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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 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 <TSystem.h>
30#include <TClonesArray.h>
31#include <TDirectory.h>
32#include <TFile.h>
33//---- AliRoot headers -----
34#include "AliStrLine.h"
35#include "AliExternalTrackParam.h"
36#include "AliNeutralTrackParam.h"
37#include "AliVEvent.h"
38#include "AliVTrack.h"
39#include "AliESDtrack.h"
40#include "AliVertexerTracks.h"
41
42ClassImp(AliVertexerTracks)
43
44
45//----------------------------------------------------------------------------
46AliVertexerTracks::AliVertexerTracks():
47TObject(),
48fVert(),
49fCurrentVertex(0),
50fMode(0),
51fFieldkG(-999.),
52fTrkArraySel(),
53fIdSel(0),
54fTrksToSkip(0),
55fNTrksToSkip(0),
56fConstraint(kFALSE),
57fOnlyFitter(kFALSE),
58fMinTracks(1),
59fMinClusters(5),
60fDCAcut(0.1),
61fDCAcutIter0(0.1),
62fNSigma(3.),
63fMaxd0z0(0.5),
64fMinDetFitter(100.),
65fMaxTgl(1000.),
66fITSrefit(kTRUE),
67fITSpureSA(kFALSE),
68fFiducialR(3.),
69fFiducialZ(30.),
70fnSigmaForUi00(1.5),
71fAlgo(1),
72fAlgoIter0(4)
73{
74//
75// Default constructor
76//
77 SetVtxStart();
78 SetVtxStartSigma();
79}
80//----------------------------------------------------------------------------
81AliVertexerTracks::AliVertexerTracks(Double_t fieldkG):
82TObject(),
83fVert(),
84fCurrentVertex(0),
85fMode(0),
86fFieldkG(fieldkG),
87fTrkArraySel(),
88fIdSel(0),
89fTrksToSkip(0),
90fNTrksToSkip(0),
91fConstraint(kFALSE),
92fOnlyFitter(kFALSE),
93fMinTracks(1),
94fMinClusters(5),
95fDCAcut(0.1),
96fDCAcutIter0(0.1),
97fNSigma(3.),
98fMaxd0z0(0.5),
99fMinDetFitter(100.),
100fMaxTgl(1000.),
101fITSrefit(kTRUE),
102fITSpureSA(kFALSE),
103fFiducialR(3.),
104fFiducialZ(30.),
105fnSigmaForUi00(1.5),
106fAlgo(1),
107fAlgoIter0(4)
108{
109//
110// Standard constructor
111//
112 SetVtxStart();
113 SetVtxStartSigma();
114}
115//-----------------------------------------------------------------------------
116AliVertexerTracks::~AliVertexerTracks()
117{
118 // Default Destructor
119 // The objects pointed by the following pointer are not owned
120 // by this class and are not deleted
121 fCurrentVertex = 0;
122 if(fTrksToSkip) { delete [] fTrksToSkip; fTrksToSkip=NULL; }
123 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
124}
125//----------------------------------------------------------------------------
126AliESDVertex* AliVertexerTracks::FindPrimaryVertex(const AliVEvent *vEvent)
127{
128//
129// Primary vertex for current ESD or AOD event
130// (Two iterations:
131// 1st with 5*fNSigma*sigma cut w.r.t. to initial vertex
132// + cut on sqrt(d0d0+z0z0) if fConstraint=kFALSE
133// 2nd with fNSigma*sigma cut w.r.t. to vertex found in 1st iteration)
134//
135 fCurrentVertex = 0;
136
137 TString evtype = vEvent->IsA()->GetName();
138 Bool_t inputAOD = ((evtype=="AliAODEvent") ? kTRUE : kFALSE);
139
140 if(inputAOD && fMode==1) {
141 printf("Error : AliVertexerTracks: no TPC-only vertex from AOD\n");
142 TooFewTracks();
143 return fCurrentVertex;
144 }
145
146 // accept 1-track case only if constraint is available
147 if(!fConstraint && fMinTracks==1) fMinTracks=2;
148
149 // read tracks from AlivEvent
150 Int_t nTrks = (Int_t)vEvent->GetNumberOfTracks();
151 if(nTrks<fMinTracks) {
152 TooFewTracks();
153 return fCurrentVertex;
154 }
155 //
156
157 TDirectory * olddir = gDirectory;
158 TFile *f = 0;
159 if(nTrks>500) f = new TFile("VertexerTracks.root","recreate");
160 TObjArray trkArrayOrig(nTrks);
161 UShort_t *idOrig = new UShort_t[nTrks];
162
163 Int_t nTrksOrig=0;
164 AliExternalTrackParam *t=0;
165 // loop on tracks
166 for(Int_t i=0; i<nTrks; i++) {
167 AliVTrack *track = (AliVTrack*)vEvent->GetTrack(i);
168 // check tracks to skip
169 Bool_t skipThis = kFALSE;
170 for(Int_t j=0; j<fNTrksToSkip; j++) {
171 if(track->GetID()==fTrksToSkip[j]) {
172 AliDebug(1,Form("skipping track: %d",i));
173 skipThis = kTRUE;
174 }
175 }
176 if(skipThis) continue;
177
178 // skip pure ITS SA tracks (default)
179 if(!fITSpureSA && (track->GetStatus()&AliESDtrack::kITSpureSA)) continue;
180 // or use only pure ITS SA tracks
181 if(fITSpureSA && !(track->GetStatus()&AliESDtrack::kITSpureSA)) continue;
182
183 // kITSrefit
184 if(fMode==0 && fITSrefit && !(track->GetStatus()&AliESDtrack::kITSrefit)) continue;
185
186 if(!inputAOD) { // ESD
187 AliESDtrack* esdt = (AliESDtrack*)track;
188 if(esdt->GetNcls(fMode) < fMinClusters) continue;
189 if(fMode==0) { // ITS mode
190 Double_t x,p[5],cov[15];
191 esdt->GetExternalParameters(x,p);
192 esdt->GetExternalCovariance(cov);
193 t = new AliExternalTrackParam(x,esdt->GetAlpha(),p,cov);
194 } else if(fMode==1) { // TPC mode
195 t = (AliExternalTrackParam*)esdt->GetTPCInnerParam();
196 if(!t) continue;
197 Double_t radius = 2.8; //something less than the beam pipe radius
198 if(!PropagateTrackTo(t,radius)) continue;
199 }
200 } else { // AOD (only ITS mode)
201 Int_t ncls0=0;
202 for(Int_t l=0;l<6;l++) if(TESTBIT(track->GetITSClusterMap(),l)) ncls0++;
203 if(ncls0 < fMinClusters) continue;
204 t = new AliExternalTrackParam(track);
205 }
206 trkArrayOrig.AddLast(t);
207 idOrig[nTrksOrig]=(UShort_t)track->GetID();
208 nTrksOrig++;
209 } // end loop on tracks
210
211 // call method that will reconstruct the vertex
212 FindPrimaryVertex(&trkArrayOrig,idOrig);
213
214 if(fMode==0) trkArrayOrig.Delete();
215 delete [] idOrig; idOrig=NULL;
216
217 if(f) {
218 f->Close(); delete f; f = NULL;
219 gSystem->Unlink("VertexerTracks.root");
220 olddir->cd();
221 }
222
223 // set vertex ID for tracks used in the fit
224 // (only for ESD)
225 if(!inputAOD) {
226 Int_t nIndices = fCurrentVertex->GetNIndices();
227 UShort_t *indices = fCurrentVertex->GetIndices();
228 for(Int_t ind=0; ind<nIndices; ind++) {
229 AliESDtrack *esdt = (AliESDtrack*)vEvent->GetTrack(indices[ind]);
230 esdt->SetVertexID(-1);
231 }
232 }
233
234 return fCurrentVertex;
235}
236//----------------------------------------------------------------------------
237AliESDVertex* AliVertexerTracks::FindPrimaryVertex(const TObjArray *trkArrayOrig,
238 UShort_t *idOrig)
239{
240//
241// Primary vertex using the AliExternalTrackParam's in the TObjArray.
