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Make use of new method AliRawReader::GetNumberOfEvents() - goinf to the last event...
[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];
3446476f 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);
396
397 return ((y10*z12-z10*y12)*(y10*z12-z10*y12)+
398 (z10*x12-x10*z12)*(z10*x12-x10*z12)+
399 (x10*y12-y10*x12)*(x10*y12-y10*x12))
400 /(x12*x12+y12*y12+z12*z12);
401
2d57349e 402}
403//---------------------------------------------------------------------------
fee9ef0d 404void AliVertexerTracks::OneTrackVertFinder()
405{
0c69be49 406 // find vertex for events with 1 track, using DCA to nominal beam axis
6d8df534 407 if(fDebug) printf("Number of prepared tracks =%d - Call OneTrackVertFinder",fTrkArraySel.GetEntries());
408 AliExternalTrackParam *track1;
409 track1 = (AliExternalTrackParam*)fTrkArraySel.At(0);
dc3719f3 410 Double_t field=GetFieldkG();
0c69be49 411 Double_t alpha=track1->GetAlpha();
412 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
413 Double_t pos[3],dir[3];
414 track1->GetXYZAt(mindist,field,pos);
415 track1->GetPxPyPzAt(mindist,field,dir);
416 AliStrLine *line1 = new AliStrLine(pos,dir);
417 Double_t p1[3]={fNominalPos[0],fNominalPos[1],0.};
418 Double_t p2[3]={fNominalPos[0],fNominalPos[1],10.};
419 AliStrLine *zeta=new AliStrLine(p1,p2,kTRUE);
420 Double_t crosspoint[3]={0.,0.,0.};
421 Double_t sigma=999.;
422 Int_t nContrib=-1;
423 Int_t retcode = zeta->Cross(line1,crosspoint);
424 if(retcode>=0){
425 sigma=line1->GetDistFromPoint(crosspoint);
426 nContrib=1;
427 }
428 delete zeta;
429 delete line1;
430 fVert.SetXYZ(crosspoint);
431 fVert.SetDispersion(sigma);
432 fVert.SetNContributors(nContrib);
433}
434//---------------------------------------------------------------------------
fee9ef0d 435void AliVertexerTracks::HelixVertexFinder()
436{
2d57349e 437 // Get estimate of vertex position in (x,y) from tracks DCA
438
439
440 Double_t initPos[3];
441 initPos[2] = 0.;
442 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
dc3719f3 443 Double_t field=GetFieldkG();
2d57349e 444
6d8df534 445 Int_t nacc = (Int_t)fTrkArraySel.GetEntriesFast();
2d57349e 446
447 Double_t aver[3]={0.,0.,0.};
448 Double_t averquad[3]={0.,0.,0.};
449 Double_t sigmaquad[3]={0.,0.,0.};
450 Double_t sigma=0;
451 Int_t ncombi = 0;
6d8df534 452 AliExternalTrackParam *track1;
453 AliExternalTrackParam *track2;
2d57349e 454 Double_t distCA;
6d8df534 455 Double_t x;
2d57349e 456 Double_t alpha, cs, sn;
457 Double_t crosspoint[3];
458 for(Int_t i=0; i<nacc; i++){
6d8df534 459 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
2d57349e 460
461
462 for(Int_t j=i+1; j<nacc; j++){
6d8df534 463 track2 = (AliExternalTrackParam*)fTrkArraySel.At(j);
2d57349e 464
465 distCA=track2->PropagateToDCA(track1,field);
2d57349e 466 if(fDCAcut<=0 ||(fDCAcut>0&&distCA<fDCAcut)){
6d8df534 467 x=track1->GetX();
2d57349e 468 alpha=track1->GetAlpha();
469 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
6d8df534 470 Double_t x1=x*cs - track1->GetY()*sn;
471 Double_t y1=x*sn + track1->GetY()*cs;
472 Double_t z1=track1->GetZ();
473
2d57349e 474 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
6d8df534 475 x=track2->GetX();
2d57349e 476 alpha=track2->GetAlpha();
477 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
6d8df534 478 Double_t x2=x*cs - track2->GetY()*sn;
479 Double_t y2=x*sn + track2->GetY()*cs;
480 Double_t z2=track2->GetZ();
2d57349e 481 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
482 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
483 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
484 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
485 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
486 crosspoint[0]=wx1*x1 + wx2*x2;
487 crosspoint[1]=wy1*y1 + wy2*y2;
488 crosspoint[2]=wz1*z1 + wz2*z2;
489
490 ncombi++;
491 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
492 for(Int_t jj=0;jj<3;jj++)averquad[jj]+=(crosspoint[jj]*crosspoint[jj]);
493 }
494 }
495
496 }
497 if(ncombi>0){
498 for(Int_t jj=0;jj<3;jj++){
499 initPos[jj] = aver[jj]/ncombi;
500 averquad[jj]/=ncombi;
501 sigmaquad[jj]=averquad[jj]-initPos[jj]*initPos[jj];
502 sigma+=sigmaquad[jj];
503 }
504 sigma=TMath::Sqrt(TMath::Abs(sigma));
505 }
506 else {
507 Warning("HelixVertexFinder","Finder did not succed");
