1 /**************************************************************************
2 * Copyright(c) 1998-2003, ALICE Experiment at CERN, All rights reserved. *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
7 * Permission to use, copy, modify and distribute this software and its *
8 * documentation strictly for non-commercial purposes is hereby granted *
9 * without fee, provided that the above copyright notice appears in all *
10 * copies and that both the copyright notice and this permission notice *
11 * appear in the supporting documentation. The authors make no claims *
12 * about the suitability of this software for any purpose. It is *
13 * provided "as is" without express or implied warranty. *
14 **************************************************************************/
16 //-----------------------------------------------------------------
17 // Implementation of the vertexer from ESD tracks
19 // Origin: AliITSVertexerTracks
21 // andrea.dainese@pd.infn.it
23 // massimo.masera@to.infn.it
24 // Moved to STEER and adapted to ESD tracks:
25 // F.Prino, Torino, prino@to.infn.it
26 //-----------------------------------------------------------------
28 //---- Root headers --------
31 //---- AliRoot headers -----
32 #include "AliStrLine.h"
33 #include "AliVertexerTracks.h"
35 #include "AliESDtrack.h"
37 ClassImp(AliVertexerTracks)
40 //----------------------------------------------------------------------------
41 AliVertexerTracks::AliVertexerTracks():
62 // Default constructor
71 //----------------------------------------------------------------------------
72 AliVertexerTracks::AliVertexerTracks(Double_t fieldkG):
93 // Standard constructor
103 //-----------------------------------------------------------------------------
104 AliVertexerTracks::~AliVertexerTracks()
106 // Default Destructor
107 // The objects pointed by the following pointer are not owned
108 // by this class and are not deleted
110 if(fTrksToSkip) { delete [] fTrksToSkip; fTrksToSkip=NULL; }
112 //----------------------------------------------------------------------------
113 AliESDVertex* AliVertexerTracks::FindPrimaryVertex(const AliESD *esdEvent)
116 // Primary vertex for current ESD event
118 // 1st with 5*fNSigma*sigma cut w.r.t. to initial vertex
119 // + cut on sqrt(d0d0+z0z0) if fConstraint=kFALSE
120 // 2nd with fNSigma*sigma cut w.r.t. to vertex found in 1st iteration)
121 // All ESD tracks with inside the beam pipe are then propagated to found vertex
125 // accept 1-track case only if constraint is available
126 if(!fConstraint && fMinTracks==1) fMinTracks=2;
128 // read tracks from ESD
129 Int_t nTrksTot = (Int_t)esdEvent->GetNumberOfTracks();
131 if(fDebug) printf("TooFewTracks\n");
132 TooFewTracks(esdEvent);
133 return fCurrentVertex;
136 TTree *trkTree = new TTree("TreeT","tracks");
137 AliESDtrack *esdTrack = 0;
138 trkTree->Branch("tracks","AliESDtrack",&esdTrack);
141 for(Int_t i=0; i<nTrksTot; i++) {
142 AliESDtrack *et = esdEvent->GetTrack(i);
143 esdTrack = new AliESDtrack(*et);
144 // check tracks to skip
146 for(Int_t j=0; j<fNTrksToSkip; j++) {
147 if(et->GetID()==fTrksToSkip[j]) {
148 if(fDebug) printf("skipping track: %d\n",i);
152 if(skipThis) {delete esdTrack;continue;}
154 if(!(esdTrack->GetStatus()&AliESDtrack::kITSin)) {delete esdTrack;continue;}
155 if(fITSrefit && !(esdTrack->GetStatus()&AliESDtrack::kITSrefit)) {delete esdTrack;continue;}
156 Int_t nclus=esdTrack->GetNcls(0); // check number of clusters in ITS
157 if(nclus<fMinITSClusters) {delete esdTrack;continue;}
163 // If fConstraint=kFALSE
164 // run VertexFinder(1) to get rough estimate of initVertex (x,y)
166 // fill fTrkArray, for VertexFinder()
167 if(!fTrkArray.IsEmpty()) fTrkArray.Delete();
168 PrepareTracks(*trkTree,0);
169 Double_t cutsave = fDCAcut; fDCAcut = 0.1; // 1 mm
170 VertexFinder(1); // using weights, cutting dca < fDCAcut
173 if(fVert.GetNContributors()>0) {
174 fVert.GetXYZ(fNominalPos);
175 fNominalPos[0] = fVert.GetXv();
176 fNominalPos[1] = fVert.GetYv();
177 fNominalPos[2] = fVert.GetZv();
178 if(fDebug) printf("No mean vertex: VertexFinder gives (%f, %f, %f)\n",fNominalPos[0],fNominalPos[1],fNominalPos[2]);
183 if(fDebug) printf("No mean vertex and VertexFinder failed\n");
190 // propagate tracks to fNominalPos vertex
192 // if(constraint) reject for |d0|>5*fNSigma*sigma w.r.t. fNominal... vertex
193 // else reject for |d0|\oplus|z0| > 5 mm w.r.t. fNominal... vertex
195 // propagate tracks to best between initVertex and fCurrentVertex
