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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"
af885e0f 34#include "AliESDEvent.h"
2d57349e 35#include "AliESDtrack.h"
36
37ClassImp(AliVertexerTracks)
38
39
40//----------------------------------------------------------------------------
41AliVertexerTracks::AliVertexerTracks():
07680cae 42TObject(),
43fVert(),
44fCurrentVertex(0),
dc3719f3 45fFieldkG(-999.),
fee9ef0d 46fConstraint(kFALSE),
47fOnlyFitter(kFALSE),
0c69be49 48fMinTracks(1),
fe12e09c 49fMinITSClusters(5),
07680cae 50fTrkArray(),
51fTrksToSkip(0),
52fNTrksToSkip(0),
53fDCAcut(0),
54fAlgo(1),
fe12e09c 55fNSigma(3),
fee9ef0d 56fMaxd0z0(0.5),
50ff0bcd 57fITSin(kTRUE),
58fITSrefit(kTRUE),
3b768a1d 59fnSigmaForUi00(1.5),
07680cae 60fDebug(0)
2d57349e 61{
62//
63// Default constructor
64//
3b768a1d 65 SetVtxStart();
07680cae 66 SetVtxStartSigma();
2d57349e 67 SetMinTracks();
07680cae 68 SetMinITSClusters();
69 SetNSigmad0();
fee9ef0d 70 SetMaxd0z0();
2d57349e 71}
dc3719f3 72//----------------------------------------------------------------------------
73AliVertexerTracks::AliVertexerTracks(Double_t fieldkG):
07680cae 74TObject(),
75fVert(),
76fCurrentVertex(0),
dc3719f3 77fFieldkG(-999.),
fee9ef0d 78fConstraint(kFALSE),
79fOnlyFitter(kFALSE),
0c69be49 80fMinTracks(1),
fe12e09c 81fMinITSClusters(5),
07680cae 82fTrkArray(),
83fTrksToSkip(0),
84fNTrksToSkip(0),
85fDCAcut(0),
86fAlgo(1),
fe12e09c 87fNSigma(3),
fee9ef0d 88fMaxd0z0(0.5),
50ff0bcd 89fITSin(kTRUE),
90fITSrefit(kTRUE),
3b768a1d 91fnSigmaForUi00(1.5),
07680cae 92fDebug(0)
2d57349e 93{
94//
95// Standard constructor
96//
3b768a1d 97 SetVtxStart();
07680cae 98 SetVtxStartSigma();
2d57349e 99 SetMinTracks();
07680cae 100 SetMinITSClusters();
101 SetNSigmad0();
dc3719f3 102 SetMaxd0z0();
103 SetFieldkG(fieldkG);
2d57349e 104}
105//-----------------------------------------------------------------------------
fee9ef0d 106AliVertexerTracks::~AliVertexerTracks()
107{
2d57349e 108 // Default Destructor
eae1677e 109 // The objects pointed by the following pointer are not owned
2d57349e 110 // by this class and are not deleted
ec1be5d5 111 fCurrentVertex = 0;
146c29df 112 if(fTrksToSkip) { delete [] fTrksToSkip; fTrksToSkip=NULL; }
ec1be5d5 113}
c5e3e5d1 114//----------------------------------------------------------------------------
af885e0f 115AliESDVertex* AliVertexerTracks::FindPrimaryVertex(const AliESDEvent *esdEvent)
ec1be5d5 116{
c5e3e5d1 117//
ec1be5d5 118// Primary vertex for current ESD event
eae1677e 119// (Two iterations:
fee9ef0d 120// 1st with 5*fNSigma*sigma cut w.r.t. to initial vertex
121// + cut on sqrt(d0d0+z0z0) if fConstraint=kFALSE
122// 2nd with fNSigma*sigma cut w.r.t. to vertex found in 1st iteration)
318aecb9 123// All ESD tracks with inside the beam pipe are then propagated to found vertex
07680cae 124//
125 fCurrentVertex = 0;
126
dc3719f3 127 // accept 1-track case only if constraint is available
128 if(!fConstraint && fMinTracks==1) fMinTracks=2;
129
fee9ef0d 130 // read tracks from ESD
50ff0bcd 131 Int_t nTrksTot = (Int_t)esdEvent->GetNumberOfTracks();
146c29df 132 if(nTrksTot<=0) {
80d36431 133 if(fDebug) printf("TooFewTracks\n");
134 TooFewTracks(esdEvent);
135 return fCurrentVertex;
136 }
713e5fbf 137
07680cae 138 TTree *trkTree = new TTree("TreeT","tracks");
139 AliESDtrack *esdTrack = 0;
140 trkTree->Branch("tracks","AliESDtrack",&esdTrack);
141
eae1677e 142 Bool_t skipThis;
50ff0bcd 143 for(Int_t i=0; i<nTrksTot; i++) {
fee9ef0d 144 AliESDtrack *et = esdEvent->GetTrack(i);
145 esdTrack = new AliESDtrack(*et);
eae1677e 146 // check tracks to skip
147 skipThis = kFALSE;
148 for(Int_t j=0; j<fNTrksToSkip; j++) {
fee9ef0d 149 if(et->GetID()==fTrksToSkip[j]) {
eae1677e 150 if(fDebug) printf("skipping track: %d\n",i);
151 skipThis = kTRUE;
152 }
153 }
50ff0bcd 154 if(skipThis) {delete esdTrack;continue;}
155 if(fITSin) {
156 if(!(esdTrack->GetStatus()&AliESDtrack::kITSin)) {delete esdTrack;continue;}
157 if(fITSrefit && !(esdTrack->GetStatus()&AliESDtrack::kITSrefit)) {delete esdTrack;continue;}
158 Int_t nclus=esdTrack->GetNcls(0); // check number of clusters in ITS
159 if(nclus<fMinITSClusters) {delete esdTrack;continue;}
160 }
07680cae 161 trkTree->Fill();
5834e9a1 162 delete esdTrack;
07680cae 163 }
fee9ef0d 164
165 // If fConstraint=kFALSE
166 // run VertexFinder(1) to get rough estimate of initVertex (x,y)
167 if(!fConstraint) {
168 // fill fTrkArray, for VertexFinder()
169 if(!fTrkArray.IsEmpty()) fTrkArray.Delete();
170 PrepareTracks(*trkTree,0);
171 Double_t cutsave = fDCAcut; fDCAcut = 0.1; // 1 mm
172 VertexFinder(1); // using weights, cutting dca < fDCAcut
173 fDCAcut = cutsave;
5834e9a1 174 fTrkArray.Delete();
fee9ef0d 175 if(fVert.GetNContributors()>0) {
176 fVert.GetXYZ(fNominalPos);
177 fNominalPos[0] = fVert.GetXv();
178 fNominalPos[1] = fVert.GetYv();
179 fNominalPos[2] = fVert.GetZv();
180 if(fDebug) printf("No mean vertex: VertexFinder gives (%f, %f, %f)\n",fNominalPos[0],fNominalPos[1],fNominalPos[2]);
181 } else {
182 fNominalPos[0] = 0.;
183 fNominalPos[1] = 0.;
184 fNominalPos[2] = 0.;
185 if(fDebug) printf("No mean vertex and VertexFinder failed\n");
0c69be49 186 }
07680cae 187 }
fee9ef0d 188
189 // TWO ITERATIONS:
190 //
191 // ITERATION 1
192 // propagate tracks to fNominalPos vertex
193 // preselect them:
194 // if(constraint) reject for |d0|>5*fNSigma*sigma w.r.t. fNominal... vertex
195 // else reject for |d0|\oplus|z0| > 5 mm w.r.t. fNominal... vertex