508 sigma=999;
509 }
510 fVert.SetXYZ(initPos);
511 fVert.SetDispersion(sigma);
512 fVert.SetNContributors(ncombi);
513}
50ff0bcd 514//----------------------------------------------------------------------------
6d8df534 515Int_t AliVertexerTracks::PrepareTracks(TObjArray &trkArrayOrig,
516 UShort_t *idOrig,
517 Int_t optImpParCut)
fee9ef0d 518{
50ff0bcd 519//
520// Propagate tracks to initial vertex position and store them in a TObjArray
521//
6d8df534 522 if(fDebug) printf(" PrepareTracks()\n");
523
524 Int_t nTrksOrig = (Int_t)trkArrayOrig.GetEntriesFast();
525 Int_t nTrksSel = 0;
fee9ef0d 526 Double_t maxd0rphi;
43c9dae1 527 Double_t maxd0z0 = (fITSrefit ? fMaxd0z0 : 10.*fMaxd0z0);
50ff0bcd 528 Double_t sigmaCurr[3];
fee9ef0d 529 Double_t normdistx,normdisty;
6d8df534 530 Double_t d0z0[2],covd0z0[3];
43c9dae1 531 Double_t sigmad0;
6d8df534 532 Double_t field = GetFieldkG();
50ff0bcd 533
534 AliESDVertex *initVertex = new AliESDVertex(fNominalPos,fNominalCov,1,1);
535
6d8df534 536 if(!fTrkArraySel.IsEmpty()) fTrkArraySel.Delete();
50ff0bcd 537
6d8df534 538 AliExternalTrackParam *track=0;
50ff0bcd 539
6d8df534 540 for(Int_t i=0; i<nTrksOrig; i++) {
541 track = new AliExternalTrackParam(*(AliExternalTrackParam*)trkArrayOrig.At(i));
542 // only TPC tracks in |eta|<0.9
543 if(!fITSrefit && TMath::Abs(track->GetTgl())>1.) {
43c9dae1 544 if(fDebug) printf(" rejecting track with tgl = %f\n",track->GetTgl());
6d8df534 545 delete track;
546 continue;
547 }
50ff0bcd 548
549 // propagate track to vertex
43c9dae1 550 if(optImpParCut<2 || fOnlyFitter) { // optImpParCut==1 or 0
6d8df534 551 track->PropagateToDCA(initVertex,field,100.,d0z0,covd0z0);
fee9ef0d 552 } else { // optImpParCut==2
50ff0bcd 553 fCurrentVertex->GetSigmaXYZ(sigmaCurr);
fee9ef0d 554 normdistx = TMath::Abs(fCurrentVertex->GetXv()-fNominalPos[0])/TMath::Sqrt(sigmaCurr[0]*sigmaCurr[0]+fNominalCov[0]);
80d36431 555 normdisty = TMath::Abs(fCurrentVertex->GetYv()-fNominalPos[1])/TMath::Sqrt(sigmaCurr[1]*sigmaCurr[1]+fNominalCov[2]);
fee9ef0d 556 if(normdistx < 3. && normdisty < 3. &&
80d36431 557 (sigmaCurr[0]+sigmaCurr[1])<(TMath::Sqrt(fNominalCov[0])+TMath::Sqrt(fNominalCov[2]))) {
6d8df534 558 track->PropagateToDCA(fCurrentVertex,field,100.,d0z0,covd0z0);
50ff0bcd 559 } else {
6d8df534 560 track->PropagateToDCA(initVertex,field,100.,d0z0,covd0z0);
50ff0bcd 561 }
562 }
563
43c9dae1 564 sigmad0 = TMath::Sqrt(covd0z0[0]);
565 maxd0rphi = fNSigma*sigmad0;
fee9ef0d 566 if(optImpParCut==1) maxd0rphi *= 5.;
43c9dae1 567 //sigmad0z0 = TMath::Sqrt(covd0z0[0]+covd0z0[2]); // for future improvement
568 //maxd0z0 = 10.*fNSigma*sigmad0z0;
fee9ef0d 569
6d8df534 570 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 571
43c9dae1 572 // if fConstraint=kFALSE, during iterations 1 and 2 ||
573 // if fConstraint=kTRUE, during iteration 2,
fee9ef0d 574 // select tracks with d0oplusz0 < maxd0z0
43c9dae1 575 if((!fConstraint && optImpParCut>0 && fVert.GetNContributors()>0) ||
576 ( fConstraint && optImpParCut==2)) {
577 if(nTrksOrig>=3 &&
578 TMath::Sqrt(d0z0[0]*d0z0[0]+d0z0[1]*d0z0[1])>maxd0z0) {
fee9ef0d 579 if(fDebug) printf(" rejected\n");
580 delete track; continue;
581 }
582 }
43c9dae1 583
fee9ef0d 584
585 // select tracks with d0rphi < maxd0rphi
6d8df534 586 if(optImpParCut>0 && TMath::Abs(d0z0[0])>maxd0rphi) {
50ff0bcd 587 if(fDebug) printf(" rejected\n");
588 delete track; continue;
589 }
590
6d8df534 591 fTrkArraySel.AddLast(track);
592 fIdSel[nTrksSel] = idOrig[i];
593 nTrksSel++;
50ff0bcd 594 }
595
596 delete initVertex;
597
6d8df534 598 return nTrksSel;
50ff0bcd 599}
600//---------------------------------------------------------------------------
fee9ef0d 601AliESDVertex* AliVertexerTracks::RemoveTracksFromVertex(AliESDVertex *inVtx,
6d8df534 602 TObjArray *trkArray,
603 UShort_t *id,
fee9ef0d 604 Float_t *diamondxy)
605{
50ff0bcd 606//
fee9ef0d 607// Removes tracks in trksTree from fit of inVtx
50ff0bcd 608//
fee9ef0d 609
146c29df 610 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraint")) {
611 printf("ERROR: primary vertex has no constraint: cannot remove tracks\n");
612 return 0x0;
613 }
fee9ef0d 614 if(!strstr(inVtx->GetTitle(),"VertexerTracksWithConstraintOnlyFitter"))
615 printf("WARNING: result of tracks' removal will be only approximately correct\n");
