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) throw (const Char_t *) :
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) throw "AliITStrackV2: conversion failed !\n";
64 Set(par->GetX(),par->GetAlpha(),par->GetParameter(),par->GetCovariance());
66 //if (!Invariant()) throw "AliITStrackV2: conversion failed !\n";
68 SetLabel(t.GetLabel());
70 SetNumberOfClusters(t.GetITSclusters(fIndex));
72 if (t.GetStatus()&AliESDtrack::kTIME) {
74 Double_t times[10]; t.GetIntegratedTimes(times); SetIntegratedTimes(times);
75 SetIntegratedLength(t.GetIntegratedLength());
78 for(Int_t i=0; i<4; i++) fdEdxSample[i]=0;
81 //____________________________________________________________________________
82 void AliITStrackV2::ResetClusters() {
83 //------------------------------------------------------------------
84 // Reset the array of attached clusters.
85 //------------------------------------------------------------------
86 for (Int_t i=0; i<2*AliITSgeomTGeo::kNLayers; i++) fIndex[i]=-1;
88 SetNumberOfClusters(0);
91 //____________________________________________________________________________
92 void AliITStrackV2::UpdateESDtrack(ULong_t flags) const {
93 // Update track params
94 fESDtrack->UpdateTrackParams(this,flags);
95 // copy the module indices
96 for(Int_t i=0;i<12;i++) {
97 // printf(" %d\n",GetModuleIndex(i));
98 fESDtrack->SetITSModuleIndex(i,GetModuleIndex(i));
100 // copy the 4 dedx samples
101 Double_t sdedx[4]={0.,0.,0.,0.};
102 for(Int_t i=0; i<4; i++) sdedx[i]=fdEdxSample[i];
103 fESDtrack->SetITSdEdxSamples(sdedx);
106 //____________________________________________________________________________
107 AliITStrackV2::AliITStrackV2(const AliITStrackV2& t) :
109 fCheckInvariant(t.fCheckInvariant),
111 fESDtrack(t.fESDtrack)
113 //------------------------------------------------------------------
115 //------------------------------------------------------------------
117 for (i=0; i<4; i++) fdEdxSample[i]=t.fdEdxSample[i];
118 for (i=0; i<2*AliITSgeomTGeo::GetNLayers(); i++) {
119 fIndex[i]=t.fIndex[i];
120 fModule[i]=t.fModule[i];
124 //_____________________________________________________________________________
125 Int_t AliITStrackV2::Compare(const TObject *o) const {
126 //-----------------------------------------------------------------
127 // This function compares tracks according to the their curvature
128 //-----------------------------------------------------------------
129 AliITStrackV2 *t=(AliITStrackV2*)o;
130 //Double_t co=OneOverPt();
131 //Double_t c =OneOverPt();
132 Double_t co=t->GetSigmaY2()*t->GetSigmaZ2();
133 Double_t c =GetSigmaY2()*GetSigmaZ2();
135 else if (c<co) return -1;
139 //____________________________________________________________________________
141 AliITStrackV2::PropagateToVertex(const AliESDVertex *v,Double_t d,Double_t x0)
143 //------------------------------------------------------------------
144 //This function propagates a track to the minimal distance from the origin
145 //------------------------------------------------------------------
147 if (PropagateToDCA(v,bz,kVeryBig)) {
148 Double_t xOverX0,xTimesRho;
149 xOverX0 = d; xTimesRho = d*x0;
150 if (CorrectForMeanMaterial(xOverX0,xTimesRho,kTRUE)) return kTRUE;
155 //____________________________________________________________________________
156 Bool_t AliITStrackV2::
157 GetGlobalXYZat(Double_t xloc, Double_t &x, Double_t &y, Double_t &z) const {
158 //------------------------------------------------------------------
159 //This function returns a track position in the global system
160 //------------------------------------------------------------------
162 Bool_t rc=GetXYZAt(xloc, GetBz(), r);
163 x=r[0]; y=r[1]; z=r[2];
167 //_____________________________________________________________________________
168 Double_t AliITStrackV2::GetPredictedChi2(const AliCluster *c) const {
169 //-----------------------------------------------------------------
170 // This function calculates a predicted chi2 increment.
