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Correcting a minor bug (A. Dainese)
[u/mrichter/AliRoot.git] / STEER / AliVertexerTracks.cxx
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2d57349e 1/**************************************************************************
2 * Copyright(c) 1998-2003, ALICE Experiment at CERN, All rights reserved. *
3 * *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
6 * *
7 * Permission to use, copy, modify and distribute this software and its *
8 * documentation strictly for non-commercial purposes is hereby granted *
9 * without fee, provided that the above copyright notice appears in all *
10 * copies and that both the copyright notice and this permission notice *
11 * appear in the supporting documentation. The authors make no claims *
12 * about the suitability of this software for any purpose. It is *
13 * provided "as is" without express or implied warranty. *
14 **************************************************************************/
15
16//-----------------------------------------------------------------
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();
43c9dae1 202 if(fDebug) printf("Initial number of tracks: %d\n",nTrksOrig);
6d8df534 203 if(nTrksOrig<=0) {
204 if(fDebug) printf("TooFewTracks\n");
205 TooFewTracks();
206 return fCurrentVertex;
207 }
208
fee9ef0d 209 // If fConstraint=kFALSE
210 // run VertexFinder(1) to get rough estimate of initVertex (x,y)
211 if(!fConstraint) {
6d8df534 212 // fill fTrkArraySel, for VertexFinder()
213 fIdSel = new UShort_t[nTrksOrig];
214 PrepareTracks(*trkArrayOrig,idOrig,0);
215 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
216 Double_t cutsave = fDCAcut;
217 fDCAcut = (fITSrefit ? 0.1 : 0.5);
fee9ef0d 218 VertexFinder(1); // using weights, cutting dca < fDCAcut
219 fDCAcut = cutsave;
fee9ef0d 220 if(fVert.GetNContributors()>0) {
221 fVert.GetXYZ(fNominalPos);
222 fNominalPos[0] = fVert.GetXv();
223 fNominalPos[1] = fVert.GetYv();
224 fNominalPos[2] = fVert.GetZv();
225 if(fDebug) printf("No mean vertex: VertexFinder gives (%f, %f, %f)\n",fNominalPos[0],fNominalPos[1],fNominalPos[2]);
226 } else {
227 fNominalPos[0] = 0.;
228 fNominalPos[1] = 0.;
229 fNominalPos[2] = 0.;
230 if(fDebug) printf("No mean vertex and VertexFinder failed\n");
0c69be49 231 }
07680cae 232 }
fee9ef0d 233
234 // TWO ITERATIONS:
235 //
236 // ITERATION 1
237 // propagate tracks to fNominalPos vertex
238 // preselect them:
239 // if(constraint) reject for |d0|>5*fNSigma*sigma w.r.t. fNominal... vertex
240 // else reject for |d0|\oplus|z0| > 5 mm w.r.t. fNominal... vertex
07680cae 241 // ITERATION 2
242 // propagate tracks to best between initVertex and fCurrentVertex
243 // preselect tracks (reject for |d0|>fNSigma*sigma w.r.t. best
244 // between initVertex and fCurrentVertex)
6d8df534 245 for(Int_t iter=1; iter<=2; iter++) {
246 if(fOnlyFitter && iter==1) continue;
247 if(fIdSel) { delete [] fIdSel; fIdSel=NULL; }
248 fIdSel = new UShort_t[nTrksOrig];
249 Int_t nTrksSel = PrepareTracks(*trkArrayOrig,idOrig,iter);
250 if(fDebug) printf("N tracks selected in iteration %d: %d\n",iter,nTrksSel);
251 if(nTrksSel < fMinTracks) {
252 TooFewTracks();
fee9ef0d 253 return fCurrentVertex;
254 }
07680cae 255
fee9ef0d 256 // vertex finder
257 if(!fOnlyFitter) {
6d8df534 258 if(nTrksSel==1) {
fee9ef0d 259 if(fDebug) printf("Just one track\n");
260 OneTrackVertFinder();
6d8df534 261 } else {
fee9ef0d 262 switch (fAlgo) {
263 case 1: StrLinVertexFinderMinDist(1); break;
264 case 2: StrLinVertexFinderMinDist(0); break;
265 case 3: HelixVertexFinder(); break;
266 case 4: VertexFinder(1); break;
267 case 5: VertexFinder(0); break;
268 default: printf("Wrong algorithm\n"); break;
269 }
270 }
271 if(fDebug) printf(" Vertex finding completed\n");
0c69be49 272 }
07680cae 273
fee9ef0d 274 // vertex fitter
6d8df534 275 VertexFitter();
fee9ef0d 276 } // end loop on the two iterations
07680cae 277
fee9ef0d 278
50ff0bcd 279 // set indices of used tracks
280 UShort_t *indices = 0;
50ff0bcd 281 if(fCurrentVertex->GetNContributors()>0) {
4d023a8f 282 Int_t nIndices = (Int_t)fTrkArraySel.GetEntriesFast();
283 indices = new UShort_t[nIndices];
284 for(Int_t jj=0; jj<nIndices; jj++)
6d8df534 285 indices[jj] = fIdSel[jj];
4d023a8f 286 fCurrentVertex->SetIndices(nIndices,indices);
50ff0bcd 287 }
6d8df534 288 delete [] indices; indices=NULL;
289 //
fee9ef0d 290
6d8df534 291 // set vertex title
292 TString title="VertexerTracksNoConstraint";
293 if(fConstraint) {
294 title="VertexerTracksWithConstraint";
295 if(fOnlyFitter) title.Append("OnlyFitter");
296 }
297 fCurrentVertex->SetTitle(title.Data());
298 //
a7ede274 299
6d8df534 300 if(fDebug) {
301 fCurrentVertex->PrintStatus();
302 fCurrentVertex->PrintIndices();
303 }
50ff0bcd 304
6d8df534 305 // clean up
306 delete [] fIdSel; fIdSel=NULL;
307 fTrkArraySel.Delete();
146c29df 308 if(fTrksToSkip) { delete [] fTrksToSkip; fTrksToSkip=NULL; }
6d8df534 309 //
fee9ef0d 310
07680cae 311 return fCurrentVertex;
312}
50ff0bcd 313//------------------------------------------------------------------------
fee9ef0d 314Double_t AliVertexerTracks::GetDeterminant3X3(Double_t matr[][3])
315{
50ff0bcd 316 //
317 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];
318 return det;
319}
320//-------------------------------------------------------------------------
fee9ef0d 321void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t (*m)[3],Double_t *d)
322{
50ff0bcd 323 //
324 Double_t x12=p0[0]-p1[0];
325 Double_t y12=p0[1]-p1[1];
326 Double_t z12=p0[2]-p1[2];
327 Double_t kk=x12*x12+y12*y12+z12*z12;
328 m[0][0]=2-2/kk*x12*x12;
