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 Double_t AliTRDtrackerV1::fgTopologicQA[kNConfigs] = {
65 0.5112, 0.5112, 0.5112, 0.0786, 0.0786,
66 0.0786, 0.0786, 0.0579, 0.0579, 0.0474,
67 0.0474, 0.0408, 0.0335, 0.0335, 0.0335
69 const Double_t AliTRDtrackerV1::fgkX0[kNPlanes] = {
70 300.2, 312.8, 325.4, 338.0, 350.6, 363.2};
71 // Number of Time Bins/chamber should be also stored independently by the traker
72 // (also in AliTRDReconstructor) in oder to be able to run HLT. Fix TODO
73 Int_t AliTRDtrackerV1::fgNTimeBins = 0;
74 AliRieman* AliTRDtrackerV1::fgRieman = NULL;
75 TLinearFitter* AliTRDtrackerV1::fgTiltedRieman = NULL;
76 TLinearFitter* AliTRDtrackerV1::fgTiltedRiemanConstrained = NULL;
78 //____________________________________________________________________
79 AliTRDtrackerV1::AliTRDtrackerV1(AliTRDReconstructor *rec)
81 ,fkReconstructor(NULL)
91 // Default constructor.
94 SetReconstructor(rec); // initialize reconstructor
96 // initialize geometry
97 if(!AliGeomManager::GetGeometry()){
98 AliFatal("Could not get geometry.");
100 fGeom = new AliTRDgeometry();
101 fGeom->CreateClusterMatrixArray();
102 TGeoHMatrix *matrix = NULL;
103 Double_t loc[] = {0., 0., 0.};
104 Double_t glb[] = {0., 0., 0.};
105 for(Int_t ily=kNPlanes; ily--;){
107 while(!(matrix = fGeom->GetClusterMatrix(AliTRDgeometry::GetDetector(ily, 2, ism)))) ism++;
109 AliError(Form("Could not get transformation matrix for layer %d. Use default.", ily));
110 fR[ily] = fgkX0[ily];
113 matrix->LocalToMaster(loc, glb);
114 fR[ily] = glb[0]+ AliTRDgeometry::AnodePos()-.5*AliTRDgeometry::AmThick() - AliTRDgeometry::DrThick();
117 // initialize cluster containers
118 for (Int_t isector = 0; isector < AliTRDgeometry::kNsector; isector++) new(&fTrSec[isector]) AliTRDtrackingSector(fGeom, isector);
121 memset(fTrackQuality, 0, kMaxTracksStack*sizeof(Double_t));
122 memset(fSeedLayer, 0, kMaxTracksStack*sizeof(Int_t));
123 memset(fSeedTB, 0, kNSeedPlanes*sizeof(AliTRDchamberTimeBin*));
124 fTracksESD = new TClonesArray("AliESDtrack", 2*kMaxTracksStack);
125 fTracksESD->SetOwner();
128 //____________________________________________________________________
129 AliTRDtrackerV1::~AliTRDtrackerV1()
135 if(fgRieman) delete fgRieman; fgRieman = NULL;
136 if(fgTiltedRieman) delete fgTiltedRieman; fgTiltedRieman = NULL;
137 if(fgTiltedRiemanConstrained) delete fgTiltedRiemanConstrained; fgTiltedRiemanConstrained = NULL;
138 for(Int_t isl =0; isl<kNSeedPlanes; isl++) if(fSeedTB[isl]) delete fSeedTB[isl];
139 if(fTracksESD){ fTracksESD->Delete(); delete fTracksESD; }
140 if(fTracks) {fTracks->Delete(); delete fTracks;}
141 if(fTracklets) {fTracklets->Delete(); delete fTracklets;}
143 fClusters->Delete(); delete fClusters;
145 if(fGeom) delete fGeom;
148 //____________________________________________________________________
149 Int_t AliTRDtrackerV1::Clusters2Tracks(AliESDEvent *esd)
152 // Steering stand alone tracking for full TRD detector
155 // esd : The ESD event. On output it contains
156 // the ESD tracks found in TRD.
159 // Number of tracks found in the TRD detector.
161 // Detailed description
162 // 1. Launch individual SM trackers.
163 // See AliTRDtrackerV1::Clusters2TracksSM() for details.
