+#include "AliVertexerTracks.h"
+
+ClassImp(AliVertexerTracks)
+
+
+//----------------------------------------------------------------------------
+AliVertexerTracks::AliVertexerTracks():
+TObject(),
+fVert(),
+fCurrentVertex(0),
+fMode(0),
+fFieldkG(-999.),
+fTrkArraySel(),
+fIdSel(0),
+fTrksToSkip(0),
+fNTrksToSkip(0),
+fConstraint(kFALSE),
+fOnlyFitter(kFALSE),
+fMinTracks(1),
+fMinClusters(5),
+fDCAcut(0.1),
+fDCAcutIter0(0.1),
+fNSigma(3.),
+fMaxd0z0(0.5),
+fMinDetFitter(100.),
+fMaxTgl(1000.),
+fITSrefit(kTRUE),
+fFiducialR(3.),
+fFiducialZ(30.),
+fnSigmaForUi00(1.5),
+fAlgo(1),
+fAlgoIter0(4)
+{
+//
+// Default constructor
+//
+ SetVtxStart();
+ SetVtxStartSigma();
+}
+//----------------------------------------------------------------------------
+AliVertexerTracks::AliVertexerTracks(Double_t fieldkG):
+TObject(),
+fVert(),
+fCurrentVertex(0),
+fMode(0),
+fFieldkG(fieldkG),
+fTrkArraySel(),
+fIdSel(0),
+fTrksToSkip(0),
+fNTrksToSkip(0),
+fConstraint(kFALSE),
+fOnlyFitter(kFALSE),
+fMinTracks(1),
+fMinClusters(5),
+fDCAcut(0.1),
+fDCAcutIter0(0.1),
+fNSigma(3.),
+fMaxd0z0(0.5),
+fMinDetFitter(100.),
+fMaxTgl(1000.),
+fITSrefit(kTRUE),
+fFiducialR(3.),
+fFiducialZ(30.),
+fnSigmaForUi00(1.5),
+fAlgo(1),
+fAlgoIter0(4)
+{
+//
+// Standard constructor
+//
+ SetVtxStart();
+ SetVtxStartSigma();
+}
+//-----------------------------------------------------------------------------
+AliVertexerTracks::~AliVertexerTracks()
+{
+ // Default Destructor
+ // The objects pointed by the following pointer are not owned
+ // by this class and are not deleted
+ fCurrentVertex = 0;
+ if(fTrksToSkip) { delete fTrksToSkip; fTrksToSkip=NULL; }
+ if(fIdSel) { delete fIdSel; fIdSel=NULL; }
+}
+//----------------------------------------------------------------------------
+AliESDVertex* AliVertexerTracks::FindPrimaryVertex(AliVEvent *vEvent)
+{
+//
+// Primary vertex for current ESD or AOD event
+// (Two iterations:
+// 1st with 5*fNSigma*sigma cut w.r.t. to initial vertex
+// + cut on sqrt(d0d0+z0z0) if fConstraint=kFALSE
+// 2nd with fNSigma*sigma cut w.r.t. to vertex found in 1st iteration)
+//
+ fCurrentVertex = 0;
+
+ TString evtype = vEvent->IsA()->GetName();
+ Bool_t inputAOD = ((evtype=="AliAODEvent") ? kTRUE : kFALSE);
+
+ if(inputAOD && fMode==1) {
+ printf("Error : AliVertexerTracks: no TPC-only vertex from AOD\n");
+ TooFewTracks();
+ return fCurrentVertex;
+ }
+
+ // accept 1-track case only if constraint is available
+ if(!fConstraint && fMinTracks==1) fMinTracks=2;
+
+ // read tracks from AlivEvent
+ Int_t nTrks = (Int_t)vEvent->GetNumberOfTracks();
+ if(nTrks<fMinTracks) {
+ TooFewTracks();
+ return fCurrentVertex;
+ }
+ //
+
+ TDirectory * olddir = gDirectory;
+ TFile *f = 0;
+ if(nTrks>500) f = new TFile("VertexerTracks.root","recreate");
+ TObjArray trkArrayOrig(nTrks);
+ UShort_t *idOrig = new UShort_t[nTrks];
+
+ Int_t nTrksOrig=0;
+ AliExternalTrackParam *t=0;
+ // loop on tracks
+ for(Int_t i=0; i<nTrks; i++) {
+ AliVTrack *track = (AliVTrack*)vEvent->GetTrack(i);
+ // check tracks to skip
+ Bool_t skipThis = kFALSE;
+ for(Int_t j=0; j<fNTrksToSkip; j++) {
+ if(track->GetID()==fTrksToSkip[j]) {
+ AliDebug(1,Form("skipping track: %d",i));
+ skipThis = kTRUE;
+ }
+ }
+ if(skipThis) continue;
+
+ // kITSrefit
+ if(fMode==0 && fITSrefit && !(track->GetStatus()&AliESDtrack::kITSrefit)) continue;
+
+ if(!inputAOD) { // ESD
+ AliESDtrack* esdt = (AliESDtrack*)track;
+ if(esdt->GetNcls(fMode) < fMinClusters) continue;
+ if(fMode==0) { // ITS mode
+ Double_t x,p[5],cov[15];
+ esdt->GetExternalParameters(x,p);
+ esdt->GetExternalCovariance(cov);
+ t = new AliExternalTrackParam(x,esdt->GetAlpha(),p,cov);
+ } else if(fMode==1) { // TPC mode
+ t = (AliExternalTrackParam*)esdt->GetTPCInnerParam();
+ if(!t) continue;
+ Double_t radius = 2.8; //something less than the beam pipe radius
+ if(!PropagateTrackTo(t,radius)) continue;
+ }
+ } else { // AOD (only ITS mode)
+ Int_t ncls0=0;
+ for(Int_t l=0;l<6;l++) if(TESTBIT(track->GetITSClusterMap(),l)) ncls0++;
+ if(ncls0 < fMinClusters) continue;
+ t = new AliExternalTrackParam(track);
+ }
+ trkArrayOrig.AddLast(t);
+ idOrig[nTrksOrig]=(UShort_t)track->GetID();
+ nTrksOrig++;
+ } // end loop on tracks
+
+ // call method that will reconstruct the vertex
+ FindPrimaryVertex(&trkArrayOrig,idOrig);
+
+ if(fMode==0) trkArrayOrig.Delete();
+ delete idOrig; idOrig=NULL;
+
+ if(f) {
+ f->Close(); delete f; f = NULL;
+ gSystem->Unlink("VertexerTracks.root");
+ olddir->cd();
+ }
+
+ // set vertex ID for tracks used in the fit
+ // (only for ESD)
+ if(!inputAOD) {
+ Int_t nIndices = fCurrentVertex->GetNIndices();
+ UShort_t *indices = fCurrentVertex->GetIndices();
+ for(Int_t ind=0; ind<nIndices; ind++) {
+ AliESDtrack *esdt = (AliESDtrack*)vEvent->GetTrack(indices[ind]);
+ esdt->SetVertexID(-1);
+ }
+ }
+
+ return fCurrentVertex;
+}
+//----------------------------------------------------------------------------
+AliESDVertex* AliVertexerTracks::FindPrimaryVertex(TObjArray *trkArrayOrig,
+ UShort_t *idOrig)
+{
+//
+// Primary vertex using the AliExternalTrackParam's in the TObjArray.
