/** CbmMuchFindVectors.cxx
 *@author A.Zinchenko <Alexander.Zinchenko@jinr.ru>
 *@since 2014
 **/
#include "CbmMuchFindVectors.h"
#include "CbmMuchDigiMatch.h"
#include "CbmMuchFindHitsStraws.h"
#include "CbmMuchModule.h"
#include "CbmMuchPoint.h"
#include "CbmMuchStation.h"
#include "CbmMuchStrawHit.h"
#include "CbmMuchTrack.h"

#include "FairRootManager.h"
#include "FairRunAna.h"
#include "FairRuntimeDb.h"

#include <TClonesArray.h>
#include <TMath.h>
#include <TMatrixD.h>
#include <TVectorD.h>

#include <iostream>

// -----   Default constructor   -------------------------------------------
CbmMuchFindVectors::CbmMuchFindVectors()
  : FairTask(),
    fGeoScheme(CbmMuchGeoScheme::Instance()),
    fTrackArray(NULL),
    fNofTracks(0),
    fHits(NULL),
    fPoints(NULL),
    fDigiMatches(NULL),
    fStatFirst(-1),
    fErrU(-1.0),
    fDiam(0.0),
    fCutChi2(20.0),
    fMinHits(10)
{
}
// -------------------------------------------------------------------------

// -----   Standard constructor   ------------------------------------------
CbmMuchFindVectors::CbmMuchFindVectors(
		const char* name,
		const char* title)
  : FairTask(name),
    fGeoScheme(CbmMuchGeoScheme::Instance()),
    fTrackArray(NULL),
    fNofTracks(0),
    fHits(NULL),
    fPoints(NULL),
    fDigiMatches(NULL),
    fStatFirst(-1),
    fErrU(-1.0),
    fDiam(0.0),
    fCutChi2(20.0),
    fMinHits(10)
{
}
// -------------------------------------------------------------------------

// -----   Destructor   ----------------------------------------------------
CbmMuchFindVectors::~CbmMuchFindVectors()
{
  fTrackArray->Delete();
  for (Int_t i = 0; i < fgkStat; ++i) {
    Int_t nVecs = fVectors[i].size();
    for (Int_t j = 0; j < nVecs; ++j) delete fVectors[i][j];
    //nVecs = fVectorsHigh[i].size();
    //for (Int_t j = 0; j < nVecs; ++j) delete fVectorsHigh[i][j];
  }
  for (map<Int_t,TDecompLU*>::iterator it = fLus.begin(); it != fLus.end(); ++it)
    delete it->second;
}
// -------------------------------------------------------------------------

// -----   Public method Init (abstract in base class)  --------------------
InitStatus CbmMuchFindVectors::Init()
{

  // Get and check FairRootManager
  FairRootManager* ioman = FairRootManager::Instance();
  if (ioman == NULL) Fatal("CbmMuchFindTracks::Init", "RootManager not instantiated!");

  // Create and register MuchTrack array
  fTrackArray = new TClonesArray("CbmMuchTrack",100);
  ioman->Register("MuchVector", "Much", fTrackArray, IsOutputBranchPersistent("MuchVector"));

  CbmMuchFindHitsStraws *hitFinder = (CbmMuchFindHitsStraws*) 
    FairRun::Instance()->GetTask("CbmMuchFindHitsStraws");
  if (hitFinder == NULL) Fatal("CbmMuchFindTracks::Init", "CbmMuchFindHitsStraws not run!");
  fDiam = hitFinder->GetDiam(0);

  fHits = static_cast<TClonesArray*> (ioman->GetObject("MuchStrawHit"));
  fPoints = static_cast<TClonesArray*> (ioman->GetObject("MuchPoint"));
  fDigiMatches = static_cast<TClonesArray*> (ioman->GetObject("MuchStrawDigiMatch"));

  // Find first straw station and get some geo constants
  Int_t nSt = fGeoScheme->GetNStations();
  for (Int_t i = 0; i < nSt; ++i) {
    CbmMuchStation* st = fGeoScheme->GetStation(i);
    CbmMuchModule* mod = fGeoScheme->GetModule(i, 0, 0, 0);
    if (mod->GetDetectorType() == 2) { 
      if (fStatFirst < 0) fStatFirst = CbmMuchAddress::GetStationIndex(st->GetDetectorId()); 
      //cout << " First station: " << fStatFirst << endl;
      Int_t nLays = st->GetNLayers();
      fRmin[i-fStatFirst] = st->GetRmin();
      fRmax[i-fStatFirst] = st->GetRmax();
      for (Int_t lay = 0; lay < nLays; ++lay) {
	CbmMuchLayer* layer = st->GetLayer(lay);
	Double_t phi = hitFinder->GetPhi(lay);
	for (Int_t iside = 0; iside < 2; ++iside) {
	  CbmMuchLayerSide* side = layer->GetSide(iside);
	  Int_t plane = lay * 2 + iside;
	  fDz[plane] = side->GetZ();
	  fCosa[plane] = TMath::Cos(phi);
	  fSina[plane] = TMath::Sin(phi);
	  if (plane == 0) fZ0[i-fStatFirst] = side->GetZ();
	  if (lay) {
	    fDtubes[i-fStatFirst][lay-1] = 
	      fRmax[i-fStatFirst] * TMath::Tan (TMath::ASin(fSina[plane]) - TMath::ASin(fSina[plane-2]));
	    fDtubes[i-fStatFirst][lay-1] = TMath::Abs(fDtubes[i-fStatFirst][lay-1]) / fDiam + 10;
	  }
	}
      }
    }
  }
  for (Int_t i = fgkPlanes - 1; i >= 0; --i) {
    fDz[i] -= fDz[0];
    //cout << fDz[i] << " ";
  }
  //cout << endl;
  ComputeMatrix(); // compute system matrices

  return kSUCCESS;
}
// -------------------------------------------------------------------------

// -----  SetParContainers -------------------------------------------------
void CbmMuchFindVectors::SetParContainers()
{
    FairRunAna* ana = FairRunAna::Instance();
    FairRuntimeDb* rtdb = ana->GetRuntimeDb();

    rtdb->getContainer("FairBaseParSet");
    rtdb->getContainer("CbmGeoPassivePar");
    //rtdb->getContainer("CbmGeoStsPar");
    //rtdb->getContainer("CbmGeoRichPar");
    rtdb->getContainer("CbmGeoMuchPar");
    //rtdb->getContainer("CbmGeoTrdPar");
    rtdb->getContainer("CbmFieldPar");
}
// -------------------------------------------------------------------------