329 m[0][1]=-2/kk*x12*y12;
330 m[0][2]=-2/kk*x12*z12;
331 m[1][0]=-2/kk*x12*y12;
332 m[1][1]=2-2/kk*y12*y12;
333 m[1][2]=-2/kk*y12*z12;
334 m[2][0]=-2/kk*x12*z12;
335 m[2][1]=-2*y12*z12;
336 m[2][2]=2-2/kk*z12*z12;
337 d[0]=2*p0[0]-2/kk*p0[0]*x12*x12-2/kk*p0[2]*x12*z12-2/kk*p0[1]*x12*y12;
338 d[1]=2*p0[1]-2/kk*p0[1]*y12*y12-2/kk*p0[0]*x12*y12-2/kk*p0[2]*z12*y12;
339 d[2]=2*p0[2]-2/kk*p0[2]*z12*z12-2/kk*p0[0]*x12*z12-2/kk*p0[1]*z12*y12;
c5e3e5d1 340
50ff0bcd 341}
342//--------------------------------------------------------------------------
fee9ef0d 343void AliVertexerTracks::GetStrLinDerivMatrix(Double_t *p0,Double_t *p1,Double_t *sigmasq,Double_t (*m)[3],Double_t *d)
344{
50ff0bcd 345 //
346 Double_t x12=p1[0]-p0[0];
347 Double_t y12=p1[1]-p0[1];
348 Double_t z12=p1[2]-p0[2];
c5e3e5d1 349
50ff0bcd 350 Double_t den= x12*x12*sigmasq[1]*sigmasq[2]+y12*y12*sigmasq[0]*sigmasq[2]+z12*z12*sigmasq[0]*sigmasq[1];
c5e3e5d1 351
50ff0bcd 352 Double_t kk= 2*(x12*x12/sigmasq[0]+y12*y12/sigmasq[1]+z12*z12/sigmasq[2]);
c5e3e5d1 353
50ff0bcd 354 Double_t cc[3];
355 cc[0]=-x12/sigmasq[0];
356 cc[1]=-y12/sigmasq[1];
357 cc[2]=-z12/sigmasq[2];
ec1be5d5 358
50ff0bcd 359 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 360
50ff0bcd 361 Double_t ss= -p0[0]*cc[0]-p0[1]*cc[1]-p0[2]*cc[2];
2d57349e 362
50ff0bcd 363 Double_t aa[3];
364 aa[0]=x12*sigmasq[1]*sigmasq[2]/den;
365 aa[1]=y12*sigmasq[0]*sigmasq[2]/den;
366 aa[2]=z12*sigmasq[0]*sigmasq[1]/den;
2d57349e 367
50ff0bcd 368 m[0][0]=aa[0]*(aa[0]*kk+2*cc[0])+2*cc[0]*aa[0]+2/sigmasq[0];
369 m[0][1]=aa[1]*(aa[0]*kk+2*cc[0])+2*cc[1]*aa[0];
370 m[0][2]=aa[2]*(aa[0]*kk+2*cc[0])+2*cc[2]*aa[0];
2d57349e 371
50ff0bcd 372 m[1][0]=aa[0]*(aa[1]*kk+2*cc[1])+2*cc[0]*aa[1];
373 m[1][1]=aa[1]*(aa[1]*kk+2*cc[1])+2*cc[1]*aa[1]+2/sigmasq[1];
374 m[1][2]=aa[2]*(aa[1]*kk+2*cc[1])+2*cc[2]*aa[1];
2d57349e 375
50ff0bcd 376 m[2][0]=aa[0]*(aa[2]*kk+2*cc[2])+2*cc[0]*aa[2];
377 m[2][1]=aa[1]*(aa[2]*kk+2*cc[2])+2*cc[1]*aa[2];
378 m[2][2]=aa[2]*(aa[2]*kk+2*cc[2])+2*cc[2]*aa[2]+2/sigmasq[2];
08df6187 379
50ff0bcd 380 d[0]=-ww*(aa[0]*kk+2*cc[0])-2*ss*aa[0]+2*p0[0]/sigmasq[0];
381 d[1]=-ww*(aa[1]*kk+2*cc[1])-2*ss*aa[1]+2*p0[1]/sigmasq[1];
382 d[2]=-ww*(aa[2]*kk+2*cc[2])-2*ss*aa[2]+2*p0[2]/sigmasq[2];
2d57349e 383
2d57349e 384 }
50ff0bcd 385//--------------------------------------------------------------------------
fee9ef0d 386Double_t AliVertexerTracks::GetStrLinMinDist(Double_t *p0,Double_t *p1,Double_t *x0)
387{
50ff0bcd 388 //
389 Double_t x12=p0[0]-p1[0];
390 Double_t y12=p0[1]-p1[1];
391 Double_t z12=p0[2]-p1[2];
392 Double_t x10=p0[0]-x0[0];
393 Double_t y10=p0[1]-x0[1];
394 Double_t z10=p0[2]-x0[2];
395 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 396}
397//---------------------------------------------------------------------------
fee9ef0d 398void AliVertexerTracks::OneTrackVertFinder()
399{
0c69be49 400 // find vertex for events with 1 track, using DCA to nominal beam axis
6d8df534 401 if(fDebug) printf("Number of prepared tracks =%d - Call OneTrackVertFinder",fTrkArraySel.GetEntries());
402 AliExternalTrackParam *track1;
403 track1 = (AliExternalTrackParam*)fTrkArraySel.At(0);
dc3719f3 404 Double_t field=GetFieldkG();
0c69be49 405 Double_t alpha=track1->GetAlpha();
406 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
407 Double_t pos[3],dir[3];
408 track1->GetXYZAt(mindist,field,pos);
409 track1->GetPxPyPzAt(mindist,field,dir);
410 AliStrLine *line1 = new AliStrLine(pos,dir);
411 Double_t p1[3]={fNominalPos[0],fNominalPos[1],0.};
412 Double_t p2[3]={fNominalPos[0],fNominalPos[1],10.};
413 AliStrLine *zeta=new AliStrLine(p1,p2,kTRUE);
414 Double_t crosspoint[3]={0.,0.,0.};
415 Double_t sigma=999.;
416 Int_t nContrib=-1;
417 Int_t retcode = zeta->Cross(line1,crosspoint);
418 if(retcode>=0){
419 sigma=line1->GetDistFromPoint(crosspoint);
420 nContrib=1;
421 }
422 delete zeta;
423 delete line1;
424 fVert.SetXYZ(crosspoint);
425 fVert.SetDispersion(sigma);
426 fVert.SetNContributors(nContrib);
427}
428//---------------------------------------------------------------------------
fee9ef0d 429void AliVertexerTracks::HelixVertexFinder()
430{
2d57349e 431 // Get estimate of vertex position in (x,y) from tracks DCA
432
433
434 Double_t initPos[3];
435 initPos[2] = 0.;
436 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
dc3719f3 437 Double_t field=GetFieldkG();
2d57349e 438
6d8df534 439 Int_t nacc = (Int_t)fTrkArraySel.GetEntriesFast();
2d57349e 440
441 Double_t aver[3]={0.,0.,0.};
442 Double_t averquad[3]={0.,0.,0.};
443 Double_t sigmaquad[3]={0.,0.,0.};
444 Double_t sigma=0;
445 Int_t ncombi = 0;
6d8df534 446 AliExternalTrackParam *track1;
447 AliExternalTrackParam *track2;
2d57349e 448 Double_t distCA;
6d8df534 449 Double_t x;
2d57349e 450 Double_t alpha, cs, sn;
451 Double_t crosspoint[3];
452 for(Int_t i=0; i<nacc; i++){
6d8df534 453 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
2d57349e 454
455
456 for(Int_t j=i+1; j<nacc; j++){
6d8df534 457 track2 = (AliExternalTrackParam*)fTrkArraySel.At(j);
2d57349e 458
459 distCA=track2->PropagateToDCA(track1,field);
2d57349e 460 if(fDCAcut<=0 ||(fDCAcut>0&&distCA<fDCAcut)){
6d8df534 461 x=track1->GetX();
2d57349e 462 alpha=track1->GetAlpha();
463 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
6d8df534 464 Double_t x1=x*cs - track1->GetY()*sn;
465 Double_t y1=x*sn + track1->GetY()*cs;
466 Double_t z1=track1->GetZ();
467
2d57349e 468 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
6d8df534 469 x=track2->GetX();
2d57349e 470 alpha=track2->GetAlpha();
471 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
6d8df534 472 Double_t x2=x*cs - track2->GetY()*sn;
