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(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;
180 if(fMode==0 && fITSrefit && !(track->GetStatus()&AliESDtrack::kITSrefit)) continue;
182 if(!inputAOD) { // ESD
183 AliESDtrack* esdt = (AliESDtrack*)track;
184 if(esdt->GetNcls(fMode) < fMinClusters) continue;
185 if(fMode==0) { // ITS mode
186 Double_t x,p[5],cov[15];
187 esdt->GetExternalParameters(x,p);
188 esdt->GetExternalCovariance(cov);
189 t = new AliExternalTrackParam(x,esdt->GetAlpha(),p,cov);
190 } else if(fMode==1) { // TPC mode
191 t = (AliExternalTrackParam*)esdt->GetTPCInnerParam();
193 Double_t radius = 2.8; //something less than the beam pipe radius
194 if(!PropagateTrackTo(t,radius)) continue;
196 } else { // AOD (only ITS mode)
198 for(Int_t l=0;l<6;l++) if(TESTBIT(track->GetITSClusterMap(),l)) ncls0++;
199 if(ncls0 < fMinClusters) continue;
200 t = new AliExternalTrackParam(track);
202 trkArrayOrig.AddLast(t);
203 idOrig[nTrksOrig]=(UShort_t)track->GetID();
205 } // end loop on tracks
207 // call method that will reconstruct the vertex
208 FindPrimaryVertex(&trkArrayOrig,idOrig);
210 if(fMode==0) trkArrayOrig.Delete();
211 delete idOrig; idOrig=NULL;
214 f->Close(); delete f; f = NULL;
215 gSystem->Unlink("VertexerTracks.root");
219 // set vertex ID for tracks used in the fit
222 Int_t nIndices = fCurrentVertex->GetNIndices();
223 UShort_t *indices = fCurrentVertex->GetIndices();
224 for(Int_t ind=0; ind<nIndices; ind++) {
225 AliESDtrack *esdt = (AliESDtrack*)vEvent->GetTrack(indices[ind]);
226 esdt->SetVertexID(-1);
230 return fCurrentVertex;
232 //----------------------------------------------------------------------------
233 AliESDVertex* AliVertexerTracks::FindPrimaryVertex(TObjArray *trkArrayOrig,
237 // Primary vertex using the AliExternalTrackParam's in the TObjArray.
238 // idOrig must contain the track IDs from AliESDtrack::GetID()
240 // 1st with 5*fNSigma*sigma cut w.r.t. to initial vertex
241 // + cut on sqrt(d0d0+z0z0) if fConstraint=kFALSE
242 // 2nd with fNSigma*sigma cut w.r.t. to vertex found in 1st iteration)
246 // accept 1-track case only if constraint is available
247 if(!fConstraint && fMinTracks==1) fMinTracks=2;
249 // read tracks from array
250 Int_t nTrksOrig = (Int_t)trkArrayOrig->GetEntriesFast();
251 AliDebug(1,Form("Initial number of tracks: %d",nTrksOrig));
252 if(nTrksOrig<fMinTracks) {
253 AliDebug(1,"TooFewTracks");
255 return fCurrentVertex;
258 // If fConstraint=kFALSE
259 // run VertexFinder(1) to get rough estimate of initVertex (x,y)
261 // fill fTrkArraySel, for VertexFinder()
262 fIdSel = new UShort_t[nTrksOrig];
263 PrepareTracks(*trkArrayOrig,idOrig,0);
264 if(fIdSel) { delete fIdSel; fIdSel=NULL; }
265 Double_t cutsave = fDCAcut;
266 fDCAcut = fDCAcutIter0;
268 switch (fAlgoIter0) {
269 case 1: StrLinVertexFinderMinDist(1); break;
270 case 2: StrLinVertexFinderMinDist(0); break;
271 case 3: HelixVertexFinder(); break;
272 case 4: VertexFinder(1); break;
273 case 5: VertexFinder(0); break;
274 default: printf("Wrong algorithm\n"); break;
277 if(fVert.GetNContributors()>0) {
278 fVert.GetXYZ(fNominalPos);
279 fNominalPos[0] = fVert.GetXv();
280 fNominalPos[1] = fVert.GetYv();
281 fNominalPos[2] = fVert.GetZv();
282 AliDebug(1,Form("No mean vertex: VertexFinder gives (%f, %f, %f)",fNominalPos[0],fNominalPos[1],fNominalPos[2]));
287 AliDebug(1,"No mean vertex and VertexFinder failed");
294 // propagate tracks to fNominalPos vertex
296 // if(constraint) reject for |d0|>5*fNSigma*sigma w.r.t. fNominal... vertex
297 // else reject for |d0|\oplus|z0| > 5 mm w.r.t. fNominal... vertex
299 // propagate tracks to best between initVertex and fCurrentVertex
300 // preselect tracks (reject for |d0|>fNSigma*sigma w.r.t. best
301 // between initVertex and fCurrentVertex)
302 for(Int_t iter=1; iter<=2; iter++) {
303 if(fOnlyFitter && iter==1) continue;
304 if(fIdSel) { delete fIdSel; fIdSel=NULL; }
305 fIdSel = new UShort_t[nTrksOrig];
306 Int_t nTrksSel = PrepareTracks(*trkArrayOrig,idOrig,iter);
307 AliDebug(1,Form("N tracks selected in iteration %d: %d",iter,nTrksSel));
308 if(nTrksSel < fMinTracks) {
310 return fCurrentVertex;
316 AliDebug(1,"Just one track");
317 OneTrackVertFinder();
320 case 1: StrLinVertexFinderMinDist(1); break;
321 case 2: StrLinVertexFinderMinDist(0); break;
322 case 3: HelixVertexFinder(); break;
323 case 4: VertexFinder(1); break;
324 case 5: VertexFinder(0); break;
325 default: printf("Wrong algorithm"); break;
328 AliDebug(1," Vertex finding completed");
333 } // end loop on the two iterations
336 // set indices of used tracks
337 UShort_t *indices = 0;
338 if(fCurrentVertex->GetNContributors()>0) {
339 Int_t nIndices = (Int_t)fTrkArraySel.GetEntriesFast();
340 indices = new UShort_t[nIndices];
341 for(Int_t jj=0; jj<nIndices; jj++)
342 indices[jj] = fIdSel[jj];
343 fCurrentVertex->SetIndices(nIndices,indices);
345 if (indices) {delete indices; indices=NULL;}
349 TString title="VertexerTracksNoConstraint";
351 title="VertexerTracksWithConstraint";
352 if(fOnlyFitter) title.Append("OnlyFitter");
354 fCurrentVertex->SetTitle(title.Data());
