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);
166 // check tracks to skip
167 Bool_t skipThis = kFALSE;
168 for(Int_t j=0; j<fNTrksToSkip; j++) {
169 if(track->GetID()==fTrksToSkip[j]) {
170 AliDebug(1,Form("skipping track: %d",i));
174 if(skipThis) continue;
176 if(!inputAOD) { // ESD
177 AliESDtrack* esdt = (AliESDtrack*)track;
178 if(esdt->GetNcls(fMode) < fMinClusters) continue;
179 if(fMode==0) { // ITS mode
180 if(fITSrefit && !(esdt->GetStatus()&AliESDtrack::kITSrefit)) continue;
181 Double_t x,p[5],cov[15];
182 esdt->GetExternalParameters(x,p);
183 esdt->GetExternalCovariance(cov);
184 t = new AliExternalTrackParam(x,esdt->GetAlpha(),p,cov);
185 } else if(fMode==1) { // TPC mode
186 t = (AliExternalTrackParam*)esdt->GetTPCInnerParam();
188 Double_t radius = 2.8; //something less than the beam pipe radius
189 if(!PropagateTrackTo(t,radius)) continue;
191 } else { // AOD (only ITS mode)
193 for(Int_t l=0;l<6;l++) if(TESTBIT(track->GetITSClusterMap(),l)) ncls0++;
194 if(ncls0 < fMinClusters) continue;
195 t = new AliExternalTrackParam(track);
197 trkArrayOrig.AddLast(t);
198 idOrig[nTrksOrig]=(UShort_t)track->GetID();
200 } // end loop on tracks
202 // call method that will reconstruct the vertex
203 FindPrimaryVertex(&trkArrayOrig,idOrig);
205 if(fMode==0) trkArrayOrig.Delete();
206 delete [] idOrig; idOrig=NULL;
209 f->Close(); delete f; f = NULL;
210 gSystem->Unlink("VertexerTracks.root");
214 return fCurrentVertex;
216 //----------------------------------------------------------------------------
217 AliESDVertex* AliVertexerTracks::FindPrimaryVertex(TObjArray *trkArrayOrig,
221 // Primary vertex using the AliExternalTrackParam's in the TObjArray.
222 // idOrig must contain the track IDs from AliESDtrack::GetID()
224 // 1st with 5*fNSigma*sigma cut w.r.t. to initial vertex
225 // + cut on sqrt(d0d0+z0z0) if fConstraint=kFALSE
226 // 2nd with fNSigma*sigma cut w.r.t. to vertex found in 1st iteration)
230 // accept 1-track case only if constraint is available
231 if(!fConstraint && fMinTracks==1) fMinTracks=2;
233 // read tracks from array
234 Int_t nTrksOrig = (Int_t)trkArrayOrig->GetEntriesFast();
235 AliDebug(1,Form("Initial number of tracks: %d",nTrksOrig));
236 if(nTrksOrig<fMinTracks) {
237 AliDebug(1,"TooFewTracks");
239 return fCurrentVertex;
242 // If fConstraint=kFALSE
243 // run VertexFinder(1) to get rough estimate of initVertex (x,y)
245 // fill fTrkArraySel, for VertexFinder()
246 fIdSel = new UShort_t[nTrksOrig];
247 PrepareTracks(*trkArrayOrig,idOrig,0);
248 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
249 Double_t cutsave = fDCAcut;
250 fDCAcut = fDCAcutIter0;
251 VertexFinder(1); // using weights, cutting dca < fDCAcutIter0
253 if(fVert.GetNContributors()>0) {
254 fVert.GetXYZ(fNominalPos);
255 fNominalPos[0] = fVert.GetXv();
256 fNominalPos[1] = fVert.GetYv();
257 fNominalPos[2] = fVert.GetZv();
258 AliDebug(1,Form("No mean vertex: VertexFinder gives (%f, %f, %f)",fNominalPos[0],fNominalPos[1],fNominalPos[2]));
263 AliDebug(1,"No mean vertex and VertexFinder failed");
270 // propagate tracks to fNominalPos vertex
272 // if(constraint) reject for |d0|>5*fNSigma*sigma w.r.t. fNominal... vertex
273 // else reject for |d0|\oplus|z0| > 5 mm w.r.t. fNominal... vertex
275 // propagate tracks to best between initVertex and fCurrentVertex
276 // preselect tracks (reject for |d0|>fNSigma*sigma w.r.t. best
277 // between initVertex and fCurrentVertex)
278 for(Int_t iter=1; iter<=2; iter++) {
279 if(fOnlyFitter && iter==1) continue;
280 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
281 fIdSel = new UShort_t[nTrksOrig];
282 Int_t nTrksSel = PrepareTracks(*trkArrayOrig,idOrig,iter);
283 AliDebug(1,Form("N tracks selected in iteration %d: %d",iter,nTrksSel));
284 if(nTrksSel < fMinTracks) {
286 return fCurrentVertex;
292 AliDebug(1,"Just one track");
293 OneTrackVertFinder();
296 case 1: StrLinVertexFinderMinDist(1); break;
297 case 2: StrLinVertexFinderMinDist(0); break;
298 case 3: HelixVertexFinder(); break;
299 case 4: VertexFinder(1); break;
300 case 5: VertexFinder(0); break;
301 default: printf("Wrong algorithm"); break;
304 AliDebug(1," Vertex finding completed");
309 } // end loop on the two iterations
312 // set indices of used tracks
313 UShort_t *indices = 0;
314 if(fCurrentVertex->GetNContributors()>0) {
315 Int_t nIndices = (Int_t)fTrkArraySel.GetEntriesFast();
316 indices = new UShort_t[nIndices];
317 for(Int_t jj=0; jj<nIndices; jj++)
318 indices[jj] = fIdSel[jj];
319 fCurrentVertex->SetIndices(nIndices,indices);
321 delete [] indices; indices=NULL;
325 TString title="VertexerTracksNoConstraint";
327 title="VertexerTracksWithConstraint";
328 if(fOnlyFitter) title.Append("OnlyFitter");
330 fCurrentVertex->SetTitle(title.Data());
333 AliDebug(1,Form("xyz: %f %f %f; nc %d",fCurrentVertex->GetXv(),fCurrentVertex->GetYv(),fCurrentVertex->GetZv(),fCurrentVertex->GetNContributors()));
