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():
76 // Default constructor
81 //----------------------------------------------------------------------------
82 AliVertexerTracks::AliVertexerTracks(Double_t fieldkG):
110 // Standard constructor
115 //-----------------------------------------------------------------------------
116 AliVertexerTracks::~AliVertexerTracks()
118 // Default Destructor
119 // The objects pointed by the following pointer are not owned
120 // by this class and are not deleted
122 if(fTrksToSkip) { delete [] fTrksToSkip; fTrksToSkip=NULL; }
123 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
125 //----------------------------------------------------------------------------
126 AliESDVertex* AliVertexerTracks::FindPrimaryVertex(const AliVEvent *vEvent)
129 // Primary vertex for current ESD or AOD event
131 // 1st with 5*fNSigma*sigma cut w.r.t. to initial vertex
132 // + cut on sqrt(d0d0+z0z0) if fConstraint=kFALSE
133 // 2nd with fNSigma*sigma cut w.r.t. to vertex found in 1st iteration)
137 TString evtype = vEvent->IsA()->GetName();
138 Bool_t inputAOD = ((evtype=="AliAODEvent") ? kTRUE : kFALSE);
140 if(inputAOD && fMode==1) {
141 printf("Error : AliVertexerTracks: no TPC-only vertex from AOD\n");
143 return fCurrentVertex;
146 // accept 1-track case only if constraint is available
147 if(!fConstraint && fMinTracks==1) fMinTracks=2;
149 // read tracks from AlivEvent
150 Int_t nTrks = (Int_t)vEvent->GetNumberOfTracks();
151 if(nTrks<fMinTracks) {
153 return fCurrentVertex;
157 TDirectory * olddir = gDirectory;
159 if(nTrks>500) f = new TFile("VertexerTracks.root","recreate");
160 TObjArray trkArrayOrig(nTrks);
161 UShort_t *idOrig = new UShort_t[nTrks];
164 AliExternalTrackParam *t=0;
166 for(Int_t i=0; i<nTrks; i++) {
167 AliVTrack *track = (AliVTrack*)vEvent->GetTrack(i);
168 // check tracks to skip
169 Bool_t skipThis = kFALSE;
170 for(Int_t j=0; j<fNTrksToSkip; j++) {
171 if(track->GetID()==fTrksToSkip[j]) {
172 AliDebug(1,Form("skipping track: %d",i));
176 if(skipThis) continue;
178 if(!inputAOD) { // ESD
179 AliESDtrack* esdt = (AliESDtrack*)track;
180 if(esdt->GetNcls(fMode) < fMinClusters) continue;
181 if(fMode==0) { // ITS mode
182 if(fITSrefit && !(esdt->GetStatus()&AliESDtrack::kITSrefit)) continue;
183 Double_t x,p[5],cov[15];
184 esdt->GetExternalParameters(x,p);
185 esdt->GetExternalCovariance(cov);
186 t = new AliExternalTrackParam(x,esdt->GetAlpha(),p,cov);
187 } else if(fMode==1) { // TPC mode
188 t = (AliExternalTrackParam*)esdt->GetTPCInnerParam();
190 Double_t radius = 2.8; //something less than the beam pipe radius
191 if(!PropagateTrackTo(t,radius)) continue;
193 } else { // AOD (only ITS mode)
195 for(Int_t l=0;l<6;l++) if(TESTBIT(track->GetITSClusterMap(),l)) ncls0++;
196 if(ncls0 < fMinClusters) continue;
197 t = new AliExternalTrackParam(track);
199 trkArrayOrig.AddLast(t);
200 idOrig[nTrksOrig]=(UShort_t)track->GetID();
202 } // end loop on tracks
204 // call method that will reconstruct the vertex
205 FindPrimaryVertex(&trkArrayOrig,idOrig);
207 if(fMode==0) trkArrayOrig.Delete();
208 delete [] idOrig; idOrig=NULL;
211 f->Close(); delete f; f = NULL;
212 gSystem->Unlink("VertexerTracks.root");
216 return fCurrentVertex;
218 //----------------------------------------------------------------------------
219 AliESDVertex* AliVertexerTracks::FindPrimaryVertex(TObjArray *trkArrayOrig,
223 // Primary vertex using the AliExternalTrackParam's in the TObjArray.
224 // idOrig must contain the track IDs from AliESDtrack::GetID()
226 // 1st with 5*fNSigma*sigma cut w.r.t. to initial vertex
227 // + cut on sqrt(d0d0+z0z0) if fConstraint=kFALSE
228 // 2nd with fNSigma*sigma cut w.r.t. to vertex found in 1st iteration)
232 // accept 1-track case only if constraint is available
233 if(!fConstraint && fMinTracks==1) fMinTracks=2;
235 // read tracks from array
236 Int_t nTrksOrig = (Int_t)trkArrayOrig->GetEntriesFast();
237 AliDebug(1,Form("Initial number of tracks: %d",nTrksOrig));
238 if(nTrksOrig<fMinTracks) {
239 AliDebug(1,"TooFewTracks");
241 return fCurrentVertex;
244 // If fConstraint=kFALSE
245 // run VertexFinder(1) to get rough estimate of initVertex (x,y)
247 // fill fTrkArraySel, for VertexFinder()
248 fIdSel = new UShort_t[nTrksOrig];
249 PrepareTracks(*trkArrayOrig,idOrig,0);
250 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
251 Double_t cutsave = fDCAcut;
252 fDCAcut = fDCAcutIter0;
254 switch (fAlgoIter0) {
255 case 1: StrLinVertexFinderMinDist(1); break;
256 case 2: StrLinVertexFinderMinDist(0); break;
257 case 3: HelixVertexFinder(); break;
258 case 4: VertexFinder(1); break;
259 case 5: VertexFinder(0); break;
260 default: printf("Wrong algorithm\n"); break;
263 if(fVert.GetNContributors()>0) {
264 fVert.GetXYZ(fNominalPos);
265 fNominalPos[0] = fVert.GetXv();
266 fNominalPos[1] = fVert.GetYv();
267 fNominalPos[2] = fVert.GetZv();
268 AliDebug(1,Form("No mean vertex: VertexFinder gives (%f, %f, %f)",fNominalPos[0],fNominalPos[1],fNominalPos[2]));
273 AliDebug(1,"No mean vertex and VertexFinder failed");
