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Writing the ESDfriends to a separate branch of the ESD tree.
[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),
fe12e09c 45fMinTracks(2),
46fMinITSClusters(5),
07680cae 47fTrkArray(),
48fTrksToSkip(0),
49fNTrksToSkip(0),
50fDCAcut(0),
51fAlgo(1),
fe12e09c 52fNSigma(3),
50ff0bcd 53fITSin(kTRUE),
54fITSrefit(kTRUE),
07680cae 55fDebug(0)
2d57349e 56{
57//
58// Default constructor
59//
60 SetVtxStart();
07680cae 61 SetVtxStartSigma();
2d57349e 62 SetMinTracks();
07680cae 63 SetMinITSClusters();
64 SetNSigmad0();
2d57349e 65}
66//-----------------------------------------------------------------------------
67AliVertexerTracks::AliVertexerTracks(Double_t xStart, Double_t yStart):
07680cae 68TObject(),
69fVert(),
70fCurrentVertex(0),
fe12e09c 71fMinTracks(2),
72fMinITSClusters(5),
07680cae 73fTrkArray(),
74fTrksToSkip(0),
75fNTrksToSkip(0),
76fDCAcut(0),
77fAlgo(1),
fe12e09c 78fNSigma(3),
50ff0bcd 79fITSin(kTRUE),
80fITSrefit(kTRUE),
07680cae 81fDebug(0)
2d57349e 82{
83//
84// Standard constructor
85//
86 SetVtxStart(xStart,yStart);
07680cae 87 SetVtxStartSigma();
2d57349e 88 SetMinTracks();
07680cae 89 SetMinITSClusters();
90 SetNSigmad0();
2d57349e 91}
92//-----------------------------------------------------------------------------
93AliVertexerTracks::~AliVertexerTracks() {
94 // Default Destructor
eae1677e 95 // The objects pointed by the following pointer are not owned
2d57349e 96 // by this class and are not deleted
ec1be5d5 97 fCurrentVertex = 0;
07680cae 98 delete[] fTrksToSkip;
ec1be5d5 99}
c5e3e5d1 100//----------------------------------------------------------------------------
ec1be5d5 101AliESDVertex* AliVertexerTracks::FindPrimaryVertex(const AliESD *esdEvent)
102{
c5e3e5d1 103//
ec1be5d5 104// Primary vertex for current ESD event
eae1677e 105// (Two iterations:
106// 1st with 5*fNSigma*sigma(pt) cut w.r.t. to initial vertex;
107// 2nd with fNSigma*sigma(pt) cut w.r.t. to vertex found in 1st iteration)
318aecb9 108// All ESD tracks with inside the beam pipe are then propagated to found vertex
07680cae 109//
110 fCurrentVertex = 0;
111
50ff0bcd 112 Int_t nTrksTot = (Int_t)esdEvent->GetNumberOfTracks();
07680cae 113 TTree *trkTree = new TTree("TreeT","tracks");
114 AliESDtrack *esdTrack = 0;
115 trkTree->Branch("tracks","AliESDtrack",&esdTrack);
116
eae1677e 117 Bool_t skipThis;
50ff0bcd 118 for(Int_t i=0; i<nTrksTot; i++) {
eae1677e 119 // check tracks to skip
120 skipThis = kFALSE;
121 for(Int_t j=0; j<fNTrksToSkip; j++) {
122 if(i==fTrksToSkip[j]) {
123 if(fDebug) printf("skipping track: %d\n",i);
124 skipThis = kTRUE;
125 }
126 }
07680cae 127 AliESDtrack *et = esdEvent->GetTrack(i);
128 esdTrack = new AliESDtrack(*et);
50ff0bcd 129 if(skipThis) {delete esdTrack;continue;}
130 if(fITSin) {
131 if(!(esdTrack->GetStatus()&AliESDtrack::kITSin)) {delete esdTrack;continue;}
132 if(fITSrefit && !(esdTrack->GetStatus()&AliESDtrack::kITSrefit)) {delete esdTrack;continue;}
133 Int_t nclus=esdTrack->GetNcls(0); // check number of clusters in ITS
134 if(nclus<fMinITSClusters) {delete esdTrack;continue;}
135 }
07680cae 136 trkTree->Fill();
5834e9a1 137 delete esdTrack;
07680cae 138 }
318aecb9 139
07680cae 140
141 // ITERATION 1
142 // propagate tracks to initVertex
eae1677e 143 // preselect them (reject for |d0|>5*fNSigma*sigma w.r.t. initVertex)
50ff0bcd 144 Int_t nTrksPrep;
145 nTrksPrep = PrepareTracks(*trkTree,1);
146 if(fDebug) printf(" tracks prepared - step 1: %d\n",nTrksPrep);
147 if(nTrksPrep < fMinTracks) {
148 if(fDebug) printf("TooFewTracks\n");
eae1677e 149 TooFewTracks(esdEvent);
150 if(fDebug) fCurrentVertex->PrintStatus();
5834e9a1 151 fTrkArray.Delete();
152 delete trkTree;
07680cae 153 return fCurrentVertex;
154 }
155
156 // vertex finder
157 switch (fAlgo) {
