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 "AliNeutralTrackParam.h"
39 #include "AliVEvent.h"
40 #include "AliVTrack.h"
41 #include "AliESDEvent.h"
42 #include "AliESDtrack.h"
43 #include "AliVertexerTracks.h"
45 ClassImp(AliVertexerTracks)
48 //----------------------------------------------------------------------------
49 AliVertexerTracks::AliVertexerTracks():
77 // Default constructor
82 //----------------------------------------------------------------------------
83 AliVertexerTracks::AliVertexerTracks(Double_t fieldkG):
111 // Standard constructor
116 //-----------------------------------------------------------------------------
117 AliVertexerTracks::~AliVertexerTracks()
119 // Default Destructor
120 // The objects pointed by the following pointer are not owned
121 // by this class and are not deleted
123 if(fTrksToSkip) { delete [] fTrksToSkip; fTrksToSkip=NULL; }
124 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
126 //----------------------------------------------------------------------------
127 AliESDVertex* AliVertexerTracks::FindPrimaryVertex(const AliVEvent *vEvent)
130 // Primary vertex for current ESD or AOD event
132 // 1st with 5*fNSigma*sigma cut w.r.t. to initial vertex
133 // + cut on sqrt(d0d0+z0z0) if fConstraint=kFALSE
134 // 2nd with fNSigma*sigma cut w.r.t. to vertex found in 1st iteration)
138 TString evtype = vEvent->IsA()->GetName();
139 Bool_t inputAOD = ((evtype=="AliAODEvent") ? kTRUE : kFALSE);
141 if(inputAOD && fMode==1) {
142 printf("Error : AliVertexerTracks: no TPC-only vertex from AOD\n");
144 return fCurrentVertex;
147 // accept 1-track case only if constraint is available
148 if(!fConstraint && fMinTracks==1) fMinTracks=2;
150 // read tracks from AlivEvent
151 Int_t nTrks = (Int_t)vEvent->GetNumberOfTracks();
152 if(nTrks<fMinTracks) {
154 return fCurrentVertex;
158 TDirectory * olddir = gDirectory;
160 if(nTrks>500) f = new TFile("VertexerTracks.root","recreate");
161 TObjArray trkArrayOrig(nTrks);
162 UShort_t *idOrig = new UShort_t[nTrks];
165 AliExternalTrackParam *t=0;
167 for(Int_t i=0; i<nTrks; i++) {
168 AliVTrack *track = (AliVTrack*)vEvent->GetTrack(i);
169 // check tracks to skip
170 Bool_t skipThis = kFALSE;
171 for(Int_t j=0; j<fNTrksToSkip; j++) {
172 if(track->GetID()==fTrksToSkip[j]) {
173 AliDebug(1,Form("skipping track: %d",i));
177 if(skipThis) continue;
180 if(fMode==0 && fITSrefit && !(track->GetStatus()&AliESDtrack::kITSrefit)) continue;
182 if(!inputAOD) { // ESD
183 AliESDtrack* esdt = (AliESDtrack*)track;
184 if(esdt->GetNcls(fMode) < fMinClusters) continue;
185 if(fMode==0) { // ITS mode
186 Double_t x,p[5],cov[15];
187 esdt->GetExternalParameters(x,p);
188 esdt->GetExternalCovariance(cov);
189 t = new AliExternalTrackParam(x,esdt->GetAlpha(),p,cov);
190 } else if(fMode==1) { // TPC mode
191 t = (AliExternalTrackParam*)esdt->GetTPCInnerParam();
193 Double_t radius = 2.8; //something less than the beam pipe radius
194 if(!PropagateTrackTo(t,radius)) continue;
196 } else { // AOD (only ITS mode)
198 for(Int_t l=0;l<6;l++) if(TESTBIT(track->GetITSClusterMap(),l)) ncls0++;
199 if(ncls0 < fMinClusters) continue;
200 t = new AliExternalTrackParam(track);
202 trkArrayOrig.AddLast(t);
203 idOrig[nTrksOrig]=(UShort_t)track->GetID();
205 } // end loop on tracks
207 // call method that will reconstruct the vertex
208 FindPrimaryVertex(&trkArrayOrig,idOrig);
210 if(fMode==0) trkArrayOrig.Delete();
211 delete [] idOrig; idOrig=NULL;
214 f->Close(); delete f; f = NULL;
215 gSystem->Unlink("VertexerTracks.root");
219 return fCurrentVertex;
221 //----------------------------------------------------------------------------
222 AliESDVertex* AliVertexerTracks::FindPrimaryVertex(TObjArray *trkArrayOrig,
226 // Primary vertex using the AliExternalTrackParam's in the TObjArray.
227 // idOrig must contain the track IDs from AliESDtrack::GetID()
229 // 1st with 5*fNSigma*sigma cut w.r.t. to initial vertex
230 // + cut on sqrt(d0d0+z0z0) if fConstraint=kFALSE
231 // 2nd with fNSigma*sigma cut w.r.t. to vertex found in 1st iteration)
235 // accept 1-track case only if constraint is available
236 if(!fConstraint && fMinTracks==1) fMinTracks=2;
238 // read tracks from array
239 Int_t nTrksOrig = (Int_t)trkArrayOrig->GetEntriesFast();
240 AliDebug(1,Form("Initial number of tracks: %d",nTrksOrig));
241 if(nTrksOrig<fMinTracks) {
242 AliDebug(1,"TooFewTracks");
244 return fCurrentVertex;
247 // If fConstraint=kFALSE
248 // run VertexFinder(1) to get rough estimate of initVertex (x,y)
250 // fill fTrkArraySel, for VertexFinder()
251 fIdSel = new UShort_t[nTrksOrig];
252 PrepareTracks(*trkArrayOrig,idOrig,0);
253 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
254 Double_t cutsave = fDCAcut;
255 fDCAcut = fDCAcutIter0;
257 switch (fAlgoIter0) {
258 case 1: StrLinVertexFinderMinDist(1); break;
259 case 2: StrLinVertexFinderMinDist(0); break;
260 case 3: HelixVertexFinder(); break;
261 case 4: VertexFinder(1); break;
262 case 5: VertexFinder(0); break;
263 default: printf("Wrong algorithm\n"); break;
266 if(fVert.GetNContributors()>0) {
267 fVert.GetXYZ(fNominalPos);
268 fNominalPos[0] = fVert.GetXv();
269 fNominalPos[1] = fVert.GetYv();
