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():
73 // Default constructor
78 //----------------------------------------------------------------------------
79 AliVertexerTracks::AliVertexerTracks(Double_t fieldkG):
107 // Standard constructor
113 //-----------------------------------------------------------------------------
114 AliVertexerTracks::~AliVertexerTracks()
116 // Default Destructor
117 // The objects pointed by the following pointer are not owned
118 // by this class and are not deleted
120 if(fTrksToSkip) { delete [] fTrksToSkip; fTrksToSkip=NULL; }
121 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
123 //----------------------------------------------------------------------------
124 AliESDVertex* AliVertexerTracks::FindPrimaryVertex(const AliESDEvent *esdEvent)
127 // Primary vertex for current ESD event
129 // 1st with 5*fNSigma*sigma cut w.r.t. to initial vertex
130 // + cut on sqrt(d0d0+z0z0) if fConstraint=kFALSE
131 // 2nd with fNSigma*sigma cut w.r.t. to vertex found in 1st iteration)
135 // accept 1-track case only if constraint is available
136 if(!fConstraint && fMinTracks==1) fMinTracks=2;
138 // read tracks from ESD
139 Int_t nTrks = (Int_t)esdEvent->GetNumberOfTracks();
140 if(nTrks<fMinTracks) {
142 return fCurrentVertex;
146 TDirectory * olddir = gDirectory;
148 if(nTrks>500) f = new TFile("VertexerTracks.root","recreate");
149 TObjArray trkArrayOrig(nTrks);
150 UShort_t *idOrig = new UShort_t[nTrks];
153 AliExternalTrackParam *t=0;
154 // loop on ESD tracks
155 for(Int_t i=0; i<nTrks; i++) {
156 AliESDtrack *esdt = esdEvent->GetTrack(i);
157 // check tracks to skip
158 Bool_t skipThis = kFALSE;
159 for(Int_t j=0; j<fNTrksToSkip; j++) {
160 if(esdt->GetID()==fTrksToSkip[j]) {
161 if(fDebug) printf("skipping track: %d\n",i);
165 if(skipThis) continue;
167 // check number of clusters in ITS or TPC
168 if(esdt->GetNcls(fMode) < fMinClusters) continue;
170 if(fMode==0) { // ITS mode
171 if(fITSrefit && !(esdt->GetStatus()&AliESDtrack::kITSrefit)) continue;
172 Double_t x,p[5],cov[15];
173 esdt->GetExternalParameters(x,p);
174 esdt->GetExternalCovariance(cov);
175 t = new AliExternalTrackParam(x,esdt->GetAlpha(),p,cov);
176 } else if(fMode==1) { // TPC mode
177 t = (AliExternalTrackParam*)esdt->GetTPCInnerParam();
179 Double_t radius = 2.8; //something less than the beam pipe radius
180 if(!PropagateTrackTo(t,radius)) continue;
182 trkArrayOrig.AddLast(t);
183 idOrig[nTrksOrig]=(UShort_t)esdt->GetID();
185 } // end loop on ESD tracks
187 // call method that will reconstruct the vertex
188 FindPrimaryVertex(&trkArrayOrig,idOrig);
190 if(fMode==0) trkArrayOrig.Delete();
191 delete [] idOrig; idOrig=NULL;
194 f->Close(); delete f; f = NULL;
195 gSystem->Unlink("VertexerTracks.root");
199 return fCurrentVertex;
201 //----------------------------------------------------------------------------
202 AliESDVertex* AliVertexerTracks::FindPrimaryVertex(TObjArray *trkArrayOrig,
206 // Primary vertex using the AliExternalTrackParam's in the TObjArray.
207 // idOrig must contain the track IDs from AliESDtrack::GetID()
209 // 1st with 5*fNSigma*sigma cut w.r.t. to initial vertex
210 // + cut on sqrt(d0d0+z0z0) if fConstraint=kFALSE
211 // 2nd with fNSigma*sigma cut w.r.t. to vertex found in 1st iteration)
215 // accept 1-track case only if constraint is available
216 if(!fConstraint && fMinTracks==1) fMinTracks=2;
218 // read tracks from array
219 Int_t nTrksOrig = (Int_t)trkArrayOrig->GetEntriesFast();
220 if(fDebug) printf("Initial number of tracks: %d\n",nTrksOrig);
221 if(nTrksOrig<fMinTracks) {
222 if(fDebug) printf("TooFewTracks\n");
224 return fCurrentVertex;
227 // If fConstraint=kFALSE
228 // run VertexFinder(1) to get rough estimate of initVertex (x,y)
230 // fill fTrkArraySel, for VertexFinder()
231 fIdSel = new UShort_t[nTrksOrig];
232 PrepareTracks(*trkArrayOrig,idOrig,0);
233 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
234 Double_t cutsave = fDCAcut;
235 fDCAcut = fDCAcutIter0;
236 VertexFinder(1); // using weights, cutting dca < fDCAcutIter0
238 if(fVert.GetNContributors()>0) {
239 fVert.GetXYZ(fNominalPos);
240 fNominalPos[0] = fVert.GetXv();
241 fNominalPos[1] = fVert.GetYv();
242 fNominalPos[2] = fVert.GetZv();
243 if(fDebug) printf("No mean vertex: VertexFinder gives (%f, %f, %f)\n",fNominalPos[0],fNominalPos[1],fNominalPos[2]);
248 if(fDebug) printf("No mean vertex and VertexFinder failed\n");
255 // propagate tracks to fNominalPos vertex
257 // if(constraint) reject for |d0|>5*fNSigma*sigma w.r.t. fNominal... vertex
258 // else reject for |d0|\oplus|z0| > 5 mm w.r.t. fNominal... vertex
260 // propagate tracks to best between initVertex and fCurrentVertex
261 // preselect tracks (reject for |d0|>fNSigma*sigma w.r.t. best
262 // between initVertex and fCurrentVertex)
