1 /**************************************************************************
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4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
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14 **************************************************************************/
18 ///////////////////////////////////////////////////////////////////////////
19 // Implementation of the ITS track class
21 // Origin: Iouri Belikov, CERN, Jouri.Belikov@cern.ch
22 // dEdx analysis by: Boris Batyunya, JINR, Boris.Batiounia@cern.ch
23 ///////////////////////////////////////////////////////////////////////////
26 #include "AliCluster.h"
27 #include "AliESDVertex.h"
28 #include "AliITSReconstructor.h"
29 #include "AliITStrackV2.h"
30 #include "AliTracker.h"
32 const Int_t AliITStrackV2::fgkWARN = 5;
34 ClassImp(AliITStrackV2)
37 //____________________________________________________________________________
38 AliITStrackV2::AliITStrackV2() : AliKalmanTrack(),
39 fCheckInvariant(kTRUE),
43 for(Int_t i=0; i<2*AliITSgeomTGeo::kNLayers; i++) {fIndex[i]=-1; fModule[i]=-1;}
44 for(Int_t i=0; i<4; i++) fdEdxSample[i]=0;
48 //____________________________________________________________________________
49 AliITStrackV2::AliITStrackV2(AliESDtrack& t,Bool_t c):
51 fCheckInvariant(kTRUE),
52 fdEdx(t.GetITSsignal()),
55 //------------------------------------------------------------------
56 // Conversion ESD track -> ITS track.
57 // If c==kTRUE, create the ITS track out of the constrained params.
58 //------------------------------------------------------------------
59 const AliExternalTrackParam *par=&t;
61 par=t.GetConstrainedParam();
62 if (!par) AliError("AliITStrackV2: conversion failed !\n");
64 Set(par->GetX(),par->GetAlpha(),par->GetParameter(),par->GetCovariance());
66 SetLabel(t.GetLabel());
68 SetNumberOfClusters(t.GetITSclusters(fIndex));
70 if (t.GetStatus()&AliESDtrack::kTIME) {
72 Double_t times[10]; t.GetIntegratedTimes(times); SetIntegratedTimes(times);
73 SetIntegratedLength(t.GetIntegratedLength());
76 for(Int_t i=0; i<4; i++) fdEdxSample[i]=0;
79 //____________________________________________________________________________
80 void AliITStrackV2::ResetClusters() {
81 //------------------------------------------------------------------
82 // Reset the array of attached clusters.
83 //------------------------------------------------------------------
84 for (Int_t i=0; i<2*AliITSgeomTGeo::kNLayers; i++) fIndex[i]=-1;
86 SetNumberOfClusters(0);
89 //____________________________________________________________________________
90 void AliITStrackV2::UpdateESDtrack(ULong_t flags) const {
91 // Update track params
92 fESDtrack->UpdateTrackParams(this,flags);
93 // copy the module indices
94 for(Int_t i=0;i<12;i++) {
95 // printf(" %d\n",GetModuleIndex(i));
96 fESDtrack->SetITSModuleIndex(i,GetModuleIndex(i));
98 // copy the 4 dedx samples
99 Double_t sdedx[4]={0.,0.,0.,0.};
100 for(Int_t i=0; i<4; i++) sdedx[i]=fdEdxSample[i];
101 fESDtrack->SetITSdEdxSamples(sdedx);
104 //____________________________________________________________________________
105 AliITStrackV2::AliITStrackV2(const AliITStrackV2& t) :
107 fCheckInvariant(t.fCheckInvariant),
109 fESDtrack(t.fESDtrack)
111 //------------------------------------------------------------------
113 //------------------------------------------------------------------
115 for (i=0; i<4; i++) fdEdxSample[i]=t.fdEdxSample[i];
116 for (i=0; i<2*AliITSgeomTGeo::GetNLayers(); i++) {
117 fIndex[i]=t.fIndex[i];
