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[u/mrichter/AliRoot.git] / STEER / AliVertexerTracks.cxx
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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),
fee9ef0d 45fConstraint(kFALSE),
46fOnlyFitter(kFALSE),
0c69be49 47fMinTracks(1),
fe12e09c 48fMinITSClusters(5),
07680cae 49fTrkArray(),
50fTrksToSkip(0),
51fNTrksToSkip(0),
52fDCAcut(0),
53fAlgo(1),
fe12e09c 54fNSigma(3),
fee9ef0d 55fMaxd0z0(0.5),
50ff0bcd 56fITSin(kTRUE),
57fITSrefit(kTRUE),
07680cae 58fDebug(0)
2d57349e 59{
60//
61// Default constructor
62//
63 SetVtxStart();
07680cae 64 SetVtxStartSigma();
2d57349e 65 SetMinTracks();
07680cae 66 SetMinITSClusters();
67 SetNSigmad0();
fee9ef0d 68 SetMaxd0z0();
2d57349e 69}
70//-----------------------------------------------------------------------------
71AliVertexerTracks::AliVertexerTracks(Double_t xStart, Double_t yStart):
07680cae 72TObject(),
73fVert(),
74fCurrentVertex(0),
fee9ef0d 75fConstraint(kFALSE),
76fOnlyFitter(kFALSE),
0c69be49 77fMinTracks(1),
fe12e09c 78fMinITSClusters(5),
07680cae 79fTrkArray(),
80fTrksToSkip(0),
81fNTrksToSkip(0),
82fDCAcut(0),
83fAlgo(1),
fe12e09c 84fNSigma(3),
fee9ef0d 85fMaxd0z0(0.5),
50ff0bcd 86fITSin(kTRUE),
87fITSrefit(kTRUE),
07680cae 88fDebug(0)
2d57349e 89{
90//
91// Standard constructor
92//
93 SetVtxStart(xStart,yStart);
07680cae 94 SetVtxStartSigma();
2d57349e 95 SetMinTracks();
07680cae 96 SetMinITSClusters();
97 SetNSigmad0();
fee9ef0d 98 SetMaxd0z0();
2d57349e 99}
100//-----------------------------------------------------------------------------
fee9ef0d 101AliVertexerTracks::~AliVertexerTracks()
102{
2d57349e 103 // Default Destructor
eae1677e 104 // The objects pointed by the following pointer are not owned
2d57349e 105 // by this class and are not deleted
ec1be5d5 106 fCurrentVertex = 0;
07680cae 107 delete[] fTrksToSkip;
ec1be5d5 108}
c5e3e5d1 109//----------------------------------------------------------------------------
ec1be5d5 110AliESDVertex* AliVertexerTracks::FindPrimaryVertex(const AliESD *esdEvent)
111{
c5e3e5d1 112//
ec1be5d5 113// Primary vertex for current ESD event
eae1677e 114// (Two iterations:
fee9ef0d 115// 1st with 5*fNSigma*sigma cut w.r.t. to initial vertex
116// + cut on sqrt(d0d0+z0z0) if fConstraint=kFALSE
117// 2nd with fNSigma*sigma cut w.r.t. to vertex found in 1st iteration)
318aecb9 118// All ESD tracks with inside the beam pipe are then propagated to found vertex
07680cae 119//
120 fCurrentVertex = 0;
121
fee9ef0d 122 // read tracks from ESD
50ff0bcd 123 Int_t nTrksTot = (Int_t)esdEvent->GetNumberOfTracks();
07680cae 124 TTree *trkTree = new TTree("TreeT","tracks");
125 AliESDtrack *esdTrack = 0;
126 trkTree->Branch("tracks","AliESDtrack",&esdTrack);
127
eae1677e 128 Bool_t skipThis;
50ff0bcd 129 for(Int_t i=0; i<nTrksTot; i++) {
fee9ef0d 130 AliESDtrack *et = esdEvent->GetTrack(i);
131 esdTrack = new AliESDtrack(*et);
eae1677e 132 // check tracks to skip
133 skipThis = kFALSE;
134 for(Int_t j=0; j<fNTrksToSkip; j++) {
fee9ef0d 135 if(et->GetID()==fTrksToSkip[j]) {
eae1677e 136 if(fDebug) printf("skipping track: %d\n",i);
137 skipThis = kTRUE;
138 }
139 }
50ff0bcd 140 if(skipThis) {delete esdTrack;continue;}
141 if(fITSin) {
142 if(!(esdTrack->GetStatus()&AliESDtrack::kITSin)) {delete esdTrack;continue;}
143 if(fITSrefit && !(esdTrack->GetStatus()&AliESDtrack::kITSrefit)) {delete esdTrack;continue;}
144 Int_t nclus=esdTrack->GetNcls(0); // check number of clusters in ITS
145 if(nclus<fMinITSClusters) {delete esdTrack;continue;}
146 }
07680cae 147 trkTree->Fill();
5834e9a1 148 delete esdTrack;
07680cae 149 }
fee9ef0d 150
151 // If fConstraint=kFALSE
152 // run VertexFinder(1) to get rough estimate of initVertex (x,y)
153 if(!fConstraint) {
154 // fill fTrkArray, for VertexFinder()
155 if(!fTrkArray.IsEmpty()) fTrkArray.Delete();
156 PrepareTracks(*trkTree,0);
157 Double_t cutsave = fDCAcut; fDCAcut = 0.1; // 1 mm
158 VertexFinder(1); // using weights, cutting dca < fDCAcut
159 fDCAcut = cutsave;
5834e9a1 160 fTrkArray.Delete();
fee9ef0d 161 if(fVert.GetNContributors()>0) {
162 fVert.GetXYZ(fNominalPos);
163 fNominalPos[0] = fVert.GetXv();
164 fNominalPos[1] = fVert.GetYv();
165 fNominalPos[2] = fVert.GetZv();
166 if(fDebug) printf("No mean vertex: VertexFinder gives (%f, %f, %f)\n",fNominalPos[0],fNominalPos[1],fNominalPos[2]);
167 } else {
168 fNominalPos[0] = 0.;
169 fNominalPos[1] = 0.;
170 fNominalPos[2] = 0.;
171 if(fDebug) printf("No mean vertex and VertexFinder failed\n");
0c69be49 172 }
07680cae 173 }
fee9ef0d 174
175 // TWO ITERATIONS:
176 //
177 // ITERATION 1
178 // propagate tracks to fNominalPos vertex
179 // preselect them:
180 // if(constraint) reject for |d0|>5*fNSigma*sigma w.r.t. fNominal... vertex
181 // else reject for |d0|\oplus|z0| > 5 mm w.r.t. fNominal... vertex
07680cae 182 // ITERATION 2
183 // propagate tracks to best between initVertex and fCurrentVertex
184 // preselect tracks (reject for |d0|>fNSigma*sigma w.r.t. best
