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 "AliESDEvent.h"
39 #include "AliESDtrack.h"
40 #include "AliVertexerTracks.h"
42 ClassImp(AliVertexerTracks)
45 //----------------------------------------------------------------------------
46 AliVertexerTracks::AliVertexerTracks():
73 // Default constructor
78 //----------------------------------------------------------------------------
79 AliVertexerTracks::AliVertexerTracks(Double_t fieldkG):
106 // Standard constructor
112 //-----------------------------------------------------------------------------
113 AliVertexerTracks::~AliVertexerTracks()
115 // Default Destructor
116 // The objects pointed by the following pointer are not owned
117 // by this class and are not deleted
119 if(fTrksToSkip) { delete [] fTrksToSkip; fTrksToSkip=NULL; }
120 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
122 //----------------------------------------------------------------------------
123 AliESDVertex* AliVertexerTracks::FindPrimaryVertex(const AliESDEvent *esdEvent)
126 // Primary vertex for current ESD event
128 // 1st with 5*fNSigma*sigma cut w.r.t. to initial vertex
129 // + cut on sqrt(d0d0+z0z0) if fConstraint=kFALSE
130 // 2nd with fNSigma*sigma cut w.r.t. to vertex found in 1st iteration)
134 // accept 1-track case only if constraint is available
135 if(!fConstraint && fMinTracks==1) fMinTracks=2;
137 // read tracks from ESD
138 Int_t nTrks = (Int_t)esdEvent->GetNumberOfTracks();
139 if(nTrks<fMinTracks) {
141 return fCurrentVertex;
145 TDirectory * olddir = gDirectory;
147 if(nTrks>500) f = new TFile("VertexerTracks.root","recreate");
148 TObjArray trkArrayOrig(nTrks);
149 UShort_t *idOrig = new UShort_t[nTrks];
152 AliExternalTrackParam *t=0;
153 // loop on ESD tracks
154 for(Int_t i=0; i<nTrks; i++) {
155 AliESDtrack *esdt = esdEvent->GetTrack(i);
156 // check tracks to skip
157 Bool_t skipThis = kFALSE;
158 for(Int_t j=0; j<fNTrksToSkip; j++) {
159 if(esdt->GetID()==fTrksToSkip[j]) {
160 AliDebug(1,Form("skipping track: %d",i));
164 if(skipThis) continue;
166 // check number of clusters in ITS or TPC
167 if(esdt->GetNcls(fMode) < fMinClusters) continue;
169 if(fMode==0) { // ITS mode
170 if(fITSrefit && !(esdt->GetStatus()&AliESDtrack::kITSrefit)) continue;
171 Double_t x,p[5],cov[15];
172 esdt->GetExternalParameters(x,p);
173 esdt->GetExternalCovariance(cov);
174 t = new AliExternalTrackParam(x,esdt->GetAlpha(),p,cov);
175 } else if(fMode==1) { // TPC mode
176 t = (AliExternalTrackParam*)esdt->GetTPCInnerParam();
178 Double_t radius = 2.8; //something less than the beam pipe radius
179 if(!PropagateTrackTo(t,radius)) continue;
181 trkArrayOrig.AddLast(t);
182 idOrig[nTrksOrig]=(UShort_t)esdt->GetID();
184 } // end loop on ESD tracks
186 // call method that will reconstruct the vertex
187 FindPrimaryVertex(&trkArrayOrig,idOrig);
189 if(fMode==0) trkArrayOrig.Delete();
190 delete [] idOrig; idOrig=NULL;
193 f->Close(); delete f; f = NULL;
194 gSystem->Unlink("VertexerTracks.root");
198 return fCurrentVertex;
200 //----------------------------------------------------------------------------
201 AliESDVertex* AliVertexerTracks::FindPrimaryVertex(TObjArray *trkArrayOrig,
205 // Primary vertex using the AliExternalTrackParam's in the TObjArray.
