+      // computes PID for track
+      track.CookPID();
+      // update calibration references using this track
+      if(calibra->GetHisto2d()) calibra->UpdateHistogramsV1(&track);
+      // save calibration object
+      if (fReconstructor->GetStreamLevel(AliTRDReconstructor::kTracker) > 0 /*&& quality TODO*/){ 
+        AliTRDtrackV1 *calibTrack = new AliTRDtrackV1(track);
+        calibTrack->SetOwner();
+        seed->AddCalibObject(calibTrack);
+      }
+      //update ESD track
+      if ((track.GetNumberOfClusters() > 15) && (track.GetNumberOfClusters() > 0.5*expectedClr)) {
+        seed->UpdateTrackParams(&track, AliESDtrack::kTRDout);
+        track.UpdateESDtrack(seed);
+      }
+    }
 
-       AliInfo(Form("Number of seeds: %d",fNseeds));
-       AliInfo(Form("Number of back propagated TRD tracks: %d",found));
-               
-       //fSeeds->Clear(); 
-       fNseeds = 0;
-       
-       delete [] index;
-       delete [] quality;
-       
+    if ((TMath::Abs(track.GetC() - p4) / TMath::Abs(p4) < 0.2) ||(track.Pt() > 0.8)) {
+      //
+      // Make backup for back propagation
+      //
+      Int_t foundClr = track.GetNumberOfClusters();
+      if (foundClr >= foundMin) {
+        //AliInfo(Form("Making backup track ncls [%d]...", foundClr));
+        //track.CookdEdx();
+        //track.CookdEdxTimBin(seed->GetID());
+        track.CookLabel(1. - fgkLabelFraction);
+        if(track.GetBackupTrack()) UseClusters(track.GetBackupTrack());
+
+        // Sign only gold tracks
+        if (track.GetChi2() / track.GetNumberOfClusters() < 4) {
+          if ((seed->GetKinkIndex(0)      ==   0) && (track.Pt() <  1.5)){
+            //UseClusters(&track);
+          }
+        }
+        Bool_t isGold = kFALSE;
+  
+        // Full gold track
+        if (track.GetChi2() / track.GetNumberOfClusters() < 5) {
+          if (track.GetBackupTrack()) seed->UpdateTrackParams(track.GetBackupTrack(),AliESDtrack::kTRDbackup);
+
+          isGold = kTRUE;
+        }
+  
+        // Almost gold track
+        if ((!isGold)  && (track.GetNCross() == 0) &&  (track.GetChi2() / track.GetNumberOfClusters()  < 7)) {
+          //seed->UpdateTrackParams(track, AliESDtrack::kTRDbackup);
+          if (track.GetBackupTrack()) seed->UpdateTrackParams(track.GetBackupTrack(),AliESDtrack::kTRDbackup);
+  
+          isGold = kTRUE;
+        }
+        
+        if ((!isGold) && (track.GetBackupTrack())) {
+          if ((track.GetBackupTrack()->GetNumberOfClusters() > foundMin) && ((track.GetBackupTrack()->GetChi2()/(track.GetBackupTrack()->GetNumberOfClusters()+1)) < 7)) {
+            seed->UpdateTrackParams(track.GetBackupTrack(),AliESDtrack::kTRDbackup);
+            isGold = kTRUE;
+          }
+        }
+  
+        //if ((track->StatusForTOF() > 0) && (track->GetNCross() == 0) && (Float_t(track->GetNumberOfClusters()) / Float_t(track->GetNExpected())  > 0.4)) {
+        //seed->UpdateTrackParams(track->GetBackupTrack(), AliESDtrack::kTRDbackup);
+        //}
+      }
+    }
+    
+    // Propagation to the TOF (I.Belikov)
+    if (track.IsStopped() == kFALSE) {
+      Double_t xtof  = 371.0;
+      Double_t xTOF0 = 370.0;
+    
+      Double_t c2    = track.GetSnp() + track.GetC() * (xtof - track.GetX());
+      if (TMath::Abs(c2) >= 0.99) continue;
+      
+      if (!PropagateToX(track, xTOF0, fgkMaxStep)) continue;
+  
+      // Energy losses taken to the account - check one more time
+      c2 = track.GetSnp() + track.GetC() * (xtof - track.GetX());
+      if (TMath::Abs(c2) >= 0.99) continue;
+      
+      //if (!PropagateToX(*track,xTOF0,fgkMaxStep)) {
+      //       fHBackfit->Fill(7);
+      //delete track;
+      //       continue;
+      //}
+  
+      Double_t ymax = xtof * TMath::Tan(0.5 * AliTRDgeometry::GetAlpha());
+      Double_t y;
+      track.GetYAt(xtof,GetBz(),y);
+      if (y >  ymax) {
+        if (!track.Rotate( AliTRDgeometry::GetAlpha())) continue;      
+      }else if (y < -ymax) {
+        if (!track.Rotate(-AliTRDgeometry::GetAlpha())) continue;
+      }
+          
+      if (track.PropagateTo(xtof)) {
+        seed->UpdateTrackParams(&track, AliESDtrack::kTRDout);
+        track.UpdateESDtrack(seed);
+      }
+    } else {                   
+      if ((track.GetNumberOfClusters() > 15) && (track.GetNumberOfClusters() > 0.5*expectedClr)) {
+        seed->UpdateTrackParams(&track, AliESDtrack::kTRDout);
+  
+        track.UpdateESDtrack(seed);
+      }
+    }
+  
+    seed->SetTRDQuality(track.StatusForTOF());
+    seed->SetTRDBudget(track.GetBudget(0));
+  }
+  if(index) delete [] index;
+  if(quality) delete [] quality;
+  
+
+  AliInfo(Form("Number of seeds: %d", nSeed));
+  AliInfo(Form("Number of back propagated TRD tracks: %d", found));
+      
+  // run stand alone tracking
+  if (fReconstructor->IsSeeding()) Clusters2Tracks(event);
+  
   return 0;
 }
 
@@ -437,55 +436,41 @@ Int_t AliTRDtrackerV1::RefitInward(AliESDEvent *event)
   Int_t   nseed    = 0; // contor for loaded seeds
   Int_t   found    = 0; // contor for updated TRD tracks
   
-  // Calibration monitor
-  AliTRDCalibraFillHisto *calibra = AliTRDCalibraFillHisto::Instance();
-  if (!calibra) AliInfo("Could not get Calibra instance\n");
-  
   
   AliTRDtrackV1 track;
   for (Int_t itrack = 0; itrack < event->GetNumberOfTracks(); itrack++) {
     AliESDtrack *seed = event->GetTrack(itrack);
-               new(&track) AliTRDtrackV1(*seed);
+    new(&track) AliTRDtrackV1(*seed);
 
     if (track.GetX() < 270.0) {
       seed->UpdateTrackParams(&track, AliESDtrack::kTRDbackup);
-      //AliInfo(Form("Remove for X = %7.3f [270.]\n", track.GetX()));
-                       continue;
+      continue;
     }
 
     ULong_t status = seed->GetStatus();
+    // reject tracks which failed propagation in the TRD
     if((status & AliESDtrack::kTRDout) == 0) continue;
-    if((status & AliESDtrack::kTRDin)  != 0) continue;
+
+    // reject tracks which are produced by the TRD stand alone track finder.
+    if((status & AliESDtrack::kTRDin)  == 0) continue;
     nseed++; 
 
     track.ResetCovariance(50.0);
 
-               // do the propagation and processing
+    // do the propagation and processing
     Bool_t kUPDATE = kFALSE;
-               Double_t xTPC = 250.0;
-    if(FollowProlongation(track)){
-                       // computes PID for track
-                       track.CookPID();
-                       // update calibration references using this track
-                       if(calibra->GetHisto2d()) calibra->UpdateHistogramsV1(&track);
-       
-                       // Prolongate to TPC
-                       if (PropagateToX(track, xTPC, fgkMaxStep)) { //  -with update
-                               seed->UpdateTrackParams(&track, AliESDtrack::kTRDrefit);
-                               track.UpdateESDtrack(seed);
-                               // Add TRD track to ESDfriendTrack
-                               if (AliTRDReconstructor::StreamLevel() > 0 /*&& quality TODO*/){ 
-                                       AliTRDtrackV1 *calibTrack = new AliTRDtrackV1(track);
-                                       calibTrack->SetOwner();
-                                       seed->AddCalibObject(calibTrack);
-                               }
-                               found++;
-                               kUPDATE = kTRUE;
-                       }
-               }        
-               
-               // Prolongate to TPC without update
-               if(!kUPDATE) {
+    Double_t xTPC = 250.0;
+    if(FollowProlongation(track)){     
+      // Prolongate to TPC
+      if (PropagateToX(track, xTPC, fgkMaxStep)) { //  -with update
+  seed->UpdateTrackParams(&track, AliESDtrack::kTRDrefit);
+  found++;
+  kUPDATE = kTRUE;
+      }
+    }   
+    
+    // Prolongate to TPC without update
+    if(!kUPDATE) {
       AliTRDtrackV1 tt(*seed);
       if (PropagateToX(tt, xTPC, fgkMaxStep)) seed->UpdateTrackParams(&tt, AliESDtrack::kTRDrefit);
     }
@@ -493,110 +478,98 @@ Int_t AliTRDtrackerV1::RefitInward(AliESDEvent *event)
   AliInfo(Form("Number of loaded seeds: %d",nseed));
   AliInfo(Form("Number of found tracks from loaded seeds: %d",found));
   
-       return 0;
+  return 0;
 }
 
-
 //____________________________________________________________________
 Int_t AliTRDtrackerV1::FollowProlongation(AliTRDtrackV1 &t)
 {
-// Extrapolates the TRD track in the TPC direction.
-//
-// Parameters
-//   t : the TRD track which has to be extrapolated
-// 
-// Output
-//   number of clusters attached to the track
-//
-// Detailed description
-//
-// Starting from current radial position of track <t> this function
-// extrapolates the track through the 6 TRD layers. The following steps
-// are being performed for each plane:
-// 1. prepare track:
-//   a. get plane limits in the local x direction
-//   b. check crossing sectors 
-//   c. check track inclination
-// 2. search tracklet in the tracker list (see GetTracklet() for details)
-// 3. evaluate material budget using the geo manager
-// 4. propagate and update track using the tracklet information.
-//
-// Debug level 2
-//
-  
-       //AliInfo("");
-       Int_t    nClustersExpected = 0;
-       Float_t clength = AliTRDgeometry::AmThick() + AliTRDgeometry::DrThick();
-       Int_t lastplane = 5; //GetLastPlane(&t);
-       for (Int_t iplane = lastplane; iplane >= 0; iplane--) {
-               //AliInfo(Form("plane %d", iplane));
-    Int_t row1 = GetGlobalTimeBin(0, iplane, 0); // to be modified to the true time bin in the geometrical acceptance
-               //AliInfo(Form("row1 %d", row1));
-
-    // Propagate track close to the plane if neccessary
-               AliTRDpropagationLayer *layer = fTrSec[0]->GetLayer(row1);
-               Double_t currentx  = layer->GetX();
-    if (currentx < (-fgkMaxStep + t.GetX())) 
-      if (!PropagateToX(t, currentx+fgkMaxStep, fgkMaxStep)) break;
+  // Extrapolates the TRD track in the TPC direction.
+  //
+  // Parameters
+  //   t : the TRD track which has to be extrapolated
+  // 
+  // Output
+  //   number of clusters attached to the track
+  //
+  // Detailed description
+  //
+  // Starting from current radial position of track <t> this function
+  // extrapolates the track through the 6 TRD layers. The following steps
+  // are being performed for each plane:
+  // 1. prepare track:
+  //   a. get plane limits in the local x direction
+  //   b. check crossing sectors 
+  //   c. check track inclination
+  // 2. search tracklet in the tracker list (see GetTracklet() for details)
+  // 3. evaluate material budget using the geo manager
+  // 4. propagate and update track using the tracklet information.
+  //
+  // Debug level 2
+  //
+  
+  Int_t    nClustersExpected = 0;
+  Int_t lastplane = 5; //GetLastPlane(&t);
+  for (Int_t iplane = lastplane; iplane >= 0; iplane--) {
+    Int_t   index   = 0;
+    AliTRDseedV1 *tracklet = GetTracklet(&t, iplane, index);
+    if(!tracklet) continue;
+    if(!tracklet->IsOK()) AliWarning("tracklet not OK");
+    
+    Double_t x  = tracklet->GetX0();
+    // reject tracklets which are not considered for inward refit
+    if(x > t.GetX()+fgkMaxStep) continue;
 
+    // append tracklet to track
+    t.SetTracklet(tracklet, index);
+    
+    if (x < (t.GetX()-fgkMaxStep) && !PropagateToX(t, x+fgkMaxStep, fgkMaxStep)) break;
     if (!AdjustSector(&t)) break;
-     
-               Int_t row0    = GetGlobalTimeBin(0,iplane,GetTimeBinsPerPlane()-1);
-               //AliInfo(Form("row0 %d", row0));
-
+    
     // Start global position
     Double_t xyz0[3];
     t.GetXYZ(xyz0);
 
-               // End global position
-    Double_t x = fTrSec[0]->GetLayer(row0)->GetX(), y, z;
+    // End global position
+    Double_t alpha = t.GetAlpha(), y, z;
     if (!t.GetProlongation(x,y,z)) break;    
     Double_t xyz1[3];
-    xyz1[0] =  x * TMath::Cos(t.GetAlpha()) - y * TMath::Sin(t.GetAlpha());
-    xyz1[1] = +x * TMath::Sin(t.GetAlpha()) + y * TMath::Cos(t.GetAlpha());
+    xyz1[0] =  x * TMath::Cos(alpha) - y * TMath::Sin(alpha);
+    xyz1[1] =  x * TMath::Sin(alpha) + y * TMath::Cos(alpha);
     xyz1[2] =  z;
-               
+        
     // Get material budget
     Double_t param[7];
-    AliTracker::MeanMaterialBudget(xyz0,xyz1,param);
+    if(AliTracker::MeanMaterialBudget(xyz0, xyz1, param)<=0.) break;
     Double_t xrho= param[0]*param[4];
     Double_t xx0 = param[1]; // Get mean propagation parameters
 
-    // Propagate and update
-    //Int_t sector = t.GetSector();
-    Int_t   index   = 0;
-               //AliInfo(Form("sector %d", sector));
-    AliTRDseedV1 *tracklet = GetTracklet(&t, iplane, index);
-         //AliInfo(Form("tracklet %p @ %d", tracklet, index));
-               if(!tracklet) continue;
-               //AliInfo(Form("reco %p", tracklet->GetRecoParam()));
-               t.SetTracklet(tracklet, iplane, index);
-               
-               t.PropagateTo(tracklet->GetX0() - clength, xx0, xrho);
-         if (!AdjustSector(&t)) break;
-         
+    // Propagate and update            
+    t.PropagateTo(x, xx0, xrho);
+    if (!AdjustSector(&t)) break;
+    
     Double_t maxChi2 = t.GetPredictedChi2(tracklet);
-         if (maxChi2 < 1e+10 && t.Update(tracklet, maxChi2)){ 
-               nClustersExpected += tracklet->GetN();
-       }
-  }
-
-#ifdef DEBUG
-       if(AliTRDReconstructor::StreamLevel() > 1){
-               Int_t index;
-               for(int iplane=0; iplane<6; iplane++){
-                       AliTRDseedV1 *tracklet = GetTracklet(&t, iplane, index);
-                       if(!tracklet) continue;
-                       t.SetTracklet(tracklet, iplane, index);
-               }
-
-               TTreeSRedirector &cstreamer = *fDebugStreamer;
-               cstreamer << "FollowProlongation"
-                       << "ncl="      << nClustersExpected
-                       << "track.="   << &t
-                       << "\n";
-       }
-#endif
+    if (maxChi2 < 1e+10 && t.Update(tracklet, maxChi2)){ 
+      nClustersExpected += tracklet->GetN();
+    }
+  }
+
+  if(fReconstructor->GetStreamLevel(AliTRDReconstructor::kTracker) > 1){
+    Int_t index;
+    for(int iplane=0; iplane<6; iplane++){
+      AliTRDseedV1 *tracklet = GetTracklet(&t, iplane, index);
+      if(!tracklet) continue;
+      t.SetTracklet(tracklet, index);
+    }
+
+    Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
+    TTreeSRedirector &cstreamer = *fgDebugStreamer;
+    cstreamer << "FollowProlongation"
+        << "EventNumber="      << eventNumber
+        << "ncl="                                      << nClustersExpected
+        //<< "track.="                 << &t
+        << "\n";
+  }
 
   return nClustersExpected;
 
@@ -605,196 +578,866 @@ Int_t AliTRDtrackerV1::FollowProlongation(AliTRDtrackV1 &t)
 //_____________________________________________________________________________
 Int_t AliTRDtrackerV1::FollowBackProlongation(AliTRDtrackV1 &t)
 {
-// Extrapolates the TRD track in the TOF direction.
-//
-// Parameters
-//   t : the TRD track which has to be extrapolated
-// 
-// Output
-//   number of clusters attached to the track
-//
-// Detailed description
-//
-// Starting from current radial position of track <t> this function
-// extrapolates the track through the 6 TRD layers. The following steps
-// are being performed for each plane:
-// 1. prepare track:
-//   a. get plane limits in the local x direction
-//   b. check crossing sectors 
-//   c. check track inclination
-// 2. build tracklet (see AliTRDseed::AttachClusters() for details)
-// 3. evaluate material budget using the geo manager
-// 4. propagate and update track using the tracklet information.
-//
-// Debug level 2
-//
-
-       Int_t nClustersExpected = 0;
-  // Loop through the TRD planes
-  for (Int_t iplane = 0; iplane < AliTRDgeometry::Nplan(); iplane++) {
-               //AliInfo(Form("Processing plane %d ...", iplane));
-               // Get the global time bin for the first local time bin of the given plane
-    Int_t row0 = GetGlobalTimeBin(0, iplane, fTimeBinsPerPlane-1);
-
-               // Retrive first propagation layer in the chamber
-               AliTRDpropagationLayer *layer = fTrSec[0]->GetLayer(row0);
-
-               // Get the X coordinates of the propagation layer for the first time bin
-    Double_t currentx = layer->GetX(); // what if X is not defined ???
-    if (currentx < t.GetX()) continue;
+  // Extrapolates the TRD track in the TOF direction.
+  //
+  // Parameters
+  //   t : the TRD track which has to be extrapolated
+  // 
+  // Output
+  //   number of clusters attached to the track
+  //
+  // Detailed description
+  //
+  // Starting from current radial position of track <t> this function
+  // extrapolates the track through the 6 TRD layers. The following steps
+  // are being performed for each plane:
+  // 1. prepare track:
+  //   a. get plane limits in the local x direction
+  //   b. check crossing sectors 
+  //   c. check track inclination
+  // 2. build tracklet (see AliTRDseed::AttachClusters() for details)
+  // 3. evaluate material budget using the geo manager
+  // 4. propagate and update track using the tracklet information.
+  //
+  // Debug level 2
+  //
+
+  Int_t nClustersExpected = 0;
+  Double_t clength = AliTRDgeometry::AmThick() + AliTRDgeometry::DrThick();
+  AliTRDtrackingChamber *chamber = 0x0;
+  
+  AliTRDseedV1 tracklet, *ptrTracklet = 0x0;
+  // in case of stand alone tracking we store all the pointers to the tracklets in a temporary array
+  AliTRDseedV1 *tracklets[kNPlanes];
+  memset(tracklets, 0, sizeof(AliTRDseedV1 *) * kNPlanes);
+  for(Int_t ip = 0; ip < kNPlanes; ip++){
+    tracklets[ip] = t.GetTracklet(ip);
+    t.UnsetTracklet(ip);
+  } 
+
+  // Loop through the TRD layers
+  for (Int_t ilayer = 0; ilayer < AliTRDgeometry::Nlayer(); ilayer++) {
+    // BUILD TRACKLET IF NOT ALREADY BUILT
+    Double_t x = 0., y, z, alpha;
+    ptrTracklet  = tracklets[ilayer];
+    if(!ptrTracklet){
+      ptrTracklet = new(&tracklet) AliTRDseedV1(ilayer);
+      ptrTracklet->SetReconstructor(fReconstructor);
+      alpha = t.GetAlpha();
+      Int_t sector = Int_t(alpha/AliTRDgeometry::GetAlpha() + (alpha>0. ? 0 : AliTRDgeometry::kNsector));
+
+      if(!fTrSec[sector].GetNChambers()) continue;
+      
+      if((x = fTrSec[sector].GetX(ilayer)) < 1.) continue;
+    
+      if (!t.GetProlongation(x, y, z)) return -1/*nClustersExpected*/;
+      Int_t stack = fGeom->GetStack(z, ilayer);
+      Int_t nCandidates = stack >= 0 ? 1 : 2;
+      z -= stack >= 0 ? 0. : 4.; 
+      
+      for(int icham=0; icham<nCandidates; icham++, z+=8){
+        if((stack = fGeom->GetStack(z, ilayer)) < 0) continue;
+      
+        if(!(chamber = fTrSec[sector].GetChamber(stack, ilayer))) continue;
+      
+        if(chamber->GetNClusters() < fgNTimeBins*fReconstructor->GetRecoParam() ->GetFindableClusters()) continue;
+      
+        x = chamber->GetX();
+      
+        AliTRDpadPlane *pp = fGeom->GetPadPlane(ilayer, stack);
+        tracklet.SetTilt(TMath::Tan(TMath::DegToRad()*pp->GetTiltingAngle()));
+        tracklet.SetPadLength(pp->GetLengthIPad());
+        tracklet.SetDetector(chamber->GetDetector());
+        tracklet.SetX0(x);
+        if(!tracklet.Init(&t)){
+          t.SetStopped(kTRUE);
+          return nClustersExpected;
+        }
+        if(!tracklet.AttachClustersIter(chamber, 1000./*, kTRUE*/)) continue;
+        tracklet.Init(&t);
+        
+        if(tracklet.GetN() < fgNTimeBins*fReconstructor->GetRecoParam() ->GetFindableClusters()) continue;
+      
+        break;
+      }
+      //ptrTracklet->UseClusters();
+    }
+    if(!ptrTracklet->IsOK()){
+      if(x < 1.) continue; //temporary
+      if(!PropagateToX(t, x-fgkMaxStep, fgkMaxStep)) return -1/*nClustersExpected*/;
+      if(!AdjustSector(&t)) return -1/*nClustersExpected*/;
+      if(TMath::Abs(t.GetSnp()) > fgkMaxSnp) return -1/*nClustersExpected*/;
+      continue;
+    }
     
-               // Get the global time bin for the last local time bin of the given plane
-               Int_t row1 = GetGlobalTimeBin(0, iplane, 0);
+    // Propagate closer to the current chamber if neccessary 
+    x -= clength;
+    if (x > (fgkMaxStep + t.GetX()) && !PropagateToX(t, x-fgkMaxStep, fgkMaxStep)) return -1/*nClustersExpected*/;
+    if (!AdjustSector(&t)) return -1/*nClustersExpected*/;
+    if (TMath::Abs(t.GetSnp()) > fgkMaxSnp) return -1/*nClustersExpected*/;
     