242// idOrig must contain the track IDs from AliESDtrack::GetID()
243// (Two iterations:
244// 1st with 5*fNSigma*sigma cut w.r.t. to initial vertex
245// + cut on sqrt(d0d0+z0z0) if fConstraint=kFALSE
246// 2nd with fNSigma*sigma cut w.r.t. to vertex found in 1st iteration)
247//
248 fCurrentVertex = 0;
249
250 // accept 1-track case only if constraint is available
251 if(!fConstraint && fMinTracks==1) fMinTracks=2;
252
253 // read tracks from array
254 Int_t nTrksOrig = (Int_t)trkArrayOrig->GetEntriesFast();
255 AliDebug(1,Form("Initial number of tracks: %d",nTrksOrig));
256 if(nTrksOrig<fMinTracks) {
257 AliDebug(1,"TooFewTracks");
258 TooFewTracks();
259 return fCurrentVertex;
260 }
261
262 // If fConstraint=kFALSE
263 // run VertexFinder(1) to get rough estimate of initVertex (x,y)
264 if(!fConstraint) {
265 // fill fTrkArraySel, for VertexFinder()
266 fIdSel = new UShort_t[nTrksOrig];
267 PrepareTracks(*trkArrayOrig,idOrig,0);
268 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
269 Double_t cutsave = fDCAcut;
270 fDCAcut = fDCAcutIter0;
271 // vertex finder
272 switch (fAlgoIter0) {
273 case 1: StrLinVertexFinderMinDist(1); break;
274 case 2: StrLinVertexFinderMinDist(0); break;
275 case 3: HelixVertexFinder(); break;
276 case 4: VertexFinder(1); break;
277 case 5: VertexFinder(0); break;
278 default: printf("Wrong algorithm\n"); break;
279 }
280 fDCAcut = cutsave;
281 if(fVert.GetNContributors()>0) {
282 fVert.GetXYZ(fNominalPos);
283 fNominalPos[0] = fVert.GetXv();
284 fNominalPos[1] = fVert.GetYv();
285 fNominalPos[2] = fVert.GetZv();
286 AliDebug(1,Form("No mean vertex: VertexFinder gives (%f, %f, %f)",fNominalPos[0],fNominalPos[1],fNominalPos[2]));
287 } else {
288 fNominalPos[0] = 0.;
289 fNominalPos[1] = 0.;
290 fNominalPos[2] = 0.;
291 AliDebug(1,"No mean vertex and VertexFinder failed");
292 }
293 }
294
295 // TWO ITERATIONS:
296 //
297 // ITERATION 1
298 // propagate tracks to fNominalPos vertex
299 // preselect them:
300 // if(constraint) reject for |d0|>5*fNSigma*sigma w.r.t. fNominal... vertex
301 // else reject for |d0|\oplus|z0| > 5 mm w.r.t. fNominal... vertex
302 // ITERATION 2
303 // propagate tracks to best between initVertex and fCurrentVertex
304 // preselect tracks (reject for |d0|>fNSigma*sigma w.r.t. best
305 // between initVertex and fCurrentVertex)
306 for(Int_t iter=1; iter<=2; iter++) {
307 if(fOnlyFitter && iter==1) continue;
308 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
309 fIdSel = new UShort_t[nTrksOrig];
310 Int_t nTrksSel = PrepareTracks(*trkArrayOrig,idOrig,iter);
311 AliDebug(1,Form("N tracks selected in iteration %d: %d",iter,nTrksSel));
312 if(nTrksSel < fMinTracks) {
313 TooFewTracks();
314 return fCurrentVertex;
315 }
316
317 // vertex finder
318 if(!fOnlyFitter) {
319 if(nTrksSel==1) {
320 AliDebug(1,"Just one track");
321 OneTrackVertFinder();
322 } else {
323 switch (fAlgo) {
324 case 1: StrLinVertexFinderMinDist(1); break;
325 case 2: StrLinVertexFinderMinDist(0); break;
326 case 3: HelixVertexFinder(); break;
327 case 4: VertexFinder(1); break;
328 case 5: VertexFinder(0); break;
329 default: printf("Wrong algorithm"); break;
330 }
331 }
332 AliDebug(1," Vertex finding completed");
333 }
334
335 // vertex fitter
336 VertexFitter();
337 } // end loop on the two iterations
338
339
340 // set indices of used tracks
341 UShort_t *indices = 0;
342 if(fCurrentVertex->GetNContributors()>0) {
343 Int_t nIndices = (Int_t)fTrkArraySel.GetEntriesFast();
344 indices = new UShort_t[nIndices];
345 for(Int_t jj=0; jj<nIndices; jj++)
346 indices[jj] = fIdSel[jj];
347 fCurrentVertex->SetIndices(nIndices,indices);
348 }
349 if (indices) {delete [] indices; indices=NULL;}
350 //
351
352 // set vertex title
353 TString title="VertexerTracksNoConstraint";
354 if(fConstraint) {
355 title="VertexerTracksWithConstraint";
356 if(fOnlyFitter) title.Append("OnlyFitter");
357 }
358 fCurrentVertex->SetTitle(title.Data());
359 //
360
361 AliDebug(1,Form("xyz: %f %f %f; nc %d",fCurrentVertex->GetXv(),fCurrentVertex->GetYv(),fCurrentVertex->GetZv(),fCurrentVertex->GetNContributors()));
362
363 // clean up
364 delete [] fIdSel; fIdSel=NULL;
365 fTrkArraySel.Delete();
366 if(fTrksToSkip) { delete [] fTrksToSkip; fTrksToSkip=NULL; }
367 //
368
369 return fCurrentVertex;
370}
371//------------------------------------------------------------------------
372Double_t AliVertexerTracks::GetDeterminant3X3(Double_t matr[][3])
373{
374 //
375 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];
376 return det;
377}
378//-------------------------------------------------------------------------
379void AliVertexerTracks::GetStrLinDerivMatrix(const Double_t *p0,const Double_t *p1,Double_t (*m)[3],Double_t *d)
380{
381 //
382 Double_t x12=p0[0]-p1[0];
383 Double_t y12=p0[1]-p1[1];
384 Double_t z12=p0[2]-p1[2];
385 Double_t kk=x12*x12+y12*y12+z12*z12;
386 m[0][0]=2-2/kk*x12*x12;
387 m[0][1]=-2/kk*x12*y12;
388 m[0][2]=-2/kk*x12*z12;
389 m[1][0]=-2/kk*x12*y12;
390 m[1][1]=2-2/kk*y12*y12;
391 m[1][2]=-2/kk*y12*z12;
392 m[2][0]=-2/kk*x12*z12;
393 m[2][1]=-2*y12*z12;
394 m[2][2]=2-2/kk*z12*z12;
395 d[0]=2*p0[0]-2/kk*p0[0]*x12*x12-2/kk*p0[2]*x12*z12-2/kk*p0[1]*x12*y12;
396 d[1]=2*p0[1]-2/kk*p0[1]*y12*y12-2/kk*p0[0]*x12*y12-2/kk*p0[2]*z12*y12;
397 d[2]=2*p0[2]-2/kk*p0[2]*z12*z12-2/kk*p0[0]*x12*z12-2/kk*p0[1]*z12*y12;
398
399}
400//--------------------------------------------------------------------------
401void AliVertexerTracks::GetStrLinDerivMatrix(const Double_t *p0,const Double_t *p1,const Double_t *sigmasq,Double_t (*m)[3],Double_t *d)
402{
403 //
404 Double_t x12=p1[0]-p0[0];
405 Double_t y12=p1[1]-p0[1];
406 Double_t z12=p1[2]-p0[2];
407
408 Double_t den= x12*x12*sigmasq[1]*sigmasq[2]+y12*y12*sigmasq[0]*sigmasq[2]+z12*z12*sigmasq[0]*sigmasq[1];
409
410 Double_t kk= 2*(x12*x12/sigmasq[0]+y12*y12/sigmasq[1]+z12*z12/sigmasq[2]);
411
412 Double_t cc[3];
413 cc[0]=-x12/sigmasq[0];
414 cc[1]=-y12/sigmasq[1];
415 cc[2]=-z12/sigmasq[2];
416
417 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;
418
419 Double_t ss= -p0[0]*cc[0]-p0[1]*cc[1]-p0[2]*cc[2];
420
421 Double_t aa[3];
422 aa[0]=x12*sigmasq[1]*sigmasq[2]/den;
423 aa[1]=y12*sigmasq[0]*sigmasq[2]/den;
424 aa[2]=z12*sigmasq[0]*sigmasq[1]/den;
425
426 m[0][0]=aa[0]*(aa[0]*kk+2*cc[0])+2*cc[0]*aa[0]+2/sigmasq[0];
427 m[0][1]=aa[1]*(aa[0]*kk+2*cc[0])+2*cc[1]*aa[0];
428 m[0][2]=aa[2]*(aa[0]*kk+2*cc[0])+2*cc[2]*aa[0];
429
430 m[1][0]=aa[0]*(aa[1]*kk+2*cc[1])+2*cc[0]*aa[1];
431 m[1][1]=aa[1]*(aa[1]*kk+2*cc[1])+2*cc[1]*aa[1]+2/sigmasq[1];
432 m[1][2]=aa[2]*(aa[1]*kk+2*cc[1])+2*cc[2]*aa[1];
433
434 m[2][0]=aa[0]*(aa[2]*kk+2*cc[2])+2*cc[0]*aa[2];
435 m[2][1]=aa[1]*(aa[2]*kk+2*cc[2])+2*cc[1]*aa[2];
436 m[2][2]=aa[2]*(aa[2]*kk+2*cc[2])+2*cc[2]*aa[2]+2/sigmasq[2];
437
438 d[0]=-ww*(aa[0]*kk+2*cc[0])-2*ss*aa[0]+2*p0[0]/sigmasq[0];
439 d[1]=-ww*(aa[1]*kk+2*cc[1])-2*ss*aa[1]+2*p0[1]/sigmasq[1];
440 d[2]=-ww*(aa[2]*kk+2*cc[2])-2*ss*aa[2]+2*p0[2]/sigmasq[2];
441
442 }
443//--------------------------------------------------------------------------
444Double_t AliVertexerTracks::GetStrLinMinDist(const Double_t *p0,const Double_t *p1,const Double_t *x0)
445{
446 //
447 Double_t x12=p0[0]-p1[0];
448 Double_t y12=p0[1]-p1[1];
449 Double_t z12=p0[2]-p1[2];
450 Double_t x10=p0[0]-x0[0];
451 Double_t y10=p0[1]-x0[1];
452 Double_t z10=p0[2]-x0[2];
453 // 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);
454 return ((y10*z12-z10*y12)*(y10*z12-z10*y12)+
455 (z10*x12-x10*z12)*(z10*x12-x10*z12)+
456 (x10*y12-y10*x12)*(x10*y12-y10*x12))
457 /(x12*x12+y12*y12+z12*z12);
458}
459//---------------------------------------------------------------------------
460void AliVertexerTracks::OneTrackVertFinder()
461{
462 // find vertex for events with 1 track, using DCA to nominal beam axis
463 AliDebug(1,Form("Number of prepared tracks =%d - Call OneTrackVertFinder",fTrkArraySel.GetEntries()));
464 AliExternalTrackParam *track1;
465 track1 = (AliExternalTrackParam*)fTrkArraySel.At(0);