336 delete [] fIdSel; fIdSel=NULL;
337 fTrkArraySel.Delete();
338 if(fTrksToSkip) { delete [] fTrksToSkip; fTrksToSkip=NULL; }
341 return fCurrentVertex;
343 //------------------------------------------------------------------------
344 Double_t AliVertexerTracks::GetDeterminant3X3(Double_t matr[][3])
347 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];
350 //-------------------------------------------------------------------------
351 void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t (*m)[3],Double_t *d)
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 kk=x12*x12+y12*y12+z12*z12;
358 m[0][0]=2-2/kk*x12*x12;
359 m[0][1]=-2/kk*x12*y12;
360 m[0][2]=-2/kk*x12*z12;
361 m[1][0]=-2/kk*x12*y12;
362 m[1][1]=2-2/kk*y12*y12;
363 m[1][2]=-2/kk*y12*z12;
364 m[2][0]=-2/kk*x12*z12;
366 m[2][2]=2-2/kk*z12*z12;
367 d[0]=2*p0[0]-2/kk*p0[0]*x12*x12-2/kk*p0[2]*x12*z12-2/kk*p0[1]*x12*y12;
368 d[1]=2*p0[1]-2/kk*p0[1]*y12*y12-2/kk*p0[0]*x12*y12-2/kk*p0[2]*z12*y12;
369 d[2]=2*p0[2]-2/kk*p0[2]*z12*z12-2/kk*p0[0]*x12*z12-2/kk*p0[1]*z12*y12;
372 //--------------------------------------------------------------------------
373 void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t *sigmasq,Double_t (*m)[3],Double_t *d)
376 Double_t x12=p1[0]-p0[0];
377 Double_t y12=p1[1]-p0[1];
378 Double_t z12=p1[2]-p0[2];
380 Double_t den= x12*x12*sigmasq[1]*sigmasq[2]+y12*y12*sigmasq[0]*sigmasq[2]+z12*z12*sigmasq[0]*sigmasq[1];
382 Double_t kk= 2*(x12*x12/sigmasq[0]+y12*y12/sigmasq[1]+z12*z12/sigmasq[2]);
385 cc[0]=-x12/sigmasq[0];
386 cc[1]=-y12/sigmasq[1];
387 cc[2]=-z12/sigmasq[2];
389 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;
391 Double_t ss= -p0[0]*cc[0]-p0[1]*cc[1]-p0[2]*cc[2];
394 aa[0]=x12*sigmasq[1]*sigmasq[2]/den;
395 aa[1]=y12*sigmasq[0]*sigmasq[2]/den;
396 aa[2]=z12*sigmasq[0]*sigmasq[1]/den;
398 m[0][0]=aa[0]*(aa[0]*kk+2*cc[0])+2*cc[0]*aa[0]+2/sigmasq[0];
399 m[0][1]=aa[1]*(aa[0]*kk+2*cc[0])+2*cc[1]*aa[0];
400 m[0][2]=aa[2]*(aa[0]*kk+2*cc[0])+2*cc[2]*aa[0];
402 m[1][0]=aa[0]*(aa[1]*kk+2*cc[1])+2*cc[0]*aa[1];
403 m[1][1]=aa[1]*(aa[1]*kk+2*cc[1])+2*cc[1]*aa[1]+2/sigmasq[1];
404 m[1][2]=aa[2]*(aa[1]*kk+2*cc[1])+2*cc[2]*aa[1];
406 m[2][0]=aa[0]*(aa[2]*kk+2*cc[2])+2*cc[0]*aa[2];
407 m[2][1]=aa[1]*(aa[2]*kk+2*cc[2])+2*cc[1]*aa[2];
408 m[2][2]=aa[2]*(aa[2]*kk+2*cc[2])+2*cc[2]*aa[2]+2/sigmasq[2];
410 d[0]=-ww*(aa[0]*kk+2*cc[0])-2*ss*aa[0]+2*p0[0]/sigmasq[0];
411 d[1]=-ww*(aa[1]*kk+2*cc[1])-2*ss*aa[1]+2*p0[1]/sigmasq[1];
412 d[2]=-ww*(aa[2]*kk+2*cc[2])-2*ss*aa[2]+2*p0[2]/sigmasq[2];
415 //--------------------------------------------------------------------------
416 Double_t AliVertexerTracks::GetStrLinMinDist(Double_t *p0,Double_t *p1,Double_t *x0)
419 Double_t x12=p0[0]-p1[0];
420 Double_t y12=p0[1]-p1[1];
421 Double_t z12=p0[2]-p1[2];
422 Double_t x10=p0[0]-x0[0];
423 Double_t y10=p0[1]-x0[1];
424 Double_t z10=p0[2]-x0[2];
425 // 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);
426 return ((y10*z12-z10*y12)*(y10*z12-z10*y12)+
427 (z10*x12-x10*z12)*(z10*x12-x10*z12)+
428 (x10*y12-y10*x12)*(x10*y12-y10*x12))
429 /(x12*x12+y12*y12+z12*z12);
431 //---------------------------------------------------------------------------
432 void AliVertexerTracks::OneTrackVertFinder()
434 // find vertex for events with 1 track, using DCA to nominal beam axis
435 AliDebug(1,Form("Number of prepared tracks =%d - Call OneTrackVertFinder",fTrkArraySel.GetEntries()));
436 AliExternalTrackParam *track1;
437 track1 = (AliExternalTrackParam*)fTrkArraySel.At(0);
438 Double_t alpha=track1->GetAlpha();
439 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
440 Double_t pos[3],dir[3];
441 track1->GetXYZAt(mindist,GetFieldkG(),pos);
442 track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
443 AliStrLine *line1 = new AliStrLine(pos,dir);
444 Double_t p1[3]={fNominalPos[0],fNominalPos[1],0.};
445 Double_t p2[3]={fNominalPos[0],fNominalPos[1],10.};
446 AliStrLine *zeta=new AliStrLine(p1,p2,kTRUE);
447 Double_t crosspoint[3]={0.,0.,0.};
450 Int_t retcode = zeta->Cross(line1,crosspoint);
452 sigma=line1->GetDistFromPoint(crosspoint);
457 fVert.SetXYZ(crosspoint);
458 fVert.SetDispersion(sigma);
459 fVert.SetNContributors(nContrib);
461 //---------------------------------------------------------------------------
462 void AliVertexerTracks::HelixVertexFinder()
464 // Get estimate of vertex position in (x,y) from tracks DCA
469 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
471 Int_t nacc = (Int_t)fTrkArraySel.GetEntriesFast();
473 Double_t aver[3]={0.,0.,0.};
474 Double_t averquad[3]={0.,0.,0.};
475 Double_t sigmaquad[3]={0.,0.,0.};
478 AliExternalTrackParam *track1;
479 AliExternalTrackParam *track2;
482 Double_t alpha, cs, sn;
483 Double_t crosspoint[3];
484 for(Int_t i=0; i<nacc; i++){
485 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
488 for(Int_t j=i+1; j<nacc; j++){