167 AliError("Reconstruction configuration not initialized. Call first AliTRDReconstructor::SetRecoParam().");
171 //AliInfo("Start Track Finder ...");
173 for(int ism=0; ism<AliTRDgeometry::kNsector; ism++){
174 // for(int ism=1; ism<2; ism++){
175 //AliInfo(Form("Processing supermodule %i ...", ism));
176 ntracks += Clusters2TracksSM(ism, esd);
178 AliInfo(Form("Number of tracks: !TRDin[%d]", ntracks));
183 //_____________________________________________________________________________
184 Bool_t AliTRDtrackerV1::GetTrackPoint(Int_t index, AliTrackPoint &p) const
186 //AliInfo(Form("Asking for tracklet %d", index));
188 // reset position of the point before using it
189 p.SetXYZ(0., 0., 0.);
190 AliTRDseedV1 *tracklet = GetTracklet(index);
191 if (!tracklet) return kFALSE;
193 // get detector for this tracklet
194 Int_t det = tracklet->GetDetector();
195 Int_t sec = fGeom->GetSector(det);
196 Double_t alpha = (sec+.5)*AliTRDgeometry::GetAlpha(),
197 sinA = TMath::Sin(alpha),
198 cosA = TMath::Cos(alpha);
200 local[0] = tracklet->GetX();
201 local[1] = tracklet->GetY();
202 local[2] = tracklet->GetZ();
204 fGeom->RotateBack(det, local, global);
206 Double_t cov2D[3]; Float_t cov[6];
207 tracklet->GetCovAt(local[0], cov2D);
208 cov[0] = cov2D[0]*sinA*sinA;
209 cov[1] =-cov2D[0]*sinA*cosA;
210 cov[2] =-cov2D[1]*sinA;
211 cov[3] = cov2D[0]*cosA*cosA;
212 cov[4] = cov2D[1]*cosA;
214 // store the global position of the tracklet and its covariance matrix in the track point
215 p.SetXYZ(global[0],global[1],global[2], cov);
218 AliGeomManager::ELayerID iLayer = AliGeomManager::ELayerID(AliGeomManager::kTRD1+fGeom->GetLayer(det));
219 Int_t modId = fGeom->GetSector(det) * AliTRDgeometry::kNstack + fGeom->GetStack(det);
220 UShort_t volid = AliGeomManager::LayerToVolUID(iLayer, modId);
221 p.SetVolumeID(volid);
226 //____________________________________________________________________
227 TLinearFitter* AliTRDtrackerV1::GetTiltedRiemanFitter()
229 if(!fgTiltedRieman) fgTiltedRieman = new TLinearFitter(4, "hyp4");
230 return fgTiltedRieman;
233 //____________________________________________________________________
234 TLinearFitter* AliTRDtrackerV1::GetTiltedRiemanFitterConstraint()
236 if(!fgTiltedRiemanConstrained) fgTiltedRiemanConstrained = new TLinearFitter(2, "hyp2");
237 return fgTiltedRiemanConstrained;
240 //____________________________________________________________________
241 AliRieman* AliTRDtrackerV1::GetRiemanFitter()
243 if(!fgRieman) fgRieman = new AliRieman(AliTRDseedV1::kNtb * AliTRDgeometry::kNlayer);
247 //_____________________________________________________________________________
248 Int_t AliTRDtrackerV1::PropagateBack(AliESDEvent *event)
250 // Propagation of ESD tracks from TPC to TOF detectors and building of the TRD track. For building
251 // a TRD track an ESD track is used as seed. The informations obtained on the TRD track (measured points,
252 // covariance, PID, etc.) are than used to update the corresponding ESD track.
253 // Each track seed is first propagated to the geometrical limit of the TRD detector.
254 // Its prolongation is searched in the TRD and if corresponding clusters are found tracklets are
255 // constructed out of them (see AliTRDseedV1::AttachClusters()) and the track is updated.
256 // Otherwise the ESD track is left unchanged.
258 // The following steps are performed:
259 // 1. Selection of tracks based on the variance in the y-z plane.
260 // 2. Propagation to the geometrical limit of the TRD volume. If track propagation fails the AliESDtrack::kTRDStop is set.
261 // 3. Prolongation inside the fiducial volume (see AliTRDtrackerV1::FollowBackProlongation()) and marking
262 // the following status bits:
263 // - AliESDtrack::kTRDin - if the tracks enters the TRD fiducial volume
264 // - AliESDtrack::kTRDStop - if the tracks fails propagation
265 // - AliESDtrack::kTRDbackup - if the tracks fulfills chi2 conditions and qualify for refitting
266 // 4. Writting to friends, PID, MC label, quality etc. Setting status bit AliESDtrack::kTRDout.
267 // 5. Propagation to TOF. If track propagation fails the AliESDtrack::kTRDStop is set.
