]> git.uio.no Git - u/mrichter/AliRoot.git/blame - STEER/AliVertexerTracks.cxx
git://git.uio.no / u / mrichter / AliRoot.git / blame
? search:
summary | shortlog | log | commit | commitdiff | tree
blob | blame (incremental) | history | HEAD
introducing SDD, SSD layer misal (Andrea Dainese)
[u/mrichter/AliRoot.git] / STEER / AliVertexerTracks.cxx
CommitLineData
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//-----------------------------------------------------------------
6d8df534 17// Implementation of the vertexer from tracks
2d57349e 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:
6d8df534 25// F.Prino, Torino, prino@to.infn.it
2d57349e 26//-----------------------------------------------------------------
27
28//---- Root headers --------
a7ede274 29#include <TSystem.h>
30#include <TDirectory.h>
31#include <TFile.h>
2d57349e 32#include <TTree.h>
ec1be5d5 33#include <TMatrixD.h>
2d57349e 34//---- AliRoot headers -----
35#include "AliStrLine.h"
6d8df534 36#include "AliExternalTrackParam.h"
af885e0f 37#include "AliESDEvent.h"
2d57349e 38#include "AliESDtrack.h"
6d8df534 39#include "AliVertexerTracks.h"
2d57349e 40
41ClassImp(AliVertexerTracks)
42
43
44//----------------------------------------------------------------------------
45AliVertexerTracks::AliVertexerTracks():
07680cae 46TObject(),
47fVert(),
48fCurrentVertex(0),
dc3719f3 49fFieldkG(-999.),
fee9ef0d 50fConstraint(kFALSE),
51fOnlyFitter(kFALSE),
0c69be49 52fMinTracks(1),
fe12e09c 53fMinITSClusters(5),
6d8df534 54fTrkArraySel(),
55fIdSel(0),
07680cae 56fTrksToSkip(0),
57fNTrksToSkip(0),
58fDCAcut(0),
59fAlgo(1),
fe12e09c 60fNSigma(3),
fee9ef0d 61fMaxd0z0(0.5),
50ff0bcd 62fITSrefit(kTRUE),
3b768a1d 63fnSigmaForUi00(1.5),
07680cae 64fDebug(0)
2d57349e 65{
66//
67// Default constructor
68//
3b768a1d 69 SetVtxStart();
07680cae 70 SetVtxStartSigma();
2d57349e 71 SetMinTracks();
07680cae 72 SetMinITSClusters();
73 SetNSigmad0();
fee9ef0d 74 SetMaxd0z0();
2d57349e 75}
dc3719f3 76//----------------------------------------------------------------------------
77AliVertexerTracks::AliVertexerTracks(Double_t fieldkG):
07680cae 78TObject(),
79fVert(),
80fCurrentVertex(0),
dc3719f3 81fFieldkG(-999.),
fee9ef0d 82fConstraint(kFALSE),
83fOnlyFitter(kFALSE),
0c69be49 84fMinTracks(1),
fe12e09c 85fMinITSClusters(5),
6d8df534 86fTrkArraySel(),
87fIdSel(0),
07680cae 88fTrksToSkip(0),
89fNTrksToSkip(0),
90fDCAcut(0),
91fAlgo(1),
fe12e09c 92fNSigma(3),
fee9ef0d 93fMaxd0z0(0.5),
50ff0bcd 94fITSrefit(kTRUE),
3b768a1d 95fnSigmaForUi00(1.5),
07680cae 96fDebug(0)
2d57349e 97{
98//
99// Standard constructor
100//
3b768a1d 101 SetVtxStart();
07680cae 102 SetVtxStartSigma();
2d57349e 103 SetMinTracks();
07680cae 104 SetMinITSClusters();
105 SetNSigmad0();
dc3719f3 106 SetMaxd0z0();
107 SetFieldkG(fieldkG);
2d57349e 108}
109//-----------------------------------------------------------------------------
fee9ef0d 110AliVertexerTracks::~AliVertexerTracks()
111{
2d57349e 112 // Default Destructor
eae1677e 113 // The objects pointed by the following pointer are not owned
2d57349e 114 // by this class and are not deleted
ec1be5d5 115 fCurrentVertex = 0;
146c29df 116 if(fTrksToSkip) { delete [] fTrksToSkip; fTrksToSkip=NULL; }
6d8df534 117 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
ec1be5d5 118}
c5e3e5d1 119//----------------------------------------------------------------------------
af885e0f 120AliESDVertex* AliVertexerTracks::FindPrimaryVertex(const AliESDEvent *esdEvent)
ec1be5d5 121{
c5e3e5d1 122//
ec1be5d5 123// Primary vertex for current ESD event
eae1677e 124// (Two iterations:
fee9ef0d 125// 1st with 5*fNSigma*sigma cut w.r.t. to initial vertex
126// + cut on sqrt(d0d0+z0z0) if fConstraint=kFALSE
127// 2nd with fNSigma*sigma cut w.r.t. to vertex found in 1st iteration)
07680cae 128//
129 fCurrentVertex = 0;
130
dc3719f3 131 // accept 1-track case only if constraint is available
132 if(!fConstraint && fMinTracks==1) fMinTracks=2;
133
fee9ef0d 134 // read tracks from ESD
6d8df534 135 Int_t nTrks = (Int_t)esdEvent->GetNumberOfTracks();
136 if(nTrks<1) {
137 TooFewTracks();
80d36431 138 return fCurrentVertex;
139 }
6d8df534 140 //
713e5fbf 141
a7ede274 142 TDirectory * olddir = gDirectory;
143 TFile f("VertexerTracks.root","recreate");
6d8df534 144 TObjArray trkArrayOrig(nTrks);
145 UShort_t *idOrig = new UShort_t[nTrks];
07680cae 146
6d8df534 147 Int_t nTrksOrig=0;
148 for(Int_t i=0; i<nTrks; i++) {
149 AliESDtrack *esdt = esdEvent->GetTrack(i);
eae1677e 150 // check tracks to skip
6d8df534 151 Bool_t skipThis = kFALSE;
eae1677e 152 for(Int_t j=0; j<fNTrksToSkip; j++) {
6d8df534 153 if(esdt->GetID()==fTrksToSkip[j]) {
eae1677e 154 if(fDebug) printf("skipping track: %d\n",i);
155 skipThis = kTRUE;
156 }
157 }
a7ede274 158 if(skipThis) continue;
6d8df534 159 if(fITSrefit) {
160 if(!(esdt->GetStatus()&AliESDtrack::kITSrefit)) continue;
161 // check number of clusters in ITS
162 if(esdt->GetNcls(0)<fMinITSClusters) continue;
50ff0bcd 163 }
6d8df534 164 Double_t x,p[5],cov[15];
165 esdt->GetExternalParameters(x,p);
166 esdt->GetExternalCovariance(cov);
167 AliExternalTrackParam *t = new AliExternalTrackParam(x,esdt->GetAlpha(),p,cov);
168 trkArrayOrig.AddLast(t);
169 idOrig[nTrksOrig]=(UShort_t)esdt->GetID();
170 nTrksOrig++;
07680cae 171 }
fee9ef0d 172
6d8df534 173 FindPrimaryVertex(&trkArrayOrig,idOrig);
174
175 trkArrayOrig.Delete();
176 delete [] idOrig; idOrig=NULL;
177 f.Close();
178 gSystem->Unlink("VertexerTracks.root");
179 olddir->cd();
180
181 return fCurrentVertex;
182}
183//----------------------------------------------------------------------------
184AliESDVertex* AliVertexerTracks::FindPrimaryVertex(TObjArray *trkArrayOrig,
185 UShort_t *idOrig)
186{
187//
188// Primary vertex using the AliExternalTrackParam's in the TObjArray.
