1 /**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
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 **************************************************************************/
18 ///////////////////////////////////////////////////////////////////////////////
23 // Alex Bercuci <A.Bercuci@gsi.de> //
24 // Markus Fasel <M.Fasel@gsi.de> //
26 ///////////////////////////////////////////////////////////////////////////////
29 #include <TDirectory.h>
30 #include <TLinearFitter.h>
32 #include <TClonesArray.h>
33 #include <TTreeStream.h>
34 #include <TGeoMatrix.h>
35 #include <TGeoManager.h>
38 #include "AliMathBase.h"
39 #include "AliESDEvent.h"
40 #include "AliGeomManager.h"
41 #include "AliRieman.h"
42 #include "AliTrackPointArray.h"
44 #include "AliTRDgeometry.h"
45 #include "AliTRDpadPlane.h"
46 #include "AliTRDcalibDB.h"
47 #include "AliTRDReconstructor.h"
48 #include "AliTRDCalibraFillHisto.h"
49 #include "AliTRDrecoParam.h"
51 #include "AliTRDcluster.h"
52 #include "AliTRDdigitsParam.h"
53 #include "AliTRDseedV1.h"
54 #include "AliTRDtrackV1.h"
55 #include "AliTRDtrackerV1.h"
56 #include "AliTRDtrackerDebug.h"
57 #include "AliTRDtrackingChamber.h"
58 #include "AliTRDchamberTimeBin.h"
60 ClassImp(AliTRDtrackerV1)
61 ClassImp(AliTRDtrackerV1::AliTRDLeastSquare)
62 ClassImp(AliTRDtrackerV1::AliTRDtrackFitterRieman)
64 const Float_t AliTRDtrackerV1::fgkMinClustersInTrack = 0.5; //
65 const Float_t AliTRDtrackerV1::fgkLabelFraction = 0.8; //
66 const Double_t AliTRDtrackerV1::fgkMaxChi2 = 12.0; //
67 const Double_t AliTRDtrackerV1::fgkMaxSnp = 0.95; // Maximum local sine of the azimuthal angle
68 const Double_t AliTRDtrackerV1::fgkMaxStep = 2.0; // Maximal step size in propagation
69 Double_t AliTRDtrackerV1::fgTopologicQA[kNConfigs] = {
70 0.5112, 0.5112, 0.5112, 0.0786, 0.0786,
71 0.0786, 0.0786, 0.0579, 0.0579, 0.0474,
72 0.0474, 0.0408, 0.0335, 0.0335, 0.0335
74 const Double_t AliTRDtrackerV1::fgkX0[kNPlanes] = {
75 300.2, 312.8, 325.4, 338.0, 350.6, 363.2};
76 Int_t AliTRDtrackerV1::fgNTimeBins = 0;
77 AliRieman* AliTRDtrackerV1::fgRieman = NULL;
78 TLinearFitter* AliTRDtrackerV1::fgTiltedRieman = NULL;
79 TLinearFitter* AliTRDtrackerV1::fgTiltedRiemanConstrained = NULL;
81 //____________________________________________________________________
82 AliTRDtrackerV1::AliTRDtrackerV1(AliTRDReconstructor *rec)
84 ,fkReconstructor(NULL)
94 // Default constructor.
97 SetReconstructor(rec); // initialize reconstructor
99 // initialize geometry
100 if(!AliGeomManager::GetGeometry()){
101 AliFatal("Could not get geometry.");
103 fGeom = new AliTRDgeometry();
104 fGeom->CreateClusterMatrixArray();
105 TGeoHMatrix *matrix = NULL;
106 Double_t loc[] = {0., 0., 0.};
107 Double_t glb[] = {0., 0., 0.};
108 for(Int_t ily=kNPlanes; ily--;){
110 while(!(matrix = fGeom->GetClusterMatrix(AliTRDgeometry::GetDetector(ily, 2, ism)))) ism++;
112 AliError(Form("Could not get transformation matrix for layer %d. Use default.", ily));
113 fR[ily] = fgkX0[ily];
116 matrix->LocalToMaster(loc, glb);
117 fR[ily] = glb[0]+ AliTRDgeometry::AnodePos()-.5*AliTRDgeometry::AmThick() - AliTRDgeometry::DrThick();
120 // initialize cluster containers
121 for (Int_t isector = 0; isector < AliTRDgeometry::kNsector; isector++) new(&fTrSec[isector]) AliTRDtrackingSector(fGeom, isector);
124 memset(fTrackQuality, 0, kMaxTracksStack*sizeof(Double_t));
125 memset(fSeedLayer, 0, kMaxTracksStack*sizeof(Int_t));
126 memset(fSeedTB, 0, kNSeedPlanes*sizeof(AliTRDchamberTimeBin*));
127 fTracksESD = new TClonesArray("AliESDtrack", 2*kMaxTracksStack);
128 fTracksESD->SetOwner();
131 //____________________________________________________________________
132 AliTRDtrackerV1::~AliTRDtrackerV1()
138 if(fgRieman) delete fgRieman; fgRieman = NULL;
139 if(fgTiltedRieman) delete fgTiltedRieman; fgTiltedRieman = NULL;
140 if(fgTiltedRiemanConstrained) delete fgTiltedRiemanConstrained; fgTiltedRiemanConstrained = NULL;
141 for(Int_t isl =0; isl<kNSeedPlanes; isl++) if(fSeedTB[isl]) delete fSeedTB[isl];
142 if(fTracksESD){ fTracksESD->Delete(); delete fTracksESD; }
143 if(fTracks) {fTracks->Delete(); delete fTracks;}
144 if(fTracklets) {fTracklets->Delete(); delete fTracklets;}
146 fClusters->Delete(); delete fClusters;
148 if(fGeom) delete fGeom;
151 //____________________________________________________________________
152 Int_t AliTRDtrackerV1::Clusters2Tracks(AliESDEvent *esd)
155 // Steering stand alone tracking for full TRD detector
158 // esd : The ESD event. On output it contains
159 // the ESD tracks found in TRD.
162 // Number of tracks found in the TRD detector.
164 // Detailed description
165 // 1. Launch individual SM trackers.
166 // See AliTRDtrackerV1::Clusters2TracksSM() for details.
170 AliError("Reconstruction configuration not initialized. Call first AliTRDReconstructor::SetRecoParam().");
174 //AliInfo("Start Track Finder ...");
176 for(int ism=0; ism<AliTRDgeometry::kNsector; ism++){
177 // for(int ism=1; ism<2; ism++){
178 //AliInfo(Form("Processing supermodule %i ...", ism));
179 ntracks += Clusters2TracksSM(ism, esd);
181 AliInfo(Form("Number of tracks: !TRDin[%d]", ntracks));
186 //_____________________________________________________________________________
187 Bool_t AliTRDtrackerV1::GetTrackPoint(Int_t index, AliTrackPoint &p) const
189 //AliInfo(Form("Asking for tracklet %d", index));
191 // reset position of the point before using it
192 p.SetXYZ(0., 0., 0.);
193 AliTRDseedV1 *tracklet = GetTracklet(index);
194 if (!tracklet) return kFALSE;
196 // get detector for this tracklet
197 Int_t det = tracklet->GetDetector();
198 Int_t sec = fGeom->GetSector(det);
199 Double_t alpha = (sec+.5)*AliTRDgeometry::GetAlpha(),
200 sinA = TMath::Sin(alpha),
201 cosA = TMath::Cos(alpha);
203 local[0] = tracklet->GetX();
204 local[1] = tracklet->GetY();
205 local[2] = tracklet->GetZ();
207 fGeom->RotateBack(det, local, global);
209 Double_t cov2D[3]; Float_t cov[6];
210 tracklet->GetCovAt(local[0], cov2D);
211 cov[0] = cov2D[0]*sinA*sinA;
212 cov[1] =-cov2D[0]*sinA*cosA;
213 cov[2] =-cov2D[1]*sinA;
214 cov[3] = cov2D[0]*cosA*cosA;
215 cov[4] = cov2D[1]*cosA;
217 // store the global position of the tracklet and its covariance matrix in the track point
218 p.SetXYZ(global[0],global[1],global[2], cov);
221 AliGeomManager::ELayerID iLayer = AliGeomManager::ELayerID(AliGeomManager::kTRD1+fGeom->GetLayer(det));
222 Int_t modId = fGeom->GetSector(det) * AliTRDgeometry::kNstack + fGeom->GetStack(det);
223 UShort_t volid = AliGeomManager::LayerToVolUID(iLayer, modId);
224 p.SetVolumeID(volid);
229 //____________________________________________________________________
230 TLinearFitter* AliTRDtrackerV1::GetTiltedRiemanFitter()
232 if(!fgTiltedRieman) fgTiltedRieman = new TLinearFitter(4, "hyp4");
233 return fgTiltedRieman;
236 //____________________________________________________________________
237 TLinearFitter* AliTRDtrackerV1::GetTiltedRiemanFitterConstraint()
239 if(!fgTiltedRiemanConstrained) fgTiltedRiemanConstrained = new TLinearFitter(2, "hyp2");
240 return fgTiltedRiemanConstrained;
243 //____________________________________________________________________
244 AliRieman* AliTRDtrackerV1::GetRiemanFitter()
246 if(!fgRieman) fgRieman = new AliRieman(AliTRDseedV1::kNtb * AliTRDgeometry::kNlayer);
250 //_____________________________________________________________________________
251 Int_t AliTRDtrackerV1::PropagateBack(AliESDEvent *event)
253 // Propagation of ESD tracks from TPC to TOF detectors and building of the TRD track. For building
254 // a TRD track an ESD track is used as seed. The informations obtained on the TRD track (measured points,
255 // covariance, PID, etc.) are than used to update the corresponding ESD track.
256 // Each track seed is first propagated to the geometrical limit of the TRD detector.
257 // Its prolongation is searched in the TRD and if corresponding clusters are found tracklets are
258 // constructed out of them (see AliTRDseedV1::AttachClusters()) and the track is updated.
259 // Otherwise the ESD track is left unchanged.
261 // The following steps are performed:
262 // 1. Selection of tracks based on the variance in the y-z plane.
263 // 2. Propagation to the geometrical limit of the TRD volume. If track propagation fails the AliESDtrack::kTRDStop is set.
264 // 3. Prolongation inside the fiducial volume (see AliTRDtrackerV1::FollowBackProlongation()) and marking
265 // the following status bits:
266 // - AliESDtrack::kTRDin - if the tracks enters the TRD fiducial volume
267 // - AliESDtrack::kTRDStop - if the tracks fails propagation
268 // - AliESDtrack::kTRDbackup - if the tracks fulfills chi2 conditions and qualify for refitting
269 // 4. Writting to friends, PID, MC label, quality etc. Setting status bit AliESDtrack::kTRDout.
270 // 5. Propagation to TOF. If track propagation fails the AliESDtrack::kTRDStop is set.
273 if(!fClusters || !fClusters->GetEntriesFast()){
274 AliInfo("No TRD clusters");
277 AliTRDCalibraFillHisto *calibra = AliTRDCalibraFillHisto::Instance(); // Calibration monitor
278 if (!calibra) AliInfo("Could not get Calibra instance");
279 if (!fgNTimeBins) fgNTimeBins = fkReconstructor->GetNTimeBins();
282 Int_t nFound = 0, // number of tracks found
283 nBacked = 0, // number of tracks backed up for refit
284 nSeeds = 0, // total number of ESD seeds
285 nTRDseeds= 0, // number of seeds in the TRD acceptance
286 nTPCseeds= 0; // number of TPC seeds
287 Float_t foundMin = 20.0;
289 Float_t *quality = NULL;
291 nSeeds = event->GetNumberOfTracks();
292 // Sort tracks according to quality
293 // (covariance in the yz plane)
295 quality = new Float_t[nSeeds];
296 index = new Int_t[nSeeds];
297 for (Int_t iSeed = nSeeds; iSeed--;) {
298 AliESDtrack *seed = event->GetTrack(iSeed);
299 Double_t covariance[15];
300 seed->GetExternalCovariance(covariance);
301 quality[iSeed] = covariance[0] + covariance[2];
303 TMath::Sort(nSeeds, quality, index,kFALSE);
306 // Propagate all seeds
309 for (Int_t iSeed = 0; iSeed < nSeeds; iSeed++) {
311 // Get the seeds in sorted sequence
312 AliESDtrack *seed = event->GetTrack(index[iSeed]);
313 Float_t p4 = seed->GetC(seed->GetBz());
315 // Check the seed status
316 ULong_t status = seed->GetStatus();
317 if ((status & AliESDtrack::kTPCout) == 0) continue;
318 if ((status & AliESDtrack::kTRDout) != 0) continue;
320 // Propagate to the entrance in the TRD mother volume
321 new(&track) AliTRDtrackV1(*seed);
322 if(AliTRDgeometry::GetXtrdBeg() > (fgkMaxStep + track.GetX()) && !PropagateToX(track, AliTRDgeometry::GetXtrdBeg(), fgkMaxStep)){
323 seed->UpdateTrackParams(&track, AliESDtrack::kTRDStop);
326 if(!AdjustSector(&track)){
327 seed->UpdateTrackParams(&track, AliESDtrack::kTRDStop);
330 if(TMath::Abs(track.GetSnp()) > fgkMaxSnp) {
331 seed->UpdateTrackParams(&track, AliESDtrack::kTRDStop);
337 // store track status at TRD entrance
338 seed->UpdateTrackParams(&track, AliESDtrack::kTRDbackup);
340 // prepare track and do propagation in the TRD
341 track.SetReconstructor(fkReconstructor);
342 track.SetKink(Bool_t(seed->GetKinkIndex(0)));
343 expectedClr = FollowBackProlongation(track);
344 // check if track entered the TRD fiducial volume
345 if(track.GetTrackIn()){
346 seed->UpdateTrackParams(&track, AliESDtrack::kTRDin);
349 // check if track was stopped in the TRD
351 seed->UpdateTrackParams(&track, AliESDtrack::kTRDStop);
357 // computes PID for track
359 // update calibration references using this track
360 if(calibra->GetHisto2d()) calibra->UpdateHistogramsV1(&track);
361 // save calibration object
362 if (fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) > 0) {
363 AliTRDtrackV1 *calibTrack = new AliTRDtrackV1(track);
364 calibTrack->SetOwner();
365 seed->AddCalibObject(calibTrack);
368 seed->UpdateTrackParams(&track, AliESDtrack::kTRDout);
369 track.UpdateESDtrack(seed);
372 if ((TMath::Abs(track.GetC(track.GetBz()) - p4) / TMath::Abs(p4) < 0.2) ||(track.Pt() > 0.8)) {
374 // Make backup for back propagation
375 Int_t foundClr = track.GetNumberOfClusters();
376 if (foundClr >= foundMin) {
377 track.CookLabel(1. - fgkLabelFraction);
378 //if(track.GetBackupTrack()) UseClusters(track.GetBackupTrack());
380 // Sign only gold tracks
381 if (track.GetChi2() / track.GetNumberOfClusters() < 4) {
382 //if ((seed->GetKinkIndex(0) == 0) && (track.Pt() < 1.5)) UseClusters(&track);
384 Bool_t isGold = kFALSE;
387 if (track.GetChi2() / track.GetNumberOfClusters() < 5) {
388 if (track.GetBackupTrack()) seed->UpdateTrackParams(track.GetBackupTrack(),AliESDtrack::kTRDbackup);
394 if ((!isGold) && (track.GetNCross() == 0) && (track.GetChi2() / track.GetNumberOfClusters() < 7)) {
395 //seed->UpdateTrackParams(track, AliESDtrack::kTRDbackup);
396 if (track.GetBackupTrack()) seed->UpdateTrackParams(track.GetBackupTrack(),AliESDtrack::kTRDbackup);
401 if ((!isGold) && (track.GetBackupTrack())) {
402 if ((track.GetBackupTrack()->GetNumberOfClusters() > foundMin) && ((track.GetBackupTrack()->GetChi2()/(track.GetBackupTrack()->GetNumberOfClusters()+1)) < 7)) {
403 seed->UpdateTrackParams(track.GetBackupTrack(),AliESDtrack::kTRDbackup);
411 // Propagation to the TOF
412 if(!(seed->GetStatus()&AliESDtrack::kTRDStop)) {
413 Int_t sm = track.GetSector();
414 // default value in case we have problems with the geometry.
415 Double_t xtof = 371.;
416 //Calculate radial position of the beginning of the TOF
417 //mother volume. In order to avoid mixing of the TRD
418 //and TOF modules some hard values are needed. This are:
419 //1. The path to the TOF module.
420 //2. The width of the TOF (29.05 cm)
421 //(with the help of Annalisa de Caro Mar-17-2009)
423 gGeoManager->cd(Form("/ALIC_1/B077_1/BSEGMO%d_1/BTOF%d_1", sm, sm));
424 TGeoHMatrix *m = NULL;
425 Double_t loc[]={0., 0., -.5*29.05}, glob[3];
427 if((m=gGeoManager->GetCurrentMatrix())){
428 m->LocalToMaster(loc, glob);
429 xtof = TMath::Sqrt(glob[0]*glob[0]+glob[1]*glob[1]);
432 if(xtof > (fgkMaxStep + track.GetX()) && !PropagateToX(track, xtof, fgkMaxStep)){
433 seed->UpdateTrackParams(&track, AliESDtrack::kTRDStop);
436 if(!AdjustSector(&track)){
437 seed->UpdateTrackParams(&track, AliESDtrack::kTRDStop);
440 if(TMath::Abs(track.GetSnp()) > fgkMaxSnp){
441 seed->UpdateTrackParams(&track, AliESDtrack::kTRDStop);
444 //seed->UpdateTrackParams(&track, AliESDtrack::kTRDout);
445 // TODO obsolete - delete
446 seed->SetTRDQuality(track.StatusForTOF());
448 seed->SetTRDBudget(track.GetBudget(0));
450 if(index) delete [] index;
451 if(quality) delete [] quality;
453 AliInfo(Form("Number of seeds: TPCout[%d] TRDin[%d]", nTPCseeds, nTRDseeds));
454 AliInfo(Form("Number of tracks: TRDout[%d] TRDbackup[%d]", nFound, nBacked));
456 // run stand alone tracking
457 if (fkReconstructor->IsSeeding()) Clusters2Tracks(event);
463 //____________________________________________________________________
464 Int_t AliTRDtrackerV1::RefitInward(AliESDEvent *event)
467 // Refits tracks within the TRD. The ESD event is expected to contain seeds
468 // at the outer part of the TRD.
469 // The tracks are propagated to the innermost time bin
470 // of the TRD and the ESD event is updated
471 // Origin: Thomas KUHR (Thomas.Kuhr@cern.ch)
474 Int_t nseed = 0; // contor for loaded seeds
475 Int_t found = 0; // contor for updated TRD tracks
478 if(!fClusters || !fClusters->GetEntriesFast()){
479 AliInfo("No TRD clusters");
483 for (Int_t itrack = 0; itrack < event->GetNumberOfTracks(); itrack++) {
484 AliESDtrack *seed = event->GetTrack(itrack);
485 ULong_t status = seed->GetStatus();
487 new(&track) AliTRDtrackV1(*seed);
488 if (track.GetX() < 270.0) {
489 seed->UpdateTrackParams(&track, AliESDtrack::kTRDbackup);
493 // reject tracks which failed propagation in the TRD or
494 // are produced by the TRD stand alone tracker
495 if(!(status & AliESDtrack::kTRDout)) continue;
496 if(!(status & AliESDtrack::kTRDin)) continue;
499 track.ResetCovariance(50.0);
501 // do the propagation and processing
502 Bool_t kUPDATE = kFALSE;
503 Double_t xTPC = 250.0;
504 if(FollowProlongation(track)){
505 // Update the friend track
506 if (fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) > 0){
507 TObject *o = NULL; Int_t ic = 0;
508 AliTRDtrackV1 *calibTrack = NULL;
509 while((o = seed->GetCalibObject(ic++))){
510 if(!(calibTrack = dynamic_cast<AliTRDtrackV1*>(o))) continue;
511 calibTrack->SetTrackOut(&track);
516 if (PropagateToX(track, xTPC, fgkMaxStep)) { // -with update
517 seed->UpdateTrackParams(&track, AliESDtrack::kTRDrefit);
523 // Prolongate to TPC without update
525 AliTRDtrackV1 tt(*seed);
526 if (PropagateToX(tt, xTPC, fgkMaxStep)) seed->UpdateTrackParams(&tt, AliESDtrack::kTRDbackup);
529 AliInfo(Form("Number of seeds: TRDout[%d]", nseed));
530 AliInfo(Form("Number of tracks: TRDrefit[%d]", found));
535 //____________________________________________________________________
536 Int_t AliTRDtrackerV1::FollowProlongation(AliTRDtrackV1 &t)
538 // Extrapolates the TRD track in the TPC direction.
541 // t : the TRD track which has to be extrapolated
544 // number of clusters attached to the track
546 // Detailed description
548 // Starting from current radial position of track <t> this function
549 // extrapolates the track through the 6 TRD layers. The following steps
550 // are being performed for each plane:
552 // a. get plane limits in the local x direction
553 // b. check crossing sectors
554 // c. check track inclination
555 // 2. search tracklet in the tracker list (see GetTracklet() for details)
556 // 3. evaluate material budget using the geo manager
557 // 4. propagate and update track using the tracklet information.