489 track2 = (AliExternalTrackParam*)fTrkArraySel.At(j);
491 distCA=track2->PropagateToDCA(track1,GetFieldkG());
492 if(fDCAcut<=0 ||(fDCAcut>0&&distCA<fDCAcut)){
494 alpha=track1->GetAlpha();
495 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
496 Double_t x1=x*cs - track1->GetY()*sn;
497 Double_t y1=x*sn + track1->GetY()*cs;
498 Double_t z1=track1->GetZ();
500 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
502 alpha=track2->GetAlpha();
503 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
504 Double_t x2=x*cs - track2->GetY()*sn;
505 Double_t y2=x*sn + track2->GetY()*cs;
506 Double_t z2=track2->GetZ();
507 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
508 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
509 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
510 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
511 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
512 crosspoint[0]=wx1*x1 + wx2*x2;
513 crosspoint[1]=wy1*y1 + wy2*y2;
514 crosspoint[2]=wz1*z1 + wz2*z2;
517 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
518 for(Int_t jj=0;jj<3;jj++)averquad[jj]+=(crosspoint[jj]*crosspoint[jj]);
524 for(Int_t jj=0;jj<3;jj++){
525 initPos[jj] = aver[jj]/ncombi;
526 averquad[jj]/=ncombi;
527 sigmaquad[jj]=averquad[jj]-initPos[jj]*initPos[jj];
528 sigma+=sigmaquad[jj];
530 sigma=TMath::Sqrt(TMath::Abs(sigma));
533 Warning("HelixVertexFinder","Finder did not succed");
536 fVert.SetXYZ(initPos);
537 fVert.SetDispersion(sigma);
538 fVert.SetNContributors(ncombi);
540 //----------------------------------------------------------------------------
541 Int_t AliVertexerTracks::PrepareTracks(TObjArray &trkArrayOrig,
546 // Propagate tracks to initial vertex position and store them in a TObjArray
548 AliDebug(1," PrepareTracks()");
550 Int_t nTrksOrig = (Int_t)trkArrayOrig.GetEntriesFast();
553 Double_t sigmaCurr[3];
554 Double_t normdistx,normdisty;
555 Double_t d0z0[2],covd0z0[3];
558 AliESDVertex *initVertex = new AliESDVertex(fNominalPos,fNominalCov,1,1);
560 if(!fTrkArraySel.IsEmpty()) fTrkArraySel.Delete();
562 AliExternalTrackParam *track=0;
565 for(Int_t i=0; i<nTrksOrig; i++) {
566 track = new AliExternalTrackParam(*(AliExternalTrackParam*)trkArrayOrig.At(i));
568 if(TMath::Abs(track->GetTgl())>fMaxTgl) {
569 AliDebug(1,Form(" rejecting track with tgl = %f",track->GetTgl()));
570 delete track; continue;
573 Bool_t propagateOK = kFALSE;
574 // propagate track to vertex
575 if(optImpParCut<2 || fOnlyFitter) { // optImpParCut==1 or 0
576 propagateOK = track->PropagateToDCA(initVertex,GetFieldkG(),100.,d0z0,covd0z0);
577 } else { // optImpParCut==2
578 fCurrentVertex->GetSigmaXYZ(sigmaCurr);
579 normdistx = TMath::Abs(fCurrentVertex->GetXv()-fNominalPos[0])/TMath::Sqrt(sigmaCurr[0]*sigmaCurr[0]+fNominalCov[0]);
580 normdisty = TMath::Abs(fCurrentVertex->GetYv()-fNominalPos[1])/TMath::Sqrt(sigmaCurr[1]*sigmaCurr[1]+fNominalCov[2]);
581 if(normdistx < 3. && normdisty < 3. &&
582 (sigmaCurr[0]+sigmaCurr[1])<(TMath::Sqrt(fNominalCov[0])+TMath::Sqrt(fNominalCov[2]))) {
583 propagateOK = track->PropagateToDCA(fCurrentVertex,GetFieldkG(),100.,d0z0,covd0z0);
585 propagateOK = track->PropagateToDCA(initVertex,GetFieldkG(),100.,d0z0,covd0z0);
590 AliDebug(1," rejected");
591 delete track; continue;
594 sigmad0 = TMath::Sqrt(covd0z0[0]);
595 maxd0rphi = fNSigma*sigmad0;
596 if(optImpParCut==1) maxd0rphi *= 5.;
597 maxd0rphi = TMath::Min(maxd0rphi,fFiducialR);
598 //sigmad0z0 = TMath::Sqrt(covd0z0[0]+covd0z0[2]); // for future improvement
599 //maxd0z0 = 10.*fNSigma*sigmad0z0;
601 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));
604 //---- track selection based on impact parameters ----//
606 // always reject tracks outside fiducial volume
607 if(TMath::Abs(d0z0[0])>fFiducialR || TMath::Abs(d0z0[1])>fFiducialZ) {
608 AliDebug(1," rejected");
609 delete track; continue;
612 // during iterations 1 and 2 , reject tracks with d0rphi > maxd0rphi
613 if(optImpParCut>0 && TMath::Abs(d0z0[0])>maxd0rphi) {
614 AliDebug(1," rejected");
615 delete track; continue;
618 // if fConstraint=kFALSE, during iterations 1 and 2 ||
619 // if fConstraint=kTRUE, during iteration 2,
620 // select tracks with d0oplusz0 < fMaxd0z0
621 if((!fConstraint && optImpParCut>0 && fVert.GetNContributors()>0) ||
622 ( fConstraint && optImpParCut==2)) {
624 TMath::Sqrt(d0z0[0]*d0z0[0]+d0z0[1]*d0z0[1])>fMaxd0z0) {
625 AliDebug(1," rejected");
626 delete track; continue;
630 // track passed all selections
631 fTrkArraySel.AddLast(track);
632 fIdSel[nTrksSel] = idOrig[i];
634 } // end loop on tracks
640 //----------------------------------------------------------------------------
641 Bool_t AliVertexerTracks::PropagateTrackTo(AliExternalTrackParam *track,
643 //----------------------------------------------------------------
644 // COPIED from AliTracker
646 // Propagates the track to the plane X=xk (cm).