270 fNominalPos[2] = fVert.GetZv();
271 AliDebug(1,Form("No mean vertex: VertexFinder gives (%f, %f, %f)",fNominalPos[0],fNominalPos[1],fNominalPos[2]));
276 AliDebug(1,"No mean vertex and VertexFinder failed");
283 // propagate tracks to fNominalPos vertex
285 // if(constraint) reject for |d0|>5*fNSigma*sigma w.r.t. fNominal... vertex
286 // else reject for |d0|\oplus|z0| > 5 mm w.r.t. fNominal... vertex
288 // propagate tracks to best between initVertex and fCurrentVertex
289 // preselect tracks (reject for |d0|>fNSigma*sigma w.r.t. best
290 // between initVertex and fCurrentVertex)
291 for(Int_t iter=1; iter<=2; iter++) {
292 if(fOnlyFitter && iter==1) continue;
293 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
294 fIdSel = new UShort_t[nTrksOrig];
295 Int_t nTrksSel = PrepareTracks(*trkArrayOrig,idOrig,iter);
296 AliDebug(1,Form("N tracks selected in iteration %d: %d",iter,nTrksSel));
297 if(nTrksSel < fMinTracks) {
299 return fCurrentVertex;
305 AliDebug(1,"Just one track");
306 OneTrackVertFinder();
309 case 1: StrLinVertexFinderMinDist(1); break;
310 case 2: StrLinVertexFinderMinDist(0); break;
311 case 3: HelixVertexFinder(); break;
312 case 4: VertexFinder(1); break;
313 case 5: VertexFinder(0); break;
314 default: printf("Wrong algorithm"); break;
317 AliDebug(1," Vertex finding completed");
322 } // end loop on the two iterations
325 // set indices of used tracks
326 UShort_t *indices = 0;
327 if(fCurrentVertex->GetNContributors()>0) {
328 Int_t nIndices = (Int_t)fTrkArraySel.GetEntriesFast();
329 indices = new UShort_t[nIndices];
330 for(Int_t jj=0; jj<nIndices; jj++)
331 indices[jj] = fIdSel[jj];
332 fCurrentVertex->SetIndices(nIndices,indices);
334 delete [] indices; indices=NULL;
338 TString title="VertexerTracksNoConstraint";
340 title="VertexerTracksWithConstraint";
341 if(fOnlyFitter) title.Append("OnlyFitter");
343 fCurrentVertex->SetTitle(title.Data());
346 AliDebug(1,Form("xyz: %f %f %f; nc %d",fCurrentVertex->GetXv(),fCurrentVertex->GetYv(),fCurrentVertex->GetZv(),fCurrentVertex->GetNContributors()));
349 delete [] fIdSel; fIdSel=NULL;
350 fTrkArraySel.Delete();
351 if(fTrksToSkip) { delete [] fTrksToSkip; fTrksToSkip=NULL; }
354 return fCurrentVertex;
356 //------------------------------------------------------------------------
357 Double_t AliVertexerTracks::GetDeterminant3X3(Double_t matr[][3])
360 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];
363 //-------------------------------------------------------------------------
364 void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t (*m)[3],Double_t *d)
367 Double_t x12=p0[0]-p1[0];
368 Double_t y12=p0[1]-p1[1];
369 Double_t z12=p0[2]-p1[2];
370 Double_t kk=x12*x12+y12*y12+z12*z12;
371 m[0][0]=2-2/kk*x12*x12;
372 m[0][1]=-2/kk*x12*y12;
373 m[0][2]=-2/kk*x12*z12;
374 m[1][0]=-2/kk*x12*y12;
375 m[1][1]=2-2/kk*y12*y12;
376 m[1][2]=-2/kk*y12*z12;
377 m[2][0]=-2/kk*x12*z12;
379 m[2][2]=2-2/kk*z12*z12;
380 d[0]=2*p0[0]-2/kk*p0[0]*x12*x12-2/kk*p0[2]*x12*z12-2/kk*p0[1]*x12*y12;
381 d[1]=2*p0[1]-2/kk*p0[1]*y12*y12-2/kk*p0[0]*x12*y12-2/kk*p0[2]*z12*y12;
382 d[2]=2*p0[2]-2/kk*p0[2]*z12*z12-2/kk*p0[0]*x12*z12-2/kk*p0[1]*z12*y12;
385 //--------------------------------------------------------------------------
386 void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t *sigmasq,Double_t (*m)[3],Double_t *d)
389 Double_t x12=p1[0]-p0[0];
390 Double_t y12=p1[1]-p0[1];
391 Double_t z12=p1[2]-p0[2];
393 Double_t den= x12*x12*sigmasq[1]*sigmasq[2]+y12*y12*sigmasq[0]*sigmasq[2]+z12*z12*sigmasq[0]*sigmasq[1];
395 Double_t kk= 2*(x12*x12/sigmasq[0]+y12*y12/sigmasq[1]+z12*z12/sigmasq[2]);
398 cc[0]=-x12/sigmasq[0];
399 cc[1]=-y12/sigmasq[1];
400 cc[2]=-z12/sigmasq[2];
402 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;
404 Double_t ss= -p0[0]*cc[0]-p0[1]*cc[1]-p0[2]*cc[2];
407 aa[0]=x12*sigmasq[1]*sigmasq[2]/den;
408 aa[1]=y12*sigmasq[0]*sigmasq[2]/den;
409 aa[2]=z12*sigmasq[0]*sigmasq[1]/den;
411 m[0][0]=aa[0]*(aa[0]*kk+2*cc[0])+2*cc[0]*aa[0]+2/sigmasq[0];
412 m[0][1]=aa[1]*(aa[0]*kk+2*cc[0])+2*cc[1]*aa[0];
413 m[0][2]=aa[2]*(aa[0]*kk+2*cc[0])+2*cc[2]*aa[0];
415 m[1][0]=aa[0]*(aa[1]*kk+2*cc[1])+2*cc[0]*aa[1];
416 m[1][1]=aa[1]*(aa[1]*kk+2*cc[1])+2*cc[1]*aa[1]+2/sigmasq[1];
417 m[1][2]=aa[2]*(aa[1]*kk+2*cc[1])+2*cc[2]*aa[1];
419 m[2][0]=aa[0]*(aa[2]*kk+2*cc[2])+2*cc[0]*aa[2];
420 m[2][1]=aa[1]*(aa[2]*kk+2*cc[2])+2*cc[1]*aa[2];
421 m[2][2]=aa[2]*(aa[2]*kk+2*cc[2])+2*cc[2]*aa[2]+2/sigmasq[2];
423 d[0]=-ww*(aa[0]*kk+2*cc[0])-2*ss*aa[0]+2*p0[0]/sigmasq[0];
424 d[1]=-ww*(aa[1]*kk+2*cc[1])-2*ss*aa[1]+2*p0[1]/sigmasq[1];
425 d[2]=-ww*(aa[2]*kk+2*cc[2])-2*ss*aa[2]+2*p0[2]/sigmasq[2];
428 //--------------------------------------------------------------------------
429 Double_t AliVertexerTracks::GetStrLinMinDist(Double_t *p0,Double_t *p1,Double_t *x0)
432 Double_t x12=p0[0]-p1[0];
433 Double_t y12=p0[1]-p1[1];
434 Double_t z12=p0[2]-p1[2];
435 Double_t x10=p0[0]-x0[0];
436 Double_t y10=p0[1]-x0[1];
437 Double_t z10=p0[2]-x0[2];
438 // 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);
439 return ((y10*z12-z10*y12)*(y10*z12-z10*y12)+
440 (z10*x12-x10*z12)*(z10*x12-x10*z12)+
441 (x10*y12-y10*x12)*(x10*y12-y10*x12))