158 case 1: StrLinVertexFinderMinDist(1); break;
159 case 2: StrLinVertexFinderMinDist(0); break;
160 case 3: HelixVertexFinder(); break;
161 case 4: VertexFinder(1); break;
162 case 5: VertexFinder(0); break;
163 default: printf("Wrong algorithm\n"); break;
164 }
165 if(fDebug) printf(" vertex finding completed\n");
166
167 // vertex fitter
eae1677e 168 VertexFitter(kTRUE);
07680cae 169 if(fDebug) printf(" vertex fit completed\n");
5834e9a1 170 fTrkArray.Delete();
07680cae 171 // ITERATION 2
172 // propagate tracks to best between initVertex and fCurrentVertex
173 // preselect tracks (reject for |d0|>fNSigma*sigma w.r.t. best
174 // between initVertex and fCurrentVertex)
50ff0bcd 175 nTrksPrep = PrepareTracks(*trkTree,2);
07680cae 176 delete trkTree;
50ff0bcd 177 if(fDebug) printf(" tracks prepared - step 2: %d\n",nTrksPrep);
178 if(nTrksPrep < fMinTracks) {
179 if(fDebug) printf("TooFewTracks\n");
eae1677e 180 TooFewTracks(esdEvent);
181 if(fDebug) fCurrentVertex->PrintStatus();
5834e9a1 182 fTrkArray.Delete();
07680cae 183 return fCurrentVertex;
184 }
185
186 // vertex finder
187 switch (fAlgo) {
188 case 1: StrLinVertexFinderMinDist(1); break;
189 case 2: StrLinVertexFinderMinDist(0); break;
190 case 3: HelixVertexFinder(); break;
191 case 4: VertexFinder(1); break;
192 case 5: VertexFinder(0); break;
193 default: printf("Wrong algorithm\n"); break;
194 }
195 if(fDebug) printf(" vertex finding completed\n");
196
197 // fitter
eae1677e 198 VertexFitter(kTRUE);
07680cae 199 if(fDebug) printf(" vertex fit completed\n");
200
eae1677e 201
eae1677e 202 // take true pos from ESD
07680cae 203 Double_t tp[3];
204 esdEvent->GetVertex()->GetTruePos(tp);
205 fCurrentVertex->SetTruePos(tp);
50ff0bcd 206 if(fNominalCov[0]>1.) {
eae1677e 207 fCurrentVertex->SetTitle("VertexerTracksNoConstraint");
208 } else {
209 fCurrentVertex->SetTitle("VertexerTracksWithConstraint");
210 }
211
318aecb9 212
213 // propagate tracks to found vertex
214 if(TMath::Sqrt(fCurrentVertex->GetXv()*fCurrentVertex->GetXv()+fCurrentVertex->GetYv()*fCurrentVertex->GetYv())<3.) {
50ff0bcd 215 for(Int_t ii=0; ii<nTrksTot; ii++) {
318aecb9 216 AliESDtrack *et = esdEvent->GetTrack(ii);
50ff0bcd 217 if(!(et->GetStatus()&AliESDtrack::kITSin)) continue;
318aecb9 218 if(et->GetX()>3.) continue;
219 et->RelateToVertex(fCurrentVertex,GetField(),100.);
220 }
221 } else {
222 AliWarning("Found vertex outside beam pipe!");
223 }
50ff0bcd 224
225 // set indices of used tracks
226 UShort_t *indices = 0;
227 AliESDtrack *ett = 0;
228 if(fCurrentVertex->GetNContributors()>0) {
229 indices = new UShort_t[fCurrentVertex->GetNContributors()];
230 for(Int_t jj=0;jj<(Int_t)fTrkArray.GetEntriesFast();jj++) {
231 ett = (AliESDtrack*)fTrkArray.At(jj);
232 indices[jj] = (UShort_t)ett->GetID();
233 }
234 fCurrentVertex->SetIndices(fCurrentVertex->GetNContributors(),indices);
235 }
236 delete [] indices;
237 fTrkArray.Delete();
238
239 if(fTrksToSkip) delete [] fTrksToSkip;
240
241
242 if(fDebug) fCurrentVertex->PrintStatus();
243 if(fDebug) fCurrentVertex->PrintIndices();
318aecb9 244
07680cae 245 return fCurrentVertex;
246}
50ff0bcd 247//------------------------------------------------------------------------
248Double_t AliVertexerTracks::GetDeterminant3X3(Double_t matr[][3]){
249 //
250 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];
251 return det;
252}
253//-------------------------------------------------------------------------
254void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t (*m)[3],Double_t *d){
ec1be5d5 255
50ff0bcd 256 //
257 Double_t x12=p0[0]-p1[0];
258 Double_t y12=p0[1]-p1[1];
259 Double_t z12=p0[2]-p1[2];
260 Double_t kk=x12*x12+y12*y12+z12*z12;
261 m[0][0]=2-2/kk*x12*x12;
262 m[0][1]=-2/kk*x12*y12;
263 m[0][2]=-2/kk*x12*z12;
264 m[1][0]=-2/kk*x12*y12;
