1 /**************************************************************************
2 * Copyright(c) 1998-2003, ALICE Experiment at CERN, All rights reserved. *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
7 * Permission to use, copy, modify and distribute this software and its *
8 * documentation strictly for non-commercial purposes is hereby granted *
9 * without fee, provided that the above copyright notice appears in all *
10 * copies and that both the copyright notice and this permission notice *
11 * appear in the supporting documentation. The authors make no claims *
12 * about the suitability of this software for any purpose. It is *
13 * provided "as is" without express or implied warranty. *
14 **************************************************************************/
16 //-----------------------------------------------------------------
17 // Implementation of the vertexer from tracks
19 // Origin: AliITSVertexerTracks
21 // andrea.dainese@pd.infn.it
23 // massimo.masera@to.infn.it
24 // Moved to STEER and adapted to ESD tracks:
25 // F.Prino, Torino, prino@to.infn.it
26 //-----------------------------------------------------------------
28 //---- Root headers --------
30 #include <TDirectory.h>
34 //---- AliRoot headers -----
36 #include "AliStrLine.h"
37 #include "AliExternalTrackParam.h"
38 #include "AliNeutralTrackParam.h"
39 #include "AliVEvent.h"
40 #include "AliVTrack.h"
41 #include "AliESDEvent.h"
42 #include "AliESDtrack.h"
43 #include "AliVertexerTracks.h"
45 ClassImp(AliVertexerTracks)
48 //----------------------------------------------------------------------------
49 AliVertexerTracks::AliVertexerTracks():
77 // Default constructor
82 //----------------------------------------------------------------------------
83 AliVertexerTracks::AliVertexerTracks(Double_t fieldkG):
111 // Standard constructor
116 //-----------------------------------------------------------------------------
117 AliVertexerTracks::~AliVertexerTracks()
119 // Default Destructor
120 // The objects pointed by the following pointer are not owned
121 // by this class and are not deleted
123 if(fTrksToSkip) { delete [] fTrksToSkip; fTrksToSkip=NULL; }
124 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
126 //----------------------------------------------------------------------------
127 AliESDVertex* AliVertexerTracks::FindPrimaryVertex(const AliVEvent *vEvent)
130 // Primary vertex for current ESD or AOD event
132 // 1st with 5*fNSigma*sigma cut w.r.t. to initial vertex
133 // + cut on sqrt(d0d0+z0z0) if fConstraint=kFALSE
134 // 2nd with fNSigma*sigma cut w.r.t. to vertex found in 1st iteration)
138 TString evtype = vEvent->IsA()->GetName();
139 Bool_t inputAOD = ((evtype=="AliAODEvent") ? kTRUE : kFALSE);
141 if(inputAOD && fMode==1) {
142 printf("Error : AliVertexerTracks: no TPC-only vertex from AOD\n");
144 return fCurrentVertex;
147 // accept 1-track case only if constraint is available
148 if(!fConstraint && fMinTracks==1) fMinTracks=2;
150 // read tracks from AlivEvent
151 Int_t nTrks = (Int_t)vEvent->GetNumberOfTracks();
152 if(nTrks<fMinTracks) {
154 return fCurrentVertex;
158 TDirectory * olddir = gDirectory;
160 if(nTrks>500) f = new TFile("VertexerTracks.root","recreate");
161 TObjArray trkArrayOrig(nTrks);
162 UShort_t *idOrig = new UShort_t[nTrks];
165 AliExternalTrackParam *t=0;
167 for(Int_t i=0; i<nTrks; i++) {
168 AliVTrack *track = (AliVTrack*)vEvent->GetTrack(i);
169 // check tracks to skip
170 Bool_t skipThis = kFALSE;
171 for(Int_t j=0; j<fNTrksToSkip; j++) {
172 if(track->GetID()==fTrksToSkip[j]) {
173 AliDebug(1,Form("skipping track: %d",i));
177 if(skipThis) continue;
179 if(!inputAOD) { // ESD
180 AliESDtrack* esdt = (AliESDtrack*)track;
181 if(esdt->GetNcls(fMode) < fMinClusters) continue;
182 if(fMode==0) { // ITS mode
183 if(fITSrefit && !(esdt->GetStatus()&AliESDtrack::kITSrefit)) continue;
184 Double_t x,p[5],cov[15];
185 esdt->GetExternalParameters(x,p);
186 esdt->GetExternalCovariance(cov);
187 t = new AliExternalTrackParam(x,esdt->GetAlpha(),p,cov);
188 } else if(fMode==1) { // TPC mode
189 t = (AliExternalTrackParam*)esdt->GetTPCInnerParam();
191 Double_t radius = 2.8; //something less than the beam pipe radius
192 if(!PropagateTrackTo(t,radius)) continue;
194 } else { // AOD (only ITS mode)
196 for(Int_t l=0;l<6;l++) if(TESTBIT(track->GetITSClusterMap(),l)) ncls0++;
197 if(ncls0 < fMinClusters) continue;
198 t = new AliExternalTrackParam(track);
200 trkArrayOrig.AddLast(t);
201 idOrig[nTrksOrig]=(UShort_t)track->GetID();
203 } // end loop on tracks
205 // call method that will reconstruct the vertex
206 FindPrimaryVertex(&trkArrayOrig,idOrig);
208 if(fMode==0) trkArrayOrig.Delete();
209 delete [] idOrig; idOrig=NULL;
212 f->Close(); delete f; f = NULL;
213 gSystem->Unlink("VertexerTracks.root");
217 return fCurrentVertex;
219 //----------------------------------------------------------------------------
220 AliESDVertex* AliVertexerTracks::FindPrimaryVertex(TObjArray *trkArrayOrig,
224 // Primary vertex using the AliExternalTrackParam's in the TObjArray.
