[u/mrichter/AliRoot.git] / ITS / UPGRADE / AliITSUTrackerGlo.cxx

/**************************************************************************
 * 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.                  *
 **************************************************************************/

/*
  TO CHECK
  GetBz usage

 */

//-------------------------------------------------------------------------
//  Implementation of the ITS Upgrade tracker mother class.              
//-------------------------------------------------------------------------
#include <TTree.h>
#include <Riostream.h> 
#include <TMath.h>
#include <TFile.h>

#include "AliITSUTrackerGlo.h"
#include "AliESDEvent.h"
#include "AliESDtrack.h"
#include "AliITSURecoDet.h"
#include "AliITSURecoSens.h"
#include "AliITSUReconstructor.h"
#include "AliITSReconstructor.h"
#include "AliITSUSeed.h"
#include "AliITSUAux.h"
#include "AliITSUClusterPix.h"
#include "AliITSUGeomTGeo.h"
#include "AliCodeTimer.h"
#include "AliRefArray.h"
using namespace AliITSUAux;
using namespace TMath;

//----------------- tmp stuff -----------------

ClassImp(AliITSUTrackerGlo)

const Double_t AliITSUTrackerGlo::fgkToler =  1e-6;// tolerance for layer on-surface check


//_________________________________________________________________________
AliITSUTrackerGlo::AliITSUTrackerGlo(AliITSUReconstructor* rec)
:  fReconstructor(rec)
  ,fITS(0)
  ,fCurrESDtrack(0)
  ,fCurrESDtrMClb(kDummyLabel)
  ,fCurrMass(kPionMass)
  ,fCountProlongationTrials(0)
  ,fCountITSin(0)
  ,fCountITSout(0)
  ,fCountITSrefit(0)
  ,fHypStore(100)
  ,fLayerMaxCandidates(1000)
  ,fLayerCandidates(0)
  ,fNBranchesAdded(0)
  ,fNCandidatesAdded(0)
  ,fCurrHyp(0)
  ,fWorkHyp(0)
  ,fSeedsPool("AliITSUSeed",0)
  ,fFreeSeedsID(0)
  ,fESDIndex(0)
  ,fNFreeSeeds(0)
  ,fLastSeedID(0)
  ,fNLrActive(0)
  ,fDefTrackConds(0)
  ,fCurrTrackCond(0)
  ,fCurrActLrID(-1)
  ,fCurrLayer(0)
  ,fTrackPhase(-1)
#ifdef  _FILL_CONTROL_HISTOS_
  ,fCHistoArr(0)
#endif
{
  // Default constructor
  if (rec) Init(rec);
}

//_________________________________________________________________________
AliITSUTrackerGlo::~AliITSUTrackerGlo()
{
 // Default destructor
 //  
  delete[] fLayerCandidates;
  if (fWorkHyp) fWorkHyp->SetTPCSeed(0); // this hypothesis does not own the seed
  delete fWorkHyp;
  //
#ifdef  _FILL_CONTROL_HISTOS_
  if (fCHistoArr) {
    TFile* ctrOut = TFile::Open("itsuControlHistos.root","recreate");
    ctrOut->cd();
    AliInfo("Storing control histos");
    fCHistoArr->Print();
    //    ctrOut->WriteObject(fCHistoArr,"controlH","kSingleKey");
    fCHistoArr->Write();
    ctrOut->Close();
    delete ctrOut;
    fCHistoArr = 0;
  }
#endif 
  //
}

//_________________________________________________________________________
void AliITSUTrackerGlo::Init(AliITSUReconstructor* rec)
{
  // init with external reconstructor
  //
  fITS = rec->GetITSInterface();
  fNLrActive = fITS->GetNLayersActive();
  fWorkHyp = new AliITSUTrackHyp(fNLrActive);
  //
  if (fLayerMaxCandidates<1) fLayerMaxCandidates = 1000;
  fLayerCandidates = new AliITSUSeed*[fLayerMaxCandidates];
  fSeedsPool.ExpandCreateFast(1000); // RS TOCHECK
  fFreeSeedsID.Set(1000);
  fESDIndex.Set(1000);
  
  //
}

//_________________________________________________________________________
void AliITSUTrackerGlo::CreateDefaultTrackCond()
{
  // creates default tracking conditions to be used when recoparam does not provide them

  AliITSUTrackCond* cond = new AliITSUTrackCond();
  //
  cond->SetNLayers(fNLrActive);
  cond->AddNewCondition(fNLrActive);
  cond->AddGroupPattern( 0xffff ); // require all layers hit
  cond->Init();
  //
  fDefTrackConds.AddLast(cond);
  //
  AliInfo("Created conditions: ");
  for (int i=0;i<fDefTrackConds.GetEntriesFast();i++) fDefTrackConds[i]->Print();
  //
}


//_________________________________________________________________________
Int_t AliITSUTrackerGlo::Clusters2Tracks(AliESDEvent *esdEv)
{
  //
  AliCodeTimerAuto("",0);
  SetTrackingPhase(kClus2Tracks);
  //
#ifdef  _FILL_CONTROL_HISTOS_
  if (!fCHistoArr) BookControlHistos();
#endif
  static int evID = 0;
  static TArrayF esdTrPt(fESDIndex.GetSize()); 
  //
  TObjArray *trackConds = 0;
  //
  fCountProlongationTrials = 0;
  fCountITSin = 0;
  fCountITSout = 0;
  fCountITSrefit = 0;
  //
  ResetSeedsPool();
  int nTrESD = esdEv->GetNumberOfTracks();
  AliInfo(Form("Will try to find prolongations for %d tracks",nTrESD));
  int nTrackCond = AliITSUReconstructor::GetRecoParam()->GetNTrackingConditions();
  if (nTrackCond<1) {
    if (!fDefTrackConds.GetEntriesFast()) {
      AliInfo("No tracking conditions found in recoparams, creating default one requesting all layers hit");
      CreateDefaultTrackCond();
    }
    trackConds = &fDefTrackConds;
    nTrackCond = trackConds->GetEntriesFast();
  } 
  else trackConds = AliITSUReconstructor::GetRecoParam()->GetTrackingConditions();
  //
  static Bool_t first = kTRUE;
  if (first) {
    AliITSUReconstructor::GetRecoParam()->Print();
    first = kFALSE;
  }
  fHypStore.Delete();
  if (fHypStore.GetSize()<nTrESD) fHypStore.Expand(nTrESD+100);
  //
  fITS->ProcessClusters();
  //
#ifdef  _FILL_CONTROL_HISTOS_
  FlagSplitClusters(); // tmp RS
#endif
  //
  // the tracks will be reconstructed in decreasing pt order, sort them
  if (fESDIndex.GetSize()<nTrESD) {
    fESDIndex.Set(nTrESD+200);
    esdTrPt.Set(nTrESD+200);
  }
  int* esdTrackIndex = fESDIndex.GetArray();
  float* trPt = esdTrPt.GetArray();
  for (int itr=nTrESD;itr--;) trPt[itr] = esdEv->GetTrack(itr)->Pt();
  Sort(nTrESD,trPt,esdTrackIndex,kTRUE);    
  //
  for (int icnd=0;icnd<nTrackCond;icnd++) {
    fCurrTrackCond = (AliITSUTrackCond*)trackConds->UncheckedAt(icnd);
    if (!fCurrTrackCond->IsInitDone()) fCurrTrackCond->Init();
    // select ESD tracks to propagate
    for (int itr=0;itr<nTrESD;itr++) {
      int trID = esdTrackIndex[itr];
      fCurrESDtrack = esdEv->GetTrack(trID);
      fCurrESDtrMClb = fCurrESDtrack->GetLabel();
      //
      if (!NeedToProlong(fCurrESDtrack)) continue;  // are we interested in this track?
      /*
	// if specific tracks should be checked, create a global array int wtc[] = {evITS*10000+trID, ...};
      Bool_t dbg = kFALSE;
      int nwtc = sizeof(wtc)/sizeof(int);

      for (int k=0;k<nwtc;k++) {
	if (wtc[k]==evID*10000+trID) {
	  dbg = kTRUE;
	  printf("\n\n\n\n\n\n\n");
	  printf("At esdTr: %d MC: %d\n",wtc[k],fCurrESDtrMClb);
	  printf("\n\n\n\n\n\n\n");
	  break;
	}
      }
      AliLog::SetClassDebugLevel("AliITSUTrackerGlo",dbg ? 10:0);
      */

      AliDebug(1,Form("Processing track %d(esd%d) | M=%.3f Pt=%.3f | MCLabel: %d",itr,trID,fCurrESDtrack->GetMass(kTRUE),fCurrESDtrack->Pt(),fCurrESDtrMClb));//RS
      FindTrack(fCurrESDtrack, trID);
    }   
    //
    if (AliDebugLevelClass()>+2) {
      AliInfo(Form("SeedsPool: %d, BookedUpTo: %d, free: %d",fSeedsPool.GetSize(),fSeedsPool.GetEntriesFast(),fNFreeSeeds));
      fHypStore.Print();
    }
    FinalizeHypotheses();
    //
    //AliLog::SetClassDebugLevel("AliITSUTrackerGlo",0);     // in case wtc array was defined, uncomment this
  }
  //
  AliInfo(Form("%d ITSin for %d tried TPC seeds out of %d ESD tracks\n",fCountITSin,fCountProlongationTrials,nTrESD));
  evID++;
  return 0;
}

//_________________________________________________________________________
Int_t AliITSUTrackerGlo::PropagateBack(AliESDEvent *esdEv)
{
  //
  // Do outward fits in ITS
  AliCodeTimerAuto("",0);
  //
  SetTrackingPhase(kPropBack);
  int nTrESD = esdEv->GetNumberOfTracks();
  AliDebug(1,Form("Will propagate back %d tracks",nTrESD));
  //
  double bz0 = GetBz();
  Double_t xyzTrk[3],xyzVtx[3]={GetX(),GetY(),GetZ()};
  AliITSUTrackHyp dummyTr;
  const double kWatchStep=10.; // for larger steps watch arc vs segment difference
  Double_t times[AliPID::kSPECIES];
  //
  for (int itr=0;itr<nTrESD;itr++) {
    fCurrESDtrack = esdEv->GetTrack(itr);
    fCurrESDtrMClb = fCurrESDtrack->GetLabel();
    // Start time integral and add distance from current position to vertex 
    if (fCurrESDtrack->IsOn(AliESDtrack::kITSout)) continue; // already done
    //
    fCurrESDtrack->GetXYZ(xyzTrk); 
    Double_t dst = 0.;     // set initial track lenght, tof
    {
      double dxs = xyzTrk[0] - xyzVtx[0];
      double dys = xyzTrk[1] - xyzVtx[1];
      double dzs = xyzTrk[2] - xyzVtx[2];
      // RS: for large segment steps d use approximation of cicrular arc s by
      // s = 2R*asin(d/2R) = d/p asin(p) \approx d/p (p + 1/6 p^3) = d (1+1/6 p^2)
      // where R is the track radius, p = d/2R = 2C*d (C is the abs curvature)
      // Hence s^2/d^2 = (1+1/6 p^2)^2
      dst = dxs*dxs + dys*dys;
      if (dst > kWatchStep*kWatchStep) { // correct circular part for arc/segment factor
	double crv = Abs(fCurrESDtrack->GetC(bz0));
	double fcarc = 1.+crv*crv*dst/6.;
	dst *= fcarc*fcarc;
      }
      dst += dzs*dzs;
      dst = Sqrt(dst); 
    }
    //    
    fCurrESDtrack->SetStatus(AliESDtrack::kTIME);
    //
    if (!fCurrESDtrack->IsOn(AliESDtrack::kITSin)) { // case of tracks w/o ITS prolongation: just set the time integration
      dummyTr.AliExternalTrackParam::operator=(*fCurrESDtrack);
      dummyTr.StartTimeIntegral();
      dummyTr.AddTimeStep(dst);
      dummyTr.GetIntegratedTimes(times); 
      fCurrESDtrack->SetIntegratedTimes(times);
      fCurrESDtrack->SetIntegratedLength(dummyTr.GetIntegratedLength());
      continue;
    }
    //
    fCurrHyp = GetTrackHyp(itr);
    fCurrMass = fCurrHyp->GetMass();
    fCurrHyp->StartTimeIntegral();
    fCurrHyp->AddTimeStep(dst);
    fCurrHyp->ResetCovariance(10000);
    double chi2 = RefitTrack(fCurrHyp,fITS->GetRMax());
    if (chi2>0) { // propagate to exit from the ITS/TPC screen
      int ndf = fCurrHyp->GetWinner()->GetNLayersHit()*2-5;
      if (ndf>0) chi2 /= ndf;
      fCurrHyp->SetChi2(chi2);
      UpdateESDTrack(fCurrHyp,AliESDtrack::kITSout);
      fCountITSout++;
    }
    else {
      AliDebug(2,Form("Refit Failed for track %d | ESDtrack#%d (MClb:%d)",itr,fCurrESDtrack->GetID(),fCurrESDtrMClb));
      //fCurrHyp->AliExternalTrackParam::Print();
      //fCurrHyp->GetWinner()->Print();
    }
    //
  }
  //
  AliInfo(Form("%d ITSout in %d ITSin tracks for %d tried TPC seeds out of %d ESD tracks\n",
	       fCountITSout,fCountITSin,fCountProlongationTrials,nTrESD));
  //
  return 0;
}

