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 -----
35 #include "AliStrLine.h"
36 #include "AliExternalTrackParam.h"
37 #include "AliESDEvent.h"
38 #include "AliESDtrack.h"
39 #include "AliVertexerTracks.h"
41 ClassImp(AliVertexerTracks)
44 //----------------------------------------------------------------------------
45 AliVertexerTracks::AliVertexerTracks():
71 // Default constructor
77 //----------------------------------------------------------------------------
78 AliVertexerTracks::AliVertexerTracks(Double_t fieldkG):
104 // Standard constructor
110 //-----------------------------------------------------------------------------
111 AliVertexerTracks::~AliVertexerTracks()
113 // Default Destructor
114 // The objects pointed by the following pointer are not owned
115 // by this class and are not deleted
117 if(fTrksToSkip) { delete [] fTrksToSkip; fTrksToSkip=NULL; }
118 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
120 //----------------------------------------------------------------------------
121 AliESDVertex* AliVertexerTracks::FindPrimaryVertex(const AliESDEvent *esdEvent)
124 // Primary vertex for current ESD event
126 // 1st with 5*fNSigma*sigma cut w.r.t. to initial vertex
127 // + cut on sqrt(d0d0+z0z0) if fConstraint=kFALSE
128 // 2nd with fNSigma*sigma cut w.r.t. to vertex found in 1st iteration)
132 // accept 1-track case only if constraint is available
133 if(!fConstraint && fMinTracks==1) fMinTracks=2;
135 // read tracks from ESD
136 Int_t nTrks = (Int_t)esdEvent->GetNumberOfTracks();
137 if(nTrks<fMinTracks) {
139 return fCurrentVertex;
143 TDirectory * olddir = gDirectory;
145 if(nTrks>500) f = new TFile("VertexerTracks.root","recreate");
146 TObjArray trkArrayOrig(nTrks);
147 UShort_t *idOrig = new UShort_t[nTrks];
150 AliExternalTrackParam *t=0;
151 // loop on ESD tracks
152 for(Int_t i=0; i<nTrks; i++) {
153 AliESDtrack *esdt = esdEvent->GetTrack(i);
154 // check tracks to skip
155 Bool_t skipThis = kFALSE;
156 for(Int_t j=0; j<fNTrksToSkip; j++) {
157 if(esdt->GetID()==fTrksToSkip[j]) {
158 if(fDebug) printf("skipping track: %d\n",i);
162 if(skipThis) continue;
164 if(fMode==0) { // ITS mode
165 if(fITSrefit && !(esdt->GetStatus()&AliESDtrack::kITSrefit)) continue;
166 // check number of clusters in ITS
167 if(esdt->GetNcls(0)<fMinITSClusters) continue;
168 Double_t x,p[5],cov[15];
169 esdt->GetExternalParameters(x,p);
170 esdt->GetExternalCovariance(cov);
171 t = new AliExternalTrackParam(x,esdt->GetAlpha(),p,cov);
172 } else if(fMode==1) { // TPC mode
173 t = (AliExternalTrackParam*)esdt->GetTPCInnerParam();
175 Double_t radius = 2.8; //something less than the beam pipe radius
176 if(!PropagateTrackTo(t,radius)) continue;
178 trkArrayOrig.AddLast(t);
179 idOrig[nTrksOrig]=(UShort_t)esdt->GetID();
181 } // end loop on ESD tracks
183 // call method that will reconstruct the vertex
184 FindPrimaryVertex(&trkArrayOrig,idOrig);
186 if(fMode==0) trkArrayOrig.Delete();
187 delete [] idOrig; idOrig=NULL;
190 f->Close(); delete f; f = NULL;
191 gSystem->Unlink("VertexerTracks.root");
195 return fCurrentVertex;
197 //----------------------------------------------------------------------------
198 AliESDVertex* AliVertexerTracks::FindPrimaryVertex(TObjArray *trkArrayOrig,
202 // Primary vertex using the AliExternalTrackParam's in the TObjArray.
203 // idOrig must contain the track IDs from AliESDtrack::GetID()
205 // 1st with 5*fNSigma*sigma cut w.r.t. to initial vertex
206 // + cut on sqrt(d0d0+z0z0) if fConstraint=kFALSE
207 // 2nd with fNSigma*sigma cut w.r.t. to vertex found in 1st iteration)
211 // accept 1-track case only if constraint is available
212 if(!fConstraint && fMinTracks==1) fMinTracks=2;
214 // read tracks from array
215 Int_t nTrksOrig = (Int_t)trkArrayOrig->GetEntriesFast();
216 if(fDebug) printf("Initial number of tracks: %d\n",nTrksOrig);
217 if(nTrksOrig<fMinTracks) {
218 if(fDebug) printf("TooFewTracks\n");
220 return fCurrentVertex;
223 // If fConstraint=kFALSE
224 // run VertexFinder(1) to get rough estimate of initVertex (x,y)
226 // fill fTrkArraySel, for VertexFinder()
227 fIdSel = new UShort_t[nTrksOrig];
228 PrepareTracks(*trkArrayOrig,idOrig,0);
229 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
230 Double_t cutsave = fDCAcut;
231 fDCAcut = fDCAcutIter0;
232 VertexFinder(1); // using weights, cutting dca < fDCAcutIter0
234 if(fVert.GetNContributors()>0) {
235 fVert.GetXYZ(fNominalPos);
236 fNominalPos[0] = fVert.GetXv();
237 fNominalPos[1] = fVert.GetYv();
238 fNominalPos[2] = fVert.GetZv();
239 if(fDebug) printf("No mean vertex: VertexFinder gives (%f, %f, %f)\n",fNominalPos[0],fNominalPos[1],fNominalPos[2]);
244 if(fDebug) printf("No mean vertex and VertexFinder failed\n");
251 // propagate tracks to fNominalPos vertex
253 // if(constraint) reject for |d0|>5*fNSigma*sigma w.r.t. fNominal... vertex