442 /(x12*x12+y12*y12+z12*z12);
444 //---------------------------------------------------------------------------
445 void AliVertexerTracks::OneTrackVertFinder()
447 // find vertex for events with 1 track, using DCA to nominal beam axis
448 AliDebug(1,Form("Number of prepared tracks =%d - Call OneTrackVertFinder",fTrkArraySel.GetEntries()));
449 AliExternalTrackParam *track1;
450 track1 = (AliExternalTrackParam*)fTrkArraySel.At(0);
451 Double_t alpha=track1->GetAlpha();
452 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
453 Double_t pos[3],dir[3];
454 track1->GetXYZAt(mindist,GetFieldkG(),pos);
455 track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
456 AliStrLine *line1 = new AliStrLine(pos,dir);
457 Double_t p1[3]={fNominalPos[0],fNominalPos[1],0.};
458 Double_t p2[3]={fNominalPos[0],fNominalPos[1],10.};
459 AliStrLine *zeta=new AliStrLine(p1,p2,kTRUE);
460 Double_t crosspoint[3]={0.,0.,0.};
463 Int_t retcode = zeta->Cross(line1,crosspoint);
465 sigma=line1->GetDistFromPoint(crosspoint);
470 fVert.SetXYZ(crosspoint);
471 fVert.SetDispersion(sigma);
472 fVert.SetNContributors(nContrib);
474 //---------------------------------------------------------------------------
475 void AliVertexerTracks::HelixVertexFinder()
477 // Get estimate of vertex position in (x,y) from tracks DCA
482 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
484 Int_t nacc = (Int_t)fTrkArraySel.GetEntriesFast();
486 Double_t aver[3]={0.,0.,0.};
487 Double_t averquad[3]={0.,0.,0.};
488 Double_t sigmaquad[3]={0.,0.,0.};
491 AliExternalTrackParam *track1;
492 AliExternalTrackParam *track2;
495 Double_t alpha, cs, sn;
496 Double_t crosspoint[3];
497 for(Int_t i=0; i<nacc; i++){
498 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
501 for(Int_t j=i+1; j<nacc; j++){
502 track2 = (AliExternalTrackParam*)fTrkArraySel.At(j);
504 distCA=track2->PropagateToDCA(track1,GetFieldkG());
505 if(fDCAcut<=0 ||(fDCAcut>0&&distCA<fDCAcut)){
507 alpha=track1->GetAlpha();
508 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
509 Double_t x1=x*cs - track1->GetY()*sn;
510 Double_t y1=x*sn + track1->GetY()*cs;
511 Double_t z1=track1->GetZ();
513 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
515 alpha=track2->GetAlpha();
516 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
517 Double_t x2=x*cs - track2->GetY()*sn;
518 Double_t y2=x*sn + track2->GetY()*cs;
519 Double_t z2=track2->GetZ();
520 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
521 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
522 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
523 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
524 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
525 crosspoint[0]=wx1*x1 + wx2*x2;
526 crosspoint[1]=wy1*y1 + wy2*y2;
527 crosspoint[2]=wz1*z1 + wz2*z2;
530 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
531 for(Int_t jj=0;jj<3;jj++)averquad[jj]+=(crosspoint[jj]*crosspoint[jj]);
537 for(Int_t jj=0;jj<3;jj++){
538 initPos[jj] = aver[jj]/ncombi;
539 averquad[jj]/=ncombi;
540 sigmaquad[jj]=averquad[jj]-initPos[jj]*initPos[jj];
541 sigma+=sigmaquad[jj];
543 sigma=TMath::Sqrt(TMath::Abs(sigma));
546 Warning("HelixVertexFinder","Finder did not succed");
549 fVert.SetXYZ(initPos);
550 fVert.SetDispersion(sigma);
551 fVert.SetNContributors(ncombi);
553 //----------------------------------------------------------------------------
554 Int_t AliVertexerTracks::PrepareTracks(TObjArray &trkArrayOrig,
559 // Propagate tracks to initial vertex position and store them in a TObjArray
561 AliDebug(1," PrepareTracks()");
563 Int_t nTrksOrig = (Int_t)trkArrayOrig.GetEntriesFast();
566 Double_t sigmaCurr[3];
567 Double_t normdistx,normdisty;
568 Double_t d0z0[2],covd0z0[3];
571 AliESDVertex *initVertex = new AliESDVertex(fNominalPos,fNominalCov,1,1);
573 if(!fTrkArraySel.IsEmpty()) fTrkArraySel.Delete();
575 AliExternalTrackParam *track=0;
578 for(Int_t i=0; i<nTrksOrig; i++) {
579 AliExternalTrackParam *trackOrig=(AliExternalTrackParam*)trkArrayOrig.At(i);
580 if(trackOrig->Charge()!=0) { // normal tracks
581 track = new AliExternalTrackParam(*(AliExternalTrackParam*)trkArrayOrig.At(i));
582 } else { // neutral tracks (from a V0)
583 track = new AliNeutralTrackParam(*(AliNeutralTrackParam*)trkArrayOrig.At(i));
587 if(TMath::Abs(track->GetTgl())>fMaxTgl) {
588 AliDebug(1,Form(" rejecting track with tgl = %f",track->GetTgl()));
589 delete track; continue;
592 Bool_t propagateOK = kFALSE;
593 // propagate track to vertex
594 if(optImpParCut<2 || fOnlyFitter) { // optImpParCut==1 or 0
595 propagateOK = track->PropagateToDCA(initVertex,GetFieldkG(),100.,d0z0,covd0z0);
596 } else { // optImpParCut==2
597 fCurrentVertex->GetSigmaXYZ(sigmaCurr);
598 normdistx = TMath::Abs(fCurrentVertex->GetXv()-fNominalPos[0])/TMath::Sqrt(sigmaCurr[0]*sigmaCurr[0]+fNominalCov[0]);
599 normdisty = TMath::Abs(fCurrentVertex->GetYv()-fNominalPos[1])/TMath::Sqrt(sigmaCurr[1]*sigmaCurr[1]+fNominalCov[2]);
600 if(normdistx < 3. && normdisty < 3. &&
601 (sigmaCurr[0]+sigmaCurr[1])<(TMath::Sqrt(fNominalCov[0])+TMath::Sqrt(fNominalCov[2]))) {
602 propagateOK = track->PropagateToDCA(fCurrentVertex,GetFieldkG(),100.,d0z0,covd0z0);