//_________________________________________________________________________
Int_t AliITSUTrackerGlo::RefitInward(AliESDEvent *esdEv)
{
  //
  // refit the tracks inward, using current cov.matrix
  AliCodeTimerAuto("",0);
  //
  SetTrackingPhase(kRefitInw);
  Int_t nTrESD = esdEv->GetNumberOfTracks();
  //  AliLog::SetClassDebugLevel("AliITSUTrackerGlo",10);

  AliDebug(1,Form("Will refit inward %d tracks",nTrESD));
  //
  for (int itr=0;itr<nTrESD;itr++) {
    fCurrESDtrack = esdEv->GetTrack(itr);
    fCurrESDtrMClb = fCurrESDtrack->GetLabel();
    // Start time integral and add distance from current position to vertex 
    UInt_t trStat = fCurrESDtrack->GetStatus();
    if ( !(trStat & AliESDtrack::kITSout) ) continue;
    if (   trStat & AliESDtrack::kITSrefit ) continue; // already done
    if (  (trStat & AliESDtrack::kTPCout) && !(trStat & AliESDtrack::kTPCrefit) ) continue;
    //
    fCurrHyp = GetTrackHyp(itr);
    fCurrHyp->AliExternalTrackParam::operator=(*fCurrESDtrack);  // fetch current ESDtrack kinematics
    fCurrMass = fCurrHyp->GetMass();
    //
    double chi2 = RefitTrack(fCurrHyp,fITS->GetRMin());
    if (chi2>0) { // propagate up to inside radius of the beam pipe      
      fCurrHyp->SetChi2(chi2);
      UpdateESDTrack(fCurrHyp,AliESDtrack::kITSrefit);
      fCountITSrefit++;
    }
    else {
      AliDebug(2,Form("Refit Failed for track %d |ESDtrack#%d (MClb:%d)",itr,fCurrESDtrack->GetID(),fCurrESDtrMClb));
    }
  }    
  //
  AliInfo(Form("%d ITSrefit in %d ITSout in %d ITSin tracks for %d tried TPC seeds out of %d ESD tracks\n",
	       fCountITSrefit,fCountITSout,fCountITSin,fCountProlongationTrials,nTrESD));
  //
  //  AliLog::SetClassDebugLevel("AliITSUTrackerGlo",0);
  return 0;
}

//_________________________________________________________________________
Int_t AliITSUTrackerGlo::LoadClusters(TTree * treeRP)
{
  // read from tree (if pointer provided) or directly from the ITS reco interface
  //
  return fReconstructor->LoadClusters(treeRP);
} 

//_________________________________________________________________________
void AliITSUTrackerGlo::UnloadClusters()
{
  //
  // To be implemented 
  //
  
  Info("UnloadClusters","To be implemented");
} 
//_________________________________________________________________________
AliCluster * AliITSUTrackerGlo::GetCluster(Int_t /*index*/) const
{
  //
  // To be implemented 
  //
  
  Info("GetCluster","To be implemented");
  return 0x0;
} 

//_________________________________________________________________________
Bool_t AliITSUTrackerGlo::NeedToProlong(AliESDtrack* esdTr)
{
  // do we need to match this track to ITS?
  //
  static double bz = GetBz();
  if (!esdTr->IsOn(AliESDtrack::kTPCin) ||
      esdTr->IsOn(AliESDtrack::kTPCout) ||
      esdTr->IsOn(AliESDtrack::kITSin)  ||
      esdTr->GetKinkIndex(0)>0) return kFALSE;
  //
  if (esdTr->Pt()<AliITSUReconstructor::GetRecoParam()->GetMinPtForProlongation()) return kFALSE;
  //
  float dtz[2];
  esdTr->GetDZ(GetX(),GetY(),GetZ(),bz,dtz); 
  // if track is not V0 candidata but has large offset wrt IP, reject it. RS TOCHECK
  if ( !(esdTr->GetV0Index(0)>0 && dtz[0]>AliITSUReconstructor::GetRecoParam()->GetMaxDforV0dghtrForProlongation()) 
       && (Abs(dtz[0])>AliITSUReconstructor::GetRecoParam()->GetMaxDForProlongation() ||
	   Abs(dtz[1])>AliITSUReconstructor::GetRecoParam()->GetMaxDZForProlongation())) return kFALSE;
  //
  //  if (esdTr->Pt()<3) return kFALSE;//RS
  return kTRUE;
}

//_________________________________________________________________________
void AliITSUTrackerGlo::FindTrack(AliESDtrack* esdTr, Int_t esdID)
{
  // find prolongaion candidates finding for single seed
  //
  AliITSUSeed seedUC;  // copy of the seed from the upper layer
  AliITSUSeed seedT;   // transient seed between the seedUC and new prolongation hypothesis
  //
  AliITSUTrackHyp* hypTr = InitHypothesis(esdTr,esdID);  // initialize prolongations hypotheses tree
  if (!hypTr || hypTr->GetSkip()) return;
  //
  fCurrHyp = fWorkHyp;
  fCurrHyp->InitFrom(hypTr);
  //
  AliITSURecoSens *hitSens[AliITSURecoSens::kNNeighbors+1];
  //
  TObjArray clArr; // container for transfer of clusters matching to seed
  //
  for (int ila=fNLrActive;ila--;) {
    fCurrActLrID = ila;
    fCurrLayer = fITS->GetLayerActive(ila);
    Bool_t noClSharing = fCurrTrackCond->GetClSharing(ila)==0;
    int ilaUp = ila+1;                         // prolong seeds from layer above
    //
    // for the outermost layer the seed is created from the ESD track
    int nSeedsUp = (ilaUp==fNLrActive) ? 1 : fCurrHyp->GetNSeeds(ilaUp);
    int maxNBranches   = fCurrTrackCond->GetMaxBranches(ila);
    int maxNCandidates = fCurrTrackCond->GetMaxCandidates(ila);
    //
    for (int isd=0;isd<nSeedsUp;isd++) {
      AliITSUSeed* seedU;
      if (ilaUp==fNLrActive) {
	seedU = 0;
	seedUC.InitFromSeed(fCurrHyp->GetTPCSeed()); // init with TPC seed from ref.R
      }
      else {
	seedU = fCurrHyp->GetSeed(ilaUp,isd);  // seed on prev.active layer to prolong	
	if (seedU->IsKilled()) continue;
	seedUC = *seedU;                       // its copy will be prolonged
	seedUC.SetParent(seedU);	
      }
      seedUC.ResetFMatrix();                    // reset the matrix for propagation to next layer
      // go till next active layer
      AliDebug(2,Form("working on Lr:%d Seed:%d of %d for esdID=%d (MClb:%d) | pT=%.3f",ila,isd,nSeedsUp,esdID,fCurrESDtrMClb,seedUC.Pt()));
      if (!TransportToLayer(&seedUC, fITS->GetLrIDActive(ilaUp), fITS->GetLrIDActive(ila)) ) { // external seed already prolonged
	//
	AliDebug(2,Form("Transport failed | esdID=%d (MClb:%d)",esdID,fCurrESDtrMClb));
	// Check if the seed satisfies to track definition
	if (NeedToKill(&seedUC,kTransportFailed) && seedU) KillSeed(seedU,kTRUE);
	continue; // RS TODO: decide what to do with tracks stopped on higher layers w/o killing
      }
      if (!GetRoadWidth(&seedUC, ila)) { // failed to find road width on the layer
	if (NeedToKill(&seedUC,kRWCheckFailed) && seedU) KillSeed(seedU,kTRUE);
	continue;
      }
      /*
      //RS toremove
      int mcquest = -1;
      if (!seedUC.ContainsFake() && AliDebugLevelClass()>2) {
	mcquest = fCurrESDtrMClb;
	seedUC.Print("etp");
	printf("FSParams: "); for (int ip=0;ip<kNTrImpData;ip++) printf("%+e ",fTrImpData[ip]); printf("\n");
      }
      //
      int nsens = fCurrLayer->FindSensors(&fTrImpData[kTrPhi0], hitSens, mcquest);  // find detectors which may be hit by the track
      */
      int nsens = fCurrLayer->FindSensors(&fTrImpData[kTrPhi0], hitSens);  // find detectors which may be hit by the track
      AliDebug(2,Form("Will check %d sensors on lr:%d | esdID=%d (MClb:%d)",nsens,ila,esdID,fCurrESDtrMClb));
      //
      seedUC.SetLr(ila);
      //
      double bz = GetBz();
      for (int isn=nsens;isn--;) {
	AliITSURecoSens* sens = hitSens[isn];
	int ncl = sens->GetNClusters();
	if (!ncl) continue;
	seedT = seedUC;
	//
	// We need to propagate the seed to sensor on fCurrLayer staying in the frame of the sensor from prev.layer,
	// since the transport matrix should be defined in this frame.
	double xs; // X in the TF of current seed, corresponding to intersection with sensor plane
	if (!seedT.GetTrackingXAtXAlpha(sens->GetXTF(),sens->GetPhiTF(),bz, xs)) {
	  if (AliDebugLevelClass()>2) {
	    printf("Failed on GetTrackingXAtXAlpha: X=%.4f alp=%.3f\n",sens->GetXTF(),sens->GetPhiTF());
	    seedT.Print("etp");
	  }
	  continue;
	}
	if (xs<seedT.GetX()) {
	  if (!PropagateSeed(&seedT,xs,fCurrMass)) continue;
	}
	else { // some low precision tracks may hit the sensor plane outside of the layer radius
	  if (AliDebugLevelClass()>2) {
	    if (!seedT.ContainsFake()) {
	      printf("WRONG PROP on L%d, sens%d of %d: %.4f > %.4f\n",ila,isn,nsens,xs,seedT.GetX());
	      sens->Print();
	      seedT.Print("etp");	    
	    }
	  }
	  if (!seedT.PropagateParamOnlyTo(xs,bz)) continue;
	}
	//	if (!seedT.PropagateToX(xs,bz)) continue;
	//	if (!seedT.Rotate(sens->GetPhiTF())) continue;
	if (!seedT.RotateToAlpha(sens->GetPhiTF())) continue;
	//
	int clID0 = sens->GetFirstClusterId();
	for (int icl=ncl;icl--;) { // don't change the order, clusters are sorted
	  //AliLog::SetClassDebugLevel("AliITSUTrackerGlo",10);
	  int clID = clID0 + icl;
	  if (noClSharing && fCurrLayer->GetCluster(clID)->IsClusterUsed()) continue;
	  int res = CheckCluster(&seedT,ila,clID0+icl);
	  //AliLog::SetClassDebugLevel("AliITSUTrackerGlo", 0);
	  //
	  if (res==kStopSearchOnSensor) break;     // stop looking on this sensor
	  if (res==kClusterNotMatching) continue;  // cluster does not match
	  // cluster is matching and it was added to the hypotheses tree
	}
      }
      // cluster search is done. Do we need to have a version of this seed skipping current layer
      if (!NeedToKill(&seedUC,kMissingCluster)) {
	AliITSUSeed* seedSkp = NewSeedFromPool(&seedUC);
	double penalty = -fCurrTrackCond->GetMissPenalty(ila);
	// to do: make penalty to account for probability to miss the cluster for good reason
	seedSkp->SetChi2Cl(penalty);
	AddSeedBranch(seedSkp);
	//	AddProlongationHypothesis(seedSkp,ila);      
      }
      // transfer the new branches of the seed to the hypothesis container
      if (fNBranchesAdded) ValidateAllowedBranches(maxNBranches);
      //
    }
    if (fNCandidatesAdded) ValidateAllowedCandidates(ila,maxNCandidates);
    //    ((TObjArray*)fCurrHyp->GetLayerSeeds(ila))->Sort();
    if (AliDebugLevelClass()>2) { //RS
      printf(">>> All hypotheses on lr %d: \n",ila);
      for (int ih=0;ih<fCurrHyp->GetNSeeds(ila);ih++) {printf(" #%3d ",ih); fCurrHyp->GetSeed(ila,ih)->Print();}
    }
    //
    /*
    for (int ih=0;ih<fCurrHyp->GetNSeeds(ila);ih++) {
      if (ila!=0) continue;
      double vecL[5] = {0};
      double matL[15] = {0};
      AliITSUSeed* sp = fCurrHyp->GetSeed(ila,ih);
      while(sp->GetParent()) {
	sp->Smooth(vecL,matL);
	if (sp->GetLayerID()>=fNLrActive-1) break;
	sp = (AliITSUSeed*)sp->GetParent();
      }
      */
  }
  //
  SaveReducedHypothesesTree(hypTr);
  if (AliDebugLevelClass()>1) {
    printf("\nSaved hypotheses for esdTrack %d (MCLab:%d)\n",esdID,fCurrESDtrMClb);
    hypTr->Print("l");
  }
  fCurrHyp = 0;
  //
}