189// idOrig must contain the track IDs from AliESDtrack::GetID()
190// (Two iterations:
191// 1st with 5*fNSigma*sigma cut w.r.t. to initial vertex
192// + cut on sqrt(d0d0+z0z0) if fConstraint=kFALSE
193// 2nd with fNSigma*sigma cut w.r.t. to vertex found in 1st iteration)
194//
195 fCurrentVertex = 0;
196
197 // accept 1-track case only if constraint is available
198 if(!fConstraint && fMinTracks==1) fMinTracks=2;
199
200 // read tracks from ESD
201 Int_t nTrksOrig = (Int_t)trkArrayOrig->GetEntriesFast();
202 if(nTrksOrig<=0) {
203 if(fDebug) printf("TooFewTracks\n");
204 TooFewTracks();
205 return fCurrentVertex;
206 }
207
fee9ef0d 208 // If fConstraint=kFALSE
209 // run VertexFinder(1) to get rough estimate of initVertex (x,y)
210 if(!fConstraint) {
6d8df534 211 // fill fTrkArraySel, for VertexFinder()
212 fIdSel = new UShort_t[nTrksOrig];
213 PrepareTracks(*trkArrayOrig,idOrig,0);
214 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
215 Double_t cutsave = fDCAcut;
216 fDCAcut = (fITSrefit ? 0.1 : 0.5);
fee9ef0d 217 VertexFinder(1); // using weights, cutting dca < fDCAcut
218 fDCAcut = cutsave;
fee9ef0d 219 if(fVert.GetNContributors()>0) {
220 fVert.GetXYZ(fNominalPos);
221 fNominalPos[0] = fVert.GetXv();
222 fNominalPos[1] = fVert.GetYv();
223 fNominalPos[2] = fVert.GetZv();
224 if(fDebug) printf("No mean vertex: VertexFinder gives (%f, %f, %f)\n",fNominalPos[0],fNominalPos[1],fNominalPos[2]);
225 } else {
226 fNominalPos[0] = 0.;
227 fNominalPos[1] = 0.;
228 fNominalPos[2] = 0.;
229 if(fDebug) printf("No mean vertex and VertexFinder failed\n");
0c69be49 230 }
07680cae 231 }
fee9ef0d 232
233 // TWO ITERATIONS:
234 //
235 // ITERATION 1
236 // propagate tracks to fNominalPos vertex
237 // preselect them:
238 // if(constraint) reject for |d0|>5*fNSigma*sigma w.r.t. fNominal... vertex
239 // else reject for |d0|\oplus|z0| > 5 mm w.r.t. fNominal... vertex
07680cae 240 // ITERATION 2
241 // propagate tracks to best between initVertex and fCurrentVertex
242 // preselect tracks (reject for |d0|>fNSigma*sigma w.r.t. best
243 // between initVertex and fCurrentVertex)
6d8df534 244 for(Int_t iter=1; iter<=2; iter++) {
245 if(fOnlyFitter && iter==1) continue;
246 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
247 fIdSel = new UShort_t[nTrksOrig];
248 Int_t nTrksSel = PrepareTracks(*trkArrayOrig,idOrig,iter);
249 if(fDebug) printf("N tracks selected in iteration %d: %d\n",iter,nTrksSel);
250 if(nTrksSel < fMinTracks) {
251 TooFewTracks();
fee9ef0d 252 return fCurrentVertex;
253 }
07680cae 254
fee9ef0d 255 // vertex finder
256 if(!fOnlyFitter) {
6d8df534 257 if(nTrksSel==1) {
fee9ef0d 258 if(fDebug) printf("Just one track\n");
259 OneTrackVertFinder();
6d8df534 260 } else {
fee9ef0d 261 switch (fAlgo) {
262 case 1: StrLinVertexFinderMinDist(1); break;
263 case 2: StrLinVertexFinderMinDist(0); break;
264 case 3: HelixVertexFinder(); break;
265 case 4: VertexFinder(1); break;
266 case 5: VertexFinder(0); break;
267 default: printf("Wrong algorithm\n"); break;
268 }
269 }
270 if(fDebug) printf(" Vertex finding completed\n");
0c69be49 271 }
07680cae 272
fee9ef0d 273 // vertex fitter
6d8df534 274 VertexFitter();
fee9ef0d 275 } // end loop on the two iterations
07680cae 276
fee9ef0d 277
50ff0bcd 278 // set indices of used tracks
279 UShort_t *indices = 0;
50ff0bcd 280 if(fCurrentVertex->GetNContributors()>0) {
281 indices = new UShort_t[fCurrentVertex->GetNContributors()];
6d8df534 282 for(Int_t jj=0; jj<(Int_t)fTrkArraySel.GetEntriesFast(); jj++)
283 indices[jj] = fIdSel[jj];
50ff0bcd 284 fCurrentVertex->SetIndices(fCurrentVertex->GetNContributors(),indices);
285 }
6d8df534 286 delete [] indices; indices=NULL;
287 //
fee9ef0d 288
6d8df534 289 // set vertex title
290 TString title="VertexerTracksNoConstraint";
291 if(fConstraint) {
292 title="VertexerTracksWithConstraint";
293 if(fOnlyFitter) title.Append("OnlyFitter");
294 }
295 fCurrentVertex->SetTitle(title.Data());
296 //
a7ede274 297
6d8df534 298 if(fDebug) {
299 fCurrentVertex->PrintStatus();
300 fCurrentVertex->PrintIndices();
301 }
50ff0bcd 302
6d8df534 303 // clean up
304 delete [] fIdSel; fIdSel=NULL;
305 fTrkArraySel.Delete();
146c29df 306 if(fTrksToSkip) { delete [] fTrksToSkip; fTrksToSkip=NULL; }
6d8df534 307 //
fee9ef0d 308
07680cae 309 return fCurrentVertex;
310}
50ff0bcd 311//------------------------------------------------------------------------
fee9ef0d 312Double_t AliVertexerTracks::GetDeterminant3X3(Double_t matr[][3])
313{
50ff0bcd 314 //
315 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];
316 return det;
317}
318//-------------------------------------------------------------------------
fee9ef0d 319void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t (*m)[3],Double_t *d)
320{
50ff0bcd 321 //
322 Double_t x12=p0[0]-p1[0];
323 Double_t y12=p0[1]-p1[1];
324 Double_t z12=p0[2]-p1[2];
325 Double_t kk=x12*x12+y12*y12+z12*z12;
326 m[0][0]=2-2/kk*x12*x12;
327 m[0][1]=-2/kk*x12*y12;
328 m[0][2]=-2/kk*x12*z12;
329 m[1][0]=-2/kk*x12*y12;
330 m[1][1]=2-2/kk*y12*y12;
331 m[1][2]=-2/kk*y12*z12;
332 m[2][0]=-2/kk*x12*z12;
333 m[2][1]=-2*y12*z12;
334 m[2][2]=2-2/kk*z12*z12;
335 d[0]=2*p0[0]-2/kk*p0[0]*x12*x12-2/kk*p0[2]*x12*z12-2/kk*p0[1]*x12*y12;
336 d[1]=2*p0[1]-2/kk*p0[1]*y12*y12-2/kk*p0[0]*x12*y12-2/kk*p0[2]*z12*y12;
337 d[2]=2*p0[2]-2/kk*p0[2]*z12*z12-2/kk*p0[0]*x12*z12-2/kk*p0[1]*z12*y12;
c5e3e5d1 338
50ff0bcd 339}
340//--------------------------------------------------------------------------
fee9ef0d 341void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t *sigmasq,Double_t (*m)[3],Double_t *d)
342{
50ff0bcd 343 //
344 Double_t x12=p1[0]-p0[0];
345 Double_t y12=p1[1]-p0[1];
346 Double_t z12=p1[2]-p0[2];
c5e3e5d1 347
50ff0bcd 348 Double_t den= x12*x12*sigmasq[1]*sigmasq[2]+y12*y12*sigmasq[0]*sigmasq[2]+z12*z12*sigmasq[0]*sigmasq[1];
c5e3e5d1 349
50ff0bcd 350 Double_t kk= 2*(x12*x12/sigmasq[0]+y12*y12/sigmasq[1]+z12*z12/sigmasq[2]);
c5e3e5d1 351
50ff0bcd 352 Double_t cc[3];
353 cc[0]=-x12/sigmasq[0];
354 cc[1]=-y12/sigmasq[1];
355 cc[2]=-z12/sigmasq[2];
ec1be5d5 356
50ff0bcd 357 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 358
50ff0bcd 359 Double_t ss= -p0[0]*cc[0]-p0[1]*cc[1]-p0[2]*cc[2];
2d57349e 360
50ff0bcd 361 Double_t aa[3];
362 aa[0]=x12*sigmasq[1]*sigmasq[2]/den;
363 aa[1]=y12*sigmasq[0]*sigmasq[2]/den;
364 aa[2]=z12*sigmasq[0]*sigmasq[1]/den;