265 m[1][1]=2-2/kk*y12*y12;
266 m[1][2]=-2/kk*y12*z12;
267 m[2][0]=-2/kk*x12*z12;
268 m[2][1]=-2*y12*z12;
269 m[2][2]=2-2/kk*z12*z12;
270 d[0]=2*p0[0]-2/kk*p0[0]*x12*x12-2/kk*p0[2]*x12*z12-2/kk*p0[1]*x12*y12;
271 d[1]=2*p0[1]-2/kk*p0[1]*y12*y12-2/kk*p0[0]*x12*y12-2/kk*p0[2]*z12*y12;
272 d[2]=2*p0[2]-2/kk*p0[2]*z12*z12-2/kk*p0[0]*x12*z12-2/kk*p0[1]*z12*y12;
c5e3e5d1 273
50ff0bcd 274}
275//--------------------------------------------------------------------------
276void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t *sigmasq,Double_t (*m)[3],Double_t *d){
277 //
278 Double_t x12=p1[0]-p0[0];
279 Double_t y12=p1[1]-p0[1];
280 Double_t z12=p1[2]-p0[2];
c5e3e5d1 281
50ff0bcd 282 Double_t den= x12*x12*sigmasq[1]*sigmasq[2]+y12*y12*sigmasq[0]*sigmasq[2]+z12*z12*sigmasq[0]*sigmasq[1];
c5e3e5d1 283
50ff0bcd 284 Double_t kk= 2*(x12*x12/sigmasq[0]+y12*y12/sigmasq[1]+z12*z12/sigmasq[2]);
c5e3e5d1 285
50ff0bcd 286 Double_t cc[3];
287 cc[0]=-x12/sigmasq[0];
288 cc[1]=-y12/sigmasq[1];
289 cc[2]=-z12/sigmasq[2];
ec1be5d5 290
50ff0bcd 291 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 292
50ff0bcd 293 Double_t ss= -p0[0]*cc[0]-p0[1]*cc[1]-p0[2]*cc[2];
2d57349e 294
50ff0bcd 295 Double_t aa[3];
296 aa[0]=x12*sigmasq[1]*sigmasq[2]/den;
297 aa[1]=y12*sigmasq[0]*sigmasq[2]/den;
298 aa[2]=z12*sigmasq[0]*sigmasq[1]/den;
2d57349e 299
50ff0bcd 300 m[0][0]=aa[0]*(aa[0]*kk+2*cc[0])+2*cc[0]*aa[0]+2/sigmasq[0];
301 m[0][1]=aa[1]*(aa[0]*kk+2*cc[0])+2*cc[1]*aa[0];
302 m[0][2]=aa[2]*(aa[0]*kk+2*cc[0])+2*cc[2]*aa[0];
2d57349e 303
50ff0bcd 304 m[1][0]=aa[0]*(aa[1]*kk+2*cc[1])+2*cc[0]*aa[1];
305 m[1][1]=aa[1]*(aa[1]*kk+2*cc[1])+2*cc[1]*aa[1]+2/sigmasq[1];
306 m[1][2]=aa[2]*(aa[1]*kk+2*cc[1])+2*cc[2]*aa[1];
2d57349e 307
50ff0bcd 308 m[2][0]=aa[0]*(aa[2]*kk+2*cc[2])+2*cc[0]*aa[2];
309 m[2][1]=aa[1]*(aa[2]*kk+2*cc[2])+2*cc[1]*aa[2];
310 m[2][2]=aa[2]*(aa[2]*kk+2*cc[2])+2*cc[2]*aa[2]+2/sigmasq[2];
08df6187 311
50ff0bcd 312 d[0]=-ww*(aa[0]*kk+2*cc[0])-2*ss*aa[0]+2*p0[0]/sigmasq[0];
313 d[1]=-ww*(aa[1]*kk+2*cc[1])-2*ss*aa[1]+2*p0[1]/sigmasq[1];
314 d[2]=-ww*(aa[2]*kk+2*cc[2])-2*ss*aa[2]+2*p0[2]/sigmasq[2];
2d57349e 315
2d57349e 316 }
50ff0bcd 317//--------------------------------------------------------------------------
318Double_t AliVertexerTracks::GetStrLinMinDist(Double_t *p0,Double_t *p1,Double_t *x0){
319 //
320 Double_t x12=p0[0]-p1[0];
321 Double_t y12=p0[1]-p1[1];
322 Double_t z12=p0[2]-p1[2];
323 Double_t x10=p0[0]-x0[0];
324 Double_t y10=p0[1]-x0[1];
325 Double_t z10=p0[2]-x0[2];
326 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 327}
328//---------------------------------------------------------------------------
329void AliVertexerTracks::HelixVertexFinder() {
330
331 // Get estimate of vertex position in (x,y) from tracks DCA
332
333
334 Double_t initPos[3];
335 initPos[2] = 0.;
336 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
337 Double_t field=GetField();
338
339 Int_t nacc = (Int_t)fTrkArray.GetEntriesFast();
340
341 Double_t aver[3]={0.,0.,0.};
342 Double_t averquad[3]={0.,0.,0.};
343 Double_t sigmaquad[3]={0.,0.,0.};
344 Double_t sigma=0;
345 Int_t ncombi = 0;
346 AliESDtrack *track1;
347 AliESDtrack *track2;
348 Double_t distCA;
349 Double_t x, par[5];
350 Double_t alpha, cs, sn;
351 Double_t crosspoint[3];
352 for(Int_t i=0; i<nacc; i++){
353 track1 = (AliESDtrack*)fTrkArray.At(i);
354
355
356 for(Int_t j=i+1; j<nacc; j++){
357 track2 = (AliESDtrack*)fTrkArray.At(j);
358
359 distCA=track2->PropagateToDCA(track1,field);
360
361 if(fDCAcut<=0 ||(fDCAcut>0&&distCA<fDCAcut)){
362 track1->GetExternalParameters(x,par);
363 alpha=track1->GetAlpha();
364 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
365 Double_t x1=x*cs - par[0]*sn;
366 Double_t y1=x*sn + par[0]*cs;
367 Double_t z1=par[1];