254 // else reject for |d0|\oplus|z0| > 5 mm w.r.t. fNominal... vertex
256 // propagate tracks to best between initVertex and fCurrentVertex
257 // preselect tracks (reject for |d0|>fNSigma*sigma w.r.t. best
258 // between initVertex and fCurrentVertex)
259 for(Int_t iter=1; iter<=2; iter++) {
260 if(fOnlyFitter && iter==1) continue;
261 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
262 fIdSel = new UShort_t[nTrksOrig];
263 Int_t nTrksSel = PrepareTracks(*trkArrayOrig,idOrig,iter);
264 if(fDebug) printf("N tracks selected in iteration %d: %d\n",iter,nTrksSel);
265 if(nTrksSel < fMinTracks) {
267 return fCurrentVertex;
273 if(fDebug) printf("Just one track\n");
274 OneTrackVertFinder();
277 case 1: StrLinVertexFinderMinDist(1); break;
278 case 2: StrLinVertexFinderMinDist(0); break;
279 case 3: HelixVertexFinder(); break;
280 case 4: VertexFinder(1); break;
281 case 5: VertexFinder(0); break;
282 default: printf("Wrong algorithm\n"); break;
285 if(fDebug) printf(" Vertex finding completed\n");
290 } // end loop on the two iterations
293 // set indices of used tracks
294 UShort_t *indices = 0;
295 if(fCurrentVertex->GetNContributors()>0) {
296 Int_t nIndices = (Int_t)fTrkArraySel.GetEntriesFast();
297 indices = new UShort_t[nIndices];
298 for(Int_t jj=0; jj<nIndices; jj++)
299 indices[jj] = fIdSel[jj];
300 fCurrentVertex->SetIndices(nIndices,indices);
302 delete [] indices; indices=NULL;
306 TString title="VertexerTracksNoConstraint";
308 title="VertexerTracksWithConstraint";
309 if(fOnlyFitter) title.Append("OnlyFitter");
311 fCurrentVertex->SetTitle(title.Data());
315 fCurrentVertex->PrintStatus();
316 fCurrentVertex->PrintIndices();
320 delete [] fIdSel; fIdSel=NULL;
321 fTrkArraySel.Delete();
322 if(fTrksToSkip) { delete [] fTrksToSkip; fTrksToSkip=NULL; }
325 return fCurrentVertex;
327 //------------------------------------------------------------------------
328 Double_t AliVertexerTracks::GetDeterminant3X3(Double_t matr[][3])
331 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];
334 //-------------------------------------------------------------------------
335 void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t (*m)[3],Double_t *d)
338 Double_t x12=p0[0]-p1[0];
339 Double_t y12=p0[1]-p1[1];
340 Double_t z12=p0[2]-p1[2];
341 Double_t kk=x12*x12+y12*y12+z12*z12;
342 m[0][0]=2-2/kk*x12*x12;
343 m[0][1]=-2/kk*x12*y12;
344 m[0][2]=-2/kk*x12*z12;
345 m[1][0]=-2/kk*x12*y12;
346 m[1][1]=2-2/kk*y12*y12;
347 m[1][2]=-2/kk*y12*z12;
348 m[2][0]=-2/kk*x12*z12;
350 m[2][2]=2-2/kk*z12*z12;
351 d[0]=2*p0[0]-2/kk*p0[0]*x12*x12-2/kk*p0[2]*x12*z12-2/kk*p0[1]*x12*y12;
352 d[1]=2*p0[1]-2/kk*p0[1]*y12*y12-2/kk*p0[0]*x12*y12-2/kk*p0[2]*z12*y12;
353 d[2]=2*p0[2]-2/kk*p0[2]*z12*z12-2/kk*p0[0]*x12*z12-2/kk*p0[1]*z12*y12;
356 //--------------------------------------------------------------------------
357 void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t *sigmasq,Double_t (*m)[3],Double_t *d)
360 Double_t x12=p1[0]-p0[0];
361 Double_t y12=p1[1]-p0[1];
362 Double_t z12=p1[2]-p0[2];
364 Double_t den= x12*x12*sigmasq[1]*sigmasq[2]+y12*y12*sigmasq[0]*sigmasq[2]+z12*z12*sigmasq[0]*sigmasq[1];
366 Double_t kk= 2*(x12*x12/sigmasq[0]+y12*y12/sigmasq[1]+z12*z12/sigmasq[2]);
369 cc[0]=-x12/sigmasq[0];
370 cc[1]=-y12/sigmasq[1];
371 cc[2]=-z12/sigmasq[2];
373 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;
375 Double_t ss= -p0[0]*cc[0]-p0[1]*cc[1]-p0[2]*cc[2];
378 aa[0]=x12*sigmasq[1]*sigmasq[2]/den;
379 aa[1]=y12*sigmasq[0]*sigmasq[2]/den;
380 aa[2]=z12*sigmasq[0]*sigmasq[1]/den;
382 m[0][0]=aa[0]*(aa[0]*kk+2*cc[0])+2*cc[0]*aa[0]+2/sigmasq[0];
383 m[0][1]=aa[1]*(aa[0]*kk+2*cc[0])+2*cc[1]*aa[0];
384 m[0][2]=aa[2]*(aa[0]*kk+2*cc[0])+2*cc[2]*aa[0];
386 m[1][0]=aa[0]*(aa[1]*kk+2*cc[1])+2*cc[0]*aa[1];
387 m[1][1]=aa[1]*(aa[1]*kk+2*cc[1])+2*cc[1]*aa[1]+2/sigmasq[1];
388 m[1][2]=aa[2]*(aa[1]*kk+2*cc[1])+2*cc[2]*aa[1];
390 m[2][0]=aa[0]*(aa[2]*kk+2*cc[2])+2*cc[0]*aa[2];
391 m[2][1]=aa[1]*(aa[2]*kk+2*cc[2])+2*cc[1]*aa[2];
392 m[2][2]=aa[2]*(aa[2]*kk+2*cc[2])+2*cc[2]*aa[2]+2/sigmasq[2];
394 d[0]=-ww*(aa[0]*kk+2*cc[0])-2*ss*aa[0]+2*p0[0]/sigmasq[0];
395 d[1]=-ww*(aa[1]*kk+2*cc[1])-2*ss*aa[1]+2*p0[1]/sigmasq[1];
396 d[2]=-ww*(aa[2]*kk+2*cc[2])-2*ss*aa[2]+2*p0[2]/sigmasq[2];
399 //--------------------------------------------------------------------------
400 Double_t AliVertexerTracks::GetStrLinMinDist(Double_t *p0,Double_t *p1,Double_t *x0)
403 Double_t x12=p0[0]-p1[0];
404 Double_t y12=p0[1]-p1[1];
405 Double_t z12=p0[2]-p1[2];
406 Double_t x10=p0[0]-x0[0];
407 Double_t y10=p0[1]-x0[1];
408 Double_t z10=p0[2]-x0[2];
409 // 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);
410 return ((y10*z12-z10*y12)*(y10*z12-z10*y12)+
411 (z10*x12-x10*z12)*(z10*x12-x10*z12)+
412 (x10*y12-y10*x12)*(x10*y12-y10*x12))
413 /(x12*x12+y12*y12+z12*z12);
415 //---------------------------------------------------------------------------