466 Double_t alpha=track1->GetAlpha();
467 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
468 Double_t pos[3],dir[3];
469 track1->GetXYZAt(mindist,GetFieldkG(),pos);
470 track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
471 AliStrLine *line1 = new AliStrLine(pos,dir);
472 Double_t p1[3]={fNominalPos[0],fNominalPos[1],0.};
473 Double_t p2[3]={fNominalPos[0],fNominalPos[1],10.};
474 AliStrLine *zeta=new AliStrLine(p1,p2,kTRUE);
475 Double_t crosspoint[3]={0.,0.,0.};
476 Double_t sigma=999.;
477 Int_t nContrib=-1;
478 Int_t retcode = zeta->Cross(line1,crosspoint);
479 if(retcode>=0){
480 sigma=line1->GetDistFromPoint(crosspoint);
481 nContrib=1;
482 }
483 delete zeta;
484 delete line1;
485 fVert.SetXYZ(crosspoint);
486 fVert.SetDispersion(sigma);
487 fVert.SetNContributors(nContrib);
488}
489//---------------------------------------------------------------------------
490void AliVertexerTracks::HelixVertexFinder()
491{
492 // Get estimate of vertex position in (x,y) from tracks DCA
493
494
495 Double_t initPos[3];
496 initPos[2] = 0.;
497 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
498
499 Int_t nacc = (Int_t)fTrkArraySel.GetEntriesFast();
500
501 Double_t aver[3]={0.,0.,0.};
502 Double_t averquad[3]={0.,0.,0.};
503 Double_t sigmaquad[3]={0.,0.,0.};
504 Double_t sigma=0;
505 Int_t ncombi = 0;
506 AliExternalTrackParam *track1;
507 AliExternalTrackParam *track2;
508 Double_t distCA;
509 Double_t x;
510 Double_t alpha, cs, sn;
511 Double_t crosspoint[3];
512 for(Int_t i=0; i<nacc; i++){
513 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
514
515
516 for(Int_t j=i+1; j<nacc; j++){
517 track2 = (AliExternalTrackParam*)fTrkArraySel.At(j);
518
519 distCA=track2->PropagateToDCA(track1,GetFieldkG());
520 if(fDCAcut<=0 ||(fDCAcut>0&&distCA<fDCAcut)){
521 x=track1->GetX();
522 alpha=track1->GetAlpha();
523 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
524 Double_t x1=x*cs - track1->GetY()*sn;
525 Double_t y1=x*sn + track1->GetY()*cs;
526 Double_t z1=track1->GetZ();
527
528 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
529 x=track2->GetX();
530 alpha=track2->GetAlpha();
531 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
532 Double_t x2=x*cs - track2->GetY()*sn;
533 Double_t y2=x*sn + track2->GetY()*cs;
534 Double_t z2=track2->GetZ();
535 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
536 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
537 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
538 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
539 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
540 crosspoint[0]=wx1*x1 + wx2*x2;
541 crosspoint[1]=wy1*y1 + wy2*y2;
542 crosspoint[2]=wz1*z1 + wz2*z2;
543
544 ncombi++;
545 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
546 for(Int_t jj=0;jj<3;jj++)averquad[jj]+=(crosspoint[jj]*crosspoint[jj]);
547 }
548 }
549
550 }
551 if(ncombi>0){
552 for(Int_t jj=0;jj<3;jj++){
553 initPos[jj] = aver[jj]/ncombi;
554 averquad[jj]/=ncombi;
555 sigmaquad[jj]=averquad[jj]-initPos[jj]*initPos[jj];
556 sigma+=sigmaquad[jj];
557 }
558 sigma=TMath::Sqrt(TMath::Abs(sigma));
559 }
560 else {
561 Warning("HelixVertexFinder","Finder did not succed");
562 sigma=999;
563 }
564 fVert.SetXYZ(initPos);
565 fVert.SetDispersion(sigma);
566 fVert.SetNContributors(ncombi);
567}
568//----------------------------------------------------------------------------
569Int_t AliVertexerTracks::PrepareTracks(const TObjArray &trkArrayOrig,
570 const UShort_t *idOrig,
571 Int_t optImpParCut)
572{
573//
574// Propagate tracks to initial vertex position and store them in a TObjArray
575//
576 AliDebug(1," PrepareTracks()");
577
578 Int_t nTrksOrig = (Int_t)trkArrayOrig.GetEntriesFast();
579 Int_t nTrksSel = 0;
580 Double_t maxd0rphi;
581 Double_t sigmaCurr[3];
582 Double_t normdistx,normdisty;
583 Double_t d0z0[2],covd0z0[3];
584 Double_t sigmad0;
585
586 AliESDVertex *initVertex = new AliESDVertex(fNominalPos,fNominalCov,1,1);
587
588 if(!fTrkArraySel.IsEmpty()) fTrkArraySel.Delete();
589
590 AliExternalTrackParam *track=0;
591
592 // loop on tracks
593 for(Int_t i=0; i<nTrksOrig; i++) {
594 AliExternalTrackParam *trackOrig=(AliExternalTrackParam*)trkArrayOrig.At(i);
595 if(trackOrig->Charge()!=0) { // normal tracks
596 track = new AliExternalTrackParam(*(AliExternalTrackParam*)trkArrayOrig.At(i));
597 } else { // neutral tracks (from a V0)
598 track = new AliNeutralTrackParam(*(AliNeutralTrackParam*)trkArrayOrig.At(i));
599 }
600
601 // tgl cut
602 if(TMath::Abs(track->GetTgl())>fMaxTgl) {
603 AliDebug(1,Form(" rejecting track with tgl = %f",track->GetTgl()));
604 delete track; continue;
605 }
606
607 Bool_t propagateOK = kFALSE, cutond0z0 = kTRUE;
608 // propagate track to vertex
609 if(optImpParCut<2 || fOnlyFitter) { // optImpParCut==1 or 0
610 propagateOK = track->PropagateToDCA(initVertex,GetFieldkG(),100.,d0z0,covd0z0);
611 } else { // optImpParCut==2
612 fCurrentVertex->GetSigmaXYZ(sigmaCurr);
613 normdistx = TMath::Abs(fCurrentVertex->GetXv()-fNominalPos[0])/TMath::Sqrt(sigmaCurr[0]*sigmaCurr[0]+fNominalCov[0]);
614 normdisty = TMath::Abs(fCurrentVertex->GetYv()-fNominalPos[1])/TMath::Sqrt(sigmaCurr[1]*sigmaCurr[1]+fNominalCov[2]);
615 AliDebug(1,Form("normdistx %f %f %f",fCurrentVertex->GetXv(),fNominalPos[0],TMath::Sqrt(sigmaCurr[0]*sigmaCurr[0]+fNominalCov[0])));
616 AliDebug(1,Form("normdisty %f %f %f",fCurrentVertex->GetYv(),fNominalPos[1],TMath::Sqrt(sigmaCurr[1]*sigmaCurr[1]+fNominalCov[2])));
617 AliDebug(1,Form("sigmaCurr %f %f %f",sigmaCurr[0],sigmaCurr[1],TMath::Sqrt(fNominalCov[0])+TMath::Sqrt(fNominalCov[2])));
618 if(normdistx < 3. && normdisty < 3. &&
619 (sigmaCurr[0]+sigmaCurr[1])<(TMath::Sqrt(fNominalCov[0])+TMath::Sqrt(fNominalCov[2]))) {
620 propagateOK = track->PropagateToDCA(fCurrentVertex,GetFieldkG(),100.,d0z0,covd0z0);
621 } else {
622 propagateOK = track->PropagateToDCA(initVertex,GetFieldkG(),100.,d0z0,covd0z0);
623 if(fConstraint) cutond0z0=kFALSE;
624 }
625 }
626
627 if(!propagateOK) {
628 AliDebug(1," rejected");
629 delete track; continue;
630 }
631
632 sigmad0 = TMath::Sqrt(covd0z0[0]);
633 maxd0rphi = fNSigma*sigmad0;
634 if(optImpParCut==1) maxd0rphi *= 5.;
635 maxd0rphi = TMath::Min(maxd0rphi,fFiducialR);
636 //sigmad0z0 = TMath::Sqrt(covd0z0[0]+covd0z0[2]);
637
638 AliDebug(1,Form("trk %d; id %d; |d0| = %f; d0 cut = %f; |z0| = %f; |d0|oplus|z0| = %f; d0z0 cut = %f",i,(Int_t)idOrig[i],TMath::Abs(d0z0[0]),maxd0rphi,TMath::Abs(d0z0[1]),TMath::Sqrt(d0z0[0]*d0z0[0]+d0z0[1]*d0z0[1]),fMaxd0z0));
639
640
641 //---- track selection based on impact parameters ----//
642
643 // always reject tracks outside fiducial volume
644 if(TMath::Abs(d0z0[0])>fFiducialR || TMath::Abs(d0z0[1])>fFiducialZ) {
645 AliDebug(1," rejected");
646 delete track; continue;
647 }
648
649 // during iterations 1 and 2 , reject tracks with d0rphi > maxd0rphi
650 if(optImpParCut>0 && TMath::Abs(d0z0[0])>maxd0rphi) {
651 AliDebug(1," rejected");
652 delete track; continue;
653 }
654
655 // if fConstraint=kFALSE, during iterations 1 and 2 ||
656 // if fConstraint=kTRUE, during iteration 2,
657 // select tracks with d0oplusz0 < fMaxd0z0
658 if((!fConstraint && optImpParCut>0 && fVert.GetNContributors()>0) ||
659 ( fConstraint && optImpParCut==2 && cutond0z0)) {
660 if(nTrksOrig>=3 &&
661 TMath::Sqrt(d0z0[0]*d0z0[0]+d0z0[1]*d0z0[1])>fMaxd0z0) {
662 AliDebug(1," rejected");
663 delete track; continue;
664 }
665 }
666
667 // track passed all selections
668 fTrkArraySel.AddLast(track);
669 fIdSel[nTrksSel] = idOrig[i];
670 nTrksSel++;
671 } // end loop on tracks
672
673 delete initVertex;
674
675 return nTrksSel;
676}
677//----------------------------------------------------------------------------
678Bool_t AliVertexerTracks::PropagateTrackTo(AliExternalTrackParam *track,
679 Double_t xToGo) {
680 //----------------------------------------------------------------
681 // COPIED from AliTracker
682 //
683 // Propagates the track to the plane X=xk (cm).