196 // preselect tracks (reject for |d0|>fNSigma*sigma w.r.t. best
197 // between initVertex and fCurrentVertex)
198 for(Int_t iter=0; iter<2; iter++) {
199 if(fOnlyFitter && iter==0) continue;
200 Int_t nTrksPrep = PrepareTracks(*trkTree,iter+1);
201 if(fDebug) printf(" tracks prepared - iteration %d: %d\n",iter+1,nTrksPrep);
202 if(nTrksPrep < fMinTracks) {
203 if(fDebug) printf("TooFewTracks\n");
204 TooFewTracks(esdEvent);
205 if(fDebug) fCurrentVertex->PrintStatus();
208 return fCurrentVertex;
214 if(fDebug) printf("Just one track\n");
215 OneTrackVertFinder();
218 case 1: StrLinVertexFinderMinDist(1); break;
219 case 2: StrLinVertexFinderMinDist(0); break;
220 case 3: HelixVertexFinder(); break;
221 case 4: VertexFinder(1); break;
222 case 5: VertexFinder(0); break;
223 default: printf("Wrong algorithm\n"); break;
226 if(fDebug) printf(" Vertex finding completed\n");
230 VertexFitter(fConstraint);
231 if(fDebug) printf(" Vertex fit completed\n");
232 if(iter==0) fTrkArray.Delete();
233 } // end loop on the two iterations
236 // take true pos from SPD vertex in ESD and write it in tracks' vertex
238 esdEvent->GetVertex()->GetTruePos(tp);
239 fCurrentVertex->SetTruePos(tp);
243 fCurrentVertex->SetTitle("VertexerTracksWithConstraintOnlyFitter");
245 fCurrentVertex->SetTitle("VertexerTracksWithConstraint");
248 fCurrentVertex->SetTitle("VertexerTracksNoConstraint");
252 // set indices of used tracks
253 UShort_t *indices = 0;
254 AliESDtrack *ett = 0;
255 if(fCurrentVertex->GetNContributors()>0) {
256 indices = new UShort_t[fCurrentVertex->GetNContributors()];
257 for(Int_t jj=0;jj<(Int_t)fTrkArray.GetEntriesFast();jj++) {
258 ett = (AliESDtrack*)fTrkArray.At(jj);
259 indices[jj] = (UShort_t)ett->GetID();
261 fCurrentVertex->SetIndices(fCurrentVertex->GetNContributors(),indices);
269 if(fTrksToSkip) { delete [] fTrksToSkip; fTrksToSkip=NULL; }
272 if(fDebug) fCurrentVertex->PrintStatus();
273 if(fDebug) fCurrentVertex->PrintIndices();
276 return fCurrentVertex;
278 //------------------------------------------------------------------------
279 Double_t AliVertexerTracks::GetDeterminant3X3(Double_t matr[][3])
282 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];
285 //-------------------------------------------------------------------------
286 void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t (*m)[3],Double_t *d)
289 Double_t x12=p0[0]-p1[0];
290 Double_t y12=p0[1]-p1[1];
291 Double_t z12=p0[2]-p1[2];
292 Double_t kk=x12*x12+y12*y12+z12*z12;
293 m[0][0]=2-2/kk*x12*x12;
294 m[0][1]=-2/kk*x12*y12;
295 m[0][2]=-2/kk*x12*z12;
296 m[1][0]=-2/kk*x12*y12;
297 m[1][1]=2-2/kk*y12*y12;
298 m[1][2]=-2/kk*y12*z12;
299 m[2][0]=-2/kk*x12*z12;
301 m[2][2]=2-2/kk*z12*z12;
302 d[0]=2*p0[0]-2/kk*p0[0]*x12*x12-2/kk*p0[2]*x12*z12-2/kk*p0[1]*x12*y12;
303 d[1]=2*p0[1]-2/kk*p0[1]*y12*y12-2/kk*p0[0]*x12*y12-2/kk*p0[2]*z12*y12;
304 d[2]=2*p0[2]-2/kk*p0[2]*z12*z12-2/kk*p0[0]*x12*z12-2/kk*p0[1]*z12*y12;
307 //--------------------------------------------------------------------------
308 void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t *sigmasq,Double_t (*m)[3],Double_t *d)
311 Double_t x12=p1[0]-p0[0];
312 Double_t y12=p1[1]-p0[1];
313 Double_t z12=p1[2]-p0[2];
315 Double_t den= x12*x12*sigmasq[1]*sigmasq[2]+y12*y12*sigmasq[0]*sigmasq[2]+z12*z12*sigmasq[0]*sigmasq[1];
317 Double_t kk= 2*(x12*x12/sigmasq[0]+y12*y12/sigmasq[1]+z12*z12/sigmasq[2]);
320 cc[0]=-x12/sigmasq[0];
321 cc[1]=-y12/sigmasq[1];
322 cc[2]=-z12/sigmasq[2];
324 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;
326 Double_t ss= -p0[0]*cc[0]-p0[1]*cc[1]-p0[2]*cc[2];
329 aa[0]=x12*sigmasq[1]*sigmasq[2]/den;
330 aa[1]=y12*sigmasq[0]*sigmasq[2]/den;
331 aa[2]=z12*sigmasq[0]*sigmasq[1]/den;
333 m[0][0]=aa[0]*(aa[0]*kk+2*cc[0])+2*cc[0]*aa[0]+2/sigmasq[0];
334 m[0][1]=aa[1]*(aa[0]*kk+2*cc[0])+2*cc[1]*aa[0];
335 m[0][2]=aa[2]*(aa[0]*kk+2*cc[0])+2*cc[2]*aa[0];
337 m[1][0]=aa[0]*(aa[1]*kk+2*cc[1])+2*cc[0]*aa[1];
338 m[1][1]=aa[1]*(aa[1]*kk+2*cc[1])+2*cc[1]*aa[1]+2/sigmasq[1];
339 m[1][2]=aa[2]*(aa[1]*kk+2*cc[1])+2*cc[2]*aa[1];
341 m[2][0]=aa[0]*(aa[2]*kk+2*cc[2])+2*cc[0]*aa[2];
342 m[2][1]=aa[1]*(aa[2]*kk+2*cc[2])+2*cc[1]*aa[2];
343 m[2][2]=aa[2]*(aa[2]*kk+2*cc[2])+2*cc[2]*aa[2]+2/sigmasq[2];
345 d[0]=-ww*(aa[0]*kk+2*cc[0])-2*ss*aa[0]+2*p0[0]/sigmasq[0];
346 d[1]=-ww*(aa[1]*kk+2*cc[1])-2*ss*aa[1]+2*p0[1]/sigmasq[1];
347 d[2]=-ww*(aa[2]*kk+2*cc[2])-2*ss*aa[2]+2*p0[2]/sigmasq[2];
350 //--------------------------------------------------------------------------
351 Double_t AliVertexerTracks::GetStrLinMinDist(Double_t *p0,Double_t *p1,Double_t *x0)