2d57349e 365
50ff0bcd 366 m[0][0]=aa[0]*(aa[0]*kk+2*cc[0])+2*cc[0]*aa[0]+2/sigmasq[0];
367 m[0][1]=aa[1]*(aa[0]*kk+2*cc[0])+2*cc[1]*aa[0];
368 m[0][2]=aa[2]*(aa[0]*kk+2*cc[0])+2*cc[2]*aa[0];
2d57349e 369
50ff0bcd 370 m[1][0]=aa[0]*(aa[1]*kk+2*cc[1])+2*cc[0]*aa[1];
371 m[1][1]=aa[1]*(aa[1]*kk+2*cc[1])+2*cc[1]*aa[1]+2/sigmasq[1];
372 m[1][2]=aa[2]*(aa[1]*kk+2*cc[1])+2*cc[2]*aa[1];
2d57349e 373
50ff0bcd 374 m[2][0]=aa[0]*(aa[2]*kk+2*cc[2])+2*cc[0]*aa[2];
375 m[2][1]=aa[1]*(aa[2]*kk+2*cc[2])+2*cc[1]*aa[2];
376 m[2][2]=aa[2]*(aa[2]*kk+2*cc[2])+2*cc[2]*aa[2]+2/sigmasq[2];
08df6187 377
50ff0bcd 378 d[0]=-ww*(aa[0]*kk+2*cc[0])-2*ss*aa[0]+2*p0[0]/sigmasq[0];
379 d[1]=-ww*(aa[1]*kk+2*cc[1])-2*ss*aa[1]+2*p0[1]/sigmasq[1];
380 d[2]=-ww*(aa[2]*kk+2*cc[2])-2*ss*aa[2]+2*p0[2]/sigmasq[2];
2d57349e 381
2d57349e 382 }
50ff0bcd 383//--------------------------------------------------------------------------
fee9ef0d 384Double_t AliVertexerTracks::GetStrLinMinDist(Double_t *p0,Double_t *p1,Double_t *x0)
385{
50ff0bcd 386 //
387 Double_t x12=p0[0]-p1[0];
388 Double_t y12=p0[1]-p1[1];
389 Double_t z12=p0[2]-p1[2];
390 Double_t x10=p0[0]-x0[0];
391 Double_t y10=p0[1]-x0[1];
392 Double_t z10=p0[2]-x0[2];
393 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 394}
395//---------------------------------------------------------------------------
fee9ef0d 396void AliVertexerTracks::OneTrackVertFinder()
397{
0c69be49 398 // find vertex for events with 1 track, using DCA to nominal beam axis
6d8df534 399 if(fDebug) printf("Number of prepared tracks =%d - Call OneTrackVertFinder",fTrkArraySel.GetEntries());
400 AliExternalTrackParam *track1;
401 track1 = (AliExternalTrackParam*)fTrkArraySel.At(0);
dc3719f3 402 Double_t field=GetFieldkG();
0c69be49 403 Double_t alpha=track1->GetAlpha();
404 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
405 Double_t pos[3],dir[3];
406 track1->GetXYZAt(mindist,field,pos);
407 track1->GetPxPyPzAt(mindist,field,dir);
408 AliStrLine *line1 = new AliStrLine(pos,dir);
409 Double_t p1[3]={fNominalPos[0],fNominalPos[1],0.};
410 Double_t p2[3]={fNominalPos[0],fNominalPos[1],10.};
411 AliStrLine *zeta=new AliStrLine(p1,p2,kTRUE);
412 Double_t crosspoint[3]={0.,0.,0.};
413 Double_t sigma=999.;
414 Int_t nContrib=-1;
415 Int_t retcode = zeta->Cross(line1,crosspoint);
416 if(retcode>=0){
417 sigma=line1->GetDistFromPoint(crosspoint);
418 nContrib=1;
419 }
420 delete zeta;
421 delete line1;
422 fVert.SetXYZ(crosspoint);
423 fVert.SetDispersion(sigma);
424 fVert.SetNContributors(nContrib);
425}
426//---------------------------------------------------------------------------
fee9ef0d 427void AliVertexerTracks::HelixVertexFinder()
428{
2d57349e 429 // Get estimate of vertex position in (x,y) from tracks DCA
430
431
432 Double_t initPos[3];
433 initPos[2] = 0.;
434 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
dc3719f3 435 Double_t field=GetFieldkG();
2d57349e 436
6d8df534 437 Int_t nacc = (Int_t)fTrkArraySel.GetEntriesFast();
2d57349e 438
439 Double_t aver[3]={0.,0.,0.};
440 Double_t averquad[3]={0.,0.,0.};
441 Double_t sigmaquad[3]={0.,0.,0.};
442 Double_t sigma=0;
443 Int_t ncombi = 0;
6d8df534 444 AliExternalTrackParam *track1;
445 AliExternalTrackParam *track2;
2d57349e 446 Double_t distCA;
6d8df534 447 Double_t x;
2d57349e 448 Double_t alpha, cs, sn;
449 Double_t crosspoint[3];
450 for(Int_t i=0; i<nacc; i++){
6d8df534 451 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
2d57349e 452
453
454 for(Int_t j=i+1; j<nacc; j++){
6d8df534 455 track2 = (AliExternalTrackParam*)fTrkArraySel.At(j);
2d57349e 456
457 distCA=track2->PropagateToDCA(track1,field);
2d57349e 458 if(fDCAcut<=0 ||(fDCAcut>0&&distCA<fDCAcut)){
6d8df534 459 x=track1->GetX();
2d57349e 460 alpha=track1->GetAlpha();
461 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
6d8df534 462 Double_t x1=x*cs - track1->GetY()*sn;
463 Double_t y1=x*sn + track1->GetY()*cs;
464 Double_t z1=track1->GetZ();
465
2d57349e 466 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
6d8df534 467 x=track2->GetX();
2d57349e 468 alpha=track2->GetAlpha();
469 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
6d8df534 470 Double_t x2=x*cs - track2->GetY()*sn;
471 Double_t y2=x*sn + track2->GetY()*cs;
472 Double_t z2=track2->GetZ();
2d57349e 473 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
474 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
475 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
476 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
477 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
478 crosspoint[0]=wx1*x1 + wx2*x2;
479 crosspoint[1]=wy1*y1 + wy2*y2;
480 crosspoint[2]=wz1*z1 + wz2*z2;
481
482 ncombi++;
483 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
484 for(Int_t jj=0;jj<3;jj++)averquad[jj]+=(crosspoint[jj]*crosspoint[jj]);
485 }
486 }
487
488 }
489 if(ncombi>0){
490 for(Int_t jj=0;jj<3;jj++){
491 initPos[jj] = aver[jj]/ncombi;
492 averquad[jj]/=ncombi;
493 sigmaquad[jj]=averquad[jj]-initPos[jj]*initPos[jj];
494 sigma+=sigmaquad[jj];
495 }
496 sigma=TMath::Sqrt(TMath::Abs(sigma));
497 }
498 else {
499 Warning("HelixVertexFinder","Finder did not succed");
500 sigma=999;
501 }
502 fVert.SetXYZ(initPos);
503 fVert.SetDispersion(sigma);
504 fVert.SetNContributors(ncombi);
505}
50ff0bcd 506//----------------------------------------------------------------------------
6d8df534 507Int_t AliVertexerTracks::PrepareTracks(TObjArray &trkArrayOrig,
508 UShort_t *idOrig,
509 Int_t optImpParCut)
fee9ef0d 510{
50ff0bcd 511//
512// Propagate tracks to initial vertex position and store them in a TObjArray
513//
6d8df534 514 if(fDebug) printf(" PrepareTracks()\n");
515
516 Int_t nTrksOrig = (Int_t)trkArrayOrig.GetEntriesFast();
517 Int_t nTrksSel = 0;
fee9ef0d 518 Double_t maxd0rphi;
519 Double_t maxd0z0 = fMaxd0z0; // default is 5 mm
50ff0bcd 520 Double_t sigmaCurr[3];
fee9ef0d 521 Double_t normdistx,normdisty;
6d8df534 522 Double_t d0z0[2],covd0z0[3];
50ff0bcd 523 Double_t sigma;
6d8df534 524 Double_t field = GetFieldkG();
50ff0bcd 525
526 AliESDVertex *initVertex = new AliESDVertex(fNominalPos,fNominalCov,1,1);
527
6d8df534 528 if(!fTrkArraySel.IsEmpty()) fTrkArraySel.Delete();
50ff0bcd 529
6d8df534 530 AliExternalTrackParam *track=0;
50ff0bcd 531
6d8df534 532 for(Int_t i=0; i<nTrksOrig; i++) {
533 track = new AliExternalTrackParam(*(AliExternalTrackParam*)trkArrayOrig.At(i));