280 // propagate tracks to fNominalPos vertex
282 // if(constraint) reject for |d0|>5*fNSigma*sigma w.r.t. fNominal... vertex
283 // else reject for |d0|\oplus|z0| > 5 mm w.r.t. fNominal... vertex
285 // propagate tracks to best between initVertex and fCurrentVertex
286 // preselect tracks (reject for |d0|>fNSigma*sigma w.r.t. best
287 // between initVertex and fCurrentVertex)
288 for(Int_t iter=1; iter<=2; iter++) {
289 if(fOnlyFitter && iter==1) continue;
290 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
291 fIdSel = new UShort_t[nTrksOrig];
292 Int_t nTrksSel = PrepareTracks(*trkArrayOrig,idOrig,iter);
293 AliDebug(1,Form("N tracks selected in iteration %d: %d",iter,nTrksSel));
294 if(nTrksSel < fMinTracks) {
296 return fCurrentVertex;
302 AliDebug(1,"Just one track");
303 OneTrackVertFinder();
306 case 1: StrLinVertexFinderMinDist(1); break;
307 case 2: StrLinVertexFinderMinDist(0); break;
308 case 3: HelixVertexFinder(); break;
309 case 4: VertexFinder(1); break;
310 case 5: VertexFinder(0); break;
311 default: printf("Wrong algorithm"); break;
314 AliDebug(1," Vertex finding completed");
319 } // end loop on the two iterations
322 // set indices of used tracks
323 UShort_t *indices = 0;
324 if(fCurrentVertex->GetNContributors()>0) {
325 Int_t nIndices = (Int_t)fTrkArraySel.GetEntriesFast();
326 indices = new UShort_t[nIndices];
327 for(Int_t jj=0; jj<nIndices; jj++)
328 indices[jj] = fIdSel[jj];
329 fCurrentVertex->SetIndices(nIndices,indices);
331 delete [] indices; indices=NULL;
335 TString title="VertexerTracksNoConstraint";
337 title="VertexerTracksWithConstraint";
338 if(fOnlyFitter) title.Append("OnlyFitter");
340 fCurrentVertex->SetTitle(title.Data());
343 AliDebug(1,Form("xyz: %f %f %f; nc %d",fCurrentVertex->GetXv(),fCurrentVertex->GetYv(),fCurrentVertex->GetZv(),fCurrentVertex->GetNContributors()));
346 delete [] fIdSel; fIdSel=NULL;
347 fTrkArraySel.Delete();
348 if(fTrksToSkip) { delete [] fTrksToSkip; fTrksToSkip=NULL; }
351 return fCurrentVertex;
353 //------------------------------------------------------------------------
354 Double_t AliVertexerTracks::GetDeterminant3X3(Double_t matr[][3])
357 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];
360 //-------------------------------------------------------------------------
361 void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t (*m)[3],Double_t *d)
364 Double_t x12=p0[0]-p1[0];
365 Double_t y12=p0[1]-p1[1];
366 Double_t z12=p0[2]-p1[2];
367 Double_t kk=x12*x12+y12*y12+z12*z12;
368 m[0][0]=2-2/kk*x12*x12;
369 m[0][1]=-2/kk*x12*y12;
370 m[0][2]=-2/kk*x12*z12;
371 m[1][0]=-2/kk*x12*y12;
372 m[1][1]=2-2/kk*y12*y12;
373 m[1][2]=-2/kk*y12*z12;
374 m[2][0]=-2/kk*x12*z12;
376 m[2][2]=2-2/kk*z12*z12;
377 d[0]=2*p0[0]-2/kk*p0[0]*x12*x12-2/kk*p0[2]*x12*z12-2/kk*p0[1]*x12*y12;
378 d[1]=2*p0[1]-2/kk*p0[1]*y12*y12-2/kk*p0[0]*x12*y12-2/kk*p0[2]*z12*y12;
379 d[2]=2*p0[2]-2/kk*p0[2]*z12*z12-2/kk*p0[0]*x12*z12-2/kk*p0[1]*z12*y12;
382 //--------------------------------------------------------------------------
383 void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t *sigmasq,Double_t (*m)[3],Double_t *d)
386 Double_t x12=p1[0]-p0[0];
387 Double_t y12=p1[1]-p0[1];
388 Double_t z12=p1[2]-p0[2];
390 Double_t den= x12*x12*sigmasq[1]*sigmasq[2]+y12*y12*sigmasq[0]*sigmasq[2]+z12*z12*sigmasq[0]*sigmasq[1];
392 Double_t kk= 2*(x12*x12/sigmasq[0]+y12*y12/sigmasq[1]+z12*z12/sigmasq[2]);
395 cc[0]=-x12/sigmasq[0];
396 cc[1]=-y12/sigmasq[1];
397 cc[2]=-z12/sigmasq[2];
399 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;
401 Double_t ss= -p0[0]*cc[0]-p0[1]*cc[1]-p0[2]*cc[2];
404 aa[0]=x12*sigmasq[1]*sigmasq[2]/den;
405 aa[1]=y12*sigmasq[0]*sigmasq[2]/den;
406 aa[2]=z12*sigmasq[0]*sigmasq[1]/den;
408 m[0][0]=aa[0]*(aa[0]*kk+2*cc[0])+2*cc[0]*aa[0]+2/sigmasq[0];
409 m[0][1]=aa[1]*(aa[0]*kk+2*cc[0])+2*cc[1]*aa[0];
410 m[0][2]=aa[2]*(aa[0]*kk+2*cc[0])+2*cc[2]*aa[0];
412 m[1][0]=aa[0]*(aa[1]*kk+2*cc[1])+2*cc[0]*aa[1];
413 m[1][1]=aa[1]*(aa[1]*kk+2*cc[1])+2*cc[1]*aa[1]+2/sigmasq[1];
414 m[1][2]=aa[2]*(aa[1]*kk+2*cc[1])+2*cc[2]*aa[1];
416 m[2][0]=aa[0]*(aa[2]*kk+2*cc[2])+2*cc[0]*aa[2];
417 m[2][1]=aa[1]*(aa[2]*kk+2*cc[2])+2*cc[1]*aa[2];
418 m[2][2]=aa[2]*(aa[2]*kk+2*cc[2])+2*cc[2]*aa[2]+2/sigmasq[2];
420 d[0]=-ww*(aa[0]*kk+2*cc[0])-2*ss*aa[0]+2*p0[0]/sigmasq[0];
421 d[1]=-ww*(aa[1]*kk+2*cc[1])-2*ss*aa[1]+2*p0[1]/sigmasq[1];
422 d[2]=-ww*(aa[2]*kk+2*cc[2])-2*ss*aa[2]+2*p0[2]/sigmasq[2];
425 //--------------------------------------------------------------------------
426 Double_t AliVertexerTracks::GetStrLinMinDist(Double_t *p0,Double_t *p1,Double_t *x0)
429 Double_t x12=p0[0]-p1[0];
430 Double_t y12=p0[1]-p1[1];
431 Double_t z12=p0[2]-p1[2];
432 Double_t x10=p0[0]-x0[0];
433 Double_t y10=p0[1]-x0[1];
434 Double_t z10=p0[2]-x0[2];
435 // 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);
436 return ((y10*z12-z10*y12)*(y10*z12-z10*y12)+
437 (z10*x12-x10*z12)*(z10*x12-x10*z12)+
438 (x10*y12-y10*x12)*(x10*y12-y10*x12))
439 /(x12*x12+y12*y12+z12*z12);