416 void AliVertexerTracks::OneTrackVertFinder()
418 // find vertex for events with 1 track, using DCA to nominal beam axis
419 if(fDebug) printf("Number of prepared tracks =%d - Call OneTrackVertFinder",fTrkArraySel.GetEntries());
420 AliExternalTrackParam *track1;
421 track1 = (AliExternalTrackParam*)fTrkArraySel.At(0);
422 Double_t alpha=track1->GetAlpha();
423 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
424 Double_t pos[3],dir[3];
425 track1->GetXYZAt(mindist,GetFieldkG(),pos);
426 track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
427 AliStrLine *line1 = new AliStrLine(pos,dir);
428 Double_t p1[3]={fNominalPos[0],fNominalPos[1],0.};
429 Double_t p2[3]={fNominalPos[0],fNominalPos[1],10.};
430 AliStrLine *zeta=new AliStrLine(p1,p2,kTRUE);
431 Double_t crosspoint[3]={0.,0.,0.};
434 Int_t retcode = zeta->Cross(line1,crosspoint);
436 sigma=line1->GetDistFromPoint(crosspoint);
441 fVert.SetXYZ(crosspoint);
442 fVert.SetDispersion(sigma);
443 fVert.SetNContributors(nContrib);
445 //---------------------------------------------------------------------------
446 void AliVertexerTracks::HelixVertexFinder()
448 // Get estimate of vertex position in (x,y) from tracks DCA
453 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
455 Int_t nacc = (Int_t)fTrkArraySel.GetEntriesFast();
457 Double_t aver[3]={0.,0.,0.};
458 Double_t averquad[3]={0.,0.,0.};
459 Double_t sigmaquad[3]={0.,0.,0.};
462 AliExternalTrackParam *track1;
463 AliExternalTrackParam *track2;
466 Double_t alpha, cs, sn;
467 Double_t crosspoint[3];
468 for(Int_t i=0; i<nacc; i++){
469 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
472 for(Int_t j=i+1; j<nacc; j++){
473 track2 = (AliExternalTrackParam*)fTrkArraySel.At(j);
475 distCA=track2->PropagateToDCA(track1,GetFieldkG());
476 if(fDCAcut<=0 ||(fDCAcut>0&&distCA<fDCAcut)){
478 alpha=track1->GetAlpha();
479 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
480 Double_t x1=x*cs - track1->GetY()*sn;
481 Double_t y1=x*sn + track1->GetY()*cs;
482 Double_t z1=track1->GetZ();
484 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
486 alpha=track2->GetAlpha();
487 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
488 Double_t x2=x*cs - track2->GetY()*sn;
489 Double_t y2=x*sn + track2->GetY()*cs;
490 Double_t z2=track2->GetZ();
491 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
492 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
493 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
494 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
495 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
496 crosspoint[0]=wx1*x1 + wx2*x2;
497 crosspoint[1]=wy1*y1 + wy2*y2;
498 crosspoint[2]=wz1*z1 + wz2*z2;
501 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
502 for(Int_t jj=0;jj<3;jj++)averquad[jj]+=(crosspoint[jj]*crosspoint[jj]);
508 for(Int_t jj=0;jj<3;jj++){
509 initPos[jj] = aver[jj]/ncombi;
510 averquad[jj]/=ncombi;
511 sigmaquad[jj]=averquad[jj]-initPos[jj]*initPos[jj];
512 sigma+=sigmaquad[jj];
514 sigma=TMath::Sqrt(TMath::Abs(sigma));
517 Warning("HelixVertexFinder","Finder did not succed");
520 fVert.SetXYZ(initPos);
521 fVert.SetDispersion(sigma);
522 fVert.SetNContributors(ncombi);
524 //----------------------------------------------------------------------------
525 Int_t AliVertexerTracks::PrepareTracks(TObjArray &trkArrayOrig,
530 // Propagate tracks to initial vertex position and store them in a TObjArray
532 if(fDebug) printf(" PrepareTracks()\n");
534 Int_t nTrksOrig = (Int_t)trkArrayOrig.GetEntriesFast();
537 Double_t fiducialR = 3.0, fiducialZ = 20.0; // pipe and 1.5xSPD
538 Double_t sigmaCurr[3];
539 Double_t normdistx,normdisty;
540 Double_t d0z0[2],covd0z0[3];
543 AliESDVertex *initVertex = new AliESDVertex(fNominalPos,fNominalCov,1,1);
545 if(!fTrkArraySel.IsEmpty()) fTrkArraySel.Delete();
547 AliExternalTrackParam *track=0;
550 for(Int_t i=0; i<nTrksOrig; i++) {
551 track = new AliExternalTrackParam(*(AliExternalTrackParam*)trkArrayOrig.At(i));
553 if(TMath::Abs(track->GetTgl())>fMaxTgl) {
554 if(fDebug) printf(" rejecting track with tgl = %f\n",track->GetTgl());
555 delete track; continue;
558 // propagate track to vertex
559 if(optImpParCut<2 || fOnlyFitter) { // optImpParCut==1 or 0
560 track->PropagateToDCA(initVertex,GetFieldkG(),100.,d0z0,covd0z0);
561 } else { // optImpParCut==2
562 fCurrentVertex->GetSigmaXYZ(sigmaCurr);
563 normdistx = TMath::Abs(fCurrentVertex->GetXv()-fNominalPos[0])/TMath::Sqrt(sigmaCurr[0]*sigmaCurr[0]+fNominalCov[0]);
564 normdisty = TMath::Abs(fCurrentVertex->GetYv()-fNominalPos[1])/TMath::Sqrt(sigmaCurr[1]*sigmaCurr[1]+fNominalCov[2]);
565 if(normdistx < 3. && normdisty < 3. &&
566 (sigmaCurr[0]+sigmaCurr[1])<(TMath::Sqrt(fNominalCov[0])+TMath::Sqrt(fNominalCov[2]))) {
567 track->PropagateToDCA(fCurrentVertex,GetFieldkG(),100.,d0z0,covd0z0);
569 track->PropagateToDCA(initVertex,GetFieldkG(),100.,d0z0,covd0z0);