263 for(Int_t iter=1; iter<=2; iter++) {
264 if(fOnlyFitter && iter==1) continue;
265 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
266 fIdSel = new UShort_t[nTrksOrig];
267 Int_t nTrksSel = PrepareTracks(*trkArrayOrig,idOrig,iter);
268 if(fDebug) printf("N tracks selected in iteration %d: %d\n",iter,nTrksSel);
269 if(nTrksSel < fMinTracks) {
271 return fCurrentVertex;
277 if(fDebug) printf("Just one track\n");
278 OneTrackVertFinder();
281 case 1: StrLinVertexFinderMinDist(1); break;
282 case 2: StrLinVertexFinderMinDist(0); break;
283 case 3: HelixVertexFinder(); break;
284 case 4: VertexFinder(1); break;
285 case 5: VertexFinder(0); break;
286 default: printf("Wrong algorithm\n"); break;
289 if(fDebug) printf(" Vertex finding completed\n");
294 } // end loop on the two iterations
297 // set indices of used tracks
298 UShort_t *indices = 0;
299 if(fCurrentVertex->GetNContributors()>0) {
300 Int_t nIndices = (Int_t)fTrkArraySel.GetEntriesFast();
301 indices = new UShort_t[nIndices];
302 for(Int_t jj=0; jj<nIndices; jj++)
303 indices[jj] = fIdSel[jj];
304 fCurrentVertex->SetIndices(nIndices,indices);
306 delete [] indices; indices=NULL;
310 TString title="VertexerTracksNoConstraint";
312 title="VertexerTracksWithConstraint";
313 if(fOnlyFitter) title.Append("OnlyFitter");
315 fCurrentVertex->SetTitle(title.Data());
319 fCurrentVertex->PrintStatus();
320 fCurrentVertex->PrintIndices();
324 delete [] fIdSel; fIdSel=NULL;
325 fTrkArraySel.Delete();
326 if(fTrksToSkip) { delete [] fTrksToSkip; fTrksToSkip=NULL; }
329 return fCurrentVertex;
331 //------------------------------------------------------------------------
332 Double_t AliVertexerTracks::GetDeterminant3X3(Double_t matr[][3])
335 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];
338 //-------------------------------------------------------------------------
339 void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t (*m)[3],Double_t *d)
342 Double_t x12=p0[0]-p1[0];
343 Double_t y12=p0[1]-p1[1];
344 Double_t z12=p0[2]-p1[2];
345 Double_t kk=x12*x12+y12*y12+z12*z12;
346 m[0][0]=2-2/kk*x12*x12;
347 m[0][1]=-2/kk*x12*y12;
348 m[0][2]=-2/kk*x12*z12;
349 m[1][0]=-2/kk*x12*y12;
350 m[1][1]=2-2/kk*y12*y12;
351 m[1][2]=-2/kk*y12*z12;
352 m[2][0]=-2/kk*x12*z12;
354 m[2][2]=2-2/kk*z12*z12;
355 d[0]=2*p0[0]-2/kk*p0[0]*x12*x12-2/kk*p0[2]*x12*z12-2/kk*p0[1]*x12*y12;
356 d[1]=2*p0[1]-2/kk*p0[1]*y12*y12-2/kk*p0[0]*x12*y12-2/kk*p0[2]*z12*y12;
357 d[2]=2*p0[2]-2/kk*p0[2]*z12*z12-2/kk*p0[0]*x12*z12-2/kk*p0[1]*z12*y12;
360 //--------------------------------------------------------------------------
361 void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t *sigmasq,Double_t (*m)[3],Double_t *d)
364 Double_t x12=p1[0]-p0[0];
365 Double_t y12=p1[1]-p0[1];
366 Double_t z12=p1[2]-p0[2];
368 Double_t den= x12*x12*sigmasq[1]*sigmasq[2]+y12*y12*sigmasq[0]*sigmasq[2]+z12*z12*sigmasq[0]*sigmasq[1];
370 Double_t kk= 2*(x12*x12/sigmasq[0]+y12*y12/sigmasq[1]+z12*z12/sigmasq[2]);
373 cc[0]=-x12/sigmasq[0];
374 cc[1]=-y12/sigmasq[1];
375 cc[2]=-z12/sigmasq[2];
377 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;
379 Double_t ss= -p0[0]*cc[0]-p0[1]*cc[1]-p0[2]*cc[2];
382 aa[0]=x12*sigmasq[1]*sigmasq[2]/den;
383 aa[1]=y12*sigmasq[0]*sigmasq[2]/den;
384 aa[2]=z12*sigmasq[0]*sigmasq[1]/den;
386 m[0][0]=aa[0]*(aa[0]*kk+2*cc[0])+2*cc[0]*aa[0]+2/sigmasq[0];
387 m[0][1]=aa[1]*(aa[0]*kk+2*cc[0])+2*cc[1]*aa[0];
388 m[0][2]=aa[2]*(aa[0]*kk+2*cc[0])+2*cc[2]*aa[0];
390 m[1][0]=aa[0]*(aa[1]*kk+2*cc[1])+2*cc[0]*aa[1];
391 m[1][1]=aa[1]*(aa[1]*kk+2*cc[1])+2*cc[1]*aa[1]+2/sigmasq[1];
392 m[1][2]=aa[2]*(aa[1]*kk+2*cc[1])+2*cc[2]*aa[1];
394 m[2][0]=aa[0]*(aa[2]*kk+2*cc[2])+2*cc[0]*aa[2];
395 m[2][1]=aa[1]*(aa[2]*kk+2*cc[2])+2*cc[1]*aa[2];
396 m[2][2]=aa[2]*(aa[2]*kk+2*cc[2])+2*cc[2]*aa[2]+2/sigmasq[2];
398 d[0]=-ww*(aa[0]*kk+2*cc[0])-2*ss*aa[0]+2*p0[0]/sigmasq[0];
399 d[1]=-ww*(aa[1]*kk+2*cc[1])-2*ss*aa[1]+2*p0[1]/sigmasq[1];
400 d[2]=-ww*(aa[2]*kk+2*cc[2])-2*ss*aa[2]+2*p0[2]/sigmasq[2];
403 //--------------------------------------------------------------------------
404 Double_t AliVertexerTracks::GetStrLinMinDist(Double_t *p0,Double_t *p1,Double_t *x0)
407 Double_t x12=p0[0]-p1[0];
408 Double_t y12=p0[1]-p1[1];
409 Double_t z12=p0[2]-p1[2];
410 Double_t x10=p0[0]-x0[0];
411 Double_t y10=p0[1]-x0[1];
412 Double_t z10=p0[2]-x0[2];
413 // 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);
414 return ((y10*z12-z10*y12)*(y10*z12-z10*y12)+
415 (z10*x12-x10*z12)*(z10*x12-x10*z12)+
416 (x10*y12-y10*x12)*(x10*y12-y10*x12))
417 /(x12*x12+y12*y12+z12*z12);
419 //---------------------------------------------------------------------------
420 void AliVertexerTracks::OneTrackVertFinder()
422 // find vertex for events with 1 track, using DCA to nominal beam axis