684 //
685 // Origin: Marian Ivanov, Marian.Ivanov@cern.ch
686 //----------------------------------------------------------------
687
688 const Double_t kEpsilon = 0.00001;
689 Double_t xpos = track->GetX();
690 Double_t dir = (xpos<xToGo) ? 1. : -1.;
691 Double_t maxStep = 5;
692 Double_t maxSnp = 0.8;
693 //
694 while ( (xToGo-xpos)*dir > kEpsilon){
695 Double_t step = dir*TMath::Min(TMath::Abs(xToGo-xpos), maxStep);
696 Double_t x = xpos+step;
697 Double_t xyz0[3],xyz1[3];
698 track->GetXYZ(xyz0); //starting global position
699
700 if(!track->GetXYZAt(x,GetFieldkG(),xyz1)) return kFALSE; // no prolongation
701 xyz1[2]+=kEpsilon; // waiting for bug correction in geo
702
703 if(TMath::Abs(track->GetSnpAt(x,GetFieldkG())) >= maxSnp) return kFALSE;
704 if(!track->PropagateTo(x,GetFieldkG())) return kFALSE;
705
706 if(TMath::Abs(track->GetSnp()) >= maxSnp) return kFALSE;
707 track->GetXYZ(xyz0); // global position
708 Double_t alphan = TMath::ATan2(xyz0[1], xyz0[0]);
709 //
710 Double_t ca=TMath::Cos(alphan-track->GetAlpha()),
711 sa=TMath::Sin(alphan-track->GetAlpha());
712 Double_t sf=track->GetSnp(), cf=TMath::Sqrt((1.-sf)*(1.+sf));
713 Double_t sinNew = sf*ca - cf*sa;
714 if(TMath::Abs(sinNew) >= maxSnp) return kFALSE;
715 if(!track->Rotate(alphan)) return kFALSE;
716
717 xpos = track->GetX();
718 }
719 return kTRUE;
720}
721//---------------------------------------------------------------------------
722AliESDVertex* AliVertexerTracks::RemoveTracksFromVertex(AliESDVertex *inVtx,
723 const TObjArray *trkArray,
724 UShort_t *id,
725 const Float_t *diamondxy) const
726{
727//
728// Removes tracks in trksTree from fit of inVtx
729//
730
731 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraint")) {
732 printf("ERROR: primary vertex has no constraint: cannot remove tracks");
733 return 0x0;
734 }
735 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraintOnlyFitter"))
736 printf("WARNING: result of tracks' removal will be only approximately correct");
737
738 TMatrixD rv(3,1);
739 rv(0,0) = inVtx->GetXv();
740 rv(1,0) = inVtx->GetYv();
741 rv(2,0) = inVtx->GetZv();
742 TMatrixD vV(3,3);
743 Double_t cov[6];
744 inVtx->GetCovMatrix(cov);
745 vV(0,0) = cov[0];
746 vV(0,1) = cov[1]; vV(1,0) = cov[1];
747 vV(1,1) = cov[2];
748 vV(0,2) = cov[3]; vV(2,0) = cov[3];
749 vV(1,2) = cov[4]; vV(2,1) = cov[4];
750 vV(2,2) = cov[5];
751
752 TMatrixD sumWi(TMatrixD::kInverted,vV);
753 TMatrixD sumWiri(sumWi,TMatrixD::kMult,rv);
754
755 Int_t nUsedTrks = inVtx->GetNIndices();
756 Double_t chi2 = inVtx->GetChi2();
757
758 AliExternalTrackParam *track = 0;
759 Int_t ntrks = (Int_t)trkArray->GetEntriesFast();
760 for(Int_t i=0;i<ntrks;i++) {
761 track = (AliExternalTrackParam*)trkArray->At(i);
762 if(!inVtx->UsesTrack(id[i])) {
763 printf("track %d was not used in vertex fit",id[i]);
764 continue;
765 }
766 Double_t alpha = track->GetAlpha();
767 Double_t xl = diamondxy[0]*TMath::Cos(alpha)+diamondxy[1]*TMath::Sin(alpha);
768 track->PropagateTo(xl,GetFieldkG());
769 // vector of track global coordinates
770 TMatrixD ri(3,1);
771 // covariance matrix of ri
772 TMatrixD wWi(3,3);
773
774 // get space point from track
775 if(!TrackToPoint(track,ri,wWi)) continue;
776
777 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
778
779 sumWi -= wWi;
780 sumWiri -= wWiri;
781
782 // track contribution to chi2
783 TMatrixD deltar = rv; deltar -= ri;
784 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
785 Double_t chi2i = deltar(0,0)*wWideltar(0,0)+
786 deltar(1,0)*wWideltar(1,0)+
787 deltar(2,0)*wWideltar(2,0);
788 // remove from total chi2
789 chi2 -= chi2i;
790
791 nUsedTrks--;
792 if(nUsedTrks<2) {
793 printf("Trying to remove too many tracks!");
794 return 0x0;
795 }
796 }
797
798 TMatrixD rvnew(3,1);
799 TMatrixD vVnew(3,3);
800
801 // new inverted of weights matrix
802 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
803 vVnew = invsumWi;
804 // new position of primary vertex
805 rvnew.Mult(vVnew,sumWiri);
806
807 Double_t position[3];
808 position[0] = rvnew(0,0);
809 position[1] = rvnew(1,0);
810 position[2] = rvnew(2,0);
811 cov[0] = vVnew(0,0);
812 cov[1] = vVnew(0,1);
813 cov[2] = vVnew(1,1);
814 cov[3] = vVnew(0,2);
815 cov[4] = vVnew(1,2);
816 cov[5] = vVnew(2,2);
817
818 // store data in the vertex object
819 AliESDVertex *outVtx = new AliESDVertex(position,cov,chi2,nUsedTrks+1); // the +1 is for the constraint
820 outVtx->SetTitle(inVtx->GetTitle());
821 UShort_t *inindices = inVtx->GetIndices();
822 Int_t nIndices = nUsedTrks;
823 UShort_t *outindices = new UShort_t[nIndices];
824 Int_t j=0;
825 for(Int_t k=0; k<inVtx->GetNIndices(); k++) {
826 Bool_t copyindex=kTRUE;
827 for(Int_t l=0; l<ntrks; l++) {
828 if(inindices[k]==id[l]) copyindex=kFALSE;
829 }
830 if(copyindex) {
831 outindices[j] = inindices[k]; j++;
832 }
833 }
834 outVtx->SetIndices(nIndices,outindices);
835 if (outindices) delete [] outindices;
836
837 /*
838 printf("Vertex before removing tracks:");
839 inVtx->PrintStatus();
840 inVtx->PrintIndices();
841 printf("Vertex after removing tracks:");
842 outVtx->PrintStatus();
843 outVtx->PrintIndices();
844 */
845
846 return outVtx;
847}
848//---------------------------------------------------------------------------
849AliESDVertex* AliVertexerTracks::RemoveConstraintFromVertex(AliESDVertex *inVtx,