225 // idOrig must contain the track IDs from AliESDtrack::GetID()
227 // 1st with 5*fNSigma*sigma cut w.r.t. to initial vertex
228 // + cut on sqrt(d0d0+z0z0) if fConstraint=kFALSE
229 // 2nd with fNSigma*sigma cut w.r.t. to vertex found in 1st iteration)
233 // accept 1-track case only if constraint is available
234 if(!fConstraint && fMinTracks==1) fMinTracks=2;
236 // read tracks from array
237 Int_t nTrksOrig = (Int_t)trkArrayOrig->GetEntriesFast();
238 AliDebug(1,Form("Initial number of tracks: %d",nTrksOrig));
239 if(nTrksOrig<fMinTracks) {
240 AliDebug(1,"TooFewTracks");
242 return fCurrentVertex;
245 // If fConstraint=kFALSE
246 // run VertexFinder(1) to get rough estimate of initVertex (x,y)
248 // fill fTrkArraySel, for VertexFinder()
249 fIdSel = new UShort_t[nTrksOrig];
250 PrepareTracks(*trkArrayOrig,idOrig,0);
251 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
252 Double_t cutsave = fDCAcut;
253 fDCAcut = fDCAcutIter0;
255 switch (fAlgoIter0) {
256 case 1: StrLinVertexFinderMinDist(1); break;
257 case 2: StrLinVertexFinderMinDist(0); break;
258 case 3: HelixVertexFinder(); break;
259 case 4: VertexFinder(1); break;
260 case 5: VertexFinder(0); break;
261 default: printf("Wrong algorithm\n"); break;
264 if(fVert.GetNContributors()>0) {
265 fVert.GetXYZ(fNominalPos);
266 fNominalPos[0] = fVert.GetXv();
267 fNominalPos[1] = fVert.GetYv();
268 fNominalPos[2] = fVert.GetZv();
269 AliDebug(1,Form("No mean vertex: VertexFinder gives (%f, %f, %f)",fNominalPos[0],fNominalPos[1],fNominalPos[2]));
274 AliDebug(1,"No mean vertex and VertexFinder failed");
281 // propagate tracks to fNominalPos vertex
283 // if(constraint) reject for |d0|>5*fNSigma*sigma w.r.t. fNominal... vertex
284 // else reject for |d0|\oplus|z0| > 5 mm w.r.t. fNominal... vertex
286 // propagate tracks to best between initVertex and fCurrentVertex
287 // preselect tracks (reject for |d0|>fNSigma*sigma w.r.t. best
288 // between initVertex and fCurrentVertex)
289 for(Int_t iter=1; iter<=2; iter++) {
290 if(fOnlyFitter && iter==1) continue;
291 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
292 fIdSel = new UShort_t[nTrksOrig];
293 Int_t nTrksSel = PrepareTracks(*trkArrayOrig,idOrig,iter);
294 AliDebug(1,Form("N tracks selected in iteration %d: %d",iter,nTrksSel));
295 if(nTrksSel < fMinTracks) {
297 return fCurrentVertex;
303 AliDebug(1,"Just one track");
304 OneTrackVertFinder();
307 case 1: StrLinVertexFinderMinDist(1); break;
308 case 2: StrLinVertexFinderMinDist(0); break;
309 case 3: HelixVertexFinder(); break;
310 case 4: VertexFinder(1); break;
311 case 5: VertexFinder(0); break;
312 default: printf("Wrong algorithm"); break;
315 AliDebug(1," Vertex finding completed");
320 } // end loop on the two iterations
323 // set indices of used tracks
324 UShort_t *indices = 0;
325 if(fCurrentVertex->GetNContributors()>0) {
326 Int_t nIndices = (Int_t)fTrkArraySel.GetEntriesFast();
327 indices = new UShort_t[nIndices];
328 for(Int_t jj=0; jj<nIndices; jj++)
329 indices[jj] = fIdSel[jj];
330 fCurrentVertex->SetIndices(nIndices,indices);
332 delete [] indices; indices=NULL;
336 TString title="VertexerTracksNoConstraint";
338 title="VertexerTracksWithConstraint";
339 if(fOnlyFitter) title.Append("OnlyFitter");
341 fCurrentVertex->SetTitle(title.Data());
344 AliDebug(1,Form("xyz: %f %f %f; nc %d",fCurrentVertex->GetXv(),fCurrentVertex->GetYv(),fCurrentVertex->GetZv(),fCurrentVertex->GetNContributors()));
347 delete [] fIdSel; fIdSel=NULL;
348 fTrkArraySel.Delete();
349 if(fTrksToSkip) { delete [] fTrksToSkip; fTrksToSkip=NULL; }
352 return fCurrentVertex;
354 //------------------------------------------------------------------------
355 Double_t AliVertexerTracks::GetDeterminant3X3(Double_t matr[][3])
358 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];
361 //-------------------------------------------------------------------------
362 void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t (*m)[3],Double_t *d)
365 Double_t x12=p0[0]-p1[0];
366 Double_t y12=p0[1]-p1[1];
367 Double_t z12=p0[2]-p1[2];
368 Double_t kk=x12*x12+y12*y12+z12*z12;
369 m[0][0]=2-2/kk*x12*x12;
370 m[0][1]=-2/kk*x12*y12;
371 m[0][2]=-2/kk*x12*z12;
372 m[1][0]=-2/kk*x12*y12;
373 m[1][1]=2-2/kk*y12*y12;
374 m[1][2]=-2/kk*y12*z12;
375 m[2][0]=-2/kk*x12*z12;
377 m[2][2]=2-2/kk*z12*z12;
378 d[0]=2*p0[0]-2/kk*p0[0]*x12*x12-2/kk*p0[2]*x12*z12-2/kk*p0[1]*x12*y12;
379 d[1]=2*p0[1]-2/kk*p0[1]*y12*y12-2/kk*p0[0]*x12*y12-2/kk*p0[2]*z12*y12;
380 d[2]=2*p0[2]-2/kk*p0[2]*z12*z12-2/kk*p0[0]*x12*z12-2/kk*p0[1]*z12*y12;
383 //--------------------------------------------------------------------------
384 void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t *sigmasq,Double_t (*m)[3],Double_t *d)
387 Double_t x12=p1[0]-p0[0];
388 Double_t y12=p1[1]-p0[1];
389 Double_t z12=p1[2]-p0[2];
391 Double_t den= x12*x12*sigmasq[1]*sigmasq[2]+y12*y12*sigmasq[0]*sigmasq[2]+z12*z12*sigmasq[0]*sigmasq[1];
393 Double_t kk= 2*(x12*x12/sigmasq[0]+y12*y12/sigmasq[1]+z12*z12/sigmasq[2]);
396 cc[0]=-x12/sigmasq[0];
397 cc[1]=-y12/sigmasq[1];
398 cc[2]=-z12/sigmasq[2];
400 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;
402 Double_t ss= -p0[0]*cc[0]-p0[1]*cc[1]-p0[2]*cc[2];
405 aa[0]=x12*sigmasq[1]*sigmasq[2]/den;
406 aa[1]=y12*sigmasq[0]*sigmasq[2]/den;
407 aa[2]=z12*sigmasq[0]*sigmasq[1]/den;
