]> git.uio.no Git - u/mrichter/AliRoot.git/blame_incremental - STEER/AliVertexerTracks.cxx
git://git.uio.no / u / mrichter / AliRoot.git / blame_incremental
? search:
summary | shortlog | log | commit | commitdiff | tree
blob | blame (non-incremental) | history | HEAD
Fixing some problems in the CDB access (Alberto)
[u/mrichter/AliRoot.git] / STEER / AliVertexerTracks.cxx
... / ...
CommitLineData
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>
30#include <TMatrixD.h>
31//---- AliRoot headers -----
32#include "AliStrLine.h"
33#include "AliVertexerTracks.h"
34#include "AliESD.h"
35#include "AliESDtrack.h"
36
37ClassImp(AliVertexerTracks)
38
39
40//----------------------------------------------------------------------------
41AliVertexerTracks::AliVertexerTracks():
42TObject(),
43fVert(),
44fCurrentVertex(0),
45fMinTracks(2),
46fMinITSClusters(5),
47fTrkArray(),
48fTrksToSkip(0),
49fNTrksToSkip(0),
50fDCAcut(0),
51fAlgo(1),
52fNSigma(3),
53fDebug(0)
54{
55//
56// Default constructor
57//
58 SetVtxStart();
59 SetVtxStartSigma();
60 SetMinTracks();
61 SetMinITSClusters();
62 SetNSigmad0();
63}
64//-----------------------------------------------------------------------------
65AliVertexerTracks::AliVertexerTracks(Double_t xStart, Double_t yStart):
66TObject(),
67fVert(),
68fCurrentVertex(0),
69fMinTracks(2),
70fMinITSClusters(5),
71fTrkArray(),
72fTrksToSkip(0),
73fNTrksToSkip(0),
74fDCAcut(0),
75fAlgo(1),
76fNSigma(3),
77fDebug(0)
78{
79//
80// Standard constructor
81//
82 SetVtxStart(xStart,yStart);
83 SetVtxStartSigma();
84 SetMinTracks();
85 SetMinITSClusters();
86 SetNSigmad0();
87}
88//-----------------------------------------------------------------------------
89AliVertexerTracks::~AliVertexerTracks() {
90 // Default Destructor
91 // The objects pointed by the following pointer are not owned
92 // by this class and are not deleted
93 fCurrentVertex = 0;
94 delete[] fTrksToSkip;
95}
96//---------------------------------------------------------------------------
97void AliVertexerTracks::SetSkipTracks(Int_t n,Int_t *skipped) {
98//
99// Mark the tracks not ot be used in the vertex finding
100//
101 fNTrksToSkip = n;
102 fTrksToSkip = new Int_t[n];
103 for(Int_t i=0;i<n;i++) fTrksToSkip[i] = skipped[i];
104 return;
105}
106//----------------------------------------------------------------------------
107Int_t AliVertexerTracks::PrepareTracks(TTree &trkTree, Int_t OptImpParCut) {
108//
109// Propagate tracks to initial vertex position and store them in a TObjArray
110//
111 Double_t maxd0rphi = 3.;
112 Int_t nTrks = 0;
113 Double_t sigmaCurr[3],sigmaVtx[3],posVtx[3];
114 Double_t covVtx[6],covVtxXY;
115 Float_t d0z0[2],covd0z0[3];
116 Double_t momentum[3],postrk[3];
117 Double_t pt,sigma,sigmavtxphi,phitrk;
118 Double_t field=GetField();
119
120 AliESDVertex *initVertex = new AliESDVertex(fNominalPos,fNominalSigma);
121
122 Int_t nEntries = (Int_t)trkTree.GetEntries();
123 if(!fTrkArray.IsEmpty()) fTrkArray.Clear();
124 fTrkArray.Expand(nEntries);
125
126 if(fDebug) {
127 printf(" PrepareTracks()\n");
128 }
129
130 for(Int_t i=0; i<nEntries; i++) {
131 AliESDtrack *track = new AliESDtrack;
132 trkTree.SetBranchAddress("tracks",&track);
133 trkTree.GetEvent(i);
134
135
136
137 // propagate track to vertex
138 if(OptImpParCut==1) { // OptImpParCut==1
139 track->RelateToVertex(initVertex,field,100.);
140 initVertex->GetXYZ(posVtx);
141 initVertex->GetSigmaXYZ(sigmaVtx);
142 covVtxXY = 0.;
143 } else { // OptImpParCut==2
144 fCurrentVertex->GetSigmaXYZ(sigmaCurr);
145 if((sigmaCurr[0]+sigmaCurr[1])<(fNominalSigma[0]+fNominalSigma[1])) {
146 track->RelateToVertex(fCurrentVertex,field,100.);
147 fCurrentVertex->GetXYZ(posVtx);
148 fCurrentVertex->GetSigmaXYZ(sigmaVtx);
149 fCurrentVertex->GetCovMatrix(covVtx);