07680cae 196 // ITERATION 2
197 // propagate tracks to best between initVertex and fCurrentVertex
198 // preselect tracks (reject for |d0|>fNSigma*sigma w.r.t. best
199 // between initVertex and fCurrentVertex)
fee9ef0d 200 for(Int_t iter=0; iter<2; iter++) {
201 if(fOnlyFitter && iter==0) continue;
202 Int_t nTrksPrep = PrepareTracks(*trkTree,iter+1);
203 if(fDebug) printf(" tracks prepared - iteration %d: %d\n",iter+1,nTrksPrep);
204 if(nTrksPrep < fMinTracks) {
205 if(fDebug) printf("TooFewTracks\n");
206 TooFewTracks(esdEvent);
207 if(fDebug) fCurrentVertex->PrintStatus();
208 fTrkArray.Delete();
209 delete trkTree;
210 return fCurrentVertex;
211 }
07680cae 212
fee9ef0d 213 // vertex finder
214 if(!fOnlyFitter) {
215 if(nTrksPrep==1){
216 if(fDebug) printf("Just one track\n");
217 OneTrackVertFinder();
218 }else{
219 switch (fAlgo) {
220 case 1: StrLinVertexFinderMinDist(1); break;
221 case 2: StrLinVertexFinderMinDist(0); break;
222 case 3: HelixVertexFinder(); break;
223 case 4: VertexFinder(1); break;
224 case 5: VertexFinder(0); break;
225 default: printf("Wrong algorithm\n"); break;
226 }
227 }
228 if(fDebug) printf(" Vertex finding completed\n");
0c69be49 229 }
07680cae 230
fee9ef0d 231 // vertex fitter
232 VertexFitter(fConstraint);
233 if(fDebug) printf(" Vertex fit completed\n");
234 if(iter==0) fTrkArray.Delete();
235 } // end loop on the two iterations
07680cae 236
eae1677e 237
fee9ef0d 238 if(fConstraint) {
239 if(fOnlyFitter) {
240 fCurrentVertex->SetTitle("VertexerTracksWithConstraintOnlyFitter");
241 } else {
242 fCurrentVertex->SetTitle("VertexerTracksWithConstraint");
318aecb9 243 }
244 } else {
fee9ef0d 245 fCurrentVertex->SetTitle("VertexerTracksNoConstraint");
318aecb9 246 }
50ff0bcd 247
fee9ef0d 248
50ff0bcd 249 // set indices of used tracks
250 UShort_t *indices = 0;
251 AliESDtrack *ett = 0;
252 if(fCurrentVertex->GetNContributors()>0) {
253 indices = new UShort_t[fCurrentVertex->GetNContributors()];
254 for(Int_t jj=0;jj<(Int_t)fTrkArray.GetEntriesFast();jj++) {
255 ett = (AliESDtrack*)fTrkArray.At(jj);
256 indices[jj] = (UShort_t)ett->GetID();
257 }
258 fCurrentVertex->SetIndices(fCurrentVertex->GetNContributors(),indices);
259 }
260 delete [] indices;
fee9ef0d 261
262 delete trkTree;
263
50ff0bcd 264 fTrkArray.Delete();
265
146c29df 266 if(fTrksToSkip) { delete [] fTrksToSkip; fTrksToSkip=NULL; }
50ff0bcd 267
268
269 if(fDebug) fCurrentVertex->PrintStatus();
270 if(fDebug) fCurrentVertex->PrintIndices();
fee9ef0d 271
272
07680cae 273 return fCurrentVertex;
274}
50ff0bcd 275//------------------------------------------------------------------------
fee9ef0d 276Double_t AliVertexerTracks::GetDeterminant3X3(Double_t matr[][3])
277{
50ff0bcd 278 //
279 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];
280 return det;
281}
282//-------------------------------------------------------------------------
fee9ef0d 283void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t (*m)[3],Double_t *d)
284{
50ff0bcd 285 //
286 Double_t x12=p0[0]-p1[0];
287 Double_t y12=p0[1]-p1[1];
288 Double_t z12=p0[2]-p1[2];
289 Double_t kk=x12*x12+y12*y12+z12*z12;
290 m[0][0]=2-2/kk*x12*x12;
291 m[0][1]=-2/kk*x12*y12;
292 m[0][2]=-2/kk*x12*z12;
293 m[1][0]=-2/kk*x12*y12;
294 m[1][1]=2-2/kk*y12*y12;
295 m[1][2]=-2/kk*y12*z12;
296 m[2][0]=-2/kk*x12*z12;
297 m[2][1]=-2*y12*z12;
298 m[2][2]=2-2/kk*z12*z12;
299 d[0]=2*p0[0]-2/kk*p0[0]*x12*x12-2/kk*p0[2]*x12*z12-2/kk*p0[1]*x12*y12;
300 d[1]=2*p0[1]-2/kk*p0[1]*y12*y12-2/kk*p0[0]*x12*y12-2/kk*p0[2]*z12*y12;
301 d[2]=2*p0[2]-2/kk*p0[2]*z12*z12-2/kk*p0[0]*x12*z12-2/kk*p0[1]*z12*y12;
c5e3e5d1 302
50ff0bcd 303}
304//--------------------------------------------------------------------------
fee9ef0d 305void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t *sigmasq,Double_t (*m)[3],Double_t *d)
306{
50ff0bcd 307 //
308 Double_t x12=p1[0]-p0[0];
309 Double_t y12=p1[1]-p0[1];
310 Double_t z12=p1[2]-p0[2];
c5e3e5d1 311
50ff0bcd 312 Double_t den= x12*x12*sigmasq[1]*sigmasq[2]+y12*y12*sigmasq[0]*sigmasq[2]+z12*z12*sigmasq[0]*sigmasq[1];
c5e3e5d1 313
50ff0bcd 314 Double_t kk= 2*(x12*x12/sigmasq[0]+y12*y12/sigmasq[1]+z12*z12/sigmasq[2]);
c5e3e5d1 315
50ff0bcd 316 Double_t cc[3];
317 cc[0]=-x12/sigmasq[0];
318 cc[1]=-y12/sigmasq[1];
319 cc[2]=-z12/sigmasq[2];
ec1be5d5 320
50ff0bcd 321 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 322
50ff0bcd 323 Double_t ss= -p0[0]*cc[0]-p0[1]*cc[1]-p0[2]*cc[2];
2d57349e 324
50ff0bcd 325 Double_t aa[3];
326 aa[0]=x12*sigmasq[1]*sigmasq[2]/den;
327 aa[1]=y12*sigmasq[0]*sigmasq[2]/den;
328 aa[2]=z12*sigmasq[0]*sigmasq[1]/den;
2d57349e 329
50ff0bcd 330 m[0][0]=aa[0]*(aa[0]*kk+2*cc[0])+2*cc[0]*aa[0]+2/sigmasq[0];
331 m[0][1]=aa[1]*(aa[0]*kk+2*cc[0])+2*cc[1]*aa[0];
332 m[0][2]=aa[2]*(aa[0]*kk+2*cc[0])+2*cc[2]*aa[0];
2d57349e 333
50ff0bcd 334 m[1][0]=aa[0]*(aa[1]*kk+2*cc[1])+2*cc[0]*aa[1];
335 m[1][1]=aa[1]*(aa[1]*kk+2*cc[1])+2*cc[1]*aa[1]+2/sigmasq[1];
336 m[1][2]=aa[2]*(aa[1]*kk+2*cc[1])+2*cc[2]*aa[1];
2d57349e 337
50ff0bcd 338 m[2][0]=aa[0]*(aa[2]*kk+2*cc[2])+2*cc[0]*aa[2];
339 m[2][1]=aa[1]*(aa[2]*kk+2*cc[2])+2*cc[1]*aa[2];
340 m[2][2]=aa[2]*(aa[2]*kk+2*cc[2])+2*cc[2]*aa[2]+2/sigmasq[2];
08df6187 341
50ff0bcd 342 d[0]=-ww*(aa[0]*kk+2*cc[0])-2*ss*aa[0]+2*p0[0]/sigmasq[0];
343 d[1]=-ww*(aa[1]*kk+2*cc[1])-2*ss*aa[1]+2*p0[1]/sigmasq[1];
344 d[2]=-ww*(aa[2]*kk+2*cc[2])-2*ss*aa[2]+2*p0[2]/sigmasq[2];
2d57349e 345
2d57349e 346 }
50ff0bcd 347//--------------------------------------------------------------------------