+// idOrig must contain the track IDs from AliESDtrack::GetID()
+// (Two iterations:
+// 1st with 5*fNSigma*sigma cut w.r.t. to initial vertex
+// + cut on sqrt(d0d0+z0z0) if fConstraint=kFALSE
+// 2nd with fNSigma*sigma cut w.r.t. to vertex found in 1st iteration)
+//
+ fCurrentVertex = 0;
+
+ // accept 1-track case only if constraint is available
+ if(!fConstraint && fMinTracks==1) fMinTracks=2;
+
+ // read tracks from array
+ Int_t nTrksOrig = (Int_t)trkArrayOrig->GetEntriesFast();
+ AliDebug(1,Form("Initial number of tracks: %d",nTrksOrig));
+ if(nTrksOrig<fMinTracks) {
+ AliDebug(1,"TooFewTracks");
+ TooFewTracks();
+ return fCurrentVertex;
+ }
+
+ // If fConstraint=kFALSE
+ // run VertexFinder(1) to get rough estimate of initVertex (x,y)
+ if(!fConstraint) {
+ // fill fTrkArraySel, for VertexFinder()
+ fIdSel = new UShort_t[nTrksOrig];
+ PrepareTracks(*trkArrayOrig,idOrig,0);
+ if(fIdSel) { delete fIdSel; fIdSel=NULL; }
+ Double_t cutsave = fDCAcut;
+ fDCAcut = fDCAcutIter0;
+ // vertex finder
+ switch (fAlgoIter0) {
+ case 1: StrLinVertexFinderMinDist(1); break;
+ case 2: StrLinVertexFinderMinDist(0); break;
+ case 3: HelixVertexFinder(); break;
+ case 4: VertexFinder(1); break;
+ case 5: VertexFinder(0); break;
+ default: printf("Wrong algorithm\n"); break;
+ }
+ fDCAcut = cutsave;
+ if(fVert.GetNContributors()>0) {
+ fVert.GetXYZ(fNominalPos);
+ fNominalPos[0] = fVert.GetXv();
+ fNominalPos[1] = fVert.GetYv();
+ fNominalPos[2] = fVert.GetZv();
+ AliDebug(1,Form("No mean vertex: VertexFinder gives (%f, %f, %f)",fNominalPos[0],fNominalPos[1],fNominalPos[2]));
+ } else {
+ fNominalPos[0] = 0.;
+ fNominalPos[1] = 0.;
+ fNominalPos[2] = 0.;
+ AliDebug(1,"No mean vertex and VertexFinder failed");
+ }
+ }
+
+ // TWO ITERATIONS:
+ //
+ // ITERATION 1
+ // propagate tracks to fNominalPos vertex
+ // preselect them:
+ // if(constraint) reject for |d0|>5*fNSigma*sigma w.r.t. fNominal... vertex
+ // else reject for |d0|\oplus|z0| > 5 mm w.r.t. fNominal... vertex
+ // ITERATION 2
+ // propagate tracks to best between initVertex and fCurrentVertex
+ // preselect tracks (reject for |d0|>fNSigma*sigma w.r.t. best
+ // between initVertex and fCurrentVertex)
+ for(Int_t iter=1; iter<=2; iter++) {
+ if(fOnlyFitter && iter==1) continue;
+ if(fIdSel) { delete fIdSel; fIdSel=NULL; }
+ fIdSel = new UShort_t[nTrksOrig];
+ Int_t nTrksSel = PrepareTracks(*trkArrayOrig,idOrig,iter);
+ AliDebug(1,Form("N tracks selected in iteration %d: %d",iter,nTrksSel));
+ if(nTrksSel < fMinTracks) {
+ TooFewTracks();
+ return fCurrentVertex;
+ }
+
+ // vertex finder
+ if(!fOnlyFitter) {
+ if(nTrksSel==1) {
+ AliDebug(1,"Just one track");
+ OneTrackVertFinder();
+ } else {
+ switch (fAlgo) {
+ case 1: StrLinVertexFinderMinDist(1); break;
+ case 2: StrLinVertexFinderMinDist(0); break;
+ case 3: HelixVertexFinder(); break;
+ case 4: VertexFinder(1); break;
+ case 5: VertexFinder(0); break;
+ default: printf("Wrong algorithm"); break;
+ }
+ }
+ AliDebug(1," Vertex finding completed");
+ }
+
+ // vertex fitter
+ VertexFitter();
+ } // end loop on the two iterations
+
+
+ // set indices of used tracks
+ UShort_t *indices = 0;
+ if(fCurrentVertex->GetNContributors()>0) {
+ Int_t nIndices = (Int_t)fTrkArraySel.GetEntriesFast();
+ indices = new UShort_t[nIndices];
+ for(Int_t jj=0; jj<nIndices; jj++)
+ indices[jj] = fIdSel[jj];
+ fCurrentVertex->SetIndices(nIndices,indices);
+ }
+ if (indices) {delete indices; indices=NULL;}
+ //
+
+ // set vertex title
+ TString title="VertexerTracksNoConstraint";
+ if(fConstraint) {
+ title="VertexerTracksWithConstraint";
+ if(fOnlyFitter) title.Append("OnlyFitter");
+ }
+ fCurrentVertex->SetTitle(title.Data());
+ //
+
+ AliDebug(1,Form("xyz: %f %f %f; nc %d",fCurrentVertex->GetXv(),fCurrentVertex->GetYv(),fCurrentVertex->GetZv(),fCurrentVertex->GetNContributors()));
+
+ // clean up
+ delete fIdSel; fIdSel=NULL;
+ fTrkArraySel.Delete();
+ if(fTrksToSkip) { delete fTrksToSkip; fTrksToSkip=NULL; }
+ //
+
+ return fCurrentVertex;
+}
+//------------------------------------------------------------------------
