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 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 --------
30 #include <TDirectory.h>
34 //---- AliRoot headers -----
36 #include "AliStrLine.h"
37 #include "AliExternalTrackParam.h"
38 #include "AliVEvent.h"
39 #include "AliVTrack.h"
40 #include "AliESDEvent.h"
41 #include "AliESDtrack.h"
42 #include "AliVertexerTracks.h"
44 ClassImp(AliVertexerTracks)
47 //----------------------------------------------------------------------------
48 AliVertexerTracks::AliVertexerTracks():
75 // Default constructor
80 //----------------------------------------------------------------------------
81 AliVertexerTracks::AliVertexerTracks(Double_t fieldkG):
108 // Standard constructor
113 //-----------------------------------------------------------------------------
114 AliVertexerTracks::~AliVertexerTracks()
116 // Default Destructor
117 // The objects pointed by the following pointer are not owned
118 // by this class and are not deleted
120 if(fTrksToSkip) { delete [] fTrksToSkip; fTrksToSkip=NULL; }
121 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
123 //----------------------------------------------------------------------------
124 AliESDVertex* AliVertexerTracks::FindPrimaryVertex(const AliVEvent *vEvent)
127 // Primary vertex for current ESD or AOD event
129 // 1st with 5*fNSigma*sigma cut w.r.t. to initial vertex
130 // + cut on sqrt(d0d0+z0z0) if fConstraint=kFALSE
131 // 2nd with fNSigma*sigma cut w.r.t. to vertex found in 1st iteration)
135 TString evtype = vEvent->IsA()->GetName();
136 Bool_t inputAOD = ((evtype=="AliAODEvent") ? kTRUE : kFALSE);
138 if(inputAOD && fMode==1) {
139 printf("Error : AliVertexerTracks: no TPC-only vertex from AOD\n");
141 return fCurrentVertex;
144 // accept 1-track case only if constraint is available
145 if(!fConstraint && fMinTracks==1) fMinTracks=2;
147 // read tracks from AlivEvent
148 Int_t nTrks = (Int_t)vEvent->GetNumberOfTracks();
149 if(nTrks<fMinTracks) {
151 return fCurrentVertex;
155 TDirectory * olddir = gDirectory;
157 if(nTrks>500) f = new TFile("VertexerTracks.root","recreate");
158 TObjArray trkArrayOrig(nTrks);
159 UShort_t *idOrig = new UShort_t[nTrks];
162 AliExternalTrackParam *t=0;
164 for(Int_t i=0; i<nTrks; i++) {
165 AliVTrack *track = (AliVTrack*)vEvent->GetTrack(i);
167 if(fITSrefit && !(track->GetStatus()&AliESDtrack::kITSrefit)) continue;
169 // check number of clusters in ITS
171 for(Int_t l=0;l<6;l++) if(TESTBIT(track->GetITSClusterMap(),l)) ncls0++;
172 if(fMode==0 && ncls0 < fMinClusters) continue;
175 Double_t x,p[5],cov[15];
176 AliESDtrack* esdt = (AliESDtrack*)track;
177 if(esdt->GetNcls(fMode) < fMinClusters) continue;
178 esdt->GetExternalParameters(x,p);
179 esdt->GetExternalCovariance(cov);
180 t = new AliExternalTrackParam(x,esdt->GetAlpha(),p,cov);
182 t = new AliExternalTrackParam(track);
184 trkArrayOrig.AddLast(t);
185 idOrig[nTrksOrig]=(UShort_t)track->GetID();
187 } // end loop on tracks
189 // call method that will reconstruct the vertex
190 FindPrimaryVertex(&trkArrayOrig,idOrig);
192 trkArrayOrig.Delete();
193 delete [] idOrig; idOrig=NULL;
196 f->Close(); delete f; f = NULL;
197 gSystem->Unlink("VertexerTracks.root");
201 return fCurrentVertex;
203 //----------------------------------------------------------------------------
204 AliESDVertex* AliVertexerTracks::FindPrimaryVertex(TObjArray *trkArrayOrig,
208 // Primary vertex using the AliExternalTrackParam's in the TObjArray.
209 // idOrig must contain the track IDs from AliESDtrack::GetID()
211 // 1st with 5*fNSigma*sigma cut w.r.t. to initial vertex
212 // + cut on sqrt(d0d0+z0z0) if fConstraint=kFALSE
213 // 2nd with fNSigma*sigma cut w.r.t. to vertex found in 1st iteration)
217 // accept 1-track case only if constraint is available
218 if(!fConstraint && fMinTracks==1) fMinTracks=2;
220 // read tracks from array
221 Int_t nTrksOrig = (Int_t)trkArrayOrig->GetEntriesFast();
222 AliDebug(1,Form("Initial number of tracks: %d",nTrksOrig));
223 if(nTrksOrig<fMinTracks) {
224 AliDebug(1,"TooFewTracks");
226 return fCurrentVertex;
229 // If fConstraint=kFALSE
230 // run VertexFinder(1) to get rough estimate of initVertex (x,y)
232 // fill fTrkArraySel, for VertexFinder()
233 fIdSel = new UShort_t[nTrksOrig];
234 PrepareTracks(*trkArrayOrig,idOrig,0);
235 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
236 Double_t cutsave = fDCAcut;
237 fDCAcut = fDCAcutIter0;
238 VertexFinder(1); // using weights, cutting dca < fDCAcutIter0
240 if(fVert.GetNContributors()>0) {
241 fVert.GetXYZ(fNominalPos);
242 fNominalPos[0] = fVert.GetXv();
243 fNominalPos[1] = fVert.GetYv();
244 fNominalPos[2] = fVert.GetZv();
245 AliDebug(1,Form("No mean vertex: VertexFinder gives (%f, %f, %f)",fNominalPos[0],fNominalPos[1],fNominalPos[2]));
250 AliDebug(1,"No mean vertex and VertexFinder failed");
257 // propagate tracks to fNominalPos vertex
259 // if(constraint) reject for |d0|>5*fNSigma*sigma w.r.t. fNominal... vertex