fee9ef0d 348Double_t AliVertexerTracks::GetStrLinMinDist(Double_t *p0,Double_t *p1,Double_t *x0)
349{
50ff0bcd 350 //
351 Double_t x12=p0[0]-p1[0];
352 Double_t y12=p0[1]-p1[1];
353 Double_t z12=p0[2]-p1[2];
354 Double_t x10=p0[0]-x0[0];
355 Double_t y10=p0[1]-x0[1];
356 Double_t z10=p0[2]-x0[2];
357 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 358}
359//---------------------------------------------------------------------------
fee9ef0d 360void AliVertexerTracks::OneTrackVertFinder()
361{
0c69be49 362 // find vertex for events with 1 track, using DCA to nominal beam axis
363 if(fDebug) printf("Number of prepared tracks =%d - Call OneTrackVertFinder",fTrkArray.GetEntries());
364 AliESDtrack *track1;
365 track1 = (AliESDtrack*)fTrkArray.At(0);
dc3719f3 366 Double_t field=GetFieldkG();
0c69be49 367 Double_t alpha=track1->GetAlpha();
368 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
369 Double_t pos[3],dir[3];
370 track1->GetXYZAt(mindist,field,pos);
371 track1->GetPxPyPzAt(mindist,field,dir);
372 AliStrLine *line1 = new AliStrLine(pos,dir);
373 Double_t p1[3]={fNominalPos[0],fNominalPos[1],0.};
374 Double_t p2[3]={fNominalPos[0],fNominalPos[1],10.};
375 AliStrLine *zeta=new AliStrLine(p1,p2,kTRUE);
376 Double_t crosspoint[3]={0.,0.,0.};
377 Double_t sigma=999.;
378 Int_t nContrib=-1;
379 Int_t retcode = zeta->Cross(line1,crosspoint);
380 if(retcode>=0){
381 sigma=line1->GetDistFromPoint(crosspoint);
382 nContrib=1;
383 }
384 delete zeta;
385 delete line1;
386 fVert.SetXYZ(crosspoint);
387 fVert.SetDispersion(sigma);
388 fVert.SetNContributors(nContrib);
389}
390//---------------------------------------------------------------------------
fee9ef0d 391void AliVertexerTracks::HelixVertexFinder()
392{
2d57349e 393 // Get estimate of vertex position in (x,y) from tracks DCA
394
395
396 Double_t initPos[3];
397 initPos[2] = 0.;
398 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
dc3719f3 399 Double_t field=GetFieldkG();
2d57349e 400
401 Int_t nacc = (Int_t)fTrkArray.GetEntriesFast();
402
403 Double_t aver[3]={0.,0.,0.};
404 Double_t averquad[3]={0.,0.,0.};
405 Double_t sigmaquad[3]={0.,0.,0.};
406 Double_t sigma=0;
407 Int_t ncombi = 0;
408 AliESDtrack *track1;
409 AliESDtrack *track2;
410 Double_t distCA;
411 Double_t x, par[5];
412 Double_t alpha, cs, sn;
413 Double_t crosspoint[3];
414 for(Int_t i=0; i<nacc; i++){
415 track1 = (AliESDtrack*)fTrkArray.At(i);
416
417
418 for(Int_t j=i+1; j<nacc; j++){
419 track2 = (AliESDtrack*)fTrkArray.At(j);
420
421 distCA=track2->PropagateToDCA(track1,field);
2d57349e 422 if(fDCAcut<=0 ||(fDCAcut>0&&distCA<fDCAcut)){
423 track1->GetExternalParameters(x,par);
424 alpha=track1->GetAlpha();
425 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
426 Double_t x1=x*cs - par[0]*sn;
427 Double_t y1=x*sn + par[0]*cs;
428 Double_t z1=par[1];
429 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
430 track2->GetExternalParameters(x,par);
431 alpha=track2->GetAlpha();
432 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
433 Double_t x2=x*cs - par[0]*sn;
434 Double_t y2=x*sn + par[0]*cs;
435 Double_t z2=par[1];
436 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
437 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
438 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
439 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
440 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
441 crosspoint[0]=wx1*x1 + wx2*x2;
442 crosspoint[1]=wy1*y1 + wy2*y2;
443 crosspoint[2]=wz1*z1 + wz2*z2;
444
445 ncombi++;
446 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
447 for(Int_t jj=0;jj<3;jj++)averquad[jj]+=(crosspoint[jj]*crosspoint[jj]);
448 }
449 }
450
451 }
452 if(ncombi>0){
453 for(Int_t jj=0;jj<3;jj++){
454 initPos[jj] = aver[jj]/ncombi;
455 averquad[jj]/=ncombi;
456 sigmaquad[jj]=averquad[jj]-initPos[jj]*initPos[jj];
457 sigma+=sigmaquad[jj];
458 }
459 sigma=TMath::Sqrt(TMath::Abs(sigma));
460 }
461 else {
462 Warning("HelixVertexFinder","Finder did not succed");
463 sigma=999;
464 }
465 fVert.SetXYZ(initPos);
466 fVert.SetDispersion(sigma);
467 fVert.SetNContributors(ncombi);
468}
50ff0bcd 469//----------------------------------------------------------------------------
fee9ef0d 470Int_t AliVertexerTracks::PrepareTracks(TTree &trkTree,Int_t optImpParCut)
471{
50ff0bcd 472//
473// Propagate tracks to initial vertex position and store them in a TObjArray
474//
fee9ef0d 475 Double_t maxd0rphi;
476 Double_t maxd0z0 = fMaxd0z0; // default is 5 mm
50ff0bcd 477 Int_t nTrks = 0;
478 Double_t sigmaCurr[3];
fee9ef0d 479 Double_t normdistx,normdisty;
50ff0bcd 480 Float_t d0z0[2],covd0z0[3];
481 Double_t sigma;
dc3719f3 482 Double_t field=GetFieldkG();
50ff0bcd 483
484 AliESDVertex *initVertex = new AliESDVertex(fNominalPos,fNominalCov,1,1);
485
486 Int_t nEntries = (Int_t)trkTree.GetEntries();
487 if(!fTrkArray.IsEmpty()) fTrkArray.Delete();
488
489 if(fDebug) {
490 printf(" PrepareTracks()\n");
491 }
492
493 for(Int_t i=0; i<nEntries; i++) {
494 AliESDtrack *track = new AliESDtrack;
495 trkTree.SetBranchAddress("tracks",&track);
496 trkTree.GetEvent(i);
497
498 // propagate track to vertex
fee9ef0d 499 if(optImpParCut<=1 || fOnlyFitter) { // optImpParCut==1 or 0
50ff0bcd 500 track->RelateToVertex(initVertex,field,100.);
fee9ef0d 501 } else { // optImpParCut==2
50ff0bcd 502 fCurrentVertex->GetSigmaXYZ(sigmaCurr);
fee9ef0d 503 normdistx = TMath::Abs(fCurrentVertex->GetXv()-fNominalPos[0])/TMath::Sqrt(sigmaCurr[0]*sigmaCurr[0]+fNominalCov[0]);