648 // Origin: Marian Ivanov, Marian.Ivanov@cern.ch
649 //----------------------------------------------------------------
651 const Double_t kEpsilon = 0.00001;
652 Double_t xpos = track->GetX();
653 Double_t dir = (xpos<xToGo) ? 1. : -1.;
654 Double_t maxStep = 5;
655 Double_t maxSnp = 0.8;
657 while ( (xToGo-xpos)*dir > kEpsilon){
658 Double_t step = dir*TMath::Min(TMath::Abs(xToGo-xpos), maxStep);
659 Double_t x = xpos+step;
660 Double_t xyz0[3],xyz1[3];
661 track->GetXYZ(xyz0); //starting global position
663 if(!track->GetXYZAt(x,GetFieldkG(),xyz1)) return kFALSE; // no prolongation
664 xyz1[2]+=kEpsilon; // waiting for bug correction in geo
666 if(TMath::Abs(track->GetSnpAt(x,GetFieldkG())) >= maxSnp) return kFALSE;
667 if(!track->PropagateTo(x,GetFieldkG())) return kFALSE;
669 if(TMath::Abs(track->GetSnp()) >= maxSnp) return kFALSE;
670 track->GetXYZ(xyz0); // global position
671 Double_t alphan = TMath::ATan2(xyz0[1], xyz0[0]);
673 Double_t ca=TMath::Cos(alphan-track->GetAlpha()),
674 sa=TMath::Sin(alphan-track->GetAlpha());
675 Double_t sf=track->GetSnp(), cf=TMath::Sqrt(1.- sf*sf);
676 Double_t sinNew = sf*ca - cf*sa;
677 if(TMath::Abs(sinNew) >= maxSnp) return kFALSE;
678 if(!track->Rotate(alphan)) return kFALSE;
680 xpos = track->GetX();
684 //---------------------------------------------------------------------------
685 AliESDVertex* AliVertexerTracks::RemoveTracksFromVertex(AliESDVertex *inVtx,
691 // Removes tracks in trksTree from fit of inVtx
694 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraint")) {
695 printf("ERROR: primary vertex has no constraint: cannot remove tracks");
698 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraintOnlyFitter"))
699 printf("WARNING: result of tracks' removal will be only approximately correct");
702 rv(0,0) = inVtx->GetXv();
703 rv(1,0) = inVtx->GetYv();
704 rv(2,0) = inVtx->GetZv();
707 inVtx->GetCovMatrix(cov);
709 vV(0,1) = cov[1]; vV(1,0) = cov[1];
711 vV(0,2) = cov[3]; vV(2,0) = cov[3];
712 vV(1,2) = cov[4]; vV(2,1) = cov[4];
715 TMatrixD sumWi(TMatrixD::kInverted,vV);
716 TMatrixD sumWiri(sumWi,TMatrixD::kMult,rv);
718 Int_t nUsedTrks = inVtx->GetNIndices();
719 Double_t chi2 = inVtx->GetChi2();
721 AliExternalTrackParam *track = 0;
722 Int_t ntrks = (Int_t)trkArray->GetEntriesFast();
723 for(Int_t i=0;i<ntrks;i++) {
724 track = (AliExternalTrackParam*)trkArray->At(i);
725 if(!inVtx->UsesTrack(id[i])) {
726 printf("track %d was not used in vertex fit",id[i]);
729 Double_t alpha = track->GetAlpha();
730 Double_t xl = diamondxy[0]*TMath::Cos(alpha)+diamondxy[1]*TMath::Sin(alpha);
731 track->PropagateTo(xl,GetFieldkG());
732 // vector of track global coordinates
734 // covariance matrix of ri
737 // get space point from track
738 if(!TrackToPoint(track,ri,wWi)) continue;
740 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
746 TMatrixD deltar = rv; deltar -= ri;
747 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
748 Double_t chi2i = deltar(0,0)*wWideltar(0,0)+
749 deltar(1,0)*wWideltar(1,0)+
750 deltar(2,0)*wWideltar(2,0);
751 // remove from total chi2
756 printf("Trying to remove too many tracks!");
764 // new inverted of weights matrix
765 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
767 // new position of primary vertex
768 rvnew.Mult(vVnew,sumWiri);
770 Double_t position[3];
771 position[0] = rvnew(0,0);
772 position[1] = rvnew(1,0);
773 position[2] = rvnew(2,0);
781 // store data in the vertex object
782 AliESDVertex *outVtx = new AliESDVertex(position,cov,chi2,nUsedTrks);
783 outVtx->SetTitle(inVtx->GetTitle());
784 UShort_t *inindices = inVtx->GetIndices();
785 Int_t nIndices = nUsedTrks;
786 UShort_t *outindices = new UShort_t[nIndices];
788 for(Int_t k=0; k<inVtx->GetNIndices(); k++) {
789 Bool_t copyindex=kTRUE;
790 for(Int_t l=0; l<ntrks; l++) {
791 if(inindices[k]==id[l]) copyindex=kFALSE;
794 outindices[j] = inindices[k]; j++;
797 outVtx->SetIndices(nIndices,outindices);
798 delete [] outindices;
801 printf("Vertex before removing tracks:");
802 inVtx->PrintStatus();
803 inVtx->PrintIndices();
804 printf("Vertex after removing tracks:");
805 outVtx->PrintStatus();
806 outVtx->PrintIndices();
811 //---------------------------------------------------------------------------
812 void AliVertexerTracks::SetCuts(Double_t *cuts)
818 SetDCAcutIter0(cuts[1]);
820 if(fMode==0 && cuts[3]<0) SetITSrefitNotRequired();
821 SetMinClusters((Int_t)(TMath::Abs(cuts[3])));
822 SetMinTracks((Int_t)(cuts[4]));
823 SetNSigmad0(cuts[5]);
824 SetMinDetFitter(cuts[6]);
826 SetFiducialRZ(cuts[8],cuts[9]);
830 //---------------------------------------------------------------------------
831 void AliVertexerTracks::SetITSMode(Double_t dcacut,
832 Double_t dcacutIter0,
837 Double_t mindetfitter,
843 // Cut values for ITS mode
847 SetITSrefitRequired();
849 SetITSrefitNotRequired();
852 SetDCAcutIter0(dcacutIter0);
854 SetMinClusters(TMath::Abs(minCls));
855 SetMinTracks(mintrks);
857 SetMinDetFitter(mindetfitter);
859 SetFiducialRZ(fidR,fidZ);
863 //---------------------------------------------------------------------------
864 void AliVertexerTracks::SetTPCMode(Double_t dcacut,
865 Double_t dcacutIter0,
870 Double_t mindetfitter,
876 // Cut values for TPC mode
879 SetITSrefitNotRequired();
881 SetDCAcutIter0(dcacutIter0);
883 SetMinClusters(minCls);
884 SetMinTracks(mintrks);
886 SetMinDetFitter(mindetfitter);
888 SetFiducialRZ(fidR,fidZ);
892 //---------------------------------------------------------------------------
893 void AliVertexerTracks::SetSkipTracks(Int_t n,Int_t *skipped)
896 // Mark the tracks not to be used in the vertex reconstruction.