441 //---------------------------------------------------------------------------
442 void AliVertexerTracks::OneTrackVertFinder()
444 // find vertex for events with 1 track, using DCA to nominal beam axis
445 AliDebug(1,Form("Number of prepared tracks =%d - Call OneTrackVertFinder",fTrkArraySel.GetEntries()));
446 AliExternalTrackParam *track1;
447 track1 = (AliExternalTrackParam*)fTrkArraySel.At(0);
448 Double_t alpha=track1->GetAlpha();
449 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
450 Double_t pos[3],dir[3];
451 track1->GetXYZAt(mindist,GetFieldkG(),pos);
452 track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
453 AliStrLine *line1 = new AliStrLine(pos,dir);
454 Double_t p1[3]={fNominalPos[0],fNominalPos[1],0.};
455 Double_t p2[3]={fNominalPos[0],fNominalPos[1],10.};
456 AliStrLine *zeta=new AliStrLine(p1,p2,kTRUE);
457 Double_t crosspoint[3]={0.,0.,0.};
460 Int_t retcode = zeta->Cross(line1,crosspoint);
462 sigma=line1->GetDistFromPoint(crosspoint);
467 fVert.SetXYZ(crosspoint);
468 fVert.SetDispersion(sigma);
469 fVert.SetNContributors(nContrib);
471 //---------------------------------------------------------------------------
472 void AliVertexerTracks::HelixVertexFinder()
474 // Get estimate of vertex position in (x,y) from tracks DCA
479 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
481 Int_t nacc = (Int_t)fTrkArraySel.GetEntriesFast();
483 Double_t aver[3]={0.,0.,0.};
484 Double_t averquad[3]={0.,0.,0.};
485 Double_t sigmaquad[3]={0.,0.,0.};
488 AliExternalTrackParam *track1;
489 AliExternalTrackParam *track2;
492 Double_t alpha, cs, sn;
493 Double_t crosspoint[3];
494 for(Int_t i=0; i<nacc; i++){
495 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
498 for(Int_t j=i+1; j<nacc; j++){
499 track2 = (AliExternalTrackParam*)fTrkArraySel.At(j);
501 distCA=track2->PropagateToDCA(track1,GetFieldkG());
502 if(fDCAcut<=0 ||(fDCAcut>0&&distCA<fDCAcut)){
504 alpha=track1->GetAlpha();
505 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
506 Double_t x1=x*cs - track1->GetY()*sn;
507 Double_t y1=x*sn + track1->GetY()*cs;
508 Double_t z1=track1->GetZ();
510 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
512 alpha=track2->GetAlpha();
513 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
514 Double_t x2=x*cs - track2->GetY()*sn;
515 Double_t y2=x*sn + track2->GetY()*cs;
516 Double_t z2=track2->GetZ();
517 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
518 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
519 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
520 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
521 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
522 crosspoint[0]=wx1*x1 + wx2*x2;
523 crosspoint[1]=wy1*y1 + wy2*y2;
524 crosspoint[2]=wz1*z1 + wz2*z2;
527 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
528 for(Int_t jj=0;jj<3;jj++)averquad[jj]+=(crosspoint[jj]*crosspoint[jj]);
534 for(Int_t jj=0;jj<3;jj++){
535 initPos[jj] = aver[jj]/ncombi;
536 averquad[jj]/=ncombi;
537 sigmaquad[jj]=averquad[jj]-initPos[jj]*initPos[jj];
538 sigma+=sigmaquad[jj];
540 sigma=TMath::Sqrt(TMath::Abs(sigma));
543 Warning("HelixVertexFinder","Finder did not succed");
546 fVert.SetXYZ(initPos);
547 fVert.SetDispersion(sigma);
548 fVert.SetNContributors(ncombi);
550 //----------------------------------------------------------------------------
551 Int_t AliVertexerTracks::PrepareTracks(TObjArray &trkArrayOrig,
556 // Propagate tracks to initial vertex position and store them in a TObjArray
558 AliDebug(1," PrepareTracks()");
560 Int_t nTrksOrig = (Int_t)trkArrayOrig.GetEntriesFast();
563 Double_t sigmaCurr[3];
564 Double_t normdistx,normdisty;
565 Double_t d0z0[2],covd0z0[3];
568 AliESDVertex *initVertex = new AliESDVertex(fNominalPos,fNominalCov,1,1);
570 if(!fTrkArraySel.IsEmpty()) fTrkArraySel.Delete();
572 AliExternalTrackParam *track=0;
575 for(Int_t i=0; i<nTrksOrig; i++) {
576 track = new AliExternalTrackParam(*(AliExternalTrackParam*)trkArrayOrig.At(i));
578 if(TMath::Abs(track->GetTgl())>fMaxTgl) {
579 AliDebug(1,Form(" rejecting track with tgl = %f",track->GetTgl()));
580 delete track; continue;
583 Bool_t propagateOK = kFALSE;
584 // propagate track to vertex
585 if(optImpParCut<2 || fOnlyFitter) { // optImpParCut==1 or 0
586 propagateOK = track->PropagateToDCA(initVertex,GetFieldkG(),100.,d0z0,covd0z0);
587 } else { // optImpParCut==2
588 fCurrentVertex->GetSigmaXYZ(sigmaCurr);
589 normdistx = TMath::Abs(fCurrentVertex->GetXv()-fNominalPos[0])/TMath::Sqrt(sigmaCurr[0]*sigmaCurr[0]+fNominalCov[0]);
590 normdisty = TMath::Abs(fCurrentVertex->GetYv()-fNominalPos[1])/TMath::Sqrt(sigmaCurr[1]*sigmaCurr[1]+fNominalCov[2]);
591 if(normdistx < 3. && normdisty < 3. &&
592 (sigmaCurr[0]+sigmaCurr[1])<(TMath::Sqrt(fNominalCov[0])+TMath::Sqrt(fNominalCov[2]))) {
593 propagateOK = track->PropagateToDCA(fCurrentVertex,GetFieldkG(),100.,d0z0,covd0z0);
595 propagateOK = track->PropagateToDCA(initVertex,GetFieldkG(),100.,d0z0,covd0z0);
600 AliDebug(1," rejected");
601 delete track; continue;
604 sigmad0 = TMath::Sqrt(covd0z0[0]);