// -----   Public method Exec   --------------------------------------------
void CbmMuchFindVectors::Exec(
		Option_t* opt)
{

  fTrackArray->Delete();
  for (Int_t i = 0; i < fgkStat; ++i) {
    Int_t nVecs = fVectors[i].size();
    for (Int_t j = 0; j < nVecs; ++j) delete fVectors[i][j];
    fVectors[i].clear();
    //nVecs = fVectorsHigh[i].size();
    //for (Int_t j = 0; j < nVecs; ++j) delete fVectorsHigh[i][j];
    fVectorsHigh[i].clear();
  }

  // Do all processing

  // Get hits
  GetHits();

  // Build vectors
  MakeVectors();

  // Remove vectors with wrong orientation
  // (using empirical cuts for omega muons at 8 GeV) 
  CheckParams();

  // Go to the high resolution mode processing
  Double_t err = fErrU;
  fErrU = 0.02;
  if (fErrU < 0.1) HighRes();
  fErrU = err;

  // Remove clones
  RemoveClones();

  // Remove short tracks
  RemoveShorts();

  // Store vectors
  StoreVectors();
}
// -------------------------------------------------------------------------

// -----   Public method Finish   ------------------------------------------
void CbmMuchFindVectors::Finish()
{
  fTrackArray->Clear();
  for (Int_t i = 0; i < fgkStat; ++i) {
    Int_t nVecs = fVectors[i].size();
    for (Int_t j = 0; j < nVecs; ++j) delete fVectors[i][j];
    //nVecs = fVectorsHigh[i].size();
    //for (Int_t j = 0; j < nVecs; ++j) delete fVectorsHigh[i][j];
  }
  for (map<Int_t,TDecompLU*>::iterator it = fLus.begin(); it != fLus.end(); ++it)
    delete it->second;
}
// -------------------------------------------------------------------------

// -----   Private method ComputeMatrix   ----------------------------------
void CbmMuchFindVectors::ComputeMatrix()
{
  // Compute system matrices for different hit plane patterns

  Double_t cos2[fgkPlanes], sin2[fgkPlanes], sincos[fgkPlanes], dz2[fgkPlanes];
  Bool_t onoff[fgkPlanes];

  for (Int_t i = 0; i < fgkPlanes; ++i) {
    cos2[i] = fCosa[i] * fCosa[i];
    sin2[i] = fSina[i] * fSina[i];
    sincos[i] = fSina[i] * fCosa[i];
    dz2[i] = fDz[i] * fDz[i];
    onoff[i] = kTRUE;
  }

  TMatrixD coef(4,4);
  Int_t  pattMax = 1 << fgkPlanes, nDouble = 0, nTot = 0;
    
  // Loop over doublet patterns
  for (Int_t ipat = 1; ipat < pattMax; ++ipat) {

    // Check if the pattern is valid:
    // either all doublets are active or 3 the first ones (for high resolution mode)
    nDouble = 0;
    for (Int_t j = 0; j < fgkPlanes; j += 2) if (ipat & (3 << j)) ++nDouble; else break;
    if ((ipat & (3 << 6)) == 0) ++nDouble; // 3 doublets
    if (nDouble < fgkPlanes / 2) continue;
    ++nTot;

    for (Int_t j = 0; j < fgkPlanes; ++j) onoff[j] = (ipat & (1 << j));

    coef = 0.0;
    for (Int_t i = 0; i < fgkPlanes; ++i) {
      if (!onoff[i]) continue;
      coef(0,0) += cos2[i];
      coef(0,1) += sincos[i];
      coef(0,2) += fDz[i] * cos2[i];
      coef(0,3) += fDz[i] * sincos[i];
    }
    for (Int_t i = 0; i < fgkPlanes; ++i) {
      if (!onoff[i]) continue;
      coef(1,0) += sincos[i];
      coef(1,1) += sin2[i];
      coef(1,2) += fDz[i] * sincos[i];
      coef(1,3) += fDz[i] * sin2[i];
    }
    for (Int_t i = 0; i < fgkPlanes; ++i) {
      if (!onoff[i]) continue;
      coef(2,0) += fDz[i] * cos2[i];
      coef(2,1) += fDz[i] * sincos[i];
      coef(2,2) += dz2[i] * cos2[i];
      coef(2,3) += dz2[i] * sincos[i];
    }
    for (Int_t i = 0; i < fgkPlanes; ++i) {
      if (!onoff[i]) continue;
      coef(3,0) += fDz[i] * sincos[i];
      coef(3,1) += fDz[i] * sin2[i];
      coef(3,2) += dz2[i] * sincos[i];
      coef(3,3) += dz2[i] * sin2[i];
    }
      
    TDecompLU *lu = new TDecompLU(4);
    lu->SetMatrix(coef);
    lu->SetTol(0.1*lu->GetTol());
    lu->Decompose();
    fLus.insert(pair<Int_t,TDecompLU*>(ipat,lu));
    TString buf = "";
    for (Int_t jp = 0; jp < fgkPlanes; ++jp) buf += Bool_t(ipat&(1<<jp));
    cout << " Determinant: " << buf << " " << ipat << " " << coef.Determinant() << endl;
    if (ipat == 255) { coef.Print(); cout << " Number of configurations: " << nTot << endl; }
  }

}
// -------------------------------------------------------------------------

// -----   Private method GetHits   ----------------------------------------
void CbmMuchFindVectors::GetHits()
{
  // Group hits according to their plane number
 
  for (Int_t ista = 0; ista < fgkStat; ++ista) {
    for (Int_t i = 0; i < fgkPlanes; ++i) fHitPl[ista][i].clear();
    for (Int_t i = 0; i < fgkPlanes / 2; ++i) fHit2d[ista][i].clear(); 
  }

  Int_t nHits = fHits->GetEntriesFast(), nSelTu[fgkStat] = {0}, sel = 0;
  for (Int_t i = 0; i < nHits; ++i) {
    CbmMuchStrawHit *hit = (CbmMuchStrawHit*) fHits->UncheckedAt(i);

    //!!! For debug - select hits with certain track IDs
    sel = 1; //SelectHitId(hit);
    if (!sel) continue;
    //

    Int_t detId = hit->GetAddress();
    CbmMuchModule* module = fGeoScheme->GetModuleByDetId(detId);
    if (module->GetDetectorType() != 2) continue; // skip GEM hits
    UInt_t address = CbmMuchAddress::GetElementAddress(detId, kMuchModule);
    Int_t station3 = CbmMuchAddress::GetStationIndex(address); // station
    Int_t doublet = CbmMuchAddress::GetLayerIndex(address); // doublet
    Int_t layer = CbmMuchAddress::GetLayerSideIndex(address); // layer in doublet
    //cout << hit->GetZ() << " " << station3 << " " << doublet << " " << layer << endl;
    //Int_t plane = (station3 - fStatFirst) * 8 + doublet * 2 + layer; 
    Int_t plane = doublet * 2 + layer; 
    fHitPl[station3-fStatFirst][plane].insert(pair<Int_t,Int_t>(hit->GetTube()+1000*hit->GetSegment(),i));
    if (fErrU < 0) fErrU = hit->GetDu();
    if (sel) ++nSelTu[station3-fStatFirst];
  }