185 // between initVertex and fCurrentVertex)
fee9ef0d 186 for(Int_t iter=0; iter<2; iter++) {
187 if(fOnlyFitter && iter==0) continue;
188 Int_t nTrksPrep = PrepareTracks(*trkTree,iter+1);
189 if(fDebug) printf(" tracks prepared - iteration %d: %d\n",iter+1,nTrksPrep);
190 if(nTrksPrep < fMinTracks) {
191 if(fDebug) printf("TooFewTracks\n");
192 TooFewTracks(esdEvent);
193 if(fDebug) fCurrentVertex->PrintStatus();
194 fTrkArray.Delete();
195 delete trkTree;
196 return fCurrentVertex;
197 }
07680cae 198
fee9ef0d 199 // vertex finder
200 if(!fOnlyFitter) {
201 if(nTrksPrep==1){
202 if(fDebug) printf("Just one track\n");
203 OneTrackVertFinder();
204 }else{
205 switch (fAlgo) {
206 case 1: StrLinVertexFinderMinDist(1); break;
207 case 2: StrLinVertexFinderMinDist(0); break;
208 case 3: HelixVertexFinder(); break;
209 case 4: VertexFinder(1); break;
210 case 5: VertexFinder(0); break;
211 default: printf("Wrong algorithm\n"); break;
212 }
213 }
214 if(fDebug) printf(" Vertex finding completed\n");
0c69be49 215 }
07680cae 216
fee9ef0d 217 // vertex fitter
218 VertexFitter(fConstraint);
219 if(fDebug) printf(" Vertex fit completed\n");
220 if(iter==0) fTrkArray.Delete();
221 } // end loop on the two iterations
07680cae 222
eae1677e 223
fee9ef0d 224 // take true pos from SPD vertex in ESD and write it in tracks' vertex
07680cae 225 Double_t tp[3];
226 esdEvent->GetVertex()->GetTruePos(tp);
227 fCurrentVertex->SetTruePos(tp);
eae1677e 228
fee9ef0d 229 if(fConstraint) {
230 if(fOnlyFitter) {
231 fCurrentVertex->SetTitle("VertexerTracksWithConstraintOnlyFitter");
232 } else {
233 fCurrentVertex->SetTitle("VertexerTracksWithConstraint");
318aecb9 234 }
235 } else {
fee9ef0d 236 fCurrentVertex->SetTitle("VertexerTracksNoConstraint");
318aecb9 237 }
50ff0bcd 238
fee9ef0d 239
50ff0bcd 240 // set indices of used tracks
241 UShort_t *indices = 0;
242 AliESDtrack *ett = 0;
243 if(fCurrentVertex->GetNContributors()>0) {
244 indices = new UShort_t[fCurrentVertex->GetNContributors()];
245 for(Int_t jj=0;jj<(Int_t)fTrkArray.GetEntriesFast();jj++) {
246 ett = (AliESDtrack*)fTrkArray.At(jj);
247 indices[jj] = (UShort_t)ett->GetID();
248 }
249 fCurrentVertex->SetIndices(fCurrentVertex->GetNContributors(),indices);
250 }
251 delete [] indices;
fee9ef0d 252
253 delete trkTree;
254
50ff0bcd 255 fTrkArray.Delete();
256
257 if(fTrksToSkip) delete [] fTrksToSkip;
258
259
260 if(fDebug) fCurrentVertex->PrintStatus();
261 if(fDebug) fCurrentVertex->PrintIndices();
fee9ef0d 262
263
07680cae 264 return fCurrentVertex;
265}
50ff0bcd 266//------------------------------------------------------------------------
fee9ef0d 267Double_t AliVertexerTracks::GetDeterminant3X3(Double_t matr[][3])
268{
50ff0bcd 269 //
270 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];
271 return det;
272}
273//-------------------------------------------------------------------------
fee9ef0d 274void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t (*m)[3],Double_t *d)
275{
50ff0bcd 276 //
277 Double_t x12=p0[0]-p1[0];
278 Double_t y12=p0[1]-p1[1];
279 Double_t z12=p0[2]-p1[2];
280 Double_t kk=x12*x12+y12*y12+z12*z12;
281 m[0][0]=2-2/kk*x12*x12;
282 m[0][1]=-2/kk*x12*y12;
283 m[0][2]=-2/kk*x12*z12;
284 m[1][0]=-2/kk*x12*y12;
285 m[1][1]=2-2/kk*y12*y12;
286 m[1][2]=-2/kk*y12*z12;
287 m[2][0]=-2/kk*x12*z12;
288 m[2][1]=-2*y12*z12;
289 m[2][2]=2-2/kk*z12*z12;
290 d[0]=2*p0[0]-2/kk*p0[0]*x12*x12-2/kk*p0[2]*x12*z12-2/kk*p0[1]*x12*y12;
291 d[1]=2*p0[1]-2/kk*p0[1]*y12*y12-2/kk*p0[0]*x12*y12-2/kk*p0[2]*z12*y12;
292 d[2]=2*p0[2]-2/kk*p0[2]*z12*z12-2/kk*p0[0]*x12*z12-2/kk*p0[1]*z12*y12;
c5e3e5d1 293
50ff0bcd 294}
295//--------------------------------------------------------------------------
fee9ef0d 296void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t *sigmasq,Double_t (*m)[3],Double_t *d)
297{
50ff0bcd 298 //
299 Double_t x12=p1[0]-p0[0];
300 Double_t y12=p1[1]-p0[1];
301 Double_t z12=p1[2]-p0[2];
c5e3e5d1 302
50ff0bcd 303 Double_t den= x12*x12*sigmasq[1]*sigmasq[2]+y12*y12*sigmasq[0]*sigmasq[2]+z12*z12*sigmasq[0]*sigmasq[1];
c5e3e5d1 304
50ff0bcd 305 Double_t kk= 2*(x12*x12/sigmasq[0]+y12*y12/sigmasq[1]+z12*z12/sigmasq[2]);
c5e3e5d1 306
50ff0bcd 307 Double_t cc[3];
308 cc[0]=-x12/sigmasq[0];
309 cc[1]=-y12/sigmasq[1];
310 cc[2]=-z12/sigmasq[2];
ec1be5d5 311
50ff0bcd 312 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;
ec1be5d5 313
50ff0bcd 314 Double_t ss= -p0[0]*cc[0]-p0[1]*cc[1]-p0[2]*cc[2];
2d57349e 315
50ff0bcd 316 Double_t aa[3];
317 aa[0]=x12*sigmasq[1]*sigmasq[2]/den;
318 aa[1]=y12*sigmasq[0]*sigmasq[2]/den;
319 aa[2]=z12*sigmasq[0]*sigmasq[1]/den;
2d57349e 320
50ff0bcd 321 m[0][0]=aa[0]*(aa[0]*kk+2*cc[0])+2*cc[0]*aa[0]+2/sigmasq[0];
322 m[0][1]=aa[1]*(aa[0]*kk+2*cc[0])+2*cc[1]*aa[0];
323 m[0][2]=aa[2]*(aa[0]*kk+2*cc[0])+2*cc[2]*aa[0];
2d57349e 324
50ff0bcd 325 m[1][0]=aa[0]*(aa[1]*kk+2*cc[1])+2*cc[0]*aa[1];
326 m[1][1]=aa[1]*(aa[1]*kk+2*cc[1])+2*cc[1]*aa[1]+2/sigmasq[1];
327 m[1][2]=aa[2]*(aa[1]*kk+2*cc[1])+2*cc[2]*aa[1];