206 // idOrig must contain the track IDs from AliESDtrack::GetID()
208 // 1st with 5*fNSigma*sigma cut w.r.t. to initial vertex
209 // + cut on sqrt(d0d0+z0z0) if fConstraint=kFALSE
210 // 2nd with fNSigma*sigma cut w.r.t. to vertex found in 1st iteration)
214 // accept 1-track case only if constraint is available
215 if(!fConstraint && fMinTracks==1) fMinTracks=2;
217 // read tracks from array
218 Int_t nTrksOrig = (Int_t)trkArrayOrig->GetEntriesFast();
219 AliDebug(1,Form("Initial number of tracks: %d",nTrksOrig));
220 if(nTrksOrig<fMinTracks) {
221 AliDebug(1,"TooFewTracks");
223 return fCurrentVertex;
226 // If fConstraint=kFALSE
227 // run VertexFinder(1) to get rough estimate of initVertex (x,y)
229 // fill fTrkArraySel, for VertexFinder()
230 fIdSel = new UShort_t[nTrksOrig];
231 PrepareTracks(*trkArrayOrig,idOrig,0);
232 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
233 Double_t cutsave = fDCAcut;
234 fDCAcut = fDCAcutIter0;
235 VertexFinder(1); // using weights, cutting dca < fDCAcutIter0
237 if(fVert.GetNContributors()>0) {
238 fVert.GetXYZ(fNominalPos);
239 fNominalPos[0] = fVert.GetXv();
240 fNominalPos[1] = fVert.GetYv();
241 fNominalPos[2] = fVert.GetZv();
242 AliDebug(1,Form("No mean vertex: VertexFinder gives (%f, %f, %f)",fNominalPos[0],fNominalPos[1],fNominalPos[2]));
247 AliDebug(1,"No mean vertex and VertexFinder failed");
254 // propagate tracks to fNominalPos vertex
256 // if(constraint) reject for |d0|>5*fNSigma*sigma w.r.t. fNominal... vertex
257 // else reject for |d0|\oplus|z0| > 5 mm w.r.t. fNominal... vertex
259 // propagate tracks to best between initVertex and fCurrentVertex
260 // preselect tracks (reject for |d0|>fNSigma*sigma w.r.t. best
261 // between initVertex and fCurrentVertex)
262 for(Int_t iter=1; iter<=2; iter++) {
263 if(fOnlyFitter && iter==1) continue;
264 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
265 fIdSel = new UShort_t[nTrksOrig];
266 Int_t nTrksSel = PrepareTracks(*trkArrayOrig,idOrig,iter);
267 AliDebug(1,Form("N tracks selected in iteration %d: %d",iter,nTrksSel));
268 if(nTrksSel < fMinTracks) {
270 return fCurrentVertex;
276 AliDebug(1,"Just one track");
277 OneTrackVertFinder();
280 case 1: StrLinVertexFinderMinDist(1); break;
281 case 2: StrLinVertexFinderMinDist(0); break;
282 case 3: HelixVertexFinder(); break;
283 case 4: VertexFinder(1); break;
284 case 5: VertexFinder(0); break;
285 default: printf("Wrong algorithm"); break;
288 AliDebug(1," Vertex finding completed");
293 } // end loop on the two iterations
296 // set indices of used tracks
297 UShort_t *indices = 0;
298 if(fCurrentVertex->GetNContributors()>0) {
299 Int_t nIndices = (Int_t)fTrkArraySel.GetEntriesFast();
300 indices = new UShort_t[nIndices];
301 for(Int_t jj=0; jj<nIndices; jj++)
302 indices[jj] = fIdSel[jj];
303 fCurrentVertex->SetIndices(nIndices,indices);
305 delete [] indices; indices=NULL;
309 TString title="VertexerTracksNoConstraint";
311 title="VertexerTracksWithConstraint";
312 if(fOnlyFitter) title.Append("OnlyFitter");
314 fCurrentVertex->SetTitle(title.Data());
317 AliDebug(1,Form("xyz: %f %f %f; nc %d",fCurrentVertex->GetXv(),fCurrentVertex->GetYv(),fCurrentVertex->GetZv(),fCurrentVertex->GetNContributors()));
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 AliDebug(1,Form("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 AliDebug(1," PrepareTracks()");
534 Int_t nTrksOrig = (Int_t)trkArrayOrig.GetEntriesFast();
537 Double_t sigmaCurr[3];
538 Double_t normdistx,normdisty;
539 Double_t d0z0[2],covd0z0[3];
542 AliESDVertex *initVertex = new AliESDVertex(fNominalPos,fNominalCov,1,1);
544 if(!fTrkArraySel.IsEmpty()) fTrkArraySel.Delete();
546 AliExternalTrackParam *track=0;
549 for(Int_t i=0; i<nTrksOrig; i++) {
550 track = new AliExternalTrackParam(*(AliExternalTrackParam*)trkArrayOrig.At(i));
552 if(TMath::Abs(track->GetTgl())>fMaxTgl) {
553 AliDebug(1,Form(" rejecting track with tgl = %f",track->GetTgl()));
554 delete track; continue;
557 Bool_t propagateOK = kFALSE;
558 // propagate track to vertex
559 if(optImpParCut<2 || fOnlyFitter) { // optImpParCut==1 or 0
560 propagateOK = 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 propagateOK = track->PropagateToDCA(fCurrentVertex,GetFieldkG(),100.,d0z0,covd0z0);
569 propagateOK = track->PropagateToDCA(initVertex,GetFieldkG(),100.,d0z0,covd0z0);
574 AliDebug(1," rejected");
575 delete track; continue;
578 sigmad0 = TMath::Sqrt(covd0z0[0]);
579 maxd0rphi = fNSigma*sigmad0;
580 if(optImpParCut==1) maxd0rphi *= 5.;
581 maxd0rphi = TMath::Min(maxd0rphi,fFiducialR);
582 //sigmad0z0 = TMath::Sqrt(covd0z0[0]+covd0z0[2]); // for future improvement
583 //maxd0z0 = 10.*fNSigma*sigmad0z0;
585 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));
588 //---- track selection based on impact parameters ----//
590 // always reject tracks outside fiducial volume
591 if(TMath::Abs(d0z0[0])>fFiducialR || TMath::Abs(d0z0[1])>fFiducialZ) {
592 AliDebug(1," rejected");
593 delete track; continue;
596 // during iterations 1 and 2 , reject tracks with d0rphi > maxd0rphi
597 if(optImpParCut>0 && TMath::Abs(d0z0[0])>maxd0rphi) {
598 AliDebug(1," rejected");
599 delete track; continue;
602 // if fConstraint=kFALSE, during iterations 1 and 2 ||
603 // if fConstraint=kTRUE, during iteration 2,
604 // select tracks with d0oplusz0 < fMaxd0z0
605 if((!fConstraint && optImpParCut>0 && fVert.GetNContributors()>0) ||
606 ( fConstraint && optImpParCut==2)) {
608 TMath::Sqrt(d0z0[0]*d0z0[0]+d0z0[1]*d0z0[1])>fMaxd0z0) {
609 AliDebug(1," rejected");
610 delete track; continue;
614 // track passed all selections
615 fTrkArraySel.AddLast(track);
616 fIdSel[nTrksSel] = idOrig[i];
618 } // end loop on tracks
624 //----------------------------------------------------------------------------
625 Bool_t AliVertexerTracks::PropagateTrackTo(AliExternalTrackParam *track,
627 //----------------------------------------------------------------
628 // COPIED from AliTracker
630 // Propagates the track to the plane X=xk (cm).