534 // only TPC tracks in |eta|<0.9
535 if(!fITSrefit && TMath::Abs(track->GetTgl())>1.) {
536 delete track;
537 continue;
538 }
50ff0bcd 539
540 // propagate track to vertex
fee9ef0d 541 if(optImpParCut<=1 || fOnlyFitter) { // optImpParCut==1 or 0
6d8df534 542 track->PropagateToDCA(initVertex,field,100.,d0z0,covd0z0);
fee9ef0d 543 } else { // optImpParCut==2
50ff0bcd 544 fCurrentVertex->GetSigmaXYZ(sigmaCurr);
fee9ef0d 545 normdistx = TMath::Abs(fCurrentVertex->GetXv()-fNominalPos[0])/TMath::Sqrt(sigmaCurr[0]*sigmaCurr[0]+fNominalCov[0]);
80d36431 546 normdisty = TMath::Abs(fCurrentVertex->GetYv()-fNominalPos[1])/TMath::Sqrt(sigmaCurr[1]*sigmaCurr[1]+fNominalCov[2]);
fee9ef0d 547 if(normdistx < 3. && normdisty < 3. &&
80d36431 548 (sigmaCurr[0]+sigmaCurr[1])<(TMath::Sqrt(fNominalCov[0])+TMath::Sqrt(fNominalCov[2]))) {
6d8df534 549 track->PropagateToDCA(fCurrentVertex,field,100.,d0z0,covd0z0);
50ff0bcd 550 } else {
6d8df534 551 track->PropagateToDCA(initVertex,field,100.,d0z0,covd0z0);
50ff0bcd 552 }
553 }
554
50ff0bcd 555 sigma = TMath::Sqrt(covd0z0[0]);
556 maxd0rphi = fNSigma*sigma;
fee9ef0d 557 if(optImpParCut==1) maxd0rphi *= 5.;
558
6d8df534 559 if(fDebug) printf("trk %d; id %d; |d0| = %f; d0 cut = %f; |z0| = %f; |d0|oplus|z0| = %f; d0z0 cut = %f\n",i,(Int_t)idOrig[i],TMath::Abs(d0z0[0]),maxd0rphi,TMath::Abs(d0z0[1]),TMath::Sqrt(d0z0[0]*d0z0[0]+d0z0[1]*d0z0[1]),maxd0z0);
fee9ef0d 560
80d36431 561 // during iterations 1 and 2, if fConstraint=kFALSE,
fee9ef0d 562 // select tracks with d0oplusz0 < maxd0z0
6d8df534 563 if(optImpParCut>=1 && !fConstraint && nTrksOrig>=3 &&
fee9ef0d 564 fVert.GetNContributors()>0) {
565 if(TMath::Sqrt(d0z0[0]*d0z0[0]+d0z0[1]*d0z0[1]) > maxd0z0) {
566 if(fDebug) printf(" rejected\n");
567 delete track; continue;
568 }
569 }
570
571 // select tracks with d0rphi < maxd0rphi
6d8df534 572 if(optImpParCut>0 && TMath::Abs(d0z0[0])>maxd0rphi) {
50ff0bcd 573 if(fDebug) printf(" rejected\n");
574 delete track; continue;
575 }
576
6d8df534 577 fTrkArraySel.AddLast(track);
578 fIdSel[nTrksSel] = idOrig[i];
579 nTrksSel++;
50ff0bcd 580 }
581
582 delete initVertex;
583
6d8df534 584 return nTrksSel;
50ff0bcd 585}
586//---------------------------------------------------------------------------
fee9ef0d 587AliESDVertex* AliVertexerTracks::RemoveTracksFromVertex(AliESDVertex *inVtx,
6d8df534 588 TObjArray *trkArray,
589 UShort_t *id,
fee9ef0d 590 Float_t *diamondxy)
591{
50ff0bcd 592//
fee9ef0d 593// Removes tracks in trksTree from fit of inVtx
50ff0bcd 594//
fee9ef0d 595
146c29df 596 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraint")) {
597 printf("ERROR: primary vertex has no constraint: cannot remove tracks\n");
598 return 0x0;
599 }
fee9ef0d 600 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraintOnlyFitter"))
601 printf("WARNING: result of tracks' removal will be only approximately correct\n");
602
603 TMatrixD rv(3,1);
604 rv(0,0) = inVtx->GetXv();
605 rv(1,0) = inVtx->GetYv();
606 rv(2,0) = inVtx->GetZv();
607 TMatrixD vV(3,3);
608 Double_t cov[6];
609 inVtx->GetCovMatrix(cov);
610 vV(0,0) = cov[0];
611 vV(0,1) = cov[1]; vV(1,0) = cov[1];
612 vV(1,1) = cov[2];
613 vV(0,2) = cov[3]; vV(2,0) = cov[3];
614 vV(1,2) = cov[4]; vV(2,1) = cov[4];
615 vV(2,2) = cov[5];
616
617 TMatrixD sumWi(TMatrixD::kInverted,vV);
618 TMatrixD sumWiri(sumWi,TMatrixD::kMult,rv);
619
620 Int_t nUsedTrks = inVtx->GetNContributors();
621 Double_t chi2 = inVtx->GetChi2();
622
6d8df534 623 AliExternalTrackParam *track = 0;
624 Int_t ntrks = (Int_t)trkArray->GetEntriesFast();
fee9ef0d 625 for(Int_t i=0;i<ntrks;i++) {
6d8df534 626 track = (AliExternalTrackParam*)trkArray->At(i);
627 if(!inVtx->UsesTrack(id[i])) {
628 printf("track %d was not used in vertex fit\n",id[i]);
fee9ef0d 629 continue;
630 }
631 Double_t alpha = track->GetAlpha();
632 Double_t xl = diamondxy[0]*TMath::Cos(alpha)+diamondxy[1]*TMath::Sin(alpha);
6d8df534 633 track->PropagateTo(xl,GetFieldkG());
fee9ef0d 634 // vector of track global coordinates
635 TMatrixD ri(3,1);
636 // covariance matrix of ri
637 TMatrixD wWi(3,3);
638
639 // get space point from track
640 if(!TrackToPoint(track,ri,wWi)) continue;
641
642 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
643
644 sumWi -= wWi;
645 sumWiri -= wWiri;
646
647 // track chi2
648 TMatrixD deltar = rv; deltar -= ri;
649 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
650 Double_t chi2i = deltar(0,0)*wWideltar(0,0)+
651 deltar(1,0)*wWideltar(1,0)+
652 deltar(2,0)*wWideltar(2,0);
653 // remove from total chi2
654 chi2 -= chi2i;
655
656 nUsedTrks--;
657 if(nUsedTrks<2) {
658 printf("Trying to remove too many tracks!\n");
659 return 0x0;
660 }
661 }
662
663 TMatrixD rvnew(3,1);
664 TMatrixD vVnew(3,3);
665
666 // new inverted of weights matrix
667 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
668 vVnew = invsumWi;
669 // new position of primary vertex
670 rvnew.Mult(vVnew,sumWiri);
671
672 Double_t position[3];
673 position[0] = rvnew(0,0);
674 position[1] = rvnew(1,0);
675 position[2] = rvnew(2,0);
676 cov[0] = vVnew(0,0);
677 cov[1] = vVnew(0,1);
678 cov[2] = vVnew(1,1);
679 cov[3] = vVnew(0,2);
680 cov[4] = vVnew(1,2);
681 cov[5] = vVnew(2,2);
682
683 // store data in the vertex object
684 AliESDVertex *outVtx = new AliESDVertex(position,cov,chi2,nUsedTrks);
685 outVtx->SetTitle(inVtx->GetTitle());
fee9ef0d 686 UShort_t *inindices = inVtx->GetIndices();
687 UShort_t *outindices = new UShort_t[outVtx->GetNContributors()];
688 Int_t j=0;
fee9ef0d 689 for(Int_t k=0; k<inVtx->GetNIndices(); k++) {
6d8df534 690 Bool_t copyindex=kTRUE;
fee9ef0d 691 for(Int_t l=0; l<ntrks; l++) {
6d8df534 692 if(inindices[k]==id[l]) copyindex=kFALSE;
fee9ef0d 693 }
694 if(copyindex) {
695 outindices[j] = inindices[k]; j++;
696 }
697 }
698 outVtx->SetIndices(outVtx->GetNContributors(),outindices);
699 delete [] outindices;
700
701 if(fDebug) {
702 printf("Vertex before removing tracks:\n");
703 inVtx->PrintStatus();
704 inVtx->PrintIndices();
705 printf("Vertex after removing tracks:\n");
706 outVtx->PrintStatus();
707 outVtx->PrintIndices();
708 }
709
710 return outVtx;
711}
712//---------------------------------------------------------------------------
713void AliVertexerTracks::SetSkipTracks(Int_t n,Int_t *skipped)
714{
715//
716// Mark the tracks not to be used in the vertex reconstruction.