260 // else reject for |d0|\oplus|z0| > 5 mm w.r.t. fNominal... vertex
262 // propagate tracks to best between initVertex and fCurrentVertex
263 // preselect tracks (reject for |d0|>fNSigma*sigma w.r.t. best
264 // between initVertex and fCurrentVertex)
265 for(Int_t iter=1; iter<=2; iter++) {
266 if(fOnlyFitter && iter==1) continue;
267 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
268 fIdSel = new UShort_t[nTrksOrig];
269 Int_t nTrksSel = PrepareTracks(*trkArrayOrig,idOrig,iter);
270 AliDebug(1,Form("N tracks selected in iteration %d: %d",iter,nTrksSel));
271 if(nTrksSel < fMinTracks) {
273 return fCurrentVertex;
279 AliDebug(1,"Just one track");
280 OneTrackVertFinder();
283 case 1: StrLinVertexFinderMinDist(1); break;
284 case 2: StrLinVertexFinderMinDist(0); break;
285 case 3: HelixVertexFinder(); break;
286 case 4: VertexFinder(1); break;
287 case 5: VertexFinder(0); break;
288 default: printf("Wrong algorithm"); break;
291 AliDebug(1," Vertex finding completed");
296 } // end loop on the two iterations
299 // set indices of used tracks
300 UShort_t *indices = 0;
301 if(fCurrentVertex->GetNContributors()>0) {
302 Int_t nIndices = (Int_t)fTrkArraySel.GetEntriesFast();
303 indices = new UShort_t[nIndices];
304 for(Int_t jj=0; jj<nIndices; jj++)
305 indices[jj] = fIdSel[jj];
306 fCurrentVertex->SetIndices(nIndices,indices);
308 delete [] indices; indices=NULL;
312 TString title="VertexerTracksNoConstraint";
314 title="VertexerTracksWithConstraint";
315 if(fOnlyFitter) title.Append("OnlyFitter");
317 fCurrentVertex->SetTitle(title.Data());
320 AliDebug(1,Form("xyz: %f %f %f; nc %d",fCurrentVertex->GetXv(),fCurrentVertex->GetYv(),fCurrentVertex->GetZv(),fCurrentVertex->GetNContributors()));
323 delete [] fIdSel; fIdSel=NULL;
324 fTrkArraySel.Delete();
325 if(fTrksToSkip) { delete [] fTrksToSkip; fTrksToSkip=NULL; }
328 return fCurrentVertex;
330 //------------------------------------------------------------------------
331 Double_t AliVertexerTracks::GetDeterminant3X3(Double_t matr[][3])
334 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];
337 //-------------------------------------------------------------------------
338 void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t (*m)[3],Double_t *d)
341 Double_t x12=p0[0]-p1[0];
342 Double_t y12=p0[1]-p1[1];
343 Double_t z12=p0[2]-p1[2];
344 Double_t kk=x12*x12+y12*y12+z12*z12;
345 m[0][0]=2-2/kk*x12*x12;
346 m[0][1]=-2/kk*x12*y12;
347 m[0][2]=-2/kk*x12*z12;
348 m[1][0]=-2/kk*x12*y12;
349 m[1][1]=2-2/kk*y12*y12;
350 m[1][2]=-2/kk*y12*z12;
351 m[2][0]=-2/kk*x12*z12;
353 m[2][2]=2-2/kk*z12*z12;
354 d[0]=2*p0[0]-2/kk*p0[0]*x12*x12-2/kk*p0[2]*x12*z12-2/kk*p0[1]*x12*y12;
355 d[1]=2*p0[1]-2/kk*p0[1]*y12*y12-2/kk*p0[0]*x12*y12-2/kk*p0[2]*z12*y12;
356 d[2]=2*p0[2]-2/kk*p0[2]*z12*z12-2/kk*p0[0]*x12*z12-2/kk*p0[1]*z12*y12;
359 //--------------------------------------------------------------------------
360 void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t *sigmasq,Double_t (*m)[3],Double_t *d)
363 Double_t x12=p1[0]-p0[0];
364 Double_t y12=p1[1]-p0[1];
365 Double_t z12=p1[2]-p0[2];
367 Double_t den= x12*x12*sigmasq[1]*sigmasq[2]+y12*y12*sigmasq[0]*sigmasq[2]+z12*z12*sigmasq[0]*sigmasq[1];
369 Double_t kk= 2*(x12*x12/sigmasq[0]+y12*y12/sigmasq[1]+z12*z12/sigmasq[2]);
372 cc[0]=-x12/sigmasq[0];
373 cc[1]=-y12/sigmasq[1];
374 cc[2]=-z12/sigmasq[2];
376 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;
378 Double_t ss= -p0[0]*cc[0]-p0[1]*cc[1]-p0[2]*cc[2];
381 aa[0]=x12*sigmasq[1]*sigmasq[2]/den;
382 aa[1]=y12*sigmasq[0]*sigmasq[2]/den;
383 aa[2]=z12*sigmasq[0]*sigmasq[1]/den;
385 m[0][0]=aa[0]*(aa[0]*kk+2*cc[0])+2*cc[0]*aa[0]+2/sigmasq[0];
386 m[0][1]=aa[1]*(aa[0]*kk+2*cc[0])+2*cc[1]*aa[0];
387 m[0][2]=aa[2]*(aa[0]*kk+2*cc[0])+2*cc[2]*aa[0];
389 m[1][0]=aa[0]*(aa[1]*kk+2*cc[1])+2*cc[0]*aa[1];
390 m[1][1]=aa[1]*(aa[1]*kk+2*cc[1])+2*cc[1]*aa[1]+2/sigmasq[1];
391 m[1][2]=aa[2]*(aa[1]*kk+2*cc[1])+2*cc[2]*aa[1];
393 m[2][0]=aa[0]*(aa[2]*kk+2*cc[2])+2*cc[0]*aa[2];
394 m[2][1]=aa[1]*(aa[2]*kk+2*cc[2])+2*cc[1]*aa[2];
395 m[2][2]=aa[2]*(aa[2]*kk+2*cc[2])+2*cc[2]*aa[2]+2/sigmasq[2];
397 d[0]=-ww*(aa[0]*kk+2*cc[0])-2*ss*aa[0]+2*p0[0]/sigmasq[0];
398 d[1]=-ww*(aa[1]*kk+2*cc[1])-2*ss*aa[1]+2*p0[1]/sigmasq[1];
399 d[2]=-ww*(aa[2]*kk+2*cc[2])-2*ss*aa[2]+2*p0[2]/sigmasq[2];
402 //--------------------------------------------------------------------------
403 Double_t AliVertexerTracks::GetStrLinMinDist(Double_t *p0,Double_t *p1,Double_t *x0)
406 Double_t x12=p0[0]-p1[0];
407 Double_t y12=p0[1]-p1[1];
408 Double_t z12=p0[2]-p1[2];
409 Double_t x10=p0[0]-x0[0];
410 Double_t y10=p0[1]-x0[1];
411 Double_t z10=p0[2]-x0[2];
412 // 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);
413 return ((y10*z12-z10*y12)*(y10*z12-z10*y12)+
414 (z10*x12-x10*z12)*(z10*x12-x10*z12)+
415 (x10*y12-y10*x12)*(x10*y12-y10*x12))
416 /(x12*x12+y12*y12+z12*z12);
418 //---------------------------------------------------------------------------
419 void AliVertexerTracks::OneTrackVertFinder()