573 sigmad0 = TMath::Sqrt(covd0z0[0]);
574 maxd0rphi = fNSigma*sigmad0;
575 if(optImpParCut==1) maxd0rphi *= 5.;
576 maxd0rphi = TMath::Min(maxd0rphi,fiducialR);
577 //sigmad0z0 = TMath::Sqrt(covd0z0[0]+covd0z0[2]); // for future improvement
578 //maxd0z0 = 10.*fNSigma*sigmad0z0;
580 if(fDebug) printf("trk %d; id %d; |d0| = %f; d0 cut = %f; |z0| = %f; |d0|oplus|z0| = %f; d0z0 cut = %f\n",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);
583 //---- track selection based on impact parameters ----//
585 // always reject tracks outside fiducial volume
586 if(TMath::Abs(d0z0[0])>fiducialR || TMath::Abs(d0z0[1])>fiducialZ) {
587 if(fDebug) printf(" rejected\n");
588 delete track; continue;
591 // during iterations 1 and 2 , reject tracks with d0rphi > maxd0rphi
592 if(optImpParCut>0 && TMath::Abs(d0z0[0])>maxd0rphi) {
593 if(fDebug) printf(" rejected\n");
594 delete track; continue;
597 // if fConstraint=kFALSE, during iterations 1 and 2 ||
598 // if fConstraint=kTRUE, during iteration 2,
599 // select tracks with d0oplusz0 < fMaxd0z0
600 if((!fConstraint && optImpParCut>0 && fVert.GetNContributors()>0) ||
601 ( fConstraint && optImpParCut==2)) {
603 TMath::Sqrt(d0z0[0]*d0z0[0]+d0z0[1]*d0z0[1])>fMaxd0z0) {
604 if(fDebug) printf(" rejected\n");
605 delete track; continue;
609 // track passed all selections
610 fTrkArraySel.AddLast(track);
611 fIdSel[nTrksSel] = idOrig[i];
613 } // end loop on tracks
619 //----------------------------------------------------------------------------
620 Bool_t AliVertexerTracks::PropagateTrackTo(AliExternalTrackParam *track,
622 //----------------------------------------------------------------
623 // COPIED from AliTracker
625 // Propagates the track to the plane X=xk (cm).
627 // Origin: Marian Ivanov, Marian.Ivanov@cern.ch
628 //----------------------------------------------------------------
630 const Double_t kEpsilon = 0.00001;
631 Double_t xpos = track->GetX();
632 Double_t dir = (xpos<xToGo) ? 1. : -1.;
633 Double_t maxStep = 5;
634 Double_t maxSnp = 0.8;
636 while ( (xToGo-xpos)*dir > kEpsilon){
637 Double_t step = dir*TMath::Min(TMath::Abs(xToGo-xpos), maxStep);
638 Double_t x = xpos+step;
639 Double_t xyz0[3],xyz1[3];
640 track->GetXYZ(xyz0); //starting global position
642 if(!track->GetXYZAt(x,GetFieldkG(),xyz1)) return kFALSE; // no prolongation
643 xyz1[2]+=kEpsilon; // waiting for bug correction in geo
645 if(TMath::Abs(track->GetSnpAt(x,GetFieldkG())) >= maxSnp) return kFALSE;
646 if(!track->PropagateTo(x,GetFieldkG())) return kFALSE;
648 if(TMath::Abs(track->GetSnp()) >= maxSnp) return kFALSE;
649 track->GetXYZ(xyz0); // global position
650 Double_t alphan = TMath::ATan2(xyz0[1], xyz0[0]);
652 Double_t ca=TMath::Cos(alphan-track->GetAlpha()),
653 sa=TMath::Sin(alphan-track->GetAlpha());
654 Double_t sf=track->GetSnp(), cf=TMath::Sqrt(1.- sf*sf);
655 Double_t sinNew = sf*ca - cf*sa;
656 if(TMath::Abs(sinNew) >= maxSnp) return kFALSE;
657 if(!track->Rotate(alphan)) return kFALSE;
659 xpos = track->GetX();
663 //---------------------------------------------------------------------------
664 AliESDVertex* AliVertexerTracks::RemoveTracksFromVertex(AliESDVertex *inVtx,
670 // Removes tracks in trksTree from fit of inVtx
673 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraint")) {
674 printf("ERROR: primary vertex has no constraint: cannot remove tracks\n");
677 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraintOnlyFitter"))
678 printf("WARNING: result of tracks' removal will be only approximately correct\n");
681 rv(0,0) = inVtx->GetXv();
682 rv(1,0) = inVtx->GetYv();
683 rv(2,0) = inVtx->GetZv();
686 inVtx->GetCovMatrix(cov);
688 vV(0,1) = cov[1]; vV(1,0) = cov[1];
690 vV(0,2) = cov[3]; vV(2,0) = cov[3];
691 vV(1,2) = cov[4]; vV(2,1) = cov[4];
694 TMatrixD sumWi(TMatrixD::kInverted,vV);
695 TMatrixD sumWiri(sumWi,TMatrixD::kMult,rv);
697 Int_t nUsedTrks = inVtx->GetNIndices();
698 Double_t chi2 = inVtx->GetChi2();
700 AliExternalTrackParam *track = 0;
701 Int_t ntrks = (Int_t)trkArray->GetEntriesFast();
702 for(Int_t i=0;i<ntrks;i++) {
703 track = (AliExternalTrackParam*)trkArray->At(i);
704 if(!inVtx->UsesTrack(id[i])) {
705 printf("track %d was not used in vertex fit\n",id[i]);
708 Double_t alpha = track->GetAlpha();
709 Double_t xl = diamondxy[0]*TMath::Cos(alpha)+diamondxy[1]*TMath::Sin(alpha);
710 track->PropagateTo(xl,GetFieldkG());
711 // vector of track global coordinates
713 // covariance matrix of ri
716 // get space point from track
717 if(!TrackToPoint(track,ri,wWi)) continue;
719 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
725 TMatrixD deltar = rv; deltar -= ri;
726 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
727 Double_t chi2i = deltar(0,0)*wWideltar(0,0)+
728 deltar(1,0)*wWideltar(1,0)+
729 deltar(2,0)*wWideltar(2,0);
730 // remove from total chi2
735 printf("Trying to remove too many tracks!\n");