562 Int_t nClustersExpected = 0;
563 for (Int_t iplane = kNPlanes; iplane--;) {
565 AliTRDseedV1 *tracklet = GetTracklet(&t, iplane, index);
566 AliDebug(2, Form("Tracklet[%p] ly[%d] idx[%d]", (void*)tracklet, iplane, index));
567 if(!tracklet) continue;
568 if(!tracklet->IsOK()){
569 AliDebug(1, Form("Tracklet Det[%d] !OK", tracklet->GetDetector()));
572 Double_t x = tracklet->GetX();//GetX0();
573 // reject tracklets which are not considered for inward refit
574 if(x > t.GetX()+fgkMaxStep) continue;
576 // append tracklet to track
577 t.SetTracklet(tracklet, index);
579 if (x < (t.GetX()-fgkMaxStep) && !PropagateToX(t, x+fgkMaxStep, fgkMaxStep)) break;
580 if (!AdjustSector(&t)) break;
582 // Start global position
586 // End global position
587 Double_t alpha = t.GetAlpha(), y, z;
588 if (!t.GetProlongation(x,y,z)) break;
590 xyz1[0] = x * TMath::Cos(alpha) - y * TMath::Sin(alpha);
591 xyz1[1] = x * TMath::Sin(alpha) + y * TMath::Cos(alpha);
594 Double_t length = TMath::Sqrt(
595 (xyz0[0]-xyz1[0])*(xyz0[0]-xyz1[0]) +
596 (xyz0[1]-xyz1[1])*(xyz0[1]-xyz1[1]) +
597 (xyz0[2]-xyz1[2])*(xyz0[2]-xyz1[2])
600 // Get material budget
602 if(AliTracker::MeanMaterialBudget(xyz0, xyz1, param)<=0.) break;
603 Double_t xrho= param[0]*param[4];
604 Double_t xx0 = param[1]; // Get mean propagation parameters
606 // Propagate and update
607 t.PropagateTo(x, xx0, xrho);
608 if (!AdjustSector(&t)) break;
611 Double_t cov[3]; tracklet->GetCovAt(x, cov);
612 Double_t p[2] = { tracklet->GetY(), tracklet->GetZ()};
613 Double_t chi2 = ((AliExternalTrackParam)t).GetPredictedChi2(p, cov);
614 if (chi2 < 1e+10 && t.Update(p, cov, chi2)){
615 nClustersExpected += tracklet->GetN();
619 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) > 1){
621 for(int iplane=0; iplane<AliTRDgeometry::kNlayer; iplane++){
622 AliTRDseedV1 *tracklet = GetTracklet(&t, iplane, index);
623 if(!tracklet) continue;
624 t.SetTracklet(tracklet, index);
627 if(fkReconstructor->IsDebugStreaming()){
628 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
629 TTreeSRedirector &cstreamer = *fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker);
630 AliTRDtrackV1 track(t);
632 cstreamer << "FollowProlongation"
633 << "EventNumber=" << eventNumber
634 << "ncl=" << nClustersExpected
635 << "track.=" << &track
639 return nClustersExpected;
643 //_____________________________________________________________________________
644 Int_t AliTRDtrackerV1::FollowBackProlongation(AliTRDtrackV1 &t)
646 // Extrapolates/Build the TRD track in the TOF direction.
649 // t : the TRD track which has to be extrapolated
652 // number of clusters attached to the track
654 // Starting from current radial position of track <t> this function
655 // extrapolates the track through the 6 TRD layers. The following steps
656 // are being performed for each plane:
657 // 1. Propagate track to the entrance of the next chamber:
658 // - get chamber limits in the radial direction
659 // - check crossing sectors
660 // - check track inclination
661 // - check track prolongation against boundary conditions (see exclusion boundaries on AliTRDgeometry::IsOnBoundary())
662 // 2. Build tracklet (see AliTRDseed::AttachClusters() for details) for this layer if needed. If only
663 // Kalman filter is needed and tracklets are already linked to the track this step is skipped.
664 // 3. Fit tracklet using the information from the Kalman filter.
665 // 4. Propagate and update track at reference radial position of the tracklet.
666 // 5. Register tracklet with the tracker and track; update pulls monitoring.
669 // 1. During the propagation a bit map is filled detailing the status of the track in each TRD chamber. The following errors are being registered for each tracklet:
670 // - AliTRDtrackV1::kProlongation : track prolongation failed
671 // - AliTRDtrackV1::kPropagation : track prolongation failed
672 // - AliTRDtrackV1::kAdjustSector : failed during sector crossing
673 // - AliTRDtrackV1::kSnp : too large bending
674 // - AliTRDtrackV1::kTrackletInit : fail to initialize tracklet
675 // - AliTRDtrackV1::kUpdate : fail to attach clusters or fit the tracklet
676 // - AliTRDtrackV1::kUnknown : anything which is not covered before
677 // 2. By default the status of the track before first TRD update is saved.
682 // Alexandru Bercuci <A.Bercuci@gsi.de>
686 Double_t driftLength = .5*AliTRDgeometry::AmThick() + AliTRDgeometry::DrThick();
687 AliTRDtrackingChamber *chamber = NULL;
689 Int_t debugLevel = fkReconstructor->IsDebugStreaming() ? fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) : 0;
690 TTreeSRedirector *cstreamer = fkReconstructor->IsDebugStreaming() ? fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker) : 0x0;
692 Bool_t kStoreIn(kTRUE), //
693 kPropagateIn(kTRUE), //
694 kStandAlone(kFALSE), // toggle tracker awarness of stand alone seeding
695 kUseTRD(fkRecoParam->IsOverPtThreshold(t.Pt()));// use TRD measurment to update Kalman
698 AliTRDseedV1 tracklet, *ptrTracklet = NULL;
699 // Special case for stand alone tracking
700 // - store all tracklets found by seeding
701 // - start propagation from first tracklet found
702 AliTRDseedV1 *tracklets[kNPlanes];
703 memset(tracklets, 0, sizeof(AliTRDseedV1 *) * kNPlanes);
704 for(Int_t ip(kNPlanes); ip--;){
705 if(!(tracklets[ip] = t.GetTracklet(ip))) continue;
707 if(tracklets[ip]->IsOK()) startLayer=ip;
710 AliDebug(4, Form("SA[%c] Start[%d]\n"
711 " [0]idx[%d] traklet[%p]\n"
712 " [1]idx[%d] traklet[%p]\n"
713 " [2]idx[%d] traklet[%p]\n"
714 " [3]idx[%d] traklet[%p]\n"
715 " [4]idx[%d] traklet[%p]\n"
716 " [5]idx[%d] traklet[%p]"
717 , kStandAlone?'y':'n', startLayer
718 , t.GetTrackletIndex(0), (void*)tracklets[0]
719 , t.GetTrackletIndex(1), (void*)tracklets[1]
720 , t.GetTrackletIndex(2), (void*)tracklets[2]
721 , t.GetTrackletIndex(3), (void*)tracklets[3]
722 , t.GetTrackletIndex(4), (void*)tracklets[4]
723 , t.GetTrackletIndex(5), (void*)tracklets[5]));
725 // Loop through the TRD layers
726 TGeoHMatrix *matrix = NULL;
728 for (Int_t ily=startLayer, sm=-1, stk=-1, det=-1; ily < AliTRDgeometry::kNlayer; ily++) {
729 AliDebug(2, Form("Propagate to x[%d] = %7.2f", ily, fR[ily]));
731 // rough estimate of the entry point
732 if (!t.GetProlongation(fR[ily], y, z)){
734 t.SetStatus(AliTRDtrackV1::kProlongation);
735 AliDebug(4, Form("Failed Rough Prolongation to ly[%d] x[%7.2f] y[%7.2f] z[%7.2f]", ily, fR[ily], y, z));
739 // find sector / stack / detector
741 // TODO cross check with y value !
742 stk = fGeom->GetStack(z, ily);
743 det = stk>=0 ? AliTRDgeometry::GetDetector(ily, stk, sm) : -1;
744 matrix = det>=0 ? fGeom->GetClusterMatrix(det) : NULL;
745 AliDebug(3, Form("Propagate to det[%3d]", det));
747 // check if supermodule/chamber is installed
748 if( !fGeom->GetSMstatus(sm) ||
750 fGeom->IsHole(ily, stk, sm) ||
752 AliDebug(4, Form("Missing Geometry ly[%d]. Guess radial position", ily));
753 // propagate to the default radial position
754 if(fR[ily] > (fgkMaxStep + t.GetX()) && !PropagateToX(t, fR[ily], fgkMaxStep)){
756 t.SetStatus(AliTRDtrackV1::kPropagation);
757 AliDebug(4, "Failed Propagation [Missing Geometry]");
760 if(!AdjustSector(&t)){
762 t.SetStatus(AliTRDtrackV1::kAdjustSector);
763 AliDebug(4, "Failed Adjust Sector [Missing Geometry]");
766 if(TMath::Abs(t.GetSnp()) > fgkMaxSnp){
768 t.SetStatus(AliTRDtrackV1::kSnp);
769 AliDebug(4, "Failed Max Snp [Missing Geometry]");
772 t.SetStatus(AliTRDtrackV1::kGeometry, ily);
776 // retrieve rotation matrix for the current chamber
777 Double_t loc[] = {AliTRDgeometry::AnodePos()- driftLength, 0., 0.};
778 Double_t glb[] = {0., 0., 0.};
779 matrix->LocalToMaster(loc, glb);
781 // Propagate to the radial distance of the current layer
782 x = glb[0] - fgkMaxStep;
783 if(x > (fgkMaxStep + t.GetX()) && !PropagateToX(t, x, fgkMaxStep)){
785 t.SetStatus(AliTRDtrackV1::kPropagation);
786 AliDebug(4, Form("Failed Initial Propagation to x[%7.2f]", x));
789 if(!AdjustSector(&t)){
791 t.SetStatus(AliTRDtrackV1::kAdjustSector);
792 AliDebug(4, "Failed Adjust Sector Start");
795 if(TMath::Abs(t.GetSnp()) > fgkMaxSnp) {
797 t.SetStatus(AliTRDtrackV1::kSnp);
798 AliDebug(4, Form("Failed Max Snp[%f] MaxSnp[%f]", t.GetSnp(), fgkMaxSnp));
801 Bool_t doRecalculate = kFALSE;
802 if(sm != t.GetSector()){
804 doRecalculate = kTRUE;
806 if(stk != fGeom->GetStack(z, ily)){
807 stk = fGeom->GetStack(z, ily);
808 doRecalculate = kTRUE;
811 det = AliTRDgeometry::GetDetector(ily, stk, sm);
812 if(!(matrix = fGeom->GetClusterMatrix(det))){
813 t.SetStatus(AliTRDtrackV1::kGeometry, ily);
814 AliDebug(4, Form("Failed Geometry Matrix ly[%d]", ily));
817 matrix->LocalToMaster(loc, glb);
818 x = glb[0] - fgkMaxStep;
821 // check if track is well inside fiducial volume
822 if (!t.GetProlongation(x+fgkMaxStep, y, z)) {
824 t.SetStatus(AliTRDtrackV1::kProlongation);
825 AliDebug(4, Form("Failed Prolongation to x[%7.2f] y[%7.2f] z[%7.2f]", x+fgkMaxStep, y, z));
828 if(fGeom->IsOnBoundary(det, y, z, .5)){
829 t.SetStatus(AliTRDtrackV1::kBoundary, ily);
830 AliDebug(4, "Failed Track on Boundary");
833 // mark track as entering the FIDUCIAL volume of TRD
839 ptrTracklet = tracklets[ily];
840 if(!ptrTracklet){ // BUILD TRACKLET
841 AliDebug(3, Form("Building tracklet det[%d]", det));
842 // check data in supermodule
843 if(!fTrSec[sm].GetNChambers()){
844 t.SetStatus(AliTRDtrackV1::kNoClusters, ily);
845 AliDebug(4, "Failed NoClusters");
848 if(fTrSec[sm].GetX(ily) < 1.){
849 t.SetStatus(AliTRDtrackV1::kNoClusters, ily);
850 AliDebug(4, "Failed NoX");
854 // check data in chamber
855 if(!(chamber = fTrSec[sm].GetChamber(stk, ily))){
856 t.SetStatus(AliTRDtrackV1::kNoClusters, ily);
857 AliDebug(4, "Failed No Detector");
860 if(chamber->GetNClusters() < fgNTimeBins*fkRecoParam ->GetFindableClusters()){
861 t.SetStatus(AliTRDtrackV1::kNoClusters, ily);
862 AliDebug(4, "Failed Not Enough Clusters in Detector");
866 ptrTracklet = new(&tracklet) AliTRDseedV1(det);
867 ptrTracklet->SetReconstructor(fkReconstructor);
868 ptrTracklet->SetKink(t.IsKink());
869 ptrTracklet->SetPadPlane(fGeom->GetPadPlane(ily, stk));
870 ptrTracklet->SetX0(glb[0]+driftLength);
871 if(!tracklet.Init(&t)){
873 t.SetStatus(AliTRDtrackV1::kTrackletInit);
874 AliDebug(4, "Failed Tracklet Init");
877 if(!tracklet.AttachClusters(chamber, kTRUE)){
878 t.SetStatus(AliTRDtrackV1::kNoAttach, ily);
880 AliTRDseedV1 trackletCp(*ptrTracklet);
881 UChar_t status(t.GetStatusTRD(ily));
882 (*cstreamer) << "FollowBackProlongation2"
883 <<"status=" << status
884 <<"tracklet.=" << &trackletCp
887 AliDebug(4, "Failed Attach Clusters");
890 AliDebug(3, Form("Number of Clusters in Tracklet: %d", tracklet.GetN()));
891 if(tracklet.GetN() < fgNTimeBins*fkRecoParam ->GetFindableClusters()){
892 t.SetStatus(AliTRDtrackV1::kNoClustersTracklet, ily);
894 AliTRDseedV1 trackletCp(*ptrTracklet);
895 UChar_t status(t.GetStatusTRD(ily));
896 (*cstreamer) << "FollowBackProlongation2"
897 <<"status=" << status
898 <<"tracklet.=" << &trackletCp
901 AliDebug(4, "Failed N Clusters Attached");
904 ptrTracklet->UpdateUsed();
905 } else AliDebug(2, Form("Use external tracklet ly[%d]", ily));
906 // propagate track to the radial position of the tracklet
908 // fit tracklet no tilt correction
909 if(!ptrTracklet->Fit(kFALSE)){
910 t.SetStatus(AliTRDtrackV1::kNoFit, ily);
911 AliDebug(4, "Failed Tracklet Fit");
914 x = ptrTracklet->GetX(); //GetX0();
915 if(x > (fgkMaxStep + t.GetX()) && !PropagateToX(t, x, fgkMaxStep)) {
917 t.SetStatus(AliTRDtrackV1::kPropagation);
918 AliDebug(4, Form("Failed Propagation to Tracklet x[%7.2f]", x));
921 if(!AdjustSector(&t)) {
923 t.SetStatus(AliTRDtrackV1::kAdjustSector);
924 AliDebug(4, "Failed Adjust Sector");
927 if(TMath::Abs(t.GetSnp()) > fgkMaxSnp) {
929 t.SetStatus(AliTRDtrackV1::kSnp);
930 AliDebug(4, Form("Failed Max Snp[%f] MaxSnp[%f]", t.GetSnp(), fgkMaxSnp));
935 kPropagateIn = kFALSE;
937 Double_t cov[3]; ptrTracklet->GetCovAt(x, cov);
938 Double_t p[2] = { ptrTracklet->GetY(), ptrTracklet->GetZ()};
939 Double_t chi2 = ((AliExternalTrackParam)t).GetPredictedChi2(p, cov);
940 // update Kalman with the TRD measurement
941 if(chi2>1e+10){ // TODO
942 t.SetStatus(AliTRDtrackV1::kChi2, ily);
944 UChar_t status(t.GetStatusTRD());
945 AliTRDseedV1 trackletCp(*ptrTracklet);
946 AliTRDtrackV1 trackCp(t);
948 (*cstreamer) << "FollowBackProlongation1"
949 << "status=" << status
950 << "tracklet.=" << &trackletCp
951 << "track.=" << &trackCp
954 AliDebug(4, Form("Failed Chi2[%f]", chi2));
957 if(!t.Update(p, cov, chi2, kUseTRD)) {
959 t.SetStatus(AliTRDtrackV1::kUpdate);
961 UChar_t status(t.GetStatusTRD());
962 AliTRDseedV1 trackletCp(*ptrTracklet);
963 AliTRDtrackV1 trackCp(t);
965 (*cstreamer) << "FollowBackProlongation1"
966 << "status=" << status
967 << "tracklet.=" << &trackletCp
968 << "track.=" << &trackCp
971 AliDebug(4, Form("Failed Track Update @ y[%7.2f] z[%7.2f] s2y[%f] s2z[%f] covyz[%f]", p[0], p[1], cov[0], cov[2], cov[1]));
974 if(!kStandAlone) ptrTracklet->UseClusters();
976 AliTracker::FillResiduals(&t, p, cov, ptrTracklet->GetVolumeId());
979 // load tracklet to the tracker
980 ptrTracklet->Update(&t);
981 ptrTracklet = SetTracklet(ptrTracklet);
982 Int_t index(fTracklets->GetEntriesFast()-1);
983 t.SetTracklet(ptrTracklet, index);
984 n += ptrTracklet->GetN();
985 AliDebug(2, Form("Setting Tracklet[%d] @ Idx[%d]", ily, index));
987 // Reset material budget if 2 consecutive gold
988 // if(ilayer>0 && t.GetTracklet(ilayer-1) && ptrTracklet->GetN() + t.GetTracklet(ilayer-1)->GetN() > 20) t.SetBudget(2, 0.);
990 // Make backup of the track until is gold
992 if(!kStandAlone && (failed = t.MakeBackupTrack())) AliDebug(2, Form("Failed backup on cut[%d]", failed));
995 //printf("clusters[%d] chi2[%f] x[%f] status[%d ", n, t.GetChi2(), t.GetX(), t.GetStatusTRD());
996 //for(int i=0; i<6; i++) printf("%d ", t.GetStatusTRD(i)); printf("]\n");
999 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
1000 AliTRDtrackV1 track(t);
1002 (*cstreamer) << "FollowBackProlongation0"
1003 << "EventNumber=" << eventNumber
1005 << "track.=" << &track
1012 //_________________________________________________________________________
1013 Float_t AliTRDtrackerV1::FitRieman(AliTRDseedV1 *tracklets, Double_t *chi2, Int_t *const planes){
1015 // Fits a Riemann-circle to the given points without tilting pad correction.
1016 // The fit is performed using an instance of the class AliRieman (equations
1017 // and transformations see documentation of this class)
1018 // Afterwards all the tracklets are Updated
1020 // Parameters: - Array of tracklets (AliTRDseedV1)
1021 // - Storage for the chi2 values (beginning with direction z)
1022 // - Seeding configuration
1023 // Output: - The curvature
1025 AliRieman *fitter = AliTRDtrackerV1::GetRiemanFitter();
1027 Int_t allplanes[] = {0, 1, 2, 3, 4, 5};
1028 Int_t *ppl = &allplanes[0];
1029 Int_t maxLayers = 6;
1034 for(Int_t il = 0; il < maxLayers; il++){
1035 if(!tracklets[ppl[il]].IsOK()) continue;
1036 fitter->AddPoint(tracklets[ppl[il]].GetX0(), tracklets[ppl[il]].GetYfit(0), tracklets[ppl[il]].GetZfit(0),1,10);
1039 // Set the reference position of the fit and calculate the chi2 values
1040 memset(chi2, 0, sizeof(Double_t) * 2);
1041 for(Int_t il = 0; il < maxLayers; il++){
1042 // Reference positions
1043 tracklets[ppl[il]].Init(fitter);
1046 if((!tracklets[ppl[il]].IsOK()) && (!planes)) continue;
1047 chi2[0] += tracklets[ppl[il]].GetChi2Y();
1048 chi2[1] += tracklets[ppl[il]].GetChi2Z();
1050 return fitter->GetC();
1053 //_________________________________________________________________________
1054 void AliTRDtrackerV1::FitRieman(AliTRDcluster **seedcl, Double_t chi2[2])
1057 // Performs a Riemann helix fit using the seedclusters as spacepoints
1058 // Afterwards the chi2 values are calculated and the seeds are updated
1060 // Parameters: - The four seedclusters
1061 // - The tracklet array (AliTRDseedV1)
1062 // - The seeding configuration
1067 AliRieman *fitter = AliTRDtrackerV1::GetRiemanFitter();
1069 for(Int_t i = 0; i < 4; i++){
1070 fitter->AddPoint(seedcl[i]->GetX(), seedcl[i]->GetY(), seedcl[i]->GetZ(), 1., 10.);
1075 // Update the seed and calculated the chi2 value
1076 chi2[0] = 0; chi2[1] = 0;
1077 for(Int_t ipl = 0; ipl < kNSeedPlanes; ipl++){
1079 chi2[0] += (seedcl[ipl]->GetZ() - fitter->GetZat(seedcl[ipl]->GetX())) * (seedcl[ipl]->GetZ() - fitter->GetZat(seedcl[ipl]->GetX()));
1080 chi2[1] += (seedcl[ipl]->GetY() - fitter->GetYat(seedcl[ipl]->GetX())) * (seedcl[ipl]->GetY() - fitter->GetYat(seedcl[ipl]->GetX()));
1085 //_________________________________________________________________________
1086 Float_t AliTRDtrackerV1::FitTiltedRiemanConstraint(AliTRDseedV1 *tracklets, Double_t zVertex)
1089 // Fits a helix to the clusters. Pad tilting is considered. As constraint it is
1090 // assumed that the vertex position is set to 0.