897 // Tracks are identified by AliESDtrack::GetID()
899 fNTrksToSkip = n; fTrksToSkip = new Int_t[n];
900 for(Int_t i=0;i<n;i++) fTrksToSkip[i] = skipped[i];
903 //---------------------------------------------------------------------------
904 void AliVertexerTracks::SetVtxStart(AliESDVertex *vtx)
907 // Set initial vertex knowledge
909 vtx->GetXYZ(fNominalPos);
910 vtx->GetCovMatrix(fNominalCov);
914 //---------------------------------------------------------------------------
915 void AliVertexerTracks::StrLinVertexFinderMinDist(Int_t optUseWeights)
917 AliExternalTrackParam *track1;
918 const Int_t knacc = (Int_t)fTrkArraySel.GetEntriesFast();
919 static TClonesArray linarray("AliStrLine",knacc);
920 for(Int_t i=0; i<knacc; i++){
921 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
922 Double_t alpha=track1->GetAlpha();
923 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
924 Double_t pos[3],dir[3],sigmasq[3];
925 track1->GetXYZAt(mindist,GetFieldkG(),pos);
926 track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
927 sigmasq[0]=TMath::Sin(alpha)*TMath::Sin(alpha)*track1->GetSigmaY2();
928 sigmasq[1]=TMath::Cos(alpha)*TMath::Cos(alpha)*track1->GetSigmaY2();
929 sigmasq[2]=track1->GetSigmaZ2();
932 if(!TrackToPoint(track1,ri,wWi)) optUseWeights=kFALSE;
935 for(Int_t ia=0;ia<3;ia++){
936 for(Int_t ib=0;ib<3;ib++){
937 wmat[iel]=wWi(ia,ib);
941 new(linarray[i]) AliStrLine(pos,sigmasq,wmat,dir);
943 fVert=TrackletVertexFinder(&linarray,optUseWeights);
946 //---------------------------------------------------------------------------
947 AliESDVertex AliVertexerTracks::TrackletVertexFinder(TClonesArray *lines, Int_t optUseWeights)
949 // Calculate the point at minimum distance to prepared tracks
951 const Int_t knacc = (Int_t)lines->GetEntriesFast();
952 Double_t initPos[3]={0.,0.,0.};
954 Double_t (*vectP0)[3]=new Double_t [knacc][3];
955 Double_t (*vectP1)[3]=new Double_t [knacc][3];
958 Double_t dsum[3]={0,0,0};
960 for(Int_t i=0;i<3;i++){
961 for(Int_t j=0;j<3;j++){
967 for(Int_t i=0; i<knacc; i++){
968 AliStrLine* line1 = (AliStrLine*)lines->At(i);
969 Double_t p0[3],cd[3],sigmasq[3];
973 line1->GetSigma2P0(sigmasq);
974 line1->GetWMatrix(wmat);
977 for(Int_t ia=0;ia<3;ia++){
978 for(Int_t ib=0;ib<3;ib++){
979 wWi(ia,ib)=wmat[iel];
986 Double_t p1[3]={p0[0]+cd[0],p0[1]+cd[1],p0[2]+cd[2]};
996 if(optUseWeights==0)GetStrLinDerivMatrix(p0,p1,matr,dknow);
997 else GetStrLinDerivMatrix(p0,p1,sigmasq,matr,dknow);
1000 for(Int_t iii=0;iii<3;iii++){
1001 dsum[iii]+=dknow[iii];
1002 for(Int_t lj=0;lj<3;lj++) sum[iii][lj]+=matr[iii][lj];
1006 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
1007 Double_t covmatrix[6];
1008 covmatrix[0] = invsumWi(0,0);
1009 covmatrix[1] = invsumWi(0,1);
1010 covmatrix[2] = invsumWi(1,1);
1011 covmatrix[3] = invsumWi(0,2);
1012 covmatrix[4] = invsumWi(1,2);
1013 covmatrix[5] = invsumWi(2,2);
1015 Double_t vett[3][3];
1016 Double_t det=GetDeterminant3X3(sum);
1020 for(Int_t zz=0;zz<3;zz++){
1021 for(Int_t ww=0;ww<3;ww++){
1022 for(Int_t kk=0;kk<3;kk++) vett[ww][kk]=sum[ww][kk];
1024 for(Int_t kk=0;kk<3;kk++) vett[kk][zz]=dsum[kk];
1025 initPos[zz]=GetDeterminant3X3(vett)/det;
1029 for(Int_t i=0; i<knacc; i++){
1030 Double_t p0[3]={0,0,0},p1[3]={0,0,0};
1031 for(Int_t ii=0;ii<3;ii++){
1032 p0[ii]=vectP0[i][ii];
1033 p1[ii]=vectP1[i][ii];
1035 sigma+=GetStrLinMinDist(p0,p1,initPos);
1038 if(sigma>0.) {sigma=TMath::Sqrt(sigma);}else{sigma=999;}
1042 AliESDVertex theVert(initPos,covmatrix,99999.,knacc);
1043 theVert.SetDispersion(sigma);
1048 //---------------------------------------------------------------------------
1049 Bool_t AliVertexerTracks::TrackToPoint(AliExternalTrackParam *t,
1050 TMatrixD &ri,TMatrixD &wWi,
1051 Bool_t uUi3by3) const
1054 // Extract from the AliExternalTrackParam the global coordinates ri and covariance matrix
1055 // wWi of the space point that it represents (to be used in VertexFitter())
1059 Double_t rotAngle = t->GetAlpha();
1060 if(rotAngle<0.) rotAngle += 2.*TMath::Pi();
1061 Double_t cosRot = TMath::Cos(rotAngle);
1062 Double_t sinRot = TMath::Sin(rotAngle);
1064 ri(0,0) = t->GetX()*cosRot-t->GetY()*sinRot;
1065 ri(1,0) = t->GetX()*sinRot+t->GetY()*cosRot;
1066 ri(2,0) = t->GetZ();
1071 // matrix to go from global (x,y,z) to local (y,z);
1080 // covariance matrix of local (y,z) - inverted
1082 uUi(0,0) = t->GetSigmaY2();
1083 uUi(0,1) = t->GetSigmaZY();
1084 uUi(1,0) = t->GetSigmaZY();
