1 /**************************************************************************
2 * Copyright(c) 1998-2003, ALICE Experiment at CERN, All rights reserved. *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
7 * Permission to use, copy, modify and distribute this software and its *
8 * documentation strictly for non-commercial purposes is hereby granted *
9 * without fee, provided that the above copyright notice appears in all *
10 * copies and that both the copyright notice and this permission notice *
11 * appear in the supporting documentation. The authors make no claims *
12 * about the suitability of this software for any purpose. It is *
13 * provided "as is" without express or implied warranty. *
14 **************************************************************************/
16 //-----------------------------------------------------------------
17 // Implementation of the vertexer from tracks
19 // Origin: AliITSVertexerTracks
21 // andrea.dainese@pd.infn.it
23 // massimo.masera@to.infn.it
24 // Moved to STEER and adapted to ESD tracks:
25 // F.Prino, Torino, prino@to.infn.it
26 //-----------------------------------------------------------------
28 //---- Root headers --------
30 #include <TDirectory.h>
34 //---- AliRoot headers -----
35 #include "AliStrLine.h"
36 #include "AliExternalTrackParam.h"
37 #include "AliESDEvent.h"
38 #include "AliESDtrack.h"
39 #include "AliVertexerTracks.h"
41 ClassImp(AliVertexerTracks)
44 //----------------------------------------------------------------------------
45 AliVertexerTracks::AliVertexerTracks():
73 // Default constructor
78 //----------------------------------------------------------------------------
79 AliVertexerTracks::AliVertexerTracks(Double_t fieldkG):
107 // Standard constructor
113 //-----------------------------------------------------------------------------
114 AliVertexerTracks::~AliVertexerTracks()
116 // Default Destructor
117 // The objects pointed by the following pointer are not owned
118 // by this class and are not deleted
120 if(fTrksToSkip) { delete [] fTrksToSkip; fTrksToSkip=NULL; }
121 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
123 //----------------------------------------------------------------------------
124 AliESDVertex* AliVertexerTracks::FindPrimaryVertex(const AliESDEvent *esdEvent)
127 // Primary vertex for current ESD event
129 // 1st with 5*fNSigma*sigma cut w.r.t. to initial vertex
130 // + cut on sqrt(d0d0+z0z0) if fConstraint=kFALSE
131 // 2nd with fNSigma*sigma cut w.r.t. to vertex found in 1st iteration)
135 // accept 1-track case only if constraint is available
136 if(!fConstraint && fMinTracks==1) fMinTracks=2;
138 // read tracks from ESD
139 Int_t nTrks = (Int_t)esdEvent->GetNumberOfTracks();
140 if(nTrks<fMinTracks) {
142 return fCurrentVertex;
146 TDirectory * olddir = gDirectory;
148 if(nTrks>500) f = new TFile("VertexerTracks.root","recreate");
149 TObjArray trkArrayOrig(nTrks);
150 UShort_t *idOrig = new UShort_t[nTrks];
153 AliExternalTrackParam *t=0;
154 // loop on ESD tracks
155 for(Int_t i=0; i<nTrks; i++) {
156 AliESDtrack *esdt = esdEvent->GetTrack(i);
157 // check tracks to skip
158 Bool_t skipThis = kFALSE;
159 for(Int_t j=0; j<fNTrksToSkip; j++) {
160 if(esdt->GetID()==fTrksToSkip[j]) {
161 if(fDebug) printf("skipping track: %d\n",i);
165 if(skipThis) continue;
167 // check number of clusters in ITS or TPC
168 if(esdt->GetNcls(fMode) < fMinClusters) continue;
170 if(fMode==0) { // ITS mode
171 if(fITSrefit && !(esdt->GetStatus()&AliESDtrack::kITSrefit)) continue;
172 Double_t x,p[5],cov[15];
173 esdt->GetExternalParameters(x,p);
174 esdt->GetExternalCovariance(cov);
175 t = new AliExternalTrackParam(x,esdt->GetAlpha(),p,cov);
176 } else if(fMode==1) { // TPC mode
177 t = (AliExternalTrackParam*)esdt->GetTPCInnerParam();
179 Double_t radius = 2.8; //something less than the beam pipe radius
180 if(!PropagateTrackTo(t,radius)) continue;
182 trkArrayOrig.AddLast(t);
183 idOrig[nTrksOrig]=(UShort_t)esdt->GetID();
185 } // end loop on ESD tracks
187 // call method that will reconstruct the vertex
188 FindPrimaryVertex(&trkArrayOrig,idOrig);
190 if(fMode==0) trkArrayOrig.Delete();
191 delete [] idOrig; idOrig=NULL;
194 f->Close(); delete f; f = NULL;
195 gSystem->Unlink("VertexerTracks.root");
199 return fCurrentVertex;
201 //----------------------------------------------------------------------------
202 AliESDVertex* AliVertexerTracks::FindPrimaryVertex(TObjArray *trkArrayOrig,
206 // Primary vertex using the AliExternalTrackParam's in the TObjArray.