473 Double_t y2=x*sn + track2->GetY()*cs;
474 Double_t z2=track2->GetZ();
2d57349e 475 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
476 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
477 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
478 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
479 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
480 crosspoint[0]=wx1*x1 + wx2*x2;
481 crosspoint[1]=wy1*y1 + wy2*y2;
482 crosspoint[2]=wz1*z1 + wz2*z2;
483
484 ncombi++;
485 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
486 for(Int_t jj=0;jj<3;jj++)averquad[jj]+=(crosspoint[jj]*crosspoint[jj]);
487 }
488 }
489
490 }
491 if(ncombi>0){
492 for(Int_t jj=0;jj<3;jj++){
493 initPos[jj] = aver[jj]/ncombi;
494 averquad[jj]/=ncombi;
495 sigmaquad[jj]=averquad[jj]-initPos[jj]*initPos[jj];
496 sigma+=sigmaquad[jj];
497 }
498 sigma=TMath::Sqrt(TMath::Abs(sigma));
499 }
500 else {
501 Warning("HelixVertexFinder","Finder did not succed");
502 sigma=999;
503 }
504 fVert.SetXYZ(initPos);
505 fVert.SetDispersion(sigma);
506 fVert.SetNContributors(ncombi);
507}
50ff0bcd 508//----------------------------------------------------------------------------
6d8df534 509Int_t AliVertexerTracks::PrepareTracks(TObjArray &trkArrayOrig,
510 UShort_t *idOrig,
511 Int_t optImpParCut)
fee9ef0d 512{
50ff0bcd 513//
514// Propagate tracks to initial vertex position and store them in a TObjArray
515//
6d8df534 516 if(fDebug) printf(" PrepareTracks()\n");
517
518 Int_t nTrksOrig = (Int_t)trkArrayOrig.GetEntriesFast();
519 Int_t nTrksSel = 0;
fee9ef0d 520 Double_t maxd0rphi;
43c9dae1 521 Double_t maxd0z0 = (fITSrefit ? fMaxd0z0 : 10.*fMaxd0z0);
50ff0bcd 522 Double_t sigmaCurr[3];
fee9ef0d 523 Double_t normdistx,normdisty;
6d8df534 524 Double_t d0z0[2],covd0z0[3];
43c9dae1 525 Double_t sigmad0;
6d8df534 526 Double_t field = GetFieldkG();
50ff0bcd 527
528 AliESDVertex *initVertex = new AliESDVertex(fNominalPos,fNominalCov,1,1);
529
6d8df534 530 if(!fTrkArraySel.IsEmpty()) fTrkArraySel.Delete();
50ff0bcd 531
6d8df534 532 AliExternalTrackParam *track=0;
50ff0bcd 533
6d8df534 534 for(Int_t i=0; i<nTrksOrig; i++) {
535 track = new AliExternalTrackParam(*(AliExternalTrackParam*)trkArrayOrig.At(i));
536 // only TPC tracks in |eta|<0.9
537 if(!fITSrefit && TMath::Abs(track->GetTgl())>1.) {
43c9dae1 538 if(fDebug) printf(" rejecting track with tgl = %f\n",track->GetTgl());
6d8df534 539 delete track;
540 continue;
541 }
50ff0bcd 542
543 // propagate track to vertex
43c9dae1 544 if(optImpParCut<2 || fOnlyFitter) { // optImpParCut==1 or 0
6d8df534 545 track->PropagateToDCA(initVertex,field,100.,d0z0,covd0z0);
fee9ef0d 546 } else { // optImpParCut==2
50ff0bcd 547 fCurrentVertex->GetSigmaXYZ(sigmaCurr);
fee9ef0d 548 normdistx = TMath::Abs(fCurrentVertex->GetXv()-fNominalPos[0])/TMath::Sqrt(sigmaCurr[0]*sigmaCurr[0]+fNominalCov[0]);
80d36431 549 normdisty = TMath::Abs(fCurrentVertex->GetYv()-fNominalPos[1])/TMath::Sqrt(sigmaCurr[1]*sigmaCurr[1]+fNominalCov[2]);
fee9ef0d 550 if(normdistx < 3. && normdisty < 3. &&
80d36431 551 (sigmaCurr[0]+sigmaCurr[1])<(TMath::Sqrt(fNominalCov[0])+TMath::Sqrt(fNominalCov[2]))) {
6d8df534 552 track->PropagateToDCA(fCurrentVertex,field,100.,d0z0,covd0z0);
50ff0bcd 553 } else {
6d8df534 554 track->PropagateToDCA(initVertex,field,100.,d0z0,covd0z0);
50ff0bcd 555 }
556 }
557
43c9dae1 558 sigmad0 = TMath::Sqrt(covd0z0[0]);
559 maxd0rphi = fNSigma*sigmad0;
fee9ef0d 560 if(optImpParCut==1) maxd0rphi *= 5.;
43c9dae1 561 //sigmad0z0 = TMath::Sqrt(covd0z0[0]+covd0z0[2]); // for future improvement
562 //maxd0z0 = 10.*fNSigma*sigmad0z0;
fee9ef0d 563
6d8df534 564 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 565
43c9dae1 566 // if fConstraint=kFALSE, during iterations 1 and 2 ||
567 // if fConstraint=kTRUE, during iteration 2,
fee9ef0d 568 // select tracks with d0oplusz0 < maxd0z0
43c9dae1 569 if((!fConstraint && optImpParCut>0 && fVert.GetNContributors()>0) ||
570 ( fConstraint && optImpParCut==2)) {
571 if(nTrksOrig>=3 &&
572 TMath::Sqrt(d0z0[0]*d0z0[0]+d0z0[1]*d0z0[1])>maxd0z0) {
fee9ef0d 573 if(fDebug) printf(" rejected\n");
574 delete track; continue;
575 }
576 }
43c9dae1 577
fee9ef0d 578
579 // select tracks with d0rphi < maxd0rphi
6d8df534 580 if(optImpParCut>0 && TMath::Abs(d0z0[0])>maxd0rphi) {
50ff0bcd 581 if(fDebug) printf(" rejected\n");
582 delete track; continue;
583 }
584
6d8df534 585 fTrkArraySel.AddLast(track);
586 fIdSel[nTrksSel] = idOrig[i];
587 nTrksSel++;
50ff0bcd 588 }
589
590 delete initVertex;
591
6d8df534 592 return nTrksSel;
50ff0bcd 593}
594//---------------------------------------------------------------------------
fee9ef0d 595AliESDVertex* AliVertexerTracks::RemoveTracksFromVertex(AliESDVertex *inVtx,
6d8df534 596 TObjArray *trkArray,
597 UShort_t *id,
fee9ef0d 598 Float_t *diamondxy)
599{
50ff0bcd 600//
fee9ef0d 601// Removes tracks in trksTree from fit of inVtx
50ff0bcd 602//
fee9ef0d 603
146c29df 604 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraint")) {
605 printf("ERROR: primary vertex has no constraint: cannot remove tracks\n");
606 return 0x0;
607 }
fee9ef0d 608 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraintOnlyFitter"))
609 printf("WARNING: result of tracks' removal will be only approximately correct\n");
610
611 TMatrixD rv(3,1);
612 rv(0,0) = inVtx->GetXv();
613 rv(1,0) = inVtx->GetYv();
614 rv(2,0) = inVtx->GetZv();
615 TMatrixD vV(3,3);
616 Double_t cov[6];
617 inVtx->GetCovMatrix(cov);
618 vV(0,0) = cov[0];
619 vV(0,1) = cov[1]; vV(1,0) = cov[1];
620 vV(1,1) = cov[2];
621 vV(0,2) = cov[3]; vV(2,0) = cov[3];
622 vV(1,2) = cov[4]; vV(2,1) = cov[4];
623 vV(2,2) = cov[5];