1091 // This method is very usefull for high-pt particles
1092 // Basis for the fit: (x - x0)^2 + (y - y0)^2 - R^2 = 0
1093 // x0, y0: Center of the circle
1094 // Measured y-position: ymeas = y - tan(phiT)(zc - zt)
1095 // zc: center of the pad row
1096 // Equation which has to be fitted (after transformation):
1097 // a + b * u + e * v + 2*(ymeas + tan(phiT)(z - zVertex))*t = 0
1099 // t = 1/(x^2 + y^2)
1101 // v = 2 * x * tan(phiT) * t
1102 // Parameters in the equation:
1103 // a = -1/y0, b = x0/y0, e = dz/dx
1105 // The Curvature is calculated by the following equation:
1106 // - curv = a/Sqrt(b^2 + 1) = 1/R
1107 // Parameters: - the 6 tracklets
1108 // - the Vertex constraint
1109 // Output: - the Chi2 value of the track
1114 TLinearFitter *fitter = GetTiltedRiemanFitterConstraint();
1115 fitter->StoreData(kTRUE);
1116 fitter->ClearPoints();
1117 AliTRDcluster *cl = NULL;
1119 Float_t x, y, z, w, t, error, tilt;
1122 for(Int_t ilr = 0; ilr < AliTRDgeometry::kNlayer; ilr++){
1123 if(!tracklets[ilr].IsOK()) continue;
1124 for(Int_t itb = 0; itb < AliTRDseedV1::kNclusters; itb++){
1125 if(!tracklets[ilr].IsUsable(itb)) continue;
1126 cl = tracklets[ilr].GetClusters(itb);
1127 if(!cl->IsInChamber()) continue;
1128 if(cl->GetSigmaY2()<1.e-6 || cl->GetSigmaZ2()<1.e-6){
1129 if(AliLog::GetDebugLevel("TRD", "AliTRDtrackerV1")>1) printf("D-AliTRDtrackerV1::FitTiltedRiemanConstraint: Cluster error parameterization missing. This should appear only in HLT tests.");
1135 tilt = tracklets[ilr].GetTilt();
1137 t = 1./(x * x + y * y);
1138 uvt[0] = 2. * x * t;
1139 uvt[1] = 2. * x * t * tilt ;
1140 w = 2. * (y + tilt * (z - zVertex)) * t;
1141 error = 2. * TMath::Sqrt(cl->GetSigmaY2()+tilt*tilt*cl->GetSigmaZ2()) * t;
1142 fitter->AddPoint(uvt, w, error);
1148 // Calculate curvature
1149 Double_t a = fitter->GetParameter(0);
1150 Double_t b = fitter->GetParameter(1);
1151 Double_t curvature = a/TMath::Sqrt(b*b + 1);
1153 Float_t chi2track = fitter->GetChisquare()/Double_t(nPoints);
1154 for(Int_t ip = 0; ip < AliTRDtrackerV1::kNPlanes; ip++)
1155 tracklets[ip].SetC(curvature, 1);
1157 if(AliLog::GetDebugLevel("TRD", "AliTRDtrackerV1")>3) printf("D-AliTRDtrackerV1::FitTiltedRiemanConstraint: Chi2[%f] C[%5.2e] pt[%8.3f]\n", chi2track, curvature, GetBz()*kB2C/curvature);
1159 /* if(fkReconstructor->GetRecoParam()->GetStreamLevel(AliTRDrecoParam::kTracker()) >= 5){
1160 //Linear Model on z-direction
1161 Double_t xref = CalculateReferenceX(tracklets); // Relative to the middle of the stack
1162 Double_t slope = fitter->GetParameter(2);
1163 Double_t zref = slope * xref;
1164 Float_t chi2Z = CalculateChi2Z(tracklets, zref, slope, xref);
1165 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
1166 Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
1167 TTreeSRedirector &treeStreamer = *fkReconstructor->GetDebugStream(AliTRDReconstructor::kTracker);
1168 treeStreamer << "FitTiltedRiemanConstraint"
1169 << "EventNumber=" << eventNumber
1170 << "CandidateNumber=" << candidateNumber
1171 << "Curvature=" << curvature
1172 << "Chi2Track=" << chi2track
1173 << "Chi2Z=" << chi2Z
1180 //_________________________________________________________________________
1181 Float_t AliTRDtrackerV1::FitTiltedRieman(AliTRDseedV1 *tracklets, Bool_t sigError)
1184 // Performs a Riemann fit taking tilting pad correction into account
1185 // The equation of a Riemann circle, where the y position is substituted by the
1186 // measured y-position taking pad tilting into account, has to be transformed
1187 // into a 4-dimensional hyperplane equation
1188 // Riemann circle: (x-x0)^2 + (y-y0)^2 -R^2 = 0
1189 // Measured y-Position: ymeas = y - tan(phiT)(zc - zt)
1190 // zc: center of the pad row
1191 // zt: z-position of the track
1192 // The z-position of the track is assumed to be linear dependent on the x-position
1193 // Transformed equation: a + b * u + c * t + d * v + e * w - 2 * (ymeas + tan(phiT) * zc) * t = 0
1194 // Transformation: u = 2 * x * t
1195 // v = 2 * tan(phiT) * t
1196 // w = 2 * tan(phiT) * (x - xref) * t
1197 // t = 1 / (x^2 + ymeas^2)
1198 // Parameters: a = -1/y0
1200 // c = (R^2 -x0^2 - y0^2)/y0
1203 // If the offset respectively the slope in z-position is impossible, the parameters are fixed using
1204 // results from the simple riemann fit. Afterwards the fit is redone.
1205 // The curvature is calculated according to the formula:
1206 // curv = a/(1 + b^2 + c*a) = 1/R
1208 // Paramters: - Array of tracklets (connected to the track candidate)
1209 // - Flag selecting the error definition
1210 // Output: - Chi2 values of the track (in Parameter list)
1212 TLinearFitter *fitter = GetTiltedRiemanFitter();
1213 fitter->StoreData(kTRUE);
1214 fitter->ClearPoints();
1215 AliTRDLeastSquare zfitter;
1216 AliTRDcluster *cl = NULL;
1218 Double_t xref = CalculateReferenceX(tracklets);
1219 Double_t x, y, z, t, tilt, dx, w, we, erry, errz;
1220 Double_t uvt[4], sumPolY[5], sumPolZ[3];
1221 memset(sumPolY, 0, sizeof(Double_t) * 5);
1222 memset(sumPolZ, 0, sizeof(Double_t) * 3);
1224 // Containers for Least-square fitter
1225 for(Int_t ipl = 0; ipl < kNPlanes; ipl++){
1226 if(!tracklets[ipl].IsOK()) continue;
1227 tilt = tracklets[ipl].GetTilt();
1228 for(Int_t itb = 0; itb < AliTRDseedV1::kNclusters; itb++){
1229 if(!(cl = tracklets[ipl].GetClusters(itb))) continue;
1230 if(!cl->IsInChamber()) continue;
1231 if (!tracklets[ipl].IsUsable(itb)) continue;
1235 if(cl->GetSigmaY2()<1.e-6 || cl->GetSigmaZ2()<1.e-6){
1236 if(AliLog::GetDebugLevel("TRD", "AliTRDtrackerV1")>1) printf("D-AliTRDtrackerV1::FitTiltedRieman: Cluster error parameterization missing. This should appear only in HLT tests.");
1237 tracklets[ipl].Print("a");
1243 uvt[0] = 2. * x * t;
1245 uvt[2] = 2. * tilt * t;
1246 uvt[3] = 2. * tilt * dx * t;
1247 w = 2. * (y + tilt*z) * t;
1248 // error definition changes for the different calls
1250 we *= sigError ? TMath::Sqrt(cl->GetSigmaY2()+tilt*tilt*cl->GetSigmaZ2()) : 0.2;
1251 fitter->AddPoint(uvt, w, we);
1252 zfitter.AddPoint(&x, z, static_cast<Double_t>(TMath::Sqrt(cl->GetSigmaZ2())));
1253 // adding points for covariance matrix estimation
1254 erry = 1./(TMath::Sqrt(cl->GetSigmaY2()) + 0.1); // 0.1 is a systematic error (due to misalignment and miscalibration)
1256 errz = 1./cl->GetSigmaZ2();
1257 for(Int_t ipol = 0; ipol < 5; ipol++){
1258 sumPolY[ipol] += erry;
1261 sumPolZ[ipol] += errz;
1271 Double_t offset = fitter->GetParameter(3);
1272 Double_t slope = fitter->GetParameter(4);
1274 // Linear fitter - not possible to make boundaries
1275 // Do not accept non possible z and dzdx combinations
1276 Bool_t acceptablez = kTRUE;
1277 Double_t zref = 0.0;
1278 for (Int_t iLayer = 0; iLayer < kNPlanes; iLayer++) {
1279 if(!tracklets[iLayer].IsOK()) continue;
1280 zref = offset + slope * (tracklets[iLayer].GetX0() - xref);
1281 if (TMath::Abs(tracklets[iLayer].GetZfit(0) - zref) > tracklets[iLayer].GetPadLength() * 0.5 + 1.0)
1282 acceptablez = kFALSE;
1285 Double_t dzmf = zfitter.GetFunctionParameter(1);
1286 Double_t zmf = zfitter.GetFunctionValue(&xref);
1287 fgTiltedRieman->FixParameter(3, zmf);
1288 fgTiltedRieman->FixParameter(4, dzmf);
1290 fitter->ReleaseParameter(3);
1291 fitter->ReleaseParameter(4);
1292 offset = fitter->GetParameter(3);
1293 slope = fitter->GetParameter(4);
1296 // Calculate Curvarture
1297 Double_t a = fitter->GetParameter(0);
1298 Double_t b = fitter->GetParameter(1);
1299 Double_t c = fitter->GetParameter(2);
1300 Double_t curvature = 1.0 + b*b - c*a;
1301 if (curvature > 0.0) curvature = a / TMath::Sqrt(curvature);
1303 Double_t chi2track = fitter->GetChisquare()/Double_t(nPoints);
1305 // Prepare error calculation
1306 TMatrixD covarPolY(3,3);
1307 covarPolY(0,0) = sumPolY[0]; covarPolY(1,1) = sumPolY[2]; covarPolY(2,2) = sumPolY[4];
1308 covarPolY(0,1) = covarPolY(1,0) = sumPolY[1];
1309 covarPolY(0,2) = covarPolY(2,0) = sumPolY[2];
1310 covarPolY(2,1) = covarPolY(1,2) = sumPolY[3];
1312 TMatrixD covarPolZ(2,2);
1313 covarPolZ(0,0) = sumPolZ[0]; covarPolZ(1,1) = sumPolZ[2];
1314 covarPolZ(1,0) = covarPolZ(0,1) = sumPolZ[1];
1317 // Update the tracklets
1318 Double_t x1, dy, dz;
1320 memset(cov, 0, sizeof(Double_t) * 15);
1321 for(Int_t iLayer = 0; iLayer < AliTRDtrackerV1::kNPlanes; iLayer++) {
1323 x = tracklets[iLayer].GetX0();
1329 memset(cov, 0, sizeof(Double_t) * 3);
1330 TMatrixD transform(3,3);
1333 transform(0,2) = x*x;
1337 TMatrixD covariance(transform, TMatrixD::kMult, covarPolY);
1338 covariance *= transform.T();
1339 TMatrixD transformZ(2,2);
1340 transformZ(0,0) = transformZ(1,1) = 1;
1341 transformZ(0,1) = x;
1342 TMatrixD covarZ(transformZ, TMatrixD::kMult, covarPolZ);
1343 covarZ *= transformZ.T();
1344 // y: R^2 = (x - x0)^2 + (y - y0)^2
1345 // => y = y0 +/- Sqrt(R^2 - (x - x0)^2)
1346 // R = Sqrt() = 1/Curvature
1347 // => y = y0 +/- Sqrt(1/Curvature^2 - (x - x0)^2)
1348 Double_t res = (x * a + b); // = (x - x0)/y0
1350 res = 1.0 - c * a + b * b - res; // = (R^2 - (x - x0)^2)/y0^2
1352 res = TMath::Sqrt(res);
1353 y = (1.0 - res) / a;
1355 cov[0] = covariance(0,0);
1356 cov[2] = covarZ(0,0);
1359 // dy: R^2 = (x - x0)^2 + (y - y0)^2
1360 // => y = +/- Sqrt(R^2 - (x - x0)^2) + y0
1361 // => dy/dx = (x - x0)/Sqrt(R^2 - (x - x0)^2)
1362 // Curvature: cr = 1/R = a/Sqrt(1 + b^2 - c*a)
1363 // => dy/dx = (x - x0)/(1/(cr^2) - (x - x0)^2)
1364 Double_t x0 = -b / a;
1365 if (-c * a + b * b + 1 > 0) {
1366 if (1.0/(curvature * curvature) - (x - x0) * (x - x0) > 0.0) {
1367 Double_t yderiv = (x - x0) / TMath::Sqrt(1.0/(curvature * curvature) - (x - x0) * (x - x0));
1368 if (a < 0) yderiv *= -1.0;
1372 z = offset + slope * (x - xref);
1374 tracklets[iLayer].SetYref(0, y);
1375 tracklets[iLayer].SetYref(1, dy);
1376 tracklets[iLayer].SetZref(0, z);
1377 tracklets[iLayer].SetZref(1, dz);
1378 tracklets[iLayer].SetC(curvature);
1379 tracklets[iLayer].SetCovRef(cov);
1380 tracklets[iLayer].SetChi2(chi2track);
1382 if(AliLog::GetDebugLevel("TRD", "AliTRDtrackerV1")>3) printf("D-AliTRDtrackerV1::FitTiltedRieman: Chi2[%f] C[%5.2e] pt[%8.3f]\n", chi2track, curvature, GetBz()*kB2C/curvature);
1384 /* if(fkReconstructor->GetRecoParam()->GetStreamLevel(AliTRDrecoParam::kTracker) >=5){
1385 TTreeSRedirector &cstreamer = *fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker);
1386 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
1387 Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
1388 Double_t chi2z = CalculateChi2Z(tracklets, offset, slope, xref);
1389 cstreamer << "FitTiltedRieman0"
1390 << "EventNumber=" << eventNumber
1391 << "CandidateNumber=" << candidateNumber
1393 << "Chi2Z=" << chi2z
1400 //____________________________________________________________________
1401 Double_t AliTRDtrackerV1::FitLine(const AliTRDtrackV1 *track, AliTRDseedV1 *tracklets, Bool_t err, Int_t np, AliTrackPoint *points)
1404 // Fit track with a staight line
1405 // Fills an AliTrackPoint array with np points
1406 // Function should be used to refit tracks when no magnetic field was on
1408 AliTRDLeastSquare yfitter, zfitter;
1409 AliTRDcluster *cl = NULL;
1411 AliTRDseedV1 work[kNPlanes], *tracklet = NULL;
1413 for(Int_t ipl = 0; ipl < kNPlanes; ipl++){
1414 if(!(tracklet = track->GetTracklet(ipl))) continue;
1415 if(!tracklet->IsOK()) continue;
1416 new(&work[ipl]) AliTRDseedV1(*tracklet);
1418 tracklets = &work[0];
1421 Double_t xref = CalculateReferenceX(tracklets);
1422 Double_t x, y, z, dx, ye, yr, tilt;
1423 for(Int_t ipl = 0; ipl < kNPlanes; ipl++){
1424 if(!tracklets[ipl].IsOK()) continue;
1425 for(Int_t itb = 0; itb < fgNTimeBins; itb++){
1426 if(!(cl = tracklets[ipl].GetClusters(itb))) continue;
1427 if (!tracklets[ipl].IsUsable(itb)) continue;
1431 zfitter.AddPoint(&dx, z, static_cast<Double_t>(TMath::Sqrt(cl->GetSigmaZ2())));
1435 Double_t z0 = zfitter.GetFunctionParameter(0);
1436 Double_t dzdx = zfitter.GetFunctionParameter(1);
1437 for(Int_t ipl = 0; ipl < kNPlanes; ipl++){
1438 if(!tracklets[ipl].IsOK()) continue;
1439 for(Int_t itb = 0; itb < fgNTimeBins; itb++){
1440 if(!(cl = tracklets[ipl].GetClusters(itb))) continue;
1441 if (!tracklets[ipl].IsUsable(itb)) continue;
1445 tilt = tracklets[ipl].GetTilt();
1447 yr = y + tilt*(z - z0 - dzdx*dx);
1448 // error definition changes for the different calls
1449 ye = tilt*TMath::Sqrt(cl->GetSigmaZ2());
1450 ye += err ? tracklets[ipl].GetSigmaY() : 0.2;
1451 yfitter.AddPoint(&dx, yr, ye);
1455 Double_t y0 = yfitter.GetFunctionParameter(0);
1456 Double_t dydx = yfitter.GetFunctionParameter(1);
1457 Double_t chi2 = 0.;//yfitter.GetChisquare()/Double_t(nPoints);
1459 //update track points array
1462 for(int ip=0; ip<np; ip++){
1463 points[ip].GetXYZ(xyz);
1464 xyz[1] = y0 + dydx * (xyz[0] - xref);
1465 xyz[2] = z0 + dzdx * (xyz[0] - xref);
1466 points[ip].SetXYZ(xyz);
1473 //_________________________________________________________________________
1474 Double_t AliTRDtrackerV1::FitRiemanTilt(const AliTRDtrackV1 *track, AliTRDseedV1 *tracklets, Bool_t sigError, Int_t np, AliTrackPoint *points)
1477 // Performs a Riemann fit taking tilting pad correction into account
1479 // Paramters: - Array of tracklets (connected to the track candidate)
1480 // - Flag selecting the error definition
1481 // Output: - Chi2 values of the track (in Parameter list)
1483 // The equations which has to be solved simultaneously are:
1485 // R^{2} = (x-x_{0})^{2} + (y^{*}-y_{0})^{2}
1486 // y^{*} = y - tg(h)(z - z_{t})
1487 // z_{t} = z_{0}+dzdx*(x-x_{r})
1489 // with (x, y, z) the coordinate of the cluster, (x_0, y_0, z_0) the coordinate of the center of the Riemann circle,
1490 // R its radius, x_r a constant refrence radial position in the middle of the TRD stack and dzdx the slope of the
1491 // track in the x-z plane. Using the following transformations
1493 // t = 1 / (x^{2} + y^{2})
1495 // v = 2 * tan(h) * t
1496 // w = 2 * tan(h) * (x - x_{r}) * t
1498 // One gets the following linear equation
1500 // a + b * u + c * t + d * v + e * w = 2 * (y + tg(h) * z) * t
1502 // where the coefficients have the following meaning
1506 // c = (R^{2} -x_{0}^{2} - y_{0}^{2})/y_{0}
1510 // The error calculation for the free term is thus
1512 // #sigma = 2 * #sqrt{#sigma^{2}_{y} + (tilt corr ...) + tg^{2}(h) * #sigma^{2}_{z}} * t
1515 // From this simple model one can compute chi^2 estimates and a rough approximation of pt from the curvature according
1518 // C = 1/R = a/(1 + b^{2} + c*a)
1522 // M.Ivanov <M.Ivanov@gsi.de>
1523 // A.Bercuci <A.Bercuci@gsi.de>
1524 // M.Fasel <M.Fasel@gsi.de>
1526 TLinearFitter *fitter = GetTiltedRiemanFitter();
1527 fitter->StoreData(kTRUE);
1528 fitter->ClearPoints();
1529 AliTRDLeastSquare zfitter;
1530 AliTRDcluster *cl = NULL;
1532 AliTRDseedV1 work[kNPlanes], *tracklet = NULL;
1534 for(Int_t ipl = 0; ipl < kNPlanes; ipl++){
1535 if(!(tracklet = track->GetTracklet(ipl))) continue;
1536 if(!tracklet->IsOK()) continue;
1537 new(&work[ipl]) AliTRDseedV1(*tracklet);
1539 tracklets = &work[0];
1542 Double_t xref = CalculateReferenceX(tracklets);
1543 if(AliLog::GetDebugLevel("TRD", "AliTRDtrackerV1")>3) printf("D-AliTRDtrackerV1::FitRiemanTilt:\nx0[(0)%6.2f (1)%6.2f (2)%6.2f (3)%6.2f (4)%6.2f (5)%6.2f] xref[%6.2f]", tracklets[0].GetX0(), tracklets[1].GetX0(), tracklets[2].GetX0(), tracklets[3].GetX0(), tracklets[4].GetX0(), tracklets[5].GetX0(), xref);
1544 Double_t x, y, z, t, tilt, dx, w, we;
1547 // Containers for Least-square fitter
1548 for(Int_t ipl = 0; ipl < kNPlanes; ipl++){
1549 if(!tracklets[ipl].IsOK()) continue;
1550 for(Int_t itb = 0; itb < AliTRDseedV1::kNclusters; itb++){
1551 if(!(cl = tracklets[ipl].GetClusters(itb))) continue;
1552 //if (!tracklets[ipl].IsUsable(itb)) continue;
1556 tilt = tracklets[ipl].GetTilt();
1560 uvt[0] = 2. * x * t;
1562 uvt[2] = 2. * tilt * t;
1563 uvt[3] = 2. * tilt * dx * t;
1564 w = 2. * (y + tilt*z) * t;
1565 // error definition changes for the different calls
1567 we *= sigError ? TMath::Sqrt(cl->GetSigmaY2()) : 0.2;
1568 fitter->AddPoint(uvt, w, we);
1569 zfitter.AddPoint(&x, z, static_cast<Double_t>(TMath::Sqrt(cl->GetSigmaZ2())));
1573 if(fitter->Eval()) return 1.E10;
1575 Double_t z0 = fitter->GetParameter(3);
1576 Double_t dzdx = fitter->GetParameter(4);
1579 // Linear fitter - not possible to make boundaries
1580 // Do not accept non possible z and dzdx combinations
1581 Bool_t accept = kTRUE;
1582 Double_t zref = 0.0;
1583 for (Int_t iLayer = 0; iLayer < kNPlanes; iLayer++) {
1584 if(!tracklets[iLayer].IsOK()) continue;
1585 zref = z0 + dzdx * (tracklets[iLayer].GetX0() - xref);
1586 if (TMath::Abs(tracklets[iLayer].GetZfit(0) - zref) > tracklets[iLayer].GetPadLength() * 0.5 + 1.0)
1591 Double_t dzmf = zfitter.GetFunctionParameter(1);
1592 Double_t zmf = zfitter.GetFunctionValue(&xref);
1593 fitter->FixParameter(3, zmf);
1594 fitter->FixParameter(4, dzmf);
1596 fitter->ReleaseParameter(3);
1597 fitter->ReleaseParameter(4);
1598 z0 = fitter->GetParameter(3); // = zmf ?