357 AliDebug(1,Form("xyz: %f %f %f; nc %d",fCurrentVertex->GetXv(),fCurrentVertex->GetYv(),fCurrentVertex->GetZv(),fCurrentVertex->GetNContributors()));
360 delete fIdSel; fIdSel=NULL;
361 fTrkArraySel.Delete();
362 if(fTrksToSkip) { delete fTrksToSkip; fTrksToSkip=NULL; }
365 return fCurrentVertex;
367 //------------------------------------------------------------------------
368 Double_t AliVertexerTracks::GetDeterminant3X3(Double_t matr[][3])
371 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];
374 //-------------------------------------------------------------------------
375 void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t (*m)[3],Double_t *d)
378 Double_t x12=p0[0]-p1[0];
379 Double_t y12=p0[1]-p1[1];
380 Double_t z12=p0[2]-p1[2];
381 Double_t kk=x12*x12+y12*y12+z12*z12;
382 m[0][0]=2-2/kk*x12*x12;
383 m[0][1]=-2/kk*x12*y12;
384 m[0][2]=-2/kk*x12*z12;
385 m[1][0]=-2/kk*x12*y12;
386 m[1][1]=2-2/kk*y12*y12;
387 m[1][2]=-2/kk*y12*z12;
388 m[2][0]=-2/kk*x12*z12;
390 m[2][2]=2-2/kk*z12*z12;
391 d[0]=2*p0[0]-2/kk*p0[0]*x12*x12-2/kk*p0[2]*x12*z12-2/kk*p0[1]*x12*y12;
392 d[1]=2*p0[1]-2/kk*p0[1]*y12*y12-2/kk*p0[0]*x12*y12-2/kk*p0[2]*z12*y12;
393 d[2]=2*p0[2]-2/kk*p0[2]*z12*z12-2/kk*p0[0]*x12*z12-2/kk*p0[1]*z12*y12;
396 //--------------------------------------------------------------------------
397 void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t *sigmasq,Double_t (*m)[3],Double_t *d)
400 Double_t x12=p1[0]-p0[0];
401 Double_t y12=p1[1]-p0[1];
402 Double_t z12=p1[2]-p0[2];
404 Double_t den= x12*x12*sigmasq[1]*sigmasq[2]+y12*y12*sigmasq[0]*sigmasq[2]+z12*z12*sigmasq[0]*sigmasq[1];
406 Double_t kk= 2*(x12*x12/sigmasq[0]+y12*y12/sigmasq[1]+z12*z12/sigmasq[2]);
409 cc[0]=-x12/sigmasq[0];
410 cc[1]=-y12/sigmasq[1];
411 cc[2]=-z12/sigmasq[2];
413 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;
415 Double_t ss= -p0[0]*cc[0]-p0[1]*cc[1]-p0[2]*cc[2];
418 aa[0]=x12*sigmasq[1]*sigmasq[2]/den;
419 aa[1]=y12*sigmasq[0]*sigmasq[2]/den;
420 aa[2]=z12*sigmasq[0]*sigmasq[1]/den;
422 m[0][0]=aa[0]*(aa[0]*kk+2*cc[0])+2*cc[0]*aa[0]+2/sigmasq[0];
423 m[0][1]=aa[1]*(aa[0]*kk+2*cc[0])+2*cc[1]*aa[0];
424 m[0][2]=aa[2]*(aa[0]*kk+2*cc[0])+2*cc[2]*aa[0];
426 m[1][0]=aa[0]*(aa[1]*kk+2*cc[1])+2*cc[0]*aa[1];
427 m[1][1]=aa[1]*(aa[1]*kk+2*cc[1])+2*cc[1]*aa[1]+2/sigmasq[1];
428 m[1][2]=aa[2]*(aa[1]*kk+2*cc[1])+2*cc[2]*aa[1];
430 m[2][0]=aa[0]*(aa[2]*kk+2*cc[2])+2*cc[0]*aa[2];
431 m[2][1]=aa[1]*(aa[2]*kk+2*cc[2])+2*cc[1]*aa[2];
432 m[2][2]=aa[2]*(aa[2]*kk+2*cc[2])+2*cc[2]*aa[2]+2/sigmasq[2];
434 d[0]=-ww*(aa[0]*kk+2*cc[0])-2*ss*aa[0]+2*p0[0]/sigmasq[0];
435 d[1]=-ww*(aa[1]*kk+2*cc[1])-2*ss*aa[1]+2*p0[1]/sigmasq[1];
436 d[2]=-ww*(aa[2]*kk+2*cc[2])-2*ss*aa[2]+2*p0[2]/sigmasq[2];
439 //--------------------------------------------------------------------------
440 Double_t AliVertexerTracks::GetStrLinMinDist(Double_t *p0,Double_t *p1,Double_t *x0)
443 Double_t x12=p0[0]-p1[0];
444 Double_t y12=p0[1]-p1[1];
445 Double_t z12=p0[2]-p1[2];
446 Double_t x10=p0[0]-x0[0];
447 Double_t y10=p0[1]-x0[1];
448 Double_t z10=p0[2]-x0[2];
449 // 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);
450 return ((y10*z12-z10*y12)*(y10*z12-z10*y12)+
451 (z10*x12-x10*z12)*(z10*x12-x10*z12)+
452 (x10*y12-y10*x12)*(x10*y12-y10*x12))
453 /(x12*x12+y12*y12+z12*z12);
455 //---------------------------------------------------------------------------
456 void AliVertexerTracks::OneTrackVertFinder()
458 // find vertex for events with 1 track, using DCA to nominal beam axis
459 AliDebug(1,Form("Number of prepared tracks =%d - Call OneTrackVertFinder",fTrkArraySel.GetEntries()));
460 AliExternalTrackParam *track1;
461 track1 = (AliExternalTrackParam*)fTrkArraySel.At(0);
462 Double_t alpha=track1->GetAlpha();
463 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
464 Double_t pos[3],dir[3];
465 track1->GetXYZAt(mindist,GetFieldkG(),pos);
466 track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
467 AliStrLine *line1 = new AliStrLine(pos,dir);
468 Double_t p1[3]={fNominalPos[0],fNominalPos[1],0.};
469 Double_t p2[3]={fNominalPos[0],fNominalPos[1],10.};
470 AliStrLine *zeta=new AliStrLine(p1,p2,kTRUE);
471 Double_t crosspoint[3]={0.,0.,0.};
474 Int_t retcode = zeta->Cross(line1,crosspoint);
476 sigma=line1->GetDistFromPoint(crosspoint);
481 fVert.SetXYZ(crosspoint);
482 fVert.SetDispersion(sigma);
483 fVert.SetNContributors(nContrib);
485 //---------------------------------------------------------------------------
486 void AliVertexerTracks::HelixVertexFinder()
488 // Get estimate of vertex position in (x,y) from tracks DCA
493 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
495 Int_t nacc = (Int_t)fTrkArraySel.GetEntriesFast();
497 Double_t aver[3]={0.,0.,0.};
498 Double_t averquad[3]={0.,0.,0.};
499 Double_t sigmaquad[3]={0.,0.,0.};
502 AliExternalTrackParam *track1;
503 AliExternalTrackParam *track2;
506 Double_t alpha, cs, sn;
507 Double_t crosspoint[3];
508 for(Int_t i=0; i<nacc; i++){
509 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
512 for(Int_t j=i+1; j<nacc; j++){
513 track2 = (AliExternalTrackParam*)fTrkArraySel.At(j);