  // Merge neighbouring hits from 2 layers of 1 doublet.
  // If there is no neighbour, takes hit from a single layer (to account for inefficiency)
  Int_t nlay2 = fgkPlanes / 2, indx1, indx2, tube1, tube2, next1, next2;
  CbmMuchStrawHit *hit1 = NULL, *hit2 = NULL;

  for (Int_t ista = 0; ista < fgkStat; ++ista) {
    // Loop over stations
    Int_t nSelDouble = 0;

    for (Int_t i1 = 0; i1 < nlay2; ++i1) {
      /* Debug
      cout << " Doublet: " << ista << " " << i1 << " " << fHitPl[ista][i1*2].size() << " " << fHitPl[ista][i1*2+1].size() << endl << " Layer 1: " << endl;
      for (multimap<Int_t,Int_t>::iterator it = fHitPl[ista][i1*2].begin(); it != fHitPl[ista][i1*2].end(); ++it) 
	cout << it->second << " ";
      cout << endl;
      for (multimap<Int_t,Int_t>::iterator it = fHitPl[ista][i1*2].begin(); it != fHitPl[ista][i1*2].end(); ++it) 
	cout << it->first << " ";
      cout << endl << " Layer 2: " << endl;
      for (multimap<Int_t,Int_t>::iterator it = fHitPl[ista][i1*2+1].begin(); it != fHitPl[ista][i1*2+1].end(); ++it) 
	cout << it->second << " ";
      cout << endl;
      for (multimap<Int_t,Int_t>::iterator it = fHitPl[ista][i1*2+1].begin(); it != fHitPl[ista][i1*2+1].end(); ++it) 
	cout << it->first << " ";
      cout << endl;
      */

      // Loop over doublets
      multimap<Int_t,Int_t>::iterator it1 = fHitPl[ista][i1*2].begin(), it2 = fHitPl[ista][i1*2+1].begin();
      multimap<Int_t,Int_t>::iterator it1end = fHitPl[ista][i1*2].end(), it2end = fHitPl[ista][i1*2+1].end();
      set<Int_t> tubeOk[2];
      next1 = next2 = 1;
      if (it1 == it1end) next1 = 0;
      if (it2 == it2end) next2 = 0;

      while (next1 || next2) {
	// Loop over tubes
	if (next1) {
	  indx1 = it1->second;
	  hit1 = (CbmMuchStrawHit*) fHits->UncheckedAt(indx1);
	  tube1 = it1->first;
	}
	if (next2) {
	  indx2 = it2->second;
	  hit2 = (CbmMuchStrawHit*) fHits->UncheckedAt(indx2);
	  tube2 = it2->first;
	}

	if (it2 != it2end && tube2 < tube1 || it1 == it1end) {
	  // Single layer hit2 ?
	  if (tubeOk[1].find(tube2) == tubeOk[1].end()) {
	    sel = SelDoubleId(-1, indx2);
	    nSelDouble += sel;
	    if (sel) fHit2d[ista][i1].push_back(pair<Int_t,Int_t>(-1,indx2));
	    tubeOk[1].insert(tube2);
	  }
	  ++it2;
	  next2 = 1;
	  next1 = 0;
	  if (it2 == fHitPl[ista][i1*2+1].end()) next2 = 0;
	  continue;
	}
	if (it1 != it1end && tube2 > tube1 + 1 || it2 == it2end) {
	  // Single layer hit1 ?
	  if (tubeOk[0].find(tube1) == tubeOk[0].end()) {
	    sel = SelDoubleId(indx1, -1);
	    nSelDouble += sel;
	    if (sel) fHit2d[ista][i1].push_back(pair<Int_t,Int_t>(indx1,-1));
	    tubeOk[0].insert(tube1);
	  }
	  ++it1;
	  next1 = 1;
	  next2 = 0;
	  if (it1 == fHitPl[ista][i1*2].end()) next1 = 0;
	  continue;
	}
	// Double layer hit
	sel = SelDoubleId(indx1, indx2);
	nSelDouble += sel;
	if (sel) fHit2d[ista][i1].push_back(pair<Int_t,Int_t>(indx1,indx2));
	tubeOk[0].insert(tube1);
	tubeOk[1].insert(tube2);
	if (tube2 == tube1) {
	  ++it2;
	  next2 = 1;
	  next1 = 0;
	  if (it2 == fHitPl[ista][i1*2+1].end()) {
	    next2 = 0;
	    next1 = 1;
	    if (it1 == fHitPl[ista][i1*2].end()) next1 = 0;
	  }
	} else {
	  ++it1;
	  next1 = 1;
	  next2 = 0;
	  if (it1 == fHitPl[ista][i1*2].end()) {
	    next1 = 0;
	    next2 = 1;
	    if (it2 == fHitPl[ista][i1*2+1].end()) next2 = 0;
	  }
	}
	continue;
      } // while (next1...
    }
    cout << " Selected tubes: " << ista << " " << nSelTu[ista] << endl;

    cout << " Selected doublets: " << ista << " " << nSelDouble << endl;
  }
}
// -------------------------------------------------------------------------

// -----   Private method SelectHitId   ------------------------------------
Bool_t CbmMuchFindVectors::SelectHitId(const CbmMuchStrawHit *hit)
{
  // Select hits with certain track IDs (for debugging)

  Int_t nSel = 2, idSel[2] = {0, 1}, id = 0;

  for (Int_t i = 0; i < nSel; ++i) {
    if (hit->GetFlag() % 2) {
    //if (0) {
      // Mirror hit
      return kFALSE;
    } else {
      CbmMuchDigiMatch* digiM = (CbmMuchDigiMatch*) fDigiMatches->UncheckedAt(hit->GetRefId());
      Int_t np = digiM->GetNofLinks();
      for (Int_t ip = 0; ip < np; ++ip) {
	CbmMuchPoint* point = (CbmMuchPoint*) fPoints->UncheckedAt(digiM->GetLink(ip).GetIndex());
	id = point->GetTrackID();
	if (id == idSel[i]) return kTRUE;
      }
    }
  }
  return kFALSE;
}
// -------------------------------------------------------------------------