-               // Propagate closer to the current chamber if neccessary 
-    if (currentx > (fgkMaxStep + t.GetX()) && !PropagateToX(t, currentx-fgkMaxStep, fgkMaxStep)) break;
-   
-               // Rotate track to adjacent sector if neccessary
-    if (!AdjustSector(&t)) break;
-               Int_t sector =  Int_t(TMath::Abs(t.GetAlpha()/AliTRDgeometry::GetAlpha()));
-               if(t.GetAlpha() < 0) sector = AliTRDgeometry::Nsect() - sector-1;
-               
-               //AliInfo(Form("sector %d [%f]", sector, t.GetAlpha()));
-
-               // Check whether azimuthal angle is getting too large
-    if (TMath::Abs(t.GetSnp()) > fgkMaxSnp) break;
-   
+    // load tracklet to the tracker and the track
+    ptrTracklet = SetTracklet(ptrTracklet);
+    t.SetTracklet(ptrTracklet, fTracklets->GetEntriesFast()-1);
+  
+  
+    // Calculate the mean material budget along the path inside the chamber
     //Calculate global entry and exit positions of the track in chamber (only track prolongation)
     Double_t xyz0[3]; // entry point 
-               t.GetXYZ(xyz0);   
-               //printf("Entry global x[%7.3f] y[%7.3f] z[%7.3f]\n", xyz0[0], xyz0[1], xyz0[2]);
-                               
-               // Get local Y and Z at the X-position of the end of the chamber
-               Double_t x0 = fTrSec[sector]->GetLayer(row1)->GetX(), y, z;
-               if (!t.GetProlongation(x0, y, z)) break;
-               //printf("Exit  local x[%7.3f] y[%7.3f] z[%7.3f]\n", x0, y, z);
-
-               Double_t xyz1[3]; // exit point
-               xyz1[0] =  x0 * TMath::Cos(t.GetAlpha()) - y * TMath::Sin(t.GetAlpha()); 
-    xyz1[1] = +x0 * TMath::Sin(t.GetAlpha()) + y * TMath::Cos(t.GetAlpha());
+    t.GetXYZ(xyz0);
+    alpha = t.GetAlpha();
+    x = ptrTracklet->GetX0();
+    if (!t.GetProlongation(x, y, z)) return -1/*nClustersExpected*/;
+    Double_t xyz1[3]; // exit point
+    xyz1[0] =  x * TMath::Cos(alpha) - y * TMath::Sin(alpha); 
+    xyz1[1] = +x * TMath::Sin(alpha) + y * TMath::Cos(alpha);
     xyz1[2] =  z;
-
-               //printf("Exit  global x[%7.3f] y[%7.3f] z[%7.3f]\n", xyz1[0], xyz1[1], xyz1[2]);
-               // Find tracklet along the path inside the chamber
-    AliTRDseedV1 tracklet(*t.GetTracklet(iplane));
-               // if the track is not already build (e.g. stand alone tracker) we build it now.
-               if(!tracklet.GetN()){ // a better check has to be implemented TODO!!!!!!!
-               
-                       //AliInfo(Form("Building tracklet for plane %d ...", iplane));
-                       // check if we are inside detection volume
-                       Int_t ichmb = fGeom->GetChamber(xyz0[2], iplane); 
-                       if(ichmb<0) ichmb = fGeom->GetChamber(xyz1[2], iplane);
-                       if(ichmb<0){
-                               // here we should decide what to do with the track. The space between the pads in 2 chambers is 4cm+. Is it making sense to continue building the tracklet here TODO????
-                               AliWarning(Form("Track prolongated in the interspace between TRD detectors in plane %d. Skip plane. To be fixed !", iplane));
-                               continue;
-                       }
-       
-                       // temporary until the functionalities of AliTRDpropagationLayer and AliTRDstackLayer are merged TODO
-                       AliTRDpadPlane *pp = fGeom->GetPadPlane(iplane, ichmb);
-                       Int_t nrows = pp->GetNrows();
-                       Double_t stacklength = pp->GetRow0ROC() - pp->GetRowEndROC();/*(nrows - 2) * pp->GetLengthIPad()        + 2 * pp->GetLengthOPad() + (nrows - 1) * pp->GetRowSpacing();*/
-                       Double_t z0  = fGeom->GetRow0(iplane, ichmb, 0);
-
-                       Int_t nClustersChmb = 0;
-                       AliTRDstackLayer stackLayer[35];
-                       for(int itb=0; itb<fTimeBinsPerPlane; itb++){
-                               const AliTRDpropagationLayer ksmLayer(*(fTrSec[sector]->GetLayer(row1 - itb)));
-                               stackLayer[itb] = ksmLayer;
-#ifdef DEBUG
-                               stackLayer[itb].SetDebugStream(fDebugStreamer);
-#endif                 
-                               stackLayer[itb].SetRange(z0 - stacklength, stacklength);
-                               stackLayer[itb].SetSector(sector);
-                               stackLayer[itb].SetStackNr(ichmb);
-                               stackLayer[itb].SetNRows(nrows);
-                               stackLayer[itb].SetRecoParam(fRecoParam);
-                               stackLayer[itb].BuildIndices();
-                               nClustersChmb += stackLayer[itb].GetNClusters();
-                       }
-                       if(!nClustersChmb) continue;
-                       //AliInfo(Form("Detector p[%d] c[%d]. Building tracklet from %d clusters ... ", iplane, ichmb, nClustersChmb));
-
-                       tracklet.SetRecoParam(fRecoParam);
-                       tracklet.SetTilt(TMath::Tan(-TMath::DegToRad()*pp->GetTiltingAngle()));
-                       tracklet.SetPadLength(pp->GetLengthIPad());
-                       tracklet.SetPlane(iplane);
-                       //Int_t tbRange   = fTimeBinsPerPlane; //Int_t(AliTRDgeometry::CamHght()+AliTRDgeometry::CdrHght() * AliTRDCommonParam::Instance()->GetSamplingFrequency()/AliTRDcalibDB::Instance()->GetVdriftDet()->GetValue(det));
-                       //printf("%d hl[%f] pl[%f] tb[%d]\n", il, hL[il], padlength[il], tbRange[il]);
-                       //tracklet.SetNTimeBinsRange(tbRange);
-                       tracklet.SetX0(x0);
-                       tracklet.Init(&t);
-                       if(!tracklet.AttachClustersIter(stackLayer, 1000.)) continue;
-                       tracklet.Init(&t);
-
-                       //if(!tracklet.AttachClusters(stackLayer, kTRUE)) continue;
-                       //if(!tracklet.Fit()) continue;
-               }
-               Int_t ncl = tracklet.GetN();
-               //AliInfo(Form("N clusters %d", ncl));
-               
-               // Discard tracklet if bad quality.
-               //Check if this condition is not already checked during building of the tracklet
-    if(ncl < fTimeBinsPerPlane * fRecoParam->GetFindableClusters()){
-                       //AliInfo(Form("Discard tracklet for %d nclusters", ncl));
-                       continue;
-               }
-               
-               // load tracklet to the tracker and the track
-               Int_t index = SetTracklet(&tracklet);
-               t.SetTracklet(&tracklet, iplane, index);
-               
-               // Calculate the mean material budget along the path inside the chamber
     Double_t param[7];
-               AliTracker::MeanMaterialBudget(xyz0, xyz1, param);      
+    if(AliTracker::MeanMaterialBudget(xyz0, xyz1, param)<=0.) return -1;       
     // The mean propagation parameters
     Double_t xrho = param[0]*param[4]; // density*length
     Double_t xx0  = param[1]; // radiation length
-               
-               // Propagate and update track
-               t.PropagateTo(tracklet.GetX0(), xx0, xrho);
-         if (!AdjustSector(&t)) break;
-               Double_t maxChi2 = t.GetPredictedChi2(&tracklet);
-               if (maxChi2<1e+10 && t.Update(&tracklet, maxChi2)){ 
-                       nClustersExpected += ncl;
-               }
-               // Reset material budget if 2 consecutive gold
-               if(iplane>0 && ncl + t.GetTracklet(iplane-1)->GetN() > 20) t.SetBudget(2, 0.);
-
-               // Make backup of the track until is gold
-               // TO DO update quality check of the track.
-               // consider comparison with fTimeBinsRange
-               Float_t ratio0 = ncl / Float_t(fTimeBinsPerPlane);
-               //Float_t ratio1 = Float_t(t.GetNumberOfClusters()+1) / Float_t(t.GetNExpected()+1);    
+    
+    // Propagate and update track
+    if (!t.PropagateTo(x, xx0, xrho)) return -1/*nClustersExpected*/;
+    if (!AdjustSector(&t)) return -1/*nClustersExpected*/;
+    Double_t maxChi2 = t.GetPredictedChi2(ptrTracklet);
+    if (!t.Update(ptrTracklet, maxChi2)) return -1/*nClustersExpected*/;
+    if (maxChi2<1e+10) { 
+      nClustersExpected += ptrTracklet->GetN();
+      //t.SetTracklet(&tracklet, index);
+    }
+    // Reset material budget if 2 consecutive gold
+    if(ilayer>0 && t.GetTracklet(ilayer-1) && ptrTracklet->GetN() + t.GetTracklet(ilayer-1)->GetN() > 20) t.SetBudget(2, 0.);
+
+    // Make backup of the track until is gold
+    // TO DO update quality check of the track.
+    // consider comparison with fTimeBinsRange
+    Float_t ratio0 = ptrTracklet->GetN() / Float_t(fgNTimeBins);
+    //Float_t ratio1 = Float_t(t.GetNumberOfClusters()+1) / Float_t(t.GetNExpected()+1);       
     //printf("tracklet.GetChi2() %f     [< 18.0]\n", tracklet.GetChi2()); 
-               //printf("ratio0    %f              [>   0.8]\n", ratio0);
-               //printf("ratio1     %f             [>   0.6]\n", ratio1); 
-               //printf("ratio0+ratio1 %f          [>   1.5]\n", ratio0+ratio1); 
-               //printf("t.GetNCross()  %d         [==    0]\n", t.GetNCross()); 
-               //printf("TMath::Abs(t.GetSnp()) %f [<  0.85]\n", TMath::Abs(t.GetSnp()));
-               //printf("t.GetNumberOfClusters() %d [>    20]\n", t.GetNumberOfClusters());
+    //printf("ratio0    %f              [>   0.8]\n", ratio0);
+    //printf("ratio1     %f             [>   0.6]\n", ratio1); 
+    //printf("ratio0+ratio1 %f          [>   1.5]\n", ratio0+ratio1); 
+    //printf("t.GetNCross()  %d         [==    0]\n", t.GetNCross()); 
+    //printf("TMath::Abs(t.GetSnp()) %f [<  0.85]\n", TMath::Abs(t.GetSnp()));
+    //printf("t.GetNumberOfClusters() %d [>    20]\n", t.GetNumberOfClusters());
     
-               if (//(tracklet.GetChi2()      <  18.0) && TO DO check with FindClusters and move it to AliTRDseed::Update 
+    if (//(tracklet.GetChi2()      <  18.0) && TO DO check with FindClusters and move it to AliTRDseed::Update 
         (ratio0                  >   0.8) && 
         //(ratio1                  >   0.6) && 
         //(ratio0+ratio1           >   1.5) && 
         (t.GetNCross()           ==    0) && 
         (TMath::Abs(t.GetSnp())  <  0.85) &&
         (t.GetNumberOfClusters() >    20)) t.MakeBackupTrack();
-               
-       } // end planes loop
+    
+  } // end layers loop
+
+  if(fReconstructor->GetStreamLevel(AliTRDReconstructor::kTracker) > 1){
+    TTreeSRedirector &cstreamer = *fgDebugStreamer;
+    Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
+    //AliTRDtrackV1 *debugTrack = new AliTRDtrackV1(t);
+    //debugTrack->SetOwner();
+    cstreamer << "FollowBackProlongation"
+        << "EventNumber="                      << eventNumber
+        << "ncl="                                                      << nClustersExpected
+        //<< "track.="                                 << debugTrack
+        << "\n";
+  }
+  
+  return nClustersExpected;
+}
+
+//_________________________________________________________________________
+Float_t AliTRDtrackerV1::FitRieman(AliTRDseedV1 *tracklets, Double_t *chi2, Int_t *planes){
+  //
+  // Fits a Riemann-circle to the given points without tilting pad correction.
+  // The fit is performed using an instance of the class AliRieman (equations 
+  // and transformations see documentation of this class)
+  // Afterwards all the tracklets are Updated
+  //
+  // Parameters: - Array of tracklets (AliTRDseedV1)
+  //             - Storage for the chi2 values (beginning with direction z)  
+  //             - Seeding configuration
+  // Output:     - The curvature
+  //
+  AliRieman *fitter = AliTRDtrackerV1::GetRiemanFitter();
+  fitter->Reset();
+  Int_t allplanes[] = {0, 1, 2, 3, 4, 5};
+  Int_t *ppl = &allplanes[0];
+  Int_t maxLayers = 6;
+  if(planes){
+    maxLayers = 4;
+    ppl = planes;
+  }
+  for(Int_t il = 0; il < maxLayers; il++){
+    if(!tracklets[ppl[il]].IsOK()) continue;
+    fitter->AddPoint(tracklets[ppl[il]].GetX0(), tracklets[ppl[il]].GetYfitR(0), tracklets[ppl[il]].GetZProb(),1,10);
+  }
+  fitter->Update();
+  // Set the reference position of the fit and calculate the chi2 values
+  memset(chi2, 0, sizeof(Double_t) * 2);
+  for(Int_t il = 0; il < maxLayers; il++){
+    // Reference positions
+    tracklets[ppl[il]].Init(fitter);
+    
+    // chi2
+    if((!tracklets[ppl[il]].IsOK()) && (!planes)) continue;
+    chi2[0] += tracklets[ppl[il]].GetChi2Y();
+    chi2[1] += tracklets[ppl[il]].GetChi2Z();
+  }
+  return fitter->GetC();
+}
+
+//_________________________________________________________________________
+void AliTRDtrackerV1::FitRieman(AliTRDcluster **seedcl, Double_t chi2[2])
+{
+  //
+  // Performs a Riemann helix fit using the seedclusters as spacepoints
+  // Afterwards the chi2 values are calculated and the seeds are updated
+  //
+  // Parameters: - The four seedclusters
+  //             - The tracklet array (AliTRDseedV1)
+  //             - The seeding configuration
+  //             - Chi2 array
+  //
+  // debug level 2
+  //
+  AliRieman *fitter = AliTRDtrackerV1::GetRiemanFitter();
+  fitter->Reset();
+  for(Int_t i = 0; i < 4; i++)
+    fitter->AddPoint(seedcl[i]->GetX(), seedcl[i]->GetY(), seedcl[i]->GetZ(), 1, 10);
+  fitter->Update();
+  
+  
+  // Update the seed and calculated the chi2 value
+  chi2[0] = 0; chi2[1] = 0;
+  for(Int_t ipl = 0; ipl < kNSeedPlanes; ipl++){
+    // chi2
+    chi2[0] += (seedcl[ipl]->GetZ() - fitter->GetZat(seedcl[ipl]->GetX())) * (seedcl[ipl]->GetZ() - fitter->GetZat(seedcl[ipl]->GetX()));
+    chi2[1] += (seedcl[ipl]->GetY() - fitter->GetYat(seedcl[ipl]->GetX())) * (seedcl[ipl]->GetY() - fitter->GetYat(seedcl[ipl]->GetX()));
+  }    
+}
+
+
+//_________________________________________________________________________
+Float_t AliTRDtrackerV1::FitTiltedRiemanConstraint(AliTRDseedV1 *tracklets, Double_t zVertex)
+{
+  //
+  // Fits a helix to the clusters. Pad tilting is considered. As constraint it is 
+  // assumed that the vertex position is set to 0.
+  // This method is very usefull for high-pt particles
+  // Basis for the fit: (x - x0)^2 + (y - y0)^2 - R^2 = 0
+  //      x0, y0: Center of the circle
+  // Measured y-position: ymeas = y - tan(phiT)(zc - zt)
+  //      zc: center of the pad row
+  // Equation which has to be fitted (after transformation):
+  // a + b * u + e * v + 2*(ymeas + tan(phiT)(z - zVertex))*t = 0
+  // Transformation:
+  // t = 1/(x^2 + y^2)
+  // u = 2 * x * t
+  // v = 2 * x * tan(phiT) * t
+  // Parameters in the equation: 
+  //    a = -1/y0, b = x0/y0, e = dz/dx
+  //
+  // The Curvature is calculated by the following equation:
+  //               - curv = a/Sqrt(b^2 + 1) = 1/R
+  // Parameters:   - the 6 tracklets
+  //               - the Vertex constraint
+  // Output:       - the Chi2 value of the track
+  //
+  // debug level 5
+  //
+
+  TLinearFitter *fitter = GetTiltedRiemanFitterConstraint();
+  fitter->StoreData(kTRUE);
+  fitter->ClearPoints();
+  AliTRDcluster *cl = 0x0;
+  
+  Float_t x, y, z, w, t, error, tilt;
+  Double_t uvt[2];
+  Int_t nPoints = 0;
+  for(Int_t ilr = 0; ilr < AliTRDgeometry::kNlayer; ilr++){
+    if(!tracklets[ilr].IsOK()) continue;
+    for(Int_t itb = 0; itb < fgNTimeBins; itb++){
+      if(!tracklets[ilr].IsUsable(itb)) continue;
+      cl = tracklets[ilr].GetClusters(itb);
+      x = cl->GetX();
+      y = cl->GetY();
+      z = cl->GetZ();
+      tilt = tracklets[ilr].GetTilt();
+      // Transformation
+      t = 1./(x * x + y * y);
+      uvt[0] = 2. * x * t;
+      uvt[1] = 2. * x * t * tilt ;
+      w = 2. * (y + tilt * (z - zVertex)) * t;
+      error = 2. * 0.2 * t;
+      fitter->AddPoint(uvt, w, error);
+      nPoints++;
+    }
+  }
+  fitter->Eval();
+
+  // Calculate curvature
+  Double_t a = fitter->GetParameter(0);
+  Double_t b = fitter->GetParameter(1);
+  Double_t curvature = a/TMath::Sqrt(b*b + 1);
+
+  Float_t chi2track = fitter->GetChisquare()/Double_t(nPoints);
+  for(Int_t ip = 0; ip < AliTRDtrackerV1::kNPlanes; ip++)
+    tracklets[ip].SetCC(curvature);
+
+/*  if(fReconstructor->GetStreamLevel() >= 5){
+    //Linear Model on z-direction
+    Double_t xref = CalculateReferenceX(tracklets);            // Relative to the middle of the stack
+    Double_t slope = fitter->GetParameter(2);
+    Double_t zref = slope * xref;
+    Float_t chi2Z = CalculateChi2Z(tracklets, zref, slope, xref);
+    Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
+    Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
+    TTreeSRedirector &treeStreamer = *fgDebugStreamer;
+    treeStreamer << "FitTiltedRiemanConstraint"
+    << "EventNumber="          << eventNumber
+    << "CandidateNumber="      << candidateNumber
+    << "Curvature="                            << curvature
+    << "Chi2Track="                            << chi2track
+    << "Chi2Z="                                                << chi2Z
+    << "zref="                                         << zref
+    << "\n";
+  }*/
+  return chi2track;
+}
+
+//_________________________________________________________________________
+Float_t AliTRDtrackerV1::FitTiltedRieman(AliTRDseedV1 *tracklets, Bool_t sigError)
+{
+  //
+  // Performs a Riemann fit taking tilting pad correction into account
+  // The equation of a Riemann circle, where the y position is substituted by the 
+  // measured y-position taking pad tilting into account, has to be transformed
+  // into a 4-dimensional hyperplane equation
+  // Riemann circle: (x-x0)^2 + (y-y0)^2 -R^2 = 0
+  // Measured y-Position: ymeas = y - tan(phiT)(zc - zt)
+  //          zc: center of the pad row
+  //          zt: z-position of the track
+  // The z-position of the track is assumed to be linear dependent on the x-position
+  // Transformed equation: a + b * u + c * t + d * v  + e * w - 2 * (ymeas + tan(phiT) * zc) * t = 0
+  // Transformation:       u = 2 * x * t
+  //                       v = 2 * tan(phiT) * t
+  //                       w = 2 * tan(phiT) * (x - xref) * t
+  //                       t = 1 / (x^2 + ymeas^2)
+  // Parameters:           a = -1/y0
+  //                       b = x0/y0
+  //                       c = (R^2 -x0^2 - y0^2)/y0
+  //                       d = offset
+  //                       e = dz/dx
+  // If the offset respectively the slope in z-position is impossible, the parameters are fixed using 
+  // results from the simple riemann fit. Afterwards the fit is redone.
+  // The curvature is calculated according to the formula:
+  //                       curv = a/(1 + b^2 + c*a) = 1/R
+  //
+  // Paramters:   - Array of tracklets (connected to the track candidate)
+  //              - Flag selecting the error definition
+  // Output:      - Chi2 values of the track (in Parameter list)
+  //
+  TLinearFitter *fitter = GetTiltedRiemanFitter();
+  fitter->StoreData(kTRUE);
+  fitter->ClearPoints();
+  AliTRDLeastSquare zfitter;
+  AliTRDcluster *cl = 0x0;
+
+  Double_t xref = CalculateReferenceX(tracklets);
+  Double_t x, y, z, t, tilt, dx, w, we;
+  Double_t uvt[4];
+  Int_t nPoints = 0;
+  // Containers for Least-square fitter
+  for(Int_t ipl = 0; ipl < kNPlanes; ipl++){
+    if(!tracklets[ipl].IsOK()) continue;
+    for(Int_t itb = 0; itb < fgNTimeBins; itb++){
+      if(!(cl = tracklets[ipl].GetClusters(itb))) continue;
+      if (!tracklets[ipl].IsUsable(itb)) continue;
+      x = cl->GetX();
+      y = cl->GetY();
+      z = cl->GetZ();
+      tilt = tracklets[ipl].GetTilt();
+      dx = x - xref;
+      // Transformation
+      t = 1./(x*x + y*y);
+      uvt[0] = 2. * x * t;
+      uvt[1] = t;
+      uvt[2] = 2. * tilt * t;
+      uvt[3] = 2. * tilt * dx * t;
+      w = 2. * (y + tilt*z) * t;
+      // error definition changes for the different calls
+      we = 2. * t;
+      we *= sigError ? tracklets[ipl].GetSigmaY() : 0.2;
+      fitter->AddPoint(uvt, w, we);
+      zfitter.AddPoint(&x, z, static_cast<Double_t>(TMath::Sqrt(cl->GetSigmaZ2())));
+      nPoints++;
+    }
+  }
+  fitter->Eval();
+  zfitter.Eval();
+
+  Double_t offset = fitter->GetParameter(3);
+  Double_t slope  = fitter->GetParameter(4);
+
+  // Linear fitter  - not possible to make boundaries
+  // Do not accept non possible z and dzdx combinations
+  Bool_t acceptablez = kTRUE;
+  Double_t zref = 0.0;
+  for (Int_t iLayer = 0; iLayer < kNPlanes; iLayer++) {
+    if(!tracklets[iLayer].IsOK()) continue;
+    zref = offset + slope * (tracklets[iLayer].GetX0() - xref);
+    if (TMath::Abs(tracklets[iLayer].GetZProb() - zref) > tracklets[iLayer].GetPadLength() * 0.5 + 1.0) 
+      acceptablez = kFALSE;
+  }
+  if (!acceptablez) {
+    Double_t dzmf      = zfitter.GetFunctionParameter(1);
+    Double_t zmf       = zfitter.GetFunctionValue(&xref);
+    fgTiltedRieman->FixParameter(3, zmf);
+    fgTiltedRieman->FixParameter(4, dzmf);
+    fitter->Eval();
+    fitter->ReleaseParameter(3);
+    fitter->ReleaseParameter(4);
+    offset = fitter->GetParameter(3);
+    slope = fitter->GetParameter(4);
+  }
+
+  // Calculate Curvarture
+  Double_t a     =  fitter->GetParameter(0);
+  Double_t b     =  fitter->GetParameter(1);
+  Double_t c     =  fitter->GetParameter(2);
+  Double_t curvature =  1.0 + b*b - c*a;
+  if (curvature > 0.0) 
+    curvature  =  a / TMath::Sqrt(curvature);
+
+  Double_t chi2track = fitter->GetChisquare()/Double_t(nPoints);
+
+  // Update the tracklets
+  Double_t dy, dz;
+  for(Int_t iLayer = 0; iLayer < AliTRDtrackerV1::kNPlanes; iLayer++) {
+
+    x  = tracklets[iLayer].GetX0();
+    y  = 0;
+    z  = 0;
+    dy = 0;
+    dz = 0;
+
+    // y:     R^2 = (x - x0)^2 + (y - y0)^2
+    //     =>   y = y0 +/- Sqrt(R^2 - (x - x0)^2)
+    //          R = Sqrt() = 1/Curvature
+    //     =>   y = y0 +/- Sqrt(1/Curvature^2 - (x - x0)^2)  
+    Double_t res = (x * a + b);                                                                // = (x - x0)/y0
+    res *= res;
+    res  = 1.0 - c * a + b * b - res;                                  // = (R^2 - (x - x0)^2)/y0^2
+    if (res >= 0) {
+      res = TMath::Sqrt(res);
+      y    = (1.0 - res) / a;
+    }
+
+    // dy:      R^2 = (x - x0)^2 + (y - y0)^2
+    //     =>     y = +/- Sqrt(R^2 - (x - x0)^2) + y0
+    //     => dy/dx = (x - x0)/Sqrt(R^2 - (x - x0)^2) 
+    // Curvature: cr = 1/R = a/Sqrt(1 + b^2 - c*a)
+    //     => dy/dx =  (x - x0)/(1/(cr^2) - (x - x0)^2) 
+    Double_t x0 = -b / a;
+    if (-c * a + b * b + 1 > 0) {
+      if (1.0/(curvature * curvature) - (x - x0) * (x - x0) > 0.0) {
+  Double_t yderiv = (x - x0) / TMath::Sqrt(1.0/(curvature * curvature) - (x - x0) * (x - x0));
+  if (a < 0) yderiv *= -1.0;
+  dy = yderiv;
+      }
+    }
+    z  = offset + slope * (x - xref);
+    dz = slope;
+    tracklets[iLayer].SetYref(0, y);
+    tracklets[iLayer].SetYref(1, dy);
+    tracklets[iLayer].SetZref(0, z);
+    tracklets[iLayer].SetZref(1, dz);
+    tracklets[iLayer].SetC(curvature);
+    tracklets[iLayer].SetChi2(chi2track);
+  }
+  
+/*  if(fReconstructor->GetStreamLevel() >=5){
+    TTreeSRedirector &cstreamer = *fgDebugStreamer;
+    Int_t eventNumber                  = AliTRDtrackerDebug::GetEventNumber();
+    Int_t candidateNumber      = AliTRDtrackerDebug::GetCandidateNumber();
+    Double_t chi2z = CalculateChi2Z(tracklets, offset, slope, xref);
+    cstreamer << "FitTiltedRieman0"
+        << "EventNumber="                      << eventNumber
+        << "CandidateNumber="  << candidateNumber
+        << "xref="                                             << xref
+        << "Chi2Z="                                            << chi2z
+        << "\n";
+  }*/
+  return chi2track;
+}
+
+
+//____________________________________________________________________
+Double_t AliTRDtrackerV1::FitLine(AliTRDtrackV1 *track, AliTRDseedV1 *tracklets, Bool_t err, Int_t np, AliTrackPoint *points)
+{
+  AliTRDLeastSquare yfitter, zfitter;
+  AliTRDcluster *cl = 0x0;
+
+  AliTRDseedV1 work[kNPlanes], *tracklet = 0x0;
+  if(!tracklets){
+    for(Int_t ipl = 0; ipl < kNPlanes; ipl++){
+      if(!(tracklet = track->GetTracklet(ipl))) continue;
+      if(!tracklet->IsOK()) continue;
+      new(&work[ipl]) AliTRDseedV1(*tracklet);
+    }
+    tracklets = &work[0];
+  }
+
+  Double_t xref = CalculateReferenceX(tracklets);
+  Double_t x, y, z, dx, ye, yr, tilt;
+  for(Int_t ipl = 0; ipl < kNPlanes; ipl++){
+    if(!tracklets[ipl].IsOK()) continue;
+    for(Int_t itb = 0; itb < fgNTimeBins; itb++){
+      if(!(cl = tracklets[ipl].GetClusters(itb))) continue;
+      if (!tracklets[ipl].IsUsable(itb)) continue;
+      x = cl->GetX();
+      z = cl->GetZ();
+      dx = x - xref;
+      zfitter.AddPoint(&dx, z, static_cast<Double_t>(TMath::Sqrt(cl->GetSigmaZ2())));
+    }
+  }
+  zfitter.Eval();
+  Double_t z0    = zfitter.GetFunctionParameter(0);
+  Double_t dzdx  = zfitter.GetFunctionParameter(1);
+  for(Int_t ipl = 0; ipl < kNPlanes; ipl++){
+    if(!tracklets[ipl].IsOK()) continue;
+    for(Int_t itb = 0; itb < fgNTimeBins; itb++){
+      if(!(cl = tracklets[ipl].GetClusters(itb))) continue;
+      if (!tracklets[ipl].IsUsable(itb)) continue;
+      x = cl->GetX();
+      y = cl->GetY();
+      z = cl->GetZ();
+      tilt = tracklets[ipl].GetTilt();
+      dx = x - xref;
+      yr = y + tilt*(z - z0 - dzdx*dx); 
+      // error definition changes for the different calls
+      ye = tilt*TMath::Sqrt(cl->GetSigmaZ2());
+      ye += err ? tracklets[ipl].GetSigmaY() : 0.2;
+      yfitter.AddPoint(&dx, yr, ye);
+    }
+  }
+  yfitter.Eval();
+  Double_t y0   = yfitter.GetFunctionParameter(0);
+  Double_t dydx = yfitter.GetFunctionParameter(1);
+  Double_t chi2 = 0.;//yfitter.GetChisquare()/Double_t(nPoints);
+
+  //update track points array
+  if(np && points){
+    Float_t xyz[3];
+    for(int ip=0; ip<np; ip++){
+      points[ip].GetXYZ(xyz);
+      xyz[1] = y0 + dydx * (xyz[0] - xref);
+      xyz[2] = z0 + dzdx * (xyz[0] - xref);
+      points[ip].SetXYZ(xyz);
+    }
+  }
+  return chi2;
+}
+
+
+//_________________________________________________________________________
+Double_t AliTRDtrackerV1::FitRiemanTilt(AliTRDtrackV1 *track, AliTRDseedV1 *tracklets, Bool_t sigError, Int_t np, AliTrackPoint *points)
+{
+  //
+  // Performs a Riemann fit taking tilting pad correction into account
+  // The equation of a Riemann circle, where the y position is substituted by the 
+  // measured y-position taking pad tilting into account, has to be transformed
+  // into a 4-dimensional hyperplane equation
+  // Riemann circle: (x-x0)^2 + (y-y0)^2 -R^2 = 0
+  // Measured y-Position: ymeas = y - tan(phiT)(zc - zt)
+  //          zc: center of the pad row
+  //          zt: z-position of the track
+  // The z-position of the track is assumed to be linear dependent on the x-position
+  // Transformed equation: a + b * u + c * t + d * v  + e * w - 2 * (ymeas + tan(phiT) * zc) * t = 0
+  // Transformation:       u = 2 * x * t
+  //                       v = 2 * tan(phiT) * t
+  //                       w = 2 * tan(phiT) * (x - xref) * t
+  //                       t = 1 / (x^2 + ymeas^2)
+  // Parameters:           a = -1/y0
+  //                       b = x0/y0
+  //                       c = (R^2 -x0^2 - y0^2)/y0
+  //                       d = offset
+  //                       e = dz/dx
+  // If the offset respectively the slope in z-position is impossible, the parameters are fixed using 
+  // results from the simple riemann fit. Afterwards the fit is redone.
+  // The curvature is calculated according to the formula:
+  //                       curv = a/(1 + b^2 + c*a) = 1/R
+  //
+  // Paramters:   - Array of tracklets (connected to the track candidate)
+  //              - Flag selecting the error definition
+  // Output:      - Chi2 values of the track (in Parameter list)
+  //
+  TLinearFitter *fitter = GetTiltedRiemanFitter();
+  fitter->StoreData(kTRUE);
+  fitter->ClearPoints();
+  AliTRDLeastSquare zfitter;
+  AliTRDcluster *cl = 0x0;
+
+  AliTRDseedV1 work[kNPlanes], *tracklet = 0x0;
+  if(!tracklets){
+    for(Int_t ipl = 0; ipl < kNPlanes; ipl++){
+      if(!(tracklet = track->GetTracklet(ipl))) continue;
+      if(!tracklet->IsOK()) continue;
+      new(&work[ipl]) AliTRDseedV1(*tracklet);
+    }
+    tracklets = &work[0];
+  }
+
+  Double_t xref = CalculateReferenceX(tracklets);
+  Double_t x, y, z, t, tilt, dx, w, we;
+  Double_t uvt[4];
+  Int_t nPoints = 0;
+  // Containers for Least-square fitter
+  for(Int_t ipl = 0; ipl < kNPlanes; ipl++){
+    if(!tracklets[ipl].IsOK()) continue;
+    for(Int_t itb = 0; itb < fgNTimeBins; itb++){
+      if(!(cl = tracklets[ipl].GetClusters(itb))) continue;
+      if (!tracklets[ipl].IsUsable(itb)) continue;
+      x = cl->GetX();
+      y = cl->GetY();
+      z = cl->GetZ();
+      tilt = tracklets[ipl].GetTilt();
+      dx = x - xref;
+      // Transformation
+      t = 1./(x*x + y*y);
+      uvt[0] = 2. * x * t;
+      uvt[1] = t;
+      uvt[2] = 2. * tilt * t;
+      uvt[3] = 2. * tilt * dx * t;
+      w = 2. * (y + tilt*z) * t;
+      // error definition changes for the different calls
+      we = 2. * t;
+      we *= sigError ? tracklets[ipl].GetSigmaY() : 0.2;
+      fitter->AddPoint(uvt, w, we);
+      zfitter.AddPoint(&x, z, static_cast<Double_t>(TMath::Sqrt(cl->GetSigmaZ2())));
+      nPoints++;
+    }
+  }
+  if(fitter->Eval()) return 1.E10;
+
+  Double_t z0    = fitter->GetParameter(3);
+  Double_t dzdx  = fitter->GetParameter(4);
+
+
+  // Linear fitter  - not possible to make boundaries
+  // Do not accept non possible z and dzdx combinations
+  Bool_t accept = kTRUE;
+  Double_t zref = 0.0;
+  for (Int_t iLayer = 0; iLayer < kNPlanes; iLayer++) {
+    if(!tracklets[iLayer].IsOK()) continue;
+    zref = z0 + dzdx * (tracklets[iLayer].GetX0() - xref);
+    if (TMath::Abs(tracklets[iLayer].GetZProb() - zref) > tracklets[iLayer].GetPadLength() * 0.5 + 1.0) 
+      accept = kFALSE;
+  }
+  if (!accept) {
+    zfitter.Eval();
+    Double_t dzmf      = zfitter.GetFunctionParameter(1);
+    Double_t zmf       = zfitter.GetFunctionValue(&xref);
+    fitter->FixParameter(3, zmf);
+    fitter->FixParameter(4, dzmf);
+    fitter->Eval();
+    fitter->ReleaseParameter(3);
+    fitter->ReleaseParameter(4);
+    z0   = fitter->GetParameter(3); // = zmf ?
+    dzdx = fitter->GetParameter(4); // = dzmf ?
+  }
+
+  // Calculate Curvature
+  Double_t a    =  fitter->GetParameter(0);
+  Double_t b    =  fitter->GetParameter(1);
+  Double_t c    =  fitter->GetParameter(2);
+  Double_t y0   = 1. / a;
+  Double_t x0   = -b * y0;
+  Double_t tmp  = y0*y0 + x0*x0 - c*y0;
+  if(tmp<=0.) return 1.E10;
+  Double_t R    = TMath::Sqrt(tmp);
+  Double_t C    =  1.0 + b*b - c*a;
+  if (C > 0.0) C  =  a / TMath::Sqrt(C);
+
+  // Calculate chi2 of the fit 
+  Double_t chi2 = fitter->GetChisquare()/Double_t(nPoints);
+
+  // Update the tracklets
+  if(!track){
+    for(Int_t ip = 0; ip < kNPlanes; ip++) {
+      x = tracklets[ip].GetX0();
+      tmp = R*R-(x-x0)*(x-x0);  
+      if(tmp <= 0.) continue;
+      tmp = TMath::Sqrt(tmp);  
+
+      // y:     R^2 = (x - x0)^2 + (y - y0)^2
+      //     =>   y = y0 +/- Sqrt(R^2 - (x - x0)^2)
+      tracklets[ip].SetYref(0, y0 - (y0>0.?1.:-1)*tmp);
+      //     => dy/dx = (x - x0)/Sqrt(R^2 - (x - x0)^2) 
+      tracklets[ip].SetYref(1, (x - x0) / tmp);
+      tracklets[ip].SetZref(0, z0 + dzdx * (x - xref));
+      tracklets[ip].SetZref(1, dzdx);
+      tracklets[ip].SetC(C);
+      tracklets[ip].SetChi2(chi2);
+    }
+  }
+
+  //update track points array
+  if(np && points){
+    Float_t xyz[3];
+    for(int ip=0; ip<np; ip++){
+      points[ip].GetXYZ(xyz);
+      xyz[1] = y0 - (y0>0.?1.:-1.)*TMath::Sqrt(R*R-(xyz[0]-x0)*(xyz[0]-x0));
+      xyz[2] = z0 + dzdx * (xyz[0] - xref);
+      points[ip].SetXYZ(xyz);
+    }
+  }
+  
+  return chi2;
+}
+
+
+//____________________________________________________________________
+Double_t AliTRDtrackerV1::FitKalman(AliTRDtrackV1 *track, AliTRDseedV1 *tracklets, Bool_t up, Int_t np, AliTrackPoint *points)
+{
+//   Kalman filter implementation for the TRD.
+//   It returns the positions of the fit in the array "points"
+// 
+//   Author : A.Bercuci@gsi.de
 