616
617 TMatrixD rv(3,1);
618 rv(0,0) = inVtx->GetXv();
619 rv(1,0) = inVtx->GetYv();
620 rv(2,0) = inVtx->GetZv();
621 TMatrixD vV(3,3);
622 Double_t cov[6];
623 inVtx->GetCovMatrix(cov);
624 vV(0,0) = cov[0];
625 vV(0,1) = cov[1]; vV(1,0) = cov[1];
626 vV(1,1) = cov[2];
627 vV(0,2) = cov[3]; vV(2,0) = cov[3];
628 vV(1,2) = cov[4]; vV(2,1) = cov[4];
629 vV(2,2) = cov[5];
630
631 TMatrixD sumWi(TMatrixD::kInverted,vV);
632 TMatrixD sumWiri(sumWi,TMatrixD::kMult,rv);
633
dad616ce 634 Int_t nUsedTrks = inVtx->GetNIndices();
fee9ef0d 635 Double_t chi2 = inVtx->GetChi2();
636
6d8df534 637 AliExternalTrackParam *track = 0;
638 Int_t ntrks = (Int_t)trkArray->GetEntriesFast();
fee9ef0d 639 for(Int_t i=0;i<ntrks;i++) {
6d8df534 640 track = (AliExternalTrackParam*)trkArray->At(i);
641 if(!inVtx->UsesTrack(id[i])) {
642 printf("track %d was not used in vertex fit\n",id[i]);
fee9ef0d 643 continue;
644 }
645 Double_t alpha = track->GetAlpha();
646 Double_t xl = diamondxy[0]*TMath::Cos(alpha)+diamondxy[1]*TMath::Sin(alpha);
6d8df534 647 track->PropagateTo(xl,GetFieldkG());
fee9ef0d 648 // vector of track global coordinates
649 TMatrixD ri(3,1);
650 // covariance matrix of ri
651 TMatrixD wWi(3,3);
652
653 // get space point from track
654 if(!TrackToPoint(track,ri,wWi)) continue;
655
656 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
657
658 sumWi -= wWi;
659 sumWiri -= wWiri;
660
661 // track chi2
662 TMatrixD deltar = rv; deltar -= ri;
663 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
664 Double_t chi2i = deltar(0,0)*wWideltar(0,0)+
665 deltar(1,0)*wWideltar(1,0)+
666 deltar(2,0)*wWideltar(2,0);
667 // remove from total chi2
668 chi2 -= chi2i;
669
670 nUsedTrks--;
671 if(nUsedTrks<2) {
672 printf("Trying to remove too many tracks!\n");
673 return 0x0;
674 }
675 }
676
677 TMatrixD rvnew(3,1);
678 TMatrixD vVnew(3,3);
679
680 // new inverted of weights matrix
681 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
682 vVnew = invsumWi;
683 // new position of primary vertex
684 rvnew.Mult(vVnew,sumWiri);
685
686 Double_t position[3];
687 position[0] = rvnew(0,0);
688 position[1] = rvnew(1,0);
689 position[2] = rvnew(2,0);
690 cov[0] = vVnew(0,0);
691 cov[1] = vVnew(0,1);
692 cov[2] = vVnew(1,1);
693 cov[3] = vVnew(0,2);
694 cov[4] = vVnew(1,2);
695 cov[5] = vVnew(2,2);
696
697 // store data in the vertex object
698 AliESDVertex *outVtx = new AliESDVertex(position,cov,chi2,nUsedTrks);
699 outVtx->SetTitle(inVtx->GetTitle());
fee9ef0d 700 UShort_t *inindices = inVtx->GetIndices();
dad616ce 701 Int_t nIndices = nUsedTrks;
4d023a8f 702 UShort_t *outindices = new UShort_t[nIndices];
fee9ef0d 703 Int_t j=0;
fee9ef0d 704 for(Int_t k=0; k<inVtx->GetNIndices(); k++) {
6d8df534 705 Bool_t copyindex=kTRUE;
fee9ef0d 706 for(Int_t l=0; l<ntrks; l++) {
6d8df534 707 if(inindices[k]==id[l]) copyindex=kFALSE;
fee9ef0d 708 }
709 if(copyindex) {
710 outindices[j] = inindices[k]; j++;
711 }
712 }
4d023a8f 713 outVtx->SetIndices(nIndices,outindices);
fee9ef0d 714 delete [] outindices;
715
716 if(fDebug) {
717 printf("Vertex before removing tracks:\n");
718 inVtx->PrintStatus();
719 inVtx->PrintIndices();
720 printf("Vertex after removing tracks:\n");
721 outVtx->PrintStatus();
722 outVtx->PrintIndices();
723 }
724
725 return outVtx;
726}
727//---------------------------------------------------------------------------
728void AliVertexerTracks::SetSkipTracks(Int_t n,Int_t *skipped)
729{
730//
731// Mark the tracks not to be used in the vertex reconstruction.
732// Tracks are identified by AliESDtrack::GetID()
733//
734 fNTrksToSkip = n; fTrksToSkip = new Int_t[n];
50ff0bcd 735 for(Int_t i=0;i<n;i++) fTrksToSkip[i] = skipped[i];
736 return;
737}
738//---------------------------------------------------------------------------
fee9ef0d 739void AliVertexerTracks::SetVtxStart(AliESDVertex *vtx)
740{
50ff0bcd 741//
742// Set initial vertex knowledge
743//
744 vtx->GetXYZ(fNominalPos);
745 vtx->GetCovMatrix(fNominalCov);
fee9ef0d 746 SetConstraintOn();
50ff0bcd 747 return;
748}
2d57349e 749//---------------------------------------------------------------------------
fee9ef0d 750void AliVertexerTracks::StrLinVertexFinderMinDist(Int_t optUseWeights)
dc3719f3 751{
6d8df534 752 AliExternalTrackParam *track1;
dc3719f3 753 Double_t field=GetFieldkG();