2d57349e 328
50ff0bcd 329 m[2][0]=aa[0]*(aa[2]*kk+2*cc[2])+2*cc[0]*aa[2];
330 m[2][1]=aa[1]*(aa[2]*kk+2*cc[2])+2*cc[1]*aa[2];
331 m[2][2]=aa[2]*(aa[2]*kk+2*cc[2])+2*cc[2]*aa[2]+2/sigmasq[2];
08df6187 332
50ff0bcd 333 d[0]=-ww*(aa[0]*kk+2*cc[0])-2*ss*aa[0]+2*p0[0]/sigmasq[0];
334 d[1]=-ww*(aa[1]*kk+2*cc[1])-2*ss*aa[1]+2*p0[1]/sigmasq[1];
335 d[2]=-ww*(aa[2]*kk+2*cc[2])-2*ss*aa[2]+2*p0[2]/sigmasq[2];
2d57349e 336
2d57349e 337 }
50ff0bcd 338//--------------------------------------------------------------------------
fee9ef0d 339Double_t AliVertexerTracks::GetStrLinMinDist(Double_t *p0,Double_t *p1,Double_t *x0)
340{
50ff0bcd 341 //
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 x10=p0[0]-x0[0];
346 Double_t y10=p0[1]-x0[1];
347 Double_t z10=p0[2]-x0[2];
348 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);
2d57349e 349}
350//---------------------------------------------------------------------------
fee9ef0d 351void AliVertexerTracks::OneTrackVertFinder()
352{
0c69be49 353 // find vertex for events with 1 track, using DCA to nominal beam axis
354 if(fDebug) printf("Number of prepared tracks =%d - Call OneTrackVertFinder",fTrkArray.GetEntries());
355 AliESDtrack *track1;
356 track1 = (AliESDtrack*)fTrkArray.At(0);
357 Double_t field=GetField();
358 Double_t alpha=track1->GetAlpha();
359 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
360 Double_t pos[3],dir[3];
361 track1->GetXYZAt(mindist,field,pos);
362 track1->GetPxPyPzAt(mindist,field,dir);
363 AliStrLine *line1 = new AliStrLine(pos,dir);
364 Double_t p1[3]={fNominalPos[0],fNominalPos[1],0.};
365 Double_t p2[3]={fNominalPos[0],fNominalPos[1],10.};
366 AliStrLine *zeta=new AliStrLine(p1,p2,kTRUE);
367 Double_t crosspoint[3]={0.,0.,0.};
368 Double_t sigma=999.;
369 Int_t nContrib=-1;
370 Int_t retcode = zeta->Cross(line1,crosspoint);
371 if(retcode>=0){
372 sigma=line1->GetDistFromPoint(crosspoint);
373 nContrib=1;
374 }
375 delete zeta;
376 delete line1;
377 fVert.SetXYZ(crosspoint);
378 fVert.SetDispersion(sigma);
379 fVert.SetNContributors(nContrib);
380}
381//---------------------------------------------------------------------------
fee9ef0d 382void AliVertexerTracks::HelixVertexFinder()
383{
2d57349e 384 // Get estimate of vertex position in (x,y) from tracks DCA
385
386
387 Double_t initPos[3];
388 initPos[2] = 0.;
389 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
390 Double_t field=GetField();
391
392 Int_t nacc = (Int_t)fTrkArray.GetEntriesFast();
393
394 Double_t aver[3]={0.,0.,0.};
395 Double_t averquad[3]={0.,0.,0.};
396 Double_t sigmaquad[3]={0.,0.,0.};
397 Double_t sigma=0;
398 Int_t ncombi = 0;
399 AliESDtrack *track1;
400 AliESDtrack *track2;
401 Double_t distCA;
402 Double_t x, par[5];
403 Double_t alpha, cs, sn;
404 Double_t crosspoint[3];
405 for(Int_t i=0; i<nacc; i++){
406 track1 = (AliESDtrack*)fTrkArray.At(i);
407
408
409 for(Int_t j=i+1; j<nacc; j++){
410 track2 = (AliESDtrack*)fTrkArray.At(j);
411
412 distCA=track2->PropagateToDCA(track1,field);
2d57349e 413 if(fDCAcut<=0 ||(fDCAcut>0&&distCA<fDCAcut)){
414 track1->GetExternalParameters(x,par);
415 alpha=track1->GetAlpha();
416 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
417 Double_t x1=x*cs - par[0]*sn;
418 Double_t y1=x*sn + par[0]*cs;
419 Double_t z1=par[1];
420 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
421 track2->GetExternalParameters(x,par);
422 alpha=track2->GetAlpha();
423 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
424 Double_t x2=x*cs - par[0]*sn;
425 Double_t y2=x*sn + par[0]*cs;
426 Double_t z2=par[1];
427 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
428 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
429 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
430 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
431 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
432 crosspoint[0]=wx1*x1 + wx2*x2;
433 crosspoint[1]=wy1*y1 + wy2*y2;
434 crosspoint[2]=wz1*z1 + wz2*z2;
435
436 ncombi++;
437 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
438 for(Int_t jj=0;jj<3;jj++)averquad[jj]+=(crosspoint[jj]*crosspoint[jj]);
439 }
440 }
441
442 }
443 if(ncombi>0){
444 for(Int_t jj=0;jj<3;jj++){
445 initPos[jj] = aver[jj]/ncombi;
446 averquad[jj]/=ncombi;
447 sigmaquad[jj]=averquad[jj]-initPos[jj]*initPos[jj];
448 sigma+=sigmaquad[jj];
449 }
450 sigma=TMath::Sqrt(TMath::Abs(sigma));
451 }
452 else {
453 Warning("HelixVertexFinder","Finder did not succed");
454 sigma=999;
455 }
456 fVert.SetXYZ(initPos);
457 fVert.SetDispersion(sigma);
458 fVert.SetNContributors(ncombi);
459}
50ff0bcd 460//----------------------------------------------------------------------------
fee9ef0d 461Int_t AliVertexerTracks::PrepareTracks(TTree &trkTree,Int_t optImpParCut)
462{
50ff0bcd 463//
464// Propagate tracks to initial vertex position and store them in a TObjArray
465//
fee9ef0d 466 Double_t maxd0rphi;
467 Double_t maxd0z0 = fMaxd0z0; // default is 5 mm
50ff0bcd 468 Int_t nTrks = 0;