118 fModule[i]=t.fModule[i];
122 //_____________________________________________________________________________
123 Int_t AliITStrackV2::Compare(const TObject *o) const {
124 //-----------------------------------------------------------------
125 // This function compares tracks according to the their curvature
126 //-----------------------------------------------------------------
127 AliITStrackV2 *t=(AliITStrackV2*)o;
128 //Double_t co=OneOverPt();
129 //Double_t c =OneOverPt();
130 Double_t co=t->GetSigmaY2()*t->GetSigmaZ2();
131 Double_t c =GetSigmaY2()*GetSigmaZ2();
133 else if (c<co) return -1;
137 //____________________________________________________________________________
139 AliITStrackV2::PropagateToVertex(const AliESDVertex *v,Double_t d,Double_t x0)
141 //------------------------------------------------------------------
142 //This function propagates a track to the minimal distance from the origin
143 //------------------------------------------------------------------
145 if (PropagateToDCA(v,bz,kVeryBig)) {
146 Double_t xOverX0,xTimesRho;
147 xOverX0 = d; xTimesRho = d*x0;
148 if (CorrectForMeanMaterial(xOverX0,xTimesRho,kTRUE)) return kTRUE;
153 //____________________________________________________________________________
154 Bool_t AliITStrackV2::
155 GetGlobalXYZat(Double_t xloc, Double_t &x, Double_t &y, Double_t &z) const {
156 //------------------------------------------------------------------
157 //This function returns a track position in the global system
158 //------------------------------------------------------------------
160 Bool_t rc=GetXYZAt(xloc, GetBz(), r);
161 x=r[0]; y=r[1]; z=r[2];
165 //_____________________________________________________________________________
166 Double_t AliITStrackV2::GetPredictedChi2(const AliCluster *c) const {
167 //-----------------------------------------------------------------
168 // This function calculates a predicted chi2 increment.
169 //-----------------------------------------------------------------
170 Double_t p[2]={c->GetY(), c->GetZ()};
171 Double_t cov[3]={c->GetSigmaY2(), 0., c->GetSigmaZ2()};
172 return AliExternalTrackParam::GetPredictedChi2(p,cov);
175 //____________________________________________________________________________
176 Bool_t AliITStrackV2::PropagateTo(Double_t xk, Double_t d, Double_t x0) {
177 //------------------------------------------------------------------
178 //This function propagates a track
179 //------------------------------------------------------------------
181 Double_t oldX=GetX(), oldY=GetY(), oldZ=GetZ();
183 //Double_t bz=GetBz();
184 //if (!AliExternalTrackParam::PropagateTo(xk,bz)) return kFALSE;
185 Double_t b[3]; GetBxByBz(b);
186 if (!AliExternalTrackParam::PropagateToBxByBz(xk,b)) return kFALSE;
187 Double_t xOverX0,xTimesRho;
188 xOverX0 = d; xTimesRho = d*x0;
189 if (!CorrectForMeanMaterial(xOverX0,xTimesRho,kTRUE)) return kFALSE;
191 Double_t x=GetX(), y=GetY(), z=GetZ();
192 if (IsStartedTimeIntegral() && x>oldX) {
193 Double_t l2 = (x-oldX)*(x-oldX) + (y-oldY)*(y-oldY) + (z-oldZ)*(z-oldZ);
194 AddTimeStep(TMath::Sqrt(l2));
200 //____________________________________________________________________________
201 Bool_t AliITStrackV2::PropagateToTGeo(Double_t xToGo, Int_t nstep, Double_t &xOverX0, Double_t &xTimesRho, Bool_t addTime) {
202 //-------------------------------------------------------------------
203 // Propagates the track to a reference plane x=xToGo in n steps.
204 // These n steps are only used to take into account the curvature.