515 distCA=track2->PropagateToDCA(track1,GetFieldkG());
516 if(fDCAcut<=0 ||(fDCAcut>0&&distCA<fDCAcut)){
518 alpha=track1->GetAlpha();
519 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
520 Double_t x1=x*cs - track1->GetY()*sn;
521 Double_t y1=x*sn + track1->GetY()*cs;
522 Double_t z1=track1->GetZ();
524 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
526 alpha=track2->GetAlpha();
527 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
528 Double_t x2=x*cs - track2->GetY()*sn;
529 Double_t y2=x*sn + track2->GetY()*cs;
530 Double_t z2=track2->GetZ();
531 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
532 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
533 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
534 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
535 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
536 crosspoint[0]=wx1*x1 + wx2*x2;
537 crosspoint[1]=wy1*y1 + wy2*y2;
538 crosspoint[2]=wz1*z1 + wz2*z2;
541 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
542 for(Int_t jj=0;jj<3;jj++)averquad[jj]+=(crosspoint[jj]*crosspoint[jj]);
548 for(Int_t jj=0;jj<3;jj++){
549 initPos[jj] = aver[jj]/ncombi;
550 averquad[jj]/=ncombi;
551 sigmaquad[jj]=averquad[jj]-initPos[jj]*initPos[jj];
552 sigma+=sigmaquad[jj];
554 sigma=TMath::Sqrt(TMath::Abs(sigma));
557 Warning("HelixVertexFinder","Finder did not succed");
560 fVert.SetXYZ(initPos);
561 fVert.SetDispersion(sigma);
562 fVert.SetNContributors(ncombi);
564 //----------------------------------------------------------------------------
565 Int_t AliVertexerTracks::PrepareTracks(TObjArray &trkArrayOrig,
570 // Propagate tracks to initial vertex position and store them in a TObjArray
572 AliDebug(1," PrepareTracks()");
574 Int_t nTrksOrig = (Int_t)trkArrayOrig.GetEntriesFast();
577 Double_t sigmaCurr[3];
578 Double_t normdistx,normdisty;
579 Double_t d0z0[2],covd0z0[3];
582 AliESDVertex *initVertex = new AliESDVertex(fNominalPos,fNominalCov,1,1);
584 if(!fTrkArraySel.IsEmpty()) fTrkArraySel.Delete();
586 AliExternalTrackParam *track=0;
589 for(Int_t i=0; i<nTrksOrig; i++) {
590 AliExternalTrackParam *trackOrig=(AliExternalTrackParam*)trkArrayOrig.At(i);
591 if(trackOrig->Charge()!=0) { // normal tracks
592 track = new AliExternalTrackParam(*(AliExternalTrackParam*)trkArrayOrig.At(i));
593 } else { // neutral tracks (from a V0)
594 track = new AliNeutralTrackParam(*(AliNeutralTrackParam*)trkArrayOrig.At(i));
598 if(TMath::Abs(track->GetTgl())>fMaxTgl) {
599 AliDebug(1,Form(" rejecting track with tgl = %f",track->GetTgl()));
600 delete track; continue;
603 Bool_t propagateOK = kFALSE;
604 // propagate track to vertex
605 if(optImpParCut<2 || fOnlyFitter) { // optImpParCut==1 or 0
606 propagateOK = track->PropagateToDCA(initVertex,GetFieldkG(),100.,d0z0,covd0z0);
607 } else { // optImpParCut==2
608 fCurrentVertex->GetSigmaXYZ(sigmaCurr);
609 normdistx = TMath::Abs(fCurrentVertex->GetXv()-fNominalPos[0])/TMath::Sqrt(sigmaCurr[0]*sigmaCurr[0]+fNominalCov[0]);
610 normdisty = TMath::Abs(fCurrentVertex->GetYv()-fNominalPos[1])/TMath::Sqrt(sigmaCurr[1]*sigmaCurr[1]+fNominalCov[2]);
611 if(normdistx < 3. && normdisty < 3. &&
612 (sigmaCurr[0]+sigmaCurr[1])<(TMath::Sqrt(fNominalCov[0])+TMath::Sqrt(fNominalCov[2]))) {
613 propagateOK = track->PropagateToDCA(fCurrentVertex,GetFieldkG(),100.,d0z0,covd0z0);
615 propagateOK = track->PropagateToDCA(initVertex,GetFieldkG(),100.,d0z0,covd0z0);
620 AliDebug(1," rejected");
621 delete track; continue;
624 sigmad0 = TMath::Sqrt(covd0z0[0]);
625 maxd0rphi = fNSigma*sigmad0;
626 if(optImpParCut==1) maxd0rphi *= 5.;
627 maxd0rphi = TMath::Min(maxd0rphi,fFiducialR);
628 //sigmad0z0 = TMath::Sqrt(covd0z0[0]+covd0z0[2]); // for future improvement
629 //maxd0z0 = 10.*fNSigma*sigmad0z0;
631 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));
634 //---- track selection based on impact parameters ----//
636 // always reject tracks outside fiducial volume
637 if(TMath::Abs(d0z0[0])>fFiducialR || TMath::Abs(d0z0[1])>fFiducialZ) {
638 AliDebug(1," rejected");
639 delete track; continue;
642 // during iterations 1 and 2 , reject tracks with d0rphi > maxd0rphi
643 if(optImpParCut>0 && TMath::Abs(d0z0[0])>maxd0rphi) {
644 AliDebug(1," rejected");
645 delete track; continue;
648 // if fConstraint=kFALSE, during iterations 1 and 2 ||
649 // if fConstraint=kTRUE, during iteration 2,
650 // select tracks with d0oplusz0 < fMaxd0z0
651 if((!fConstraint && optImpParCut>0 && fVert.GetNContributors()>0) ||
652 ( fConstraint && optImpParCut==2)) {
654 TMath::Sqrt(d0z0[0]*d0z0[0]+d0z0[1]*d0z0[1])>fMaxd0z0) {
655 AliDebug(1," rejected");
656 delete track; continue;
660 // track passed all selections
661 fTrkArraySel.AddLast(track);
662 fIdSel[nTrksSel] = idOrig[i];
664 } // end loop on tracks
670 //----------------------------------------------------------------------------
671 Bool_t AliVertexerTracks::PropagateTrackTo(AliExternalTrackParam *track,
673 //----------------------------------------------------------------
674 // COPIED from AliTracker
676 // Propagates the track to the plane X=xk (cm).