632 // Origin: Marian Ivanov, Marian.Ivanov@cern.ch
633 //----------------------------------------------------------------
635 const Double_t kEpsilon = 0.00001;
636 Double_t xpos = track->GetX();
637 Double_t dir = (xpos<xToGo) ? 1. : -1.;
638 Double_t maxStep = 5;
639 Double_t maxSnp = 0.8;
641 while ( (xToGo-xpos)*dir > kEpsilon){
642 Double_t step = dir*TMath::Min(TMath::Abs(xToGo-xpos), maxStep);
643 Double_t x = xpos+step;
644 Double_t xyz0[3],xyz1[3];
645 track->GetXYZ(xyz0); //starting global position
647 if(!track->GetXYZAt(x,GetFieldkG(),xyz1)) return kFALSE; // no prolongation
648 xyz1[2]+=kEpsilon; // waiting for bug correction in geo
650 if(TMath::Abs(track->GetSnpAt(x,GetFieldkG())) >= maxSnp) return kFALSE;
651 if(!track->PropagateTo(x,GetFieldkG())) return kFALSE;
653 if(TMath::Abs(track->GetSnp()) >= maxSnp) return kFALSE;
654 track->GetXYZ(xyz0); // global position
655 Double_t alphan = TMath::ATan2(xyz0[1], xyz0[0]);
657 Double_t ca=TMath::Cos(alphan-track->GetAlpha()),
658 sa=TMath::Sin(alphan-track->GetAlpha());
659 Double_t sf=track->GetSnp(), cf=TMath::Sqrt(1.- sf*sf);
660 Double_t sinNew = sf*ca - cf*sa;
661 if(TMath::Abs(sinNew) >= maxSnp) return kFALSE;
662 if(!track->Rotate(alphan)) return kFALSE;
664 xpos = track->GetX();
668 //---------------------------------------------------------------------------
669 AliESDVertex* AliVertexerTracks::RemoveTracksFromVertex(AliESDVertex *inVtx,
675 // Removes tracks in trksTree from fit of inVtx
678 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraint")) {
679 printf("ERROR: primary vertex has no constraint: cannot remove tracks");
682 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraintOnlyFitter"))
683 printf("WARNING: result of tracks' removal will be only approximately correct");
686 rv(0,0) = inVtx->GetXv();
687 rv(1,0) = inVtx->GetYv();
688 rv(2,0) = inVtx->GetZv();
691 inVtx->GetCovMatrix(cov);
693 vV(0,1) = cov[1]; vV(1,0) = cov[1];
695 vV(0,2) = cov[3]; vV(2,0) = cov[3];
696 vV(1,2) = cov[4]; vV(2,1) = cov[4];
699 TMatrixD sumWi(TMatrixD::kInverted,vV);
700 TMatrixD sumWiri(sumWi,TMatrixD::kMult,rv);
702 Int_t nUsedTrks = inVtx->GetNIndices();
703 Double_t chi2 = inVtx->GetChi2();
705 AliExternalTrackParam *track = 0;
706 Int_t ntrks = (Int_t)trkArray->GetEntriesFast();
707 for(Int_t i=0;i<ntrks;i++) {
708 track = (AliExternalTrackParam*)trkArray->At(i);
709 if(!inVtx->UsesTrack(id[i])) {
710 printf("track %d was not used in vertex fit",id[i]);
713 Double_t alpha = track->GetAlpha();
714 Double_t xl = diamondxy[0]*TMath::Cos(alpha)+diamondxy[1]*TMath::Sin(alpha);
715 track->PropagateTo(xl,GetFieldkG());
716 // vector of track global coordinates
718 // covariance matrix of ri
721 // get space point from track
722 if(!TrackToPoint(track,ri,wWi)) continue;
724 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
730 TMatrixD deltar = rv; deltar -= ri;
731 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
732 Double_t chi2i = deltar(0,0)*wWideltar(0,0)+
733 deltar(1,0)*wWideltar(1,0)+
734 deltar(2,0)*wWideltar(2,0);
735 // remove from total chi2
740 printf("Trying to remove too many tracks!");
748 // new inverted of weights matrix
749 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
751 // new position of primary vertex
752 rvnew.Mult(vVnew,sumWiri);
754 Double_t position[3];
755 position[0] = rvnew(0,0);
756 position[1] = rvnew(1,0);
757 position[2] = rvnew(2,0);
765 // store data in the vertex object
766 AliESDVertex *outVtx = new AliESDVertex(position,cov,chi2,nUsedTrks);
767 outVtx->SetTitle(inVtx->GetTitle());
768 UShort_t *inindices = inVtx->GetIndices();
769 Int_t nIndices = nUsedTrks;
770 UShort_t *outindices = new UShort_t[nIndices];
772 for(Int_t k=0; k<inVtx->GetNIndices(); k++) {
773 Bool_t copyindex=kTRUE;
774 for(Int_t l=0; l<ntrks; l++) {
775 if(inindices[k]==id[l]) copyindex=kFALSE;
778 outindices[j] = inindices[k]; j++;
781 outVtx->SetIndices(nIndices,outindices);
782 delete [] outindices;
785 printf("Vertex before removing tracks:");
786 inVtx->PrintStatus();
787 inVtx->PrintIndices();