205 // The material is calculated with TGeo. (L.Gaudichet)
206 //-------------------------------------------------------------------
208 Double_t startx = GetX(), starty = GetY(), startz = GetZ();
209 Double_t sign = (startx<xToGo) ? -1.:1.;
210 Double_t step = (xToGo-startx)/TMath::Abs(nstep);
212 Double_t start[3], end[3], mparam[7];
213 //Double_t bz = GetBz();
214 Double_t b[3]; GetBxByBz(b);
219 for (Int_t i=0; i<nstep; i++) {
221 GetXYZ(start); //starting global position
223 if (!GetXYZAt(x, bz, end)) return kFALSE;
224 //if (!AliExternalTrackParam::PropagateTo(x, bz)) return kFALSE;
225 if (!AliExternalTrackParam::PropagateToBxByBz(x, b)) return kFALSE;
226 AliTracker::MeanMaterialBudget(start, end, mparam);
227 xTimesRho = sign*mparam[4]*mparam[0];
229 if (mparam[1]<900000) {
230 if (!AliExternalTrackParam::CorrectForMeanMaterial(xOverX0,
231 xTimesRho,GetMass())) return kFALSE;
232 } else { // this happens when MeanMaterialBudget cannot cross a boundary
237 if (addTime && IsStartedTimeIntegral() && GetX()>startx) {
238 Double_t l2 = ( (GetX()-startx)*(GetX()-startx) +
239 (GetY()-starty)*(GetY()-starty) +
240 (GetZ()-startz)*(GetZ()-startz) );
241 AddTimeStep(TMath::Sqrt(l2));
247 //____________________________________________________________________________
248 Bool_t AliITStrackV2::Update(const AliCluster* c, Double_t chi2, Int_t index)
250 //------------------------------------------------------------------
251 //This function updates track parameters
252 //------------------------------------------------------------------
253 Double_t p[2]={c->GetY(), c->GetZ()};
254 Double_t cov[3]={c->GetSigmaY2(), c->GetSigmaYZ(), c->GetSigmaZ2()};
256 if (!AliExternalTrackParam::Update(p,cov)) return kFALSE;
258 Int_t n=GetNumberOfClusters();
260 if (n>fgkWARN) AliWarning("Wrong invariant !");
264 if (chi2<0) return kTRUE;
266 // fill residuals for ITS+TPC tracks
268 if (fESDtrack->GetStatus()&AliESDtrack::kTPCin) {
269 AliTracker::FillResiduals(this,p,cov,c->GetVolumeId());
274 SetNumberOfClusters(n+1);
275 SetChi2(GetChi2()+chi2);
280 Bool_t AliITStrackV2::Invariant() const {
281 //------------------------------------------------------------------
282 // This function is for debugging purpose only
283 //------------------------------------------------------------------
284 if(!fCheckInvariant) return kTRUE;
286 Int_t n=GetNumberOfClusters();
288 // take into account the misalignment error
289 Float_t maxMisalErrY2=0,maxMisalErrZ2=0;
290 for (Int_t lay=0; lay<AliITSgeomTGeo::kNLayers; lay++) {
291 maxMisalErrY2 = TMath::Max(maxMisalErrY2,AliITSReconstructor::GetRecoParam()->GetClusterMisalErrorY(lay,GetBz()));
292 maxMisalErrZ2 = TMath::Max(maxMisalErrZ2,AliITSReconstructor::GetRecoParam()->GetClusterMisalErrorZ(lay,GetBz()));
294 maxMisalErrY2 *= maxMisalErrY2;
295 maxMisalErrZ2 *= maxMisalErrZ2;
296 // this is because when we reset before refitting, we multiply the
298 maxMisalErrY2 *= 10.;
299 maxMisalErrZ2 *= 10.;
301 Double_t sP2=GetParameter()[2];
302 if (TMath::Abs(sP2) >= kAlmost1){
303 if (n>fgkWARN) Warning("Invariant","fP2=%f\n",sP2);
306 Double_t sC00=GetCovariance()[0];
307 if (sC00<=0 || sC00>(9.+maxMisalErrY2)) {
308 if (n>fgkWARN) Warning("Invariant","fC00=%f\n",sC00);
311 Double_t sC11=GetCovariance()[2];
312 if (sC11<=0 || sC11>(9.+maxMisalErrZ2)) {
313 if (n>fgkWARN) Warning("Invariant","fC11=%f\n",sC11);
316 Double_t sC22=GetCovariance()[5];
317 if (sC22<=0 || sC22>1.) {
318 if (n>fgkWARN) Warning("Invariant","fC22=%f\n",sC22);
321 Double_t sC33=GetCovariance()[9];
322 if (sC33<=0 || sC33>1.) {
323 if (n>fgkWARN) Warning("Invariant","fC33=%f\n",sC33);
326 Double_t sC44=GetCovariance()[14];
327 if (sC44<=0 /*|| sC44>6e-5*/) {
328 if (n>fgkWARN) Warning("Invariant","fC44=%f\n",sC44);