207 // idOrig must contain the track IDs from AliESDtrack::GetID()
209 // 1st with 5*fNSigma*sigma cut w.r.t. to initial vertex
210 // + cut on sqrt(d0d0+z0z0) if fConstraint=kFALSE
211 // 2nd with fNSigma*sigma cut w.r.t. to vertex found in 1st iteration)
215 // accept 1-track case only if constraint is available
216 if(!fConstraint && fMinTracks==1) fMinTracks=2;
218 // read tracks from array
219 Int_t nTrksOrig = (Int_t)trkArrayOrig->GetEntriesFast();
220 if(fDebug) printf("Initial number of tracks: %d\n",nTrksOrig);
221 if(nTrksOrig<fMinTracks) {
222 if(fDebug) printf("TooFewTracks\n");
224 return fCurrentVertex;
227 // If fConstraint=kFALSE
228 // run VertexFinder(1) to get rough estimate of initVertex (x,y)
230 // fill fTrkArraySel, for VertexFinder()
231 fIdSel = new UShort_t[nTrksOrig];
232 PrepareTracks(*trkArrayOrig,idOrig,0);
233 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
234 Double_t cutsave = fDCAcut;
235 fDCAcut = fDCAcutIter0;
236 VertexFinder(1); // using weights, cutting dca < fDCAcutIter0
238 if(fVert.GetNContributors()>0) {
239 fVert.GetXYZ(fNominalPos);
240 fNominalPos[0] = fVert.GetXv();
241 fNominalPos[1] = fVert.GetYv();
242 fNominalPos[2] = fVert.GetZv();
243 if(fDebug) printf("No mean vertex: VertexFinder gives (%f, %f, %f)\n",fNominalPos[0],fNominalPos[1],fNominalPos[2]);
248 if(fDebug) printf("No mean vertex and VertexFinder failed\n");
255 // propagate tracks to fNominalPos vertex
257 // if(constraint) reject for |d0|>5*fNSigma*sigma w.r.t. fNominal... vertex
258 // else reject for |d0|\oplus|z0| > 5 mm w.r.t. fNominal... vertex
260 // propagate tracks to best between initVertex and fCurrentVertex
261 // preselect tracks (reject for |d0|>fNSigma*sigma w.r.t. best
262 // between initVertex and fCurrentVertex)
263 for(Int_t iter=1; iter<=2; iter++) {
264 if(fOnlyFitter && iter==1) continue;
265 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
266 fIdSel = new UShort_t[nTrksOrig];
267 Int_t nTrksSel = PrepareTracks(*trkArrayOrig,idOrig,iter);
268 if(fDebug) printf("N tracks selected in iteration %d: %d\n",iter,nTrksSel);
269 if(nTrksSel < fMinTracks) {
271 return fCurrentVertex;
277 if(fDebug) printf("Just one track\n");
278 OneTrackVertFinder();
281 case 1: StrLinVertexFinderMinDist(1); break;
282 case 2: StrLinVertexFinderMinDist(0); break;
283 case 3: HelixVertexFinder(); break;
284 case 4: VertexFinder(1); break;
285 case 5: VertexFinder(0); break;
286 default: printf("Wrong algorithm\n"); break;
289 if(fDebug) printf(" Vertex finding completed\n");
294 } // end loop on the two iterations
297 // set indices of used tracks
298 UShort_t *indices = 0;
299 if(fCurrentVertex->GetNContributors()>0) {
300 Int_t nIndices = (Int_t)fTrkArraySel.GetEntriesFast();
301 indices = new UShort_t[nIndices];
302 for(Int_t jj=0; jj<nIndices; jj++)
303 indices[jj] = fIdSel[jj];
304 fCurrentVertex->SetIndices(nIndices,indices);
306 delete [] indices; indices=NULL;
310 TString title="VertexerTracksNoConstraint";
312 title="VertexerTracksWithConstraint";
313 if(fOnlyFitter) title.Append("OnlyFitter");
315 fCurrentVertex->SetTitle(title.Data());
319 fCurrentVertex->PrintStatus();
320 fCurrentVertex->PrintIndices();
324 delete [] fIdSel; fIdSel=NULL;
325 fTrkArraySel.Delete();
326 if(fTrksToSkip) { delete [] fTrksToSkip; fTrksToSkip=NULL; }
329 return fCurrentVertex;
331 //------------------------------------------------------------------------
332 Double_t AliVertexerTracks::GetDeterminant3X3(Double_t matr[][3])
335 Double_t det=matr[0][0]*matr[1][1]*matr[2][2]-matr[0][0]*matr[1][2]*matr[2][1]-matr[0][1]*matr[1][0]*matr[2][2]+matr[0][1]*matr[1][2]*matr[2][0]+matr[0][2]*matr[1][0]*matr[2][1]-matr[0][2]*matr[1][1]*matr[2][0];
338 //-------------------------------------------------------------------------
339 void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t (*m)[3],Double_t *d)
342 Double_t x12=p0[0]-p1[0];
343 Double_t y12=p0[1]-p1[1];
344 Double_t z12=p0[2]-p1[2];
345 Double_t kk=x12*x12+y12*y12+z12*z12;
346 m[0][0]=2-2/kk*x12*x12;
347 m[0][1]=-2/kk*x12*y12;
348 m[0][2]=-2/kk*x12*z12;
349 m[1][0]=-2/kk*x12*y12;
350 m[1][1]=2-2/kk*y12*y12;
351 m[1][2]=-2/kk*y12*z12;
352 m[2][0]=-2/kk*x12*z12;
354 m[2][2]=2-2/kk*z12*z12;
355 d[0]=2*p0[0]-2/kk*p0[0]*x12*x12-2/kk*p0[2]*x12*z12-2/kk*p0[1]*x12*y12;
356 d[1]=2*p0[1]-2/kk*p0[1]*y12*y12-2/kk*p0[0]*x12*y12-2/kk*p0[2]*z12*y12;
357 d[2]=2*p0[2]-2/kk*p0[2]*z12*z12-2/kk*p0[0]*x12*z12-2/kk*p0[1]*z12*y12;
360 //--------------------------------------------------------------------------
361 void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t *sigmasq,Double_t (*m)[3],Double_t *d)
364 Double_t x12=p1[0]-p0[0];
365 Double_t y12=p1[1]-p0[1];
366 Double_t z12=p1[2]-p0[2];
368 Double_t den= x12*x12*sigmasq[1]*sigmasq[2]+y12*y12*sigmasq[0]*sigmasq[2]+z12*z12*sigmasq[0]*sigmasq[1];
370 Double_t kk= 2*(x12*x12/sigmasq[0]+y12*y12/sigmasq[1]+z12*z12/sigmasq[2]);
373 cc[0]=-x12/sigmasq[0];
374 cc[1]=-y12/sigmasq[1];
375 cc[2]=-z12/sigmasq[2];
377 Double_t ww=(-p0[0]*x12*sigmasq[1]*sigmasq[2]-p0[1]*y12*sigmasq[0]*sigmasq[2]-p0[2]*z12*sigmasq[0]*sigmasq[1])/den;
379 Double_t ss= -p0[0]*cc[0]-p0[1]*cc[1]-p0[2]*cc[2];
382 aa[0]=x12*sigmasq[1]*sigmasq[2]/den;