171 //-----------------------------------------------------------------
172 Double_t p[2]={c->GetY(), c->GetZ()};
173 Double_t cov[3]={c->GetSigmaY2(), 0., c->GetSigmaZ2()};
174 return AliExternalTrackParam::GetPredictedChi2(p,cov);
177 //____________________________________________________________________________
178 Bool_t AliITStrackV2::PropagateTo(Double_t xk, Double_t d, Double_t x0) {
179 //------------------------------------------------------------------
180 //This function propagates a track
181 //------------------------------------------------------------------
183 Double_t oldX=GetX(), oldY=GetY(), oldZ=GetZ();
185 //Double_t bz=GetBz();
186 //if (!AliExternalTrackParam::PropagateTo(xk,bz)) return kFALSE;
187 Double_t b[3]; GetBxByBz(b);
188 if (!AliExternalTrackParam::PropagateToBxByBz(xk,b)) return kFALSE;
189 Double_t xOverX0,xTimesRho;
190 xOverX0 = d; xTimesRho = d*x0;
191 if (!CorrectForMeanMaterial(xOverX0,xTimesRho,kTRUE)) return kFALSE;
193 Double_t x=GetX(), y=GetY(), z=GetZ();
194 if (IsStartedTimeIntegral() && x>oldX) {
195 Double_t l2 = (x-oldX)*(x-oldX) + (y-oldY)*(y-oldY) + (z-oldZ)*(z-oldZ);
196 AddTimeStep(TMath::Sqrt(l2));
202 //____________________________________________________________________________
203 Bool_t AliITStrackV2::PropagateToTGeo(Double_t xToGo, Int_t nstep, Double_t &xOverX0, Double_t &xTimesRho, Bool_t addTime) {
204 //-------------------------------------------------------------------
205 // Propagates the track to a reference plane x=xToGo in n steps.
206 // These n steps are only used to take into account the curvature.
207 // The material is calculated with TGeo. (L.Gaudichet)
208 //-------------------------------------------------------------------
210 Double_t startx = GetX(), starty = GetY(), startz = GetZ();
211 Double_t sign = (startx<xToGo) ? -1.:1.;
212 Double_t step = (xToGo-startx)/TMath::Abs(nstep);
214 Double_t start[3], end[3], mparam[7];
215 //Double_t bz = GetBz();
216 Double_t b[3]; GetBxByBz(b);
221 for (Int_t i=0; i<nstep; i++) {
223 GetXYZ(start); //starting global position
225 if (!GetXYZAt(x, bz, end)) return kFALSE;
226 //if (!AliExternalTrackParam::PropagateTo(x, bz)) return kFALSE;
227 if (!AliExternalTrackParam::PropagateToBxByBz(x, b)) return kFALSE;
228 AliTracker::MeanMaterialBudget(start, end, mparam);
229 xTimesRho = sign*mparam[4]*mparam[0];
231 if (mparam[1]<900000) {
232 if (!AliExternalTrackParam::CorrectForMeanMaterial(xOverX0,
233 xTimesRho,GetMass())) return kFALSE;
234 } else { // this happens when MeanMaterialBudget cannot cross a boundary
239 if (addTime && IsStartedTimeIntegral() && GetX()>startx) {
240 Double_t l2 = ( (GetX()-startx)*(GetX()-startx) +
241 (GetY()-starty)*(GetY()-starty) +
242 (GetZ()-startz)*(GetZ()-startz) );
243 AddTimeStep(TMath::Sqrt(l2));
249 //____________________________________________________________________________
250 Bool_t AliITStrackV2::Update(const AliCluster* c, Double_t chi2, Int_t index)
252 //------------------------------------------------------------------
253 //This function updates track parameters