//_________________________________________________________________________
AliITSUTrackHyp* AliITSUTrackerGlo::InitHypothesis(AliESDtrack *esdTr, Int_t esdID)
{
  // init prolongaion candidates finding for single seed
  AliITSUTrackHyp* hyp = GetTrackHyp(esdID);
  if (hyp) return hyp;
  //
  fCountProlongationTrials++;
  //
  fCurrMass = esdTr->GetMass();
  if (fCurrMass<kPionMass*0.9) fCurrMass = kPionMass; // don't trust to mu, e identification from TPCin
  //
  hyp = new AliITSUTrackHyp(fNLrActive);
  hyp->SetESDTrack(esdTr);
  hyp->SetUniqueID(esdID);
  hyp->SetMass(fCurrMass);
  hyp->SetTPCSeed( new AliExternalTrackParam(*esdTr) );
  SetTrackHyp(hyp,esdID);

  if (!TransportToLayer(hyp->GetTPCSeed(),fITS->GetNLayers(), fITS->GetLrIDActive(fNLrActive-1), fITS->GetRITSTPCRef())) hyp->SetSkip(); // propagate to outer R of ITS
  //
  return hyp;
  // TO DO
}

//_________________________________________________________________________
Bool_t AliITSUTrackerGlo::TransportToLayer(AliITSUSeed* seed, Int_t lFrom, Int_t lTo, Double_t rLim)
{
  // transport seed from layerFrom to the entrance (along the direction of the track) of layerTo or to rLim (if>0), wathever is closer
  //  
  //
  if (lTo==lFrom) AliFatal(Form("was called with lFrom=%d lTo=%d",lFrom,lTo));
  //
  int dir = lTo > lFrom ? 1:-1;
  AliITSURecoLayer* lrFr = fITS->GetLayer(lFrom); // this can be 0 when extrapolation from TPC to ITS is requested
  Bool_t checkFirst = kTRUE;
  Bool_t limReached = kFALSE;
  while(lFrom!=lTo) {
    if (lrFr) {
      if (!GoToExitFromLayer(seed,lrFr,dir,checkFirst))	return kFALSE; // go till the end of current layer
      checkFirst = kFALSE;
    }
    AliITSURecoLayer* lrTo =  fITS->GetLayer( (lFrom+=dir) );
    if (!lrTo) AliFatal(Form("Layer %d does not exist",lFrom));
    //
    // go the entrance of the layer, assuming no materials in between
    double xToGo = lrTo->GetR(-dir);
    if (rLim>0) {
      if (dir>0) {
	if (rLim<xToGo) {xToGo = rLim; limReached = kTRUE;}
      }
      else {
	if (rLim>xToGo) {xToGo = rLim; limReached = kTRUE;}
      }
    }
    //    double xts = xToGo;
    if (!seed->GetXatLabR(xToGo,xToGo,GetBz(),dir)) {
      //printf("FailHere1: %f %f %d\n",xts,xToGo,dir);
      //seed->Print("etp");
      //      
      return kFALSE;
    }
    AliDebug(2,Form("go in dir=%d to R=%.4f(X:%.4f)",dir,lrTo->GetR(-dir), xToGo));
    if (!PropagateSeed(seed,xToGo,fCurrMass,100, kFALSE )) {
      //printf("FailHere2: %f %f %d\n",xts,xToGo,dir);
      //seed->Print("etp");
      return kFALSE;
    }
    lrFr = lrTo;
    if (limReached) break;
  }
  return kTRUE;
  //
}

//_________________________________________________________________________
Bool_t AliITSUTrackerGlo::TransportToLayer(AliExternalTrackParam* seed, Int_t lFrom, Int_t lTo, Double_t rLim)
{
  // transport track from layerFrom to the entrance of layerTo or to rLim (if>0), wathever is closer
  //  
  if (lTo==lFrom) AliFatal(Form("was called with lFrom=%d lTo=%d",lFrom,lTo));
  //
  int dir = lTo > lFrom ? 1:-1;
  AliITSURecoLayer* lrFr = fITS->GetLayer(lFrom); // this can be 0 when extrapolation from TPC to ITS is requested
  Bool_t checkFirst = kTRUE;
  Bool_t limReached = kFALSE;
  while(lFrom!=lTo) {
    if (lrFr) {
      if (!GoToExitFromLayer(seed,lrFr,dir,checkFirst)) return kFALSE; // go till the end of current layer
      checkFirst = kFALSE;
    }
    AliITSURecoLayer* lrTo =  fITS->GetLayer( (lFrom+=dir) );
    if (!lrTo) AliFatal(Form("Layer %d does not exist",lFrom));
    //
    // go the entrance of the layer, assuming no materials in between
    double xToGo = lrTo->GetR(-dir);
    if (rLim>0) {
      if (dir>0) {
	if (rLim<xToGo) {xToGo = rLim; limReached = kTRUE;}
      }
      else {
	if (rLim>xToGo) {xToGo = rLim; limReached = kTRUE;}
      }
    }
    //    double xts = xToGo;
    if (!seed->GetXatLabR(xToGo,xToGo,GetBz(),dir)) {
      //      printf("FailHere1: %f %f %d\n",xts,xToGo,dir);
      //      seed->Print("etp");
      return kFALSE;
    }
    AliDebug(2,Form("go in dir=%d to R=%.4f(X:%.4f)",dir,lrTo->GetR(-dir), xToGo));
    if (!PropagateSeed(seed,xToGo,fCurrMass,100, kFALSE )) {
      //printf("FailHere2: %f %f %d\n",xts,xToGo,dir);
      //seed->Print("etp");
      return kFALSE;
    }
    lrFr = lrTo;
    if (limReached) break;
  }
  return kTRUE;
  //
}

//_________________________________________________________________________
Bool_t AliITSUTrackerGlo::TransportToLayerX(AliExternalTrackParam* seed, Int_t lFrom, Int_t lTo, Double_t xStop)
{
  // transport track from layerFrom to the entrance of layerTo but do not pass control parameter X
  //  
  if (lTo==lFrom) AliFatal(Form("was called with lFrom=%d lTo=%d",lFrom,lTo));
  //
  int dir = lTo > lFrom ? 1:-1;
  AliITSURecoLayer* lrFr = fITS->GetLayer(lFrom); // this can be 0 when extrapolation from TPC to ITS is requested
  Bool_t checkFirst = kTRUE;
  while(lFrom!=lTo) {
    if (lrFr) {
      if (!GoToExitFromLayer(seed,lrFr,dir,checkFirst)) return kFALSE; // go till the end of current layer
      checkFirst = kFALSE;
    }
    AliITSURecoLayer* lrTo =  fITS->GetLayer( (lFrom+=dir) );
    if (!lrTo) AliFatal(Form("Layer %d does not exist",lFrom));
    //
    // go the entrance of the layer, assuming no materials in between
    double xToGo = lrTo->GetR(-dir); // R of the entrance to layer
    //
    //    double xts = xToGo;
    if (!seed->GetXatLabR(xToGo,xToGo,GetBz(),dir)) {
      //      printf("FailHere1: %f %f %d\n",xts,xToGo,dir);
      //      seed->Print("etp");
      return kFALSE;
    }
    if ( (dir>0&&xToGo>xStop) || (dir<0&&xToGo<xStop) ) xToGo = xStop;
    //
    AliDebug(2,Form("go in dir=%d to R=%.4f(X:%.4f)",dir,lrTo->GetR(-dir), xToGo));
    if (!PropagateSeed(seed,xToGo,fCurrMass,100, kFALSE )) {
      //printf("FailHere2: %f %f %d\n",xts,xToGo,dir);
      //seed->Print("etp");
      return kFALSE;
    }
    lrFr = lrTo;
  }
  return kTRUE;
  //
}

//_________________________________________________________________________
Bool_t AliITSUTrackerGlo::GoToExitFromLayer(AliITSUSeed* seed, AliITSURecoLayer* lr, Int_t dir, Bool_t check)
{
  // go to the exit from lr in direction dir, applying material corrections in steps specific for this layer
  // If check is requested, do this only provided the track has not exited the layer already
  double xToGo = lr->GetR(dir);
  if (check) { // do we need to track till the surface of the current layer ?
    double curR2 = seed->GetX()*seed->GetX() + seed->GetY()*seed->GetY(); // current radius
    AliDebug(3,Form(" dir:%d Cur: %e Tgt: %e",dir,Sqrt(curR2),xToGo));
    if      (dir>0) { if (curR2-xToGo*xToGo>-fgkToler) return kTRUE; } // on the surface or outside of the layer
    else if (dir<0) { if (xToGo*xToGo-curR2>-fgkToler) return kTRUE; } // on the surface or outside of the layer
  }
  if (!seed->GetXatLabR(xToGo,xToGo,GetBz(),dir)) return kFALSE;
  // go via layer to its boundary, applying material correction.
  if (!PropagateSeed(seed,xToGo,fCurrMass, lr->GetMaxStep())) return kFALSE;
  //
  return kTRUE;
  //
}