+Double_t AliVertexerTracks::GetDeterminant3X3(Double_t matr[][3])
+{
+ //
+ Double_t det=matr[0][0]*matr[1][1]*matr[2][2]-matr[0][0]*matr[1][2]*matr[2][1]-matr[0][1]*matr[1][0]*matr[2][2]+matr[0][1]*matr[1][2]*matr[2][0]+matr[0][2]*matr[1][0]*matr[2][1]-matr[0][2]*matr[1][1]*matr[2][0];
+ return det;
+}
+//-------------------------------------------------------------------------
+void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t (*m)[3],Double_t *d)
+{
+ //
+ Double_t x12=p0[0]-p1[0];
+ Double_t y12=p0[1]-p1[1];
+ Double_t z12=p0[2]-p1[2];
+ Double_t kk=x12*x12+y12*y12+z12*z12;
+ m[0][0]=2-2/kk*x12*x12;
+ m[0][1]=-2/kk*x12*y12;
+ m[0][2]=-2/kk*x12*z12;
+ m[1][0]=-2/kk*x12*y12;
+ m[1][1]=2-2/kk*y12*y12;
+ m[1][2]=-2/kk*y12*z12;
+ m[2][0]=-2/kk*x12*z12;
+ m[2][1]=-2*y12*z12;
+ m[2][2]=2-2/kk*z12*z12;
+ d[0]=2*p0[0]-2/kk*p0[0]*x12*x12-2/kk*p0[2]*x12*z12-2/kk*p0[1]*x12*y12;
+ d[1]=2*p0[1]-2/kk*p0[1]*y12*y12-2/kk*p0[0]*x12*y12-2/kk*p0[2]*z12*y12;
+ d[2]=2*p0[2]-2/kk*p0[2]*z12*z12-2/kk*p0[0]*x12*z12-2/kk*p0[1]*z12*y12;
+
+}
+//--------------------------------------------------------------------------
+void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t *sigmasq,Double_t (*m)[3],Double_t *d)
+{
+ //
+ Double_t x12=p1[0]-p0[0];
+ Double_t y12=p1[1]-p0[1];
+ Double_t z12=p1[2]-p0[2];
+
+ Double_t den= x12*x12*sigmasq[1]*sigmasq[2]+y12*y12*sigmasq[0]*sigmasq[2]+z12*z12*sigmasq[0]*sigmasq[1];
+
+ Double_t kk= 2*(x12*x12/sigmasq[0]+y12*y12/sigmasq[1]+z12*z12/sigmasq[2]);
+
+ Double_t cc[3];
+ cc[0]=-x12/sigmasq[0];
+ cc[1]=-y12/sigmasq[1];
+ cc[2]=-z12/sigmasq[2];
+
+ Double_t ww=(-p0[0]*x12*sigmasq[1]*sigmasq[2]-p0[1]*y12*sigmasq[0]*sigmasq[2]-p0[2]*z12*sigmasq[0]*sigmasq[1])/den;
+
+ Double_t ss= -p0[0]*cc[0]-p0[1]*cc[1]-p0[2]*cc[2];
+
+ Double_t aa[3];
+ aa[0]=x12*sigmasq[1]*sigmasq[2]/den;
+ aa[1]=y12*sigmasq[0]*sigmasq[2]/den;
+ aa[2]=z12*sigmasq[0]*sigmasq[1]/den;
+
+ m[0][0]=aa[0]*(aa[0]*kk+2*cc[0])+2*cc[0]*aa[0]+2/sigmasq[0];
+ m[0][1]=aa[1]*(aa[0]*kk+2*cc[0])+2*cc[1]*aa[0];
+ m[0][2]=aa[2]*(aa[0]*kk+2*cc[0])+2*cc[2]*aa[0];
+
+ m[1][0]=aa[0]*(aa[1]*kk+2*cc[1])+2*cc[0]*aa[1];
+ m[1][1]=aa[1]*(aa[1]*kk+2*cc[1])+2*cc[1]*aa[1]+2/sigmasq[1];
+ m[1][2]=aa[2]*(aa[1]*kk+2*cc[1])+2*cc[2]*aa[1];
+
+ m[2][0]=aa[0]*(aa[2]*kk+2*cc[2])+2*cc[0]*aa[2];
+ m[2][1]=aa[1]*(aa[2]*kk+2*cc[2])+2*cc[1]*aa[2];
+ m[2][2]=aa[2]*(aa[2]*kk+2*cc[2])+2*cc[2]*aa[2]+2/sigmasq[2];
+
+ d[0]=-ww*(aa[0]*kk+2*cc[0])-2*ss*aa[0]+2*p0[0]/sigmasq[0];
+ d[1]=-ww*(aa[1]*kk+2*cc[1])-2*ss*aa[1]+2*p0[1]/sigmasq[1];
+ d[2]=-ww*(aa[2]*kk+2*cc[2])-2*ss*aa[2]+2*p0[2]/sigmasq[2];
+
+ }
+//--------------------------------------------------------------------------
+Double_t AliVertexerTracks::GetStrLinMinDist(Double_t *p0,Double_t *p1,Double_t *x0)
+{
+ //
+ Double_t x12=p0[0]-p1[0];
+ Double_t y12=p0[1]-p1[1];
+ Double_t z12=p0[2]-p1[2];
+ Double_t x10=p0[0]-x0[0];
+ Double_t y10=p0[1]-x0[1];
+ Double_t z10=p0[2]-x0[2];
+ // return ((x10*x10+y10*y10+z10*z10)*(x12*x12+y12*y12+z12*z12)-(x10*x12+y10*y12+z10*z12)*(x10*x12+y10*y12+z10*z12))/(x12*x12+y12*y12+z12*z12);
+ return ((y10*z12-z10*y12)*(y10*z12-z10*y12)+
+ (z10*x12-x10*z12)*(z10*x12-x10*z12)+
+ (x10*y12-y10*x12)*(x10*y12-y10*x12))
+ /(x12*x12+y12*y12+z12*z12);
+}
+//---------------------------------------------------------------------------
+void AliVertexerTracks::OneTrackVertFinder()
+{
+ // find vertex for events with 1 track, using DCA to nominal beam axis
+ AliDebug(1,Form("Number of prepared tracks =%d - Call OneTrackVertFinder",fTrkArraySel.GetEntries()));
+ AliExternalTrackParam *track1;
+ track1 = (AliExternalTrackParam*)fTrkArraySel.At(0);
+ Double_t alpha=track1->GetAlpha();
+ Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
+ Double_t pos[3],dir[3];
+ track1->GetXYZAt(mindist,GetFieldkG(),pos);
+ track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
+ AliStrLine *line1 = new AliStrLine(pos,dir);
+ Double_t p1[3]={fNominalPos[0],fNominalPos[1],0.};
+ Double_t p2[3]={fNominalPos[0],fNominalPos[1],10.};
+ AliStrLine *zeta=new AliStrLine(p1,p2,kTRUE);
+ Double_t crosspoint[3]={0.,0.,0.};
+ Double_t sigma=999.;
+ Int_t nContrib=-1;