354 Double_t x12=p0[0]-p1[0];
355 Double_t y12=p0[1]-p1[1];
356 Double_t z12=p0[2]-p1[2];
357 Double_t x10=p0[0]-x0[0];
358 Double_t y10=p0[1]-x0[1];
359 Double_t z10=p0[2]-x0[2];
360 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);
362 //---------------------------------------------------------------------------
363 void AliVertexerTracks::OneTrackVertFinder()
365 // find vertex for events with 1 track, using DCA to nominal beam axis
366 if(fDebug) printf("Number of prepared tracks =%d - Call OneTrackVertFinder",fTrkArray.GetEntries());
368 track1 = (AliESDtrack*)fTrkArray.At(0);
369 Double_t field=GetFieldkG();
370 Double_t alpha=track1->GetAlpha();
371 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
372 Double_t pos[3],dir[3];
373 track1->GetXYZAt(mindist,field,pos);
374 track1->GetPxPyPzAt(mindist,field,dir);
375 AliStrLine *line1 = new AliStrLine(pos,dir);
376 Double_t p1[3]={fNominalPos[0],fNominalPos[1],0.};
377 Double_t p2[3]={fNominalPos[0],fNominalPos[1],10.};
378 AliStrLine *zeta=new AliStrLine(p1,p2,kTRUE);
379 Double_t crosspoint[3]={0.,0.,0.};
382 Int_t retcode = zeta->Cross(line1,crosspoint);
384 sigma=line1->GetDistFromPoint(crosspoint);
389 fVert.SetXYZ(crosspoint);
390 fVert.SetDispersion(sigma);
391 fVert.SetNContributors(nContrib);
393 //---------------------------------------------------------------------------
394 void AliVertexerTracks::HelixVertexFinder()
396 // Get estimate of vertex position in (x,y) from tracks DCA
401 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
402 Double_t field=GetFieldkG();
404 Int_t nacc = (Int_t)fTrkArray.GetEntriesFast();
406 Double_t aver[3]={0.,0.,0.};
407 Double_t averquad[3]={0.,0.,0.};
408 Double_t sigmaquad[3]={0.,0.,0.};
415 Double_t alpha, cs, sn;
416 Double_t crosspoint[3];
417 for(Int_t i=0; i<nacc; i++){
418 track1 = (AliESDtrack*)fTrkArray.At(i);
421 for(Int_t j=i+1; j<nacc; j++){
422 track2 = (AliESDtrack*)fTrkArray.At(j);
424 distCA=track2->PropagateToDCA(track1,field);
425 if(fDCAcut<=0 ||(fDCAcut>0&&distCA<fDCAcut)){
426 track1->GetExternalParameters(x,par);
427 alpha=track1->GetAlpha();
428 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
429 Double_t x1=x*cs - par[0]*sn;
430 Double_t y1=x*sn + par[0]*cs;
432 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
433 track2->GetExternalParameters(x,par);
434 alpha=track2->GetAlpha();
435 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
436 Double_t x2=x*cs - par[0]*sn;
437 Double_t y2=x*sn + par[0]*cs;
439 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
440 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
441 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
442 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
443 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
444 crosspoint[0]=wx1*x1 + wx2*x2;
445 crosspoint[1]=wy1*y1 + wy2*y2;
446 crosspoint[2]=wz1*z1 + wz2*z2;
449 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
450 for(Int_t jj=0;jj<3;jj++)averquad[jj]+=(crosspoint[jj]*crosspoint[jj]);
456 for(Int_t jj=0;jj<3;jj++){
457 initPos[jj] = aver[jj]/ncombi;
458 averquad[jj]/=ncombi;
459 sigmaquad[jj]=averquad[jj]-initPos[jj]*initPos[jj];
460 sigma+=sigmaquad[jj];
462 sigma=TMath::Sqrt(TMath::Abs(sigma));
465 Warning("HelixVertexFinder","Finder did not succed");
468 fVert.SetXYZ(initPos);
469 fVert.SetDispersion(sigma);
470 fVert.SetNContributors(ncombi);
472 //----------------------------------------------------------------------------
473 Int_t AliVertexerTracks::PrepareTracks(TTree &trkTree,Int_t optImpParCut)
476 // Propagate tracks to initial vertex position and store them in a TObjArray
479 Double_t maxd0z0 = fMaxd0z0; // default is 5 mm
481 Double_t sigmaCurr[3];
482 Double_t normdistx,normdisty;
483 Float_t d0z0[2],covd0z0[3];
485 Double_t field=GetFieldkG();
487 AliESDVertex *initVertex = new AliESDVertex(fNominalPos,fNominalCov,1,1);
489 Int_t nEntries = (Int_t)trkTree.GetEntries();
490 if(!fTrkArray.IsEmpty()) fTrkArray.Delete();
493 printf(" PrepareTracks()\n");
496 for(Int_t i=0; i<nEntries; i++) {
497 AliESDtrack *track = new AliESDtrack;
498 trkTree.SetBranchAddress("tracks",&track);
501 // propagate track to vertex
502 if(optImpParCut<=1 || fOnlyFitter) { // optImpParCut==1 or 0
503 track->RelateToVertex(initVertex,field,100.);
504 } else { // optImpParCut==2
505 fCurrentVertex->GetSigmaXYZ(sigmaCurr);
506 normdistx = TMath::Abs(fCurrentVertex->GetXv()-fNominalPos[0])/TMath::Sqrt(sigmaCurr[0]*sigmaCurr[0]+fNominalCov[0]);