1599 dzdx = fitter->GetParameter(4); // = dzmf ?
1602 // Calculate Curvature
1603 Double_t a = fitter->GetParameter(0);
1604 Double_t b = fitter->GetParameter(1);
1605 Double_t c = fitter->GetParameter(2);
1606 Double_t y0 = 1. / a;
1607 Double_t x0 = -b * y0;
1608 Double_t tmp = y0*y0 + x0*x0 - c*y0;
1609 if(tmp<=0.) return 1.E10;
1610 Double_t radius = TMath::Sqrt(tmp);
1611 Double_t curvature = 1.0 + b*b - c*a;
1612 if (curvature > 0.0) curvature = a / TMath::Sqrt(curvature);
1614 // Calculate chi2 of the fit
1615 Double_t chi2 = fitter->GetChisquare()/Double_t(nPoints);
1616 if(AliLog::GetDebugLevel("TRD", "AliTRDtrackerV1")>3) printf("D-AliTRDtrackerV1::FitRiemanTilt:x0[%6.2f] y0[%6.2f] R[%6.2f] chi2[%f]\n", x0, y0, radius, chi2);
1618 // Update the tracklets
1620 for(Int_t ip = 0; ip < kNPlanes; ip++) {
1621 x = tracklets[ip].GetX0();
1622 tmp = radius*radius-(x-x0)*(x-x0);
1623 if(tmp <= 0.) continue;
1624 tmp = TMath::Sqrt(tmp);
1626 // y: R^2 = (x - x0)^2 + (y - y0)^2
1627 // => y = y0 +/- Sqrt(R^2 - (x - x0)^2)
1628 tracklets[ip].SetYref(0, y0 - (y0>0.?1.:-1)*tmp);
1629 // => dy/dx = (x - x0)/Sqrt(R^2 - (x - x0)^2)
1630 tracklets[ip].SetYref(1, (x - x0) / tmp);
1631 tracklets[ip].SetZref(0, z0 + dzdx * (x - xref));
1632 tracklets[ip].SetZref(1, dzdx);
1633 tracklets[ip].SetC(curvature);
1634 tracklets[ip].SetChi2(chi2);
1637 //update track points array
1640 for(int ip=0; ip<np; ip++){
1641 points[ip].GetXYZ(xyz);
1642 xyz[1] = TMath::Abs(xyz[0] - x0) > radius ? 100. : y0 - (y0>0.?1.:-1.)*TMath::Sqrt((radius-(xyz[0]-x0))*(radius+(xyz[0]-x0)));
1643 xyz[2] = z0 + dzdx * (xyz[0] - xref);
1644 points[ip].SetXYZ(xyz);
1652 //____________________________________________________________________
1653 Double_t AliTRDtrackerV1::FitKalman(AliTRDtrackV1 *track, AliTRDseedV1 * const tracklets, Bool_t up, Int_t np, AliTrackPoint *points)
1655 // Kalman filter implementation for the TRD.
1656 // It returns the positions of the fit in the array "points"
1658 // Author : A.Bercuci@gsi.de
1660 // printf("Start track @ x[%f]\n", track->GetX());
1662 //prepare marker points along the track
1663 Int_t ip = np ? 0 : 1;
1665 if((up?-1:1) * (track->GetX() - points[ip].GetX()) > 0.) break;
1666 //printf("AliTRDtrackerV1::FitKalman() : Skip track marker x[%d] = %7.3f. Before track start ( %7.3f ).\n", ip, points[ip].GetX(), track->GetX());
1669 //if(points) printf("First marker point @ x[%d] = %f\n", ip, points[ip].GetX());
1672 AliTRDseedV1 tracklet, *ptrTracklet = NULL;
1674 //Loop through the TRD planes
1675 for (Int_t jplane = 0; jplane < kNPlanes; jplane++) {
1676 // GET TRACKLET OR BUILT IT
1677 Int_t iplane = up ? jplane : kNPlanes - 1 - jplane;
1679 if(!(ptrTracklet = &tracklets[iplane])) continue;
1681 if(!(ptrTracklet = track->GetTracklet(iplane))){
1682 /*AliTRDtrackerV1 *tracker = NULL;
1683 if(!(tracker = dynamic_cast<AliTRDtrackerV1*>( AliTRDrecoParam:Tracker()))) continue;
1684 ptrTracklet = new(&tracklet) AliTRDseedV1(iplane);
1685 if(!tracker->MakeTracklet(ptrTracklet, track)) */
1689 if(!ptrTracklet->IsOK()) continue;
1691 Double_t x = ptrTracklet->GetX0();
1694 //don't do anything if next marker is after next update point.
1695 if((up?-1:1) * (points[ip].GetX() - x) - fgkMaxStep < 0) break;
1696 if(((up?-1:1) * (points[ip].GetX() - track->GetX()) < 0) && !PropagateToX(*track, points[ip].GetX(), fgkMaxStep)) return -1.;
1698 Double_t xyz[3]; // should also get the covariance
1700 track->Global2LocalPosition(xyz, track->GetAlpha());
1701 points[ip].SetXYZ(xyz[0], xyz[1], xyz[2]);
1704 // printf("plane[%d] tracklet[%p] x[%f]\n", iplane, ptrTracklet, x);
1706 // Propagate closer to the next update point
1707 if(((up?-1:1) * (x - track->GetX()) + fgkMaxStep < 0) && !PropagateToX(*track, x + (up?-1:1)*fgkMaxStep, fgkMaxStep)) return -1.;
1709 if(!AdjustSector(track)) return -1;
1710 if(TMath::Abs(track->GetSnp()) > fgkMaxSnp) return -1;
1712 //load tracklet to the tracker and the track
1714 if((index = FindTracklet(ptrTracklet)) < 0){
1715 ptrTracklet = SetTracklet(&tracklet);
1716 index = fTracklets->GetEntriesFast()-1;
1718 track->SetTracklet(ptrTracklet, index);*/
1721 // register tracklet to track with tracklet creation !!
1722 // PropagateBack : loaded tracklet to the tracker and update index
1723 // RefitInward : update index
1724 // MakeTrack : loaded tracklet to the tracker and update index
1725 if(!tracklets) track->SetTracklet(ptrTracklet, -1);
1728 //Calculate the mean material budget along the path inside the chamber
1729 Double_t xyz0[3]; track->GetXYZ(xyz0);
1730 Double_t alpha = track->GetAlpha();
1731 Double_t xyz1[3], y, z;
1732 if(!track->GetProlongation(x, y, z)) return -1;
1733 xyz1[0] = x * TMath::Cos(alpha) - y * TMath::Sin(alpha);
1734 xyz1[1] = +x * TMath::Sin(alpha) + y * TMath::Cos(alpha);
1736 if(TMath::Abs(xyz0[0] - xyz1[0]) < 1e-3 && TMath::Abs(xyz0[1] - xyz1[1]) < 1e-3) continue; // check wheter we are at the same global x position
1738 if(AliTracker::MeanMaterialBudget(xyz0, xyz1, param) <=0.) break;
1739 Double_t xrho = param[0]*param[4]; // density*length
1740 Double_t xx0 = param[1]; // radiation length
1742 //Propagate the track
1743 track->PropagateTo(x, xx0, xrho);
1744 if (!AdjustSector(track)) break;
1747 Double_t cov[3]; ptrTracklet->GetCovAt(x, cov);
1748 Double_t p[2] = { ptrTracklet->GetY(), ptrTracklet->GetZ()};
1749 Double_t chi2 = ((AliExternalTrackParam*)track)->GetPredictedChi2(p, cov);
1750 if(chi2<1e+10) track->Update(p, cov, chi2);
1753 //Reset material budget if 2 consecutive gold
1754 if(iplane>0 && track->GetTracklet(iplane-1) && ptrTracklet->GetN() + track->GetTracklet(iplane-1)->GetN() > 20) track->SetBudget(2, 0.);
1755 } // end planes loop
1759 if(((up?-1:1) * (points[ip].GetX() - track->GetX()) < 0) && !PropagateToX(*track, points[ip].GetX(), fgkMaxStep)) return -1.;
1761 Double_t xyz[3]; // should also get the covariance
1763 track->Global2LocalPosition(xyz, track->GetAlpha());
1764 points[ip].SetXYZ(xyz[0], xyz[1], xyz[2]);
1768 return track->GetChi2();
1771 //_________________________________________________________________________
1772 Float_t AliTRDtrackerV1::CalculateChi2Z(AliTRDseedV1 *tracklets, Double_t offset, Double_t slope, Double_t xref)
1775 // Calculates the chi2-value of the track in z-Direction including tilting pad correction.
1776 // A linear dependence on the x-value serves as a model.
1777 // The parameters are related to the tilted Riemann fit.
1778 // Parameters: - Array of tracklets (AliTRDseedV1) related to the track candidate
1779 // - the offset for the reference x
1781 // - the reference x position
1782 // Output: - The Chi2 value of the track in z-Direction
1784 Float_t chi2Z = 0, nLayers = 0;
1785 for (Int_t iLayer = 0; iLayer < AliTRDgeometry::kNlayer; iLayer++) {
1786 if(!tracklets[iLayer].IsOK()) continue;
1787 Double_t z = offset + slope * (tracklets[iLayer].GetX0() - xref);
1788 chi2Z += TMath::Abs(tracklets[iLayer].GetZfit(0) - z);
1791 chi2Z /= TMath::Max((nLayers - 3.0),1.0);
1795 //_____________________________________________________________________________
1796 Int_t AliTRDtrackerV1::PropagateToX(AliTRDtrackV1 &t, Double_t xToGo, Double_t maxStep)
1799 // Starting from current X-position of track <t> this function
1800 // extrapolates the track up to radial position <xToGo>.
1801 // Returns 1 if track reaches the plane, and 0 otherwise
1804 const Double_t kEpsilon = 0.00001;
1806 // Current track X-position
1807 Double_t xpos = t.GetX();
1809 // Direction: inward or outward
1810 Double_t dir = (xpos < xToGo) ? 1.0 : -1.0;
1812 while (((xToGo - xpos) * dir) > kEpsilon) {
1821 // The next step size
1822 Double_t step = dir * TMath::Min(TMath::Abs(xToGo-xpos),maxStep);
1824 // Get the global position of the starting point
1827 // X-position after next step
1830 // Get local Y and Z at the X-position of the next step
1831 if(t.GetProlongation(x,y,z)<0) return 0; // No prolongation possible
1833 // The global position of the end point of this prolongation step
1834 xyz1[0] = x * TMath::Cos(t.GetAlpha()) - y * TMath::Sin(t.GetAlpha());
1835 xyz1[1] = +x * TMath::Sin(t.GetAlpha()) + y * TMath::Cos(t.GetAlpha());
1838 // Calculate the mean material budget between start and
1839 // end point of this prolongation step
1840 if(AliTracker::MeanMaterialBudget(xyz0, xyz1, param)<=0.) return 0;
1842 // Propagate the track to the X-position after the next step
1843 if (!t.PropagateTo(x, param[1], param[0]*param[4])) return 0;
1845 // Rotate the track if necessary
1848 // New track X-position
1858 //_____________________________________________________________________________
1859 Int_t AliTRDtrackerV1::ReadClusters(TClonesArray* &array, TTree *clusterTree) const
1862 // Reads AliTRDclusters from the file.
1863 // The names of the cluster tree and branches
1864 // should match the ones used in AliTRDclusterizer::WriteClusters()
1867 Int_t nsize = Int_t(clusterTree->GetTotBytes() / (sizeof(AliTRDcluster)));
1868 TObjArray *clusterArray = new TObjArray(nsize+1000);
1870 TBranch *branch = clusterTree->GetBranch("TRDcluster");
1872 AliError("Can't get the branch !");
1875 branch->SetAddress(&clusterArray);
1878 Float_t nclusters = fkRecoParam->GetNClusters();
1879 if(fkReconstructor->IsHLT()) nclusters /= AliTRDgeometry::kNsector;
1880 array = new TClonesArray("AliTRDcluster", Int_t(nclusters));
1881 array->SetOwner(kTRUE);
1884 // Loop through all entries in the tree
1885 Int_t nEntries = (Int_t) clusterTree->GetEntries();
1888 AliTRDcluster *c = NULL;
1889 for (Int_t iEntry = 0; iEntry < nEntries; iEntry++) {
1891 nbytes += clusterTree->GetEvent(iEntry);
1893 // Get the number of points in the detector
1894 Int_t nCluster = clusterArray->GetEntriesFast();
1895 for (Int_t iCluster = 0; iCluster < nCluster; iCluster++) {
1896 if(!(c = (AliTRDcluster *) clusterArray->UncheckedAt(iCluster))) continue;
1897 new((*fClusters)[ncl++]) AliTRDcluster(*c);
1898 delete (clusterArray->RemoveAt(iCluster));
1902 delete clusterArray;
1907 //_____________________________________________________________________________
1908 Int_t AliTRDtrackerV1::LoadClusters(TTree *cTree)
1911 // Fills clusters into TRD tracking sectors
1914 fkRecoParam = fkReconstructor->GetRecoParam(); // load reco param for this event
1916 if(!fkReconstructor->IsWritingClusters()){
1917 fClusters = AliTRDReconstructor::GetClusters();
1919 if (ReadClusters(fClusters, cTree)) {
1920 AliError("Problem with reading the clusters !");
1926 if(!fClusters || !fClusters->GetEntriesFast()){
1927 AliInfo("No TRD clusters");
1932 BuildTrackingContainers();
1934 //Int_t ncl = fClusters->GetEntriesFast();
1935 //AliInfo(Form("Clusters %d [%6.2f %% in the active volume]", ncl, 100.*float(nin)/ncl));
1940 //_____________________________________________________________________________
1941 Int_t AliTRDtrackerV1::LoadClusters(TClonesArray * const clusters)
1944 // Fills clusters into TRD tracking sectors
1945 // Function for use in the HLT
1947 if(!clusters || !clusters->GetEntriesFast()){
1948 AliInfo("No TRD clusters");
1952 fClusters = clusters;
1955 fkRecoParam = fkReconstructor->GetRecoParam(); // load reco param for this event
1956 BuildTrackingContainers();
1958 //Int_t ncl = fClusters->GetEntriesFast();
1959 //AliInfo(Form("Clusters %d [%6.2f %% in the active volume]", ncl, 100.*float(nin)/ncl));
1965 //____________________________________________________________________
1966 Int_t AliTRDtrackerV1::BuildTrackingContainers()
1968 // Building tracking containers for clusters
1970 Int_t nin(0), ncl(fClusters->GetEntriesFast());
1972 AliTRDcluster *c = (AliTRDcluster *) fClusters->UncheckedAt(ncl);
1973 if(c->IsInChamber()) nin++;
1974 if(fkReconstructor->IsHLT()) c->SetRPhiMethod(AliTRDcluster::kCOG);
1975 Int_t detector = c->GetDetector();
1976 Int_t sector = fGeom->GetSector(detector);
1977 Int_t stack = fGeom->GetStack(detector);
1978 Int_t layer = fGeom->GetLayer(detector);
1980 fTrSec[sector].GetChamber(stack, layer, kTRUE)->InsertCluster(c, ncl, fkReconstructor->IsHLT());
1983 for(int isector =0; isector<AliTRDgeometry::kNsector; isector++){
1984 if(!fTrSec[isector].GetNChambers()) continue;
1985 fTrSec[isector].Init(fkReconstructor);
1993 //____________________________________________________________________
1994 void AliTRDtrackerV1::UnloadClusters()
1997 // Clears the arrays of clusters and tracks. Resets sectors and timebins
1998 // If option "force" is also set the containers are also deleted. This is useful
2003 if(HasRemoveContainers()){delete fTracks; fTracks = NULL;}
2006 fTracklets->Delete();
2007 if(HasRemoveContainers()){delete fTracklets; fTracklets = NULL;}
2010 if(IsClustersOwner()) fClusters->Delete();
2012 // save clusters array in the reconstructor for further use.
2013 if(!fkReconstructor->IsWritingClusters()){
2014 AliTRDReconstructor::SetClusters(fClusters);
2015 SetClustersOwner(kFALSE);
2016 } else AliTRDReconstructor::SetClusters(NULL);
2019 for (int i = 0; i < AliTRDgeometry::kNsector; i++) fTrSec[i].Clear();
2021 // Increment the Event Number
2022 AliTRDtrackerDebug::SetEventNumber(AliTRDtrackerDebug::GetEventNumber() + 1);
2025 // //____________________________________________________________________
2026 // void AliTRDtrackerV1::UseClusters(const AliKalmanTrack *t, Int_t) const
2028 // const AliTRDtrackV1 *track = dynamic_cast<const AliTRDtrackV1*>(t);
2029 // if(!track) return;
2031 // AliTRDseedV1 *tracklet = NULL;
2032 // for(Int_t ily=AliTRDgeometry::kNlayer; ily--;){
2033 // if(!(tracklet = track->GetTracklet(ily))) continue;
2034 // AliTRDcluster *c = NULL;
2035 // for(Int_t ic=AliTRDseed::kNclusters; ic--;){
2036 // if(!(c=tracklet->GetClusters(ic))) continue;
2043 //_____________________________________________________________________________
2044 Bool_t AliTRDtrackerV1::AdjustSector(AliTRDtrackV1 *const track)
2047 // Rotates the track when necessary
2050 Double_t alpha = AliTRDgeometry::GetAlpha();
2051 Double_t y = track->GetY();
2052 Double_t ymax = track->GetX()*TMath::Tan(0.5*alpha);
2055 if (!track->Rotate( alpha)) {
2059 else if (y < -ymax) {
2060 if (!track->Rotate(-alpha)) {
2070 //____________________________________________________________________
2071 AliTRDseedV1* AliTRDtrackerV1::GetTracklet(AliTRDtrackV1 *const track, Int_t p, Int_t &idx)
2073 // Find tracklet for TRD track <track>
2082 // Detailed description
2084 idx = track->GetTrackletIndex(p);
2085 AliTRDseedV1 *tracklet = (idx<0) ? NULL : (AliTRDseedV1*)fTracklets->UncheckedAt(idx);
2090 //____________________________________________________________________
2091 AliTRDseedV1* AliTRDtrackerV1::SetTracklet(const AliTRDseedV1 * const tracklet)
2093 // Add this tracklet to the list of tracklets stored in the tracker
2096 // - tracklet : pointer to the tracklet to be added to the list
2099 // - the index of the new tracklet in the tracker tracklets list
2101 // Detailed description
2102 // Build the tracklets list if it is not yet created (late initialization)
2103 // and adds the new tracklet to the list.
2106 fTracklets = new TClonesArray("AliTRDseedV1", AliTRDgeometry::Nsector()*kMaxTracksStack);
2107 fTracklets->SetOwner(kTRUE);
2109 Int_t nentries = fTracklets->GetEntriesFast();
2110 return new ((*fTracklets)[nentries]) AliTRDseedV1(*tracklet);
2113 //____________________________________________________________________
2114 AliTRDtrackV1* AliTRDtrackerV1::SetTrack(const AliTRDtrackV1 * const track)
2116 // Add this track to the list of tracks stored in the tracker
2119 // - track : pointer to the track to be added to the list
2122 // - the pointer added
2124 // Detailed description
2125 // Build the tracks list if it is not yet created (late initialization)
2126 // and adds the new track to the list.
2129 fTracks = new TClonesArray("AliTRDtrackV1", AliTRDgeometry::Nsector()*kMaxTracksStack);
2130 fTracks->SetOwner(kTRUE);
2132 Int_t nentries = fTracks->GetEntriesFast();
2133 return new ((*fTracks)[nentries]) AliTRDtrackV1(*track);
2138 //____________________________________________________________________
2139 Int_t AliTRDtrackerV1::Clusters2TracksSM(Int_t sector, AliESDEvent *esd)
2142 // Steer tracking for one SM.