383 aa[1]=y12*sigmasq[0]*sigmasq[2]/den;
384 aa[2]=z12*sigmasq[0]*sigmasq[1]/den;
386 m[0][0]=aa[0]*(aa[0]*kk+2*cc[0])+2*cc[0]*aa[0]+2/sigmasq[0];
387 m[0][1]=aa[1]*(aa[0]*kk+2*cc[0])+2*cc[1]*aa[0];
388 m[0][2]=aa[2]*(aa[0]*kk+2*cc[0])+2*cc[2]*aa[0];
390 m[1][0]=aa[0]*(aa[1]*kk+2*cc[1])+2*cc[0]*aa[1];
391 m[1][1]=aa[1]*(aa[1]*kk+2*cc[1])+2*cc[1]*aa[1]+2/sigmasq[1];
392 m[1][2]=aa[2]*(aa[1]*kk+2*cc[1])+2*cc[2]*aa[1];
394 m[2][0]=aa[0]*(aa[2]*kk+2*cc[2])+2*cc[0]*aa[2];
395 m[2][1]=aa[1]*(aa[2]*kk+2*cc[2])+2*cc[1]*aa[2];
396 m[2][2]=aa[2]*(aa[2]*kk+2*cc[2])+2*cc[2]*aa[2]+2/sigmasq[2];
398 d[0]=-ww*(aa[0]*kk+2*cc[0])-2*ss*aa[0]+2*p0[0]/sigmasq[0];
399 d[1]=-ww*(aa[1]*kk+2*cc[1])-2*ss*aa[1]+2*p0[1]/sigmasq[1];
400 d[2]=-ww*(aa[2]*kk+2*cc[2])-2*ss*aa[2]+2*p0[2]/sigmasq[2];
403 //--------------------------------------------------------------------------
404 Double_t AliVertexerTracks::GetStrLinMinDist(Double_t *p0,Double_t *p1,Double_t *x0)
407 Double_t x12=p0[0]-p1[0];
408 Double_t y12=p0[1]-p1[1];
409 Double_t z12=p0[2]-p1[2];
410 Double_t x10=p0[0]-x0[0];
411 Double_t y10=p0[1]-x0[1];
412 Double_t z10=p0[2]-x0[2];
413 // return ((x10*x10+y10*y10+z10*z10)*(x12*x12+y12*y12+z12*z12)-(x10*x12+y10*y12+z10*z12)*(x10*x12+y10*y12+z10*z12))/(x12*x12+y12*y12+z12*z12);
414 return ((y10*z12-z10*y12)*(y10*z12-z10*y12)+
415 (z10*x12-x10*z12)*(z10*x12-x10*z12)+
416 (x10*y12-y10*x12)*(x10*y12-y10*x12))
417 /(x12*x12+y12*y12+z12*z12);
419 //---------------------------------------------------------------------------
420 void AliVertexerTracks::OneTrackVertFinder()
422 // find vertex for events with 1 track, using DCA to nominal beam axis
423 if(fDebug) printf("Number of prepared tracks =%d - Call OneTrackVertFinder",fTrkArraySel.GetEntries());
424 AliExternalTrackParam *track1;
425 track1 = (AliExternalTrackParam*)fTrkArraySel.At(0);
426 Double_t alpha=track1->GetAlpha();
427 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
428 Double_t pos[3],dir[3];
429 track1->GetXYZAt(mindist,GetFieldkG(),pos);
430 track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
431 AliStrLine *line1 = new AliStrLine(pos,dir);
432 Double_t p1[3]={fNominalPos[0],fNominalPos[1],0.};
433 Double_t p2[3]={fNominalPos[0],fNominalPos[1],10.};
434 AliStrLine *zeta=new AliStrLine(p1,p2,kTRUE);
435 Double_t crosspoint[3]={0.,0.,0.};
438 Int_t retcode = zeta->Cross(line1,crosspoint);
440 sigma=line1->GetDistFromPoint(crosspoint);
445 fVert.SetXYZ(crosspoint);
446 fVert.SetDispersion(sigma);
447 fVert.SetNContributors(nContrib);
449 //---------------------------------------------------------------------------
450 void AliVertexerTracks::HelixVertexFinder()
452 // Get estimate of vertex position in (x,y) from tracks DCA
457 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
459 Int_t nacc = (Int_t)fTrkArraySel.GetEntriesFast();
461 Double_t aver[3]={0.,0.,0.};
462 Double_t averquad[3]={0.,0.,0.};
463 Double_t sigmaquad[3]={0.,0.,0.};
466 AliExternalTrackParam *track1;
467 AliExternalTrackParam *track2;
470 Double_t alpha, cs, sn;
471 Double_t crosspoint[3];
472 for(Int_t i=0; i<nacc; i++){
473 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
476 for(Int_t j=i+1; j<nacc; j++){
477 track2 = (AliExternalTrackParam*)fTrkArraySel.At(j);
479 distCA=track2->PropagateToDCA(track1,GetFieldkG());
480 if(fDCAcut<=0 ||(fDCAcut>0&&distCA<fDCAcut)){
482 alpha=track1->GetAlpha();
483 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
484 Double_t x1=x*cs - track1->GetY()*sn;
485 Double_t y1=x*sn + track1->GetY()*cs;
486 Double_t z1=track1->GetZ();
488 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
490 alpha=track2->GetAlpha();
491 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
492 Double_t x2=x*cs - track2->GetY()*sn;
493 Double_t y2=x*sn + track2->GetY()*cs;
494 Double_t z2=track2->GetZ();
495 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
496 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
497 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
498 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
499 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
500 crosspoint[0]=wx1*x1 + wx2*x2;
501 crosspoint[1]=wy1*y1 + wy2*y2;
502 crosspoint[2]=wz1*z1 + wz2*z2;
505 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
506 for(Int_t jj=0;jj<3;jj++)averquad[jj]+=(crosspoint[jj]*crosspoint[jj]);
512 for(Int_t jj=0;jj<3;jj++){
513 initPos[jj] = aver[jj]/ncombi;
514 averquad[jj]/=ncombi;
515 sigmaquad[jj]=averquad[jj]-initPos[jj]*initPos[jj];
516 sigma+=sigmaquad[jj];
518 sigma=TMath::Sqrt(TMath::Abs(sigma));
521 Warning("HelixVertexFinder","Finder did not succed");
524 fVert.SetXYZ(initPos);
525 fVert.SetDispersion(sigma);
526 fVert.SetNContributors(ncombi);
528 //----------------------------------------------------------------------------
529 Int_t AliVertexerTracks::PrepareTracks(TObjArray &trkArrayOrig,
534 // Propagate tracks to initial vertex position and store them in a TObjArray
536 if(fDebug) printf(" PrepareTracks()\n");
538 Int_t nTrksOrig = (Int_t)trkArrayOrig.GetEntriesFast();
541 Double_t sigmaCurr[3];
542 Double_t normdistx,normdisty;
543 Double_t d0z0[2],covd0z0[3];
546 AliESDVertex *initVertex = new AliESDVertex(fNominalPos,fNominalCov,1,1);