270 if(!fClusters || !fClusters->GetEntriesFast()){
271 AliInfo("No TRD clusters");
274 AliTRDCalibraFillHisto *calibra = AliTRDCalibraFillHisto::Instance(); // Calibration monitor
275 if (!calibra) AliInfo("Could not get Calibra instance");
276 if (!fgNTimeBins) fgNTimeBins = fkReconstructor->GetNTimeBins();
279 Int_t nFound = 0, // number of tracks found
280 nBacked = 0, // number of tracks backed up for refit
281 nSeeds = 0, // total number of ESD seeds
282 nTRDseeds= 0, // number of seeds in the TRD acceptance
283 nTPCseeds= 0; // number of TPC seeds
284 Float_t foundMin = 20.0;
286 Float_t *quality = NULL;
288 nSeeds = event->GetNumberOfTracks();
289 // Sort tracks according to quality
290 // (covariance in the yz plane)
292 quality = new Float_t[nSeeds];
293 index = new Int_t[4*nSeeds];
294 for (Int_t iSeed = nSeeds; iSeed--;) {
295 AliESDtrack *seed = event->GetTrack(iSeed);
296 Double_t covariance[15];
297 seed->GetExternalCovariance(covariance);
298 quality[iSeed] = covariance[0] + covariance[2];
300 TMath::Sort(nSeeds, quality, index,kFALSE);
303 // Propagate all seeds
306 for (Int_t iSeed = 0; iSeed < nSeeds; iSeed++) {
308 // Get the seeds in sorted sequence
309 AliESDtrack *seed = event->GetTrack(index[iSeed]);
310 Float_t p4 = seed->GetC(seed->GetBz());
312 // Check the seed status
313 ULong_t status = seed->GetStatus();
314 if ((status & AliESDtrack::kTPCout) == 0) continue;
315 if ((status & AliESDtrack::kTRDout) != 0) continue;
317 // Propagate to the entrance in the TRD mother volume
318 track.~AliTRDtrackV1();
319 new(&track) AliTRDtrackV1(*seed);
320 if(AliTRDgeometry::GetXtrdBeg() > (AliTRDReconstructor::GetMaxStep() + track.GetX()) && !PropagateToX(track, AliTRDgeometry::GetXtrdBeg(), AliTRDReconstructor::GetMaxStep())){
321 seed->UpdateTrackParams(&track, AliESDtrack::kTRDStop);
324 if(!AdjustSector(&track)){
325 seed->UpdateTrackParams(&track, AliESDtrack::kTRDStop);
328 if(TMath::Abs(track.GetSnp()) > AliTRDReconstructor::GetMaxSnp()) {
329 seed->UpdateTrackParams(&track, AliESDtrack::kTRDStop);
333 AliDebug(2, Form("TRD propagate TPC seed[%d] = %d.", iSeed, index[iSeed]));
334 // store track status at TRD entrance
335 seed->UpdateTrackParams(&track, AliESDtrack::kTRDbackup);
337 // prepare track and do propagation in the TRD
338 track.SetReconstructor(fkReconstructor);
339 track.SetKink(Bool_t(seed->GetKinkIndex(0)));
340 track.SetPrimary(status & AliESDtrack::kTPCin);
341 expectedClr = FollowBackProlongation(track);
342 // check if track entered the TRD fiducial volume
343 if(track.GetTrackIn()){
344 seed->UpdateTrackParams(&track, AliESDtrack::kTRDin);
347 // check if track was stopped in the TRD
349 seed->UpdateTrackParams(&track, AliESDtrack::kTRDStop);
355 // computes PID for track
357 // update calibration references using this track
358 if(calibra->GetHisto2d()) calibra->UpdateHistogramsV1(&track);
359 // save calibration object
360 if (fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) > 0) {
361 AliTRDtrackV1 *calibTrack = new AliTRDtrackV1(track);
362 calibTrack->SetOwner();
363 seed->AddCalibObject(calibTrack);
366 seed->UpdateTrackParams(&track, AliESDtrack::kTRDout);
367 track.UpdateESDtrack(seed);
370 if ((TMath::Abs(track.GetC(track.GetBz()) - p4) / TMath::Abs(p4) < 0.2) ||(track.Pt() > 0.8)) {
372 // Make backup for back propagation
373 Int_t foundClr = track.GetNumberOfClusters();
374 if (foundClr >= foundMin) {
375 track.CookLabel(1. - AliTRDReconstructor::GetLabelFraction());
376 //if(track.GetBackupTrack()) UseClusters(track.GetBackupTrack());
378 // Sign only gold tracks
379 if (track.GetChi2() / track.GetNumberOfClusters() < 4) {
380 //if ((seed->GetKinkIndex(0) == 0) && (track.Pt() < 1.5)) UseClusters(&track);
382 Bool_t isGold = kFALSE;
385 if (track.GetChi2() / track.GetNumberOfClusters() < 5) {
386 if (track.GetBackupTrack()) seed->UpdateTrackParams(track.GetBackupTrack(),AliESDtrack::kTRDbackup);
392 if ((!isGold) && (track.GetNCross() == 0) && (track.GetChi2() / track.GetNumberOfClusters() < 7)) {
393 //seed->UpdateTrackParams(track, AliESDtrack::kTRDbackup);
394 if (track.GetBackupTrack()) seed->UpdateTrackParams(track.GetBackupTrack(),AliESDtrack::kTRDbackup);
399 if ((!isGold) && (track.GetBackupTrack())) {
400 if ((track.GetBackupTrack()->GetNumberOfClusters() > foundMin) && ((track.GetBackupTrack()->GetChi2()/(track.GetBackupTrack()->GetNumberOfClusters()+1)) < 7)) {
401 seed->UpdateTrackParams(track.GetBackupTrack(),AliESDtrack::kTRDbackup);
409 // Propagation to the TOF
410 if(!(seed->GetStatus()&AliESDtrack::kTRDStop)) {
411 Int_t sm = track.GetSector();
412 // default value in case we have problems with the geometry.