2145 // sector : Array of (SM) propagation layers containing clusters
2146 // esd : The current ESD event. On output it contains the also
2147 // the ESD (TRD) tracks found in this SM.
2150 // Number of tracks found in this TRD supermodule.
2152 // Detailed description
2154 // 1. Unpack AliTRDpropagationLayers objects for each stack.
2155 // 2. Launch stack tracking.
2156 // See AliTRDtrackerV1::Clusters2TracksStack() for details.
2157 // 3. Pack results in the ESD event.
2161 Int_t nChambers = 0;
2162 AliTRDtrackingChamber **stack = NULL, *chamber = NULL;
2163 for(int istack = 0; istack<AliTRDgeometry::kNstack; istack++){
2164 if(!(stack = fTrSec[sector].GetStack(istack))) continue;
2166 for(int ilayer=0; ilayer<AliTRDgeometry::kNlayer; ilayer++){
2167 if(!(chamber = stack[ilayer])) continue;
2168 if(chamber->GetNClusters() < fgNTimeBins * fkRecoParam->GetFindableClusters()) continue;
2170 //AliInfo(Form("sector %d stack %d layer %d clusters %d", sector, istack, ilayer, chamber->GetNClusters()));
2172 if(nChambers < 4) continue;
2173 //AliInfo(Form("Doing stack %d", istack));
2174 nTracks += Clusters2TracksStack(stack, fTracksESD);
2176 if(nTracks) AliDebug(2, Form("Number of tracks: SM_%02d[%d]", sector, nTracks));
2178 for(int itrack=0; itrack<nTracks; itrack++){
2179 AliESDtrack *esdTrack((AliESDtrack*)(fTracksESD->operator[](itrack)));
2180 Int_t id = esd->AddTrack(esdTrack);
2182 // set ESD id to stand alone TRD tracks
2183 if (fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) > 0){
2184 esdTrack=esd->GetTrack(id);
2185 TObject *o(NULL); Int_t ic(0);
2186 AliTRDtrackV1 *calibTrack(NULL);
2187 while((o = esdTrack->GetCalibObject(ic++))){
2188 if(!(calibTrack = dynamic_cast<AliTRDtrackV1*>(o))) continue;
2189 calibTrack->SetESDid(esdTrack->GetID());
2195 // Reset Track and Candidate Number
2196 AliTRDtrackerDebug::SetCandidateNumber(0);
2197 AliTRDtrackerDebug::SetTrackNumber(0);
2199 // delete ESD tracks in the array
2200 fTracksESD->Delete();
2204 //____________________________________________________________________
2205 Int_t AliTRDtrackerV1::Clusters2TracksStack(AliTRDtrackingChamber **stack, TClonesArray * const esdTrackList)
2208 // Make tracks in one TRD stack.
2211 // layer : Array of stack propagation layers containing clusters
2212 // esdTrackList : Array of ESD tracks found by the stand alone tracker.
2213 // On exit the tracks found in this stack are appended.
2216 // Number of tracks found in this stack.
2218 // Detailed description
2220 // 1. Find the 3 most useful seeding chambers. See BuildSeedingConfigs() for details.
2221 // 2. Steer AliTRDtrackerV1::MakeSeeds() for 3 seeding layer configurations.
2222 // See AliTRDtrackerV1::MakeSeeds() for more details.
2223 // 3. Arrange track candidates in decreasing order of their quality
2224 // 4. Classify tracks in 5 categories according to:
2225 // a) number of layers crossed
2227 // 5. Sign clusters by tracks in decreasing order of track quality
2228 // 6. Build AliTRDtrack out of seeding tracklets
2230 // 8. Build ESD track and register it to the output list
2233 AliTRDtrackingChamber *chamber = NULL;
2234 AliTRDtrackingChamber **ci = NULL;
2235 AliTRDseedV1 sseed[kMaxTracksStack*6]; // to be initialized
2236 Int_t pars[4]; // MakeSeeds parameters
2238 //Double_t alpha = AliTRDgeometry::GetAlpha();
2239 //Double_t shift = .5 * alpha;
2240 Int_t configs[kNConfigs];
2242 // Purge used clusters from the containers
2244 for(Int_t ic = kNPlanes; ic--; ci++){
2245 if(!(*ci)) continue;
2249 // Build initial seeding configurations
2250 Double_t quality = BuildSeedingConfigs(stack, configs);
2251 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) > 10){
2252 AliInfo(Form("Plane config %d %d %d Quality %f"
2253 , configs[0], configs[1], configs[2], quality));
2257 // Initialize contors
2258 Int_t ntracks, // number of TRD track candidates
2259 ntracks1, // number of registered TRD tracks/iter
2260 ntracks2 = 0; // number of all registered TRD tracks in stack
2264 Int_t ic = 0; ci = &stack[0];
2265 while(ic<kNPlanes && !(*ci)){ic++; ci++;}
2266 if(!(*ci)) return ntracks2;
2267 Int_t istack = fGeom->GetStack((*ci)->GetDetector());
2270 // Loop over seeding configurations
2271 ntracks = 0; ntracks1 = 0;
2272 for (Int_t iconf = 0; iconf<3; iconf++) {
2273 pars[0] = configs[iconf];
2276 ntracks = MakeSeeds(stack, &sseed[6*ntracks], pars);
2277 //AliInfo(Form("Number of Tracks after iteration step %d: %d\n", iconf, ntracks));
2278 if(ntracks == kMaxTracksStack) break;
2280 AliDebug(2, Form("Candidate TRD tracks %d in iteration %d.", ntracks, fSieveSeeding));
2283 // Sort the seeds according to their quality
2284 Int_t sort[kMaxTracksStack];
2285 TMath::Sort(ntracks, fTrackQuality, sort, kTRUE);
2286 if(AliLog::GetDebugLevel("TRD", "AliTRDtrackerV1") > 2){
2287 AliDebug(3, "Track candidates classification:");
2288 for (Int_t it(0); it < ntracks; it++) {
2290 printf(" %2d idx[%d] Quality[%e]\n", it, jt, fTrackQuality[jt]);
2294 // Initialize number of tracks so far and logic switches
2295 Int_t ntracks0 = esdTrackList->GetEntriesFast();
2296 Bool_t signedTrack[kMaxTracksStack];
2297 Bool_t fakeTrack[kMaxTracksStack];
2298 for (Int_t i=0; i<ntracks; i++){
2299 signedTrack[i] = kFALSE;
2300 fakeTrack[i] = kFALSE;
2302 //AliInfo("Selecting track candidates ...");
2304 // Sieve clusters in decreasing order of track quality
2305 Int_t jSieve(0), rejectedCandidates(0);
2307 // Check track candidates
2308 rejectedCandidates=0;
2309 for (Int_t itrack = 0; itrack < ntracks; itrack++) {
2310 Int_t trackIndex = sort[itrack];
2311 if (signedTrack[trackIndex] || fakeTrack[trackIndex]) continue;
2313 // Calculate track parameters from tracklets seeds
2318 for (Int_t jLayer = 0; jLayer < kNPlanes; jLayer++) {
2319 Int_t jseed = kNPlanes*trackIndex+jLayer;
2320 sseed[jseed].UpdateUsed();
2321 if(!sseed[jseed].IsOK()) continue;
2322 // check if primary candidate
2323 if (TMath::Abs(sseed[jseed].GetYref(0) / sseed[jseed].GetX0()) < 0.158) findable++;
2324 ncl += sseed[jseed].GetN();
2325 nused += sseed[jseed].GetNUsed();
2329 // Filter duplicated tracks
2331 AliDebug(4, Form("REJECTED : %d idx[%d] quality[%e] tracklets[%d] usedClusters[%d]", itrack, trackIndex, fTrackQuality[trackIndex], nlayers, nused));
2332 fakeTrack[trackIndex] = kTRUE;
2335 if (ncl>0 && Float_t(nused)/ncl >= .25){
2336 AliDebug(4, Form("REJECTED : %d idx[%d] quality[%e] tracklets[%d] usedClusters[%d] used/ncl[%f]", itrack, trackIndex, fTrackQuality[trackIndex], nlayers, nused, Float_t(nused)/ncl));
2337 fakeTrack[trackIndex] = kTRUE;
2341 AliDebug(4, Form("Candidate[%d] Quality[%e] Tracklets[%d] Findable[%d] Ncl[%d] Nused[%d]", trackIndex, fTrackQuality[trackIndex], nlayers, findable, ncl, nused));
2344 Bool_t skip = kFALSE;
2346 case 0: // select 6 tracklets primary tracks, good quality
2347 if(nlayers > findable || nlayers < kNPlanes) {skip = kTRUE; break;}
2348 if(TMath::Log(1.E-9+fTrackQuality[trackIndex]) < -5.){skip = kTRUE; break;}
2351 case 1: // select shorter primary tracks, good quality
2352 if(findable<4){skip = kTRUE; break;}
2353 if(nlayers < findable){skip = kTRUE; break;}
2354 if(TMath::Log(1.E-9+fTrackQuality[trackIndex]) < -4.){skip = kTRUE; break;}
2357 case 2: // select 6 tracklets secondary tracks
2358 if(nlayers < kNPlanes) { skip = kTRUE; break;}
2359 if (TMath::Log(1.E-9+fTrackQuality[trackIndex]) < -6.0){skip = kTRUE; break;}
2362 case 3: // select shorter tracks, good quality
2363 if (nlayers<4){skip = kTRUE; break;}
2364 if (TMath::Log(1.E-9+fTrackQuality[trackIndex]) < -5.){skip = kTRUE; break;}
2367 case 4: // select anything with at least 4 tracklets
2368 if (nlayers<4){skip = kTRUE; break;}
2369 //if (TMath::Log(1.E-9+fTrackQuality[trackIndex]) - nused/(nlayers-3.0) < -15.0){skip = kTRUE; break;}
2373 rejectedCandidates++;
2374 AliDebug(4, Form("REJECTED : %d idx[%d] quality[%e] tracklets[%d] usedClusters[%d]", itrack, trackIndex, fTrackQuality[trackIndex], nlayers, nused));
2376 } else AliDebug(4, Form("ACCEPTED : %d idx[%d] quality[%e] tracklets[%d] usedClusters[%d]", itrack, trackIndex, fTrackQuality[trackIndex], nlayers, nused));
2378 signedTrack[trackIndex] = kTRUE;
2380 AliTRDseedV1 *lseed =&sseed[trackIndex*kNPlanes];
2381 AliTRDtrackV1 *track = MakeTrack(lseed);
2383 AliDebug(1, "Track building failed.");
2386 if(AliLog::GetDebugLevel("TRD", "AliTRDtrackerV1") > 1){
2387 Int_t ich = 0; while(!(chamber = stack[ich])) ich++;
2388 AliDebug(2, Form("Track pt=%7.2fGeV/c SM[%2d] Done.", track->Pt(), fGeom->GetSector(chamber->GetDetector())));
2392 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) > 1 && fkReconstructor->IsDebugStreaming()){
2393 //AliInfo(Form("Track %d [%d] nlayers %d trackQuality = %e nused %d, yref = %3.3f", itrack, trackIndex, nlayers, fTrackQuality[trackIndex], nused, trackParams[1]));
2395 AliTRDseedV1 *dseed[6];
2396 for(Int_t iseed = AliTRDgeometry::kNlayer; iseed--;) dseed[iseed] = new AliTRDseedV1(lseed[iseed]);
2398 //Int_t eventNrInFile = esd->GetEventNumberInFile();
2399 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
2400 Int_t trackNumber = AliTRDtrackerDebug::GetTrackNumber();
2401 Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
2402 TTreeSRedirector &cstreamer = *fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker);
2403 cstreamer << "Clusters2TracksStack"
2404 << "EventNumber=" << eventNumber
2405 << "TrackNumber=" << trackNumber
2406 << "CandidateNumber=" << candidateNumber
2407 << "Iter=" << fSieveSeeding
2408 << "Like=" << fTrackQuality[trackIndex]
2409 << "S0.=" << dseed[0]
2410 << "S1.=" << dseed[1]
2411 << "S2.=" << dseed[2]
2412 << "S3.=" << dseed[3]
2413 << "S4.=" << dseed[4]
2414 << "S5.=" << dseed[5]
2416 << "NLayers=" << nlayers
2417 << "Findable=" << findable
2418 << "NUsed=" << nused
2423 AliESDtrack *esdTrack = new ((*esdTrackList)[ntracks0++]) AliESDtrack();
2424 esdTrack->UpdateTrackParams(track, AliESDtrack::kTRDout);
2425 esdTrack->SetLabel(track->GetLabel());
2426 track->UpdateESDtrack(esdTrack);
2427 // write ESD-friends if neccessary
2428 if (fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) > 0){
2429 AliTRDtrackV1 *calibTrack = new AliTRDtrackV1(*track);
2430 calibTrack->SetOwner();
2431 esdTrack->AddCalibObject(calibTrack);
2434 AliTRDtrackerDebug::SetTrackNumber(AliTRDtrackerDebug::GetTrackNumber() + 1);
2438 } while(jSieve<5 && rejectedCandidates); // end track candidates sieve
2439 if(!ntracks1) break;
2441 // increment counters
2442 ntracks2 += ntracks1;
2444 if(fkReconstructor->IsHLT()) break;
2447 // Rebuild plane configurations and indices taking only unused clusters into account
2448 quality = BuildSeedingConfigs(stack, configs);
2449 if(quality < 1.E-7) break; //fkReconstructor->GetRecoParam() ->GetPlaneQualityThreshold()) break;
2451 for(Int_t ip = 0; ip < kNPlanes; ip++){
2452 if(!(chamber = stack[ip])) continue;
2453 chamber->Build(fGeom);//Indices(fSieveSeeding);
2456 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) > 10){
2457 AliInfo(Form("Sieve level %d Plane config %d %d %d Quality %f", fSieveSeeding, configs[0], configs[1], configs[2], quality));
2459 } while(fSieveSeeding<10); // end stack clusters sieve
2463 //AliInfo(Form("Registered TRD tracks %d in stack %d.", ntracks2, pars[1]));
2468 //___________________________________________________________________
2469 Double_t AliTRDtrackerV1::BuildSeedingConfigs(AliTRDtrackingChamber **stack, Int_t *configs)
2472 // Assign probabilities to chambers according to their
2473 // capability of producing seeds.
2477 // layers : Array of stack propagation layers for all 6 chambers in one stack
2478 // configs : On exit array of configuration indexes (see GetSeedingConfig()
2479 // for details) in the decreasing order of their seeding probabilities.
2483 // Return top configuration quality
2485 // Detailed description:
2487 // To each chamber seeding configuration (see GetSeedingConfig() for
2488 // the list of all configurations) one defines 2 quality factors:
2489 // - an apriori topological quality (see GetSeedingConfig() for details) and
2490 // - a data quality based on the uniformity of the distribution of
2491 // clusters over the x range (time bins population). See CookChamberQA() for details.
2492 // The overall chamber quality is given by the product of this 2 contributions.
2495 Double_t chamberQ[kNPlanes];memset(chamberQ, 0, kNPlanes*sizeof(Double_t));
2496 AliTRDtrackingChamber *chamber = NULL;
2497 for(int iplane=0; iplane<kNPlanes; iplane++){
2498 if(!(chamber = stack[iplane])) continue;
2499 chamberQ[iplane] = (chamber = stack[iplane]) ? chamber->GetQuality() : 0.;
2502 Double_t tconfig[kNConfigs];memset(tconfig, 0, kNConfigs*sizeof(Double_t));
2503 Int_t planes[] = {0, 0, 0, 0};
2504 for(int iconf=0; iconf<kNConfigs; iconf++){
2505 GetSeedingConfig(iconf, planes);
2506 tconfig[iconf] = fgTopologicQA[iconf];
2507 for(int iplane=0; iplane<4; iplane++) tconfig[iconf] *= chamberQ[planes[iplane]];
2510 TMath::Sort((Int_t)kNConfigs, tconfig, configs, kTRUE);
2511 // AliInfo(Form("q[%d] = %f", configs[0], tconfig[configs[0]]));
2512 // AliInfo(Form("q[%d] = %f", configs[1], tconfig[configs[1]]));
2513 // AliInfo(Form("q[%d] = %f", configs[2], tconfig[configs[2]]));
2515 return tconfig[configs[0]];
2518 //____________________________________________________________________
2519 Int_t AliTRDtrackerV1::MakeSeeds(AliTRDtrackingChamber **stack, AliTRDseedV1 * const sseed, const Int_t * const ipar)
2522 // Seed tracklets and build candidate TRD tracks. The procedure is used during barrel tracking to account for tracks which are
2523 // either missed by TPC prolongation or conversions inside the TRD volume.
2524 // For stand alone tracking the procedure is used to estimate all tracks measured by TRD.
2527 // layers : Array of stack propagation layers containing clusters
2528 // sseed : Array of empty tracklet seeds. On exit they are filled.
2529 // ipar : Control parameters:
2530 // ipar[0] -> seeding chambers configuration
2531 // ipar[1] -> stack index
2532 // ipar[2] -> number of track candidates found so far
2535 // Number of tracks candidates found.
2537 // The following steps are performed:
2538 // 1. Build seeding layers by collapsing all time bins from each of the four seeding chambers along the
2539 // radial coordinate. See AliTRDtrackingChamber::GetSeedingLayer() for details. The chambers selection for seeding
2540 // is described in AliTRDtrackerV1::Clusters2TracksStack().
2541 // 2. Using the seeding clusters from the seeding layer (step 1) build combinatorics using the following algorithm:
2542 // - for each seeding cluster in the lower seeding layer find
2543 // - all seeding clusters in the upper seeding layer inside a road defined by a given phi angle. The angle
2544 // is calculated on the minimum pt of tracks from vertex accesible to the stand alone tracker.
2545 // - for each pair of two extreme seeding clusters select middle upper cluster using roads defined externally by the
2547 // - select last seeding cluster as the nearest to the linear approximation of the track described by the first three
2548 // seeding clusters.
2549 // The implementation of road calculation and cluster selection can be found in the functions AliTRDchamberTimeBin::BuildCond()
2550 // and AliTRDchamberTimeBin::GetClusters().
2551 // 3. Helix fit of the seeding clusters set. (see AliTRDtrackerFitter::FitRieman(AliTRDcluster**)). No tilt correction is
2552 // performed at this level
2553 // 4. Initialize seeding tracklets in the seeding chambers.
2554 // 5. *Filter 0* Chi2 cut on the Y and Z directions. The threshold is set externally by the reco params.
2555 // 6. Attach (true) clusters to seeding tracklets (see AliTRDseedV1::AttachClusters()) and fit tracklet (see
2556 // AliTRDseedV1::Fit()). The number of used clusters used by current seeds should not exceed ... (25).
2557 // 7. *Filter 1* Check if all 4 seeding tracklets are correctly constructed.
2558 // 8. Helix fit of the clusters from the seeding tracklets with tilt correction. Refit tracklets using the new
2559 // approximation of the track.
2560 // 9. *Filter 2* Calculate likelihood of the track. (See AliTRDtrackerV1::CookLikelihood()). The following quantities are
2561 // checked against the Riemann fit:
2562 // - position resolution in y
2563 // - angular resolution in the bending plane
2564 // - likelihood of the number of clusters attached to the tracklet
2565 // 10. Extrapolation of the helix fit to the other 2 chambers *non seeding* chambers:
2566 // - Initialization of extrapolation tracklets with the fit parameters
2567 // - Attach clusters to extrapolated tracklets
2568 // - Helix fit of tracklets
2569 // 11. Improve seeding tracklets quality by reassigning clusters based on the last parameters of the track
2570 // See AliTRDtrackerV1::ImproveSeedQuality() for details.
2571 // 12. Helix fit of all 6 seeding tracklets and chi2 calculation
2572 // 13. Hyperplane fit and track quality calculation. See AliTRDtrackerFitter::FitHyperplane() for details.
2573 // 14. Cooking labels for tracklets. Should be done only for MC
2574 // 15. Register seeds.