743 // new inverted of weights matrix
744 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
746 // new position of primary vertex
747 rvnew.Mult(vVnew,sumWiri);
749 Double_t position[3];
750 position[0] = rvnew(0,0);
751 position[1] = rvnew(1,0);
752 position[2] = rvnew(2,0);
760 // store data in the vertex object
761 AliESDVertex *outVtx = new AliESDVertex(position,cov,chi2,nUsedTrks);
762 outVtx->SetTitle(inVtx->GetTitle());
763 UShort_t *inindices = inVtx->GetIndices();
764 Int_t nIndices = nUsedTrks;
765 UShort_t *outindices = new UShort_t[nIndices];
767 for(Int_t k=0; k<inVtx->GetNIndices(); k++) {
768 Bool_t copyindex=kTRUE;
769 for(Int_t l=0; l<ntrks; l++) {
770 if(inindices[k]==id[l]) copyindex=kFALSE;
773 outindices[j] = inindices[k]; j++;
776 outVtx->SetIndices(nIndices,outindices);
777 delete [] outindices;
780 printf("Vertex before removing tracks:\n");
781 inVtx->PrintStatus();
782 inVtx->PrintIndices();
783 printf("Vertex after removing tracks:\n");
784 outVtx->PrintStatus();
785 outVtx->PrintIndices();
790 //---------------------------------------------------------------------------
791 void AliVertexerTracks::SetITSMode(Double_t dcacut,
792 Double_t dcacutIter0,
797 Double_t mindetfitter,
801 // Cut values for ITS mode
804 SetITSrefitRequired();
806 SetDCAcutIter0(dcacutIter0);
808 SetMinITSClusters(minITScls);
809 SetMinTracks(mintrks);
811 SetMinDetFitter(mindetfitter);
816 //---------------------------------------------------------------------------
817 void AliVertexerTracks::SetTPCMode(Double_t dcacut,
818 Double_t dcacutIter0,
823 Double_t mindetfitter,
827 // Cut values for TPC mode
830 SetITSrefitNotRequired();
832 SetDCAcutIter0(dcacutIter0);
834 SetMinITSClusters(minITScls);
835 SetMinTracks(mintrks);
837 SetMinDetFitter(mindetfitter);
842 //---------------------------------------------------------------------------
843 void AliVertexerTracks::SetSkipTracks(Int_t n,Int_t *skipped)
846 // Mark the tracks not to be used in the vertex reconstruction.
847 // Tracks are identified by AliESDtrack::GetID()
849 fNTrksToSkip = n; fTrksToSkip = new Int_t[n];
850 for(Int_t i=0;i<n;i++) fTrksToSkip[i] = skipped[i];
853 //---------------------------------------------------------------------------
854 void AliVertexerTracks::SetVtxStart(AliESDVertex *vtx)
857 // Set initial vertex knowledge
859 vtx->GetXYZ(fNominalPos);
860 vtx->GetCovMatrix(fNominalCov);
864 //---------------------------------------------------------------------------
865 void AliVertexerTracks::StrLinVertexFinderMinDist(Int_t optUseWeights)
867 AliExternalTrackParam *track1;
868 const Int_t knacc = (Int_t)fTrkArraySel.GetEntriesFast();
869 static TClonesArray linarray("AliStrLine",knacc);
870 for(Int_t i=0; i<knacc; i++){
871 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
872 Double_t alpha=track1->GetAlpha();
873 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
874 Double_t pos[3],dir[3],sigmasq[3];
875 track1->GetXYZAt(mindist,GetFieldkG(),pos);
876 track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
877 sigmasq[0]=TMath::Sin(alpha)*TMath::Sin(alpha)*track1->GetSigmaY2();
878 sigmasq[1]=TMath::Cos(alpha)*TMath::Cos(alpha)*track1->GetSigmaY2();
879 sigmasq[2]=track1->GetSigmaZ2();
882 if(!TrackToPoint(track1,ri,wWi)) continue;
885 for(Int_t ia=0;ia<3;ia++){
886 for(Int_t ib=0;ib<3;ib++){
887 wmat[iel]=wWi(ia,ib);
891 new(linarray[i]) AliStrLine(pos,sigmasq,wmat,dir);
893 fVert=TrackletVertexFinder(&linarray,optUseWeights);
896 //---------------------------------------------------------------------------
897 AliESDVertex AliVertexerTracks::TrackletVertexFinder(TClonesArray *lines, Int_t optUseWeights)
899 // Calculate the point at minimum distance to prepared tracks
901 const Int_t knacc = (Int_t)lines->GetEntriesFast();
902 Double_t initPos[3]={0.,0.,0.};
904 Double_t (*vectP0)[3]=new Double_t [knacc][3];
905 Double_t (*vectP1)[3]=new Double_t [knacc][3];
908 Double_t dsum[3]={0,0,0};
910 for(Int_t i=0;i<3;i++){
911 for(Int_t j=0;j<3;j++){
917 for(Int_t i=0; i<knacc; i++){
918 AliStrLine* line1 = (AliStrLine*)lines->At(i);
919 Double_t p0[3],cd[3],sigmasq[3];
923 line1->GetSigma2P0(sigmasq);
924 line1->GetWMatrix(wmat);
927 for(Int_t ia=0;ia<3;ia++){
928 for(Int_t ib=0;ib<3;ib++){
929 wWi(ia,ib)=wmat[iel];
936 Double_t p1[3]={p0[0]+cd[0],p0[1]+cd[1],p0[2]+cd[2]};
946 if(optUseWeights==0)GetStrLinDerivMatrix(p0,p1,matr,dknow);
947 else GetStrLinDerivMatrix(p0,p1,sigmasq,matr,dknow);
950 for(Int_t iii=0;iii<3;iii++){
951 dsum[iii]+=dknow[iii];
952 for(Int_t lj=0;lj<3;lj++) sum[iii][lj]+=matr[iii][lj];
956 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
957 Double_t covmatrix[6];
958 covmatrix[0] = invsumWi(0,0);
959 covmatrix[1] = invsumWi(0,1);
960 covmatrix[2] = invsumWi(1,1);
961 covmatrix[3] = invsumWi(0,2);
962 covmatrix[4] = invsumWi(1,2);
963 covmatrix[5] = invsumWi(2,2);