368 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
369 track2->GetExternalParameters(x,par);
370 alpha=track2->GetAlpha();
371 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
372 Double_t x2=x*cs - par[0]*sn;
373 Double_t y2=x*sn + par[0]*cs;
374 Double_t z2=par[1];
375 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
376 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
377 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
378 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
379 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
380 crosspoint[0]=wx1*x1 + wx2*x2;
381 crosspoint[1]=wy1*y1 + wy2*y2;
382 crosspoint[2]=wz1*z1 + wz2*z2;
383
384 ncombi++;
385 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
386 for(Int_t jj=0;jj<3;jj++)averquad[jj]+=(crosspoint[jj]*crosspoint[jj]);
387 }
388 }
389
390 }
391 if(ncombi>0){
392 for(Int_t jj=0;jj<3;jj++){
393 initPos[jj] = aver[jj]/ncombi;
394 averquad[jj]/=ncombi;
395 sigmaquad[jj]=averquad[jj]-initPos[jj]*initPos[jj];
396 sigma+=sigmaquad[jj];
397 }
398 sigma=TMath::Sqrt(TMath::Abs(sigma));
399 }
400 else {
401 Warning("HelixVertexFinder","Finder did not succed");
402 sigma=999;
403 }
404 fVert.SetXYZ(initPos);
405 fVert.SetDispersion(sigma);
406 fVert.SetNContributors(ncombi);
407}
50ff0bcd 408//----------------------------------------------------------------------------
409Int_t AliVertexerTracks::PrepareTracks(TTree &trkTree,Int_t OptImpParCut) {
410//
411// Propagate tracks to initial vertex position and store them in a TObjArray
412//
413 Double_t maxd0rphi = 3.;
414 Int_t nTrks = 0;
415 Double_t sigmaCurr[3];
416 Float_t d0z0[2],covd0z0[3];
417 Double_t sigma;
418 Double_t field=GetField();
419
420 AliESDVertex *initVertex = new AliESDVertex(fNominalPos,fNominalCov,1,1);
421
422 Int_t nEntries = (Int_t)trkTree.GetEntries();
423 if(!fTrkArray.IsEmpty()) fTrkArray.Delete();
424
425 if(fDebug) {
426 printf(" PrepareTracks()\n");
427 }
428
429 for(Int_t i=0; i<nEntries; i++) {
430 AliESDtrack *track = new AliESDtrack;
431 trkTree.SetBranchAddress("tracks",&track);
432 trkTree.GetEvent(i);
433
434 // propagate track to vertex
435 if(OptImpParCut==1) { // OptImpParCut==1
436 track->RelateToVertex(initVertex,field,100.);
437 } else { // OptImpParCut==2
438 fCurrentVertex->GetSigmaXYZ(sigmaCurr);
439 if((sigmaCurr[0]+sigmaCurr[1])<(TMath::Sqrt(fNominalCov[0])+TMath::Sqrt(fNominalCov[2]))) {
440 track->RelateToVertex(fCurrentVertex,field,100.);
441 } else {
442 track->RelateToVertex(initVertex,field,100.);
443 }
444 }
445
446 // select tracks with d0rphi < maxd0rphi
447 track->GetImpactParameters(d0z0,covd0z0);
448 sigma = TMath::Sqrt(covd0z0[0]);
449 maxd0rphi = fNSigma*sigma;
450 if(OptImpParCut==1) maxd0rphi *= 5.;
451
452 if(fDebug) printf("trk %d; lab %d; |d0| = %f; cut = %f\n",i,track->GetLabel(),TMath::Abs(d0z0[0]),maxd0rphi);
453 if(TMath::Abs(d0z0[0]) > maxd0rphi) {
454 if(fDebug) printf(" rejected\n");
455 delete track; continue;
456 }
457
458 fTrkArray.AddLast(track);
459 nTrks++;
460 }
461
462 delete initVertex;
463
464 return nTrks;
465}
466//---------------------------------------------------------------------------
467void AliVertexerTracks::SetSkipTracks(Int_t n,Int_t *skipped) {
468//
469// Mark the tracks not ot be used in the vertex finding
470//
471 fNTrksToSkip = n;
472 fTrksToSkip = new Int_t[n];
473 for(Int_t i=0;i<n;i++) fTrksToSkip[i] = skipped[i];
474 return;
475}
476//---------------------------------------------------------------------------
477void AliVertexerTracks::SetVtxStart(AliESDVertex *vtx) {
478//
479// Set initial vertex knowledge
480//
481 vtx->GetXYZ(fNominalPos);
482 vtx->GetCovMatrix(fNominalCov);
483 return;
484}
2d57349e 485//---------------------------------------------------------------------------