6d8df534 754 const Int_t knacc = (Int_t)fTrkArraySel.GetEntriesFast();
f54bad66 755 static TClonesArray linarray("AliStrLine",knacc);
dc3719f3 756 for(Int_t i=0; i<knacc; i++){
6d8df534 757 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
dc3719f3 758 Double_t alpha=track1->GetAlpha();
759 Double_t mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
760 Double_t pos[3],dir[3],sigmasq[3];
761 track1->GetXYZAt(mindist,field,pos);
762 track1->GetPxPyPzAt(mindist,field,dir);
763 sigmasq[0]=TMath::Sin(alpha)*TMath::Sin(alpha)*track1->GetSigmaY2();
764 sigmasq[1]=TMath::Cos(alpha)*TMath::Cos(alpha)*track1->GetSigmaY2();
765 sigmasq[2]=track1->GetSigmaZ2();
146c29df 766 TMatrixD ri(3,1);
767 TMatrixD wWi(3,3);
768 if(!TrackToPoint(track1,ri,wWi)) continue;
769 Double_t wmat[9];
770 Int_t iel=0;
771 for(Int_t ia=0;ia<3;ia++){
772 for(Int_t ib=0;ib<3;ib++){
773 wmat[iel]=wWi(ia,ib);
774 iel++;
775 }
776 }
f54bad66 777 new(linarray[i]) AliStrLine(pos,sigmasq,wmat,dir);
dc3719f3 778 }
f54bad66 779 fVert=TrackletVertexFinder(&linarray,optUseWeights);
780 linarray.Clear("C");
dc3719f3 781}
782//---------------------------------------------------------------------------
146c29df 783AliESDVertex AliVertexerTracks::TrackletVertexFinder(TClonesArray *lines, Int_t optUseWeights)
fee9ef0d 784{
2d57349e 785 // Calculate the point at minimum distance to prepared tracks
786
dc3719f3 787 const Int_t knacc = (Int_t)lines->GetEntriesFast();
788 Double_t initPos[3]={0.,0.,0.};
2d57349e 789
2d57349e 790 Double_t (*vectP0)[3]=new Double_t [knacc][3];
791 Double_t (*vectP1)[3]=new Double_t [knacc][3];
792
793 Double_t sum[3][3];
794 Double_t dsum[3]={0,0,0};
146c29df 795 TMatrixD sumWi(3,3);
796 for(Int_t i=0;i<3;i++){
797 for(Int_t j=0;j<3;j++){
798 sum[i][j]=0;
799 sumWi(i,j)=0.;
800 }
801 }
802
2d57349e 803 for(Int_t i=0; i<knacc; i++){
f54bad66 804 AliStrLine* line1 = (AliStrLine*)lines->At(i);
dc3719f3 805 Double_t p0[3],cd[3],sigmasq[3];
146c29df 806 Double_t wmat[9];
2d57349e 807 line1->GetP0(p0);
808 line1->GetCd(cd);
dc3719f3 809 line1->GetSigma2P0(sigmasq);
146c29df 810 line1->GetWMatrix(wmat);
811 TMatrixD wWi(3,3);
812 Int_t iel=0;
813 for(Int_t ia=0;ia<3;ia++){
814 for(Int_t ib=0;ib<3;ib++){
815 wWi(ia,ib)=wmat[iel];
816 iel++;
817 }
818 }
819
820 sumWi+=wWi;
821
2d57349e 822 Double_t p1[3]={p0[0]+cd[0],p0[1]+cd[1],p0[2]+cd[2]};
823 vectP0[i][0]=p0[0];
824 vectP0[i][1]=p0[1];
825 vectP0[i][2]=p0[2];
826 vectP1[i][0]=p1[0];
827 vectP1[i][1]=p1[1];
828 vectP1[i][2]=p1[2];
829
830 Double_t matr[3][3];
831 Double_t dknow[3];
832 if(optUseWeights==0)GetStrLinDerivMatrix(p0,p1,matr,dknow);
dc3719f3 833 else GetStrLinDerivMatrix(p0,p1,sigmasq,matr,dknow);
834
2d57349e 835
836 for(Int_t iii=0;iii<3;iii++){
837 dsum[iii]+=dknow[iii];
838 for(Int_t lj=0;lj<3;lj++) sum[iii][lj]+=matr[iii][lj];
839 }
2d57349e 840 }
146c29df 841
842 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
843 Double_t covmatrix[6];
844 covmatrix[0] = invsumWi(0,0);
845 covmatrix[1] = invsumWi(0,1);
846 covmatrix[2] = invsumWi(1,1);
847 covmatrix[3] = invsumWi(0,2);
848 covmatrix[4] = invsumWi(1,2);
849 covmatrix[5] = invsumWi(2,2);
850
2d57349e 851 Double_t vett[3][3];
852 Double_t det=GetDeterminant3X3(sum);
dc3719f3 853 Double_t sigma=0;
2d57349e 854
fee9ef0d 855 if(det!=0){
856 for(Int_t zz=0;zz<3;zz++){
857 for(Int_t ww=0;ww<3;ww++){
858 for(Int_t kk=0;kk<3;kk++) vett[ww][kk]=sum[ww][kk];
859 }
860 for(Int_t kk=0;kk<3;kk++) vett[kk][zz]=dsum[kk];
861 initPos[zz]=GetDeterminant3X3(vett)/det;
862 }
863
864
865 for(Int_t i=0; i<knacc; i++){
866 Double_t p0[3]={0,0,0},p1[3]={0,0,0};
867 for(Int_t ii=0;ii<3;ii++){
868 p0[ii]=vectP0[i][ii];
869 p1[ii]=vectP1[i][ii];
870 }
871 sigma+=GetStrLinMinDist(p0,p1,initPos);
872 }
873
874 sigma=TMath::Sqrt(sigma);
875 }else{
50ff0bcd 876 sigma=999;
877 }
146c29df 878 AliESDVertex theVert(initPos,covmatrix,99999.,knacc);
879 theVert.SetDispersion(sigma);
50ff0bcd 880 delete vectP0;
881 delete vectP1;
dc3719f3 882 return theVert;
50ff0bcd 883}
884//---------------------------------------------------------------------------
6d8df534 885Bool_t AliVertexerTracks::TrackToPoint(AliExternalTrackParam *t,
0bf2e2b4 886 TMatrixD &ri,TMatrixD &wWi,
887 Bool_t uUi3by3) const
fee9ef0d 888{
889//
6d8df534 890// Extract from the AliExternalTrackParam the global coordinates ri and covariance matrix