2577 // Marian Ivanov <M.Ivanov@gsi.de>
2578 // Alexandru Bercuci <A.Bercuci@gsi.de>
2579 // Markus Fasel <M.Fasel@gsi.de>
2581 AliTRDtrackingChamber *chamber = NULL;
2582 AliTRDcluster *c[kNSeedPlanes] = {NULL, NULL, NULL, NULL}; // initilize seeding clusters
2583 AliTRDseedV1 *cseed = &sseed[0]; // initialize tracklets for first track
2584 Int_t ncl, mcl; // working variable for looping over clusters
2585 Int_t index[AliTRDchamberTimeBin::kMaxClustersLayer], jndex[AliTRDchamberTimeBin::kMaxClustersLayer];
2587 // chi2[0] = tracklet chi2 on the Z direction
2588 // chi2[1] = tracklet chi2 on the R direction
2591 // this should be data member of AliTRDtrack TODO
2592 Double_t seedQuality[kMaxTracksStack];
2594 // unpack control parameters
2595 Int_t config = ipar[0];
2596 Int_t ntracks = ipar[1];
2597 Int_t istack = ipar[2];
2598 Int_t planes[kNSeedPlanes]; GetSeedingConfig(config, planes);
2599 Int_t planesExt[kNPlanes-kNSeedPlanes]; GetExtrapolationConfig(config, planesExt);
2602 // Init chambers geometry
2603 Double_t hL[kNPlanes]; // Tilting angle
2604 Float_t padlength[kNPlanes]; // pad lenghts
2605 Float_t padwidth[kNPlanes]; // pad widths
2606 AliTRDpadPlane *pp = NULL;
2607 for(int iplane=0; iplane<kNPlanes; iplane++){
2608 pp = fGeom->GetPadPlane(iplane, istack);
2609 hL[iplane] = TMath::Tan(TMath::DegToRad()*pp->GetTiltingAngle());
2610 padlength[iplane] = pp->GetLengthIPad();
2611 padwidth[iplane] = pp->GetWidthIPad();
2614 // Init anode wire position for chambers
2615 Double_t x0[kNPlanes], // anode wire position
2616 driftLength = .5*AliTRDgeometry::AmThick() - AliTRDgeometry::DrThick(); // drift length
2617 TGeoHMatrix *matrix = NULL;
2618 Double_t loc[] = {AliTRDgeometry::AnodePos(), 0., 0.};
2619 Double_t glb[] = {0., 0., 0.};
2620 AliTRDtrackingChamber **cIter = &stack[0];
2621 for(int iLayer=0; iLayer<kNPlanes; iLayer++,cIter++){
2622 if(!(*cIter)) continue;
2623 if(!(matrix = fGeom->GetClusterMatrix((*cIter)->GetDetector()))){
2625 x0[iLayer] = fgkX0[iLayer];
2627 matrix->LocalToMaster(loc, glb);
2628 x0[iLayer] = glb[0];
2631 AliDebug(2, Form("Making seeds Stack[%d] Config[%d] Tracks[%d]...", istack, config, ntracks));
2633 // Build seeding layers
2636 for(int isl=0; isl<kNSeedPlanes; isl++){
2637 if(!(chamber = stack[planes[isl]])) continue;
2638 if(!chamber->GetSeedingLayer(fSeedTB[isl], fGeom, fkReconstructor)) continue;
2641 if(nlayers < kNSeedPlanes) return ntracks;
2644 // Start finding seeds
2645 Double_t cond0[4], cond1[4], cond2[4];
2647 while((c[3] = (*fSeedTB[3])[icl++])){
2649 fSeedTB[0]->BuildCond(c[3], cond0, 0);
2650 fSeedTB[0]->GetClusters(cond0, index, ncl);
2651 //printf("Found c[3] candidates 0 %d\n", ncl);
2654 c[0] = (*fSeedTB[0])[index[jcl++]];
2656 Double_t dx = c[3]->GetX() - c[0]->GetX();
2657 Double_t dzdx = (c[3]->GetZ() - c[0]->GetZ())/dx;
2658 Double_t dydx = (c[3]->GetY() - c[0]->GetY())/dx;
2659 fSeedTB[1]->BuildCond(c[0], cond1, 1, dzdx, dydx);
2660 fSeedTB[1]->GetClusters(cond1, jndex, mcl);
2661 //printf("Found c[0] candidates 1 %d\n", mcl);
2665 c[1] = (*fSeedTB[1])[jndex[kcl++]];
2667 fSeedTB[2]->BuildCond(c[1], cond2, 2, dzdx, dydx);
2668 c[2] = fSeedTB[2]->GetNearestCluster(cond2);
2669 //printf("Found c[1] candidate 2 %p\n", c[2]);
2672 AliDebug(3, Form("Seeding clusters\n 0[%6.3f %6.3f %6.3f]\n 1[%6.3f %6.3f %6.3f]\n 2[%6.3f %6.3f %6.3f]\n 3[%6.3f %6.3f %6.3f].",
2673 c[0]->GetX(), c[0]->GetY(), c[0]->GetZ(),
2674 c[1]->GetX(), c[1]->GetY(), c[1]->GetZ(),
2675 c[2]->GetX(), c[2]->GetY(), c[2]->GetZ(),
2676 c[3]->GetX(), c[3]->GetY(), c[3]->GetZ()));
2678 for (Int_t il = 0; il < kNPlanes; il++) cseed[il].Reset();
2682 AliTRDseedV1 *tseed = &cseed[0];
2684 for(int iLayer=0; iLayer<kNPlanes; iLayer++, tseed++, cIter++){
2685 Int_t det = (*cIter) ? (*cIter)->GetDetector() : -1;
2686 tseed->SetDetector(det);
2687 tseed->SetTilt(hL[iLayer]);
2688 tseed->SetPadLength(padlength[iLayer]);
2689 tseed->SetPadWidth(padwidth[iLayer]);
2690 tseed->SetReconstructor(fkReconstructor);
2691 tseed->SetX0(det<0 ? fR[iLayer]+driftLength : x0[iLayer]);
2692 tseed->Init(GetRiemanFitter());
2693 tseed->SetStandAlone(kTRUE);
2696 Bool_t isFake = kFALSE;
2697 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) >= 2 && fkReconstructor->IsDebugStreaming()){
2698 if (c[0]->GetLabel(0) != c[3]->GetLabel(0)) isFake = kTRUE;
2699 if (c[1]->GetLabel(0) != c[3]->GetLabel(0)) isFake = kTRUE;
2700 if (c[2]->GetLabel(0) != c[3]->GetLabel(0)) isFake = kTRUE;
2703 for(Int_t l = 0; l < kNSeedPlanes; l++) xpos[l] = fSeedTB[l]->GetX();
2705 for(int il=0; il<4; il++) yref[il] = cseed[planes[il]].GetYref(0);
2706 Int_t ll = c[3]->GetLabel(0);
2707 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
2708 Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
2709 AliRieman *rim = GetRiemanFitter();
2710 TTreeSRedirector &cs0 = *fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker);
2712 <<"EventNumber=" << eventNumber
2713 <<"CandidateNumber=" << candidateNumber
2714 <<"isFake=" << isFake
2715 <<"config=" << config
2717 <<"chi2z=" << chi2[0]
2718 <<"chi2y=" << chi2[1]
2719 <<"Y2exp=" << cond2[0]
2720 <<"Z2exp=" << cond2[1]
2721 <<"X0=" << xpos[0] //layer[sLayer]->GetX()
2722 <<"X1=" << xpos[1] //layer[sLayer + 1]->GetX()
2723 <<"X2=" << xpos[2] //layer[sLayer + 2]->GetX()
2724 <<"X3=" << xpos[3] //layer[sLayer + 3]->GetX()
2725 <<"yref0=" << yref[0]
2726 <<"yref1=" << yref[1]
2727 <<"yref2=" << yref[2]
2728 <<"yref3=" << yref[3]
2733 <<"Seed0.=" << &cseed[planes[0]]
2734 <<"Seed1.=" << &cseed[planes[1]]
2735 <<"Seed2.=" << &cseed[planes[2]]
2736 <<"Seed3.=" << &cseed[planes[3]]
2737 <<"RiemanFitter.=" << rim
2740 if(chi2[0] > fkRecoParam->GetChi2Z()/*7./(3. - sLayer)*//*iter*/){
2741 AliDebug(3, Form("Filter on chi2Z [%f].", chi2[0]));
2742 AliTRDtrackerDebug::SetCandidateNumber(AliTRDtrackerDebug::GetCandidateNumber() + 1);
2745 if(chi2[1] > fkRecoParam->GetChi2Y()/*1./(3. - sLayer)*//*iter*/){
2746 AliDebug(3, Form("Filter on chi2Y [%f].", chi2[1]));
2747 AliTRDtrackerDebug::SetCandidateNumber(AliTRDtrackerDebug::GetCandidateNumber() + 1);
2750 //AliInfo("Passed chi2 filter.");
2752 // try attaching clusters to tracklets
2754 AliTRDcluster *cl = NULL;
2755 for(int iLayer=0; iLayer<kNSeedPlanes; iLayer++){
2756 Int_t jLayer = planes[iLayer];
2757 Int_t nNotInChamber = 0;
2758 if(!cseed[jLayer].AttachClusters(stack[jLayer], kTRUE)) continue;
2759 if(/*fkReconstructor->IsHLT()*/kFALSE){
2760 cseed[jLayer].UpdateUsed();
2761 if(!cseed[jLayer].IsOK()) continue;
2763 cseed[jLayer].Fit();
2764 cseed[jLayer].UpdateUsed();
2765 cseed[jLayer].ResetClusterIter();
2766 while((cl = cseed[jLayer].NextCluster())){
2767 if(!cl->IsInChamber()) nNotInChamber++;
2769 //printf("clusters[%d], used[%d], not in chamber[%d]\n", cseed[jLayer].GetN(), cseed[jLayer].GetNUsed(), nNotInChamber);
2770 if(cseed[jLayer].GetN() - (cseed[jLayer].GetNUsed() + nNotInChamber) < 5) continue; // checking for Cluster which are not in chamber is a much stronger restriction on real data
2775 if(mlayers < kNSeedPlanes){
2776 AliDebug(2, Form("Found only %d tracklets out of %d. Skip.", mlayers, kNSeedPlanes));
2777 AliTRDtrackerDebug::SetCandidateNumber(AliTRDtrackerDebug::GetCandidateNumber() + 1);
2781 // temporary exit door for the HLT
2782 if(fkReconstructor->IsHLT()){
2783 // attach clusters to extrapolation chambers
2784 for(int iLayer=0; iLayer<kNPlanes-kNSeedPlanes; iLayer++){
2785 Int_t jLayer = planesExt[iLayer];
2786 if(!(chamber = stack[jLayer])) continue;
2787 if(!cseed[jLayer].AttachClusters(chamber, kTRUE)) continue;
2788 cseed[jLayer].Fit();
2790 FitTiltedRiemanConstraint(&cseed[0], GetZ());
2791 fTrackQuality[ntracks] = 1.; // dummy value
2793 if(ntracks == kMaxTracksStack) return ntracks;
2799 // Update Seeds and calculate Likelihood
2800 // fit tracklets and cook likelihood
2801 Double_t chi2Vals[4];
2802 chi2Vals[0] = FitTiltedRieman(&cseed[0], kTRUE);
2803 for(int iLayer=0; iLayer<kNSeedPlanes; iLayer++){
2804 Int_t jLayer = planes[iLayer];
2805 cseed[jLayer].Fit(kTRUE);
2807 Double_t like = CookLikelihood(&cseed[0], planes); // to be checked
2809 if (TMath::Log(1.E-9 + like) < fkRecoParam->GetTrackLikelihood()){
2810 AliDebug(3, Form("Filter on likelihood %f[%e].", TMath::Log(1.E-9 + like), like));
2811 AliTRDtrackerDebug::SetCandidateNumber(AliTRDtrackerDebug::GetCandidateNumber() + 1);
2814 //AliInfo(Form("Passed likelihood %f[%e].", TMath::Log(1.E-9 + like), like));
2816 // book preliminary results
2817 seedQuality[ntracks] = like;
2818 fSeedLayer[ntracks] = config;/*sLayer;*/
2820 // attach clusters to the extrapolation seeds
2822 for(int iLayer=0; iLayer<kNPlanes-kNSeedPlanes; iLayer++){
2823 Int_t jLayer = planesExt[iLayer];
2824 if(!(chamber = stack[jLayer])) continue;
2826 // fit extrapolated seed
2827 if ((jLayer == 0) && !(cseed[1].IsOK())) continue;
2828 if ((jLayer == 5) && !(cseed[4].IsOK())) continue;
2829 AliTRDseedV1 pseed = cseed[jLayer];
2830 if(!pseed.AttachClusters(chamber, kTRUE)) continue;
2832 cseed[jLayer] = pseed;
2833 chi2Vals[0] = FitTiltedRieman(cseed, kTRUE);
2834 cseed[jLayer].Fit(kTRUE);
2838 // AliInfo("Extrapolation done.");
2839 // Debug Stream containing all the 6 tracklets
2840 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) >= 2 && fkReconstructor->IsDebugStreaming()){
2841 TTreeSRedirector &cstreamer = *fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker);
2842 TLinearFitter *tiltedRieman = GetTiltedRiemanFitter();
2843 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
2844 Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
2845 cstreamer << "MakeSeeds1"
2846 << "EventNumber=" << eventNumber
2847 << "CandidateNumber=" << candidateNumber
2848 << "S0.=" << &cseed[0]
2849 << "S1.=" << &cseed[1]
2850 << "S2.=" << &cseed[2]
2851 << "S3.=" << &cseed[3]
2852 << "S4.=" << &cseed[4]
2853 << "S5.=" << &cseed[5]
2854 << "FitterT.=" << tiltedRieman
2858 if(fkRecoParam->HasImproveTracklets()){
2859 if(!ImproveSeedQuality(stack, cseed, chi2Vals[0])){
2860 AliTRDtrackerDebug::SetCandidateNumber(AliTRDtrackerDebug::GetCandidateNumber() + 1);
2861 AliDebug(3, "ImproveSeedQuality() failed.");
2865 // do track fitting with vertex constraint
2866 if(fkRecoParam->IsVertexConstrained()) chi2Vals[1] = FitTiltedRiemanConstraint(&cseed[0], GetZ());
2867 else chi2Vals[1] = -1.;
2868 chi2Vals[2] = GetChi2Z(&cseed[0]);
2869 chi2Vals[3] = GetChi2Phi(&cseed[0]);
2871 // calculate track quality
2872 fTrackQuality[ntracks] = CalculateTrackLikelihood(&chi2Vals[0]);
2874 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) >= 2 && fkReconstructor->IsDebugStreaming()){
2875 TTreeSRedirector &cstreamer = *fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker);
2876 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
2877 Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
2878 TLinearFitter *fitterTC = GetTiltedRiemanFitterConstraint();
2879 TLinearFitter *fitterT = GetTiltedRiemanFitter();
2881 for(Int_t iseed = 0; iseed < kNPlanes; iseed++){
2882 ncls += cseed[iseed].IsOK() ? cseed[iseed].GetN2() : 0;
2884 cstreamer << "MakeSeeds2"
2885 << "EventNumber=" << eventNumber
2886 << "CandidateNumber=" << candidateNumber
2887 << "Chi2TR=" << chi2Vals[0]
2888 << "Chi2TC=" << chi2Vals[1]
2889 << "Nlayers=" << mlayers
2890 << "NClusters=" << ncls
2892 << "S0.=" << &cseed[0]
2893 << "S1.=" << &cseed[1]
2894 << "S2.=" << &cseed[2]
2895 << "S3.=" << &cseed[3]
2896 << "S4.=" << &cseed[4]
2897 << "S5.=" << &cseed[5]
2898 << "FitterT.=" << fitterT
2899 << "FitterTC.=" << fitterTC
2902 if(AliLog::GetDebugLevel("TRD", "AliTRDtrackerV1")){
2903 Double_t pt[]={0., 0.};
2904 for(Int_t il(0); il<kNPlanes; il++){
2905 if(!cseed[il].IsOK()) continue;
2906 pt[0] = GetBz()*kB2C/cseed[il].GetC();
2907 pt[1] = GetBz()*kB2C/cseed[il].GetC(1);
2910 AliDebug(2, Form("Candidate[%2d] pt[%7.3f %7.3f] Q[%e]\n"
2911 " [0] x[%6.2f] n[%2d] nu[%d] OK[%c]\n"
2912 " [1] x[%6.2f] n[%2d] nu[%d] OK[%c]\n"
2913 " [2] x[%6.2f] n[%2d] nu[%d] OK[%c]\n"
2914 " [3] x[%6.2f] n[%2d] nu[%d] OK[%c]\n"
2915 " [4] x[%6.2f] n[%2d] nu[%d] OK[%c]\n"
2916 " [5] x[%6.2f] n[%2d] nu[%d] OK[%c]"
2917 , ntracks, pt[0], pt[1], fTrackQuality[ntracks]
2918 ,cseed[0].GetX(), cseed[0].GetN(), cseed[0].GetNUsed(), cseed[0].IsOK()?'y':'n'
2919 ,cseed[1].GetX(), cseed[1].GetN(), cseed[1].GetNUsed(), cseed[1].IsOK()?'y':'n'
2920 ,cseed[2].GetX(), cseed[2].GetN(), cseed[2].GetNUsed(), cseed[2].IsOK()?'y':'n'
2921 ,cseed[3].GetX(), cseed[3].GetN(), cseed[3].GetNUsed(), cseed[3].IsOK()?'y':'n'
2922 ,cseed[4].GetX(), cseed[4].GetN(), cseed[4].GetNUsed(), cseed[4].IsOK()?'y':'n'
2923 ,cseed[5].GetX(), cseed[5].GetN(), cseed[5].GetNUsed(), cseed[5].IsOK()?'y':'n'));
2926 AliTRDtrackerDebug::SetCandidateNumber(AliTRDtrackerDebug::GetCandidateNumber() + 1);
2927 if(ntracks == kMaxTracksStack){
2928 AliWarning(Form("Number of seeds reached maximum allowed (%d) in stack.", kMaxTracksStack));
2939 //_____________________________________________________________________________
2940 AliTRDtrackV1* AliTRDtrackerV1::MakeTrack(AliTRDseedV1 * const tracklet)
2943 // Build a TRD track out of tracklet candidates
2946 // seeds : array of tracklets
2947 // params : array of track parameters as they are estimated by stand alone tracker. 7 elements.
2948 // [0] - radial position of the track at reference point
2949 // [1] - y position of the fit at [0]
2950 // [2] - z position of the fit at [0]
2951 // [3] - snp of the first tracklet
2952 // [4] - tgl of the first tracklet
2953 // [5] - curvature of the Riemann fit - 1/pt
2954 // [6] - sector rotation angle
2959 // Initialize the TRD track based on the parameters of the fit and a parametric covariance matrix
2960 // (diagonal with constant variance terms TODO - correct parameterization)
2962 // In case of HLT just register the tracklets in the tracker and return values of the Riemann fit. For the
2963 // offline case perform a full Kalman filter on the already found tracklets (see AliTRDtrackerV1::FollowBackProlongation()
2964 // for details). Do also MC label calculation and PID if propagation successfully.