//_________________________________________________________________________
Bool_t AliITSUTrackerGlo::GoToExitFromLayer(AliExternalTrackParam* seed, AliITSURecoLayer* lr, Int_t dir, Bool_t check)
{
  // go to the exit from lr in direction dir, applying material corrections in steps specific for this layer
  // If check is requested, do this only provided the track has not exited the layer already
  double xToGo = lr->GetR(dir);
  if (check) { // do we need to track till the surface of the current layer ?
    double curR2 = seed->GetX()*seed->GetX() + seed->GetY()*seed->GetY(); // current radius
    if      (dir>0) { if (curR2-xToGo*xToGo>-fgkToler) return kTRUE; } // on the surface or outside of the layer
    else if (dir<0) { if (xToGo*xToGo-curR2>-fgkToler) return kTRUE; } // on the surface or outside of the layer
  }
  AliDebug(2,Form(" dir=%d : from R=%.4f -> R=%.4f",dir,Sqrt(seed->GetX()*seed->GetX() + seed->GetY()*seed->GetY()), xToGo));
  if (!seed->GetXatLabR(xToGo,xToGo,GetBz(),dir)) return kFALSE;
  // go via layer to its boundary, applying material correction.
  if (!PropagateSeed(seed,xToGo,fCurrMass, lr->GetMaxStep())) return kFALSE;
  //
  return kTRUE;
  //
}


//_________________________________________________________________________
Bool_t AliITSUTrackerGlo::GoToEntranceToLayer(AliITSUSeed* seed, AliITSURecoLayer* lr, Int_t dir, Bool_t check)
{
  // go to the entrance of lr in direction dir, w/o applying material corrections.
  // If check is requested, do this only provided the track did not reach the layer already
  double xToGo = lr->GetR(-dir);
  if (check) { // do we need to track till the surface of the current layer ?
    double curR2 = seed->GetX()*seed->GetX() + seed->GetY()*seed->GetY(); // current radius
    if      (dir>0) { if (curR2-xToGo*xToGo>-fgkToler) return kTRUE; } // already passed
    else if (dir<0) { if (xToGo*xToGo-curR2>-fgkToler) return kTRUE; } // already passed
  }
  if (!seed->GetXatLabR(xToGo,xToGo,GetBz(),dir)) return kFALSE;
  // go via layer to its boundary, applying material correction.
  if (!PropagateSeed(seed,xToGo,fCurrMass, 100, kFALSE)) return kFALSE;
  return kTRUE;
  //
}

//_________________________________________________________________________
Bool_t AliITSUTrackerGlo::GoToEntranceToLayer(AliExternalTrackParam* seed, AliITSURecoLayer* lr, Int_t dir, Bool_t check)
{
  // go to the entrance of lr in direction dir, w/o applying material corrections.
  // If check is requested, do this only provided the track did not reach the layer already
  double xToGo = lr->GetR(-dir);
  if (check) { // do we need to track till the surface of the current layer ?
    double curR2 = seed->GetX()*seed->GetX() + seed->GetY()*seed->GetY(); // current radius
    if      (dir>0) { if (curR2-xToGo*xToGo>-fgkToler) return kTRUE; } // already passed
    else if (dir<0) { if (xToGo*xToGo-curR2>-fgkToler) return kTRUE; } // already passed
  }
  if (!seed->GetXatLabR(xToGo,xToGo,GetBz(),dir)) return kFALSE;
  // go via layer to its boundary, applying material correction.
  if (!PropagateSeed(seed,xToGo,fCurrMass, 100, kFALSE)) return kFALSE;
  return kTRUE;
  //
}

//_________________________________________________________________________
Bool_t AliITSUTrackerGlo::GetRoadWidth(AliITSUSeed* seed, int ilrA)
{
  // calculate road width in terms of phi and z for the track which MUST be on the external radius of the layer
  // as well as some aux info
  double bz = GetBz();
  AliITSURecoLayer* lrA = fITS->GetLayerActive(ilrA);
  seed->GetXYZ(&fTrImpData[kTrXIn]);    // lab position at the entrance from above
  static AliExternalTrackParam sc;   // seed copy for manipulations
  sc = *seed;
  //
  fTrImpData[kTrPhiIn] = ATan2(fTrImpData[kTrYIn],fTrImpData[kTrXIn]);
  if (!sc.Rotate(fTrImpData[kTrPhiIn])) return kFALSE; // go to the frame of the entry point into the layer
  double dr  = lrA->GetDR();                              // approximate X dist at the inner radius
  if (!sc.GetXYZAt(sc.GetX()-dr, bz, fTrImpData + kTrXOut)) {
    // special case: track does not reach inner radius, might be tangential
    double r = sc.GetD(0,0,bz);
    double x;
    if (!sc.GetXatLabR(r,x,bz,-1)) return kFALSE;
    dr = Abs(sc.GetX() - x);
    if (!sc.GetXYZAt(x, bz, fTrImpData + kTrXOut)) return kFALSE;
  }
  //
  fTrImpData[kTrPhiOut] = ATan2(fTrImpData[kTrYOut],fTrImpData[kTrXOut]);
  double sgy = sc.GetSigmaY2() + dr*dr*sc.GetSigmaSnp2() + AliITSUReconstructor::GetRecoParam()->GetSigmaY2(ilrA);
  double sgz = sc.GetSigmaZ2() + dr*dr*sc.GetSigmaTgl2() + AliITSUReconstructor::GetRecoParam()->GetSigmaZ2(ilrA);
  sgy = Sqrt(sgy)*fCurrTrackCond->GetNSigmaRoadY(ilrA);
  sgz = Sqrt(sgz)*fCurrTrackCond->GetNSigmaRoadZ(ilrA);
  double dphi0 = 0.5*Abs(fTrImpData[kTrPhiOut]-fTrImpData[kTrPhiIn]);
  double phi0  = 0.5*(fTrImpData[kTrPhiOut]+fTrImpData[kTrPhiIn]);
  if ( dphi0>(0.5*Pi()) ) {
    // special case of angles around pi 
    dphi0 = Abs(phi0);    
    phi0  += Pi();
  }

  fTrImpData[kTrPhi0] = phi0;
  fTrImpData[kTrZ0]   = 0.5*(fTrImpData[kTrZOut]+fTrImpData[kTrZIn]);
  dphi0 += sgy/lrA->GetR();
  fTrImpData[kTrDPhi] =  dphi0<PiOver2() ? dphi0 : PiOver2();
  fTrImpData[kTrDZ]   = 0.5*Abs(fTrImpData[kTrZOut]-fTrImpData[kTrZIn])   + sgz;
  //  
  return kTRUE;
}

//________________________________________
void AliITSUTrackerGlo::ResetSeedsPool()
{
  // mark all seeds in the pool as unused
  AliDebug(-1,Form("CurrentSize: %d, BookedUpTo: %d, free: %d",fSeedsPool.GetSize(),fSeedsPool.GetEntriesFast(),fNFreeSeeds));
  fNFreeSeeds = 0;
  fSeedsPool.Clear(); // seeds don't allocate memory
}


//________________________________________
void AliITSUTrackerGlo::MarkSeedFree(AliITSUSeed *sd) 
{
  // account that this seed is "deleted" 
  int id = sd->GetPoolID();
  if (id<0) {
    AliError(Form("Freeing of seed %p NOT from the pool is requested",sd)); 
    return;
  }
  //  AliInfo(Form("%d %p",id, seed));
  fSeedsPool.RemoveAt(id);
  if (fFreeSeedsID.GetSize()<=fNFreeSeeds) fFreeSeedsID.Set( 2*fNFreeSeeds + 100 );
  fFreeSeedsID.GetArray()[fNFreeSeeds++] = id;
}