-#ifdef DEBUG
-       if(AliTRDReconstructor::StreamLevel() > 1){
-               TTreeSRedirector &cstreamer = *fDebugStreamer;
-               cstreamer << "FollowBackProlongation"
-                       << "ncl="      << nClustersExpected
-                       << "track.="   << &t
-                       << "\n";
-       }
-#endif
+  //printf("Start track @ x[%f]\n", track->GetX());
        
-       return nClustersExpected;
+  //prepare marker points along the track
+  Int_t ip = np ? 0 : 1;
+  while(ip<np){
+    if((up?-1:1) * (track->GetX() - points[ip].GetX()) > 0.) break;
+    //printf("AliTRDtrackerV1::FitKalman() : Skip track marker x[%d] = %7.3f. Before track start ( %7.3f ).\n", ip, points[ip].GetX(), track->GetX());
+    ip++;
+  }
+  //if(points) printf("First marker point @ x[%d] = %f\n", ip, points[ip].GetX());
+
+
+  AliTRDseedV1 tracklet, *ptrTracklet = 0x0;
+
+  //Loop through the TRD planes
+  for (Int_t jplane = 0; jplane < kNPlanes; jplane++) {
+    // GET TRACKLET OR BUILT IT                
+    Int_t iplane = up ? jplane : kNPlanes - 1 - jplane;
+    if(tracklets){ 
+      if(!(ptrTracklet = &tracklets[iplane])) continue;
+    }else{
+      if(!(ptrTracklet  = track->GetTracklet(iplane))){ 
+      /*AliTRDtrackerV1 *tracker = 0x0;
+        if(!(tracker = dynamic_cast<AliTRDtrackerV1*>( AliTRDReconstructor::Tracker()))) continue;
+        ptrTracklet = new(&tracklet) AliTRDseedV1(iplane);
+        if(!tracker->MakeTracklet(ptrTracklet, track)) */
+        continue;
+      }
+    }
+    if(!ptrTracklet->IsOK()) continue;
+
+    Double_t x = ptrTracklet->GetX0();
+
+    while(ip < np){
+      //don't do anything if next marker is after next update point.
+      if((up?-1:1) * (points[ip].GetX() - x) - fgkMaxStep < 0) break;
+
+      //printf("Propagate to x[%d] = %f\n", ip, points[ip].GetX());
+
+      if(((up?-1:1) * (points[ip].GetX() - track->GetX()) < 0) && !PropagateToX(*track, points[ip].GetX(), fgkMaxStep)) return -1.;
+      
+      Double_t xyz[3]; // should also get the covariance
+      track->GetXYZ(xyz); points[ip].SetXYZ(xyz[0], xyz[1], xyz[2]);
+      ip++;
+    }
+    //printf("plane[%d] tracklet[%p] x[%f]\n", iplane, ptrTracklet, x);
+
+    //Propagate closer to the next update point 
+    if(((up?-1:1) * (x - track->GetX()) + fgkMaxStep < 0) && !PropagateToX(*track, x + (up?-1:1)*fgkMaxStep, fgkMaxStep)) return -1.;
+
+    if(!AdjustSector(track)) return -1;
+    if(TMath::Abs(track->GetSnp()) > fgkMaxSnp) return -1;
+    
+    //load tracklet to the tracker and the track
+/*    Int_t index;
+    if((index = FindTracklet(ptrTracklet)) < 0){
+      ptrTracklet = SetTracklet(&tracklet);
+      index = fTracklets->GetEntriesFast()-1;
+    }
+    track->SetTracklet(ptrTracklet, index);*/
+
+
+    // register tracklet to track with tracklet creation !!
+    // PropagateBack : loaded tracklet to the tracker and update index 
+    // RefitInward : update index 
+    // MakeTrack   : loaded tracklet to the tracker and update index 
+    if(!tracklets) track->SetTracklet(ptrTracklet, -1);
+    
+  
+    //Calculate the mean material budget along the path inside the chamber
+    Double_t xyz0[3]; track->GetXYZ(xyz0);
+    Double_t alpha = track->GetAlpha();
+    Double_t xyz1[3], y, z;
+    if(!track->GetProlongation(x, y, z)) return -1;
+    xyz1[0] =  x * TMath::Cos(alpha) - y * TMath::Sin(alpha); 
+    xyz1[1] = +x * TMath::Sin(alpha) + y * TMath::Cos(alpha);
+    xyz1[2] =  z;
+    Double_t param[7];
+    if(AliTracker::MeanMaterialBudget(xyz0, xyz1, param)<=0.) break;   
+    Double_t xrho = param[0]*param[4]; // density*length
+    Double_t xx0  = param[1]; // radiation length
+    
+    //Propagate the track
+    track->PropagateTo(x, xx0, xrho);
+    if (!AdjustSector(track)) break;
+  
+    //Update track
+    Double_t chi2 = track->GetPredictedChi2(ptrTracklet);
+    if(chi2<1e+10) track->Update(ptrTracklet, chi2);
+
+    if(!up) continue;
+
+               //Reset material budget if 2 consecutive gold
+               if(iplane>0 && track->GetTracklet(iplane-1) && ptrTracklet->GetN() + track->GetTracklet(iplane-1)->GetN() > 20) track->SetBudget(2, 0.);
+       } // end planes loop
+
+  // extrapolation
+  while(ip < np){
+    if(((up?-1:1) * (points[ip].GetX() - track->GetX()) < 0) && !PropagateToX(*track, points[ip].GetX(), fgkMaxStep)) return -1.;
+    
+    Double_t xyz[3]; // should also get the covariance
+    track->GetXYZ(xyz); points[ip].SetXYZ(xyz[0], xyz[1], xyz[2]);
+    ip++;
+  }
+
+       return track->GetChi2();
+}
+
+//_________________________________________________________________________
+Float_t AliTRDtrackerV1::CalculateChi2Z(AliTRDseedV1 *tracklets, Double_t offset, Double_t slope, Double_t xref)
+{
+  //
+  // Calculates the chi2-value of the track in z-Direction including tilting pad correction.
+  // A linear dependence on the x-value serves as a model.
+  // The parameters are related to the tilted Riemann fit.
+  // Parameters: - Array of tracklets (AliTRDseedV1) related to the track candidate
+  //             - the offset for the reference x
+  //             - the slope
+  //             - the reference x position
+  // Output:     - The Chi2 value of the track in z-Direction
+  //
+  Float_t chi2Z = 0, nLayers = 0;
+  for (Int_t iLayer = 0; iLayer < AliTRDgeometry::kNlayer; iLayer++) {
+    if(!tracklets[iLayer].IsOK()) continue;
+    Double_t z = offset + slope * (tracklets[iLayer].GetX0() - xref);
+    chi2Z += TMath::Abs(tracklets[iLayer].GetMeanz() - z);
+    nLayers++;
+  }
+  chi2Z /= TMath::Max((nLayers - 3.0),1.0);
+  return chi2Z;
 }
 
 //_____________________________________________________________________________
@@ -844,7 +1487,7 @@ Int_t AliTRDtrackerV1::PropagateToX(AliTRDtrackV1 &t, Double_t xToGo, Double_t m
 
     // Calculate the mean material budget between start and
     // end point of this prolongation step
-    AliTracker::MeanMaterialBudget(xyz0,xyz1,param);
+    if(AliTracker::MeanMaterialBudget(xyz0, xyz1, param)<=0.) return 0;
 
     // Propagate the track to the X-position after the next step
     if (!t.PropagateTo(x,param[1],param[0]*param[4])) {
@@ -863,108 +1506,263 @@ Int_t AliTRDtrackerV1::PropagateToX(AliTRDtrackV1 &t, Double_t xToGo, Double_t m
 
 }
 
-//____________________________________________________________________
-void AliTRDtrackerV1::UnloadClusters() 
-{ 
+
+//_____________________________________________________________________________
+Int_t AliTRDtrackerV1::ReadClusters(TClonesArray* &array, TTree *clusterTree) const
+{
   //
-  // Clears the arrays of clusters and tracks. Resets sectors and timebins 
+  // Reads AliTRDclusters from the file. 
+  // The names of the cluster tree and branches 
+  // should match the ones used in AliTRDclusterizer::WriteClusters()
   //
 
-  Int_t i;
-  Int_t nentr;
+  Int_t nsize = Int_t(clusterTree->GetTotBytes() / (sizeof(AliTRDcluster))); 
+  TObjArray *clusterArray = new TObjArray(nsize+1000); 
+  
+  TBranch *branch = clusterTree->GetBranch("TRDcluster");
+  if (!branch) {
+    AliError("Can't get the branch !");
+    return 1;
+  }
+  branch->SetAddress(&clusterArray); 
+  
+  if(!fClusters){ 
+    Float_t nclusters =  fReconstructor->GetRecoParam()->GetNClusters();
+    if(fReconstructor->IsHLT()) nclusters /= AliTRDgeometry::kNsector;
+    array = new TClonesArray("AliTRDcluster", Int_t(nclusters));
+    array->SetOwner(kTRUE);
+  }
+  
+  // Loop through all entries in the tree
+  Int_t nEntries   = (Int_t) clusterTree->GetEntries();
+  Int_t nbytes     = 0;
+  Int_t ncl        = 0;
+  AliTRDcluster *c = 0x0;
+  for (Int_t iEntry = 0; iEntry < nEntries; iEntry++) {
+    // Import the tree
+    nbytes += clusterTree->GetEvent(iEntry);  
+    
+    // Get the number of points in the detector
+    Int_t nCluster = clusterArray->GetEntriesFast();  
+    for (Int_t iCluster = 0; iCluster < nCluster; iCluster++) { 
+      if(!(c = (AliTRDcluster *) clusterArray->UncheckedAt(iCluster))) continue;
+      c->SetInChamber();
+      new((*fClusters)[ncl++]) AliTRDcluster(*c);
+      delete (clusterArray->RemoveAt(iCluster)); 
+    }
+
+  }
+  delete clusterArray;
+
+  return 0;
+}
+
+//_____________________________________________________________________________
+Int_t AliTRDtrackerV1::LoadClusters(TTree *cTree)
+{
+  //
+  // Fills clusters into TRD tracking sectors
+  //
+  
+  if(!fReconstructor->IsWritingClusters()){ 
+    fClusters = AliTRDReconstructor::GetClusters();
+  } else {
+    if (ReadClusters(fClusters, cTree)) {
+      AliError("Problem with reading the clusters !");
+      return 1;
+    }
+  }
+  SetClustersOwner();
 
-  nentr = fClusters->GetEntriesFast();
-  for (i = 0; i < nentr; i++) {
-    delete fClusters->RemoveAt(i);
+  if(!fClusters || !fClusters->GetEntriesFast()){ 
+    AliInfo("No TRD clusters");
+    return 1;
   }
-  fNclusters = 0;
+
+  //Int_t nin = 
+  BuildTrackingContainers();  
+
+  //Int_t ncl  = fClusters->GetEntriesFast();
+  //AliInfo(Form("Clusters %d [%6.2f %% in the active volume]", ncl, 100.*float(nin)/ncl));
+
+  return 0;
+}
+
+//_____________________________________________________________________________
+Int_t AliTRDtrackerV1::LoadClusters(TClonesArray *clusters)
+{
+  //
+  // Fills clusters into TRD tracking sectors
+  // Function for use in the HLT
   
-       if(fTracklets){
-       for (i = 0; i < fTracklets->GetEntriesFast(); i++) delete fTracklets->RemoveAt(i);
-       }
+  if(!clusters || !clusters->GetEntriesFast()){ 
+    AliInfo("No TRD clusters");
+    return 1;
+  }
+
+  fClusters = clusters;
+  SetClustersOwner();
+
+  //Int_t nin = 
+  BuildTrackingContainers();  
+
+  //Int_t ncl  = fClusters->GetEntriesFast();
+  //AliInfo(Form("Clusters %d [%6.2f %% in the active volume]", ncl, 100.*float(nin)/ncl));
 
-  nentr = fSeeds->GetEntriesFast();
-  for (i = 0; i < nentr; i++) {
-    delete fSeeds->RemoveAt(i);
+  return 0;
+}
+
+
+//____________________________________________________________________
+Int_t AliTRDtrackerV1::BuildTrackingContainers()
+{
+// Building tracking containers for clusters
+
+  Int_t nin =0, icl = fClusters->GetEntriesFast();
+  while (icl--) {
+    AliTRDcluster *c = (AliTRDcluster *) fClusters->UncheckedAt(icl);
+    if(c->IsInChamber()) nin++;
+    Int_t detector       = c->GetDetector();
+    Int_t sector         = fGeom->GetSector(detector);
+    Int_t stack          = fGeom->GetStack(detector);
+    Int_t layer          = fGeom->GetLayer(detector);
+    
+    fTrSec[sector].GetChamber(stack, layer, kTRUE)->InsertCluster(c, icl);
   }
 
-  nentr = fTracks->GetEntriesFast();
-       for (i = 0; i < nentr; i++) {
-    delete fTracks->RemoveAt(i);
+  const AliTRDCalDet *cal = AliTRDcalibDB::Instance()->GetT0Det();
+  for(int isector =0; isector<AliTRDgeometry::kNsector; isector++){ 
+    if(!fTrSec[isector].GetNChambers()) continue;
+    fTrSec[isector].Init(fReconstructor, cal);
   }
 
-  Int_t nsec = AliTRDgeometry::kNsect;
-  for (i = 0; i < nsec; i++) {    
-    for(Int_t pl = 0; pl < fTrSec[i]->GetNumberOfLayers(); pl++) {
-      fTrSec[i]->GetLayer(pl)->Clear();
-    }
+  return nin;
+}
+
+
+
+//____________________________________________________________________
+void AliTRDtrackerV1::UnloadClusters() 
+{ 
+  //
+  // Clears the arrays of clusters and tracks. Resets sectors and timebins 
+  //
+
+  if(fTracks) fTracks->Delete(); 
+  if(fTracklets) fTracklets->Delete();
+  if(fClusters){ 
+    if(IsClustersOwner()) fClusters->Delete();
+    
+    // save clusters array in the reconstructor for further use.
+    if(!fReconstructor->IsWritingClusters()){
+      AliTRDReconstructor::SetClusters(fClusters);
+      SetClustersOwner(kFALSE);
+    } else AliTRDReconstructor::SetClusters(0x0);
   }
 
+  for (int i = 0; i < AliTRDgeometry::kNsector; i++) fTrSec[i].Clear();
+
+  // Increment the Event Number
+  AliTRDtrackerDebug::SetEventNumber(AliTRDtrackerDebug::GetEventNumber()  + 1);
+}
+
+//_____________________________________________________________________________
+Bool_t AliTRDtrackerV1::AdjustSector(AliTRDtrackV1 *track) 
+{
+  //
+  // Rotates the track when necessary
+  //
+
+  Double_t alpha = AliTRDgeometry::GetAlpha(); 
+  Double_t y     = track->GetY();
+  Double_t ymax  = track->GetX()*TMath::Tan(0.5*alpha);
+
+  if      (y >  ymax) {
+    if (!track->Rotate( alpha)) {
+      return kFALSE;
+    }
+  } 
+  else if (y < -ymax) {
+    if (!track->Rotate(-alpha)) {
+      return kFALSE;   
+    }
+  } 
+
+  return kTRUE;
+
 }
 
+
 //____________________________________________________________________
 AliTRDseedV1* AliTRDtrackerV1::GetTracklet(AliTRDtrackV1 *track, Int_t p, Int_t &idx)
 {
-// Find tracklet for TRD track <track>
-// Parameters
-// - track
-// - sector
-// - plane
-// - index
-// Output
-// tracklet
-// index
-// Detailed description
-//
-       idx = track->GetTrackletIndex(p);
-       //AliInfo(Form("looking for tracklet in plane %d idx %d [%d]", p, idx, track->GetTrackletIndex(p)));
-       AliTRDseedV1 *tracklet = idx<0 ? 0x0 : (AliTRDseedV1*)fTracklets->UncheckedAt(idx);
-       //AliInfo(Form("found 0x%x @ %d", tracklet, idx));
-
-//   Int_t *index = track->GetTrackletIndexes();
-//   for (UInt_t i = 0; i < 6; i++) AliInfo(Form("index[%d] = %d", i, index[i]));
-// 
-//     for (UInt_t i = 0; i < 6/*kMaxTimeBinIndex*/; i++) {
-//     if (index[i] < 0) continue;
-// 
-//             tracklet = (AliTRDseedV1*)fTracklets->UncheckedAt(index[i]);
-//             if(!tracklet) break;
-// 
-//             if(tracklet->GetPlane() != p) continue;
-// 
-//             idx = index[i];
-//     }
+  // Find tracklet for TRD track <track>
+  // Parameters
+  // - track
+  // - sector
+  // - plane
+  // - index
+  // Output
+  // tracklet
+  // index
+  // Detailed description
+  //
+  idx = track->GetTrackletIndex(p);
+  AliTRDseedV1 *tracklet = (idx==0xffff) ? 0x0 : (AliTRDseedV1*)fTracklets->UncheckedAt(idx);
 
-       return tracklet;
+  return tracklet;
 }
 
 //____________________________________________________________________
-Int_t AliTRDtrackerV1::SetTracklet(AliTRDseedV1 *tracklet)
+AliTRDseedV1* AliTRDtrackerV1::SetTracklet(AliTRDseedV1 *tracklet)
 {
-// Add this tracklet to the list of tracklets stored in the tracker
-//
-// Parameters
-//   - tracklet : pointer to the tracklet to be added to the list
-//
-// Output
-//   - the index of the new tracklet in the tracker tracklets list
-//
-// Detailed description
-// Build the tracklets list if it is not yet created (late initialization)
-// and adds the new tracklet to the list.
-//
-       if(!fTracklets){
-               fTracklets = new TClonesArray("AliTRDseedV1", AliTRDgeometry::Nsect()*kMaxTracksStack);
-               fTracklets->SetOwner(kTRUE);
-       }
-       Int_t nentries = fTracklets->GetEntriesFast();
-       new ((*fTracklets)[nentries]) AliTRDseedV1(*tracklet);
-       return nentries;
+  // Add this tracklet to the list of tracklets stored in the tracker
+  //
+  // Parameters
+  //   - tracklet : pointer to the tracklet to be added to the list
+  //
+  // Output
+  //   - the index of the new tracklet in the tracker tracklets list
+  //
+  // Detailed description
+  // Build the tracklets list if it is not yet created (late initialization)
+  // and adds the new tracklet to the list.
+  //
+  if(!fTracklets){
+    fTracklets = new TClonesArray("AliTRDseedV1", AliTRDgeometry::Nsector()*kMaxTracksStack);
+    fTracklets->SetOwner(kTRUE);
+  }
+  Int_t nentries = fTracklets->GetEntriesFast();
+  return new ((*fTracklets)[nentries]) AliTRDseedV1(*tracklet);
 }
 