fee9ef0d 891// wWi of the space point that it represents (to be used in VertexFitter())
892//
893
894
895 Double_t rotAngle = t->GetAlpha();
896 if(rotAngle<0.) rotAngle += 2.*TMath::Pi();
897 Double_t cosRot = TMath::Cos(rotAngle);
898 Double_t sinRot = TMath::Sin(rotAngle);
899
900 ri(0,0) = t->GetX()*cosRot-t->GetY()*sinRot;
901 ri(1,0) = t->GetX()*sinRot+t->GetY()*cosRot;
902 ri(2,0) = t->GetZ();
903
0bf2e2b4 904
905
906 if(!uUi3by3) {
907 // matrix to go from global (x,y,z) to local (y,z);
908 TMatrixD qQi(2,3);
909 qQi(0,0) = -sinRot;
910 qQi(0,1) = cosRot;
911 qQi(0,2) = 0.;
912 qQi(1,0) = 0.;
913 qQi(1,1) = 0.;
914 qQi(1,2) = 1.;
915
916 // covariance matrix of local (y,z) - inverted
0bf2e2b4 917 TMatrixD uUi(2,2);
6d8df534 918 uUi(0,0) = t->GetSigmaY2();
919 uUi(0,1) = t->GetSigmaZY();
920 uUi(1,0) = t->GetSigmaZY();
921 uUi(1,1) = t->GetSigmaZ2();
0bf2e2b4 922 //printf(" Ui :\n");
923 //printf(" %f %f\n",uUi(0,0),uUi(0,1));
924 //printf(" %f %f\n",uUi(1,0),uUi(1,1));
925
926 if(uUi.Determinant() <= 0.) return kFALSE;
927 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
928
929 // weights matrix: wWi = qQiT * uUiInv * qQi
930 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
931 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
932 wWi = m;
933 } else {
934 if(fVert.GetNContributors()<1) AliFatal("Vertex from finder is empty");
935 // matrix to go from global (x,y,z) to local (x,y,z);
936 TMatrixD qQi(3,3);
937 qQi(0,0) = cosRot;
938 qQi(0,1) = sinRot;
939 qQi(0,2) = 0.;
940 qQi(1,0) = -sinRot;
941 qQi(1,1) = cosRot;
942 qQi(1,2) = 0.;
943 qQi(2,0) = 0.;
944 qQi(2,1) = 0.;
945 qQi(2,2) = 1.;
946
947 // covariance of fVert along the track
948 Double_t p[3],pt,ptot;
949 t->GetPxPyPz(p);
950 pt = TMath::Sqrt(p[0]*p[0]+p[1]*p[1]);
951 ptot = TMath::Sqrt(pt*pt+p[2]*p[2]);
3b768a1d 952 Double_t cphi = p[0]/pt; //cos(phi)=px/pt
953 Double_t sphi = p[1]/pt; //sin(phi)=py/pt
954 Double_t clambda = pt/ptot; //cos(lambda)=pt/ptot
955 Double_t slambda = p[2]/ptot; //sin(lambda)=pz/ptot
0bf2e2b4 956 Double_t covfVert[6];
957 fVert.GetCovMatrix(covfVert);
958 Double_t covfVertalongt =
3b768a1d 959 covfVert[0]*cphi*cphi*clambda*clambda
960 +covfVert[1]*2.*cphi*sphi*clambda*clambda
961 +covfVert[3]*2.*cphi*clambda*slambda
962 +covfVert[2]*sphi*sphi*clambda*clambda
963 +covfVert[4]*2.*sphi*clambda*slambda
964 +covfVert[5]*slambda*slambda;
0bf2e2b4 965 // covariance matrix of local (x,y,z) - inverted
966 TMatrixD uUi(3,3);
3b768a1d 967 uUi(0,0) = covfVertalongt * fnSigmaForUi00 * fnSigmaForUi00;
0bf2e2b4 968 if(fDebug) printf("=====> sqrtUi00 cm %f\n",TMath::Sqrt(uUi(0,0)));
969 uUi(0,1) = 0.;
970 uUi(0,2) = 0.;
971 uUi(1,0) = 0.;
6d8df534 972 uUi(1,1) = t->GetSigmaY2();
973 uUi(1,2) = t->GetSigmaZY();
0bf2e2b4 974 uUi(2,0) = 0.;
6d8df534 975 uUi(2,1) = t->GetSigmaZY();
976 uUi(2,2) = t->GetSigmaZ2();
0bf2e2b4 977 //printf(" Ui :\n");
978 //printf(" %f %f\n",uUi(0,0),uUi(0,1));
979 //printf(" %f %f\n",uUi(1,0),uUi(1,1));
fee9ef0d 980
0bf2e2b4 981 if(uUi.Determinant() <= 0.) return kFALSE;
982 TMatrixD uUiInv(TMatrixD::kInverted,uUi);
983
984 // weights matrix: wWi = qQiT * uUiInv * qQi
985 TMatrixD uUiInvQi(uUiInv,TMatrixD::kMult,qQi);
986 TMatrixD m(qQi,TMatrixD::kTransposeMult,uUiInvQi);
987 wWi = m;
988 }
989
fee9ef0d 990
991 return kTRUE;
992}
993//---------------------------------------------------------------------------
6d8df534 994void AliVertexerTracks::TooFewTracks()
fee9ef0d 995{
50ff0bcd 996//
6d8df534 997// When the number of tracks is < fMinTracks,
998// deal with vertices not found and prepare to exit
50ff0bcd 999//
6d8df534 1000 if(fDebug) printf("TooFewTracks\n");
2d57349e 1001
50ff0bcd 1002 Double_t pos[3],err[3];
50ff0bcd 1003 pos[0] = fNominalPos[0];
1004 err[0] = TMath::Sqrt(fNominalCov[0]);
1005 pos[1] = fNominalPos[1];
1006 err[1] = TMath::Sqrt(fNominalCov[2]);
6d8df534 1007 pos[2] = fNominalPos[2];
1008 err[2] = TMath::Sqrt(fNominalCov[5]);
1009 Int_t ncontr = (err[0]>1. ? -1 : -3);
50ff0bcd 1010 fCurrentVertex = 0;
1011 fCurrentVertex = new AliESDVertex(pos,err);
1012 fCurrentVertex->SetNContributors(ncontr);
2d57349e 1013
fee9ef0d 1014 if(fConstraint) {
1015 fCurrentVertex->SetTitle("VertexerTracksWithConstraint");
1016 } else {
50ff0bcd 1017 fCurrentVertex->SetTitle("VertexerTracksNoConstraint");