788 printf("Vertex after removing tracks:");
789 outVtx->PrintStatus();
790 outVtx->PrintIndices();
795 //---------------------------------------------------------------------------
796 void AliVertexerTracks::SetCuts(Double_t *cuts)
802 SetDCAcutIter0(cuts[1]);
804 if(fMode==0 && cuts[3]<0) SetITSrefitNotRequired();
805 SetMinClusters((Int_t)(TMath::Abs(cuts[3])));
806 SetMinTracks((Int_t)(cuts[4]));
807 SetNSigmad0(cuts[5]);
808 SetMinDetFitter(cuts[6]);
810 SetFiducialRZ(cuts[8],cuts[9]);
814 //---------------------------------------------------------------------------
815 void AliVertexerTracks::SetITSMode(Double_t dcacut,
816 Double_t dcacutIter0,
821 Double_t mindetfitter,
827 // Cut values for ITS mode
831 SetITSrefitRequired();
833 SetITSrefitNotRequired();
836 SetDCAcutIter0(dcacutIter0);
838 SetMinClusters(TMath::Abs(minCls));
839 SetMinTracks(mintrks);
841 SetMinDetFitter(mindetfitter);
843 SetFiducialRZ(fidR,fidZ);
847 //---------------------------------------------------------------------------
848 void AliVertexerTracks::SetTPCMode(Double_t dcacut,
849 Double_t dcacutIter0,
854 Double_t mindetfitter,
860 // Cut values for TPC mode
863 SetITSrefitNotRequired();
865 SetDCAcutIter0(dcacutIter0);
867 SetMinClusters(minCls);
868 SetMinTracks(mintrks);
870 SetMinDetFitter(mindetfitter);
872 SetFiducialRZ(fidR,fidZ);
876 //---------------------------------------------------------------------------
877 void AliVertexerTracks::SetSkipTracks(Int_t n,Int_t *skipped)
880 // Mark the tracks not to be used in the vertex reconstruction.
881 // Tracks are identified by AliESDtrack::GetID()
883 fNTrksToSkip = n; fTrksToSkip = new Int_t[n];
884 for(Int_t i=0;i<n;i++) fTrksToSkip[i] = skipped[i];
887 //---------------------------------------------------------------------------
888 void AliVertexerTracks::SetVtxStart(AliESDVertex *vtx)
891 // Set initial vertex knowledge
893 vtx->GetXYZ(fNominalPos);
894 vtx->GetCovMatrix(fNominalCov);
898 //---------------------------------------------------------------------------
899 void AliVertexerTracks::StrLinVertexFinderMinDist(Int_t optUseWeights)
901 AliExternalTrackParam *track1;
902 const Int_t knacc = (Int_t)fTrkArraySel.GetEntriesFast();
903 static TClonesArray linarray("AliStrLine",knacc);
904 for(Int_t i=0; i<knacc; i++){
905 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
906 Double_t alpha=track1->GetAlpha();
907 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
908 Double_t pos[3],dir[3],sigmasq[3];
909 track1->GetXYZAt(mindist,GetFieldkG(),pos);
910 track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
911 sigmasq[0]=TMath::Sin(alpha)*TMath::Sin(alpha)*track1->GetSigmaY2();
912 sigmasq[1]=TMath::Cos(alpha)*TMath::Cos(alpha)*track1->GetSigmaY2();
913 sigmasq[2]=track1->GetSigmaZ2();
916 if(!TrackToPoint(track1,ri,wWi)) continue;
919 for(Int_t ia=0;ia<3;ia++){
920 for(Int_t ib=0;ib<3;ib++){
921 wmat[iel]=wWi(ia,ib);
925 new(linarray[i]) AliStrLine(pos,sigmasq,wmat,dir);
927 fVert=TrackletVertexFinder(&linarray,optUseWeights);
930 //---------------------------------------------------------------------------
931 AliESDVertex AliVertexerTracks::TrackletVertexFinder(TClonesArray *lines, Int_t optUseWeights)
933 // Calculate the point at minimum distance to prepared tracks
935 const Int_t knacc = (Int_t)lines->GetEntriesFast();
936 Double_t initPos[3]={0.,0.,0.};
938 Double_t (*vectP0)[3]=new Double_t [knacc][3];
939 Double_t (*vectP1)[3]=new Double_t [knacc][3];
942 Double_t dsum[3]={0,0,0};
944 for(Int_t i=0;i<3;i++){
945 for(Int_t j=0;j<3;j++){
951 for(Int_t i=0; i<knacc; i++){
952 AliStrLine* line1 = (AliStrLine*)lines->At(i);
953 Double_t p0[3],cd[3],sigmasq[3];
957 line1->GetSigma2P0(sigmasq);
958 line1->GetWMatrix(wmat);
961 for(Int_t ia=0;ia<3;ia++){
962 for(Int_t ib=0;ib<3;ib++){
963 wWi(ia,ib)=wmat[iel];
970 Double_t p1[3]={p0[0]+cd[0],p0[1]+cd[1],p0[2]+cd[2]};
980 if(optUseWeights==0)GetStrLinDerivMatrix(p0,p1,matr,dknow);
981 else GetStrLinDerivMatrix(p0,p1,sigmasq,matr,dknow);
984 for(Int_t iii=0;iii<3;iii++){
985 dsum[iii]+=dknow[iii];