409 m[0][0]=aa[0]*(aa[0]*kk+2*cc[0])+2*cc[0]*aa[0]+2/sigmasq[0];
410 m[0][1]=aa[1]*(aa[0]*kk+2*cc[0])+2*cc[1]*aa[0];
411 m[0][2]=aa[2]*(aa[0]*kk+2*cc[0])+2*cc[2]*aa[0];
413 m[1][0]=aa[0]*(aa[1]*kk+2*cc[1])+2*cc[0]*aa[1];
414 m[1][1]=aa[1]*(aa[1]*kk+2*cc[1])+2*cc[1]*aa[1]+2/sigmasq[1];
415 m[1][2]=aa[2]*(aa[1]*kk+2*cc[1])+2*cc[2]*aa[1];
417 m[2][0]=aa[0]*(aa[2]*kk+2*cc[2])+2*cc[0]*aa[2];
418 m[2][1]=aa[1]*(aa[2]*kk+2*cc[2])+2*cc[1]*aa[2];
419 m[2][2]=aa[2]*(aa[2]*kk+2*cc[2])+2*cc[2]*aa[2]+2/sigmasq[2];
421 d[0]=-ww*(aa[0]*kk+2*cc[0])-2*ss*aa[0]+2*p0[0]/sigmasq[0];
422 d[1]=-ww*(aa[1]*kk+2*cc[1])-2*ss*aa[1]+2*p0[1]/sigmasq[1];
423 d[2]=-ww*(aa[2]*kk+2*cc[2])-2*ss*aa[2]+2*p0[2]/sigmasq[2];
426 //--------------------------------------------------------------------------
427 Double_t AliVertexerTracks::GetStrLinMinDist(Double_t *p0,Double_t *p1,Double_t *x0)
430 Double_t x12=p0[0]-p1[0];
431 Double_t y12=p0[1]-p1[1];
432 Double_t z12=p0[2]-p1[2];
433 Double_t x10=p0[0]-x0[0];
434 Double_t y10=p0[1]-x0[1];
435 Double_t z10=p0[2]-x0[2];
436 // 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);
437 return ((y10*z12-z10*y12)*(y10*z12-z10*y12)+
438 (z10*x12-x10*z12)*(z10*x12-x10*z12)+
439 (x10*y12-y10*x12)*(x10*y12-y10*x12))
440 /(x12*x12+y12*y12+z12*z12);
442 //---------------------------------------------------------------------------
443 void AliVertexerTracks::OneTrackVertFinder()
445 // find vertex for events with 1 track, using DCA to nominal beam axis
446 AliDebug(1,Form("Number of prepared tracks =%d - Call OneTrackVertFinder",fTrkArraySel.GetEntries()));
447 AliExternalTrackParam *track1;
448 track1 = (AliExternalTrackParam*)fTrkArraySel.At(0);
449 Double_t alpha=track1->GetAlpha();
450 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
451 Double_t pos[3],dir[3];
452 track1->GetXYZAt(mindist,GetFieldkG(),pos);
453 track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
454 AliStrLine *line1 = new AliStrLine(pos,dir);
455 Double_t p1[3]={fNominalPos[0],fNominalPos[1],0.};
456 Double_t p2[3]={fNominalPos[0],fNominalPos[1],10.};
457 AliStrLine *zeta=new AliStrLine(p1,p2,kTRUE);
458 Double_t crosspoint[3]={0.,0.,0.};
461 Int_t retcode = zeta->Cross(line1,crosspoint);
463 sigma=line1->GetDistFromPoint(crosspoint);
468 fVert.SetXYZ(crosspoint);
469 fVert.SetDispersion(sigma);
470 fVert.SetNContributors(nContrib);
472 //---------------------------------------------------------------------------
473 void AliVertexerTracks::HelixVertexFinder()
475 // Get estimate of vertex position in (x,y) from tracks DCA
480 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
482 Int_t nacc = (Int_t)fTrkArraySel.GetEntriesFast();
484 Double_t aver[3]={0.,0.,0.};
485 Double_t averquad[3]={0.,0.,0.};
486 Double_t sigmaquad[3]={0.,0.,0.};
489 AliExternalTrackParam *track1;
490 AliExternalTrackParam *track2;
493 Double_t alpha, cs, sn;
494 Double_t crosspoint[3];
495 for(Int_t i=0; i<nacc; i++){
496 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
499 for(Int_t j=i+1; j<nacc; j++){
500 track2 = (AliExternalTrackParam*)fTrkArraySel.At(j);
502 distCA=track2->PropagateToDCA(track1,GetFieldkG());
503 if(fDCAcut<=0 ||(fDCAcut>0&&distCA<fDCAcut)){
505 alpha=track1->GetAlpha();
506 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
507 Double_t x1=x*cs - track1->GetY()*sn;
508 Double_t y1=x*sn + track1->GetY()*cs;
509 Double_t z1=track1->GetZ();
511 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
513 alpha=track2->GetAlpha();
514 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
515 Double_t x2=x*cs - track2->GetY()*sn;
516 Double_t y2=x*sn + track2->GetY()*cs;
517 Double_t z2=track2->GetZ();
518 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
519 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
520 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
521 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
522 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
523 crosspoint[0]=wx1*x1 + wx2*x2;
524 crosspoint[1]=wy1*y1 + wy2*y2;
525 crosspoint[2]=wz1*z1 + wz2*z2;
528 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
529 for(Int_t jj=0;jj<3;jj++)averquad[jj]+=(crosspoint[jj]*crosspoint[jj]);
535 for(Int_t jj=0;jj<3;jj++){
536 initPos[jj] = aver[jj]/ncombi;
537 averquad[jj]/=ncombi;
538 sigmaquad[jj]=averquad[jj]-initPos[jj]*initPos[jj];
539 sigma+=sigmaquad[jj];
541 sigma=TMath::Sqrt(TMath::Abs(sigma));
544 Warning("HelixVertexFinder","Finder did not succed");
547 fVert.SetXYZ(initPos);
548 fVert.SetDispersion(sigma);
549 fVert.SetNContributors(ncombi);
551 //----------------------------------------------------------------------------
552 Int_t AliVertexerTracks::PrepareTracks(TObjArray &trkArrayOrig,
557 // Propagate tracks to initial vertex position and store them in a TObjArray
559 AliDebug(1," PrepareTracks()");
561 Int_t nTrksOrig = (Int_t)trkArrayOrig.GetEntriesFast();
564 Double_t sigmaCurr[3];
565 Double_t normdistx,normdisty;
566 Double_t d0z0[2],covd0z0[3];
569 AliESDVertex *initVertex = new AliESDVertex(fNominalPos,fNominalCov,1,1);
571 if(!fTrkArraySel.IsEmpty()) fTrkArraySel.Delete();
573 AliExternalTrackParam *track=0;
576 for(Int_t i=0; i<nTrksOrig; i++) {
577 AliExternalTrackParam *trackOrig=(AliExternalTrackParam*)trkArrayOrig.At(i);
578 if(trackOrig->Charge()!=0) { // normal tracks