254 //------------------------------------------------------------------
255 Double_t p[2]={c->GetY(), c->GetZ()};
256 Double_t cov[3]={c->GetSigmaY2(), c->GetSigmaYZ(), c->GetSigmaZ2()};
258 if (!AliExternalTrackParam::Update(p,cov)) return kFALSE;
260 Int_t n=GetNumberOfClusters();
262 if (n>fgkWARN) AliWarning("Wrong invariant !");
266 if (chi2<0) return kTRUE;
268 // fill residuals for ITS+TPC tracks
270 if (fESDtrack->GetStatus()&AliESDtrack::kTPCin) {
271 AliTracker::FillResiduals(this,p,cov,c->GetVolumeId());
276 SetNumberOfClusters(n+1);
277 SetChi2(GetChi2()+chi2);
282 Bool_t AliITStrackV2::Invariant() const {
283 //------------------------------------------------------------------
284 // This function is for debugging purpose only
285 //------------------------------------------------------------------
286 if(!fCheckInvariant) return kTRUE;
288 Int_t n=GetNumberOfClusters();
290 // take into account the misalignment error
291 Float_t maxMisalErrY2=0,maxMisalErrZ2=0;
292 for (Int_t lay=0; lay<AliITSgeomTGeo::kNLayers; lay++) {
293 maxMisalErrY2 = TMath::Max(maxMisalErrY2,AliITSReconstructor::GetRecoParam()->GetClusterMisalErrorY(lay,GetBz()));
294 maxMisalErrZ2 = TMath::Max(maxMisalErrZ2,AliITSReconstructor::GetRecoParam()->GetClusterMisalErrorZ(lay,GetBz()));
296 maxMisalErrY2 *= maxMisalErrY2;
297 maxMisalErrZ2 *= maxMisalErrZ2;
298 // this is because when we reset before refitting, we multiply the
300 maxMisalErrY2 *= 10.;
301 maxMisalErrZ2 *= 10.;
303 Double_t sP2=GetParameter()[2];
304 if (TMath::Abs(sP2) >= kAlmost1){
305 if (n>fgkWARN) Warning("Invariant","fP2=%f\n",sP2);
308 Double_t sC00=GetCovariance()[0];
309 if (sC00<=0 || sC00>(9.+maxMisalErrY2)) {
310 if (n>fgkWARN) Warning("Invariant","fC00=%f\n",sC00);
313 Double_t sC11=GetCovariance()[2];
314 if (sC11<=0 || sC11>(9.+maxMisalErrZ2)) {
315 if (n>fgkWARN) Warning("Invariant","fC11=%f\n",sC11);
318 Double_t sC22=GetCovariance()[5];
319 if (sC22<=0 || sC22>1.) {
320 if (n>fgkWARN) Warning("Invariant","fC22=%f\n",sC22);
323 Double_t sC33=GetCovariance()[9];
324 if (sC33<=0 || sC33>1.) {
325 if (n>fgkWARN) Warning("Invariant","fC33=%f\n",sC33);
328 Double_t sC44=GetCovariance()[14];
329 if (sC44<=0 /*|| sC44>6e-5*/) {
330 if (n>fgkWARN) Warning("Invariant","fC44=%f\n",sC44);
337 //____________________________________________________________________________
338 Bool_t AliITStrackV2::Propagate(Double_t alp,Double_t xk) {
339 //------------------------------------------------------------------
340 //This function propagates a track
341 //------------------------------------------------------------------
342 //Double_t bz=GetBz();
343 //if (!AliExternalTrackParam::Propagate(alp,xk,bz)) return kFALSE;
344 Double_t b[3]; GetBxByBz(b);
345 if (!AliExternalTrackParam::PropagateBxByBz(alp,xk,b)) return kFALSE;
348 Int_t n=GetNumberOfClusters();
349 if (n>fgkWARN) AliWarning("Wrong invariant !");
356 Bool_t AliITStrackV2::MeanBudgetToPrimVertex(Double_t xyz[3], Double_t step, Double_t &d) const {