986 for(Int_t lj=0;lj<3;lj++) sum[iii][lj]+=matr[iii][lj];
990 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
991 Double_t covmatrix[6];
992 covmatrix[0] = invsumWi(0,0);
993 covmatrix[1] = invsumWi(0,1);
994 covmatrix[2] = invsumWi(1,1);
995 covmatrix[3] = invsumWi(0,2);
996 covmatrix[4] = invsumWi(1,2);
997 covmatrix[5] = invsumWi(2,2);
1000 Double_t det=GetDeterminant3X3(sum);
1004 for(Int_t zz=0;zz<3;zz++){
1005 for(Int_t ww=0;ww<3;ww++){
1006 for(Int_t kk=0;kk<3;kk++) vett[ww][kk]=sum[ww][kk];
1008 for(Int_t kk=0;kk<3;kk++) vett[kk][zz]=dsum[kk];
1009 initPos[zz]=GetDeterminant3X3(vett)/det;
1013 for(Int_t i=0; i<knacc; i++){
1014 Double_t p0[3]={0,0,0},p1[3]={0,0,0};
1015 for(Int_t ii=0;ii<3;ii++){
1016 p0[ii]=vectP0[i][ii];
1017 p1[ii]=vectP1[i][ii];
1019 sigma+=GetStrLinMinDist(p0,p1,initPos);
1022 if(sigma>0.) {sigma=TMath::Sqrt(sigma);}else{sigma=999;}
1026 AliESDVertex theVert(initPos,covmatrix,99999.,knacc);
1027 theVert.SetDispersion(sigma);
1032 //---------------------------------------------------------------------------
1033 Bool_t AliVertexerTracks::TrackToPoint(AliExternalTrackParam *t,
1034 TMatrixD &ri,TMatrixD &wWi,
1035 Bool_t uUi3by3) const
1038 // Extract from the AliExternalTrackParam the global coordinates ri and covariance matrix
1039 // wWi of the space point that it represents (to be used in VertexFitter())
1043 Double_t rotAngle = t->GetAlpha();
1044 if(rotAngle<0.) rotAngle += 2.*TMath::Pi();
1045 Double_t cosRot = TMath::Cos(rotAngle);
1046 Double_t sinRot = TMath::Sin(rotAngle);
1048 ri(0,0) = t->GetX()*cosRot-t->GetY()*sinRot;
1049 ri(1,0) = t->GetX()*sinRot+t->GetY()*cosRot;
1050 ri(2,0) = t->GetZ();
1055 // matrix to go from global (x,y,z) to local (y,z);
1064 // covariance matrix of local (y,z) - inverted
1066 uUi(0,0) = t->GetSigmaY2();
1067 uUi(0,1) = t->GetSigmaZY();
1068 uUi(1,0) = t->GetSigmaZY();
1069 uUi(1,1) = t->GetSigmaZ2();
1071 //printf(" %f %f",uUi(0,0),uUi(0,1));
1072 //printf(" %f %f",uUi(1,0),uUi(1,1));
1074 if(uUi.Determinant() <= 0.) return kFALSE;
1075 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
1077 // weights matrix: wWi = qQiT * uUiInv * qQi
1078 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
1079 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
1082 if(fVert.GetNContributors()<1) AliFatal("Vertex from finder is empty");
1083 // matrix to go from global (x,y,z) to local (x,y,z);
1095 // covariance of fVert along the track
1096 Double_t p[3],pt,ptot;
1098 pt = TMath::Sqrt(p[0]*p[0]+p[1]*p[1]);
1099 ptot = TMath::Sqrt(pt*pt+p[2]*p[2]);
1100 Double_t cphi = p[0]/pt; //cos(phi)=px/pt
1101 Double_t sphi = p[1]/pt; //sin(phi)=py/pt
1102 Double_t clambda = pt/ptot; //cos(lambda)=pt/ptot
1103 Double_t slambda = p[2]/ptot; //sin(lambda)=pz/ptot
1104 Double_t covfVert[6];
1105 fVert.GetCovMatrix(covfVert);
1106 Double_t covfVertalongt =
1107 covfVert[0]*cphi*cphi*clambda*clambda
1108 +covfVert[1]*2.*cphi*sphi*clambda*clambda
1109 +covfVert[3]*2.*cphi*clambda*slambda
1110 +covfVert[2]*sphi*sphi*clambda*clambda
1111 +covfVert[4]*2.*sphi*clambda*slambda
1112 +covfVert[5]*slambda*slambda;
1113 // covariance matrix of local (x,y,z) - inverted
1115 uUi(0,0) = covfVertalongt * fnSigmaForUi00 * fnSigmaForUi00;
1116 AliDebug(1,Form("=====> sqrtUi00 cm %f",TMath::Sqrt(uUi(0,0))));
1120 uUi(1,1) = t->GetSigmaY2();
1121 uUi(1,2) = t->GetSigmaZY();
1123 uUi(2,1) = t->GetSigmaZY();
1124 uUi(2,2) = t->GetSigmaZ2();
1125 //printf(" Ui :\n");
1126 //printf(" %f %f\n",uUi(0,0),uUi(0,1));
1127 //printf(" %f %f\n",uUi(1,0),uUi(1,1));
1129 if(uUi.Determinant() <= 0.) return kFALSE;
1130 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
1132 // weights matrix: wWi = qQiT * uUiInv * qQi
1133 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
1134 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
1141 //---------------------------------------------------------------------------
1142 void AliVertexerTracks::TooFewTracks()
1145 // When the number of tracks is < fMinTracks,
1146 // deal with vertices not found and prepare to exit
1148 AliDebug(1,"TooFewTracks");