624
625 TMatrixD sumWi(TMatrixD::kInverted,vV);
626 TMatrixD sumWiri(sumWi,TMatrixD::kMult,rv);
627
dad616ce 628 Int_t nUsedTrks = inVtx->GetNIndices();
fee9ef0d 629 Double_t chi2 = inVtx->GetChi2();
630
6d8df534 631 AliExternalTrackParam *track = 0;
632 Int_t ntrks = (Int_t)trkArray->GetEntriesFast();
fee9ef0d 633 for(Int_t i=0;i<ntrks;i++) {
6d8df534 634 track = (AliExternalTrackParam*)trkArray->At(i);
635 if(!inVtx->UsesTrack(id[i])) {
636 printf("track %d was not used in vertex fit\n",id[i]);
fee9ef0d 637 continue;
638 }
639 Double_t alpha = track->GetAlpha();
640 Double_t xl = diamondxy[0]*TMath::Cos(alpha)+diamondxy[1]*TMath::Sin(alpha);
6d8df534 641 track->PropagateTo(xl,GetFieldkG());
fee9ef0d 642 // vector of track global coordinates
643 TMatrixD ri(3,1);
644 // covariance matrix of ri
645 TMatrixD wWi(3,3);
646
647 // get space point from track
648 if(!TrackToPoint(track,ri,wWi)) continue;
649
650 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
651
652 sumWi -= wWi;
653 sumWiri -= wWiri;
654
655 // track chi2
656 TMatrixD deltar = rv; deltar -= ri;
657 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
658 Double_t chi2i = deltar(0,0)*wWideltar(0,0)+
659 deltar(1,0)*wWideltar(1,0)+
660 deltar(2,0)*wWideltar(2,0);
661 // remove from total chi2
662 chi2 -= chi2i;
663
664 nUsedTrks--;
665 if(nUsedTrks<2) {
666 printf("Trying to remove too many tracks!\n");
667 return 0x0;
668 }
669 }
670
671 TMatrixD rvnew(3,1);
672 TMatrixD vVnew(3,3);
673
674 // new inverted of weights matrix
675 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
676 vVnew = invsumWi;
677 // new position of primary vertex
678 rvnew.Mult(vVnew,sumWiri);
679
680 Double_t position[3];
681 position[0] = rvnew(0,0);
682 position[1] = rvnew(1,0);
683 position[2] = rvnew(2,0);
684 cov[0] = vVnew(0,0);
685 cov[1] = vVnew(0,1);
686 cov[2] = vVnew(1,1);
687 cov[3] = vVnew(0,2);
688 cov[4] = vVnew(1,2);
689 cov[5] = vVnew(2,2);
690
691 // store data in the vertex object
692 AliESDVertex *outVtx = new AliESDVertex(position,cov,chi2,nUsedTrks);
693 outVtx->SetTitle(inVtx->GetTitle());
fee9ef0d 694 UShort_t *inindices = inVtx->GetIndices();
dad616ce 695 Int_t nIndices = nUsedTrks;
4d023a8f 696 UShort_t *outindices = new UShort_t[nIndices];
fee9ef0d 697 Int_t j=0;
fee9ef0d 698 for(Int_t k=0; k<inVtx->GetNIndices(); k++) {
6d8df534 699 Bool_t copyindex=kTRUE;
fee9ef0d 700 for(Int_t l=0; l<ntrks; l++) {
6d8df534 701 if(inindices[k]==id[l]) copyindex=kFALSE;
fee9ef0d 702 }
703 if(copyindex) {
704 outindices[j] = inindices[k]; j++;
705 }
706 }
4d023a8f 707 outVtx->SetIndices(nIndices,outindices);
fee9ef0d 708 delete [] outindices;
709
710 if(fDebug) {
711 printf("Vertex before removing tracks:\n");
712 inVtx->PrintStatus();
713 inVtx->PrintIndices();
714 printf("Vertex after removing tracks:\n");
715 outVtx->PrintStatus();
716 outVtx->PrintIndices();
717 }
718
719 return outVtx;
720}
721//---------------------------------------------------------------------------
722void AliVertexerTracks::SetSkipTracks(Int_t n,Int_t *skipped)
723{
724//
725// Mark the tracks not to be used in the vertex reconstruction.
726// Tracks are identified by AliESDtrack::GetID()
727//
728 fNTrksToSkip = n; fTrksToSkip = new Int_t[n];
50ff0bcd 729 for(Int_t i=0;i<n;i++) fTrksToSkip[i] = skipped[i];
730 return;
731}
732//---------------------------------------------------------------------------
fee9ef0d 733void AliVertexerTracks::SetVtxStart(AliESDVertex *vtx)
734{
50ff0bcd 735//
736// Set initial vertex knowledge
737//
738 vtx->GetXYZ(fNominalPos);
739 vtx->GetCovMatrix(fNominalCov);
fee9ef0d 740 SetConstraintOn();
50ff0bcd 741 return;
742}
2d57349e 743//---------------------------------------------------------------------------
fee9ef0d 744void AliVertexerTracks::StrLinVertexFinderMinDist(Int_t optUseWeights)
dc3719f3 745{
6d8df534 746 AliExternalTrackParam *track1;
dc3719f3 747 Double_t field=GetFieldkG();
6d8df534 748 const Int_t knacc = (Int_t)fTrkArraySel.GetEntriesFast();
dc3719f3 749 TClonesArray *linarray = new TClonesArray("AliStrLine",1000);
750 TClonesArray &lines = *linarray;
751 for(Int_t i=0; i<knacc; i++){
6d8df534 752 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
dc3719f3 753 Double_t alpha=track1->GetAlpha();
754 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
755 Double_t pos[3],dir[3],sigmasq[3];
756 track1->GetXYZAt(mindist,field,pos);
757 track1->GetPxPyPzAt(mindist,field,dir);
758 sigmasq[0]=TMath::Sin(alpha)*TMath::Sin(alpha)*track1->GetSigmaY2();
759 sigmasq[1]=TMath::Cos(alpha)*TMath::Cos(alpha)*track1->GetSigmaY2();
760 sigmasq[2]=track1->GetSigmaZ2();
146c29df 761 TMatrixD ri(3,1);
762 TMatrixD wWi(3,3);
763 if(!TrackToPoint(track1,ri,wWi)) continue;
764 Double_t wmat[9];
765 Int_t iel=0;
766 for(Int_t ia=0;ia<3;ia++){
767 for(Int_t ib=0;ib<3;ib++){
768 wmat[iel]=wWi(ia,ib);
769 iel++;
770 }
771 }
772 new(lines[i]) AliStrLine(pos,sigmasq,wmat,dir);
dc3719f3 773 }
774 fVert=TrackletVertexFinder(linarray,optUseWeights);
775 linarray->Delete();
776 delete linarray;
777}
778//---------------------------------------------------------------------------
146c29df 779AliESDVertex AliVertexerTracks::TrackletVertexFinder(TClonesArray *lines, Int_t optUseWeights)
fee9ef0d 780{
2d57349e 781 // Calculate the point at minimum distance to prepared tracks
782
dc3719f3 783 const Int_t knacc = (Int_t)lines->GetEntriesFast();
784 Double_t initPos[3]={0.,0.,0.};
2d57349e 785
2d57349e 786 Double_t (*vectP0)[3]=new Double_t [knacc][3];
787 Double_t (*vectP1)[3]=new Double_t [knacc][3];
788
789 Double_t sum[3][3];
790 Double_t dsum[3]={0,0,0};