486void AliVertexerTracks::StrLinVertexFinderMinDist(Int_t optUseWeights){
487
488 // Calculate the point at minimum distance to prepared tracks
489
490 Double_t initPos[3];
491 initPos[2] = 0.;
492 Double_t sigma=0;
493 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
494 const Int_t knacc = (Int_t)fTrkArray.GetEntriesFast();
495 Double_t field=GetField();
496
497 AliESDtrack *track1;
498 Double_t (*vectP0)[3]=new Double_t [knacc][3];
499 Double_t (*vectP1)[3]=new Double_t [knacc][3];
500
501 Double_t sum[3][3];
502 Double_t dsum[3]={0,0,0};
503 for(Int_t i=0;i<3;i++)
504 for(Int_t j=0;j<3;j++)sum[i][j]=0;
505 for(Int_t i=0; i<knacc; i++){
506 track1 = (AliESDtrack*)fTrkArray.At(i);
507 Double_t alpha=track1->GetAlpha();
508 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
ec1be5d5 509 Double_t pos[3],dir[3];
510 track1->GetXYZAt(mindist,field,pos);
511 track1->GetPxPyPzAt(mindist,field,dir);
512 AliStrLine *line1 = new AliStrLine(pos,dir);
513 // AliStrLine *line1 = new AliStrLine();
514 // track1->ApproximateHelixWithLine(mindist,field,line1);
2d57349e 515
516 Double_t p0[3],cd[3];
517 line1->GetP0(p0);
518 line1->GetCd(cd);
519 Double_t p1[3]={p0[0]+cd[0],p0[1]+cd[1],p0[2]+cd[2]};
520 vectP0[i][0]=p0[0];
521 vectP0[i][1]=p0[1];
522 vectP0[i][2]=p0[2];
523 vectP1[i][0]=p1[0];
524 vectP1[i][1]=p1[1];
525 vectP1[i][2]=p1[2];
526
527 Double_t matr[3][3];
528 Double_t dknow[3];
529 if(optUseWeights==0)GetStrLinDerivMatrix(p0,p1,matr,dknow);
530 if(optUseWeights==1){
531 Double_t sigmasq[3];
532 sigmasq[0]=track1->GetSigmaY2();
533 sigmasq[1]=track1->GetSigmaY2();
534 sigmasq[2]=track1->GetSigmaZ2();
535 GetStrLinDerivMatrix(p0,p1,sigmasq,matr,dknow);
536 }
537
538 for(Int_t iii=0;iii<3;iii++){
539 dsum[iii]+=dknow[iii];
540 for(Int_t lj=0;lj<3;lj++) sum[iii][lj]+=matr[iii][lj];
541 }
542 delete line1;
543 }
544
545 Double_t vett[3][3];
546 Double_t det=GetDeterminant3X3(sum);
547
548 if(det!=0){
549 for(Int_t zz=0;zz<3;zz++){
550 for(Int_t ww=0;ww<3;ww++){
551 for(Int_t kk=0;kk<3;kk++) vett[ww][kk]=sum[ww][kk];
552 }
553 for(Int_t kk=0;kk<3;kk++) vett[kk][zz]=dsum[kk];
554 initPos[zz]=GetDeterminant3X3(vett)/det;
555 }
556
557
50ff0bcd 558 for(Int_t i=0; i<knacc; i++){
559 Double_t p0[3]={0,0,0},p1[3]={0,0,0};
560 for(Int_t ii=0;ii<3;ii++){
561 p0[ii]=vectP0[i][ii];
562 p1[ii]=vectP1[i][ii];
563 }
564 sigma+=GetStrLinMinDist(p0,p1,initPos);
565 }
2d57349e 566
50ff0bcd 567 sigma=TMath::Sqrt(sigma);
568 }else{
569 Warning("StrLinVertexFinderMinDist","Finder did not succed");
570 sigma=999;
571 }
572 delete vectP0;
573 delete vectP1;
574 fVert.SetXYZ(initPos);
575 fVert.SetDispersion(sigma);
576 fVert.SetNContributors(knacc);
577}
578//---------------------------------------------------------------------------
579void AliVertexerTracks::TooFewTracks(const AliESD* esdEvent) {
580//
581// When the number of tracks is < fMinTracks
582//
2d57349e 583
50ff0bcd 584 // deal with vertices not found
585 Double_t pos[3],err[3];
586 Int_t ncontr=0;
587 pos[0] = fNominalPos[0];
588 err[0] = TMath::Sqrt(fNominalCov[0]);
589 pos[1] = fNominalPos[1];
590 err[1] = TMath::Sqrt(fNominalCov[2]);
591 pos[2] = esdEvent->GetVertex()->GetZv();
592 err[2] = esdEvent->GetVertex()->GetZRes();
593 if(err[0]>1. && esdEvent->GetVertex()->GetNContributors()<=0)
594 ncontr = -1; // (x,y,z) = (0,0,0)
595 if(err[0]>1. && esdEvent->GetVertex()->GetNContributors()>0)
596 ncontr = -2; // (x,y,z) = (0,0,z_fromSPD)
597 if(err[0]<1. && esdEvent->GetVertex()->GetNContributors()<=0)
598 ncontr = -3; // (x,y,z) = (x_mean,y_mean,0)
599 if(err[0]<1. && esdEvent->GetVertex()->GetNContributors()>0)
600 ncontr = -4; // (x,y,z) = (x_mean,y_mean,z_fromSPD)
601 fCurrentVertex = 0;
602 fCurrentVertex = new AliESDVertex(pos,err);
603 fCurrentVertex->SetNContributors(ncontr);
2d57349e 604