507 normdisty = TMath::Abs(fCurrentVertex->GetYv()-fNominalPos[1])/TMath::Sqrt(sigmaCurr[1]*sigmaCurr[1]+fNominalCov[2]);
508 if(normdistx < 3. && normdisty < 3. &&
509 (sigmaCurr[0]+sigmaCurr[1])<(TMath::Sqrt(fNominalCov[0])+TMath::Sqrt(fNominalCov[2]))) {
510 track->RelateToVertex(fCurrentVertex,field,100.);
512 track->RelateToVertex(initVertex,field,100.);
516 track->GetImpactParameters(d0z0,covd0z0);
517 sigma = TMath::Sqrt(covd0z0[0]);
518 maxd0rphi = fNSigma*sigma;
519 if(optImpParCut==1) maxd0rphi *= 5.;
523 if(fDebug) printf("trk %d; lab %d; |d0| = %f; d0 cut = %f; |z0| = %f; |d0|oplus|z0| = %f; d0z0 cut = %f\n",i,track->GetLabel(),TMath::Abs(d0z0[0]),maxd0rphi,TMath::Abs(d0z0[1]),TMath::Sqrt(d0z0[0]*d0z0[0]+d0z0[1]*d0z0[1]),maxd0z0);
525 // during iterations 1 and 2, if fConstraint=kFALSE,
526 // select tracks with d0oplusz0 < maxd0z0
527 if(optImpParCut>=1 && !fConstraint && nEntries>=3 &&
528 fVert.GetNContributors()>0) {
529 if(TMath::Sqrt(d0z0[0]*d0z0[0]+d0z0[1]*d0z0[1]) > maxd0z0) {
530 if(fDebug) printf(" rejected\n");
531 delete track; continue;
535 // select tracks with d0rphi < maxd0rphi
536 if(optImpParCut>0 && TMath::Abs(d0z0[0]) > maxd0rphi) {
537 if(fDebug) printf(" rejected\n");
538 delete track; continue;
541 fTrkArray.AddLast(track);
549 //---------------------------------------------------------------------------
550 AliESDVertex* AliVertexerTracks::RemoveTracksFromVertex(AliESDVertex *inVtx,
555 // Removes tracks in trksTree from fit of inVtx
558 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraint")) {
559 printf("ERROR: primary vertex has no constraint: cannot remove tracks\n");
562 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraintOnlyFitter"))
563 printf("WARNING: result of tracks' removal will be only approximately correct\n");
566 rv(0,0) = inVtx->GetXv();
567 rv(1,0) = inVtx->GetYv();
568 rv(2,0) = inVtx->GetZv();
571 inVtx->GetCovMatrix(cov);
573 vV(0,1) = cov[1]; vV(1,0) = cov[1];
575 vV(0,2) = cov[3]; vV(2,0) = cov[3];
576 vV(1,2) = cov[4]; vV(2,1) = cov[4];
579 TMatrixD sumWi(TMatrixD::kInverted,vV);
580 TMatrixD sumWiri(sumWi,TMatrixD::kMult,rv);
582 Int_t nUsedTrks = inVtx->GetNContributors();
583 Double_t chi2 = inVtx->GetChi2();
585 AliESDtrack *track = 0;
586 trksTree->SetBranchAddress("tracks",&track);
587 Int_t ntrks = trksTree->GetEntries();
588 for(Int_t i=0;i<ntrks;i++) {
589 trksTree->GetEvent(i);
590 if(!inVtx->UsesTrack(track->GetID())) {
591 printf("track %d was not used in vertex fit\n",track->GetID());
594 Double_t alpha = track->GetAlpha();
595 Double_t xl = diamondxy[0]*TMath::Cos(alpha)+diamondxy[1]*TMath::Sin(alpha);
596 track->AliExternalTrackParam::PropagateTo(xl,GetFieldkG());
597 // vector of track global coordinates
599 // covariance matrix of ri
602 // get space point from track
603 if(!TrackToPoint(track,ri,wWi)) continue;
605 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
611 TMatrixD deltar = rv; deltar -= ri;
612 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
613 Double_t chi2i = deltar(0,0)*wWideltar(0,0)+
614 deltar(1,0)*wWideltar(1,0)+
615 deltar(2,0)*wWideltar(2,0);
616 // remove from total chi2
621 printf("Trying to remove too many tracks!\n");
629 // new inverted of weights matrix
630 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
632 // new position of primary vertex
633 rvnew.Mult(vVnew,sumWiri);
635 Double_t position[3];
636 position[0] = rvnew(0,0);
637 position[1] = rvnew(1,0);
638 position[2] = rvnew(2,0);
646 // store data in the vertex object
647 AliESDVertex *outVtx = new AliESDVertex(position,cov,chi2,nUsedTrks);
648 outVtx->SetTitle(inVtx->GetTitle());
650 inVtx->GetTruePos(tp);
651 outVtx->SetTruePos(tp);
652 UShort_t *inindices = inVtx->GetIndices();
653 UShort_t *outindices = new UShort_t[outVtx->GetNContributors()];
656 for(Int_t k=0; k<inVtx->GetNIndices(); k++) {
658 for(Int_t l=0; l<ntrks; l++) {
659 trksTree->GetEvent(l);
660 if(inindices[k]==track->GetID()) copyindex=kFALSE;
663 outindices[j] = inindices[k]; j++;
666 outVtx->SetIndices(outVtx->GetNContributors(),outindices);
667 delete [] outindices;
670 printf("Vertex before removing tracks:\n");
671 inVtx->PrintStatus();
672 inVtx->PrintIndices();
673 printf("Vertex after removing tracks:\n");
674 outVtx->PrintStatus();
675 outVtx->PrintIndices();
680 //---------------------------------------------------------------------------
681 void AliVertexerTracks::SetSkipTracks(Int_t n,Int_t *skipped)
684 // Mark the tracks not to be used in the vertex reconstruction.