fee9ef0d 1018 }
2d57349e 1019
6d8df534 1020 if(!fTrkArraySel.IsEmpty()) fTrkArraySel.Delete();
1021 if(fIdSel) {delete [] fIdSel; fIdSel=NULL;}
1022 if(fTrksToSkip) {delete [] fTrksToSkip; fTrksToSkip=NULL;}
1023
50ff0bcd 1024 return;
1025}
1026//---------------------------------------------------------------------------
fee9ef0d 1027void AliVertexerTracks::VertexFinder(Int_t optUseWeights)
1028{
2d57349e 1029
50ff0bcd 1030 // Get estimate of vertex position in (x,y) from tracks DCA
1031
1032 Double_t initPos[3];
1033 initPos[2] = 0.;
1034 for(Int_t i=0;i<2;i++)initPos[i]=fNominalPos[i];
6d8df534 1035 Int_t nacc = (Int_t)fTrkArraySel.GetEntriesFast();
50ff0bcd 1036 Double_t aver[3]={0.,0.,0.};
1037 Double_t aversq[3]={0.,0.,0.};
1038 Double_t sigmasq[3]={0.,0.,0.};
1039 Double_t sigma=0;
1040 Int_t ncombi = 0;
6d8df534 1041 AliExternalTrackParam *track1;
1042 AliExternalTrackParam *track2;
50ff0bcd 1043 Double_t pos[3],dir[3];
1044 Double_t alpha,mindist;
dc3719f3 1045 Double_t field=GetFieldkG();
2d57349e 1046
50ff0bcd 1047 for(Int_t i=0; i<nacc; i++){
6d8df534 1048 track1 = (AliExternalTrackParam*)fTrkArraySel.At(i);
50ff0bcd 1049 alpha=track1->GetAlpha();
1050 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1051 track1->GetXYZAt(mindist,field,pos);
1052 track1->GetPxPyPzAt(mindist,field,dir);
1053 AliStrLine *line1 = new AliStrLine(pos,dir);
2d57349e 1054
50ff0bcd 1055 // AliStrLine *line1 = new AliStrLine();
1056 // track1->ApproximateHelixWithLine(mindist,field,line1);
1057
1058 for(Int_t j=i+1; j<nacc; j++){
6d8df534 1059 track2 = (AliExternalTrackParam*)fTrkArraySel.At(j);
50ff0bcd 1060 alpha=track2->GetAlpha();
1061 mindist = TMath::Cos(alpha)*fNominalPos[0]+TMath::Sin(alpha)*fNominalPos[1];
1062 track2->GetXYZAt(mindist,field,pos);
1063 track2->GetPxPyPzAt(mindist,field,dir);
1064 AliStrLine *line2 = new AliStrLine(pos,dir);
1065 // AliStrLine *line2 = new AliStrLine();
1066 // track2->ApproximateHelixWithLine(mindist,field,line2);
1067 Double_t distCA=line2->GetDCA(line1);
fee9ef0d 1068 //printf("%d %d %f\n",i,j,distCA);
1069 if(fDCAcut<=0 || (fDCAcut>0&&distCA<fDCAcut)){
50ff0bcd 1070 Double_t pnt1[3],pnt2[3],crosspoint[3];
2d57349e 1071
50ff0bcd 1072 if(optUseWeights<=0){
1073 Int_t retcode = line2->Cross(line1,crosspoint);
1074 if(retcode>=0){
1075 ncombi++;
1076 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
1077 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1078 }
1079 }
1080 if(optUseWeights>0){
1081 Int_t retcode = line1->CrossPoints(line2,pnt1,pnt2);
1082 if(retcode>=0){
5c03260f 1083 Double_t cs, sn;
50ff0bcd 1084 alpha=track1->GetAlpha();
1085 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
1086 Double_t sx1=sn*sn*track1->GetSigmaY2(), sy1=cs*cs*track1->GetSigmaY2();
1087 alpha=track2->GetAlpha();
1088 cs=TMath::Cos(alpha); sn=TMath::Sin(alpha);
1089 Double_t sx2=sn*sn*track2->GetSigmaY2(), sy2=cs*cs*track2->GetSigmaY2();
1090 Double_t sz1=track1->GetSigmaZ2(), sz2=track2->GetSigmaZ2();
1091 Double_t wx1=sx2/(sx1+sx2), wx2=1.- wx1;
1092 Double_t wy1=sy2/(sy1+sy2), wy2=1.- wy1;
1093 Double_t wz1=sz2/(sz1+sz2), wz2=1.- wz1;
1094 crosspoint[0]=wx1*pnt1[0] + wx2*pnt2[0];
1095 crosspoint[1]=wy1*pnt1[1] + wy2*pnt2[1];
1096 crosspoint[2]=wz1*pnt1[2] + wz2*pnt2[2];
1097
1098 ncombi++;
1099 for(Int_t jj=0;jj<3;jj++)aver[jj]+=crosspoint[jj];
1100 for(Int_t jj=0;jj<3;jj++)aversq[jj]+=(crosspoint[jj]*crosspoint[jj]);
1101 }
1102 }
1103 }
1104 delete line2;
1105 }
1106 delete line1;
71d84967 1107 }
50ff0bcd 1108 if(ncombi>0){
1109 for(Int_t jj=0;jj<3;jj++){
1110 initPos[jj] = aver[jj]/ncombi;
fee9ef0d 1111 //printf("%f\n",initPos[jj]);
50ff0bcd 1112 aversq[jj]/=ncombi;
1113 sigmasq[jj]=aversq[jj]-initPos[jj]*initPos[jj];
1114 sigma+=sigmasq[jj];
1115 }
1116 sigma=TMath::Sqrt(TMath::Abs(sigma));
1117 }
1118 else {
1119 Warning("VertexFinder","Finder did not succed");
1120 sigma=999;
1121 }
1122 fVert.SetXYZ(initPos);
1123 fVert.SetDispersion(sigma);
1124 fVert.SetNContributors(ncombi);
2d57349e 1125}
ec1be5d5 1126//---------------------------------------------------------------------------
6d8df534 1127void AliVertexerTracks::VertexFitter()
fee9ef0d 1128{
ec1be5d5 1129//
1130// The optimal estimate of the vertex position is given by a "weighted
0bf2e2b4 1131// average of tracks positions".