//_________________________________________________________________________
Int_t AliITSUTrackerGlo::CheckCluster(AliITSUSeed* track, Int_t lr, Int_t clID) 
{
  // Check if the cluster (in tracking frame!) is matching to track. 
  // The track must be already propagated to sensor tracking frame.
  // Returns:  kStopSearchOnSensor if the search on given sensor should be stopped, 
  //           kClusterMatching    if the cluster is matching
  //           kClusterMatching    otherwise
  //
  const double kTolerX = 5e-4;
  //  AliCluster *cl = fITS->GetLayerActive(lr)->GetCluster(clID);
  AliCluster *cl = fCurrLayer->GetCluster(clID);
  //
  Bool_t goodCl = kFALSE;
  int currLabel = Abs(fCurrESDtrMClb);
  //
  if (cl->GetLabel(0)>=0) {
    for (int i=0;i<3;i++) if (cl->GetLabel(i)>=0 && cl->GetLabel(i)==currLabel) {goodCl = kTRUE; break;}
  }
  Bool_t goodSeed = !track->ContainsFake();
  //
  if (TMath::Abs(cl->GetX())>kTolerX) { // if due to the misalingment X is large, propagate track only
    if (!track->PropagateParamOnlyTo(track->GetX()+cl->GetX(),GetBz())) {
      if (goodCl&&goodSeed && AliDebugLevelClass()>2 ) {
	AliDebug(2,Form("Lost good cl on L:%d failed propagation. |ESDtrack#%d (MClb:%d)",lr,fCurrESDtrack->GetID(),fCurrESDtrMClb)); 
	track->Print("etp");
	cl->Print();
      }
      return kStopSearchOnSensor; // propagation failed, seedT is intact
    }
  }
  double dy = cl->GetY()-track->GetY();
  double dz = cl->GetZ()-track->GetZ();
  //
#ifdef  _FILL_CONTROL_HISTOS_
  int hcOffs = (1+fTrackPhase)*kHistosPhase + lr;
  double htrPt=-1;
  if (goodCl && (((AliITSUClusterPix*)cl)->GetNPix()>1 || !((AliITSUClusterPix*)cl)->IsSplit()) && goodSeed && fCHistoArr /* && track->GetChi2Penalty()<1e-5*/) {
    htrPt = track->Pt();
    ((TH2*)fCHistoArr->At(kHResY+hcOffs))->Fill(htrPt,dy);
    ((TH2*)fCHistoArr->At(kHResZ+hcOffs))->Fill(htrPt,dz);
    double errY = track->GetSigmaY2();
    double errZ = track->GetSigmaZ2();
    if (errY>0) ((TH2*)fCHistoArr->At(kHResYP+hcOffs))->Fill(htrPt,dy/Sqrt(errY));
    if (errZ>0) ((TH2*)fCHistoArr->At(kHResZP+hcOffs))->Fill(htrPt,dz/Sqrt(errZ));
  }
#endif  
  //
  double dy2 = dy*dy;
  double tol2 = (track->GetSigmaY2() + AliITSUReconstructor::GetRecoParam()->GetSigmaY2(lr))*
    fCurrTrackCond->GetNSigmaRoadY(lr)*fCurrTrackCond->GetNSigmaRoadY(lr); // RS TOOPTIMIZE
  if (dy2>tol2) {                          // the clusters are sorted in Z(col) then in Y(row). 
    if (goodCl&&goodSeed && AliDebugLevelClass()>2) {    
      AliDebug(2,Form("Lost good cl: dy2=%e > tol2=%e |ESDtrack#%d (MClb:%d)",dy2,tol2,fCurrESDtrack->GetID(),fCurrESDtrMClb)); 
      track->Print("etp");
      cl->Print();
      PrintSeedClusters(track);
    }
    // clusters are sorted in increasing Y and the loop goes from last (highers Y) to 1st.
    // if the track has too large y for this cluster (dy<0) it will be so for all other clusters of the sensor
    if (dy<0) return kStopSearchOnSensor;  // No chance that other cluster of this sensor will match (all Y's will be even larger)
    else      return kClusterNotMatching;   // Other clusters may match
  }
  double dz2 = dz*dz;
  tol2 = (track->GetSigmaZ2() + AliITSUReconstructor::GetRecoParam()->GetSigmaZ2(lr))*
    fCurrTrackCond->GetNSigmaRoadZ(lr)*fCurrTrackCond->GetNSigmaRoadZ(lr); // RS TOOPTIMIZE
  if (dz2>tol2) {
    if (goodCl&&goodSeed && AliDebugLevelClass()>2) {
      AliDebug(2,Form("Lost good cl on L:%d : dz2=%e > tol2=%e |ESDtrack#%d (MClb:%d)",lr,dz2,tol2,fCurrESDtrack->GetID(),fCurrESDtrMClb)); 
      track->Print("etp");
      cl->Print();
      PrintSeedClusters(track);
    }
    return kClusterNotMatching; // Other clusters may match
  }
  //
  // check chi2
  Double_t p[2]={cl->GetY(), cl->GetZ()};
  Double_t cov[3]={cl->GetSigmaY2(), cl->GetSigmaYZ(), cl->GetSigmaZ2()};
  double chi2 = track->GetPredictedChi2(p,cov);
  //
#ifdef  _FILL_CONTROL_HISTOS_
  if (htrPt>0) {
    ((TH2*)fCHistoArr->At(kHChi2Cl+hcOffs))->Fill(htrPt,chi2);
  }
#endif
  //
  if (chi2>fCurrTrackCond->GetMaxTr2ClChi2(lr)) {
    if (goodCl&&goodSeed && AliDebugLevelClass()>2) {
      AliDebug(2,Form("Lost good cl on L:%d : Chi2=%e > Chi2Max=%e |dy: %+.3e dz: %+.3e |ESDtrack#%d (MClb:%d)\n",
		      lr,chi2,fCurrTrackCond->GetMaxTr2ClChi2(lr),dy,dz,fCurrESDtrack->GetID(),fCurrESDtrMClb)); 
      track->Print("etp");
      cl->Print("");
      PrintSeedClusters(track);
    }
    return kClusterNotMatching;
  }
  //
  track = NewSeedFromPool(track);  // input track will be reused, use its clone for updates
  if (!track->Update()) {
    if (goodCl&&goodSeed && AliDebugLevelClass()>2) {
      AliDebug(2,Form("Lost good cluster on L:%d : failed to update",lr));
      track->Print("etp");
      cl->Print("");
      PrintSeedClusters(track);
    }
    MarkSeedFree(track);
    return kClusterNotMatching;
  }
  track->SetChi2Cl(chi2);
  track->SetLrClusterID(lr,clID);
  //  cl->IncreaseClusterUsage(); // do this only for winners
  //
  track->SetFake(!goodCl);
  //
  AliDebug(2,Form("AddCl(%d) Cl%d lr:%d: dY:%+8.4f dZ:%+8.4f (MC: %5d %5d %5d) |Chi2=%f(%c)| ",
	       goodCl,clID,lr,dy,dz2,cl->GetLabel(0),cl->GetLabel(1),cl->GetLabel(2), chi2, track->IsFake() ? '-':'+'));
  //
  AddSeedBranch(track);
#ifdef  _FILL_CONTROL_HISTOS_
  if (htrPt>0) {
    ((TH2*)fCHistoArr->At(kHChi2Nrm+hcOffs))->Fill(htrPt,track->GetChi2GloNrm());
  }
#endif
  //
  return kClusterMatching;
}

//_________________________________________________________________________
Bool_t AliITSUTrackerGlo::NeedToKill(AliITSUSeed *seed, Int_t flag)
{
  // check if the seed should not be discarded
  const UShort_t kMask = 0xffff;
  if (flag==kMissingCluster) {
    int lastChecked = seed->GetLayerID();
    UShort_t patt = seed->GetHitsPattern();
    if (lastChecked) patt |= ~(kMask<<lastChecked); // not all layers were checked, complete unchecked ones by potential hits
    Bool_t seedOK = fCurrTrackCond->CheckPattern(patt);
    return !seedOK;
  }
  return kTRUE;
}

//______________________________________________________________________________
Bool_t AliITSUTrackerGlo::PropagateSeed(AliITSUSeed *seed, Double_t xToGo, Double_t mass, Double_t maxStep, Bool_t matCorr) 
{
  // propagate seed to given x applying material correction if requested
  const Double_t kEpsilon = 1e-5;
  Double_t xpos     = seed->GetX();
  Int_t dir         = (xpos<xToGo) ? 1:-1;
  Double_t xyz0[3],xyz1[3],param[7];
  //
  Bool_t updTime = dir>0 && seed->IsStartedTimeIntegral();
  if (matCorr || updTime) seed->GetXYZ(xyz1);   //starting global position
  while ( (xToGo-xpos)*dir > kEpsilon){
    Double_t step = dir*TMath::Min(TMath::Abs(xToGo-xpos), maxStep);
    Double_t x    = xpos+step;
    Double_t bz=GetBz();   // getting the local Bz
    if (!seed->PropagateToX(x,bz)) return kFALSE;
    double ds = 0;
    if (matCorr || updTime) {
      xyz0[0]=xyz1[0]; // global pos at the beginning of step
      xyz0[1]=xyz1[1];
      xyz0[2]=xyz1[2];
      seed->GetXYZ(xyz1);    //  // global pos at the end of step
      if (matCorr) {
	MeanMaterialBudget(xyz0,xyz1,param);	
	Double_t xrho=param[0]*param[4], xx0=param[1];
	if (dir>0) xrho = -xrho; // outward should be negative
	if (!seed->ApplyMaterialCorrection(xx0,xrho,mass,kFALSE)) {AliInfo("Fail2"); seed->Print("etp"); return kFALSE;}
	ds = param[4];
      }
       else { // matCorr is not requested but time integral is
	double d0 = xyz1[0]-xyz0[0];
	double d1 = xyz1[1]-xyz0[1];
	double d2 = xyz1[2]-xyz0[2];	
	ds = TMath::Sqrt(d0*d0+d1*d1+d2*d2);
      }     
    }
    if (updTime) seed->AddTimeStep(ds);
    xpos = seed->GetX();
  }
  return kTRUE;
}

//______________________________________________________________________________
Bool_t AliITSUTrackerGlo::PropagateSeed(AliExternalTrackParam *seed, Double_t xToGo, Double_t mass, Double_t maxStep, Bool_t matCorr) 
{
  // propagate seed to given x applying material correction if requested
  const Double_t kEpsilon = 1e-5;
  Double_t xpos     = seed->GetX();
  Int_t dir         = (xpos<xToGo) ? 1:-1;
  Double_t xyz0[3],xyz1[3],param[7];
  //
  if (AliDebugLevelClass()>1) {
    AliDebug(2,Form("Before Propagate to X=%f with M=%.3f MaxStep=%.4f MatCorr=%d",xToGo,mass,maxStep,matCorr));
    seed->AliExternalTrackParam::Print();
  }
  Bool_t updTime = dir>0 && seed->IsStartedTimeIntegral();
  if (matCorr || updTime) seed->GetXYZ(xyz1);   //starting global position
  while ( (xToGo-xpos)*dir > kEpsilon){
    Double_t step = dir*TMath::Min(TMath::Abs(xToGo-xpos), maxStep);
    Double_t x    = xpos+step;
    Double_t bz=GetBz();   // getting the local Bz
    if (!seed->PropagateTo(x,bz))  return kFALSE;
    double ds = 0;
    if (matCorr || updTime) {
      xyz0[0]=xyz1[0]; // global pos at the beginning of step
      xyz0[1]=xyz1[1];
      xyz0[2]=xyz1[2];
      seed->GetXYZ(xyz1);    //  // global pos at the end of step
      //
      if (matCorr) {
	MeanMaterialBudget(xyz0,xyz1,param);	
	Double_t xrho=param[0]*param[4], xx0=param[1];
	if (dir>0) xrho = -xrho; // outward should be negative
	if (!seed->CorrectForMeanMaterial(xx0,xrho,mass)) return kFALSE;
	ds = param[4];
      }
      else { // matCorr is not requested but time integral is
	double d0 = xyz1[0]-xyz0[0];
	double d1 = xyz1[1]-xyz0[1];
	double d2 = xyz1[2]-xyz0[2];	
	ds = TMath::Sqrt(d0*d0+d1*d1+d2*d2);
      }
    }
    if (updTime) seed->AddTimeStep(ds);
    //
    xpos = seed->GetX();
  }
  if (AliDebugLevelClass()>1) {
    AliDebug(2,Form("After Propagate to X=%f",xToGo));
    seed->AliExternalTrackParam::Print();
  }
  return kTRUE;
}

//______________________________________________________________________________
Bool_t AliITSUTrackerGlo::FinalizeHypothesis(AliITSUTrackHyp* hyp)
{
  // finalize single TPC track hypothesis
  if (!hyp || hyp->GetESDTrack()->IsOn(AliESDtrack::kITSin)) return kFALSE;
  AliITSUSeed* winner = 0;
  fCurrHyp = hyp;
  fCurrMass = hyp->GetMass();
  if (!(winner=hyp->DefineWinner())) return kFALSE;
  FlagSeedClusters(winner,kTRUE);
  CookMCLabel(hyp);
  //
#ifdef  _FILL_CONTROL_HISTOS_
  if (fCHistoArr) {
    TH2* hchimt = 0;
    TH2* hchiSA = 0;
    int lb = Abs(hyp->GetESDTrack()->GetTPCLabel());
    if ( hyp->GetITSLabel()==lb ) {
      hchimt = (TH2*)fCHistoArr->At(kHChiMatchCorr);
      hchiSA = (TH2*)fCHistoArr->At(kHChiITSSACorr);
    }
    else if ( Abs(hyp->GetITSLabel()) == lb ) hchimt = (TH2*)fCHistoArr->At(kHChiMatchFake);
    else if ( hyp->GetITSLabel()>=0 ) hchimt = (TH2*)fCHistoArr->At(kHChiMatchCorrMiss);
    else hchimt = (TH2*)fCHistoArr->At(kHChiMatchFakeMiss);
    if (!hchiSA) hchiSA =  (TH2*)fCHistoArr->At(kHChiITSSAFake);
    //    printf("MTStatus: ITS:%+5d TPC:%+5d chimt:%e chi2SA:%e-> %s\n",hyp->GetITSLabel(),lb,winner->GetChi2ITSTPC(),winner->GetChi2ITSSA(),hchimt->GetName());
    if (hchimt) hchimt->Fill(hyp->GetTPCSeed()->Pt(),winner->GetChi2ITSTPC());
    if (hchiSA) hchiSA->Fill(hyp->GetTPCSeed()->Pt(),winner->GetChi2ITSSA());      
  }
#endif    
  //
  UpdateESDTrack(hyp,AliESDtrack::kITSin);
  return kTRUE;
}