717// Tracks are identified by AliESDtrack::GetID()
718//
719 fNTrksToSkip = n; fTrksToSkip = new Int_t[n];
50ff0bcd 720 for(Int_t i=0;i<n;i++) fTrksToSkip[i] = skipped[i];
721 return;
722}
723//---------------------------------------------------------------------------
fee9ef0d 724void AliVertexerTracks::SetVtxStart(AliESDVertex *vtx)
725{
50ff0bcd 726//
727// Set initial vertex knowledge
728//
729 vtx->GetXYZ(fNominalPos);
730 vtx->GetCovMatrix(fNominalCov);
fee9ef0d 731 SetConstraintOn();
50ff0bcd 732 return;
733}
2d57349e 734//---------------------------------------------------------------------------
fee9ef0d 735void AliVertexerTracks::StrLinVertexFinderMinDist(Int_t optUseWeights)
dc3719f3 736{
6d8df534 737 AliExternalTrackParam *track1;
dc3719f3 738 Double_t field=GetFieldkG();
6d8df534 739 const Int_t knacc = (Int_t)fTrkArraySel.GetEntriesFast();
dc3719f3 740 TClonesArray *linarray = new TClonesArray("AliStrLine",1000);
741 TClonesArray &lines = *linarray;
742 for(Int_t i=0; i<knacc; i++){
6d8df534 743 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
dc3719f3 744 Double_t alpha=track1->GetAlpha();
745 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
746 Double_t pos[3],dir[3],sigmasq[3];
747 track1->GetXYZAt(mindist,field,pos);
748 track1->GetPxPyPzAt(mindist,field,dir);
749 sigmasq[0]=TMath::Sin(alpha)*TMath::Sin(alpha)*track1->GetSigmaY2();
750 sigmasq[1]=TMath::Cos(alpha)*TMath::Cos(alpha)*track1->GetSigmaY2();
751 sigmasq[2]=track1->GetSigmaZ2();
146c29df 752 TMatrixD ri(3,1);
753 TMatrixD wWi(3,3);
754 if(!TrackToPoint(track1,ri,wWi)) continue;
755 Double_t wmat[9];
756 Int_t iel=0;
757 for(Int_t ia=0;ia<3;ia++){
758 for(Int_t ib=0;ib<3;ib++){
759 wmat[iel]=wWi(ia,ib);
760 iel++;
761 }
762 }
763 new(lines[i]) AliStrLine(pos,sigmasq,wmat,dir);
dc3719f3 764 }
765 fVert=TrackletVertexFinder(linarray,optUseWeights);
766 linarray->Delete();
767 delete linarray;
768}
769//---------------------------------------------------------------------------
146c29df 770AliESDVertex AliVertexerTracks::TrackletVertexFinder(TClonesArray *lines, Int_t optUseWeights)
fee9ef0d 771{
2d57349e 772 // Calculate the point at minimum distance to prepared tracks
773
dc3719f3 774 const Int_t knacc = (Int_t)lines->GetEntriesFast();
775 Double_t initPos[3]={0.,0.,0.};
2d57349e 776
2d57349e 777 Double_t (*vectP0)[3]=new Double_t [knacc][3];
778 Double_t (*vectP1)[3]=new Double_t [knacc][3];
779
780 Double_t sum[3][3];
781 Double_t dsum[3]={0,0,0};
146c29df 782 TMatrixD sumWi(3,3);
783 for(Int_t i=0;i<3;i++){
784 for(Int_t j=0;j<3;j++){
785 sum[i][j]=0;
786 sumWi(i,j)=0.;
787 }
788 }
789
2d57349e 790 for(Int_t i=0; i<knacc; i++){
dc3719f3 791 AliStrLine* line1 = (AliStrLine*)lines->At(i);
792 Double_t p0[3],cd[3],sigmasq[3];
146c29df 793 Double_t wmat[9];
2d57349e 794 line1->GetP0(p0);
795 line1->GetCd(cd);
dc3719f3 796 line1->GetSigma2P0(sigmasq);
146c29df 797 line1->GetWMatrix(wmat);
798 TMatrixD wWi(3,3);
799 Int_t iel=0;
800 for(Int_t ia=0;ia<3;ia++){
801 for(Int_t ib=0;ib<3;ib++){
802 wWi(ia,ib)=wmat[iel];
803 iel++;
804 }
805 }
806
807 sumWi+=wWi;
808
2d57349e 809 Double_t p1[3]={p0[0]+cd[0],p0[1]+cd[1],p0[2]+cd[2]};
810 vectP0[i][0]=p0[0];
811 vectP0[i][1]=p0[1];
812 vectP0[i][2]=p0[2];
813 vectP1[i][0]=p1[0];
814 vectP1[i][1]=p1[1];
815 vectP1[i][2]=p1[2];
816
817 Double_t matr[3][3];
818 Double_t dknow[3];
819 if(optUseWeights==0)GetStrLinDerivMatrix(p0,p1,matr,dknow);
dc3719f3 820 else GetStrLinDerivMatrix(p0,p1,sigmasq,matr,dknow);
821
2d57349e 822
823 for(Int_t iii=0;iii<3;iii++){
824 dsum[iii]+=dknow[iii];
825 for(Int_t lj=0;lj<3;lj++) sum[iii][lj]+=matr[iii][lj];
826 }
2d57349e 827 }
146c29df 828
829 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
830 Double_t covmatrix[6];
831 covmatrix[0] = invsumWi(0,0);
832 covmatrix[1] = invsumWi(0,1);
833 covmatrix[2] = invsumWi(1,1);
834 covmatrix[3] = invsumWi(0,2);
835 covmatrix[4] = invsumWi(1,2);
836 covmatrix[5] = invsumWi(2,2);
837
2d57349e 838 Double_t vett[3][3];
839 Double_t det=GetDeterminant3X3(sum);
dc3719f3 840 Double_t sigma=0;
2d57349e 841
fee9ef0d 842 if(det!=0){
843 for(Int_t zz=0;zz<3;zz++){
844 for(Int_t ww=0;ww<3;ww++){
845 for(Int_t kk=0;kk<3;kk++) vett[ww][kk]=sum[ww][kk];
846 }
847 for(Int_t kk=0;kk<3;kk++) vett[kk][zz]=dsum[kk];
848 initPos[zz]=GetDeterminant3X3(vett)/det;
849 }
850
851
852 for(Int_t i=0; i<knacc; i++){
853 Double_t p0[3]={0,0,0},p1[3]={0,0,0};
854 for(Int_t ii=0;ii<3;ii++){
855 p0[ii]=vectP0[i][ii];
856 p1[ii]=vectP1[i][ii];
857 }
858 sigma+=GetStrLinMinDist(p0,p1,initPos);
859 }
860
861 sigma=TMath::Sqrt(sigma);
862 }else{
50ff0bcd 863 sigma=999;
864 }
146c29df 865 AliESDVertex theVert(initPos,covmatrix,99999.,knacc);
866 theVert.SetDispersion(sigma);
50ff0bcd 867 delete vectP0;
868 delete vectP1;
dc3719f3 869 return theVert;
50ff0bcd 870}
871//---------------------------------------------------------------------------
6d8df534 872Bool_t AliVertexerTracks::TrackToPoint(AliExternalTrackParam *t,
0bf2e2b4 873 TMatrixD &ri,TMatrixD &wWi,
874 Bool_t uUi3by3) const
fee9ef0d 875{
876//
6d8df534 877// Extract from the AliExternalTrackParam the global coordinates ri and covariance matrix
fee9ef0d 878// wWi of the space point that it represents (to be used in VertexFitter())
879//
880
881
882 Double_t rotAngle = t->GetAlpha();
883 if(rotAngle<0.) rotAngle += 2.*TMath::Pi();
884 Double_t cosRot = TMath::Cos(rotAngle);
885 Double_t sinRot = TMath::Sin(rotAngle);
886
887 ri(0,0) = t->GetX()*cosRot-t->GetY()*sinRot;
888 ri(1,0) = t->GetX()*sinRot+t->GetY()*cosRot;
889 ri(2,0) = t->GetZ();
890
0bf2e2b4 891
892
893 if(!uUi3by3) {
894 // matrix to go from global (x,y,z) to local (y,z);
895 TMatrixD qQi(2,3);
896 qQi(0,0) = -sinRot;
897 qQi(0,1) = cosRot;