80d36431 504 normdisty = TMath::Abs(fCurrentVertex->GetYv()-fNominalPos[1])/TMath::Sqrt(sigmaCurr[1]*sigmaCurr[1]+fNominalCov[2]);
fee9ef0d 505 if(normdistx < 3. && normdisty < 3. &&
80d36431 506 (sigmaCurr[0]+sigmaCurr[1])<(TMath::Sqrt(fNominalCov[0])+TMath::Sqrt(fNominalCov[2]))) {
50ff0bcd 507 track->RelateToVertex(fCurrentVertex,field,100.);
508 } else {
509 track->RelateToVertex(initVertex,field,100.);
510 }
511 }
512
50ff0bcd 513 track->GetImpactParameters(d0z0,covd0z0);
514 sigma = TMath::Sqrt(covd0z0[0]);
515 maxd0rphi = fNSigma*sigma;
fee9ef0d 516 if(optImpParCut==1) maxd0rphi *= 5.;
517
518
50ff0bcd 519
fee9ef0d 520 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);
521
80d36431 522 // during iterations 1 and 2, if fConstraint=kFALSE,
fee9ef0d 523 // select tracks with d0oplusz0 < maxd0z0
80d36431 524 if(optImpParCut>=1 && !fConstraint && nEntries>=3 &&
fee9ef0d 525 fVert.GetNContributors()>0) {
526 if(TMath::Sqrt(d0z0[0]*d0z0[0]+d0z0[1]*d0z0[1]) > maxd0z0) {
527 if(fDebug) printf(" rejected\n");
528 delete track; continue;
529 }
530 }
531
532 // select tracks with d0rphi < maxd0rphi
533 if(optImpParCut>0 && TMath::Abs(d0z0[0]) > maxd0rphi) {
50ff0bcd 534 if(fDebug) printf(" rejected\n");
535 delete track; continue;
536 }
537
538 fTrkArray.AddLast(track);
539 nTrks++;
540 }
541
542 delete initVertex;
543
544 return nTrks;
545}
546//---------------------------------------------------------------------------
fee9ef0d 547AliESDVertex* AliVertexerTracks::RemoveTracksFromVertex(AliESDVertex *inVtx,
548 TTree *trksTree,
549 Float_t *diamondxy)
550{
50ff0bcd 551//
fee9ef0d 552// Removes tracks in trksTree from fit of inVtx
50ff0bcd 553//
fee9ef0d 554
146c29df 555 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraint")) {
556 printf("ERROR: primary vertex has no constraint: cannot remove tracks\n");
557 return 0x0;
558 }
fee9ef0d 559 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraintOnlyFitter"))
560 printf("WARNING: result of tracks' removal will be only approximately correct\n");
561
562 TMatrixD rv(3,1);
563 rv(0,0) = inVtx->GetXv();
564 rv(1,0) = inVtx->GetYv();
565 rv(2,0) = inVtx->GetZv();
566 TMatrixD vV(3,3);
567 Double_t cov[6];
568 inVtx->GetCovMatrix(cov);
569 vV(0,0) = cov[0];
570 vV(0,1) = cov[1]; vV(1,0) = cov[1];
571 vV(1,1) = cov[2];
572 vV(0,2) = cov[3]; vV(2,0) = cov[3];
573 vV(1,2) = cov[4]; vV(2,1) = cov[4];
574 vV(2,2) = cov[5];
575
576 TMatrixD sumWi(TMatrixD::kInverted,vV);
577 TMatrixD sumWiri(sumWi,TMatrixD::kMult,rv);
578
579 Int_t nUsedTrks = inVtx->GetNContributors();
580 Double_t chi2 = inVtx->GetChi2();
581
582 AliESDtrack *track = 0;
583 trksTree->SetBranchAddress("tracks",&track);
584 Int_t ntrks = trksTree->GetEntries();
585 for(Int_t i=0;i<ntrks;i++) {
586 trksTree->GetEvent(i);
587 if(!inVtx->UsesTrack(track->GetID())) {
588 printf("track %d was not used in vertex fit\n",track->GetID());
589 continue;
590 }
591 Double_t alpha = track->GetAlpha();
592 Double_t xl = diamondxy[0]*TMath::Cos(alpha)+diamondxy[1]*TMath::Sin(alpha);
dc3719f3 593 track->AliExternalTrackParam::PropagateTo(xl,GetFieldkG());
fee9ef0d 594 // vector of track global coordinates
595 TMatrixD ri(3,1);
596 // covariance matrix of ri
597 TMatrixD wWi(3,3);
598
599 // get space point from track
600 if(!TrackToPoint(track,ri,wWi)) continue;
601
602 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
603
604 sumWi -= wWi;
605 sumWiri -= wWiri;
606
607 // track chi2
608 TMatrixD deltar = rv; deltar -= ri;
609 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
610 Double_t chi2i = deltar(0,0)*wWideltar(0,0)+
611 deltar(1,0)*wWideltar(1,0)+
612 deltar(2,0)*wWideltar(2,0);
613 // remove from total chi2
614 chi2 -= chi2i;
615
616 nUsedTrks--;
617 if(nUsedTrks<2) {
618 printf("Trying to remove too many tracks!\n");
619 return 0x0;
620 }
621 }
622
623 TMatrixD rvnew(3,1);
624 TMatrixD vVnew(3,3);
625
626 // new inverted of weights matrix
627 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
628 vVnew = invsumWi;
629 // new position of primary vertex
630 rvnew.Mult(vVnew,sumWiri);
631
632 Double_t position[3];
633 position[0] = rvnew(0,0);
634 position[1] = rvnew(1,0);
635 position[2] = rvnew(2,0);
636 cov[0] = vVnew(0,0);
637 cov[1] = vVnew(0,1);
638 cov[2] = vVnew(1,1);
639 cov[3] = vVnew(0,2);
640 cov[4] = vVnew(1,2);
641 cov[5] = vVnew(2,2);
642
643 // store data in the vertex object
644 AliESDVertex *outVtx = new AliESDVertex(position,cov,chi2,nUsedTrks);
645 outVtx->SetTitle(inVtx->GetTitle());
fee9ef0d 646 UShort_t *inindices = inVtx->GetIndices();
647 UShort_t *outindices = new UShort_t[outVtx->GetNContributors()];
648 Int_t j=0;
649 Bool_t copyindex;
650 for(Int_t k=0; k<inVtx->GetNIndices(); k++) {
651 copyindex=kTRUE;
652 for(Int_t l=0; l<ntrks; l++) {
653 trksTree->GetEvent(l);
654 if(inindices[k]==track->GetID()) copyindex=kFALSE;
655 }
656 if(copyindex) {
657 outindices[j] = inindices[k]; j++;
658 }
659 }
660 outVtx->SetIndices(outVtx->GetNContributors(),outindices);
661 delete [] outindices;
662
663 if(fDebug) {
664 printf("Vertex before removing tracks:\n");
665 inVtx->PrintStatus();
666 inVtx->PrintIndices();
667 printf("Vertex after removing tracks:\n");
668 outVtx->PrintStatus();
669 outVtx->PrintIndices();
670 }
671
672 return outVtx;
673}
674//---------------------------------------------------------------------------
675void AliVertexerTracks::SetSkipTracks(Int_t n,Int_t *skipped)
676{
677//
678// Mark the tracks not to be used in the vertex reconstruction.