fee9ef0d 1132// Original method: V. Karimaki, CMS Note 97/0051
ec1be5d5 1133//
6d8df534 1134 Bool_t useConstraint = fConstraint;
ec1be5d5 1135 Double_t initPos[3];
0bf2e2b4 1136 if(!fOnlyFitter) {
1137 fVert.GetXYZ(initPos);
1138 } else {
1139 initPos[0]=fNominalPos[0];
1140 initPos[1]=fNominalPos[1];
1141 initPos[2]=fNominalPos[2];
1142 }
1143
6d8df534 1144 Int_t nTrksSel = (Int_t)fTrkArraySel.GetEntries();
1145 if(nTrksSel==1) useConstraint=kTRUE;
ec1be5d5 1146 if(fDebug) {
0bf2e2b4 1147 printf("--- VertexFitter(): start\n");
6d8df534 1148 printf(" Number of tracks in array: %d\n",nTrksSel);
ec1be5d5 1149 printf(" Minimum # tracks required in fit: %d\n",fMinTracks);
3b768a1d 1150 printf(" Vertex position after finder: %f,%f,%f\n",initPos[0],initPos[1],initPos[2]);
fee9ef0d 1151 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 1152 }
1153
0bf2e2b4 1154 // special treatment for few-tracks fits (e.g. secondary vertices)
6d8df534 1155 Bool_t uUi3by3 = kFALSE; if(nTrksSel<5 && !useConstraint) uUi3by3 = kTRUE;
0bf2e2b4 1156
ec1be5d5 1157 Int_t i,j,k,step=0;
1158 TMatrixD rv(3,1);
1159 TMatrixD vV(3,3);
1160 rv(0,0) = initPos[0];
1161 rv(1,0) = initPos[1];
1162 rv(2,0) = 0.;
1163 Double_t xlStart,alpha;
6d8df534 1164 Int_t nTrksUsed;
fee9ef0d 1165 Double_t chi2,chi2i,chi2b;
6d8df534 1166 AliExternalTrackParam *t = 0;
ec1be5d5 1167 Int_t failed = 0;
1168
50ff0bcd 1169 // initial vertex covariance matrix
1170 TMatrixD vVb(3,3);
1171 vVb(0,0) = fNominalCov[0];
1172 vVb(0,1) = fNominalCov[1];
1173 vVb(0,2) = 0.;
1174 vVb(1,0) = fNominalCov[1];
1175 vVb(1,1) = fNominalCov[2];
1176 vVb(1,2) = 0.;
1177 vVb(2,0) = 0.;
1178 vVb(2,1) = 0.;
1179 vVb(2,2) = fNominalCov[5];
1180 TMatrixD vVbInv(TMatrixD::kInverted,vVb);
1181 TMatrixD rb(3,1);
1182 rb(0,0) = fNominalPos[0];
1183 rb(1,0) = fNominalPos[1];
1184 rb(2,0) = fNominalPos[2];
1185 TMatrixD vVbInvrb(vVbInv,TMatrixD::kMult,rb);
1186
1187
eae1677e 1188 // 2 steps:
1189 // 1st - estimate of vtx using all tracks
1190 // 2nd - estimate of global chi2
1191 for(step=0; step<2; step++) {
ec1be5d5 1192 if(fDebug) printf(" step = %d\n",step);
1193 chi2 = 0.;
6d8df534 1194 nTrksUsed = 0;
ec1be5d5 1195
0bf2e2b4 1196 if(step==1) { initPos[0]=rv(0,0); initPos[0]=rv(1,0); }
1197
ec1be5d5 1198 TMatrixD sumWiri(3,1);
1199 TMatrixD sumWi(3,3);
1200 for(i=0; i<3; i++) {
1201 sumWiri(i,0) = 0.;
1202 for(j=0; j<3; j++) sumWi(j,i) = 0.;
1203 }
1204
fee9ef0d 1205 // mean vertex constraint
1206 if(useConstraint) {
50ff0bcd 1207 for(i=0;i<3;i++) {
1208 sumWiri(i,0) += vVbInvrb(i,0);
1209 for(k=0;k<3;k++) sumWi(i,k) += vVbInv(i,k);
07680cae 1210 }
fee9ef0d 1211 // chi2
1212 TMatrixD deltar = rv; deltar -= rb;
1213 TMatrixD vVbInvdeltar(vVbInv,TMatrixD::kMult,deltar);
1214 chi2b = deltar(0,0)*vVbInvdeltar(0,0)+
1215 deltar(1,0)*vVbInvdeltar(1,0)+
1216 deltar(2,0)*vVbInvdeltar(2,0);
1217 chi2 += chi2b;
07680cae 1218 }
1219
ec1be5d5 1220 // loop on tracks
6d8df534 1221 for(k=0; k<nTrksSel; k++) {
ec1be5d5 1222 // get track from track array
6d8df534 1223 t = (AliExternalTrackParam*)fTrkArraySel.At(k);
ec1be5d5 1224 alpha = t->GetAlpha();
1225 xlStart = initPos[0]*TMath::Cos(alpha)+initPos[1]*TMath::Sin(alpha);
fee9ef0d 1226 // to vtxSeed (from finder)
6d8df534 1227 t->PropagateTo(xlStart,GetFieldkG());
fee9ef0d 1228
ec1be5d5 1229 // vector of track global coordinates
1230 TMatrixD ri(3,1);
fee9ef0d 1231 // covariance matrix of ri
1232 TMatrixD wWi(3,3);
1233
1234 // get space point from track
0bf2e2b4 1235 if(!TrackToPoint(t,ri,wWi,uUi3by3)) continue;
fee9ef0d 1236 TMatrixD wWiri(wWi,TMatrixD::kMult,ri);
ec1be5d5 1237
1238 // track chi2
1239 TMatrixD deltar = rv; deltar -= ri;
1240 TMatrixD wWideltar(wWi,TMatrixD::kMult,deltar);
1241 chi2i = deltar(0,0)*wWideltar(0,0)+
1242 deltar(1,0)*wWideltar(1,0)+
1243 deltar(2,0)*wWideltar(2,0);
1244
ec1be5d5 1245 // add to total chi2
1246 chi2 += chi2i;
1247
ec1be5d5 1248 sumWiri += wWiri;
1249 sumWi += wWi;
1250
6d8df534 1251 nTrksUsed++;
ec1be5d5 1252 } // end loop on tracks
1253
6d8df534 1254 if(nTrksUsed < fMinTracks) {
ec1be5d5 1255 failed=1;
1256 continue;
1257 }
1258
1259 Double_t determinant = sumWi.Determinant();
1260 //cerr<<" determinant: "<<determinant<<endl;
1261 if(determinant < 100.) {
1262 printf("det(V) = 0\n");
1263 failed=1;
1264 continue;
1265 }
1266
0bf2e2b4 1267 if(step==0) {
1268 // inverted of weights matrix
1269 TMatrixD invsumWi(TMatrixD::kInverted,sumWi);
1270 vV = invsumWi;
1271 // position of primary vertex
1272 rv.Mult(vV,sumWiri);
1273 }
eae1677e 1274 } // end loop on the 2 steps
ec1be5d5 1275
ec1be5d5 1276 if(failed) {