605 maxd0rphi = fNSigma*sigmad0;
606 if(optImpParCut==1) maxd0rphi *= 5.;
607 maxd0rphi = TMath::Min(maxd0rphi,fFiducialR);
608 //sigmad0z0 = TMath::Sqrt(covd0z0[0]+covd0z0[2]); // for future improvement
609 //maxd0z0 = 10.*fNSigma*sigmad0z0;
611 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));
614 //---- track selection based on impact parameters ----//
616 // always reject tracks outside fiducial volume
617 if(TMath::Abs(d0z0[0])>fFiducialR || TMath::Abs(d0z0[1])>fFiducialZ) {
618 AliDebug(1," rejected");
619 delete track; continue;
622 // during iterations 1 and 2 , reject tracks with d0rphi > maxd0rphi
623 if(optImpParCut>0 && TMath::Abs(d0z0[0])>maxd0rphi) {
624 AliDebug(1," rejected");
625 delete track; continue;
628 // if fConstraint=kFALSE, during iterations 1 and 2 ||
629 // if fConstraint=kTRUE, during iteration 2,
630 // select tracks with d0oplusz0 < fMaxd0z0
631 if((!fConstraint && optImpParCut>0 && fVert.GetNContributors()>0) ||
632 ( fConstraint && optImpParCut==2)) {
634 TMath::Sqrt(d0z0[0]*d0z0[0]+d0z0[1]*d0z0[1])>fMaxd0z0) {
635 AliDebug(1," rejected");
636 delete track; continue;
640 // track passed all selections
641 fTrkArraySel.AddLast(track);
642 fIdSel[nTrksSel] = idOrig[i];
644 } // end loop on tracks
650 //----------------------------------------------------------------------------
651 Bool_t AliVertexerTracks::PropagateTrackTo(AliExternalTrackParam *track,
653 //----------------------------------------------------------------
654 // COPIED from AliTracker
656 // Propagates the track to the plane X=xk (cm).
658 // Origin: Marian Ivanov, Marian.Ivanov@cern.ch
659 //----------------------------------------------------------------
661 const Double_t kEpsilon = 0.00001;
662 Double_t xpos = track->GetX();
663 Double_t dir = (xpos<xToGo) ? 1. : -1.;
664 Double_t maxStep = 5;
665 Double_t maxSnp = 0.8;
667 while ( (xToGo-xpos)*dir > kEpsilon){
668 Double_t step = dir*TMath::Min(TMath::Abs(xToGo-xpos), maxStep);
669 Double_t x = xpos+step;
670 Double_t xyz0[3],xyz1[3];
671 track->GetXYZ(xyz0); //starting global position
673 if(!track->GetXYZAt(x,GetFieldkG(),xyz1)) return kFALSE; // no prolongation
674 xyz1[2]+=kEpsilon; // waiting for bug correction in geo
676 if(TMath::Abs(track->GetSnpAt(x,GetFieldkG())) >= maxSnp) return kFALSE;
677 if(!track->PropagateTo(x,GetFieldkG())) return kFALSE;
679 if(TMath::Abs(track->GetSnp()) >= maxSnp) return kFALSE;
680 track->GetXYZ(xyz0); // global position
681 Double_t alphan = TMath::ATan2(xyz0[1], xyz0[0]);
683 Double_t ca=TMath::Cos(alphan-track->GetAlpha()),
684 sa=TMath::Sin(alphan-track->GetAlpha());
685 Double_t sf=track->GetSnp(), cf=TMath::Sqrt(1.- sf*sf);
686 Double_t sinNew = sf*ca - cf*sa;
687 if(TMath::Abs(sinNew) >= maxSnp) return kFALSE;
688 if(!track->Rotate(alphan)) return kFALSE;
690 xpos = track->GetX();
694 //---------------------------------------------------------------------------
695 AliESDVertex* AliVertexerTracks::RemoveTracksFromVertex(AliESDVertex *inVtx,
701 // Removes tracks in trksTree from fit of inVtx
704 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraint")) {
705 printf("ERROR: primary vertex has no constraint: cannot remove tracks");
708 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraintOnlyFitter"))
709 printf("WARNING: result of tracks' removal will be only approximately correct");
712 rv(0,0) = inVtx->GetXv();
713 rv(1,0) = inVtx->GetYv();
714 rv(2,0) = inVtx->GetZv();
717 inVtx->GetCovMatrix(cov);
719 vV(0,1) = cov[1]; vV(1,0) = cov[1];
721 vV(0,2) = cov[3]; vV(2,0) = cov[3];
722 vV(1,2) = cov[4]; vV(2,1) = cov[4];
725 TMatrixD sumWi(TMatrixD::kInverted,vV);
726 TMatrixD sumWiri(sumWi,TMatrixD::kMult,rv);
728 Int_t nUsedTrks = inVtx->GetNIndices();
729 Double_t chi2 = inVtx->GetChi2();
731 AliExternalTrackParam *track = 0;
732 Int_t ntrks = (Int_t)trkArray->GetEntriesFast();
733 for(Int_t i=0;i<ntrks;i++) {
734 track = (AliExternalTrackParam*)trkArray->At(i);
735 if(!inVtx->UsesTrack(id[i])) {
736 printf("track %d was not used in vertex fit",id[i]);
739 Double_t alpha = track->GetAlpha();
740 Double_t xl = diamondxy[0]*TMath::Cos(alpha)+diamondxy[1]*TMath::Sin(alpha);
741 track->PropagateTo(xl,GetFieldkG());
742 // vector of track global coordinates
744 // covariance matrix of ri
747 // get space point from track
748 if(!TrackToPoint(track,ri,wWi)) continue;
750 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
756 TMatrixD deltar = rv; deltar -= ri;
757 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
758 Double_t chi2i = deltar(0,0)*wWideltar(0,0)+
759 deltar(1,0)*wWideltar(1,0)+
760 deltar(2,0)*wWideltar(2,0);
761 // remove from total chi2
766 printf("Trying to remove too many tracks!");
774 // new inverted of weights matrix
775 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
777 // new position of primary vertex
778 rvnew.Mult(vVnew,sumWiri);
780 Double_t position[3];
781 position[0] = rvnew(0,0);
782 position[1] = rvnew(1,0);
783 position[2] = rvnew(2,0);
791 // store data in the vertex object