548 if(!fTrkArraySel.IsEmpty()) fTrkArraySel.Delete();
550 AliExternalTrackParam *track=0;
553 for(Int_t i=0; i<nTrksOrig; i++) {
554 track = new AliExternalTrackParam(*(AliExternalTrackParam*)trkArrayOrig.At(i));
556 if(TMath::Abs(track->GetTgl())>fMaxTgl) {
557 if(fDebug) printf(" rejecting track with tgl = %f\n",track->GetTgl());
558 delete track; continue;
561 Bool_t propagateOK = kFALSE;
562 // propagate track to vertex
563 if(optImpParCut<2 || fOnlyFitter) { // optImpParCut==1 or 0
564 propagateOK = track->PropagateToDCA(initVertex,GetFieldkG(),100.,d0z0,covd0z0);
565 } else { // optImpParCut==2
566 fCurrentVertex->GetSigmaXYZ(sigmaCurr);
567 normdistx = TMath::Abs(fCurrentVertex->GetXv()-fNominalPos[0])/TMath::Sqrt(sigmaCurr[0]*sigmaCurr[0]+fNominalCov[0]);
568 normdisty = TMath::Abs(fCurrentVertex->GetYv()-fNominalPos[1])/TMath::Sqrt(sigmaCurr[1]*sigmaCurr[1]+fNominalCov[2]);
569 if(normdistx < 3. && normdisty < 3. &&
570 (sigmaCurr[0]+sigmaCurr[1])<(TMath::Sqrt(fNominalCov[0])+TMath::Sqrt(fNominalCov[2]))) {
571 propagateOK = track->PropagateToDCA(fCurrentVertex,GetFieldkG(),100.,d0z0,covd0z0);
573 propagateOK = track->PropagateToDCA(initVertex,GetFieldkG(),100.,d0z0,covd0z0);
578 if(fDebug) printf(" rejected\n");
579 delete track; continue;
582 sigmad0 = TMath::Sqrt(covd0z0[0]);
583 maxd0rphi = fNSigma*sigmad0;
584 if(optImpParCut==1) maxd0rphi *= 5.;
585 maxd0rphi = TMath::Min(maxd0rphi,fFiducialR);
586 //sigmad0z0 = TMath::Sqrt(covd0z0[0]+covd0z0[2]); // for future improvement
587 //maxd0z0 = 10.*fNSigma*sigmad0z0;
589 if(fDebug) printf("trk %d; id %d; |d0| = %f; d0 cut = %f; |z0| = %f; |d0|oplus|z0| = %f; d0z0 cut = %f\n",i,(Int_t)idOrig[i],TMath::Abs(d0z0[0]),maxd0rphi,TMath::Abs(d0z0[1]),TMath::Sqrt(d0z0[0]*d0z0[0]+d0z0[1]*d0z0[1]),fMaxd0z0);
592 //---- track selection based on impact parameters ----//
594 // always reject tracks outside fiducial volume
595 if(TMath::Abs(d0z0[0])>fFiducialR || TMath::Abs(d0z0[1])>fFiducialZ) {
596 if(fDebug) printf(" rejected\n");
597 delete track; continue;
600 // during iterations 1 and 2 , reject tracks with d0rphi > maxd0rphi
601 if(optImpParCut>0 && TMath::Abs(d0z0[0])>maxd0rphi) {
602 if(fDebug) printf(" rejected\n");
603 delete track; continue;
606 // if fConstraint=kFALSE, during iterations 1 and 2 ||
607 // if fConstraint=kTRUE, during iteration 2,
608 // select tracks with d0oplusz0 < fMaxd0z0
609 if((!fConstraint && optImpParCut>0 && fVert.GetNContributors()>0) ||
610 ( fConstraint && optImpParCut==2)) {
612 TMath::Sqrt(d0z0[0]*d0z0[0]+d0z0[1]*d0z0[1])>fMaxd0z0) {
613 if(fDebug) printf(" rejected\n");
614 delete track; continue;
618 // track passed all selections
619 fTrkArraySel.AddLast(track);
620 fIdSel[nTrksSel] = idOrig[i];
622 } // end loop on tracks
628 //----------------------------------------------------------------------------
629 Bool_t AliVertexerTracks::PropagateTrackTo(AliExternalTrackParam *track,
631 //----------------------------------------------------------------
632 // COPIED from AliTracker
634 // Propagates the track to the plane X=xk (cm).
636 // Origin: Marian Ivanov, Marian.Ivanov@cern.ch
637 //----------------------------------------------------------------
639 const Double_t kEpsilon = 0.00001;
640 Double_t xpos = track->GetX();
641 Double_t dir = (xpos<xToGo) ? 1. : -1.;
642 Double_t maxStep = 5;
643 Double_t maxSnp = 0.8;
645 while ( (xToGo-xpos)*dir > kEpsilon){
646 Double_t step = dir*TMath::Min(TMath::Abs(xToGo-xpos), maxStep);
647 Double_t x = xpos+step;
648 Double_t xyz0[3],xyz1[3];
649 track->GetXYZ(xyz0); //starting global position
651 if(!track->GetXYZAt(x,GetFieldkG(),xyz1)) return kFALSE; // no prolongation
652 xyz1[2]+=kEpsilon; // waiting for bug correction in geo
654 if(TMath::Abs(track->GetSnpAt(x,GetFieldkG())) >= maxSnp) return kFALSE;
655 if(!track->PropagateTo(x,GetFieldkG())) return kFALSE;
657 if(TMath::Abs(track->GetSnp()) >= maxSnp) return kFALSE;
658 track->GetXYZ(xyz0); // global position
659 Double_t alphan = TMath::ATan2(xyz0[1], xyz0[0]);
661 Double_t ca=TMath::Cos(alphan-track->GetAlpha()),
662 sa=TMath::Sin(alphan-track->GetAlpha());
663 Double_t sf=track->GetSnp(), cf=TMath::Sqrt(1.- sf*sf);
664 Double_t sinNew = sf*ca - cf*sa;
665 if(TMath::Abs(sinNew) >= maxSnp) return kFALSE;
666 if(!track->Rotate(alphan)) return kFALSE;
668 xpos = track->GetX();
672 //---------------------------------------------------------------------------
673 AliESDVertex* AliVertexerTracks::RemoveTracksFromVertex(AliESDVertex *inVtx,
679 // Removes tracks in trksTree from fit of inVtx
682 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraint")) {
683 printf("ERROR: primary vertex has no constraint: cannot remove tracks\n");
686 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraintOnlyFitter"))
687 printf("WARNING: result of tracks' removal will be only approximately correct\n");
690 rv(0,0) = inVtx->GetXv();
691 rv(1,0) = inVtx->GetYv();
692 rv(2,0) = inVtx->GetZv();
695 inVtx->GetCovMatrix(cov);
697 vV(0,1) = cov[1]; vV(1,0) = cov[1];
699 vV(0,2) = cov[3]; vV(2,0) = cov[3];
700 vV(1,2) = cov[4]; vV(2,1) = cov[4];
703 TMatrixD sumWi(TMatrixD::kInverted,vV);
704 TMatrixD sumWiri(sumWi,TMatrixD::kMult,rv);
706 Int_t nUsedTrks = inVtx->GetNIndices();