1085 uUi(1,1) = t->GetSigmaZ2();
1087 //printf(" %f %f",uUi(0,0),uUi(0,1));
1088 //printf(" %f %f",uUi(1,0),uUi(1,1));
1090 if(uUi.Determinant() <= 0.) return kFALSE;
1091 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
1093 // weights matrix: wWi = qQiT * uUiInv * qQi
1094 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
1095 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
1098 if(fVert.GetNContributors()<1) AliFatal("Vertex from finder is empty");
1099 // matrix to go from global (x,y,z) to local (x,y,z);
1111 // covariance of fVert along the track
1112 Double_t p[3],pt,ptot;
1114 pt = TMath::Sqrt(p[0]*p[0]+p[1]*p[1]);
1115 ptot = TMath::Sqrt(pt*pt+p[2]*p[2]);
1116 Double_t cphi = p[0]/pt; //cos(phi)=px/pt
1117 Double_t sphi = p[1]/pt; //sin(phi)=py/pt
1118 Double_t clambda = pt/ptot; //cos(lambda)=pt/ptot
1119 Double_t slambda = p[2]/ptot; //sin(lambda)=pz/ptot
1120 Double_t covfVert[6];
1121 fVert.GetCovMatrix(covfVert);
1122 Double_t covfVertalongt =
1123 covfVert[0]*cphi*cphi*clambda*clambda
1124 +covfVert[1]*2.*cphi*sphi*clambda*clambda
1125 +covfVert[3]*2.*cphi*clambda*slambda
1126 +covfVert[2]*sphi*sphi*clambda*clambda
1127 +covfVert[4]*2.*sphi*clambda*slambda
1128 +covfVert[5]*slambda*slambda;
1129 // covariance matrix of local (x,y,z) - inverted
1131 uUi(0,0) = covfVertalongt * fnSigmaForUi00 * fnSigmaForUi00;
1132 AliDebug(1,Form("=====> sqrtUi00 cm %f",TMath::Sqrt(uUi(0,0))));
1136 uUi(1,1) = t->GetSigmaY2();
1137 uUi(1,2) = t->GetSigmaZY();
1139 uUi(2,1) = t->GetSigmaZY();
1140 uUi(2,2) = t->GetSigmaZ2();
1141 //printf(" Ui :\n");
1142 //printf(" %f %f\n",uUi(0,0),uUi(0,1));
1143 //printf(" %f %f\n",uUi(1,0),uUi(1,1));
1145 if(uUi.Determinant() <= 0.) return kFALSE;
1146 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
1148 // weights matrix: wWi = qQiT * uUiInv * qQi
1149 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
1150 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
1157 //---------------------------------------------------------------------------
1158 void AliVertexerTracks::TooFewTracks()
1161 // When the number of tracks is < fMinTracks,
1162 // deal with vertices not found and prepare to exit
1164 AliDebug(1,"TooFewTracks");
1166 Double_t pos[3],err[3];
1167 pos[0] = fNominalPos[0];
1168 err[0] = TMath::Sqrt(fNominalCov[0]);
1169 pos[1] = fNominalPos[1];
1170 err[1] = TMath::Sqrt(fNominalCov[2]);
1171 pos[2] = fNominalPos[2];
1172 err[2] = TMath::Sqrt(fNominalCov[5]);
1173 Int_t ncontr = (err[0]>1. ? -1 : -3);
1174 if(fCurrentVertex) { delete fCurrentVertex; fCurrentVertex=0; }
1175 fCurrentVertex = new AliESDVertex(pos,err);
1176 fCurrentVertex->SetNContributors(ncontr);
1179 fCurrentVertex->SetTitle("VertexerTracksWithConstraint");
1181 fCurrentVertex->SetTitle("VertexerTracksNoConstraint");
1184 if(!fTrkArraySel.IsEmpty()) fTrkArraySel.Delete();
1185 if(fIdSel) {delete [] fIdSel; fIdSel=NULL;}
1186 if(fTrksToSkip) {delete [] fTrksToSkip; fTrksToSkip=NULL;}
1190 //---------------------------------------------------------------------------
1191 void AliVertexerTracks::VertexFinder(Int_t optUseWeights)
1194 // Get estimate of vertex position in (x,y) from tracks DCA
1196 Double_t initPos[3];
1198 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
1199 Int_t nacc = (Int_t)fTrkArraySel.GetEntriesFast();
1200 Double_t aver[3]={0.,0.,0.};
1201 Double_t aversq[3]={0.,0.,0.};
1202 Double_t sigmasq[3]={0.,0.,0.};
1205 AliExternalTrackParam *track1;
1206 AliExternalTrackParam *track2;
1207 Double_t pos[3],dir[3];
1208 Double_t alpha,mindist;
1210 for(Int_t i=0; i<nacc; i++){
1211 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
1212 alpha=track1->GetAlpha();
1213 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1214 track1->GetXYZAt(mindist,GetFieldkG(),pos);
1215 track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
1216 AliStrLine *line1 = new AliStrLine(pos,dir);
1218 // AliStrLine *line1 = new AliStrLine();
1219 // track1->ApproximateHelixWithLine(mindist,GetFieldkG(),line1);
1221 for(Int_t j=i+1; j<nacc; j++){
1222 track2 = (AliExternalTrackParam*)fTrkArraySel.At(j);
1223 alpha=track2->GetAlpha();
1224 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1225 track2->GetXYZAt(mindist,GetFieldkG(),pos);
1226 track2->GetPxPyPzAt(mindist,GetFieldkG(),dir);
1227 AliStrLine *line2 = new AliStrLine(pos,dir);
1228 // AliStrLine *line2 = new AliStrLine();