146c29df 791 TMatrixD sumWi(3,3);
792 for(Int_t i=0;i<3;i++){
793 for(Int_t j=0;j<3;j++){
794 sum[i][j]=0;
795 sumWi(i,j)=0.;
796 }
797 }
798
2d57349e 799 for(Int_t i=0; i<knacc; i++){
dc3719f3 800 AliStrLine* line1 = (AliStrLine*)lines->At(i);
801 Double_t p0[3],cd[3],sigmasq[3];
146c29df 802 Double_t wmat[9];
2d57349e 803 line1->GetP0(p0);
804 line1->GetCd(cd);
dc3719f3 805 line1->GetSigma2P0(sigmasq);
146c29df 806 line1->GetWMatrix(wmat);
807 TMatrixD wWi(3,3);
808 Int_t iel=0;
809 for(Int_t ia=0;ia<3;ia++){
810 for(Int_t ib=0;ib<3;ib++){
811 wWi(ia,ib)=wmat[iel];
812 iel++;
813 }
814 }
815
816 sumWi+=wWi;
817
2d57349e 818 Double_t p1[3]={p0[0]+cd[0],p0[1]+cd[1],p0[2]+cd[2]};
819 vectP0[i][0]=p0[0];
820 vectP0[i][1]=p0[1];
821 vectP0[i][2]=p0[2];
822 vectP1[i][0]=p1[0];
823 vectP1[i][1]=p1[1];
824 vectP1[i][2]=p1[2];
825
826 Double_t matr[3][3];
827 Double_t dknow[3];
828 if(optUseWeights==0)GetStrLinDerivMatrix(p0,p1,matr,dknow);
dc3719f3 829 else GetStrLinDerivMatrix(p0,p1,sigmasq,matr,dknow);
830
2d57349e 831
832 for(Int_t iii=0;iii<3;iii++){
833 dsum[iii]+=dknow[iii];
834 for(Int_t lj=0;lj<3;lj++) sum[iii][lj]+=matr[iii][lj];
835 }
2d57349e 836 }
146c29df 837
838 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
839 Double_t covmatrix[6];
840 covmatrix[0] = invsumWi(0,0);
841 covmatrix[1] = invsumWi(0,1);
842 covmatrix[2] = invsumWi(1,1);
843 covmatrix[3] = invsumWi(0,2);
844 covmatrix[4] = invsumWi(1,2);
845 covmatrix[5] = invsumWi(2,2);
846
2d57349e 847 Double_t vett[3][3];
848 Double_t det=GetDeterminant3X3(sum);
dc3719f3 849 Double_t sigma=0;
2d57349e 850
fee9ef0d 851 if(det!=0){
852 for(Int_t zz=0;zz<3;zz++){
853 for(Int_t ww=0;ww<3;ww++){
854 for(Int_t kk=0;kk<3;kk++) vett[ww][kk]=sum[ww][kk];
855 }
856 for(Int_t kk=0;kk<3;kk++) vett[kk][zz]=dsum[kk];
857 initPos[zz]=GetDeterminant3X3(vett)/det;
858 }
859
860
861 for(Int_t i=0; i<knacc; i++){
862 Double_t p0[3]={0,0,0},p1[3]={0,0,0};
863 for(Int_t ii=0;ii<3;ii++){
864 p0[ii]=vectP0[i][ii];
865 p1[ii]=vectP1[i][ii];
866 }
867 sigma+=GetStrLinMinDist(p0,p1,initPos);
868 }
869
870 sigma=TMath::Sqrt(sigma);
871 }else{
50ff0bcd 872 sigma=999;
873 }
146c29df 874 AliESDVertex theVert(initPos,covmatrix,99999.,knacc);
875 theVert.SetDispersion(sigma);
50ff0bcd 876 delete vectP0;
877 delete vectP1;
dc3719f3 878 return theVert;
50ff0bcd 879}
880//---------------------------------------------------------------------------
6d8df534 881Bool_t AliVertexerTracks::TrackToPoint(AliExternalTrackParam *t,
0bf2e2b4 882 TMatrixD &ri,TMatrixD &wWi,
883 Bool_t uUi3by3) const
fee9ef0d 884{
885//
6d8df534 886// Extract from the AliExternalTrackParam the global coordinates ri and covariance matrix
fee9ef0d 887// wWi of the space point that it represents (to be used in VertexFitter())
888//
889
890
891 Double_t rotAngle = t->GetAlpha();
892 if(rotAngle<0.) rotAngle += 2.*TMath::Pi();
893 Double_t cosRot = TMath::Cos(rotAngle);
894 Double_t sinRot = TMath::Sin(rotAngle);
895
896 ri(0,0) = t->GetX()*cosRot-t->GetY()*sinRot;
897 ri(1,0) = t->GetX()*sinRot+t->GetY()*cosRot;
898 ri(2,0) = t->GetZ();
899
0bf2e2b4 900
901
902 if(!uUi3by3) {
903 // matrix to go from global (x,y,z) to local (y,z);
904 TMatrixD qQi(2,3);
905 qQi(0,0) = -sinRot;
906 qQi(0,1) = cosRot;
907 qQi(0,2) = 0.;
908 qQi(1,0) = 0.;
909 qQi(1,1) = 0.;
910 qQi(1,2) = 1.;
911
912 // covariance matrix of local (y,z) - inverted
0bf2e2b4 913 TMatrixD uUi(2,2);
6d8df534 914 uUi(0,0) = t->GetSigmaY2();
915 uUi(0,1) = t->GetSigmaZY();
916 uUi(1,0) = t->GetSigmaZY();
917 uUi(1,1) = t->GetSigmaZ2();
0bf2e2b4 918 //printf(" Ui :\n");
919 //printf(" %f %f\n",uUi(0,0),uUi(0,1));
920 //printf(" %f %f\n",uUi(1,0),uUi(1,1));
921
922 if(uUi.Determinant() <= 0.) return kFALSE;
923 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
924
925 // weights matrix: wWi = qQiT * uUiInv * qQi
926 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
927 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
928 wWi = m;
929 } else {
930 if(fVert.GetNContributors()<1) AliFatal("Vertex from finder is empty");
931 // matrix to go from global (x,y,z) to local (x,y,z);
932 TMatrixD qQi(3,3);
933 qQi(0,0) = cosRot;
934 qQi(0,1) = sinRot;
935 qQi(0,2) = 0.;
936 qQi(1,0) = -sinRot;
937 qQi(1,1) = cosRot;
938 qQi(1,2) = 0.;
939 qQi(2,0) = 0.;
940 qQi(2,1) = 0.;
941 qQi(2,2) = 1.;
942
943 // covariance of fVert along the track
944 Double_t p[3],pt,ptot;
945 t->GetPxPyPz(p);
946 pt = TMath::Sqrt(p[0]*p[0]+p[1]*p[1]);
947 ptot = TMath::Sqrt(pt*pt+p[2]*p[2]);
3b768a1d 948 Double_t cphi = p[0]/pt; //cos(phi)=px/pt
949 Double_t sphi = p[1]/pt; //sin(phi)=py/pt
950 Double_t clambda = pt/ptot; //cos(lambda)=pt/ptot
951 Double_t slambda = p[2]/ptot; //sin(lambda)=pz/ptot
0bf2e2b4 952 Double_t covfVert[6];
953 fVert.GetCovMatrix(covfVert);
954 Double_t covfVertalongt =
3b768a1d 955 covfVert[0]*cphi*cphi*clambda*clambda
956 +covfVert[1]*2.*cphi*sphi*clambda*clambda
957 +covfVert[3]*2.*cphi*clambda*slambda
958 +covfVert[2]*sphi*sphi*clambda*clambda
959 +covfVert[4]*2.*sphi*clambda*slambda
960 +covfVert[5]*slambda*slambda;
0bf2e2b4 961 // covariance matrix of local (x,y,z) - inverted
962 TMatrixD uUi(3,3);
3b768a1d 963 uUi(0,0) = covfVertalongt * fnSigmaForUi00 * fnSigmaForUi00;
0bf2e2b4 964 if(fDebug) printf("=====> sqrtUi00 cm %f\n",TMath::Sqrt(uUi(0,0)));
965 uUi(0,1) = 0.;
966 uUi(0,2) = 0.;
967 uUi(1,0) = 0.;
6d8df534 968 uUi(1,1) = t->GetSigmaY2();
969 uUi(1,2) = t->GetSigmaZY();
0bf2e2b4 970 uUi(2,0) = 0.;
6d8df534 971 uUi(2,1) = t->GetSigmaZY();
972 uUi(2,2) = t->GetSigmaZ2();
0bf2e2b4 973 //printf(" Ui :\n");
974 //printf(" %f %f\n",uUi(0,0),uUi(0,1));
975 //printf(" %f %f\n",uUi(1,0),uUi(1,1));
