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) const
844 // Extract from the AliESDtrack the global coordinates ri and covariance matrix
845 // wWi of the space point that it represents (to be used in VertexFitter())
849 Double_t rotAngle = t->GetAlpha();
850 if(rotAngle<0.) rotAngle += 2.*TMath::Pi();
851 Double_t cosRot = TMath::Cos(rotAngle);
852 Double_t sinRot = TMath::Sin(rotAngle);
854 ri(0,0) = t->GetX()*cosRot-t->GetY()*sinRot;
855 ri(1,0) = t->GetX()*sinRot+t->GetY()*cosRot;
858 // matrix to go from global (x,y,z) to local (y,z);
867 // covariance matrix of local (y,z) - inverted
870 t->GetExternalCovariance(cc);
876 if(uUi.Determinant() <= 0.) return kFALSE;
877 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
879 // weights matrix: wWi = qQiT * uUiInv * qQi
880 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
881 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
886 //---------------------------------------------------------------------------
887 void AliVertexerTracks::TooFewTracks(const AliESD* esdEvent)
890 // When the number of tracks is < fMinTracks
893 // deal with vertices not found
894 Double_t pos[3],err[3];
896 pos[0] = fNominalPos[0];
897 err[0] = TMath::Sqrt(fNominalCov[0]);
898 pos[1] = fNominalPos[1];
899 err[1] = TMath::Sqrt(fNominalCov[2]);
900 pos[2] = esdEvent->GetVertex()->GetZv();
901 err[2] = esdEvent->GetVertex()->GetZRes();
902 if(err[0]>1. && esdEvent->GetVertex()->GetNContributors()<=0)
903 ncontr = -1; // (x,y,z) = (0,0,0)
904 if(err[0]>1. && esdEvent->GetVertex()->GetNContributors()>0)
905 ncontr = -2; // (x,y,z) = (0,0,z_fromSPD)
906 if(err[0]<1. && esdEvent->GetVertex()->GetNContributors()<=0)
907 ncontr = -3; // (x,y,z) = (x_mean,y_mean,0)
908 if(err[0]<1. && esdEvent->GetVertex()->GetNContributors()>0)
909 ncontr = -4; // (x,y,z) = (x_mean,y_mean,z_fromSPD)
911 fCurrentVertex = new AliESDVertex(pos,err);
912 fCurrentVertex->SetNContributors(ncontr);
915 esdEvent->GetVertex()->GetTruePos(tp);
916 fCurrentVertex->SetTruePos(tp);
918 fCurrentVertex->SetTitle("VertexerTracksWithConstraint");
920 fCurrentVertex->SetTitle("VertexerTracksNoConstraint");
925 //---------------------------------------------------------------------------
926 void AliVertexerTracks::VertexFinder(Int_t optUseWeights)
929 // Get estimate of vertex position in (x,y) from tracks DCA
933 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
934 Int_t nacc = (Int_t)fTrkArray.GetEntriesFast();
935 Double_t aver[3]={0.,0.,0.};
936 Double_t aversq[3]={0.,0.,0.};
937 Double_t sigmasq[3]={0.,0.,0.};
942 Double_t pos[3],dir[3];
943 Double_t alpha,mindist;
944 Double_t field=GetFieldkG();
946 for(Int_t i=0; i<nacc; i++){
947 track1 = (AliESDtrack*)fTrkArray.At(i);
948 alpha=track1->GetAlpha();
949 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
950 track1->GetXYZAt(mindist,field,pos);
951 track1->GetPxPyPzAt(mindist,field,dir);
952 AliStrLine *line1 = new AliStrLine(pos,dir);
954 // AliStrLine *line1 = new AliStrLine();
955 // track1->ApproximateHelixWithLine(mindist,field,line1);
957 for(Int_t j=i+1; j<nacc; j++){
958 track2 = (AliESDtrack*)fTrkArray.At(j);
959 alpha=track2->GetAlpha();
960 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
961 track2->GetXYZAt(mindist,field,pos);
962 track2->GetPxPyPzAt(mindist,field,dir);
963 AliStrLine *line2 = new AliStrLine(pos,dir);
964 // AliStrLine *line2 = new AliStrLine();
965 // track2->ApproximateHelixWithLine(mindist,field,line2);
966 Double_t distCA=line2->GetDCA(line1);
967 //printf("%d %d %f\n",i,j,distCA);
968 if(fDCAcut<=0 || (fDCAcut>0&&distCA<fDCAcut)){
969 Double_t pnt1[3],pnt2[3],crosspoint[3];
971 if(optUseWeights<=0){
972 Int_t retcode = line2->Cross(line1,crosspoint);
975 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
976 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
980 Int_t retcode = line1->CrossPoints(line2,pnt1,pnt2);
983 alpha=track1->GetAlpha();
984 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