// -----   Private method SelDoubleId   ------------------------------------
Bool_t CbmMuchFindVectors::SelDoubleId(Int_t indx1, Int_t indx2)
{
  // Select doublets with certain track IDs (for debugging)

  return kTRUE; // no selection 

  Int_t nId = 2, idSel[2] = {0, 1}, id = 0;
  CbmMuchStrawHit *hit = NULL;
  CbmMuchDigiMatch* digiM = NULL;
  CbmMuchPoint* point = NULL;

  if (indx1 >= 0) {
    hit = (CbmMuchStrawHit*) fHits->UncheckedAt(indx1);
    if (hit->GetFlag() % 2 == 0) {
      // Not a mirror hit
      for (Int_t i = 0; i < nId; ++i) {
	digiM = (CbmMuchDigiMatch*) fDigiMatches->UncheckedAt(hit->GetRefId());
	Int_t np = digiM->GetNofLinks();
	for (Int_t ip = 0; ip < np; ++ip) {
	  point = (CbmMuchPoint*) fPoints->UncheckedAt(digiM->GetLink(ip).GetIndex());
	  id = point->GetTrackID();
	  if (id == idSel[i]) return kTRUE;
	}
      }
    }
  }
  if (indx2 >= 0) {
    hit = (CbmMuchStrawHit*) fHits->UncheckedAt(indx2);
    if (hit->GetFlag() % 2 == 0) {
      // Not a mirror hit
      for (Int_t i = 0; i < nId; ++i) {
	digiM = (CbmMuchDigiMatch*) fDigiMatches->UncheckedAt(hit->GetRefId());
	Int_t np = digiM->GetNofLinks();
	for (Int_t ip = 0; ip < np; ++ip) {
	  point = (CbmMuchPoint*) fPoints->UncheckedAt(digiM->GetLink(ip).GetIndex());
	  id = point->GetTrackID();
	  if (id == idSel[i]) return kTRUE;
	}
      }
    }
  }
  return kFALSE;
}
// -------------------------------------------------------------------------

// -----   Private method MakeVectors   ------------------------------------
void CbmMuchFindVectors::MakeVectors()
{
  // Make vectors for stations
 
  for (Int_t ista = 0; ista < fgkStat; ++ista) {
    Int_t nvec = fVectors[ista].size();
    for (Int_t j = 0; j < nvec; ++j) delete fVectors[ista][j];
    fVectors[ista].clear();
    Int_t lay2 = 0, patt = 0, flag = 0, ndoubl = fHit2d[ista][lay2].size();
    CbmMuchStrawHit *hit = NULL;

    cout << " Doublets: " << ista << " " << ndoubl << endl;
    for (Int_t id = 0; id < ndoubl; ++id) {
      Int_t indx1 = fHit2d[ista][lay2][id].first;
      Int_t indx2 = fHit2d[ista][lay2][id].second;
      if (indx1 >= 0) {
	hit = (CbmMuchStrawHit*) fHits->UncheckedAt(indx1);
	fUz[lay2*2][0] = hit->GetU();
	//fUz[lay2*2][2] = hit->GetPhi();
	fUzi[lay2*2][0] = hit->GetSegment();
	fUzi[lay2*2][1] = indx1;
	fUzi[lay2*2][2] = hit->GetTube();
      }
      if (indx2 >= 0) {
	hit = (CbmMuchStrawHit*) fHits->UncheckedAt(indx2);
	fUz[lay2*2+1][0] = hit->GetU();
	//fUz[lay2*2+1][2] = hit->GetPhi();
	fUzi[lay2*2+1][0] = hit->GetSegment();
	fUzi[lay2*2+1][1] = indx2;
	fUzi[lay2*2+1][2] = hit->GetTube();
      }
      Bool_t ind1 = indx1 + 1;
      Bool_t ind2 = indx2 + 1;
      patt = ind1;
      patt |= (ind2 << 1);
      //cout << plane0 << " " << hit->GetX() << " " << hit->GetY() << " " << hit->GetZ() << " " << hit->GetU() << " " << u << endl;
      ProcessDouble(ista, lay2+1, patt, flag, hit->GetTube(), hit->GetSegment());
    }
  }
}
// -------------------------------------------------------------------------

// -----   Private method ProcessDouble   ----------------------------------
void CbmMuchFindVectors::ProcessDouble(Int_t ista, Int_t lay2, Int_t patt, Int_t flag, 
				       Int_t tube0, Int_t segment0)
{
  // Main processing engine (recursively adds doublet hits to the vector)
 
  // !!! Tube differences between the same views for mu from omega at 8 GeV !!!
  const Int_t dTubes2 = 30; 
  Double_t pars[4] = {0.0};

  Int_t ndoubl = fHit2d[ista][lay2].size();

  for (Int_t id = 0; id < ndoubl; ++id) {
    Int_t indx1 = fHit2d[ista][lay2][id].first;
    Int_t indx2 = fHit2d[ista][lay2][id].second;
    CbmMuchStrawHit *hit = (CbmMuchStrawHit*) fHits->UncheckedAt(TMath::Max(indx1,indx2));
    Int_t segment = hit->GetSegment();
    Int_t tube = hit->GetTube();
    //if (segment != segment0) continue; // do not combine two half-stations - wrong due to stereo angles

    if (TMath::Abs(tube - tube0) > fDtubes[ista][lay2-1]) continue; // !!! cut

    // Check the same views
    Int_t ok = 1;
    for (Int_t il = 0; il < lay2; ++il) {
      Int_t pl = il * 2;
      if (TMath::Abs(fSina[pl]-fSina[lay2*2]) < 0.01) {
	// The same views
	Int_t seg = fUzi[pl][0];
	if (!(patt & (1 << pl))) seg = fUzi[pl+1][0];
	if (segment != seg) { ok = 0; break; }
	// Check tube difference 
	Double_t z = fDz[pl];
	Int_t tu = fUzi[pl][2];
	if (!(patt & (1 << pl))) { z = fDz[pl+1]; tu = fUzi[pl+1][2]; }
	z += fZ0[ista];
	Double_t dzz = (hit->GetZ() - z) / z;
	if (TMath::Abs(tube - tu - dzz * tu) > dTubes2) { ok = 0; break; } // !!! cut
      }
    }
    if (!ok) continue; // !!! cut

    /*
    if (lay2 > 1) {
      // Tube difference with previous to previous doublet
      Int_t pl = (lay2 - 2) * 2;
      Int_t tu = fUzi[pl][2];
      if (patt & (1 << pl+1)) tu = fUzi[pl+1][2];
      Double_t dtu = tube - tu;
      if (lay2 == 3) dtu -= slope[ista] * tu;
      //if (TMath::Abs(dtu) > dTubes2[lay2-2]) continue; // !!! cut
    }
    */

    if (indx1 >= 0) {
      hit = (CbmMuchStrawHit*) fHits->UncheckedAt(indx1);
      fUz[lay2*2][0] = hit->GetU();
      //fUz[lay2*2][2] = hit->GetPhi();
      fUzi[lay2*2][0] = hit->GetSegment();
      fUzi[lay2*2][1] = indx1;
      fUzi[lay2*2][2] = hit->GetTube();
    }
    if (indx2 >= 0) {
      hit = (CbmMuchStrawHit*) fHits->UncheckedAt(indx2);
      fUz[lay2*2+1][0] = hit->GetU();
      //fUz[lay2*2+1][2] = hit->GetPhi();
      fUzi[lay2*2+1][0] = hit->GetSegment();
      fUzi[lay2*2+1][1] = indx2;
      fUzi[lay2*2+1][2] = hit->GetTube();
    }