679// Tracks are identified by AliESDtrack::GetID()
680//
681 fNTrksToSkip = n; fTrksToSkip = new Int_t[n];
50ff0bcd 682 for(Int_t i=0;i<n;i++) fTrksToSkip[i] = skipped[i];
683 return;
684}
685//---------------------------------------------------------------------------
fee9ef0d 686void AliVertexerTracks::SetVtxStart(AliESDVertex *vtx)
687{
50ff0bcd 688//
689// Set initial vertex knowledge
690//
691 vtx->GetXYZ(fNominalPos);
692 vtx->GetCovMatrix(fNominalCov);
fee9ef0d 693 SetConstraintOn();
50ff0bcd 694 return;
695}
2d57349e 696//---------------------------------------------------------------------------
fee9ef0d 697void AliVertexerTracks::StrLinVertexFinderMinDist(Int_t optUseWeights)
dc3719f3 698{
699 AliESDtrack *track1;
700 Double_t field=GetFieldkG();
701 const Int_t knacc = (Int_t)fTrkArray.GetEntriesFast();
702 TClonesArray *linarray = new TClonesArray("AliStrLine",1000);
703 TClonesArray &lines = *linarray;
704 for(Int_t i=0; i<knacc; i++){
705 track1 = (AliESDtrack*)fTrkArray.At(i);
706 Double_t alpha=track1->GetAlpha();
707 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
708 Double_t pos[3],dir[3],sigmasq[3];
709 track1->GetXYZAt(mindist,field,pos);
710 track1->GetPxPyPzAt(mindist,field,dir);
711 sigmasq[0]=TMath::Sin(alpha)*TMath::Sin(alpha)*track1->GetSigmaY2();
712 sigmasq[1]=TMath::Cos(alpha)*TMath::Cos(alpha)*track1->GetSigmaY2();
713 sigmasq[2]=track1->GetSigmaZ2();
146c29df 714 TMatrixD ri(3,1);
715 TMatrixD wWi(3,3);
716 if(!TrackToPoint(track1,ri,wWi)) continue;
717 Double_t wmat[9];
718 Int_t iel=0;
719 for(Int_t ia=0;ia<3;ia++){
720 for(Int_t ib=0;ib<3;ib++){
721 wmat[iel]=wWi(ia,ib);
722 iel++;
723 }
724 }
725 new(lines[i]) AliStrLine(pos,sigmasq,wmat,dir);
dc3719f3 726 }
727 fVert=TrackletVertexFinder(linarray,optUseWeights);
728 linarray->Delete();
729 delete linarray;
730}
731//---------------------------------------------------------------------------
146c29df 732AliESDVertex AliVertexerTracks::TrackletVertexFinder(TClonesArray *lines, Int_t optUseWeights)
fee9ef0d 733{
2d57349e 734 // Calculate the point at minimum distance to prepared tracks
735
dc3719f3 736 const Int_t knacc = (Int_t)lines->GetEntriesFast();
737 Double_t initPos[3]={0.,0.,0.};
2d57349e 738
2d57349e 739 Double_t (*vectP0)[3]=new Double_t [knacc][3];
740 Double_t (*vectP1)[3]=new Double_t [knacc][3];
741
742 Double_t sum[3][3];
743 Double_t dsum[3]={0,0,0};
146c29df 744 TMatrixD sumWi(3,3);
745 for(Int_t i=0;i<3;i++){
746 for(Int_t j=0;j<3;j++){
747 sum[i][j]=0;
748 sumWi(i,j)=0.;
749 }
750 }
751
2d57349e 752 for(Int_t i=0; i<knacc; i++){
dc3719f3 753 AliStrLine* line1 = (AliStrLine*)lines->At(i);
754 Double_t p0[3],cd[3],sigmasq[3];
146c29df 755 Double_t wmat[9];
2d57349e 756 line1->GetP0(p0);
757 line1->GetCd(cd);
dc3719f3 758 line1->GetSigma2P0(sigmasq);
146c29df 759 line1->GetWMatrix(wmat);
760 TMatrixD wWi(3,3);
761 Int_t iel=0;
762 for(Int_t ia=0;ia<3;ia++){
763 for(Int_t ib=0;ib<3;ib++){
764 wWi(ia,ib)=wmat[iel];
765 iel++;
766 }
767 }
768
769 sumWi+=wWi;
770
2d57349e 771 Double_t p1[3]={p0[0]+cd[0],p0[1]+cd[1],p0[2]+cd[2]};
772 vectP0[i][0]=p0[0];
773 vectP0[i][1]=p0[1];
774 vectP0[i][2]=p0[2];
775 vectP1[i][0]=p1[0];
776 vectP1[i][1]=p1[1];
777 vectP1[i][2]=p1[2];
778
779 Double_t matr[3][3];
780 Double_t dknow[3];
781 if(optUseWeights==0)GetStrLinDerivMatrix(p0,p1,matr,dknow);
dc3719f3 782 else GetStrLinDerivMatrix(p0,p1,sigmasq,matr,dknow);
783
2d57349e 784
785 for(Int_t iii=0;iii<3;iii++){
786 dsum[iii]+=dknow[iii];
787 for(Int_t lj=0;lj<3;lj++) sum[iii][lj]+=matr[iii][lj];
788 }
2d57349e 789 }
146c29df 790
791 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
792 Double_t covmatrix[6];
793 covmatrix[0] = invsumWi(0,0);
794 covmatrix[1] = invsumWi(0,1);
795 covmatrix[2] = invsumWi(1,1);
796 covmatrix[3] = invsumWi(0,2);
797 covmatrix[4] = invsumWi(1,2);
798 covmatrix[5] = invsumWi(2,2);
799
2d57349e 800 Double_t vett[3][3];
801 Double_t det=GetDeterminant3X3(sum);
dc3719f3 802 Double_t sigma=0;
2d57349e 803
fee9ef0d 804 if(det!=0){
805 for(Int_t zz=0;zz<3;zz++){
806 for(Int_t ww=0;ww<3;ww++){
807 for(Int_t kk=0;kk<3;kk++) vett[ww][kk]=sum[ww][kk];
808 }
809 for(Int_t kk=0;kk<3;kk++) vett[kk][zz]=dsum[kk];
810 initPos[zz]=GetDeterminant3X3(vett)/det;
811 }
812
813
814 for(Int_t i=0; i<knacc; i++){
815 Double_t p0[3]={0,0,0},p1[3]={0,0,0};
816 for(Int_t ii=0;ii<3;ii++){
817 p0[ii]=vectP0[i][ii];
818 p1[ii]=vectP1[i][ii];
819 }
820 sigma+=GetStrLinMinDist(p0,p1,initPos);
821 }
822
823 sigma=TMath::Sqrt(sigma);
824 }else{
50ff0bcd 825 sigma=999;
826 }
146c29df 827 AliESDVertex theVert(initPos,covmatrix,99999.,knacc);
828 theVert.SetDispersion(sigma);
50ff0bcd 829 delete vectP0;
830 delete vectP1;
dc3719f3 831 return theVert;
50ff0bcd 832}
833//---------------------------------------------------------------------------
fee9ef0d 834Bool_t AliVertexerTracks::TrackToPoint(AliESDtrack *t,
0bf2e2b4 835 TMatrixD &ri,TMatrixD &wWi,
836 Bool_t uUi3by3) const
fee9ef0d 837{
838//
839// Extract from the AliESDtrack the global coordinates ri and covariance matrix
840// wWi of the space point that it represents (to be used in VertexFitter())
841//
842
843
844 Double_t rotAngle = t->GetAlpha();
845 if(rotAngle<0.) rotAngle += 2.*TMath::Pi();
846 Double_t cosRot = TMath::Cos(rotAngle);
847 Double_t sinRot = TMath::Sin(rotAngle);
848
849 ri(0,0) = t->GetX()*cosRot-t->GetY()*sinRot;
850 ri(1,0) = t->GetX()*sinRot+t->GetY()*cosRot;
851 ri(2,0) = t->GetZ();
852
0bf2e2b4 853
854
855 if(!uUi3by3) {
856 // matrix to go from global (x,y,z) to local (y,z);
857 TMatrixD qQi(2,3);
858 qQi(0,0) = -sinRot;
859 qQi(0,1) = cosRot;
860 qQi(0,2) = 0.;
861 qQi(1,0) = 0.;
862 qQi(1,1) = 0.;
863 qQi(1,2) = 1.;