579 track = new AliExternalTrackParam(*(AliExternalTrackParam*)trkArrayOrig.At(i));
580 } else { // neutral tracks (from a V0)
581 track = new AliNeutralTrackParam(*(AliNeutralTrackParam*)trkArrayOrig.At(i));
584 if(TMath::Abs(track->GetTgl())>fMaxTgl) {
585 AliDebug(1,Form(" rejecting track with tgl = %f",track->GetTgl()));
586 delete track; continue;
589 Bool_t propagateOK = kFALSE;
590 // propagate track to vertex
591 if(optImpParCut<2 || fOnlyFitter) { // optImpParCut==1 or 0
592 propagateOK = track->PropagateToDCA(initVertex,GetFieldkG(),100.,d0z0,covd0z0);
593 } else { // optImpParCut==2
594 fCurrentVertex->GetSigmaXYZ(sigmaCurr);
595 normdistx = TMath::Abs(fCurrentVertex->GetXv()-fNominalPos[0])/TMath::Sqrt(sigmaCurr[0]*sigmaCurr[0]+fNominalCov[0]);
596 normdisty = TMath::Abs(fCurrentVertex->GetYv()-fNominalPos[1])/TMath::Sqrt(sigmaCurr[1]*sigmaCurr[1]+fNominalCov[2]);
597 if(normdistx < 3. && normdisty < 3. &&
598 (sigmaCurr[0]+sigmaCurr[1])<(TMath::Sqrt(fNominalCov[0])+TMath::Sqrt(fNominalCov[2]))) {
599 propagateOK = track->PropagateToDCA(fCurrentVertex,GetFieldkG(),100.,d0z0,covd0z0);
601 propagateOK = track->PropagateToDCA(initVertex,GetFieldkG(),100.,d0z0,covd0z0);
606 AliDebug(1," rejected");
607 delete track; continue;
610 sigmad0 = TMath::Sqrt(covd0z0[0]);
611 maxd0rphi = fNSigma*sigmad0;
612 if(optImpParCut==1) maxd0rphi *= 5.;
613 maxd0rphi = TMath::Min(maxd0rphi,fFiducialR);
614 //sigmad0z0 = TMath::Sqrt(covd0z0[0]+covd0z0[2]); // for future improvement
615 //maxd0z0 = 10.*fNSigma*sigmad0z0;
617 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));
620 //---- track selection based on impact parameters ----//
622 // always reject tracks outside fiducial volume
623 if(TMath::Abs(d0z0[0])>fFiducialR || TMath::Abs(d0z0[1])>fFiducialZ) {
624 AliDebug(1," rejected");
625 delete track; continue;
628 // during iterations 1 and 2 , reject tracks with d0rphi > maxd0rphi
629 if(optImpParCut>0 && TMath::Abs(d0z0[0])>maxd0rphi) {
630 AliDebug(1," rejected");
631 delete track; continue;
634 // if fConstraint=kFALSE, during iterations 1 and 2 ||
635 // if fConstraint=kTRUE, during iteration 2,
636 // select tracks with d0oplusz0 < fMaxd0z0
637 if((!fConstraint && optImpParCut>0 && fVert.GetNContributors()>0) ||
638 ( fConstraint && optImpParCut==2)) {
640 TMath::Sqrt(d0z0[0]*d0z0[0]+d0z0[1]*d0z0[1])>fMaxd0z0) {
641 AliDebug(1," rejected");
642 delete track; continue;
646 // track passed all selections
647 fTrkArraySel.AddLast(track);
648 fIdSel[nTrksSel] = idOrig[i];
650 } // end loop on tracks
656 //----------------------------------------------------------------------------
657 Bool_t AliVertexerTracks::PropagateTrackTo(AliExternalTrackParam *track,
659 //----------------------------------------------------------------
660 // COPIED from AliTracker
662 // Propagates the track to the plane X=xk (cm).
664 // Origin: Marian Ivanov, Marian.Ivanov@cern.ch
665 //----------------------------------------------------------------
667 const Double_t kEpsilon = 0.00001;
668 Double_t xpos = track->GetX();
669 Double_t dir = (xpos<xToGo) ? 1. : -1.;
670 Double_t maxStep = 5;
671 Double_t maxSnp = 0.8;
673 while ( (xToGo-xpos)*dir > kEpsilon){
674 Double_t step = dir*TMath::Min(TMath::Abs(xToGo-xpos), maxStep);
675 Double_t x = xpos+step;
676 Double_t xyz0[3],xyz1[3];
677 track->GetXYZ(xyz0); //starting global position
679 if(!track->GetXYZAt(x,GetFieldkG(),xyz1)) return kFALSE; // no prolongation
680 xyz1[2]+=kEpsilon; // waiting for bug correction in geo
682 if(TMath::Abs(track->GetSnpAt(x,GetFieldkG())) >= maxSnp) return kFALSE;
683 if(!track->PropagateTo(x,GetFieldkG())) return kFALSE;
685 if(TMath::Abs(track->GetSnp()) >= maxSnp) return kFALSE;
686 track->GetXYZ(xyz0); // global position
687 Double_t alphan = TMath::ATan2(xyz0[1], xyz0[0]);
689 Double_t ca=TMath::Cos(alphan-track->GetAlpha()),
690 sa=TMath::Sin(alphan-track->GetAlpha());
691 Double_t sf=track->GetSnp(), cf=TMath::Sqrt((1.-sf)*(1.+sf));
692 Double_t sinNew = sf*ca - cf*sa;
693 if(TMath::Abs(sinNew) >= maxSnp) return kFALSE;
694 if(!track->Rotate(alphan)) return kFALSE;
696 xpos = track->GetX();
700 //---------------------------------------------------------------------------
701 AliESDVertex* AliVertexerTracks::RemoveTracksFromVertex(AliESDVertex *inVtx,
707 // Removes tracks in trksTree from fit of inVtx
710 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraint")) {
711 printf("ERROR: primary vertex has no constraint: cannot remove tracks");
714 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraintOnlyFitter"))
715 printf("WARNING: result of tracks' removal will be only approximately correct");
718 rv(0,0) = inVtx->GetXv();
719 rv(1,0) = inVtx->GetYv();
720 rv(2,0) = inVtx->GetZv();
723 inVtx->GetCovMatrix(cov);
725 vV(0,1) = cov[1]; vV(1,0) = cov[1];
727 vV(0,2) = cov[3]; vV(2,0) = cov[3];
728 vV(1,2) = cov[4]; vV(2,1) = cov[4];
731 TMatrixD sumWi(TMatrixD::kInverted,vV);
732 TMatrixD sumWiri(sumWi,TMatrixD::kMult,rv);
734 Int_t nUsedTrks = inVtx->GetNIndices();
735 Double_t chi2 = inVtx->GetChi2();
737 AliExternalTrackParam *track = 0;
738 Int_t ntrks = (Int_t)trkArray->GetEntriesFast();
739 for(Int_t i=0;i<ntrks;i++) {
740 track = (AliExternalTrackParam*)trkArray->At(i);
741 if(!inVtx->UsesTrack(id[i])) {
742 printf("track %d was not used in vertex fit",id[i]);