//______________________________________________________________________________
void AliITSUTrackerGlo::FinalizeHypotheses()
{
  // select winner for each hypothesis, remove cl. sharing conflicts
  AliCodeTimerAuto("",0); 
  AliDebug(2,"TODO");
  //
  int nh = fHypStore.GetEntriesFast();
  for (int ih=0;ih<nh;ih++) {
    if (FinalizeHypothesis( GetTrackHyp(ih) )) fCountITSin++;
  }
  //
  AliITSUSeed* winner = 0;

#ifdef  _FILL_CONTROL_HISTOS_
  // if requested, collect cluster sharing statistics
  TH2* hShare = 0;
  if (fCHistoArr && (hShare=(TH2*)fCHistoArr->At(kHClShare))) {
    for (int ih=0;ih<nh;ih++) {
      AliITSUTrackHyp* hyp = GetTrackHyp(ih);
      if (!hyp || !(winner=hyp->GetWinner())) continue;
      int lrID = 0;
      double pt = hyp->Pt();
      do {
	int clID = winner->GetLrCluster(lrID);
	if (clID<0) continue;
	AliITSUClusterPix* cl = (AliITSUClusterPix*)fITS->GetLayerActive(lrID)->GetCluster(clID);
	if (!cl->IsClusterShared()) continue;
	hShare->Fill(pt,winner->IsFake() ? lrID+fNLrActive : lrID);
      } while ((winner=(AliITSUSeed*)winner->GetParent()));
    }  
  }
#endif  

  AliRefArray** refArr = new AliRefArray*[fNLrActive];
  for (int ilr=0;ilr<fNLrActive;ilr++) refArr[ilr] = new AliRefArray(1000);
  for (int ih=0;ih<nh;ih++) {
    AliITSUTrackHyp* hyp = GetTrackHyp(ih);
    if (!hyp || !(winner=hyp->GetWinner())) continue;
    int lrID = 0;
    do {
      int clID = winner->GetLrCluster(lrID);
      if (clID<0) continue;
      AliITSUClusterPix* cl = (AliITSUClusterPix*)fITS->GetLayerActive(lrID)->GetCluster(clID);
      if (!cl->IsClusterShared()) continue;
      refArr[lrID]->AddReference(clID,ih);
    } while ((winner=(AliITSUSeed*)winner->GetParent()));
  }    
  //  /*
  UInt_t refs[100];
  for (int ilr=0;ilr<fNLrActive;ilr++) {
    int ncl = fITS->GetLayerActive(ilr)->GetNClusters();
    printf("\nClusterSharingDump: Lr %d (%d cl)\n",ilr,ncl);
    int cnt = 0;
    for (int icl=0;icl<ncl;icl++) {
      if (!refArr[ilr]->HasReference(icl)) continue;
      int nref = refArr[ilr]->GetReferences(icl,refs,100);
      printf("--- cl%3d(#%d): NShare=%4d\n",cnt++,icl,nref);     
      for (int ir=0;ir<nref;ir++) {
	AliITSUTrackHyp* hyp = GetTrackHyp(refs[ir]);
	winner = hyp->GetWinner();
	AliESDtrack* esdTr = hyp->GetESDTrack();
	printf("#%4d Pt:%.3f Chi:%6.2f Ncl:%d MCits%+5d MCtpc:%+5d ESD:%4d |",
	       refs[ir],winner->Pt(),winner->GetChi2GloNrm(),winner->GetNLayersHit(),
	       hyp->GetITSLabel(),esdTr->GetTPCLabel(),esdTr->GetID());
	int prevL=-1;
	do {
	  int lrs;
	  int clID = winner->GetLrCluster(lrs);
	  if (clID<0) continue;
	  while( lrs>++prevL ) printf("%4s        ","----");
	  printf("%4d (%5.1f)",clID,winner->GetChi2Cl());
	} while ((winner=(AliITSUSeed*)winner->GetParent()));
	printf("|\n");
      }
    }
  }
  //  */
  delete[] refArr;

}

//______________________________________________________________________________
void AliITSUTrackerGlo::UpdateESDTrack(AliITSUTrackHyp* hyp,Int_t flag)
{
  // update ESD track with current best hypothesis
  AliESDtrack* esdTr = hyp->GetESDTrack();
  if (!esdTr) return;
  AliITSUSeed* win = hyp->GetWinner();
  if (!win) return;
  double chiSav;
  //
  switch (flag) {
  case AliESDtrack::kITSin: 
    esdTr->UpdateTrackParams(hyp,flag); // update kinematics
    // TODO: set cluster info
    break;
    //
  case AliESDtrack::kITSout: 
    // here the stored chi2 will correspond to backward ITS-SA fit
    esdTr->UpdateTrackParams(hyp,flag); // update kinematics
    // TODO: avoid setting friend
    break;
    //
  case AliESDtrack::kITSrefit: 

    // at the moment fill as a chi2 the TPC-ITS matching chi2
    chiSav = hyp->GetChi2();
    hyp->SetChi2(win->GetChi2ITSTPC());
    esdTr->UpdateTrackParams(hyp,flag); // update kinematics
    hyp->SetChi2(chiSav);
    // TODO: avoid setting cluster info
    break;
  default:
    AliFatal(Form("Unknown flag %d",flag));
  }
  //
  esdTr->SetITSLabel(hyp->GetITSLabel());
  // transfer module indices
  // TODO
}

//______________________________________________________________________________
Double_t AliITSUTrackerGlo::RefitTrack(AliExternalTrackParam* trc, Double_t rDest, Int_t stopCond)
{
  // refit track till radius rDest. The cluster,mass info is taken from fCurrHyp (and its winner seed)
  // if stopCond<0 : propagate till last cluster then stop
  // if stopCond==0: propagate till last cluster then try to go till limiting rDest, don't mind if fail
  // if stopCond>0 : rDest must be reached
  //
  double rCurr = Sqrt(trc->GetX()*trc->GetX() + trc->GetY()*trc->GetY());
  int dir,lrStart,lrStop;
  //
  dir = rCurr<rDest ? 1 : -1;
  lrStart = fITS->FindFirstLayerID(rCurr,dir);
  lrStop  = fITS->FindLastLayerID(rDest,dir); // lr id before which we have to stop
  //
  if (AliDebugLevelClass()>2) {
    printf("Refit %d: Lr:%d (%f) -> Lr:%d (%f)\n",dir,lrStart,rCurr, lrStop,rDest);
    printf("Before refit: "); trc->Print();
  }
  if (lrStop<0 || lrStart<0) AliFatal(Form("Failed to find start(%d) or last(%d) layers. Track from %.3f to %.3f",lrStart,lrStop,rCurr,rDest));
  //
  Int_t clInfo[2*AliITSUAux::kMaxLayers];
  Int_t nCl = fCurrHyp->FetchClusterInfo(clInfo);
  fCurrMass = fCurrHyp->GetMass();
  AliExternalTrackParam tmpTr(*trc);
  double chi2 = 0;
  int iclLr[2],nclLr,clCount=0;
  //
  int lrStop1 = lrStop+1;
  for (int ilr=lrStart;ilr!=lrStop1;ilr+=dir) {
    AliITSURecoLayer* lr = fITS->GetLayer(ilr);
    if ( dir*(rCurr-lr->GetR(dir))>0) continue; // this layer is already passed
    int ilrA2,ilrA = lr->GetActiveID();
    // passive layer or active w/o hits will be traversed on the way to next cluster
    if (!lr->IsActive() || clInfo[ilrA2=(ilrA<<1)]<0) continue; 
    //
    // select the order in which possible 2 clusters (in case of the overlap) will be traversed and fitted
    nclLr=0;
    if (dir>0) { // clusters are stored in increasing radius order
      iclLr[nclLr++]=clInfo[ilrA2++];
      if (clInfo[ilrA2]>=0) iclLr[nclLr++]=clInfo[ilrA2];
    }
    else {
      if ( clInfo[ilrA2+1]>=0 ) iclLr[nclLr++]=clInfo[ilrA2+1];
      iclLr[nclLr++]=clInfo[ilrA2];
    }
    //
    Bool_t transportedToLayer = kFALSE;
    for (int icl=0;icl<nclLr;icl++) {
      AliITSUClusterPix* clus =  (AliITSUClusterPix*)lr->GetCluster(iclLr[icl]);
      AliITSURecoSens* sens = lr->GetSensorFromID(clus->GetVolumeId());
      if (!tmpTr.Rotate(sens->GetPhiTF())) {
	AliESDtrack* trESD = fCurrHyp->GetESDTrack();
	AliDebug(2,Form("Failed on rotate to %f | ESDtrack#%d (MClb:%d)",sens->GetPhiTF(),trESD->GetID(),trESD->GetTPCLabel()));
	return -1;
      }
      //
      double xClus = sens->GetXTF()+clus->GetX();
      if (!transportedToLayer) {
	if (ilr!=lrStart && !TransportToLayerX(&tmpTr,lrStart,ilr,xClus)) {
	  AliESDtrack* trESD = fCurrHyp->GetESDTrack();
	  AliDebug(2,Form("Failed to transport %d -> %d | ESDtrack#%d (MClb:%d)\n",lrStart,ilr,trESD->GetID(),trESD->GetTPCLabel()));
	  return -1; // go to the entrance to the layer
	}
	lrStart = ilr;
	transportedToLayer = kTRUE;
      }
      //
      if (AliDebugLevelClass()>1) {
	AliDebug(2,Form("Propagate to cl:%d on lr %d Need to go %.4f -> %.4f",icl,ilrA,tmpTr.GetX(),xClus));
      }
      //
      if (!PropagateSeed(&tmpTr,xClus,fCurrMass)) {
	AliESDtrack* trESD = fCurrHyp->GetESDTrack();
	AliDebug(2,Form("Failed on propagate to %f (dir=%d) | ESDtrack#%d (MClb:%d)",xClus,dir,trESD->GetID(),trESD->GetTPCLabel()));
	return -1;
      }
      //
      Double_t p[2]={clus->GetY(), clus->GetZ()};
      Double_t cov[3]={clus->GetSigmaY2(), clus->GetSigmaYZ(), clus->GetSigmaZ2()};
      double chi2cl = tmpTr.GetPredictedChi2(p,cov);
      chi2 += chi2cl;
      //
#ifdef  _FILL_CONTROL_HISTOS_
      int hcOffs = (1+fTrackPhase)*kHistosPhase + ilrA;
      double htrPt=-1;
      if (fCHistoArr && fTrackPhase>kClus2Tracks && trc->GetLabel()>=0/* && trc->Charge()>0*/) {
	htrPt = tmpTr.Pt();
	double dy = p[0]-tmpTr.GetY();
	double dz = p[1]-tmpTr.GetZ();
	((TH2*)fCHistoArr->At(kHResY+hcOffs))->Fill(htrPt,dy);
	((TH2*)fCHistoArr->At(kHResZ+hcOffs))->Fill(htrPt,dz);
	double errY = tmpTr.GetSigmaY2();
	double errZ = tmpTr.GetSigmaZ2();
	if (errY>0) ((TH2*)fCHistoArr->At(kHResYP+hcOffs))->Fill(htrPt,dy/Sqrt(errY));
	if (errZ>0) ((TH2*)fCHistoArr->At(kHResZP+hcOffs))->Fill(htrPt,dz/Sqrt(errZ));
	((TH2*)fCHistoArr->At(kHChi2Cl+hcOffs))->Fill(htrPt,chi2cl);
      }
#endif  
      //      
      if ( !tmpTr.Update(p,cov) ) {
	AliESDtrack* trESD = fCurrHyp->GetESDTrack();
	AliDebug(2,Form("Failed on Update | ESDtrack#%d (MClb:%d)",trESD->GetID(),trESD->GetTPCLabel()));
	return -1;
      }
      if (AliDebugLevelClass()>1) {
	printf("AfterRefit: "); tmpTr.Print();
      }
      if (++clCount==nCl && stopCond<0) {
	*trc = tmpTr;
	return chi2; // it was requested to not propagate after last update
      }
    }
    //
  }
  // All clusters were succesfully fitted. Even if the track does not reach rDest, this is enough to validate it.
  // Still, try to go as close as possible to rDest.
  //
  if (lrStart!=lrStop) {
    if (!TransportToLayer(&tmpTr,lrStart,lrStop)) {
      AliDebug(-1,Form("Failed on TransportToLayer %d->%d | ESDtrack#%d (MClb:%d), X=%f",lrStart,lrStop,fCurrESDtrack->GetID(),fCurrESDtrMClb,tmpTr.GetX()));
      if (stopCond>0) return -chi2; // rDest was obligatory
    }    
    if (!GoToExitFromLayer(&tmpTr,fITS->GetLayer(lrStop),dir)) {
      AliDebug(-1,Form("Failed on GoToExitFromLayer %d | ESDtrack#%d (MClb:%d), X=%f",lrStop,fCurrESDtrack->GetID(),fCurrESDtrMClb,tmpTr.GetX()));
      if (stopCond>0) return -chi2; // rDest was obligatory
    }
  }
  // go to the destination radius. Note that here we don't select direction to avoid precision problems
  if (!tmpTr.GetXatLabR(rDest,rDest,GetBz(),0) || !PropagateSeed(&tmpTr,rDest,fCurrMass, 100, kFALSE)) {
    if (stopCond>0) return -chi2; // rDest was obligatory
  }
  *trc=tmpTr;
  if (AliDebugLevelClass()>2) {
    printf("After refit (now at lr %d): ",lrStop); trc->Print();
  }
  return chi2;
}