150 covVtxXY = covVtx[1];
151 } else {
152 track->RelateToVertex(initVertex,field,100.);
153 initVertex->GetXYZ(posVtx);
154 initVertex->GetSigmaXYZ(sigmaVtx);
155 covVtxXY = 0.;
156 }
157 }
158
159 // select tracks with d0rphi < maxd0rphi
160 track->GetImpactParameters(d0z0,covd0z0);
161
162 track->GetXYZ(postrk);
163 track->GetPxPyPz(momentum);
164 pt = TMath::Sqrt(momentum[0]*momentum[0]+momentum[1]*momentum[1]);
165
166 phitrk = TMath::ATan2(postrk[1]-posVtx[1],postrk[0]-posVtx[0]);
167 sigmavtxphi = TMath::Sqrt(sigmaVtx[0]*sigmaVtx[0]*
168 TMath::Cos(phitrk)*TMath::Cos(phitrk)+
169 sigmaVtx[1]*sigmaVtx[1]*
170 TMath::Sin(phitrk)*TMath::Sin(phitrk)+
171 covVtxXY*
172 TMath::Cos(phitrk)*TMath::Sin(phitrk));
173 sigma = TMath::Sqrt(Sigmad0rphi(pt)*Sigmad0rphi(pt)+
174 sigmavtxphi*sigmavtxphi);
175 maxd0rphi = fNSigma*sigma;
176 if(OptImpParCut==1) maxd0rphi *= 5.;
177
178 if(fDebug) printf("trk %d; lab %d; |d0| = %f; cut = %f\n",i,track->GetLabel(),TMath::Abs(d0z0[0]),maxd0rphi);
179 if(TMath::Abs(d0z0[0]) > maxd0rphi) {
180 if(fDebug) printf(" rejected\n");
181 delete track; continue;
182 }
183
184 fTrkArray.AddLast(track);
185 nTrks++;
186 }
187
188 delete initVertex;
189
190 return nTrks;
191}
192//----------------------------------------------------------------------------
193Double_t AliVertexerTracks::Sigmad0rphi(Double_t pt) const {
194//
195// Impact parameter resolution in rphi [cm] vs pt [GeV/c]
196//
197 Double_t a_meas = 11.6;
198 Double_t a_scatt = 65.8;
199 Double_t b = 1.878;
200
201 Double_t sigma = a_meas*a_meas+a_scatt*a_scatt/TMath::Power(pt,b);
202 sigma = 0.0001*TMath::Sqrt(sigma);
203
204 return sigma;
205}
206//----------------------------------------------------------------------------
207AliVertex* AliVertexerTracks::VertexForSelectedTracks(TTree *trkTree) {
208//
209// Return vertex from tracks in trkTree
210//
211
212 // get tracks and propagate them to initial vertex position
213 Int_t nTrks = PrepareTracks(*trkTree,1);
214 if(nTrks < fMinTracks) {
215 printf("TooFewTracks\n");
216 Double_t vtx[3]={0,0,0};
217 fVert.SetXYZ(vtx);
218 fVert.SetDispersion(999);
219 fVert.SetNContributors(-5);
220 return &fVert;
221 }
222
223 // Set initial vertex position from ESD
224 if(fAlgo==1) StrLinVertexFinderMinDist(1);
225 if(fAlgo==2) StrLinVertexFinderMinDist(0);
226 if(fAlgo==3) HelixVertexFinder();
227 if(fAlgo==4) VertexFinder(1);
228 if(fAlgo==5) VertexFinder(0);
229 return &fVert;
230}
231//----------------------------------------------------------------------------
232AliESDVertex* AliVertexerTracks::FindPrimaryVertex(const AliESD *esdEvent)
233{
234//
235// Primary vertex for current ESD event
236// (Two iterations:
237// 1st with 5*fNSigma*sigma(pt) cut w.r.t. to initial vertex;
238// 2nd with fNSigma*sigma(pt) cut w.r.t. to vertex found in 1st iteration)
239//
240 fCurrentVertex = 0;
241
242 Int_t entr = (Int_t)esdEvent->GetNumberOfTracks();
243 TTree *trkTree = new TTree("TreeT","tracks");
244 AliESDtrack *esdTrack = 0;
245 trkTree->Branch("tracks","AliESDtrack",&esdTrack);
246
247 Bool_t skipThis;
248 for(Int_t i=0; i<entr; i++) {
249 // check tracks to skip
250 skipThis = kFALSE;
251 for(Int_t j=0; j<fNTrksToSkip; j++) {
252 if(i==fTrksToSkip[j]) {
253 if(fDebug) printf("skipping track: %d\n",i);
254 skipThis = kTRUE;
255 }
256 }
257 if(skipThis) continue;
258 AliESDtrack *et = esdEvent->GetTrack(i);
259 esdTrack = new AliESDtrack(*et);
260 if(!esdTrack->GetStatus()&AliESDtrack::kITSin) continue;
261 if(!esdTrack->GetStatus()&AliESDtrack::kITSrefit) continue;
262 Int_t nclus=esdTrack->GetNcls(0); // check number of clusters in ITS
263 if(nclus<fMinITSClusters) continue;
264 trkTree->Fill();
265 }
266 delete esdTrack;
267
268 // ITERATION 1