745 Double_t alpha = track->GetAlpha();
746 Double_t xl = diamondxy[0]*TMath::Cos(alpha)+diamondxy[1]*TMath::Sin(alpha);
747 track->PropagateTo(xl,GetFieldkG());
748 // vector of track global coordinates
750 // covariance matrix of ri
753 // get space point from track
754 if(!TrackToPoint(track,ri,wWi)) continue;
756 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
762 TMatrixD deltar = rv; deltar -= ri;
763 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
764 Double_t chi2i = deltar(0,0)*wWideltar(0,0)+
765 deltar(1,0)*wWideltar(1,0)+
766 deltar(2,0)*wWideltar(2,0);
767 // remove from total chi2
772 printf("Trying to remove too many tracks!");
780 // new inverted of weights matrix
781 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
783 // new position of primary vertex
784 rvnew.Mult(vVnew,sumWiri);
786 Double_t position[3];
787 position[0] = rvnew(0,0);
788 position[1] = rvnew(1,0);
789 position[2] = rvnew(2,0);
797 // store data in the vertex object
798 AliESDVertex *outVtx = new AliESDVertex(position,cov,chi2,nUsedTrks);
799 outVtx->SetTitle(inVtx->GetTitle());
800 UShort_t *inindices = inVtx->GetIndices();
801 Int_t nIndices = nUsedTrks;
802 UShort_t *outindices = new UShort_t[nIndices];
804 for(Int_t k=0; k<inVtx->GetNIndices(); k++) {
805 Bool_t copyindex=kTRUE;
806 for(Int_t l=0; l<ntrks; l++) {
807 if(inindices[k]==id[l]) copyindex=kFALSE;
810 outindices[j] = inindices[k]; j++;
813 outVtx->SetIndices(nIndices,outindices);
814 delete [] outindices;
817 printf("Vertex before removing tracks:");
818 inVtx->PrintStatus();
819 inVtx->PrintIndices();
820 printf("Vertex after removing tracks:");
821 outVtx->PrintStatus();
822 outVtx->PrintIndices();
827 //---------------------------------------------------------------------------
828 void AliVertexerTracks::SetCuts(Double_t *cuts)
834 SetDCAcutIter0(cuts[1]);
836 if(fMode==0 && cuts[3]<0) SetITSrefitNotRequired();
837 SetMinClusters((Int_t)(TMath::Abs(cuts[3])));
838 SetMinTracks((Int_t)(cuts[4]));
839 SetNSigmad0(cuts[5]);
840 SetMinDetFitter(cuts[6]);
842 SetFiducialRZ(cuts[8],cuts[9]);
843 fAlgo=(Int_t)(cuts[10]);
844 fAlgoIter0=(Int_t)(cuts[11]);
848 //---------------------------------------------------------------------------
849 void AliVertexerTracks::SetITSMode(Double_t dcacut,
850 Double_t dcacutIter0,
855 Double_t mindetfitter,
860 Int_t finderAlgoIter0)
863 // Cut values for ITS mode
867 SetITSrefitRequired();
869 SetITSrefitNotRequired();
872 SetDCAcutIter0(dcacutIter0);
874 SetMinClusters(TMath::Abs(minCls));
875 SetMinTracks(mintrks);
877 SetMinDetFitter(mindetfitter);
879 SetFiducialRZ(fidR,fidZ);
881 fAlgoIter0=finderAlgoIter0;
885 //---------------------------------------------------------------------------
886 void AliVertexerTracks::SetTPCMode(Double_t dcacut,
887 Double_t dcacutIter0,
892 Double_t mindetfitter,
897 Int_t finderAlgoIter0)
900 // Cut values for TPC mode
903 SetITSrefitNotRequired();
905 SetDCAcutIter0(dcacutIter0);
907 SetMinClusters(minCls);
908 SetMinTracks(mintrks);
910 SetMinDetFitter(mindetfitter);
912 SetFiducialRZ(fidR,fidZ);
914 fAlgoIter0=finderAlgoIter0;
918 //---------------------------------------------------------------------------
919 void AliVertexerTracks::SetSkipTracks(Int_t n,Int_t *skipped)
922 // Mark the tracks not to be used in the vertex reconstruction.
923 // Tracks are identified by AliESDtrack::GetID()
925 fNTrksToSkip = n; fTrksToSkip = new Int_t[n];
926 for(Int_t i=0;i<n;i++) fTrksToSkip[i] = skipped[i];
929 //---------------------------------------------------------------------------
930 void AliVertexerTracks::SetVtxStart(AliESDVertex *vtx)
933 // Set initial vertex knowledge
935 vtx->GetXYZ(fNominalPos);
936 vtx->GetCovMatrix(fNominalCov);
940 //---------------------------------------------------------------------------
941 void AliVertexerTracks::StrLinVertexFinderMinDist(Int_t optUseWeights)
943 AliExternalTrackParam *track1;
944 const Int_t knacc = (Int_t)fTrkArraySel.GetEntriesFast();
945 static TClonesArray linarray("AliStrLine",knacc);
946 for(Int_t i=0; i<knacc; i++){
947 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
948 Double_t alpha=track1->GetAlpha();
949 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
950 Double_t pos[3],dir[3],sigmasq[3];
951 track1->GetXYZAt(mindist,GetFieldkG(),pos);
952 track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
953 sigmasq[0]=TMath::Sin(alpha)*TMath::Sin(alpha)*track1->GetSigmaY2();
954 sigmasq[1]=TMath::Cos(alpha)*TMath::Cos(alpha)*track1->GetSigmaY2();
955 sigmasq[2]=track1->GetSigmaZ2();
958 //if(!TrackToPoint(track1,ri,wWi)) {printf("WARNING\n");continue;}
959 if(!TrackToPoint(track1,ri,wWi)) {optUseWeights=kFALSE;printf("WARNING\n");}
962 for(Int_t ia=0;ia<3;ia++){
963 for(Int_t ib=0;ib<3;ib++){
964 wmat[iel]=wWi(ia,ib);
968 new(linarray[i]) AliStrLine(pos,sigmasq,wmat,dir);
970 fVert=TrackletVertexFinder(&linarray,optUseWeights);
973 //---------------------------------------------------------------------------
974 AliESDVertex AliVertexerTracks::TrackletVertexFinder(TClonesArray *lines, Int_t optUseWeights)
976 // Calculate the point at minimum distance to prepared tracks
977 const Int_t knacc = (Int_t)lines->GetEntriesFast();
978 Double_t initPos[3]={0.,0.,0.};
980 Double_t (*vectP0)[3]=new Double_t [knacc][3];