604 propagateOK = track->PropagateToDCA(initVertex,GetFieldkG(),100.,d0z0,covd0z0);
609 AliDebug(1," rejected");
610 delete track; continue;
613 sigmad0 = TMath::Sqrt(covd0z0[0]);
614 maxd0rphi = fNSigma*sigmad0;
615 if(optImpParCut==1) maxd0rphi *= 5.;
616 maxd0rphi = TMath::Min(maxd0rphi,fFiducialR);
617 //sigmad0z0 = TMath::Sqrt(covd0z0[0]+covd0z0[2]); // for future improvement
618 //maxd0z0 = 10.*fNSigma*sigmad0z0;
620 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));
623 //---- track selection based on impact parameters ----//
625 // always reject tracks outside fiducial volume
626 if(TMath::Abs(d0z0[0])>fFiducialR || TMath::Abs(d0z0[1])>fFiducialZ) {
627 AliDebug(1," rejected");
628 delete track; continue;
631 // during iterations 1 and 2 , reject tracks with d0rphi > maxd0rphi
632 if(optImpParCut>0 && TMath::Abs(d0z0[0])>maxd0rphi) {
633 AliDebug(1," rejected");
634 delete track; continue;
637 // if fConstraint=kFALSE, during iterations 1 and 2 ||
638 // if fConstraint=kTRUE, during iteration 2,
639 // select tracks with d0oplusz0 < fMaxd0z0
640 if((!fConstraint && optImpParCut>0 && fVert.GetNContributors()>0) ||
641 ( fConstraint && optImpParCut==2)) {
643 TMath::Sqrt(d0z0[0]*d0z0[0]+d0z0[1]*d0z0[1])>fMaxd0z0) {
644 AliDebug(1," rejected");
645 delete track; continue;
649 // track passed all selections
650 fTrkArraySel.AddLast(track);
651 fIdSel[nTrksSel] = idOrig[i];
653 } // end loop on tracks
659 //----------------------------------------------------------------------------
660 Bool_t AliVertexerTracks::PropagateTrackTo(AliExternalTrackParam *track,
662 //----------------------------------------------------------------
663 // COPIED from AliTracker
665 // Propagates the track to the plane X=xk (cm).
667 // Origin: Marian Ivanov, Marian.Ivanov@cern.ch
668 //----------------------------------------------------------------
670 const Double_t kEpsilon = 0.00001;
671 Double_t xpos = track->GetX();
672 Double_t dir = (xpos<xToGo) ? 1. : -1.;
673 Double_t maxStep = 5;
674 Double_t maxSnp = 0.8;
676 while ( (xToGo-xpos)*dir > kEpsilon){
677 Double_t step = dir*TMath::Min(TMath::Abs(xToGo-xpos), maxStep);
678 Double_t x = xpos+step;
679 Double_t xyz0[3],xyz1[3];
680 track->GetXYZ(xyz0); //starting global position
682 if(!track->GetXYZAt(x,GetFieldkG(),xyz1)) return kFALSE; // no prolongation
683 xyz1[2]+=kEpsilon; // waiting for bug correction in geo
685 if(TMath::Abs(track->GetSnpAt(x,GetFieldkG())) >= maxSnp) return kFALSE;
686 if(!track->PropagateTo(x,GetFieldkG())) return kFALSE;
688 if(TMath::Abs(track->GetSnp()) >= maxSnp) return kFALSE;
689 track->GetXYZ(xyz0); // global position
690 Double_t alphan = TMath::ATan2(xyz0[1], xyz0[0]);
692 Double_t ca=TMath::Cos(alphan-track->GetAlpha()),
693 sa=TMath::Sin(alphan-track->GetAlpha());
694 Double_t sf=track->GetSnp(), cf=TMath::Sqrt((1.-sf)*(1.+sf));
695 Double_t sinNew = sf*ca - cf*sa;
696 if(TMath::Abs(sinNew) >= maxSnp) return kFALSE;
697 if(!track->Rotate(alphan)) return kFALSE;
699 xpos = track->GetX();
703 //---------------------------------------------------------------------------
704 AliESDVertex* AliVertexerTracks::RemoveTracksFromVertex(AliESDVertex *inVtx,
710 // Removes tracks in trksTree from fit of inVtx
713 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraint")) {
714 printf("ERROR: primary vertex has no constraint: cannot remove tracks");
717 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraintOnlyFitter"))
718 printf("WARNING: result of tracks' removal will be only approximately correct");
721 rv(0,0) = inVtx->GetXv();
722 rv(1,0) = inVtx->GetYv();
723 rv(2,0) = inVtx->GetZv();
726 inVtx->GetCovMatrix(cov);
728 vV(0,1) = cov[1]; vV(1,0) = cov[1];
730 vV(0,2) = cov[3]; vV(2,0) = cov[3];
731 vV(1,2) = cov[4]; vV(2,1) = cov[4];
734 TMatrixD sumWi(TMatrixD::kInverted,vV);
735 TMatrixD sumWiri(sumWi,TMatrixD::kMult,rv);
737 Int_t nUsedTrks = inVtx->GetNIndices();
738 Double_t chi2 = inVtx->GetChi2();
740 AliExternalTrackParam *track = 0;
741 Int_t ntrks = (Int_t)trkArray->GetEntriesFast();
742 for(Int_t i=0;i<ntrks;i++) {
743 track = (AliExternalTrackParam*)trkArray->At(i);
744 if(!inVtx->UsesTrack(id[i])) {
745 printf("track %d was not used in vertex fit",id[i]);
748 Double_t alpha = track->GetAlpha();
749 Double_t xl = diamondxy[0]*TMath::Cos(alpha)+diamondxy[1]*TMath::Sin(alpha);
750 track->PropagateTo(xl,GetFieldkG());
751 // vector of track global coordinates
753 // covariance matrix of ri
756 // get space point from track
757 if(!TrackToPoint(track,ri,wWi)) continue;
759 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
765 TMatrixD deltar = rv; deltar -= ri;
766 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
767 Double_t chi2i = deltar(0,0)*wWideltar(0,0)+
768 deltar(1,0)*wWideltar(1,0)+
769 deltar(2,0)*wWideltar(2,0);
770 // remove from total chi2
775 printf("Trying to remove too many tracks!");
783 // new inverted of weights matrix
784 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
786 // new position of primary vertex
787 rvnew.Mult(vVnew,sumWiri);
789 Double_t position[3];
790 position[0] = rvnew(0,0);
791 position[1] = rvnew(1,0);
792 position[2] = rvnew(2,0);
800 // store data in the vertex object