707 Double_t chi2 = inVtx->GetChi2();
709 AliExternalTrackParam *track = 0;
710 Int_t ntrks = (Int_t)trkArray->GetEntriesFast();
711 for(Int_t i=0;i<ntrks;i++) {
712 track = (AliExternalTrackParam*)trkArray->At(i);
713 if(!inVtx->UsesTrack(id[i])) {
714 printf("track %d was not used in vertex fit\n",id[i]);
717 Double_t alpha = track->GetAlpha();
718 Double_t xl = diamondxy[0]*TMath::Cos(alpha)+diamondxy[1]*TMath::Sin(alpha);
719 track->PropagateTo(xl,GetFieldkG());
720 // vector of track global coordinates
722 // covariance matrix of ri
725 // get space point from track
726 if(!TrackToPoint(track,ri,wWi)) continue;
728 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
734 TMatrixD deltar = rv; deltar -= ri;
735 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
736 Double_t chi2i = deltar(0,0)*wWideltar(0,0)+
737 deltar(1,0)*wWideltar(1,0)+
738 deltar(2,0)*wWideltar(2,0);
739 // remove from total chi2
744 printf("Trying to remove too many tracks!\n");
752 // new inverted of weights matrix
753 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
755 // new position of primary vertex
756 rvnew.Mult(vVnew,sumWiri);
758 Double_t position[3];
759 position[0] = rvnew(0,0);
760 position[1] = rvnew(1,0);
761 position[2] = rvnew(2,0);
769 // store data in the vertex object
770 AliESDVertex *outVtx = new AliESDVertex(position,cov,chi2,nUsedTrks);
771 outVtx->SetTitle(inVtx->GetTitle());
772 UShort_t *inindices = inVtx->GetIndices();
773 Int_t nIndices = nUsedTrks;
774 UShort_t *outindices = new UShort_t[nIndices];
776 for(Int_t k=0; k<inVtx->GetNIndices(); k++) {
777 Bool_t copyindex=kTRUE;
778 for(Int_t l=0; l<ntrks; l++) {
779 if(inindices[k]==id[l]) copyindex=kFALSE;
782 outindices[j] = inindices[k]; j++;
785 outVtx->SetIndices(nIndices,outindices);
786 delete [] outindices;
789 printf("Vertex before removing tracks:\n");
790 inVtx->PrintStatus();
791 inVtx->PrintIndices();
792 printf("Vertex after removing tracks:\n");
793 outVtx->PrintStatus();
794 outVtx->PrintIndices();
799 //---------------------------------------------------------------------------
800 void AliVertexerTracks::SetCuts(Double_t *cuts)
806 SetDCAcutIter0(cuts[1]);
808 SetMinClusters((Int_t)(cuts[3]));
809 SetMinTracks((Int_t)(cuts[4]));
810 SetNSigmad0(cuts[5]);
811 SetMinDetFitter(cuts[6]);
813 SetFiducialRZ(cuts[8],cuts[9]);
817 //---------------------------------------------------------------------------
818 void AliVertexerTracks::SetITSMode(Double_t dcacut,
819 Double_t dcacutIter0,
824 Double_t mindetfitter,
830 // Cut values for ITS mode
833 SetITSrefitRequired();
835 SetDCAcutIter0(dcacutIter0);
837 SetMinClusters(minCls);
838 SetMinTracks(mintrks);
840 SetMinDetFitter(mindetfitter);
842 SetFiducialRZ(fidR,fidZ);
846 //---------------------------------------------------------------------------
847 void AliVertexerTracks::SetTPCMode(Double_t dcacut,
848 Double_t dcacutIter0,
853 Double_t mindetfitter,
859 // Cut values for TPC mode
862 SetITSrefitNotRequired();
864 SetDCAcutIter0(dcacutIter0);
866 SetMinClusters(minCls);
867 SetMinTracks(mintrks);
869 SetMinDetFitter(mindetfitter);
871 SetFiducialRZ(fidR,fidZ);
875 //---------------------------------------------------------------------------
876 void AliVertexerTracks::SetSkipTracks(Int_t n,Int_t *skipped)
879 // Mark the tracks not to be used in the vertex reconstruction.
880 // Tracks are identified by AliESDtrack::GetID()
882 fNTrksToSkip = n; fTrksToSkip = new Int_t[n];
883 for(Int_t i=0;i<n;i++) fTrksToSkip[i] = skipped[i];
886 //---------------------------------------------------------------------------
887 void AliVertexerTracks::SetVtxStart(AliESDVertex *vtx)
890 // Set initial vertex knowledge
892 vtx->GetXYZ(fNominalPos);
893 vtx->GetCovMatrix(fNominalCov);
897 //---------------------------------------------------------------------------
898 void AliVertexerTracks::StrLinVertexFinderMinDist(Int_t optUseWeights)
900 AliExternalTrackParam *track1;
901 const Int_t knacc = (Int_t)fTrkArraySel.GetEntriesFast();
902 static TClonesArray linarray("AliStrLine",knacc);
903 for(Int_t i=0; i<knacc; i++){
904 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
905 Double_t alpha=track1->GetAlpha();
906 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
907 Double_t pos[3],dir[3],sigmasq[3];
908 track1->GetXYZAt(mindist,GetFieldkG(),pos);
909 track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
910 sigmasq[0]=TMath::Sin(alpha)*TMath::Sin(alpha)*track1->GetSigmaY2();
911 sigmasq[1]=TMath::Cos(alpha)*TMath::Cos(alpha)*track1->GetSigmaY2();
912 sigmasq[2]=track1->GetSigmaZ2();
915 if(!TrackToPoint(track1,ri,wWi)) continue;
918 for(Int_t ia=0;ia<3;ia++){
919 for(Int_t ib=0;ib<3;ib++){
920 wmat[iel]=wWi(ia,ib);
924 new(linarray[i]) AliStrLine(pos,sigmasq,wmat,dir);
926 fVert=TrackletVertexFinder(&linarray,optUseWeights);
929 //---------------------------------------------------------------------------
930 AliESDVertex AliVertexerTracks::TrackletVertexFinder(TClonesArray *lines, Int_t optUseWeights)
932 // Calculate the point at minimum distance to prepared tracks
934 const Int_t knacc = (Int_t)lines->GetEntriesFast();
935 Double_t initPos[3]={0.,0.,0.};
937 Double_t (*vectP0)[3]=new Double_t [knacc][3];