792 AliESDVertex *outVtx = new AliESDVertex(position,cov,chi2,nUsedTrks);
793 outVtx->SetTitle(inVtx->GetTitle());
794 UShort_t *inindices = inVtx->GetIndices();
795 Int_t nIndices = nUsedTrks;
796 UShort_t *outindices = new UShort_t[nIndices];
798 for(Int_t k=0; k<inVtx->GetNIndices(); k++) {
799 Bool_t copyindex=kTRUE;
800 for(Int_t l=0; l<ntrks; l++) {
801 if(inindices[k]==id[l]) copyindex=kFALSE;
804 outindices[j] = inindices[k]; j++;
807 outVtx->SetIndices(nIndices,outindices);
808 delete [] outindices;
811 printf("Vertex before removing tracks:");
812 inVtx->PrintStatus();
813 inVtx->PrintIndices();
814 printf("Vertex after removing tracks:");
815 outVtx->PrintStatus();
816 outVtx->PrintIndices();
821 //---------------------------------------------------------------------------
822 void AliVertexerTracks::SetCuts(Double_t *cuts)
828 SetDCAcutIter0(cuts[1]);
830 if(fMode==0 && cuts[3]<0) SetITSrefitNotRequired();
831 SetMinClusters((Int_t)(TMath::Abs(cuts[3])));
832 SetMinTracks((Int_t)(cuts[4]));
833 SetNSigmad0(cuts[5]);
834 SetMinDetFitter(cuts[6]);
836 SetFiducialRZ(cuts[8],cuts[9]);
837 fAlgo=(Int_t)(cuts[10]);
838 fAlgoIter0=(Int_t)(cuts[11]);
842 //---------------------------------------------------------------------------
843 void AliVertexerTracks::SetITSMode(Double_t dcacut,
844 Double_t dcacutIter0,
849 Double_t mindetfitter,
854 Int_t finderAlgoIter0)
857 // Cut values for ITS mode
861 SetITSrefitRequired();
863 SetITSrefitNotRequired();
866 SetDCAcutIter0(dcacutIter0);
868 SetMinClusters(TMath::Abs(minCls));
869 SetMinTracks(mintrks);
871 SetMinDetFitter(mindetfitter);
873 SetFiducialRZ(fidR,fidZ);
875 fAlgoIter0=finderAlgoIter0;
879 //---------------------------------------------------------------------------
880 void AliVertexerTracks::SetTPCMode(Double_t dcacut,
881 Double_t dcacutIter0,
886 Double_t mindetfitter,
891 Int_t finderAlgoIter0)
894 // Cut values for TPC mode
897 SetITSrefitNotRequired();
899 SetDCAcutIter0(dcacutIter0);
901 SetMinClusters(minCls);
902 SetMinTracks(mintrks);
904 SetMinDetFitter(mindetfitter);
906 SetFiducialRZ(fidR,fidZ);
908 fAlgoIter0=finderAlgoIter0;
912 //---------------------------------------------------------------------------
913 void AliVertexerTracks::SetSkipTracks(Int_t n,Int_t *skipped)
916 // Mark the tracks not to be used in the vertex reconstruction.
917 // Tracks are identified by AliESDtrack::GetID()
919 fNTrksToSkip = n; fTrksToSkip = new Int_t[n];
920 for(Int_t i=0;i<n;i++) fTrksToSkip[i] = skipped[i];
923 //---------------------------------------------------------------------------
924 void AliVertexerTracks::SetVtxStart(AliESDVertex *vtx)
927 // Set initial vertex knowledge
929 vtx->GetXYZ(fNominalPos);
930 vtx->GetCovMatrix(fNominalCov);
934 //---------------------------------------------------------------------------
935 void AliVertexerTracks::StrLinVertexFinderMinDist(Int_t optUseWeights)
937 AliExternalTrackParam *track1;
938 const Int_t knacc = (Int_t)fTrkArraySel.GetEntriesFast();
939 static TClonesArray linarray("AliStrLine",knacc);
940 for(Int_t i=0; i<knacc; i++){
941 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
942 Double_t alpha=track1->GetAlpha();
943 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
944 Double_t pos[3],dir[3],sigmasq[3];
945 track1->GetXYZAt(mindist,GetFieldkG(),pos);
946 track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
947 sigmasq[0]=TMath::Sin(alpha)*TMath::Sin(alpha)*track1->GetSigmaY2();
948 sigmasq[1]=TMath::Cos(alpha)*TMath::Cos(alpha)*track1->GetSigmaY2();
949 sigmasq[2]=track1->GetSigmaZ2();
952 //if(!TrackToPoint(track1,ri,wWi)) {printf("WARNING\n");continue;}
953 if(!TrackToPoint(track1,ri,wWi)) {optUseWeights=kFALSE;printf("WARNING\n");}
956 for(Int_t ia=0;ia<3;ia++){
957 for(Int_t ib=0;ib<3;ib++){
958 wmat[iel]=wWi(ia,ib);
962 new(linarray[i]) AliStrLine(pos,sigmasq,wmat,dir);
964 fVert=TrackletVertexFinder(&linarray,optUseWeights);
967 //---------------------------------------------------------------------------
968 AliESDVertex AliVertexerTracks::TrackletVertexFinder(TClonesArray *lines, Int_t optUseWeights)
970 // Calculate the point at minimum distance to prepared tracks
971 const Int_t knacc = (Int_t)lines->GetEntriesFast();
972 Double_t initPos[3]={0.,0.,0.};
974 Double_t (*vectP0)[3]=new Double_t [knacc][3];
975 Double_t (*vectP1)[3]=new Double_t [knacc][3];
978 Double_t dsum[3]={0,0,0};
980 for(Int_t i=0;i<3;i++){
981 for(Int_t j=0;j<3;j++){
987 for(Int_t i=0; i<knacc; i++){
988 AliStrLine* line1 = (AliStrLine*)lines->At(i);
989 Double_t p0[3],cd[3],sigmasq[3];
991 if(!line1) printf("ERROR %d %d\n",i,knacc);
994 line1->GetSigma2P0(sigmasq);
995 line1->GetWMatrix(wmat);
998 for(Int_t ia=0;ia<3;ia++){
999 for(Int_t ib=0;ib<3;ib++){
1000 wWi(ia,ib)=wmat[iel];
1007 Double_t p1[3]={p0[0]+cd[0],p0[1]+cd[1],p0[2]+cd[2]};
1015 Double_t matr[3][3];
1017 if(optUseWeights==0)GetStrLinDerivMatrix(p0,p1,matr,dknow);
1018 else GetStrLinDerivMatrix(p0,p1,sigmasq,matr,dknow);
1021 for(Int_t iii=0;iii<3;iii++){
1022 dsum[iii]+=dknow[iii];
1023 for(Int_t lj=0;lj<3;lj++) sum[iii][lj]+=matr[iii][lj];