421 // find vertex for events with 1 track, using DCA to nominal beam axis
422 AliDebug(1,Form("Number of prepared tracks =%d - Call OneTrackVertFinder",fTrkArraySel.GetEntries()));
423 AliExternalTrackParam *track1;
424 track1 = (AliExternalTrackParam*)fTrkArraySel.At(0);
425 Double_t alpha=track1->GetAlpha();
426 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
427 Double_t pos[3],dir[3];
428 track1->GetXYZAt(mindist,GetFieldkG(),pos);
429 track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
430 AliStrLine *line1 = new AliStrLine(pos,dir);
431 Double_t p1[3]={fNominalPos[0],fNominalPos[1],0.};
432 Double_t p2[3]={fNominalPos[0],fNominalPos[1],10.};
433 AliStrLine *zeta=new AliStrLine(p1,p2,kTRUE);
434 Double_t crosspoint[3]={0.,0.,0.};
437 Int_t retcode = zeta->Cross(line1,crosspoint);
439 sigma=line1->GetDistFromPoint(crosspoint);
444 fVert.SetXYZ(crosspoint);
445 fVert.SetDispersion(sigma);
446 fVert.SetNContributors(nContrib);
448 //---------------------------------------------------------------------------
449 void AliVertexerTracks::HelixVertexFinder()
451 // Get estimate of vertex position in (x,y) from tracks DCA
456 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
458 Int_t nacc = (Int_t)fTrkArraySel.GetEntriesFast();
460 Double_t aver[3]={0.,0.,0.};
461 Double_t averquad[3]={0.,0.,0.};
462 Double_t sigmaquad[3]={0.,0.,0.};
465 AliExternalTrackParam *track1;
466 AliExternalTrackParam *track2;
469 Double_t alpha, cs, sn;
470 Double_t crosspoint[3];
471 for(Int_t i=0; i<nacc; i++){
472 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
475 for(Int_t j=i+1; j<nacc; j++){
476 track2 = (AliExternalTrackParam*)fTrkArraySel.At(j);
478 distCA=track2->PropagateToDCA(track1,GetFieldkG());
479 if(fDCAcut<=0 ||(fDCAcut>0&&distCA<fDCAcut)){
481 alpha=track1->GetAlpha();
482 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
483 Double_t x1=x*cs - track1->GetY()*sn;
484 Double_t y1=x*sn + track1->GetY()*cs;
485 Double_t z1=track1->GetZ();
487 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
489 alpha=track2->GetAlpha();
490 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
491 Double_t x2=x*cs - track2->GetY()*sn;
492 Double_t y2=x*sn + track2->GetY()*cs;
493 Double_t z2=track2->GetZ();
494 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
495 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
496 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
497 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
498 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
499 crosspoint[0]=wx1*x1 + wx2*x2;
500 crosspoint[1]=wy1*y1 + wy2*y2;
501 crosspoint[2]=wz1*z1 + wz2*z2;
504 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
505 for(Int_t jj=0;jj<3;jj++)averquad[jj]+=(crosspoint[jj]*crosspoint[jj]);
511 for(Int_t jj=0;jj<3;jj++){
512 initPos[jj] = aver[jj]/ncombi;
513 averquad[jj]/=ncombi;
514 sigmaquad[jj]=averquad[jj]-initPos[jj]*initPos[jj];
515 sigma+=sigmaquad[jj];
517 sigma=TMath::Sqrt(TMath::Abs(sigma));
520 Warning("HelixVertexFinder","Finder did not succed");
523 fVert.SetXYZ(initPos);
524 fVert.SetDispersion(sigma);
525 fVert.SetNContributors(ncombi);
527 //----------------------------------------------------------------------------
528 Int_t AliVertexerTracks::PrepareTracks(TObjArray &trkArrayOrig,
533 // Propagate tracks to initial vertex position and store them in a TObjArray
535 AliDebug(1," PrepareTracks()");
537 Int_t nTrksOrig = (Int_t)trkArrayOrig.GetEntriesFast();
540 Double_t sigmaCurr[3];
541 Double_t normdistx,normdisty;
542 Double_t d0z0[2],covd0z0[3];
545 AliESDVertex *initVertex = new AliESDVertex(fNominalPos,fNominalCov,1,1);
547 if(!fTrkArraySel.IsEmpty()) fTrkArraySel.Delete();
549 AliExternalTrackParam *track=0;
552 for(Int_t i=0; i<nTrksOrig; i++) {
553 track = new AliExternalTrackParam(*(AliExternalTrackParam*)trkArrayOrig.At(i));
555 if(TMath::Abs(track->GetTgl())>fMaxTgl) {
556 AliDebug(1,Form(" rejecting track with tgl = %f",track->GetTgl()));
557 delete track; continue;
560 Bool_t propagateOK = kFALSE;
561 // propagate track to vertex
562 if(optImpParCut<2 || fOnlyFitter) { // optImpParCut==1 or 0
563 propagateOK = track->PropagateToDCA(initVertex,GetFieldkG(),100.,d0z0,covd0z0);
564 } else { // optImpParCut==2
565 fCurrentVertex->GetSigmaXYZ(sigmaCurr);
566 normdistx = TMath::Abs(fCurrentVertex->GetXv()-fNominalPos[0])/TMath::Sqrt(sigmaCurr[0]*sigmaCurr[0]+fNominalCov[0]);
567 normdisty = TMath::Abs(fCurrentVertex->GetYv()-fNominalPos[1])/TMath::Sqrt(sigmaCurr[1]*sigmaCurr[1]+fNominalCov[2]);
568 if(normdistx < 3. && normdisty < 3. &&
569 (sigmaCurr[0]+sigmaCurr[1])<(TMath::Sqrt(fNominalCov[0])+TMath::Sqrt(fNominalCov[2]))) {
570 propagateOK = track->PropagateToDCA(fCurrentVertex,GetFieldkG(),100.,d0z0,covd0z0);
572 propagateOK = track->PropagateToDCA(initVertex,GetFieldkG(),100.,d0z0,covd0z0);
577 AliDebug(1," rejected");
578 delete track; continue;
581 sigmad0 = TMath::Sqrt(covd0z0[0]);
582 maxd0rphi = fNSigma*sigmad0;