fee9ef0d 976
0bf2e2b4 977 if(uUi.Determinant() <= 0.) return kFALSE;
978 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
979
980 // weights matrix: wWi = qQiT * uUiInv * qQi
981 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
982 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
983 wWi = m;
984 }
985
fee9ef0d 986
987 return kTRUE;
988}
989//---------------------------------------------------------------------------
6d8df534 990void AliVertexerTracks::TooFewTracks()
fee9ef0d 991{
50ff0bcd 992//
6d8df534 993// When the number of tracks is < fMinTracks,
994// deal with vertices not found and prepare to exit
50ff0bcd 995//
6d8df534 996 if(fDebug) printf("TooFewTracks\n");
2d57349e 997
50ff0bcd 998 Double_t pos[3],err[3];
50ff0bcd 999 pos[0] = fNominalPos[0];
1000 err[0] = TMath::Sqrt(fNominalCov[0]);
1001 pos[1] = fNominalPos[1];
1002 err[1] = TMath::Sqrt(fNominalCov[2]);
6d8df534 1003 pos[2] = fNominalPos[2];
1004 err[2] = TMath::Sqrt(fNominalCov[5]);
1005 Int_t ncontr = (err[0]>1. ? -1 : -3);
50ff0bcd 1006 fCurrentVertex = 0;
1007 fCurrentVertex = new AliESDVertex(pos,err);
1008 fCurrentVertex->SetNContributors(ncontr);
2d57349e 1009
fee9ef0d 1010 if(fConstraint) {
1011 fCurrentVertex->SetTitle("VertexerTracksWithConstraint");
1012 } else {
50ff0bcd 1013 fCurrentVertex->SetTitle("VertexerTracksNoConstraint");
fee9ef0d 1014 }
2d57349e 1015
6d8df534 1016 if(!fTrkArraySel.IsEmpty()) fTrkArraySel.Delete();
1017 if(fIdSel) {delete [] fIdSel; fIdSel=NULL;}
1018 if(fTrksToSkip) {delete [] fTrksToSkip; fTrksToSkip=NULL;}
1019
50ff0bcd 1020 return;
1021}
1022//---------------------------------------------------------------------------
fee9ef0d 1023void AliVertexerTracks::VertexFinder(Int_t optUseWeights)
1024{
2d57349e 1025
50ff0bcd 1026 // Get estimate of vertex position in (x,y) from tracks DCA
1027
1028 Double_t initPos[3];
1029 initPos[2] = 0.;
1030 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
6d8df534 1031 Int_t nacc = (Int_t)fTrkArraySel.GetEntriesFast();
50ff0bcd 1032 Double_t aver[3]={0.,0.,0.};
1033 Double_t aversq[3]={0.,0.,0.};
1034 Double_t sigmasq[3]={0.,0.,0.};
1035 Double_t sigma=0;
1036 Int_t ncombi = 0;
6d8df534 1037 AliExternalTrackParam *track1;
1038 AliExternalTrackParam *track2;
50ff0bcd 1039 Double_t pos[3],dir[3];
1040 Double_t alpha,mindist;
dc3719f3 1041 Double_t field=GetFieldkG();
2d57349e 1042
50ff0bcd 1043 for(Int_t i=0; i<nacc; i++){
6d8df534 1044 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
50ff0bcd 1045 alpha=track1->GetAlpha();
1046 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1047 track1->GetXYZAt(mindist,field,pos);
1048 track1->GetPxPyPzAt(mindist,field,dir);
1049 AliStrLine *line1 = new AliStrLine(pos,dir);
2d57349e 1050
50ff0bcd 1051 // AliStrLine *line1 = new AliStrLine();
1052 // track1->ApproximateHelixWithLine(mindist,field,line1);
1053
1054 for(Int_t j=i+1; j<nacc; j++){
6d8df534 1055 track2 = (AliExternalTrackParam*)fTrkArraySel.At(j);
50ff0bcd 1056 alpha=track2->GetAlpha();
1057 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1058 track2->GetXYZAt(mindist,field,pos);
1059 track2->GetPxPyPzAt(mindist,field,dir);
1060 AliStrLine *line2 = new AliStrLine(pos,dir);
1061 // AliStrLine *line2 = new AliStrLine();
1062 // track2->ApproximateHelixWithLine(mindist,field,line2);
1063 Double_t distCA=line2->GetDCA(line1);
fee9ef0d 1064 //printf("%d %d %f\n",i,j,distCA);
1065 if(fDCAcut<=0 || (fDCAcut>0&&distCA<fDCAcut)){
50ff0bcd 1066 Double_t pnt1[3],pnt2[3],crosspoint[3];
2d57349e 1067
50ff0bcd 1068 if(optUseWeights<=0){
1069 Int_t retcode = line2->Cross(line1,crosspoint);
1070 if(retcode>=0){
1071 ncombi++;
1072 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
1073 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1074 }
1075 }
1076 if(optUseWeights>0){
1077 Int_t retcode = line1->CrossPoints(line2,pnt1,pnt2);
1078 if(retcode>=0){
5c03260f 1079 Double_t cs, sn;
50ff0bcd 1080 alpha=track1->GetAlpha();
1081 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
1082 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
1083 alpha=track2->GetAlpha();
1084 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
1085 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
1086 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
1087 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
1088 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
1089 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
1090 crosspoint[0]=wx1*pnt1[0] + wx2*pnt2[0];
1091 crosspoint[1]=wy1*pnt1[1] + wy2*pnt2[1];
1092 crosspoint[2]=wz1*pnt1[2] + wz2*pnt2[2];
1093
1094 ncombi++;
1095 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
1096 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1097 }
1098 }
1099 }
1100 delete line2;
1101 }
1102 delete line1;
71d84967 1103 }
50ff0bcd 1104 if(ncombi>0){
1105 for(Int_t jj=0;jj<3;jj++){
1106 initPos[jj] = aver[jj]/ncombi;
fee9ef0d 1107 //printf("%f\n",initPos[jj]);
50ff0bcd 1108 aversq[jj]/=ncombi;
1109 sigmasq[jj]=aversq[jj]-initPos[jj]*initPos[jj];
1110 sigma+=sigmasq[jj];
1111 }
1112 sigma=TMath::Sqrt(TMath::Abs(sigma));
1113 }
1114 else {
1115 Warning("VertexFinder","Finder did not succed");
1116 sigma=999;
1117 }
1118 fVert.SetXYZ(initPos);
1119 fVert.SetDispersion(sigma);
1120 fVert.SetNContributors(ncombi);
2d57349e 1121}
ec1be5d5 1122//---------------------------------------------------------------------------
6d8df534 1123void AliVertexerTracks::VertexFitter()
fee9ef0d 1124{
ec1be5d5 1125//
1126// The optimal estimate of the vertex position is given by a "weighted
0bf2e2b4 1127// average of tracks positions".