413 Double_t xtof = 371.;
414 //Calculate radial position of the beginning of the TOF
415 //mother volume. In order to avoid mixing of the TRD
416 //and TOF modules some hard values are needed. This are:
417 //1. The path to the TOF module.
418 //2. The width of the TOF (29.05 cm)
419 //(with the help of Annalisa de Caro Mar-17-2009)
421 gGeoManager->cd(Form("/ALIC_1/B077_1/BSEGMO%d_1/BTOF%d_1", sm, sm));
422 TGeoHMatrix *m = NULL;
423 Double_t loc[]={0., 0., -.5*29.05}, glob[3];
425 if((m=gGeoManager->GetCurrentMatrix())){
426 m->LocalToMaster(loc, glob);
427 xtof = TMath::Sqrt(glob[0]*glob[0]+glob[1]*glob[1]);
430 if(xtof > (AliTRDReconstructor::GetMaxStep() + track.GetX()) && !PropagateToX(track, xtof, AliTRDReconstructor::GetMaxStep())){
431 seed->UpdateTrackParams(&track, AliESDtrack::kTRDStop);
434 if(!AdjustSector(&track)){
435 seed->UpdateTrackParams(&track, AliESDtrack::kTRDStop);
438 if(TMath::Abs(track.GetSnp()) > AliTRDReconstructor::GetMaxSnp()){
439 seed->UpdateTrackParams(&track, AliESDtrack::kTRDStop);
442 //seed->UpdateTrackParams(&track, AliESDtrack::kTRDout);
443 // TODO obsolete - delete
444 seed->SetTRDQuality(track.StatusForTOF());
446 seed->SetTRDBudget(track.GetBudget(0));
448 if(index) delete [] index;
449 if(quality) delete [] quality;
451 AliInfo(Form("Number of seeds: TPCout[%d] TRDin[%d]", nTPCseeds, nTRDseeds));
452 AliInfo(Form("Number of tracks: TRDout[%d] TRDbackup[%d]", nFound, nBacked));
454 // run stand alone tracking
455 if (fkReconstructor->IsSeeding()) Clusters2Tracks(event);
461 //____________________________________________________________________
462 Int_t AliTRDtrackerV1::RefitInward(AliESDEvent *event)
465 // Refits tracks within the TRD. The ESD event is expected to contain seeds
466 // at the outer part of the TRD.
467 // The tracks are propagated to the innermost time bin
468 // of the TRD and the ESD event is updated
469 // Origin: Thomas KUHR (Thomas.Kuhr@cern.ch)
472 Int_t nseed = 0; // contor for loaded seeds
473 Int_t found = 0; // contor for updated TRD tracks
476 if(!fClusters || !fClusters->GetEntriesFast()){
477 AliInfo("No TRD clusters");
481 for (Int_t itrack = 0; itrack < event->GetNumberOfTracks(); itrack++) {
482 AliESDtrack *seed = event->GetTrack(itrack);
483 ULong_t status = seed->GetStatus();
485 new(&track) AliTRDtrackV1(*seed);
486 if (track.GetX() < 270.0) {
487 seed->UpdateTrackParams(&track, AliESDtrack::kTRDbackup);
491 // reject tracks which failed propagation in the TRD or
492 // are produced by the TRD stand alone tracker
493 if(!(status & AliESDtrack::kTRDout)) continue;
494 if(!(status & AliESDtrack::kTRDin)) continue;
497 track.ResetCovariance(50.0);
499 // do the propagation and processing
500 Bool_t kUPDATE = kFALSE;
501 Double_t xTPC = 250.0;
502 if(FollowProlongation(track)){
503 // Update the friend track
504 if (fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) > 0){
505 TObject *o = NULL; Int_t ic = 0;
506 AliTRDtrackV1 *calibTrack = NULL;
507 while((o = seed->GetCalibObject(ic++))){
508 if(!(calibTrack = dynamic_cast<AliTRDtrackV1*>(o))) continue;
509 calibTrack->SetTrackOut(&track);
514 if (PropagateToX(track, xTPC, AliTRDReconstructor::GetMaxStep())) { // -with update
515 seed->UpdateTrackParams(&track, AliESDtrack::kTRDrefit);
521 // Prolongate to TPC without update
523 AliTRDtrackV1 tt(*seed);
524 if (PropagateToX(tt, xTPC, AliTRDReconstructor::GetMaxStep())) seed->UpdateTrackParams(&tt, AliESDtrack::kTRDbackup);
527 AliInfo(Form("Number of seeds: TRDout[%d]", nseed));
528 AliInfo(Form("Number of tracks: TRDrefit[%d]", found));
533 //____________________________________________________________________
534 Int_t AliTRDtrackerV1::FollowProlongation(AliTRDtrackV1 &t)
536 // Extrapolates the TRD track in the TPC direction.