583 if(optImpParCut==1) maxd0rphi *= 5.;
584 maxd0rphi = TMath::Min(maxd0rphi,fFiducialR);
585 //sigmad0z0 = TMath::Sqrt(covd0z0[0]+covd0z0[2]); // for future improvement
586 //maxd0z0 = 10.*fNSigma*sigmad0z0;
588 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));
591 //---- track selection based on impact parameters ----//
593 // always reject tracks outside fiducial volume
594 if(TMath::Abs(d0z0[0])>fFiducialR || TMath::Abs(d0z0[1])>fFiducialZ) {
595 AliDebug(1," rejected");
596 delete track; continue;
599 // during iterations 1 and 2 , reject tracks with d0rphi > maxd0rphi
600 if(optImpParCut>0 && TMath::Abs(d0z0[0])>maxd0rphi) {
601 AliDebug(1," rejected");
602 delete track; continue;
605 // if fConstraint=kFALSE, during iterations 1 and 2 ||
606 // if fConstraint=kTRUE, during iteration 2,
607 // select tracks with d0oplusz0 < fMaxd0z0
608 if((!fConstraint && optImpParCut>0 && fVert.GetNContributors()>0) ||
609 ( fConstraint && optImpParCut==2)) {
611 TMath::Sqrt(d0z0[0]*d0z0[0]+d0z0[1]*d0z0[1])>fMaxd0z0) {
612 AliDebug(1," rejected");
613 delete track; continue;
617 // track passed all selections
618 fTrkArraySel.AddLast(track);
619 fIdSel[nTrksSel] = idOrig[i];
621 } // end loop on tracks
627 //----------------------------------------------------------------------------
628 Bool_t AliVertexerTracks::PropagateTrackTo(AliExternalTrackParam *track,
630 //----------------------------------------------------------------
631 // COPIED from AliTracker
633 // Propagates the track to the plane X=xk (cm).
635 // Origin: Marian Ivanov, Marian.Ivanov@cern.ch
636 //----------------------------------------------------------------
638 const Double_t kEpsilon = 0.00001;
639 Double_t xpos = track->GetX();
640 Double_t dir = (xpos<xToGo) ? 1. : -1.;
641 Double_t maxStep = 5;
642 Double_t maxSnp = 0.8;
644 while ( (xToGo-xpos)*dir > kEpsilon){
645 Double_t step = dir*TMath::Min(TMath::Abs(xToGo-xpos), maxStep);
646 Double_t x = xpos+step;
647 Double_t xyz0[3],xyz1[3];
648 track->GetXYZ(xyz0); //starting global position
650 if(!track->GetXYZAt(x,GetFieldkG(),xyz1)) return kFALSE; // no prolongation
651 xyz1[2]+=kEpsilon; // waiting for bug correction in geo
653 if(TMath::Abs(track->GetSnpAt(x,GetFieldkG())) >= maxSnp) return kFALSE;
654 if(!track->PropagateTo(x,GetFieldkG())) return kFALSE;
656 if(TMath::Abs(track->GetSnp()) >= maxSnp) return kFALSE;
657 track->GetXYZ(xyz0); // global position
658 Double_t alphan = TMath::ATan2(xyz0[1], xyz0[0]);
660 Double_t ca=TMath::Cos(alphan-track->GetAlpha()),
661 sa=TMath::Sin(alphan-track->GetAlpha());
662 Double_t sf=track->GetSnp(), cf=TMath::Sqrt(1.- sf*sf);
663 Double_t sinNew = sf*ca - cf*sa;
664 if(TMath::Abs(sinNew) >= maxSnp) return kFALSE;
665 if(!track->Rotate(alphan)) return kFALSE;
667 xpos = track->GetX();
671 //---------------------------------------------------------------------------
672 AliESDVertex* AliVertexerTracks::RemoveTracksFromVertex(AliESDVertex *inVtx,
678 // Removes tracks in trksTree from fit of inVtx
681 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraint")) {
682 printf("ERROR: primary vertex has no constraint: cannot remove tracks");
685 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraintOnlyFitter"))
686 printf("WARNING: result of tracks' removal will be only approximately correct");
689 rv(0,0) = inVtx->GetXv();
690 rv(1,0) = inVtx->GetYv();
691 rv(2,0) = inVtx->GetZv();
694 inVtx->GetCovMatrix(cov);
696 vV(0,1) = cov[1]; vV(1,0) = cov[1];
698 vV(0,2) = cov[3]; vV(2,0) = cov[3];
699 vV(1,2) = cov[4]; vV(2,1) = cov[4];
702 TMatrixD sumWi(TMatrixD::kInverted,vV);
703 TMatrixD sumWiri(sumWi,TMatrixD::kMult,rv);
705 Int_t nUsedTrks = inVtx->GetNIndices();
706 Double_t chi2 = inVtx->GetChi2();
708 AliExternalTrackParam *track = 0;
709 Int_t ntrks = (Int_t)trkArray->GetEntriesFast();
710 for(Int_t i=0;i<ntrks;i++) {
711 track = (AliExternalTrackParam*)trkArray->At(i);
712 if(!inVtx->UsesTrack(id[i])) {
713 printf("track %d was not used in vertex fit",id[i]);
716 Double_t alpha = track->GetAlpha();
717 Double_t xl = diamondxy[0]*TMath::Cos(alpha)+diamondxy[1]*TMath::Sin(alpha);
718 track->PropagateTo(xl,GetFieldkG());
719 // vector of track global coordinates
721 // covariance matrix of ri
724 // get space point from track
725 if(!TrackToPoint(track,ri,wWi)) continue;
727 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
733 TMatrixD deltar = rv; deltar -= ri;
734 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
735 Double_t chi2i = deltar(0,0)*wWideltar(0,0)+
736 deltar(1,0)*wWideltar(1,0)+
737 deltar(2,0)*wWideltar(2,0);
738 // remove from total chi2
743 printf("Trying to remove too many tracks!");
751 // new inverted of weights matrix
752 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
754 // new position of primary vertex
755 rvnew.Mult(vVnew,sumWiri);
757 Double_t position[3];
758 position[0] = rvnew(0,0);
759 position[1] = rvnew(1,0);
760 position[2] = rvnew(2,0);
768 // store data in the vertex object