1027 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
1028 Double_t covmatrix[6];
1029 covmatrix[0] = invsumWi(0,0);
1030 covmatrix[1] = invsumWi(0,1);
1031 covmatrix[2] = invsumWi(1,1);
1032 covmatrix[3] = invsumWi(0,2);
1033 covmatrix[4] = invsumWi(1,2);
1034 covmatrix[5] = invsumWi(2,2);
1036 Double_t vett[3][3];
1037 Double_t det=GetDeterminant3X3(sum);
1041 for(Int_t zz=0;zz<3;zz++){
1042 for(Int_t ww=0;ww<3;ww++){
1043 for(Int_t kk=0;kk<3;kk++) vett[ww][kk]=sum[ww][kk];
1045 for(Int_t kk=0;kk<3;kk++) vett[kk][zz]=dsum[kk];
1046 initPos[zz]=GetDeterminant3X3(vett)/det;
1050 for(Int_t i=0; i<knacc; i++){
1051 Double_t p0[3]={0,0,0},p1[3]={0,0,0};
1052 for(Int_t ii=0;ii<3;ii++){
1053 p0[ii]=vectP0[i][ii];
1054 p1[ii]=vectP1[i][ii];
1056 sigma+=GetStrLinMinDist(p0,p1,initPos);
1059 if(sigma>0.) {sigma=TMath::Sqrt(sigma);}else{sigma=999;}
1063 AliESDVertex theVert(initPos,covmatrix,99999.,knacc);
1064 theVert.SetDispersion(sigma);
1069 //---------------------------------------------------------------------------
1070 Bool_t AliVertexerTracks::TrackToPoint(AliExternalTrackParam *t,
1071 TMatrixD &ri,TMatrixD &wWi,
1072 Bool_t uUi3by3) const
1075 // Extract from the AliExternalTrackParam the global coordinates ri and covariance matrix
1076 // wWi of the space point that it represents (to be used in VertexFitter())
1080 Double_t rotAngle = t->GetAlpha();
1081 if(rotAngle<0.) rotAngle += 2.*TMath::Pi();
1082 Double_t cosRot = TMath::Cos(rotAngle);
1083 Double_t sinRot = TMath::Sin(rotAngle);
1085 ri(0,0) = t->GetX()*cosRot-t->GetY()*sinRot;
1086 ri(1,0) = t->GetX()*sinRot+t->GetY()*cosRot;
1087 ri(2,0) = t->GetZ();
1092 // matrix to go from global (x,y,z) to local (y,z);
1101 // covariance matrix of local (y,z) - inverted
1103 uUi(0,0) = t->GetSigmaY2();
1104 uUi(0,1) = t->GetSigmaZY();
1105 uUi(1,0) = t->GetSigmaZY();
1106 uUi(1,1) = t->GetSigmaZ2();
1108 //printf(" %f %f",uUi(0,0),uUi(0,1));
1109 //printf(" %f %f",uUi(1,0),uUi(1,1));
1111 if(uUi.Determinant() <= 0.) return kFALSE;
1112 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
1114 // weights matrix: wWi = qQiT * uUiInv * qQi
1115 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
1116 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
1119 if(fVert.GetNContributors()<1) AliFatal("Vertex from finder is empty");
1120 // matrix to go from global (x,y,z) to local (x,y,z);
1132 // covariance of fVert along the track
1133 Double_t p[3],pt,ptot;
1135 pt = TMath::Sqrt(p[0]*p[0]+p[1]*p[1]);
1136 ptot = TMath::Sqrt(pt*pt+p[2]*p[2]);
1137 Double_t cphi = p[0]/pt; //cos(phi)=px/pt
1138 Double_t sphi = p[1]/pt; //sin(phi)=py/pt
1139 Double_t clambda = pt/ptot; //cos(lambda)=pt/ptot
1140 Double_t slambda = p[2]/ptot; //sin(lambda)=pz/ptot
1141 Double_t covfVert[6];
1142 fVert.GetCovMatrix(covfVert);
1143 Double_t covfVertalongt =
1144 covfVert[0]*cphi*cphi*clambda*clambda
1145 +covfVert[1]*2.*cphi*sphi*clambda*clambda
1146 +covfVert[3]*2.*cphi*clambda*slambda
1147 +covfVert[2]*sphi*sphi*clambda*clambda
1148 +covfVert[4]*2.*sphi*clambda*slambda
1149 +covfVert[5]*slambda*slambda;
1150 // covariance matrix of local (x,y,z) - inverted
1152 uUi(0,0) = covfVertalongt * fnSigmaForUi00 * fnSigmaForUi00;
1153 AliDebug(1,Form("=====> sqrtUi00 cm %f",TMath::Sqrt(uUi(0,0))));
1157 uUi(1,1) = t->GetSigmaY2();
1158 uUi(1,2) = t->GetSigmaZY();
1160 uUi(2,1) = t->GetSigmaZY();
1161 uUi(2,2) = t->GetSigmaZ2();
1162 //printf(" Ui :\n");
1163 //printf(" %f %f\n",uUi(0,0),uUi(0,1));
1164 //printf(" %f %f\n",uUi(1,0),uUi(1,1));
1166 if(uUi.Determinant() <= 0.) return kFALSE;
1167 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
1169 // weights matrix: wWi = qQiT * uUiInv * qQi
1170 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
1171 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
1178 //---------------------------------------------------------------------------
1179 void AliVertexerTracks::TooFewTracks()
1182 // When the number of tracks is < fMinTracks,
1183 // deal with vertices not found and prepare to exit
1185 AliDebug(1,"TooFewTracks");
1187 Double_t pos[3],err[3];
1188 pos[0] = fNominalPos[0];
1189 err[0] = TMath::Sqrt(fNominalCov[0]);
1190 pos[1] = fNominalPos[1];
1191 err[1] = TMath::Sqrt(fNominalCov[2]);
1192 pos[2] = fNominalPos[2];
1193 err[2] = TMath::Sqrt(fNominalCov[5]);
1194 Int_t ncontr = (err[0]>1. ? -1 : -3);
1195 if(fCurrentVertex) { delete fCurrentVertex; fCurrentVertex=0; }
1196 fCurrentVertex = new AliESDVertex(pos,err);
1197 fCurrentVertex->SetNContributors(ncontr);
1200 fCurrentVertex->SetTitle("VertexerTracksWithConstraint");
1202 fCurrentVertex->SetTitle("VertexerTracksNoConstraint");
1205 if(!fTrkArraySel.IsEmpty()) fTrkArraySel.Delete();
1206 if(fIdSel) {delete [] fIdSel; fIdSel=NULL;}
1207 if(fTrksToSkip) {delete [] fTrksToSkip; fTrksToSkip=NULL;}
1211 //---------------------------------------------------------------------------
1212 void AliVertexerTracks::VertexFinder(Int_t optUseWeights)
1215 // Get estimate of vertex position in (x,y) from tracks DCA