50ff0bcd 605 Double_t tp[3];
606 esdEvent->GetVertex()->GetTruePos(tp);
607 fCurrentVertex->SetTruePos(tp);
608 fCurrentVertex->SetTitle("VertexerTracksWithConstraint");
609 if(ncontr==-1||ncontr==-2)
610 fCurrentVertex->SetTitle("VertexerTracksNoConstraint");
2d57349e 611
50ff0bcd 612 return;
613}
614//---------------------------------------------------------------------------
615void AliVertexerTracks::VertexFinder(Int_t optUseWeights) {
2d57349e 616
50ff0bcd 617 // Get estimate of vertex position in (x,y) from tracks DCA
618
619 Double_t initPos[3];
620 initPos[2] = 0.;
621 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
622 Int_t nacc = (Int_t)fTrkArray.GetEntriesFast();
623 Double_t aver[3]={0.,0.,0.};
624 Double_t aversq[3]={0.,0.,0.};
625 Double_t sigmasq[3]={0.,0.,0.};
626 Double_t sigma=0;
627 Int_t ncombi = 0;
628 AliESDtrack *track1;
629 AliESDtrack *track2;
630 Double_t pos[3],dir[3];
631 Double_t alpha,mindist;
632 Double_t field=GetField();
2d57349e 633
50ff0bcd 634 for(Int_t i=0; i<nacc; i++){
635 track1 = (AliESDtrack*)fTrkArray.At(i);
636 alpha=track1->GetAlpha();
637 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
638 track1->GetXYZAt(mindist,field,pos);
639 track1->GetPxPyPzAt(mindist,field,dir);
640 AliStrLine *line1 = new AliStrLine(pos,dir);
2d57349e 641
50ff0bcd 642 // AliStrLine *line1 = new AliStrLine();
643 // track1->ApproximateHelixWithLine(mindist,field,line1);
644
645 for(Int_t j=i+1; j<nacc; j++){
646 track2 = (AliESDtrack*)fTrkArray.At(j);
647 alpha=track2->GetAlpha();
648 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
649 track2->GetXYZAt(mindist,field,pos);
650 track2->GetPxPyPzAt(mindist,field,dir);
651 AliStrLine *line2 = new AliStrLine(pos,dir);
652 // AliStrLine *line2 = new AliStrLine();
653 // track2->ApproximateHelixWithLine(mindist,field,line2);
654 Double_t distCA=line2->GetDCA(line1);
655 if(fDCAcut<=0 || (fDCAcut>0&&distCA<fDCAcut)){
656 Double_t pnt1[3],pnt2[3],crosspoint[3];
2d57349e 657
50ff0bcd 658 if(optUseWeights<=0){
659 Int_t retcode = line2->Cross(line1,crosspoint);
660 if(retcode>=0){
661 ncombi++;
662 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
663 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
664 }
665 }
666 if(optUseWeights>0){
667 Int_t retcode = line1->CrossPoints(line2,pnt1,pnt2);
668 if(retcode>=0){
669 Double_t alpha, cs, sn;
670 alpha=track1->GetAlpha();
671 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
672 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
673 alpha=track2->GetAlpha();
674 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
675 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
676 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
677 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
678 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
679 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
680 crosspoint[0]=wx1*pnt1[0] + wx2*pnt2[0];
681 crosspoint[1]=wy1*pnt1[1] + wy2*pnt2[1];
682 crosspoint[2]=wz1*pnt1[2] + wz2*pnt2[2];
683
684 ncombi++;
685 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
686 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
687 }
688 }
689 }
690 delete line2;
691 }
692 delete line1;
71d84967 693 }
50ff0bcd 694 if(ncombi>0){
695 for(Int_t jj=0;jj<3;jj++){
696 initPos[jj] = aver[jj]/ncombi;
697 aversq[jj]/=ncombi;
698 sigmasq[jj]=aversq[jj]-initPos[jj]*initPos[jj];
699 sigma+=sigmasq[jj];
700 }
701 sigma=TMath::Sqrt(TMath::Abs(sigma));
702 }
703 else {
704 Warning("VertexFinder","Finder did not succed");
705 sigma=999;
706 }
707 fVert.SetXYZ(initPos);
708 fVert.SetDispersion(sigma);
709 fVert.SetNContributors(ncombi);
2d57349e 710}
ec1be5d5 711//---------------------------------------------------------------------------