801 AliESDVertex *outVtx = new AliESDVertex(position,cov,chi2,nUsedTrks);
802 outVtx->SetTitle(inVtx->GetTitle());
803 UShort_t *inindices = inVtx->GetIndices();
804 Int_t nIndices = nUsedTrks;
805 UShort_t *outindices = new UShort_t[nIndices];
807 for(Int_t k=0; k<inVtx->GetNIndices(); k++) {
808 Bool_t copyindex=kTRUE;
809 for(Int_t l=0; l<ntrks; l++) {
810 if(inindices[k]==id[l]) copyindex=kFALSE;
813 outindices[j] = inindices[k]; j++;
816 outVtx->SetIndices(nIndices,outindices);
817 delete [] outindices;
820 printf("Vertex before removing tracks:");
821 inVtx->PrintStatus();
822 inVtx->PrintIndices();
823 printf("Vertex after removing tracks:");
824 outVtx->PrintStatus();
825 outVtx->PrintIndices();
830 //---------------------------------------------------------------------------
831 void AliVertexerTracks::SetCuts(Double_t *cuts)
837 SetDCAcutIter0(cuts[1]);
839 if(fMode==0 && cuts[3]<0) SetITSrefitNotRequired();
840 SetMinClusters((Int_t)(TMath::Abs(cuts[3])));
841 SetMinTracks((Int_t)(cuts[4]));
842 SetNSigmad0(cuts[5]);
843 SetMinDetFitter(cuts[6]);
845 SetFiducialRZ(cuts[8],cuts[9]);
846 fAlgo=(Int_t)(cuts[10]);
847 fAlgoIter0=(Int_t)(cuts[11]);
851 //---------------------------------------------------------------------------
852 void AliVertexerTracks::SetITSMode(Double_t dcacut,
853 Double_t dcacutIter0,
858 Double_t mindetfitter,
863 Int_t finderAlgoIter0)
866 // Cut values for ITS mode
870 SetITSrefitRequired();
872 SetITSrefitNotRequired();
875 SetDCAcutIter0(dcacutIter0);
877 SetMinClusters(TMath::Abs(minCls));
878 SetMinTracks(mintrks);
880 SetMinDetFitter(mindetfitter);
882 SetFiducialRZ(fidR,fidZ);
884 fAlgoIter0=finderAlgoIter0;
888 //---------------------------------------------------------------------------
889 void AliVertexerTracks::SetTPCMode(Double_t dcacut,
890 Double_t dcacutIter0,
895 Double_t mindetfitter,
900 Int_t finderAlgoIter0)
903 // Cut values for TPC mode
906 SetITSrefitNotRequired();
908 SetDCAcutIter0(dcacutIter0);
910 SetMinClusters(minCls);
911 SetMinTracks(mintrks);
913 SetMinDetFitter(mindetfitter);
915 SetFiducialRZ(fidR,fidZ);
917 fAlgoIter0=finderAlgoIter0;
921 //---------------------------------------------------------------------------
922 void AliVertexerTracks::SetSkipTracks(Int_t n,Int_t *skipped)
925 // Mark the tracks not to be used in the vertex reconstruction.
926 // Tracks are identified by AliESDtrack::GetID()
928 fNTrksToSkip = n; fTrksToSkip = new Int_t[n];
929 for(Int_t i=0;i<n;i++) fTrksToSkip[i] = skipped[i];
932 //---------------------------------------------------------------------------
933 void AliVertexerTracks::SetVtxStart(AliESDVertex *vtx)
936 // Set initial vertex knowledge
938 vtx->GetXYZ(fNominalPos);
939 vtx->GetCovMatrix(fNominalCov);
943 //---------------------------------------------------------------------------
944 void AliVertexerTracks::StrLinVertexFinderMinDist(Int_t optUseWeights)
946 AliExternalTrackParam *track1;
947 const Int_t knacc = (Int_t)fTrkArraySel.GetEntriesFast();
948 AliStrLine **linarray = new AliStrLine* [knacc];
949 for(Int_t i=0; i<knacc; i++){
950 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
951 Double_t alpha=track1->GetAlpha();
952 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
953 Double_t pos[3],dir[3],sigmasq[3];
954 track1->GetXYZAt(mindist,GetFieldkG(),pos);
955 track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
956 sigmasq[0]=TMath::Sin(alpha)*TMath::Sin(alpha)*track1->GetSigmaY2();
957 sigmasq[1]=TMath::Cos(alpha)*TMath::Cos(alpha)*track1->GetSigmaY2();
958 sigmasq[2]=track1->GetSigmaZ2();
961 if(!TrackToPoint(track1,ri,wWi)) {optUseWeights=kFALSE;printf("WARNING\n");}
964 for(Int_t ia=0;ia<3;ia++){
965 for(Int_t ib=0;ib<3;ib++){
966 wmat[iel]=wWi(ia,ib);
970 linarray[i] = new AliStrLine(pos,sigmasq,wmat,dir);
972 fVert=TrackletVertexFinder(linarray,knacc,optUseWeights);
973 for(Int_t i=0; i<knacc; i++) delete linarray[i];
976 //---------------------------------------------------------------------------
977 AliESDVertex AliVertexerTracks::TrackletVertexFinder(TClonesArray *lines, Int_t optUseWeights)
979 // Calculate the point at minimum distance to prepared tracks (TClonesArray)
980 const Int_t knacc = (Int_t)lines->GetEntriesFast();
981 AliStrLine** lines2 = new AliStrLine* [knacc];
982 for(Int_t i=0; i<knacc; i++){
983 lines2[i]= (AliStrLine*)lines->At(i);
985 AliESDVertex vert = TrackletVertexFinder(lines2,knacc,optUseWeights);
990 //---------------------------------------------------------------------------
991 AliESDVertex AliVertexerTracks::TrackletVertexFinder(AliStrLine **lines, const Int_t knacc, Int_t optUseWeights)
993 // Calculate the point at minimum distance to prepared tracks (array of AliStrLine)
995 Double_t initPos[3]={0.,0.,0.};
997 Double_t (*vectP0)[3]=new Double_t [knacc][3];
998 Double_t (*vectP1)[3]=new Double_t [knacc][3];
1001 Double_t dsum[3]={0,0,0};
1002 TMatrixD sumWi(3,3);
1003 for(Int_t i=0;i<3;i++){
1004 for(Int_t j=0;j<3;j++){
1010 for(Int_t i=0; i<knacc; i++){
1011 AliStrLine *line1 = lines[i];
1012 Double_t p0[3],cd[3],sigmasq[3];
1014 if(!line1) printf("ERROR %d %d\n",i,knacc);
1017 line1->GetSigma2P0(sigmasq);