539 // t : the TRD track which has to be extrapolated
542 // number of clusters attached to the track
544 // Detailed description
546 // Starting from current radial position of track <t> this function
547 // extrapolates the track through the 6 TRD layers. The following steps
548 // are being performed for each plane:
550 // a. get plane limits in the local x direction
551 // b. check crossing sectors
552 // c. check track inclination
553 // 2. search tracklet in the tracker list (see GetTracklet() for details)
554 // 3. evaluate material budget using the geo manager
555 // 4. propagate and update track using the tracklet information.
560 Int_t nClustersExpected = 0;
561 for (Int_t iplane = kNPlanes; iplane--;) {
563 AliTRDseedV1 *tracklet = GetTracklet(&t, iplane, index);
564 AliDebug(2, Form("Tracklet[%p] ly[%d] idx[%d]", (void*)tracklet, iplane, index));
565 if(!tracklet) continue;
566 if(!tracklet->IsOK()){
567 AliDebug(1, Form("Tracklet Det[%d] !OK", tracklet->GetDetector()));
570 Double_t x = tracklet->GetX();//GetX0();
571 // reject tracklets which are not considered for inward refit
572 if(x > t.GetX()+AliTRDReconstructor::GetMaxStep()) continue;
574 // append tracklet to track
575 t.SetTracklet(tracklet, index);
577 if (x < (t.GetX()-AliTRDReconstructor::GetMaxStep()) && !PropagateToX(t, x+AliTRDReconstructor::GetMaxStep(), AliTRDReconstructor::GetMaxStep())) break;
578 if (!AdjustSector(&t)) break;
580 // Start global position
584 // End global position
585 Double_t alpha = t.GetAlpha(), y, z;
586 if (!t.GetProlongation(x,y,z)) break;
588 xyz1[0] = x * TMath::Cos(alpha) - y * TMath::Sin(alpha);
589 xyz1[1] = x * TMath::Sin(alpha) + y * TMath::Cos(alpha);
592 Double_t length = TMath::Sqrt(
593 (xyz0[0]-xyz1[0])*(xyz0[0]-xyz1[0]) +
594 (xyz0[1]-xyz1[1])*(xyz0[1]-xyz1[1]) +
595 (xyz0[2]-xyz1[2])*(xyz0[2]-xyz1[2])
598 // Get material budget
600 if(AliTracker::MeanMaterialBudget(xyz0, xyz1, param)<=0.) break;
601 Double_t xrho= param[0]*param[4];
602 Double_t xx0 = param[1]; // Get mean propagation parameters
604 // Propagate and update
605 t.PropagateTo(x, xx0, xrho);
606 if (!AdjustSector(&t)) break;
609 Double_t cov[3]; tracklet->GetCovAt(x, cov);
610 Double_t p[2] = { tracklet->GetY(), tracklet->GetZ()};
611 Double_t chi2 = ((AliExternalTrackParam)t).GetPredictedChi2(p, cov);
612 if (chi2 < 1e+10 && ((AliExternalTrackParam&)t).Update(p, cov)){
613 // Register info to track
614 t.SetNumberOfClusters();
616 nClustersExpected += tracklet->GetN();
620 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) > 1){
622 for(int iplane=0; iplane<AliTRDgeometry::kNlayer; iplane++){
623 AliTRDseedV1 *tracklet = GetTracklet(&t, iplane, index);
624 if(!tracklet) continue;
625 t.SetTracklet(tracklet, index);
628 if(fkReconstructor->IsDebugStreaming()){
629 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
630 TTreeSRedirector &cstreamer = *fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker);
631 AliTRDtrackV1 track(t);
633 cstreamer << "FollowProlongation"
634 << "EventNumber=" << eventNumber
635 << "ncl=" << nClustersExpected
636 << "track.=" << &track
640 return nClustersExpected;
644 //_____________________________________________________________________________
645 Int_t AliTRDtrackerV1::FollowBackProlongation(AliTRDtrackV1 &t)
647 // Extrapolates/Build the TRD track in the TOF direction.
650 // t : the TRD track which has to be extrapolated
653 // number of clusters attached to the track
655 // Starting from current radial position of track <t> this function
656 // extrapolates the track through the 6 TRD layers. The following steps
657 // are being performed for each plane:
658 // 1. Propagate track to the entrance of the next chamber:
659 // - get chamber limits in the radial direction
660 // - check crossing sectors
661 // - check track inclination
662 // - check track prolongation against boundary conditions (see exclusion boundaries on AliTRDgeometry::IsOnBoundary())
663 // 2. Build tracklet (see AliTRDseed::AttachClusters() for details) for this layer if needed. If only
664 // Kalman filter is needed and tracklets are already linked to the track this step is skipped.
665 // 3. Fit tracklet using the information from the Kalman filter.
666 // 4. Propagate and update track at reference radial position of the tracklet.
667 // 5. Register tracklet with the tracker and track; update pulls monitoring.