07680cae 712void AliVertexerTracks::VertexFitter(Bool_t useNominalVtx) {
ec1be5d5 713//
714// The optimal estimate of the vertex position is given by a "weighted
715// average of tracks positions"
716// Original method: CMS Note 97/0051
717//
718 Double_t initPos[3];
719 fVert.GetXYZ(initPos);
720 if(fDebug) {
721 printf(" VertexFitter(): start\n");
722 printf(" Number of tracks in array: %d\n",(Int_t)fTrkArray.GetEntriesFast());
723 printf(" Minimum # tracks required in fit: %d\n",fMinTracks);
724 printf("Vertex position after finder: %f,%f,%f\n",initPos[0],initPos[1],initPos[2]);
50ff0bcd 725 if(useNominalVtx) 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 726 }
727
728 Int_t i,j,k,step=0;
729 TMatrixD rv(3,1);
730 TMatrixD vV(3,3);
731 rv(0,0) = initPos[0];
732 rv(1,0) = initPos[1];
733 rv(2,0) = 0.;
734 Double_t xlStart,alpha;
735 Double_t rotAngle;
736 Double_t cosRot,sinRot;
737 Double_t cc[15];
738 Int_t nUsedTrks;
739 Double_t chi2,chi2i;
740 Int_t arrEntries = (Int_t)fTrkArray.GetEntries();
741 AliESDtrack *t = 0;
742 Int_t failed = 0;
743
50ff0bcd 744 // initial vertex covariance matrix
745 TMatrixD vVb(3,3);
746 vVb(0,0) = fNominalCov[0];
747 vVb(0,1) = fNominalCov[1];
748 vVb(0,2) = 0.;
749 vVb(1,0) = fNominalCov[1];
750 vVb(1,1) = fNominalCov[2];
751 vVb(1,2) = 0.;
752 vVb(2,0) = 0.;
753 vVb(2,1) = 0.;
754 vVb(2,2) = fNominalCov[5];
755 TMatrixD vVbInv(TMatrixD::kInverted,vVb);
756 TMatrixD rb(3,1);
757 rb(0,0) = fNominalPos[0];
758 rb(1,0) = fNominalPos[1];
759 rb(2,0) = fNominalPos[2];
760 TMatrixD vVbInvrb(vVbInv,TMatrixD::kMult,rb);
761
762
eae1677e 763 // 2 steps:
764 // 1st - estimate of vtx using all tracks
765 // 2nd - estimate of global chi2
766 for(step=0; step<2; step++) {
ec1be5d5 767 if(fDebug) printf(" step = %d\n",step);
768 chi2 = 0.;
769 nUsedTrks = 0;
770
771 TMatrixD sumWiri(3,1);
772 TMatrixD sumWi(3,3);
773 for(i=0; i<3; i++) {
774 sumWiri(i,0) = 0.;
775 for(j=0; j<3; j++) sumWi(j,i) = 0.;
776 }
777
50ff0bcd 778
07680cae 779 if(useNominalVtx) {
50ff0bcd 780 for(i=0;i<3;i++) {
781 sumWiri(i,0) += vVbInvrb(i,0);
782 for(k=0;k<3;k++) sumWi(i,k) += vVbInv(i,k);
07680cae 783 }
784 }
785
786
ec1be5d5 787 // loop on tracks
788 for(k=0; k<arrEntries; k++) {
ec1be5d5 789 // get track from track array
790 t = (AliESDtrack*)fTrkArray.At(k);
791 alpha = t->GetAlpha();
792 xlStart = initPos[0]*TMath::Cos(alpha)+initPos[1]*TMath::Sin(alpha);
6c94f330 793 t->AliExternalTrackParam::PropagateTo(xlStart,AliTracker::GetBz()); // to vtxSeed
ec1be5d5 794 rotAngle = alpha;
795 if(alpha<0.) rotAngle += 2.*TMath::Pi();
796 cosRot = TMath::Cos(rotAngle);
797 sinRot = TMath::Sin(rotAngle);
798
799 // vector of track global coordinates
800 TMatrixD ri(3,1);
801 ri(0,0) = t->GetX()*cosRot-t->GetY()*sinRot;
802 ri(1,0) = t->GetX()*sinRot+t->GetY()*cosRot;
803 ri(2,0) = t->GetZ();
804
805 // matrix to go from global (x,y,z) to local (y,z);
806 TMatrixD qQi(2,3);
807 qQi(0,0) = -sinRot;
808 qQi(0,1) = cosRot;
809 qQi(0,2) = 0.;
810 qQi(1,0) = 0.;
811 qQi(1,1) = 0.;
812 qQi(1,2) = 1.;
813
814 // covariance matrix of local (y,z) - inverted
815 TMatrixD uUi(2,2);
816 t->GetExternalCovariance(cc);
817 uUi(0,0) = cc[0];
818 uUi(0,1) = cc[1];
819 uUi(1,0) = cc[1];
820 uUi(1,1) = cc[2];
821
822 // weights matrix: wWi = qQiT * uUiInv * qQi
823 if(uUi.Determinant() <= 0.) continue;
824 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
825 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
826 TMatrixD wWi(qQi,TMatrixD::kTransposeMult,uUiInvQi);
827
828 // track chi2
829 TMatrixD deltar = rv; deltar -= ri;
830 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
831 chi2i = deltar(0,0)*wWideltar(0,0)+
832 deltar(1,0)*wWideltar(1,0)+
833 deltar(2,0)*wWideltar(2,0);
834
835
ec1be5d5 836 // add to total chi2
837 chi2 += chi2i;
838