fee9ef0d 1128// Original method: V. Karimaki, CMS Note 97/0051
ec1be5d5 1129//
6d8df534 1130 Bool_t useConstraint = fConstraint;
ec1be5d5 1131 Double_t initPos[3];
0bf2e2b4 1132 if(!fOnlyFitter) {
1133 fVert.GetXYZ(initPos);
1134 } else {
1135 initPos[0]=fNominalPos[0];
1136 initPos[1]=fNominalPos[1];
1137 initPos[2]=fNominalPos[2];
1138 }
1139
6d8df534 1140 Int_t nTrksSel = (Int_t)fTrkArraySel.GetEntries();
1141 if(nTrksSel==1) useConstraint=kTRUE;
ec1be5d5 1142 if(fDebug) {
0bf2e2b4 1143 printf("--- VertexFitter(): start\n");
6d8df534 1144 printf(" Number of tracks in array: %d\n",nTrksSel);
ec1be5d5 1145 printf(" Minimum # tracks required in fit: %d\n",fMinTracks);
3b768a1d 1146 printf(" Vertex position after finder: %f,%f,%f\n",initPos[0],initPos[1],initPos[2]);
fee9ef0d 1147 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 1148 }
1149
0bf2e2b4 1150 // special treatment for few-tracks fits (e.g. secondary vertices)
6d8df534 1151 Bool_t uUi3by3 = kFALSE; if(nTrksSel<5 && !useConstraint) uUi3by3 = kTRUE;
0bf2e2b4 1152
ec1be5d5 1153 Int_t i,j,k,step=0;
1154 TMatrixD rv(3,1);
1155 TMatrixD vV(3,3);
1156 rv(0,0) = initPos[0];
1157 rv(1,0) = initPos[1];
1158 rv(2,0) = 0.;
1159 Double_t xlStart,alpha;
6d8df534 1160 Int_t nTrksUsed;
fee9ef0d 1161 Double_t chi2,chi2i,chi2b;
6d8df534 1162 AliExternalTrackParam *t = 0;
ec1be5d5 1163 Int_t failed = 0;
1164
50ff0bcd 1165 // initial vertex covariance matrix
1166 TMatrixD vVb(3,3);
1167 vVb(0,0) = fNominalCov[0];
1168 vVb(0,1) = fNominalCov[1];
1169 vVb(0,2) = 0.;
1170 vVb(1,0) = fNominalCov[1];
1171 vVb(1,1) = fNominalCov[2];
1172 vVb(1,2) = 0.;
1173 vVb(2,0) = 0.;
1174 vVb(2,1) = 0.;
1175 vVb(2,2) = fNominalCov[5];
1176 TMatrixD vVbInv(TMatrixD::kInverted,vVb);
1177 TMatrixD rb(3,1);
1178 rb(0,0) = fNominalPos[0];
1179 rb(1,0) = fNominalPos[1];
1180 rb(2,0) = fNominalPos[2];
1181 TMatrixD vVbInvrb(vVbInv,TMatrixD::kMult,rb);
1182
1183
eae1677e 1184 // 2 steps:
1185 // 1st - estimate of vtx using all tracks
1186 // 2nd - estimate of global chi2
1187 for(step=0; step<2; step++) {
ec1be5d5 1188 if(fDebug) printf(" step = %d\n",step);
1189 chi2 = 0.;
6d8df534 1190 nTrksUsed = 0;
ec1be5d5 1191
0bf2e2b4 1192 if(step==1) { initPos[0]=rv(0,0); initPos[0]=rv(1,0); }
1193
ec1be5d5 1194 TMatrixD sumWiri(3,1);
1195 TMatrixD sumWi(3,3);
1196 for(i=0; i<3; i++) {
1197 sumWiri(i,0) = 0.;
1198 for(j=0; j<3; j++) sumWi(j,i) = 0.;
1199 }
1200
fee9ef0d 1201 // mean vertex constraint
1202 if(useConstraint) {
50ff0bcd 1203 for(i=0;i<3;i++) {
1204 sumWiri(i,0) += vVbInvrb(i,0);
1205 for(k=0;k<3;k++) sumWi(i,k) += vVbInv(i,k);
07680cae 1206 }
fee9ef0d 1207 // chi2
1208 TMatrixD deltar = rv; deltar -= rb;
1209 TMatrixD vVbInvdeltar(vVbInv,TMatrixD::kMult,deltar);
1210 chi2b = deltar(0,0)*vVbInvdeltar(0,0)+
1211 deltar(1,0)*vVbInvdeltar(1,0)+
1212 deltar(2,0)*vVbInvdeltar(2,0);
1213 chi2 += chi2b;
07680cae 1214 }
1215
ec1be5d5 1216 // loop on tracks
6d8df534 1217 for(k=0; k<nTrksSel; k++) {
ec1be5d5 1218 // get track from track array
6d8df534 1219 t = (AliExternalTrackParam*)fTrkArraySel.At(k);
ec1be5d5 1220 alpha = t->GetAlpha();
1221 xlStart = initPos[0]*TMath::Cos(alpha)+initPos[1]*TMath::Sin(alpha);
fee9ef0d 1222 // to vtxSeed (from finder)
6d8df534 1223 t->PropagateTo(xlStart,GetFieldkG());
fee9ef0d 1224
ec1be5d5 1225 // vector of track global coordinates
1226 TMatrixD ri(3,1);
fee9ef0d 1227 // covariance matrix of ri
1228 TMatrixD wWi(3,3);
1229
1230 // get space point from track
0bf2e2b4 1231 if(!TrackToPoint(t,ri,wWi,uUi3by3)) continue;
fee9ef0d 1232 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
ec1be5d5 1233
1234 // track chi2
1235 TMatrixD deltar = rv; deltar -= ri;
1236 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
1237 chi2i = deltar(0,0)*wWideltar(0,0)+
1238 deltar(1,0)*wWideltar(1,0)+
1239 deltar(2,0)*wWideltar(2,0);
1240
ec1be5d5 1241 // add to total chi2
1242 chi2 += chi2i;
1243
ec1be5d5 1244 sumWiri += wWiri;
1245 sumWi += wWi;
1246
6d8df534 1247 nTrksUsed++;
ec1be5d5 1248 } // end loop on tracks
1249
6d8df534 1250 if(nTrksUsed < fMinTracks) {
ec1be5d5 1251 failed=1;
1252 continue;
1253 }
1254
1255 Double_t determinant = sumWi.Determinant();
1256 //cerr<<" determinant: "<<determinant<<endl;
1257 if(determinant < 100.) {
1258 printf("det(V) = 0\n");
1259 failed=1;
1260 continue;
1261 }
1262
0bf2e2b4 1263 if(step==0) {
1264 // inverted of weights matrix
1265 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
1266 vV = invsumWi;
1267 // position of primary vertex
1268 rv.Mult(vV,sumWiri);
1269 }
eae1677e 1270 } // end loop on the 2 steps
ec1be5d5 1271
ec1be5d5 1272 if(failed) {