898 qQi(0,2) = 0.;
899 qQi(1,0) = 0.;
900 qQi(1,1) = 0.;
901 qQi(1,2) = 1.;
902
903 // covariance matrix of local (y,z) - inverted
0bf2e2b4 904 TMatrixD uUi(2,2);
6d8df534 905 uUi(0,0) = t->GetSigmaY2();
906 uUi(0,1) = t->GetSigmaZY();
907 uUi(1,0) = t->GetSigmaZY();
908 uUi(1,1) = t->GetSigmaZ2();
0bf2e2b4 909 //printf(" Ui :\n");
910 //printf(" %f %f\n",uUi(0,0),uUi(0,1));
911 //printf(" %f %f\n",uUi(1,0),uUi(1,1));
912
913 if(uUi.Determinant() <= 0.) return kFALSE;
914 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
915
916 // weights matrix: wWi = qQiT * uUiInv * qQi
917 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
918 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
919 wWi = m;
920 } else {
921 if(fVert.GetNContributors()<1) AliFatal("Vertex from finder is empty");
922 // matrix to go from global (x,y,z) to local (x,y,z);
923 TMatrixD qQi(3,3);
924 qQi(0,0) = cosRot;
925 qQi(0,1) = sinRot;
926 qQi(0,2) = 0.;
927 qQi(1,0) = -sinRot;
928 qQi(1,1) = cosRot;
929 qQi(1,2) = 0.;
930 qQi(2,0) = 0.;
931 qQi(2,1) = 0.;
932 qQi(2,2) = 1.;
933
934 // covariance of fVert along the track
935 Double_t p[3],pt,ptot;
936 t->GetPxPyPz(p);
937 pt = TMath::Sqrt(p[0]*p[0]+p[1]*p[1]);
938 ptot = TMath::Sqrt(pt*pt+p[2]*p[2]);
3b768a1d 939 Double_t cphi = p[0]/pt; //cos(phi)=px/pt
940 Double_t sphi = p[1]/pt; //sin(phi)=py/pt
941 Double_t clambda = pt/ptot; //cos(lambda)=pt/ptot
942 Double_t slambda = p[2]/ptot; //sin(lambda)=pz/ptot
0bf2e2b4 943 Double_t covfVert[6];
944 fVert.GetCovMatrix(covfVert);
945 Double_t covfVertalongt =
3b768a1d 946 covfVert[0]*cphi*cphi*clambda*clambda
947 +covfVert[1]*2.*cphi*sphi*clambda*clambda
948 +covfVert[3]*2.*cphi*clambda*slambda
949 +covfVert[2]*sphi*sphi*clambda*clambda
950 +covfVert[4]*2.*sphi*clambda*slambda
951 +covfVert[5]*slambda*slambda;
0bf2e2b4 952 // covariance matrix of local (x,y,z) - inverted
953 TMatrixD uUi(3,3);
3b768a1d 954 uUi(0,0) = covfVertalongt * fnSigmaForUi00 * fnSigmaForUi00;
0bf2e2b4 955 if(fDebug) printf("=====> sqrtUi00 cm %f\n",TMath::Sqrt(uUi(0,0)));
956 uUi(0,1) = 0.;
957 uUi(0,2) = 0.;
958 uUi(1,0) = 0.;
6d8df534 959 uUi(1,1) = t->GetSigmaY2();
960 uUi(1,2) = t->GetSigmaZY();
0bf2e2b4 961 uUi(2,0) = 0.;
6d8df534 962 uUi(2,1) = t->GetSigmaZY();
963 uUi(2,2) = t->GetSigmaZ2();
0bf2e2b4 964 //printf(" Ui :\n");
965 //printf(" %f %f\n",uUi(0,0),uUi(0,1));
966 //printf(" %f %f\n",uUi(1,0),uUi(1,1));
fee9ef0d 967
0bf2e2b4 968 if(uUi.Determinant() <= 0.) return kFALSE;
969 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
970
971 // weights matrix: wWi = qQiT * uUiInv * qQi
972 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
973 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
974 wWi = m;
975 }
976
fee9ef0d 977
978 return kTRUE;
979}
980//---------------------------------------------------------------------------
6d8df534 981void AliVertexerTracks::TooFewTracks()
fee9ef0d 982{
50ff0bcd 983//
6d8df534 984// When the number of tracks is < fMinTracks,
985// deal with vertices not found and prepare to exit
50ff0bcd 986//
6d8df534 987 if(fDebug) printf("TooFewTracks\n");
2d57349e 988
50ff0bcd 989 Double_t pos[3],err[3];
50ff0bcd 990 pos[0] = fNominalPos[0];
991 err[0] = TMath::Sqrt(fNominalCov[0]);
992 pos[1] = fNominalPos[1];
993 err[1] = TMath::Sqrt(fNominalCov[2]);
6d8df534 994 pos[2] = fNominalPos[2];
995 err[2] = TMath::Sqrt(fNominalCov[5]);
996 Int_t ncontr = (err[0]>1. ? -1 : -3);
50ff0bcd 997 fCurrentVertex = 0;
998 fCurrentVertex = new AliESDVertex(pos,err);
999 fCurrentVertex->SetNContributors(ncontr);
2d57349e 1000
fee9ef0d 1001 if(fConstraint) {
1002 fCurrentVertex->SetTitle("VertexerTracksWithConstraint");
1003 } else {
50ff0bcd 1004 fCurrentVertex->SetTitle("VertexerTracksNoConstraint");
fee9ef0d 1005 }
2d57349e 1006
6d8df534 1007 if(!fTrkArraySel.IsEmpty()) fTrkArraySel.Delete();
1008 if(fIdSel) {delete [] fIdSel; fIdSel=NULL;}
1009 if(fTrksToSkip) {delete [] fTrksToSkip; fTrksToSkip=NULL;}
1010
50ff0bcd 1011 return;
1012}
1013//---------------------------------------------------------------------------
fee9ef0d 1014void AliVertexerTracks::VertexFinder(Int_t optUseWeights)
1015{
2d57349e 1016
50ff0bcd 1017 // Get estimate of vertex position in (x,y) from tracks DCA
1018
1019 Double_t initPos[3];
1020 initPos[2] = 0.;
1021 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
6d8df534 1022 Int_t nacc = (Int_t)fTrkArraySel.GetEntriesFast();
50ff0bcd 1023 Double_t aver[3]={0.,0.,0.};
1024 Double_t aversq[3]={0.,0.,0.};
1025 Double_t sigmasq[3]={0.,0.,0.};
1026 Double_t sigma=0;
1027 Int_t ncombi = 0;
6d8df534 1028 AliExternalTrackParam *track1;
1029 AliExternalTrackParam *track2;
50ff0bcd 1030 Double_t pos[3],dir[3];
1031 Double_t alpha,mindist;
dc3719f3 1032 Double_t field=GetFieldkG();
2d57349e 1033
50ff0bcd 1034 for(Int_t i=0; i<nacc; i++){
6d8df534 1035 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
50ff0bcd 1036 alpha=track1->GetAlpha();
1037 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1038 track1->GetXYZAt(mindist,field,pos);
1039 track1->GetPxPyPzAt(mindist,field,dir);
1040 AliStrLine *line1 = new AliStrLine(pos,dir);
2d57349e 1041
50ff0bcd 1042 // AliStrLine *line1 = new AliStrLine();
1043 // track1->ApproximateHelixWithLine(mindist,field,line1);
1044
1045 for(Int_t j=i+1; j<nacc; j++){
6d8df534 1046 track2 = (AliExternalTrackParam*)fTrkArraySel.At(j);
50ff0bcd 1047 alpha=track2->GetAlpha();
1048 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1049 track2->GetXYZAt(mindist,field,pos);
1050 track2->GetPxPyPzAt(mindist,field,dir);
1051 AliStrLine *line2 = new AliStrLine(pos,dir);
1052 // AliStrLine *line2 = new AliStrLine();
1053 // track2->ApproximateHelixWithLine(mindist,field,line2);
1054 Double_t distCA=line2->GetDCA(line1);