864
865 // covariance matrix of local (y,z) - inverted
866 Double_t cc[15];
867 t->GetExternalCovariance(cc);
868 TMatrixD uUi(2,2);
869 uUi(0,0) = cc[0];
870 uUi(0,1) = cc[1];
871 uUi(1,0) = cc[1];
872 uUi(1,1) = cc[2];
873 //printf(" Ui :\n");
874 //printf(" %f %f\n",uUi(0,0),uUi(0,1));
875 //printf(" %f %f\n",uUi(1,0),uUi(1,1));
876
877 if(uUi.Determinant() <= 0.) return kFALSE;
878 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
879
880 // weights matrix: wWi = qQiT * uUiInv * qQi
881 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
882 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
883 wWi = m;
884 } else {
885 if(fVert.GetNContributors()<1) AliFatal("Vertex from finder is empty");
886 // matrix to go from global (x,y,z) to local (x,y,z);
887 TMatrixD qQi(3,3);
888 qQi(0,0) = cosRot;
889 qQi(0,1) = sinRot;
890 qQi(0,2) = 0.;
891 qQi(1,0) = -sinRot;
892 qQi(1,1) = cosRot;
893 qQi(1,2) = 0.;
894 qQi(2,0) = 0.;
895 qQi(2,1) = 0.;
896 qQi(2,2) = 1.;
897
898 // covariance of fVert along the track
899 Double_t p[3],pt,ptot;
900 t->GetPxPyPz(p);
901 pt = TMath::Sqrt(p[0]*p[0]+p[1]*p[1]);
902 ptot = TMath::Sqrt(pt*pt+p[2]*p[2]);
3b768a1d 903 Double_t cphi = p[0]/pt; //cos(phi)=px/pt
904 Double_t sphi = p[1]/pt; //sin(phi)=py/pt
905 Double_t clambda = pt/ptot; //cos(lambda)=pt/ptot
906 Double_t slambda = p[2]/ptot; //sin(lambda)=pz/ptot
0bf2e2b4 907 Double_t covfVert[6];
908 fVert.GetCovMatrix(covfVert);
909 Double_t covfVertalongt =
3b768a1d 910 covfVert[0]*cphi*cphi*clambda*clambda
911 +covfVert[1]*2.*cphi*sphi*clambda*clambda
912 +covfVert[3]*2.*cphi*clambda*slambda
913 +covfVert[2]*sphi*sphi*clambda*clambda
914 +covfVert[4]*2.*sphi*clambda*slambda
915 +covfVert[5]*slambda*slambda;
0bf2e2b4 916 Double_t cc[15];
917 t->GetExternalCovariance(cc);
918 // covariance matrix of local (x,y,z) - inverted
919 TMatrixD uUi(3,3);
3b768a1d 920 uUi(0,0) = covfVertalongt * fnSigmaForUi00 * fnSigmaForUi00;
0bf2e2b4 921 if(fDebug) printf("=====> sqrtUi00 cm %f\n",TMath::Sqrt(uUi(0,0)));
922 uUi(0,1) = 0.;
923 uUi(0,2) = 0.;
924 uUi(1,0) = 0.;
925 uUi(1,1) = cc[0];
926 uUi(1,2) = cc[1];
927 uUi(2,0) = 0.;
928 uUi(2,1) = cc[1];
929 uUi(2,2) = cc[2];
930 //printf(" Ui :\n");
931 //printf(" %f %f\n",uUi(0,0),uUi(0,1));
932 //printf(" %f %f\n",uUi(1,0),uUi(1,1));
fee9ef0d 933
0bf2e2b4 934 if(uUi.Determinant() <= 0.) return kFALSE;
935 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
936
937 // weights matrix: wWi = qQiT * uUiInv * qQi
938 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
939 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
940 wWi = m;
941 }
942
fee9ef0d 943
944 return kTRUE;
945}
946//---------------------------------------------------------------------------
af885e0f 947void AliVertexerTracks::TooFewTracks(const AliESDEvent* esdEvent)
fee9ef0d 948{
50ff0bcd 949//
950// When the number of tracks is < fMinTracks
951//
2d57349e 952
50ff0bcd 953 // deal with vertices not found
954 Double_t pos[3],err[3];
955 Int_t ncontr=0;
956 pos[0] = fNominalPos[0];
957 err[0] = TMath::Sqrt(fNominalCov[0]);
958 pos[1] = fNominalPos[1];
959 err[1] = TMath::Sqrt(fNominalCov[2]);
960 pos[2] = esdEvent->GetVertex()->GetZv();
961 err[2] = esdEvent->GetVertex()->GetZRes();
962 if(err[0]>1. && esdEvent->GetVertex()->GetNContributors()<=0)
963 ncontr = -1; // (x,y,z) = (0,0,0)
964 if(err[0]>1. && esdEvent->GetVertex()->GetNContributors()>0)
965 ncontr = -2; // (x,y,z) = (0,0,z_fromSPD)
966 if(err[0]<1. && esdEvent->GetVertex()->GetNContributors()<=0)
967 ncontr = -3; // (x,y,z) = (x_mean,y_mean,0)
968 if(err[0]<1. && esdEvent->GetVertex()->GetNContributors()>0)
969 ncontr = -4; // (x,y,z) = (x_mean,y_mean,z_fromSPD)
970 fCurrentVertex = 0;
971 fCurrentVertex = new AliESDVertex(pos,err);
972 fCurrentVertex->SetNContributors(ncontr);
2d57349e 973
fee9ef0d 974 if(fConstraint) {
975 fCurrentVertex->SetTitle("VertexerTracksWithConstraint");
976 } else {
50ff0bcd 977 fCurrentVertex->SetTitle("VertexerTracksNoConstraint");
fee9ef0d 978 }
2d57349e 979
50ff0bcd 980 return;
981}
982//---------------------------------------------------------------------------
fee9ef0d 983void AliVertexerTracks::VertexFinder(Int_t optUseWeights)
984{
2d57349e 985
50ff0bcd 986 // Get estimate of vertex position in (x,y) from tracks DCA
987
988 Double_t initPos[3];
989 initPos[2] = 0.;
990 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
991 Int_t nacc = (Int_t)fTrkArray.GetEntriesFast();
992 Double_t aver[3]={0.,0.,0.};
993 Double_t aversq[3]={0.,0.,0.};
994 Double_t sigmasq[3]={0.,0.,0.};
995 Double_t sigma=0;
996 Int_t ncombi = 0;
997 AliESDtrack *track1;
998 AliESDtrack *track2;
999 Double_t pos[3],dir[3];
1000 Double_t alpha,mindist;
dc3719f3 1001 Double_t field=GetFieldkG();
2d57349e 1002
50ff0bcd 1003 for(Int_t i=0; i<nacc; i++){
1004 track1 = (AliESDtrack*)fTrkArray.At(i);
1005 alpha=track1->GetAlpha();
1006 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1007 track1->GetXYZAt(mindist,field,pos);
1008 track1->GetPxPyPzAt(mindist,field,dir);
1009 AliStrLine *line1 = new AliStrLine(pos,dir);
2d57349e 1010
50ff0bcd 1011 // AliStrLine *line1 = new AliStrLine();
1012 // track1->ApproximateHelixWithLine(mindist,field,line1);
1013
1014 for(Int_t j=i+1; j<nacc; j++){
1015 track2 = (AliESDtrack*)fTrkArray.At(j);
1016 alpha=track2->GetAlpha();
1017 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1018 track2->GetXYZAt(mindist,field,pos);
1019 track2->GetPxPyPzAt(mindist,field,dir);
1020 AliStrLine *line2 = new AliStrLine(pos,dir);
1021 // AliStrLine *line2 = new AliStrLine();
1022 // track2->ApproximateHelixWithLine(mindist,field,line2);
1023 Double_t distCA=line2->GetDCA(line1);