    // Check intersection
    //if (!IntersectViews(ista, lay2, indx1, indx2, patt)) continue;

    Bool_t ind1 = indx1 + 1;
    Bool_t ind2 = indx2 + 1;
    // Clear bits
    patt &= ~(1 << lay2*2);
    patt &= ~(1 << lay2*2+1);
    // Set bits
    patt |= (ind1 << lay2*2);
    patt |= (ind2 << lay2*2+1);
    //cout << plane << " " << patt << " " << hit->GetX() << " " << hit->GetY() << " " << hit->GetZ() << " " << hit->GetU() << " " << u << endl;

    if (lay2 + 1 < fgkPlanes / 2) ProcessDouble(ista, lay2+1, patt, flag, tube, segment);
    else {
      // Straight line fit of the vector
      FindLine(patt, pars);
      Double_t chi2 = FindChi2(ista, patt, pars);
      //cout << " *** Stat: " << ista << " " << id << " " << indx1 << " " << indx2 << " " << chi2 << " " << pars[0] << " " << pars[1] << endl;
      if (chi2 <= fCutChi2) AddVector(ista, patt, chi2, pars); // add vector to the temporary container
    }
  } // for (id = 0; id < ndoubl;
}
// -------------------------------------------------------------------------

// -----   Private method IntersectViews   ---------------------------------
Bool_t CbmMuchFindVectors::IntersectViews(Int_t ista, Int_t curLay, Int_t indx1, Int_t indx2, Int_t patt)
{
  // Intersect 2 views 

  Int_t lay2 = curLay * 2;
  if (indx1 < 0) ++lay2;
  Double_t u2 = fUz[lay2][0];

  Int_t lay1 = curLay * 2 - 2;
  if (!(patt & (1 << lay1))) ++lay1;
  Double_t u1 = fUz[lay1][0];
  
  Double_t yint = u1 * fCosa[lay2] - u2 * fCosa[lay1];
  yint /= (fSina[lay1] * fCosa[lay2] - fSina[lay2] * fCosa[lay1]);
  if (TMath::Abs(yint) > fRmax[ista] + 10.0) return kFALSE; // outside outer dim. + safety margin 

  Double_t xint = u2 / fCosa[lay2] - yint * fSina[lay2] / fCosa[lay2];

  Double_t v1 = -xint * fSina[lay1] + yint * fCosa[lay1];
  Double_t v2 = -xint * fSina[lay2] + yint * fCosa[lay2];

  cout << xint << " " << yint << " " << v1 << " " << v2 << " " << fUzi[lay1][0] << " " << fUzi[lay2][0] << endl;
  if (TMath::Abs(v1) > 10.0 && v1 * fUzi[lay1][0] < 0) cout << " Outside !!! " << endl;
  if (TMath::Abs(v2) > 10.0 && v2 * fUzi[lay2][0] < 0) cout << " Outside !!! " << endl;
  if (TMath::Abs(v1) > 30.0 && v1 * fUzi[lay1][0] < 0) return kFALSE;
  if (TMath::Abs(v2) > 30.0 && v2 * fUzi[lay2][0] < 0) return kFALSE;
  return kTRUE;
}
// -------------------------------------------------------------------------

// -----   Private method AddVector   --------------------------------------
void CbmMuchFindVectors::AddVector(Int_t ista, Int_t patt, Double_t chi2, Double_t *pars, Bool_t lowRes)
{
  // Add vector to the temporary container (as a MuchTrack)

  CbmMuchTrack *track = new CbmMuchTrack();
  track->SetChiSq(chi2);
  TMatrixFSym cov(5);
  FairTrackParam par(pars[0], pars[1], fZ0[ista], pars[2], pars[3], 0.0, cov);
  track->SetParamFirst(&par);
  par.SetZ(fZ0[ista] + fDz[fgkPlanes-1]);
  par.SetX(pars[0] + fDz[fgkPlanes-1] * pars[2]);
  par.SetY(pars[1] + fDz[fgkPlanes-1] * pars[3]);
  track->SetParamLast(&par);
  track->SetPreviousTrackId(ista); // just to pass the value

  for (Int_t ipl = 0; ipl < fgkPlanes; ++ipl) {
    if (!(patt & (1 << ipl))) continue;
    track->AddHit(fUzi[ipl][1], kMUCHSTRAWHIT);
    if (lowRes) continue;
    // Store selected hit coordinate (resolved left-right ambig.) as data member fDphi  
    CbmMuchStrawHit *hit = (CbmMuchStrawHit*) fHits->UncheckedAt(fUzi[ipl][1]);
    hit->SetDphi(fUz[ipl][0]);
  }
  SetTrackId(track); // set track ID as its flag 
  if (lowRes) fVectors[ista].push_back(track);
  else fVectorsHigh[ista].push_back(track);
}
// -------------------------------------------------------------------------

// -----   Private method SetTrackId   -------------------------------------
void CbmMuchFindVectors::SetTrackId(CbmMuchTrack *vec)
{
  // Set vector ID as its flag (maximum track ID of its poins)

  map<Int_t,Int_t> ids;
  Int_t nhits = vec->GetNofHits(), id = 0;

  for (Int_t ih = 0; ih < nhits; ++ih) {
    CbmMuchStrawHit *hit = (CbmMuchStrawHit*) fHits->UncheckedAt(vec->GetHitIndex(ih));
    if (hit->GetFlag() % 2) {
    //if (0) {
      // Mirror hit
      id = -1; 
      if (ids.find(id) == ids.end()) ids.insert(pair<Int_t,Int_t>(id,1));
      else ++ids[id];
    } else {
      CbmMuchDigiMatch* digiM = (CbmMuchDigiMatch*) fDigiMatches->UncheckedAt(hit->GetRefId());
      Int_t np = digiM->GetNofLinks();
      for (Int_t ip = 0; ip < np; ++ip) {
	//CbmMuchPoint* point = (CbmMuchPoint*) fPoints->UncheckedAt(digiM->GetLink(0).GetIndex());
	CbmMuchPoint* point = (CbmMuchPoint*) fPoints->UncheckedAt(digiM->GetLink(ip).GetIndex());
	id = point->GetTrackID();
	//if (np > 1) cout << ip << " " << id << endl;
	if (ids.find(id) == ids.end()) ids.insert(pair<Int_t,Int_t>(id,1));
	else ++ids[id];
      }
      //if (np > 1) { cout << " digi " << digiM->GetNofLinks() << " " << ista << " " << hit->GetX() << " " << hit->GetY() << endl; exit(0); }
    }
  }
  Int_t maxim = -1, idmax = -9;
  for (map<Int_t,Int_t>::iterator it = ids.begin(); it != ids.end(); ++it) {
    if (it->second > maxim) {
      maxim = it->second;
      idmax = it->first;
    }
  }
  // Set vector ID as its flag
  vec->SetFlag(idmax);
}
// -------------------------------------------------------------------------