335 //____________________________________________________________________________
336 Bool_t AliITStrackV2::Propagate(Double_t alp,Double_t xk) {
337 //------------------------------------------------------------------
338 //This function propagates a track
339 //------------------------------------------------------------------
340 //Double_t bz=GetBz();
341 //if (!AliExternalTrackParam::Propagate(alp,xk,bz)) return kFALSE;
342 Double_t b[3]; GetBxByBz(b);
343 if (!AliExternalTrackParam::PropagateBxByBz(alp,xk,b)) return kFALSE;
346 Int_t n=GetNumberOfClusters();
347 if (n>fgkWARN) AliWarning("Wrong invariant !");
354 Bool_t AliITStrackV2::MeanBudgetToPrimVertex(Double_t xyz[3], Double_t step, Double_t &d) const {
356 //-------------------------------------------------------------------
357 // Get the mean material budget between the actual point and the
358 // primary vertex. (L.Gaudichet)
359 //-------------------------------------------------------------------
361 Double_t cs=TMath::Cos(GetAlpha()), sn=TMath::Sin(GetAlpha());
362 Double_t vertexX = xyz[0]*cs + xyz[1]*sn;
364 Int_t nstep = Int_t((GetX()-vertexX)/step);
365 if (nstep<1) nstep = 1;
366 step = (GetX()-vertexX)/nstep;
368 // Double_t mparam[7], densMean=0, radLength=0, length=0;
370 Double_t p1[3], p2[3], x = GetX(), bz = GetBz();
375 for (Int_t i=0; i<nstep; i++) {
377 if (!GetXYZAt(x, bz, p2)) return kFALSE;
378 AliTracker::MeanMaterialBudget(p1, p2, mparam);
379 if (mparam[1]>900000) return kFALSE;
390 Bool_t AliITStrackV2::Improve(Double_t x0,Double_t xyz[3],Double_t ers[3]) {
391 //------------------------------------------------------------------
392 //This function improves angular track parameters
393 //------------------------------------------------------------------
394 //Store the initail track parameters
397 Double_t alpha = GetAlpha();
398 Double_t par[] = {GetY(),GetZ(),GetSnp(),GetTgl(),GetSigned1Pt()};
418 Double_t cs=TMath::Cos(GetAlpha()), sn=TMath::Sin(GetAlpha());
419 //Double_t xv = xyz[0]*cs + xyz[1]*sn; // vertex
420 Double_t yv =-xyz[0]*sn + xyz[1]*cs; // in the
421 Double_t zv = xyz[2]; // local frame
423 Double_t dy = par[0] - yv, dz = par[1] - zv;
424 Double_t r2=GetX()*GetX() + dy*dy;
425 Double_t p2=(1.+ GetTgl()*GetTgl())/(GetSigned1Pt()*GetSigned1Pt());
426 Double_t beta2=p2/(p2 + GetMass()*GetMass());
427 x0*=TMath::Sqrt((1.+ GetTgl()*GetTgl())/(1.- GetSnp()*GetSnp()));
428 Double_t theta2=14.1*14.1/(beta2*p2*1e6)*x0;
429 //Double_t theta2=1.0259e-6*14*14/28/(beta2*p2)*x0*9.36*2.33;
431 Double_t cnv=GetBz()*kB2C;
433 Double_t dummy = 4/r2 - GetC()*GetC();
434 if (dummy < 0) return kFALSE;
435 Double_t parp = 0.5*(GetC()*GetX() + dy*TMath::Sqrt(dummy));
436 Double_t sigma2p = theta2*(1.-GetSnp())*(1.+GetSnp())*(1. + GetTgl()*GetTgl());
437 Double_t ovSqr2 = 1./TMath::Sqrt(r2);
438 Double_t tfact = ovSqr2*(1.-dy*ovSqr2)*(1.+dy*ovSqr2);
439 sigma2p += cov[0]*tfact*tfact;
440 sigma2p += ers[1]*ers[1]/r2;
441 sigma2p += 0.25*cov[14]*cnv*cnv*GetX()*GetX();
442 Double_t eps2p=sigma2p/(cov[5] + sigma2p);
443 par[0] += cov[3]/(cov[5] + sigma2p)*(parp - GetSnp());
444 par[2] = eps2p*GetSnp() + (1 - eps2p)*parp;
449 Double_t parl=0.5*GetC()*dz/TMath::ASin(0.5*GetC()*TMath::Sqrt(r2));
450 Double_t sigma2l=theta2;
451 sigma2l += cov[2]/r2 + cov[0]*dy*dy*dz*dz/(r2*r2*r2);
452 sigma2l += ers[2]*ers[2]/r2;
453 Double_t eps2l = sigma2l/(cov[9] + sigma2l);
454 par[1] += cov[7 ]/(cov[9] + sigma2l)*(parl - par[3]);
455 par[4] += cov[13]/(cov[9] + sigma2l)*(parl - par[3]);
456 par[3] = eps2l*par[3] + (1-eps2l)*parl;
462 Set(x,alpha,par,cov);
464 if (!Invariant()) return kFALSE;
469 void AliITStrackV2::CookdEdx(Double_t low, Double_t up) {
470 //-----------------------------------------------------------------
471 // This function calculates dE/dX within the "low" and "up" cuts.