 //____________________________________________________________________
-Int_t AliTRDtrackerV1::Clusters2TracksSM(AliTRDtracker::AliTRDtrackingSector *sector
-                                       , AliESDEvent *esd)
+AliTRDtrackV1* AliTRDtrackerV1::SetTrack(AliTRDtrackV1 *track)
+{
+  // Add this track to the list of tracks stored in the tracker
+  //
+  // Parameters
+  //   - track : pointer to the track to be added to the list
+  //
+  // Output
+  //   - the pointer added
+  //
+  // Detailed description
+  // Build the tracks list if it is not yet created (late initialization)
+  // and adds the new track to the list.
+  //
+  if(!fTracks){
+    fTracks = new TClonesArray("AliTRDtrackV1", AliTRDgeometry::Nsector()*kMaxTracksStack);
+    fTracks->SetOwner(kTRUE);
+  }
+  Int_t nentries = fTracks->GetEntriesFast();
+  return new ((*fTracks)[nentries]) AliTRDtrackV1(*track);
+}
+
+
+
+//____________________________________________________________________
+Int_t AliTRDtrackerV1::Clusters2TracksSM(Int_t sector, AliESDEvent *esd)
 {
   //
   // Steer tracking for one SM.
@@ -982,60 +1780,42 @@ Int_t AliTRDtrackerV1::Clusters2TracksSM(AliTRDtracker::AliTRDtrackingSector *se
   // 1. Unpack AliTRDpropagationLayers objects for each stack.
   // 2. Launch stack tracking. 
   //    See AliTRDtrackerV1::Clusters2TracksStack() for details.
-  // 3. Pack results in the ESD event.
-  //
-       
-       AliTRDpadPlane *pp = 0x0;
-       
-       // allocate space for esd tracks in this SM
-       TClonesArray esdTrackList("AliESDtrack", 2*kMaxTracksStack);
-       esdTrackList.SetOwner();
-       AliTRDcalibDB *cal = AliTRDcalibDB::Instance();
-       Int_t nTimeBins = cal->GetNumberOfTimeBins();
-       const Int_t kFindable = Int_t(fRecoParam->GetFindableClusters()*6.*nTimeBins);
-       
-       Int_t ntracks = 0;
-       Int_t nClStack = 0;
-       for(int istack = 0; istack<AliTRDpropagationLayer::kZones; istack++){
-               AliTRDstackLayer stackLayer[kNPlanes*kNTimeBins];
-               
-               nClStack = 0;
-               //AliInfo(Form("Processing stack %i ...",istack));
-               //AliInfo("Building stack propagation layers ...");
-               for(int ilayer=0; ilayer<kNPlanes*nTimeBins; ilayer++){
-                       pp = fGeom->GetPadPlane((Int_t)(ilayer/nTimeBins), istack);
-                       Double_t stacklength = (pp->GetNrows() - 2) * pp->GetLengthIPad() 
-                                             + 2 * pp->GetLengthOPad() + 2 * pp->GetLengthRim();
-                       //Debug
-                       Double_t z0  = fGeom->GetRow0((Int_t)(ilayer/nTimeBins),istack,0);
-                       const AliTRDpropagationLayer ksmLayer(*(sector->GetLayer(ilayer)));
-                       stackLayer[ilayer] = ksmLayer;
-#ifdef DEBUG
-                       stackLayer[ilayer].SetDebugStream(fDebugStreamer);
-#endif                 
-                       stackLayer[ilayer].SetRange(z0 - stacklength, stacklength);
-                       stackLayer[ilayer].SetSector(sector->GetSector());
-                       stackLayer[ilayer].SetStackNr(istack);
-                       stackLayer[ilayer].SetNRows(pp->GetNrows());
-                       stackLayer[ilayer].SetRecoParam(fRecoParam);
-                       stackLayer[ilayer].BuildIndices();
-                       nClStack += stackLayer[ilayer].GetNClusters();
-               }
-               //AliInfo(Form("Finish building stack propagation layers. nClusters %d.", nClStack));
-               if(nClStack < kFindable) continue;
-               ntracks += Clusters2TracksStack(&stackLayer[0], &esdTrackList);
-       }
-       //AliInfo(Form("Found %d tracks in SM", ntracks));
-       
-       for(int itrack=0; itrack<ntracks; itrack++) 
-          esd->AddTrack((AliESDtrack*)esdTrackList[itrack]);
+  // 3. Pack results in the ESD event.
+  //
+  
+  // allocate space for esd tracks in this SM
+  TClonesArray esdTrackList("AliESDtrack", 2*kMaxTracksStack);
+  esdTrackList.SetOwner();
+  
+  Int_t nTracks   = 0;
+  Int_t nChambers = 0;
+  AliTRDtrackingChamber **stack = 0x0, *chamber = 0x0;
+  for(int istack = 0; istack<AliTRDgeometry::kNstack; istack++){
+    if(!(stack = fTrSec[sector].GetStack(istack))) continue;
+    nChambers = 0;
+    for(int ilayer=0; ilayer<AliTRDgeometry::kNlayer; ilayer++){
+      if(!(chamber = stack[ilayer])) continue;
+      if(chamber->GetNClusters() < fgNTimeBins * fReconstructor->GetRecoParam() ->GetFindableClusters()) continue;
+      nChambers++;
+      //AliInfo(Form("sector %d stack %d layer %d clusters %d", sector, istack, ilayer, chamber->GetNClusters()));
+    }
+    if(nChambers < 4) continue;
+    //AliInfo(Form("Doing stack %d", istack));
+    nTracks += Clusters2TracksStack(stack, &esdTrackList);
+  }
+  //AliInfo(Form("Found %d tracks in SM %d [%d]\n", nTracks, sector, esd->GetNumberOfTracks()));
+  
+  for(int itrack=0; itrack<nTracks; itrack++)
+    esd->AddTrack((AliESDtrack*)esdTrackList[itrack]);
 
-       return ntracks;
+  // Reset Track and Candidate Number
+  AliTRDtrackerDebug::SetCandidateNumber(0);
+  AliTRDtrackerDebug::SetTrackNumber(0);
+  return nTracks;
 }
 
 //____________________________________________________________________
-Int_t AliTRDtrackerV1::Clusters2TracksStack(AliTRDstackLayer *layer
-                                          , TClonesArray *esdTrackList)
+Int_t AliTRDtrackerV1::Clusters2TracksStack(AliTRDtrackingChamber **stack, TClonesArray *esdTrackList)
 {
   //
   // Make tracks in one TRD stack.
@@ -1063,290 +1843,310 @@ Int_t AliTRDtrackerV1::Clusters2TracksStack(AliTRDstackLayer *layer
   // 8. Build ESD track and register it to the output list
   //
 
-       AliTRDseedV1 sseed[kMaxTracksStack*6]; // to be initialized
-       Int_t pars[4]; // MakeSeeds parameters
+  const AliTRDCalDet *cal = AliTRDcalibDB::Instance()->GetT0Det();
+  AliTRDtrackingChamber *chamber = 0x0;
+  AliTRDseedV1 sseed[kMaxTracksStack*6]; // to be initialized
+  Int_t pars[4]; // MakeSeeds parameters
 
-       //Double_t alpha = AliTRDgeometry::GetAlpha();
-       //Double_t shift = .5 * alpha;
-       Int_t configs[kNConfigs];
-       
-       // Build initial seeding configurations
-       Double_t quality = BuildSeedingConfigs(layer, configs);
-#ifdef DEBUG
-               if(AliTRDReconstructor::StreamLevel() > 1) 
-                  AliInfo(Form("Plane config %d %d %d Quality %f"
-                              , configs[0], configs[1], configs[2], quality));
-#endif
-
-       // Initialize contors
-       Int_t ntracks,      // number of TRD track candidates
-             ntracks1,     // number of registered TRD tracks/iter
-             ntracks2 = 0; // number of all registered TRD tracks in stack
-       fSieveSeeding = 0;
-       do{
-               // Loop over seeding configurations
-               ntracks = 0; ntracks1 = 0;
-               for (Int_t iconf = 0; iconf<3; iconf++) {
-                       pars[0] = configs[iconf];
-                       pars[1] = layer->GetStackNr();
-                       pars[2] = ntracks;
-                       ntracks = MakeSeeds(layer, &sseed[6*ntracks], pars);
-                       if(ntracks == kMaxTracksStack) break;
-               }
-#ifdef DEBUG
-               if(AliTRDReconstructor::StreamLevel() > 1) AliInfo(Form("Candidate TRD tracks %d in stack %d iteration %d.", ntracks, pars[1], fSieveSeeding));
-#endif         
-               if(!ntracks) break;
-               
-               // Sort the seeds according to their quality
-               Int_t sort[kMaxTracksStack];
-               TMath::Sort(ntracks, fTrackQuality, sort, kTRUE);
-       
-               // Initialize number of tracks so far and logic switches
-               Int_t ntracks0 = esdTrackList->GetEntriesFast();
-               Bool_t signedTrack[kMaxTracksStack];
-               Bool_t fakeTrack[kMaxTracksStack];
-               for (Int_t i=0; i<ntracks; i++){
-                       signedTrack[i] = kFALSE;
-                       fakeTrack[i] = kFALSE;
-               }
-               //AliInfo("Selecting track candidates ...");
-               
-               // Sieve clusters in decreasing order of track quality
-               Double_t trackParams[7];
-//             AliTRDseedV1 *lseed = 0x0;
-               Int_t jSieve = 0, candidates;
-               do{
-                       //AliInfo(Form("\t\tITER = %i ", jSieve));
-
-                       // Check track candidates
-                       candidates = 0;
-                       for (Int_t itrack = 0; itrack < ntracks; itrack++) {
-                               Int_t trackIndex = sort[itrack];
-                               if (signedTrack[trackIndex] || fakeTrack[trackIndex]) continue;
-       
-                               
-                               // Calculate track parameters from tracklets seeds
-                               Int_t labelsall[1000];
-                               Int_t nlabelsall = 0;
-                               Int_t naccepted  = 0;
-                               Int_t ncl        = 0;
-                               Int_t nused      = 0;
-                               Int_t nlayers    = 0;
-                               Int_t findable   = 0;
-                               for (Int_t jLayer = 0; jLayer < kNPlanes; jLayer++) {
-                                       Int_t jseed = kNPlanes*trackIndex+jLayer;
-                                       if (TMath::Abs(sseed[jseed].GetYref(0) / sseed[jseed].GetX0()) < 0.15) 
-                                          findable++;
-       
-                                       if(!sseed[jseed].IsOK()) continue;
-                                       sseed[jseed].UpdateUsed();
-                                       ncl   += sseed[jseed].GetN2();
-                                       nused += sseed[jseed].GetNUsed();
-                                       nlayers++;
-       
-                                       // Cooking label
-                                       for (Int_t itime = 0; itime < fTimeBinsPerPlane; itime++) {
-                                               if(!sseed[jseed].IsUsable(itime)) continue;
-                                               naccepted++;
-                                               Int_t tindex = 0, ilab = 0;
-                                               while(ilab<3 && (tindex = sseed[jseed].GetClusters(itime)->GetLabel(ilab)) >= 0){
-                                                       labelsall[nlabelsall++] = tindex;
-                                                       ilab++;
-                                               }
-                                       }
-                               }
-                               // Filter duplicated tracks
-                               if (nused > 30){
-                                       printf("Skip %d nused %d\n", trackIndex, nused);
-                                       fakeTrack[trackIndex] = kTRUE;
-                                       continue;
-                               }
-                               if (Float_t(nused)/ncl >= .25){
-                                       printf("Skip %d nused/ncl >= .25\n", trackIndex);
-                                       fakeTrack[trackIndex] = kTRUE;
-                                       continue;
-                               }
-                               
-                               // Classify tracks
-                               Bool_t skip = kFALSE;
-                               switch(jSieve){
-                               case 0:
-                                       if(nlayers < 6) {skip = kTRUE; break;}
-                                       if(TMath::Log(1.E-9+fTrackQuality[trackIndex]) < -5.){skip = kTRUE; break;}
-                                       break;
-       
-                               case 1:
-                                       if(nlayers < findable){skip = kTRUE; break;}
-                                       if(TMath::Log(1.E-9+fTrackQuality[trackIndex]) < -4.){skip = kTRUE; break;}
-                                       break;
-       
-                               case 2:
-                                       if ((nlayers == findable) || (nlayers == 6)) { skip = kTRUE; break;}
-                                       if (TMath::Log(1.E-9+fTrackQuality[trackIndex]) < -6.0){skip = kTRUE; break;}
-                                       break;
-       
-                               case 3:
-                                       if (TMath::Log(1.E-9+fTrackQuality[trackIndex]) < -5.){skip = kTRUE; break;}
-                                       break;
-       
-                               case 4:
-                                       if (nlayers == 3){skip = kTRUE; break;}
-                                       //if (TMath::Log(1.E-9+fTrackQuality[trackIndex]) - nused/(nlayers-3.0) < -15.0){skip = kTRUE; break;}
-                                       break;
-                               }
-                               if(skip){
-                                       candidates++;
-                                       printf("REJECTED : %d [%d] nlayers %d trackQuality = %e nused %d\n", itrack, trackIndex, nlayers, fTrackQuality[trackIndex], nused);
-                                       continue;
-                               }
-                               signedTrack[trackIndex] = kTRUE;
-                                               
-
-                               // Build track label - what happens if measured data ???
-                               Int_t labels[1000];
-                               Int_t outlab[1000];
-                               Int_t nlab = 0;
-                               for (Int_t iLayer = 0; iLayer < 6; iLayer++) {
-                                       Int_t jseed = kNPlanes*trackIndex+iLayer;
-                                       if(!sseed[jseed].IsOK()) continue;
-                                       for(int ilab=0; ilab<2; ilab++){
-                                               if(sseed[jseed].GetLabels(ilab) < 0) continue;
-                                               labels[nlab] = sseed[jseed].GetLabels(ilab);
-                                               nlab++;
-                                       }
-                               }
-                               Freq(nlab,labels,outlab,kFALSE);
-                               Int_t   label     = outlab[0];
-                               Int_t   frequency = outlab[1];
-                               Freq(nlabelsall,labelsall,outlab,kFALSE);
-                               Int_t   label1    = outlab[0];
-                               Int_t   label2    = outlab[2];
-                               Float_t fakeratio = (naccepted - outlab[1]) / Float_t(naccepted);
-       
-                               
-                               // Sign clusters
-                               AliTRDcluster *cl = 0x0; Int_t clusterIndex = -1;
-                               for (Int_t jLayer = 0; jLayer < 6; jLayer++) {
-                                       Int_t jseed = kNPlanes*trackIndex+jLayer;
-                                       if(!sseed[jseed].IsOK()) continue;
-                                       if(TMath::Abs(sseed[jseed].GetYfit(1) - sseed[jseed].GetYfit(1)) >= .2) continue; // check this condition with Marian
-                                       sseed[jseed].UseClusters();
-                                       if(!cl){
-                                               Int_t ic = 0;
-                                               while(!(cl = sseed[jseed].GetClusters(ic))) ic++;
-                                               clusterIndex =  sseed[jseed].GetIndexes(ic);
-                                       }
-                               }
-                               if(!cl) continue;
-
-                               
-                               // Build track parameters
-                               AliTRDseedV1 *lseed =&sseed[trackIndex*6];
-                               Int_t idx = 0;
-                               while(idx<3 && !lseed->IsOK()) {
-                                       idx++;
-                                       lseed++;
-                               }
-                               Double_t cR = lseed->GetC();
-                               trackParams[1] = lseed->GetYref(0);
-                               trackParams[2] = lseed->GetZref(0);
-                               trackParams[3] = lseed->GetX0() * cR - TMath::Sin(TMath::ATan(lseed->GetYref(1)));
-                               trackParams[4] = lseed->GetZref(1) / TMath::Sqrt(1. + lseed->GetYref(1) * lseed->GetYref(1));
-                               trackParams[5] = cR;
-                               trackParams[0] = lseed->GetX0();
-                               trackParams[6] = layer[0].GetSector();/* *alpha+shift;  // Supermodule*/
-
-#ifdef DEBUG
-                               if(AliTRDReconstructor::StreamLevel() > 1) printf("Track %d [%d] nlayers %d trackQuality = %e nused %d, yref = %3.3f\n", itrack, trackIndex, nlayers, fTrackQuality[trackIndex], nused, trackParams[1]);
-                               
-                               if(AliTRDReconstructor::StreamLevel() >= 1){
-                                       Int_t sector = layer[0].GetSector();
-                                       Int_t nclusters = 0;
-                                       AliTRDseedV1 *dseed[6];
-                                       for(int is=0; is<6; is++){
-                                               dseed[is] = new AliTRDseedV1(sseed[trackIndex*6+is]);
-                                               dseed[is]->SetOwner();
-                                               nclusters += sseed[is].GetN2();
-                                               //for(int ic=0; ic<30; ic++) if(sseed[trackIndex*6+is].GetClusters(ic)) printf("l[%d] tb[%d] cptr[%p]\n", is, ic, sseed[trackIndex*6+is].GetClusters(ic));
-                                       }
-                                       //Int_t eventNrInFile = esd->GetEventNumberInFile();
-                                       //AliInfo(Form("Number of clusters %d.", nclusters));
-                                       TTreeSRedirector &cstreamer = *fDebugStreamer;
-                                       cstreamer << "Clusters2TracksStack"
-                                               << "Iter="      << fSieveSeeding
-                                               << "Like="      << fTrackQuality[trackIndex]
-                                               << "S0.="       << dseed[0]
-                                               << "S1.="       << dseed[1]
-                                               << "S2.="       << dseed[2]
-                                               << "S3.="       << dseed[3]
-                                               << "S4.="       << dseed[4]
-                                               << "S5.="       << dseed[5]
-                                               << "p0=" << trackParams[0]
-                                               << "p1=" << trackParams[1]
-                                               << "p2=" << trackParams[2]
-                                               << "p3=" << trackParams[3]
-                                               << "p4=" << trackParams[4]
-                                               << "p5=" << trackParams[5]
-                                               << "p6=" << trackParams[6]
-                                               << "Sector="    << sector
-                                               << "Stack="     << pars[1]
-                                               << "Label="     << label
-                                               << "Label1="    << label1
-                                               << "Label2="    << label2
-                                               << "FakeRatio=" << fakeratio
-                                               << "Freq="      << frequency
-                                               << "Ncl="       << ncl
-                                               << "NLayers="   << nlayers
-                                               << "Findable="  << findable
-                                               << "NUsed="     << nused
-                                               << "\n";
-                                       //???for(int is=0; is<6; is++) delete dseed[is];
-                               }
-#endif
-                       
-                               AliTRDtrackV1 *track = AliTRDtrackerV1::MakeTrack(&sseed[trackIndex*kNPlanes], trackParams);
-                               if(!track){
-                                       AliWarning("Fail to build a TRD Track.");
-                                       continue;
-                               }
-                               AliInfo("End of MakeTrack()");
-                               AliESDtrack esdTrack;
-                               esdTrack.UpdateTrackParams(track, AliESDtrack::kTRDout);
-                               esdTrack.SetLabel(track->GetLabel());
-                               new ((*esdTrackList)[ntracks0++]) AliESDtrack(esdTrack);
-                               ntracks1++;
-                       }
-
-                       jSieve++;
-               } while(jSieve<5 && candidates); // end track candidates sieve
-               if(!ntracks1) break;
-
-               // increment counters
-               ntracks2 += ntracks1;
-               fSieveSeeding++;
-
-               // Rebuild plane configurations and indices taking only unused clusters into account
-               quality = BuildSeedingConfigs(layer, configs);
-               //if(quality < fRecoParam->GetPlaneQualityThreshold()) break;
-               
-               for(Int_t il = 0; il < kNPlanes * fTimeBinsPerPlane; il++) layer[il].BuildIndices(fSieveSeeding);
-
-#ifdef DEBUG
-                               if(AliTRDReconstructor::StreamLevel() > 1) AliInfo(Form("Sieve level %d Plane config %d %d %d Quality %f", fSieveSeeding, configs[0], configs[1], configs[2], quality));
-#endif
-       } while(fSieveSeeding<10); // end stack clusters sieve
-       
+  //Double_t alpha = AliTRDgeometry::GetAlpha();
+  //Double_t shift = .5 * alpha;
+  Int_t configs[kNConfigs];
+  
+  // Build initial seeding configurations
+  Double_t quality = BuildSeedingConfigs(stack, configs);
+  if(fReconstructor->GetStreamLevel(AliTRDReconstructor::kTracker) > 1){
+    AliInfo(Form("Plane config %d %d %d Quality %f"
+    , configs[0], configs[1], configs[2], quality));
+  }
+
+  
+  // Initialize contors
+  Int_t ntracks,      // number of TRD track candidates
+    ntracks1,     // number of registered TRD tracks/iter
+    ntracks2 = 0; // number of all registered TRD tracks in stack
+  fSieveSeeding = 0;
+
+  // Get stack index
+  Int_t ic = 0; AliTRDtrackingChamber **cIter = &stack[0];
+  while(ic<kNPlanes && !(*cIter)){ic++; cIter++;}
+  if(!(*cIter)) return ntracks2;
+  Int_t istack = fGeom->GetStack((*cIter)->GetDetector());
+
+  do{
+    // Loop over seeding configurations
+    ntracks = 0; ntracks1 = 0;
+    for (Int_t iconf = 0; iconf<3; iconf++) {
+      pars[0] = configs[iconf];
+      pars[1] = ntracks;
+      pars[2] = istack;
+      ntracks = MakeSeeds(stack, &sseed[6*ntracks], pars);
+      if(ntracks == kMaxTracksStack) break;
+    }
+    if(fReconstructor->GetStreamLevel(AliTRDReconstructor::kTracker) > 1) AliInfo(Form("Candidate TRD tracks %d in iteration %d.", ntracks, fSieveSeeding));
+    
+    if(!ntracks) break;
+    
+    // Sort the seeds according to their quality
+    Int_t sort[kMaxTracksStack];
+    TMath::Sort(ntracks, fTrackQuality, sort, kTRUE);
+  
+    // Initialize number of tracks so far and logic switches
+    Int_t ntracks0 = esdTrackList->GetEntriesFast();
+    Bool_t signedTrack[kMaxTracksStack];
+    Bool_t fakeTrack[kMaxTracksStack];
+    for (Int_t i=0; i<ntracks; i++){
+      signedTrack[i] = kFALSE;
+      fakeTrack[i] = kFALSE;
+    }
+    //AliInfo("Selecting track candidates ...");
+    
+    // Sieve clusters in decreasing order of track quality
+    Double_t trackParams[7];
+    //                 AliTRDseedV1 *lseed = 0x0;
+    Int_t jSieve = 0, candidates;
+    do{
+      //AliInfo(Form("\t\tITER = %i ", jSieve));
+
+      // Check track candidates
+      candidates = 0;
+      for (Int_t itrack = 0; itrack < ntracks; itrack++) {
+        Int_t trackIndex = sort[itrack];
+        if (signedTrack[trackIndex] || fakeTrack[trackIndex]) continue;
+  
+        
+        // Calculate track parameters from tracklets seeds
+        Int_t ncl        = 0;
+        Int_t nused      = 0;
+        Int_t nlayers    = 0;
+        Int_t findable   = 0;
+        for (Int_t jLayer = 0; jLayer < kNPlanes; jLayer++) {
+          Int_t jseed = kNPlanes*trackIndex+jLayer;
+          if(!sseed[jseed].IsOK()) continue;
+          if (TMath::Abs(sseed[jseed].GetYref(0) / sseed[jseed].GetX0()) < 0.15) findable++;
+        
+          sseed[jseed].UpdateUsed();
+          ncl   += sseed[jseed].GetN2();
+          nused += sseed[jseed].GetNUsed();
+          nlayers++;
+        }
+
+  // Filter duplicated tracks
+  if (nused > 30){
+    //printf("Skip %d nused %d\n", trackIndex, nused);
+    fakeTrack[trackIndex] = kTRUE;
+    continue;
+  }
+  if (Float_t(nused)/ncl >= .25){
+    //printf("Skip %d nused/ncl >= .25\n", trackIndex);
+    fakeTrack[trackIndex] = kTRUE;
+    continue;
+  }
+        
+  // Classify tracks
+  Bool_t skip = kFALSE;
+  switch(jSieve){
+  case 0:
+    if(nlayers < 6) {skip = kTRUE; break;}
+    if(TMath::Log(1.E-9+fTrackQuality[trackIndex]) < -5.){skip = kTRUE; break;}
+    break;
+  
+  case 1:
+    if(nlayers < findable){skip = kTRUE; break;}
+    if(TMath::Log(1.E-9+fTrackQuality[trackIndex]) < -4.){skip = kTRUE; break;}
+    break;
+  
+  case 2:
+    if ((nlayers == findable) || (nlayers == 6)) { skip = kTRUE; break;}
+    if (TMath::Log(1.E-9+fTrackQuality[trackIndex]) < -6.0){skip = kTRUE; break;}
+    break;
+  
+  case 3:
+    if (TMath::Log(1.E-9+fTrackQuality[trackIndex]) < -5.){skip = kTRUE; break;}
+    break;
+  
+  case 4:
+    if (nlayers == 3){skip = kTRUE; break;}
+    //if (TMath::Log(1.E-9+fTrackQuality[trackIndex]) - nused/(nlayers-3.0) < -15.0){skip = kTRUE; break;}
+    break;
+  }
+  if(skip){
+    candidates++;
+    //printf("REJECTED : %d [%d] nlayers %d trackQuality = %e nused %d\n", itrack, trackIndex, nlayers, fTrackQuality[trackIndex], nused);
+    continue;
+  }
+  signedTrack[trackIndex] = kTRUE;
+            
+        
+  // Sign clusters
+  AliTRDcluster *cl = 0x0; Int_t clusterIndex = -1;
+  for (Int_t jLayer = 0; jLayer < kNPlanes; jLayer++) {
+    Int_t jseed = kNPlanes*trackIndex+jLayer;
+    if(!sseed[jseed].IsOK()) continue;
+    if(TMath::Abs(sseed[jseed].GetYfit(1) - sseed[jseed].GetYfit(1)) >= .2) continue; // check this condition with Marian
+    sseed[jseed].UseClusters();
+    if(!cl){
+      ic = 0;
+      while(!(cl = sseed[jseed].GetClusters(ic))) ic++;
+      clusterIndex =  sseed[jseed].GetIndexes(ic);
+    }
+  }
+  if(!cl) continue;
+
+        
+  // Build track parameters
+  AliTRDseedV1 *lseed =&sseed[trackIndex*6];
+/*  Int_t idx = 0;
+  while(idx<3 && !lseed->IsOK()) {
+    idx++;
+    lseed++;
+  }*/
+  Double_t x = lseed->GetX0();// - 3.5;
+  trackParams[0] = x; //NEW AB
+  trackParams[1] = lseed->GetYref(0); // lseed->GetYat(x);  
+  trackParams[2] = lseed->GetZref(0); // lseed->GetZat(x); 
+  trackParams[3] = TMath::Sin(TMath::ATan(lseed->GetYref(1)));
+  trackParams[4] = lseed->GetZref(1) / TMath::Sqrt(1. + lseed->GetYref(1) * lseed->GetYref(1));
+  trackParams[5] = lseed->GetC();
+  Int_t ich = 0; while(!(chamber = stack[ich])) ich++;
+  trackParams[6] = fGeom->GetSector(chamber->GetDetector());/* *alpha+shift;   // Supermodule*/
+
+  if(fReconstructor->GetStreamLevel(AliTRDReconstructor::kTracker) > 1){
+    AliInfo(Form("Track %d [%d] nlayers %d trackQuality = %e nused %d, yref = %3.3f", itrack, trackIndex, nlayers, fTrackQuality[trackIndex], nused, trackParams[1]));
+          
+    Int_t nclusters = 0;
+    AliTRDseedV1 *dseed[6];
+
+    // Build track label - what happens if measured data ???
+    Int_t labels[1000];
+    Int_t outlab[1000];
+    Int_t nlab = 0;
+
+    Int_t labelsall[1000];
+    Int_t nlabelsall = 0;
+    Int_t naccepted  = 0;
+
+    for (Int_t iLayer = 0; iLayer < kNPlanes; iLayer++) {
+      Int_t jseed = kNPlanes*trackIndex+iLayer;
+      dseed[iLayer] = new AliTRDseedV1(sseed[jseed]);
+      dseed[iLayer]->SetOwner();
+      nclusters += sseed[jseed].GetN2();
+      if(!sseed[jseed].IsOK()) continue;
+      for(int ilab=0; ilab<2; ilab++){
+        if(sseed[jseed].GetLabels(ilab) < 0) continue;
+        labels[nlab] = sseed[jseed].GetLabels(ilab);
+        nlab++;
+      }
+
+      // Cooking label
+      for (Int_t itime = 0; itime < fgNTimeBins; itime++) {
+        if(!sseed[jseed].IsUsable(itime)) continue;
+        naccepted++;
+        Int_t tindex = 0, ilab = 0;
+        while(ilab<3 && (tindex = sseed[jseed].GetClusters(itime)->GetLabel(ilab)) >= 0){
+          labelsall[nlabelsall++] = tindex;
+          ilab++;
+        }
+      }
+    }
+    Freq(nlab,labels,outlab,kFALSE);
+    Int_t   label     = outlab[0];
+    Int_t   frequency = outlab[1];
+    Freq(nlabelsall,labelsall,outlab,kFALSE);
+    Int_t   label1    = outlab[0];
+    Int_t   label2    = outlab[2];
+    Float_t fakeratio = (naccepted - outlab[1]) / Float_t(naccepted);
+
+    //Int_t eventNrInFile = esd->GetEventNumberInFile();
+    //AliInfo(Form("Number of clusters %d.", nclusters));
+    Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
+    Int_t trackNumber = AliTRDtrackerDebug::GetTrackNumber();
+    Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
+    TTreeSRedirector &cstreamer = *fgDebugStreamer;
+    cstreamer << "Clusters2TracksStack"
+        << "EventNumber="              << eventNumber
+        << "TrackNumber="              << trackNumber
+        << "CandidateNumber="  << candidateNumber
+        << "Iter="                             << fSieveSeeding
+        << "Like="                             << fTrackQuality[trackIndex]
+        << "S0.="                              << dseed[0]
+        << "S1.="                              << dseed[1]
+        << "S2.="                              << dseed[2]
+        << "S3.="                              << dseed[3]
+        << "S4.="                              << dseed[4]
+        << "S5.="                              << dseed[5]
+        << "p0="                               << trackParams[0]
+        << "p1="                               << trackParams[1]
+        << "p2="                               << trackParams[2]
+        << "p3="                               << trackParams[3]
+        << "p4="                               << trackParams[4]
+        << "p5="                               << trackParams[5]
+        << "p6="                               << trackParams[6]
+        << "Label="                            << label
+        << "Label1="                   << label1
+        << "Label2="                   << label2
+        << "FakeRatio="                        << fakeratio
+        << "Freq="                             << frequency
+        << "Ncl="                              << ncl
+        << "NLayers="                  << nlayers
+        << "Findable="                 << findable
+        << "NUsed="                            << nused
+        << "\n";
+  }
+      
+  AliTRDtrackV1 *track = MakeTrack(&sseed[trackIndex*kNPlanes], trackParams);
+  if(!track){
+    AliWarning("Fail to build a TRD Track.");
+    continue;
+  }
+
+  //AliInfo("End of MakeTrack()");
+  AliESDtrack *esdTrack = new ((*esdTrackList)[ntracks0++]) AliESDtrack();
+  esdTrack->UpdateTrackParams(track, AliESDtrack::kTRDout);
+  esdTrack->SetLabel(track->GetLabel());
+  track->UpdateESDtrack(esdTrack);
+  // write ESD-friends if neccessary
+  if (fReconstructor->GetStreamLevel(AliTRDReconstructor::kTracker) > 0){
+    AliTRDtrackV1 *calibTrack = new AliTRDtrackV1(*track);
+    calibTrack->SetOwner();
+    esdTrack->AddCalibObject(calibTrack);
+  }
+  ntracks1++;
+  AliTRDtrackerDebug::SetTrackNumber(AliTRDtrackerDebug::GetTrackNumber() + 1);
+      }
+
+      jSieve++;
+    } while(jSieve<5 && candidates); // end track candidates sieve
+    if(!ntracks1) break;
+
+    // increment counters
+    ntracks2 += ntracks1;
+
+    if(fReconstructor->IsHLT()) break;
+    fSieveSeeding++;
+
+    // Rebuild plane configurations and indices taking only unused clusters into account
+    quality = BuildSeedingConfigs(stack, configs);
+    if(quality < 1.E-7) break; //fReconstructor->GetRecoParam() ->GetPlaneQualityThreshold()) break;
+    
+    for(Int_t ip = 0; ip < kNPlanes; ip++){ 
+      if(!(chamber = stack[ip])) continue;
+      chamber->Build(fGeom, cal);//Indices(fSieveSeeding);
+    }
+
+    if(fReconstructor->GetStreamLevel(AliTRDReconstructor::kTracker) > 1){ 
+      AliInfo(Form("Sieve level %d Plane config %d %d %d Quality %f", fSieveSeeding, configs[0], configs[1], configs[2], quality));
+    }
+  } while(fSieveSeeding<10); // end stack clusters sieve
+  
 