850 Float_t *diamondxyz,
851 Float_t *diamondcov) const
852{
853//
854// Removes diamond constraint from fit of inVtx
855//
856
857 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraint")) {
858 printf("ERROR: primary vertex has no constraint: cannot remove it\n");
859 return 0x0;
860 }
861 if(inVtx->GetNContributors()<3) {
862 printf("ERROR: primary vertex has less than 2 tracks: cannot remove contraint\n");
863 return 0x0;
864 }
865
866 // diamond constraint
867 TMatrixD vVb(3,3);
868 vVb(0,0) = diamondcov[0];
869 vVb(0,1) = diamondcov[1];
870 vVb(0,2) = 0.;
871 vVb(1,0) = diamondcov[1];
872 vVb(1,1) = diamondcov[2];
873 vVb(1,2) = 0.;
874 vVb(2,0) = 0.;
875 vVb(2,1) = 0.;
876 vVb(2,2) = diamondcov[5];
877 TMatrixD vVbInv(TMatrixD::kInverted,vVb);
878 TMatrixD rb(3,1);
879 rb(0,0) = diamondxyz[0];
880 rb(1,0) = diamondxyz[1];
881 rb(2,0) = diamondxyz[2];
882 TMatrixD vVbInvrb(vVbInv,TMatrixD::kMult,rb);
883
884 // input vertex
885 TMatrixD rv(3,1);
886 rv(0,0) = inVtx->GetXv();
887 rv(1,0) = inVtx->GetYv();
888 rv(2,0) = inVtx->GetZv();
889 TMatrixD vV(3,3);
890 Double_t cov[6];
891 inVtx->GetCovMatrix(cov);
892 vV(0,0) = cov[0];
893 vV(0,1) = cov[1]; vV(1,0) = cov[1];
894 vV(1,1) = cov[2];
895 vV(0,2) = cov[3]; vV(2,0) = cov[3];
896 vV(1,2) = cov[4]; vV(2,1) = cov[4];
897 vV(2,2) = cov[5];
898 TMatrixD vVInv(TMatrixD::kInverted,vV);
899 TMatrixD vVInvrv(vVInv,TMatrixD::kMult,rv);
900
901
902 TMatrixD sumWi = vVInv - vVbInv;
903
904
905 TMatrixD sumWiri = vVInvrv - vVbInvrb;
906
907 TMatrixD rvnew(3,1);
908 TMatrixD vVnew(3,3);
909
910 // new inverted of weights matrix
911 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
912 vVnew = invsumWi;
913 // new position of primary vertex
914 rvnew.Mult(vVnew,sumWiri);
915
916 Double_t position[3];
917 position[0] = rvnew(0,0);
918 position[1] = rvnew(1,0);
919 position[2] = rvnew(2,0);
920 cov[0] = vVnew(0,0);
921 cov[1] = vVnew(0,1);
922 cov[2] = vVnew(1,1);
923 cov[3] = vVnew(0,2);
924 cov[4] = vVnew(1,2);
925 cov[5] = vVnew(2,2);
926
927
928 Double_t chi2 = inVtx->GetChi2();
929
930 // diamond constribution to chi2
931 TMatrixD deltar = rv; deltar -= rb;
932 TMatrixD vVbInvdeltar(vVbInv,TMatrixD::kMult,deltar);
933 Double_t chi2b = deltar(0,0)*vVbInvdeltar(0,0)+
934 deltar(1,0)*vVbInvdeltar(1,0)+
935 deltar(2,0)*vVbInvdeltar(2,0);
936 // remove from total chi2
937 chi2 -= chi2b;
938
939 // store data in the vertex object
940 AliESDVertex *outVtx = new AliESDVertex(position,cov,chi2,inVtx->GetNContributors()-1);
941 outVtx->SetTitle("VertexerTracksNoConstraint");
942 UShort_t *inindices = inVtx->GetIndices();
943 Int_t nIndices = inVtx->GetNIndices();
944 outVtx->SetIndices(nIndices,inindices);
945
946 return outVtx;
947}
948//---------------------------------------------------------------------------
949void AliVertexerTracks::SetCuts(Double_t *cuts)
950{
951//
952// Cut values
953//
954 SetDCAcut(cuts[0]);
955 SetDCAcutIter0(cuts[1]);
956 SetMaxd0z0(cuts[2]);
957 if(fMode==0 && cuts[3]<0) SetITSrefitNotRequired();
958 SetMinClusters((Int_t)(TMath::Abs(cuts[3])));
959 SetMinTracks((Int_t)(cuts[4]));
960 SetNSigmad0(cuts[5]);
961 SetMinDetFitter(cuts[6]);
962 SetMaxTgl(cuts[7]);
963 SetFiducialRZ(cuts[8],cuts[9]);
964 fAlgo=(Int_t)(cuts[10]);
965 fAlgoIter0=(Int_t)(cuts[11]);
966
967 return;
968}
969//---------------------------------------------------------------------------
970void AliVertexerTracks::SetITSMode(Double_t dcacut,
971 Double_t dcacutIter0,
972 Double_t maxd0z0,
973 Int_t minCls,
974 Int_t mintrks,
975 Double_t nsigma,
976 Double_t mindetfitter,
977 Double_t maxtgl,
978 Double_t fidR,
979 Double_t fidZ,
980 Int_t finderAlgo,
981 Int_t finderAlgoIter0)
982{
983//
984// Cut values for ITS mode
985//
986 fMode = 0;
987 if(minCls>0) {
988 SetITSrefitRequired();
989 } else {
990 SetITSrefitNotRequired();
991 }
992 SetDCAcut(dcacut);
993 SetDCAcutIter0(dcacutIter0);
994 SetMaxd0z0(maxd0z0);
995 SetMinClusters(TMath::Abs(minCls));
996 SetMinTracks(mintrks);
997 SetNSigmad0(nsigma);
998 SetMinDetFitter(mindetfitter);
999 SetMaxTgl(maxtgl);
1000 SetFiducialRZ(fidR,fidZ);
1001 fAlgo=finderAlgo;
1002 fAlgoIter0=finderAlgoIter0;
1003
1004 return;
1005}
1006//---------------------------------------------------------------------------
1007void AliVertexerTracks::SetTPCMode(Double_t dcacut,
1008 Double_t dcacutIter0,
1009 Double_t maxd0z0,
1010 Int_t minCls,
1011 Int_t mintrks,
1012 Double_t nsigma,
1013 Double_t mindetfitter,
1014 Double_t maxtgl,
1015 Double_t fidR,
1016 Double_t fidZ,
1017 Int_t finderAlgo,
1018 Int_t finderAlgoIter0)
1019{
1020//
1021// Cut values for TPC mode
1022//
1023 fMode = 1;
1024 SetITSrefitNotRequired();
1025 SetDCAcut(dcacut);
1026 SetDCAcutIter0(dcacutIter0);
1027 SetMaxd0z0(maxd0z0);
1028 SetMinClusters(minCls);
1029 SetMinTracks(mintrks);
1030 SetNSigmad0(nsigma);
1031 SetMinDetFitter(mindetfitter);
1032 SetMaxTgl(maxtgl);
1033 SetFiducialRZ(fidR,fidZ);
1034 fAlgo=finderAlgo;
1035 fAlgoIter0=finderAlgoIter0;
1036
1037 return;
1038}
1039//---------------------------------------------------------------------------
1040void AliVertexerTracks::SetSkipTracks(Int_t n,const Int_t *skipped)
1041{
1042//
1043// Mark the tracks not to be used in the vertex reconstruction.