685 // Tracks are identified by AliESDtrack::GetID()
687 fNTrksToSkip = n; fTrksToSkip = new Int_t[n];
688 for(Int_t i=0;i<n;i++) fTrksToSkip[i] = skipped[i];
691 //---------------------------------------------------------------------------
692 void AliVertexerTracks::SetVtxStart(AliESDVertex *vtx)
695 // Set initial vertex knowledge
697 vtx->GetXYZ(fNominalPos);
698 vtx->GetCovMatrix(fNominalCov);
702 //---------------------------------------------------------------------------
703 void AliVertexerTracks::StrLinVertexFinderMinDist(Int_t optUseWeights)
706 Double_t field=GetFieldkG();
707 const Int_t knacc = (Int_t)fTrkArray.GetEntriesFast();
708 TClonesArray *linarray = new TClonesArray("AliStrLine",1000);
709 TClonesArray &lines = *linarray;
710 for(Int_t i=0; i<knacc; i++){
711 track1 = (AliESDtrack*)fTrkArray.At(i);
712 Double_t alpha=track1->GetAlpha();
713 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
714 Double_t pos[3],dir[3],sigmasq[3];
715 track1->GetXYZAt(mindist,field,pos);
716 track1->GetPxPyPzAt(mindist,field,dir);
717 sigmasq[0]=TMath::Sin(alpha)*TMath::Sin(alpha)*track1->GetSigmaY2();
718 sigmasq[1]=TMath::Cos(alpha)*TMath::Cos(alpha)*track1->GetSigmaY2();
719 sigmasq[2]=track1->GetSigmaZ2();
722 if(!TrackToPoint(track1,ri,wWi)) continue;
725 for(Int_t ia=0;ia<3;ia++){
726 for(Int_t ib=0;ib<3;ib++){
727 wmat[iel]=wWi(ia,ib);
731 new(lines[i]) AliStrLine(pos,sigmasq,wmat,dir);
733 fVert=TrackletVertexFinder(linarray,optUseWeights);
737 //---------------------------------------------------------------------------
738 AliESDVertex AliVertexerTracks::TrackletVertexFinder(TClonesArray *lines, Int_t optUseWeights)
740 // Calculate the point at minimum distance to prepared tracks
742 const Int_t knacc = (Int_t)lines->GetEntriesFast();
743 Double_t initPos[3]={0.,0.,0.};
745 Double_t (*vectP0)[3]=new Double_t [knacc][3];
746 Double_t (*vectP1)[3]=new Double_t [knacc][3];
749 Double_t dsum[3]={0,0,0};
751 for(Int_t i=0;i<3;i++){
752 for(Int_t j=0;j<3;j++){
758 for(Int_t i=0; i<knacc; i++){
759 AliStrLine* line1 = (AliStrLine*)lines->At(i);
760 Double_t p0[3],cd[3],sigmasq[3];
764 line1->GetSigma2P0(sigmasq);
765 line1->GetWMatrix(wmat);
768 for(Int_t ia=0;ia<3;ia++){
769 for(Int_t ib=0;ib<3;ib++){
770 wWi(ia,ib)=wmat[iel];
777 Double_t p1[3]={p0[0]+cd[0],p0[1]+cd[1],p0[2]+cd[2]};
787 if(optUseWeights==0)GetStrLinDerivMatrix(p0,p1,matr,dknow);
788 else GetStrLinDerivMatrix(p0,p1,sigmasq,matr,dknow);
791 for(Int_t iii=0;iii<3;iii++){
792 dsum[iii]+=dknow[iii];
793 for(Int_t lj=0;lj<3;lj++) sum[iii][lj]+=matr[iii][lj];
797 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
798 Double_t covmatrix[6];
799 covmatrix[0] = invsumWi(0,0);
800 covmatrix[1] = invsumWi(0,1);
801 covmatrix[2] = invsumWi(1,1);
802 covmatrix[3] = invsumWi(0,2);
803 covmatrix[4] = invsumWi(1,2);
804 covmatrix[5] = invsumWi(2,2);
807 Double_t det=GetDeterminant3X3(sum);
811 for(Int_t zz=0;zz<3;zz++){
812 for(Int_t ww=0;ww<3;ww++){
813 for(Int_t kk=0;kk<3;kk++) vett[ww][kk]=sum[ww][kk];
815 for(Int_t kk=0;kk<3;kk++) vett[kk][zz]=dsum[kk];
816 initPos[zz]=GetDeterminant3X3(vett)/det;
820 for(Int_t i=0; i<knacc; i++){
821 Double_t p0[3]={0,0,0},p1[3]={0,0,0};
822 for(Int_t ii=0;ii<3;ii++){
823 p0[ii]=vectP0[i][ii];
824 p1[ii]=vectP1[i][ii];
826 sigma+=GetStrLinMinDist(p0,p1,initPos);
829 sigma=TMath::Sqrt(sigma);
833 AliESDVertex theVert(initPos,covmatrix,99999.,knacc);
834 theVert.SetDispersion(sigma);
839 //---------------------------------------------------------------------------
840 Bool_t AliVertexerTracks::TrackToPoint(AliESDtrack *t,
841 TMatrixD &ri,TMatrixD &wWi,
842 Bool_t uUi3by3) const
845 // Extract from the AliESDtrack the global coordinates ri and covariance matrix
846 // wWi of the space point that it represents (to be used in VertexFitter())
850 Double_t rotAngle = t->GetAlpha();
851 if(rotAngle<0.) rotAngle += 2.*TMath::Pi();
852 Double_t cosRot = TMath::Cos(rotAngle);
853 Double_t sinRot = TMath::Sin(rotAngle);
855 ri(0,0) = t->GetX()*cosRot-t->GetY()*sinRot;
856 ri(1,0) = t->GetX()*sinRot+t->GetY()*cosRot;
862 // matrix to go from global (x,y,z) to local (y,z);
871 // covariance matrix of local (y,z) - inverted
873 t->GetExternalCovariance(cc);
880 //printf(" %f %f\n",uUi(0,0),uUi(0,1));
881 //printf(" %f %f\n",uUi(1,0),uUi(1,1));
883 if(uUi.Determinant() <= 0.) return kFALSE;