fee9ef0d 1055 //printf("%d %d %f\n",i,j,distCA);
1056 if(fDCAcut<=0 || (fDCAcut>0&&distCA<fDCAcut)){
50ff0bcd 1057 Double_t pnt1[3],pnt2[3],crosspoint[3];
2d57349e 1058
50ff0bcd 1059 if(optUseWeights<=0){
1060 Int_t retcode = line2->Cross(line1,crosspoint);
1061 if(retcode>=0){
1062 ncombi++;
1063 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
1064 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1065 }
1066 }
1067 if(optUseWeights>0){
1068 Int_t retcode = line1->CrossPoints(line2,pnt1,pnt2);
1069 if(retcode>=0){
5c03260f 1070 Double_t cs, sn;
50ff0bcd 1071 alpha=track1->GetAlpha();
1072 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
1073 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
1074 alpha=track2->GetAlpha();
1075 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
1076 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
1077 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
1078 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
1079 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
1080 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
1081 crosspoint[0]=wx1*pnt1[0] + wx2*pnt2[0];
1082 crosspoint[1]=wy1*pnt1[1] + wy2*pnt2[1];
1083 crosspoint[2]=wz1*pnt1[2] + wz2*pnt2[2];
1084
1085 ncombi++;
1086 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
1087 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1088 }
1089 }
1090 }
1091 delete line2;
1092 }
1093 delete line1;
71d84967 1094 }
50ff0bcd 1095 if(ncombi>0){
1096 for(Int_t jj=0;jj<3;jj++){
1097 initPos[jj] = aver[jj]/ncombi;
fee9ef0d 1098 //printf("%f\n",initPos[jj]);
50ff0bcd 1099 aversq[jj]/=ncombi;
1100 sigmasq[jj]=aversq[jj]-initPos[jj]*initPos[jj];
1101 sigma+=sigmasq[jj];
1102 }
1103 sigma=TMath::Sqrt(TMath::Abs(sigma));
1104 }
1105 else {
1106 Warning("VertexFinder","Finder did not succed");
1107 sigma=999;
1108 }
1109 fVert.SetXYZ(initPos);
1110 fVert.SetDispersion(sigma);
1111 fVert.SetNContributors(ncombi);
2d57349e 1112}
ec1be5d5 1113//---------------------------------------------------------------------------
6d8df534 1114void AliVertexerTracks::VertexFitter()
fee9ef0d 1115{
ec1be5d5 1116//
1117// The optimal estimate of the vertex position is given by a "weighted
0bf2e2b4 1118// average of tracks positions".
fee9ef0d 1119// Original method: V. Karimaki, CMS Note 97/0051
ec1be5d5 1120//
6d8df534 1121 Bool_t useConstraint = fConstraint;
ec1be5d5 1122 Double_t initPos[3];
0bf2e2b4 1123 if(!fOnlyFitter) {
1124 fVert.GetXYZ(initPos);
1125 } else {
1126 initPos[0]=fNominalPos[0];
1127 initPos[1]=fNominalPos[1];
1128 initPos[2]=fNominalPos[2];
1129 }
1130
6d8df534 1131 Int_t nTrksSel = (Int_t)fTrkArraySel.GetEntries();
1132 if(nTrksSel==1) useConstraint=kTRUE;
ec1be5d5 1133 if(fDebug) {
0bf2e2b4 1134 printf("--- VertexFitter(): start\n");
6d8df534 1135 printf(" Number of tracks in array: %d\n",nTrksSel);
ec1be5d5 1136 printf(" Minimum # tracks required in fit: %d\n",fMinTracks);
3b768a1d 1137 printf(" Vertex position after finder: %f,%f,%f\n",initPos[0],initPos[1],initPos[2]);
fee9ef0d 1138 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 1139 }
1140
0bf2e2b4 1141 // special treatment for few-tracks fits (e.g. secondary vertices)
6d8df534 1142 Bool_t uUi3by3 = kFALSE; if(nTrksSel<5 && !useConstraint) uUi3by3 = kTRUE;
0bf2e2b4 1143
ec1be5d5 1144 Int_t i,j,k,step=0;
1145 TMatrixD rv(3,1);
1146 TMatrixD vV(3,3);
1147 rv(0,0) = initPos[0];
1148 rv(1,0) = initPos[1];
1149 rv(2,0) = 0.;
1150 Double_t xlStart,alpha;
6d8df534 1151 Int_t nTrksUsed;
fee9ef0d 1152 Double_t chi2,chi2i,chi2b;
6d8df534 1153 AliExternalTrackParam *t = 0;
ec1be5d5 1154 Int_t failed = 0;
1155
50ff0bcd 1156 // initial vertex covariance matrix
1157 TMatrixD vVb(3,3);
1158 vVb(0,0) = fNominalCov[0];
1159 vVb(0,1) = fNominalCov[1];
1160 vVb(0,2) = 0.;
1161 vVb(1,0) = fNominalCov[1];
1162 vVb(1,1) = fNominalCov[2];
1163 vVb(1,2) = 0.;
1164 vVb(2,0) = 0.;
1165 vVb(2,1) = 0.;
1166 vVb(2,2) = fNominalCov[5];
1167 TMatrixD vVbInv(TMatrixD::kInverted,vVb);
1168 TMatrixD rb(3,1);
1169 rb(0,0) = fNominalPos[0];
1170 rb(1,0) = fNominalPos[1];
1171 rb(2,0) = fNominalPos[2];
1172 TMatrixD vVbInvrb(vVbInv,TMatrixD::kMult,rb);
1173
1174
eae1677e 1175 // 2 steps:
1176 // 1st - estimate of vtx using all tracks
1177 // 2nd - estimate of global chi2
1178 for(step=0; step<2; step++) {
ec1be5d5 1179 if(fDebug) printf(" step = %d\n",step);
1180 chi2 = 0.;
6d8df534 1181 nTrksUsed = 0;
ec1be5d5 1182
0bf2e2b4 1183 if(step==1) { initPos[0]=rv(0,0); initPos[0]=rv(1,0); }
1184
ec1be5d5 1185 TMatrixD sumWiri(3,1);
1186 TMatrixD sumWi(3,3);
1187 for(i=0; i<3; i++) {
1188 sumWiri(i,0) = 0.;
1189 for(j=0; j<3; j++) sumWi(j,i) = 0.;
1190 }
1191
fee9ef0d 1192 // mean vertex constraint
1193 if(useConstraint) {
50ff0bcd 1194 for(i=0;i<3;i++) {
1195 sumWiri(i,0) += vVbInvrb(i,0);
1196 for(k=0;k<3;k++) sumWi(i,k) += vVbInv(i,k);
07680cae 1197 }
fee9ef0d 1198 // chi2
1199 TMatrixD deltar = rv; deltar -= rb;
1200 TMatrixD vVbInvdeltar(vVbInv,TMatrixD::kMult,deltar);
1201 chi2b = deltar(0,0)*vVbInvdeltar(0,0)+
1202 deltar(1,0)*vVbInvdeltar(1,0)+
1203 deltar(2,0)*vVbInvdeltar(2,0);
1204 chi2 += chi2b;
07680cae 1205 }
1206
ec1be5d5 1207 // loop on tracks
6d8df534 1208 for(k=0; k<nTrksSel; k++) {
ec1be5d5 1209 // get track from track array
6d8df534 1210 t = (AliExternalTrackParam*)fTrkArraySel.At(k);
ec1be5d5 1211 alpha = t->GetAlpha();
1212 xlStart = initPos[0]*TMath::Cos(alpha)+initPos[1]*TMath::Sin(alpha);
fee9ef0d 1213 // to vtxSeed (from finder)
6d8df534 1214 t->PropagateTo(xlStart,GetFieldkG());
fee9ef0d 1215
ec1be5d5 1216 // vector of track global coordinates
1217 TMatrixD ri(3,1);
fee9ef0d 1218 // covariance matrix of ri
1219 TMatrixD wWi(3,3);
1220
1221 // get space point from track