981 Double_t (*vectP1)[3]=new Double_t [knacc][3];
984 Double_t dsum[3]={0,0,0};
986 for(Int_t i=0;i<3;i++){
987 for(Int_t j=0;j<3;j++){
993 for(Int_t i=0; i<knacc; i++){
994 AliStrLine* line1 = (AliStrLine*)lines->At(i);
995 Double_t p0[3],cd[3],sigmasq[3];
997 if(!line1) printf("ERROR %d %d\n",i,knacc);
1000 line1->GetSigma2P0(sigmasq);
1001 line1->GetWMatrix(wmat);
1004 for(Int_t ia=0;ia<3;ia++){
1005 for(Int_t ib=0;ib<3;ib++){
1006 wWi(ia,ib)=wmat[iel];
1013 Double_t p1[3]={p0[0]+cd[0],p0[1]+cd[1],p0[2]+cd[2]};
1021 Double_t matr[3][3];
1023 if(optUseWeights==0)GetStrLinDerivMatrix(p0,p1,matr,dknow);
1024 else GetStrLinDerivMatrix(p0,p1,sigmasq,matr,dknow);
1027 for(Int_t iii=0;iii<3;iii++){
1028 dsum[iii]+=dknow[iii];
1029 for(Int_t lj=0;lj<3;lj++) sum[iii][lj]+=matr[iii][lj];
1033 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
1034 Double_t covmatrix[6];
1035 covmatrix[0] = invsumWi(0,0);
1036 covmatrix[1] = invsumWi(0,1);
1037 covmatrix[2] = invsumWi(1,1);
1038 covmatrix[3] = invsumWi(0,2);
1039 covmatrix[4] = invsumWi(1,2);
1040 covmatrix[5] = invsumWi(2,2);
1042 Double_t vett[3][3];
1043 Double_t det=GetDeterminant3X3(sum);
1047 for(Int_t zz=0;zz<3;zz++){
1048 for(Int_t ww=0;ww<3;ww++){
1049 for(Int_t kk=0;kk<3;kk++) vett[ww][kk]=sum[ww][kk];
1051 for(Int_t kk=0;kk<3;kk++) vett[kk][zz]=dsum[kk];
1052 initPos[zz]=GetDeterminant3X3(vett)/det;
1056 for(Int_t i=0; i<knacc; i++){
1057 Double_t p0[3]={0,0,0},p1[3]={0,0,0};
1058 for(Int_t ii=0;ii<3;ii++){
1059 p0[ii]=vectP0[i][ii];
1060 p1[ii]=vectP1[i][ii];
1062 sigma+=GetStrLinMinDist(p0,p1,initPos);
1065 if(sigma>0.) {sigma=TMath::Sqrt(sigma);}else{sigma=999;}
1069 AliESDVertex theVert(initPos,covmatrix,99999.,knacc);
1070 theVert.SetDispersion(sigma);
1075 //---------------------------------------------------------------------------
1076 Bool_t AliVertexerTracks::TrackToPoint(AliExternalTrackParam *t,
1077 TMatrixD &ri,TMatrixD &wWi,
1078 Bool_t uUi3by3) const
1081 // Extract from the AliExternalTrackParam the global coordinates ri and covariance matrix
1082 // wWi of the space point that it represents (to be used in VertexFitter())
1086 Double_t rotAngle = t->GetAlpha();
1087 if(rotAngle<0.) rotAngle += 2.*TMath::Pi();
1088 Double_t cosRot = TMath::Cos(rotAngle);
1089 Double_t sinRot = TMath::Sin(rotAngle);
1091 ri(0,0) = t->GetX()*cosRot-t->GetY()*sinRot;
1092 ri(1,0) = t->GetX()*sinRot+t->GetY()*cosRot;
1093 ri(2,0) = t->GetZ();
1098 // matrix to go from global (x,y,z) to local (y,z);
1107 // covariance matrix of local (y,z) - inverted
1109 uUi(0,0) = t->GetSigmaY2();
1110 uUi(0,1) = t->GetSigmaZY();
1111 uUi(1,0) = t->GetSigmaZY();
1112 uUi(1,1) = t->GetSigmaZ2();
1114 //printf(" %f %f",uUi(0,0),uUi(0,1));
1115 //printf(" %f %f",uUi(1,0),uUi(1,1));
1117 if(uUi.Determinant() <= 0.) return kFALSE;
1118 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
1120 // weights matrix: wWi = qQiT * uUiInv * qQi
1121 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
1122 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
1125 if(fVert.GetNContributors()<1) AliFatal("Vertex from finder is empty");
1126 // matrix to go from global (x,y,z) to local (x,y,z);
1138 // covariance of fVert along the track
1139 Double_t p[3],pt,ptot;
1141 pt = TMath::Sqrt(p[0]*p[0]+p[1]*p[1]);
1142 ptot = TMath::Sqrt(pt*pt+p[2]*p[2]);
1143 Double_t cphi = p[0]/pt; //cos(phi)=px/pt
1144 Double_t sphi = p[1]/pt; //sin(phi)=py/pt
1145 Double_t clambda = pt/ptot; //cos(lambda)=pt/ptot
1146 Double_t slambda = p[2]/ptot; //sin(lambda)=pz/ptot
1147 Double_t covfVert[6];
1148 fVert.GetCovMatrix(covfVert);
1149 Double_t covfVertalongt =
1150 covfVert[0]*cphi*cphi*clambda*clambda
1151 +covfVert[1]*2.*cphi*sphi*clambda*clambda
1152 +covfVert[3]*2.*cphi*clambda*slambda
1153 +covfVert[2]*sphi*sphi*clambda*clambda
1154 +covfVert[4]*2.*sphi*clambda*slambda
1155 +covfVert[5]*slambda*slambda;
1156 // covariance matrix of local (x,y,z) - inverted
1158 uUi(0,0) = covfVertalongt * fnSigmaForUi00 * fnSigmaForUi00;
1159 AliDebug(1,Form("=====> sqrtUi00 cm %f",TMath::Sqrt(uUi(0,0))));
1163 uUi(1,1) = t->GetSigmaY2();
1164 uUi(1,2) = t->GetSigmaZY();
1166 uUi(2,1) = t->GetSigmaZY();
1167 uUi(2,2) = t->GetSigmaZ2();
1168 //printf(" Ui :\n");
1169 //printf(" %f %f\n",uUi(0,0),uUi(0,1));
1170 //printf(" %f %f\n",uUi(1,0),uUi(1,1));
1172 if(uUi.Determinant() <= 0.) return kFALSE;
1173 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
1175 // weights matrix: wWi = qQiT * uUiInv * qQi
1176 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
1177 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
1184 //---------------------------------------------------------------------------
1185 void AliVertexerTracks::TooFewTracks()
1188 // When the number of tracks is < fMinTracks,
1189 // deal with vertices not found and prepare to exit
1191 AliDebug(1,"TooFewTracks");
1193 Double_t pos[3],err[3];
1194 pos[0] = fNominalPos[0];
1195 err[0] = TMath::Sqrt(fNominalCov[0]);
1196 pos[1] = fNominalPos[1];
1197 err[1] = TMath::Sqrt(fNominalCov[2]);
1198 pos[2] = fNominalPos[2];
1199 err[2] = TMath::Sqrt(fNominalCov[5]);
1200 Int_t ncontr = (err[0]>1. ? -1 : -3);
1201 if(fCurrentVertex) { delete fCurrentVertex; fCurrentVertex=0; }
1202 fCurrentVertex = new AliESDVertex(pos,err);