fee9ef0d 1024 //printf("%d %d %f\n",i,j,distCA);
1025 if(fDCAcut<=0 || (fDCAcut>0&&distCA<fDCAcut)){
50ff0bcd 1026 Double_t pnt1[3],pnt2[3],crosspoint[3];
2d57349e 1027
50ff0bcd 1028 if(optUseWeights<=0){
1029 Int_t retcode = line2->Cross(line1,crosspoint);
1030 if(retcode>=0){
1031 ncombi++;
1032 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
1033 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1034 }
1035 }
1036 if(optUseWeights>0){
1037 Int_t retcode = line1->CrossPoints(line2,pnt1,pnt2);
1038 if(retcode>=0){
5c03260f 1039 Double_t cs, sn;
50ff0bcd 1040 alpha=track1->GetAlpha();
1041 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
1042 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
1043 alpha=track2->GetAlpha();
1044 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
1045 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
1046 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
1047 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
1048 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
1049 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
1050 crosspoint[0]=wx1*pnt1[0] + wx2*pnt2[0];
1051 crosspoint[1]=wy1*pnt1[1] + wy2*pnt2[1];
1052 crosspoint[2]=wz1*pnt1[2] + wz2*pnt2[2];
1053
1054 ncombi++;
1055 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
1056 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1057 }
1058 }
1059 }
1060 delete line2;
1061 }
1062 delete line1;
71d84967 1063 }
50ff0bcd 1064 if(ncombi>0){
1065 for(Int_t jj=0;jj<3;jj++){
1066 initPos[jj] = aver[jj]/ncombi;
fee9ef0d 1067 //printf("%f\n",initPos[jj]);
50ff0bcd 1068 aversq[jj]/=ncombi;
1069 sigmasq[jj]=aversq[jj]-initPos[jj]*initPos[jj];
1070 sigma+=sigmasq[jj];
1071 }
1072 sigma=TMath::Sqrt(TMath::Abs(sigma));
1073 }
1074 else {
1075 Warning("VertexFinder","Finder did not succed");
1076 sigma=999;
1077 }
1078 fVert.SetXYZ(initPos);
1079 fVert.SetDispersion(sigma);
1080 fVert.SetNContributors(ncombi);
2d57349e 1081}
ec1be5d5 1082//---------------------------------------------------------------------------
fee9ef0d 1083void AliVertexerTracks::VertexFitter(Bool_t useConstraint)
1084{
ec1be5d5 1085//
1086// The optimal estimate of the vertex position is given by a "weighted
0bf2e2b4 1087// average of tracks positions".
fee9ef0d 1088// Original method: V. Karimaki, CMS Note 97/0051
ec1be5d5 1089//
1090 Double_t initPos[3];
0bf2e2b4 1091 if(!fOnlyFitter) {
1092 fVert.GetXYZ(initPos);
1093 } else {
1094 initPos[0]=fNominalPos[0];
1095 initPos[1]=fNominalPos[1];
1096 initPos[2]=fNominalPos[2];
1097 }
1098
1099 Int_t nTrks = (Int_t)fTrkArray.GetEntries();
1100 if(nTrks==1) useConstraint=kTRUE;
ec1be5d5 1101 if(fDebug) {
0bf2e2b4 1102 printf("--- VertexFitter(): start\n");
1103 printf(" Number of tracks in array: %d\n",nTrks);
ec1be5d5 1104 printf(" Minimum # tracks required in fit: %d\n",fMinTracks);
3b768a1d 1105 printf(" Vertex position after finder: %f,%f,%f\n",initPos[0],initPos[1],initPos[2]);
fee9ef0d 1106 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 1107 }
1108
0bf2e2b4 1109 // special treatment for few-tracks fits (e.g. secondary vertices)
1110 Bool_t uUi3by3 = kFALSE; if(nTrks<5 && !useConstraint) uUi3by3 = kTRUE;
1111
ec1be5d5 1112 Int_t i,j,k,step=0;
1113 TMatrixD rv(3,1);
1114 TMatrixD vV(3,3);
1115 rv(0,0) = initPos[0];
1116 rv(1,0) = initPos[1];
1117 rv(2,0) = 0.;
1118 Double_t xlStart,alpha;
ec1be5d5 1119 Int_t nUsedTrks;
fee9ef0d 1120 Double_t chi2,chi2i,chi2b;
ec1be5d5 1121 AliESDtrack *t = 0;
1122 Int_t failed = 0;
1123
50ff0bcd 1124 // initial vertex covariance matrix
1125 TMatrixD vVb(3,3);
1126 vVb(0,0) = fNominalCov[0];
1127 vVb(0,1) = fNominalCov[1];
1128 vVb(0,2) = 0.;
1129 vVb(1,0) = fNominalCov[1];
1130 vVb(1,1) = fNominalCov[2];
1131 vVb(1,2) = 0.;
1132 vVb(2,0) = 0.;
1133 vVb(2,1) = 0.;
1134 vVb(2,2) = fNominalCov[5];
1135 TMatrixD vVbInv(TMatrixD::kInverted,vVb);
1136 TMatrixD rb(3,1);
1137 rb(0,0) = fNominalPos[0];
1138 rb(1,0) = fNominalPos[1];
1139 rb(2,0) = fNominalPos[2];
1140 TMatrixD vVbInvrb(vVbInv,TMatrixD::kMult,rb);
1141
1142
eae1677e 1143 // 2 steps:
1144 // 1st - estimate of vtx using all tracks
1145 // 2nd - estimate of global chi2
1146 for(step=0; step<2; step++) {
ec1be5d5 1147 if(fDebug) printf(" step = %d\n",step);
1148 chi2 = 0.;
1149 nUsedTrks = 0;
1150
0bf2e2b4 1151 if(step==1) { initPos[0]=rv(0,0); initPos[0]=rv(1,0); }
1152
ec1be5d5 1153 TMatrixD sumWiri(3,1);
1154 TMatrixD sumWi(3,3);
1155 for(i=0; i<3; i++) {
1156 sumWiri(i,0) = 0.;
1157 for(j=0; j<3; j++) sumWi(j,i) = 0.;
1158 }
1159
fee9ef0d 1160 // mean vertex constraint
1161 if(useConstraint) {
50ff0bcd 1162 for(i=0;i<3;i++) {
1163 sumWiri(i,0) += vVbInvrb(i,0);
1164 for(k=0;k<3;k++) sumWi(i,k) += vVbInv(i,k);
07680cae 1165 }
fee9ef0d 1166 // chi2
1167 TMatrixD deltar = rv; deltar -= rb;
1168 TMatrixD vVbInvdeltar(vVbInv,TMatrixD::kMult,deltar);
1169 chi2b = deltar(0,0)*vVbInvdeltar(0,0)+
1170 deltar(1,0)*vVbInvdeltar(1,0)+
1171 deltar(2,0)*vVbInvdeltar(2,0);
1172 chi2 += chi2b;
07680cae 1173 }
1174
ec1be5d5 1175 // loop on tracks
0bf2e2b4 1176 for(k=0; k<nTrks; k++) {
ec1be5d5 1177 // get track from track array
1178 t = (AliESDtrack*)fTrkArray.At(k);
1179 alpha = t->GetAlpha();
1180 xlStart = initPos[0]*TMath::Cos(alpha)+initPos[1]*TMath::Sin(alpha);
fee9ef0d 1181 // to vtxSeed (from finder)
dc3719f3 1182 t->AliExternalTrackParam::PropagateTo(xlStart,GetFieldkG());
fee9ef0d 1183
ec1be5d5 1184 // vector of track global coordinates
1185 TMatrixD ri(3,1);
fee9ef0d 1186 // covariance matrix of ri
1187 TMatrixD wWi(3,3);
1188
1189 // get space point from track
0bf2e2b4 1190 if(!TrackToPoint(t,ri,wWi,uUi3by3)) continue;
fee9ef0d 1191 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