678 // Origin: Marian Ivanov, Marian.Ivanov@cern.ch
679 //----------------------------------------------------------------
681 const Double_t kEpsilon = 0.00001;
682 Double_t xpos = track->GetX();
683 Double_t dir = (xpos<xToGo) ? 1. : -1.;
684 Double_t maxStep = 5;
685 Double_t maxSnp = 0.8;
687 while ( (xToGo-xpos)*dir > kEpsilon){
688 Double_t step = dir*TMath::Min(TMath::Abs(xToGo-xpos), maxStep);
689 Double_t x = xpos+step;
690 Double_t xyz0[3],xyz1[3];
691 track->GetXYZ(xyz0); //starting global position
693 if(!track->GetXYZAt(x,GetFieldkG(),xyz1)) return kFALSE; // no prolongation
694 xyz1[2]+=kEpsilon; // waiting for bug correction in geo
696 if(TMath::Abs(track->GetSnpAt(x,GetFieldkG())) >= maxSnp) return kFALSE;
697 if(!track->PropagateTo(x,GetFieldkG())) return kFALSE;
699 if(TMath::Abs(track->GetSnp()) >= maxSnp) return kFALSE;
700 track->GetXYZ(xyz0); // global position
701 Double_t alphan = TMath::ATan2(xyz0[1], xyz0[0]);
703 Double_t ca=TMath::Cos(alphan-track->GetAlpha()),
704 sa=TMath::Sin(alphan-track->GetAlpha());
705 Double_t sf=track->GetSnp(), cf=TMath::Sqrt((1.-sf)*(1.+sf));
706 Double_t sinNew = sf*ca - cf*sa;
707 if(TMath::Abs(sinNew) >= maxSnp) return kFALSE;
708 if(!track->Rotate(alphan)) return kFALSE;
710 xpos = track->GetX();
714 //---------------------------------------------------------------------------
715 AliESDVertex* AliVertexerTracks::RemoveTracksFromVertex(AliESDVertex *inVtx,
721 // Removes tracks in trksTree from fit of inVtx
724 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraint")) {
725 printf("ERROR: primary vertex has no constraint: cannot remove tracks");
728 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraintOnlyFitter"))
729 printf("WARNING: result of tracks' removal will be only approximately correct");
732 rv(0,0) = inVtx->GetXv();
733 rv(1,0) = inVtx->GetYv();
734 rv(2,0) = inVtx->GetZv();
737 inVtx->GetCovMatrix(cov);
739 vV(0,1) = cov[1]; vV(1,0) = cov[1];
741 vV(0,2) = cov[3]; vV(2,0) = cov[3];
742 vV(1,2) = cov[4]; vV(2,1) = cov[4];
745 TMatrixD sumWi(TMatrixD::kInverted,vV);
746 TMatrixD sumWiri(sumWi,TMatrixD::kMult,rv);
748 Int_t nUsedTrks = inVtx->GetNIndices();
749 Double_t chi2 = inVtx->GetChi2();
751 AliExternalTrackParam *track = 0;
752 Int_t ntrks = (Int_t)trkArray->GetEntriesFast();
753 for(Int_t i=0;i<ntrks;i++) {
754 track = (AliExternalTrackParam*)trkArray->At(i);
755 if(!inVtx->UsesTrack(id[i])) {
756 printf("track %d was not used in vertex fit",id[i]);
759 Double_t alpha = track->GetAlpha();
760 Double_t xl = diamondxy[0]*TMath::Cos(alpha)+diamondxy[1]*TMath::Sin(alpha);
761 track->PropagateTo(xl,GetFieldkG());
762 // vector of track global coordinates
764 // covariance matrix of ri
767 // get space point from track
768 if(!TrackToPoint(track,ri,wWi)) continue;
770 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
776 TMatrixD deltar = rv; deltar -= ri;
777 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
778 Double_t chi2i = deltar(0,0)*wWideltar(0,0)+
779 deltar(1,0)*wWideltar(1,0)+
780 deltar(2,0)*wWideltar(2,0);
781 // remove from total chi2
786 printf("Trying to remove too many tracks!");
794 // new inverted of weights matrix
795 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
797 // new position of primary vertex
798 rvnew.Mult(vVnew,sumWiri);
800 Double_t position[3];
801 position[0] = rvnew(0,0);
802 position[1] = rvnew(1,0);
803 position[2] = rvnew(2,0);
811 // store data in the vertex object
812 AliESDVertex *outVtx = new AliESDVertex(position,cov,chi2,nUsedTrks);
813 outVtx->SetTitle(inVtx->GetTitle());
814 UShort_t *inindices = inVtx->GetIndices();
815 Int_t nIndices = nUsedTrks;
816 UShort_t *outindices = new UShort_t[nIndices];
818 for(Int_t k=0; k<inVtx->GetNIndices(); k++) {
819 Bool_t copyindex=kTRUE;
820 for(Int_t l=0; l<ntrks; l++) {
821 if(inindices[k]==id[l]) copyindex=kFALSE;
824 outindices[j] = inindices[k]; j++;
827 outVtx->SetIndices(nIndices,outindices);
828 if (outindices) delete outindices;
831 printf("Vertex before removing tracks:");
832 inVtx->PrintStatus();
833 inVtx->PrintIndices();
834 printf("Vertex after removing tracks:");
835 outVtx->PrintStatus();
836 outVtx->PrintIndices();
841 //---------------------------------------------------------------------------
842 void AliVertexerTracks::SetCuts(Double_t *cuts)
848 SetDCAcutIter0(cuts[1]);
850 if(fMode==0 && cuts[3]<0) SetITSrefitNotRequired();
851 SetMinClusters((Int_t)(TMath::Abs(cuts[3])));
852 SetMinTracks((Int_t)(cuts[4]));
853 SetNSigmad0(cuts[5]);
854 SetMinDetFitter(cuts[6]);
856 SetFiducialRZ(cuts[8],cuts[9]);
857 fAlgo=(Int_t)(cuts[10]);
858 fAlgoIter0=(Int_t)(cuts[11]);
862 //---------------------------------------------------------------------------
863 void AliVertexerTracks::SetITSMode(Double_t dcacut,
864 Double_t dcacutIter0,
869 Double_t mindetfitter,