966 Double_t det=GetDeterminant3X3(sum);
970 for(Int_t zz=0;zz<3;zz++){
971 for(Int_t ww=0;ww<3;ww++){
972 for(Int_t kk=0;kk<3;kk++) vett[ww][kk]=sum[ww][kk];
974 for(Int_t kk=0;kk<3;kk++) vett[kk][zz]=dsum[kk];
975 initPos[zz]=GetDeterminant3X3(vett)/det;
979 for(Int_t i=0; i<knacc; i++){
980 Double_t p0[3]={0,0,0},p1[3]={0,0,0};
981 for(Int_t ii=0;ii<3;ii++){
982 p0[ii]=vectP0[i][ii];
983 p1[ii]=vectP1[i][ii];
985 sigma+=GetStrLinMinDist(p0,p1,initPos);
988 if(sigma>0.) {sigma=TMath::Sqrt(sigma);}else{sigma=999;}
992 AliESDVertex theVert(initPos,covmatrix,99999.,knacc);
993 theVert.SetDispersion(sigma);
998 //---------------------------------------------------------------------------
999 Bool_t AliVertexerTracks::TrackToPoint(AliExternalTrackParam *t,
1000 TMatrixD &ri,TMatrixD &wWi,
1001 Bool_t uUi3by3) const
1004 // Extract from the AliExternalTrackParam the global coordinates ri and covariance matrix
1005 // wWi of the space point that it represents (to be used in VertexFitter())
1009 Double_t rotAngle = t->GetAlpha();
1010 if(rotAngle<0.) rotAngle += 2.*TMath::Pi();
1011 Double_t cosRot = TMath::Cos(rotAngle);
1012 Double_t sinRot = TMath::Sin(rotAngle);
1014 ri(0,0) = t->GetX()*cosRot-t->GetY()*sinRot;
1015 ri(1,0) = t->GetX()*sinRot+t->GetY()*cosRot;
1016 ri(2,0) = t->GetZ();
1021 // matrix to go from global (x,y,z) to local (y,z);
1030 // covariance matrix of local (y,z) - inverted
1032 uUi(0,0) = t->GetSigmaY2();
1033 uUi(0,1) = t->GetSigmaZY();
1034 uUi(1,0) = t->GetSigmaZY();
1035 uUi(1,1) = t->GetSigmaZ2();
1036 //printf(" Ui :\n");
1037 //printf(" %f %f\n",uUi(0,0),uUi(0,1));
1038 //printf(" %f %f\n",uUi(1,0),uUi(1,1));
1040 if(uUi.Determinant() <= 0.) return kFALSE;
1041 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
1043 // weights matrix: wWi = qQiT * uUiInv * qQi
1044 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
1045 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
1048 if(fVert.GetNContributors()<1) AliFatal("Vertex from finder is empty");
1049 // matrix to go from global (x,y,z) to local (x,y,z);
1061 // covariance of fVert along the track
1062 Double_t p[3],pt,ptot;
1064 pt = TMath::Sqrt(p[0]*p[0]+p[1]*p[1]);
1065 ptot = TMath::Sqrt(pt*pt+p[2]*p[2]);
1066 Double_t cphi = p[0]/pt; //cos(phi)=px/pt
1067 Double_t sphi = p[1]/pt; //sin(phi)=py/pt
1068 Double_t clambda = pt/ptot; //cos(lambda)=pt/ptot
1069 Double_t slambda = p[2]/ptot; //sin(lambda)=pz/ptot
1070 Double_t covfVert[6];
1071 fVert.GetCovMatrix(covfVert);
1072 Double_t covfVertalongt =
1073 covfVert[0]*cphi*cphi*clambda*clambda
1074 +covfVert[1]*2.*cphi*sphi*clambda*clambda
1075 +covfVert[3]*2.*cphi*clambda*slambda
1076 +covfVert[2]*sphi*sphi*clambda*clambda
1077 +covfVert[4]*2.*sphi*clambda*slambda
1078 +covfVert[5]*slambda*slambda;
1079 // covariance matrix of local (x,y,z) - inverted
1081 uUi(0,0) = covfVertalongt * fnSigmaForUi00 * fnSigmaForUi00;
1082 if(fDebug) printf("=====> sqrtUi00 cm %f\n",TMath::Sqrt(uUi(0,0)));
1086 uUi(1,1) = t->GetSigmaY2();
1087 uUi(1,2) = t->GetSigmaZY();
1089 uUi(2,1) = t->GetSigmaZY();
1090 uUi(2,2) = t->GetSigmaZ2();
1091 //printf(" Ui :\n");
1092 //printf(" %f %f\n",uUi(0,0),uUi(0,1));
1093 //printf(" %f %f\n",uUi(1,0),uUi(1,1));
1095 if(uUi.Determinant() <= 0.) return kFALSE;
1096 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
1098 // weights matrix: wWi = qQiT * uUiInv * qQi
1099 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
1100 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
1107 //---------------------------------------------------------------------------
1108 void AliVertexerTracks::TooFewTracks()
1111 // When the number of tracks is < fMinTracks,
1112 // deal with vertices not found and prepare to exit
1114 if(fDebug) printf("TooFewTracks\n");
1116 Double_t pos[3],err[3];
1117 pos[0] = fNominalPos[0];
1118 err[0] = TMath::Sqrt(fNominalCov[0]);
1119 pos[1] = fNominalPos[1];
1120 err[1] = TMath::Sqrt(fNominalCov[2]);
1121 pos[2] = fNominalPos[2];
1122 err[2] = TMath::Sqrt(fNominalCov[5]);
1123 Int_t ncontr = (err[0]>1. ? -1 : -3);
1125 fCurrentVertex = new AliESDVertex(pos,err);
1126 fCurrentVertex->SetNContributors(ncontr);
1129 fCurrentVertex->SetTitle("VertexerTracksWithConstraint");
1131 fCurrentVertex->SetTitle("VertexerTracksNoConstraint");
1134 if(!fTrkArraySel.IsEmpty()) fTrkArraySel.Delete();
1135 if(fIdSel) {delete [] fIdSel; fIdSel=NULL;}
1136 if(fTrksToSkip) {delete [] fTrksToSkip; fTrksToSkip=NULL;}
1140 //---------------------------------------------------------------------------
1141 void AliVertexerTracks::VertexFinder(Int_t optUseWeights)
1144 // Get estimate of vertex position in (x,y) from tracks DCA
1146 Double_t initPos[3];
1148 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
1149 Int_t nacc = (Int_t)fTrkArraySel.GetEntriesFast();
1150 Double_t aver[3]={0.,0.,0.};
1151 Double_t aversq[3]={0.,0.,0.};
