]> git.uio.no Git - u/mrichter/AliRoot.git/blame - STEER/AliVertexerTracks.cxx
git://git.uio.no / u / mrichter / AliRoot.git / blame
? search:
summary | shortlog | log | commit | commitdiff | tree
blob | blame (incremental) | history | HEAD
Fix effc++ warnings and most blatant coding-convention violations.
[u/mrichter/AliRoot.git] / STEER / AliVertexerTracks.cxx
CommitLineData
2d57349e 1/**************************************************************************
2 * Copyright(c) 1998-2003, ALICE Experiment at CERN, All rights reserved. *
3 * *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
6 * *
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 **************************************************************************/
15
16//-----------------------------------------------------------------
17// Implementation of the vertexer from ESD tracks
18//
19// Origin: AliITSVertexerTracks
20// A.Dainese, Padova,
21// andrea.dainese@pd.infn.it
22// M.Masera, Torino,
23// massimo.masera@to.infn.it
24// Moved to STEER and adapted to ESD tracks:
25// F.Prino, Torino, prino@to.infn.it
26//-----------------------------------------------------------------
27
28//---- Root headers --------
29#include <TTree.h>
ec1be5d5 30#include <TMatrixD.h>
2d57349e 31//---- AliRoot headers -----
32#include "AliStrLine.h"
33#include "AliVertexerTracks.h"
c5e3e5d1 34#include "AliESD.h"
2d57349e 35#include "AliESDtrack.h"
36
37ClassImp(AliVertexerTracks)
38
39
40//----------------------------------------------------------------------------
41AliVertexerTracks::AliVertexerTracks():
07680cae 42TObject(),
43fVert(),
44fCurrentVertex(0),
07680cae 45fTrkArray(),
46fTrksToSkip(0),
47fNTrksToSkip(0),
48fDCAcut(0),
49fAlgo(1),
50fDebug(0)
2d57349e 51{
52//
53// Default constructor
54//
55 SetVtxStart();
07680cae 56 SetVtxStartSigma();
2d57349e 57 SetMinTracks();
07680cae 58 SetMinITSClusters();
59 SetNSigmad0();
2d57349e 60}
61//-----------------------------------------------------------------------------
62AliVertexerTracks::AliVertexerTracks(Double_t xStart, Double_t yStart):
07680cae 63TObject(),
64fVert(),
65fCurrentVertex(0),
07680cae 66fTrkArray(),
67fTrksToSkip(0),
68fNTrksToSkip(0),
69fDCAcut(0),
70fAlgo(1),
71fDebug(0)
2d57349e 72{
73//
74// Standard constructor
75//
76 SetVtxStart(xStart,yStart);
07680cae 77 SetVtxStartSigma();
2d57349e 78 SetMinTracks();
07680cae 79 SetMinITSClusters();
80 SetNSigmad0();
2d57349e 81}
82//-----------------------------------------------------------------------------
83AliVertexerTracks::~AliVertexerTracks() {
84 // Default Destructor
eae1677e 85 // The objects pointed by the following pointer are not owned
2d57349e 86 // by this class and are not deleted
ec1be5d5 87 fCurrentVertex = 0;
07680cae 88 delete[] fTrksToSkip;
ec1be5d5 89}
90//---------------------------------------------------------------------------
91void AliVertexerTracks::SetSkipTracks(Int_t n,Int_t *skipped) {
92//
93// Mark the tracks not ot be used in the vertex finding
94//
95 fNTrksToSkip = n;
96 fTrksToSkip = new Int_t[n];
97 for(Int_t i=0;i<n;i++) fTrksToSkip[i] = skipped[i];
98 return;
99}
2d57349e 100//----------------------------------------------------------------------------
ec1be5d5 101Int_t AliVertexerTracks::PrepareTracks(TTree &trkTree, Int_t OptImpParCut) {
2d57349e 102//
103// Propagate tracks to initial vertex position and store them in a TObjArray
104//
ec1be5d5 105 Double_t maxd0rphi = 3.;
2d57349e 106 Int_t nTrks = 0;
07680cae 107 Double_t sigmaCurr[3],sigmaVtx[3],posVtx[3];
eae1677e 108 Double_t covVtx[6],covVtxXY;
07680cae 109 Float_t d0z0[2],covd0z0[3];
110 Double_t momentum[3],postrk[3];
111 Double_t pt,sigma,sigmavtxphi,phitrk;
ec1be5d5 112 Double_t field=GetField();
2d57349e 113
07680cae 114 AliESDVertex *initVertex = new AliESDVertex(fNominalPos,fNominalSigma);
115
2d57349e 116 Int_t nEntries = (Int_t)trkTree.GetEntries();
117 if(!fTrkArray.IsEmpty()) fTrkArray.Clear();
118 fTrkArray.Expand(nEntries);
119
ec1be5d5 120 if(fDebug) {