+ Int_t retcode = zeta->Cross(line1,crosspoint);
+ if(retcode>=0){
+ sigma=line1->GetDistFromPoint(crosspoint);
+ nContrib=1;
+ }
+ delete zeta;
+ delete line1;
+ fVert.SetXYZ(crosspoint);
+ fVert.SetDispersion(sigma);
+ fVert.SetNContributors(nContrib);
+}
+//---------------------------------------------------------------------------
+void AliVertexerTracks::HelixVertexFinder()
+{
+ // Get estimate of vertex position in (x,y) from tracks DCA
+
+
+ Double_t initPos[3];
+ initPos[2] = 0.;
+ for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
+
+ Int_t nacc = (Int_t)fTrkArraySel.GetEntriesFast();
+
+ Double_t aver[3]={0.,0.,0.};
+ Double_t averquad[3]={0.,0.,0.};
+ Double_t sigmaquad[3]={0.,0.,0.};
+ Double_t sigma=0;
+ Int_t ncombi = 0;
+ AliExternalTrackParam *track1;
+ AliExternalTrackParam *track2;
+ Double_t distCA;
+ Double_t x;
+ Double_t alpha, cs, sn;
+ Double_t crosspoint[3];
+ for(Int_t i=0; i<nacc; i++){
+ track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
+
+
+ for(Int_t j=i+1; j<nacc; j++){
+ track2 = (AliExternalTrackParam*)fTrkArraySel.At(j);
+
+ distCA=track2->PropagateToDCA(track1,GetFieldkG());
+ if(fDCAcut<=0 ||(fDCAcut>0&&distCA<fDCAcut)){
+ x=track1->GetX();
+ alpha=track1->GetAlpha();
+ cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
+ Double_t x1=x*cs - track1->GetY()*sn;
+ Double_t y1=x*sn + track1->GetY()*cs;
+ Double_t z1=track1->GetZ();
+
+ Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
+ x=track2->GetX();
+ alpha=track2->GetAlpha();
+ cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
+ Double_t x2=x*cs - track2->GetY()*sn;
+ Double_t y2=x*sn + track2->GetY()*cs;
+ Double_t z2=track2->GetZ();
+ Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
+ Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
+ Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
+ Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
+ Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
+ crosspoint[0]=wx1*x1 + wx2*x2;
+ crosspoint[1]=wy1*y1 + wy2*y2;
+ crosspoint[2]=wz1*z1 + wz2*z2;
+
+ ncombi++;
+ for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
+ for(Int_t jj=0;jj<3;jj++)averquad[jj]+=(crosspoint[jj]*crosspoint[jj]);
+ }
+ }
+
+ }
+ if(ncombi>0){
+ for(Int_t jj=0;jj<3;jj++){
+ initPos[jj] = aver[jj]/ncombi;
+ averquad[jj]/=ncombi;
+ sigmaquad[jj]=averquad[jj]-initPos[jj]*initPos[jj];
+ sigma+=sigmaquad[jj];
+ }
+ sigma=TMath::Sqrt(TMath::Abs(sigma));
+ }
+ else {
+ Warning("HelixVertexFinder","Finder did not succed");
+ sigma=999;
+ }
+ fVert.SetXYZ(initPos);
+ fVert.SetDispersion(sigma);
+ fVert.SetNContributors(ncombi);
+}
+//----------------------------------------------------------------------------
+Int_t AliVertexerTracks::PrepareTracks(TObjArray &trkArrayOrig,
+ UShort_t *idOrig,
+ Int_t optImpParCut)
+{
+//
+// Propagate tracks to initial vertex position and store them in a TObjArray
+//
+ AliDebug(1," PrepareTracks()");
+
+ Int_t nTrksOrig = (Int_t)trkArrayOrig.GetEntriesFast();
+ Int_t nTrksSel = 0;
+ Double_t maxd0rphi;
+ Double_t sigmaCurr[3];
+ Double_t normdistx,normdisty;
+ Double_t d0z0[2],covd0z0[3];
+ Double_t sigmad0;
+
+ AliESDVertex *initVertex = new AliESDVertex(fNominalPos,fNominalCov,1,1);
+
+ if(!fTrkArraySel.IsEmpty()) fTrkArraySel.Delete();
+
+ AliExternalTrackParam *track=0;
+
+ // loop on tracks
+ for(Int_t i=0; i<nTrksOrig; i++) {
+ AliExternalTrackParam *trackOrig=(AliExternalTrackParam*)trkArrayOrig.At(i);
+ if(trackOrig->Charge()!=0) { // normal tracks
+ track = new AliExternalTrackParam(*(AliExternalTrackParam*)trkArrayOrig.At(i));
+ } else { // neutral tracks (from a V0)
+ track = new AliNeutralTrackParam(*(AliNeutralTrackParam*)trkArrayOrig.At(i));
+ }
+
+ // tgl cut
+ if(TMath::Abs(track->GetTgl())>fMaxTgl) {
+ AliDebug(1,Form(" rejecting track with tgl = %f",track->GetTgl()));
+ delete track; continue;
+ }
+
+ Bool_t propagateOK = kFALSE;
+ // propagate track to vertex
+ if(optImpParCut<2 || fOnlyFitter) { // optImpParCut==1 or 0
+ propagateOK = track->PropagateToDCA(initVertex,GetFieldkG(),100.,d0z0,covd0z0);
+ } else { // optImpParCut==2