884 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
886 // weights matrix: wWi = qQiT * uUiInv * qQi
887 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
888 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
891 if(fVert.GetNContributors()<1) AliFatal("Vertex from finder is empty");
892 // matrix to go from global (x,y,z) to local (x,y,z);
904 // covariance of fVert along the track
905 Double_t p[3],pt,ptot;
907 pt = TMath::Sqrt(p[0]*p[0]+p[1]*p[1]);
908 ptot = TMath::Sqrt(pt*pt+p[2]*p[2]);
909 Double_t cp = p[0]/pt; //cos(phi)=px/pt
910 Double_t sp = p[1]/pt; //sin(phi)=py/pt
911 Double_t ct = p[2]/ptot; //cos(theta)=pz/ptot
912 Double_t st = TMath::Sqrt(1.-ct*ct); //sin(theta)
913 Double_t covfVert[6];
914 fVert.GetCovMatrix(covfVert);
915 Double_t covfVertalongt =
916 covfVert[0]*cp*cp*ct*ct
917 +covfVert[1]*2.*cp*sp*ct*ct
918 +covfVert[3]*2.*cp*ct*st
919 +covfVert[2]*sp*sp*ct*ct
920 +covfVert[4]*2.*sp*ct*st
923 t->GetExternalCovariance(cc);
924 // covariance matrix of local (x,y,z) - inverted
926 Double_t nSigma = 2.;
927 uUi(0,0) = covfVertalongt * nSigma * nSigma;
928 if(fDebug) printf("=====> sqrtUi00 cm %f\n",TMath::Sqrt(uUi(0,0)));
938 //printf(" %f %f\n",uUi(0,0),uUi(0,1));
939 //printf(" %f %f\n",uUi(1,0),uUi(1,1));
941 if(uUi.Determinant() <= 0.) return kFALSE;
942 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
944 // weights matrix: wWi = qQiT * uUiInv * qQi
945 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
946 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
953 //---------------------------------------------------------------------------
954 void AliVertexerTracks::TooFewTracks(const AliESD* esdEvent)
957 // When the number of tracks is < fMinTracks
960 // deal with vertices not found
961 Double_t pos[3],err[3];
963 pos[0] = fNominalPos[0];
964 err[0] = TMath::Sqrt(fNominalCov[0]);
965 pos[1] = fNominalPos[1];
966 err[1] = TMath::Sqrt(fNominalCov[2]);
967 pos[2] = esdEvent->GetVertex()->GetZv();
968 err[2] = esdEvent->GetVertex()->GetZRes();
969 if(err[0]>1. && esdEvent->GetVertex()->GetNContributors()<=0)
970 ncontr = -1; // (x,y,z) = (0,0,0)
971 if(err[0]>1. && esdEvent->GetVertex()->GetNContributors()>0)
972 ncontr = -2; // (x,y,z) = (0,0,z_fromSPD)
973 if(err[0]<1. && esdEvent->GetVertex()->GetNContributors()<=0)
974 ncontr = -3; // (x,y,z) = (x_mean,y_mean,0)
975 if(err[0]<1. && esdEvent->GetVertex()->GetNContributors()>0)
976 ncontr = -4; // (x,y,z) = (x_mean,y_mean,z_fromSPD)
978 fCurrentVertex = new AliESDVertex(pos,err);
979 fCurrentVertex->SetNContributors(ncontr);
982 esdEvent->GetVertex()->GetTruePos(tp);
983 fCurrentVertex->SetTruePos(tp);
985 fCurrentVertex->SetTitle("VertexerTracksWithConstraint");
987 fCurrentVertex->SetTitle("VertexerTracksNoConstraint");
992 //---------------------------------------------------------------------------
993 void AliVertexerTracks::VertexFinder(Int_t optUseWeights)
996 // Get estimate of vertex position in (x,y) from tracks DCA
1000 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
1001 Int_t nacc = (Int_t)fTrkArray.GetEntriesFast();
1002 Double_t aver[3]={0.,0.,0.};
1003 Double_t aversq[3]={0.,0.,0.};
1004 Double_t sigmasq[3]={0.,0.,0.};
1007 AliESDtrack *track1;
1008 AliESDtrack *track2;
1009 Double_t pos[3],dir[3];
1010 Double_t alpha,mindist;
1011 Double_t field=GetFieldkG();
1013 for(Int_t i=0; i<nacc; i++){
1014 track1 = (AliESDtrack*)fTrkArray.At(i);
1015 alpha=track1->GetAlpha();
1016 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1017 track1->GetXYZAt(mindist,field,pos);
1018 track1->GetPxPyPzAt(mindist,field,dir);
1019 AliStrLine *line1 = new AliStrLine(pos,dir);
1021 // AliStrLine *line1 = new AliStrLine();
1022 // track1->ApproximateHelixWithLine(mindist,field,line1);
1024 for(Int_t j=i+1; j<nacc; j++){
1025 track2 = (AliESDtrack*)fTrkArray.At(j);
1026 alpha=track2->GetAlpha();
1027 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1028 track2->GetXYZAt(mindist,field,pos);
1029 track2->GetPxPyPzAt(mindist,field,dir);
1030 AliStrLine *line2 = new AliStrLine(pos,dir);
1031 // AliStrLine *line2 = new AliStrLine();
1032 // track2->ApproximateHelixWithLine(mindist,field,line2);
1033 Double_t distCA=line2->GetDCA(line1);
1034 //printf("%d %d %f\n",i,j,distCA);
1035 if(fDCAcut<=0 || (fDCAcut>0&&distCA<fDCAcut)){
1036 Double_t pnt1[3],pnt2[3],crosspoint[3];