874 Int_t finderAlgoIter0)
877 // Cut values for ITS mode
881 SetITSrefitRequired();
883 SetITSrefitNotRequired();
886 SetDCAcutIter0(dcacutIter0);
888 SetMinClusters(TMath::Abs(minCls));
889 SetMinTracks(mintrks);
891 SetMinDetFitter(mindetfitter);
893 SetFiducialRZ(fidR,fidZ);
895 fAlgoIter0=finderAlgoIter0;
899 //---------------------------------------------------------------------------
900 void AliVertexerTracks::SetTPCMode(Double_t dcacut,
901 Double_t dcacutIter0,
906 Double_t mindetfitter,
911 Int_t finderAlgoIter0)
914 // Cut values for TPC mode
917 SetITSrefitNotRequired();
919 SetDCAcutIter0(dcacutIter0);
921 SetMinClusters(minCls);
922 SetMinTracks(mintrks);
924 SetMinDetFitter(mindetfitter);
926 SetFiducialRZ(fidR,fidZ);
928 fAlgoIter0=finderAlgoIter0;
932 //---------------------------------------------------------------------------
933 void AliVertexerTracks::SetSkipTracks(Int_t n,Int_t *skipped)
936 // Mark the tracks not to be used in the vertex reconstruction.
937 // Tracks are identified by AliESDtrack::GetID()
939 fNTrksToSkip = n; fTrksToSkip = new Int_t[n];
940 for(Int_t i=0;i<n;i++) fTrksToSkip[i] = skipped[i];
943 //---------------------------------------------------------------------------
944 void AliVertexerTracks::SetVtxStart(AliESDVertex *vtx)
947 // Set initial vertex knowledge
949 vtx->GetXYZ(fNominalPos);
950 vtx->GetCovMatrix(fNominalCov);
954 //---------------------------------------------------------------------------
955 void AliVertexerTracks::StrLinVertexFinderMinDist(Int_t optUseWeights)
957 AliExternalTrackParam *track1;
958 const Int_t knacc = (Int_t)fTrkArraySel.GetEntriesFast();
959 AliStrLine **linarray = new AliStrLine* [knacc];
960 for(Int_t i=0; i<knacc; i++){
961 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
962 Double_t alpha=track1->GetAlpha();
963 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
964 Double_t pos[3],dir[3],sigmasq[3];
965 track1->GetXYZAt(mindist,GetFieldkG(),pos);
966 track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
967 sigmasq[0]=TMath::Sin(alpha)*TMath::Sin(alpha)*track1->GetSigmaY2();
968 sigmasq[1]=TMath::Cos(alpha)*TMath::Cos(alpha)*track1->GetSigmaY2();
969 sigmasq[2]=track1->GetSigmaZ2();
972 if(!TrackToPoint(track1,ri,wWi)) {optUseWeights=kFALSE;printf("WARNING\n");}
975 for(Int_t ia=0;ia<3;ia++){
976 for(Int_t ib=0;ib<3;ib++){
977 wmat[iel]=wWi(ia,ib);
981 linarray[i] = new AliStrLine(pos,sigmasq,wmat,dir);
983 fVert=TrackletVertexFinder(linarray,knacc,optUseWeights);
984 for(Int_t i=0; i<knacc; i++) delete linarray[i];
987 //---------------------------------------------------------------------------
988 AliESDVertex AliVertexerTracks::TrackletVertexFinder(TClonesArray *lines, Int_t optUseWeights)
990 // Calculate the point at minimum distance to prepared tracks (TClonesArray)
991 const Int_t knacc = (Int_t)lines->GetEntriesFast();
992 AliStrLine** lines2 = new AliStrLine* [knacc];
993 for(Int_t i=0; i<knacc; i++){
994 lines2[i]= (AliStrLine*)lines->At(i);
996 AliESDVertex vert = TrackletVertexFinder(lines2,knacc,optUseWeights);
1001 //---------------------------------------------------------------------------
1002 AliESDVertex AliVertexerTracks::TrackletVertexFinder(AliStrLine **lines, const Int_t knacc, Int_t optUseWeights)
1004 // Calculate the point at minimum distance to prepared tracks (array of AliStrLine)
1006 Double_t initPos[3]={0.,0.,0.};
1008 Double_t (*vectP0)[3]=new Double_t [knacc][3];
1009 Double_t (*vectP1)[3]=new Double_t [knacc][3];
1012 Double_t dsum[3]={0,0,0};
1013 TMatrixD sumWi(3,3);
1014 for(Int_t i=0;i<3;i++){
1015 for(Int_t j=0;j<3;j++){
1021 for(Int_t i=0; i<knacc; i++){
1022 AliStrLine *line1 = lines[i];
1023 Double_t p0[3],cd[3],sigmasq[3];
1025 if(!line1) printf("ERROR %d %d\n",i,knacc);
1028 line1->GetSigma2P0(sigmasq);
1029 line1->GetWMatrix(wmat);
1032 for(Int_t ia=0;ia<3;ia++){
1033 for(Int_t ib=0;ib<3;ib++){
1034 wWi(ia,ib)=wmat[iel];
1041 Double_t p1[3]={p0[0]+cd[0],p0[1]+cd[1],p0[2]+cd[2]};
1049 Double_t matr[3][3];
1051 if(optUseWeights==0)GetStrLinDerivMatrix(p0,p1,matr,dknow);
1052 else GetStrLinDerivMatrix(p0,p1,sigmasq,matr,dknow);
1055 for(Int_t iii=0;iii<3;iii++){
1056 dsum[iii]+=dknow[iii];
1057 for(Int_t lj=0;lj<3;lj++) sum[iii][lj]+=matr[iii][lj];
1061 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
1062 Double_t covmatrix[6];
1063 covmatrix[0] = invsumWi(0,0);
1064 covmatrix[1] = invsumWi(0,1);
1065 covmatrix[2] = invsumWi(1,1);
1066 covmatrix[3] = invsumWi(0,2);
1067 covmatrix[4] = invsumWi(1,2);
1068 covmatrix[5] = invsumWi(2,2);
1070 Double_t vett[3][3];
1071 Double_t det=GetDeterminant3X3(sum);
1075 for(Int_t zz=0;zz<3;zz++){
1076 for(Int_t ww=0;ww<3;ww++){
1077 for(Int_t kk=0;kk<3;kk++) vett[ww][kk]=sum[ww][kk];
1079 for(Int_t kk=0;kk<3;kk++) vett[kk][zz]=dsum[kk];
1080 initPos[zz]=GetDeterminant3X3(vett)/det;