2967 Double_t alpha = AliTRDgeometry::GetAlpha();
2968 Double_t shift = AliTRDgeometry::GetAlpha()/2.0;
2970 // find first good tracklet
2971 Int_t idx(0); while(idx<kNPlanes && !tracklet[idx].IsOK()) idx++;
2972 if(idx>2){ AliDebug(1, Form("Found suspect track start @ layer idx[%d]\n"
2973 " %c[0] x0[%f] n[%d] nu[%d] OK[%c]\n"
2974 " %c[1] x0[%f] n[%d] nu[%d] OK[%c]\n"
2975 " %c[2] x0[%f] n[%d] nu[%d] OK[%c]\n"
2976 " %c[3] x0[%f] n[%d] nu[%d] OK[%c]\n"
2977 " %c[4] x0[%f] n[%d] nu[%d] OK[%c]\n"
2978 " %c[5] x0[%f] n[%d] nu[%d] OK[%c]"
2980 ,idx==0?'*':' ', tracklet[0].GetX0(), tracklet[0].GetN(), tracklet[0].GetNUsed(), tracklet[0].IsOK()?'y':'n'
2981 ,idx==1?'*':' ', tracklet[1].GetX0(), tracklet[1].GetN(), tracklet[1].GetNUsed(), tracklet[1].IsOK()?'y':'n'
2982 ,idx==2?'*':' ', tracklet[2].GetX0(), tracklet[2].GetN(), tracklet[2].GetNUsed(), tracklet[2].IsOK()?'y':'n'
2983 ,idx==3?'*':' ', tracklet[3].GetX0(), tracklet[3].GetN(), tracklet[3].GetNUsed(), tracklet[3].IsOK()?'y':'n'
2984 ,idx==4?'*':' ', tracklet[4].GetX0(), tracklet[4].GetN(), tracklet[4].GetNUsed(), tracklet[4].IsOK()?'y':'n'
2985 ,idx==5?'*':' ', tracklet[5].GetX0(), tracklet[5].GetN(), tracklet[5].GetNUsed(), tracklet[5].IsOK()?'y':'n'));
2990 Double_t x(tracklet[idx].GetX0() - dx);
2991 // Build track parameters
2992 Double_t params[] = {
2993 tracklet[idx].GetYref(0) - dx*tracklet[idx].GetYref(1) // y
2994 ,tracklet[idx].GetZref(0) - dx*tracklet[idx].GetZref(1) // z
2995 ,TMath::Sin(TMath::ATan(tracklet[idx].GetYref(1))) // snp
2996 ,tracklet[idx].GetZref(1) / TMath::Sqrt(1. + tracklet[idx].GetYref(1) * tracklet[idx].GetYref(1)) // tgl
2997 ,tracklet[idx].GetC(fkReconstructor->IsHLT()?1:0) // curvature -> 1/pt
2999 Int_t sector(fGeom->GetSector(tracklet[idx].GetDetector()));
3002 c[ 0] = 0.2; // s^2_y
3003 c[ 1] = 0.0; c[ 2] = 2.0; // s^2_z
3004 c[ 3] = 0.0; c[ 4] = 0.0; c[ 5] = 0.02; // s^2_snp
3005 c[ 6] = 0.0; c[ 7] = 0.0; c[ 8] = 0.0; c[ 9] = 0.1; // s^2_tgl
3006 c[10] = 0.0; c[11] = 0.0; c[12] = 0.0; c[13] = 0.0; c[14] = params[4]*params[4]*0.01; // s^2_1/pt
3008 AliTRDtrackV1 track(tracklet, params, c, x, sector*alpha+shift);
3010 AliTRDseedV1 *ptrTracklet = NULL;
3012 // skip Kalman filter for HLT
3013 if(/*fkReconstructor->IsHLT()*/kFALSE){
3014 for (Int_t jLayer = 0; jLayer < AliTRDgeometry::kNlayer; jLayer++) {
3015 track.UnsetTracklet(jLayer);
3016 ptrTracklet = &tracklet[jLayer];
3017 if(!ptrTracklet->IsOK()) continue;
3018 if(TMath::Abs(ptrTracklet->GetYref(1) - ptrTracklet->GetYfit(1)) >= .2) continue; // check this condition with Marian
3019 ptrTracklet = SetTracklet(ptrTracklet);
3020 ptrTracklet->UseClusters();
3021 track.SetTracklet(ptrTracklet, fTracklets->GetEntriesFast()-1);
3023 AliTRDtrackV1 *ptrTrack = SetTrack(&track);
3024 ptrTrack->CookPID();
3025 ptrTrack->CookLabel(.9);
3026 ptrTrack->SetReconstructor(fkReconstructor);
3030 // prevent the error message in AliTracker::MeanMaterialBudget: "start point out of geometry"
3031 if(TMath::Abs(track.GetX()) + TMath::Abs(track.GetY()) + TMath::Abs(track.GetZ()) > 10000) return NULL;
3033 track.ResetCovariance(1);
3034 Int_t nc = TMath::Abs(FollowBackProlongation(track));
3035 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) > 5 && fkReconstructor->IsDebugStreaming()){
3036 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
3037 Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
3038 Double_t p[5]; // Track Params for the Debug Stream
3039 track.GetExternalParameters(x, p);
3040 TTreeSRedirector &cs = *fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker);
3042 << "EventNumber=" << eventNumber
3043 << "CandidateNumber=" << candidateNumber
3051 << "Yin=" << params[0]
3052 << "Zin=" << params[1]
3053 << "snpin=" << params[2]
3054 << "tndin=" << params[3]
3055 << "crvin=" << params[4]
3056 << "track.=" << &track
3060 UnsetTrackletsTrack(&track);
3063 AliTRDtrackV1 *ptrTrack = SetTrack(&track);
3064 ptrTrack->SetReconstructor(fkReconstructor);
3065 ptrTrack->CookLabel(.9);
3066 for(Int_t il(kNPlanes); il--;){
3067 if(!(ptrTracklet = ptrTrack->GetTracklet(il))) continue;
3068 ptrTracklet->UseClusters();
3071 // computes PID for track
3072 ptrTrack->CookPID();
3073 // update calibration references using this track
3074 AliTRDCalibraFillHisto *calibra = AliTRDCalibraFillHisto::Instance();
3076 AliInfo("Could not get Calibra instance\n");
3077 if(calibra->GetHisto2d()) calibra->UpdateHistogramsV1(ptrTrack);
3083 //____________________________________________________________________
3084 Bool_t AliTRDtrackerV1::ImproveSeedQuality(AliTRDtrackingChamber **stack, AliTRDseedV1 *cseed, Double_t &chi2)
3087 // Sort tracklets according to "quality" and try to "improve" the first 4 worst
3090 // layers : Array of propagation layers for a stack/supermodule
3091 // cseed : Array of 6 seeding tracklets which has to be improved
3094 // cssed : Improved seeds
3096 // Detailed description
3098 // Iterative procedure in which new clusters are searched for each
3099 // tracklet seed such that the seed quality (see AliTRDseed::GetQuality())
3100 // can be maximized. If some optimization is found the old seeds are replaced.
3105 // make a local working copy
3106 AliTRDtrackingChamber *chamber = NULL;
3107 AliTRDseedV1 bseed[AliTRDgeometry::kNlayer];
3109 Float_t quality(1.e3),
3110 lQuality[] = {1.e3, 1.e3, 1.e3, 1.e3, 1.e3, 1.e3};
3112 for(Int_t jLayer=AliTRDgeometry::kNlayer; jLayer--;){
3113 bseed[jLayer] = cseed[jLayer];
3114 if(!bseed[jLayer].IsOK()) continue;
3116 lQuality[jLayer] = bseed[jLayer].GetQuality(kTRUE);
3117 quality += lQuality[jLayer];
3120 AliDebug(2, Form("Start N[%d] Q[%f] chi2[%f]", rLayers, quality, chi2));
3122 for (Int_t iter = 0; iter < 4; iter++) {
3123 // Try better cluster set
3124 Int_t nLayers(0); Float_t qualitynew(0.);
3126 TMath::Sort(Int_t(AliTRDgeometry::kNlayer), lQuality, indexes, kFALSE);
3127 for(Int_t jLayer=AliTRDgeometry::kNlayer; jLayer--;) {
3128 Int_t bLayer = indexes[jLayer];
3129 bseed[bLayer].Reset("c");
3130 if(!(chamber = stack[bLayer])) continue;
3131 if(!bseed[bLayer].AttachClusters(chamber, kTRUE)) continue;
3132 bseed[bLayer].Fit(kTRUE);
3133 if(!bseed[bLayer].IsOK()) continue;
3135 lQuality[jLayer] = bseed[jLayer].GetQuality(kTRUE);
3136 qualitynew += lQuality[jLayer];
3138 if(rLayers > nLayers){
3139 AliDebug(1, Form("Lost %d tracklets while improving.", rLayers-nLayers));
3140 return iter>0?kTRUE:kFALSE;
3141 } else rLayers=nLayers;
3142 qualitynew /= rLayers;
3144 if(qualitynew > quality){
3145 AliDebug(4, Form("Quality[%f] worsen in iter[%d] to ref[%f].", qualitynew, iter, quality));
3146 return iter>0?kTRUE:kFALSE;
3147 } else quality = qualitynew;
3149 // try improve track parameters
3150 Float_t chi2new = FitTiltedRieman(bseed, kTRUE);
3152 AliDebug(4, Form("Chi2[%f] worsen in iter[%d] to ref[%f].", chi2new, iter, chi2));
3153 return iter>0?kTRUE:kFALSE;
3154 } else chi2 = chi2new;
3156 // store better tracklets
3157 for(Int_t jLayer=AliTRDgeometry::kNlayer; jLayer--;) cseed[jLayer]=bseed[jLayer];
3158 AliDebug(2, Form("Iter[%d] Q[%f] chi2[%f]", iter, quality, chi2));
3161 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) >= 7 && fkReconstructor->IsDebugStreaming()){
3162 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
3163 Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
3164 TLinearFitter *tiltedRieman = GetTiltedRiemanFitter();
3165 TTreeSRedirector &cstreamer = *fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker);
3166 cstreamer << "ImproveSeedQuality"
3167 << "EventNumber=" << eventNumber
3168 << "CandidateNumber=" << candidateNumber
3169 << "Iteration=" << iter
3170 << "S0.=" << &cseed[0]
3171 << "S1.=" << &cseed[1]
3172 << "S2.=" << &cseed[2]
3173 << "S3.=" << &cseed[3]
3174 << "S4.=" << &cseed[4]
3175 << "S5.=" << &cseed[5]
3176 << "FitterT.=" << tiltedRieman
3181 // we are sure that at least 4 tracklets are OK !
3185 //_________________________________________________________________________
3186 Double_t AliTRDtrackerV1::CalculateTrackLikelihood(Double_t *chi2){
3188 // Calculates the Track Likelihood value. This parameter serves as main quality criterion for
3189 // the track selection
3190 // The likelihood value containes:
3191 // - The chi2 values from the both fitters and the chi2 values in z-direction from a linear fit
3192 // - The Sum of the Parameter |slope_ref - slope_fit|/Sigma of the tracklets
3193 // For all Parameters an exponential dependency is used
3195 // Parameters: - Array of tracklets (AliTRDseedV1) related to the track candidate
3196 // - Array of chi2 values:
3197 // * Non-Constrained Tilted Riemann fit
3198 // * Vertex-Constrained Tilted Riemann fit
3199 // * z-Direction from Linear fit
3200 // Output: - The calculated track likelihood
3205 // Non-constrained Tilted Riemann
3206 Double_t likeChi2TR = TMath::Exp(-chi2[0] * 0.0078);
3207 // Constrained Tilted Riemann
3208 Double_t likeChi2TC(1.);
3210 likeChi2TC = TMath::Exp(-chi2[1] * 0.677);
3211 Double_t r = likeChi2TC/likeChi2TR;
3212 if(r>1.e2){;} // -> a primary track use TC
3213 else if(r<1.e2) // -> a secondary track use TR
3215 else{;} // -> test not conclusive
3217 // Chi2 only on Z direction
3218 Double_t likeChi2Z = TMath::Exp(-chi2[2] * 0.14);
3219 // Chi2 angular resolution
3220 Double_t likeChi2Phi= TMath::Exp(-chi2[3] * 3.23);
3222 Double_t trackLikelihood = likeChi2Z * likeChi2TR * likeChi2TC * likeChi2Phi;
3224 AliDebug(2, Form("Likelihood [%e]\n"
3225 " Rieman : chi2[%f] likelihood[%6.2e]\n"
3226 " Vertex : chi2[%f] likelihood[%6.2e]\n"
3227 " Z : chi2[%f] likelihood[%6.2e]\n"
3228 " Phi : chi2[%f] likelihood[%6.2e]"
3230 , chi2[0], likeChi2TR
3231 , chi2[1], likeChi2TC
3232 , chi2[2], likeChi2Z
3233 , chi2[3], likeChi2Phi
3236 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) >= 2 && fkReconstructor->IsDebugStreaming()){
3237 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
3238 Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
3239 TTreeSRedirector &cstreamer = *fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker);
3240 cstreamer << "CalculateTrackLikelihood0"
3241 << "EventNumber=" << eventNumber
3242 << "CandidateNumber=" << candidateNumber
3243 << "LikeChi2Z=" << likeChi2Z
3244 << "LikeChi2TR=" << likeChi2TR
3245 << "LikeChi2TC=" << likeChi2TC
3246 << "LikeChi2Phi=" << likeChi2Phi
3247 << "TrackLikelihood=" << trackLikelihood
3251 return trackLikelihood;
3254 //____________________________________________________________________
3255 Double_t AliTRDtrackerV1::CookLikelihood(AliTRDseedV1 *cseed, Int_t planes[4])
3258 // Calculate the probability of this track candidate.
3261 // cseeds : array of candidate tracklets
3262 // planes : array of seeding planes (see seeding configuration)
3263 // chi2 : chi2 values (on the Z and Y direction) from the rieman fit of the track.
3268 // Detailed description
3270 // The track quality is estimated based on the following 4 criteria:
3271 // 1. precision of the rieman fit on the Y direction (likea)
3272 // 2. chi2 on the Y direction (likechi2y)
3273 // 3. chi2 on the Z direction (likechi2z)
3274 // 4. number of attached clusters compared to a reference value
3275 // (see AliTRDrecoParam::fkFindable) (likeN)
3277 // The distributions for each type of probabilities are given below as of
3278 // (date). They have to be checked to assure consistency of estimation.
3281 // ratio of the total number of clusters/track which are expected to be found by the tracker.
3282 Double_t chi2y = GetChi2Y(&cseed[0]);
3283 Double_t chi2z = GetChi2Z(&cseed[0]);
3285 Float_t nclusters = 0.;
3286 Double_t sumda = 0.;
3287 for(UChar_t ilayer = 0; ilayer < 4; ilayer++){
3288 Int_t jlayer = planes[ilayer];
3289 nclusters += cseed[jlayer].GetN2();
3290 sumda += TMath::Abs(cseed[jlayer].GetYfit(1) - cseed[jlayer].GetYref(1));
3294 Double_t likea = TMath::Exp(-sumda * fkRecoParam->GetPhiSlope());
3295 Double_t likechi2y = 0.0000000001;
3296 if (fkReconstructor->IsCosmic() || chi2y < fkRecoParam->GetChi2YCut()) likechi2y += TMath::Exp(-TMath::Sqrt(chi2y) * fkRecoParam->GetChi2YSlope());
3297 Double_t likechi2z = TMath::Exp(-chi2z * fkRecoParam->GetChi2ZSlope());
3298 Double_t likeN = TMath::Exp(-(fkRecoParam->GetNMeanClusters() - nclusters) / fkRecoParam->GetNSigmaClusters());
3299 Double_t like = likea * likechi2y * likechi2z * likeN;
3301 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) >= 2 && fkReconstructor->IsDebugStreaming()){
3302 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
3303 Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
3304 Int_t nTracklets = 0; Float_t meanNcls = 0;
3305 for(Int_t iseed=0; iseed < kNPlanes; iseed++){
3306 if(!cseed[iseed].IsOK()) continue;
3308 meanNcls += cseed[iseed].GetN2();
3310 if(nTracklets) meanNcls /= nTracklets;
3311 // The Debug Stream contains the seed
3312 TTreeSRedirector &cstreamer = *fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker);
3313 cstreamer << "CookLikelihood"
3314 << "EventNumber=" << eventNumber
3315 << "CandidateNumber=" << candidateNumber
3316 << "tracklet0.=" << &cseed[0]
3317 << "tracklet1.=" << &cseed[1]
3318 << "tracklet2.=" << &cseed[2]
3319 << "tracklet3.=" << &cseed[3]
3320 << "tracklet4.=" << &cseed[4]
3321 << "tracklet5.=" << &cseed[5]
3322 << "sumda=" << sumda
3323 << "chi2y=" << chi2y
3324 << "chi2z=" << chi2z
3325 << "likea=" << likea
3326 << "likechi2y=" << likechi2y
3327 << "likechi2z=" << likechi2z
3328 << "nclusters=" << nclusters
3329 << "likeN=" << likeN
3331 << "meanncls=" << meanNcls
3338 //____________________________________________________________________
3339 void AliTRDtrackerV1::GetSeedingConfig(Int_t iconfig, Int_t planes[4])
3342 // Map seeding configurations to detector planes.
3345 // iconfig : configuration index
3346 // planes : member planes of this configuration. On input empty.
3349 // planes : contains the planes which are defining the configuration
3351 // Detailed description
3353 // Here is the list of seeding planes configurations together with
3354 // their topological classification:
3372 // The topologic quality is modeled as follows:
3373 // 1. The general model is define by the equation:
3374 // p(conf) = exp(-conf/2)
3375 // 2. According to the topologic classification, configurations from the same
3376 // class are assigned the agerage value over the model values.
3377 // 3. Quality values are normalized.
3379 // The topologic quality distribution as function of configuration is given below:
3381 // <img src="gif/topologicQA.gif">
3386 case 0: // 5432 TQ 0
3392 case 1: // 4321 TQ 0
3398 case 2: // 3210 TQ 0
3404 case 3: // 5321 TQ 1
3410 case 4: // 4210 TQ 1
3416 case 5: // 5431 TQ 1
3422 case 6: // 4320 TQ 1
3428 case 7: // 5430 TQ 2
3434 case 8: // 5210 TQ 2
3440 case 9: // 5421 TQ 3
3446 case 10: // 4310 TQ 3
3452 case 11: // 5410 TQ 4
3458 case 12: // 5420 TQ 5
3464 case 13: // 5320 TQ 5
3470 case 14: // 5310 TQ 5
3479 //____________________________________________________________________
3480 void AliTRDtrackerV1::GetExtrapolationConfig(Int_t iconfig, Int_t planes[2])
3483 // Returns the extrapolation planes for a seeding configuration.
3486 // iconfig : configuration index
3487 // planes : planes which are not in this configuration. On input empty.