469 Double_t sigmaCurr[3];
fee9ef0d 470 Double_t normdistx,normdisty;
50ff0bcd 471 Float_t d0z0[2],covd0z0[3];
472 Double_t sigma;
473 Double_t field=GetField();
474
475 AliESDVertex *initVertex = new AliESDVertex(fNominalPos,fNominalCov,1,1);
476
477 Int_t nEntries = (Int_t)trkTree.GetEntries();
478 if(!fTrkArray.IsEmpty()) fTrkArray.Delete();
479
480 if(fDebug) {
481 printf(" PrepareTracks()\n");
482 }
483
484 for(Int_t i=0; i<nEntries; i++) {
485 AliESDtrack *track = new AliESDtrack;
486 trkTree.SetBranchAddress("tracks",&track);
487 trkTree.GetEvent(i);
488
489 // propagate track to vertex
fee9ef0d 490 if(optImpParCut<=1 || fOnlyFitter) { // optImpParCut==1 or 0
50ff0bcd 491 track->RelateToVertex(initVertex,field,100.);
fee9ef0d 492 } else { // optImpParCut==2
50ff0bcd 493 fCurrentVertex->GetSigmaXYZ(sigmaCurr);
fee9ef0d 494 normdistx = TMath::Abs(fCurrentVertex->GetXv()-fNominalPos[0])/TMath::Sqrt(sigmaCurr[0]*sigmaCurr[0]+fNominalCov[0]);
495 normdisty = TMath::Abs(fCurrentVertex->GetYv()-fNominalPos[1])/TMath::Sqrt(sigmaCurr[1]*sigmaCurr[1]+fNominalCov[1]);
496 if(normdistx < 3. && normdisty < 3. &&
497 (sigmaCurr[0]+sigmaCurr[1])<(TMath::Sqrt(fNominalCov[0])+TMath::Sqrt(fNominalCov[1]))) {
50ff0bcd 498 track->RelateToVertex(fCurrentVertex,field,100.);
499 } else {
500 track->RelateToVertex(initVertex,field,100.);
501 }
502 }
503
50ff0bcd 504 track->GetImpactParameters(d0z0,covd0z0);
505 sigma = TMath::Sqrt(covd0z0[0]);
506 maxd0rphi = fNSigma*sigma;
fee9ef0d 507 if(optImpParCut==1) maxd0rphi *= 5.;
508
509
50ff0bcd 510
fee9ef0d 511 if(fDebug) printf("trk %d; lab %d; |d0| = %f; d0 cut = %f; |z0| = %f; |d0|oplus|z0| = %f; d0z0 cut = %f\n",i,track->GetLabel(),TMath::Abs(d0z0[0]),maxd0rphi,TMath::Abs(d0z0[1]),TMath::Sqrt(d0z0[0]*d0z0[0]+d0z0[1]*d0z0[1]),maxd0z0);
512
513 // during iteration 1, if fConstraint=kFALSE,
514 // select tracks with d0oplusz0 < maxd0z0
515 if(optImpParCut==1 && !fConstraint && nEntries>=3 &&
516 fVert.GetNContributors()>0) {
517 if(TMath::Sqrt(d0z0[0]*d0z0[0]+d0z0[1]*d0z0[1]) > maxd0z0) {
518 if(fDebug) printf(" rejected\n");
519 delete track; continue;
520 }
521 }
522
523 // select tracks with d0rphi < maxd0rphi
524 if(optImpParCut>0 && TMath::Abs(d0z0[0]) > maxd0rphi) {
50ff0bcd 525 if(fDebug) printf(" rejected\n");
526 delete track; continue;
527 }
528
529 fTrkArray.AddLast(track);
530 nTrks++;
531 }
532
533 delete initVertex;
534
535 return nTrks;
536}
537//---------------------------------------------------------------------------
fee9ef0d 538AliESDVertex* AliVertexerTracks::RemoveTracksFromVertex(AliESDVertex *inVtx,
539 TTree *trksTree,
540 Float_t *diamondxy)
541{
50ff0bcd 542//
fee9ef0d 543// Removes tracks in trksTree from fit of inVtx
50ff0bcd 544//
fee9ef0d 545
546 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraintOnlyFitter"))
547 printf("WARNING: result of tracks' removal will be only approximately correct\n");
548
549 TMatrixD rv(3,1);
550 rv(0,0) = inVtx->GetXv();
551 rv(1,0) = inVtx->GetYv();
552 rv(2,0) = inVtx->GetZv();
553 TMatrixD vV(3,3);
554 Double_t cov[6];
555 inVtx->GetCovMatrix(cov);
556 vV(0,0) = cov[0];
557 vV(0,1) = cov[1]; vV(1,0) = cov[1];
558 vV(1,1) = cov[2];
559 vV(0,2) = cov[3]; vV(2,0) = cov[3];
560 vV(1,2) = cov[4]; vV(2,1) = cov[4];
561 vV(2,2) = cov[5];
562
563 TMatrixD sumWi(TMatrixD::kInverted,vV);
564 TMatrixD sumWiri(sumWi,TMatrixD::kMult,rv);
565
566 Int_t nUsedTrks = inVtx->GetNContributors();
567 Double_t chi2 = inVtx->GetChi2();
568
569 AliESDtrack *track = 0;
570 trksTree->SetBranchAddress("tracks",&track);
571 Int_t ntrks = trksTree->GetEntries();
572 for(Int_t i=0;i<ntrks;i++) {
573 trksTree->GetEvent(i);
574 if(!inVtx->UsesTrack(track->GetID())) {
575 printf("track %d was not used in vertex fit\n",track->GetID());
576 continue;
577 }
578 Double_t alpha = track->GetAlpha();
579 Double_t xl = diamondxy[0]*TMath::Cos(alpha)+diamondxy[1]*TMath::Sin(alpha);
580 track->AliExternalTrackParam::PropagateTo(xl,AliTracker::GetBz());
581 // vector of track global coordinates
582 TMatrixD ri(3,1);
583 // covariance matrix of ri
584 TMatrixD wWi(3,3);
585
586 // get space point from track
587 if(!TrackToPoint(track,ri,wWi)) continue;
588
589 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
590
591 sumWi -= wWi;
592 sumWiri -= wWiri;
593
594 // track chi2
595 TMatrixD deltar = rv; deltar -= ri;
596 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
597 Double_t chi2i = deltar(0,0)*wWideltar(0,0)+
598 deltar(1,0)*wWideltar(1,0)+
599 deltar(2,0)*wWideltar(2,0);
600 // remove from total chi2
601 chi2 -= chi2i;
602
603 nUsedTrks--;
604 if(nUsedTrks<2) {
605 printf("Trying to remove too many tracks!\n");
606 return 0x0;
607 }
608 }
609
610 TMatrixD rvnew(3,1);
611 TMatrixD vVnew(3,3);
612
613 // new inverted of weights matrix
614 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
615 vVnew = invsumWi;
616 // new position of primary vertex
617 rvnew.Mult(vVnew,sumWiri);
618
619 Double_t position[3];