423 if(fDebug) printf("Number of prepared tracks =%d - Call OneTrackVertFinder",fTrkArraySel.GetEntries());
424 AliExternalTrackParam *track1;
425 track1 = (AliExternalTrackParam*)fTrkArraySel.At(0);
426 Double_t alpha=track1->GetAlpha();
427 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
428 Double_t pos[3],dir[3];
429 track1->GetXYZAt(mindist,GetFieldkG(),pos);
430 track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
431 AliStrLine *line1 = new AliStrLine(pos,dir);
432 Double_t p1[3]={fNominalPos[0],fNominalPos[1],0.};
433 Double_t p2[3]={fNominalPos[0],fNominalPos[1],10.};
434 AliStrLine *zeta=new AliStrLine(p1,p2,kTRUE);
435 Double_t crosspoint[3]={0.,0.,0.};
438 Int_t retcode = zeta->Cross(line1,crosspoint);
440 sigma=line1->GetDistFromPoint(crosspoint);
445 fVert.SetXYZ(crosspoint);
446 fVert.SetDispersion(sigma);
447 fVert.SetNContributors(nContrib);
449 //---------------------------------------------------------------------------
450 void AliVertexerTracks::HelixVertexFinder()
452 // Get estimate of vertex position in (x,y) from tracks DCA
457 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
459 Int_t nacc = (Int_t)fTrkArraySel.GetEntriesFast();
461 Double_t aver[3]={0.,0.,0.};
462 Double_t averquad[3]={0.,0.,0.};
463 Double_t sigmaquad[3]={0.,0.,0.};
466 AliExternalTrackParam *track1;
467 AliExternalTrackParam *track2;
470 Double_t alpha, cs, sn;
471 Double_t crosspoint[3];
472 for(Int_t i=0; i<nacc; i++){
473 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
476 for(Int_t j=i+1; j<nacc; j++){
477 track2 = (AliExternalTrackParam*)fTrkArraySel.At(j);
479 distCA=track2->PropagateToDCA(track1,GetFieldkG());
480 if(fDCAcut<=0 ||(fDCAcut>0&&distCA<fDCAcut)){
482 alpha=track1->GetAlpha();
483 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
484 Double_t x1=x*cs - track1->GetY()*sn;
485 Double_t y1=x*sn + track1->GetY()*cs;
486 Double_t z1=track1->GetZ();
488 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
490 alpha=track2->GetAlpha();
491 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
492 Double_t x2=x*cs - track2->GetY()*sn;
493 Double_t y2=x*sn + track2->GetY()*cs;
494 Double_t z2=track2->GetZ();
495 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
496 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
497 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
498 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
499 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
500 crosspoint[0]=wx1*x1 + wx2*x2;
501 crosspoint[1]=wy1*y1 + wy2*y2;
502 crosspoint[2]=wz1*z1 + wz2*z2;
505 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
506 for(Int_t jj=0;jj<3;jj++)averquad[jj]+=(crosspoint[jj]*crosspoint[jj]);
512 for(Int_t jj=0;jj<3;jj++){
513 initPos[jj] = aver[jj]/ncombi;
514 averquad[jj]/=ncombi;
515 sigmaquad[jj]=averquad[jj]-initPos[jj]*initPos[jj];
516 sigma+=sigmaquad[jj];
518 sigma=TMath::Sqrt(TMath::Abs(sigma));
521 Warning("HelixVertexFinder","Finder did not succed");
524 fVert.SetXYZ(initPos);
525 fVert.SetDispersion(sigma);
526 fVert.SetNContributors(ncombi);
528 //----------------------------------------------------------------------------
529 Int_t AliVertexerTracks::PrepareTracks(TObjArray &trkArrayOrig,
534 // Propagate tracks to initial vertex position and store them in a TObjArray
536 if(fDebug) printf(" PrepareTracks()\n");
538 Int_t nTrksOrig = (Int_t)trkArrayOrig.GetEntriesFast();
541 Double_t sigmaCurr[3];
542 Double_t normdistx,normdisty;
543 Double_t d0z0[2],covd0z0[3];
546 AliESDVertex *initVertex = new AliESDVertex(fNominalPos,fNominalCov,1,1);
548 if(!fTrkArraySel.IsEmpty()) fTrkArraySel.Delete();
550 AliExternalTrackParam *track=0;
553 for(Int_t i=0; i<nTrksOrig; i++) {
554 track = new AliExternalTrackParam(*(AliExternalTrackParam*)trkArrayOrig.At(i));
556 if(TMath::Abs(track->GetTgl())>fMaxTgl) {
557 if(fDebug) printf(" rejecting track with tgl = %f\n",track->GetTgl());
558 delete track; continue;
561 // propagate track to vertex
562 if(optImpParCut<2 || fOnlyFitter) { // optImpParCut==1 or 0
563 track->PropagateToDCA(initVertex,GetFieldkG(),100.,d0z0,covd0z0);
564 } else { // optImpParCut==2
565 fCurrentVertex->GetSigmaXYZ(sigmaCurr);
566 normdistx = TMath::Abs(fCurrentVertex->GetXv()-fNominalPos[0])/TMath::Sqrt(sigmaCurr[0]*sigmaCurr[0]+fNominalCov[0]);
567 normdisty = TMath::Abs(fCurrentVertex->GetYv()-fNominalPos[1])/TMath::Sqrt(sigmaCurr[1]*sigmaCurr[1]+fNominalCov[2]);
568 if(normdistx < 3. && normdisty < 3. &&
569 (sigmaCurr[0]+sigmaCurr[1])<(TMath::Sqrt(fNominalCov[0])+TMath::Sqrt(fNominalCov[2]))) {
570 track->PropagateToDCA(fCurrentVertex,GetFieldkG(),100.,d0z0,covd0z0);
572 track->PropagateToDCA(initVertex,GetFieldkG(),100.,d0z0,covd0z0);
576 sigmad0 = TMath::Sqrt(covd0z0[0]);
577 maxd0rphi = fNSigma*sigmad0;
578 if(optImpParCut==1) maxd0rphi *= 5.;
579 maxd0rphi = TMath::Min(maxd0rphi,fFiducialR);