121 printf(" PrepareTracks()\n");
122 }
123
2d57349e 124 for(Int_t i=0; i<nEntries; i++) {
125 AliESDtrack *track = new AliESDtrack;
126 trkTree.SetBranchAddress("tracks",&track);
127 trkTree.GetEvent(i);
128
07680cae 129
130
131 // propagate track to vertex
eae1677e 132 if(OptImpParCut==1) { // OptImpParCut==1
07680cae 133 track->RelateToVertex(initVertex,field,100.);
134 initVertex->GetXYZ(posVtx);
135 initVertex->GetSigmaXYZ(sigmaVtx);
eae1677e 136 covVtxXY = 0.;
137 } else { // OptImpParCut==2
07680cae 138 fCurrentVertex->GetSigmaXYZ(sigmaCurr);
139 if((sigmaCurr[0]+sigmaCurr[1])<(fNominalSigma[0]+fNominalSigma[1])) {
140 track->RelateToVertex(fCurrentVertex,field,100.);
141 fCurrentVertex->GetXYZ(posVtx);
142 fCurrentVertex->GetSigmaXYZ(sigmaVtx);
eae1677e 143 fCurrentVertex->GetCovMatrix(covVtx);
144 covVtxXY = covVtx[1];
07680cae 145 } else {
146 track->RelateToVertex(initVertex,field,100.);
147 initVertex->GetXYZ(posVtx);
148 initVertex->GetSigmaXYZ(sigmaVtx);
eae1677e 149 covVtxXY = 0.;
07680cae 150 }
151 }
152
153 // select tracks with d0rphi < maxd0rphi
154 track->GetImpactParameters(d0z0,covd0z0);
155
eae1677e 156 track->GetXYZ(postrk);
157 track->GetPxPyPz(momentum);
158 pt = TMath::Sqrt(momentum[0]*momentum[0]+momentum[1]*momentum[1]);
159
160 phitrk = TMath::ATan2(postrk[1]-posVtx[1],postrk[0]-posVtx[0]);
161 sigmavtxphi = TMath::Sqrt(sigmaVtx[0]*sigmaVtx[0]*
162 TMath::Cos(phitrk)*TMath::Cos(phitrk)+
163 sigmaVtx[1]*sigmaVtx[1]*
164 TMath::Sin(phitrk)*TMath::Sin(phitrk)+
165 covVtxXY*
166 TMath::Cos(phitrk)*TMath::Sin(phitrk));
167 sigma = TMath::Sqrt(Sigmad0rphi(pt)*Sigmad0rphi(pt)+
168 sigmavtxphi*sigmavtxphi);
169 maxd0rphi = fNSigma*sigma;
170 if(OptImpParCut==1) maxd0rphi *= 5.;
171
172 if(fDebug) printf("trk %d; lab %d; |d0| = %f; cut = %f\n",i,track->GetLabel(),TMath::Abs(d0z0[0]),maxd0rphi);
07680cae 173 if(TMath::Abs(d0z0[0]) > maxd0rphi) {
eae1677e 174 if(fDebug) printf(" rejected\n");
07680cae 175 delete track; continue;
176 }
177
2d57349e 178 fTrkArray.AddLast(track);
179 nTrks++;
180 }
07680cae 181
07680cae 182 delete initVertex;
183
2d57349e 184 return nTrks;
185}
186//----------------------------------------------------------------------------
07680cae 187Double_t AliVertexerTracks::Sigmad0rphi(Double_t pt) const {
188//
189// Impact parameter resolution in rphi [cm] vs pt [GeV/c]
190//
191 Double_t a_meas = 11.6;
192 Double_t a_scatt = 65.8;
193 Double_t b = 1.878;
194
195 Double_t sigma = a_meas*a_meas+a_scatt*a_scatt/TMath::Power(pt,b);
196 sigma = 0.0001*TMath::Sqrt(sigma);
197
198 return sigma;
199}
200//----------------------------------------------------------------------------
2d57349e 201AliVertex* AliVertexerTracks::VertexForSelectedTracks(TTree *trkTree) {
202//
203// Return vertex from tracks in trkTree
204//
205
206 // get tracks and propagate them to initial vertex position
ec1be5d5 207 Int_t nTrks = PrepareTracks(*trkTree,1);
2d57349e 208 if(nTrks < fMinTracks) {
209 printf("TooFewTracks\n");
210 Double_t vtx[3]={0,0,0};
211 fVert.SetXYZ(vtx);
212 fVert.SetDispersion(999);
213 fVert.SetNContributors(-5);
214 return &fVert;
215 }
216
217 // Set initial vertex position from ESD
218 if(fAlgo==1) StrLinVertexFinderMinDist(1);
219 if(fAlgo==2) StrLinVertexFinderMinDist(0);
220 if(fAlgo==3) HelixVertexFinder();
221 if(fAlgo==4) VertexFinder(1);
222 if(fAlgo==5) VertexFinder(0);
223 return &fVert;
224}
c5e3e5d1 225//----------------------------------------------------------------------------
ec1be5d5 226AliESDVertex* AliVertexerTracks::FindPrimaryVertex(const AliESD *esdEvent)
227{
c5e3e5d1 228//
ec1be5d5 229// Primary vertex for current ESD event
eae1677e 230// (Two iterations:
231// 1st with 5*fNSigma*sigma(pt) cut w.r.t. to initial vertex;
232// 2nd with fNSigma*sigma(pt) cut w.r.t. to vertex found in 1st iteration)
07680cae 233//
234 fCurrentVertex = 0;
235
236 Int_t entr = (Int_t)esdEvent->GetNumberOfTracks();
237 TTree *trkTree = new TTree("TreeT","tracks");