 
-       //AliInfo(Form("Registered TRD tracks %d in stack %d.", ntracks2, pars[1]));
+  //AliInfo(Form("Registered TRD tracks %d in stack %d.", ntracks2, pars[1]));
 
-       return ntracks2;
+  return ntracks2;
 }
 
 //___________________________________________________________________
-Double_t AliTRDtrackerV1::BuildSeedingConfigs(AliTRDstackLayer *layers
-                                            , Int_t *configs)
+Double_t AliTRDtrackerV1::BuildSeedingConfigs(AliTRDtrackingChamber **stack, Int_t *configs)
 {
   //
   // Assign probabilities to chambers according to their
@@ -1372,28 +2172,31 @@ Double_t AliTRDtrackerV1::BuildSeedingConfigs(AliTRDstackLayer *layers
   // The overall chamber quality is given by the product of this 2 contributions.
   // 
 
-       Double_t chamberQA[kNPlanes];
-       for(int iplane=0; iplane<kNPlanes; iplane++){
-               chamberQA[iplane] = MakeSeedingPlanes(&layers[iplane*fTimeBinsPerPlane]);
-               //printf("chamberQA[%d] = %f\n", iplane, chamberQA[iplane]);
-       }
-
-       Double_t tconfig[kNConfigs];
-       Int_t planes[4];
-       for(int iconf=0; iconf<kNConfigs; iconf++){
-               GetSeedingConfig(iconf, planes);
-               tconfig[iconf] = fgTopologicQA[iconf];
-               for(int iplane=0; iplane<4; iplane++) tconfig[iconf] *= chamberQA[planes[iplane]]; 
-       }
-       
-       TMath::Sort(kNConfigs, tconfig, configs, kTRUE);
-       return tconfig[configs[0]];
+  Double_t chamberQ[kNPlanes];
+  AliTRDtrackingChamber *chamber = 0x0;
+  for(int iplane=0; iplane<kNPlanes; iplane++){
+    if(!(chamber = stack[iplane])) continue;
+    chamberQ[iplane] = (chamber = stack[iplane]) ?  chamber->GetQuality() : 0.;
+  }
+
+  Double_t tconfig[kNConfigs];
+  Int_t planes[4];
+  for(int iconf=0; iconf<kNConfigs; iconf++){
+    GetSeedingConfig(iconf, planes);
+    tconfig[iconf] = fgTopologicQA[iconf];
+    for(int iplane=0; iplane<4; iplane++) tconfig[iconf] *= chamberQ[planes[iplane]]; 
+  }
+  
+  TMath::Sort((Int_t)kNConfigs, tconfig, configs, kTRUE);
+  //   AliInfo(Form("q[%d] = %f", configs[0], tconfig[configs[0]]));
+  //   AliInfo(Form("q[%d] = %f", configs[1], tconfig[configs[1]]));
+  //   AliInfo(Form("q[%d] = %f", configs[2], tconfig[configs[2]]));
+  
+  return tconfig[configs[0]];
 }
 
 //____________________________________________________________________
-Int_t AliTRDtrackerV1::MakeSeeds(AliTRDstackLayer *layers
-                               , AliTRDseedV1 *sseed
-                               , Int_t *ipar)
+Int_t AliTRDtrackerV1::MakeSeeds(AliTRDtrackingChamber **stack, AliTRDseedV1 *sseed, Int_t *ipar)
 {
   //
   // Make tracklet seeds in the TRD stack.
@@ -1416,7 +2219,7 @@ Int_t AliTRDtrackerV1::MakeSeeds(AliTRDstackLayer *layers
   // 2. Select seeding clusters from the seeding AliTRDpropagationLayerStack.
   //   The clusters are taken from layer 3, layer 0, layer 1 and layer 2, in
   //   this order. The parameters controling the range of accepted clusters in
-  //   layer 0, 1, and 2 are defined in AliTRDstackLayer::BuildCond().
+  //   layer 0, 1, and 2 are defined in AliTRDchamberTimeBin::BuildCond().
   // 3. Helix fit of the cluster set. (see AliTRDtrackerFitter::FitRieman(AliTRDcluster**))
   // 4. Initialize seeding tracklets in the seeding chambers.
   // 5. Filter 0.
@@ -1444,357 +2247,336 @@ Int_t AliTRDtrackerV1::MakeSeeds(AliTRDstackLayer *layers
   // 15. Register seeds.
   //
 
-       AliTRDcluster *c[4] = {0x0, 0x0, 0x0, 0x0}; // initilize seeding clusters
-       AliTRDseedV1 *cseed = &sseed[0]; // initialize tracklets for first track
-       Int_t ncl, mcl; // working variable for looping over clusters
-       Int_t index[AliTRDstackLayer::kMaxClustersLayer], jndex[AliTRDstackLayer::kMaxClustersLayer];
-       // chi2 storage
-       // chi2[0] = tracklet chi2 on the Z direction
-       // chi2[1] = tracklet chi2 on the R direction
-       Double_t chi2[4];
+  AliTRDtrackingChamber *chamber = 0x0;
+  AliTRDcluster *c[kNSeedPlanes] = {0x0, 0x0, 0x0, 0x0}; // initilize seeding clusters
+  AliTRDseedV1 *cseed = &sseed[0]; // initialize tracklets for first track
+  Int_t ncl, mcl; // working variable for looping over clusters
+  Int_t index[AliTRDchamberTimeBin::kMaxClustersLayer], jndex[AliTRDchamberTimeBin::kMaxClustersLayer];
+  // chi2 storage
+  // chi2[0] = tracklet chi2 on the Z direction
+  // chi2[1] = tracklet chi2 on the R direction
+  Double_t chi2[4];
 
+       // Default positions for the anode wire in all 6 Layers in case of a stack with missing clusters
+       // Positions taken using cosmic data taken with SM3 after rebuild
+  Double_t x_def[kNPlanes] = {300.2, 312.8, 325.4, 338.0, 350.6, 363.2};
 