1038 if(optUseWeights<=0){
1039 Int_t retcode = line2->Cross(line1,crosspoint);
1042 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
1043 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1046 if(optUseWeights>0){
1047 Int_t retcode = line1->CrossPoints(line2,pnt1,pnt2);
1050 alpha=track1->GetAlpha();
1051 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
1052 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
1053 alpha=track2->GetAlpha();
1054 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
1055 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
1056 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
1057 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
1058 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
1059 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
1060 crosspoint[0]=wx1*pnt1[0] + wx2*pnt2[0];
1061 crosspoint[1]=wy1*pnt1[1] + wy2*pnt2[1];
1062 crosspoint[2]=wz1*pnt1[2] + wz2*pnt2[2];
1065 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
1066 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1075 for(Int_t jj=0;jj<3;jj++){
1076 initPos[jj] = aver[jj]/ncombi;
1077 //printf("%f\n",initPos[jj]);
1079 sigmasq[jj]=aversq[jj]-initPos[jj]*initPos[jj];
1082 sigma=TMath::Sqrt(TMath::Abs(sigma));
1085 Warning("VertexFinder","Finder did not succed");
1088 fVert.SetXYZ(initPos);
1089 fVert.SetDispersion(sigma);
1090 fVert.SetNContributors(ncombi);
1092 //---------------------------------------------------------------------------
1093 void AliVertexerTracks::VertexFitter(Bool_t useConstraint)
1096 // The optimal estimate of the vertex position is given by a "weighted
1097 // average of tracks positions".
1098 // Original method: V. Karimaki, CMS Note 97/0051
1100 Double_t initPos[3];
1102 fVert.GetXYZ(initPos);
1104 initPos[0]=fNominalPos[0];
1105 initPos[1]=fNominalPos[1];
1106 initPos[2]=fNominalPos[2];
1109 Int_t nTrks = (Int_t)fTrkArray.GetEntries();
1110 if(nTrks==1) useConstraint=kTRUE;
1112 printf("--- VertexFitter(): start\n");
1113 printf(" Number of tracks in array: %d\n",nTrks);
1114 printf(" Minimum # tracks required in fit: %d\n",fMinTracks);
1115 if(!fOnlyFitter) printf(" Vertex position after finder: %f,%f,%f\n",initPos[0],initPos[1],initPos[2]);
1116 if(useConstraint) printf(" This vertex will be used in fit: (%f+-%f,%f+-%f)\n",fNominalPos[0],TMath::Sqrt(fNominalCov[0]),fNominalPos[1],TMath::Sqrt(fNominalCov[2]));
1119 // special treatment for few-tracks fits (e.g. secondary vertices)
1120 Bool_t uUi3by3 = kFALSE; if(nTrks<5 && !useConstraint) uUi3by3 = kTRUE;
1125 rv(0,0) = initPos[0];
1126 rv(1,0) = initPos[1];
1128 Double_t xlStart,alpha;
1130 Double_t chi2,chi2i,chi2b;
1134 // initial vertex covariance matrix
1136 vVb(0,0) = fNominalCov[0];
1137 vVb(0,1) = fNominalCov[1];
1139 vVb(1,0) = fNominalCov[1];
1140 vVb(1,1) = fNominalCov[2];
1144 vVb(2,2) = fNominalCov[5];
1145 TMatrixD vVbInv(TMatrixD::kInverted,vVb);
1147 rb(0,0) = fNominalPos[0];
1148 rb(1,0) = fNominalPos[1];
1149 rb(2,0) = fNominalPos[2];
1150 TMatrixD vVbInvrb(vVbInv,TMatrixD::kMult,rb);
1154 // 1st - estimate of vtx using all tracks
1155 // 2nd - estimate of global chi2
1156 for(step=0; step<2; step++) {
1157 if(fDebug) printf(" step = %d\n",step);
1161 if(step==1) { initPos[0]=rv(0,0); initPos[0]=rv(1,0); }
1163 TMatrixD sumWiri(3,1);
1164 TMatrixD sumWi(3,3);
1165 for(i=0; i<3; i++) {
1167 for(j=0; j<3; j++) sumWi(j,i) = 0.;
1170 // mean vertex constraint
1173 sumWiri(i,0) += vVbInvrb(i,0);
1174 for(k=0;k<3;k++) sumWi(i,k) += vVbInv(i,k);
1177 TMatrixD deltar = rv; deltar -= rb;
1178 TMatrixD vVbInvdeltar(vVbInv,TMatrixD::kMult,deltar);
1179 chi2b = deltar(0,0)*vVbInvdeltar(0,0)+
1180 deltar(1,0)*vVbInvdeltar(1,0)+
1181 deltar(2,0)*vVbInvdeltar(2,0);
1186 for(k=0; k<nTrks; k++) {
1187 // get track from track array
1188 t = (AliESDtrack*)fTrkArray.At(k);
1189 alpha = t->GetAlpha();
1190 xlStart = initPos[0]*TMath::Cos(alpha)+initPos[1]*TMath::Sin(alpha);
1191 // to vtxSeed (from finder)
1192 t->AliExternalTrackParam::PropagateTo(xlStart,GetFieldkG());
1194 // vector of track global coordinates
1196 // covariance matrix of ri
1199 // get space point from track
1200 if(!TrackToPoint(t,ri,wWi,uUi3by3)) continue;
1201 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
1204 TMatrixD deltar = rv; deltar -= ri;