// -----   Private method FindLine   ---------------------------------------
void CbmMuchFindVectors::FindLine(Int_t patt, Double_t *pars)
{
  // Fit of hits to the straight line

  // Solve system of linear equations
  Bool_t ok = kFALSE, onoff;
  TVectorD b(4);
  for (Int_t i = 0; i < fgkPlanes; ++i) {
    onoff = patt & (1 << i);
    if (!onoff) continue;
    b[0] += fUz[i][0] * fCosa[i];
    b[1] += fUz[i][0] * fSina[i];
    b[2] += fUz[i][0] * fDz[i] * fCosa[i];
    b[3] += fUz[i][0] * fDz[i] * fSina[i];
  }

  //lu.Print();
  TVectorD solve = fLus[patt]->Solve(b, ok); 
  //TVectorD solve = lu.TransSolve(b, ok);
  //lu.Print();
  for (Int_t i = 0; i < 4; ++i) pars[i] = solve[i];
  //Double_t y1 = cosa / sina * (uz[1][0] * cosa - uz[0][0]) + uz[1][0] * sina;
  //Double_t y2 = -cosa / sina * (uz[2][0] * cosa - uz[0][0]) - uz[2][0] * sina;
  //cout << " OK " << ok << " " << y1 << " " << y2 << endl;
}
// -------------------------------------------------------------------------

// -----   Private method FindChi2   ---------------------------------------
Double_t CbmMuchFindVectors::FindChi2(Int_t ista, Int_t patt, Double_t *pars)
{
  // Compute chi2 of the fit
	
  Double_t chi2 = 0, x = 0, y = 0, u = 0, errv = 1.;
  if (fErrU > 0.1) errv = 10;
  static Int_t first = 1;
  if (first) {
    first = 0;
    /*
    mcFile->Get("FairBaseParSet");
    cout << gGeoManager << " " << gGeoManager->GetVolume("muchstation05") << " " << gGeoManager->GetVolume("muchstation06") << endl;
    for (Int_t i = 0; i < 2; ++i) {
      TString volName = "muchstation0";
      volName += (i+4);
      TGeoVolume *vol = gGeoManager->GetVolume(volName);
      TGeoTube *shape = (TGeoTube*) vol->GetShape(); 
      rad[i] = shape->GetRmin();
    }
    cout << " Rads: " << rad[0] << " " << rad[1] << endl;
    */
  }

  Bool_t onoff;
  for (Int_t i = 0; i < fgkPlanes; ++i) {
    onoff = patt & (1 << i);
    if (!onoff) continue;
    x = pars[0] + pars[2] * fDz[i];
    y = pars[1] + pars[3] * fDz[i];
    u = x * fCosa[i] + y * fSina[i];
    Double_t du = (u - fUz[i][0]) / fErrU;
    chi2 += du * du;
    //cout << " " << i << " " << x << " " << y << " " << u << " " <<  fUz[i][0] << " " << du*du << endl;

    // Edge effect
    //if (errv < 2.0) continue; // skip for high-res. mode  
    Int_t iseg = fUzi[i][0];
    Double_t v = -x * fSina[i] + y * fCosa[i];
    Double_t v0 = 0;
    //cout << v << " " << iseg << endl;
    if (TMath::Abs(fUz[i][0]) > fRmin[ista] && v * iseg > 0) continue;

    if (TMath::Abs(fUz[i][0]) < fRmin[ista]) {
      v0 = TMath::Sign(TMath::Sqrt(fRmin[ista]*fRmin[ista]-fUz[i][0]*fUz[i][0]),iseg*1.); // beam hole
      if ((v-v0) * iseg > 0) continue;
    }
    Double_t dv = (v - v0) / errv;
    chi2 += dv * dv;
  }
  //cout << " Chi2 = " << chi2 << endl;
  return chi2;
}
// -------------------------------------------------------------------------

// -----   Private method CheckParams   ------------------------------------
void CbmMuchFindVectors::CheckParams()
{
  // Remove vectors with wrong orientation
  // using empirical cuts for omega muons at 8 Gev

  Double_t cut[2] = {0.6, 0.7}; // !!! empirical !!!

  for (Int_t ista = 0; ista < fgkStat; ++ista) {
    Int_t nvec = fVectors[ista].size();

    for (Int_t iv = 0; iv < nvec; ++iv) {
      CbmMuchTrack *vec = fVectors[ista][iv];
      const FairTrackParam *params = vec->GetParamFirst();
      Double_t dTx = params->GetTx() - params->GetX() / params->GetZ();
      Double_t dTy = params->GetTy() - params->GetY() / params->GetZ();
      if (TMath::Abs(dTx) > cut[0] || TMath::Abs(dTy) > cut[1]) vec->SetChiSq(-1.0);
    }

    for (Int_t iv = nvec-1; iv >= 0; --iv) {
      CbmMuchTrack *vec = fVectors[ista][iv];
      if (vec->GetChiSq() < 0) {
	delete fVectors[ista][iv]; 
	fVectors[ista].erase(fVectors[ista].begin()+iv); 
      }
    }
    cout << " Vectors after parameter check: " << nvec << " " << fVectors[ista].size() << endl;
  }
}
// -------------------------------------------------------------------------

// -----   Private method HighRes   ----------------------------------------
void CbmMuchFindVectors::HighRes()
{
  // High resolution processing (resolve ghost hits and make high resolution vectors)

  for (Int_t ista = 0; ista < fgkStat; ++ista) {
    Int_t nvec = fVectors[ista].size();

    for (Int_t iv = 0; iv < nvec; ++iv) {
      CbmMuchTrack *vec = fVectors[ista][iv];
      Int_t nhits = vec->GetNofHits(), patt = 0;
      Double_t uu[fgkPlanes][2];

      for (Int_t ih = 0; ih < nhits; ++ih) {
	CbmMuchStrawHit *hit = (CbmMuchStrawHit*) fHits->UncheckedAt(vec->GetHitIndex(ih));
	Int_t lay = fGeoScheme->GetLayerIndex(hit->GetAddress());
	Int_t side = fGeoScheme->GetLayerSideIndex(hit->GetAddress());
	Int_t plane = lay*2+side;
	uu[plane][0] = hit->GetU();
	uu[plane][1] = hit->GetDouble()[2];
	patt |= (1 << plane);
	fUzi[plane][0] = hit->GetSegment();
	fUzi[plane][1] = vec->GetHitIndex(ih);
      }