3490 // planes : contains the planes which are not in the configuration
3492 // Detailed description
3496 case 0: // 5432 TQ 0
3500 case 1: // 4321 TQ 0
3504 case 2: // 3210 TQ 0
3508 case 3: // 5321 TQ 1
3512 case 4: // 4210 TQ 1
3516 case 5: // 5431 TQ 1
3520 case 6: // 4320 TQ 1
3524 case 7: // 5430 TQ 2
3528 case 8: // 5210 TQ 2
3532 case 9: // 5421 TQ 3
3536 case 10: // 4310 TQ 3
3540 case 11: // 5410 TQ 4
3544 case 12: // 5420 TQ 5
3548 case 13: // 5320 TQ 5
3552 case 14: // 5310 TQ 5
3559 //____________________________________________________________________
3560 AliCluster* AliTRDtrackerV1::GetCluster(Int_t idx) const
3562 if(!fClusters) return NULL;
3563 Int_t ncls = fClusters->GetEntriesFast();
3564 return idx >= 0 && idx < ncls ? (AliCluster*)fClusters->UncheckedAt(idx) : NULL;
3567 //____________________________________________________________________
3568 AliTRDseedV1* AliTRDtrackerV1::GetTracklet(Int_t idx) const
3570 if(!fTracklets) return NULL;
3571 Int_t ntrklt = fTracklets->GetEntriesFast();
3572 return idx >= 0 && idx < ntrklt ? (AliTRDseedV1*)fTracklets->UncheckedAt(idx) : NULL;
3575 //____________________________________________________________________
3576 AliKalmanTrack* AliTRDtrackerV1::GetTrack(Int_t idx) const
3578 if(!fTracks) return NULL;
3579 Int_t ntrk = fTracks->GetEntriesFast();
3580 return idx >= 0 && idx < ntrk ? (AliKalmanTrack*)fTracks->UncheckedAt(idx) : NULL;
3585 // //_____________________________________________________________________________
3586 // Int_t AliTRDtrackerV1::Freq(Int_t n, const Int_t *inlist
3587 // , Int_t *outlist, Bool_t down)
3590 // // Sort eleements according occurancy
3591 // // The size of output array has is 2*n
3598 // Int_t *sindexS = new Int_t[n]; // Temporary array for sorting
3599 // Int_t *sindexF = new Int_t[2*n];
3600 // for (Int_t i = 0; i < n; i++) {
3604 // TMath::Sort(n,inlist,sindexS,down);
3606 // Int_t last = inlist[sindexS[0]];
3607 // Int_t val = last;
3609 // sindexF[0+n] = last;
3610 // Int_t countPos = 0;
3612 // // Find frequency
3613 // for (Int_t i = 1; i < n; i++) {
3614 // val = inlist[sindexS[i]];
3615 // if (last == val) {
3616 // sindexF[countPos]++;
3620 // sindexF[countPos+n] = val;
3621 // sindexF[countPos]++;
3625 // if (last == val) {
3629 // // Sort according frequency
3630 // TMath::Sort(countPos,sindexF,sindexS,kTRUE);
3632 // for (Int_t i = 0; i < countPos; i++) {
3633 // outlist[2*i ] = sindexF[sindexS[i]+n];
3634 // outlist[2*i+1] = sindexF[sindexS[i]];
3637 // delete [] sindexS;
3638 // delete [] sindexF;
3645 //____________________________________________________________________
3646 void AliTRDtrackerV1::ResetSeedTB()
3648 // reset buffer for seeding time bin layers. If the time bin
3649 // layers are not allocated this function allocates them
3651 for(Int_t isl=0; isl<kNSeedPlanes; isl++){
3652 if(!fSeedTB[isl]) fSeedTB[isl] = new AliTRDchamberTimeBin();
3653 else fSeedTB[isl]->Clear();
3658 //_____________________________________________________________________________
3659 Float_t AliTRDtrackerV1::GetChi2Y(const AliTRDseedV1 * const tracklets) const
3661 // Calculates normalized chi2 in y-direction
3662 // chi2 = Sum chi2 / n_tracklets
3664 Double_t chi2 = 0.; Int_t n = 0;
3665 for(Int_t ipl = kNPlanes; ipl--;){
3666 if(!tracklets[ipl].IsOK()) continue;
3667 chi2 += tracklets[ipl].GetChi2Y();
3670 return n ? chi2/n : 0.;
3673 //_____________________________________________________________________________
3674 Float_t AliTRDtrackerV1::GetChi2Z(const AliTRDseedV1 *const tracklets) const
3676 // Calculates normalized chi2 in z-direction
3677 // chi2 = Sum chi2 / n_tracklets
3679 Double_t chi2 = 0; Int_t n = 0;
3680 for(Int_t ipl = kNPlanes; ipl--;){
3681 if(!tracklets[ipl].IsOK()) continue;
3682 chi2 += tracklets[ipl].GetChi2Z();
3685 return n ? chi2/n : 0.;
3688 //_____________________________________________________________________________
3689 Float_t AliTRDtrackerV1::GetChi2Phi(const AliTRDseedV1 *const tracklets) const
3691 // Calculates normalized chi2 for angular resolution
3692 // chi2 = Sum chi2 / n_tracklets
3694 Double_t chi2 = 0; Int_t n = 0;
3695 for (Int_t iLayer = 0; iLayer < kNPlanes; iLayer++) {
3696 if(!tracklets[iLayer].IsOK()) continue;
3697 chi2 += tracklets[iLayer].GetChi2Phi();
3700 return n ? chi2/n: 0.;
3703 //____________________________________________________________________
3704 Float_t AliTRDtrackerV1::CalculateReferenceX(const AliTRDseedV1 *const tracklets){
3706 // Calculates the reference x-position for the tilted Rieman fit defined as middle
3707 // of the stack (middle between layers 2 and 3). For the calculation all the tracklets
3708 // are taken into account
3710 // Parameters: - Array of tracklets(AliTRDseedV1)
3712 // Output: - The reference x-position(Float_t)
3713 // Only kept for compatibility with the old code
3715 Int_t nDistances = 0;
3716 Float_t meanDistance = 0.;
3717 Int_t startIndex = 5;
3718 for(Int_t il =5; il > 0; il--){
3719 if(tracklets[il].IsOK() && tracklets[il -1].IsOK()){
3720 Float_t xdiff = tracklets[il].GetX0() - tracklets[il -1].GetX0();
3721 meanDistance += xdiff;
3724 if(tracklets[il].IsOK()) startIndex = il;
3726 if(tracklets[0].IsOK()) startIndex = 0;
3728 // We should normally never get here
3729 Float_t xpos[2]; memset(xpos, 0, sizeof(Float_t) * 2);
3730 Int_t iok = 0, idiff = 0;
3731 // This attempt is worse and should be avoided:
3732 // check for two chambers which are OK and repeat this without taking the mean value
3733 // Strategy avoids a division by 0;
3734 for(Int_t il = 5; il >= 0; il--){
3735 if(tracklets[il].IsOK()){
3736 xpos[iok] = tracklets[il].GetX0();
3740 if(iok) idiff++; // to get the right difference;
3744 meanDistance = (xpos[0] - xpos[1])/idiff;
3747 // we have do not even have 2 layers which are OK? The we do not need to fit at all
3752 meanDistance /= nDistances;
3754 return tracklets[startIndex].GetX0() + (2.5 - startIndex) * meanDistance - 0.5 * (AliTRDgeometry::AmThick() + AliTRDgeometry::DrThick());
3757 //_____________________________________________________________________________
3758 Double_t AliTRDtrackerV1::FitTiltedRiemanV1(AliTRDseedV1 *const tracklets){
3760 // Track Fitter Function using the new class implementation of
3763 AliTRDtrackFitterRieman fitter;
3764 fitter.SetRiemanFitter(GetTiltedRiemanFitter());
3766 for(Int_t il = 0; il < AliTRDgeometry::kNlayer; il++) fitter.SetTracklet(il, &tracklets[il]);
3767 Double_t chi2 = fitter.Eval();
3768 // Update the tracklets
3769 Double_t cov[15]; Double_t x0;
3770 memset(cov, 0, sizeof(Double_t) * 15);
3771 for(Int_t il = 0; il < AliTRDgeometry::kNlayer; il++){
3772 x0 = tracklets[il].GetX0();
3773 tracklets[il].SetYref(0, fitter.GetYat(x0));
3774 tracklets[il].SetZref(0, fitter.GetZat(x0));
3775 tracklets[il].SetYref(1, fitter.GetDyDxAt(x0));
3776 tracklets[il].SetZref(1, fitter.GetDzDx());
3777 tracklets[il].SetC(fitter.GetCurvature());
3778 fitter.GetCovAt(x0, cov);
3779 tracklets[il].SetCovRef(cov);
3780 tracklets[il].SetChi2(chi2);
3785 //____________________________________________________________________
3786 void AliTRDtrackerV1::UnsetTrackletsTrack(const AliTRDtrackV1 * const track)
3789 for(Int_t il(0); il<kNPlanes; il++){
3790 if((idx = track->GetTrackletIndex(il)) < 0) continue;
3791 delete (fTracklets->RemoveAt(idx));
3796 ///////////////////////////////////////////////////////
3798 // Resources of class AliTRDLeastSquare //
3800 ///////////////////////////////////////////////////////
3802 //_____________________________________________________________________________
3803 AliTRDtrackerV1::AliTRDLeastSquare::AliTRDLeastSquare(){
3805 // Constructor of the nested class AliTRDtrackFitterLeastSquare
3807 // Fast solving linear regresion in 2D
3809 // The data members have the following meaning
3820 // fCovarianceMatrix[0] : s2a
3821 // fCovarianceMatrix[1] : s2b
3822 // fCovarianceMatrix[2] : cov(ab)
3824 memset(fParams, 0, sizeof(Double_t) * 2);
3825 memset(fSums, 0, sizeof(Double_t) * 6);
3826 memset(fCovarianceMatrix, 0, sizeof(Double_t) * 3);
3830 //_____________________________________________________________________________
3831 void AliTRDtrackerV1::AliTRDLeastSquare::AddPoint(const Double_t *const x, Double_t y, Double_t sigmaY){
3833 // Adding Point to the fitter
3836 Double_t weight = 1/(sigmaY > 1e-9 ? sigmaY : 1e-9);
3838 const Double_t &xpt = *x;
3839 // printf("Adding point x = %f, y = %f, sigma = %f\n", xpt, y, sigmaY);
3841 fSums[1] += weight * xpt;
3842 fSums[2] += weight * y;
3843 fSums[3] += weight * xpt * y;
3844 fSums[4] += weight * xpt * xpt;
3845 fSums[5] += weight * y * y;
3848 //_____________________________________________________________________________
3849 void AliTRDtrackerV1::AliTRDLeastSquare::RemovePoint(const Double_t *const x, Double_t y, Double_t sigmaY){
3851 // Remove Point from the sample
3854 Double_t weight = 1/(sigmaY > 1e-9 ? sigmaY : 1e-9);
3856 const Double_t &xpt = *x;
3858 fSums[1] -= weight * xpt;
3859 fSums[2] -= weight * y;
3860 fSums[3] -= weight * xpt * y;
3861 fSums[4] -= weight * xpt * xpt;
3862 fSums[5] -= weight * y * y;
3865 //_____________________________________________________________________________
3866 Bool_t AliTRDtrackerV1::AliTRDLeastSquare::Eval(){
3868 // Evaluation of the fit:
3869 // Calculation of the parameters
3870 // Calculation of the covariance matrix
3873 Double_t det = fSums[0] * fSums[4] - fSums[1] *fSums[1];
3874 if(det==0) return kFALSE;
3876 // for(Int_t isum = 0; isum < 5; isum++)
3877 // printf("fSums[%d] = %f\n", isum, fSums[isum]);
3878 // printf("denominator = %f\n", denominator);
3879 fParams[0] = (fSums[2] * fSums[4] - fSums[1] * fSums[3])/det;
3880 fParams[1] = (fSums[0] * fSums[3] - fSums[1] * fSums[2])/det;
3881 // printf("fParams[0] = %f, fParams[1] = %f\n", fParams[0], fParams[1]);
3883 // Covariance matrix
3884 Double_t den = fSums[0]*fSums[4] - fSums[1]*fSums[1];
3885 fCovarianceMatrix[0] = fSums[4] / den;
3886 fCovarianceMatrix[1] = fSums[0] / den;
3887 fCovarianceMatrix[2] = -fSums[1] / den;
3888 /* fCovarianceMatrix[0] = fSums[4] / fSums[0] - fSums[1] * fSums[1] / (fSums[0] * fSums[0]);
3889 fCovarianceMatrix[1] = fSums[5] / fSums[0] - fSums[2] * fSums[2] / (fSums[0] * fSums[0]);
3890 fCovarianceMatrix[2] = fSums[3] / fSums[0] - fSums[1] * fSums[2] / (fSums[0] * fSums[0]);*/
3897 //_____________________________________________________________________________
3898 Double_t AliTRDtrackerV1::AliTRDLeastSquare::GetFunctionValue(const Double_t *const xpos) const {
3900 // Returns the Function value of the fitted function at a given x-position
3902 return fParams[0] + fParams[1] * (*xpos);
3905 //_____________________________________________________________________________
3906 void AliTRDtrackerV1::AliTRDLeastSquare::GetCovarianceMatrix(Double_t *storage) const {
3908 // Copies the values of the covariance matrix into the storage
3910 memcpy(storage, fCovarianceMatrix, sizeof(Double_t) * 3);
3913 //_____________________________________________________________________________
3914 void AliTRDtrackerV1::AliTRDLeastSquare::Reset(){
3918 memset(fParams, 0, sizeof(Double_t) * 2);
3919 memset(fCovarianceMatrix, 0, sizeof(Double_t) * 3);
3920 memset(fSums, 0, sizeof(Double_t) * 6);
3923 ///////////////////////////////////////////////////////
3925 // Resources of class AliTRDtrackFitterRieman //
3927 ///////////////////////////////////////////////////////
3929 //_____________________________________________________________________________
3930 AliTRDtrackerV1::AliTRDtrackFitterRieman::AliTRDtrackFitterRieman():
3936 fSysClusterError(0.)
3939 // Default constructor
3941 fZfitter = new AliTRDLeastSquare;
3942 fCovarPolY = new TMatrixD(3,3);
3943 fCovarPolZ = new TMatrixD(2,2);
3944 memset(fTracklets, 0, sizeof(AliTRDseedV1 *) * 6);
3945 memset(fParameters, 0, sizeof(Double_t) * 5);
3946 memset(fSumPolY, 0, sizeof(Double_t) * 5);
3947 memset(fSumPolZ, 0, sizeof(Double_t) * 2);
3950 //_____________________________________________________________________________
3951 AliTRDtrackerV1::AliTRDtrackFitterRieman::~AliTRDtrackFitterRieman(){
3955 if(fZfitter) delete fZfitter;
3956 if(fCovarPolY) delete fCovarPolY;
3957 if(fCovarPolZ) delete fCovarPolZ;
3960 //_____________________________________________________________________________
3961 void AliTRDtrackerV1::AliTRDtrackFitterRieman::Reset(){
3966 fTrackFitter->StoreData(kTRUE);
3967 fTrackFitter->ClearPoints();
3973 memset(fTracklets, 0, sizeof(AliTRDseedV1 *) * AliTRDgeometry::kNlayer);
3974 memset(fParameters, 0, sizeof(Double_t) * 5);
3975 memset(fSumPolY, 0, sizeof(Double_t) * 5);
3976 memset(fSumPolZ, 0, sizeof(Double_t) * 2);
3977 for(Int_t irow = 0; irow < fCovarPolY->GetNrows(); irow++)
3978 for(Int_t icol = 0; icol < fCovarPolY->GetNcols(); icol++){
3979 (*fCovarPolY)(irow, icol) = 0.;
3980 if(irow < 2 && icol < 2)
3981 (*fCovarPolZ)(irow, icol) = 0.;
3985 //_____________________________________________________________________________
3986 void AliTRDtrackerV1::AliTRDtrackFitterRieman::SetTracklet(Int_t itr, AliTRDseedV1 *tracklet){
3988 // Add tracklet into the fitter
3990 if(itr >= AliTRDgeometry::kNlayer) return;
3991 fTracklets[itr] = tracklet;
3994 //_____________________________________________________________________________
3995 Double_t AliTRDtrackerV1::AliTRDtrackFitterRieman::Eval(){
3998 // 1. Apply linear transformation and store points in the fitter
3999 // 2. Evaluate the fit
4000 // 3. Check if the result of the fit in z-direction is reasonable
4002 // 3a. Fix the parameters 3 and 4 with the results of a simple least
4004 // 3b. Redo the fit with the fixed parameters
4005 // 4. Store fit results (parameters and errors)
4010 fXref = CalculateReferenceX();
4011 for(Int_t il = 0; il < AliTRDgeometry::kNlayer; il++) UpdateFitters(fTracklets[il]);
4012 if(!fTrackFitter->GetNpoints()) return 1e10;
4014 fTrackFitter->Eval();
4016 fParameters[3] = fTrackFitter->GetParameter(3);
4017 fParameters[4] = fTrackFitter->GetParameter(4);
4018 if(!CheckAcceptable(fParameters[3], fParameters[4])) {
4019 fTrackFitter->FixParameter(3, fZfitter->GetFunctionValue(&fXref));
4020 fTrackFitter->FixParameter(4, fZfitter->GetFunctionParameter(1));
4021 fTrackFitter->Eval();
4022 fTrackFitter->ReleaseParameter(3);
4023 fTrackFitter->ReleaseParameter(4);
4024 fParameters[3] = fTrackFitter->GetParameter(3);
4025 fParameters[4] = fTrackFitter->GetParameter(4);
4027 // Update the Fit Parameters and the errors
4028 fParameters[0] = fTrackFitter->GetParameter(0);
4029 fParameters[1] = fTrackFitter->GetParameter(1);
4030 fParameters[2] = fTrackFitter->GetParameter(2);
4032 // Prepare Covariance estimation
4033 (*fCovarPolY)(0,0) = fSumPolY[0]; (*fCovarPolY)(1,1) = fSumPolY[2]; (*fCovarPolY)(2,2) = fSumPolY[4];
4034 (*fCovarPolY)(1,0) = (*fCovarPolY)(0,1) = fSumPolY[1];
4035 (*fCovarPolY)(2,0) = (*fCovarPolY)(0,2) = fSumPolY[2];
4036 (*fCovarPolY)(2,1) = (*fCovarPolY)(1,2) = fSumPolY[3];
4037 fCovarPolY->Invert();
4038 (*fCovarPolZ)(0,0) = fSumPolZ[0]; (*fCovarPolZ)(1,1) = fSumPolZ[2];
4039 (*fCovarPolZ)(1,0) = (*fCovarPolZ)(0,1) = fSumPolZ[1];
4040 fCovarPolZ->Invert();
4041 return fTrackFitter->GetChisquare() / fTrackFitter->GetNpoints();
4044 //_____________________________________________________________________________
4045 void AliTRDtrackerV1::AliTRDtrackFitterRieman::UpdateFitters(AliTRDseedV1 * const tracklet){
4047 // Does the transformations and updates the fitters
4048 // The following transformation is applied
4050 AliTRDcluster *cl = NULL;
4051 Double_t x, y, z, dx, t, w, we, yerr, zerr;
4053 if(!tracklet || !tracklet->IsOK()) return;
4054 Double_t tilt = tracklet->GetTilt();
4055 for(Int_t itb = 0; itb < AliTRDseedV1::kNclusters; itb++){
4056 if(!(cl = tracklet->GetClusters(itb))) continue;
4057 if(!cl->IsInChamber()) continue;
4058 if (!tracklet->IsUsable(itb)) continue;
4065 uvt[0] = 2. * x * t;
4067 uvt[2] = 2. * tilt * t;
4068 uvt[3] = 2. * tilt * dx * t;
4069 w = 2. * (y + tilt*z) * t;
4070 // error definition changes for the different calls
4072 we *= TMath::Sqrt(cl->GetSigmaY2()+tilt*tilt*cl->GetSigmaZ2());
4073 // Update sums for error calculation
4074 yerr = 1./(TMath::Sqrt(cl->GetSigmaY2()) + fSysClusterError);
4076 zerr = 1./cl->GetSigmaZ2();
4077 for(Int_t ipol = 0; ipol < 5; ipol++){
4078 fSumPolY[ipol] += yerr;
4081 fSumPolZ[ipol] += zerr;
4085 fTrackFitter->AddPoint(uvt, w, we);
4086 fZfitter->AddPoint(&x, z, static_cast<Double_t>(TMath::Sqrt(cl->GetSigmaZ2())));
4090 //_____________________________________________________________________________
4091 Bool_t AliTRDtrackerV1::AliTRDtrackFitterRieman::CheckAcceptable(Double_t offset, Double_t slope){
4093 // Check whether z-results are acceptable
4094 // Definition: Distance between tracklet fit and track fit has to be
4095 // less then half a padlength
4096 // Point of comparision is at the anode wire
4098 Bool_t acceptablez = kTRUE;
4099 Double_t zref = 0.0;
4100 for (Int_t iLayer = 0; iLayer < kNPlanes; iLayer++) {
4101 if(!fTracklets[iLayer]->IsOK()) continue;
4102 zref = offset + slope * (fTracklets[iLayer]->GetX0() - fXref);
4103 if (TMath::Abs(fTracklets[iLayer]->GetZfit(0) - zref) > fTracklets[iLayer]->GetPadLength() * 0.5 + 1.0)
4104 acceptablez = kFALSE;
4109 //_____________________________________________________________________________
4110 Double_t AliTRDtrackerV1::AliTRDtrackFitterRieman::GetYat(Double_t x) const {
4112 // Calculate y position out of the track parameters
4113 // y: R^2 = (x - x0)^2 + (y - y0)^2
4114 // => y = y0 +/- Sqrt(R^2 - (x - x0)^2)
4115 // R = Sqrt() = 1/Curvature
4116 // => y = y0 +/- Sqrt(1/Curvature^2 - (x - x0)^2)
4119 Double_t disc = (x * fParameters[0] + fParameters[1]);
4120 disc = 1 - fParameters[0]*fParameters[2] + fParameters[1]*fParameters[1] - disc*disc;
4122 disc = TMath::Sqrt(disc);
4123 y = (1.0 - disc) / fParameters[0];
4128 //_____________________________________________________________________________
4129 Double_t AliTRDtrackerV1::AliTRDtrackFitterRieman::GetZat(Double_t x) const {
4131 // Return z position for a given x position
4132 // Simple linear function
4134 return fParameters[3] + fParameters[4] * (x - fXref);
4137 //_____________________________________________________________________________
4138 Double_t AliTRDtrackerV1::AliTRDtrackFitterRieman::GetDyDxAt(Double_t x) const {
4140 // Calculate dydx at a given radial position out of the track parameters
4141 // dy: R^2 = (x - x0)^2 + (y - y0)^2
4142 // => y = +/- Sqrt(R^2 - (x - x0)^2) + y0
4143 // => dy/dx = (x - x0)/Sqrt(R^2 - (x - x0)^2)
4144 // Curvature: cr = 1/R = a/Sqrt(1 + b^2 - c*a)
4145 // => dy/dx = (x - x0)/(1/(cr^2) - (x - x0)^2)
4147 Double_t x0 = -fParameters[1] / fParameters[0];
4148 Double_t curvature = GetCurvature();
4150 if (-fParameters[2] * fParameters[0] + fParameters[1] * fParameters[1] + 1 > 0) {
4151 if (1.0/(curvature * curvature) - (x - x0) * (x - x0) > 0.0) {
4152 Double_t yderiv = (x - x0) / TMath::Sqrt(1.0/(curvature * curvature) - (x - x0) * (x - x0));
4153 if (fParameters[0] < 0) yderiv *= -1.0;
4160 //_____________________________________________________________________________
4161 Double_t AliTRDtrackerV1::AliTRDtrackFitterRieman::GetCurvature() const {
4163 // Calculate track curvature
4166 Double_t curvature = 1.0 + fParameters[1]*fParameters[1] - fParameters[2]*fParameters[0];
4167 if (curvature > 0.0)
4168 curvature = fParameters[0] / TMath::Sqrt(curvature);
4172 //_____________________________________________________________________________
4173 void AliTRDtrackerV1::AliTRDtrackFitterRieman::GetCovAt(Double_t x, Double_t *cov) const {
4175 // Error Definition according to gauss error propagation
4177 TMatrixD transform(3,3);
4178 transform(0,0) = transform(1,1) = transform(2,2) = 1;
4179 transform(0,1) = transform(1,2) = x;
4180 transform(0,2) = x*x;
4181 TMatrixD covariance(transform, TMatrixD::kMult, *fCovarPolY);
4182 covariance *= transform.T();
4183 cov[0] = covariance(0,0);
4184 TMatrixD transformZ(2,2);
4185 transformZ(0,0) = transformZ(1,1) = 1;
4186 transformZ(0,1) = x;
4187 TMatrixD covarZ(transformZ, TMatrixD::kMult, *fCovarPolZ);
4188 covarZ *= transformZ.T();
4189 cov[1] = covarZ(0,0);
4193 //____________________________________________________________________
4194 Double_t AliTRDtrackerV1::AliTRDtrackFitterRieman::CalculateReferenceX(){
4196 // Calculates the reference x-position for the tilted Rieman fit defined as middle
4197 // of the stack (middle between layers 2 and 3). For the calculation all the tracklets
4198 // are taken into account
4200 // Parameters: - Array of tracklets(AliTRDseedV1)
4202 // Output: - The reference x-position(Float_t)
4204 Int_t nDistances = 0;
4205 Float_t meanDistance = 0.;
4206 Int_t startIndex = 5;
4207 for(Int_t il =5; il > 0; il--){
4208 if(fTracklets[il]->IsOK() && fTracklets[il -1]->IsOK()){
4209 Float_t xdiff = fTracklets[il]->GetX0() - fTracklets[il -1]->GetX0();
4210 meanDistance += xdiff;
4213 if(fTracklets[il]->IsOK()) startIndex = il;
4215 if(fTracklets[0]->IsOK()) startIndex = 0;
4217 // We should normally never get here
4218 Float_t xpos[2]; memset(xpos, 0, sizeof(Float_t) * 2);
4219 Int_t iok = 0, idiff = 0;
4220 // This attempt is worse and should be avoided:
4221 // check for two chambers which are OK and repeat this without taking the mean value
4222 // Strategy avoids a division by 0;
4223 for(Int_t il = 5; il >= 0; il--){
4224 if(fTracklets[il]->IsOK()){
4225 xpos[iok] = fTracklets[il]->GetX0();
4229 if(iok) idiff++; // to get the right difference;
4233 meanDistance = (xpos[0] - xpos[1])/idiff;
4236 // we have do not even have 2 layers which are OK? The we do not need to fit at all
4241 meanDistance /= nDistances;
4243 return fTracklets[startIndex]->GetX0() + (2.5 - startIndex) * meanDistance - 0.5 * (AliTRDgeometry::AmThick() + AliTRDgeometry::DrThick());