620 position[0] = rvnew(0,0);
621 position[1] = rvnew(1,0);
622 position[2] = rvnew(2,0);
623 cov[0] = vVnew(0,0);
624 cov[1] = vVnew(0,1);
625 cov[2] = vVnew(1,1);
626 cov[3] = vVnew(0,2);
627 cov[4] = vVnew(1,2);
628 cov[5] = vVnew(2,2);
629
630 // store data in the vertex object
631 AliESDVertex *outVtx = new AliESDVertex(position,cov,chi2,nUsedTrks);
632 outVtx->SetTitle(inVtx->GetTitle());
633 Double_t tp[3];
634 inVtx->GetTruePos(tp);
635 outVtx->SetTruePos(tp);
636 UShort_t *inindices = inVtx->GetIndices();
637 UShort_t *outindices = new UShort_t[outVtx->GetNContributors()];
638 Int_t j=0;
639 Bool_t copyindex;
640 for(Int_t k=0; k<inVtx->GetNIndices(); k++) {
641 copyindex=kTRUE;
642 for(Int_t l=0; l<ntrks; l++) {
643 trksTree->GetEvent(l);
644 if(inindices[k]==track->GetID()) copyindex=kFALSE;
645 }
646 if(copyindex) {
647 outindices[j] = inindices[k]; j++;
648 }
649 }
650 outVtx->SetIndices(outVtx->GetNContributors(),outindices);
651 delete [] outindices;
652
653 if(fDebug) {
654 printf("Vertex before removing tracks:\n");
655 inVtx->PrintStatus();
656 inVtx->PrintIndices();
657 printf("Vertex after removing tracks:\n");
658 outVtx->PrintStatus();
659 outVtx->PrintIndices();
660 }
661
662 return outVtx;
663}
664//---------------------------------------------------------------------------
665void AliVertexerTracks::SetSkipTracks(Int_t n,Int_t *skipped)
666{
667//
668// Mark the tracks not to be used in the vertex reconstruction.
669// Tracks are identified by AliESDtrack::GetID()
670//
671 fNTrksToSkip = n; fTrksToSkip = new Int_t[n];
50ff0bcd 672 for(Int_t i=0;i<n;i++) fTrksToSkip[i] = skipped[i];
673 return;
674}
675//---------------------------------------------------------------------------
fee9ef0d 676void AliVertexerTracks::SetVtxStart(AliESDVertex *vtx)
677{
50ff0bcd 678//
679// Set initial vertex knowledge
680//
681 vtx->GetXYZ(fNominalPos);
682 vtx->GetCovMatrix(fNominalCov);
fee9ef0d 683 SetConstraintOn();
50ff0bcd 684 return;
685}
2d57349e 686//---------------------------------------------------------------------------
fee9ef0d 687void AliVertexerTracks::StrLinVertexFinderMinDist(Int_t optUseWeights)
688{
2d57349e 689 // Calculate the point at minimum distance to prepared tracks
690
691 Double_t initPos[3];
692 initPos[2] = 0.;
693 Double_t sigma=0;
694 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
695 const Int_t knacc = (Int_t)fTrkArray.GetEntriesFast();
696 Double_t field=GetField();
697
698 AliESDtrack *track1;
699 Double_t (*vectP0)[3]=new Double_t [knacc][3];
700 Double_t (*vectP1)[3]=new Double_t [knacc][3];
701
702 Double_t sum[3][3];
703 Double_t dsum[3]={0,0,0};
704 for(Int_t i=0;i<3;i++)
705 for(Int_t j=0;j<3;j++)sum[i][j]=0;
706 for(Int_t i=0; i<knacc; i++){
707 track1 = (AliESDtrack*)fTrkArray.At(i);
708 Double_t alpha=track1->GetAlpha();
709 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
ec1be5d5 710 Double_t pos[3],dir[3];
711 track1->GetXYZAt(mindist,field,pos);
712 track1->GetPxPyPzAt(mindist,field,dir);
713 AliStrLine *line1 = new AliStrLine(pos,dir);
714 // AliStrLine *line1 = new AliStrLine();
715 // track1->ApproximateHelixWithLine(mindist,field,line1);
2d57349e 716
717 Double_t p0[3],cd[3];
718 line1->GetP0(p0);
719 line1->GetCd(cd);
720 Double_t p1[3]={p0[0]+cd[0],p0[1]+cd[1],p0[2]+cd[2]};
721 vectP0[i][0]=p0[0];
722 vectP0[i][1]=p0[1];
723 vectP0[i][2]=p0[2];
724 vectP1[i][0]=p1[0];
725 vectP1[i][1]=p1[1];
726 vectP1[i][2]=p1[2];
727
728 Double_t matr[3][3];
729 Double_t dknow[3];
730 if(optUseWeights==0)GetStrLinDerivMatrix(p0,p1,matr,dknow);
731 if(optUseWeights==1){
732 Double_t sigmasq[3];
733 sigmasq[0]=track1->GetSigmaY2();
734 sigmasq[1]=track1->GetSigmaY2();
735 sigmasq[2]=track1->GetSigmaZ2();
736 GetStrLinDerivMatrix(p0,p1,sigmasq,matr,dknow);
737 }
738
739 for(Int_t iii=0;iii<3;iii++){
740 dsum[iii]+=dknow[iii];
741 for(Int_t lj=0;lj<3;lj++) sum[iii][lj]+=matr[iii][lj];
742 }
743 delete line1;
744 }
745
746 Double_t vett[3][3];
747 Double_t det=GetDeterminant3X3(sum);
748
fee9ef0d 749 if(det!=0){
750 for(Int_t zz=0;zz<3;zz++){
751 for(Int_t ww=0;ww<3;ww++){
752 for(Int_t kk=0;kk<3;kk++) vett[ww][kk]=sum[ww][kk];
753 }
754 for(Int_t kk=0;kk<3;kk++) vett[kk][zz]=dsum[kk];
755 initPos[zz]=GetDeterminant3X3(vett)/det;
756 }
757
758
759 for(Int_t i=0; i<knacc; i++){
760 Double_t p0[3]={0,0,0},p1[3]={0,0,0};
761 for(Int_t ii=0;ii<3;ii++){
762 p0[ii]=vectP0[i][ii];
763 p1[ii]=vectP1[i][ii];
764 }
765 sigma+=GetStrLinMinDist(p0,p1,initPos);
766 }
767
768 sigma=TMath::Sqrt(sigma);
769 }else{
50ff0bcd 770 Warning("StrLinVertexFinderMinDist","Finder did not succed");
771 sigma=999;
772 }
773 delete vectP0;
774 delete vectP1;
775 fVert.SetXYZ(initPos);
776 fVert.SetDispersion(sigma);
777 fVert.SetNContributors(knacc);
778}
779//---------------------------------------------------------------------------
fee9ef0d 780Bool_t AliVertexerTracks::TrackToPoint(AliESDtrack *t,
781 TMatrixD &ri,TMatrixD &wWi) const
782{
783//