      // Number of hit combinations is 2 
      // - left-right ambiguity resolution does not really work for doublets
      Int_t nCombs = (patt & 1) ? 2 : 1, flag = 1, nok = nCombs - 1;

      for (Int_t icomb = -1; icomb < nCombs; icomb += 2) {
	fUz[0][0] = (nCombs == 2) ? uu[0][0] + uu[0][1] * icomb : 0.0;
	ProcessSingleHigh(ista, 1, patt, flag, nok, uu);
      }
      
    } // for (Int_t iv = 0; 
  } // for (Int_t ista = 0; 

  MoveVectors(); // move vectors from one container to another, i.e. drop low resolution ones

}
// -------------------------------------------------------------------------

// -----   Private method ProcessDoubleHigh   ------------------------------
void CbmMuchFindVectors::ProcessSingleHigh(Int_t ista, Int_t plane, Int_t patt, Int_t flag,
					   Int_t nok, Double_t uu[fgkPlanes][2]) 
{
  // Main processing engine for high resolution mode
  // (recursively adds singlet hits to the vector)
 
  Double_t pars[4] = {0.0};

  // Number of hit combinations is 2
  Int_t nCombs = (patt & (1 << plane)) ? 2 : 1;
  nok += (nCombs - 1);

  for (Int_t icomb = -1; icomb < nCombs; icomb += 2) {
    fUz[plane][0] = (nCombs == 2) ? uu[plane][0] + uu[plane][1] * icomb : 0.0;
    if (plane == fgkPlanes - 1 || nok == fMinHits && flag) {
      // Straight line fit of the vector
      Int_t patt1 = patt & ((1 << plane + 1) - 1); // apply mask
      FindLine(patt1, pars);
      Double_t chi2 = FindChi2(ista, patt1, pars);
      //cout << " *** Stat: " << ista << " " << plane << " " << chi2 << " " << pars[0] << " " << pars[1] << endl;
      if (icomb > -1) flag = 0;
      if (chi2 > fCutChi2) continue; // too high chi2 - do not extend line
      //if (plane + 1 < fgkPlanes) ProcessSingleHigh(ista, plane + 1, patt, flag, nok, uu);
      if (plane + 1 < fgkPlanes) ProcessSingleHigh(ista, plane + 1, patt, 0, nok, uu);
      else AddVector(ista, patt, chi2, pars, kFALSE); // add vector to the temporary container
    } else {
      ProcessSingleHigh(ista, plane + 1, patt, flag, nok, uu);
    }
  }

}
// -------------------------------------------------------------------------

// -----   Private method MoveVectors   ------------------------------------
void CbmMuchFindVectors::MoveVectors()
{
  // Drop low-resolution vectors and move high-res. ones to their container

  for (Int_t ista = 0; ista < fgkStat; ++ista) {
    Int_t nVecs = fVectors[ista].size();
    for (Int_t j = 0; j < nVecs; ++j) delete fVectors[ista][j];
    fVectors[ista].clear();
    
    nVecs = fVectorsHigh[ista].size();
    for (Int_t j = 0; j < nVecs; ++j) fVectors[ista].push_back(fVectorsHigh[ista][j]);
  }
}
// -------------------------------------------------------------------------

// -----   Private method RemoveClones   -----------------------------------
void CbmMuchFindVectors::RemoveClones()
{
  // Remove clone vectors (having at least 1 the same hit in each doublet (min. 4 the same hits))
 
  Int_t nthr = 4, planes[20];

  for (Int_t ista = 0; ista < fgkStat; ++ista) {
    Int_t nvec = fVectors[ista].size();

    // Do sorting according to "quality"
    multimap<Double_t,CbmMuchTrack*> qMap;
    multimap<Double_t,CbmMuchTrack*>::iterator it, it1;

    for (Int_t iv = 0; iv < nvec; ++iv) {
      CbmMuchTrack *vec = fVectors[ista][iv];
      Double_t qual = vec->GetNofHits() + (99 - TMath::Min(vec->GetChiSq(),99.0)) / 100;
      qMap.insert(pair<Double_t,CbmMuchTrack*>(-qual,vec));
    }
    
    for (it = qMap.begin(); it != qMap.end(); ++it) {
      CbmMuchTrack *vec = it->second;
      if (vec->GetChiSq() < 0) continue;
      for (Int_t j = 0; j < fgkPlanes; ++j) planes[j] = -1;

      Int_t nhits = vec->GetNofHits();
      for (Int_t ih = 0; ih < nhits; ++ih) {
	CbmMuchStrawHit *hit = (CbmMuchStrawHit*) fHits->UncheckedAt(vec->GetHitIndex(ih));
	Int_t lay = fGeoScheme->GetLayerIndex(hit->GetAddress());
	Int_t side = fGeoScheme->GetLayerSideIndex(hit->GetAddress());
	planes[lay*2+side] = vec->GetHitIndex(ih);
	//cout << iv << " " << lay*2+side << " " << vec->GetHitIndex(ih) << endl;
      }

      it1 = it;
      for (++it1; it1 != qMap.end(); ++it1) {
	CbmMuchTrack *vec1 = it1->second;
	if (vec1->GetChiSq() < 0) continue;
	Int_t nsame = 0, same[fgkPlanes/2] = {0};

	Int_t nhits1 = vec1->GetNofHits();
	//nthr = TMath::Min(nhits,nhits1) / 2;
	//nthr = TMath::Min(nhits,nhits1) * 0.75;
	for (Int_t ih = 0; ih < nhits1; ++ih) {
	  CbmMuchStrawHit *hit = (CbmMuchStrawHit*) fHits->UncheckedAt(vec1->GetHitIndex(ih));
	  Int_t lay = fGeoScheme->GetLayerIndex(hit->GetAddress());
	  Int_t side = fGeoScheme->GetLayerSideIndex(hit->GetAddress());
	  if (planes[lay*2+side] >= 0) {
	    if (vec1->GetHitIndex(ih) == planes[lay*2+side]) same[lay] = 1;
	    //else same[lay] = 0;
	  }
	}
	for (Int_t lay = 0; lay < fgkPlanes/2; ++lay) nsame += same[lay];