1084 for(Int_t i=0; i<knacc; i++){
1085 Double_t p0[3]={0,0,0},p1[3]={0,0,0};
1086 for(Int_t ii=0;ii<3;ii++){
1087 p0[ii]=vectP0[i][ii];
1088 p1[ii]=vectP1[i][ii];
1090 sigma+=GetStrLinMinDist(p0,p1,initPos);
1093 if(sigma>0.) {sigma=TMath::Sqrt(sigma);}else{sigma=999;}
1097 AliESDVertex theVert(initPos,covmatrix,99999.,knacc);
1098 theVert.SetDispersion(sigma);
1104 //---------------------------------------------------------------------------
1105 Bool_t AliVertexerTracks::TrackToPoint(AliExternalTrackParam *t,
1106 TMatrixD &ri,TMatrixD &wWi,
1107 Bool_t uUi3by3) const
1110 // Extract from the AliExternalTrackParam the global coordinates ri and covariance matrix
1111 // wWi of the space point that it represents (to be used in VertexFitter())
1115 Double_t rotAngle = t->GetAlpha();
1116 if(rotAngle<0.) rotAngle += 2.*TMath::Pi();
1117 Double_t cosRot = TMath::Cos(rotAngle);
1118 Double_t sinRot = TMath::Sin(rotAngle);
1120 ri(0,0) = t->GetX()*cosRot-t->GetY()*sinRot;
1121 ri(1,0) = t->GetX()*sinRot+t->GetY()*cosRot;
1122 ri(2,0) = t->GetZ();
1127 // matrix to go from global (x,y,z) to local (y,z);
1136 // covariance matrix of local (y,z) - inverted
1138 uUi(0,0) = t->GetSigmaY2();
1139 uUi(0,1) = t->GetSigmaZY();
1140 uUi(1,0) = t->GetSigmaZY();
1141 uUi(1,1) = t->GetSigmaZ2();
1143 //printf(" %f %f",uUi(0,0),uUi(0,1));
1144 //printf(" %f %f",uUi(1,0),uUi(1,1));
1146 if(uUi.Determinant() <= 0.) return kFALSE;
1147 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
1149 // weights matrix: wWi = qQiT * uUiInv * qQi
1150 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
1151 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
1154 if(fVert.GetNContributors()<1) AliFatal("Vertex from finder is empty");
1155 // matrix to go from global (x,y,z) to local (x,y,z);
1167 // covariance of fVert along the track
1168 Double_t p[3],pt,ptot;
1170 pt = TMath::Sqrt(p[0]*p[0]+p[1]*p[1]);
1171 ptot = TMath::Sqrt(pt*pt+p[2]*p[2]);
1172 Double_t cphi = p[0]/pt; //cos(phi)=px/pt
1173 Double_t sphi = p[1]/pt; //sin(phi)=py/pt
1174 Double_t clambda = pt/ptot; //cos(lambda)=pt/ptot
1175 Double_t slambda = p[2]/ptot; //sin(lambda)=pz/ptot
1176 Double_t covfVert[6];
1177 fVert.GetCovMatrix(covfVert);
1178 Double_t covfVertalongt =
1179 covfVert[0]*cphi*cphi*clambda*clambda
1180 +covfVert[1]*2.*cphi*sphi*clambda*clambda
1181 +covfVert[3]*2.*cphi*clambda*slambda
1182 +covfVert[2]*sphi*sphi*clambda*clambda
1183 +covfVert[4]*2.*sphi*clambda*slambda
1184 +covfVert[5]*slambda*slambda;
1185 // covariance matrix of local (x,y,z) - inverted
1187 uUi(0,0) = covfVertalongt * fnSigmaForUi00 * fnSigmaForUi00;
1188 AliDebug(1,Form("=====> sqrtUi00 cm %f",TMath::Sqrt(uUi(0,0))));
1192 uUi(1,1) = t->GetSigmaY2();
1193 uUi(1,2) = t->GetSigmaZY();
1195 uUi(2,1) = t->GetSigmaZY();
1196 uUi(2,2) = t->GetSigmaZ2();
1197 //printf(" Ui :\n");
1198 //printf(" %f %f\n",uUi(0,0),uUi(0,1));
1199 //printf(" %f %f\n",uUi(1,0),uUi(1,1));
1201 if(uUi.Determinant() <= 0.) return kFALSE;
1202 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
1204 // weights matrix: wWi = qQiT * uUiInv * qQi
1205 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
1206 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
1213 //---------------------------------------------------------------------------
1214 void AliVertexerTracks::TooFewTracks()
1217 // When the number of tracks is < fMinTracks,
1218 // deal with vertices not found and prepare to exit
1220 AliDebug(1,"TooFewTracks");
1222 Double_t pos[3],err[3];
1223 pos[0] = fNominalPos[0];
1224 err[0] = TMath::Sqrt(fNominalCov[0]);
1225 pos[1] = fNominalPos[1];
1226 err[1] = TMath::Sqrt(fNominalCov[2]);
1227 pos[2] = fNominalPos[2];
1228 err[2] = TMath::Sqrt(fNominalCov[5]);
1229 Int_t ncontr = (err[0]>1. ? -1 : -3);
1230 if(fCurrentVertex) { delete fCurrentVertex; fCurrentVertex=0; }
1231 fCurrentVertex = new AliESDVertex(pos,err);
1232 fCurrentVertex->SetNContributors(ncontr);
1235 fCurrentVertex->SetTitle("VertexerTracksWithConstraint");
1237 fCurrentVertex->SetTitle("VertexerTracksNoConstraint");
1240 if(!fTrkArraySel.IsEmpty()) fTrkArraySel.Delete();
1241 if(fIdSel) {delete fIdSel; fIdSel=NULL;}
1242 if(fTrksToSkip) {delete fTrksToSkip; fTrksToSkip=NULL;}
1246 //---------------------------------------------------------------------------
1247 void AliVertexerTracks::VertexFinder(Int_t optUseWeights)
1250 // Get estimate of vertex position in (x,y) from tracks DCA
1252 Double_t initPos[3];
1254 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
1255 Int_t nacc = (Int_t)fTrkArraySel.GetEntriesFast();
1256 Double_t aver[3]={0.,0.,0.};
1257 Double_t aversq[3]={0.,0.,0.};
1258 Double_t sigmasq[3]={0.,0.,0.};
1261 AliExternalTrackParam *track1;
1262 AliExternalTrackParam *track2;
1263 Double_t pos[3],dir[3];
1264 Double_t alpha,mindist;