269 // propagate tracks to initVertex
270 // preselect them (reject for |d0|>5*fNSigma*sigma w.r.t. initVertex)
271 Int_t nTrks;
272 nTrks = PrepareTracks(*trkTree,1);
273 if(fDebug) printf(" tracks prepared - step 1: %d\n",nTrks);
274 if(nTrks < fMinTracks) {
275 printf("TooFewTracks\n");
276 TooFewTracks(esdEvent);
277 if(fDebug) fCurrentVertex->PrintStatus();
278 return fCurrentVertex;
279 }
280
281 // vertex finder
282 switch (fAlgo) {
283 case 1: StrLinVertexFinderMinDist(1); break;
284 case 2: StrLinVertexFinderMinDist(0); break;
285 case 3: HelixVertexFinder(); break;
286 case 4: VertexFinder(1); break;
287 case 5: VertexFinder(0); break;
288 default: printf("Wrong algorithm\n"); break;
289 }
290 if(fDebug) printf(" vertex finding completed\n");
291
292 // vertex fitter
293 VertexFitter(kTRUE);
294 if(fDebug) printf(" vertex fit completed\n");
295
296 // ITERATION 2
297 // propagate tracks to best between initVertex and fCurrentVertex
298 // preselect tracks (reject for |d0|>fNSigma*sigma w.r.t. best
299 // between initVertex and fCurrentVertex)
300 nTrks = PrepareTracks(*trkTree,2);
301 delete trkTree;
302 if(fDebug) printf(" tracks prepared - step 2: %d\n",nTrks);
303 if(nTrks < fMinTracks) {
304 printf("TooFewTracks\n");
305 TooFewTracks(esdEvent);
306 if(fDebug) fCurrentVertex->PrintStatus();
307 return fCurrentVertex;
308 }
309
310 // vertex finder
311 switch (fAlgo) {
312 case 1: StrLinVertexFinderMinDist(1); break;
313 case 2: StrLinVertexFinderMinDist(0); break;
314 case 3: HelixVertexFinder(); break;
315 case 4: VertexFinder(1); break;
316 case 5: VertexFinder(0); break;
317 default: printf("Wrong algorithm\n"); break;
318 }
319 if(fDebug) printf(" vertex finding completed\n");
320
321 // fitter
322 VertexFitter(kTRUE);
323 if(fDebug) printf(" vertex fit completed\n");
324
325
326 fTrkArray.Clear();
327
328 // take true pos from ESD
329 Double_t tp[3];
330 esdEvent->GetVertex()->GetTruePos(tp);
331 fCurrentVertex->SetTruePos(tp);
332 if(fNominalSigma[0]>1.) {
333 fCurrentVertex->SetTitle("VertexerTracksNoConstraint");
334 } else {
335 fCurrentVertex->SetTitle("VertexerTracksWithConstraint");
336 }
337
338 if(fDebug) fCurrentVertex->PrintStatus();
339 if(fTrksToSkip) delete [] fTrksToSkip;
340
341 return fCurrentVertex;
342}
343//----------------------------------------------------------------------------
344AliESDVertex* AliVertexerTracks::FindPrimaryVertexOld(const AliESD *esdEvent)
345{
346//
347// Primary vertex for current ESD event (one iteration with |d0rphi|<3cm)
348//
349 fCurrentVertex = 0;
350
351 Int_t entr = (Int_t)esdEvent->GetNumberOfTracks();
352 TTree *trkTree = new TTree("TreeT","tracks");
353 AliESDtrack *esdTrack = 0;
354 trkTree->Branch("tracks","AliESDtrack",&esdTrack);
355
356 for(Int_t i=0; i<entr; i++) {
357 AliESDtrack *et = esdEvent->GetTrack(i);
358 esdTrack = new AliESDtrack(*et);
359 if(!esdTrack->GetStatus()&AliESDtrack::kITSin) continue;
360 if(!esdTrack->GetStatus()&AliESDtrack::kITSrefit) continue;
361 Int_t nclus=esdTrack->GetNcls(0); // check number of clusters in ITS
362 if(nclus<fMinITSClusters) continue;
363
364 trkTree->Fill();
365 }
366 delete esdTrack;
367
368 // preselect tracks and propagate them to initial vertex position
369 Int_t nTrks = PrepareTracks(*trkTree,1);
370 delete trkTree;
371 if(fDebug) printf(" tracks prepared: %d\n",nTrks);
372 if(nTrks < fMinTracks) {
373 printf("TooFewTracks\n");
374 fCurrentVertex = new AliESDVertex(0.,0.,-1);
375 return fCurrentVertex;
376 }
377
378 // VERTEX FINDER
379 switch (fAlgo) {
380 case 1: StrLinVertexFinderMinDist(1); break;
381 case 2: StrLinVertexFinderMinDist(0); break;
382 case 3: HelixVertexFinder(); break;
383 case 4: VertexFinder(1); break;
384 case 5: VertexFinder(0); break;