1044// Tracks are identified by AliESDtrack::GetID()
1045//
1046 fNTrksToSkip = n; fTrksToSkip = new Int_t[n];
1047 for(Int_t i=0;i<n;i++) fTrksToSkip[i] = skipped[i];
1048 return;
1049}
1050//---------------------------------------------------------------------------
1051void AliVertexerTracks::SetVtxStart(AliESDVertex *vtx)
1052{
1053//
1054// Set initial vertex knowledge
1055//
1056 vtx->GetXYZ(fNominalPos);
1057 vtx->GetCovMatrix(fNominalCov);
1058 SetConstraintOn();
1059 return;
1060}
1061//---------------------------------------------------------------------------
1062void AliVertexerTracks::StrLinVertexFinderMinDist(Int_t optUseWeights)
1063{
1064 AliExternalTrackParam *track1;
1065 const Int_t knacc = (Int_t)fTrkArraySel.GetEntriesFast();
1066 AliStrLine **linarray = new AliStrLine* [knacc];
1067 for(Int_t i=0; i<knacc; i++){
1068 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
1069 Double_t alpha=track1->GetAlpha();
1070 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1071 Double_t pos[3],dir[3],sigmasq[3];
1072 track1->GetXYZAt(mindist,GetFieldkG(),pos);
1073 track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
1074 sigmasq[0]=TMath::Sin(alpha)*TMath::Sin(alpha)*track1->GetSigmaY2();
1075 sigmasq[1]=TMath::Cos(alpha)*TMath::Cos(alpha)*track1->GetSigmaY2();
1076 sigmasq[2]=track1->GetSigmaZ2();
1077 TMatrixD ri(3,1);
1078 TMatrixD wWi(3,3);
1079 if(!TrackToPoint(track1,ri,wWi)) {optUseWeights=kFALSE;printf("WARNING\n");}
1080 Double_t wmat[9];
1081 Int_t iel=0;
1082 for(Int_t ia=0;ia<3;ia++){
1083 for(Int_t ib=0;ib<3;ib++){
1084 wmat[iel]=wWi(ia,ib);
1085 iel++;
1086 }
1087 }
1088 linarray[i] = new AliStrLine(pos,sigmasq,wmat,dir);
1089 }
1090 fVert=TrackletVertexFinder(linarray,knacc,optUseWeights);
1091 for(Int_t i=0; i<knacc; i++) delete linarray[i];
1092 delete [] linarray;
1093}
1094//---------------------------------------------------------------------------
1095AliESDVertex AliVertexerTracks::TrackletVertexFinder(const TClonesArray *lines, Int_t optUseWeights)
1096{
1097 // Calculate the point at minimum distance to prepared tracks (TClonesArray)
1098 const Int_t knacc = (Int_t)lines->GetEntriesFast();
1099 AliStrLine** lines2 = new AliStrLine* [knacc];
1100 for(Int_t i=0; i<knacc; i++){
1101 lines2[i]= (AliStrLine*)lines->At(i);
1102 }
1103 AliESDVertex vert = TrackletVertexFinder(lines2,knacc,optUseWeights);
1104 delete [] lines2;
1105 return vert;
1106}
1107
1108//---------------------------------------------------------------------------
1109AliESDVertex AliVertexerTracks::TrackletVertexFinder(AliStrLine **lines, const Int_t knacc, Int_t optUseWeights)
1110{
1111 // Calculate the point at minimum distance to prepared tracks (array of AliStrLine)
1112
1113 Double_t initPos[3]={0.,0.,0.};
1114
1115 Double_t (*vectP0)[3]=new Double_t [knacc][3];
1116 Double_t (*vectP1)[3]=new Double_t [knacc][3];
1117
1118 Double_t sum[3][3];
1119 Double_t dsum[3]={0,0,0};
1120 TMatrixD sumWi(3,3);
1121 for(Int_t i=0;i<3;i++){
1122 for(Int_t j=0;j<3;j++){
1123 sum[i][j]=0;
1124 sumWi(i,j)=0.;
1125 }
1126 }
1127
1128 for(Int_t i=0; i<knacc; i++){
1129 AliStrLine *line1 = lines[i];
1130 Double_t p0[3],cd[3],sigmasq[3];
1131 Double_t wmat[9];
1132 if(!line1) printf("ERROR %d %d\n",i,knacc);
1133 line1->GetP0(p0);
1134 line1->GetCd(cd);
1135 line1->GetSigma2P0(sigmasq);
1136 line1->GetWMatrix(wmat);
1137 TMatrixD wWi(3,3);
1138 Int_t iel=0;
1139 for(Int_t ia=0;ia<3;ia++){
1140 for(Int_t ib=0;ib<3;ib++){
1141 wWi(ia,ib)=wmat[iel];
1142 iel++;
1143 }
1144 }
1145
1146 sumWi+=wWi;
1147
1148 Double_t p1[3]={p0[0]+cd[0],p0[1]+cd[1],p0[2]+cd[2]};
1149 vectP0[i][0]=p0[0];
1150 vectP0[i][1]=p0[1];
1151 vectP0[i][2]=p0[2];
1152 vectP1[i][0]=p1[0];
1153 vectP1[i][1]=p1[1];
1154 vectP1[i][2]=p1[2];
1155
1156 Double_t matr[3][3];
1157 Double_t dknow[3];
1158 if(optUseWeights==0)GetStrLinDerivMatrix(p0,p1,matr,dknow);
1159 else GetStrLinDerivMatrix(p0,p1,sigmasq,matr,dknow);
1160
1161
1162 for(Int_t iii=0;iii<3;iii++){
1163 dsum[iii]+=dknow[iii];
1164 for(Int_t lj=0;lj<3;lj++) sum[iii][lj]+=matr[iii][lj];
1165 }
1166 }
1167
1168 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
1169 Double_t covmatrix[6];
1170 covmatrix[0] = invsumWi(0,0);
1171 covmatrix[1] = invsumWi(0,1);
1172 covmatrix[2] = invsumWi(1,1);
1173 covmatrix[3] = invsumWi(0,2);
1174 covmatrix[4] = invsumWi(1,2);
1175 covmatrix[5] = invsumWi(2,2);
1176
1177 Double_t vett[3][3];
1178 Double_t det=GetDeterminant3X3(sum);
1179 Double_t sigma=0;
1180
1181 if(TMath::Abs(det) > kAlmost0){
1182 for(Int_t zz=0;zz<3;zz++){
1183 for(Int_t ww=0;ww<3;ww++){
1184 for(Int_t kk=0;kk<3;kk++) vett[ww][kk]=sum[ww][kk];
1185 }
1186 for(Int_t kk=0;kk<3;kk++) vett[kk][zz]=dsum[kk];
1187 initPos[zz]=GetDeterminant3X3(vett)/det;
1188 }
1189
1190
1191 for(Int_t i=0; i<knacc; i++){
1192 Double_t p0[3]={0,0,0},p1[3]={0,0,0};
1193 for(Int_t ii=0;ii<3;ii++){
1194 p0[ii]=vectP0[i][ii];
1195 p1[ii]=vectP1[i][ii];
1196 }
1197 sigma+=GetStrLinMinDist(p0,p1,initPos);
1198 }
1199
1200 if(sigma>0.) {sigma=TMath::Sqrt(sigma);}else{sigma=999;}
1201 }else{
1202 sigma=999;
1203 }
1204 AliESDVertex theVert(initPos,covmatrix,99999.,knacc);
1205 theVert.SetDispersion(sigma);
1206 delete [] vectP0;
1207 delete [] vectP1;
1208 return theVert;
1209}
1210
1211//---------------------------------------------------------------------------
1212Bool_t AliVertexerTracks::TrackToPoint(AliExternalTrackParam *t,
1213 TMatrixD &ri,TMatrixD &wWi,
1214 Bool_t uUi3by3) const
1215{
1216//
1217// Extract from the AliExternalTrackParam the global coordinates ri and covariance matrix
1218// wWi of the space point that it represents (to be used in VertexFitter())
1219//
1220
1221
1222 Double_t rotAngle = t->GetAlpha();
1223 if(rotAngle<0.) rotAngle += 2.*TMath::Pi();
1224 Double_t cosRot = TMath::Cos(rotAngle);
1225 Double_t sinRot = TMath::Sin(rotAngle);
1226
1227 ri(0,0) = t->GetX()*cosRot-t->GetY()*sinRot;
1228 ri(1,0) = t->GetX()*sinRot+t->GetY()*cosRot;
1229 ri(2,0) = t->GetZ();
1230
1231
1232
1233 if(!uUi3by3) {
1234 // matrix to go from global (x,y,z) to local (y,z);
1235 TMatrixD qQi(2,3);
1236 qQi(0,0) = -sinRot;
1237 qQi(0,1) = cosRot;
1238 qQi(0,2) = 0.;
1239 qQi(1,0) = 0.;
1240 qQi(1,1) = 0.;
1241 qQi(1,2) = 1.;
1242
1243 // covariance matrix of local (y,z) - inverted
1244 TMatrixD uUi(2,2);
1245 uUi(0,0) = t->GetSigmaY2();
1246 uUi(0,1) = t->GetSigmaZY();
1247 uUi(1,0) = t->GetSigmaZY();
1248 uUi(1,1) = t->GetSigmaZ2();
1249 //printf(" Ui :");
1250 //printf(" %f %f",uUi(0,0),uUi(0,1));
1251 //printf(" %f %f",uUi(1,0),uUi(1,1));
1252
1253 if(uUi.Determinant() <= 0.) return kFALSE;
1254 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
1255
1256 // weights matrix: wWi = qQiT * uUiInv * qQi
1257 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
1258 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
1259 wWi = m;
1260 } else {
1261 if(fVert.GetNContributors()<1) AliFatal("Vertex from finder is empty");
1262 // matrix to go from global (x,y,z) to local (x,y,z);
1263 TMatrixD qQi(3,3);
1264 qQi(0,0) = cosRot;
1265 qQi(0,1) = sinRot;
1266 qQi(0,2) = 0.;
1267 qQi(1,0) = -sinRot;
1268 qQi(1,1) = cosRot;
1269 qQi(1,2) = 0.;
1270 qQi(2,0) = 0.;
1271 qQi(2,1) = 0.;
1272 qQi(2,2) = 1.;
1273
1274 // covariance of fVert along the track
1275 Double_t p[3],pt,ptot;
1276 t->GetPxPyPz(p);
1277 pt = TMath::Sqrt(p[0]*p[0]+p[1]*p[1]);
1278 ptot = TMath::Sqrt(pt*pt+p[2]*p[2]);
1279 Double_t cphi = p[0]/pt; //cos(phi)=px/pt
1280 Double_t sphi = p[1]/pt; //sin(phi)=py/pt
1281 Double_t clambda = pt/ptot; //cos(lambda)=pt/ptot