580 //sigmad0z0 = TMath::Sqrt(covd0z0[0]+covd0z0[2]); // for future improvement
581 //maxd0z0 = 10.*fNSigma*sigmad0z0;
583 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);
586 //---- track selection based on impact parameters ----//
588 // always reject tracks outside fiducial volume
589 if(TMath::Abs(d0z0[0])>fFiducialR || TMath::Abs(d0z0[1])>fFiducialZ) {
590 if(fDebug) printf(" rejected\n");
591 delete track; continue;
594 // during iterations 1 and 2 , reject tracks with d0rphi > maxd0rphi
595 if(optImpParCut>0 && TMath::Abs(d0z0[0])>maxd0rphi) {
596 if(fDebug) printf(" rejected\n");
597 delete track; continue;
600 // if fConstraint=kFALSE, during iterations 1 and 2 ||
601 // if fConstraint=kTRUE, during iteration 2,
602 // select tracks with d0oplusz0 < fMaxd0z0
603 if((!fConstraint && optImpParCut>0 && fVert.GetNContributors()>0) ||
604 ( fConstraint && optImpParCut==2)) {
606 TMath::Sqrt(d0z0[0]*d0z0[0]+d0z0[1]*d0z0[1])>fMaxd0z0) {
607 if(fDebug) printf(" rejected\n");
608 delete track; continue;
612 // track passed all selections
613 fTrkArraySel.AddLast(track);
614 fIdSel[nTrksSel] = idOrig[i];
616 } // end loop on tracks
622 //----------------------------------------------------------------------------
623 Bool_t AliVertexerTracks::PropagateTrackTo(AliExternalTrackParam *track,
625 //----------------------------------------------------------------
626 // COPIED from AliTracker
628 // Propagates the track to the plane X=xk (cm).
630 // Origin: Marian Ivanov, Marian.Ivanov@cern.ch
631 //----------------------------------------------------------------
633 const Double_t kEpsilon = 0.00001;
634 Double_t xpos = track->GetX();
635 Double_t dir = (xpos<xToGo) ? 1. : -1.;
636 Double_t maxStep = 5;
637 Double_t maxSnp = 0.8;
639 while ( (xToGo-xpos)*dir > kEpsilon){
640 Double_t step = dir*TMath::Min(TMath::Abs(xToGo-xpos), maxStep);
641 Double_t x = xpos+step;
642 Double_t xyz0[3],xyz1[3];
643 track->GetXYZ(xyz0); //starting global position
645 if(!track->GetXYZAt(x,GetFieldkG(),xyz1)) return kFALSE; // no prolongation
646 xyz1[2]+=kEpsilon; // waiting for bug correction in geo
648 if(TMath::Abs(track->GetSnpAt(x,GetFieldkG())) >= maxSnp) return kFALSE;
649 if(!track->PropagateTo(x,GetFieldkG())) return kFALSE;
651 if(TMath::Abs(track->GetSnp()) >= maxSnp) return kFALSE;
652 track->GetXYZ(xyz0); // global position
653 Double_t alphan = TMath::ATan2(xyz0[1], xyz0[0]);
655 Double_t ca=TMath::Cos(alphan-track->GetAlpha()),
656 sa=TMath::Sin(alphan-track->GetAlpha());
657 Double_t sf=track->GetSnp(), cf=TMath::Sqrt(1.- sf*sf);
658 Double_t sinNew = sf*ca - cf*sa;
659 if(TMath::Abs(sinNew) >= maxSnp) return kFALSE;
660 if(!track->Rotate(alphan)) return kFALSE;
662 xpos = track->GetX();
666 //---------------------------------------------------------------------------
667 AliESDVertex* AliVertexerTracks::RemoveTracksFromVertex(AliESDVertex *inVtx,
673 // Removes tracks in trksTree from fit of inVtx
676 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraint")) {
677 printf("ERROR: primary vertex has no constraint: cannot remove tracks\n");
680 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraintOnlyFitter"))
681 printf("WARNING: result of tracks' removal will be only approximately correct\n");
684 rv(0,0) = inVtx->GetXv();
685 rv(1,0) = inVtx->GetYv();
686 rv(2,0) = inVtx->GetZv();
689 inVtx->GetCovMatrix(cov);
691 vV(0,1) = cov[1]; vV(1,0) = cov[1];
693 vV(0,2) = cov[3]; vV(2,0) = cov[3];
694 vV(1,2) = cov[4]; vV(2,1) = cov[4];
697 TMatrixD sumWi(TMatrixD::kInverted,vV);
698 TMatrixD sumWiri(sumWi,TMatrixD::kMult,rv);
700 Int_t nUsedTrks = inVtx->GetNIndices();
701 Double_t chi2 = inVtx->GetChi2();
703 AliExternalTrackParam *track = 0;
704 Int_t ntrks = (Int_t)trkArray->GetEntriesFast();
705 for(Int_t i=0;i<ntrks;i++) {
706 track = (AliExternalTrackParam*)trkArray->At(i);
707 if(!inVtx->UsesTrack(id[i])) {
708 printf("track %d was not used in vertex fit\n",id[i]);
711 Double_t alpha = track->GetAlpha();
712 Double_t xl = diamondxy[0]*TMath::Cos(alpha)+diamondxy[1]*TMath::Sin(alpha);
713 track->PropagateTo(xl,GetFieldkG());
714 // vector of track global coordinates
716 // covariance matrix of ri
719 // get space point from track
720 if(!TrackToPoint(track,ri,wWi)) continue;
722 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
728 TMatrixD deltar = rv; deltar -= ri;
729 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
730 Double_t chi2i = deltar(0,0)*wWideltar(0,0)+
731 deltar(1,0)*wWideltar(1,0)+
732 deltar(2,0)*wWideltar(2,0);
733 // remove from total chi2
738 printf("Trying to remove too many tracks!\n");
746 // new inverted of weights matrix
747 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
749 // new position of primary vertex
750 rvnew.Mult(vVnew,sumWiri);
752 Double_t position[3];