385 default: printf("Wrong algorithm\n"); break;
386 }
387
388 // VERTEX FITTER
389 VertexFitter();
390 if(fDebug) printf(" vertex fit completed\n");
391
392
393 Double_t tp[3];
394 esdEvent->GetVertex()->GetTruePos(tp);
395 fCurrentVertex->SetTruePos(tp);
396 fCurrentVertex->SetTitle("VertexerTracks");
397
398 fTrkArray.Clear();
399 return fCurrentVertex;
400}
401//----------------------------------------------------------------------------
402AliVertex* AliVertexerTracks::VertexForSelectedTracks(TObjArray *trkArray) {
403//
404// Return vertex from array of tracks
405//
406
407 // get tracks and propagate them to initial vertex position
408 Int_t nTrks = trkArray->GetEntriesFast();
409 if(nTrks < fMinTracks) {
410 printf("TooFewTracks\n");
411 Double_t vtx[3]={0,0,0};
412 fVert.SetXYZ(vtx);
413 fVert.SetDispersion(999);
414 fVert.SetNContributors(-5);
415 return &fVert;
416 }
417 TTree *trkTree = new TTree("TreeT","tracks");
418 AliESDtrack *esdTrack = 0;
419 trkTree->Branch("tracks","AliESDtrack",&esdTrack);
420 for(Int_t i=0; i<nTrks; i++){
421 esdTrack = (AliESDtrack*)trkArray->At(i);
422 trkTree->Fill();
423 }
424
425 AliVertex *vtx = VertexForSelectedTracks(trkTree);
426 delete trkTree;
427 return vtx;
428}
429
430//---------------------------------------------------------------------------
431void AliVertexerTracks::VertexFinder(Int_t optUseWeights) {
432
433 // Get estimate of vertex position in (x,y) from tracks DCA
434
435 Double_t initPos[3];
436 initPos[2] = 0.;
437 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
438 Int_t nacc = (Int_t)fTrkArray.GetEntriesFast();
439 Double_t aver[3]={0.,0.,0.};
440 Double_t aversq[3]={0.,0.,0.};
441 Double_t sigmasq[3]={0.,0.,0.};
442 Double_t sigma=0;
443 Int_t ncombi = 0;
444 AliESDtrack *track1;
445 AliESDtrack *track2;
446 Double_t pos[3],dir[3];
447 Double_t alpha,mindist;
448 Double_t field=GetField();
449
450 for(Int_t i=0; i<nacc; i++){
451 track1 = (AliESDtrack*)fTrkArray.At(i);
452 alpha=track1->GetAlpha();
453 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
454 track1->GetXYZAt(mindist,field,pos);
455 track1->GetPxPyPzAt(mindist,field,dir);
456 AliStrLine *line1 = new AliStrLine(pos,dir);
457
458 // AliStrLine *line1 = new AliStrLine();
459 // track1->ApproximateHelixWithLine(mindist,field,line1);
460
461 for(Int_t j=i+1; j<nacc; j++){
462 track2 = (AliESDtrack*)fTrkArray.At(j);
463 alpha=track2->GetAlpha();
464 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
465 track2->GetXYZAt(mindist,field,pos);
466 track2->GetPxPyPzAt(mindist,field,dir);
467 AliStrLine *line2 = new AliStrLine(pos,dir);
468 // AliStrLine *line2 = new AliStrLine();
469 // track2->ApproximateHelixWithLine(mindist,field,line2);
470 Double_t distCA=line2->GetDCA(line1);
471 if(fDCAcut<=0 || (fDCAcut>0&&distCA<fDCAcut)){
472 Double_t pnt1[3],pnt2[3],crosspoint[3];
473
474 if(optUseWeights<=0){
475 Int_t retcode = line2->Cross(line1,crosspoint);
476 if(retcode>=0){
477 ncombi++;
478 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
479 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
480 }
481 }
482 if(optUseWeights>0){
483 Int_t retcode = line1->CrossPoints(line2,pnt1,pnt2);
484 if(retcode>=0){
485 Double_t alpha, cs, sn;
486 alpha=track1->GetAlpha();
487 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
488 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
489 alpha=track2->GetAlpha();
490 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
491 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
492 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
493 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
494 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
495 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