472 // Origin: Boris Batyunya, JINR, Boris.Batiounia@cern.ch
473 // Updated: F. Prino 8-June-2009
474 //-----------------------------------------------------------------
475 // The cluster order is: SDD-1, SDD-2, SSD-1, SSD-2
479 for (Int_t il=0; il<4; il++) { // count good (>0) dE/dx values
480 if(fdEdxSample[il]>0.){
481 dedx[nc]= fdEdxSample[il];
490 Int_t swap; // sort in ascending order
493 for (Int_t i=0; i<nc-1; i++) {
494 if (dedx[i]<=dedx[i+1]) continue;
503 Double_t nl=low*nc, nu =up*nc;
505 Float_t sumweight =0;
506 for (Int_t i=0; i<nc; i++) {
508 if (i<nl+0.1) weight = TMath::Max(1.-(nl-i),0.);
509 if (i>nu-1) weight = TMath::Max(nu-i,0.);
510 sumamp+= dedx[i]*weight;
513 SetdEdx(sumamp/sumweight);
516 //____________________________________________________________________________
517 Bool_t AliITStrackV2::
518 GetPhiZat(Double_t r, Double_t &phi, Double_t &z) const {
519 //------------------------------------------------------------------
520 // This function returns the global cylindrical (phi,z) of the track
521 // position estimated at the radius r.
522 // The track curvature is neglected.
523 //------------------------------------------------------------------
524 Double_t d=GetD(0.,0.);
525 if (TMath::Abs(d) > r) {
526 if (r>1e-1) return kFALSE;
530 Double_t rcurr=TMath::Sqrt(GetX()*GetX() + GetY()*GetY());
531 if (TMath::Abs(d) > rcurr) return kFALSE;
532 Double_t globXYZcurr[3]; GetXYZ(globXYZcurr);
533 Double_t phicurr=TMath::ATan2(globXYZcurr[1],globXYZcurr[0]);
536 phi=phicurr+TMath::ASin(d/r)-TMath::ASin(d/rcurr);
538 phi=phicurr+TMath::ASin(d/r)+TMath::ASin(d/rcurr)-TMath::Pi();
541 // return a phi in [0,2pi[
542 if (phi<0.) phi+=2.*TMath::Pi();
543 else if (phi>=2.*TMath::Pi()) phi-=2.*TMath::Pi();
544 z=GetZ()+GetTgl()*(TMath::Sqrt((r-d)*(r+d))-TMath::Sqrt((rcurr-d)*(rcurr+d)));
547 //____________________________________________________________________________
548 Bool_t AliITStrackV2::
549 GetLocalXat(Double_t r,Double_t &xloc) const {
550 //------------------------------------------------------------------
551 // This function returns the local x of the track
552 // position estimated at the radius r.
553 // The track curvature is neglected.
554 //------------------------------------------------------------------
555 Double_t d=GetD(0.,0.);
556 if (TMath::Abs(d) > r) {
557 if (r>1e-1) return kFALSE;
561 Double_t rcurr=TMath::Sqrt(GetX()*GetX() + GetY()*GetY());
562 Double_t globXYZcurr[3]; GetXYZ(globXYZcurr);
563 Double_t phicurr=TMath::ATan2(globXYZcurr[1],globXYZcurr[0]);
566 phi=phicurr+TMath::ASin(d/r)-TMath::ASin(d/rcurr);
568 phi=phicurr+TMath::ASin(d/r)+TMath::ASin(d/rcurr)-TMath::Pi();
571 xloc=r*(TMath::Cos(phi)*TMath::Cos(GetAlpha())
572 +TMath::Sin(phi)*TMath::Sin(GetAlpha()));