1018 line1->GetWMatrix(wmat);
1021 for(Int_t ia=0;ia<3;ia++){
1022 for(Int_t ib=0;ib<3;ib++){
1023 wWi(ia,ib)=wmat[iel];
1030 Double_t p1[3]={p0[0]+cd[0],p0[1]+cd[1],p0[2]+cd[2]};
1038 Double_t matr[3][3];
1040 if(optUseWeights==0)GetStrLinDerivMatrix(p0,p1,matr,dknow);
1041 else GetStrLinDerivMatrix(p0,p1,sigmasq,matr,dknow);
1044 for(Int_t iii=0;iii<3;iii++){
1045 dsum[iii]+=dknow[iii];
1046 for(Int_t lj=0;lj<3;lj++) sum[iii][lj]+=matr[iii][lj];
1050 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
1051 Double_t covmatrix[6];
1052 covmatrix[0] = invsumWi(0,0);
1053 covmatrix[1] = invsumWi(0,1);
1054 covmatrix[2] = invsumWi(1,1);
1055 covmatrix[3] = invsumWi(0,2);
1056 covmatrix[4] = invsumWi(1,2);
1057 covmatrix[5] = invsumWi(2,2);
1059 Double_t vett[3][3];
1060 Double_t det=GetDeterminant3X3(sum);
1064 for(Int_t zz=0;zz<3;zz++){
1065 for(Int_t ww=0;ww<3;ww++){
1066 for(Int_t kk=0;kk<3;kk++) vett[ww][kk]=sum[ww][kk];
1068 for(Int_t kk=0;kk<3;kk++) vett[kk][zz]=dsum[kk];
1069 initPos[zz]=GetDeterminant3X3(vett)/det;
1073 for(Int_t i=0; i<knacc; i++){
1074 Double_t p0[3]={0,0,0},p1[3]={0,0,0};
1075 for(Int_t ii=0;ii<3;ii++){
1076 p0[ii]=vectP0[i][ii];
1077 p1[ii]=vectP1[i][ii];
1079 sigma+=GetStrLinMinDist(p0,p1,initPos);
1082 if(sigma>0.) {sigma=TMath::Sqrt(sigma);}else{sigma=999;}
1086 AliESDVertex theVert(initPos,covmatrix,99999.,knacc);
1087 theVert.SetDispersion(sigma);
1093 //---------------------------------------------------------------------------
1094 Bool_t AliVertexerTracks::TrackToPoint(AliExternalTrackParam *t,
1095 TMatrixD &ri,TMatrixD &wWi,
1096 Bool_t uUi3by3) const
1099 // Extract from the AliExternalTrackParam the global coordinates ri and covariance matrix
1100 // wWi of the space point that it represents (to be used in VertexFitter())
1104 Double_t rotAngle = t->GetAlpha();
1105 if(rotAngle<0.) rotAngle += 2.*TMath::Pi();
1106 Double_t cosRot = TMath::Cos(rotAngle);
1107 Double_t sinRot = TMath::Sin(rotAngle);
1109 ri(0,0) = t->GetX()*cosRot-t->GetY()*sinRot;
1110 ri(1,0) = t->GetX()*sinRot+t->GetY()*cosRot;
1111 ri(2,0) = t->GetZ();
1116 // matrix to go from global (x,y,z) to local (y,z);
1125 // covariance matrix of local (y,z) - inverted
1127 uUi(0,0) = t->GetSigmaY2();
1128 uUi(0,1) = t->GetSigmaZY();
1129 uUi(1,0) = t->GetSigmaZY();
1130 uUi(1,1) = t->GetSigmaZ2();
1132 //printf(" %f %f",uUi(0,0),uUi(0,1));
1133 //printf(" %f %f",uUi(1,0),uUi(1,1));
1135 if(uUi.Determinant() <= 0.) return kFALSE;
1136 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
1138 // weights matrix: wWi = qQiT * uUiInv * qQi
1139 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
1140 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
1143 if(fVert.GetNContributors()<1) AliFatal("Vertex from finder is empty");
1144 // matrix to go from global (x,y,z) to local (x,y,z);
1156 // covariance of fVert along the track
1157 Double_t p[3],pt,ptot;
1159 pt = TMath::Sqrt(p[0]*p[0]+p[1]*p[1]);
1160 ptot = TMath::Sqrt(pt*pt+p[2]*p[2]);
1161 Double_t cphi = p[0]/pt; //cos(phi)=px/pt
1162 Double_t sphi = p[1]/pt; //sin(phi)=py/pt
1163 Double_t clambda = pt/ptot; //cos(lambda)=pt/ptot
1164 Double_t slambda = p[2]/ptot; //sin(lambda)=pz/ptot
1165 Double_t covfVert[6];
1166 fVert.GetCovMatrix(covfVert);
1167 Double_t covfVertalongt =
1168 covfVert[0]*cphi*cphi*clambda*clambda
1169 +covfVert[1]*2.*cphi*sphi*clambda*clambda
1170 +covfVert[3]*2.*cphi*clambda*slambda
1171 +covfVert[2]*sphi*sphi*clambda*clambda
1172 +covfVert[4]*2.*sphi*clambda*slambda
1173 +covfVert[5]*slambda*slambda;
1174 // covariance matrix of local (x,y,z) - inverted
1176 uUi(0,0) = covfVertalongt * fnSigmaForUi00 * fnSigmaForUi00;
1177 AliDebug(1,Form("=====> sqrtUi00 cm %f",TMath::Sqrt(uUi(0,0))));
1181 uUi(1,1) = t->GetSigmaY2();
1182 uUi(1,2) = t->GetSigmaZY();
1184 uUi(2,1) = t->GetSigmaZY();
1185 uUi(2,2) = t->GetSigmaZ2();
1186 //printf(" Ui :\n");
1187 //printf(" %f %f\n",uUi(0,0),uUi(0,1));
1188 //printf(" %f %f\n",uUi(1,0),uUi(1,1));
1190 if(uUi.Determinant() <= 0.) return kFALSE;
1191 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
1193 // weights matrix: wWi = qQiT * uUiInv * qQi
1194 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
1195 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
1202 //---------------------------------------------------------------------------
1203 void AliVertexerTracks::TooFewTracks()
1206 // When the number of tracks is < fMinTracks,
1207 // deal with vertices not found and prepare to exit
1209 AliDebug(1,"TooFewTracks");
1211 Double_t pos[3],err[3];
1212 pos[0] = fNominalPos[0];
1213 err[0] = TMath::Sqrt(fNominalCov[0]);
1214 pos[1] = fNominalPos[1];
1215 err[1] = TMath::Sqrt(fNominalCov[2]);
1216 pos[2] = fNominalPos[2];
1217 err[2] = TMath::Sqrt(fNominalCov[5]);
1218 Int_t ncontr = (err[0]>1. ? -1 : -3);
1219 if(fCurrentVertex) { delete fCurrentVertex; fCurrentVertex=0; }
1220 fCurrentVertex = new AliESDVertex(pos,err);
1221 fCurrentVertex->SetNContributors(ncontr);
1224 fCurrentVertex->SetTitle("VertexerTracksWithConstraint");
1226 fCurrentVertex->SetTitle("VertexerTracksNoConstraint");
1229 if(!fTrkArraySel.IsEmpty()) fTrkArraySel.Delete();
1230 if(fIdSel) {delete [] fIdSel; fIdSel=NULL;}