1205 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
1206 chi2i = deltar(0,0)*wWideltar(0,0)+
1207 deltar(1,0)*wWideltar(1,0)+
1208 deltar(2,0)*wWideltar(2,0);
1210 // add to total chi2
1217 } // end loop on tracks
1219 if(nUsedTrks < fMinTracks) {
1224 Double_t determinant = sumWi.Determinant();
1225 //cerr<<" determinant: "<<determinant<<endl;
1226 if(determinant < 100.) {
1227 printf("det(V) = 0\n");
1233 // inverted of weights matrix
1234 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
1236 // position of primary vertex
1237 rv.Mult(vV,sumWiri);
1239 } // end loop on the 2 steps
1242 if(fDebug) printf("TooFewTracks\n");
1243 fCurrentVertex = new AliESDVertex(0.,0.,-1);
1247 Double_t position[3];
1248 position[0] = rv(0,0);
1249 position[1] = rv(1,0);
1250 position[2] = rv(2,0);
1251 Double_t covmatrix[6];
1252 covmatrix[0] = vV(0,0);
1253 covmatrix[1] = vV(0,1);
1254 covmatrix[2] = vV(1,1);
1255 covmatrix[3] = vV(0,2);
1256 covmatrix[4] = vV(1,2);
1257 covmatrix[5] = vV(2,2);
1259 // for correct chi2/ndf, count constraint as additional "track"
1260 if(fConstraint) nUsedTrks++;
1261 // store data in the vertex object
1262 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nUsedTrks);
1265 printf(" Vertex after fit:\n");
1266 fCurrentVertex->PrintStatus();
1267 printf("--- VertexFitter(): finish\n");
1272 //----------------------------------------------------------------------------
1273 AliESDVertex* AliVertexerTracks::VertexForSelectedTracks(TTree *trkTree,Bool_t optUseFitter,Bool_t optPropagate)
1276 // Return vertex from tracks in trkTree
1281 // get tracks and propagate them to initial vertex position
1282 Int_t nTrksPrep = PrepareTracks(*trkTree,0);
1283 if(nTrksPrep < TMath::Max(2,fMinTracks) ) {
1284 if(fDebug) printf("TooFewTracks\n");
1285 fCurrentVertex = new AliESDVertex(0.,0.,-1);
1286 return fCurrentVertex;
1290 case 1: StrLinVertexFinderMinDist(1); break;
1291 case 2: StrLinVertexFinderMinDist(0); break;
1292 case 3: HelixVertexFinder(); break;
1293 case 4: VertexFinder(1); break;
1294 case 5: VertexFinder(0); break;
1295 default: printf("Wrong algorithm\n"); break;
1298 if(fDebug) printf(" Vertex finding completed\n");
1302 VertexFitter(fConstraint);
1303 if(fDebug) printf(" Vertex fit completed\n");
1305 Double_t position[3]={fVert.GetXv(),fVert.GetYv(),fVert.GetZv()};
1306 Double_t covmatrix[6];
1307 fVert.GetCovMatrix(covmatrix);
1308 Double_t chi2=99999.;
1309 Int_t nUsedTrks=fVert.GetNContributors();
1310 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nUsedTrks);
1312 fCurrentVertex->SetDispersion(fVert.GetDispersion());
1315 // set indices of used tracks and propagate track to found vertex
1316 UShort_t *indices = 0;
1317 AliESDtrack *eta = 0;
1318 if(fCurrentVertex->GetNContributors()>0) {
1319 indices = new UShort_t[fCurrentVertex->GetNContributors()];
1320 for(Int_t jj=0;jj<(Int_t)fTrkArray.GetEntriesFast();jj++) {
1321 eta = (AliESDtrack*)fTrkArray.At(jj);
1322 indices[jj] = (UShort_t)eta->GetID();
1323 if(optPropagate&&optUseFitter){
1324 if(TMath::Sqrt(fCurrentVertex->GetXv()*fCurrentVertex->GetXv()+fCurrentVertex->GetYv()*fCurrentVertex->GetYv())<3.) {
1325 eta->RelateToVertex(fCurrentVertex,GetFieldkG(),100.);
1326 if(fDebug) printf("Track %d propagated to found vertex\n",jj);
1328 AliWarning("Found vertex outside beam pipe!");
1332 fCurrentVertex->SetIndices(fCurrentVertex->GetNContributors(),indices);
1337 return fCurrentVertex;
1339 //----------------------------------------------------------------------------
1340 AliESDVertex* AliVertexerTracks::VertexForSelectedTracks(TObjArray *trkArray,Bool_t optUseFitter, Bool_t optPropagate)
1343 // Return vertex from array of tracks
1346 // get tracks and propagate them to initial vertex position
1347 Int_t nTrks = trkArray->GetEntriesFast();
1348 if(nTrks < TMath::Max(2,fMinTracks) ) {
1349 if(fDebug) printf("TooFewTracks\n");
1350 fCurrentVertex = new AliESDVertex(0.,0.,-1);
1351 return fCurrentVertex;
1353 TTree *trkTree = new TTree("TreeT","tracks");
1354 AliESDtrack *esdTrack = 0;
1355 trkTree->Branch("tracks","AliESDtrack",&esdTrack);
1356 for(Int_t i=0; i<nTrks; i++){
1357 esdTrack = (AliESDtrack*)trkArray->At(i);
1361 AliESDVertex *vtx = VertexForSelectedTracks(trkTree,optUseFitter,optPropagate);
1365 //--------------------------------------------------------------------------