1203 fCurrentVertex->SetNContributors(ncontr);
1206 fCurrentVertex->SetTitle("VertexerTracksWithConstraint");
1208 fCurrentVertex->SetTitle("VertexerTracksNoConstraint");
1211 if(!fTrkArraySel.IsEmpty()) fTrkArraySel.Delete();
1212 if(fIdSel) {delete [] fIdSel; fIdSel=NULL;}
1213 if(fTrksToSkip) {delete [] fTrksToSkip; fTrksToSkip=NULL;}
1217 //---------------------------------------------------------------------------
1218 void AliVertexerTracks::VertexFinder(Int_t optUseWeights)
1221 // Get estimate of vertex position in (x,y) from tracks DCA
1223 Double_t initPos[3];
1225 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
1226 Int_t nacc = (Int_t)fTrkArraySel.GetEntriesFast();
1227 Double_t aver[3]={0.,0.,0.};
1228 Double_t aversq[3]={0.,0.,0.};
1229 Double_t sigmasq[3]={0.,0.,0.};
1232 AliExternalTrackParam *track1;
1233 AliExternalTrackParam *track2;
1234 Double_t pos[3],dir[3];
1235 Double_t alpha,mindist;
1237 for(Int_t i=0; i<nacc; i++){
1238 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
1239 alpha=track1->GetAlpha();
1240 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1241 track1->GetXYZAt(mindist,GetFieldkG(),pos);
1242 track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
1243 AliStrLine *line1 = new AliStrLine(pos,dir);
1245 // AliStrLine *line1 = new AliStrLine();
1246 // track1->ApproximateHelixWithLine(mindist,GetFieldkG(),line1);
1248 for(Int_t j=i+1; j<nacc; j++){
1249 track2 = (AliExternalTrackParam*)fTrkArraySel.At(j);
1250 alpha=track2->GetAlpha();
1251 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1252 track2->GetXYZAt(mindist,GetFieldkG(),pos);
1253 track2->GetPxPyPzAt(mindist,GetFieldkG(),dir);
1254 AliStrLine *line2 = new AliStrLine(pos,dir);
1255 // AliStrLine *line2 = new AliStrLine();
1256 // track2->ApproximateHelixWithLine(mindist,GetFieldkG(),line2);
1257 Double_t distCA=line2->GetDCA(line1);
1258 //printf("%d %d %f\n",i,j,distCA);
1259 if(fDCAcut<=0 || (fDCAcut>0&&distCA<fDCAcut)){
1260 Double_t pnt1[3],pnt2[3],crosspoint[3];
1262 if(optUseWeights<=0){
1263 Int_t retcode = line2->Cross(line1,crosspoint);
1266 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
1267 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1270 if(optUseWeights>0){
1271 Int_t retcode = line1->CrossPoints(line2,pnt1,pnt2);
1274 alpha=track1->GetAlpha();
1275 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
1276 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
1277 alpha=track2->GetAlpha();
1278 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
1279 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
1280 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
1281 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
1282 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
1283 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
1284 crosspoint[0]=wx1*pnt1[0] + wx2*pnt2[0];
1285 crosspoint[1]=wy1*pnt1[1] + wy2*pnt2[1];
1286 crosspoint[2]=wz1*pnt1[2] + wz2*pnt2[2];
1289 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
1290 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1299 for(Int_t jj=0;jj<3;jj++){
1300 initPos[jj] = aver[jj]/ncombi;
1301 //printf("%f\n",initPos[jj]);
1303 sigmasq[jj]=aversq[jj]-initPos[jj]*initPos[jj];
1306 sigma=TMath::Sqrt(TMath::Abs(sigma));
1309 Warning("VertexFinder","Finder did not succed");
1312 fVert.SetXYZ(initPos);
1313 fVert.SetDispersion(sigma);
1314 fVert.SetNContributors(ncombi);
1316 //---------------------------------------------------------------------------
1317 void AliVertexerTracks::VertexFitter()
1320 // The optimal estimate of the vertex position is given by a "weighted
1321 // average of tracks positions".
1322 // Original method: V. Karimaki, CMS Note 97/0051
1324 Bool_t useConstraint = fConstraint;
1325 Double_t initPos[3];
1327 fVert.GetXYZ(initPos);
1329 initPos[0]=fNominalPos[0];
1330 initPos[1]=fNominalPos[1];
1331 initPos[2]=fNominalPos[2];
1334 Int_t nTrksSel = (Int_t)fTrkArraySel.GetEntries();
1335 if(nTrksSel==1) useConstraint=kTRUE;
1336 AliDebug(1,"--- VertexFitter(): start");
1337 AliDebug(1,Form(" Number of tracks in array: %d\n",nTrksSel));
1338 AliDebug(1,Form(" Minimum # tracks required in fit: %d\n",fMinTracks));
1339 AliDebug(1,Form(" Vertex position after finder: %f,%f,%f\n",initPos[0],initPos[1],initPos[2]));
1340 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])));
1342 // special treatment for few-tracks fits (e.g. secondary vertices)
1343 Bool_t uUi3by3 = kFALSE; if(nTrksSel<5 && !useConstraint) uUi3by3 = kTRUE;
1348 rv(0,0) = initPos[0];
1349 rv(1,0) = initPos[1];
1351 Double_t xlStart,alpha;
1353 Double_t chi2,chi2i,chi2b;
1354 AliExternalTrackParam *t = 0;
1357 // initial vertex covariance matrix
1359 vVb(0,0) = fNominalCov[0];
1360 vVb(0,1) = fNominalCov[1];
1362 vVb(1,0) = fNominalCov[1];
1363 vVb(1,1) = fNominalCov[2];
1367 vVb(2,2) = fNominalCov[5];
1368 TMatrixD vVbInv(TMatrixD::kInverted,vVb);
1370 rb(0,0) = fNominalPos[0];
1371 rb(1,0) = fNominalPos[1];
1372 rb(2,0) = fNominalPos[2];
1373 TMatrixD vVbInvrb(vVbInv,TMatrixD::kMult,rb);
1377 // 1st - estimate of vtx using all tracks
1378 // 2nd - estimate of global chi2
1379 for(step=0; step<2; step++) {
1380 AliDebug(1,Form(" step = %d\n",step));
1384 if(step==1) { initPos[0]=rv(0,0); initPos[0]=rv(1,0); }
1386 TMatrixD sumWiri(3,1);