1231 if(fTrksToSkip) {delete [] fTrksToSkip; fTrksToSkip=NULL;}
1235 //---------------------------------------------------------------------------
1236 void AliVertexerTracks::VertexFinder(Int_t optUseWeights)
1239 // Get estimate of vertex position in (x,y) from tracks DCA
1241 Double_t initPos[3];
1243 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
1244 Int_t nacc = (Int_t)fTrkArraySel.GetEntriesFast();
1245 Double_t aver[3]={0.,0.,0.};
1246 Double_t aversq[3]={0.,0.,0.};
1247 Double_t sigmasq[3]={0.,0.,0.};
1250 AliExternalTrackParam *track1;
1251 AliExternalTrackParam *track2;
1252 Double_t pos[3],dir[3];
1253 Double_t alpha,mindist;
1255 for(Int_t i=0; i<nacc; i++){
1256 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
1257 alpha=track1->GetAlpha();
1258 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1259 track1->GetXYZAt(mindist,GetFieldkG(),pos);
1260 track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
1261 AliStrLine *line1 = new AliStrLine(pos,dir);
1263 // AliStrLine *line1 = new AliStrLine();
1264 // track1->ApproximateHelixWithLine(mindist,GetFieldkG(),line1);
1266 for(Int_t j=i+1; j<nacc; j++){
1267 track2 = (AliExternalTrackParam*)fTrkArraySel.At(j);
1268 alpha=track2->GetAlpha();
1269 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1270 track2->GetXYZAt(mindist,GetFieldkG(),pos);
1271 track2->GetPxPyPzAt(mindist,GetFieldkG(),dir);
1272 AliStrLine *line2 = new AliStrLine(pos,dir);
1273 // AliStrLine *line2 = new AliStrLine();
1274 // track2->ApproximateHelixWithLine(mindist,GetFieldkG(),line2);
1275 Double_t distCA=line2->GetDCA(line1);
1276 //printf("%d %d %f\n",i,j,distCA);
1277 if(fDCAcut<=0 || (fDCAcut>0&&distCA<fDCAcut)){
1278 Double_t pnt1[3],pnt2[3],crosspoint[3];
1280 if(optUseWeights<=0){
1281 Int_t retcode = line2->Cross(line1,crosspoint);
1284 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
1285 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1288 if(optUseWeights>0){
1289 Int_t retcode = line1->CrossPoints(line2,pnt1,pnt2);
1292 alpha=track1->GetAlpha();
1293 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
1294 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
1295 alpha=track2->GetAlpha();
1296 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
1297 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
1298 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
1299 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
1300 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
1301 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
1302 crosspoint[0]=wx1*pnt1[0] + wx2*pnt2[0];
1303 crosspoint[1]=wy1*pnt1[1] + wy2*pnt2[1];
1304 crosspoint[2]=wz1*pnt1[2] + wz2*pnt2[2];
1307 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
1308 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1317 for(Int_t jj=0;jj<3;jj++){
1318 initPos[jj] = aver[jj]/ncombi;
1319 //printf("%f\n",initPos[jj]);
1321 sigmasq[jj]=aversq[jj]-initPos[jj]*initPos[jj];
1324 sigma=TMath::Sqrt(TMath::Abs(sigma));
1327 Warning("VertexFinder","Finder did not succed");
1330 fVert.SetXYZ(initPos);
1331 fVert.SetDispersion(sigma);
1332 fVert.SetNContributors(ncombi);
1334 //---------------------------------------------------------------------------
1335 void AliVertexerTracks::VertexFitter()
1338 // The optimal estimate of the vertex position is given by a "weighted
1339 // average of tracks positions".
1340 // Original method: V. Karimaki, CMS Note 97/0051
1342 Bool_t useConstraint = fConstraint;
1343 Double_t initPos[3];
1345 fVert.GetXYZ(initPos);
1347 initPos[0]=fNominalPos[0];
1348 initPos[1]=fNominalPos[1];
1349 initPos[2]=fNominalPos[2];
1352 Int_t nTrksSel = (Int_t)fTrkArraySel.GetEntries();
1353 if(nTrksSel==1) useConstraint=kTRUE;
1354 AliDebug(1,"--- VertexFitter(): start");
1355 AliDebug(1,Form(" Number of tracks in array: %d\n",nTrksSel));
1356 AliDebug(1,Form(" Minimum # tracks required in fit: %d\n",fMinTracks));
1357 AliDebug(1,Form(" Vertex position after finder: %f,%f,%f\n",initPos[0],initPos[1],initPos[2]));
1358 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])));
1360 // special treatment for few-tracks fits (e.g. secondary vertices)
1361 Bool_t uUi3by3 = kFALSE; if(nTrksSel<5 && !useConstraint) uUi3by3 = kTRUE;
1366 rv(0,0) = initPos[0];
1367 rv(1,0) = initPos[1];
1369 Double_t xlStart,alpha;
1371 Double_t chi2,chi2i,chi2b;
1372 AliExternalTrackParam *t = 0;
1375 // initial vertex covariance matrix
1377 vVb(0,0) = fNominalCov[0];
1378 vVb(0,1) = fNominalCov[1];
1380 vVb(1,0) = fNominalCov[1];
1381 vVb(1,1) = fNominalCov[2];
1385 vVb(2,2) = fNominalCov[5];
1386 TMatrixD vVbInv(TMatrixD::kInverted,vVb);
1388 rb(0,0) = fNominalPos[0];
1389 rb(1,0) = fNominalPos[1];
1390 rb(2,0) = fNominalPos[2];
1391 TMatrixD vVbInvrb(vVbInv,TMatrixD::kMult,rb);
1395 // 1st - estimate of vtx using all tracks
1396 // 2nd - estimate of global chi2
1397 for(step=0; step<2; step++) {
1398 AliDebug(1,Form(" step = %d\n",step));
1402 if(step==1) { initPos[0]=rv(0,0); initPos[0]=rv(1,0); }
1404 TMatrixD sumWiri(3,1);
1405 TMatrixD sumWi(3,3);
1406 for(i=0; i<3; i++) {
1408 for(j=0; j<3; j++) sumWi(j,i) = 0.;
1411 // mean vertex constraint