1266 for(Int_t i=0; i<nacc; i++){
1267 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
1268 alpha=track1->GetAlpha();
1269 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1270 track1->GetXYZAt(mindist,GetFieldkG(),pos);
1271 track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
1272 AliStrLine *line1 = new AliStrLine(pos,dir);
1274 // AliStrLine *line1 = new AliStrLine();
1275 // track1->ApproximateHelixWithLine(mindist,GetFieldkG(),line1);
1277 for(Int_t j=i+1; j<nacc; j++){
1278 track2 = (AliExternalTrackParam*)fTrkArraySel.At(j);
1279 alpha=track2->GetAlpha();
1280 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1281 track2->GetXYZAt(mindist,GetFieldkG(),pos);
1282 track2->GetPxPyPzAt(mindist,GetFieldkG(),dir);
1283 AliStrLine *line2 = new AliStrLine(pos,dir);
1284 // AliStrLine *line2 = new AliStrLine();
1285 // track2->ApproximateHelixWithLine(mindist,GetFieldkG(),line2);
1286 Double_t distCA=line2->GetDCA(line1);
1287 //printf("%d %d %f\n",i,j,distCA);
1288 if(fDCAcut<=0 || (fDCAcut>0&&distCA<fDCAcut)){
1289 Double_t pnt1[3],pnt2[3],crosspoint[3];
1291 if(optUseWeights<=0){
1292 Int_t retcode = line2->Cross(line1,crosspoint);
1295 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
1296 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1299 if(optUseWeights>0){
1300 Int_t retcode = line1->CrossPoints(line2,pnt1,pnt2);
1303 alpha=track1->GetAlpha();
1304 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
1305 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
1306 alpha=track2->GetAlpha();
1307 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
1308 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
1309 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
1310 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
1311 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
1312 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
1313 crosspoint[0]=wx1*pnt1[0] + wx2*pnt2[0];
1314 crosspoint[1]=wy1*pnt1[1] + wy2*pnt2[1];
1315 crosspoint[2]=wz1*pnt1[2] + wz2*pnt2[2];
1318 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
1319 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1328 for(Int_t jj=0;jj<3;jj++){
1329 initPos[jj] = aver[jj]/ncombi;
1330 //printf("%f\n",initPos[jj]);
1332 sigmasq[jj]=aversq[jj]-initPos[jj]*initPos[jj];
1335 sigma=TMath::Sqrt(TMath::Abs(sigma));
1338 Warning("VertexFinder","Finder did not succed");
1341 fVert.SetXYZ(initPos);
1342 fVert.SetDispersion(sigma);
1343 fVert.SetNContributors(ncombi);
1345 //---------------------------------------------------------------------------
1346 void AliVertexerTracks::VertexFitter()
1349 // The optimal estimate of the vertex position is given by a "weighted
1350 // average of tracks positions".
1351 // Original method: V. Karimaki, CMS Note 97/0051
1353 Bool_t useConstraint = fConstraint;
1354 Double_t initPos[3];
1356 fVert.GetXYZ(initPos);
1358 initPos[0]=fNominalPos[0];
1359 initPos[1]=fNominalPos[1];
1360 initPos[2]=fNominalPos[2];
1363 Int_t nTrksSel = (Int_t)fTrkArraySel.GetEntries();
1364 if(nTrksSel==1) useConstraint=kTRUE;
1365 AliDebug(1,"--- VertexFitter(): start");
1366 AliDebug(1,Form(" Number of tracks in array: %d\n",nTrksSel));
1367 AliDebug(1,Form(" Minimum # tracks required in fit: %d\n",fMinTracks));
1368 AliDebug(1,Form(" Vertex position after finder: %f,%f,%f\n",initPos[0],initPos[1],initPos[2]));
1369 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])));
1371 // special treatment for few-tracks fits (e.g. secondary vertices)
1372 Bool_t uUi3by3 = kFALSE; if(nTrksSel<5 && !useConstraint) uUi3by3 = kTRUE;
1377 rv(0,0) = initPos[0];
1378 rv(1,0) = initPos[1];
1380 Double_t xlStart,alpha;
1382 Double_t chi2,chi2i,chi2b;
1383 AliExternalTrackParam *t = 0;
1386 // initial vertex covariance matrix
1388 vVb(0,0) = fNominalCov[0];
1389 vVb(0,1) = fNominalCov[1];
1391 vVb(1,0) = fNominalCov[1];
1392 vVb(1,1) = fNominalCov[2];
1396 vVb(2,2) = fNominalCov[5];
1397 TMatrixD vVbInv(TMatrixD::kInverted,vVb);
1399 rb(0,0) = fNominalPos[0];
1400 rb(1,0) = fNominalPos[1];
1401 rb(2,0) = fNominalPos[2];
1402 TMatrixD vVbInvrb(vVbInv,TMatrixD::kMult,rb);
1406 // 1st - estimate of vtx using all tracks
1407 // 2nd - estimate of global chi2
1408 for(step=0; step<2; step++) {
1409 AliDebug(1,Form(" step = %d\n",step));
1413 if(step==1) { initPos[0]=rv(0,0); initPos[0]=rv(1,0); }
1415 TMatrixD sumWiri(3,1);
1416 TMatrixD sumWi(3,3);
1417 for(i=0; i<3; i++) {
1419 for(j=0; j<3; j++) sumWi(j,i) = 0.;
1422 // mean vertex constraint
1425 sumWiri(i,0) += vVbInvrb(i,0);
1426 for(k=0;k<3;k++) sumWi(i,k) += vVbInv(i,k);
1429 TMatrixD deltar = rv; deltar -= rb;
1430 TMatrixD vVbInvdeltar(vVbInv,TMatrixD::kMult,deltar);
1431 chi2b = deltar(0,0)*vVbInvdeltar(0,0)+
1432 deltar(1,0)*vVbInvdeltar(1,0)+
1433 deltar(2,0)*vVbInvdeltar(2,0);
1438 for(k=0; k<nTrksSel; k++) {