+ fCurrentVertex->GetSigmaXYZ(sigmaCurr);
+ normdistx = TMath::Abs(fCurrentVertex->GetXv()-fNominalPos[0])/TMath::Sqrt(sigmaCurr[0]*sigmaCurr[0]+fNominalCov[0]);
+ normdisty = TMath::Abs(fCurrentVertex->GetYv()-fNominalPos[1])/TMath::Sqrt(sigmaCurr[1]*sigmaCurr[1]+fNominalCov[2]);
+ if(normdistx < 3. && normdisty < 3. &&
+ (sigmaCurr[0]+sigmaCurr[1])<(TMath::Sqrt(fNominalCov[0])+TMath::Sqrt(fNominalCov[2]))) {
+ propagateOK = track->PropagateToDCA(fCurrentVertex,GetFieldkG(),100.,d0z0,covd0z0);
+ } else {
+ propagateOK = track->PropagateToDCA(initVertex,GetFieldkG(),100.,d0z0,covd0z0);
+ }
+ }
+
+ if(!propagateOK) {
+ AliDebug(1," rejected");
+ delete track; continue;
+ }
+
+ sigmad0 = TMath::Sqrt(covd0z0[0]);
+ maxd0rphi = fNSigma*sigmad0;
+ if(optImpParCut==1) maxd0rphi *= 5.;
+ maxd0rphi = TMath::Min(maxd0rphi,fFiducialR);
+ //sigmad0z0 = TMath::Sqrt(covd0z0[0]+covd0z0[2]); // for future improvement
+ //maxd0z0 = 10.*fNSigma*sigmad0z0;
+
+ AliDebug(1,Form("trk %d; id %d; |d0| = %f; d0 cut = %f; |z0| = %f; |d0|oplus|z0| = %f; d0z0 cut = %f",i,(Int_t)idOrig[i],TMath::Abs(d0z0[0]),maxd0rphi,TMath::Abs(d0z0[1]),TMath::Sqrt(d0z0[0]*d0z0[0]+d0z0[1]*d0z0[1]),fMaxd0z0));
+
+
+ //---- track selection based on impact parameters ----//
+
+ // always reject tracks outside fiducial volume
+ if(TMath::Abs(d0z0[0])>fFiducialR || TMath::Abs(d0z0[1])>fFiducialZ) {
+ AliDebug(1," rejected");
+ delete track; continue;
+ }
+
+ // during iterations 1 and 2 , reject tracks with d0rphi > maxd0rphi
+ if(optImpParCut>0 && TMath::Abs(d0z0[0])>maxd0rphi) {
+ AliDebug(1," rejected");
+ delete track; continue;
+ }
+
+ // if fConstraint=kFALSE, during iterations 1 and 2 ||
+ // if fConstraint=kTRUE, during iteration 2,
+ // select tracks with d0oplusz0 < fMaxd0z0
+ if((!fConstraint && optImpParCut>0 && fVert.GetNContributors()>0) ||
+ ( fConstraint && optImpParCut==2)) {
+ if(nTrksOrig>=3 &&
+ TMath::Sqrt(d0z0[0]*d0z0[0]+d0z0[1]*d0z0[1])>fMaxd0z0) {
+ AliDebug(1," rejected");
+ delete track; continue;
+ }
+ }
+
+ // track passed all selections
+ fTrkArraySel.AddLast(track);
+ fIdSel[nTrksSel] = idOrig[i];
+ nTrksSel++;
+ } // end loop on tracks
+
+ delete initVertex;
+
+ return nTrksSel;
+}
+//----------------------------------------------------------------------------
+Bool_t AliVertexerTracks::PropagateTrackTo(AliExternalTrackParam *track,
+ Double_t xToGo) {
+ //----------------------------------------------------------------
+ // COPIED from AliTracker
+ //
+ // Propagates the track to the plane X=xk (cm).
+ //
+ // Origin: Marian Ivanov, Marian.Ivanov@cern.ch
+ //----------------------------------------------------------------
+
+ const Double_t kEpsilon = 0.00001;
+ Double_t xpos = track->GetX();
+ Double_t dir = (xpos<xToGo) ? 1. : -1.;
+ Double_t maxStep = 5;
+ Double_t maxSnp = 0.8;
+ //
+ while ( (xToGo-xpos)*dir > kEpsilon){
+ Double_t step = dir*TMath::Min(TMath::Abs(xToGo-xpos), maxStep);
+ Double_t x = xpos+step;
+ Double_t xyz0[3],xyz1[3];
+ track->GetXYZ(xyz0); //starting global position
+
+ if(!track->GetXYZAt(x,GetFieldkG(),xyz1)) return kFALSE; // no prolongation
+ xyz1[2]+=kEpsilon; // waiting for bug correction in geo
+
+ if(TMath::Abs(track->GetSnpAt(x,GetFieldkG())) >= maxSnp) return kFALSE;
+ if(!track->PropagateTo(x,GetFieldkG())) return kFALSE;
+
+ if(TMath::Abs(track->GetSnp()) >= maxSnp) return kFALSE;
+ track->GetXYZ(xyz0); // global position
+ Double_t alphan = TMath::ATan2(xyz0[1], xyz0[0]);
+ //
+ Double_t ca=TMath::Cos(alphan-track->GetAlpha()),
+ sa=TMath::Sin(alphan-track->GetAlpha());
+ Double_t sf=track->GetSnp(), cf=TMath::Sqrt((1.-sf)*(1.+sf));
+ Double_t sinNew = sf*ca - cf*sa;
+ if(TMath::Abs(sinNew) >= maxSnp) return kFALSE;
+ if(!track->Rotate(alphan)) return kFALSE;
+
+ xpos = track->GetX();
+ }
+ return kTRUE;
+}
+//---------------------------------------------------------------------------
+AliESDVertex* AliVertexerTracks::RemoveTracksFromVertex(AliESDVertex *inVtx,
+ TObjArray *trkArray,
+ UShort_t *id,
+ Float_t *diamondxy) const
+{
+//
+// Removes tracks in trksTree from fit of inVtx
+//
+