-       // this should be data member of AliTRDtrack
-       Double_t seedQuality[kMaxTracksStack];
-       
-       // unpack control parameters
-       Int_t config  = ipar[0];
-       Int_t istack  = ipar[1];
-       Int_t ntracks = ipar[2];
-       Int_t planes[kNSeedPlanes]; GetSeedingConfig(config, planes);   
-#ifdef DEBUG
-               if(AliTRDReconstructor::StreamLevel() > 1) AliInfo(Form("Making seeds Stack[%d] Config[%d] Tracks[%d]...", istack, config, ntracks));
-#endif
-       
-       // Init chambers geometry
-       Int_t det/*, tbRange[6]*/; // time bins inside the detector geometry
-       Double_t hL[kNPlanes];       // Tilting angle
-       Float_t padlength[kNPlanes]; // pad lenghts
-       AliTRDpadPlane *pp;
-       for(int il=0; il<kNPlanes; il++){
-               pp = fGeom->GetPadPlane(il, istack); // istack has to be imported
-               hL[il]        = TMath::Tan(-TMath::DegToRad()*pp->GetTiltingAngle());
-               padlength[il] = pp->GetLengthIPad();
-               det           = il; // to be fixed !!!!!
-               //tbRange[il]   = fTimeBinsPerPlane; //Int_t(AliTRDgeometry::CamHght()+AliTRDgeometry::CdrHght() * AliTRDCommonParam::Instance()->GetSamplingFrequency()/AliTRDcalibDB::Instance()->GetVdriftDet()->GetValue(det));
-               //printf("%d hl[%f] pl[%f] tb[%d]\n", il, hL[il], padlength[il], tbRange[il]);
-       }
-
-       Double_t cond0[4], cond1[4], cond2[4];
-       // make seeding layers (to be moved in Clusters2TracksStack)
-       AliTRDstackLayer *layer[] = {0x0, 0x0, 0x0, 0x0};
-       for(int isl=0; isl<kNSeedPlanes; isl++) layer[isl] = MakeSeedingLayer(&layers[planes[isl] * fTimeBinsPerPlane], planes[isl]);
-
-
-       // Start finding seeds
-       Int_t icl = 0;
-       while((c[3] = (*layer[3])[icl++])){
-               if(!c[3]) continue;
-               layer[0]->BuildCond(c[3], cond0, 0);
-               layer[0]->GetClusters(cond0, index, ncl);
-               Int_t jcl = 0;
-               while(jcl<ncl) {
-                       c[0] = (*layer[0])[index[jcl++]];
-                       if(!c[0]) continue;
-                       Double_t dx    = c[3]->GetX() - c[0]->GetX();
-                       Double_t theta = (c[3]->GetZ() - c[0]->GetZ())/dx;
-                       Double_t phi   = (c[3]->GetY() - c[0]->GetY())/dx;
-                       layer[1]->BuildCond(c[0], cond1, 1, theta, phi);
-                       layer[1]->GetClusters(cond1, jndex, mcl);
-
-                       Int_t kcl = 0;
-                       while(kcl<mcl) {
-                               c[1] = (*layer[1])[jndex[kcl++]];
-                               if(!c[1]) continue;
-                               layer[2]->BuildCond(c[1], cond2, 2, theta, phi);
-                               c[2] = layer[2]->GetNearestCluster(cond2);
-                               if(!c[2]) continue;
-                               
-                               //AliInfo("Seeding clusters found. Building seeds ...");
-                               //for(Int_t i = 0; i < kNSeedPlanes; i++) printf("%i. coordinates: x = %3.3f, y = %3.3f, z = %3.3f\n", i, c[i]->GetX(), c[i]->GetY(), c[i]->GetZ());
-                               for (Int_t il = 0; il < 6; il++) cseed[il].Reset();
-
-                               fFitter->Reset();
-
-                               fFitter->FitRieman(c, kNSeedPlanes);
-
-                               chi2[0] = 0.; chi2[1] = 0.;
-                               AliTRDseedV1 *tseed = 0x0;
-                               for(int iLayer=0; iLayer<kNSeedPlanes; iLayer++){
-                                       Int_t jLayer = planes[iLayer];
-                                       tseed = &cseed[jLayer];
-                                       tseed->SetRecoParam(fRecoParam);
-                                       tseed->SetPlane(jLayer);
-                                       tseed->SetTilt(hL[jLayer]);
-                                       tseed->SetPadLength(padlength[jLayer]);
-                                       //tseed->SetNTimeBinsRange(tbRange[jLayer]);
-                                       tseed->SetX0(layer[iLayer]->GetX());//layers[jLayer*fTimeBinsPerPlane].GetX());
-
-                                       tseed->Init(fFitter->GetRiemanFitter());
-                                       // temporary until new AttachClusters()
-                                       tseed->SetX0(layers[(jLayer+1)*fTimeBinsPerPlane-1].GetX());
-                                       chi2[0] += tseed->GetChi2Z(c[iLayer]->GetZ());
-                                       chi2[1] += tseed->GetChi2Y(c[iLayer]->GetY());
-                               }
-
-                               Bool_t isFake = kFALSE;
-                               if (c[0]->GetLabel(0) != c[3]->GetLabel(0)) isFake = kTRUE;
-                               if (c[1]->GetLabel(0) != c[3]->GetLabel(0)) isFake = kTRUE;
-                               if (c[2]->GetLabel(0) != c[3]->GetLabel(0)) isFake = kTRUE;
-#ifdef DEBUG
-                               if(AliTRDReconstructor::StreamLevel() >= 2){
-                                       Float_t yref[4], ycluster[4];
-                                       for(int il=0; il<4; il++){
-                                               tseed = &cseed[planes[il]];
-                                               yref[il] = tseed->GetYref(0);
-                                               ycluster[il] = c[il]->GetY();
-                                       }
-                                       Float_t threshold = .5;//1./(3. - sLayer);
-                                       Int_t ll = c[3]->GetLabel(0);
-                                       TTreeSRedirector &cs0 = *fDebugStreamer;
-                                                       cs0 << "MakeSeeds0"
-                                                       <<"isFake=" << isFake
-                                                       <<"label=" << ll
-                                                       <<"threshold=" << threshold
-                                                       <<"chi2=" << chi2[1]
-                                                       <<"yref0="<<yref[0]
-                                                       <<"yref1="<<yref[1]
-                                                       <<"yref2="<<yref[2]
-                                                       <<"yref3="<<yref[3]
-                                                       <<"ycluster0="<<ycluster[0]
-                                                       <<"ycluster1="<<ycluster[1]
-                                                       <<"ycluster2="<<ycluster[2]
-                                                       <<"ycluster3="<<ycluster[3]
-                                                       <<"\n";
-                               }
-#endif
-
-                               if(chi2[0] > fRecoParam->GetChi2Z()/*7./(3. - sLayer)*//*iter*/){
-                                       //AliInfo(Form("Failed chi2 filter on chi2Z [%f].", chi2[0]));
-                                       continue;
-                               }
-                               if(chi2[1] > fRecoParam->GetChi2Y()/*1./(3. - sLayer)*//*iter*/){
-                                       //AliInfo(Form("Failed chi2 filter on chi2Y [%f].", chi2[1]));
-                                       continue;
-                               }
-                               //AliInfo("Passed chi2 filter.");
-
-#ifdef DEBUG
-                               if(AliTRDReconstructor::StreamLevel() >= 2){
-                                       Float_t minmax[2] = { -100.0,  100.0 };
-                                       for (Int_t iLayer = 0; iLayer < 4; iLayer++) {
-                                               Float_t max = c[iLayer]->GetZ() + cseed[planes[iLayer]].GetPadLength() * 0.5 + 1.0 - cseed[planes[iLayer]].GetZref(0);
-                                               if (max < minmax[1]) minmax[1] = max;
-                                               Float_t min = c[iLayer]->GetZ()-cseed[planes[iLayer]].GetPadLength() * 0.5 - 1.0 - cseed[planes[iLayer]].GetZref(0);
-                                               if (min > minmax[0]) minmax[0] = min;
-                                       }
-                                       Double_t xpos[4];
-                                       for(Int_t l = 0; l < kNSeedPlanes; l++) xpos[l] = layer[l]->GetX();
-                                       TTreeSRedirector &cstreamer = *fDebugStreamer;
-                                                       cstreamer << "MakeSeeds1"
-                                               << "isFake=" << isFake
-                                               << "config="   << config
-                                               << "Cl0.="   << c[0]
-                                               << "Cl1.="   << c[1]
-                                               << "Cl2.="   << c[2]
-                                               << "Cl3.="   << c[3]
-                                               << "X0="     << xpos[0] //layer[sLayer]->GetX()
-                                               << "X1="     << xpos[1] //layer[sLayer + 1]->GetX()
-                                               << "X2="     << xpos[2] //layer[sLayer + 2]->GetX()
-                                               << "X3="     << xpos[3] //layer[sLayer + 3]->GetX()
-                                               << "Y2exp="  << cond2[0]
-                                               << "Z2exp="  << cond2[1]
-                                               << "Chi2R="  << chi2[0]
-                                               << "Chi2Z="  << chi2[1]
-                                               << "Seed0.=" << &cseed[planes[0]]
-                                               << "Seed1.=" << &cseed[planes[1]]
-                                               << "Seed2.=" << &cseed[planes[2]]
-                                               << "Seed3.=" << &cseed[planes[3]]
-                                               << "Zmin="   << minmax[0]
-                                               << "Zmax="   << minmax[1]
-                                               << "\n" ;
-                               }               
-#endif
-                               // try attaching clusters to tracklets
-                               Int_t nUsedCl = 0;
-                               Int_t nlayers = 0;
-                               for(int iLayer=0; iLayer<kNSeedPlanes; iLayer++){
-                                       Int_t jLayer = planes[iLayer];
-                                       if(!cseed[jLayer].AttachClustersIter(&layers[jLayer*fTimeBinsPerPlane], 5., kFALSE, c[iLayer])) continue;
-                                       nUsedCl += cseed[jLayer].GetNUsed();
-                                       if(nUsedCl > 25) break;
-                                       nlayers++;
-                               }
-                               if(nlayers < kNSeedPlanes){ 
-                                       //AliInfo("Failed updating all seeds.");
-                                       continue;
-                               }
-                               // fit tracklets and cook likelihood
-                               chi2[0] = 0.; chi2[1] = 0.;
-                               fFitter->FitRieman(&cseed[0], &planes[0]);
-                               AliRieman *rim = fFitter->GetRiemanFitter();
-                               for(int iLayer=0; iLayer<4; iLayer++){
-                                       cseed[planes[iLayer]].Init(rim);
-                                       chi2[0] += (Float_t)cseed[planes[iLayer]].GetChi2Z();
-                                       chi2[1] += cseed[planes[iLayer]].GetChi2Y();
-                               }
-                               Double_t chi2r = chi2[1], chi2z = chi2[0];
-                               Double_t like = CookLikelihood(&cseed[0], planes, chi2); // to be checked
-                               if (TMath::Log(1.E-9 + like) < fRecoParam->GetTrackLikelihood()){
-                                       //AliInfo(Form("Failed likelihood %f[%e].", TMath::Log(1.E-9 + like), like));
-                                       continue;
-                               }
-                               //AliInfo(Form("Passed likelihood %f[%e].", TMath::Log(1.E-9 + like), like));
-
-
-                               // book preliminary results
-                               seedQuality[ntracks] = like;
-                               fSeedLayer[ntracks]  = config;/*sLayer;*/
-
-                               // attach clusters to the extrapolation seeds
-                               Int_t lextrap[2];
-                               GetExtrapolationConfig(config, lextrap);
-                               Int_t nusedf   = 0; // debug value
-                               for(int iLayer=0; iLayer<2; iLayer++){
-                                       Int_t jLayer = lextrap[iLayer];
-                                       
-                                       // prepare extrapolated seed
-                                       cseed[jLayer].Reset();
-                                       cseed[jLayer].SetRecoParam(fRecoParam);
-                                       cseed[jLayer].SetPlane(jLayer);
-                                       cseed[jLayer].SetTilt(hL[jLayer]);
-                                       cseed[jLayer].SetX0(layers[(jLayer +1) * fTimeBinsPerPlane-1].GetX());
-                                       cseed[jLayer].SetPadLength(padlength[jLayer]);
-                                       //cseed[jLayer].SetNTimeBinsRange(tbRange[jLayer]);
-                                       cseed[jLayer].Init(rim);
-//                                     AliTRDcluster *cd = FindSeedingCluster(&layers[jLayer*fTimeBinsPerPlane], &cseed[jLayer]);
-//                                     if(cd == 0x0) continue;
-
-                                       // fit extrapolated seed
-                                       AliTRDseedV1::FitRiemanTilt(cseed, kTRUE);
-                                       if ((jLayer == 0) && !(cseed[1].IsOK())) continue;
-                                       if ((jLayer == 5) && !(cseed[4].IsOK())) continue;
-                                       AliTRDseedV1 tseed = cseed[jLayer];
-                                       if(!tseed.AttachClustersIter(&layers[jLayer*fTimeBinsPerPlane], 1000.)) continue;
-                                       cseed[jLayer] = tseed;
-                                       nusedf += cseed[jLayer].GetNUsed(); // debug value
-                                       AliTRDseedV1::FitRiemanTilt(cseed, kTRUE);
-                               }
-                               //AliInfo("Extrapolation done.");
-
-                               ImproveSeedQuality(layers, cseed);
-                               //AliInfo("Improve seed quality done.");
-
-                               nlayers   = 0;
-                               Int_t nclusters = 0;
-                               Int_t findable  = 0;
-                               for (Int_t iLayer = 0; iLayer < 6; iLayer++) {
-                                       if (TMath::Abs(cseed[iLayer].GetYref(0) / cseed[iLayer].GetX0()) < 0.15) findable++;
-                                       if (!cseed[iLayer].IsOK()) continue;
-                                       nclusters += cseed[iLayer].GetN2();
-                                       nlayers++;
-                               }
-                               if (nlayers < 3){ 
-                                       //AliInfo("Failed quality check on seeds.");
-                                       continue;
-                               }
-
-                               // fit full track and cook likelihoods
-                               fFitter->FitRieman(&cseed[0]);
-                               Double_t chi2ZF = 0., chi2RF = 0.;
-                               for(int ilayer=0; ilayer<6; ilayer++){
-                                       cseed[ilayer].Init(fFitter->GetRiemanFitter());
-                                       if (!cseed[ilayer].IsOK()) continue;
-                                       //tchi2 = cseed[ilayer].GetChi2Z();
-                                       //printf("layer %d chi2 %e\n", ilayer, tchi2);
-                                       chi2ZF += cseed[ilayer].GetChi2Z();
-                                       chi2RF += cseed[ilayer].GetChi2Y();
-                               }
-                               chi2ZF /= TMath::Max((nlayers - 3.), 1.);
-                               chi2RF /= TMath::Max((nlayers - 3.), 1.);
-
-                               // do the final track fitting
-                               fFitter->SetLayers(nlayers);
-#ifdef DEBUG
-                               fFitter->SetDebugStream(fDebugStreamer);
-#endif
-                               fTrackQuality[ntracks] = fFitter->FitHyperplane(&cseed[0], chi2ZF, GetZ());
-                               Double_t param[3];
-                               Double_t chi2[2];
-                               fFitter->GetHyperplaneFitResults(param);
-                               fFitter->GetHyperplaneFitChi2(chi2);
-                               //AliInfo("Hyperplane fit done\n");
-
-                               // finalize tracklets
-                               Int_t labels[12];
-                               Int_t outlab[24];
-                               Int_t nlab = 0;
-                               for (Int_t iLayer = 0; iLayer < 6; iLayer++) {
-                                       if (!cseed[iLayer].IsOK()) continue;
-
-                                       if (cseed[iLayer].GetLabels(0) >= 0) {
-                                               labels[nlab] = cseed[iLayer].GetLabels(0);
-                                               nlab++;
-                                       }
-
-                                       if (cseed[iLayer].GetLabels(1) >= 0) {
-                                               labels[nlab] = cseed[iLayer].GetLabels(1);
-                                               nlab++;
-                                       }
-                               }
-                               Freq(nlab,labels,outlab,kFALSE);
-                               Int_t label     = outlab[0];
-                               Int_t frequency = outlab[1];
-                               for (Int_t iLayer = 0; iLayer < 6; iLayer++) {
-                                       cseed[iLayer].SetFreq(frequency);
-                                       cseed[iLayer].SetC(param[1]/*cR*/);
-                                       cseed[iLayer].SetCC(param[0]/*cC*/);
-                                       cseed[iLayer].SetChi2(chi2[0]);
-                                       cseed[iLayer].SetChi2Z(chi2ZF);
-                               }
-           
-#ifdef DEBUG
-                               if(AliTRDReconstructor::StreamLevel() >= 2){
-                                       Double_t curv = (fFitter->GetRiemanFitter())->GetC();
-                                       TTreeSRedirector &cstreamer = *fDebugStreamer;
-                                       cstreamer << "MakeSeeds2"
-                                               << "C="       << curv
-                                               << "Chi2R="   << chi2r
-                                               << "Chi2Z="   << chi2z
-                                               << "Chi2TR="  << chi2[0]
-                                               << "Chi2TC="  << chi2[1]
-                                               << "Chi2RF="  << chi2RF
-                                               << "Chi2ZF="  << chi2ZF
-                                               << "Ncl="     << nclusters
-                                               << "Nlayers=" << nlayers
-                                               << "NUsedS="  << nUsedCl
-                                               << "NUsed="   << nusedf
-                                               << "Findable" << findable
-                                               << "Like="    << like
-                                               << "S0.="     << &cseed[0]
-                                               << "S1.="     << &cseed[1]
-                                               << "S2.="     << &cseed[2]
-                                               << "S3.="     << &cseed[3]
-                                               << "S4.="     << &cseed[4]
-                                               << "S5.="     << &cseed[5]
-                                               << "Label="   << label
-                                               << "Freq="    << frequency
-                                               << "\n";
-                               }
-#endif
-                               
-                               ntracks++;
-                               if(ntracks == kMaxTracksStack){
-                                       AliWarning(Form("Number of seeds reached maximum allowed (%d) in stack.", kMaxTracksStack));
-                                       return ntracks;
-                               }
-                               cseed += 6;
-                       }
-               }
-       }
-       for(int isl=0; isl<4; isl++) delete layer[isl];
-       
-       return ntracks;
+  // this should be data member of AliTRDtrack
+  Double_t seedQuality[kMaxTracksStack];
+  
+  // unpack control parameters
+  Int_t config  = ipar[0];
+  Int_t ntracks = ipar[1];
+  Int_t istack  = ipar[2];
+  Int_t planes[kNSeedPlanes]; GetSeedingConfig(config, planes);        
+  Int_t planesExt[kNPlanes-kNSeedPlanes];         GetExtrapolationConfig(config, planesExt);
+
+
+  // Init chambers geometry
+  Double_t hL[kNPlanes];       // Tilting angle
+  Float_t padlength[kNPlanes]; // pad lenghts
+  AliTRDpadPlane *pp = 0x0;
+  for(int iplane=0; iplane<kNPlanes; iplane++){
+    pp                = fGeom->GetPadPlane(iplane, istack);
+    hL[iplane]        = TMath::Tan(TMath::DegToRad()*pp->GetTiltingAngle());
+    padlength[iplane] = pp->GetLengthIPad();
+  }
+  
+  if(fReconstructor->GetStreamLevel(AliTRDReconstructor::kTracker) > 1){
+    AliInfo(Form("Making seeds Stack[%d] Config[%d] Tracks[%d]...", istack, config, ntracks));
+  }
+
+  // Build seeding layers
+  ResetSeedTB();
+  Int_t nlayers = 0;
+  for(int isl=0; isl<kNSeedPlanes; isl++){ 
+    if(!(chamber = stack[planes[isl]])) continue;
+    if(!chamber->GetSeedingLayer(fSeedTB[isl], fGeom, fReconstructor)) continue;
+    nlayers++;
+  }
+  if(nlayers < 4) return 0;
+  
+  
+  // Start finding seeds
+  Double_t cond0[4], cond1[4], cond2[4];
+  Int_t icl = 0;
+  while((c[3] = (*fSeedTB[3])[icl++])){
+    if(!c[3]) continue;
+    fSeedTB[0]->BuildCond(c[3], cond0, 0);
+    fSeedTB[0]->GetClusters(cond0, index, ncl);
+    //printf("Found c[3] candidates 0 %d\n", ncl);
+    Int_t jcl = 0;
+    while(jcl<ncl) {
+      c[0] = (*fSeedTB[0])[index[jcl++]];
+      if(!c[0]) continue;
+      Double_t dx    = c[3]->GetX() - c[0]->GetX();
+      Double_t theta = (c[3]->GetZ() - c[0]->GetZ())/dx;
+      Double_t phi   = (c[3]->GetY() - c[0]->GetY())/dx;
+      fSeedTB[1]->BuildCond(c[0], cond1, 1, theta, phi);
+      fSeedTB[1]->GetClusters(cond1, jndex, mcl);
+      //printf("Found c[0] candidates 1 %d\n", mcl);
+
+      Int_t kcl = 0;
+      while(kcl<mcl) {
+        c[1] = (*fSeedTB[1])[jndex[kcl++]];
+        if(!c[1]) continue;
+        fSeedTB[2]->BuildCond(c[1], cond2, 2, theta, phi);
+        c[2] = fSeedTB[2]->GetNearestCluster(cond2);
+        //printf("Found c[1] candidate 2 %p\n", c[2]);
+        if(!c[2]) continue;
+              
+        //                             AliInfo("Seeding clusters found. Building seeds ...");
+        //                             for(Int_t i = 0; i < kNSeedPlanes; i++) printf("%i. coordinates: x = %6.3f, y = %6.3f, z = %6.3f\n", i, c[i]->GetX(), c[i]->GetY(), c[i]->GetZ());
+              
+        for (Int_t il = 0; il < kNPlanes; il++) cseed[il].Reset();
+      
+        FitRieman(c, chi2);
+      
+        AliTRDseedV1 *tseed = &cseed[0];
+        AliTRDtrackingChamber **cIter = &stack[0];
+        for(int iLayer=0; iLayer<kNPlanes; iLayer++, tseed++, cIter++){
+          tseed->SetDetector((*cIter) ? (*cIter)->GetDetector() : -1);
+          tseed->SetTilt(hL[iLayer]);
+          tseed->SetPadLength(padlength[iLayer]);
+          tseed->SetReconstructor(fReconstructor);
+          tseed->SetX0((*cIter) ? (*cIter)->GetX() : x_def[iLayer]);
+          tseed->Init(GetRiemanFitter());
+        }
+      
+        Bool_t isFake = kFALSE;
+        if(fReconstructor->GetStreamLevel(AliTRDReconstructor::kTracker) >= 2){
+          if (c[0]->GetLabel(0) != c[3]->GetLabel(0)) isFake = kTRUE;
+          if (c[1]->GetLabel(0) != c[3]->GetLabel(0)) isFake = kTRUE;
+          if (c[2]->GetLabel(0) != c[3]->GetLabel(0)) isFake = kTRUE;
+      
+          Double_t xpos[4];
+          for(Int_t l = 0; l < kNSeedPlanes; l++) xpos[l] = fSeedTB[l]->GetX();
+          Float_t yref[4];
+          for(int il=0; il<4; il++) yref[il] = cseed[planes[il]].GetYref(0);
+          Int_t ll = c[3]->GetLabel(0);
+          Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
+          Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
+          AliRieman *rim = GetRiemanFitter();
+          TTreeSRedirector &cs0 = *fgDebugStreamer;
+          cs0 << "MakeSeeds0"
+              <<"EventNumber="         << eventNumber
+              <<"CandidateNumber="     << candidateNumber
+              <<"isFake="                              << isFake
+              <<"config="                              << config
+              <<"label="                               << ll
+              <<"chi2z="                               << chi2[0]
+              <<"chi2y="                               << chi2[1]
+              <<"Y2exp="                               << cond2[0]     
+              <<"Z2exp="                               << cond2[1]
+              <<"X0="                                  << xpos[0] //layer[sLayer]->GetX()
+              <<"X1="                                  << xpos[1] //layer[sLayer + 1]->GetX()
+              <<"X2="                                  << xpos[2] //layer[sLayer + 2]->GetX()
+              <<"X3="                                  << xpos[3] //layer[sLayer + 3]->GetX()
+              <<"yref0="                               << yref[0]
+              <<"yref1="                               << yref[1]
+              <<"yref2="                               << yref[2]
+              <<"yref3="                               << yref[3]
+              <<"c0.="                         << c[0]
+              <<"c1.="                         << c[1]
+              <<"c2.="                         << c[2]
+              <<"c3.="                         << c[3]
+              <<"Seed0.="                              << &cseed[planes[0]]
+              <<"Seed1.="                              << &cseed[planes[1]]
+              <<"Seed2.="                              << &cseed[planes[2]]
+              <<"Seed3.="                              << &cseed[planes[3]]
+              <<"RiemanFitter.="               << rim
+              <<"\n";
+        }
+        if(chi2[0] > fReconstructor->GetRecoParam() ->GetChi2Z()/*7./(3. - sLayer)*//*iter*/){
+//          //AliInfo(Form("Failed chi2 filter on chi2Z [%f].", chi2[0]));
+          AliTRDtrackerDebug::SetCandidateNumber(AliTRDtrackerDebug::GetCandidateNumber() + 1);
+          continue;
+        }
+        if(chi2[1] > fReconstructor->GetRecoParam() ->GetChi2Y()/*1./(3. - sLayer)*//*iter*/){
+//          //AliInfo(Form("Failed chi2 filter on chi2Y [%f].", chi2[1]));
+          AliTRDtrackerDebug::SetCandidateNumber(AliTRDtrackerDebug::GetCandidateNumber() + 1);
+          continue;
+        }
+        //AliInfo("Passed chi2 filter.");
+      
+        // try attaching clusters to tracklets
+        Int_t nUsedCl = 0;
+        Int_t mlayers = 0;
+        for(int iLayer=0; iLayer<kNSeedPlanes; iLayer++){
+          Int_t jLayer = planes[iLayer];
+          if(!cseed[jLayer].AttachClustersIter(stack[jLayer], 5., kFALSE, c[iLayer])) continue;
+          nUsedCl += cseed[jLayer].GetNUsed();
+          if(nUsedCl > 25) break;
+          mlayers++;
+        }
+
+        if(mlayers < kNSeedPlanes){ 
+          //AliInfo(Form("Failed updating all seeds %d [%d].", mlayers, kNSeedPlanes));
+          AliTRDtrackerDebug::SetCandidateNumber(AliTRDtrackerDebug::GetCandidateNumber() + 1);
+          continue;
+        }
+
+        // temporary exit door for the HLT
+        if(fReconstructor->IsHLT()){ 
+          // attach clusters to extrapolation chambers
+          for(int iLayer=0; iLayer<kNPlanes-kNSeedPlanes; iLayer++){
+            Int_t jLayer = planesExt[iLayer];
+            if(!(chamber = stack[jLayer])) continue;
+            cseed[jLayer].AttachClustersIter(chamber, 1000.);
+          }
+          fTrackQuality[ntracks] = 1.; // dummy value
+          ntracks++;
+          if(ntracks == kMaxTracksStack) return ntracks;
+          cseed += 6; 
+          continue;
+        }
+
+
+        // fit tracklets and cook likelihood
+        FitTiltedRieman(&cseed[0], kTRUE);// Update Seeds and calculate Likelihood
+        Double_t like = CookLikelihood(&cseed[0], planes); // to be checked
+      
+        if (TMath::Log(1.E-9 + like) < fReconstructor->GetRecoParam() ->GetTrackLikelihood()){
+          //AliInfo(Form("Failed likelihood %f[%e].", TMath::Log(1.E-9 + like), like));
+          AliTRDtrackerDebug::SetCandidateNumber(AliTRDtrackerDebug::GetCandidateNumber() + 1);
+          continue;
+        }
+        //AliInfo(Form("Passed likelihood %f[%e].", TMath::Log(1.E-9 + like), like));
+      
+        // book preliminary results
+        seedQuality[ntracks] = like;
+        fSeedLayer[ntracks]  = config;/*sLayer;*/
+      
+        // attach clusters to the extrapolation seeds
+        Int_t nusedf   = 0; // debug value
+        for(int iLayer=0; iLayer<kNPlanes-kNSeedPlanes; iLayer++){
+          Int_t jLayer = planesExt[iLayer];
+          if(!(chamber = stack[jLayer])) continue;
+      
+          // fit extrapolated seed
+          if ((jLayer == 0) && !(cseed[1].IsOK())) continue;
+          if ((jLayer == 5) && !(cseed[4].IsOK())) continue;
+          AliTRDseedV1 pseed = cseed[jLayer];
+          if(!pseed.AttachClustersIter(chamber, 1000.)) continue;
+          cseed[jLayer] = pseed;
+          nusedf += cseed[jLayer].GetNUsed(); // debug value
+          FitTiltedRieman(cseed,  kTRUE);
+        }
+      
+        // AliInfo("Extrapolation done.");
+        // Debug Stream containing all the 6 tracklets
+        if(fReconstructor->GetStreamLevel(AliTRDReconstructor::kTracker) >= 2){
+          TTreeSRedirector &cstreamer = *fgDebugStreamer;
+          TLinearFitter *tiltedRieman = GetTiltedRiemanFitter();
+          Int_t eventNumber            = AliTRDtrackerDebug::GetEventNumber();
+          Int_t candidateNumber        = AliTRDtrackerDebug::GetCandidateNumber();
+          cstreamer << "MakeSeeds1"
+              << "EventNumber="                << eventNumber
+              << "CandidateNumber="    << candidateNumber
+              << "S0.="                                << &cseed[0]
+              << "S1.="                                << &cseed[1]
+              << "S2.="                                << &cseed[2]
+              << "S3.="                                << &cseed[3]
+              << "S4.="                                << &cseed[4]
+              << "S5.="                                << &cseed[5]
+              << "FitterT.="                   << tiltedRieman
+              << "\n";
+        }
+              
+        if(fReconstructor->GetRecoParam()->HasImproveTracklets() && ImproveSeedQuality(stack, cseed) < 4){
+          AliTRDtrackerDebug::SetCandidateNumber(AliTRDtrackerDebug::GetCandidateNumber() + 1);
+          continue;
+        }
+        //AliInfo("Improve seed quality done.");
+      
+        // fit full track and cook likelihoods
+        //                             Double_t curv = FitRieman(&cseed[0], chi2);
+        //                             Double_t chi2ZF = chi2[0] / TMath::Max((mlayers - 3.), 1.);
+        //                             Double_t chi2RF = chi2[1] / TMath::Max((mlayers - 3.), 1.);
+      
+        // do the final track fitting (Once with vertex constraint and once without vertex constraint)
+        Double_t chi2Vals[3];
+        chi2Vals[0] = FitTiltedRieman(&cseed[0], kFALSE);
+        if(fReconstructor->GetRecoParam()->IsVertexConstrained())
+          chi2Vals[1] = FitTiltedRiemanConstraint(&cseed[0], GetZ()); // Do Vertex Constrained fit if desired
+        else
+          chi2Vals[1] = 1.;
+        chi2Vals[2] = GetChi2Z(&cseed[0]) / TMath::Max((mlayers - 3.), 1.);
+        // Chi2 definitions in testing stage
+        //chi2Vals[2] = GetChi2ZTest(&cseed[0]);
+        fTrackQuality[ntracks] = CalculateTrackLikelihood(&cseed[0], &chi2Vals[0]);
+        //AliInfo("Hyperplane fit done\n");
+      
+        // finalize tracklets
+        Int_t labels[12];
+        Int_t outlab[24];
+        Int_t nlab = 0;
+        for (Int_t iLayer = 0; iLayer < 6; iLayer++) {
+          if (!cseed[iLayer].IsOK()) continue;
+      
+          if (cseed[iLayer].GetLabels(0) >= 0) {
+            labels[nlab] = cseed[iLayer].GetLabels(0);
+            nlab++;
+          }
+      
+          if (cseed[iLayer].GetLabels(1) >= 0) {
+            labels[nlab] = cseed[iLayer].GetLabels(1);
+            nlab++;
+          }
+        }
+        Freq(nlab,labels,outlab,kFALSE);
+        Int_t label     = outlab[0];
+        Int_t frequency = outlab[1];
+        for (Int_t iLayer = 0; iLayer < 6; iLayer++) {
+          cseed[iLayer].SetFreq(frequency);
+          cseed[iLayer].SetChi2Z(chi2[1]);
+        }
+            
+        if(fReconstructor->GetStreamLevel(AliTRDReconstructor::kTracker) >= 2){
+          TTreeSRedirector &cstreamer = *fgDebugStreamer;
+          Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
+          Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
+          TLinearFitter *fitterTC = GetTiltedRiemanFitterConstraint();
+          TLinearFitter *fitterT = GetTiltedRiemanFitter();
+          Int_t ncls = 0; 
+          for(Int_t iseed = 0; iseed < kNPlanes; iseed++){
+               ncls += cseed[iseed].IsOK() ? cseed[iseed].GetN2() : 0;
+          }
+          cstreamer << "MakeSeeds2"
+              << "EventNumber="                << eventNumber
+              << "CandidateNumber="    << candidateNumber
+              << "Chi2TR="                     << chi2Vals[0]
+              << "Chi2TC="                     << chi2Vals[1]
+              << "Nlayers="                    << mlayers
+              << "NClusters="   << ncls
+              << "NUsedS="                     << nUsedCl
+              << "NUsed="                              << nusedf
+              << "Like="                               << like
+              << "S0.="                                << &cseed[0]
+              << "S1.="                                << &cseed[1]
+              << "S2.="                                << &cseed[2]
+              << "S3.="                                << &cseed[3]
+              << "S4.="                                << &cseed[4]
+              << "S5.="                                << &cseed[5]
+              << "Label="                              << label
+              << "Freq="                               << frequency
+              << "FitterT.="                   << fitterT
+              << "FitterTC.="                  << fitterTC
+              << "\n";
+        }
+              
+        ntracks++;
+        AliTRDtrackerDebug::SetCandidateNumber(AliTRDtrackerDebug::GetCandidateNumber() + 1);
+        if(ntracks == kMaxTracksStack){
+          AliWarning(Form("Number of seeds reached maximum allowed (%d) in stack.", kMaxTracksStack));
+          return ntracks;
+        }
+        cseed += 6;
+      }
+    }
+  }
+  
+  return ntracks;
 }
 
 //_____________________________________________________________________________
@@ -1815,6 +2597,7 @@ AliTRDtrackV1* AliTRDtrackerV1::MakeTrack(AliTRDseedV1 *seeds, Double_t *params)
   // To be discussed with Marian !!
   //
 
+
   Double_t alpha = AliTRDgeometry::GetAlpha();
   Double_t shift = AliTRDgeometry::GetAlpha()/2.0;
   Double_t c[15];
@@ -1825,32 +2608,64 @@ AliTRDtrackV1* AliTRDtrackerV1::MakeTrack(AliTRDseedV1 *seeds, Double_t *params)
   c[ 6] = 0.0; c[ 7] = 0.0; c[ 8] = 0.0;  c[ 9] = 0.1;
   c[10] = 0.0; c[11] = 0.0; c[12] = 0.0;  c[13] = 0.0; c[14] = params[5]*params[5]*0.01;
 
-  AliTRDtrackV1 *track = new AliTRDtrackV1(seeds, &params[1], c, params[0], params[6]*alpha+shift);
-       track->PropagateTo(params[0]-5.0);
-  track->ResetCovariance(1);
-  Int_t nc = FollowBackProlongation(*track);
-       AliInfo(Form("N clusters for track %d", nc));
-       if (nc < 30) {
-    delete track;
-    track = 0x0;
-  } else {
-//     track->CookdEdx();
-//     track->CookdEdxTimBin(-1);
-//     CookLabel(track, 0.9);
+  AliTRDtrackV1 track(seeds, &params[1], c, params[0], params[6]*alpha+shift);
+  track.PropagateTo(params[0]-5.0);
+  if(fReconstructor->IsHLT()){ 
+    AliTRDseedV1 *ptrTracklet = 0x0;
+    for(Int_t ip=0; ip<kNPlanes; ip++){
+      track.UnsetTracklet(ip);
+      ptrTracklet = SetTracklet(&seeds[ip]);
+      track.SetTracklet(ptrTracklet, fTracklets->GetEntriesFast()-1);
+    }
+    return SetTrack(&track);
   }
 
-  return track;
-}
+  track.ResetCovariance(1);
+  Int_t nc = TMath::Abs(FollowBackProlongation(track));
+  if(fReconstructor->GetStreamLevel(AliTRDReconstructor::kTracker) > 5){
+    Int_t eventNumber          = AliTRDtrackerDebug::GetEventNumber();
+    Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
+    Double_t p[5]; // Track Params for the Debug Stream
+    track.GetExternalParameters(params[0], p);
+    TTreeSRedirector &cs = *fgDebugStreamer;
+    cs << "MakeTrack"
+    << "EventNumber="     << eventNumber
+    << "CandidateNumber=" << candidateNumber
+    << "nc="     << nc
+    << "X="      << params[0]
+    << "Y="      << p[0]
+    << "Z="      << p[1]
+    << "snp="    << p[2]
+    << "tnd="    << p[3]
+    << "crv="    << p[4]
+    << "Yin="    << params[1]
+    << "Zin="    << params[2]
+    << "snpin="  << params[3]
+    << "tndin="  << params[4]
+    << "crvin="  << params[5]
+    << "track.=" << &track
+    << "\n";
+  }
+  if (nc < 30) return 0x0;
 
-//____________________________________________________________________
-void AliTRDtrackerV1::CookLabel(AliKalmanTrack */*pt*/, Float_t /*wrong*/) const
-{
-       // to be implemented, preferably at the level of TRD tracklet. !!!!!!!
+  AliTRDtrackV1 *ptrTrack = SetTrack(&track);
+  ptrTrack->SetReconstructor(fReconstructor);
+  ptrTrack->CookLabel(.9);
+  
+  // computes PID for track
+  ptrTrack->CookPID();
+  // update calibration references using this track
+  AliTRDCalibraFillHisto *calibra = AliTRDCalibraFillHisto::Instance();
+  if (!calibra){ 
+    AliInfo("Could not get Calibra instance\n");
+    if(calibra->GetHisto2d()) calibra->UpdateHistogramsV1(ptrTrack);
+  }
+  return ptrTrack;
 }
 