670 // 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:
671 // - AliTRDtrackV1::kProlongation : track prolongation failed
672 // - AliTRDtrackV1::kPropagation : track prolongation failed
673 // - AliTRDtrackV1::kAdjustSector : failed during sector crossing
674 // - AliTRDtrackV1::kSnp : too large bending
675 // - AliTRDtrackV1::kTrackletInit : fail to initialize tracklet
676 // - AliTRDtrackV1::kUpdate : fail to attach clusters or fit the tracklet
677 // - AliTRDtrackV1::kUnknown : anything which is not covered before
678 // 2. By default the status of the track before first TRD update is saved.
683 // Alexandru Bercuci <A.Bercuci@gsi.de>
687 Double_t driftLength = .5*AliTRDgeometry::AmThick() + AliTRDgeometry::DrThick();
688 AliTRDtrackingChamber *chamber = NULL;
690 Int_t debugLevel = fkReconstructor->IsDebugStreaming() ? fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) : 0;
691 TTreeSRedirector *cstreamer = fkReconstructor->IsDebugStreaming() ? fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker) : 0x0;
693 Bool_t kStoreIn(kTRUE), // toggel store track params. at TRD entry
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;
711 AliDebug(4, Form("SA[%c] Start[%d]\n"
712 " [0]idx[%d] traklet[%p]\n"
713 " [1]idx[%d] traklet[%p]\n"
714 " [2]idx[%d] traklet[%p]\n"
715 " [3]idx[%d] traklet[%p]\n"
716 " [4]idx[%d] traklet[%p]\n"
717 " [5]idx[%d] traklet[%p]"
718 , kStandAlone?'y':'n', startLayer
719 , t.GetTrackletIndex(0), (void*)tracklets[0]
720 , t.GetTrackletIndex(1), (void*)tracklets[1]
721 , t.GetTrackletIndex(2), (void*)tracklets[2]
722 , t.GetTrackletIndex(3), (void*)tracklets[3]
723 , t.GetTrackletIndex(4), (void*)tracklets[4]
724 , t.GetTrackletIndex(5), (void*)tracklets[5]));
726 // Loop through the TRD layers
727 TGeoHMatrix *matrix = NULL;
729 for (Int_t ily=startLayer, sm=-1, stk=-1, det=-1; ily < AliTRDgeometry::kNlayer; ily++) {
730 AliDebug(2, Form("Propagate to x[%d] = %7.2f", ily, fR[ily]));
732 // rough estimate of the entry point
733 if (!t.GetProlongation(fR[ily], y, z)){
735 t.SetStatus(AliTRDtrackV1::kProlongation);
736 AliDebug(4, Form("Failed Rough Prolongation to ly[%d] x[%7.2f] y[%7.2f] z[%7.2f]", ily, fR[ily], y, z));
740 // find sector / stack / detector
742 // TODO cross check with y value !
743 stk = fGeom->GetStack(z, ily);
744 det = stk>=0 ? AliTRDgeometry::GetDetector(ily, stk, sm) : -1;
745 matrix = det>=0 ? fGeom->GetClusterMatrix(det) : NULL;
746 AliDebug(3, Form("Propagate to det[%3d]", det));
748 // check if supermodule/chamber is installed
749 if( !fGeom->GetSMstatus(sm) ||
751 fGeom->IsHole(ily, stk, sm) ||
753 AliDebug(4, Form("Missing Geometry ly[%d]. Guess radial position", ily));
754 // propagate to the default radial position
755 if(fR[ily] > (AliTRDReconstructor::GetMaxStep() + t.GetX()) && !PropagateToX(t, fR[ily], AliTRDReconstructor::GetMaxStep())){
757 t.SetStatus(AliTRDtrackV1::kPropagation);
758 AliDebug(4, "Failed Propagation [Missing Geometry]");
761 if(!AdjustSector(&t)){
763 t.SetStatus(AliTRDtrackV1::kAdjustSector);
764 AliDebug(4, "Failed Adjust Sector [Missing Geometry]");
767 if(TMath::Abs(t.GetSnp()) > AliTRDReconstructor::GetMaxSnp()){
769 t.SetStatus(AliTRDtrackV1::kSnp);
770 AliDebug(4, "Failed Max Snp [Missing Geometry]");
773 t.SetStatus(AliTRDtrackV1::kGeometry, ily);
777 // retrieve rotation matrix for the current chamber
778 Double_t loc[] = {AliTRDgeometry::AnodePos()- driftLength, 0., 0.};
779 Double_t glb[] = {0., 0., 0.};
780 matrix->LocalToMaster(loc, glb);
782 // Propagate to the radial distance of the current layer
783 x = glb[0] - AliTRDReconstructor::GetMaxStep();
784 if(x > (AliTRDReconstructor::GetMaxStep() + t.GetX()) && !PropagateToX(t, x, AliTRDReconstructor::GetMaxStep())){