769 AliESDVertex *outVtx = new AliESDVertex(position,cov,chi2,nUsedTrks);
770 outVtx->SetTitle(inVtx->GetTitle());
771 UShort_t *inindices = inVtx->GetIndices();
772 Int_t nIndices = nUsedTrks;
773 UShort_t *outindices = new UShort_t[nIndices];
775 for(Int_t k=0; k<inVtx->GetNIndices(); k++) {
776 Bool_t copyindex=kTRUE;
777 for(Int_t l=0; l<ntrks; l++) {
778 if(inindices[k]==id[l]) copyindex=kFALSE;
781 outindices[j] = inindices[k]; j++;
784 outVtx->SetIndices(nIndices,outindices);
785 delete [] outindices;
788 printf("Vertex before removing tracks:");
789 inVtx->PrintStatus();
790 inVtx->PrintIndices();
791 printf("Vertex after removing tracks:");
792 outVtx->PrintStatus();
793 outVtx->PrintIndices();
798 //---------------------------------------------------------------------------
799 void AliVertexerTracks::SetCuts(Double_t *cuts)
805 SetDCAcutIter0(cuts[1]);
807 if(fMode==0 && cuts[3]<0) SetITSrefitNotRequired();
808 SetMinClusters((Int_t)(TMath::Abs(cuts[3])));
809 SetMinTracks((Int_t)(cuts[4]));
810 SetNSigmad0(cuts[5]);
811 SetMinDetFitter(cuts[6]);
813 SetFiducialRZ(cuts[8],cuts[9]);
817 //---------------------------------------------------------------------------
818 void AliVertexerTracks::SetITSMode(Double_t dcacut,
819 Double_t dcacutIter0,
824 Double_t mindetfitter,
830 // Cut values for ITS mode
834 SetITSrefitRequired();
836 SetITSrefitNotRequired();
839 SetDCAcutIter0(dcacutIter0);
841 SetMinClusters(TMath::Abs(minCls));
842 SetMinTracks(mintrks);
844 SetMinDetFitter(mindetfitter);
846 SetFiducialRZ(fidR,fidZ);
850 //---------------------------------------------------------------------------
851 void AliVertexerTracks::SetTPCMode(Double_t dcacut,
852 Double_t dcacutIter0,
857 Double_t mindetfitter,
863 // Cut values for TPC mode
866 SetITSrefitNotRequired();
868 SetDCAcutIter0(dcacutIter0);
870 SetMinClusters(minCls);
871 SetMinTracks(mintrks);
873 SetMinDetFitter(mindetfitter);
875 SetFiducialRZ(fidR,fidZ);
879 //---------------------------------------------------------------------------
880 void AliVertexerTracks::SetSkipTracks(Int_t n,Int_t *skipped)
883 // Mark the tracks not to be used in the vertex reconstruction.
884 // Tracks are identified by AliESDtrack::GetID()
886 fNTrksToSkip = n; fTrksToSkip = new Int_t[n];
887 for(Int_t i=0;i<n;i++) fTrksToSkip[i] = skipped[i];
890 //---------------------------------------------------------------------------
891 void AliVertexerTracks::SetVtxStart(AliESDVertex *vtx)
894 // Set initial vertex knowledge
896 vtx->GetXYZ(fNominalPos);
897 vtx->GetCovMatrix(fNominalCov);
901 //---------------------------------------------------------------------------
902 void AliVertexerTracks::StrLinVertexFinderMinDist(Int_t optUseWeights)
904 AliExternalTrackParam *track1;
905 const Int_t knacc = (Int_t)fTrkArraySel.GetEntriesFast();
906 static TClonesArray linarray("AliStrLine",knacc);
907 for(Int_t i=0; i<knacc; i++){
908 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
909 Double_t alpha=track1->GetAlpha();
910 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
911 Double_t pos[3],dir[3],sigmasq[3];
912 track1->GetXYZAt(mindist,GetFieldkG(),pos);
913 track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
914 sigmasq[0]=TMath::Sin(alpha)*TMath::Sin(alpha)*track1->GetSigmaY2();
915 sigmasq[1]=TMath::Cos(alpha)*TMath::Cos(alpha)*track1->GetSigmaY2();
916 sigmasq[2]=track1->GetSigmaZ2();
919 if(!TrackToPoint(track1,ri,wWi)) continue;
922 for(Int_t ia=0;ia<3;ia++){
923 for(Int_t ib=0;ib<3;ib++){
924 wmat[iel]=wWi(ia,ib);
928 new(linarray[i]) AliStrLine(pos,sigmasq,wmat,dir);
930 fVert=TrackletVertexFinder(&linarray,optUseWeights);
933 //---------------------------------------------------------------------------
934 AliESDVertex AliVertexerTracks::TrackletVertexFinder(TClonesArray *lines, Int_t optUseWeights)
936 // Calculate the point at minimum distance to prepared tracks
938 const Int_t knacc = (Int_t)lines->GetEntriesFast();
939 Double_t initPos[3]={0.,0.,0.};
941 Double_t (*vectP0)[3]=new Double_t [knacc][3];
942 Double_t (*vectP1)[3]=new Double_t [knacc][3];
945 Double_t dsum[3]={0,0,0};
947 for(Int_t i=0;i<3;i++){
948 for(Int_t j=0;j<3;j++){
954 for(Int_t i=0; i<knacc; i++){
955 AliStrLine* line1 = (AliStrLine*)lines->At(i);
956 Double_t p0[3],cd[3],sigmasq[3];
960 line1->GetSigma2P0(sigmasq);
961 line1->GetWMatrix(wmat);
964 for(Int_t ia=0;ia<3;ia++){
965 for(Int_t ib=0;ib<3;ib++){
966 wWi(ia,ib)=wmat[iel];
973 Double_t p1[3]={p0[0]+cd[0],p0[1]+cd[1],p0[2]+cd[2]};
983 if(optUseWeights==0)GetStrLinDerivMatrix(p0,p1,matr,dknow);
984 else GetStrLinDerivMatrix(p0,p1,sigmasq,matr,dknow);
987 for(Int_t iii=0;iii<3;iii++){
988 dsum[iii]+=dknow[iii];
989 for(Int_t lj=0;lj<3;lj++) sum[iii][lj]+=matr[iii][lj];
993 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
994 Double_t covmatrix[6];
995 covmatrix[0] = invsumWi(0,0);
996 covmatrix[1] = invsumWi(0,1);
997 covmatrix[2] = invsumWi(1,1);
998 covmatrix[3] = invsumWi(0,2);
999 covmatrix[4] = invsumWi(1,2);