753 position[0] = rvnew(0,0);
754 position[1] = rvnew(1,0);
755 position[2] = rvnew(2,0);
763 // store data in the vertex object
764 AliESDVertex *outVtx = new AliESDVertex(position,cov,chi2,nUsedTrks);
765 outVtx->SetTitle(inVtx->GetTitle());
766 UShort_t *inindices = inVtx->GetIndices();
767 Int_t nIndices = nUsedTrks;
768 UShort_t *outindices = new UShort_t[nIndices];
770 for(Int_t k=0; k<inVtx->GetNIndices(); k++) {
771 Bool_t copyindex=kTRUE;
772 for(Int_t l=0; l<ntrks; l++) {
773 if(inindices[k]==id[l]) copyindex=kFALSE;
776 outindices[j] = inindices[k]; j++;
779 outVtx->SetIndices(nIndices,outindices);
780 delete [] outindices;
783 printf("Vertex before removing tracks:\n");
784 inVtx->PrintStatus();
785 inVtx->PrintIndices();
786 printf("Vertex after removing tracks:\n");
787 outVtx->PrintStatus();
788 outVtx->PrintIndices();
793 //---------------------------------------------------------------------------
794 void AliVertexerTracks::SetITSMode(Double_t dcacut,
795 Double_t dcacutIter0,
800 Double_t mindetfitter,
806 // Cut values for ITS mode
809 SetITSrefitRequired();
811 SetDCAcutIter0(dcacutIter0);
813 SetMinClusters(minCls);
814 SetMinTracks(mintrks);
816 SetMinDetFitter(mindetfitter);
818 SetFiducialRZ(fidR,fidZ);
822 //---------------------------------------------------------------------------
823 void AliVertexerTracks::SetTPCMode(Double_t dcacut,
824 Double_t dcacutIter0,
829 Double_t mindetfitter,
835 // Cut values for TPC mode
838 SetITSrefitNotRequired();
840 SetDCAcutIter0(dcacutIter0);
842 SetMinClusters(minCls);
843 SetMinTracks(mintrks);
845 SetMinDetFitter(mindetfitter);
847 SetFiducialRZ(fidR,fidZ);
851 //---------------------------------------------------------------------------
852 void AliVertexerTracks::SetSkipTracks(Int_t n,Int_t *skipped)
855 // Mark the tracks not to be used in the vertex reconstruction.
856 // Tracks are identified by AliESDtrack::GetID()
858 fNTrksToSkip = n; fTrksToSkip = new Int_t[n];
859 for(Int_t i=0;i<n;i++) fTrksToSkip[i] = skipped[i];
862 //---------------------------------------------------------------------------
863 void AliVertexerTracks::SetVtxStart(AliESDVertex *vtx)
866 // Set initial vertex knowledge
868 vtx->GetXYZ(fNominalPos);
869 vtx->GetCovMatrix(fNominalCov);
873 //---------------------------------------------------------------------------
874 void AliVertexerTracks::StrLinVertexFinderMinDist(Int_t optUseWeights)
876 AliExternalTrackParam *track1;
877 const Int_t knacc = (Int_t)fTrkArraySel.GetEntriesFast();
878 static TClonesArray linarray("AliStrLine",knacc);
879 for(Int_t i=0; i<knacc; i++){
880 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
881 Double_t alpha=track1->GetAlpha();
882 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
883 Double_t pos[3],dir[3],sigmasq[3];
884 track1->GetXYZAt(mindist,GetFieldkG(),pos);
885 track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
886 sigmasq[0]=TMath::Sin(alpha)*TMath::Sin(alpha)*track1->GetSigmaY2();
887 sigmasq[1]=TMath::Cos(alpha)*TMath::Cos(alpha)*track1->GetSigmaY2();
888 sigmasq[2]=track1->GetSigmaZ2();
891 if(!TrackToPoint(track1,ri,wWi)) continue;
894 for(Int_t ia=0;ia<3;ia++){
895 for(Int_t ib=0;ib<3;ib++){
896 wmat[iel]=wWi(ia,ib);
900 new(linarray[i]) AliStrLine(pos,sigmasq,wmat,dir);
902 fVert=TrackletVertexFinder(&linarray,optUseWeights);
905 //---------------------------------------------------------------------------
906 AliESDVertex AliVertexerTracks::TrackletVertexFinder(TClonesArray *lines, Int_t optUseWeights)
908 // Calculate the point at minimum distance to prepared tracks
910 const Int_t knacc = (Int_t)lines->GetEntriesFast();
911 Double_t initPos[3]={0.,0.,0.};
913 Double_t (*vectP0)[3]=new Double_t [knacc][3];
914 Double_t (*vectP1)[3]=new Double_t [knacc][3];
917 Double_t dsum[3]={0,0,0};
919 for(Int_t i=0;i<3;i++){
920 for(Int_t j=0;j<3;j++){
926 for(Int_t i=0; i<knacc; i++){
927 AliStrLine* line1 = (AliStrLine*)lines->At(i);
928 Double_t p0[3],cd[3],sigmasq[3];
932 line1->GetSigma2P0(sigmasq);
933 line1->GetWMatrix(wmat);
936 for(Int_t ia=0;ia<3;ia++){
937 for(Int_t ib=0;ib<3;ib++){
938 wWi(ia,ib)=wmat[iel];
945 Double_t p1[3]={p0[0]+cd[0],p0[1]+cd[1],p0[2]+cd[2]};
955 if(optUseWeights==0)GetStrLinDerivMatrix(p0,p1,matr,dknow);
956 else GetStrLinDerivMatrix(p0,p1,sigmasq,matr,dknow);
959 for(Int_t iii=0;iii<3;iii++){
960 dsum[iii]+=dknow[iii];
961 for(Int_t lj=0;lj<3;lj++) sum[iii][lj]+=matr[iii][lj];
965 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
966 Double_t covmatrix[6];
967 covmatrix[0] = invsumWi(0,0);
968 covmatrix[1] = invsumWi(0,1);
969 covmatrix[2] = invsumWi(1,1);
970 covmatrix[3] = invsumWi(0,2);
971 covmatrix[4] = invsumWi(1,2);
972 covmatrix[5] = invsumWi(2,2);
975 Double_t det=GetDeterminant3X3(sum);
979 for(Int_t zz=0;zz<3;zz++){
980 for(Int_t ww=0;ww<3;ww++){