238 AliESDtrack *esdTrack = 0;
239 trkTree->Branch("tracks","AliESDtrack",&esdTrack);
240
eae1677e 241 Bool_t skipThis;
07680cae 242 for(Int_t i=0; i<entr; i++) {
eae1677e 243 // check tracks to skip
244 skipThis = kFALSE;
245 for(Int_t j=0; j<fNTrksToSkip; j++) {
246 if(i==fTrksToSkip[j]) {
247 if(fDebug) printf("skipping track: %d\n",i);
248 skipThis = kTRUE;
249 }
250 }
251 if(skipThis) continue;
07680cae 252 AliESDtrack *et = esdEvent->GetTrack(i);
253 esdTrack = new AliESDtrack(*et);
254 if(!esdTrack->GetStatus()&AliESDtrack::kITSin) continue;
255 if(!esdTrack->GetStatus()&AliESDtrack::kITSrefit) continue;
256 Int_t nclus=esdTrack->GetNcls(0); // check number of clusters in ITS
257 if(nclus<fMinITSClusters) continue;
07680cae 258 trkTree->Fill();
259 }
260 delete esdTrack;
261
262 // ITERATION 1
263 // propagate tracks to initVertex
eae1677e 264 // preselect them (reject for |d0|>5*fNSigma*sigma w.r.t. initVertex)
07680cae 265 Int_t nTrks;
266 nTrks = PrepareTracks(*trkTree,1);
267 if(fDebug) printf(" tracks prepared - step 1: %d\n",nTrks);
268 if(nTrks < fMinTracks) {
269 printf("TooFewTracks\n");
eae1677e 270 TooFewTracks(esdEvent);
271 if(fDebug) fCurrentVertex->PrintStatus();
07680cae 272 return fCurrentVertex;
273 }
274
275 // vertex finder
276 switch (fAlgo) {
277 case 1: StrLinVertexFinderMinDist(1); break;
278 case 2: StrLinVertexFinderMinDist(0); break;
279 case 3: HelixVertexFinder(); break;
280 case 4: VertexFinder(1); break;
281 case 5: VertexFinder(0); break;
282 default: printf("Wrong algorithm\n"); break;
283 }
284 if(fDebug) printf(" vertex finding completed\n");
285
286 // vertex fitter
eae1677e 287 VertexFitter(kTRUE);
07680cae 288 if(fDebug) printf(" vertex fit completed\n");
289
290 // ITERATION 2
291 // propagate tracks to best between initVertex and fCurrentVertex
292 // preselect tracks (reject for |d0|>fNSigma*sigma w.r.t. best
293 // between initVertex and fCurrentVertex)
294 nTrks = PrepareTracks(*trkTree,2);
295 delete trkTree;
296 if(fDebug) printf(" tracks prepared - step 2: %d\n",nTrks);
297 if(nTrks < fMinTracks) {
298 printf("TooFewTracks\n");
eae1677e 299 TooFewTracks(esdEvent);
300 if(fDebug) fCurrentVertex->PrintStatus();
07680cae 301 return fCurrentVertex;
302 }
303
304 // vertex finder
305 switch (fAlgo) {
306 case 1: StrLinVertexFinderMinDist(1); break;
307 case 2: StrLinVertexFinderMinDist(0); break;
308 case 3: HelixVertexFinder(); break;
309 case 4: VertexFinder(1); break;
310 case 5: VertexFinder(0); break;
311 default: printf("Wrong algorithm\n"); break;
312 }
313 if(fDebug) printf(" vertex finding completed\n");
314
315 // fitter
eae1677e 316 VertexFitter(kTRUE);
07680cae 317 if(fDebug) printf(" vertex fit completed\n");
318
eae1677e 319
320 fTrkArray.Clear();
321
322 // take true pos from ESD
07680cae 323 Double_t tp[3];
324 esdEvent->GetVertex()->GetTruePos(tp);
325 fCurrentVertex->SetTruePos(tp);
eae1677e 326 if(fNominalSigma[0]>1.) {
327 fCurrentVertex->SetTitle("VertexerTracksNoConstraint");
328 } else {
329 fCurrentVertex->SetTitle("VertexerTracksWithConstraint");
330 }
331
332 if(fDebug) fCurrentVertex->PrintStatus();
333 if(fTrksToSkip) delete [] fTrksToSkip;
07680cae 334
07680cae 335 return fCurrentVertex;
336}
337//----------------------------------------------------------------------------
338AliESDVertex* AliVertexerTracks::FindPrimaryVertexOld(const AliESD *esdEvent)
339{
340//
341// Primary vertex for current ESD event (one iteration with |d0rphi|<3cm)
c5e3e5d1 342//
ec1be5d5 343 fCurrentVertex = 0;
344
345 Int_t entr = (Int_t)esdEvent->GetNumberOfTracks();
346 TTree *trkTree = new TTree("TreeT","tracks");
347 AliESDtrack *esdTrack = 0;
348 trkTree->Branch("tracks","AliESDtrack",&esdTrack);
349
350 for(Int_t i=0; i<entr; i++) {
351 AliESDtrack *et = esdEvent->GetTrack(i);
352 esdTrack = new AliESDtrack(*et);
353 if(!esdTrack->GetStatus()&AliESDtrack::kITSin) continue;
354 if(!esdTrack->GetStatus()&AliESDtrack::kITSrefit) continue;