0bf2e2b4 1222 if(!TrackToPoint(t,ri,wWi,uUi3by3)) continue;
fee9ef0d 1223 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
ec1be5d5 1224
1225 // track chi2
1226 TMatrixD deltar = rv; deltar -= ri;
1227 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
1228 chi2i = deltar(0,0)*wWideltar(0,0)+
1229 deltar(1,0)*wWideltar(1,0)+
1230 deltar(2,0)*wWideltar(2,0);
1231
ec1be5d5 1232 // add to total chi2
1233 chi2 += chi2i;
1234
ec1be5d5 1235 sumWiri += wWiri;
1236 sumWi += wWi;
1237
6d8df534 1238 nTrksUsed++;
ec1be5d5 1239 } // end loop on tracks
1240
6d8df534 1241 if(nTrksUsed < fMinTracks) {
ec1be5d5 1242 failed=1;
1243 continue;
1244 }
1245
1246 Double_t determinant = sumWi.Determinant();
1247 //cerr<<" determinant: "<<determinant<<endl;
1248 if(determinant < 100.) {
1249 printf("det(V) = 0\n");
1250 failed=1;
1251 continue;
1252 }
1253
0bf2e2b4 1254 if(step==0) {
1255 // inverted of weights matrix
1256 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
1257 vV = invsumWi;
1258 // position of primary vertex
1259 rv.Mult(vV,sumWiri);
1260 }
eae1677e 1261 } // end loop on the 2 steps
ec1be5d5 1262
ec1be5d5 1263 if(failed) {
6d8df534 1264 TooFewTracks();
ec1be5d5 1265 return;
1266 }
1267
1268 Double_t position[3];
1269 position[0] = rv(0,0);
1270 position[1] = rv(1,0);
1271 position[2] = rv(2,0);
1272 Double_t covmatrix[6];
1273 covmatrix[0] = vV(0,0);
1274 covmatrix[1] = vV(0,1);
1275 covmatrix[2] = vV(1,1);
1276 covmatrix[3] = vV(0,2);
1277 covmatrix[4] = vV(1,2);
1278 covmatrix[5] = vV(2,2);
1279
dc3719f3 1280 // for correct chi2/ndf, count constraint as additional "track"
6d8df534 1281 if(fConstraint) nTrksUsed++;
ec1be5d5 1282 // store data in the vertex object
6d8df534 1283 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nTrksUsed);
ec1be5d5 1284
1285 if(fDebug) {
0bf2e2b4 1286 printf(" Vertex after fit:\n");
ec1be5d5 1287 fCurrentVertex->PrintStatus();
0bf2e2b4 1288 printf("--- VertexFitter(): finish\n");
ec1be5d5 1289 }
1290
1291 return;
1292}
50ff0bcd 1293//----------------------------------------------------------------------------
6d8df534 1294AliESDVertex* AliVertexerTracks::VertexForSelectedTracks(TObjArray *trkArray,
1295 UShort_t *id,
1296 Bool_t optUseFitter,
1297 Bool_t optPropagate)
fee9ef0d 1298{
eae1677e 1299//
6d8df534 1300// Return vertex from tracks (AliExternalTrackParam) in array
eae1677e 1301//
1302
fee9ef0d 1303 SetConstraintOff();
1304
50ff0bcd 1305 // get tracks and propagate them to initial vertex position
6d8df534 1306 fIdSel = new UShort_t[(Int_t)trkArray->GetEntriesFast()];
1307 Int_t nTrksSel = PrepareTracks(*trkArray,id,0);
1308 if(nTrksSel < TMath::Max(2,fMinTracks)) {
1309 TooFewTracks();
fee9ef0d 1310 return fCurrentVertex;
50ff0bcd 1311 }
1312
6d8df534 1313 // vertex finder
fee9ef0d 1314 switch (fAlgo) {
1315 case 1: StrLinVertexFinderMinDist(1); break;
1316 case 2: StrLinVertexFinderMinDist(0); break;
1317 case 3: HelixVertexFinder(); break;
1318 case 4: VertexFinder(1); break;
1319 case 5: VertexFinder(0); break;
1320 default: printf("Wrong algorithm\n"); break;
1321 }
fee9ef0d 1322 if(fDebug) printf(" Vertex finding completed\n");
1323
1324 // vertex fitter
6d8df534 1325 if(optUseFitter) {
1326 VertexFitter();
1327 } else {
fee9ef0d 1328 Double_t position[3]={fVert.GetXv(),fVert.GetYv(),fVert.GetZv()};
146c29df 1329 Double_t covmatrix[6];
1330 fVert.GetCovMatrix(covmatrix);
fee9ef0d 1331 Double_t chi2=99999.;
6d8df534 1332 Int_t nTrksUsed=fVert.GetNContributors();
1333 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nTrksUsed);
fee9ef0d 1334 }
1335 fCurrentVertex->SetDispersion(fVert.GetDispersion());
1336
1337
1338 // set indices of used tracks and propagate track to found vertex
50ff0bcd 1339 UShort_t *indices = 0;
6d8df534 1340 Double_t d0z0[2],covd0z0[3];
1341 AliExternalTrackParam *t = 0;
fee9ef0d 1342 if(fCurrentVertex->GetNContributors()>0) {
1343 indices = new UShort_t[fCurrentVertex->GetNContributors()];
6d8df534 1344 for(Int_t jj=0; jj<(Int_t)fTrkArraySel.GetEntriesFast(); jj++) {
1345 indices[jj] = fIdSel[jj];
1346 t = (AliExternalTrackParam*)fTrkArraySel.At(jj);
1347 if(optPropagate && optUseFitter) {
fee9ef0d 1348 if(TMath::Sqrt(fCurrentVertex->GetXv()*fCurrentVertex->GetXv()+fCurrentVertex->GetYv()*fCurrentVertex->GetYv())<3.) {
6d8df534 1349 t->PropagateToDCA(fCurrentVertex,GetFieldkG(),100.,d0z0,covd0z0);
fee9ef0d 1350 if(fDebug) printf("Track %d propagated to found vertex\n",jj);
6d8df534 1351 } else {
fee9ef0d 1352 AliWarning("Found vertex outside beam pipe!");
1353 }
1354 }
50ff0bcd 1355 }
fee9ef0d 1356 fCurrentVertex->SetIndices(fCurrentVertex->GetNContributors(),indices);
50ff0bcd 1357 }
6d8df534 1358
1359 // clean up
1360 delete [] indices; indices=NULL;
1361 delete [] fIdSel; fIdSel=NULL;
1362 fTrkArraySel.Delete();
50ff0bcd 1363
fee9ef0d 1364 return fCurrentVertex;
eae1677e 1365}
50ff0bcd 1366//----------------------------------------------------------------------------
6d8df534 1367AliESDVertex* AliVertexerTracks::VertexForSelectedESDTracks(TObjArray *trkArray,
1368 Bool_t optUseFitter,
1369 Bool_t optPropagate)
fee9ef0d 1370{
50ff0bcd 1371//
6d8df534 1372// Return vertex from array of ESD tracks
50ff0bcd 1373//
5834e9a1 1374
6d8df534 1375 Int_t nTrks = (Int_t)trkArray->GetEntriesFast();
1376 UShort_t *id = new UShort_t[nTrks];
1377
1378 AliESDtrack *esdt = 0;
50ff0bcd 1379 for(Int_t i=0; i<nTrks; i++){
6d8df534 1380 esdt = (AliESDtrack*)trkArray->At(i);
1381 id[i] = (UShort_t)esdt->GetID();
50ff0bcd 1382 }
1383
6d8df534 1384 VertexForSelectedTracks(trkArray,id,optUseFitter,optPropagate);
1385
1386 delete [] id; id=NULL;
1387
1388 return fCurrentVertex;
50ff0bcd 1389}
1390//--------------------------------------------------------------------------