496 crosspoint[0]=wx1*pnt1[0] + wx2*pnt2[0];
497 crosspoint[1]=wy1*pnt1[1] + wy2*pnt2[1];
498 crosspoint[2]=wz1*pnt1[2] + wz2*pnt2[2];
499
500 ncombi++;
501 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
502 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
503 }
504 }
505 }
506 delete line2;
507 }
508 delete line1;
509 }
510 if(ncombi>0){
511 for(Int_t jj=0;jj<3;jj++){
512 initPos[jj] = aver[jj]/ncombi;
513 aversq[jj]/=ncombi;
514 sigmasq[jj]=aversq[jj]-initPos[jj]*initPos[jj];
515 sigma+=sigmasq[jj];
516 }
517 sigma=TMath::Sqrt(TMath::Abs(sigma));
518 }
519 else {
520 Warning("VertexFinder","Finder did not succed");
521 sigma=999;
522 }
523 fVert.SetXYZ(initPos);
524 fVert.SetDispersion(sigma);
525 fVert.SetNContributors(ncombi);
526}
527//---------------------------------------------------------------------------
528void AliVertexerTracks::HelixVertexFinder() {
529
530 // Get estimate of vertex position in (x,y) from tracks DCA
531
532
533 Double_t initPos[3];
534 initPos[2] = 0.;
535 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
536 Double_t field=GetField();
537
538 Int_t nacc = (Int_t)fTrkArray.GetEntriesFast();
539
540 Double_t aver[3]={0.,0.,0.};
541 Double_t averquad[3]={0.,0.,0.};
542 Double_t sigmaquad[3]={0.,0.,0.};
543 Double_t sigma=0;
544 Int_t ncombi = 0;
545 AliESDtrack *track1;
546 AliESDtrack *track2;
547 Double_t distCA;
548 Double_t x, par[5];
549 Double_t alpha, cs, sn;
550 Double_t crosspoint[3];
551 for(Int_t i=0; i<nacc; i++){
552 track1 = (AliESDtrack*)fTrkArray.At(i);
553
554
555 for(Int_t j=i+1; j<nacc; j++){
556 track2 = (AliESDtrack*)fTrkArray.At(j);
557
558 distCA=track2->PropagateToDCA(track1,field);
559
560 if(fDCAcut<=0 ||(fDCAcut>0&&distCA<fDCAcut)){
561 track1->GetExternalParameters(x,par);
562 alpha=track1->GetAlpha();
563 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
564 Double_t x1=x*cs - par[0]*sn;
565 Double_t y1=x*sn + par[0]*cs;
566 Double_t z1=par[1];
567 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
568 track2->GetExternalParameters(x,par);
569 alpha=track2->GetAlpha();
570 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
571 Double_t x2=x*cs - par[0]*sn;
572 Double_t y2=x*sn + par[0]*cs;
573 Double_t z2=par[1];
574 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
575 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
576 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
577 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
578 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
579 crosspoint[0]=wx1*x1 + wx2*x2;
580 crosspoint[1]=wy1*y1 + wy2*y2;
581 crosspoint[2]=wz1*z1 + wz2*z2;
582
583 ncombi++;
584 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
585 for(Int_t jj=0;jj<3;jj++)averquad[jj]+=(crosspoint[jj]*crosspoint[jj]);
586 }
587 }
588
589 }
590 if(ncombi>0){
591 for(Int_t jj=0;jj<3;jj++){
592 initPos[jj] = aver[jj]/ncombi;
593 averquad[jj]/=ncombi;
594 sigmaquad[jj]=averquad[jj]-initPos[jj]*initPos[jj];
595 sigma+=sigmaquad[jj];
596 }
597 sigma=TMath::Sqrt(TMath::Abs(sigma));
598 }
599 else {
600 Warning("HelixVertexFinder","Finder did not succed");
601 sigma=999;
602 }
603 fVert.SetXYZ(initPos);
604 fVert.SetDispersion(sigma);
605 fVert.SetNContributors(ncombi);
606}
607//---------------------------------------------------------------------------
608void AliVertexerTracks::StrLinVertexFinderMinDist(Int_t optUseWeights){
609
610 // Calculate the point at minimum distance to prepared tracks
611
612 Double_t initPos[3];
613 initPos[2] = 0.;
614 Double_t sigma=0;
615 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
616 const Int_t knacc = (Int_t)fTrkArray.GetEntriesFast();
617 Double_t field=GetField();
618
619 AliESDtrack *track1;
620 Double_t (*vectP0)[3]=new Double_t [knacc][3];