+ if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraint")) {
+ printf("ERROR: primary vertex has no constraint: cannot remove tracks");
+ return 0x0;
+ }
+ if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraintOnlyFitter"))
+ printf("WARNING: result of tracks' removal will be only approximately correct");
+
+ TMatrixD rv(3,1);
+ rv(0,0) = inVtx->GetXv();
+ rv(1,0) = inVtx->GetYv();
+ rv(2,0) = inVtx->GetZv();
+ TMatrixD vV(3,3);
+ Double_t cov[6];
+ inVtx->GetCovMatrix(cov);
+ vV(0,0) = cov[0];
+ vV(0,1) = cov[1]; vV(1,0) = cov[1];
+ vV(1,1) = cov[2];
+ vV(0,2) = cov[3]; vV(2,0) = cov[3];
+ vV(1,2) = cov[4]; vV(2,1) = cov[4];
+ vV(2,2) = cov[5];
+
+ TMatrixD sumWi(TMatrixD::kInverted,vV);
+ TMatrixD sumWiri(sumWi,TMatrixD::kMult,rv);
+
+ Int_t nUsedTrks = inVtx->GetNIndices();
+ Double_t chi2 = inVtx->GetChi2();
+
+ AliExternalTrackParam *track = 0;
+ Int_t ntrks = (Int_t)trkArray->GetEntriesFast();
+ for(Int_t i=0;i<ntrks;i++) {
+ track = (AliExternalTrackParam*)trkArray->At(i);
+ if(!inVtx->UsesTrack(id[i])) {
+ printf("track %d was not used in vertex fit",id[i]);
+ continue;
+ }
+ Double_t alpha = track->GetAlpha();
+ Double_t xl = diamondxy[0]*TMath::Cos(alpha)+diamondxy[1]*TMath::Sin(alpha);
+ track->PropagateTo(xl,GetFieldkG());
+ // vector of track global coordinates
+ TMatrixD ri(3,1);
+ // covariance matrix of ri
+ TMatrixD wWi(3,3);
+
+ // get space point from track
+ if(!TrackToPoint(track,ri,wWi)) continue;
+
+ TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
+
+ sumWi -= wWi;
+ sumWiri -= wWiri;
+
+ // track contribution to chi2
+ TMatrixD deltar = rv; deltar -= ri;
+ TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
+ Double_t chi2i = deltar(0,0)*wWideltar(0,0)+
+ deltar(1,0)*wWideltar(1,0)+
+ deltar(2,0)*wWideltar(2,0);
+ // remove from total chi2
+ chi2 -= chi2i;
+
+ nUsedTrks--;
+ if(nUsedTrks<2) {
+ printf("Trying to remove too many tracks!");
+ return 0x0;
+ }
+ }
+
+ TMatrixD rvnew(3,1);
+ TMatrixD vVnew(3,3);
+
+ // new inverted of weights matrix
+ TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
+ vVnew = invsumWi;
+ // new position of primary vertex
+ rvnew.Mult(vVnew,sumWiri);
+
+ Double_t position[3];
+ position[0] = rvnew(0,0);
+ position[1] = rvnew(1,0);
+ position[2] = rvnew(2,0);
+ cov[0] = vVnew(0,0);
+ cov[1] = vVnew(0,1);
+ cov[2] = vVnew(1,1);
+ cov[3] = vVnew(0,2);
+ cov[4] = vVnew(1,2);
+ cov[5] = vVnew(2,2);
+
+ // store data in the vertex object
+ AliESDVertex *outVtx = new AliESDVertex(position,cov,chi2,nUsedTrks+1); // the +1 is for the constraint
+ outVtx->SetTitle(inVtx->GetTitle());
+ UShort_t *inindices = inVtx->GetIndices();
+ Int_t nIndices = nUsedTrks;
+ UShort_t *outindices = new UShort_t[nIndices];
+ Int_t j=0;
+ for(Int_t k=0; k<inVtx->GetNIndices(); k++) {
+ Bool_t copyindex=kTRUE;
+ for(Int_t l=0; l<ntrks; l++) {
+ if(inindices[k]==id[l]) copyindex=kFALSE;
+ }
+ if(copyindex) {
+ outindices[j] = inindices[k]; j++;
+ }
+ }
+ outVtx->SetIndices(nIndices,outindices);
+ if (outindices) delete outindices;
+
+ /*
+ printf("Vertex before removing tracks:");
+ inVtx->PrintStatus();
+ inVtx->PrintIndices();
+ printf("Vertex after removing tracks:");
+ outVtx->PrintStatus();
+ outVtx->PrintIndices();
+ */
+
+ return outVtx;
+}
+//---------------------------------------------------------------------------
+AliESDVertex* AliVertexerTracks::RemoveConstraintFromVertex(AliESDVertex *inVtx,
+ Float_t *diamondxyz,
+ Float_t *diamondcov) const
+{
+//
+// Removes diamond constraint from fit of inVtx
+//
+
+ if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraint")) {
+ printf("ERROR: primary vertex has no constraint: cannot remove it\n");
+ return 0x0;
+ }
+ if(inVtx->GetNContributors()<3) {
+ printf("ERROR: primary vertex has less than 2 tracks: cannot remove contraint\n");
+ return 0x0;
+ }
+
+ // diamond constraint
+ TMatrixD vVb(3,3);
+ vVb(0,0) = diamondcov[0];
+ vVb(0,1) = diamondcov[1];
+ vVb(0,2) = 0.;
+ vVb(1,0) = diamondcov[1];
+ vVb(1,1) = diamondcov[2];
+ vVb(1,2) = 0.;
+ vVb(2,0) = 0.;
+ vVb(2,1) = 0.;
+ vVb(2,2) = diamondcov[5];
+ TMatrixD vVbInv(TMatrixD::kInverted,vVb);