1000 covmatrix[5] = invsumWi(2,2);
1002 Double_t vett[3][3];
1003 Double_t det=GetDeterminant3X3(sum);
1007 for(Int_t zz=0;zz<3;zz++){
1008 for(Int_t ww=0;ww<3;ww++){
1009 for(Int_t kk=0;kk<3;kk++) vett[ww][kk]=sum[ww][kk];
1011 for(Int_t kk=0;kk<3;kk++) vett[kk][zz]=dsum[kk];
1012 initPos[zz]=GetDeterminant3X3(vett)/det;
1016 for(Int_t i=0; i<knacc; i++){
1017 Double_t p0[3]={0,0,0},p1[3]={0,0,0};
1018 for(Int_t ii=0;ii<3;ii++){
1019 p0[ii]=vectP0[i][ii];
1020 p1[ii]=vectP1[i][ii];
1022 sigma+=GetStrLinMinDist(p0,p1,initPos);
1025 if(sigma>0.) {sigma=TMath::Sqrt(sigma);}else{sigma=999;}
1029 AliESDVertex theVert(initPos,covmatrix,99999.,knacc);
1030 theVert.SetDispersion(sigma);
1035 //---------------------------------------------------------------------------
1036 Bool_t AliVertexerTracks::TrackToPoint(AliExternalTrackParam *t,
1037 TMatrixD &ri,TMatrixD &wWi,
1038 Bool_t uUi3by3) const
1041 // Extract from the AliExternalTrackParam the global coordinates ri and covariance matrix
1042 // wWi of the space point that it represents (to be used in VertexFitter())
1046 Double_t rotAngle = t->GetAlpha();
1047 if(rotAngle<0.) rotAngle += 2.*TMath::Pi();
1048 Double_t cosRot = TMath::Cos(rotAngle);
1049 Double_t sinRot = TMath::Sin(rotAngle);
1051 ri(0,0) = t->GetX()*cosRot-t->GetY()*sinRot;
1052 ri(1,0) = t->GetX()*sinRot+t->GetY()*cosRot;
1053 ri(2,0) = t->GetZ();
1058 // matrix to go from global (x,y,z) to local (y,z);
1067 // covariance matrix of local (y,z) - inverted
1069 uUi(0,0) = t->GetSigmaY2();
1070 uUi(0,1) = t->GetSigmaZY();
1071 uUi(1,0) = t->GetSigmaZY();
1072 uUi(1,1) = t->GetSigmaZ2();
1074 //printf(" %f %f",uUi(0,0),uUi(0,1));
1075 //printf(" %f %f",uUi(1,0),uUi(1,1));
1077 if(uUi.Determinant() <= 0.) return kFALSE;
1078 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
1080 // weights matrix: wWi = qQiT * uUiInv * qQi
1081 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
1082 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
1085 if(fVert.GetNContributors()<1) AliFatal("Vertex from finder is empty");
1086 // matrix to go from global (x,y,z) to local (x,y,z);
1098 // covariance of fVert along the track
1099 Double_t p[3],pt,ptot;
1101 pt = TMath::Sqrt(p[0]*p[0]+p[1]*p[1]);
1102 ptot = TMath::Sqrt(pt*pt+p[2]*p[2]);
1103 Double_t cphi = p[0]/pt; //cos(phi)=px/pt
1104 Double_t sphi = p[1]/pt; //sin(phi)=py/pt
1105 Double_t clambda = pt/ptot; //cos(lambda)=pt/ptot
1106 Double_t slambda = p[2]/ptot; //sin(lambda)=pz/ptot
1107 Double_t covfVert[6];
1108 fVert.GetCovMatrix(covfVert);
1109 Double_t covfVertalongt =
1110 covfVert[0]*cphi*cphi*clambda*clambda
1111 +covfVert[1]*2.*cphi*sphi*clambda*clambda
1112 +covfVert[3]*2.*cphi*clambda*slambda
1113 +covfVert[2]*sphi*sphi*clambda*clambda
1114 +covfVert[4]*2.*sphi*clambda*slambda
1115 +covfVert[5]*slambda*slambda;
1116 // covariance matrix of local (x,y,z) - inverted
1118 uUi(0,0) = covfVertalongt * fnSigmaForUi00 * fnSigmaForUi00;
1119 AliDebug(1,Form("=====> sqrtUi00 cm %f",TMath::Sqrt(uUi(0,0))));
1123 uUi(1,1) = t->GetSigmaY2();
1124 uUi(1,2) = t->GetSigmaZY();
1126 uUi(2,1) = t->GetSigmaZY();
1127 uUi(2,2) = t->GetSigmaZ2();
1128 //printf(" Ui :\n");
1129 //printf(" %f %f\n",uUi(0,0),uUi(0,1));
1130 //printf(" %f %f\n",uUi(1,0),uUi(1,1));
1132 if(uUi.Determinant() <= 0.) return kFALSE;
1133 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
1135 // weights matrix: wWi = qQiT * uUiInv * qQi
1136 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
1137 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
1144 //---------------------------------------------------------------------------
1145 void AliVertexerTracks::TooFewTracks()
1148 // When the number of tracks is < fMinTracks,
1149 // deal with vertices not found and prepare to exit
1151 AliDebug(1,"TooFewTracks");
1153 Double_t pos[3],err[3];
1154 pos[0] = fNominalPos[0];
1155 err[0] = TMath::Sqrt(fNominalCov[0]);
1156 pos[1] = fNominalPos[1];
1157 err[1] = TMath::Sqrt(fNominalCov[2]);
1158 pos[2] = fNominalPos[2];
1159 err[2] = TMath::Sqrt(fNominalCov[5]);
1160 Int_t ncontr = (err[0]>1. ? -1 : -3);
1161 if(fCurrentVertex) { delete fCurrentVertex; fCurrentVertex=0; }
1162 fCurrentVertex = new AliESDVertex(pos,err);
1163 fCurrentVertex->SetNContributors(ncontr);
1166 fCurrentVertex->SetTitle("VertexerTracksWithConstraint");
1168 fCurrentVertex->SetTitle("VertexerTracksNoConstraint");
1171 if(!fTrkArraySel.IsEmpty()) fTrkArraySel.Delete();
1172 if(fIdSel) {delete [] fIdSel; fIdSel=NULL;}
1173 if(fTrksToSkip) {delete [] fTrksToSkip; fTrksToSkip=NULL;}
1177 //---------------------------------------------------------------------------
1178 void AliVertexerTracks::VertexFinder(Int_t optUseWeights)
1181 // Get estimate of vertex position in (x,y) from tracks DCA
1183 Double_t initPos[3];
1185 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
1186 Int_t nacc = (Int_t)fTrkArraySel.GetEntriesFast();
1187 Double_t aver[3]={0.,0.,0.};
1188 Double_t aversq[3]={0.,0.,0.};
1189 Double_t sigmasq[3]={0.,0.,0.};