621 Double_t (*vectP1)[3]=new Double_t [knacc][3];
622
623 Double_t sum[3][3];
624 Double_t dsum[3]={0,0,0};
625 for(Int_t i=0;i<3;i++)
626 for(Int_t j=0;j<3;j++)sum[i][j]=0;
627 for(Int_t i=0; i<knacc; i++){
628 track1 = (AliESDtrack*)fTrkArray.At(i);
629 Double_t alpha=track1->GetAlpha();
630 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
631 Double_t pos[3],dir[3];
632 track1->GetXYZAt(mindist,field,pos);
633 track1->GetPxPyPzAt(mindist,field,dir);
634 AliStrLine *line1 = new AliStrLine(pos,dir);
635 // AliStrLine *line1 = new AliStrLine();
636 // track1->ApproximateHelixWithLine(mindist,field,line1);
637
638 Double_t p0[3],cd[3];
639 line1->GetP0(p0);
640 line1->GetCd(cd);
641 Double_t p1[3]={p0[0]+cd[0],p0[1]+cd[1],p0[2]+cd[2]};
642 vectP0[i][0]=p0[0];
643 vectP0[i][1]=p0[1];
644 vectP0[i][2]=p0[2];
645 vectP1[i][0]=p1[0];
646 vectP1[i][1]=p1[1];
647 vectP1[i][2]=p1[2];
648
649 Double_t matr[3][3];
650 Double_t dknow[3];
651 if(optUseWeights==0)GetStrLinDerivMatrix(p0,p1,matr,dknow);
652 if(optUseWeights==1){
653 Double_t sigmasq[3];
654 sigmasq[0]=track1->GetSigmaY2();
655 sigmasq[1]=track1->GetSigmaY2();
656 sigmasq[2]=track1->GetSigmaZ2();
657 GetStrLinDerivMatrix(p0,p1,sigmasq,matr,dknow);
658 }
659
660 for(Int_t iii=0;iii<3;iii++){
661 dsum[iii]+=dknow[iii];
662 for(Int_t lj=0;lj<3;lj++) sum[iii][lj]+=matr[iii][lj];
663 }
664 delete line1;
665 }
666
667 Double_t vett[3][3];
668 Double_t det=GetDeterminant3X3(sum);
669
670 if(det!=0){
671 for(Int_t zz=0;zz<3;zz++){
672 for(Int_t ww=0;ww<3;ww++){
673 for(Int_t kk=0;kk<3;kk++) vett[ww][kk]=sum[ww][kk];
674 }
675 for(Int_t kk=0;kk<3;kk++) vett[kk][zz]=dsum[kk];
676 initPos[zz]=GetDeterminant3X3(vett)/det;
677 }
678
679
680 for(Int_t i=0; i<knacc; i++){
681 Double_t p0[3]={0,0,0},p1[3]={0,0,0};
682 for(Int_t ii=0;ii<3;ii++){
683 p0[ii]=vectP0[i][ii];
684 p1[ii]=vectP1[i][ii];
685 }
686 sigma+=GetStrLinMinDist(p0,p1,initPos);
687 }
688
689 sigma=TMath::Sqrt(sigma);
690 }else{
691 Warning("StrLinVertexFinderMinDist","Finder did not succed");
692 sigma=999;
693 }
694 delete vectP0;
695 delete vectP1;
696 fVert.SetXYZ(initPos);
697 fVert.SetDispersion(sigma);
698 fVert.SetNContributors(knacc);
699}
700//_______________________________________________________________________
701Double_t AliVertexerTracks::GetDeterminant3X3(Double_t matr[][3]){
702 //
703 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];
704 return det;
705}
706//____________________________________________________________________________
707void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t (*m)[3],Double_t *d){
708
709 //
710 Double_t x12=p0[0]-p1[0];
711 Double_t y12=p0[1]-p1[1];
712 Double_t z12=p0[2]-p1[2];
713 Double_t kk=x12*x12+y12*y12+z12*z12;
714 m[0][0]=2-2/kk*x12*x12;
715 m[0][1]=-2/kk*x12*y12;
716 m[0][2]=-2/kk*x12*z12;
717 m[1][0]=-2/kk*x12*y12;
718 m[1][1]=2-2/kk*y12*y12;
719 m[1][2]=-2/kk*y12*z12;
720 m[2][0]=-2/kk*x12*z12;
721 m[2][1]=-2*y12*z12;
722 m[2][2]=2-2/kk*z12*z12;
723 d[0]=2*p0[0]-2/kk*p0[0]*x12*x12-2/kk*p0[2]*x12*z12-2/kk*p0[1]*x12*y12;
724 d[1]=2*p0[1]-2/kk*p0[1]*y12*y12-2/kk*p0[0]*x12*y12-2/kk*p0[2]*z12*y12;
725 d[2]=2*p0[2]-2/kk*p0[2]*z12*z12-2/kk*p0[0]*x12*z12-2/kk*p0[1]*z12*y12;
726
727}
728//____________________________________________________________________________
729void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t *sigmasq,Double_t (*m)[3],Double_t *d){
730 //
731 Double_t x12=p1[0]-p0[0];
732 Double_t y12=p1[1]-p0[1];
733 Double_t z12=p1[2]-p0[2];
734
735 Double_t den= x12*x12*sigmasq[1]*sigmasq[2]+y12*y12*sigmasq[0]*sigmasq[2]+z12*z12*sigmasq[0]*sigmasq[1];
736
737 Double_t kk= 2*(x12*x12/sigmasq[0]+y12*y12/sigmasq[1]+z12*z12/sigmasq[2]);
738
739 Double_t cc[3];
740 cc[0]=-x12/sigmasq[0];
741 cc[1]=-y12/sigmasq[1];