+
 //____________________________________________________________________
-void AliTRDtrackerV1::ImproveSeedQuality(AliTRDstackLayer *layers
-                                       , AliTRDseedV1 *cseed)
+Int_t AliTRDtrackerV1::ImproveSeedQuality(AliTRDtrackingChamber **stack, AliTRDseedV1 *cseed)
 {
   //
   // Sort tracklets according to "quality" and try to "improve" the first 4 worst
@@ -1868,109 +2683,123 @@ void AliTRDtrackerV1::ImproveSeedQuality(AliTRDstackLayer *layers
   // tracklet seed such that the seed quality (see AliTRDseed::GetQuality())
   // can be maximized. If some optimization is found the old seeds are replaced.
   //
-       
-       AliTRDcalibDB *cal = AliTRDcalibDB::Instance();
-       Int_t nTimeBins = cal->GetNumberOfTimeBins();
-       
-       // make a local working copy
-       AliTRDseedV1 bseed[6];
-       for (Int_t jLayer = 0; jLayer < 6; jLayer++) bseed[jLayer] = cseed[jLayer];
-
-
-       Float_t lastquality = 10000.0;
-       Float_t lastchi2    = 10000.0;
-       Float_t chi2        =  1000.0;
-
-       for (Int_t iter = 0; iter < 4; iter++) {
-               Float_t sumquality = 0.0;
-               Float_t squality[6];
-               Int_t   sortindexes[6];
-
-               for (Int_t jLayer = 0; jLayer < 6; jLayer++) {
-                       squality[jLayer]  = bseed[jLayer].IsOK() ? bseed[jLayer].GetQuality(kTRUE) : -1.;
-                       sumquality +=squality[jLayer];
-               }
-               if ((sumquality >= lastquality) || (chi2       >     lastchi2)) break;
-
-               
-               lastquality = sumquality;
-               lastchi2    = chi2;
-               if (iter > 0) for (Int_t jLayer = 0; jLayer < 6; jLayer++) cseed[jLayer] = bseed[jLayer];
-
-               
-               TMath::Sort(6, squality, sortindexes, kFALSE);
-               for (Int_t jLayer = 5; jLayer > 1; jLayer--) {
-                       Int_t bLayer = sortindexes[jLayer];
-                       bseed[bLayer].AttachClustersIter(&layers[bLayer*nTimeBins], squality[bLayer], kTRUE);
-               }
-
-               chi2 = AliTRDseedV1::FitRiemanTilt(bseed,kTRUE);
-       } // Loop: iter
+  // debug level: 7
+  //
+  
+  // make a local working copy
+  AliTRDtrackingChamber *chamber = 0x0;
+  AliTRDseedV1 bseed[6];
+  Int_t nLayers = 0;
+  for (Int_t jLayer = 0; jLayer < 6; jLayer++) bseed[jLayer] = cseed[jLayer];
+  
+  Float_t lastquality = 10000.0;
+  Float_t lastchi2    = 10000.0;
+  Float_t chi2        =  1000.0;
+
+  for (Int_t iter = 0; iter < 4; iter++) {
+    Float_t sumquality = 0.0;
+    Float_t squality[6];
+    Int_t   sortindexes[6];
+
+    for (Int_t jLayer = 0; jLayer < 6; jLayer++) {
+      squality[jLayer]  = bseed[jLayer].IsOK() ? bseed[jLayer].GetQuality(kTRUE) : 1000.;
+      sumquality += squality[jLayer];
+    }
+    if ((sumquality >= lastquality) || (chi2       >     lastchi2)) break;
+
+    nLayers = 0;
+    lastquality = sumquality;
+    lastchi2    = chi2;
+    if (iter > 0) for (Int_t jLayer = 0; jLayer < 6; jLayer++) cseed[jLayer] = bseed[jLayer];
+
+    TMath::Sort(6, squality, sortindexes, kFALSE);
+    for (Int_t jLayer = 5; jLayer > 1; jLayer--) {
+      Int_t bLayer = sortindexes[jLayer];
+      if(!(chamber = stack[bLayer])) continue;
+      bseed[bLayer].AttachClustersIter(chamber, squality[bLayer], kTRUE);
+      if(bseed[bLayer].IsOK()) nLayers++;
+    }
+
+    chi2 = FitTiltedRieman(bseed, kTRUE);
+    if(fReconstructor->GetStreamLevel(AliTRDReconstructor::kTracker) >= 7){
+      Int_t eventNumber                = AliTRDtrackerDebug::GetEventNumber();
+      Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
+      TLinearFitter *tiltedRieman = GetTiltedRiemanFitter();
+      TTreeSRedirector &cstreamer = *fgDebugStreamer;
+      cstreamer << "ImproveSeedQuality"
+    << "EventNumber="          << eventNumber
+    << "CandidateNumber="      << candidateNumber
+    << "Iteration="                            << iter
+    << "S0.="                                                  << &bseed[0]
+    << "S1.="                                                  << &bseed[1]
+    << "S2.="                                                  << &bseed[2]
+    << "S3.="                                                  << &bseed[3]
+    << "S4.="                                                  << &bseed[4]
+    << "S5.="                                                  << &bseed[5]
+    << "FitterT.="                             << tiltedRieman
+    << "\n";
+    }
+  } // Loop: iter
+  
+  // we are sure that at least 2 tracklets are OK !
+  return nLayers+2;
 }
 
-//____________________________________________________________________
-Double_t  AliTRDtrackerV1::MakeSeedingPlanes(AliTRDstackLayer *layers)
-{
+//_________________________________________________________________________
+Double_t AliTRDtrackerV1::CalculateTrackLikelihood(AliTRDseedV1 *tracklets, Double_t *chi2){
   //
-  // Calculate plane quality for seeding.
-  // 
+  // Calculates the Track Likelihood value. This parameter serves as main quality criterion for 
+  // the track selection
+  // The likelihood value containes:
+  //    - The chi2 values from the both fitters and the chi2 values in z-direction from a linear fit
+  //    - The Sum of the Parameter  |slope_ref - slope_fit|/Sigma of the tracklets
+  // For all Parameters an exponential dependency is used
   //
-  // Parameters :
-  //   layers : Array of propagation layers for this plane.
+  // Parameters: - Array of tracklets (AliTRDseedV1) related to the track candidate
+  //             - Array of chi2 values: 
+  //                 * Non-Constrained Tilted Riemann fit
+  //                 * Vertex-Constrained Tilted Riemann fit
+  //                 * z-Direction from Linear fit
+  // Output:     - The calculated track likelihood
   //
-  // Output :
-  //   plane quality factor for seeding
-  // 
-  // Detailed description
+  // debug level 2
   //
-  // The quality of the plane for seeding is higher if:
-  //  1. the average timebin population is closer to an integer number
-  //  2. the distribution of clusters/timebin is closer to a uniform distribution.
-  //    - the slope of the first derivative of a parabolic fit is small or
-  //    - the slope of a linear fit is small
-  //
-
-       AliTRDcalibDB *cal = AliTRDcalibDB::Instance();
-       Int_t nTimeBins = cal->GetNumberOfTimeBins();
-
-//     Double_t x;
-//     TLinearFitter fitter(1, "pol1");
-//     fitter.ClearPoints();
-       Int_t ncl = 0;
-       Int_t nused = 0;
-       Int_t nClLayer;
-       for(int itb=0; itb<nTimeBins; itb++){
-               //x = layer[itb].GetX();
-               //printf("x[%d] = %f nCls %d\n", itb, x, layer[itb].GetNClusters());
-               //if(!layer[itb].GetNClusters()) continue;
-               //fitter.AddPoint(&x, layer[itb].GetNClusters(), 1.);
-               nClLayer = layers[itb].GetNClusters();
-               ncl += nClLayer;
-               for(Int_t incl = 0; incl < nClLayer; incl++)
-                       if((layers[itb].GetCluster(incl))->IsUsed()) nused++;
-       }
-       
-       // calculate the deviation of the mean number of clusters from the
-       // closest integer values
-       Float_t nclMed = float(ncl-nused)/nTimeBins;
-       Int_t ncli = Int_t(nclMed);
-       Float_t nclDev = TMath::Abs(nclMed - TMath::Max(ncli, 1));
-       nclDev -= (nclDev>.5) && ncli ? 0. : 1.; 
-       /*Double_t quality = */ return TMath::Exp(2.*nclDev);
-
-//     // get slope of the derivative
-//     if(!fitter.Eval()) return quality;
-//     fitter.PrintResults(3);
-//     Double_t a = fitter.GetParameter(1);
-// 
-//     printf("ncl_dev(%f)  a(%f)\n", ncl_dev, a);
-//     return quality*TMath::Exp(-a);
+
+  Double_t sumdaf = 0, nLayers = 0;
+  for (Int_t iLayer = 0; iLayer < kNPlanes; iLayer++) {
+    if(!tracklets[iLayer].IsOK()) continue;
+    sumdaf += TMath::Abs((tracklets[iLayer].GetYfit(1) - tracklets[iLayer].GetYref(1))/ tracklets[iLayer].GetSigmaY2());
+    nLayers++;
+  }
+  sumdaf /= Float_t (nLayers - 2.0);
+  
+  Double_t likeChi2Z  = TMath::Exp(-chi2[2] * 0.14);                   // Chi2Z 
+  Double_t likeChi2TC = (fReconstructor->GetRecoParam() ->IsVertexConstrained()) ? 
+                                                                                       TMath::Exp(-chi2[1] * 0.677) : 1;                       // Constrained Tilted Riemann
+  Double_t likeChi2TR = TMath::Exp(-chi2[0] * 0.78);                   // Non-constrained Tilted Riemann
+  Double_t likeAF     = TMath::Exp(-sumdaf * 3.23);
+  Double_t trackLikelihood     = likeChi2Z * likeChi2TR * likeAF;
+
+  if(fReconstructor->GetStreamLevel(AliTRDReconstructor::kTracker) >= 2){
+    Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
+    Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
+    TTreeSRedirector &cstreamer = *fgDebugStreamer;
+    cstreamer << "CalculateTrackLikelihood0"
+        << "EventNumber="                      << eventNumber
+        << "CandidateNumber="  << candidateNumber
+        << "LikeChi2Z="                                << likeChi2Z
+        << "LikeChi2TR="                       << likeChi2TR
+        << "LikeChi2TC="                       << likeChi2TC
+        << "LikeAF="                                   << likeAF
+        << "TrackLikelihood=" << trackLikelihood
+        << "\n";
+  }
+
+  return trackLikelihood;
 }
 
 //____________________________________________________________________
-Double_t AliTRDtrackerV1::CookLikelihood(AliTRDseedV1 *cseed
-                                       , Int_t planes[4]
-                                       , Double_t *chi2)
+Double_t AliTRDtrackerV1::CookLikelihood(AliTRDseedV1 *cseed, Int_t planes[4])
 {
   //
   // Calculate the probability of this track candidate.
@@ -1995,435 +2824,68 @@ Double_t AliTRDtrackerV1::CookLikelihood(AliTRDseedV1 *cseed
   // The distributions for each type of probabilities are given below as of
   // (date). They have to be checked to assure consistency of estimation.
   //
-       AliTRDcalibDB *cal = AliTRDcalibDB::Instance();
-       Int_t nTimeBins = cal->GetNumberOfTimeBins();
-       // ratio of the total number of clusters/track which are expected to be found by the tracker.
-       Float_t fgFindable = fRecoParam->GetFindableClusters();
-
-       
-       Int_t nclusters = 0;
-       Double_t sumda = 0.;
-       for(UChar_t ilayer = 0; ilayer < 4; ilayer++){
-               Int_t jlayer = planes[ilayer];
-               nclusters += cseed[jlayer].GetN2();
-               sumda += TMath::Abs(cseed[jlayer].GetYfitR(1) - cseed[jlayer].GetYref(1));
-       }
-       Double_t likea     = TMath::Exp(-sumda*10.6);
-       Double_t likechi2y  = 0.0000000001;
-       if (chi2[1] < 0.5) likechi2y += TMath::Exp(-TMath::Sqrt(chi2[1]) * 7.73);
-       Double_t likechi2z = TMath::Exp(-chi2[0] * 0.088) / TMath::Exp(-chi2[0] * 0.019);
-       Int_t enc = Int_t(fgFindable*4.*nTimeBins);     // Expected Number Of Clusters, normally 72
-       Double_t likeN     = TMath::Exp(-(enc - nclusters) * 0.19);
-       
-       Double_t like      = likea * likechi2y * likechi2z * likeN;
-
-#ifdef DEBUG
-       //AliInfo(Form("sumda(%f) chi2[0](%f) chi2[1](%f) likea(%f) likechi2y(%f) likechi2z(%f) nclusters(%d) likeN(%f)", sumda, chi2[0], chi2[1], likea, likechi2y, likechi2z, nclusters, likeN));
-       if(AliTRDReconstructor::StreamLevel() >= 2){
-               TTreeSRedirector &cstreamer = *fDebugStreamer;
-               cstreamer << "CookLikelihood"
-                       << "sumda="     << sumda
-                       << "chi0="      << chi2[0]
-                       << "chi1="      << chi2[1]
-                       << "likea="     << likea
-                       << "likechi2y=" << likechi2y
-                       << "likechi2z=" << likechi2z
-                       << "nclusters=" << nclusters
-                       << "likeN="     << likeN
-                       << "like="      << like
-                       << "\n";
-       }
-#endif
-
-       return like;
-}
-
-//___________________________________________________________________
-void AliTRDtrackerV1::GetMeanCLStack(AliTRDstackLayer *layers
-                                   , Int_t *planes
-                                   , Double_t *params)
-{
-  //
-  // Determines the Mean number of clusters per layer.
-  // Needed to determine good Seeding Layers
-  //
-  // Parameters:
-  //    - Array of AliTRDstackLayers
-  //    - Container for the params
-  //
-  // Detailed description
-  //
-  // Two Iterations:
-  // In the first Iteration the mean is calculted using all layers.
-  // After this, all layers outside the 1-sigma-region are rejected.
-  // Then the mean value and the standard-deviation are calculted a second
-  // time in order to select all layers in the 1-sigma-region as good-candidates.
-  //
-
-       AliTRDcalibDB *cal = AliTRDcalibDB::Instance();
-       Int_t nTimeBins = cal->GetNumberOfTimeBins();
-       
-       Float_t mean = 0, stdev = 0;
-       Double_t ncl[kNTimeBins*kNSeedPlanes], mcl[kNTimeBins*kNSeedPlanes];
-       Int_t position = 0;
-       memset(ncl, 0, sizeof(Int_t)*kNTimeBins*kNSeedPlanes);
-       memset(mcl, 0, sizeof(Int_t)*kNTimeBins*kNSeedPlanes);
-       Int_t nused = 0;
-       for(Int_t ipl = 0; ipl < kNSeedPlanes; ipl++){
-               for(Int_t ils = 0; ils < nTimeBins; ils++){
-                       position = planes[ipl]*nTimeBins + ils;
-                       ncl[ipl * nTimeBins + ils] = layers[position].GetNClusters();
-                       nused = 0;
-                       for(Int_t icl = 0; icl < ncl[ipl * nTimeBins + ils]; icl++)
-                               if((layers[position].GetCluster(icl))->IsUsed()) nused++;
-                       ncl[ipl * nTimeBins + ils] -= nused;
-               }
-       }
-       // Declaration of quartils:
-       //Double_t qvals[3] = {0.0, 0.0, 0.0};
-       //Double_t qprop[3] = {0.16667, 0.5, 0.83333};
-       // Iterations
-       Int_t counter;
-       Double_t *array;
-       Int_t *limit;
-       Int_t nLayers = nTimeBins * kNSeedPlanes;
-       for(Int_t iter = 0; iter < 2; iter++){
-               array = (iter == 0) ? &ncl[0] : &mcl[0];
-               limit = (iter == 0) ? &nLayers : &counter;
-               counter = 0;
-               if(iter == 1){
-                       for(Int_t i = 0; i < nTimeBins *kNSeedPlanes; i++){
-                               if((ncl[i] >  mean + stdev) || (ncl[i] <  mean - stdev)) continue; // Outside 1-sigma region
-//                             if((ncl[i] >  qvals[2]) || (ncl[i] <  qvals[0])) continue; // Outside 1-sigma region
-                               if(ncl[i] == 0) continue;                                                // 0-Layers also rejected
-                               mcl[counter] = ncl[i];
-                               counter++;
-                       }
-               }
-               if(*limit == 0) break;
-               printf("Limit = %d\n", *limit);
-               //using quartils instead of mean and RMS 
-//             TMath::Quantiles(*limit,3,array,qvals,qprop,kFALSE);
-               mean = TMath::Median(*limit, array, 0x0);
-               stdev  = TMath::RMS(*limit, array);
-       }
-//     printf("Quantiles: 0.16667 = %3.3f, 0.5 = %3.3f, 0.83333 = %3.3f\n", qvals[0],qvals[1],qvals[2]);
-//     memcpy(params,qvals,sizeof(Double_t)*3);
-       params[1] = (Double_t)TMath::Nint(mean);
-       params[0] = (Double_t)TMath::Nint(mean - stdev);
-       params[2] = (Double_t)TMath::Nint(mean + stdev);
 
-}
+  // ratio of the total number of clusters/track which are expected to be found by the tracker.
+  const AliTRDrecoParam *fRecoPars = fReconstructor->GetRecoParam();
+  
+       Double_t chi2y = GetChi2Y(&cseed[0]);
+  Double_t chi2z = GetChi2Z(&cseed[0]);
+
+  Float_t nclusters = 0.;
+  Double_t sumda = 0.;
+  for(UChar_t ilayer = 0; ilayer < 4; ilayer++){
+    Int_t jlayer = planes[ilayer];
+    nclusters += cseed[jlayer].GetN2();
+    sumda += TMath::Abs(cseed[jlayer].GetYfitR(1) - cseed[jlayer].GetYref(1));
+  }
+  nclusters *= .25;
+
+  Double_t likea     = TMath::Exp(-sumda * fRecoPars->GetPhiCut());
+  Double_t likechi2y  = 0.0000000001;
+  if (fReconstructor->IsCosmic() || chi2y < 0.5) likechi2y += TMath::Exp(-TMath::Sqrt(chi2y) * fRecoPars->GetChi2YCut());
+  Double_t likechi2z = TMath::Exp(-chi2z * fRecoPars->GetChi2ZCut());
+  Double_t likeN     = TMath::Exp(-(fRecoPars->GetNMeanClusters() - nclusters) / fRecoPars->GetNSigmaClusters());
+  Double_t like      = likea * likechi2y * likechi2z * likeN;
+
+  //   AliInfo(Form("sumda(%f) chi2[0](%f) chi2[1](%f) likea(%f) likechi2y(%f) likechi2z(%f) nclusters(%d) likeN(%f)", sumda, chi2[0], chi2[1], likea, likechi2y, likechi2z, nclusters, likeN));
+  if(fReconstructor->GetStreamLevel(AliTRDReconstructor::kTracker) >= 2){
+    Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
+    Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
+    Int_t nTracklets = 0; Float_t mean_ncls = 0;
+    for(Int_t iseed=0; iseed < kNPlanes; iseed++){
+       if(!cseed[iseed].IsOK()) continue;
+       nTracklets++;
+       mean_ncls += cseed[iseed].GetN2();
+    }
+    if(nTracklets) mean_ncls /= nTracklets;
+    // The Debug Stream contains the seed 
+    TTreeSRedirector &cstreamer = *fgDebugStreamer;
+    cstreamer << "CookLikelihood"
+        << "EventNumber="                      << eventNumber
+        << "CandidateNumber=" << candidateNumber
+        << "tracklet0.="                       << &cseed[0]
+        << "tracklet1.="                       << &cseed[1]
+        << "tracklet2.="                       << &cseed[2]
+        << "tracklet3.="                       << &cseed[3]
+        << "tracklet4.="                       << &cseed[4]
+        << "tracklet5.="                       << &cseed[5]
+        << "sumda="                                            << sumda
+        << "chi2y="                                            << chi2y
+        << "chi2z="                                            << chi2z
+        << "likea="                                            << likea
+        << "likechi2y="                                << likechi2y
+        << "likechi2z="                                << likechi2z
+        << "nclusters="                                << nclusters
+        << "likeN="                                            << likeN
+        << "like="                                             << like
+        << "meanncls="        << mean_ncls
+        << "\n";
+  }
 
-//___________________________________________________________________
-Int_t AliTRDtrackerV1::GetSeedingLayers(AliTRDstackLayer *layers
-                                      , Double_t *params)
-{
-  //
-  // Algorithm to find optimal seeding layer
-  // Layers inside one sigma region (given by Quantiles) are sorted
-  // according to their difference.
-  // All layers outside are sorted according t
-  //
-  // Parameters:
-  //     - Array of AliTRDstackLayers (in the current plane !!!)
-  //     - Container for the Indices of the seeding Layer candidates
-  //
-  // Output:
-  //     - Number of Layers inside the 1-sigma-region
-  //
-  // The optimal seeding layer should contain the mean number of
-  // custers in the layers in one chamber.
-  //
-
-       //printf("Params: %3.3f, %3.3f, %3.3f\n", params[0], params[1], params[2]);
-       AliTRDcalibDB *cal = AliTRDcalibDB::Instance();
-       const Int_t kMaxClustersLayer = AliTRDstackLayer::kMaxClustersLayer;
-       Int_t nTimeBins = cal->GetNumberOfTimeBins();
-       Int_t ncl[kNTimeBins], indices[kNTimeBins], bins[kMaxClustersLayer];
-       memset(ncl, 0, sizeof(Int_t)*kNTimeBins);
-       memset(indices, 0, sizeof(Int_t)*kNTimeBins);
-       memset(bins, 0, sizeof(Int_t)*kMaxClustersLayer);
-       Int_t nused = 0;
-       for(Int_t ils = 0; ils < nTimeBins; ils++){
-               ncl[ils] = layers[ils].GetNClusters();
-               nused = 0;
-               for(Int_t icl = 0; icl < ncl[ils]; icl++)
-                       if((layers[ils].GetCluster(icl))->IsUsed()) nused++;
-               ncl[ils] -= nused;
-       }
-       
-       Float_t mean = params[1];
-       for(Int_t ils = 0; ils < nTimeBins; ils++){
-               memmove(indices + bins[ncl[ils]+1] + 1, indices + bins[ncl[ils]+1], sizeof(Int_t)*(nTimeBins - ils));
-               indices[bins[ncl[ils]+1]] = ils;
-               for(Int_t i = ncl[ils]+1; i < kMaxClustersLayer; i++)
-                       bins[i]++;
-       }
-       
-       //for(Int_t i = 0; i < nTimeBins; i++) printf("Bin %d = %d\n", i, bins[i]);
-       Int_t sbin = -1;
-       Int_t nElements;
-       Int_t position = 0;
-       TRandom *r = new TRandom();
-       Int_t iter = 0;
-       while(1){
-               while(sbin < (Int_t)params[0] || sbin > (Int_t)params[2]){
-                       // Randomly selecting one bin
-                       sbin = (Int_t)r->Poisson(mean);
-               }
-               printf("Bin = %d\n",sbin);
-               //Randomly selecting one Layer in the bin
-               nElements = bins[sbin + 1] - bins[sbin];
-               printf("nElements = %d\n", nElements);
-               if(iter == 5){
-                       position = (Int_t)(gRandom->Rndm()*(nTimeBins-1));
-                       break;
-               }
-               else if(nElements==0){
-                       iter++;
-                       continue;
-               }
-               position = (Int_t)(gRandom->Rndm()*(nElements-1)) + bins[sbin];
-               break;
-       }
-       delete r;
-       return indices[position];
+  return like;
 }
 
-//____________________________________________________________________
-AliTRDcluster *AliTRDtrackerV1::FindSeedingCluster(AliTRDstackLayer *layers
-                                                 , AliTRDseedV1/*AliRieman*/ *reference)
-{
-  //
-  // Finds a seeding Cluster for the extrapolation chamber.
-  //
-  // The seeding cluster should be as close as possible to the assumed
-  // track which is represented by a Rieman fit.
-  // Therefore the selecting criterion is the minimum distance between
-  // the best fitting cluster and the Reference which is derived from
-  // the AliTRDseed. Because all layers are assumed to be equally good
-  // a linear search is performed.
-  //
-  // Imput parameters: - layers: array of AliTRDstackLayers (in one chamber!!!)
-  //                   - sfit: the reference
-  //
-  // Output:           - the best seeding cluster
-  //
-
-       AliTRDcalibDB *cal = AliTRDcalibDB::Instance();
-       Int_t nTimeBins = cal->GetNumberOfTimeBins();
-       
-       // distances as squared distances
-       Int_t index = 0;
-       Float_t ypos = 0.0, zpos = 0.0, distance = 0.0, nearestDistance =100000.0; 
-       ypos = reference->GetYref(0);
-       zpos = reference->GetZref(0);
-       AliTRDcluster *currentBest = 0x0, *temp = 0x0;
-       for(Int_t ils = 0; ils < nTimeBins; ils++){
-               // Reference positions
-//             ypos = reference->GetYat(layers[ils].GetX());
-//             zpos = reference->GetZat(layers[ils].GetX());
-               index = layers[ils].SearchNearestCluster(ypos, zpos, fRecoParam->GetRoad2y(), fRecoParam->GetRoad2z());
-               if(index == -1) continue;
-               temp = layers[ils].GetCluster(index);
-               if(!temp) continue;
-               distance = (temp->GetY() - ypos) * (temp->GetY() - ypos) + (temp->GetZ() - zpos) * (temp->GetZ() - zpos);
-               if(distance < nearestDistance){
-                       nearestDistance = distance;
-                       currentBest = temp;
-               }
-       }
-       return currentBest;
-}
 