1192 AliExternalTrackParam *track1;
1193 AliExternalTrackParam *track2;
1194 Double_t pos[3],dir[3];
1195 Double_t alpha,mindist;
1197 for(Int_t i=0; i<nacc; i++){
1198 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
1199 alpha=track1->GetAlpha();
1200 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1201 track1->GetXYZAt(mindist,GetFieldkG(),pos);
1202 track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
1203 AliStrLine *line1 = new AliStrLine(pos,dir);
1205 // AliStrLine *line1 = new AliStrLine();
1206 // track1->ApproximateHelixWithLine(mindist,GetFieldkG(),line1);
1208 for(Int_t j=i+1; j<nacc; j++){
1209 track2 = (AliExternalTrackParam*)fTrkArraySel.At(j);
1210 alpha=track2->GetAlpha();
1211 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1212 track2->GetXYZAt(mindist,GetFieldkG(),pos);
1213 track2->GetPxPyPzAt(mindist,GetFieldkG(),dir);
1214 AliStrLine *line2 = new AliStrLine(pos,dir);
1215 // AliStrLine *line2 = new AliStrLine();
1216 // track2->ApproximateHelixWithLine(mindist,GetFieldkG(),line2);
1217 Double_t distCA=line2->GetDCA(line1);
1218 //printf("%d %d %f\n",i,j,distCA);
1219 if(fDCAcut<=0 || (fDCAcut>0&&distCA<fDCAcut)){
1220 Double_t pnt1[3],pnt2[3],crosspoint[3];
1222 if(optUseWeights<=0){
1223 Int_t retcode = line2->Cross(line1,crosspoint);
1226 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
1227 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1230 if(optUseWeights>0){
1231 Int_t retcode = line1->CrossPoints(line2,pnt1,pnt2);
1234 alpha=track1->GetAlpha();
1235 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
1236 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
1237 alpha=track2->GetAlpha();
1238 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
1239 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
1240 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
1241 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
1242 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
1243 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
1244 crosspoint[0]=wx1*pnt1[0] + wx2*pnt2[0];
1245 crosspoint[1]=wy1*pnt1[1] + wy2*pnt2[1];
1246 crosspoint[2]=wz1*pnt1[2] + wz2*pnt2[2];
1249 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
1250 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1259 for(Int_t jj=0;jj<3;jj++){
1260 initPos[jj] = aver[jj]/ncombi;
1261 //printf("%f\n",initPos[jj]);
1263 sigmasq[jj]=aversq[jj]-initPos[jj]*initPos[jj];
1266 sigma=TMath::Sqrt(TMath::Abs(sigma));
1269 Warning("VertexFinder","Finder did not succed");
1272 fVert.SetXYZ(initPos);
1273 fVert.SetDispersion(sigma);
1274 fVert.SetNContributors(ncombi);
1276 //---------------------------------------------------------------------------
1277 void AliVertexerTracks::VertexFitter()
1280 // The optimal estimate of the vertex position is given by a "weighted
1281 // average of tracks positions".
1282 // Original method: V. Karimaki, CMS Note 97/0051
1284 Bool_t useConstraint = fConstraint;
1285 Double_t initPos[3];
1287 fVert.GetXYZ(initPos);
1289 initPos[0]=fNominalPos[0];
1290 initPos[1]=fNominalPos[1];
1291 initPos[2]=fNominalPos[2];
1294 Int_t nTrksSel = (Int_t)fTrkArraySel.GetEntries();
1295 if(nTrksSel==1) useConstraint=kTRUE;
1296 AliDebug(1,"--- VertexFitter(): start");
1297 AliDebug(1,Form(" Number of tracks in array: %d\n",nTrksSel));
1298 AliDebug(1,Form(" Minimum # tracks required in fit: %d\n",fMinTracks));
1299 AliDebug(1,Form(" Vertex position after finder: %f,%f,%f\n",initPos[0],initPos[1],initPos[2]));
1300 if(useConstraint) AliDebug(1,Form(" This vertex will be used in fit: (%f+-%f,%f+-%f)\n",fNominalPos[0],TMath::Sqrt(fNominalCov[0]),fNominalPos[1],TMath::Sqrt(fNominalCov[2])));
1302 // special treatment for few-tracks fits (e.g. secondary vertices)
1303 Bool_t uUi3by3 = kFALSE; if(nTrksSel<5 && !useConstraint) uUi3by3 = kTRUE;
1308 rv(0,0) = initPos[0];
1309 rv(1,0) = initPos[1];
1311 Double_t xlStart,alpha;
1313 Double_t chi2,chi2i,chi2b;
1314 AliExternalTrackParam *t = 0;
1317 // initial vertex covariance matrix
1319 vVb(0,0) = fNominalCov[0];
1320 vVb(0,1) = fNominalCov[1];
1322 vVb(1,0) = fNominalCov[1];
1323 vVb(1,1) = fNominalCov[2];
1327 vVb(2,2) = fNominalCov[5];
1328 TMatrixD vVbInv(TMatrixD::kInverted,vVb);
1330 rb(0,0) = fNominalPos[0];
1331 rb(1,0) = fNominalPos[1];
1332 rb(2,0) = fNominalPos[2];
1333 TMatrixD vVbInvrb(vVbInv,TMatrixD::kMult,rb);
1337 // 1st - estimate of vtx using all tracks
1338 // 2nd - estimate of global chi2
1339 for(step=0; step<2; step++) {
1340 AliDebug(1,Form(" step = %d\n",step));
1344 if(step==1) { initPos[0]=rv(0,0); initPos[0]=rv(1,0); }
1346 TMatrixD sumWiri(3,1);
1347 TMatrixD sumWi(3,3);
1348 for(i=0; i<3; i++) {
1350 for(j=0; j<3; j++) sumWi(j,i) = 0.;
1353 // mean vertex constraint
1356 sumWiri(i,0) += vVbInvrb(i,0);
1357 for(k=0;k<3;k++) sumWi(i,k) += vVbInv(i,k);
1360 TMatrixD deltar = rv; deltar -= rb;
1361 TMatrixD vVbInvdeltar(vVbInv,TMatrixD::kMult,deltar);