786 t.SetStatus(AliTRDtrackV1::kPropagation);
787 AliDebug(4, Form("Failed Initial Propagation to x[%7.2f]", x));
790 if(!AdjustSector(&t)){
792 t.SetStatus(AliTRDtrackV1::kAdjustSector);
793 AliDebug(4, "Failed Adjust Sector Start");
796 if(TMath::Abs(t.GetSnp()) > AliTRDReconstructor::GetMaxSnp()) {
798 t.SetStatus(AliTRDtrackV1::kSnp);
799 AliDebug(4, Form("Failed Max Snp[%f] MaxSnp[%f]", t.GetSnp(), AliTRDReconstructor::GetMaxSnp()));
802 Bool_t doRecalculate = kFALSE;
803 if(sm != t.GetSector()){
805 doRecalculate = kTRUE;
807 if(stk != fGeom->GetStack(z, ily)){
808 stk = fGeom->GetStack(z, ily);
809 doRecalculate = kTRUE;
812 det = AliTRDgeometry::GetDetector(ily, stk, sm);
813 if(!(matrix = fGeom->GetClusterMatrix(det))){
814 t.SetStatus(AliTRDtrackV1::kGeometry, ily);
815 AliDebug(4, Form("Failed Geometry Matrix ly[%d]", ily));
818 matrix->LocalToMaster(loc, glb);
819 x = glb[0] - AliTRDReconstructor::GetMaxStep();
822 // check if track is well inside fiducial volume
823 if (!t.GetProlongation(x+AliTRDReconstructor::GetMaxStep(), y, z)) {
825 t.SetStatus(AliTRDtrackV1::kProlongation);
826 AliDebug(4, Form("Failed Prolongation to x[%7.2f] y[%7.2f] z[%7.2f]", x+AliTRDReconstructor::GetMaxStep(), y, z));
829 if(fGeom->IsOnBoundary(det, y, z, .5)){
830 t.SetStatus(AliTRDtrackV1::kBoundary, ily);
831 AliDebug(4, "Failed Track on Boundary");
834 // mark track as entering the FIDUCIAL volume of TRD
840 ptrTracklet = tracklets[ily];
841 if(!ptrTracklet){ // BUILD TRACKLET
842 AliDebug(3, Form("Building tracklet det[%d]", det));
843 // check data in supermodule
844 if(!fTrSec[sm].GetNChambers()){
845 t.SetStatus(AliTRDtrackV1::kNoClusters, ily);
846 AliDebug(4, "Failed NoClusters");
849 if(fTrSec[sm].GetX(ily) < 1.){
850 t.SetStatus(AliTRDtrackV1::kNoClusters, ily);
851 AliDebug(4, "Failed NoX");
855 // check data in chamber
856 if(!(chamber = fTrSec[sm].GetChamber(stk, ily))){
857 t.SetStatus(AliTRDtrackV1::kNoClusters, ily);
858 AliDebug(4, "Failed No Detector");
861 if(chamber->GetNClusters() < fgNTimeBins*fkRecoParam ->GetFindableClusters()){
862 t.SetStatus(AliTRDtrackV1::kNoClusters, ily);
863 AliDebug(4, "Failed Not Enough Clusters in Detector");
867 tracklet.~AliTRDseedV1();
868 ptrTracklet = new(&tracklet) AliTRDseedV1(det);
869 ptrTracklet->SetReconstructor(fkReconstructor);
870 ptrTracklet->SetKink(t.IsKink());
871 ptrTracklet->SetPrimary(t.IsPrimary());
872 ptrTracklet->SetPadPlane(fGeom->GetPadPlane(ily, stk));
873 ptrTracklet->SetX0(glb[0]+driftLength);
874 if(!ptrTracklet->Init(&t)){
876 t.SetStatus(AliTRDtrackV1::kTrackletInit);
877 AliDebug(4, "Failed Tracklet Init");
880 if(!ptrTracklet->AttachClusters(chamber, kTRUE)){
881 t.SetStatus(AliTRDtrackV1::kNoAttach, ily);
883 AliTRDseedV1 trackletCp(*ptrTracklet);
884 UChar_t status(t.GetStatusTRD(ily));
885 (*cstreamer) << "FollowBackProlongation2"
886 <<"status=" << status
887 <<"tracklet.=" << &trackletCp
890 AliDebug(4, "Failed Attach Clusters");
893 AliDebug(3, Form("Number of Clusters in Tracklet: %d", ptrTracklet->GetN()));
894 if(ptrTracklet->GetN() < fgNTimeBins*fkRecoParam->GetFindableClusters()){
895 t.SetStatus(AliTRDtrackV1::kNoClustersTracklet, ily);
897 AliTRDseedV1 trackletCp(*ptrTracklet);
898 UChar_t status(t.GetStatusTRD(ily));
899 (*cstreamer) << "FollowBackProlongation2"
900 <<"status=" << status
901 <<"tracklet.=" << &trackletCp
904 AliDebug(4, "Failed N Clusters Attached");
907 ptrTracklet->UpdateUsed();
908 } else AliDebug(2, Form("Use external tracklet ly[%d]", ily));
909 // propagate track to the radial position of the tracklet
912 // tilt correction options
914 // 2 : pseudo tilt correction
915 if(!ptrTracklet->Fit(2)){