985 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
986 alpha=track2->GetAlpha();
987 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
988 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
989 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
990 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
991 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
992 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
993 crosspoint[0]=wx1*pnt1[0] + wx2*pnt2[0];
994 crosspoint[1]=wy1*pnt1[1] + wy2*pnt2[1];
995 crosspoint[2]=wz1*pnt1[2] + wz2*pnt2[2];
998 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
999 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1008 for(Int_t jj=0;jj<3;jj++){
1009 initPos[jj] = aver[jj]/ncombi;
1010 //printf("%f\n",initPos[jj]);
1012 sigmasq[jj]=aversq[jj]-initPos[jj]*initPos[jj];
1015 sigma=TMath::Sqrt(TMath::Abs(sigma));
1018 Warning("VertexFinder","Finder did not succed");
1021 fVert.SetXYZ(initPos);
1022 fVert.SetDispersion(sigma);
1023 fVert.SetNContributors(ncombi);
1025 //---------------------------------------------------------------------------
1026 void AliVertexerTracks::VertexFitter(Bool_t useConstraint)
1029 // The optimal estimate of the vertex position is given by a "weighted
1030 // average of tracks positions"
1031 // Original method: V. Karimaki, CMS Note 97/0051
1033 Double_t initPos[3];
1034 fVert.GetXYZ(initPos);
1035 Int_t arrEntries = (Int_t)fTrkArray.GetEntries();
1036 if(arrEntries==1) useConstraint=kTRUE;
1038 printf(" VertexFitter(): start\n");
1039 printf(" Number of tracks in array: %d\n",(Int_t)fTrkArray.GetEntriesFast());
1040 printf(" Minimum # tracks required in fit: %d\n",fMinTracks);
1041 printf("Vertex position after finder: %f,%f,%f\n",initPos[0],initPos[1],initPos[2]);
1042 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]));
1048 rv(0,0) = initPos[0];
1049 rv(1,0) = initPos[1];
1051 Double_t xlStart,alpha;
1053 Double_t chi2,chi2i,chi2b;
1057 // initial vertex covariance matrix
1059 vVb(0,0) = fNominalCov[0];
1060 vVb(0,1) = fNominalCov[1];
1062 vVb(1,0) = fNominalCov[1];
1063 vVb(1,1) = fNominalCov[2];
1067 vVb(2,2) = fNominalCov[5];
1068 TMatrixD vVbInv(TMatrixD::kInverted,vVb);
1070 rb(0,0) = fNominalPos[0];
1071 rb(1,0) = fNominalPos[1];
1072 rb(2,0) = fNominalPos[2];
1073 TMatrixD vVbInvrb(vVbInv,TMatrixD::kMult,rb);
1077 // 1st - estimate of vtx using all tracks
1078 // 2nd - estimate of global chi2
1079 for(step=0; step<2; step++) {
1080 if(fDebug) printf(" step = %d\n",step);
1084 TMatrixD sumWiri(3,1);
1085 TMatrixD sumWi(3,3);
1086 for(i=0; i<3; i++) {
1088 for(j=0; j<3; j++) sumWi(j,i) = 0.;
1091 // mean vertex constraint
1094 sumWiri(i,0) += vVbInvrb(i,0);
1095 for(k=0;k<3;k++) sumWi(i,k) += vVbInv(i,k);
1098 TMatrixD deltar = rv; deltar -= rb;
1099 TMatrixD vVbInvdeltar(vVbInv,TMatrixD::kMult,deltar);
1100 chi2b = deltar(0,0)*vVbInvdeltar(0,0)+
1101 deltar(1,0)*vVbInvdeltar(1,0)+
1102 deltar(2,0)*vVbInvdeltar(2,0);
1108 for(k=0; k<arrEntries; k++) {
1109 // get track from track array
1110 t = (AliESDtrack*)fTrkArray.At(k);
1111 alpha = t->GetAlpha();
1112 xlStart = initPos[0]*TMath::Cos(alpha)+initPos[1]*TMath::Sin(alpha);
1113 // to vtxSeed (from finder)
1114 t->AliExternalTrackParam::PropagateTo(xlStart,GetFieldkG());
1117 // vector of track global coordinates
1119 // covariance matrix of ri
1122 // get space point from track
1123 if(!TrackToPoint(t,ri,wWi)) continue;
1124 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
1127 TMatrixD deltar = rv; deltar -= ri;
1128 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
1129 chi2i = deltar(0,0)*wWideltar(0,0)+
1130 deltar(1,0)*wWideltar(1,0)+
1131 deltar(2,0)*wWideltar(2,0);
1133 // add to total chi2
1140 } // end loop on tracks
1142 if(nUsedTrks < fMinTracks) {
1147 Double_t determinant = sumWi.Determinant();
1148 //cerr<<" determinant: "<<determinant<<endl;
1149 if(determinant < 100.) {
1150 printf("det(V) = 0\n");