839 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
840
841 sumWiri += wWiri;
842 sumWi += wWi;
843
844 nUsedTrks++;
845 } // end loop on tracks
846
847 if(nUsedTrks < fMinTracks) {
848 failed=1;
849 continue;
850 }
851
852 Double_t determinant = sumWi.Determinant();
853 //cerr<<" determinant: "<<determinant<<endl;
854 if(determinant < 100.) {
855 printf("det(V) = 0\n");
856 failed=1;
857 continue;
858 }
859
860 // inverted of weights matrix
861 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
862 vV = invsumWi;
863
864 // position of primary vertex
865 rv.Mult(vV,sumWiri);
866
eae1677e 867 } // end loop on the 2 steps
ec1be5d5 868
5834e9a1 869 // delete t;
ec1be5d5 870
871 if(failed) {
50ff0bcd 872 if(fDebug) printf("TooFewTracks\n");
ec1be5d5 873 fCurrentVertex = new AliESDVertex(0.,0.,-1);
874 return;
875 }
876
877 Double_t position[3];
878 position[0] = rv(0,0);
879 position[1] = rv(1,0);
880 position[2] = rv(2,0);
881 Double_t covmatrix[6];
882 covmatrix[0] = vV(0,0);
883 covmatrix[1] = vV(0,1);
884 covmatrix[2] = vV(1,1);
885 covmatrix[3] = vV(0,2);
886 covmatrix[4] = vV(1,2);
887 covmatrix[5] = vV(2,2);
888
889 // store data in the vertex object
890 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nUsedTrks);
891
892 if(fDebug) {
893 printf(" VertexFitter(): finish\n");
894 printf(" rv = ( %f , %f , %f )\n\n",rv(0,0),rv(1,0),rv(2,0));
895 fCurrentVertex->PrintStatus();
896 }
897
898 return;
899}
50ff0bcd 900//----------------------------------------------------------------------------
901AliVertex* AliVertexerTracks::VertexForSelectedTracks(TTree *trkTree) {
eae1677e 902//
50ff0bcd 903// Return vertex from tracks in trkTree
eae1677e 904//
905
50ff0bcd 906 // get tracks and propagate them to initial vertex position
907 Int_t nTrksPrep = PrepareTracks(*trkTree,1);
908 if(nTrksPrep < fMinTracks) {
909 if(fDebug) printf("TooFewTracks\n");
910 Double_t vtx[3]={0,0,0};
911 fVert.SetXYZ(vtx);
912 fVert.SetDispersion(999);
913 fVert.SetNContributors(-5);
914 fTrkArray.Delete();
915 return &fVert;
916 }
917
918 // Set initial vertex position from ESD
919 if(fAlgo==1) StrLinVertexFinderMinDist(1);
920 if(fAlgo==2) StrLinVertexFinderMinDist(0);
921 if(fAlgo==3) HelixVertexFinder();
922 if(fAlgo==4) VertexFinder(1);
923 if(fAlgo==5) VertexFinder(0);
eae1677e 924
50ff0bcd 925
926 // set indices of used tracks
927 UShort_t *indices = 0;
928 AliESDtrack *eta = 0;
929 if(fVert.GetNContributors()>0) {
930 indices = new UShort_t[fVert.GetNContributors()];
931 for(Int_t jj=0;jj<(Int_t)fTrkArray.GetEntriesFast();jj++) {
932 eta = (AliESDtrack*)fTrkArray.At(jj);
933 indices[jj] = (UShort_t)eta->GetID();
934 }
935 fVert.SetIndices(fVert.GetNContributors(),indices);
936 }
937 delete [] indices;
938 fTrkArray.Delete();
939
940 return &fVert;
eae1677e 941}
50ff0bcd 942//----------------------------------------------------------------------------
943AliVertex* AliVertexerTracks::VertexForSelectedTracks(TObjArray *trkArray) {
944//
945// Return vertex from array of tracks
946//
5834e9a1 947
50ff0bcd 948 // get tracks and propagate them to initial vertex position
949 Int_t nTrks = trkArray->GetEntriesFast();
950 if(nTrks < fMinTracks) {
951 if(fDebug) printf("TooFewTracks\n");
952 Double_t vtx[3]={0,0,0};
953 fVert.SetXYZ(vtx);
954 fVert.SetDispersion(999);
955 fVert.SetNContributors(-5);
956 fTrkArray.Delete();
957 return &fVert;
958 }
959 TTree *trkTree = new TTree("TreeT","tracks");
960 AliESDtrack *esdTrack = 0;
961 trkTree->Branch("tracks","AliESDtrack",&esdTrack);
962 for(Int_t i=0; i<nTrks; i++){
963 esdTrack = (AliESDtrack*)trkArray->At(i);
964 trkTree->Fill();
965 }
966
967 AliVertex *vtx = VertexForSelectedTracks(trkTree);
968 delete trkTree;
969 return vtx;
970}
971//--------------------------------------------------------------------------