1387 TMatrixD sumWi(3,3);
1388 for(i=0; i<3; i++) {
1390 for(j=0; j<3; j++) sumWi(j,i) = 0.;
1393 // mean vertex constraint
1396 sumWiri(i,0) += vVbInvrb(i,0);
1397 for(k=0;k<3;k++) sumWi(i,k) += vVbInv(i,k);
1400 TMatrixD deltar = rv; deltar -= rb;
1401 TMatrixD vVbInvdeltar(vVbInv,TMatrixD::kMult,deltar);
1402 chi2b = deltar(0,0)*vVbInvdeltar(0,0)+
1403 deltar(1,0)*vVbInvdeltar(1,0)+
1404 deltar(2,0)*vVbInvdeltar(2,0);
1409 for(k=0; k<nTrksSel; k++) {
1410 // get track from track array
1411 t = (AliExternalTrackParam*)fTrkArraySel.At(k);
1412 alpha = t->GetAlpha();
1413 xlStart = initPos[0]*TMath::Cos(alpha)+initPos[1]*TMath::Sin(alpha);
1414 // to vtxSeed (from finder)
1415 t->PropagateTo(xlStart,GetFieldkG());
1417 // vector of track global coordinates
1419 // covariance matrix of ri
1422 // get space point from track
1423 if(!TrackToPoint(t,ri,wWi,uUi3by3)) continue;
1424 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
1427 TMatrixD deltar = rv; deltar -= ri;
1428 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
1429 chi2i = deltar(0,0)*wWideltar(0,0)+
1430 deltar(1,0)*wWideltar(1,0)+
1431 deltar(2,0)*wWideltar(2,0);
1433 // add to total chi2
1440 } // end loop on tracks
1442 if(nTrksUsed < fMinTracks) {
1447 Double_t determinant = sumWi.Determinant();
1448 if(determinant < fMinDetFitter) {
1449 AliDebug(1,Form("det(V) = %f (<%f)\n",determinant,fMinDetFitter));
1455 // inverted of weights matrix
1456 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
1458 // position of primary vertex
1459 rv.Mult(vV,sumWiri);
1461 } // end loop on the 2 steps
1468 Double_t position[3];
1469 position[0] = rv(0,0);
1470 position[1] = rv(1,0);
1471 position[2] = rv(2,0);
1472 Double_t covmatrix[6];
1473 covmatrix[0] = vV(0,0);
1474 covmatrix[1] = vV(0,1);
1475 covmatrix[2] = vV(1,1);
1476 covmatrix[3] = vV(0,2);
1477 covmatrix[4] = vV(1,2);
1478 covmatrix[5] = vV(2,2);
1480 // for correct chi2/ndf, count constraint as additional "track"
1481 if(fConstraint) nTrksUsed++;
1482 // store data in the vertex object
1483 if(fCurrentVertex) { delete fCurrentVertex; fCurrentVertex=0; }
1484 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nTrksUsed);
1486 AliDebug(1," Vertex after fit:");
1487 AliDebug(1,Form("xyz: %f %f %f; nc %d",fCurrentVertex->GetXv(),fCurrentVertex->GetYv(),fCurrentVertex->GetZv(),fCurrentVertex->GetNContributors()));
1488 AliDebug(1,"--- VertexFitter(): finish\n");
1493 //----------------------------------------------------------------------------
1494 AliESDVertex* AliVertexerTracks::VertexForSelectedTracks(TObjArray *trkArray,
1496 Bool_t optUseFitter,
1497 Bool_t optPropagate)
1500 // Return vertex from tracks (AliExternalTrackParam) in array
1505 // get tracks and propagate them to initial vertex position
1506 fIdSel = new UShort_t[(Int_t)trkArray->GetEntriesFast()];
1507 Int_t nTrksSel = PrepareTracks(*trkArray,id,0);
1508 if(nTrksSel < TMath::Max(2,fMinTracks)) {
1510 return fCurrentVertex;
1515 case 1: StrLinVertexFinderMinDist(1); break;
1516 case 2: StrLinVertexFinderMinDist(0); break;
1517 case 3: HelixVertexFinder(); break;
1518 case 4: VertexFinder(1); break;
1519 case 5: VertexFinder(0); break;
1520 default: printf("Wrong algorithm\n"); break;
1522 AliDebug(1," Vertex finding completed\n");
1528 Double_t position[3]={fVert.GetXv(),fVert.GetYv(),fVert.GetZv()};
1529 Double_t covmatrix[6];
1530 fVert.GetCovMatrix(covmatrix);
1531 Double_t chi2=99999.;
1532 Int_t nTrksUsed=fVert.GetNContributors();
1533 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nTrksUsed);
1535 fCurrentVertex->SetDispersion(fVert.GetDispersion());
1538 // set indices of used tracks and propagate track to found vertex
1539 UShort_t *indices = 0;
1540 Double_t d0z0[2],covd0z0[3];
1541 AliExternalTrackParam *t = 0;
1542 if(fCurrentVertex->GetNContributors()>0) {
1543 indices = new UShort_t[fCurrentVertex->GetNContributors()];
1544 for(Int_t jj=0; jj<(Int_t)fTrkArraySel.GetEntriesFast(); jj++) {
1545 indices[jj] = fIdSel[jj];
1546 t = (AliExternalTrackParam*)fTrkArraySel.At(jj);
1547 if(optPropagate && optUseFitter) {
1548 if(TMath::Sqrt(fCurrentVertex->GetXv()*fCurrentVertex->GetXv()+fCurrentVertex->GetYv()*fCurrentVertex->GetYv())<3.) {
1549 t->PropagateToDCA(fCurrentVertex,GetFieldkG(),100.,d0z0,covd0z0);
1550 AliDebug(1,Form("Track %d propagated to found vertex",jj));
1552 AliWarning("Found vertex outside beam pipe!");
1556 fCurrentVertex->SetIndices(fCurrentVertex->GetNContributors(),indices);
1560 delete [] indices; indices=NULL;
1561 delete [] fIdSel; fIdSel=NULL;
1562 fTrkArraySel.Delete();
1564 return fCurrentVertex;
1566 //----------------------------------------------------------------------------
1567 AliESDVertex* AliVertexerTracks::VertexForSelectedESDTracks(TObjArray *trkArray,
1568 Bool_t optUseFitter,
1569 Bool_t optPropagate)
1572 // Return vertex from array of ESD tracks
1575 Int_t nTrks = (Int_t)trkArray->GetEntriesFast();
1576 UShort_t *id = new UShort_t[nTrks];
1578 AliESDtrack *esdt = 0;
1579 for(Int_t i=0; i<nTrks; i++){
1580 esdt = (AliESDtrack*)trkArray->At(i);
1581 id[i] = (UShort_t)esdt->GetID();
1584 VertexForSelectedTracks(trkArray,id,optUseFitter,optPropagate);
1586 delete [] id; id=NULL;
1588 return fCurrentVertex;
1590 //--------------------------------------------------------------------------