1155 // inverted of weights matrix
1156 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
1159 // position of primary vertex
1160 rv.Mult(vV,sumWiri);
1162 } // end loop on the 2 steps
1167 if(fDebug) printf("TooFewTracks\n");
1168 fCurrentVertex = new AliESDVertex(0.,0.,-1);
1172 Double_t position[3];
1173 position[0] = rv(0,0);
1174 position[1] = rv(1,0);
1175 position[2] = rv(2,0);
1176 Double_t covmatrix[6];
1177 covmatrix[0] = vV(0,0);
1178 covmatrix[1] = vV(0,1);
1179 covmatrix[2] = vV(1,1);
1180 covmatrix[3] = vV(0,2);
1181 covmatrix[4] = vV(1,2);
1182 covmatrix[5] = vV(2,2);
1184 // for correct chi2/ndf, count constraint as additional "track"
1185 if(fConstraint) nUsedTrks++;
1186 // store data in the vertex object
1187 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nUsedTrks);
1190 printf(" VertexFitter(): finish\n");
1191 printf(" rv = ( %f , %f , %f )\n\n",rv(0,0),rv(1,0),rv(2,0));
1192 fCurrentVertex->PrintStatus();
1197 //----------------------------------------------------------------------------
1198 AliESDVertex* AliVertexerTracks::VertexForSelectedTracks(TTree *trkTree,Bool_t optUseFitter,Bool_t optPropagate)
1201 // Return vertex from tracks in trkTree
1206 // get tracks and propagate them to initial vertex position
1207 Int_t nTrksPrep = PrepareTracks(*trkTree,0);
1208 if(nTrksPrep < TMath::Max(2,fMinTracks) ) {
1209 if(fDebug) printf("TooFewTracks\n");
1210 fCurrentVertex = new AliESDVertex(0.,0.,-1);
1211 return fCurrentVertex;
1215 case 1: StrLinVertexFinderMinDist(1); break;
1216 case 2: StrLinVertexFinderMinDist(0); break;
1217 case 3: HelixVertexFinder(); break;
1218 case 4: VertexFinder(1); break;
1219 case 5: VertexFinder(0); break;
1220 default: printf("Wrong algorithm\n"); break;
1223 if(fDebug) printf(" Vertex finding completed\n");
1227 VertexFitter(fConstraint);
1228 if(fDebug) printf(" Vertex fit completed\n");
1230 Double_t position[3]={fVert.GetXv(),fVert.GetYv(),fVert.GetZv()};
1231 Double_t covmatrix[6];
1232 fVert.GetCovMatrix(covmatrix);
1233 Double_t chi2=99999.;
1234 Int_t nUsedTrks=fVert.GetNContributors();
1235 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nUsedTrks);
1237 fCurrentVertex->SetDispersion(fVert.GetDispersion());
1240 // set indices of used tracks and propagate track to found vertex
1241 UShort_t *indices = 0;
1242 AliESDtrack *eta = 0;
1243 if(fCurrentVertex->GetNContributors()>0) {
1244 indices = new UShort_t[fCurrentVertex->GetNContributors()];
1245 for(Int_t jj=0;jj<(Int_t)fTrkArray.GetEntriesFast();jj++) {
1246 eta = (AliESDtrack*)fTrkArray.At(jj);
1247 indices[jj] = (UShort_t)eta->GetID();
1248 if(optPropagate&&optUseFitter){
1249 if(TMath::Sqrt(fCurrentVertex->GetXv()*fCurrentVertex->GetXv()+fCurrentVertex->GetYv()*fCurrentVertex->GetYv())<3.) {
1250 eta->RelateToVertex(fCurrentVertex,GetFieldkG(),100.);
1251 if(fDebug) printf("Track %d propagated to found vertex\n",jj);
1253 AliWarning("Found vertex outside beam pipe!");
1257 fCurrentVertex->SetIndices(fCurrentVertex->GetNContributors(),indices);
1262 return fCurrentVertex;
1264 //----------------------------------------------------------------------------
1265 AliESDVertex* AliVertexerTracks::VertexForSelectedTracks(TObjArray *trkArray,Bool_t optUseFitter, Bool_t optPropagate)
1268 // Return vertex from array of tracks
1271 // get tracks and propagate them to initial vertex position
1272 Int_t nTrks = trkArray->GetEntriesFast();
1273 if(nTrks < TMath::Max(2,fMinTracks) ) {
1274 if(fDebug) printf("TooFewTracks\n");
1275 fCurrentVertex = new AliESDVertex(0.,0.,-1);
1276 return fCurrentVertex;
1278 TTree *trkTree = new TTree("TreeT","tracks");
1279 AliESDtrack *esdTrack = 0;
1280 trkTree->Branch("tracks","AliESDtrack",&esdTrack);
1281 for(Int_t i=0; i<nTrks; i++){
1282 esdTrack = (AliESDtrack*)trkArray->At(i);
1286 AliESDVertex *vtx = VertexForSelectedTracks(trkTree,optUseFitter,optPropagate);
1290 //--------------------------------------------------------------------------