1150 Double_t pos[3],err[3];
1151 pos[0] = fNominalPos[0];
1152 err[0] = TMath::Sqrt(fNominalCov[0]);
1153 pos[1] = fNominalPos[1];
1154 err[1] = TMath::Sqrt(fNominalCov[2]);
1155 pos[2] = fNominalPos[2];
1156 err[2] = TMath::Sqrt(fNominalCov[5]);
1157 Int_t ncontr = (err[0]>1. ? -1 : -3);
1158 if(fCurrentVertex) { delete fCurrentVertex; fCurrentVertex=0; }
1159 fCurrentVertex = new AliESDVertex(pos,err);
1160 fCurrentVertex->SetNContributors(ncontr);
1163 fCurrentVertex->SetTitle("VertexerTracksWithConstraint");
1165 fCurrentVertex->SetTitle("VertexerTracksNoConstraint");
1168 if(!fTrkArraySel.IsEmpty()) fTrkArraySel.Delete();
1169 if(fIdSel) {delete [] fIdSel; fIdSel=NULL;}
1170 if(fTrksToSkip) {delete [] fTrksToSkip; fTrksToSkip=NULL;}
1174 //---------------------------------------------------------------------------
1175 void AliVertexerTracks::VertexFinder(Int_t optUseWeights)
1178 // Get estimate of vertex position in (x,y) from tracks DCA
1180 Double_t initPos[3];
1182 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
1183 Int_t nacc = (Int_t)fTrkArraySel.GetEntriesFast();
1184 Double_t aver[3]={0.,0.,0.};
1185 Double_t aversq[3]={0.,0.,0.};
1186 Double_t sigmasq[3]={0.,0.,0.};
1189 AliExternalTrackParam *track1;
1190 AliExternalTrackParam *track2;
1191 Double_t pos[3],dir[3];
1192 Double_t alpha,mindist;
1194 for(Int_t i=0; i<nacc; i++){
1195 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
1196 alpha=track1->GetAlpha();
1197 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1198 track1->GetXYZAt(mindist,GetFieldkG(),pos);
1199 track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
1200 AliStrLine *line1 = new AliStrLine(pos,dir);
1202 // AliStrLine *line1 = new AliStrLine();
1203 // track1->ApproximateHelixWithLine(mindist,GetFieldkG(),line1);
1205 for(Int_t j=i+1; j<nacc; j++){
1206 track2 = (AliExternalTrackParam*)fTrkArraySel.At(j);
1207 alpha=track2->GetAlpha();
1208 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1209 track2->GetXYZAt(mindist,GetFieldkG(),pos);
1210 track2->GetPxPyPzAt(mindist,GetFieldkG(),dir);
1211 AliStrLine *line2 = new AliStrLine(pos,dir);
1212 // AliStrLine *line2 = new AliStrLine();
1213 // track2->ApproximateHelixWithLine(mindist,GetFieldkG(),line2);
1214 Double_t distCA=line2->GetDCA(line1);
1215 //printf("%d %d %f\n",i,j,distCA);
1216 if(fDCAcut<=0 || (fDCAcut>0&&distCA<fDCAcut)){
1217 Double_t pnt1[3],pnt2[3],crosspoint[3];
1219 if(optUseWeights<=0){
1220 Int_t retcode = line2->Cross(line1,crosspoint);
1223 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
1224 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1227 if(optUseWeights>0){
1228 Int_t retcode = line1->CrossPoints(line2,pnt1,pnt2);
1231 alpha=track1->GetAlpha();
1232 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
1233 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
1234 alpha=track2->GetAlpha();
1235 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
1236 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
1237 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
1238 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
1239 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
1240 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
1241 crosspoint[0]=wx1*pnt1[0] + wx2*pnt2[0];
1242 crosspoint[1]=wy1*pnt1[1] + wy2*pnt2[1];
1243 crosspoint[2]=wz1*pnt1[2] + wz2*pnt2[2];
1246 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
1247 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1256 for(Int_t jj=0;jj<3;jj++){
1257 initPos[jj] = aver[jj]/ncombi;
1258 //printf("%f\n",initPos[jj]);
1260 sigmasq[jj]=aversq[jj]-initPos[jj]*initPos[jj];
1263 sigma=TMath::Sqrt(TMath::Abs(sigma));
1266 Warning("VertexFinder","Finder did not succed");
1269 fVert.SetXYZ(initPos);
1270 fVert.SetDispersion(sigma);
1271 fVert.SetNContributors(ncombi);
1273 //---------------------------------------------------------------------------
1274 void AliVertexerTracks::VertexFitter()
1277 // The optimal estimate of the vertex position is given by a "weighted
1278 // average of tracks positions".