+ TMatrixD rb(3,1);
+ rb(0,0) = diamondxyz[0];
+ rb(1,0) = diamondxyz[1];
+ rb(2,0) = diamondxyz[2];
+ TMatrixD vVbInvrb(vVbInv,TMatrixD::kMult,rb);
+
+ // input vertex
+ TMatrixD rv(3,1);
+ rv(0,0) = inVtx->GetXv();
+ rv(1,0) = inVtx->GetYv();
+ rv(2,0) = inVtx->GetZv();
+ TMatrixD vV(3,3);
+ Double_t cov[6];
+ inVtx->GetCovMatrix(cov);
+ vV(0,0) = cov[0];
+ vV(0,1) = cov[1]; vV(1,0) = cov[1];
+ vV(1,1) = cov[2];
+ vV(0,2) = cov[3]; vV(2,0) = cov[3];
+ vV(1,2) = cov[4]; vV(2,1) = cov[4];
+ vV(2,2) = cov[5];
+ TMatrixD vVInv(TMatrixD::kInverted,vV);
+ TMatrixD vVInvrv(vVInv,TMatrixD::kMult,rv);
+
+
+ TMatrixD sumWi = vVInv - vVbInv;
+
+
+ TMatrixD sumWiri = vVInvrv - vVbInvrb;
+
+ TMatrixD rvnew(3,1);
+ TMatrixD vVnew(3,3);
+
+ // new inverted of weights matrix
+ TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
+ vVnew = invsumWi;
+ // new position of primary vertex
+ rvnew.Mult(vVnew,sumWiri);
+
+ Double_t position[3];
+ position[0] = rvnew(0,0);
+ position[1] = rvnew(1,0);
+ position[2] = rvnew(2,0);
+ cov[0] = vVnew(0,0);
+ cov[1] = vVnew(0,1);
+ cov[2] = vVnew(1,1);
+ cov[3] = vVnew(0,2);
+ cov[4] = vVnew(1,2);
+ cov[5] = vVnew(2,2);
+
+
+ Double_t chi2 = inVtx->GetChi2();
+
+ // diamond constribution to chi2
+ TMatrixD deltar = rv; deltar -= rb;
+ TMatrixD vVbInvdeltar(vVbInv,TMatrixD::kMult,deltar);
+ Double_t chi2b = deltar(0,0)*vVbInvdeltar(0,0)+
+ deltar(1,0)*vVbInvdeltar(1,0)+
+ deltar(2,0)*vVbInvdeltar(2,0);
+ // remove from total chi2
+ chi2 -= chi2b;
+
+ // store data in the vertex object
+ AliESDVertex *outVtx = new AliESDVertex(position,cov,chi2,inVtx->GetNContributors()-1);
+ outVtx->SetTitle("VertexerTracksNoConstraint");
+ UShort_t *inindices = inVtx->GetIndices();
+ Int_t nIndices = inVtx->GetNIndices();
+ outVtx->SetIndices(nIndices,inindices);
+
+ return outVtx;
+}
+//---------------------------------------------------------------------------
+void AliVertexerTracks::SetCuts(Double_t *cuts)
+{
+//
+// Cut values
+//
+ SetDCAcut(cuts[0]);
+ SetDCAcutIter0(cuts[1]);
+ SetMaxd0z0(cuts[2]);
+ if(fMode==0 && cuts[3]<0) SetITSrefitNotRequired();
+ SetMinClusters((Int_t)(TMath::Abs(cuts[3])));
+ SetMinTracks((Int_t)(cuts[4]));
+ SetNSigmad0(cuts[5]);
+ SetMinDetFitter(cuts[6]);
+ SetMaxTgl(cuts[7]);
+ SetFiducialRZ(cuts[8],cuts[9]);
+ fAlgo=(Int_t)(cuts[10]);
+ fAlgoIter0=(Int_t)(cuts[11]);
+
+ return;
+}
+//---------------------------------------------------------------------------
+void AliVertexerTracks::SetITSMode(Double_t dcacut,
+ Double_t dcacutIter0,
+ Double_t maxd0z0,
+ Int_t minCls,
+ Int_t mintrks,
+ Double_t nsigma,
+ Double_t mindetfitter,
+ Double_t maxtgl,
+ Double_t fidR,
+ Double_t fidZ,
+ Int_t finderAlgo,
+ Int_t finderAlgoIter0)
+{
+//
+// Cut values for ITS mode
+//
+ fMode = 0;
+ if(minCls>0) {
+ SetITSrefitRequired();
+ } else {
+ SetITSrefitNotRequired();
+ }
+ SetDCAcut(dcacut);
+ SetDCAcutIter0(dcacutIter0);
+ SetMaxd0z0(maxd0z0);
+ SetMinClusters(TMath::Abs(minCls));
+ SetMinTracks(mintrks);
+ SetNSigmad0(nsigma);
+ SetMinDetFitter(mindetfitter);
+ SetMaxTgl(maxtgl);
+ SetFiducialRZ(fidR,fidZ);
+ fAlgo=finderAlgo;
+ fAlgoIter0=finderAlgoIter0;
+
+ return;
+}
+//---------------------------------------------------------------------------
+void AliVertexerTracks::SetTPCMode(Double_t dcacut,
+ Double_t dcacutIter0,
+ Double_t maxd0z0,
+ Int_t minCls,
+ Int_t mintrks,
+ Double_t nsigma,
+ Double_t mindetfitter,
+ Double_t maxtgl,
+ Double_t fidR,
+ Double_t fidZ,
+ Int_t finderAlgo,
+ Int_t finderAlgoIter0)
+{
+//
+// Cut values for TPC mode
+//
+ fMode = 1;
+ SetITSrefitNotRequired();
+ SetDCAcut(dcacut);
+ SetDCAcutIter0(dcacutIter0);
+ SetMaxd0z0(maxd0z0);
+ SetMinClusters(minCls);
+ SetMinTracks(mintrks);
+ SetNSigmad0(nsigma);
+ SetMinDetFitter(mindetfitter);
+ SetMaxTgl(maxtgl);
+ SetFiducialRZ(fidR,fidZ);
+ fAlgo=finderAlgo;
+ fAlgoIter0=finderAlgoIter0;
+
+ return;
+}
+//---------------------------------------------------------------------------
+void AliVertexerTracks::SetSkipTracks(Int_t n,Int_t *skipped)
+{
+//
+// Mark the tracks not to be used in the vertex reconstruction.