981 for(Int_t kk=0;kk<3;kk++) vett[ww][kk]=sum[ww][kk];
983 for(Int_t kk=0;kk<3;kk++) vett[kk][zz]=dsum[kk];
984 initPos[zz]=GetDeterminant3X3(vett)/det;
988 for(Int_t i=0; i<knacc; i++){
989 Double_t p0[3]={0,0,0},p1[3]={0,0,0};
990 for(Int_t ii=0;ii<3;ii++){
991 p0[ii]=vectP0[i][ii];
992 p1[ii]=vectP1[i][ii];
994 sigma+=GetStrLinMinDist(p0,p1,initPos);
997 if(sigma>0.) {sigma=TMath::Sqrt(sigma);}else{sigma=999;}
1001 AliESDVertex theVert(initPos,covmatrix,99999.,knacc);
1002 theVert.SetDispersion(sigma);
1007 //---------------------------------------------------------------------------
1008 Bool_t AliVertexerTracks::TrackToPoint(AliExternalTrackParam *t,
1009 TMatrixD &ri,TMatrixD &wWi,
1010 Bool_t uUi3by3) const
1013 // Extract from the AliExternalTrackParam the global coordinates ri and covariance matrix
1014 // wWi of the space point that it represents (to be used in VertexFitter())
1018 Double_t rotAngle = t->GetAlpha();
1019 if(rotAngle<0.) rotAngle += 2.*TMath::Pi();
1020 Double_t cosRot = TMath::Cos(rotAngle);
1021 Double_t sinRot = TMath::Sin(rotAngle);
1023 ri(0,0) = t->GetX()*cosRot-t->GetY()*sinRot;
1024 ri(1,0) = t->GetX()*sinRot+t->GetY()*cosRot;
1025 ri(2,0) = t->GetZ();
1030 // matrix to go from global (x,y,z) to local (y,z);
1039 // covariance matrix of local (y,z) - inverted
1041 uUi(0,0) = t->GetSigmaY2();
1042 uUi(0,1) = t->GetSigmaZY();
1043 uUi(1,0) = t->GetSigmaZY();
1044 uUi(1,1) = t->GetSigmaZ2();
1045 //printf(" Ui :\n");
1046 //printf(" %f %f\n",uUi(0,0),uUi(0,1));
1047 //printf(" %f %f\n",uUi(1,0),uUi(1,1));
1049 if(uUi.Determinant() <= 0.) return kFALSE;
1050 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
1052 // weights matrix: wWi = qQiT * uUiInv * qQi
1053 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
1054 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
1057 if(fVert.GetNContributors()<1) AliFatal("Vertex from finder is empty");
1058 // matrix to go from global (x,y,z) to local (x,y,z);
1070 // covariance of fVert along the track
1071 Double_t p[3],pt,ptot;
1073 pt = TMath::Sqrt(p[0]*p[0]+p[1]*p[1]);
1074 ptot = TMath::Sqrt(pt*pt+p[2]*p[2]);
1075 Double_t cphi = p[0]/pt; //cos(phi)=px/pt
1076 Double_t sphi = p[1]/pt; //sin(phi)=py/pt
1077 Double_t clambda = pt/ptot; //cos(lambda)=pt/ptot
1078 Double_t slambda = p[2]/ptot; //sin(lambda)=pz/ptot
1079 Double_t covfVert[6];
1080 fVert.GetCovMatrix(covfVert);
1081 Double_t covfVertalongt =
1082 covfVert[0]*cphi*cphi*clambda*clambda
1083 +covfVert[1]*2.*cphi*sphi*clambda*clambda
1084 +covfVert[3]*2.*cphi*clambda*slambda
1085 +covfVert[2]*sphi*sphi*clambda*clambda
1086 +covfVert[4]*2.*sphi*clambda*slambda
1087 +covfVert[5]*slambda*slambda;
1088 // covariance matrix of local (x,y,z) - inverted
1090 uUi(0,0) = covfVertalongt * fnSigmaForUi00 * fnSigmaForUi00;
1091 if(fDebug) printf("=====> sqrtUi00 cm %f\n",TMath::Sqrt(uUi(0,0)));
1095 uUi(1,1) = t->GetSigmaY2();
1096 uUi(1,2) = t->GetSigmaZY();
1098 uUi(2,1) = t->GetSigmaZY();
1099 uUi(2,2) = t->GetSigmaZ2();
1100 //printf(" Ui :\n");
1101 //printf(" %f %f\n",uUi(0,0),uUi(0,1));
1102 //printf(" %f %f\n",uUi(1,0),uUi(1,1));
1104 if(uUi.Determinant() <= 0.) return kFALSE;
1105 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
1107 // weights matrix: wWi = qQiT * uUiInv * qQi
1108 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
1109 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
1116 //---------------------------------------------------------------------------
1117 void AliVertexerTracks::TooFewTracks()
1120 // When the number of tracks is < fMinTracks,
1121 // deal with vertices not found and prepare to exit
1123 if(fDebug) printf("TooFewTracks\n");
1125 Double_t pos[3],err[3];
1126 pos[0] = fNominalPos[0];
1127 err[0] = TMath::Sqrt(fNominalCov[0]);
1128 pos[1] = fNominalPos[1];
1129 err[1] = TMath::Sqrt(fNominalCov[2]);
1130 pos[2] = fNominalPos[2];
1131 err[2] = TMath::Sqrt(fNominalCov[5]);
1132 Int_t ncontr = (err[0]>1. ? -1 : -3);
1134 fCurrentVertex = new AliESDVertex(pos,err);
1135 fCurrentVertex->SetNContributors(ncontr);
1138 fCurrentVertex->SetTitle("VertexerTracksWithConstraint");
1140 fCurrentVertex->SetTitle("VertexerTracksNoConstraint");
1143 if(!fTrkArraySel.IsEmpty()) fTrkArraySel.Delete();
1144 if(fIdSel) {delete [] fIdSel; fIdSel=NULL;}
1145 if(fTrksToSkip) {delete [] fTrksToSkip; fTrksToSkip=NULL;}
1149 //---------------------------------------------------------------------------
1150 void AliVertexerTracks::VertexFinder(Int_t optUseWeights)
1153 // Get estimate of vertex position in (x,y) from tracks DCA
1155 Double_t initPos[3];
1157 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
1158 Int_t nacc = (Int_t)fTrkArraySel.GetEntriesFast();
1159 Double_t aver[3]={0.,0.,0.};
1160 Double_t aversq[3]={0.,0.,0.};
1161 Double_t sigmasq[3]={0.,0.,0.};