355 Int_t nclus=esdTrack->GetNcls(0); // check number of clusters in ITS
07680cae 356 if(nclus<fMinITSClusters) continue;
ec1be5d5 357
358 trkTree->Fill();
c5e3e5d1 359 }
ec1be5d5 360 delete esdTrack;
c5e3e5d1 361
ec1be5d5 362 // preselect tracks and propagate them to initial vertex position
07680cae 363 Int_t nTrks = PrepareTracks(*trkTree,1);
ec1be5d5 364 delete trkTree;
365 if(fDebug) printf(" tracks prepared: %d\n",nTrks);
366 if(nTrks < fMinTracks) {
c5e3e5d1 367 printf("TooFewTracks\n");
ec1be5d5 368 fCurrentVertex = new AliESDVertex(0.,0.,-1);
369 return fCurrentVertex;
370 }
c5e3e5d1 371
ec1be5d5 372 // VERTEX FINDER
373 switch (fAlgo) {
374 case 1: StrLinVertexFinderMinDist(1); break;
375 case 2: StrLinVertexFinderMinDist(0); break;
376 case 3: HelixVertexFinder(); break;
377 case 4: VertexFinder(1); break;
378 case 5: VertexFinder(0); break;
379 default: printf("Wrong algorithm\n"); break;
380 }
c5e3e5d1 381
ec1be5d5 382 // VERTEX FITTER
ec1be5d5 383 VertexFitter();
384 if(fDebug) printf(" vertex fit completed\n");
c5e3e5d1 385
ec1be5d5 386
387 Double_t tp[3];
388 esdEvent->GetVertex()->GetTruePos(tp);
389 fCurrentVertex->SetTruePos(tp);
390 fCurrentVertex->SetTitle("VertexerTracks");
391
392 fTrkArray.Clear();
393 return fCurrentVertex;
394}
2d57349e 395//----------------------------------------------------------------------------
396AliVertex* AliVertexerTracks::VertexForSelectedTracks(TObjArray *trkArray) {
397//
398// Return vertex from array of tracks
399//
400
401 // get tracks and propagate them to initial vertex position
402 Int_t nTrks = trkArray->GetEntriesFast();
403 if(nTrks < fMinTracks) {
404 printf("TooFewTracks\n");
405 Double_t vtx[3]={0,0,0};
406 fVert.SetXYZ(vtx);
407 fVert.SetDispersion(999);
408 fVert.SetNContributors(-5);
409 return &fVert;
410 }
411 TTree *trkTree = new TTree("TreeT","tracks");
412 AliESDtrack *esdTrack = 0;
413 trkTree->Branch("tracks","AliESDtrack",&esdTrack);
414 for(Int_t i=0; i<nTrks; i++){
415 esdTrack = (AliESDtrack*)trkArray->At(i);
416 trkTree->Fill();
417 }
418
2e5c8fc7 419 AliVertex *vtx = VertexForSelectedTracks(trkTree);
420 delete trkTree;
421 return vtx;
2d57349e 422}
423
424//---------------------------------------------------------------------------
425void AliVertexerTracks::VertexFinder(Int_t optUseWeights) {
426
427 // Get estimate of vertex position in (x,y) from tracks DCA
428
429 Double_t initPos[3];
430 initPos[2] = 0.;
431 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
432 Int_t nacc = (Int_t)fTrkArray.GetEntriesFast();
433 Double_t aver[3]={0.,0.,0.};
434 Double_t aversq[3]={0.,0.,0.};
435 Double_t sigmasq[3]={0.,0.,0.};
436 Double_t sigma=0;
437 Int_t ncombi = 0;
438 AliESDtrack *track1;
439 AliESDtrack *track2;
ec1be5d5 440 Double_t pos[3],dir[3];
2d57349e 441 Double_t alpha,mindist;
442 Double_t field=GetField();
443
444 for(Int_t i=0; i<nacc; i++){
445 track1 = (AliESDtrack*)fTrkArray.At(i);
446 alpha=track1->GetAlpha();
447 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
ec1be5d5 448 track1->GetXYZAt(mindist,field,pos);
449 track1->GetPxPyPzAt(mindist,field,dir);
450 AliStrLine *line1 = new AliStrLine(pos,dir);
08df6187 451
ec1be5d5 452 // AliStrLine *line1 = new AliStrLine();
453 // track1->ApproximateHelixWithLine(mindist,field,line1);
2d57349e 454
455 for(Int_t j=i+1; j<nacc; j++){
456 track2 = (AliESDtrack*)fTrkArray.At(j);
457 alpha=track2->GetAlpha();
458 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
ec1be5d5 459 track2->GetXYZAt(mindist,field,pos);
460 track2->GetPxPyPzAt(mindist,field,dir);
461 AliStrLine *line2 = new AliStrLine(pos,dir);
462 // AliStrLine *line2 = new AliStrLine();
463 // track2->ApproximateHelixWithLine(mindist,field,line2);
2d57349e 464 Double_t distCA=line2->GetDCA(line1);
465 if(fDCAcut<=0 || (fDCAcut>0&&distCA<fDCAcut)){
466 Double_t pnt1[3],pnt2[3],crosspoint[3];
467
468 if(optUseWeights<=0){
469 Int_t retcode = line2->Cross(line1,crosspoint);
470 if(retcode>=0){
471 ncombi++;
472 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