1229 // track2->ApproximateHelixWithLine(mindist,GetFieldkG(),line2);
1230 Double_t distCA=line2->GetDCA(line1);
1231 //printf("%d %d %f\n",i,j,distCA);
1232 if(fDCAcut<=0 || (fDCAcut>0&&distCA<fDCAcut)){
1233 Double_t pnt1[3],pnt2[3],crosspoint[3];
1235 if(optUseWeights<=0){
1236 Int_t retcode = line2->Cross(line1,crosspoint);
1239 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
1240 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1243 if(optUseWeights>0){
1244 Int_t retcode = line1->CrossPoints(line2,pnt1,pnt2);
1247 alpha=track1->GetAlpha();
1248 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
1249 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
1250 alpha=track2->GetAlpha();
1251 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
1252 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
1253 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
1254 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
1255 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
1256 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
1257 crosspoint[0]=wx1*pnt1[0] + wx2*pnt2[0];
1258 crosspoint[1]=wy1*pnt1[1] + wy2*pnt2[1];
1259 crosspoint[2]=wz1*pnt1[2] + wz2*pnt2[2];
1262 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
1263 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1272 for(Int_t jj=0;jj<3;jj++){
1273 initPos[jj] = aver[jj]/ncombi;
1274 //printf("%f\n",initPos[jj]);
1276 sigmasq[jj]=aversq[jj]-initPos[jj]*initPos[jj];
1279 sigma=TMath::Sqrt(TMath::Abs(sigma));
1282 Warning("VertexFinder","Finder did not succed");
1285 fVert.SetXYZ(initPos);
1286 fVert.SetDispersion(sigma);
1287 fVert.SetNContributors(ncombi);
1289 //---------------------------------------------------------------------------
1290 void AliVertexerTracks::VertexFitter()
1293 // The optimal estimate of the vertex position is given by a "weighted
1294 // average of tracks positions".
1295 // Original method: V. Karimaki, CMS Note 97/0051
1297 Bool_t useConstraint = fConstraint;
1298 Double_t initPos[3];
1300 fVert.GetXYZ(initPos);
1302 initPos[0]=fNominalPos[0];
1303 initPos[1]=fNominalPos[1];
1304 initPos[2]=fNominalPos[2];
1307 Int_t nTrksSel = (Int_t)fTrkArraySel.GetEntries();
1308 if(nTrksSel==1) useConstraint=kTRUE;
1309 AliDebug(1,"--- VertexFitter(): start");
1310 AliDebug(1,Form(" Number of tracks in array: %d\n",nTrksSel));
1311 AliDebug(1,Form(" Minimum # tracks required in fit: %d\n",fMinTracks));
1312 AliDebug(1,Form(" Vertex position after finder: %f,%f,%f\n",initPos[0],initPos[1],initPos[2]));
1313 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])));
1315 // special treatment for few-tracks fits (e.g. secondary vertices)
1316 Bool_t uUi3by3 = kFALSE; if(nTrksSel<5 && !useConstraint) uUi3by3 = kTRUE;
1321 rv(0,0) = initPos[0];
1322 rv(1,0) = initPos[1];
1324 Double_t xlStart,alpha;
1326 Double_t chi2,chi2i,chi2b;
1327 AliExternalTrackParam *t = 0;
1330 // initial vertex covariance matrix
1332 vVb(0,0) = fNominalCov[0];
1333 vVb(0,1) = fNominalCov[1];
1335 vVb(1,0) = fNominalCov[1];
1336 vVb(1,1) = fNominalCov[2];
1340 vVb(2,2) = fNominalCov[5];
1341 TMatrixD vVbInv(TMatrixD::kInverted,vVb);
1343 rb(0,0) = fNominalPos[0];
1344 rb(1,0) = fNominalPos[1];
1345 rb(2,0) = fNominalPos[2];
1346 TMatrixD vVbInvrb(vVbInv,TMatrixD::kMult,rb);
1350 // 1st - estimate of vtx using all tracks
1351 // 2nd - estimate of global chi2
1352 for(step=0; step<2; step++) {
1353 AliDebug(1,Form(" step = %d\n",step));
1357 if(step==1) { initPos[0]=rv(0,0); initPos[0]=rv(1,0); }
1359 TMatrixD sumWiri(3,1);
1360 TMatrixD sumWi(3,3);
1361 for(i=0; i<3; i++) {
1363 for(j=0; j<3; j++) sumWi(j,i) = 0.;
1366 // mean vertex constraint
1369 sumWiri(i,0) += vVbInvrb(i,0);
1370 for(k=0;k<3;k++) sumWi(i,k) += vVbInv(i,k);
1373 TMatrixD deltar = rv; deltar -= rb;
1374 TMatrixD vVbInvdeltar(vVbInv,TMatrixD::kMult,deltar);
1375 chi2b = deltar(0,0)*vVbInvdeltar(0,0)+
1376 deltar(1,0)*vVbInvdeltar(1,0)+
1377 deltar(2,0)*vVbInvdeltar(2,0);
1382 for(k=0; k<nTrksSel; k++) {
1383 // get track from track array
1384 t = (AliExternalTrackParam*)fTrkArraySel.At(k);
1385 alpha = t->GetAlpha();
1386 xlStart = initPos[0]*TMath::Cos(alpha)+initPos[1]*TMath::Sin(alpha);
1387 // to vtxSeed (from finder)
1388 t->PropagateTo(xlStart,GetFieldkG());
1390 // vector of track global coordinates
1392 // covariance matrix of ri
1395 // get space point from track
1396 if(!TrackToPoint(t,ri,wWi,uUi3by3)) continue;