-//____________________________________________________________________
-AliTRDstackLayer *AliTRDtrackerV1::MakeSeedingLayer(AliTRDstackLayer *layers
-                                                  , Int_t plane)
-{
-  //
-  // Creates a seeding layer
-  //
-       
-       // constants
-       const Int_t kMaxRows = 16;
-       const Int_t kMaxCols = 144;
-       const Int_t kMaxPads = 2304;
-       
-       // Get the calculation
-       AliTRDcalibDB *cal = AliTRDcalibDB::Instance();
-       Int_t nTimeBins = cal->GetNumberOfTimeBins();
-       
-       // Get the geometrical data of the chamber
-       AliTRDpadPlane *pp = fGeom->GetPadPlane(plane, layers[0].GetStackNr());
-       Int_t nCols = pp->GetNcols();
-       Float_t ymin = TMath::Min(pp->GetCol0(), pp->GetColEnd());
-       Float_t ymax = TMath::Max(pp->GetCol0(), pp->GetColEnd());
-       Float_t zmin = TMath::Min(pp->GetRow0(), pp->GetRowEnd());
-       Float_t zmax = TMath::Max(pp->GetRow0(), pp->GetRowEnd());
-       Int_t nRows = pp->GetNrows();
-       Float_t binlength = (ymax - ymin)/nCols; 
-       //AliInfo(Form("ymin(%f) ymax(%f) zmin(%f) zmax(%f) nRows(%d) binlength(%f)", ymin, ymax, zmin, zmax, nRows, binlength));
-       
-       // Fill the histogram
-       Int_t arrpos;
-       Float_t ypos;
-       Int_t irow, nClusters;  
-       Int_t *histogram[kMaxRows];                                                                                     // 2D-Histogram
-       Int_t hvals[kMaxPads];  memset(hvals, 0, sizeof(Int_t)*kMaxPads);       
-       Float_t *sigmas[kMaxRows];
-       Float_t svals[kMaxPads];        memset(svals, 0, sizeof(Float_t)*kMaxPads);     
-       AliTRDcluster *c = 0x0;
-       for(Int_t irs = 0; irs < kMaxRows; irs++){
-               histogram[irs] = &hvals[irs*kMaxCols];
-               sigmas[irs] = &svals[irs*kMaxCols];
-       }
-       for(Int_t iTime = 0; iTime < nTimeBins; iTime++){
-               nClusters = layers[iTime].GetNClusters();
-               for(Int_t incl = 0; incl < nClusters; incl++){
-                       c = layers[iTime].GetCluster(incl);     
-                       ypos = c->GetY();
-                       if(ypos > ymax && ypos < ymin) continue;
-                       irow = pp->GetPadRowNumber(c->GetZ());                          // Zbin
-                       if(irow < 0)continue;
-                       arrpos = static_cast<Int_t>((ypos - ymin)/binlength);
-                       if(ypos == ymax) arrpos = nCols - 1;
-                       histogram[irow][arrpos]++;
-                       sigmas[irow][arrpos] += c->GetSigmaZ2();
-               }
-       }
-       
-// Now I have everything in the histogram, do the selection
-//     printf("Starting the analysis\n");
-       //Int_t nPads = nCols * nRows;
-       // This is what we are interested in: The center of gravity of the best candidates
-       Float_t cogyvals[kMaxPads]; memset(cogyvals, 0, sizeof(Float_t)*kMaxPads);
-       Float_t cogzvals[kMaxPads]; memset(cogzvals, 0, sizeof(Float_t)*kMaxPads);
-       Float_t *cogy[kMaxRows];
-       Float_t *cogz[kMaxRows];
-       // Lookup-Table storing coordinates according ti the bins
-       Float_t yLengths[kMaxCols];
-       Float_t zLengths[kMaxRows];
-       for(Int_t icnt = 0; icnt < nCols; icnt++){
-               yLengths[icnt] = pp->GetColPos(nCols - 1 - icnt) + binlength/2;
-       }
-       for(Int_t icnt = 0; icnt < nRows; icnt++){
-               zLengths[icnt] = pp->GetRowPos(icnt) - pp->GetRowSize(icnt)/2;
-       }
-
-       // A bitfield is used to mask the pads as usable
-       Short_t mask[kMaxCols]; memset(mask, 0 ,sizeof(Short_t) * kMaxCols);//bool mvals[kMaxPads];
-       for(UChar_t icount = 0; icount < nRows; icount++){
-               cogy[icount] = &cogyvals[icount*kMaxCols];
-               cogz[icount] = &cogzvals[icount*kMaxCols];
-       }
-       // In this array the array position of the best candidates will be stored
-       Int_t cand[kMaxTracksStack];
-       Float_t sigcands[kMaxTracksStack];
-       
-       // helper variables
-       Int_t indices[kMaxPads]; memset(indices, 0, sizeof(Int_t)*kMaxPads);
-       Int_t nCandidates = 0;
-       Float_t norm, cogv;
-       // histogram filled -> Select best bins
-       TMath::Sort(kMaxPads, hvals, indices);                  // bins storing a 0 should not matter
-       // Set Threshold
-       Int_t maximum = hvals[indices[0]];      // best
-       Int_t threshold = static_cast<UChar_t>(maximum * fRecoParam->GetFindableClusters());
-       Int_t col, row, lower, lower1, upper, upper1;
-       for(Int_t ib = 0; ib < kMaxPads; ib++){
-               if(nCandidates >= kMaxTracksStack){
-                       AliWarning(Form("Number of seed candidates %d exceeded maximum allowed per stack %d", nCandidates, kMaxTracksStack));
-                       break;
-               }
-               // Positions
-               row = indices[ib]/nCols;
-               col = indices[ib]%nCols;
-               // here will be the threshold condition:
-               if((mask[col] & (1 << row)) != 0) continue;             // Pad is masked: continue
-               if(histogram[row][col] < TMath::Max(threshold, 1)){     // of course at least one cluster is needed
-                       break;                  // number of clusters below threshold: break;
-               } 
-               // passing: Mark the neighbors
-               lower  = TMath::Max(col - 1, 0); upper  = TMath::Min(col + 2, nCols);
-               lower1 = TMath::Max(row - 1, 0); upper1 = TMath::Min(row + 2, nCols);
-               for(Int_t ic = lower; ic < upper; ++ic)
-                       for(Int_t ir = lower1; ir < upper1; ++ir){
-                               if(ic == col && ir == row) continue;
-                               mask[ic] |= (1 << ir);
-                       }
-               // Storing the position in an array
-               // testing for neigboring
-               cogv = 0;
-               norm = 0;
-               lower = TMath::Max(col - 1,0);
-               upper = TMath::Min(col + 2, nCols);
-               for(Int_t inb = lower; inb < upper; ++inb){
-                       cogv += yLengths[inb] * histogram[row][inb];
-                       norm += histogram[row][inb];
-               }
-               cogy[row][col] = cogv / norm;
-               cogv = 0; norm = 0;
-               lower = TMath::Max(row - 1, 0);
-               upper = TMath::Min(row + 2, nRows);
-               for(Int_t inb = lower; inb < upper; ++inb){
-                       cogv += zLengths[inb] * histogram[inb][col];
-                       norm += histogram[inb][col];
-               }
-               cogz[row][col] = cogv /  norm;
-               // passed the filter
-               cand[nCandidates] = row*kMaxCols + col; // store the position of a passig candidate into an Array
-               sigcands[nCandidates] = sigmas[row][col] / histogram[row][col]; // never be a floating point exeption
-               // Analysis output
-               nCandidates++;
-       }
-       AliTRDstackLayer *fakeLayer = new AliTRDstackLayer(layers[0].GetZ0(), layers[0].GetDZ0(), layers[0].GetStackNr());
-       fakeLayer->SetX((TMath::Abs(layers[nTimeBins-1].GetX() + layers[0].GetX()))/2);
-       fakeLayer->SetSector(layers[0].GetSector());
-       AliTRDcluster **fakeClusters = 0x0;
-       UInt_t *fakeIndices = 0x0;
-       if(nCandidates){
-               fakeClusters = new AliTRDcluster*[nCandidates];
-               fakeIndices = new UInt_t[nCandidates];
-               UInt_t fakeIndex = 0;
-               for(Int_t ican = 0; ican < nCandidates; ican++){
-                       fakeClusters[ican] = new AliTRDcluster();
-                       fakeClusters[ican]->SetX(fakeLayer->GetX());
-                       fakeClusters[ican]->SetY(cogyvals[cand[ican]]);
-                       fakeClusters[ican]->SetZ(cogzvals[cand[ican]]);
-                       fakeClusters[ican]->SetSigmaZ2(sigcands[ican]);
-                       fakeIndices[ican] = fakeIndex++;// fantasy number
-               }
-       }
-       fakeLayer->SetRecoParam(fRecoParam);
-       fakeLayer->SetClustersArray(fakeClusters, nCandidates);
-       fakeLayer->SetIndexArray(fakeIndices);
-       fakeLayer->SetNRows(nRows);
-       fakeLayer->BuildIndices();
-       //fakeLayer->PrintClusters();
-       
-#ifdef DEBUG
-       if(AliTRDReconstructor::StreamLevel() >= 3){
-               TMatrixD hist(nRows, nCols);
-               for(Int_t i = 0; i < nRows; i++)
-                       for(Int_t j = 0; j < nCols; j++)
-                               hist(i,j) = histogram[i][j];
-               TTreeSRedirector &cstreamer = *fDebugStreamer;
-               cstreamer << "MakeSeedingLayer"
-                       << "Iteration="  << fSieveSeeding
-                       << "plane="      << plane
-                       << "ymin="       << ymin
-                       << "ymax="       << ymax
-                       << "zmin="       << zmin
-                       << "zmax="       << zmax
-                       << "L.="         << fakeLayer
-                       << "Histogram.=" << &hist
-                       << "\n";
-       }
-#endif
-       return fakeLayer;
-}
 
 //____________________________________________________________________
 void AliTRDtrackerV1::GetSeedingConfig(Int_t iconfig, Int_t planes[4])
@@ -2472,98 +2934,98 @@ void AliTRDtrackerV1::GetSeedingConfig(Int_t iconfig, Int_t planes[4])
   //End_Html
   //
 
-       switch(iconfig){
-       case 0: // 5432 TQ 0
-               planes[0] = 2;
-               planes[1] = 3;
-               planes[2] = 4;
-               planes[3] = 5;
-               break;
-       case 1: // 4321 TQ 0
-               planes[0] = 1;
-               planes[1] = 2;
-               planes[2] = 3;
-               planes[3] = 4;
-               break;
-       case 2: // 3210 TQ 0
-               planes[0] = 0;
-               planes[1] = 1;
-               planes[2] = 2;
-               planes[3] = 3;
-               break;
-       case 3: // 5321 TQ 1
-               planes[0] = 1;
-               planes[1] = 2;
-               planes[2] = 3;
-               planes[3] = 5;
-               break;
-       case 4: // 4210 TQ 1
-               planes[0] = 0;
-               planes[1] = 1;
-               planes[2] = 2;
-               planes[3] = 4;
-               break;
-       case 5: // 5431 TQ 1
-               planes[0] = 1;
-               planes[1] = 3;
-               planes[2] = 4;
-               planes[3] = 5;
-               break;
-       case 6: // 4320 TQ 1
-               planes[0] = 0;
-               planes[1] = 2;
-               planes[2] = 3;
-               planes[3] = 4;
-               break;
-       case 7: // 5430 TQ 2
-               planes[0] = 0;
-               planes[1] = 3;
-               planes[2] = 4;
-               planes[3] = 5;
-               break;
-       case 8: // 5210 TQ 2
-               planes[0] = 0;
-               planes[1] = 1;
-               planes[2] = 2;
-               planes[3] = 5;
-               break;
-       case 9: // 5421 TQ 3
-               planes[0] = 1;
-               planes[1] = 2;
-               planes[2] = 4;
-               planes[3] = 5;
-               break;
-       case 10: // 4310 TQ 3
-               planes[0] = 0;
-               planes[1] = 1;
-               planes[2] = 3;
-               planes[3] = 4;
-               break;
-       case 11: // 5410 TQ 4
-               planes[0] = 0;
-               planes[1] = 1;
-               planes[2] = 4;
-               planes[3] = 5;
-               break;
-       case 12: // 5420 TQ 5
-               planes[0] = 0;
-               planes[1] = 2;
-               planes[2] = 4;
-               planes[3] = 5;
-               break;
-       case 13: // 5320 TQ 5
-               planes[0] = 0;
-               planes[1] = 2;
-               planes[2] = 3;
-               planes[3] = 5;
-               break;
-       case 14: // 5310 TQ 5
-               planes[0] = 0;
-               planes[1] = 1;
-               planes[2] = 3;
-               planes[3] = 5;
-               break;
-       }
+  switch(iconfig){
+  case 0: // 5432 TQ 0
+    planes[0] = 2;
+    planes[1] = 3;
+    planes[2] = 4;
+    planes[3] = 5;
+    break;
+  case 1: // 4321 TQ 0
+    planes[0] = 1;
+    planes[1] = 2;
+    planes[2] = 3;
+    planes[3] = 4;
+    break;
+  case 2: // 3210 TQ 0
+    planes[0] = 0;
+    planes[1] = 1;
+    planes[2] = 2;
+    planes[3] = 3;
+    break;
+  case 3: // 5321 TQ 1
+    planes[0] = 1;
+    planes[1] = 2;
+    planes[2] = 3;
+    planes[3] = 5;
+    break;
+  case 4: // 4210 TQ 1
+    planes[0] = 0;
+    planes[1] = 1;
+    planes[2] = 2;
+    planes[3] = 4;
+    break;
+  case 5: // 5431 TQ 1
+    planes[0] = 1;
+    planes[1] = 3;
+    planes[2] = 4;
+    planes[3] = 5;
+    break;
+  case 6: // 4320 TQ 1
+    planes[0] = 0;
+    planes[1] = 2;
+    planes[2] = 3;
+    planes[3] = 4;
+    break;
+  case 7: // 5430 TQ 2
+    planes[0] = 0;
+    planes[1] = 3;
+    planes[2] = 4;
+    planes[3] = 5;
+    break;
+  case 8: // 5210 TQ 2
+    planes[0] = 0;
+    planes[1] = 1;
+    planes[2] = 2;
+    planes[3] = 5;
+    break;
+  case 9: // 5421 TQ 3
+    planes[0] = 1;
+    planes[1] = 2;
+    planes[2] = 4;
+    planes[3] = 5;
+    break;
+  case 10: // 4310 TQ 3
+    planes[0] = 0;
+    planes[1] = 1;
+    planes[2] = 3;
+    planes[3] = 4;
+    break;
+  case 11: // 5410 TQ 4
+    planes[0] = 0;
+    planes[1] = 1;
+    planes[2] = 4;
+    planes[3] = 5;
+    break;
+  case 12: // 5420 TQ 5
+    planes[0] = 0;
+    planes[1] = 2;
+    planes[2] = 4;
+    planes[3] = 5;
+    break;
+  case 13: // 5320 TQ 5
+    planes[0] = 0;
+    planes[1] = 2;
+    planes[2] = 3;
+    planes[3] = 5;
+    break;
+  case 14: // 5310 TQ 5
+    planes[0] = 0;
+    planes[1] = 1;
+    planes[2] = 3;
+    planes[3] = 5;
+    break;
+  }
 }
 
 //____________________________________________________________________
@@ -2582,66 +3044,344 @@ void AliTRDtrackerV1::GetExtrapolationConfig(Int_t iconfig, Int_t planes[2])
   // Detailed description
   //
 
-       switch(iconfig){
-       case 0: // 5432 TQ 0
-               planes[0] = 1;
-               planes[1] = 0;
-               break;
-       case 1: // 4321 TQ 0
-               planes[0] = 5;
-               planes[1] = 0;
-               break;
-       case 2: // 3210 TQ 0
-               planes[0] = 4;
-               planes[1] = 5;
-               break;
-       case 3: // 5321 TQ 1
-               planes[0] = 4;
-               planes[1] = 0;
-               break;
-       case 4: // 4210 TQ 1
-               planes[0] = 5;
-               planes[1] = 3;
-               break;
-       case 5: // 5431 TQ 1
-               planes[0] = 2;
-               planes[1] = 0;
-               break;
-       case 6: // 4320 TQ 1
-               planes[0] = 5;
-               planes[1] = 1;
-               break;
-       case 7: // 5430 TQ 2
-               planes[0] = 2;
-               planes[1] = 1;
-               break;
-       case 8: // 5210 TQ 2
-               planes[0] = 4;
-               planes[1] = 3;
-               break;
-       case 9: // 5421 TQ 3
-               planes[0] = 3;
-               planes[1] = 0;
-               break;
-       case 10: // 4310 TQ 3
-               planes[0] = 5;
-               planes[1] = 2;
-               break;
-       case 11: // 5410 TQ 4
-               planes[0] = 3;
-               planes[1] = 2;
-               break;
-       case 12: // 5420 TQ 5
-               planes[0] = 3;
-               planes[1] = 1;
-               break;
-       case 13: // 5320 TQ 5
-               planes[0] = 4;
-               planes[1] = 1;
-               break;
-       case 14: // 5310 TQ 5
-               planes[0] = 4;
-               planes[1] = 2;
-               break;
-       }
+  switch(iconfig){
+  case 0: // 5432 TQ 0
+    planes[0] = 1;
+    planes[1] = 0;
+    break;
+  case 1: // 4321 TQ 0
+    planes[0] = 5;
+    planes[1] = 0;
+    break;
+  case 2: // 3210 TQ 0
+    planes[0] = 4;
+    planes[1] = 5;
+    break;
+  case 3: // 5321 TQ 1
+    planes[0] = 4;
+    planes[1] = 0;
+    break;
+  case 4: // 4210 TQ 1
+    planes[0] = 5;
+    planes[1] = 3;
+    break;
+  case 5: // 5431 TQ 1
+    planes[0] = 2;
+    planes[1] = 0;
+    break;
+  case 6: // 4320 TQ 1
+    planes[0] = 5;
+    planes[1] = 1;
+    break;
+  case 7: // 5430 TQ 2
+    planes[0] = 2;
+    planes[1] = 1;
+    break;
+  case 8: // 5210 TQ 2
+    planes[0] = 4;
+    planes[1] = 3;
+    break;
+  case 9: // 5421 TQ 3
+    planes[0] = 3;
+    planes[1] = 0;
+    break;
+  case 10: // 4310 TQ 3
+    planes[0] = 5;
+    planes[1] = 2;
+    break;
+  case 11: // 5410 TQ 4
+    planes[0] = 3;
+    planes[1] = 2;
+    break;
+  case 12: // 5420 TQ 5
+    planes[0] = 3;
+    planes[1] = 1;
+    break;
+  case 13: // 5320 TQ 5
+    planes[0] = 4;
+    planes[1] = 1;
+    break;
+  case 14: // 5310 TQ 5
+    planes[0] = 4;
+    planes[1] = 2;
+    break;
+  }
+}
+
+//____________________________________________________________________
+AliCluster* AliTRDtrackerV1::GetCluster(Int_t idx) const
+{
+  Int_t ncls = fClusters->GetEntriesFast();
+  return idx >= 0 && idx < ncls ? (AliCluster*)fClusters->UncheckedAt(idx) : 0x0;
+}
+
+//____________________________________________________________________
+AliTRDseedV1* AliTRDtrackerV1::GetTracklet(Int_t idx) const
+{
+  Int_t ntrklt = fTracklets->GetEntriesFast();
+  return idx >= 0 && idx < ntrklt ? (AliTRDseedV1*)fTracklets->UncheckedAt(idx) : 0x0;
+}
+
+//____________________________________________________________________
+AliKalmanTrack* AliTRDtrackerV1::GetTrack(Int_t idx) const
+{
+  Int_t ntrk = fTracks->GetEntriesFast();
+  return idx >= 0 && idx < ntrk ? (AliKalmanTrack*)fTracks->UncheckedAt(idx) : 0x0;
+}
+
+//____________________________________________________________________
+Float_t AliTRDtrackerV1::CalculateReferenceX(AliTRDseedV1 *tracklets){
+  //
+  // Calculates the reference x-position for the tilted Rieman fit defined as middle
+  // of the stack (middle between layers 2 and 3). For the calculation all the tracklets
+  // are taken into account
+  // 
+  // Parameters:       - Array of tracklets(AliTRDseedV1)
+  //
+  // Output:           - The reference x-position(Float_t)
+  //
+  Int_t nDistances = 0;
+  Float_t meanDistance = 0.;
+  Int_t startIndex = 5;
+  for(Int_t il =5; il > 0; il--){
+    if(tracklets[il].IsOK() && tracklets[il -1].IsOK()){
+      Float_t xdiff = tracklets[il].GetX0() - tracklets[il -1].GetX0();
+      meanDistance += xdiff;
+      nDistances++;
+    }
+    if(tracklets[il].IsOK()) startIndex = il;
+  }
+  if(tracklets[0].IsOK()) startIndex = 0;
+  if(!nDistances){
+    // We should normally never get here
+    Float_t xpos[2]; memset(xpos, 0, sizeof(Float_t) * 2);
+    Int_t iok = 0, idiff = 0;
+    // This attempt is worse and should be avoided:
+    // check for two chambers which are OK and repeat this without taking the mean value
+    // Strategy avoids a division by 0;
+    for(Int_t il = 5; il >= 0; il--){
+      if(tracklets[il].IsOK()){
+  xpos[iok] = tracklets[il].GetX0();
+  iok++;
+  startIndex = il;
+      }
+      if(iok) idiff++; // to get the right difference;
+      if(iok > 1) break;
+    }
+    if(iok > 1){
+      meanDistance = (xpos[0] - xpos[1])/idiff;
+    }
+    else{
+      // we have do not even have 2 layers which are OK? The we do not need to fit at all
+      return 331.;
+    }
+  }
+  else{
+    meanDistance /= nDistances;
+  }
+  return tracklets[startIndex].GetX0() + (2.5 - startIndex) * meanDistance - 0.5 * (AliTRDgeometry::AmThick() + AliTRDgeometry::DrThick());
+}
+
+//_____________________________________________________________________________
+Int_t AliTRDtrackerV1::Freq(Int_t n, const Int_t *inlist
+          , Int_t *outlist, Bool_t down)
+{    
+  //
+  // Sort eleements according occurancy 
+  // The size of output array has is 2*n 
+  //
+
+  if (n <= 0) {
+    return 0;
+  }
+
+  Int_t *sindexS = new Int_t[n];   // Temporary array for sorting
+  Int_t *sindexF = new Int_t[2*n];   
+  for (Int_t i = 0; i < n; i++) {
+    sindexF[i] = 0;
+  }
+
+  TMath::Sort(n,inlist,sindexS,down); 
+
+  Int_t last     = inlist[sindexS[0]];
+  Int_t val      = last;
+  sindexF[0]     = 1;
+  sindexF[0+n]   = last;
+  Int_t countPos = 0;
+
+  // Find frequency
+  for (Int_t i = 1; i < n; i++) {
+    val = inlist[sindexS[i]];
+    if (last == val) {
+      sindexF[countPos]++;
+    }
+    else {      
+      countPos++;
+      sindexF[countPos+n] = val;
+      sindexF[countPos]++;
+      last                = val;
+    }
+  }
+  if (last == val) {
+    countPos++;
+  }
+
+  // Sort according frequency
+  TMath::Sort(countPos,sindexF,sindexS,kTRUE);
+
+  for (Int_t i = 0; i < countPos; i++) {
+    outlist[2*i  ] = sindexF[sindexS[i]+n];
+    outlist[2*i+1] = sindexF[sindexS[i]];
+  }
+
+  delete [] sindexS;
+  delete [] sindexF;
+  
+  return countPos;
+
+}
+
+
+//____________________________________________________________________
+void AliTRDtrackerV1::SetReconstructor(const AliTRDReconstructor *rec)
+{
+  fReconstructor = rec;
+  if(fReconstructor->GetStreamLevel(AliTRDReconstructor::kTracker) > 1){
+    if(!fgDebugStreamer){
+      TDirectory *savedir = gDirectory;
+      fgDebugStreamer = new TTreeSRedirector("TRD.TrackerDebug.root");
+      savedir->cd();
+    }
+  }    
+}
+
+//_____________________________________________________________________________
+Float_t AliTRDtrackerV1::GetChi2Y(AliTRDseedV1 *tracklets) const
+{
+  //   Chi2 definition on y-direction
+
+  Float_t chi2 = 0;
+  for(Int_t ipl = 0; ipl < kNPlanes; ipl++){
+    if(!tracklets[ipl].IsOK()) continue;
+    Double_t distLayer = (tracklets[ipl].GetYfit(0) - tracklets[ipl].GetYref(0));// /tracklets[ipl].GetSigmaY(); 
+    chi2 += distLayer * distLayer;
+  }
+  return chi2;
+}
+
+//____________________________________________________________________
+void AliTRDtrackerV1::ResetSeedTB()
+{
+// reset buffer for seeding time bin layers. If the time bin 
+// layers are not allocated this function allocates them  
+
+  for(Int_t isl=0; isl<kNSeedPlanes; isl++){
+    if(!fSeedTB[isl]) fSeedTB[isl] = new AliTRDchamberTimeBin();
+    else fSeedTB[isl]->Clear();
+  }
+}
+
+//_____________________________________________________________________________
+Float_t AliTRDtrackerV1::GetChi2Z(AliTRDseedV1 *tracklets) const 
+{
+  //   Calculates normalized chi2 in z-direction
+
+  Float_t chi2 = 0;
+  // chi2 = Sum ((z - zmu)/sigma)^2
+  // Sigma for the z direction is defined as half of the padlength
+  for(Int_t ipl = 0; ipl < kNPlanes; ipl++){
+    if(!tracklets[ipl].IsOK()) continue;
+    Double_t distLayer = (tracklets[ipl].GetMeanz() - tracklets[ipl].GetZref(0)); // /(tracklets[ipl].GetPadLength()/2); 
+    chi2 += distLayer * distLayer;
+  }
+  return chi2;
+}
+
+///////////////////////////////////////////////////////
+//                                                   //
+// Resources of class AliTRDLeastSquare              //
+//                                                   //
+///////////////////////////////////////////////////////
+
+//_____________________________________________________________________________
+AliTRDtrackerV1::AliTRDLeastSquare::AliTRDLeastSquare(){
+  //
+  // Constructor of the nested class AliTRDtrackFitterLeastSquare
+  //
+  memset(fParams, 0, sizeof(Double_t) * 2);
+  memset(fSums, 0, sizeof(Double_t) * 5);
+  memset(fCovarianceMatrix, 0, sizeof(Double_t) * 3);
+
+}
+
+//_____________________________________________________________________________
+void AliTRDtrackerV1::AliTRDLeastSquare::AddPoint(Double_t *x, Double_t y, Double_t sigmaY){
+  //
+  // Adding Point to the fitter
+  //
+  Double_t weight = 1/(sigmaY * sigmaY);
+  Double_t &xpt = *x;
+  //   printf("Adding point x = %f, y = %f, sigma = %f\n", xpt, y, sigmaY);
+  fSums[0] += weight;
+  fSums[1] += weight * xpt;
+  fSums[2] += weight * y;
+  fSums[3] += weight * xpt * y;
+  fSums[4] += weight * xpt * xpt;
+  fSums[5] += weight * y * y;
+}
+
+//_____________________________________________________________________________
+void AliTRDtrackerV1::AliTRDLeastSquare::RemovePoint(Double_t *x, Double_t y, Double_t sigmaY){
+  //
+  // Remove Point from the sample
+  //
+  Double_t weight = 1/(sigmaY * sigmaY);
+  Double_t &xpt = *x; 
+  fSums[0] -= weight;
+  fSums[1] -= weight * xpt;
+  fSums[2] -= weight * y;
+  fSums[3] -= weight * xpt * y;
+  fSums[4] -= weight * xpt * xpt;
+  fSums[5] -= weight * y * y;
+}
+
+//_____________________________________________________________________________
+void AliTRDtrackerV1::AliTRDLeastSquare::Eval(){
+  //
+  // Evaluation of the fit:
+  // Calculation of the parameters
+  // Calculation of the covariance matrix
+  //
+  
+  Double_t denominator = fSums[0] * fSums[4] - fSums[1] *fSums[1];
+  if(denominator==0) return;
+
+  //   for(Int_t isum = 0; isum < 5; isum++)
+  //           printf("fSums[%d] = %f\n", isum, fSums[isum]);
+  //   printf("denominator = %f\n", denominator);
+  fParams[0] = (fSums[2] * fSums[4] - fSums[1] * fSums[3])/ denominator;
+  fParams[1] = (fSums[0] * fSums[3] - fSums[1] * fSums[2]) / denominator;
+  //   printf("fParams[0] = %f, fParams[1] = %f\n", fParams[0], fParams[1]);
+  
+  // Covariance matrix
+  fCovarianceMatrix[0] = fSums[4] - fSums[1] * fSums[1] / fSums[0];
+  fCovarianceMatrix[1] = fSums[5] - fSums[2] * fSums[2] / fSums[0];
+  fCovarianceMatrix[2] = fSums[3] - fSums[1] * fSums[2] / fSums[0];
+}
+
+//_____________________________________________________________________________
+Double_t AliTRDtrackerV1::AliTRDLeastSquare::GetFunctionValue(Double_t *xpos) const {
+  //
+  // Returns the Function value of the fitted function at a given x-position
+  //
+  return fParams[0] + fParams[1] * (*xpos);
+}
+
+//_____________________________________________________________________________
+void AliTRDtrackerV1::AliTRDLeastSquare::GetCovarianceMatrix(Double_t *storage) const {
+  //
+  // Copies the values of the covariance matrix into the storage
+  //
+  memcpy(storage, fCovarianceMatrix, sizeof(Double_t) * 3);
 }
+