1362 chi2b = deltar(0,0)*vVbInvdeltar(0,0)+
1363 deltar(1,0)*vVbInvdeltar(1,0)+
1364 deltar(2,0)*vVbInvdeltar(2,0);
1369 for(k=0; k<nTrksSel; k++) {
1370 // get track from track array
1371 t = (AliExternalTrackParam*)fTrkArraySel.At(k);
1372 alpha = t->GetAlpha();
1373 xlStart = initPos[0]*TMath::Cos(alpha)+initPos[1]*TMath::Sin(alpha);
1374 // to vtxSeed (from finder)
1375 t->PropagateTo(xlStart,GetFieldkG());
1377 // vector of track global coordinates
1379 // covariance matrix of ri
1382 // get space point from track
1383 if(!TrackToPoint(t,ri,wWi,uUi3by3)) continue;
1384 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
1387 TMatrixD deltar = rv; deltar -= ri;
1388 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
1389 chi2i = deltar(0,0)*wWideltar(0,0)+
1390 deltar(1,0)*wWideltar(1,0)+
1391 deltar(2,0)*wWideltar(2,0);
1393 // add to total chi2
1400 } // end loop on tracks
1402 if(nTrksUsed < fMinTracks) {
1407 Double_t determinant = sumWi.Determinant();
1408 if(determinant < fMinDetFitter) {
1409 AliDebug(1,Form("det(V) = %f (<%f)\n",determinant,fMinDetFitter));
1415 // inverted of weights matrix
1416 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
1418 // position of primary vertex
1419 rv.Mult(vV,sumWiri);
1421 } // end loop on the 2 steps
1428 Double_t position[3];
1429 position[0] = rv(0,0);
1430 position[1] = rv(1,0);
1431 position[2] = rv(2,0);
1432 Double_t covmatrix[6];
1433 covmatrix[0] = vV(0,0);
1434 covmatrix[1] = vV(0,1);
1435 covmatrix[2] = vV(1,1);
1436 covmatrix[3] = vV(0,2);
1437 covmatrix[4] = vV(1,2);
1438 covmatrix[5] = vV(2,2);
1440 // for correct chi2/ndf, count constraint as additional "track"
1441 if(fConstraint) nTrksUsed++;
1442 // store data in the vertex object
1443 if(fCurrentVertex) { delete fCurrentVertex; fCurrentVertex=0; }
1444 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nTrksUsed);
1446 AliDebug(1," Vertex after fit:");
1447 AliDebug(1,Form("xyz: %f %f %f; nc %d",fCurrentVertex->GetXv(),fCurrentVertex->GetYv(),fCurrentVertex->GetZv(),fCurrentVertex->GetNContributors()));
1448 AliDebug(1,"--- VertexFitter(): finish\n");
1453 //----------------------------------------------------------------------------
1454 AliESDVertex* AliVertexerTracks::VertexForSelectedTracks(TObjArray *trkArray,
1456 Bool_t optUseFitter,
1457 Bool_t optPropagate)
1460 // Return vertex from tracks (AliExternalTrackParam) in array
1465 // get tracks and propagate them to initial vertex position
1466 fIdSel = new UShort_t[(Int_t)trkArray->GetEntriesFast()];
1467 Int_t nTrksSel = PrepareTracks(*trkArray,id,0);
1468 if(nTrksSel < TMath::Max(2,fMinTracks)) {
1470 return fCurrentVertex;
1475 case 1: StrLinVertexFinderMinDist(1); break;
1476 case 2: StrLinVertexFinderMinDist(0); break;
1477 case 3: HelixVertexFinder(); break;
1478 case 4: VertexFinder(1); break;
1479 case 5: VertexFinder(0); break;
1480 default: printf("Wrong algorithm\n"); break;
1482 AliDebug(1," Vertex finding completed\n");
1488 Double_t position[3]={fVert.GetXv(),fVert.GetYv(),fVert.GetZv()};
1489 Double_t covmatrix[6];
1490 fVert.GetCovMatrix(covmatrix);
1491 Double_t chi2=99999.;
1492 Int_t nTrksUsed=fVert.GetNContributors();
1493 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nTrksUsed);
1495 fCurrentVertex->SetDispersion(fVert.GetDispersion());
1498 // set indices of used tracks and propagate track to found vertex
1499 UShort_t *indices = 0;
1500 Double_t d0z0[2],covd0z0[3];
1501 AliExternalTrackParam *t = 0;
1502 if(fCurrentVertex->GetNContributors()>0) {
1503 indices = new UShort_t[fCurrentVertex->GetNContributors()];
1504 for(Int_t jj=0; jj<(Int_t)fTrkArraySel.GetEntriesFast(); jj++) {
1505 indices[jj] = fIdSel[jj];
1506 t = (AliExternalTrackParam*)fTrkArraySel.At(jj);
1507 if(optPropagate && optUseFitter) {
1508 if(TMath::Sqrt(fCurrentVertex->GetXv()*fCurrentVertex->GetXv()+fCurrentVertex->GetYv()*fCurrentVertex->GetYv())<3.) {
1509 t->PropagateToDCA(fCurrentVertex,GetFieldkG(),100.,d0z0,covd0z0);
1510 AliDebug(1,Form("Track %d propagated to found vertex",jj));
1512 AliWarning("Found vertex outside beam pipe!");
1516 fCurrentVertex->SetIndices(fCurrentVertex->GetNContributors(),indices);
1520 delete [] indices; indices=NULL;
1521 delete [] fIdSel; fIdSel=NULL;
1522 fTrkArraySel.Delete();
1524 return fCurrentVertex;
1526 //----------------------------------------------------------------------------
1527 AliESDVertex* AliVertexerTracks::VertexForSelectedESDTracks(TObjArray *trkArray,
1528 Bool_t optUseFitter,
1529 Bool_t optPropagate)
1532 // Return vertex from array of ESD tracks
1535 Int_t nTrks = (Int_t)trkArray->GetEntriesFast();
1536 UShort_t *id = new UShort_t[nTrks];
1538 AliESDtrack *esdt = 0;
1539 for(Int_t i=0; i<nTrks; i++){
1540 esdt = (AliESDtrack*)trkArray->At(i);
1541 id[i] = (UShort_t)esdt->GetID();
1544 VertexForSelectedTracks(trkArray,id,optUseFitter,optPropagate);
1546 delete [] id; id=NULL;
1548 return fCurrentVertex;
1550 //--------------------------------------------------------------------------