358 //-------------------------------------------------------------------
359 // Get the mean material budget between the actual point and the
360 // primary vertex. (L.Gaudichet)
361 //-------------------------------------------------------------------
363 Double_t cs=TMath::Cos(GetAlpha()), sn=TMath::Sin(GetAlpha());
364 Double_t vertexX = xyz[0]*cs + xyz[1]*sn;
366 Int_t nstep = Int_t((GetX()-vertexX)/step);
367 if (nstep<1) nstep = 1;
368 step = (GetX()-vertexX)/nstep;
370 // Double_t mparam[7], densMean=0, radLength=0, length=0;
372 Double_t p1[3], p2[3], x = GetX(), bz = GetBz();
377 for (Int_t i=0; i<nstep; i++) {
379 if (!GetXYZAt(x, bz, p2)) return kFALSE;
380 AliTracker::MeanMaterialBudget(p1, p2, mparam);
381 if (mparam[1]>900000) return kFALSE;
392 Bool_t AliITStrackV2::Improve(Double_t x0,Double_t xyz[3],Double_t ers[3]) {
393 //------------------------------------------------------------------
394 //This function improves angular track parameters
395 //------------------------------------------------------------------
396 //Store the initail track parameters
399 Double_t alpha = GetAlpha();
400 Double_t par[] = {GetY(),GetZ(),GetSnp(),GetTgl(),GetSigned1Pt()};
420 Double_t cs=TMath::Cos(GetAlpha()), sn=TMath::Sin(GetAlpha());
421 //Double_t xv = xyz[0]*cs + xyz[1]*sn; // vertex
422 Double_t yv =-xyz[0]*sn + xyz[1]*cs; // in the
423 Double_t zv = xyz[2]; // local frame
425 Double_t dy = par[0] - yv, dz = par[1] - zv;
426 Double_t r2=GetX()*GetX() + dy*dy;
427 Double_t p2=(1.+ GetTgl()*GetTgl())/(GetSigned1Pt()*GetSigned1Pt());
428 Double_t beta2=p2/(p2 + GetMass()*GetMass());
429 x0*=TMath::Sqrt((1.+ GetTgl()*GetTgl())/(1.- GetSnp()*GetSnp()));
430 Double_t theta2=14.1*14.1/(beta2*p2*1e6)*x0;
431 //Double_t theta2=1.0259e-6*14*14/28/(beta2*p2)*x0*9.36*2.33;
433 Double_t cnv=GetBz()*kB2C;
435 Double_t dummy = 4/r2 - GetC()*GetC();
436 if (dummy < 0) return kFALSE;
437 Double_t parp = 0.5*(GetC()*GetX() + dy*TMath::Sqrt(dummy));
438 Double_t sigma2p = theta2*(1.-GetSnp())*(1.+GetSnp())*(1. + GetTgl()*GetTgl());
439 Double_t ovSqr2 = 1./TMath::Sqrt(r2);
440 Double_t tfact = ovSqr2*(1.-dy*ovSqr2)*(1.+dy*ovSqr2);
441 sigma2p += cov[0]*tfact*tfact;
442 sigma2p += ers[1]*ers[1]/r2;
443 sigma2p += 0.25*cov[14]*cnv*cnv*GetX()*GetX();
444 Double_t eps2p=sigma2p/(cov[5] + sigma2p);
445 par[0] += cov[3]/(cov[5] + sigma2p)*(parp - GetSnp());
446 par[2] = eps2p*GetSnp() + (1 - eps2p)*parp;
451 Double_t parl=0.5*GetC()*dz/TMath::ASin(0.5*GetC()*TMath::Sqrt(r2));
452 Double_t sigma2l=theta2;
453 sigma2l += cov[2]/r2 + cov[0]*dy*dy*dz*dz/(r2*r2*r2);
454 sigma2l += ers[2]*ers[2]/r2;
455 Double_t eps2l = sigma2l/(cov[9] + sigma2l);
456 par[1] += cov[7 ]/(cov[9] + sigma2l)*(parl - par[3]);
457 par[4] += cov[13]/(cov[9] + sigma2l)*(parl - par[3]);
458 par[3] = eps2l*par[3] + (1-eps2l)*parl;
464 Set(x,alpha,par,cov);
466 if (!Invariant()) return kFALSE;
471 void AliITStrackV2::CookdEdx(Double_t low, Double_t up) {
472 //-----------------------------------------------------------------
473 // This function calculates dE/dX within the "low" and "up" cuts.