//__________________________________________________________________
void AliITSUTrackerGlo::CookMCLabel(AliITSUTrackHyp* hyp) 
{
  // build MC label
  //
  const int kMaxLbPerCl = 3;
  int lbID[kMaxLayers*6],lbStat[kMaxLayers*6];
  Int_t lr,nLab=0,nCl=0;
  AliITSUSeed *seed = hyp->GetWinner();
  while(seed) {
    int clID = seed->GetLrCluster(lr);
    if (clID>=0) {
      AliCluster *cl = fITS->GetLayerActive(lr)->GetCluster(clID);
      nCl++;
      for (int imc=0;imc<kMaxLbPerCl;imc++) { // labels within single cluster
	int trLb = cl->GetLabel(imc);
	if (trLb<0) break;
	// search this mc track in already accounted ones
	int iLab;
	for (iLab=0;iLab<nLab;iLab++) if (lbID[iLab]==trLb) break;
	if (iLab<nLab) lbStat[iLab]++;
	else {
	  lbID[nLab] = trLb;
	  lbStat[nLab++] = 1;
	}
      } // loop over given cluster's labels
    }
    seed = (AliITSUSeed*)seed->GetParent();
  } // loop over clusters
  // 
  AliESDtrack* esdTr = hyp->GetESDTrack();
  int tpcLab = esdTr ? Abs(esdTr->GetTPCLabel()) : -kDummyLabel;
  if (nCl && nLab) {
    int maxLab=0,nTPCok=0;
    for (int ilb=nLab;ilb--;) {
      int st = lbStat[ilb];
      if (lbStat[maxLab]<st) maxLab=ilb;
      if (tpcLab==lbID[ilb]) nTPCok += st;
    }
    hyp->SetFakeRatio(1.-float(nTPCok)/nCl);
    hyp->SetLabel( nTPCok==nCl ? tpcLab : -tpcLab);
    hyp->SetITSLabel( lbStat[maxLab]==nCl ? lbID[maxLab] : -lbID[maxLab]); // winner label
    return;
  }
  //
  hyp->SetFakeRatio(-1.);
  hyp->SetLabel( -tpcLab );
  hyp->SetITSLabel( kDummyLabel );
}

//__________________________________________________________________
Bool_t AliITSUTrackerGlo::AddSeedBranch(AliITSUSeed* seed)
{
  // add new prolongation branch for the seed to temporary array. The seeds are sorted according to Compare f-n
  if (fNCandidatesAdded+fNBranchesAdded>=fLayerMaxCandidates ) {
    AliInfo(Form("Number of candidates at layer %d for current seed reached %d, increasing buffer",fCurrActLrID,fLayerMaxCandidates));
    fLayerMaxCandidates = 2*(fLayerMaxCandidates+1);
    AliITSUSeed** tmpArr = fLayerCandidates;
    fLayerCandidates = new AliITSUSeed*[fLayerMaxCandidates];
    memcpy(fLayerCandidates,tmpArr,(fNCandidatesAdded+fNBranchesAdded)*sizeof(AliITSUSeed*));
    delete tmpArr; // delete only array, not objects
  }
  AliITSUSeed** branches = &fLayerCandidates[fNCandidatesAdded]; // note: fNCandidatesAdded is incremented after adding all branches of current seed
  int slot=fNBranchesAdded++;
  for (int slotF=slot;slotF--;) { // slotF is always slot-1
    AliITSUSeed* si = branches[slotF];
    if (si->Compare(seed)<0) break; // found the last seed with better quality
    // otherwise, shift the worse seed to the next slot
    branches[slot] = si;
    slot = slotF; // slot should be slotF+1
  }
  // if needed, move worse seeds
  branches[slot] = seed;
  return kTRUE;
  //
}

//__________________________________________________________________
void AliITSUTrackerGlo::ValidateAllowedBranches(Int_t acceptMax)
{
  // keep allowed number of branches for current seed and disable extras
  AliCodeTimerAuto("",0); 
  int nb = Min(fNBranchesAdded,acceptMax);
  //  if (nb<fNBranchesAdded) printf("ValidateAllowedBranches: %d of %d (%d) on lr %d\n",nb,fNBranchesAdded,fNCandidatesAdded,ilr);
  // disable unused branches
  AliITSUSeed** branches = &fLayerCandidates[fNCandidatesAdded];
#ifdef  _FILL_CONTROL_HISTOS_
  int bestID = -1;
  for (int ib=0;ib<fNBranchesAdded;ib++) {
    AliITSUSeed* sd = branches[ib];
    if (!sd->ContainsFake() && (bestID<0 || sd->Compare(branches[bestID])<0) ) bestID = ib;
  }
  if (bestID>=0) {
    TH2* hb = (TH2*)fCHistoArr->At(kHBestInBranch + (1+fTrackPhase)*kHistosPhase + fCurrActLrID);
    if (hb) hb->Fill(branches[bestID]->Pt(), bestID);
  }
#endif
  //
  for (int ib=nb;ib<fNBranchesAdded;ib++) {
    //
#ifdef  _FILL_CONTROL_HISTOS_    
    if (AliDebugLevelClass()>-2 && !branches[ib]->ContainsFake() /*&& branches[ib]->GetNLayersHit()*/
	&& (bestID<0 || branches[ib]->Compare(branches[bestID])<0 ) ) {
      printf("Suppress good branch as %d of %d |",ib,fNBranchesAdded); branches[ib]->Print();
      //      printf("Survivors : \n");
      //      for (int j=0;j<nb;j++) branches[j]->Print();
    }
#endif    
    MarkSeedFree(branches[ib]);
  }
  fNCandidatesAdded += nb; // update total candidates counter
  fNBranchesAdded = 0; // reset branches counter
  //
}

//__________________________________________________________________
void AliITSUTrackerGlo::ValidateAllowedCandidates(Int_t ilr, Int_t acceptMax)
{
  // transfer allowed number of branches to hypothesis container
  //
  AliCodeTimerAuto("",0); 
  // sort candidates in increasing order of chi2
  static int lastSize = 0;
  static int *index = 0;
  static float *chi2 = 0;
  if (fLayerMaxCandidates>lastSize) {
    lastSize = fLayerMaxCandidates;
    delete[] index;
    delete[] chi2;
    index = new int[lastSize];
    chi2  = new float[lastSize];
  }
  for (int i=fNCandidatesAdded;i--;) chi2[i] = fLayerCandidates[i]->GetChi2GloNrm();
  Sort(fNCandidatesAdded,chi2,index,kFALSE);
  //
#ifdef  _FILL_CONTROL_HISTOS_
  int bestID = -1;
  for (int ib=0;ib<fNCandidatesAdded;ib++) {
    AliITSUSeed* sd = fLayerCandidates[index[ib]];
    if (!sd->ContainsFake() && (bestID<0 || sd->Compare(fLayerCandidates[index[bestID]])<0) ) bestID = ib;
  }
  if (bestID>=0) {
    TH2* hb = (TH2*)fCHistoArr->At(kHBestInCand + (1+fTrackPhase)*kHistosPhase + fCurrActLrID);
    if (hb) hb->Fill(fLayerCandidates[index[bestID]]->Pt(), bestID);
  }
#endif
  //
  int nacc=0,nb=0;
  if (ilr>0) { // just take 1st acceptMax candidates
    nb = Min(fNCandidatesAdded,acceptMax);
    for (int ib=0;ib<nb;ib++) AddProlongationHypothesis(fLayerCandidates[index[ib]],ilr);
  }
  else { // for innermost layer test ITS SA backward chi2 and matching to TPC
    AliITSUSeed* wn0 = fCurrHyp->GetWinner(); // in principle, should be NULL
    for (nb=0;nb<fNCandidatesAdded;nb++) {
      AliITSUSeed* sd = fLayerCandidates[index[nb]];    
      fCurrHyp->SetWinner(sd);
      if (!CheckBackwardMatching(sd)) MarkSeedFree(sd); // discard bad backward tracks
      else {
	AddProlongationHypothesis(sd,ilr);
	if (++nacc==acceptMax) {nb++; break;} // the rest will be discarded
      }
    }
    fCurrHyp->SetWinner(wn0); // restore original winner (NULL?)
  }
  //
  // disable unused candidates
  for (int ib=nb;ib<fNCandidatesAdded;ib++) {
    //
#ifdef  _FILL_CONTROL_HISTOS_
    if (AliDebugLevelClass()>-2 && !fLayerCandidates[index[ib]]->ContainsFake() /*&& fLayerCandidates[index[ib]]->GetNLayersHit()*/
	&& (bestID<0 || fLayerCandidates[index[ib]]->Compare(fLayerCandidates[index[bestID]])<0 ) ) {
      printf("Suppress good candidate as %d of %d |",index[ib],fNCandidatesAdded); fLayerCandidates[index[ib]]->Print();
    }
#endif
    MarkSeedFree(fLayerCandidates[index[ib]]);    
  }
  fNCandidatesAdded = 0; // reset candidates counter
  //
}