784// Extract from the AliESDtrack the global coordinates ri and covariance matrix
785// wWi of the space point that it represents (to be used in VertexFitter())
786//
787
788
789 Double_t rotAngle = t->GetAlpha();
790 if(rotAngle<0.) rotAngle += 2.*TMath::Pi();
791 Double_t cosRot = TMath::Cos(rotAngle);
792 Double_t sinRot = TMath::Sin(rotAngle);
793
794 ri(0,0) = t->GetX()*cosRot-t->GetY()*sinRot;
795 ri(1,0) = t->GetX()*sinRot+t->GetY()*cosRot;
796 ri(2,0) = t->GetZ();
797
798 // matrix to go from global (x,y,z) to local (y,z);
799 TMatrixD qQi(2,3);
800 qQi(0,0) = -sinRot;
801 qQi(0,1) = cosRot;
802 qQi(0,2) = 0.;
803 qQi(1,0) = 0.;
804 qQi(1,1) = 0.;
805 qQi(1,2) = 1.;
806
807 // covariance matrix of local (y,z) - inverted
808 TMatrixD uUi(2,2);
809 Double_t cc[15];
810 t->GetExternalCovariance(cc);
811 uUi(0,0) = cc[0];
812 uUi(0,1) = cc[1];
813 uUi(1,0) = cc[1];
814 uUi(1,1) = cc[2];
815 if(uUi.Determinant() <= 0.) return kFALSE;
816 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
817
818 // weights matrix: wWi = qQiT * uUiInv * qQi
819 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
820 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
821 wWi = m;
822
823 return kTRUE;
824}
825//---------------------------------------------------------------------------
826void AliVertexerTracks::TooFewTracks(const AliESD* esdEvent)
827{
50ff0bcd 828//
829// When the number of tracks is < fMinTracks
830//
2d57349e 831
50ff0bcd 832 // deal with vertices not found
833 Double_t pos[3],err[3];
834 Int_t ncontr=0;
835 pos[0] = fNominalPos[0];
836 err[0] = TMath::Sqrt(fNominalCov[0]);
837 pos[1] = fNominalPos[1];
838 err[1] = TMath::Sqrt(fNominalCov[2]);
839 pos[2] = esdEvent->GetVertex()->GetZv();
840 err[2] = esdEvent->GetVertex()->GetZRes();
841 if(err[0]>1. && esdEvent->GetVertex()->GetNContributors()<=0)
842 ncontr = -1; // (x,y,z) = (0,0,0)
843 if(err[0]>1. && esdEvent->GetVertex()->GetNContributors()>0)
844 ncontr = -2; // (x,y,z) = (0,0,z_fromSPD)
845 if(err[0]<1. && esdEvent->GetVertex()->GetNContributors()<=0)
846 ncontr = -3; // (x,y,z) = (x_mean,y_mean,0)
847 if(err[0]<1. && esdEvent->GetVertex()->GetNContributors()>0)
848 ncontr = -4; // (x,y,z) = (x_mean,y_mean,z_fromSPD)
849 fCurrentVertex = 0;
850 fCurrentVertex = new AliESDVertex(pos,err);
851 fCurrentVertex->SetNContributors(ncontr);
2d57349e 852
50ff0bcd 853 Double_t tp[3];
854 esdEvent->GetVertex()->GetTruePos(tp);
855 fCurrentVertex->SetTruePos(tp);
fee9ef0d 856 if(fConstraint) {
857 fCurrentVertex->SetTitle("VertexerTracksWithConstraint");
858 } else {
50ff0bcd 859 fCurrentVertex->SetTitle("VertexerTracksNoConstraint");
fee9ef0d 860 }
2d57349e 861
50ff0bcd 862 return;
863}
864//---------------------------------------------------------------------------
fee9ef0d 865void AliVertexerTracks::VertexFinder(Int_t optUseWeights)
866{
2d57349e 867
50ff0bcd 868 // Get estimate of vertex position in (x,y) from tracks DCA
869
870 Double_t initPos[3];
871 initPos[2] = 0.;
872 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
873 Int_t nacc = (Int_t)fTrkArray.GetEntriesFast();
874 Double_t aver[3]={0.,0.,0.};
875 Double_t aversq[3]={0.,0.,0.};
876 Double_t sigmasq[3]={0.,0.,0.};
877 Double_t sigma=0;
878 Int_t ncombi = 0;
879 AliESDtrack *track1;
880 AliESDtrack *track2;
881 Double_t pos[3],dir[3];
882 Double_t alpha,mindist;
883 Double_t field=GetField();
2d57349e 884
50ff0bcd 885 for(Int_t i=0; i<nacc; i++){
886 track1 = (AliESDtrack*)fTrkArray.At(i);
887 alpha=track1->GetAlpha();
888 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
889 track1->GetXYZAt(mindist,field,pos);
890 track1->GetPxPyPzAt(mindist,field,dir);
891 AliStrLine *line1 = new AliStrLine(pos,dir);
2d57349e 892
50ff0bcd 893 // AliStrLine *line1 = new AliStrLine();
894 // track1->ApproximateHelixWithLine(mindist,field,line1);
895
896 for(Int_t j=i+1; j<nacc; j++){
897 track2 = (AliESDtrack*)fTrkArray.At(j);
898 alpha=track2->GetAlpha();
899 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
900 track2->GetXYZAt(mindist,field,pos);
901 track2->GetPxPyPzAt(mindist,field,dir);
902 AliStrLine *line2 = new AliStrLine(pos,dir);
903 // AliStrLine *line2 = new AliStrLine();
904 // track2->ApproximateHelixWithLine(mindist,field,line2);
905 Double_t distCA=line2->GetDCA(line1);
fee9ef0d 906 //printf("%d %d %f\n",i,j,distCA);
907 if(fDCAcut<=0 || (fDCAcut>0&&distCA<fDCAcut)){
50ff0bcd 908 Double_t pnt1[3],pnt2[3],crosspoint[3];
2d57349e 909
50ff0bcd 910 if(optUseWeights<=0){
911 Int_t retcode = line2->Cross(line1,crosspoint);
912 if(retcode>=0){
913 ncombi++;
914 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
915 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
916 }
917 }
918 if(optUseWeights>0){
919 Int_t retcode = line1->CrossPoints(line2,pnt1,pnt2);
920 if(retcode>=0){
5c03260f 921 Double_t cs, sn;
50ff0bcd 922 alpha=track1->GetAlpha();
923 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
924 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