742 cc[2]=-z12/sigmasq[2];
743
744 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;
745
746 Double_t ss= -p0[0]*cc[0]-p0[1]*cc[1]-p0[2]*cc[2];
747
748 Double_t aa[3];
749 aa[0]=x12*sigmasq[1]*sigmasq[2]/den;
750 aa[1]=y12*sigmasq[0]*sigmasq[2]/den;
751 aa[2]=z12*sigmasq[0]*sigmasq[1]/den;
752
753 m[0][0]=aa[0]*(aa[0]*kk+2*cc[0])+2*cc[0]*aa[0]+2/sigmasq[0];
754 m[0][1]=aa[1]*(aa[0]*kk+2*cc[0])+2*cc[1]*aa[0];
755 m[0][2]=aa[2]*(aa[0]*kk+2*cc[0])+2*cc[2]*aa[0];
756
757 m[1][0]=aa[0]*(aa[1]*kk+2*cc[1])+2*cc[0]*aa[1];
758 m[1][1]=aa[1]*(aa[1]*kk+2*cc[1])+2*cc[1]*aa[1]+2/sigmasq[1];
759 m[1][2]=aa[2]*(aa[1]*kk+2*cc[1])+2*cc[2]*aa[1];
760
761 m[2][0]=aa[0]*(aa[2]*kk+2*cc[2])+2*cc[0]*aa[2];
762 m[2][1]=aa[1]*(aa[2]*kk+2*cc[2])+2*cc[1]*aa[2];
763 m[2][2]=aa[2]*(aa[2]*kk+2*cc[2])+2*cc[2]*aa[2]+2/sigmasq[2];
764
765 d[0]=-ww*(aa[0]*kk+2*cc[0])-2*ss*aa[0]+2*p0[0]/sigmasq[0];
766 d[1]=-ww*(aa[1]*kk+2*cc[1])-2*ss*aa[1]+2*p0[1]/sigmasq[1];
767 d[2]=-ww*(aa[2]*kk+2*cc[2])-2*ss*aa[2]+2*p0[2]/sigmasq[2];
768
769 }
770//_____________________________________________________________________________
771Double_t AliVertexerTracks::GetStrLinMinDist(Double_t *p0,Double_t *p1,Double_t *x0){
772 //
773 Double_t x12=p0[0]-p1[0];
774 Double_t y12=p0[1]-p1[1];
775 Double_t z12=p0[2]-p1[2];
776 Double_t x10=p0[0]-x0[0];
777 Double_t y10=p0[1]-x0[1];
778 Double_t z10=p0[2]-x0[2];
779 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);
780}
781//---------------------------------------------------------------------------
782void AliVertexerTracks::VertexFitter(Bool_t useNominalVtx) {
783//
784// The optimal estimate of the vertex position is given by a "weighted
785// average of tracks positions"
786// Original method: CMS Note 97/0051
787//
788 Double_t initPos[3];
789 fVert.GetXYZ(initPos);
790 if(fDebug) {
791 printf(" VertexFitter(): start\n");
792 printf(" Number of tracks in array: %d\n",(Int_t)fTrkArray.GetEntriesFast());
793 printf(" Minimum # tracks required in fit: %d\n",fMinTracks);
794 printf("Vertex position after finder: %f,%f,%f\n",initPos[0],initPos[1],initPos[2]);
795 if(useNominalVtx) printf(" This vertex will be used in fit: (%f+-%f,%f+-%f)\n",fNominalPos[0],fNominalSigma[0],fNominalPos[1],fNominalSigma[1]);
796 }
797
798 Int_t i,j,k,step=0;
799 TMatrixD rv(3,1);
800 TMatrixD vV(3,3);
801 rv(0,0) = initPos[0];
802 rv(1,0) = initPos[1];
803 rv(2,0) = 0.;
804 Double_t xlStart,alpha;
805 Double_t rotAngle;
806 Double_t cosRot,sinRot;
807 Double_t cc[15];
808 Int_t nUsedTrks;
809 Double_t chi2,chi2i;
810 Int_t arrEntries = (Int_t)fTrkArray.GetEntries();
811 AliESDtrack *t = 0;
812 Int_t failed = 0;
813
814 // 2 steps:
815 // 1st - estimate of vtx using all tracks
816 // 2nd - estimate of global chi2
817 for(step=0; step<2; step++) {
818 if(fDebug) printf(" step = %d\n",step);
819 chi2 = 0.;
820 nUsedTrks = 0;
821
822 TMatrixD sumWiri(3,1);
823 TMatrixD sumWi(3,3);
824 for(i=0; i<3; i++) {
825 sumWiri(i,0) = 0.;
826 for(j=0; j<3; j++) sumWi(j,i) = 0.;
827 }
828
829 if(useNominalVtx) {
830 for(i=0; i<3; i++) {
831 sumWiri(i,0) += fNominalPos[i]/fNominalSigma[i]/fNominalSigma[i];
832 sumWi(i,i) += 1./fNominalSigma[i]/fNominalSigma[i];
833 }
834 }
835
836
837 // loop on tracks
838 for(k=0; k<arrEntries; k++) {
839 // get track from track array
840 t = (AliESDtrack*)fTrkArray.At(k);
841 alpha = t->GetAlpha();
842 xlStart = initPos[0]*TMath::Cos(alpha)+initPos[1]*TMath::Sin(alpha);
843 t->AliExternalTrackParam::PropagateTo(xlStart,AliTracker::GetBz()); // to vtxSeed
844 rotAngle = alpha;
845 if(alpha<0.) rotAngle += 2.*TMath::Pi();
846 cosRot = TMath::Cos(rotAngle);
847 sinRot = TMath::Sin(rotAngle);
848
849 // vector of track global coordinates
850 TMatrixD ri(3,1);
851 ri(0,0) = t->GetX()*cosRot-t->GetY()*sinRot;