938 Double_t (*vectP1)[3]=new Double_t [knacc][3];
941 Double_t dsum[3]={0,0,0};
943 for(Int_t i=0;i<3;i++){
944 for(Int_t j=0;j<3;j++){
950 for(Int_t i=0; i<knacc; i++){
951 AliStrLine* line1 = (AliStrLine*)lines->At(i);
952 Double_t p0[3],cd[3],sigmasq[3];
956 line1->GetSigma2P0(sigmasq);
957 line1->GetWMatrix(wmat);
960 for(Int_t ia=0;ia<3;ia++){
961 for(Int_t ib=0;ib<3;ib++){
962 wWi(ia,ib)=wmat[iel];
969 Double_t p1[3]={p0[0]+cd[0],p0[1]+cd[1],p0[2]+cd[2]};
979 if(optUseWeights==0)GetStrLinDerivMatrix(p0,p1,matr,dknow);
980 else GetStrLinDerivMatrix(p0,p1,sigmasq,matr,dknow);
983 for(Int_t iii=0;iii<3;iii++){
984 dsum[iii]+=dknow[iii];
985 for(Int_t lj=0;lj<3;lj++) sum[iii][lj]+=matr[iii][lj];
989 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
990 Double_t covmatrix[6];
991 covmatrix[0] = invsumWi(0,0);
992 covmatrix[1] = invsumWi(0,1);
993 covmatrix[2] = invsumWi(1,1);
994 covmatrix[3] = invsumWi(0,2);
995 covmatrix[4] = invsumWi(1,2);
996 covmatrix[5] = invsumWi(2,2);
999 Double_t det=GetDeterminant3X3(sum);
1003 for(Int_t zz=0;zz<3;zz++){
1004 for(Int_t ww=0;ww<3;ww++){
1005 for(Int_t kk=0;kk<3;kk++) vett[ww][kk]=sum[ww][kk];
1007 for(Int_t kk=0;kk<3;kk++) vett[kk][zz]=dsum[kk];
1008 initPos[zz]=GetDeterminant3X3(vett)/det;
1012 for(Int_t i=0; i<knacc; i++){
1013 Double_t p0[3]={0,0,0},p1[3]={0,0,0};
1014 for(Int_t ii=0;ii<3;ii++){
1015 p0[ii]=vectP0[i][ii];
1016 p1[ii]=vectP1[i][ii];
1018 sigma+=GetStrLinMinDist(p0,p1,initPos);
1021 if(sigma>0.) {sigma=TMath::Sqrt(sigma);}else{sigma=999;}
1025 AliESDVertex theVert(initPos,covmatrix,99999.,knacc);
1026 theVert.SetDispersion(sigma);
1031 //---------------------------------------------------------------------------
1032 Bool_t AliVertexerTracks::TrackToPoint(AliExternalTrackParam *t,
1033 TMatrixD &ri,TMatrixD &wWi,
1034 Bool_t uUi3by3) const
1037 // Extract from the AliExternalTrackParam the global coordinates ri and covariance matrix
1038 // wWi of the space point that it represents (to be used in VertexFitter())
1042 Double_t rotAngle = t->GetAlpha();
1043 if(rotAngle<0.) rotAngle += 2.*TMath::Pi();
1044 Double_t cosRot = TMath::Cos(rotAngle);
1045 Double_t sinRot = TMath::Sin(rotAngle);
1047 ri(0,0) = t->GetX()*cosRot-t->GetY()*sinRot;
1048 ri(1,0) = t->GetX()*sinRot+t->GetY()*cosRot;
1049 ri(2,0) = t->GetZ();
1054 // matrix to go from global (x,y,z) to local (y,z);
1063 // covariance matrix of local (y,z) - inverted
1065 uUi(0,0) = t->GetSigmaY2();
1066 uUi(0,1) = t->GetSigmaZY();
1067 uUi(1,0) = t->GetSigmaZY();
1068 uUi(1,1) = t->GetSigmaZ2();
1069 //printf(" Ui :\n");
1070 //printf(" %f %f\n",uUi(0,0),uUi(0,1));
1071 //printf(" %f %f\n",uUi(1,0),uUi(1,1));
1073 if(uUi.Determinant() <= 0.) return kFALSE;
1074 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
1076 // weights matrix: wWi = qQiT * uUiInv * qQi
1077 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
1078 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
1081 if(fVert.GetNContributors()<1) AliFatal("Vertex from finder is empty");
1082 // matrix to go from global (x,y,z) to local (x,y,z);
1094 // covariance of fVert along the track
1095 Double_t p[3],pt,ptot;
1097 pt = TMath::Sqrt(p[0]*p[0]+p[1]*p[1]);
1098 ptot = TMath::Sqrt(pt*pt+p[2]*p[2]);
1099 Double_t cphi = p[0]/pt; //cos(phi)=px/pt
1100 Double_t sphi = p[1]/pt; //sin(phi)=py/pt
1101 Double_t clambda = pt/ptot; //cos(lambda)=pt/ptot
1102 Double_t slambda = p[2]/ptot; //sin(lambda)=pz/ptot
1103 Double_t covfVert[6];
1104 fVert.GetCovMatrix(covfVert);
1105 Double_t covfVertalongt =
1106 covfVert[0]*cphi*cphi*clambda*clambda
1107 +covfVert[1]*2.*cphi*sphi*clambda*clambda
1108 +covfVert[3]*2.*cphi*clambda*slambda
1109 +covfVert[2]*sphi*sphi*clambda*clambda
1110 +covfVert[4]*2.*sphi*clambda*slambda
1111 +covfVert[5]*slambda*slambda;
1112 // covariance matrix of local (x,y,z) - inverted
1114 uUi(0,0) = covfVertalongt * fnSigmaForUi00 * fnSigmaForUi00;
1115 if(fDebug) printf("=====> sqrtUi00 cm %f\n",TMath::Sqrt(uUi(0,0)));
1119 uUi(1,1) = t->GetSigmaY2();
1120 uUi(1,2) = t->GetSigmaZY();
1122 uUi(2,1) = t->GetSigmaZY();
1123 uUi(2,2) = t->GetSigmaZ2();
1124 //printf(" Ui :\n");
1125 //printf(" %f %f\n",uUi(0,0),uUi(0,1));
1126 //printf(" %f %f\n",uUi(1,0),uUi(1,1));
1128 if(uUi.Determinant() <= 0.) return kFALSE;
1129 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
1131 // weights matrix: wWi = qQiT * uUiInv * qQi
1132 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
1133 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
1140 //---------------------------------------------------------------------------
1141 void AliVertexerTracks::TooFewTracks()
1144 // When the number of tracks is < fMinTracks,
1145 // deal with vertices not found and prepare to exit
1147 if(fDebug) printf("TooFewTracks\n");
1149 Double_t pos[3],err[3];
1150 pos[0] = fNominalPos[0];
1151 err[0] = TMath::Sqrt(fNominalCov[0]);
1152 pos[1] = fNominalPos[1];
1153 err[1] = TMath::Sqrt(fNominalCov[2]);
1154 pos[2] = fNominalPos[2];
1155 err[2] = TMath::Sqrt(fNominalCov[5]);
1156 Int_t ncontr = (err[0]>1. ? -1 : -3);
1158 fCurrentVertex = new AliESDVertex(pos,err);
1159 fCurrentVertex->SetNContributors(ncontr);
1162 fCurrentVertex->SetTitle("VertexerTracksWithConstraint");