474 // Origin: Boris Batyunya, JINR, Boris.Batiounia@cern.ch
475 // Updated: F. Prino 8-June-2009
476 //-----------------------------------------------------------------
477 // The cluster order is: SDD-1, SDD-2, SSD-1, SSD-2
481 for (Int_t il=0; il<4; il++) { // count good (>0) dE/dx values
482 if(fdEdxSample[il]>0.){
483 dedx[nc]= fdEdxSample[il];
492 Int_t swap; // sort in ascending order
495 for (Int_t i=0; i<nc-1; i++) {
496 if (dedx[i]<=dedx[i+1]) continue;
505 Double_t nl=low*nc, nu =up*nc;
507 Float_t sumweight =0;
508 for (Int_t i=0; i<nc; i++) {
510 if (i<nl+0.1) weight = TMath::Max(1.-(nl-i),0.);
511 if (i>nu-1) weight = TMath::Max(nu-i,0.);
512 sumamp+= dedx[i]*weight;
515 SetdEdx(sumamp/sumweight);
518 //____________________________________________________________________________
519 Bool_t AliITStrackV2::
520 GetPhiZat(Double_t r, Double_t &phi, Double_t &z) const {
521 //------------------------------------------------------------------
522 // This function returns the global cylindrical (phi,z) of the track
523 // position estimated at the radius r.
524 // The track curvature is neglected.
525 //------------------------------------------------------------------
526 Double_t d=GetD(0.,0.);
527 if (TMath::Abs(d) > r) {
528 if (r>1e-1) return kFALSE;
532 Double_t rcurr=TMath::Sqrt(GetX()*GetX() + GetY()*GetY());
533 if (TMath::Abs(d) > rcurr) return kFALSE;
534 Double_t globXYZcurr[3]; GetXYZ(globXYZcurr);
535 Double_t phicurr=TMath::ATan2(globXYZcurr[1],globXYZcurr[0]);
538 phi=phicurr+TMath::ASin(d/r)-TMath::ASin(d/rcurr);
540 phi=phicurr+TMath::ASin(d/r)+TMath::ASin(d/rcurr)-TMath::Pi();
543 // return a phi in [0,2pi[
544 if (phi<0.) phi+=2.*TMath::Pi();
545 else if (phi>=2.*TMath::Pi()) phi-=2.*TMath::Pi();
546 z=GetZ()+GetTgl()*(TMath::Sqrt((r-d)*(r+d))-TMath::Sqrt((rcurr-d)*(rcurr+d)));
549 //____________________________________________________________________________
550 Bool_t AliITStrackV2::
551 GetLocalXat(Double_t r,Double_t &xloc) const {
552 //------------------------------------------------------------------
553 // This function returns the local x of the track
554 // position estimated at the radius r.
555 // The track curvature is neglected.
556 //------------------------------------------------------------------
557 Double_t d=GetD(0.,0.);
558 if (TMath::Abs(d) > r) {
559 if (r>1e-1) return kFALSE;
563 Double_t rcurr=TMath::Sqrt(GetX()*GetX() + GetY()*GetY());
564 Double_t globXYZcurr[3]; GetXYZ(globXYZcurr);
565 Double_t phicurr=TMath::ATan2(globXYZcurr[1],globXYZcurr[0]);
568 phi=phicurr+TMath::ASin(d/r)-TMath::ASin(d/rcurr);
570 phi=phicurr+TMath::ASin(d/r)+TMath::ASin(d/rcurr)-TMath::Pi();
573 xloc=r*(TMath::Cos(phi)*TMath::Cos(GetAlpha())
574 +TMath::Sin(phi)*TMath::Sin(GetAlpha()));