852 ri(1,0) = t->GetX()*sinRot+t->GetY()*cosRot;
853 ri(2,0) = t->GetZ();
854
855 // matrix to go from global (x,y,z) to local (y,z);
856 TMatrixD qQi(2,3);
857 qQi(0,0) = -sinRot;
858 qQi(0,1) = cosRot;
859 qQi(0,2) = 0.;
860 qQi(1,0) = 0.;
861 qQi(1,1) = 0.;
862 qQi(1,2) = 1.;
863
864 // covariance matrix of local (y,z) - inverted
865 TMatrixD uUi(2,2);
866 t->GetExternalCovariance(cc);
867 uUi(0,0) = cc[0];
868 uUi(0,1) = cc[1];
869 uUi(1,0) = cc[1];
870 uUi(1,1) = cc[2];
871
872 // weights matrix: wWi = qQiT * uUiInv * qQi
873 if(uUi.Determinant() <= 0.) continue;
874 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
875 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
876 TMatrixD wWi(qQi,TMatrixD::kTransposeMult,uUiInvQi);
877
878 // track chi2
879 TMatrixD deltar = rv; deltar -= ri;
880 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
881 chi2i = deltar(0,0)*wWideltar(0,0)+
882 deltar(1,0)*wWideltar(1,0)+
883 deltar(2,0)*wWideltar(2,0);
884
885
886 // add to total chi2
887 chi2 += chi2i;
888
889 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
890
891 sumWiri += wWiri;
892 sumWi += wWi;
893
894 nUsedTrks++;
895 } // end loop on tracks
896
897 if(nUsedTrks < fMinTracks) {
898 failed=1;
899 continue;
900 }
901
902 Double_t determinant = sumWi.Determinant();
903 //cerr<<" determinant: "<<determinant<<endl;
904 if(determinant < 100.) {
905 printf("det(V) = 0\n");
906 failed=1;
907 continue;
908 }
909
910 // inverted of weights matrix
911 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
912 vV = invsumWi;
913
914 // position of primary vertex
915 rv.Mult(vV,sumWiri);
916
917 } // end loop on the 2 steps
918
919 delete t;
920
921 if(failed) {
922 printf("TooFewTracks\n");
923 fCurrentVertex = new AliESDVertex(0.,0.,-1);
924 return;
925 }
926
927 Double_t position[3];
928 position[0] = rv(0,0);
929 position[1] = rv(1,0);
930 position[2] = rv(2,0);
931 Double_t covmatrix[6];
932 covmatrix[0] = vV(0,0);
933 covmatrix[1] = vV(0,1);
934 covmatrix[2] = vV(1,1);
935 covmatrix[3] = vV(0,2);
936 covmatrix[4] = vV(1,2);
937 covmatrix[5] = vV(2,2);
938
939 // store data in the vertex object
940 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nUsedTrks);
941
942 if(fDebug) {
943 printf(" VertexFitter(): finish\n");
944 printf(" rv = ( %f , %f , %f )\n\n",rv(0,0),rv(1,0),rv(2,0));
945 fCurrentVertex->PrintStatus();
946 }
947
948 return;
949}
950//---------------------------------------------------------------------------
951void AliVertexerTracks::TooFewTracks(const AliESD* esdEvent) {
952//
953// When the number of tracks is < fMinTracks
954//
955
956 // deal with vertices not found
957 Double_t pos[3],err[3];
958 Int_t ncontr=0;
959 pos[0] = fNominalPos[0];
960 err[0] = fNominalSigma[0];
961 pos[1] = fNominalPos[1];
962 err[1] = fNominalSigma[1];
963 pos[2] = esdEvent->GetVertex()->GetZv();
964 err[2] = esdEvent->GetVertex()->GetZRes();
965 if(err[0]>1. && esdEvent->GetVertex()->GetNContributors()<=0)
966 ncontr = -1; // (x,y,z) = (0,0,0)
967 if(err[0]>1. && esdEvent->GetVertex()->GetNContributors()>0)
968 ncontr = -2; // (x,y,z) = (0,0,z_fromSPD)
969 if(err[0]<1. && esdEvent->GetVertex()->GetNContributors()<=0)
970 ncontr = -3; // (x,y,z) = (x_mean,y_mean,0)
971 if(err[0]<1. && esdEvent->GetVertex()->GetNContributors()>0)
972 ncontr = -4; // (x,y,z) = (x_mean,y_mean,z_fromSPD)
973 fCurrentVertex = 0;
974 fCurrentVertex = new AliESDVertex(pos,err);
975 fCurrentVertex->SetNContributors(ncontr);
976
977 Double_t tp[3];
978 esdEvent->GetVertex()->GetTruePos(tp);
979 fCurrentVertex->SetTruePos(tp);
980 fCurrentVertex->SetTitle("VertexerTracksWithConstraint");
981 if(ncontr==-1||ncontr==-2)
982 fCurrentVertex->SetTitle("VertexerTracksNoConstraint");
983
984 return;
985}