473 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
474 }
475 }
476 if(optUseWeights>0){
477 Int_t retcode = line1->CrossPoints(line2,pnt1,pnt2);
478 if(retcode>=0){
479 Double_t alpha, cs, sn;
480 alpha=track1->GetAlpha();
481 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
482 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
483 alpha=track2->GetAlpha();
484 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
485 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
486 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
487 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
488 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
489 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
490 crosspoint[0]=wx1*pnt1[0] + wx2*pnt2[0];
491 crosspoint[1]=wy1*pnt1[1] + wy2*pnt2[1];
492 crosspoint[2]=wz1*pnt1[2] + wz2*pnt2[2];
493
494 ncombi++;
495 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
496 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
497 }
498 }
499 }
500 delete line2;
501 }
502 delete line1;
503 }
504 if(ncombi>0){
505 for(Int_t jj=0;jj<3;jj++){
506 initPos[jj] = aver[jj]/ncombi;
507 aversq[jj]/=ncombi;
508 sigmasq[jj]=aversq[jj]-initPos[jj]*initPos[jj];
509 sigma+=sigmasq[jj];
510 }
511 sigma=TMath::Sqrt(TMath::Abs(sigma));
512 }
513 else {
514 Warning("VertexFinder","Finder did not succed");
515 sigma=999;
516 }
517 fVert.SetXYZ(initPos);
518 fVert.SetDispersion(sigma);
519 fVert.SetNContributors(ncombi);
520}
521//---------------------------------------------------------------------------
522void AliVertexerTracks::HelixVertexFinder() {
523
524 // Get estimate of vertex position in (x,y) from tracks DCA
525
526
527 Double_t initPos[3];
528 initPos[2] = 0.;
529 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
530 Double_t field=GetField();
531
532 Int_t nacc = (Int_t)fTrkArray.GetEntriesFast();
533
534 Double_t aver[3]={0.,0.,0.};
535 Double_t averquad[3]={0.,0.,0.};
536 Double_t sigmaquad[3]={0.,0.,0.};
537 Double_t sigma=0;
538 Int_t ncombi = 0;
539 AliESDtrack *track1;
540 AliESDtrack *track2;
541 Double_t distCA;
542 Double_t x, par[5];
543 Double_t alpha, cs, sn;
544 Double_t crosspoint[3];
545 for(Int_t i=0; i<nacc; i++){
546 track1 = (AliESDtrack*)fTrkArray.At(i);
547
548
549 for(Int_t j=i+1; j<nacc; j++){
550 track2 = (AliESDtrack*)fTrkArray.At(j);
551
552 distCA=track2->PropagateToDCA(track1,field);
553
554 if(fDCAcut<=0 ||(fDCAcut>0&&distCA<fDCAcut)){
555 track1->GetExternalParameters(x,par);
556 alpha=track1->GetAlpha();
557 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
558 Double_t x1=x*cs - par[0]*sn;
559 Double_t y1=x*sn + par[0]*cs;
560 Double_t z1=par[1];
561 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
562 track2->GetExternalParameters(x,par);
563 alpha=track2->GetAlpha();
564 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
565 Double_t x2=x*cs - par[0]*sn;
566 Double_t y2=x*sn + par[0]*cs;
567 Double_t z2=par[1];
568 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
569 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
570 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
571 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
572 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
573 crosspoint[0]=wx1*x1 + wx2*x2;
574 crosspoint[1]=wy1*y1 + wy2*y2;
575 crosspoint[2]=wz1*z1 + wz2*z2;
576
577 ncombi++;
578 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
579 for(Int_t jj=0;jj<3;jj++)averquad[jj]+=(crosspoint[jj]*crosspoint[jj]);
580 }
581 }
582
583 }
584 if(ncombi>0){
585 for(Int_t jj=0;jj<3;jj++){
586 initPos[jj] = aver[jj]/ncombi;
587 averquad[jj]/=ncombi;
588 sigmaquad[jj]=averquad[jj]-initPos[jj]*initPos[jj];
589 sigma+=sigmaquad[jj];
590 }
591 sigma=TMath::Sqrt(TMath::Abs(sigma));
592 }
593 else {
594 Warning("HelixVertexFinder","Finder did not succed");
595 sigma=999;
596 }
597 fVert.SetXYZ(initPos);
598 fVert.SetDispersion(sigma);
599 fVert.SetNContributors(ncombi);
600}