1152 Double_t sigmasq[3]={0.,0.,0.};
1155 AliExternalTrackParam *track1;
1156 AliExternalTrackParam *track2;
1157 Double_t pos[3],dir[3];
1158 Double_t alpha,mindist;
1160 for(Int_t i=0; i<nacc; i++){
1161 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
1162 alpha=track1->GetAlpha();
1163 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1164 track1->GetXYZAt(mindist,GetFieldkG(),pos);
1165 track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
1166 AliStrLine *line1 = new AliStrLine(pos,dir);
1168 // AliStrLine *line1 = new AliStrLine();
1169 // track1->ApproximateHelixWithLine(mindist,GetFieldkG(),line1);
1171 for(Int_t j=i+1; j<nacc; j++){
1172 track2 = (AliExternalTrackParam*)fTrkArraySel.At(j);
1173 alpha=track2->GetAlpha();
1174 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1175 track2->GetXYZAt(mindist,GetFieldkG(),pos);
1176 track2->GetPxPyPzAt(mindist,GetFieldkG(),dir);
1177 AliStrLine *line2 = new AliStrLine(pos,dir);
1178 // AliStrLine *line2 = new AliStrLine();
1179 // track2->ApproximateHelixWithLine(mindist,GetFieldkG(),line2);
1180 Double_t distCA=line2->GetDCA(line1);
1181 //printf("%d %d %f\n",i,j,distCA);
1182 if(fDCAcut<=0 || (fDCAcut>0&&distCA<fDCAcut)){
1183 Double_t pnt1[3],pnt2[3],crosspoint[3];
1185 if(optUseWeights<=0){
1186 Int_t retcode = line2->Cross(line1,crosspoint);
1189 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
1190 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1193 if(optUseWeights>0){
1194 Int_t retcode = line1->CrossPoints(line2,pnt1,pnt2);
1197 alpha=track1->GetAlpha();
1198 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
1199 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
1200 alpha=track2->GetAlpha();
1201 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
1202 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
1203 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
1204 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
1205 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
1206 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
1207 crosspoint[0]=wx1*pnt1[0] + wx2*pnt2[0];
1208 crosspoint[1]=wy1*pnt1[1] + wy2*pnt2[1];
1209 crosspoint[2]=wz1*pnt1[2] + wz2*pnt2[2];
1212 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
1213 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1222 for(Int_t jj=0;jj<3;jj++){
1223 initPos[jj] = aver[jj]/ncombi;
1224 //printf("%f\n",initPos[jj]);
1226 sigmasq[jj]=aversq[jj]-initPos[jj]*initPos[jj];
1229 sigma=TMath::Sqrt(TMath::Abs(sigma));
1232 Warning("VertexFinder","Finder did not succed");
1235 fVert.SetXYZ(initPos);
1236 fVert.SetDispersion(sigma);
1237 fVert.SetNContributors(ncombi);
1239 //---------------------------------------------------------------------------
1240 void AliVertexerTracks::VertexFitter()
1243 // The optimal estimate of the vertex position is given by a "weighted
1244 // average of tracks positions".
1245 // Original method: V. Karimaki, CMS Note 97/0051
1247 Bool_t useConstraint = fConstraint;
1248 Double_t initPos[3];
1250 fVert.GetXYZ(initPos);
1252 initPos[0]=fNominalPos[0];
1253 initPos[1]=fNominalPos[1];
1254 initPos[2]=fNominalPos[2];
1257 Int_t nTrksSel = (Int_t)fTrkArraySel.GetEntries();
1258 if(nTrksSel==1) useConstraint=kTRUE;
1260 printf("--- VertexFitter(): start\n");
1261 printf(" Number of tracks in array: %d\n",nTrksSel);
1262 printf(" Minimum # tracks required in fit: %d\n",fMinTracks);
1263 printf(" Vertex position after finder: %f,%f,%f\n",initPos[0],initPos[1],initPos[2]);
1264 if(useConstraint) printf(" This vertex will be used in fit: (%f+-%f,%f+-%f)\n",fNominalPos[0],TMath::Sqrt(fNominalCov[0]),fNominalPos[1],TMath::Sqrt(fNominalCov[2]));
1267 // special treatment for few-tracks fits (e.g. secondary vertices)
1268 Bool_t uUi3by3 = kFALSE; if(nTrksSel<5 && !useConstraint) uUi3by3 = kTRUE;
1273 rv(0,0) = initPos[0];
1274 rv(1,0) = initPos[1];
1276 Double_t xlStart,alpha;
1278 Double_t chi2,chi2i,chi2b;
1279 AliExternalTrackParam *t = 0;
1282 // initial vertex covariance matrix
1284 vVb(0,0) = fNominalCov[0];
1285 vVb(0,1) = fNominalCov[1];
1287 vVb(1,0) = fNominalCov[1];
1288 vVb(1,1) = fNominalCov[2];
1292 vVb(2,2) = fNominalCov[5];
1293 TMatrixD vVbInv(TMatrixD::kInverted,vVb);
1295 rb(0,0) = fNominalPos[0];
1296 rb(1,0) = fNominalPos[1];
1297 rb(2,0) = fNominalPos[2];
1298 TMatrixD vVbInvrb(vVbInv,TMatrixD::kMult,rb);
1302 // 1st - estimate of vtx using all tracks
1303 // 2nd - estimate of global chi2
1304 for(step=0; step<2; step++) {
1305 if(fDebug) printf(" step = %d\n",step);
1309 if(step==1) { initPos[0]=rv(0,0); initPos[0]=rv(1,0); }
1311 TMatrixD sumWiri(3,1);
1312 TMatrixD sumWi(3,3);
1313 for(i=0; i<3; i++) {
1315 for(j=0; j<3; j++) sumWi(j,i) = 0.;
1318 // mean vertex constraint
1321 sumWiri(i,0) += vVbInvrb(i,0);
1322 for(k=0;k<3;k++) sumWi(i,k) += vVbInv(i,k);
1325 TMatrixD deltar = rv; deltar -= rb;