1439 // get track from track array
1440 t = (AliExternalTrackParam*)fTrkArraySel.At(k);
1441 alpha = t->GetAlpha();
1442 xlStart = initPos[0]*TMath::Cos(alpha)+initPos[1]*TMath::Sin(alpha);
1443 // to vtxSeed (from finder)
1444 t->PropagateTo(xlStart,GetFieldkG());
1446 // vector of track global coordinates
1448 // covariance matrix of ri
1451 // get space point from track
1452 if(!TrackToPoint(t,ri,wWi,uUi3by3)) continue;
1453 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
1456 TMatrixD deltar = rv; deltar -= ri;
1457 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
1458 chi2i = deltar(0,0)*wWideltar(0,0)+
1459 deltar(1,0)*wWideltar(1,0)+
1460 deltar(2,0)*wWideltar(2,0);
1462 // add to total chi2
1469 } // end loop on tracks
1471 if(nTrksUsed < fMinTracks) {
1476 Double_t determinant = sumWi.Determinant();
1477 if(determinant < fMinDetFitter) {
1478 AliDebug(1,Form("det(V) = %f (<%f)\n",determinant,fMinDetFitter));
1484 // inverted of weights matrix
1485 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
1487 // position of primary vertex
1488 rv.Mult(vV,sumWiri);
1490 } // end loop on the 2 steps
1497 Double_t position[3];
1498 position[0] = rv(0,0);
1499 position[1] = rv(1,0);
1500 position[2] = rv(2,0);
1501 Double_t covmatrix[6];
1502 covmatrix[0] = vV(0,0);
1503 covmatrix[1] = vV(0,1);
1504 covmatrix[2] = vV(1,1);
1505 covmatrix[3] = vV(0,2);
1506 covmatrix[4] = vV(1,2);
1507 covmatrix[5] = vV(2,2);
1509 // for correct chi2/ndf, count constraint as additional "track"
1510 if(fConstraint) nTrksUsed++;
1511 // store data in the vertex object
1512 if(fCurrentVertex) { delete fCurrentVertex; fCurrentVertex=0; }
1513 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nTrksUsed);
1515 AliDebug(1," Vertex after fit:");
1516 AliDebug(1,Form("xyz: %f %f %f; nc %d",fCurrentVertex->GetXv(),fCurrentVertex->GetYv(),fCurrentVertex->GetZv(),fCurrentVertex->GetNContributors()));
1517 AliDebug(1,"--- VertexFitter(): finish\n");
1522 //----------------------------------------------------------------------------
1523 AliESDVertex* AliVertexerTracks::VertexForSelectedTracks(TObjArray *trkArray,
1525 Bool_t optUseFitter,
1526 Bool_t optPropagate)
1529 // Return vertex from tracks (AliExternalTrackParam) in array
1534 // get tracks and propagate them to initial vertex position
1535 fIdSel = new UShort_t[(Int_t)trkArray->GetEntriesFast()];
1536 Int_t nTrksSel = PrepareTracks(*trkArray,id,0);
1537 if(nTrksSel < TMath::Max(2,fMinTracks)) {
1539 return fCurrentVertex;
1544 case 1: StrLinVertexFinderMinDist(1); break;
1545 case 2: StrLinVertexFinderMinDist(0); break;
1546 case 3: HelixVertexFinder(); break;
1547 case 4: VertexFinder(1); break;
1548 case 5: VertexFinder(0); break;
1549 default: printf("Wrong algorithm\n"); break;
1551 AliDebug(1," Vertex finding completed\n");
1557 Double_t position[3]={fVert.GetXv(),fVert.GetYv(),fVert.GetZv()};
1558 Double_t covmatrix[6];
1559 fVert.GetCovMatrix(covmatrix);
1560 Double_t chi2=99999.;
1561 Int_t nTrksUsed=fVert.GetNContributors();
1562 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nTrksUsed);
1564 fCurrentVertex->SetDispersion(fVert.GetDispersion());
1567 // set indices of used tracks and propagate track to found vertex
1568 UShort_t *indices = 0;
1569 Double_t d0z0[2],covd0z0[3];
1570 AliExternalTrackParam *t = 0;
1571 if(fCurrentVertex->GetNContributors()>0) {
1572 indices = new UShort_t[fTrkArraySel.GetEntriesFast()];
1573 for(Int_t jj=0; jj<(Int_t)fTrkArraySel.GetEntriesFast(); jj++) {
1574 indices[jj] = fIdSel[jj];
1575 t = (AliExternalTrackParam*)fTrkArraySel.At(jj);
1576 if(optPropagate && optUseFitter) {
1577 if(TMath::Sqrt(fCurrentVertex->GetXv()*fCurrentVertex->GetXv()+fCurrentVertex->GetYv()*fCurrentVertex->GetYv())<3.) {
1578 t->PropagateToDCA(fCurrentVertex,GetFieldkG(),100.,d0z0,covd0z0);
1579 AliDebug(1,Form("Track %d propagated to found vertex",jj));
1581 AliWarning("Found vertex outside beam pipe!");
1585 fCurrentVertex->SetIndices(fCurrentVertex->GetNContributors(),indices);
1589 if (indices) {delete indices; indices=NULL;}
1590 delete fIdSel; fIdSel=NULL;
1591 fTrkArraySel.Delete();
1593 return fCurrentVertex;
1595 //----------------------------------------------------------------------------
1596 AliESDVertex* AliVertexerTracks::VertexForSelectedESDTracks(TObjArray *trkArray,
1597 Bool_t optUseFitter,
1598 Bool_t optPropagate)
1601 // Return vertex from array of ESD tracks
1604 Int_t nTrks = (Int_t)trkArray->GetEntriesFast();
1605 UShort_t *id = new UShort_t[nTrks];
1607 AliESDtrack *esdt = 0;
1608 for(Int_t i=0; i<nTrks; i++){
1609 esdt = (AliESDtrack*)trkArray->At(i);
1610 id[i] = (UShort_t)esdt->GetID();
1613 VertexForSelectedTracks(trkArray,id,optUseFitter,optPropagate);
1617 return fCurrentVertex;
1619 //--------------------------------------------------------------------------