601//---------------------------------------------------------------------------
602void AliVertexerTracks::StrLinVertexFinderMinDist(Int_t optUseWeights){
603
604 // Calculate the point at minimum distance to prepared tracks
605
606 Double_t initPos[3];
607 initPos[2] = 0.;
608 Double_t sigma=0;
609 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
610 const Int_t knacc = (Int_t)fTrkArray.GetEntriesFast();
611 Double_t field=GetField();
612
613 AliESDtrack *track1;
614 Double_t (*vectP0)[3]=new Double_t [knacc][3];
615 Double_t (*vectP1)[3]=new Double_t [knacc][3];
616
617 Double_t sum[3][3];
618 Double_t dsum[3]={0,0,0};
619 for(Int_t i=0;i<3;i++)
620 for(Int_t j=0;j<3;j++)sum[i][j]=0;
621 for(Int_t i=0; i<knacc; i++){
622 track1 = (AliESDtrack*)fTrkArray.At(i);
623 Double_t alpha=track1->GetAlpha();
624 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
ec1be5d5 625 Double_t pos[3],dir[3];
626 track1->GetXYZAt(mindist,field,pos);
627 track1->GetPxPyPzAt(mindist,field,dir);
628 AliStrLine *line1 = new AliStrLine(pos,dir);
629 // AliStrLine *line1 = new AliStrLine();
630 // track1->ApproximateHelixWithLine(mindist,field,line1);
2d57349e 631
632 Double_t p0[3],cd[3];
633 line1->GetP0(p0);
634 line1->GetCd(cd);
635 Double_t p1[3]={p0[0]+cd[0],p0[1]+cd[1],p0[2]+cd[2]};
636 vectP0[i][0]=p0[0];
637 vectP0[i][1]=p0[1];
638 vectP0[i][2]=p0[2];
639 vectP1[i][0]=p1[0];
640 vectP1[i][1]=p1[1];
641 vectP1[i][2]=p1[2];
642
643 Double_t matr[3][3];
644 Double_t dknow[3];
645 if(optUseWeights==0)GetStrLinDerivMatrix(p0,p1,matr,dknow);
646 if(optUseWeights==1){
647 Double_t sigmasq[3];
648 sigmasq[0]=track1->GetSigmaY2();
649 sigmasq[1]=track1->GetSigmaY2();
650 sigmasq[2]=track1->GetSigmaZ2();
651 GetStrLinDerivMatrix(p0,p1,sigmasq,matr,dknow);
652 }
653
654 for(Int_t iii=0;iii<3;iii++){
655 dsum[iii]+=dknow[iii];
656 for(Int_t lj=0;lj<3;lj++) sum[iii][lj]+=matr[iii][lj];
657 }
658 delete line1;
659 }
660
661 Double_t vett[3][3];
662 Double_t det=GetDeterminant3X3(sum);
663
664 if(det!=0){
665 for(Int_t zz=0;zz<3;zz++){
666 for(Int_t ww=0;ww<3;ww++){
667 for(Int_t kk=0;kk<3;kk++) vett[ww][kk]=sum[ww][kk];
668 }
669 for(Int_t kk=0;kk<3;kk++) vett[kk][zz]=dsum[kk];
670 initPos[zz]=GetDeterminant3X3(vett)/det;
671 }
672
673
674 for(Int_t i=0; i<knacc; i++){
675 Double_t p0[3]={0,0,0},p1[3]={0,0,0};
676 for(Int_t ii=0;ii<3;ii++){
677 p0[ii]=vectP0[i][ii];
678 p1[ii]=vectP1[i][ii];
679 }
680 sigma+=GetStrLinMinDist(p0,p1,initPos);
681 }
682
683 sigma=TMath::Sqrt(sigma);
684 }else{
685 Warning("StrLinVertexFinderMinDist","Finder did not succed");
686 sigma=999;
687 }
688 delete vectP0;
689 delete vectP1;
690 fVert.SetXYZ(initPos);
691 fVert.SetDispersion(sigma);
692 fVert.SetNContributors(knacc);
693}
694//_______________________________________________________________________
695Double_t AliVertexerTracks::GetDeterminant3X3(Double_t matr[][3]){
696 //
697 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];
698 return det;
699}
700//____________________________________________________________________________
71d84967 701void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t (*m)[3],Double_t *d){
2d57349e 702
703 //
704 Double_t x12=p0[0]-p1[0];
705 Double_t y12=p0[1]-p1[1];
706 Double_t z12=p0[2]-p1[2];
707 Double_t kk=x12*x12+y12*y12+z12*z12;
708 m[0][0]=2-2/kk*x12*x12;
709 m[0][1]=-2/kk*x12*y12;
710 m[0][2]=-2/kk*x12*z12;
711 m[1][0]=-2/kk*x12*y12;
712 m[1][1]=2-2/kk*y12*y12;
713 m[1][2]=-2/kk*y12*z12;
714 m[2][0]=-2/kk*x12*z12;
715 m[2][1]=-2*y12*z12;
716 m[2][2]=2-2/kk*z12*z12;
717 d[0]=2*p0[0]-2/kk*p0[0]*x12*x12-2/kk*p0[2]*x12*z12-2/kk*p0[1]*x12*y12;
718 d[1]=2*p0[1]-2/kk*p0[1]*y12*y12-2/kk*p0[0]*x12*y12-2/kk*p0[2]*z12*y12;
719 d[2]=2*p0[2]-2/kk*p0[2]*z12*z12-2/kk*p0[0]*x12*z12-2/kk*p0[1]*z12*y12;
720
721}
722//____________________________________________________________________________
71d84967 723void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t *sigmasq,Double_t (*m)[3],Double_t *d){
2d57349e 724 //
725 Double_t x12=p1[0]-p0[0];