1217 Double_t initPos[3];
1219 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
1220 Int_t nacc = (Int_t)fTrkArraySel.GetEntriesFast();
1221 Double_t aver[3]={0.,0.,0.};
1222 Double_t aversq[3]={0.,0.,0.};
1223 Double_t sigmasq[3]={0.,0.,0.};
1226 AliExternalTrackParam *track1;
1227 AliExternalTrackParam *track2;
1228 Double_t pos[3],dir[3];
1229 Double_t alpha,mindist;
1231 for(Int_t i=0; i<nacc; i++){
1232 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
1233 alpha=track1->GetAlpha();
1234 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1235 track1->GetXYZAt(mindist,GetFieldkG(),pos);
1236 track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
1237 AliStrLine *line1 = new AliStrLine(pos,dir);
1239 // AliStrLine *line1 = new AliStrLine();
1240 // track1->ApproximateHelixWithLine(mindist,GetFieldkG(),line1);
1242 for(Int_t j=i+1; j<nacc; j++){
1243 track2 = (AliExternalTrackParam*)fTrkArraySel.At(j);
1244 alpha=track2->GetAlpha();
1245 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1246 track2->GetXYZAt(mindist,GetFieldkG(),pos);
1247 track2->GetPxPyPzAt(mindist,GetFieldkG(),dir);
1248 AliStrLine *line2 = new AliStrLine(pos,dir);
1249 // AliStrLine *line2 = new AliStrLine();
1250 // track2->ApproximateHelixWithLine(mindist,GetFieldkG(),line2);
1251 Double_t distCA=line2->GetDCA(line1);
1252 //printf("%d %d %f\n",i,j,distCA);
1253 if(fDCAcut<=0 || (fDCAcut>0&&distCA<fDCAcut)){
1254 Double_t pnt1[3],pnt2[3],crosspoint[3];
1256 if(optUseWeights<=0){
1257 Int_t retcode = line2->Cross(line1,crosspoint);
1260 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
1261 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1264 if(optUseWeights>0){
1265 Int_t retcode = line1->CrossPoints(line2,pnt1,pnt2);
1268 alpha=track1->GetAlpha();
1269 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
1270 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
1271 alpha=track2->GetAlpha();
1272 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
1273 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
1274 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
1275 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
1276 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
1277 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
1278 crosspoint[0]=wx1*pnt1[0] + wx2*pnt2[0];
1279 crosspoint[1]=wy1*pnt1[1] + wy2*pnt2[1];
1280 crosspoint[2]=wz1*pnt1[2] + wz2*pnt2[2];
1283 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
1284 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1293 for(Int_t jj=0;jj<3;jj++){
1294 initPos[jj] = aver[jj]/ncombi;
1295 //printf("%f\n",initPos[jj]);
1297 sigmasq[jj]=aversq[jj]-initPos[jj]*initPos[jj];
1300 sigma=TMath::Sqrt(TMath::Abs(sigma));
1303 Warning("VertexFinder","Finder did not succed");
1306 fVert.SetXYZ(initPos);
1307 fVert.SetDispersion(sigma);
1308 fVert.SetNContributors(ncombi);
1310 //---------------------------------------------------------------------------
1311 void AliVertexerTracks::VertexFitter()
1314 // The optimal estimate of the vertex position is given by a "weighted
1315 // average of tracks positions".
1316 // Original method: V. Karimaki, CMS Note 97/0051
1318 Bool_t useConstraint = fConstraint;
1319 Double_t initPos[3];
1321 fVert.GetXYZ(initPos);
1323 initPos[0]=fNominalPos[0];
1324 initPos[1]=fNominalPos[1];
1325 initPos[2]=fNominalPos[2];
1328 Int_t nTrksSel = (Int_t)fTrkArraySel.GetEntries();
1329 if(nTrksSel==1) useConstraint=kTRUE;
1330 AliDebug(1,"--- VertexFitter(): start");
1331 AliDebug(1,Form(" Number of tracks in array: %d\n",nTrksSel));
1332 AliDebug(1,Form(" Minimum # tracks required in fit: %d\n",fMinTracks));
1333 AliDebug(1,Form(" Vertex position after finder: %f,%f,%f\n",initPos[0],initPos[1],initPos[2]));
1334 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])));
1336 // special treatment for few-tracks fits (e.g. secondary vertices)
1337 Bool_t uUi3by3 = kFALSE; if(nTrksSel<5 && !useConstraint) uUi3by3 = kTRUE;
1342 rv(0,0) = initPos[0];
1343 rv(1,0) = initPos[1];
1345 Double_t xlStart,alpha;
1347 Double_t chi2,chi2i,chi2b;
1348 AliExternalTrackParam *t = 0;
1351 // initial vertex covariance matrix
1353 vVb(0,0) = fNominalCov[0];
1354 vVb(0,1) = fNominalCov[1];
1356 vVb(1,0) = fNominalCov[1];
1357 vVb(1,1) = fNominalCov[2];
1361 vVb(2,2) = fNominalCov[5];
1362 TMatrixD vVbInv(TMatrixD::kInverted,vVb);
1364 rb(0,0) = fNominalPos[0];
1365 rb(1,0) = fNominalPos[1];
1366 rb(2,0) = fNominalPos[2];
1367 TMatrixD vVbInvrb(vVbInv,TMatrixD::kMult,rb);
1371 // 1st - estimate of vtx using all tracks
1372 // 2nd - estimate of global chi2
1373 for(step=0; step<2; step++) {
1374 AliDebug(1,Form(" step = %d\n",step));
1378 if(step==1) { initPos[0]=rv(0,0); initPos[0]=rv(1,0); }
1380 TMatrixD sumWiri(3,1);
1381 TMatrixD sumWi(3,3);
1382 for(i=0; i<3; i++) {
1384 for(j=0; j<3; j++) sumWi(j,i) = 0.;
1387 // mean vertex constraint
1390 sumWiri(i,0) += vVbInvrb(i,0);
1391 for(k=0;k<3;k++) sumWi(i,k) += vVbInv(i,k);
1394 TMatrixD deltar = rv; deltar -= rb;