6d8df534 1277 TooFewTracks();
ec1be5d5 1278 return;
1279 }
1280
1281 Double_t position[3];
1282 position[0] = rv(0,0);
1283 position[1] = rv(1,0);
1284 position[2] = rv(2,0);
1285 Double_t covmatrix[6];
1286 covmatrix[0] = vV(0,0);
1287 covmatrix[1] = vV(0,1);
1288 covmatrix[2] = vV(1,1);
1289 covmatrix[3] = vV(0,2);
1290 covmatrix[4] = vV(1,2);
1291 covmatrix[5] = vV(2,2);
1292
dc3719f3 1293 // for correct chi2/ndf, count constraint as additional "track"
6d8df534 1294 if(fConstraint) nTrksUsed++;
ec1be5d5 1295 // store data in the vertex object
6d8df534 1296 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nTrksUsed);
ec1be5d5 1297
1298 if(fDebug) {
0bf2e2b4 1299 printf(" Vertex after fit:\n");
ec1be5d5 1300 fCurrentVertex->PrintStatus();
0bf2e2b4 1301 printf("--- VertexFitter(): finish\n");
ec1be5d5 1302 }
1303
1304 return;
1305}
50ff0bcd 1306//----------------------------------------------------------------------------
6d8df534 1307AliESDVertex* AliVertexerTracks::VertexForSelectedTracks(TObjArray *trkArray,
1308 UShort_t *id,
1309 Bool_t optUseFitter,
1310 Bool_t optPropagate)
fee9ef0d 1311{
eae1677e 1312//
6d8df534 1313// Return vertex from tracks (AliExternalTrackParam) in array
eae1677e 1314//
1315
fee9ef0d 1316 SetConstraintOff();
1317
50ff0bcd 1318 // get tracks and propagate them to initial vertex position
6d8df534 1319 fIdSel = new UShort_t[(Int_t)trkArray->GetEntriesFast()];
1320 Int_t nTrksSel = PrepareTracks(*trkArray,id,0);
1321 if(nTrksSel < TMath::Max(2,fMinTracks)) {
1322 TooFewTracks();
fee9ef0d 1323 return fCurrentVertex;
50ff0bcd 1324 }
1325
6d8df534 1326 // vertex finder
fee9ef0d 1327 switch (fAlgo) {
1328 case 1: StrLinVertexFinderMinDist(1); break;
1329 case 2: StrLinVertexFinderMinDist(0); break;
1330 case 3: HelixVertexFinder(); break;
1331 case 4: VertexFinder(1); break;
1332 case 5: VertexFinder(0); break;
1333 default: printf("Wrong algorithm\n"); break;
1334 }
fee9ef0d 1335 if(fDebug) printf(" Vertex finding completed\n");
1336
1337 // vertex fitter
6d8df534 1338 if(optUseFitter) {
1339 VertexFitter();
1340 } else {
fee9ef0d 1341 Double_t position[3]={fVert.GetXv(),fVert.GetYv(),fVert.GetZv()};
146c29df 1342 Double_t covmatrix[6];
1343 fVert.GetCovMatrix(covmatrix);
fee9ef0d 1344 Double_t chi2=99999.;
6d8df534 1345 Int_t nTrksUsed=fVert.GetNContributors();
1346 fCurrentVertex = new AliESDVertex(position,covmatrix,chi2,nTrksUsed);
fee9ef0d 1347 }
1348 fCurrentVertex->SetDispersion(fVert.GetDispersion());
1349
1350
1351 // set indices of used tracks and propagate track to found vertex
50ff0bcd 1352 UShort_t *indices = 0;
6d8df534 1353 Double_t d0z0[2],covd0z0[3];
1354 AliExternalTrackParam *t = 0;
fee9ef0d 1355 if(fCurrentVertex->GetNContributors()>0) {
1356 indices = new UShort_t[fCurrentVertex->GetNContributors()];
6d8df534 1357 for(Int_t jj=0; jj<(Int_t)fTrkArraySel.GetEntriesFast(); jj++) {
1358 indices[jj] = fIdSel[jj];
1359 t = (AliExternalTrackParam*)fTrkArraySel.At(jj);
1360 if(optPropagate && optUseFitter) {
fee9ef0d 1361 if(TMath::Sqrt(fCurrentVertex->GetXv()*fCurrentVertex->GetXv()+fCurrentVertex->GetYv()*fCurrentVertex->GetYv())<3.) {
6d8df534 1362 t->PropagateToDCA(fCurrentVertex,GetFieldkG(),100.,d0z0,covd0z0);
fee9ef0d 1363 if(fDebug) printf("Track %d propagated to found vertex\n",jj);
6d8df534 1364 } else {
fee9ef0d 1365 AliWarning("Found vertex outside beam pipe!");
1366 }
1367 }
50ff0bcd 1368 }
fee9ef0d 1369 fCurrentVertex->SetIndices(fCurrentVertex->GetNContributors(),indices);
50ff0bcd 1370 }
6d8df534 1371
1372 // clean up
1373 delete [] indices; indices=NULL;
1374 delete [] fIdSel; fIdSel=NULL;
1375 fTrkArraySel.Delete();
50ff0bcd 1376
fee9ef0d 1377 return fCurrentVertex;
eae1677e 1378}
50ff0bcd 1379//----------------------------------------------------------------------------
6d8df534 1380AliESDVertex* AliVertexerTracks::VertexForSelectedESDTracks(TObjArray *trkArray,
1381 Bool_t optUseFitter,
1382 Bool_t optPropagate)
fee9ef0d 1383{
50ff0bcd 1384//
6d8df534 1385// Return vertex from array of ESD tracks
50ff0bcd 1386//
5834e9a1 1387
6d8df534 1388 Int_t nTrks = (Int_t)trkArray->GetEntriesFast();
1389 UShort_t *id = new UShort_t[nTrks];
1390
1391 AliESDtrack *esdt = 0;
50ff0bcd 1392 for(Int_t i=0; i<nTrks; i++){
6d8df534 1393 esdt = (AliESDtrack*)trkArray->At(i);
1394 id[i] = (UShort_t)esdt->GetID();
50ff0bcd 1395 }
1396
6d8df534 1397 VertexForSelectedTracks(trkArray,id,optUseFitter,optPropagate);
1398
1399 delete [] id; id=NULL;
1400
1401 return fCurrentVertex;
50ff0bcd 1402}
1403//--------------------------------------------------------------------------