1279 // Original method: V. Karimaki, CMS Note 97/0051
1281 Bool_t useConstraint = fConstraint;
1282 Double_t initPos[3];
1284 fVert.GetXYZ(initPos);
1286 initPos[0]=fNominalPos[0];
1287 initPos[1]=fNominalPos[1];
1288 initPos[2]=fNominalPos[2];
1291 Int_t nTrksSel = (Int_t)fTrkArraySel.GetEntries();
1292 if(nTrksSel==1) useConstraint=kTRUE;
1293 AliDebug(1,"--- VertexFitter(): start");
1294 AliDebug(1,Form(" Number of tracks in array: %d\n",nTrksSel));
1295 AliDebug(1,Form(" Minimum # tracks required in fit: %d\n",fMinTracks));
1296 AliDebug(1,Form(" Vertex position after finder: %f,%f,%f\n",initPos[0],initPos[1],initPos[2]));
1297 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])));
1299 // special treatment for few-tracks fits (e.g. secondary vertices)
1300 Bool_t uUi3by3 = kFALSE; if(nTrksSel<5 && !useConstraint) uUi3by3 = kTRUE;
1305 rv(0,0) = initPos[0];
1306 rv(1,0) = initPos[1];
1308 Double_t xlStart,alpha;
1310 Double_t chi2,chi2i,chi2b;
1311 AliExternalTrackParam *t = 0;
1314 // initial vertex covariance matrix
1316 vVb(0,0) = fNominalCov[0];
1317 vVb(0,1) = fNominalCov[1];
1319 vVb(1,0) = fNominalCov[1];
1320 vVb(1,1) = fNominalCov[2];
1324 vVb(2,2) = fNominalCov[5];
1325 TMatrixD vVbInv(TMatrixD::kInverted,vVb);
1327 rb(0,0) = fNominalPos[0];
1328 rb(1,0) = fNominalPos[1];
1329 rb(2,0) = fNominalPos[2];
1330 TMatrixD vVbInvrb(vVbInv,TMatrixD::kMult,rb);
1334 // 1st - estimate of vtx using all tracks
1335 // 2nd - estimate of global chi2
1336 for(step=0; step<2; step++) {
1337 AliDebug(1,Form(" step = %d\n",step));
1341 if(step==1) { initPos[0]=rv(0,0); initPos[0]=rv(1,0); }
1343 TMatrixD sumWiri(3,1);
1344 TMatrixD sumWi(3,3);
1345 for(i=0; i<3; i++) {
1347 for(j=0; j<3; j++) sumWi(j,i) = 0.;
1350 // mean vertex constraint
1353 sumWiri(i,0) += vVbInvrb(i,0);
1354 for(k=0;k<3;k++) sumWi(i,k) += vVbInv(i,k);
1357 TMatrixD deltar = rv; deltar -= rb;
1358 TMatrixD vVbInvdeltar(vVbInv,TMatrixD::kMult,deltar);
1359 chi2b = deltar(0,0)*vVbInvdeltar(0,0)+
1360 deltar(1,0)*vVbInvdeltar(1,0)+
1361 deltar(2,0)*vVbInvdeltar(2,0);
1366 for(k=0; k<nTrksSel; k++) {
1367 // get track from track array
1368 t = (AliExternalTrackParam*)fTrkArraySel.At(k);
1369 alpha = t->GetAlpha();
1370 xlStart = initPos[0]*TMath::Cos(alpha)+initPos[1]*TMath::Sin(alpha);
1371 // to vtxSeed (from finder)
1372 t->PropagateTo(xlStart,GetFieldkG());
1374 // vector of track global coordinates
1376 // covariance matrix of ri
1379 // get space point from track
1380 if(!TrackToPoint(t,ri,wWi,uUi3by3)) continue;
1381 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
1384 TMatrixD deltar = rv; deltar -= ri;
1385 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
1386 chi2i = deltar(0,0)*wWideltar(0,0)+
1387 deltar(1,0)*wWideltar(1,0)+
1388 deltar(2,0)*wWideltar(2,0);
1390 // add to total chi2
1397 } // end loop on tracks
1399 if(nTrksUsed < fMinTracks) {
1404 Double_t determinant = sumWi.Determinant();
1405 if(determinant < fMinDetFitter) {
1406 AliDebug(1,Form("det(V) = %f (<%f)\n",determinant,fMinDetFitter));
1412 // inverted of weights matrix
1413 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
1415 // position of primary vertex
1416 rv.Mult(vV,sumWiri);
1418 } // end loop on the 2 steps
1425 Double_t position[3];
1426 position[0] = rv(0,0);
1427 position[1] = rv(1,0);
1428 position[2] = rv(2,0);
1429 Double_t covmatrix[6];
1430 covmatrix[0] = vV(0,0);
1431 covmatrix[1] = vV(0,1);
1432 covmatrix[2] = vV(1,1);
1433 covmatrix[3] = vV(0,2);