	if (nsame >= nthr) {
	  // Too many the same hits
	  Int_t clone = 0;
	  if (nhits > nhits1 + 0) clone = 1;
	  //else if (vec->GetChiSq() * 3.0 <= vec1->GetChiSq()) vec1->SetChiSq(-1.0); // the same number of hits on 2 tracks
	  else if (fgkPlanes > -8 && vec->GetChiSq() * 1 <= vec1->GetChiSq()) clone = 1; // the same number of hits on 2 tracks
	  if (clone) {
	    vec1->SetChiSq(-1.0);
	    /* Debug
	    const FairTrackParam *params = vec->GetParamFirst();
	    const FairTrackParam *params1 = vec1->GetParamFirst();
	    if (vec1->GetFlag() < 2) cout << " Remove: " << vec->GetFlag() << " " << vec1->GetFlag() << " " << nhits << " " << nhits1 << " " << nsame << " " << vec->GetChiSq() << " " << vec1->GetChiSq() << " " << params->GetX() << " " << params1->GetX() << " " << params->GetY() << " " << params1->GetY() << endl;
	    //
	    Double_t dx = params->GetX() - params1->GetX();
	    dx /= 0.2;
	    Double_t dy = params->GetY() - params1->GetY();
	    dy /= 1.5;
	    Double_t chi2 = dx * dx + dy * dy;
	    if (chi2 < 10) vec1->SetChiSq(-1.0);
	    */
	  }
	}
      }
    }

    for (Int_t iv = nvec-1; iv >= 0; --iv) {
      CbmMuchTrack *vec = fVectors[ista][iv];
      if (vec->GetChiSq() < 0) {
	delete fVectors[ista][iv]; 
	fVectors[ista].erase(fVectors[ista].begin()+iv); 
      }
    }
    cout << " Vectors after clones removed: " << nvec << " " << fVectors[ista].size() << endl;

  } // for (Int_t ista = 0; ista < fgkStat;
}
// -------------------------------------------------------------------------

// -----   Private method RemoveShorts   -----------------------------------
void CbmMuchFindVectors::RemoveShorts()
{
  // Remove short tracks

  Int_t nshort = fgkPlanes / 2, planes[20];

  for (Int_t ista = 0; ista < fgkStat; ++ista) {
    Int_t nvec = fVectors[ista].size();
    Int_t remove = 0;

    for (Int_t iv = 0; iv < nvec; ++iv) {
      CbmMuchTrack *vec = fVectors[ista][iv];
      if (vec->GetChiSq() < 0) continue;
      Int_t nhits = vec->GetNofHits();
      if (nhits != nshort) continue;
      set<Int_t> overlap;
      //multiset<Int_t> overlap1;
      for (Int_t j = 0; j < fgkPlanes; ++j) planes[j] = -1;
      for (Int_t ih = 0; ih < nhits; ++ih) {
	CbmMuchStrawHit *hit = (CbmMuchStrawHit*) fHits->UncheckedAt(vec->GetHitIndex(ih));
	Int_t lay = fGeoScheme->GetLayerIndex(hit->GetAddress());
	Int_t side = fGeoScheme->GetLayerSideIndex(hit->GetAddress());
	planes[lay*2+side] = vec->GetHitIndex(ih);
      }

      for (Int_t iv1 = iv + 1; iv1 < nvec; ++iv1) {
	CbmMuchTrack *vec1 = fVectors[ista][iv1];
	if (vec1->GetChiSq() < 0) continue;
	Int_t nhits1 = vec1->GetNofHits();
	
	// Compare hits
	for (Int_t ih = 0; ih < nhits1; ++ih) { 
	  CbmMuchStrawHit *hit = (CbmMuchStrawHit*) fHits->UncheckedAt(vec1->GetHitIndex(ih));
	  Int_t lay = fGeoScheme->GetLayerIndex(hit->GetAddress());
	  Int_t side = fGeoScheme->GetLayerSideIndex(hit->GetAddress());
	  if (vec1->GetHitIndex(ih) == planes[lay*2+side] && planes[lay*2+side] >= 0) overlap.insert(ih);
	}
	//if (overlap.size() == nshort) {
	if (overlap.size() > 0) {
	  // Hits are shared with other tracks
	  remove = 1;
	  break;
	}
      } // for (Int_t iv1 = iv + 1;
      if (remove) vec->SetChiSq(-1.0);
    } // for (Int_t iv = 0; iv < nvec;

    for (Int_t iv = nvec-1; iv >= 0; --iv) {
      CbmMuchTrack *vec = fVectors[ista][iv];
      if (vec->GetChiSq() < 0) {
	delete fVectors[ista][iv]; 
	fVectors[ista].erase(fVectors[ista].begin()+iv); 
      }
    }
    cout << " Vectors after shorts removed: " << nvec << " " << fVectors[ista].size() << endl;

  } // for (Int_t ista = 0; 
}
// -------------------------------------------------------------------------
 
// -----   Private method StoreVectors   -----------------------------------
void CbmMuchFindVectors::StoreVectors()
{
  // Store vectors (CbmMuchTracks) into TClonesArray

  Int_t ntrs = 0;
  Int_t nHitsTot = fHits->GetEntriesFast();

  for (Int_t ist = 0; ist < fgkStat; ++ist) {
    set<Int_t> usedHits;
    Int_t nvec = fVectors[ist].size();

    for (Int_t iv = 0; iv < nvec; ++iv) {
      CbmMuchTrack *tr = new ((*fTrackArray)[ntrs++]) CbmMuchTrack(*(fVectors[ist][iv]));
      //cout << " Track: " << tr->GetNofHits() << endl;
      //for (Int_t j = 0; j < tr->GetNofHits(); ++j) cout << j << " " << tr->GetHitIndex(j) << " " << fVectors[ist][iv]->GetHitIndex(j) << endl;
      // Set hit flag (to check Lit tracking)
      Int_t nhits = tr->GetNofHits();
      /*
      for (Int_t j = 0; j < nhits; ++j) {
	CbmMuchStrawHit *hit = (CbmMuchStrawHit*) fHits->UncheckedAt(tr->GetHitIndex(j));
	if (usedHits.find(tr->GetHitIndex(j)) == usedHits.end()) {
	  hit->SetFlag(ntrs-1);
	  usedHits.insert(tr->GetHitIndex(j));
	} else {
	  // Ugly interim solution for the tracking - create new hit
	  CbmMuchStrawHit *hitNew = new ((*fHits)[nHitsTot++]) CbmMuchStrawHit(*hit);
	  hitNew->SetFlag(ntrs-1);
	  usedHits.insert(nHitsTot-1);
	}
      }
      */
    }
  }
}
// -------------------------------------------------------------------------

// -----   Private method CountBits   --------------------------------------
//This is better when most bits in x are 0
//It uses 3 arithmetic operations and one comparison/branch per "1" bit in x.
// Wikipedia "Hamming weight"
Int_t CbmMuchFindVectors::CountBits(Int_t x) 
{

  Int_t count;
  for (count=0; x; count++)
    x &= x-1;
  return count;
}

// -------------------------------------------------------------------------

ClassImp(CbmMuchFindVectors);