925 alpha=track2->GetAlpha();
926 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
927 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
928 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
929 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
930 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
931 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
932 crosspoint[0]=wx1*pnt1[0] + wx2*pnt2[0];
933 crosspoint[1]=wy1*pnt1[1] + wy2*pnt2[1];
934 crosspoint[2]=wz1*pnt1[2] + wz2*pnt2[2];
935
936 ncombi++;
937 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
938 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
939 }
940 }
941 }
942 delete line2;
943 }
944 delete line1;
71d84967 945 }
50ff0bcd 946 if(ncombi>0){
947 for(Int_t jj=0;jj<3;jj++){
948 initPos[jj] = aver[jj]/ncombi;
fee9ef0d 949 //printf("%f\n",initPos[jj]);
50ff0bcd 950 aversq[jj]/=ncombi;
951 sigmasq[jj]=aversq[jj]-initPos[jj]*initPos[jj];
952 sigma+=sigmasq[jj];
953 }
954 sigma=TMath::Sqrt(TMath::Abs(sigma));
955 }
956 else {
957 Warning("VertexFinder","Finder did not succed");
958 sigma=999;
959 }
960 fVert.SetXYZ(initPos);
961 fVert.SetDispersion(sigma);
962 fVert.SetNContributors(ncombi);
2d57349e 963}
ec1be5d5 964//---------------------------------------------------------------------------
fee9ef0d 965void AliVertexerTracks::VertexFitter(Bool_t useConstraint)
966{
ec1be5d5 967//
968// The optimal estimate of the vertex position is given by a "weighted
969// average of tracks positions"
fee9ef0d 970// Original method: V. Karimaki, CMS Note 97/0051
ec1be5d5 971//
972 Double_t initPos[3];
973 fVert.GetXYZ(initPos);
fee9ef0d 974 Int_t arrEntries = (Int_t)fTrkArray.GetEntries();
975 if(arrEntries==1) useConstraint=kTRUE;
ec1be5d5 976 if(fDebug) {
977 printf(" VertexFitter(): start\n");
978 printf(" Number of tracks in array: %d\n",(Int_t)fTrkArray.GetEntriesFast());
979 printf(" Minimum # tracks required in fit: %d\n",fMinTracks);
980 printf("Vertex position after finder: %f,%f,%f\n",initPos[0],initPos[1],initPos[2]);
fee9ef0d 981 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]));
ec1be5d5 982 }
983
984 Int_t i,j,k,step=0;
985 TMatrixD rv(3,1);
986 TMatrixD vV(3,3);
987 rv(0,0) = initPos[0];
988 rv(1,0) = initPos[1];
989 rv(2,0) = 0.;
990 Double_t xlStart,alpha;
ec1be5d5 991 Int_t nUsedTrks;
fee9ef0d 992 Double_t chi2,chi2i,chi2b;
ec1be5d5 993 AliESDtrack *t = 0;
994 Int_t failed = 0;
995
50ff0bcd 996 // initial vertex covariance matrix
997 TMatrixD vVb(3,3);
998 vVb(0,0) = fNominalCov[0];
999 vVb(0,1) = fNominalCov[1];
1000 vVb(0,2) = 0.;
1001 vVb(1,0) = fNominalCov[1];
1002 vVb(1,1) = fNominalCov[2];
1003 vVb(1,2) = 0.;
1004 vVb(2,0) = 0.;
1005 vVb(2,1) = 0.;
1006 vVb(2,2) = fNominalCov[5];
1007 TMatrixD vVbInv(TMatrixD::kInverted,vVb);
1008 TMatrixD rb(3,1);
1009 rb(0,0) = fNominalPos[0];
1010 rb(1,0) = fNominalPos[1];
1011 rb(2,0) = fNominalPos[2];
1012 TMatrixD vVbInvrb(vVbInv,TMatrixD::kMult,rb);
1013
1014
eae1677e 1015 // 2 steps:
1016 // 1st - estimate of vtx using all tracks
1017 // 2nd - estimate of global chi2
1018 for(step=0; step<2; step++) {
ec1be5d5 1019 if(fDebug) printf(" step = %d\n",step);
1020 chi2 = 0.;
1021 nUsedTrks = 0;
1022
1023 TMatrixD sumWiri(3,1);
1024 TMatrixD sumWi(3,3);
1025 for(i=0; i<3; i++) {
1026 sumWiri(i,0) = 0.;
1027 for(j=0; j<3; j++) sumWi(j,i) = 0.;
1028 }
1029
fee9ef0d 1030 // mean vertex constraint
1031 if(useConstraint) {
50ff0bcd 1032 for(i=0;i<3;i++) {
1033 sumWiri(i,0) += vVbInvrb(i,0);
1034 for(k=0;k<3;k++) sumWi(i,k) += vVbInv(i,k);
07680cae 1035 }
fee9ef0d 1036 // chi2
1037 TMatrixD deltar = rv; deltar -= rb;
1038 TMatrixD vVbInvdeltar(vVbInv,TMatrixD::kMult,deltar);
1039 chi2b = deltar(0,0)*vVbInvdeltar(0,0)+
1040 deltar(1,0)*vVbInvdeltar(1,0)+
1041 deltar(2,0)*vVbInvdeltar(2,0);
1042 chi2 += chi2b;
07680cae 1043 }
1044
1045
ec1be5d5 1046 // loop on tracks
1047 for(k=0; k<arrEntries; k++) {
ec1be5d5 1048 // get track from track array
1049 t = (AliESDtrack*)fTrkArray.At(k);
1050 alpha = t->GetAlpha();
1051 xlStart = initPos[0]*TMath::Cos(alpha)+initPos[1]*TMath::Sin(alpha);
fee9ef0d 1052 // to vtxSeed (from finder)
1053 t->AliExternalTrackParam::PropagateTo(xlStart,AliTracker::GetBz());
1054
1055
ec1be5d5 1056 // vector of track global coordinates
1057 TMatrixD ri(3,1);
fee9ef0d 1058 // covariance matrix of ri
1059 TMatrixD wWi(3,3);
1060
1061 // get space point from track
1062 if(!TrackToPoint(t,ri,wWi)) continue;
1063
1064 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
ec1be5d5 1065
1066 // track chi2
1067 TMatrixD deltar = rv; deltar -= ri;
1068 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
1069 chi2i = deltar(0,0)*wWideltar(0,0)+
1070 deltar(1,0)*wWideltar(1,0)+
1071 deltar(2,0)*wWideltar(2,0);
1072
ec1be5d5 1073 // add to total chi2
1074 chi2 += chi2i;
1075
ec1be5d5 1076 sumWiri += wWiri;
1077 sumWi += wWi;
1078
1079 nUsedTrks++;
1080 } // end loop on tracks
1081
1082 if(nUsedTrks < fMinTracks) {
1083 failed=1;
1084 continue;