1164 AliExternalTrackParam *track1;
1165 AliExternalTrackParam *track2;
1166 Double_t pos[3],dir[3];
1167 Double_t alpha,mindist;
1169 for(Int_t i=0; i<nacc; i++){
1170 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
1171 alpha=track1->GetAlpha();
1172 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1173 track1->GetXYZAt(mindist,GetFieldkG(),pos);
1174 track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
1175 AliStrLine *line1 = new AliStrLine(pos,dir);
1177 // AliStrLine *line1 = new AliStrLine();
1178 // track1->ApproximateHelixWithLine(mindist,GetFieldkG(),line1);
1180 for(Int_t j=i+1; j<nacc; j++){
1181 track2 = (AliExternalTrackParam*)fTrkArraySel.At(j);
1182 alpha=track2->GetAlpha();
1183 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1184 track2->GetXYZAt(mindist,GetFieldkG(),pos);
1185 track2->GetPxPyPzAt(mindist,GetFieldkG(),dir);
1186 AliStrLine *line2 = new AliStrLine(pos,dir);
1187 // AliStrLine *line2 = new AliStrLine();
1188 // track2->ApproximateHelixWithLine(mindist,GetFieldkG(),line2);
1189 Double_t distCA=line2->GetDCA(line1);
1190 //printf("%d %d %f\n",i,j,distCA);
1191 if(fDCAcut<=0 || (fDCAcut>0&&distCA<fDCAcut)){
1192 Double_t pnt1[3],pnt2[3],crosspoint[3];
1194 if(optUseWeights<=0){
1195 Int_t retcode = line2->Cross(line1,crosspoint);
1198 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
1199 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1202 if(optUseWeights>0){
1203 Int_t retcode = line1->CrossPoints(line2,pnt1,pnt2);
1206 alpha=track1->GetAlpha();
1207 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
1208 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
1209 alpha=track2->GetAlpha();
1210 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
1211 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
1212 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
1213 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
1214 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
1215 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
1216 crosspoint[0]=wx1*pnt1[0] + wx2*pnt2[0];
1217 crosspoint[1]=wy1*pnt1[1] + wy2*pnt2[1];
1218 crosspoint[2]=wz1*pnt1[2] + wz2*pnt2[2];
1221 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
1222 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1231 for(Int_t jj=0;jj<3;jj++){
1232 initPos[jj] = aver[jj]/ncombi;
1233 //printf("%f\n",initPos[jj]);
1235 sigmasq[jj]=aversq[jj]-initPos[jj]*initPos[jj];
1238 sigma=TMath::Sqrt(TMath::Abs(sigma));
1241 Warning("VertexFinder","Finder did not succed");
1244 fVert.SetXYZ(initPos);
1245 fVert.SetDispersion(sigma);
1246 fVert.SetNContributors(ncombi);
1248 //---------------------------------------------------------------------------
1249 void AliVertexerTracks::VertexFitter()
1252 // The optimal estimate of the vertex position is given by a "weighted
1253 // average of tracks positions".
1254 // Original method: V. Karimaki, CMS Note 97/0051
1256 Bool_t useConstraint = fConstraint;
1257 Double_t initPos[3];
1259 fVert.GetXYZ(initPos);
1261 initPos[0]=fNominalPos[0];
1262 initPos[1]=fNominalPos[1];
1263 initPos[2]=fNominalPos[2];
1266 Int_t nTrksSel = (Int_t)fTrkArraySel.GetEntries();
1267 if(nTrksSel==1) useConstraint=kTRUE;
1269 printf("--- VertexFitter(): start\n");
1270 printf(" Number of tracks in array: %d\n",nTrksSel);
1271 printf(" Minimum # tracks required in fit: %d\n",fMinTracks);
1272 printf(" Vertex position after finder: %f,%f,%f\n",initPos[0],initPos[1],initPos[2]);
1273 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]));
1276 // special treatment for few-tracks fits (e.g. secondary vertices)
1277 Bool_t uUi3by3 = kFALSE; if(nTrksSel<5 && !useConstraint) uUi3by3 = kTRUE;
1282 rv(0,0) = initPos[0];
1283 rv(1,0) = initPos[1];
1285 Double_t xlStart,alpha;
1287 Double_t chi2,chi2i,chi2b;
1288 AliExternalTrackParam *t = 0;
1291 // initial vertex covariance matrix
1293 vVb(0,0) = fNominalCov[0];
1294 vVb(0,1) = fNominalCov[1];
1296 vVb(1,0) = fNominalCov[1];
1297 vVb(1,1) = fNominalCov[2];
1301 vVb(2,2) = fNominalCov[5];
1302 TMatrixD vVbInv(TMatrixD::kInverted,vVb);
1304 rb(0,0) = fNominalPos[0];
1305 rb(1,0) = fNominalPos[1];
1306 rb(2,0) = fNominalPos[2];
1307 TMatrixD vVbInvrb(vVbInv,TMatrixD::kMult,rb);
1311 // 1st - estimate of vtx using all tracks
1312 // 2nd - estimate of global chi2
1313 for(step=0; step<2; step++) {
1314 if(fDebug) printf(" step = %d\n",step);
1318 if(step==1) { initPos[0]=rv(0,0); initPos[0]=rv(1,0); }
1320 TMatrixD sumWiri(3,1);
1321 TMatrixD sumWi(3,3);
1322 for(i=0; i<3; i++) {
1324 for(j=0; j<3; j++) sumWi(j,i) = 0.;
1327 // mean vertex constraint
1330 sumWiri(i,0) += vVbInvrb(i,0);
1331 for(k=0;k<3;k++) sumWi(i,k) += vVbInv(i,k);
1334 TMatrixD deltar = rv; deltar -= rb;
1335 TMatrixD vVbInvdeltar(vVbInv,TMatrixD::kMult,deltar);