1282 Double_t slambda = p[2]/ptot; //sin(lambda)=pz/ptot
1283 Double_t covfVert[6];
1284 fVert.GetCovMatrix(covfVert);
1285 Double_t covfVertalongt =
1286 covfVert[0]*cphi*cphi*clambda*clambda
1287 +covfVert[1]*2.*cphi*sphi*clambda*clambda
1288 +covfVert[3]*2.*cphi*clambda*slambda
1289 +covfVert[2]*sphi*sphi*clambda*clambda
1290 +covfVert[4]*2.*sphi*clambda*slambda
1291 +covfVert[5]*slambda*slambda;
1292 // covariance matrix of local (x,y,z) - inverted
1293 TMatrixD uUi(3,3);
1294 uUi(0,0) = covfVertalongt * fnSigmaForUi00 * fnSigmaForUi00;
1295 AliDebug(1,Form("=====> sqrtUi00 cm %f",TMath::Sqrt(uUi(0,0))));
1296 uUi(0,1) = 0.;
1297 uUi(0,2) = 0.;
1298 uUi(1,0) = 0.;
1299 uUi(1,1) = t->GetSigmaY2();
1300 uUi(1,2) = t->GetSigmaZY();
1301 uUi(2,0) = 0.;
1302 uUi(2,1) = t->GetSigmaZY();
1303 uUi(2,2) = t->GetSigmaZ2();
1304 //printf(" Ui :\n");
1305 //printf(" %f %f\n",uUi(0,0),uUi(0,1));
1306 //printf(" %f %f\n",uUi(1,0),uUi(1,1));
1307
1308 if(uUi.Determinant() <= 0.) return kFALSE;
1309 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
1310
1311 // weights matrix: wWi = qQiT * uUiInv * qQi
1312 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
1313 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
1314 wWi = m;
1315 }
1316
1317
1318 return kTRUE;
1319}
1320//---------------------------------------------------------------------------
1321void AliVertexerTracks::TooFewTracks()
1322{
1323//
1324// When the number of tracks is < fMinTracks,
1325// deal with vertices not found and prepare to exit
1326//
1327 AliDebug(1,"TooFewTracks");
1328
1329 Double_t pos[3],err[3];
1330 pos[0] = fNominalPos[0];
1331 err[0] = TMath::Sqrt(fNominalCov[0]);
1332 pos[1] = fNominalPos[1];
1333 err[1] = TMath::Sqrt(fNominalCov[2]);
1334 pos[2] = fNominalPos[2];
1335 err[2] = TMath::Sqrt(fNominalCov[5]);
1336 Int_t ncontr = (err[0]>1. ? -1 : -3);
1337 if(fCurrentVertex) { delete fCurrentVertex; fCurrentVertex=0; }
1338 fCurrentVertex = new AliESDVertex(pos,err);
1339 fCurrentVertex->SetNContributors(ncontr);
1340
1341 if(fConstraint) {
1342 fCurrentVertex->SetTitle("VertexerTracksWithConstraint");
1343 } else {
1344 fCurrentVertex->SetTitle("VertexerTracksNoConstraint");
1345 }
1346
1347 if(!fTrkArraySel.IsEmpty()) fTrkArraySel.Delete();
1348 if(fIdSel) {delete [] fIdSel; fIdSel=NULL;}
1349 if(fTrksToSkip) {delete [] fTrksToSkip; fTrksToSkip=NULL;}
1350
1351 return;
1352}
1353//---------------------------------------------------------------------------
1354void AliVertexerTracks::VertexFinder(Int_t optUseWeights)
1355{
1356
1357 // Get estimate of vertex position in (x,y) from tracks DCA
1358
1359 Double_t initPos[3];
1360 initPos[2] = 0.;
1361 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
1362 Int_t nacc = (Int_t)fTrkArraySel.GetEntriesFast();
1363 Double_t aver[3]={0.,0.,0.};
1364 Double_t aversq[3]={0.,0.,0.};
1365 Double_t sigmasq[3]={0.,0.,0.};
1366 Double_t sigma=0;
1367 Int_t ncombi = 0;
1368 AliExternalTrackParam *track1;
1369 AliExternalTrackParam *track2;
1370 Double_t pos[3],dir[3];
1371 Double_t alpha,mindist;
1372
1373 for(Int_t i=0; i<nacc; i++){
1374 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
1375 alpha=track1->GetAlpha();
1376 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1377 track1->GetXYZAt(mindist,GetFieldkG(),pos);
1378 track1->GetPxPyPzAt(mindist,GetFieldkG(),dir);
1379 AliStrLine *line1 = new AliStrLine(pos,dir);
1380
1381 // AliStrLine *line1 = new AliStrLine();
1382 // track1->ApproximateHelixWithLine(mindist,GetFieldkG(),line1);
1383
1384 for(Int_t j=i+1; j<nacc; j++){
1385 track2 = (AliExternalTrackParam*)fTrkArraySel.At(j);
1386 alpha=track2->GetAlpha();
1387 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1388 track2->GetXYZAt(mindist,GetFieldkG(),pos);
1389 track2->GetPxPyPzAt(mindist,GetFieldkG(),dir);
1390 AliStrLine *line2 = new AliStrLine(pos,dir);
1391 // AliStrLine *line2 = new AliStrLine();
1392 // track2->ApproximateHelixWithLine(mindist,GetFieldkG(),line2);
1393 Double_t distCA=line2->GetDCA(line1);
1394 //printf("%d %d %f\n",i,j,distCA);
1395 if(fDCAcut<=0 || (fDCAcut>0&&distCA<fDCAcut)){
1396 Double_t pnt1[3],pnt2[3],crosspoint[3];
1397
1398 if(optUseWeights<=0){
1399 Int_t retcode = line2->Cross(line1,crosspoint);
1400 if(retcode>=0){
1401 ncombi++;
1402 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
1403 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1404 }
1405 }
1406 if(optUseWeights>0){
1407 Int_t retcode = line1->CrossPoints(line2,pnt1,pnt2);
1408 if(retcode>=0){
1409 Double_t cs, sn;
1410 alpha=track1->GetAlpha();
1411 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
1412 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
1413 alpha=track2->GetAlpha();
1414 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
1415 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
1416 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
1417 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
1418 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
1419 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
1420 crosspoint[0]=wx1*pnt1[0] + wx2*pnt2[0];
1421 crosspoint[1]=wy1*pnt1[1] + wy2*pnt2[1];
1422 crosspoint[2]=wz1*pnt1[2] + wz2*pnt2[2];
1423
1424 ncombi++;
1425 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
1426 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1427 }
1428 }
1429 }
1430 delete line2;
1431 }
1432 delete line1;
1433 }
1434 if(ncombi>0){
1435 for(Int_t jj=0;jj<3;jj++){
1436 initPos[jj] = aver[jj]/ncombi;
1437 //printf("%f\n",initPos[jj]);
1438 aversq[jj]/=ncombi;
1439 sigmasq[jj]=aversq[jj]-initPos[jj]*initPos[jj];
1440 sigma+=sigmasq[jj];
1441 }
1442 sigma=TMath::Sqrt(TMath::Abs(sigma));
1443 }
1444 else {
1445 Warning("VertexFinder","Finder did not succed");
1446 sigma=999;
1447 }
1448 fVert.SetXYZ(initPos);
1449 fVert.SetDispersion(sigma);
1450 fVert.SetNContributors(ncombi);
1451}
1452//---------------------------------------------------------------------------
1453void AliVertexerTracks::VertexFitter()
1454{
1455//
1456// The optimal estimate of the vertex position is given by a "weighted
1457// average of tracks positions".
1458// Original method: V. Karimaki, CMS Note 97/0051
1459//
1460 Bool_t useConstraint = fConstraint;
1461 Double_t initPos[3];
1462 if(!fOnlyFitter) {
1463 fVert.GetXYZ(initPos);
1464 } else {
1465 initPos[0]=fNominalPos[0];
1466 initPos[1]=fNominalPos[1];
1467 initPos[2]=fNominalPos[2];
1468 }
1469
1470 Int_t nTrksSel = (Int_t)fTrkArraySel.GetEntries();
1471 if(nTrksSel==1) useConstraint=kTRUE;
1472 AliDebug(1,"--- VertexFitter(): start");
1473 AliDebug(1,Form(" Number of tracks in array: %d\n",nTrksSel));
1474 AliDebug(1,Form(" Minimum # tracks required in fit: %d\n",fMinTracks));
1475 AliDebug(1,Form(" Vertex position after finder: %f,%f,%f\n",initPos[0],initPos[1],initPos[2]));
1476 if(useConstraint) AliDebug(1,Form(" This vertex will be used in fit: (%f+-%f,%f+-%f)\n",fNominalPos[0],TMath::Sqrt(fNominalCov[0]),fNominalPos[1],TMath::Sqrt(fNominalCov[2])));
1477
1478 // special treatment for few-tracks fits (e.g. secondary vertices)
1479 Bool_t uUi3by3 = kFALSE; if(nTrksSel<5 && !useConstraint) uUi3by3 = kTRUE;
1480
1481 Int_t i,j,k,step=0;
1482 TMatrixD rv(3,1);
1483 TMatrixD vV(3,3);
1484 rv(0,0) = initPos[0];
1485 rv(1,0) = initPos[1];
1486 rv(2,0) = 0.;
1487 Double_t xlStart,alpha;
1488 Int_t nTrksUsed;
1489 Double_t chi2,chi2i,chi2b;
1490 AliExternalTrackParam *t = 0;
1491 Int_t failed = 0;
1492
1493 // initial vertex covariance matrix
1494 TMatrixD vVb(3,3);