1414 sumWiri(i,0) += vVbInvrb(i,0);
1415 for(k=0;k<3;k++) sumWi(i,k) += vVbInv(i,k);
1418 TMatrixD deltar = rv; deltar -= rb;
1419 TMatrixD vVbInvdeltar(vVbInv,TMatrixD::kMult,deltar);
1420 chi2b = deltar(0,0)*vVbInvdeltar(0,0)+
1421 deltar(1,0)*vVbInvdeltar(1,0)+
1422 deltar(2,0)*vVbInvdeltar(2,0);
1427 for(k=0; k<nTrksSel; k++) {
1428 // get track from track array
1429 t = (AliExternalTrackParam*)fTrkArraySel.At(k);
1430 alpha = t->GetAlpha();
1431 xlStart = initPos[0]*TMath::Cos(alpha)+initPos[1]*TMath::Sin(alpha);
1432 // to vtxSeed (from finder)
1433 t->PropagateTo(xlStart,GetFieldkG());
1435 // vector of track global coordinates
1437 // covariance matrix of ri
1440 // get space point from track
1441 if(!TrackToPoint(t,ri,wWi,uUi3by3)) continue;
1442 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
1445 TMatrixD deltar = rv; deltar -= ri;
1446 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
1447 chi2i = deltar(0,0)*wWideltar(0,0)+
1448 deltar(1,0)*wWideltar(1,0)+
1449 deltar(2,0)*wWideltar(2,0);
1451 // add to total chi2
1458 } // end loop on tracks
1460 if(nTrksUsed < fMinTracks) {
1465 Double_t determinant = sumWi.Determinant();
1466 if(determinant < fMinDetFitter) {
1467 AliDebug(1,Form("det(V) = %f (<%f)\n",determinant,fMinDetFitter));
1473 // inverted of weights matrix
1474 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
1476 // position of primary vertex
1477 rv.Mult(vV,sumWiri);
1479 } // end loop on the 2 steps
1486 Double_t position[3];
1487 position[0] = rv(0,0);
1488 position[1] = rv(1,0);
1489 position[2] = rv(2,0);
1490 Double_t covmatrix[6];
1491 covmatrix[0] = vV(0,0);
1492 covmatrix[1] = vV(0,1);
1493 covmatrix[2] = vV(1,1);
1494 covmatrix[3] = vV(0,2);
1495 covmatrix[4] = vV(1,2);
1496 covmatrix[5] = vV(2,2);
1498 // for correct chi2/ndf, count constraint as additional "track"
1499 if(fConstraint) nTrksUsed++;
1500 // store data in the vertex object
1501 if(fCurrentVertex) { delete fCurrentVertex; fCurrentVertex=0; }
1502 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nTrksUsed);
1504 AliDebug(1," Vertex after fit:");
1505 AliDebug(1,Form("xyz: %f %f %f; nc %d",fCurrentVertex->GetXv(),fCurrentVertex->GetYv(),fCurrentVertex->GetZv(),fCurrentVertex->GetNContributors()));
1506 AliDebug(1,"--- VertexFitter(): finish\n");
1511 //----------------------------------------------------------------------------
1512 AliESDVertex* AliVertexerTracks::VertexForSelectedTracks(TObjArray *trkArray,
1514 Bool_t optUseFitter,
1515 Bool_t optPropagate)
1518 // Return vertex from tracks (AliExternalTrackParam) in array
1523 // get tracks and propagate them to initial vertex position
1524 fIdSel = new UShort_t[(Int_t)trkArray->GetEntriesFast()];
1525 Int_t nTrksSel = PrepareTracks(*trkArray,id,0);
1526 if(nTrksSel < TMath::Max(2,fMinTracks)) {
1528 return fCurrentVertex;
1533 case 1: StrLinVertexFinderMinDist(1); break;
1534 case 2: StrLinVertexFinderMinDist(0); break;
1535 case 3: HelixVertexFinder(); break;
1536 case 4: VertexFinder(1); break;
1537 case 5: VertexFinder(0); break;
1538 default: printf("Wrong algorithm\n"); break;
1540 AliDebug(1," Vertex finding completed\n");
1546 Double_t position[3]={fVert.GetXv(),fVert.GetYv(),fVert.GetZv()};
1547 Double_t covmatrix[6];
1548 fVert.GetCovMatrix(covmatrix);
1549 Double_t chi2=99999.;
1550 Int_t nTrksUsed=fVert.GetNContributors();
1551 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nTrksUsed);
1553 fCurrentVertex->SetDispersion(fVert.GetDispersion());
1556 // set indices of used tracks and propagate track to found vertex
1557 UShort_t *indices = 0;
1558 Double_t d0z0[2],covd0z0[3];
1559 AliExternalTrackParam *t = 0;
1560 if(fCurrentVertex->GetNContributors()>0) {
1561 indices = new UShort_t[fCurrentVertex->GetNContributors()];
1562 for(Int_t jj=0; jj<(Int_t)fTrkArraySel.GetEntriesFast(); jj++) {
1563 indices[jj] = fIdSel[jj];
1564 t = (AliExternalTrackParam*)fTrkArraySel.At(jj);
1565 if(optPropagate && optUseFitter) {
1566 if(TMath::Sqrt(fCurrentVertex->GetXv()*fCurrentVertex->GetXv()+fCurrentVertex->GetYv()*fCurrentVertex->GetYv())<3.) {
1567 t->PropagateToDCA(fCurrentVertex,GetFieldkG(),100.,d0z0,covd0z0);
1568 AliDebug(1,Form("Track %d propagated to found vertex",jj));
1570 AliWarning("Found vertex outside beam pipe!");
1574 fCurrentVertex->SetIndices(fCurrentVertex->GetNContributors(),indices);
1578 delete [] indices; indices=NULL;
1579 delete [] fIdSel; fIdSel=NULL;
1580 fTrkArraySel.Delete();
1582 return fCurrentVertex;
1584 //----------------------------------------------------------------------------
1585 AliESDVertex* AliVertexerTracks::VertexForSelectedESDTracks(TObjArray *trkArray,
1586 Bool_t optUseFitter,
1587 Bool_t optPropagate)
1590 // Return vertex from array of ESD tracks
1593 Int_t nTrks = (Int_t)trkArray->GetEntriesFast();
1594 UShort_t *id = new UShort_t[nTrks];
1596 AliESDtrack *esdt = 0;
1597 for(Int_t i=0; i<nTrks; i++){
1598 esdt = (AliESDtrack*)trkArray->At(i);
1599 id[i] = (UShort_t)esdt->GetID();
1602 VertexForSelectedTracks(trkArray,id,optUseFitter,optPropagate);
1604 delete [] id; id=NULL;
1606 return fCurrentVertex;
1608 //--------------------------------------------------------------------------