1336 chi2b = deltar(0,0)*vVbInvdeltar(0,0)+
1337 deltar(1,0)*vVbInvdeltar(1,0)+
1338 deltar(2,0)*vVbInvdeltar(2,0);
1343 for(k=0; k<nTrksSel; k++) {
1344 // get track from track array
1345 t = (AliExternalTrackParam*)fTrkArraySel.At(k);
1346 alpha = t->GetAlpha();
1347 xlStart = initPos[0]*TMath::Cos(alpha)+initPos[1]*TMath::Sin(alpha);
1348 // to vtxSeed (from finder)
1349 t->PropagateTo(xlStart,GetFieldkG());
1351 // vector of track global coordinates
1353 // covariance matrix of ri
1356 // get space point from track
1357 if(!TrackToPoint(t,ri,wWi,uUi3by3)) continue;
1358 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
1361 TMatrixD deltar = rv; deltar -= ri;
1362 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
1363 chi2i = deltar(0,0)*wWideltar(0,0)+
1364 deltar(1,0)*wWideltar(1,0)+
1365 deltar(2,0)*wWideltar(2,0);
1367 // add to total chi2
1374 } // end loop on tracks
1376 if(nTrksUsed < fMinTracks) {
1381 Double_t determinant = sumWi.Determinant();
1382 if(determinant < fMinDetFitter) {
1383 printf("det(V) = %f (<%f)\n",determinant,fMinDetFitter);
1389 // inverted of weights matrix
1390 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
1392 // position of primary vertex
1393 rv.Mult(vV,sumWiri);
1395 } // end loop on the 2 steps
1402 Double_t position[3];
1403 position[0] = rv(0,0);
1404 position[1] = rv(1,0);
1405 position[2] = rv(2,0);
1406 Double_t covmatrix[6];
1407 covmatrix[0] = vV(0,0);
1408 covmatrix[1] = vV(0,1);
1409 covmatrix[2] = vV(1,1);
1410 covmatrix[3] = vV(0,2);
1411 covmatrix[4] = vV(1,2);
1412 covmatrix[5] = vV(2,2);
1414 // for correct chi2/ndf, count constraint as additional "track"
1415 if(fConstraint) nTrksUsed++;
1416 // store data in the vertex object
1417 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nTrksUsed);
1420 printf(" Vertex after fit:\n");
1421 fCurrentVertex->PrintStatus();
1422 printf("--- VertexFitter(): finish\n");
1427 //----------------------------------------------------------------------------
1428 AliESDVertex* AliVertexerTracks::VertexForSelectedTracks(TObjArray *trkArray,
1430 Bool_t optUseFitter,
1431 Bool_t optPropagate)
1434 // Return vertex from tracks (AliExternalTrackParam) in array
1439 // get tracks and propagate them to initial vertex position
1440 fIdSel = new UShort_t[(Int_t)trkArray->GetEntriesFast()];
1441 Int_t nTrksSel = PrepareTracks(*trkArray,id,0);
1442 if(nTrksSel < TMath::Max(2,fMinTracks)) {
1444 return fCurrentVertex;
1449 case 1: StrLinVertexFinderMinDist(1); break;
1450 case 2: StrLinVertexFinderMinDist(0); break;
1451 case 3: HelixVertexFinder(); break;
1452 case 4: VertexFinder(1); break;
1453 case 5: VertexFinder(0); break;
1454 default: printf("Wrong algorithm\n"); break;
1456 if(fDebug) printf(" Vertex finding completed\n");
1462 Double_t position[3]={fVert.GetXv(),fVert.GetYv(),fVert.GetZv()};
1463 Double_t covmatrix[6];
1464 fVert.GetCovMatrix(covmatrix);
1465 Double_t chi2=99999.;
1466 Int_t nTrksUsed=fVert.GetNContributors();
1467 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nTrksUsed);
1469 fCurrentVertex->SetDispersion(fVert.GetDispersion());
1472 // set indices of used tracks and propagate track to found vertex
1473 UShort_t *indices = 0;
1474 Double_t d0z0[2],covd0z0[3];
1475 AliExternalTrackParam *t = 0;
1476 if(fCurrentVertex->GetNContributors()>0) {
1477 indices = new UShort_t[fCurrentVertex->GetNContributors()];
1478 for(Int_t jj=0; jj<(Int_t)fTrkArraySel.GetEntriesFast(); jj++) {
1479 indices[jj] = fIdSel[jj];
1480 t = (AliExternalTrackParam*)fTrkArraySel.At(jj);
1481 if(optPropagate && optUseFitter) {
1482 if(TMath::Sqrt(fCurrentVertex->GetXv()*fCurrentVertex->GetXv()+fCurrentVertex->GetYv()*fCurrentVertex->GetYv())<3.) {
1483 t->PropagateToDCA(fCurrentVertex,GetFieldkG(),100.,d0z0,covd0z0);
1484 if(fDebug) printf("Track %d propagated to found vertex\n",jj);
1486 AliWarning("Found vertex outside beam pipe!");
1490 fCurrentVertex->SetIndices(fCurrentVertex->GetNContributors(),indices);
1494 delete [] indices; indices=NULL;
1495 delete [] fIdSel; fIdSel=NULL;
1496 fTrkArraySel.Delete();
1498 return fCurrentVertex;
1500 //----------------------------------------------------------------------------
1501 AliESDVertex* AliVertexerTracks::VertexForSelectedESDTracks(TObjArray *trkArray,
1502 Bool_t optUseFitter,
1503 Bool_t optPropagate)
1506 // Return vertex from array of ESD tracks
1509 Int_t nTrks = (Int_t)trkArray->GetEntriesFast();
1510 UShort_t *id = new UShort_t[nTrks];
1512 AliESDtrack *esdt = 0;
1513 for(Int_t i=0; i<nTrks; i++){
1514 esdt = (AliESDtrack*)trkArray->At(i);
1515 id[i] = (UShort_t)esdt->GetID();
1518 VertexForSelectedTracks(trkArray,id,optUseFitter,optPropagate);
1520 delete [] id; id=NULL;
1522 return fCurrentVertex;
1524 //--------------------------------------------------------------------------