1495 vVb(0,0) = fNominalCov[0];
1496 vVb(0,1) = fNominalCov[1];
1497 vVb(0,2) = 0.;
1498 vVb(1,0) = fNominalCov[1];
1499 vVb(1,1) = fNominalCov[2];
1500 vVb(1,2) = 0.;
1501 vVb(2,0) = 0.;
1502 vVb(2,1) = 0.;
1503 vVb(2,2) = fNominalCov[5];
1504 TMatrixD vVbInv(TMatrixD::kInverted,vVb);
1505 TMatrixD rb(3,1);
1506 rb(0,0) = fNominalPos[0];
1507 rb(1,0) = fNominalPos[1];
1508 rb(2,0) = fNominalPos[2];
1509 TMatrixD vVbInvrb(vVbInv,TMatrixD::kMult,rb);
1510
1511
1512 // 2 steps:
1513 // 1st - estimate of vtx using all tracks
1514 // 2nd - estimate of global chi2
1515 for(step=0; step<2; step++) {
1516 AliDebug(1,Form(" step = %d\n",step));
1517 chi2 = 0.;
1518 nTrksUsed = 0;
1519
1520 if(step==1) { initPos[0]=rv(0,0); initPos[0]=rv(1,0); }
1521
1522 TMatrixD sumWiri(3,1);
1523 TMatrixD sumWi(3,3);
1524 for(i=0; i<3; i++) {
1525 sumWiri(i,0) = 0.;
1526 for(j=0; j<3; j++) sumWi(j,i) = 0.;
1527 }
1528
1529 // mean vertex constraint
1530 if(useConstraint) {
1531 for(i=0;i<3;i++) {
1532 sumWiri(i,0) += vVbInvrb(i,0);
1533 for(k=0;k<3;k++) sumWi(i,k) += vVbInv(i,k);
1534 }
1535 // chi2
1536 TMatrixD deltar = rv; deltar -= rb;
1537 TMatrixD vVbInvdeltar(vVbInv,TMatrixD::kMult,deltar);
1538 chi2b = deltar(0,0)*vVbInvdeltar(0,0)+
1539 deltar(1,0)*vVbInvdeltar(1,0)+
1540 deltar(2,0)*vVbInvdeltar(2,0);
1541 chi2 += chi2b;
1542 }
1543
1544 // loop on tracks
1545 for(k=0; k<nTrksSel; k++) {
1546 // get track from track array
1547 t = (AliExternalTrackParam*)fTrkArraySel.At(k);
1548 alpha = t->GetAlpha();
1549 xlStart = initPos[0]*TMath::Cos(alpha)+initPos[1]*TMath::Sin(alpha);
1550 // to vtxSeed (from finder)
1551 t->PropagateTo(xlStart,GetFieldkG());
1552
1553 // vector of track global coordinates
1554 TMatrixD ri(3,1);
1555 // covariance matrix of ri
1556 TMatrixD wWi(3,3);
1557
1558 // get space point from track
1559 if(!TrackToPoint(t,ri,wWi,uUi3by3)) continue;
1560 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
1561
1562 // track chi2
1563 TMatrixD deltar = rv; deltar -= ri;
1564 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
1565 chi2i = deltar(0,0)*wWideltar(0,0)+
1566 deltar(1,0)*wWideltar(1,0)+
1567 deltar(2,0)*wWideltar(2,0);
1568
1569 // add to total chi2
1570 chi2 += chi2i;
1571
1572 sumWiri += wWiri;
1573 sumWi += wWi;
1574
1575 nTrksUsed++;
1576 } // end loop on tracks
1577
1578 if(nTrksUsed < fMinTracks) {
1579 failed=1;
1580 continue;
1581 }
1582
1583 Double_t determinant = sumWi.Determinant();
1584 if(determinant < fMinDetFitter) {
1585 AliDebug(1,Form("det(V) = %f (<%f)\n",determinant,fMinDetFitter));
1586 failed=1;
1587 continue;
1588 }
1589
1590 if(step==0) {
1591 // inverted of weights matrix
1592 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
1593 vV = invsumWi;
1594 // position of primary vertex
1595 rv.Mult(vV,sumWiri);
1596 }
1597 } // end loop on the 2 steps
1598
1599 if(failed) {
1600 TooFewTracks();
1601 return;
1602 }
1603
1604 Double_t position[3];
1605 position[0] = rv(0,0);
1606 position[1] = rv(1,0);
1607 position[2] = rv(2,0);
1608 Double_t covmatrix[6];
1609 covmatrix[0] = vV(0,0);
1610 covmatrix[1] = vV(0,1);
1611 covmatrix[2] = vV(1,1);
1612 covmatrix[3] = vV(0,2);
1613 covmatrix[4] = vV(1,2);
1614 covmatrix[5] = vV(2,2);
1615
1616 // for correct chi2/ndf, count constraint as additional "track"
1617 if(fConstraint) nTrksUsed++;
1618 // store data in the vertex object
1619 if(fCurrentVertex) { delete fCurrentVertex; fCurrentVertex=0; }
1620 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nTrksUsed);
1621
1622 AliDebug(1," Vertex after fit:");
1623 AliDebug(1,Form("xyz: %f %f %f; nc %d",fCurrentVertex->GetXv(),fCurrentVertex->GetYv(),fCurrentVertex->GetZv(),fCurrentVertex->GetNContributors()));
1624 AliDebug(1,"--- VertexFitter(): finish\n");
1625
1626
1627 return;
1628}
1629//----------------------------------------------------------------------------
1630AliESDVertex* AliVertexerTracks::VertexForSelectedTracks(const TObjArray *trkArray,
1631 UShort_t *id,
1632 Bool_t optUseFitter,
1633 Bool_t optPropagate,
1634 Bool_t optUseDiamondConstraint)
1635{
1636//
1637// Return vertex from tracks (AliExternalTrackParam) in array
1638//
1639 fCurrentVertex = 0;
1640 // set optUseDiamondConstraint=TRUE only if you are reconstructing the
1641 // primary vertex!
1642 if(optUseDiamondConstraint) {
1643 SetConstraintOn();
1644 } else {
1645 SetConstraintOff();
1646 }
1647
1648 // get tracks and propagate them to initial vertex position
1649 fIdSel = new UShort_t[(Int_t)trkArray->GetEntriesFast()];
1650 Int_t nTrksSel = PrepareTracks(*trkArray,id,0);
1651 if((!optUseDiamondConstraint && nTrksSel<TMath::Max(2,fMinTracks)) ||
1652 (optUseDiamondConstraint && nTrksSel<1)) {
1653 TooFewTracks();
1654 return fCurrentVertex;
1655 }
1656
1657 // vertex finder
1658 if(nTrksSel==1) {
1659 AliDebug(1,"Just one track");
1660 OneTrackVertFinder();
1661 } else {
1662 switch (fAlgo) {
1663 case 1: StrLinVertexFinderMinDist(1); break;
1664 case 2: StrLinVertexFinderMinDist(0); break;
1665 case 3: HelixVertexFinder(); break;
1666 case 4: VertexFinder(1); break;
1667 case 5: VertexFinder(0); break;
1668 default: printf("Wrong algorithm\n"); break;
1669 }
1670 }
1671 AliDebug(1," Vertex finding completed\n");
1672
1673 // vertex fitter
1674 if(optUseFitter) {
1675 VertexFitter();
1676 } else {
1677 Double_t position[3]={fVert.GetXv(),fVert.GetYv(),fVert.GetZv()};
1678 Double_t covmatrix[6];
1679 fVert.GetCovMatrix(covmatrix);
1680 Double_t chi2=99999.;
1681 Int_t nTrksUsed=fVert.GetNContributors();
1682 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nTrksUsed);
1683 }
1684 fCurrentVertex->SetDispersion(fVert.GetDispersion());
1685
1686
1687 // set indices of used tracks and propagate track to found vertex
1688 UShort_t *indices = 0;
1689 Double_t d0z0[2],covd0z0[3];
1690 AliExternalTrackParam *t = 0;
1691 if(fCurrentVertex->GetNContributors()>0) {
1692 indices = new UShort_t[fTrkArraySel.GetEntriesFast()];
1693 for(Int_t jj=0; jj<(Int_t)fTrkArraySel.GetEntriesFast(); jj++) {
1694 indices[jj] = fIdSel[jj];
1695 t = (AliExternalTrackParam*)fTrkArraySel.At(jj);
1696 if(optPropagate && optUseFitter) {
1697 if(TMath::Sqrt(fCurrentVertex->GetXv()*fCurrentVertex->GetXv()+fCurrentVertex->GetYv()*fCurrentVertex->GetYv())<3.) {
1698 t->PropagateToDCA(fCurrentVertex,GetFieldkG(),100.,d0z0,covd0z0);
1699 AliDebug(1,Form("Track %d propagated to found vertex",jj));
1700 } else {
1701 AliWarning("Found vertex outside beam pipe!");
1702 }
1703 }
1704 }
1705 fCurrentVertex->SetIndices(fCurrentVertex->GetNContributors(),indices);
1706 }
1707
1708 // clean up
1709 if (indices) {delete [] indices; indices=NULL;}
1710 delete [] fIdSel; fIdSel=NULL;
1711 fTrkArraySel.Delete();
1712
1713 return fCurrentVertex;
1714}
1715//----------------------------------------------------------------------------
1716AliESDVertex* AliVertexerTracks::VertexForSelectedESDTracks(TObjArray *trkArray,
1717 Bool_t optUseFitter,
1718 Bool_t optPropagate,
1719 Bool_t optUseDiamondConstraint)
1720
1721{
1722//
1723// Return vertex from array of ESD tracks
1724//
1725
1726 Int_t nTrks = (Int_t)trkArray->GetEntriesFast();
1727 UShort_t *id = new UShort_t[nTrks];
1728
1729 AliESDtrack *esdt = 0;
1730 for(Int_t i=0; i<nTrks; i++){
1731 esdt = (AliESDtrack*)trkArray->At(i);
1732 id[i] = (UShort_t)esdt->GetID();
1733 }
1734
1735 VertexForSelectedTracks(trkArray,id,optUseFitter,optPropagate,optUseDiamondConstraint);
1736
1737 delete [] id; id=NULL;
1738
1739 return fCurrentVertex;
1740}
1741//--------------------------------------------------------------------------