+// Tracks are identified by AliESDtrack::GetID()
+//
+ fNTrksToSkip = n; fTrksToSkip = new Int_t[n];
+ for(Int_t i=0;i<n;i++) fTrksToSkip[i] = skipped[i];
+ return;
+}
+//---------------------------------------------------------------------------
+void AliVertexerTracks::SetVtxStart(AliESDVertex *vtx)
+{
+//
+// Set initial vertex knowledge
+//
+ vtx->GetXYZ(fNominalPos);
+ vtx->GetCovMatrix(fNominalCov);
+ SetConstraintOn();
+ return;
+}
+//---------------------------------------------------------------------------
+void AliVertexerTracks::StrLinVertexFinderMinDist(Int_t optUseWeights)
+{
+ AliExternalTrackParam *track1;
+ const Int_t knacc = (Int_t)fTrkArraySel.GetEntriesFast();
+ AliStrLine **linarray = new AliStrLine* [knacc];
+ for(Int_t i=0; i<knacc; i++){
+ track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
+ Double_t alpha=track1->GetAlpha();
+ Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
+ Double_t pos[3],dir[3],sigmasq[3];
+ track1->GetXYZAt(mindist,GetFieldkG(),pos);
+ track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
+ sigmasq[0]=TMath::Sin(alpha)*TMath::Sin(alpha)*track1->GetSigmaY2();
+ sigmasq[1]=TMath::Cos(alpha)*TMath::Cos(alpha)*track1->GetSigmaY2();
+ sigmasq[2]=track1->GetSigmaZ2();
+ TMatrixD ri(3,1);
+ TMatrixD wWi(3,3);
+ if(!TrackToPoint(track1,ri,wWi)) {optUseWeights=kFALSE;printf("WARNING\n");}
+ Double_t wmat[9];
+ Int_t iel=0;
+ for(Int_t ia=0;ia<3;ia++){
+ for(Int_t ib=0;ib<3;ib++){
+ wmat[iel]=wWi(ia,ib);
+ iel++;
+ }
+ }
+ linarray[i] = new AliStrLine(pos,sigmasq,wmat,dir);
+ }
+ fVert=TrackletVertexFinder(linarray,knacc,optUseWeights);
+ for(Int_t i=0; i<knacc; i++) delete linarray[i];
+ delete [] linarray;
+}
+//---------------------------------------------------------------------------
+AliESDVertex AliVertexerTracks::TrackletVertexFinder(TClonesArray *lines, Int_t optUseWeights)
+{
+ // Calculate the point at minimum distance to prepared tracks (TClonesArray)
+ const Int_t knacc = (Int_t)lines->GetEntriesFast();
+ AliStrLine** lines2 = new AliStrLine* [knacc];
+ for(Int_t i=0; i<knacc; i++){
+ lines2[i]= (AliStrLine*)lines->At(i);
+ }
+ AliESDVertex vert = TrackletVertexFinder(lines2,knacc,optUseWeights);
+ delete [] lines2;
+ return vert;
+}
+
+//---------------------------------------------------------------------------
+AliESDVertex AliVertexerTracks::TrackletVertexFinder(AliStrLine **lines, const Int_t knacc, Int_t optUseWeights)
+{
+ // Calculate the point at minimum distance to prepared tracks (array of AliStrLine)
+
+ Double_t initPos[3]={0.,0.,0.};
+
+ Double_t (*vectP0)[3]=new Double_t [knacc][3];
+ Double_t (*vectP1)[3]=new Double_t [knacc][3];
+
+ Double_t sum[3][3];
+ Double_t dsum[3]={0,0,0};
+ TMatrixD sumWi(3,3);
+ for(Int_t i=0;i<3;i++){
+ for(Int_t j=0;j<3;j++){
+ sum[i][j]=0;
+ sumWi(i,j)=0.;
+ }
+ }
+
+ for(Int_t i=0; i<knacc; i++){
+ AliStrLine *line1 = lines[i];
+ Double_t p0[3],cd[3],sigmasq[3];
+ Double_t wmat[9];
+ if(!line1) printf("ERROR %d %d\n",i,knacc);
+ line1->GetP0(p0);
+ line1->GetCd(cd);
+ line1->GetSigma2P0(sigmasq);
+ line1->GetWMatrix(wmat);
+ TMatrixD wWi(3,3);
+ Int_t iel=0;
+ for(Int_t ia=0;ia<3;ia++){
+ for(Int_t ib=0;ib<3;ib++){
+ wWi(ia,ib)=wmat[iel];
+ iel++;
+ }
+ }
+
+ sumWi+=wWi;
+
+ Double_t p1[3]={p0[0]+cd[0],p0[1]+cd[1],p0[2]+cd[2]};
+ vectP0[i][0]=p0[0];
+ vectP0[i][1]=p0[1];
+ vectP0[i][2]=p0[2];
+ vectP1[i][0]=p1[0];
+ vectP1[i][1]=p1[1];
+ vectP1[i][2]=p1[2];
+
+ Double_t matr[3][3];
+ Double_t dknow[3];
+ if(optUseWeights==0)GetStrLinDerivMatrix(p0,p1,matr,dknow);
+ else GetStrLinDerivMatrix(p0,p1,sigmasq,matr,dknow);
+
+
+ for(Int_t iii=0;iii<3;iii++){
+ dsum[iii]+=dknow[iii];
+ for(Int_t lj=0;lj<3;lj++) sum[iii][lj]+=matr[iii][lj];
+ }
+ }
+
+ TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
+ Double_t covmatrix[6];
+ covmatrix[0] = invsumWi(0,0);
+ covmatrix[1] = invsumWi(0,1);
+ covmatrix[2] = invsumWi(1,1);
+ covmatrix[3] = invsumWi(0,2);
+ covmatrix[4] = invsumWi(1,2);
+ covmatrix[5] = invsumWi(2,2);
+
+ Double_t vett[3][3];
+ Double_t det=GetDeterminant3X3(sum);
+ Double_t sigma=0;
+
+ if(det!=0){
+ for(Int_t zz=0;zz<3;zz++){
+ for(Int_t ww=0;ww<3;ww++){
+ for(Int_t kk=0;kk<3;kk++) vett[ww][kk]=sum[ww][kk];
+ }
+ for(Int_t kk=0;kk<3;kk++) vett[kk][zz]=dsum[kk];
+ initPos[zz]=GetDeterminant3X3(vett)/det;
+ }