ec1be5d5 1192
1193 // track chi2
1194 TMatrixD deltar = rv; deltar -= ri;
1195 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
1196 chi2i = deltar(0,0)*wWideltar(0,0)+
1197 deltar(1,0)*wWideltar(1,0)+
1198 deltar(2,0)*wWideltar(2,0);
1199
ec1be5d5 1200 // add to total chi2
1201 chi2 += chi2i;
1202
ec1be5d5 1203 sumWiri += wWiri;
1204 sumWi += wWi;
1205
1206 nUsedTrks++;
1207 } // end loop on tracks
1208
1209 if(nUsedTrks < fMinTracks) {
1210 failed=1;
1211 continue;
1212 }
1213
1214 Double_t determinant = sumWi.Determinant();
1215 //cerr<<" determinant: "<<determinant<<endl;
1216 if(determinant < 100.) {
1217 printf("det(V) = 0\n");
1218 failed=1;
1219 continue;
1220 }
1221
0bf2e2b4 1222 if(step==0) {
1223 // inverted of weights matrix
1224 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
1225 vV = invsumWi;
1226 // position of primary vertex
1227 rv.Mult(vV,sumWiri);
1228 }
eae1677e 1229 } // end loop on the 2 steps
ec1be5d5 1230
ec1be5d5 1231 if(failed) {
50ff0bcd 1232 if(fDebug) printf("TooFewTracks\n");
ec1be5d5 1233 fCurrentVertex = new AliESDVertex(0.,0.,-1);
1234 return;
1235 }
1236
1237 Double_t position[3];
1238 position[0] = rv(0,0);
1239 position[1] = rv(1,0);
1240 position[2] = rv(2,0);
1241 Double_t covmatrix[6];
1242 covmatrix[0] = vV(0,0);
1243 covmatrix[1] = vV(0,1);
1244 covmatrix[2] = vV(1,1);
1245 covmatrix[3] = vV(0,2);
1246 covmatrix[4] = vV(1,2);
1247 covmatrix[5] = vV(2,2);
1248
dc3719f3 1249 // for correct chi2/ndf, count constraint as additional "track"
1250 if(fConstraint) nUsedTrks++;
ec1be5d5 1251 // store data in the vertex object
1252 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nUsedTrks);
1253
1254 if(fDebug) {
0bf2e2b4 1255 printf(" Vertex after fit:\n");
ec1be5d5 1256 fCurrentVertex->PrintStatus();
0bf2e2b4 1257 printf("--- VertexFitter(): finish\n");
ec1be5d5 1258 }
1259
1260 return;
1261}
50ff0bcd 1262//----------------------------------------------------------------------------
fee9ef0d 1263AliESDVertex* AliVertexerTracks::VertexForSelectedTracks(TTree *trkTree,Bool_t optUseFitter,Bool_t optPropagate)
1264{
eae1677e 1265//
50ff0bcd 1266// Return vertex from tracks in trkTree
eae1677e 1267//
1268
fee9ef0d 1269 SetConstraintOff();
1270
50ff0bcd 1271 // get tracks and propagate them to initial vertex position
fee9ef0d 1272 Int_t nTrksPrep = PrepareTracks(*trkTree,0);
0c69be49 1273 if(nTrksPrep < TMath::Max(2,fMinTracks) ) {
50ff0bcd 1274 if(fDebug) printf("TooFewTracks\n");
fee9ef0d 1275 fCurrentVertex = new AliESDVertex(0.,0.,-1);
1276 return fCurrentVertex;
50ff0bcd 1277 }
1278
fee9ef0d 1279 switch (fAlgo) {
1280 case 1: StrLinVertexFinderMinDist(1); break;
1281 case 2: StrLinVertexFinderMinDist(0); break;
1282 case 3: HelixVertexFinder(); break;
1283 case 4: VertexFinder(1); break;
1284 case 5: VertexFinder(0); break;
1285 default: printf("Wrong algorithm\n"); break;
1286 }
50ff0bcd 1287
fee9ef0d 1288 if(fDebug) printf(" Vertex finding completed\n");
1289
1290 // vertex fitter
1291 if(optUseFitter){
3b768a1d 1292 //SetVtxStart(&fVert);
fee9ef0d 1293 VertexFitter(fConstraint);
1294 if(fDebug) printf(" Vertex fit completed\n");
1295 }else{
1296 Double_t position[3]={fVert.GetXv(),fVert.GetYv(),fVert.GetZv()};
146c29df 1297 Double_t covmatrix[6];
1298 fVert.GetCovMatrix(covmatrix);
fee9ef0d 1299 Double_t chi2=99999.;
1300 Int_t nUsedTrks=fVert.GetNContributors();
1301 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nUsedTrks);
1302 }
1303 fCurrentVertex->SetDispersion(fVert.GetDispersion());
1304
1305
1306 // set indices of used tracks and propagate track to found vertex
50ff0bcd 1307 UShort_t *indices = 0;
1308 AliESDtrack *eta = 0;
fee9ef0d 1309 if(fCurrentVertex->GetNContributors()>0) {
1310 indices = new UShort_t[fCurrentVertex->GetNContributors()];
50ff0bcd 1311 for(Int_t jj=0;jj<(Int_t)fTrkArray.GetEntriesFast();jj++) {
1312 eta = (AliESDtrack*)fTrkArray.At(jj);
1313 indices[jj] = (UShort_t)eta->GetID();
fee9ef0d 1314 if(optPropagate&&optUseFitter){
1315 if(TMath::Sqrt(fCurrentVertex->GetXv()*fCurrentVertex->GetXv()+fCurrentVertex->GetYv()*fCurrentVertex->GetYv())<3.) {
dc3719f3 1316 eta->RelateToVertex(fCurrentVertex,GetFieldkG(),100.);
fee9ef0d 1317 if(fDebug) printf("Track %d propagated to found vertex\n",jj);
1318 }else{
1319 AliWarning("Found vertex outside beam pipe!");
1320 }
1321 }
50ff0bcd 1322 }
fee9ef0d 1323 fCurrentVertex->SetIndices(fCurrentVertex->GetNContributors(),indices);
50ff0bcd 1324 }
1325 delete [] indices;
1326 fTrkArray.Delete();
1327
fee9ef0d 1328 return fCurrentVertex;
eae1677e 1329}
50ff0bcd 1330//----------------------------------------------------------------------------
fee9ef0d 1331AliESDVertex* AliVertexerTracks::VertexForSelectedTracks(TObjArray *trkArray,Bool_t optUseFitter, Bool_t optPropagate)
1332{
50ff0bcd 1333//
1334// Return vertex from array of tracks
1335//
5834e9a1 1336
50ff0bcd 1337 // get tracks and propagate them to initial vertex position
1338 Int_t nTrks = trkArray->GetEntriesFast();
0c69be49 1339 if(nTrks < TMath::Max(2,fMinTracks) ) {
50ff0bcd 1340 if(fDebug) printf("TooFewTracks\n");
fee9ef0d 1341 fCurrentVertex = new AliESDVertex(0.,0.,-1);
1342 return fCurrentVertex;
50ff0bcd 1343 }
1344 TTree *trkTree = new TTree("TreeT","tracks");
1345 AliESDtrack *esdTrack = 0;
1346 trkTree->Branch("tracks","AliESDtrack",&esdTrack);
1347 for(Int_t i=0; i<nTrks; i++){
1348 esdTrack = (AliESDtrack*)trkArray->At(i);
1349 trkTree->Fill();
1350 }
1351
fee9ef0d 1352 AliESDVertex *vtx = VertexForSelectedTracks(trkTree,optUseFitter,optPropagate);
50ff0bcd 1353 delete trkTree;
1354 return vtx;
1355}
1356//--------------------------------------------------------------------------