1326 TMatrixD vVbInvdeltar(vVbInv,TMatrixD::kMult,deltar);
1327 chi2b = deltar(0,0)*vVbInvdeltar(0,0)+
1328 deltar(1,0)*vVbInvdeltar(1,0)+
1329 deltar(2,0)*vVbInvdeltar(2,0);
1334 for(k=0; k<nTrksSel; k++) {
1335 // get track from track array
1336 t = (AliExternalTrackParam*)fTrkArraySel.At(k);
1337 alpha = t->GetAlpha();
1338 xlStart = initPos[0]*TMath::Cos(alpha)+initPos[1]*TMath::Sin(alpha);
1339 // to vtxSeed (from finder)
1340 t->PropagateTo(xlStart,GetFieldkG());
1342 // vector of track global coordinates
1344 // covariance matrix of ri
1347 // get space point from track
1348 if(!TrackToPoint(t,ri,wWi,uUi3by3)) continue;
1349 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
1352 TMatrixD deltar = rv; deltar -= ri;
1353 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
1354 chi2i = deltar(0,0)*wWideltar(0,0)+
1355 deltar(1,0)*wWideltar(1,0)+
1356 deltar(2,0)*wWideltar(2,0);
1358 // add to total chi2
1365 } // end loop on tracks
1367 if(nTrksUsed < fMinTracks) {
1372 Double_t determinant = sumWi.Determinant();
1373 if(determinant < fMinDetFitter) {
1374 printf("det(V) = %f (<%f)\n",determinant,fMinDetFitter);
1380 // inverted of weights matrix
1381 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
1383 // position of primary vertex
1384 rv.Mult(vV,sumWiri);
1386 } // end loop on the 2 steps
1393 Double_t position[3];
1394 position[0] = rv(0,0);
1395 position[1] = rv(1,0);
1396 position[2] = rv(2,0);
1397 Double_t covmatrix[6];
1398 covmatrix[0] = vV(0,0);
1399 covmatrix[1] = vV(0,1);
1400 covmatrix[2] = vV(1,1);
1401 covmatrix[3] = vV(0,2);
1402 covmatrix[4] = vV(1,2);
1403 covmatrix[5] = vV(2,2);
1405 // for correct chi2/ndf, count constraint as additional "track"
1406 if(fConstraint) nTrksUsed++;
1407 // store data in the vertex object
1408 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nTrksUsed);
1411 printf(" Vertex after fit:\n");
1412 fCurrentVertex->PrintStatus();
1413 printf("--- VertexFitter(): finish\n");
1418 //----------------------------------------------------------------------------
1419 AliESDVertex* AliVertexerTracks::VertexForSelectedTracks(TObjArray *trkArray,
1421 Bool_t optUseFitter,
1422 Bool_t optPropagate)
1425 // Return vertex from tracks (AliExternalTrackParam) in array
1430 // get tracks and propagate them to initial vertex position
1431 fIdSel = new UShort_t[(Int_t)trkArray->GetEntriesFast()];
1432 Int_t nTrksSel = PrepareTracks(*trkArray,id,0);
1433 if(nTrksSel < TMath::Max(2,fMinTracks)) {
1435 return fCurrentVertex;
1440 case 1: StrLinVertexFinderMinDist(1); break;
1441 case 2: StrLinVertexFinderMinDist(0); break;
1442 case 3: HelixVertexFinder(); break;
1443 case 4: VertexFinder(1); break;
1444 case 5: VertexFinder(0); break;
1445 default: printf("Wrong algorithm\n"); break;
1447 if(fDebug) printf(" Vertex finding completed\n");
1453 Double_t position[3]={fVert.GetXv(),fVert.GetYv(),fVert.GetZv()};
1454 Double_t covmatrix[6];
1455 fVert.GetCovMatrix(covmatrix);
1456 Double_t chi2=99999.;
1457 Int_t nTrksUsed=fVert.GetNContributors();
1458 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nTrksUsed);
1460 fCurrentVertex->SetDispersion(fVert.GetDispersion());
1463 // set indices of used tracks and propagate track to found vertex
1464 UShort_t *indices = 0;
1465 Double_t d0z0[2],covd0z0[3];
1466 AliExternalTrackParam *t = 0;
1467 if(fCurrentVertex->GetNContributors()>0) {
1468 indices = new UShort_t[fCurrentVertex->GetNContributors()];
1469 for(Int_t jj=0; jj<(Int_t)fTrkArraySel.GetEntriesFast(); jj++) {
1470 indices[jj] = fIdSel[jj];
1471 t = (AliExternalTrackParam*)fTrkArraySel.At(jj);
1472 if(optPropagate && optUseFitter) {
1473 if(TMath::Sqrt(fCurrentVertex->GetXv()*fCurrentVertex->GetXv()+fCurrentVertex->GetYv()*fCurrentVertex->GetYv())<3.) {
1474 t->PropagateToDCA(fCurrentVertex,GetFieldkG(),100.,d0z0,covd0z0);
1475 if(fDebug) printf("Track %d propagated to found vertex\n",jj);
1477 AliWarning("Found vertex outside beam pipe!");
1481 fCurrentVertex->SetIndices(fCurrentVertex->GetNContributors(),indices);
1485 delete [] indices; indices=NULL;
1486 delete [] fIdSel; fIdSel=NULL;
1487 fTrkArraySel.Delete();
1489 return fCurrentVertex;
1491 //----------------------------------------------------------------------------
1492 AliESDVertex* AliVertexerTracks::VertexForSelectedESDTracks(TObjArray *trkArray,
1493 Bool_t optUseFitter,
1494 Bool_t optPropagate)
1497 // Return vertex from array of ESD tracks
1500 Int_t nTrks = (Int_t)trkArray->GetEntriesFast();
1501 UShort_t *id = new UShort_t[nTrks];
1503 AliESDtrack *esdt = 0;
1504 for(Int_t i=0; i<nTrks; i++){
1505 esdt = (AliESDtrack*)trkArray->At(i);
1506 id[i] = (UShort_t)esdt->GetID();
1509 VertexForSelectedTracks(trkArray,id,optUseFitter,optPropagate);
1511 delete [] id; id=NULL;
1513 return fCurrentVertex;
1515 //--------------------------------------------------------------------------