1397 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
1400 TMatrixD deltar = rv; deltar -= ri;
1401 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
1402 chi2i = deltar(0,0)*wWideltar(0,0)+
1403 deltar(1,0)*wWideltar(1,0)+
1404 deltar(2,0)*wWideltar(2,0);
1406 // add to total chi2
1413 } // end loop on tracks
1415 if(nTrksUsed < fMinTracks) {
1420 Double_t determinant = sumWi.Determinant();
1421 if(determinant < fMinDetFitter) {
1422 AliDebug(1,Form("det(V) = %f (<%f)\n",determinant,fMinDetFitter));
1428 // inverted of weights matrix
1429 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
1431 // position of primary vertex
1432 rv.Mult(vV,sumWiri);
1434 } // end loop on the 2 steps
1441 Double_t position[3];
1442 position[0] = rv(0,0);
1443 position[1] = rv(1,0);
1444 position[2] = rv(2,0);
1445 Double_t covmatrix[6];
1446 covmatrix[0] = vV(0,0);
1447 covmatrix[1] = vV(0,1);
1448 covmatrix[2] = vV(1,1);
1449 covmatrix[3] = vV(0,2);
1450 covmatrix[4] = vV(1,2);
1451 covmatrix[5] = vV(2,2);
1453 // for correct chi2/ndf, count constraint as additional "track"
1454 if(fConstraint) nTrksUsed++;
1455 // store data in the vertex object
1456 if(fCurrentVertex) { delete fCurrentVertex; fCurrentVertex=0; }
1457 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nTrksUsed);
1459 AliDebug(1," Vertex after fit:");
1460 AliDebug(1,Form("xyz: %f %f %f; nc %d",fCurrentVertex->GetXv(),fCurrentVertex->GetYv(),fCurrentVertex->GetZv(),fCurrentVertex->GetNContributors()));
1461 AliDebug(1,"--- VertexFitter(): finish\n");
1466 //----------------------------------------------------------------------------
1467 AliESDVertex* AliVertexerTracks::VertexForSelectedTracks(TObjArray *trkArray,
1469 Bool_t optUseFitter,
1470 Bool_t optPropagate)
1473 // Return vertex from tracks (AliExternalTrackParam) in array
1478 // get tracks and propagate them to initial vertex position
1479 fIdSel = new UShort_t[(Int_t)trkArray->GetEntriesFast()];
1480 Int_t nTrksSel = PrepareTracks(*trkArray,id,0);
1481 if(nTrksSel < TMath::Max(2,fMinTracks)) {
1483 return fCurrentVertex;
1488 case 1: StrLinVertexFinderMinDist(1); break;
1489 case 2: StrLinVertexFinderMinDist(0); break;
1490 case 3: HelixVertexFinder(); break;
1491 case 4: VertexFinder(1); break;
1492 case 5: VertexFinder(0); break;
1493 default: printf("Wrong algorithm\n"); break;
1495 AliDebug(1," Vertex finding completed\n");
1501 Double_t position[3]={fVert.GetXv(),fVert.GetYv(),fVert.GetZv()};
1502 Double_t covmatrix[6];
1503 fVert.GetCovMatrix(covmatrix);
1504 Double_t chi2=99999.;
1505 Int_t nTrksUsed=fVert.GetNContributors();
1506 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nTrksUsed);
1508 fCurrentVertex->SetDispersion(fVert.GetDispersion());
1511 // set indices of used tracks and propagate track to found vertex
1512 UShort_t *indices = 0;
1513 Double_t d0z0[2],covd0z0[3];
1514 AliExternalTrackParam *t = 0;
1515 if(fCurrentVertex->GetNContributors()>0) {
1516 indices = new UShort_t[fCurrentVertex->GetNContributors()];
1517 for(Int_t jj=0; jj<(Int_t)fTrkArraySel.GetEntriesFast(); jj++) {
1518 indices[jj] = fIdSel[jj];
1519 t = (AliExternalTrackParam*)fTrkArraySel.At(jj);
1520 if(optPropagate && optUseFitter) {
1521 if(TMath::Sqrt(fCurrentVertex->GetXv()*fCurrentVertex->GetXv()+fCurrentVertex->GetYv()*fCurrentVertex->GetYv())<3.) {
1522 t->PropagateToDCA(fCurrentVertex,GetFieldkG(),100.,d0z0,covd0z0);
1523 AliDebug(1,Form("Track %d propagated to found vertex",jj));
1525 AliWarning("Found vertex outside beam pipe!");
1529 fCurrentVertex->SetIndices(fCurrentVertex->GetNContributors(),indices);
1533 delete [] indices; indices=NULL;
1534 delete [] fIdSel; fIdSel=NULL;
1535 fTrkArraySel.Delete();
1537 return fCurrentVertex;
1539 //----------------------------------------------------------------------------
1540 AliESDVertex* AliVertexerTracks::VertexForSelectedESDTracks(TObjArray *trkArray,
1541 Bool_t optUseFitter,
1542 Bool_t optPropagate)
1545 // Return vertex from array of ESD tracks
1548 Int_t nTrks = (Int_t)trkArray->GetEntriesFast();
1549 UShort_t *id = new UShort_t[nTrks];
1551 AliESDtrack *esdt = 0;
1552 for(Int_t i=0; i<nTrks; i++){
1553 esdt = (AliESDtrack*)trkArray->At(i);
1554 id[i] = (UShort_t)esdt->GetID();
1557 VertexForSelectedTracks(trkArray,id,optUseFitter,optPropagate);
1559 delete [] id; id=NULL;
1561 return fCurrentVertex;
1563 //--------------------------------------------------------------------------