//__________________________________________________________________
Bool_t AliITSUTrackerGlo::CheckBackwardMatching(AliITSUSeed* seed)
{
  // check seed backward propagation chi2 and matching to TPC 
  double bz0 = GetBz();
  double rDest = fITS->GetRITSTPCRef(); // reference radius for comparison
  static AliExternalTrackParam trback;
  trback = *seed;
  trback.ResetCovariance(10000);
  int ndf = seed->GetNLayersHit()*2-5;
  double chi2sa = RefitTrack(&trback,rDest,1);
  if (chi2sa<0) return kFALSE;
  if (ndf>0) chi2sa /= ndf;
  if (chi2sa>fCurrTrackCond->GetMaxITSSAChi2()) return kFALSE;
  //
  // relate to TPC track at outer layer
  AliExternalTrackParam* tpcSeed = fCurrHyp->GetTPCSeed();
  if (!trback.Rotate(tpcSeed->GetAlpha()) || !trback.PropagateParamOnlyTo(tpcSeed->GetX(),bz0)) {
    if (AliDebugLevelClass()>+1 && !seed->ContainsFake()) {
      AliInfo(Form("Failed to propagate seed to TPC track @ X:%.3f Alpha:%.3f",tpcSeed->GetX(),tpcSeed->GetAlpha()));
      seed->Print("etp");
      trback.Print();
    }
    return kFALSE; 
  }
  double chi2Match = trback.GetPredictedChi2(tpcSeed)/5;
  if (chi2Match>fCurrTrackCond->GetMaxITSTPCMatchChi2()) return kFALSE;
  //
  seed->SetChi2ITSSA(chi2sa);
  seed->SetChi2ITSTPC(chi2Match);
  return kTRUE;
}

//__________________________________________________________________
void AliITSUTrackerGlo::SaveReducedHypothesesTree(AliITSUTrackHyp* dest)
{
  // remove those hypothesis seeds which dont lead to candidates at final layer
  //
  // 1st, flag the seeds to save
  int lr0 = 0;
  for (int isd=0;isd<fCurrHyp->GetNSeeds(lr0);isd++) {
    AliITSUSeed* seed = fCurrHyp->RemoveSeed(lr0,isd);
    if (!seed) continue;
    seed->FlagTree(AliITSUSeed::kSave);
    dest->AddSeed(seed,lr0);
  }
  for (int ilr=1;ilr<fNLrActive;ilr++) {
    int nsd = fCurrHyp->GetNSeeds(ilr);
    for (int isd=0;isd<nsd;isd++) {
      AliITSUSeed* seed = fCurrHyp->RemoveSeed(ilr,isd);
      if (!seed) continue; // already discarded or saved
      if (seed->IsSaved()) dest->AddSeed(seed,ilr);
      else MarkSeedFree(seed);
    }
  }
  //
  //  AliInfo(Form("SeedsPool: %d, BookedUpTo: %d, free: %d",fSeedsPool.GetSize(),fSeedsPool.GetEntriesFast(),fNFreeSeeds));
}

//__________________________________________________________________
void AliITSUTrackerGlo::FlagSplitClusters()
{
  // set special bit on split clusters using MC info
  for (int ilr=fNLrActive;ilr--;) {
    int nsplit=0;
    AliITSURecoLayer* lr = fITS->GetLayerActive(ilr);
    for (int isn=lr->GetNSensors();isn--;) {
      AliITSURecoSens* sens = lr->GetSensor(isn);
      int nCl = sens->GetNClusters();
      if (!nCl) continue;
      int cl0 = sens->GetFirstClusterId();
      for (int icl=nCl;icl--;) {
	AliITSUClusterPix *cl = (AliITSUClusterPix*)lr->GetCluster(cl0+icl);
	for (int icl1=icl;icl1--;) {
	  AliITSUClusterPix *cl1 = (AliITSUClusterPix*)lr->GetCluster(cl0+icl1);
	  if (cl->HasCommonTrack(cl1)) {
	    if (!cl->IsSplit())  nsplit++;
	    if (!cl1->IsSplit()) nsplit++;
	    cl->SetSplit();
	    cl1->SetSplit();
	  }
	}
      }
    }
    AliInfo(Form("%4d out of %4d clusters are split",nsplit,lr->GetNClusters()));
  }
  //
}

//__________________________________________________________________
Bool_t AliITSUTrackerGlo::ContainsSplitCluster(const AliITSUSeed* seed, Int_t maxSize)
{
  // check if the seed contains split cluster with size < maxSize
  int lrID,clID;
  if ( (clID=seed->GetLrCluster(lrID))>=0 ) {
    AliITSUClusterPix* cl = (AliITSUClusterPix*)fITS->GetLayerActive(lrID)->GetCluster(clID);
    if (cl->IsSplit() && cl->GetNPix()<maxSize ) return kTRUE;
  }
  return seed->GetParent() ? ContainsSplitCluster((AliITSUSeed*)seed->GetParent(),maxSize) : kFALSE;
  //
}

//__________________________________________________________________
void AliITSUTrackerGlo::PrintSeedClusters(const AliITSUSeed* seed, Option_t* option)
{
  // print seeds clusters
  int lrID,clID;
  if ( (clID=seed->GetLrCluster(lrID))>=0 ) {
    AliITSUClusterPix* cl = (AliITSUClusterPix*)fITS->GetLayerActive(lrID)->GetCluster(clID);
    cl->Print(option);
  }
  if (seed->GetParent()) PrintSeedClusters((AliITSUSeed*)seed->GetParent(), option);
  //
}

//__________________________________________________________________
void AliITSUTrackerGlo::FlagSeedClusters(const AliITSUSeed* seed, Bool_t flg)
{
  // mark used clusters
  int lrID,clID;
  while (seed) {
    if ( (clID=seed->GetLrCluster(lrID))>=0 ) ((AliITSUClusterPix*)fITS->GetLayerActive(lrID)->GetCluster(clID))->ModClUsage(flg);
    seed = (AliITSUSeed*)seed->GetParent();
  }
  //
}


#ifdef  _FILL_CONTROL_HISTOS_
//__________________________________________________________________
void AliITSUTrackerGlo::BookControlHistos()
{
  // book special control histos
  if (fCHistoArr) return;
  const int kNResDef=7;
  const double kResDef[kNResDef]={0.05,0.05,0.3, 0.05,1,0.5,1.5};
  fCHistoArr = new TObjArray();
  fCHistoArr->SetOwner(kTRUE);
  const double ptMax=10;
  const double plMax=10;
  const double chiMax=100;
  const int nptbins=50;
  const int nresbins=400;
  const int nplbins=50;
  const int nchbins=200;
  const int maxBr  = 15;
  const int maxCand = 200;
  TString ttl;
  for (int stp=0;stp<kNTrackingPhases;stp++) {
    for (int ilr=0;ilr<fNLrActive;ilr++) {
      int hoffs = (1+stp)*kHistosPhase + ilr;
      double mxdf = ilr>=kNResDef ? kResDef[kNResDef-1] : kResDef[ilr];
      ttl = Form("S%d_residY%d",stp,ilr);
      TH2F* hdy = new TH2F(ttl.Data(),ttl.Data(),nptbins,0,ptMax,nresbins,-mxdf,mxdf);
      fCHistoArr->AddAtAndExpand(hdy,hoffs + kHResY);
      hdy->SetDirectory(0);
      //
      ttl = Form("S%d_residYPull%d",stp,ilr);	
      TH2F* hdyp = new TH2F(ttl.Data(),ttl.Data(),nptbins,0,ptMax,nplbins,-plMax,plMax);
      fCHistoArr->AddAtAndExpand(hdyp,hoffs + kHResYP);
      hdyp->SetDirectory(0);
      //
      ttl = Form("S%d_residZ%d",stp,ilr);	
      TH2F* hdz = new TH2F(ttl.Data(),ttl.Data(),nptbins,0,ptMax,nresbins,-mxdf,mxdf);
      fCHistoArr->AddAtAndExpand(hdz,hoffs + kHResZ);
      hdz->SetDirectory(0);
      //
      ttl = Form("S%d_residZPull%d",stp,ilr);		
      TH2F* hdzp = new TH2F(ttl.Data(),ttl.Data(),nptbins,0,ptMax,nplbins,-plMax,plMax);
      hdzp->SetDirectory(0);
      fCHistoArr->AddAtAndExpand(hdzp,hoffs + kHResZP);
      //
      ttl = Form("S%d_chi2Cl%d",stp,ilr);		
      TH2F* hchi = new TH2F(ttl.Data(),ttl.Data(),nptbins,0,ptMax, nchbins,0.,chiMax);
      hchi->SetDirectory(0);
      fCHistoArr->AddAtAndExpand(hchi,hoffs + kHChi2Cl);
      //
      ttl = Form("S%d_chi2Nrm%d",stp,ilr);		
      TH2F* hchiN = new TH2F(ttl.Data(),ttl.Data(),nptbins,0,ptMax, nchbins,0.,chiMax);
      hchiN->SetDirectory(0);
      fCHistoArr->AddAtAndExpand(hchiN,hoffs + kHChi2Nrm);
      //
      if (stp==0) { // these histos make sense only for clusters2tracks stage
	ttl = Form("S%d_bestInBranch%d",stp,ilr);		
	TH2* hnbr = new TH2F(ttl.Data(),ttl.Data(),nptbins,0,ptMax, maxBr,-0.5,maxBr-0.5);
	hnbr->SetDirectory(0);
	fCHistoArr->AddAtAndExpand(hnbr,hoffs + kHBestInBranch);
	//
	ttl = Form("S%d_bestInCands%d",stp,ilr);		
	TH2* hncn = new TH2F(ttl.Data(),ttl.Data(),nptbins,0,ptMax, maxCand,-0.5,maxCand-0.5);
	hncn->SetDirectory(0);
	fCHistoArr->AddAtAndExpand(hncn,hoffs + kHBestInCand);
	//
      }
    }
  }
  // custom histos
  ttl = Form("ClSharing");
  TH2* hclShare = new TH2F(ttl.Data(),ttl.Data(),nptbins,0,ptMax, 2*fNLrActive,0,2*fNLrActive);
  hclShare->SetDirectory(0);
  fCHistoArr->AddAtAndExpand(hclShare,kHClShare);
  //  
  TH2* hchiMatch = 0; 
  ttl = Form("Chi2MatchCorr");
  hchiMatch = new TH2F(ttl.Data(),ttl.Data(),nptbins,0,ptMax, nchbins,0.,chiMax);
  hchiMatch->SetDirectory(0);
  fCHistoArr->AddAtAndExpand(hchiMatch,kHChiMatchCorr);
  // 
  ttl = Form("Chi2MatchFake");
  hchiMatch = new TH2F(ttl.Data(),ttl.Data(),nptbins,0,ptMax, nchbins,0.,chiMax);
  hchiMatch->SetDirectory(0);
  fCHistoArr->AddAtAndExpand(hchiMatch,kHChiMatchFake);
  // 
  ttl = Form("Chi2MatchCorrMiss");
  hchiMatch = new TH2F(ttl.Data(),ttl.Data(),nptbins,0,ptMax, nchbins,0.,chiMax);
  hchiMatch->SetDirectory(0);
  fCHistoArr->AddAtAndExpand(hchiMatch,kHChiMatchCorrMiss);
  // 
  ttl = Form("Chi2MatchFakeMiss");
  hchiMatch = new TH2F(ttl.Data(),ttl.Data(),nptbins,0,ptMax, nchbins,0.,chiMax);
  hchiMatch->SetDirectory(0);
  fCHistoArr->AddAtAndExpand(hchiMatch,kHChiMatchFakeMiss);
  // 
  TH2* hchiSA = 0; 
  ttl = Form("Chi2ITSSACorr");
  hchiSA = new TH2F(ttl.Data(),ttl.Data(),nptbins,0,ptMax, nchbins/2,0.,chiMax/2);
  hchiSA->SetDirectory(0);
  fCHistoArr->AddAtAndExpand(hchiSA,kHChiITSSACorr);
  // 
  ttl = Form("Chi2ITSSAFake");
  hchiSA = new TH2F(ttl.Data(),ttl.Data(),nptbins,0,ptMax, nchbins/2,0.,chiMax/2);
  hchiSA->SetDirectory(0);
  fCHistoArr->AddAtAndExpand(hchiSA,kHChiITSSAFake);
  // 

}
#endif