1085 }
1086
1087 Double_t determinant = sumWi.Determinant();
1088 //cerr<<" determinant: "<<determinant<<endl;
1089 if(determinant < 100.) {
1090 printf("det(V) = 0\n");
1091 failed=1;
1092 continue;
1093 }
1094
1095 // inverted of weights matrix
1096 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
1097 vV = invsumWi;
1098
1099 // position of primary vertex
1100 rv.Mult(vV,sumWiri);
1101
eae1677e 1102 } // end loop on the 2 steps
ec1be5d5 1103
5834e9a1 1104 // delete t;
ec1be5d5 1105
1106 if(failed) {
50ff0bcd 1107 if(fDebug) printf("TooFewTracks\n");
ec1be5d5 1108 fCurrentVertex = new AliESDVertex(0.,0.,-1);
1109 return;
1110 }
1111
1112 Double_t position[3];
1113 position[0] = rv(0,0);
1114 position[1] = rv(1,0);
1115 position[2] = rv(2,0);
1116 Double_t covmatrix[6];
1117 covmatrix[0] = vV(0,0);
1118 covmatrix[1] = vV(0,1);
1119 covmatrix[2] = vV(1,1);
1120 covmatrix[3] = vV(0,2);
1121 covmatrix[4] = vV(1,2);
1122 covmatrix[5] = vV(2,2);
1123
1124 // store data in the vertex object
1125 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nUsedTrks);
1126
1127 if(fDebug) {
1128 printf(" VertexFitter(): finish\n");
1129 printf(" rv = ( %f , %f , %f )\n\n",rv(0,0),rv(1,0),rv(2,0));
1130 fCurrentVertex->PrintStatus();
1131 }
1132
1133 return;
1134}
50ff0bcd 1135//----------------------------------------------------------------------------
fee9ef0d 1136AliESDVertex* AliVertexerTracks::VertexForSelectedTracks(TTree *trkTree,Bool_t optUseFitter,Bool_t optPropagate)
1137{
eae1677e 1138//
50ff0bcd 1139// Return vertex from tracks in trkTree
eae1677e 1140//
1141
fee9ef0d 1142 SetConstraintOff();
1143
50ff0bcd 1144 // get tracks and propagate them to initial vertex position
fee9ef0d 1145 Int_t nTrksPrep = PrepareTracks(*trkTree,0);
0c69be49 1146 if(nTrksPrep < TMath::Max(2,fMinTracks) ) {
50ff0bcd 1147 if(fDebug) printf("TooFewTracks\n");
fee9ef0d 1148 fCurrentVertex = new AliESDVertex(0.,0.,-1);
1149 return fCurrentVertex;
50ff0bcd 1150 }
1151
fee9ef0d 1152 switch (fAlgo) {
1153 case 1: StrLinVertexFinderMinDist(1); break;
1154 case 2: StrLinVertexFinderMinDist(0); break;
1155 case 3: HelixVertexFinder(); break;
1156 case 4: VertexFinder(1); break;
1157 case 5: VertexFinder(0); break;
1158 default: printf("Wrong algorithm\n"); break;
1159 }
50ff0bcd 1160
fee9ef0d 1161 if(fDebug) printf(" Vertex finding completed\n");
1162
1163 // vertex fitter
1164 if(optUseFitter){
1165 VertexFitter(fConstraint);
1166 if(fDebug) printf(" Vertex fit completed\n");
1167 }else{
1168 Double_t position[3]={fVert.GetXv(),fVert.GetYv(),fVert.GetZv()};
1169 Double_t covmatrix[6]={0.,0.,0.,0.,0.,0.};
1170 Double_t chi2=99999.;
1171 Int_t nUsedTrks=fVert.GetNContributors();
1172 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nUsedTrks);
1173 }
1174 fCurrentVertex->SetDispersion(fVert.GetDispersion());
1175
1176
1177 // set indices of used tracks and propagate track to found vertex
50ff0bcd 1178 UShort_t *indices = 0;
1179 AliESDtrack *eta = 0;
fee9ef0d 1180 if(fCurrentVertex->GetNContributors()>0) {
1181 indices = new UShort_t[fCurrentVertex->GetNContributors()];
50ff0bcd 1182 for(Int_t jj=0;jj<(Int_t)fTrkArray.GetEntriesFast();jj++) {
1183 eta = (AliESDtrack*)fTrkArray.At(jj);
1184 indices[jj] = (UShort_t)eta->GetID();
fee9ef0d 1185 if(optPropagate&&optUseFitter){
1186 if(TMath::Sqrt(fCurrentVertex->GetXv()*fCurrentVertex->GetXv()+fCurrentVertex->GetYv()*fCurrentVertex->GetYv())<3.) {
1187 eta->RelateToVertex(fCurrentVertex,GetField(),100.);
1188 if(fDebug) printf("Track %d propagated to found vertex\n",jj);
1189 }else{
1190 AliWarning("Found vertex outside beam pipe!");
1191 }
1192 }
50ff0bcd 1193 }
fee9ef0d 1194 fCurrentVertex->SetIndices(fCurrentVertex->GetNContributors(),indices);
50ff0bcd 1195 }
1196 delete [] indices;
1197 fTrkArray.Delete();
1198
fee9ef0d 1199 return fCurrentVertex;
eae1677e 1200}
50ff0bcd 1201//----------------------------------------------------------------------------
fee9ef0d 1202AliESDVertex* AliVertexerTracks::VertexForSelectedTracks(TObjArray *trkArray,Bool_t optUseFitter, Bool_t optPropagate)
1203{
50ff0bcd 1204//
1205// Return vertex from array of tracks
1206//
5834e9a1 1207
50ff0bcd 1208 // get tracks and propagate them to initial vertex position
1209 Int_t nTrks = trkArray->GetEntriesFast();
0c69be49 1210 if(nTrks < TMath::Max(2,fMinTracks) ) {
50ff0bcd 1211 if(fDebug) printf("TooFewTracks\n");
fee9ef0d 1212 fCurrentVertex = new AliESDVertex(0.,0.,-1);
1213 return fCurrentVertex;
50ff0bcd 1214 }
1215 TTree *trkTree = new TTree("TreeT","tracks");
1216 AliESDtrack *esdTrack = 0;
1217 trkTree->Branch("tracks","AliESDtrack",&esdTrack);
1218 for(Int_t i=0; i<nTrks; i++){
1219 esdTrack = (AliESDtrack*)trkArray->At(i);
1220 trkTree->Fill();
1221 }
1222
fee9ef0d 1223 AliESDVertex *vtx = VertexForSelectedTracks(trkTree,optUseFitter,optPropagate);
50ff0bcd 1224 delete trkTree;
1225 return vtx;
1226}
1227//--------------------------------------------------------------------------