1164 fCurrentVertex->SetTitle("VertexerTracksNoConstraint");
1167 if(!fTrkArraySel.IsEmpty()) fTrkArraySel.Delete();
1168 if(fIdSel) {delete [] fIdSel; fIdSel=NULL;}
1169 if(fTrksToSkip) {delete [] fTrksToSkip; fTrksToSkip=NULL;}
1173 //---------------------------------------------------------------------------
1174 void AliVertexerTracks::VertexFinder(Int_t optUseWeights)
1177 // Get estimate of vertex position in (x,y) from tracks DCA
1179 Double_t initPos[3];
1181 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
1182 Int_t nacc = (Int_t)fTrkArraySel.GetEntriesFast();
1183 Double_t aver[3]={0.,0.,0.};
1184 Double_t aversq[3]={0.,0.,0.};
1185 Double_t sigmasq[3]={0.,0.,0.};
1188 AliExternalTrackParam *track1;
1189 AliExternalTrackParam *track2;
1190 Double_t pos[3],dir[3];
1191 Double_t alpha,mindist;
1193 for(Int_t i=0; i<nacc; i++){
1194 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
1195 alpha=track1->GetAlpha();
1196 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1197 track1->GetXYZAt(mindist,GetFieldkG(),pos);
1198 track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
1199 AliStrLine *line1 = new AliStrLine(pos,dir);
1201 // AliStrLine *line1 = new AliStrLine();
1202 // track1->ApproximateHelixWithLine(mindist,GetFieldkG(),line1);
1204 for(Int_t j=i+1; j<nacc; j++){
1205 track2 = (AliExternalTrackParam*)fTrkArraySel.At(j);
1206 alpha=track2->GetAlpha();
1207 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1208 track2->GetXYZAt(mindist,GetFieldkG(),pos);
1209 track2->GetPxPyPzAt(mindist,GetFieldkG(),dir);
1210 AliStrLine *line2 = new AliStrLine(pos,dir);
1211 // AliStrLine *line2 = new AliStrLine();
1212 // track2->ApproximateHelixWithLine(mindist,GetFieldkG(),line2);
1213 Double_t distCA=line2->GetDCA(line1);
1214 //printf("%d %d %f\n",i,j,distCA);
1215 if(fDCAcut<=0 || (fDCAcut>0&&distCA<fDCAcut)){
1216 Double_t pnt1[3],pnt2[3],crosspoint[3];
1218 if(optUseWeights<=0){
1219 Int_t retcode = line2->Cross(line1,crosspoint);
1222 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
1223 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1226 if(optUseWeights>0){
1227 Int_t retcode = line1->CrossPoints(line2,pnt1,pnt2);
1230 alpha=track1->GetAlpha();
1231 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
1232 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
1233 alpha=track2->GetAlpha();
1234 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
1235 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
1236 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
1237 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
1238 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
1239 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
1240 crosspoint[0]=wx1*pnt1[0] + wx2*pnt2[0];
1241 crosspoint[1]=wy1*pnt1[1] + wy2*pnt2[1];
1242 crosspoint[2]=wz1*pnt1[2] + wz2*pnt2[2];
1245 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
1246 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1255 for(Int_t jj=0;jj<3;jj++){
1256 initPos[jj] = aver[jj]/ncombi;
1257 //printf("%f\n",initPos[jj]);
1259 sigmasq[jj]=aversq[jj]-initPos[jj]*initPos[jj];
1262 sigma=TMath::Sqrt(TMath::Abs(sigma));
1265 Warning("VertexFinder","Finder did not succed");
1268 fVert.SetXYZ(initPos);
1269 fVert.SetDispersion(sigma);
1270 fVert.SetNContributors(ncombi);
1272 //---------------------------------------------------------------------------
1273 void AliVertexerTracks::VertexFitter()
1276 // The optimal estimate of the vertex position is given by a "weighted
1277 // average of tracks positions".
1278 // Original method: V. Karimaki, CMS Note 97/0051
1280 Bool_t useConstraint = fConstraint;
1281 Double_t initPos[3];
1283 fVert.GetXYZ(initPos);
1285 initPos[0]=fNominalPos[0];
1286 initPos[1]=fNominalPos[1];
1287 initPos[2]=fNominalPos[2];
1290 Int_t nTrksSel = (Int_t)fTrkArraySel.GetEntries();
1291 if(nTrksSel==1) useConstraint=kTRUE;
1293 printf("--- VertexFitter(): start\n");
1294 printf(" Number of tracks in array: %d\n",nTrksSel);
1295 printf(" Minimum # tracks required in fit: %d\n",fMinTracks);
1296 printf(" Vertex position after finder: %f,%f,%f\n",initPos[0],initPos[1],initPos[2]);
1297 if(useConstraint) printf(" This vertex will be used in fit: (%f+-%f,%f+-%f)\n",fNominalPos[0],TMath::Sqrt(fNominalCov[0]),fNominalPos[1],TMath::Sqrt(fNominalCov[2]));
1300 // special treatment for few-tracks fits (e.g. secondary vertices)
1301 Bool_t uUi3by3 = kFALSE; if(nTrksSel<5 && !useConstraint) uUi3by3 = kTRUE;
1306 rv(0,0) = initPos[0];
1307 rv(1,0) = initPos[1];
1309 Double_t xlStart,alpha;
1311 Double_t chi2,chi2i,chi2b;
1312 AliExternalTrackParam *t = 0;
1315 // initial vertex covariance matrix
1317 vVb(0,0) = fNominalCov[0];
1318 vVb(0,1) = fNominalCov[1];
1320 vVb(1,0) = fNominalCov[1];
1321 vVb(1,1) = fNominalCov[2];
1325 vVb(2,2) = fNominalCov[5];
1326 TMatrixD vVbInv(TMatrixD::kInverted,vVb);
1328 rb(0,0) = fNominalPos[0];
1329 rb(1,0) = fNominalPos[1];
1330 rb(2,0) = fNominalPos[2];
1331 TMatrixD vVbInvrb(vVbInv,TMatrixD::kMult,rb);
1335 // 1st - estimate of vtx using all tracks
1336 // 2nd - estimate of global chi2
1337 for(step=0; step<2; step++) {
1338 if(fDebug) printf(" step = %d\n",step);