726 Double_t y12=p1[1]-p0[1];
727 Double_t z12=p1[2]-p0[2];
728
729 Double_t den= x12*x12*sigmasq[1]*sigmasq[2]+y12*y12*sigmasq[0]*sigmasq[2]+z12*z12*sigmasq[0]*sigmasq[1];
730
731 Double_t kk= 2*(x12*x12/sigmasq[0]+y12*y12/sigmasq[1]+z12*z12/sigmasq[2]);
732
733 Double_t cc[3];
734 cc[0]=-x12/sigmasq[0];
735 cc[1]=-y12/sigmasq[1];
736 cc[2]=-z12/sigmasq[2];
737
738 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;
739
740 Double_t ss= -p0[0]*cc[0]-p0[1]*cc[1]-p0[2]*cc[2];
741
742 Double_t aa[3];
743 aa[0]=x12*sigmasq[1]*sigmasq[2]/den;
744 aa[1]=y12*sigmasq[0]*sigmasq[2]/den;
745 aa[2]=z12*sigmasq[0]*sigmasq[1]/den;
746
747 m[0][0]=aa[0]*(aa[0]*kk+2*cc[0])+2*cc[0]*aa[0]+2/sigmasq[0];
748 m[0][1]=aa[1]*(aa[0]*kk+2*cc[0])+2*cc[1]*aa[0];
749 m[0][2]=aa[2]*(aa[0]*kk+2*cc[0])+2*cc[2]*aa[0];
750
751 m[1][0]=aa[0]*(aa[1]*kk+2*cc[1])+2*cc[0]*aa[1];
752 m[1][1]=aa[1]*(aa[1]*kk+2*cc[1])+2*cc[1]*aa[1]+2/sigmasq[1];
753 m[1][2]=aa[2]*(aa[1]*kk+2*cc[1])+2*cc[2]*aa[1];
754
755 m[2][0]=aa[0]*(aa[2]*kk+2*cc[2])+2*cc[0]*aa[2];
756 m[2][1]=aa[1]*(aa[2]*kk+2*cc[2])+2*cc[1]*aa[2];
757 m[2][2]=aa[2]*(aa[2]*kk+2*cc[2])+2*cc[2]*aa[2]+2/sigmasq[2];
758
759 d[0]=-ww*(aa[0]*kk+2*cc[0])-2*ss*aa[0]+2*p0[0]/sigmasq[0];
760 d[1]=-ww*(aa[1]*kk+2*cc[1])-2*ss*aa[1]+2*p0[1]/sigmasq[1];
761 d[2]=-ww*(aa[2]*kk+2*cc[2])-2*ss*aa[2]+2*p0[2]/sigmasq[2];
762
71d84967 763 }
2d57349e 764//_____________________________________________________________________________
765Double_t AliVertexerTracks::GetStrLinMinDist(Double_t *p0,Double_t *p1,Double_t *x0){
766 //
767 Double_t x12=p0[0]-p1[0];
768 Double_t y12=p0[1]-p1[1];
769 Double_t z12=p0[2]-p1[2];
770 Double_t x10=p0[0]-x0[0];
771 Double_t y10=p0[1]-x0[1];
772 Double_t z10=p0[2]-x0[2];
773 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);
774}
ec1be5d5 775//---------------------------------------------------------------------------
07680cae 776void AliVertexerTracks::VertexFitter(Bool_t useNominalVtx) {
ec1be5d5 777//
778// The optimal estimate of the vertex position is given by a "weighted
779// average of tracks positions"
780// Original method: CMS Note 97/0051
781//
782 Double_t initPos[3];
783 fVert.GetXYZ(initPos);
784 if(fDebug) {
785 printf(" VertexFitter(): start\n");
786 printf(" Number of tracks in array: %d\n",(Int_t)fTrkArray.GetEntriesFast());
787 printf(" Minimum # tracks required in fit: %d\n",fMinTracks);
788 printf("Vertex position after finder: %f,%f,%f\n",initPos[0],initPos[1],initPos[2]);
eae1677e 789 if(useNominalVtx) printf(" This vertex will be used in fit: (%f+-%f,%f+-%f)\n",fNominalPos[0],fNominalSigma[0],fNominalPos[1],fNominalSigma[1]);
ec1be5d5 790 }
791
792 Int_t i,j,k,step=0;
793 TMatrixD rv(3,1);
794 TMatrixD vV(3,3);
795 rv(0,0) = initPos[0];
796 rv(1,0) = initPos[1];
797 rv(2,0) = 0.;
798 Double_t xlStart,alpha;
799 Double_t rotAngle;
800 Double_t cosRot,sinRot;
801 Double_t cc[15];
802 Int_t nUsedTrks;
803 Double_t chi2,chi2i;
804 Int_t arrEntries = (Int_t)fTrkArray.GetEntries();
805 AliESDtrack *t = 0;
806 Int_t failed = 0;
807
eae1677e 808 // 2 steps:
809 // 1st - estimate of vtx using all tracks
810 // 2nd - estimate of global chi2
811 for(step=0; step<2; step++) {
ec1be5d5 812 if(fDebug) printf(" step = %d\n",step);
813 chi2 = 0.;
814 nUsedTrks = 0;
815
816 TMatrixD sumWiri(3,1);
817 TMatrixD sumWi(3,3);
818 for(i=0; i<3; i++) {
819 sumWiri(i,0) = 0.;
820 for(j=0; j<3; j++) sumWi(j,i) = 0.;
821 }
822
07680cae 823 if(useNominalVtx) {
824 for(i=0; i<3; i++) {
825 sumWiri(i,0) += fNominalPos[i]/fNominalSigma[i]/fNominalSigma[i];
826 sumWi(i,i) += 1./fNominalSigma[i]/fNominalSigma[i];
827 }
828 }
829
830
ec1be5d5 831 // loop on tracks
832 for(k=0; k<arrEntries; k++) {
ec1be5d5 833 // get track from track array
834 t = (AliESDtrack*)fTrkArray.At(k);
835 alpha = t->GetAlpha();
836 xlStart = initPos[0]*TMath::Cos(alpha)+initPos[1]*TMath::Sin(alpha);
837 t->PropagateTo(xlStart,AliTracker::GetBz()); // to vtxSeed
838 rotAngle = alpha;
839 if(alpha<0.) rotAngle += 2.*TMath::Pi();