1395 TMatrixD vVbInvdeltar(vVbInv,TMatrixD::kMult,deltar);
1396 chi2b = deltar(0,0)*vVbInvdeltar(0,0)+
1397 deltar(1,0)*vVbInvdeltar(1,0)+
1398 deltar(2,0)*vVbInvdeltar(2,0);
1403 for(k=0; k<nTrksSel; k++) {
1404 // get track from track array
1405 t = (AliExternalTrackParam*)fTrkArraySel.At(k);
1406 alpha = t->GetAlpha();
1407 xlStart = initPos[0]*TMath::Cos(alpha)+initPos[1]*TMath::Sin(alpha);
1408 // to vtxSeed (from finder)
1409 t->PropagateTo(xlStart,GetFieldkG());
1411 // vector of track global coordinates
1413 // covariance matrix of ri
1416 // get space point from track
1417 if(!TrackToPoint(t,ri,wWi,uUi3by3)) continue;
1418 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
1421 TMatrixD deltar = rv; deltar -= ri;
1422 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
1423 chi2i = deltar(0,0)*wWideltar(0,0)+
1424 deltar(1,0)*wWideltar(1,0)+
1425 deltar(2,0)*wWideltar(2,0);
1427 // add to total chi2
1434 } // end loop on tracks
1436 if(nTrksUsed < fMinTracks) {
1441 Double_t determinant = sumWi.Determinant();
1442 if(determinant < fMinDetFitter) {
1443 AliDebug(1,Form("det(V) = %f (<%f)\n",determinant,fMinDetFitter));
1449 // inverted of weights matrix
1450 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
1452 // position of primary vertex
1453 rv.Mult(vV,sumWiri);
1455 } // end loop on the 2 steps
1462 Double_t position[3];
1463 position[0] = rv(0,0);
1464 position[1] = rv(1,0);
1465 position[2] = rv(2,0);
1466 Double_t covmatrix[6];
1467 covmatrix[0] = vV(0,0);
1468 covmatrix[1] = vV(0,1);
1469 covmatrix[2] = vV(1,1);
1470 covmatrix[3] = vV(0,2);
1471 covmatrix[4] = vV(1,2);
1472 covmatrix[5] = vV(2,2);
1474 // for correct chi2/ndf, count constraint as additional "track"
1475 if(fConstraint) nTrksUsed++;
1476 // store data in the vertex object
1477 if(fCurrentVertex) { delete fCurrentVertex; fCurrentVertex=0; }
1478 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nTrksUsed);
1480 AliDebug(1," Vertex after fit:");
1481 AliDebug(1,Form("xyz: %f %f %f; nc %d",fCurrentVertex->GetXv(),fCurrentVertex->GetYv(),fCurrentVertex->GetZv(),fCurrentVertex->GetNContributors()));
1482 AliDebug(1,"--- VertexFitter(): finish\n");
1487 //----------------------------------------------------------------------------
1488 AliESDVertex* AliVertexerTracks::VertexForSelectedTracks(TObjArray *trkArray,
1490 Bool_t optUseFitter,
1491 Bool_t optPropagate)
1494 // Return vertex from tracks (AliExternalTrackParam) in array
1499 // get tracks and propagate them to initial vertex position
1500 fIdSel = new UShort_t[(Int_t)trkArray->GetEntriesFast()];
1501 Int_t nTrksSel = PrepareTracks(*trkArray,id,0);
1502 if(nTrksSel < TMath::Max(2,fMinTracks)) {
1504 return fCurrentVertex;
1509 case 1: StrLinVertexFinderMinDist(1); break;
1510 case 2: StrLinVertexFinderMinDist(0); break;
1511 case 3: HelixVertexFinder(); break;
1512 case 4: VertexFinder(1); break;
1513 case 5: VertexFinder(0); break;
1514 default: printf("Wrong algorithm\n"); break;
1516 AliDebug(1," Vertex finding completed\n");
1522 Double_t position[3]={fVert.GetXv(),fVert.GetYv(),fVert.GetZv()};
1523 Double_t covmatrix[6];
1524 fVert.GetCovMatrix(covmatrix);
1525 Double_t chi2=99999.;
1526 Int_t nTrksUsed=fVert.GetNContributors();
1527 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nTrksUsed);
1529 fCurrentVertex->SetDispersion(fVert.GetDispersion());
1532 // set indices of used tracks and propagate track to found vertex
1533 UShort_t *indices = 0;
1534 Double_t d0z0[2],covd0z0[3];
1535 AliExternalTrackParam *t = 0;
1536 if(fCurrentVertex->GetNContributors()>0) {
1537 indices = new UShort_t[fCurrentVertex->GetNContributors()];
1538 for(Int_t jj=0; jj<(Int_t)fTrkArraySel.GetEntriesFast(); jj++) {
1539 indices[jj] = fIdSel[jj];
1540 t = (AliExternalTrackParam*)fTrkArraySel.At(jj);
1541 if(optPropagate && optUseFitter) {
1542 if(TMath::Sqrt(fCurrentVertex->GetXv()*fCurrentVertex->GetXv()+fCurrentVertex->GetYv()*fCurrentVertex->GetYv())<3.) {
1543 t->PropagateToDCA(fCurrentVertex,GetFieldkG(),100.,d0z0,covd0z0);
1544 AliDebug(1,Form("Track %d propagated to found vertex",jj));
1546 AliWarning("Found vertex outside beam pipe!");
1550 fCurrentVertex->SetIndices(fCurrentVertex->GetNContributors(),indices);
1554 delete [] indices; indices=NULL;
1555 delete [] fIdSel; fIdSel=NULL;
1556 fTrkArraySel.Delete();
1558 return fCurrentVertex;
1560 //----------------------------------------------------------------------------
1561 AliESDVertex* AliVertexerTracks::VertexForSelectedESDTracks(TObjArray *trkArray,
1562 Bool_t optUseFitter,
1563 Bool_t optPropagate)
1566 // Return vertex from array of ESD tracks
1569 Int_t nTrks = (Int_t)trkArray->GetEntriesFast();
1570 UShort_t *id = new UShort_t[nTrks];
1572 AliESDtrack *esdt = 0;
1573 for(Int_t i=0; i<nTrks; i++){
1574 esdt = (AliESDtrack*)trkArray->At(i);
1575 id[i] = (UShort_t)esdt->GetID();
1578 VertexForSelectedTracks(trkArray,id,optUseFitter,optPropagate);
1580 delete [] id; id=NULL;
1582 return fCurrentVertex;
1584 //--------------------------------------------------------------------------