6d8df534 1273 TooFewTracks();
ec1be5d5 1274 return;
1275 }
1276
1277 Double_t position[3];
1278 position[0] = rv(0,0);
1279 position[1] = rv(1,0);
1280 position[2] = rv(2,0);
1281 Double_t covmatrix[6];
1282 covmatrix[0] = vV(0,0);
1283 covmatrix[1] = vV(0,1);
1284 covmatrix[2] = vV(1,1);
1285 covmatrix[3] = vV(0,2);
1286 covmatrix[4] = vV(1,2);
1287 covmatrix[5] = vV(2,2);
1288
dc3719f3 1289 // for correct chi2/ndf, count constraint as additional "track"
6d8df534 1290 if(fConstraint) nTrksUsed++;
ec1be5d5 1291 // store data in the vertex object
6d8df534 1292 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nTrksUsed);
ec1be5d5 1293
1294 if(fDebug) {
0bf2e2b4 1295 printf(" Vertex after fit:\n");
ec1be5d5 1296 fCurrentVertex->PrintStatus();
0bf2e2b4 1297 printf("--- VertexFitter(): finish\n");
ec1be5d5 1298 }
1299
1300 return;
1301}
50ff0bcd 1302//----------------------------------------------------------------------------
6d8df534 1303AliESDVertex* AliVertexerTracks::VertexForSelectedTracks(TObjArray *trkArray,
1304 UShort_t *id,
1305 Bool_t optUseFitter,
1306 Bool_t optPropagate)
fee9ef0d 1307{
eae1677e 1308//
6d8df534 1309// Return vertex from tracks (AliExternalTrackParam) in array
eae1677e 1310//
1311
fee9ef0d 1312 SetConstraintOff();
1313
50ff0bcd 1314 // get tracks and propagate them to initial vertex position
6d8df534 1315 fIdSel = new UShort_t[(Int_t)trkArray->GetEntriesFast()];
1316 Int_t nTrksSel = PrepareTracks(*trkArray,id,0);
1317 if(nTrksSel < TMath::Max(2,fMinTracks)) {
1318 TooFewTracks();
fee9ef0d 1319 return fCurrentVertex;
50ff0bcd 1320 }
1321
6d8df534 1322 // vertex finder
fee9ef0d 1323 switch (fAlgo) {
1324 case 1: StrLinVertexFinderMinDist(1); break;
1325 case 2: StrLinVertexFinderMinDist(0); break;
1326 case 3: HelixVertexFinder(); break;
1327 case 4: VertexFinder(1); break;
1328 case 5: VertexFinder(0); break;
1329 default: printf("Wrong algorithm\n"); break;
1330 }
fee9ef0d 1331 if(fDebug) printf(" Vertex finding completed\n");
1332
1333 // vertex fitter
6d8df534 1334 if(optUseFitter) {
1335 VertexFitter();
1336 } else {
fee9ef0d 1337 Double_t position[3]={fVert.GetXv(),fVert.GetYv(),fVert.GetZv()};
146c29df 1338 Double_t covmatrix[6];
1339 fVert.GetCovMatrix(covmatrix);
fee9ef0d 1340 Double_t chi2=99999.;
6d8df534 1341 Int_t nTrksUsed=fVert.GetNContributors();
1342 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nTrksUsed);
fee9ef0d 1343 }
1344 fCurrentVertex->SetDispersion(fVert.GetDispersion());
1345
1346
1347 // set indices of used tracks and propagate track to found vertex
50ff0bcd 1348 UShort_t *indices = 0;
6d8df534 1349 Double_t d0z0[2],covd0z0[3];
1350 AliExternalTrackParam *t = 0;
fee9ef0d 1351 if(fCurrentVertex->GetNContributors()>0) {
1352 indices = new UShort_t[fCurrentVertex->GetNContributors()];
6d8df534 1353 for(Int_t jj=0; jj<(Int_t)fTrkArraySel.GetEntriesFast(); jj++) {
1354 indices[jj] = fIdSel[jj];
1355 t = (AliExternalTrackParam*)fTrkArraySel.At(jj);
1356 if(optPropagate && optUseFitter) {
fee9ef0d 1357 if(TMath::Sqrt(fCurrentVertex->GetXv()*fCurrentVertex->GetXv()+fCurrentVertex->GetYv()*fCurrentVertex->GetYv())<3.) {
6d8df534 1358 t->PropagateToDCA(fCurrentVertex,GetFieldkG(),100.,d0z0,covd0z0);
fee9ef0d 1359 if(fDebug) printf("Track %d propagated to found vertex\n",jj);
6d8df534 1360 } else {
fee9ef0d 1361 AliWarning("Found vertex outside beam pipe!");
1362 }
1363 }
50ff0bcd 1364 }
fee9ef0d 1365 fCurrentVertex->SetIndices(fCurrentVertex->GetNContributors(),indices);
50ff0bcd 1366 }
6d8df534 1367
1368 // clean up
1369 delete [] indices; indices=NULL;
1370 delete [] fIdSel; fIdSel=NULL;
1371 fTrkArraySel.Delete();
50ff0bcd 1372
fee9ef0d 1373 return fCurrentVertex;
eae1677e 1374}
50ff0bcd 1375//----------------------------------------------------------------------------
6d8df534 1376AliESDVertex* AliVertexerTracks::VertexForSelectedESDTracks(TObjArray *trkArray,
1377 Bool_t optUseFitter,
1378 Bool_t optPropagate)
fee9ef0d 1379{
50ff0bcd 1380//
6d8df534 1381// Return vertex from array of ESD tracks
50ff0bcd 1382//
5834e9a1 1383
6d8df534 1384 Int_t nTrks = (Int_t)trkArray->GetEntriesFast();
1385 UShort_t *id = new UShort_t[nTrks];
1386
1387 AliESDtrack *esdt = 0;
50ff0bcd 1388 for(Int_t i=0; i<nTrks; i++){
6d8df534 1389 esdt = (AliESDtrack*)trkArray->At(i);
1390 id[i] = (UShort_t)esdt->GetID();
50ff0bcd 1391 }
1392
6d8df534 1393 VertexForSelectedTracks(trkArray,id,optUseFitter,optPropagate);
1394
1395 delete [] id; id=NULL;
1396
1397 return fCurrentVertex;
50ff0bcd 1398}
1399//--------------------------------------------------------------------------
43c9dae1 1400