1434 covmatrix[4] = vV(1,2);
1435 covmatrix[5] = vV(2,2);
1437 // for correct chi2/ndf, count constraint as additional "track"
1438 if(fConstraint) nTrksUsed++;
1439 // store data in the vertex object
1440 if(fCurrentVertex) { delete fCurrentVertex; fCurrentVertex=0; }
1441 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nTrksUsed);
1443 AliDebug(1," Vertex after fit:");
1444 AliDebug(1,Form("xyz: %f %f %f; nc %d",fCurrentVertex->GetXv(),fCurrentVertex->GetYv(),fCurrentVertex->GetZv(),fCurrentVertex->GetNContributors()));
1445 AliDebug(1,"--- VertexFitter(): finish\n");
1450 //----------------------------------------------------------------------------
1451 AliESDVertex* AliVertexerTracks::VertexForSelectedTracks(TObjArray *trkArray,
1453 Bool_t optUseFitter,
1454 Bool_t optPropagate)
1457 // Return vertex from tracks (AliExternalTrackParam) in array
1462 // get tracks and propagate them to initial vertex position
1463 fIdSel = new UShort_t[(Int_t)trkArray->GetEntriesFast()];
1464 Int_t nTrksSel = PrepareTracks(*trkArray,id,0);
1465 if(nTrksSel < TMath::Max(2,fMinTracks)) {
1467 return fCurrentVertex;
1472 case 1: StrLinVertexFinderMinDist(1); break;
1473 case 2: StrLinVertexFinderMinDist(0); break;
1474 case 3: HelixVertexFinder(); break;
1475 case 4: VertexFinder(1); break;
1476 case 5: VertexFinder(0); break;
1477 default: printf("Wrong algorithm\n"); break;
1479 AliDebug(1," Vertex finding completed\n");
1485 Double_t position[3]={fVert.GetXv(),fVert.GetYv(),fVert.GetZv()};
1486 Double_t covmatrix[6];
1487 fVert.GetCovMatrix(covmatrix);
1488 Double_t chi2=99999.;
1489 Int_t nTrksUsed=fVert.GetNContributors();
1490 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nTrksUsed);
1492 fCurrentVertex->SetDispersion(fVert.GetDispersion());
1495 // set indices of used tracks and propagate track to found vertex
1496 UShort_t *indices = 0;
1497 Double_t d0z0[2],covd0z0[3];
1498 AliExternalTrackParam *t = 0;
1499 if(fCurrentVertex->GetNContributors()>0) {
1500 indices = new UShort_t[fCurrentVertex->GetNContributors()];
1501 for(Int_t jj=0; jj<(Int_t)fTrkArraySel.GetEntriesFast(); jj++) {
1502 indices[jj] = fIdSel[jj];
1503 t = (AliExternalTrackParam*)fTrkArraySel.At(jj);
1504 if(optPropagate && optUseFitter) {
1505 if(TMath::Sqrt(fCurrentVertex->GetXv()*fCurrentVertex->GetXv()+fCurrentVertex->GetYv()*fCurrentVertex->GetYv())<3.) {
1506 t->PropagateToDCA(fCurrentVertex,GetFieldkG(),100.,d0z0,covd0z0);
1507 AliDebug(1,Form("Track %d propagated to found vertex",jj));
1509 AliWarning("Found vertex outside beam pipe!");
1513 fCurrentVertex->SetIndices(fCurrentVertex->GetNContributors(),indices);
1517 delete [] indices; indices=NULL;
1518 delete [] fIdSel; fIdSel=NULL;
1519 fTrkArraySel.Delete();
1521 return fCurrentVertex;
1523 //----------------------------------------------------------------------------
1524 AliESDVertex* AliVertexerTracks::VertexForSelectedESDTracks(TObjArray *trkArray,
1525 Bool_t optUseFitter,
1526 Bool_t optPropagate)
1529 // Return vertex from array of ESD tracks
1532 Int_t nTrks = (Int_t)trkArray->GetEntriesFast();
1533 UShort_t *id = new UShort_t[nTrks];
1535 AliESDtrack *esdt = 0;
1536 for(Int_t i=0; i<nTrks; i++){
1537 esdt = (AliESDtrack*)trkArray->At(i);
1538 id[i] = (UShort_t)esdt->GetID();
1541 VertexForSelectedTracks(trkArray,id,optUseFitter,optPropagate);
1543 delete [] id; id=NULL;
1545 return fCurrentVertex;
1547 //--------------------------------------------------------------------------