840 cosRot = TMath::Cos(rotAngle);
841 sinRot = TMath::Sin(rotAngle);
842
843 // vector of track global coordinates
844 TMatrixD ri(3,1);
845 ri(0,0) = t->GetX()*cosRot-t->GetY()*sinRot;
846 ri(1,0) = t->GetX()*sinRot+t->GetY()*cosRot;
847 ri(2,0) = t->GetZ();
848
849 // matrix to go from global (x,y,z) to local (y,z);
850 TMatrixD qQi(2,3);
851 qQi(0,0) = -sinRot;
852 qQi(0,1) = cosRot;
853 qQi(0,2) = 0.;
854 qQi(1,0) = 0.;
855 qQi(1,1) = 0.;
856 qQi(1,2) = 1.;
857
858 // covariance matrix of local (y,z) - inverted
859 TMatrixD uUi(2,2);
860 t->GetExternalCovariance(cc);
861 uUi(0,0) = cc[0];
862 uUi(0,1) = cc[1];
863 uUi(1,0) = cc[1];
864 uUi(1,1) = cc[2];
865
866 // weights matrix: wWi = qQiT * uUiInv * qQi
867 if(uUi.Determinant() <= 0.) continue;
868 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
869 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
870 TMatrixD wWi(qQi,TMatrixD::kTransposeMult,uUiInvQi);
871
872 // track chi2
873 TMatrixD deltar = rv; deltar -= ri;
874 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
875 chi2i = deltar(0,0)*wWideltar(0,0)+
876 deltar(1,0)*wWideltar(1,0)+
877 deltar(2,0)*wWideltar(2,0);
878
879
ec1be5d5 880 // add to total chi2
881 chi2 += chi2i;
882
883 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
884
885 sumWiri += wWiri;
886 sumWi += wWi;
887
888 nUsedTrks++;
889 } // end loop on tracks
890
891 if(nUsedTrks < fMinTracks) {
892 failed=1;
893 continue;
894 }
895
896 Double_t determinant = sumWi.Determinant();
897 //cerr<<" determinant: "<<determinant<<endl;
898 if(determinant < 100.) {
899 printf("det(V) = 0\n");
900 failed=1;
901 continue;
902 }
903
904 // inverted of weights matrix
905 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
906 vV = invsumWi;
907
908 // position of primary vertex
909 rv.Mult(vV,sumWiri);
910
eae1677e 911 } // end loop on the 2 steps
ec1be5d5 912
ec1be5d5 913 delete t;
914
915 if(failed) {
916 printf("TooFewTracks\n");
917 fCurrentVertex = new AliESDVertex(0.,0.,-1);
918 return;
919 }
920
921 Double_t position[3];
922 position[0] = rv(0,0);
923 position[1] = rv(1,0);
924 position[2] = rv(2,0);
925 Double_t covmatrix[6];
926 covmatrix[0] = vV(0,0);
927 covmatrix[1] = vV(0,1);
928 covmatrix[2] = vV(1,1);
929 covmatrix[3] = vV(0,2);
930 covmatrix[4] = vV(1,2);
931 covmatrix[5] = vV(2,2);
932
933 // store data in the vertex object
934 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nUsedTrks);
935
936 if(fDebug) {
937 printf(" VertexFitter(): finish\n");
938 printf(" rv = ( %f , %f , %f )\n\n",rv(0,0),rv(1,0),rv(2,0));
939 fCurrentVertex->PrintStatus();
940 }
941
942 return;
943}
eae1677e 944//---------------------------------------------------------------------------
945void AliVertexerTracks::TooFewTracks(const AliESD* esdEvent) {
946//
947// When the number of tracks is < fMinTracks
948//
949
950 // deal with vertices not found
951 Double_t pos[3],err[3];
952 Int_t ncontr=0;
953 pos[0] = fNominalPos[0];
954 err[0] = fNominalSigma[0];
955 pos[1] = fNominalPos[1];
956 err[1] = fNominalSigma[1];
957 pos[2] = esdEvent->GetVertex()->GetZv();
958 err[2] = esdEvent->GetVertex()->GetZRes();
959 if(err[0]>1. && esdEvent->GetVertex()->GetNContributors()<=0)
960 ncontr = -1; // (x,y,z) = (0,0,0)
961 if(err[0]>1. && esdEvent->GetVertex()->GetNContributors()>0)
962 ncontr = -2; // (x,y,z) = (0,0,z_fromSPD)
963 if(err[0]<1. && esdEvent->GetVertex()->GetNContributors()<=0)
964 ncontr = -3; // (x,y,z) = (x_mean,y_mean,0)
965 if(err[0]<1. && esdEvent->GetVertex()->GetNContributors()>0)
966 ncontr = -4; // (x,y,z) = (x_mean,y_mean,z_fromSPD)
967 fCurrentVertex = 0;
968 fCurrentVertex = new AliESDVertex(pos,err);
969 fCurrentVertex->SetNContributors(ncontr);
970
971 Double_t tp[3];
972 esdEvent->GetVertex()->GetTruePos(tp);
973 fCurrentVertex->SetTruePos(tp);
974 fCurrentVertex->SetTitle("VertexerTracksWithConstraint");
975 if(ncontr==-1||ncontr==-2)
976 fCurrentVertex->SetTitle("VertexerTracksNoConstraint");
977
978 return;
979}