1342 if(step==1) { initPos[0]=rv(0,0); initPos[0]=rv(1,0); }
1344 TMatrixD sumWiri(3,1);
1345 TMatrixD sumWi(3,3);
1346 for(i=0; i<3; i++) {
1348 for(j=0; j<3; j++) sumWi(j,i) = 0.;
1351 // mean vertex constraint
1354 sumWiri(i,0) += vVbInvrb(i,0);
1355 for(k=0;k<3;k++) sumWi(i,k) += vVbInv(i,k);
1358 TMatrixD deltar = rv; deltar -= rb;
1359 TMatrixD vVbInvdeltar(vVbInv,TMatrixD::kMult,deltar);
1360 chi2b = deltar(0,0)*vVbInvdeltar(0,0)+
1361 deltar(1,0)*vVbInvdeltar(1,0)+
1362 deltar(2,0)*vVbInvdeltar(2,0);
1367 for(k=0; k<nTrksSel; k++) {
1368 // get track from track array
1369 t = (AliExternalTrackParam*)fTrkArraySel.At(k);
1370 alpha = t->GetAlpha();
1371 xlStart = initPos[0]*TMath::Cos(alpha)+initPos[1]*TMath::Sin(alpha);
1372 // to vtxSeed (from finder)
1373 t->PropagateTo(xlStart,GetFieldkG());
1375 // vector of track global coordinates
1377 // covariance matrix of ri
1380 // get space point from track
1381 if(!TrackToPoint(t,ri,wWi,uUi3by3)) continue;
1382 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
1385 TMatrixD deltar = rv; deltar -= ri;
1386 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
1387 chi2i = deltar(0,0)*wWideltar(0,0)+
1388 deltar(1,0)*wWideltar(1,0)+
1389 deltar(2,0)*wWideltar(2,0);
1391 // add to total chi2
1398 } // end loop on tracks
1400 if(nTrksUsed < fMinTracks) {
1405 Double_t determinant = sumWi.Determinant();
1406 if(determinant < fMinDetFitter) {
1407 printf("det(V) = %f (<%f)\n",determinant,fMinDetFitter);
1413 // inverted of weights matrix
1414 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
1416 // position of primary vertex
1417 rv.Mult(vV,sumWiri);
1419 } // end loop on the 2 steps
1426 Double_t position[3];
1427 position[0] = rv(0,0);
1428 position[1] = rv(1,0);
1429 position[2] = rv(2,0);
1430 Double_t covmatrix[6];
1431 covmatrix[0] = vV(0,0);
1432 covmatrix[1] = vV(0,1);
1433 covmatrix[2] = vV(1,1);
1434 covmatrix[3] = vV(0,2);
1435 covmatrix[4] = vV(1,2);
1436 covmatrix[5] = vV(2,2);
1438 // for correct chi2/ndf, count constraint as additional "track"
1439 if(fConstraint) nTrksUsed++;
1440 // store data in the vertex object
1441 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nTrksUsed);
1444 printf(" Vertex after fit:\n");
1445 fCurrentVertex->PrintStatus();
1446 printf("--- VertexFitter(): finish\n");
1451 //----------------------------------------------------------------------------
1452 AliESDVertex* AliVertexerTracks::VertexForSelectedTracks(TObjArray *trkArray,
1454 Bool_t optUseFitter,
1455 Bool_t optPropagate)
1458 // Return vertex from tracks (AliExternalTrackParam) in array
1463 // get tracks and propagate them to initial vertex position
1464 fIdSel = new UShort_t[(Int_t)trkArray->GetEntriesFast()];
1465 Int_t nTrksSel = PrepareTracks(*trkArray,id,0);
1466 if(nTrksSel < TMath::Max(2,fMinTracks)) {
1468 return fCurrentVertex;
1473 case 1: StrLinVertexFinderMinDist(1); break;
1474 case 2: StrLinVertexFinderMinDist(0); break;
1475 case 3: HelixVertexFinder(); break;
1476 case 4: VertexFinder(1); break;
1477 case 5: VertexFinder(0); break;
1478 default: printf("Wrong algorithm\n"); break;
1480 if(fDebug) printf(" Vertex finding completed\n");
1486 Double_t position[3]={fVert.GetXv(),fVert.GetYv(),fVert.GetZv()};
1487 Double_t covmatrix[6];
1488 fVert.GetCovMatrix(covmatrix);
1489 Double_t chi2=99999.;
1490 Int_t nTrksUsed=fVert.GetNContributors();
1491 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nTrksUsed);
1493 fCurrentVertex->SetDispersion(fVert.GetDispersion());
1496 // set indices of used tracks and propagate track to found vertex
1497 UShort_t *indices = 0;
1498 Double_t d0z0[2],covd0z0[3];
1499 AliExternalTrackParam *t = 0;
1500 if(fCurrentVertex->GetNContributors()>0) {
1501 indices = new UShort_t[fCurrentVertex->GetNContributors()];
1502 for(Int_t jj=0; jj<(Int_t)fTrkArraySel.GetEntriesFast(); jj++) {
1503 indices[jj] = fIdSel[jj];
1504 t = (AliExternalTrackParam*)fTrkArraySel.At(jj);
1505 if(optPropagate && optUseFitter) {
1506 if(TMath::Sqrt(fCurrentVertex->GetXv()*fCurrentVertex->GetXv()+fCurrentVertex->GetYv()*fCurrentVertex->GetYv())<3.) {
1507 t->PropagateToDCA(fCurrentVertex,GetFieldkG(),100.,d0z0,covd0z0);
1508 if(fDebug) printf("Track %d propagated to found vertex\n",jj);
1510 AliWarning("Found vertex outside beam pipe!");
1514 fCurrentVertex->SetIndices(fCurrentVertex->GetNContributors(),indices);
1518 delete [] indices; indices=NULL;
1519 delete [] fIdSel; fIdSel=NULL;
1520 fTrkArraySel.Delete();
1522 return fCurrentVertex;
1524 //----------------------------------------------------------------------------
1525 AliESDVertex* AliVertexerTracks::VertexForSelectedESDTracks(TObjArray *trkArray,
1526 Bool_t optUseFitter,
1527 Bool_t optPropagate)
1530 // Return vertex from array of ESD tracks
1533 Int_t nTrks = (Int_t)trkArray->GetEntriesFast();
1534 UShort_t *id = new UShort_t[nTrks];
1536 AliESDtrack *esdt = 0;
1537 for(Int_t i=0; i<nTrks; i++){
1538 esdt = (AliESDtrack*)trkArray->At(i);
1539 id[i] = (UShort_t)esdt->GetID();
1542 VertexForSelectedTracks(trkArray,id,optUseFitter,optPropagate);
1544 delete [] id; id=NULL;
1546 return fCurrentVertex;
1548 //--------------------------------------------------------------------------