916 t.SetStatus(AliTRDtrackV1::kNoFit, ily);
917 AliDebug(4, "Failed Tracklet Fit");
920 x = ptrTracklet->GetX(); //GetX0();
921 if(x > (AliTRDReconstructor::GetMaxStep() + t.GetX()) && !PropagateToX(t, x, AliTRDReconstructor::GetMaxStep())) {
923 t.SetStatus(AliTRDtrackV1::kPropagation);
924 AliDebug(4, Form("Failed Propagation to Tracklet x[%7.2f]", x));
927 if(!AdjustSector(&t)) {
929 t.SetStatus(AliTRDtrackV1::kAdjustSector);
930 AliDebug(4, "Failed Adjust Sector");
933 if(TMath::Abs(t.GetSnp()) > AliTRDReconstructor::GetMaxSnp()) {
935 t.SetStatus(AliTRDtrackV1::kSnp);
936 AliDebug(4, Form("Failed Max Snp[%f] MaxSnp[%f]", t.GetSnp(), AliTRDReconstructor::GetMaxSnp()));
939 Double_t cov[3]; ptrTracklet->GetCovAt(x, cov);
940 Double_t p[2] = { ptrTracklet->GetY(), ptrTracklet->GetZ()};
941 Double_t chi2 = ((AliExternalTrackParam)t).GetPredictedChi2(p, cov);
942 // update Kalman with the TRD measurement
943 if(chi2>1e+10){ // TODO
944 t.SetStatus(AliTRDtrackV1::kChi2, ily);
946 UChar_t status(t.GetStatusTRD());
947 AliTRDseedV1 trackletCp(*ptrTracklet);
948 AliTRDtrackV1 trackCp(t);
950 (*cstreamer) << "FollowBackProlongation1"
951 << "status=" << status
952 << "tracklet.=" << &trackletCp
953 << "track.=" << &trackCp
956 AliDebug(4, Form("Failed Chi2[%f]", chi2));
960 if(!((AliExternalTrackParam&)t).Update(p, cov)) {
962 t.SetStatus(AliTRDtrackV1::kUpdate);
964 UChar_t status(t.GetStatusTRD());
965 AliTRDseedV1 trackletCp(*ptrTracklet);
966 AliTRDtrackV1 trackCp(t);
968 (*cstreamer) << "FollowBackProlongation1"
969 << "status=" << status
970 << "tracklet.=" << &trackletCp
971 << "track.=" << &trackCp
974 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]));
978 if(!kStandAlone) ptrTracklet->UseClusters();
980 AliTracker::FillResiduals(&t, p, cov, ptrTracklet->GetVolumeId());
983 // register tracklet with the tracker and track
984 ptrTracklet->Update(&t);
985 ptrTracklet = SetTracklet(ptrTracklet);
986 Int_t index(fTracklets->GetEntriesFast()-1);
987 t.SetTracklet(ptrTracklet, index);
988 // Register info to track
989 t.SetNumberOfClusters();
992 n += ptrTracklet->GetN();
993 AliDebug(2, Form("Setting Tracklet[%d] @ Idx[%d]", ily, index));
995 // Reset material budget if 2 consecutive gold
996 // if(ilayer>0 && t.GetTracklet(ilayer-1) && ptrTracklet->GetN() + t.GetTracklet(ilayer-1)->GetN() > 20) t.SetBudget(2, 0.);
998 // Make backup of the track until is gold
1000 if(!kStandAlone && (failed = t.MakeBackupTrack())) AliDebug(2, Form("Failed backup on cut[%d]", failed));
1002 } // end layers loop
1003 //printf("clusters[%d] chi2[%f] x[%f] status[%d ", n, t.GetChi2(), t.GetX(), t.GetStatusTRD());
1004 //for(int i=0; i<6; i++) printf("%d ", t.GetStatusTRD(i)); printf("]\n");
1007 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
1008 AliTRDtrackV1 track(t);
1010 (*cstreamer) << "FollowBackProlongation0"
1011 << "EventNumber=" << eventNumber
1013 << "track.=" << &track
1020 //_________________________________________________________________________
1021 Float_t AliTRDtrackerV1::FitRieman(AliTRDseedV1 *tracklets, Double_t *chi2, Int_t *const planes){
1023 // Fits a Riemann-circle to the given points without tilting pad correction.
1024 // The fit is performed using an instance of the class AliRieman (equations
1025 // and transformations see documentation of this class)
1026 // Afterwards all the tracklets are Updated
1028 // Parameters: - Array of tracklets (AliTRDseedV1)
1029 // - Storage for the chi2 values (beginning with direction z)
1030 // - Seeding configuration
1031 // Output: - The curvature
1033 AliRieman *fitter = AliTRDtrackerV1::GetRiemanFitter();
1035 Int_t allplanes[] = {0, 1, 2, 3, 4, 5};
1036 Int_t *ppl = &allplanes[0];
1037 Int_t maxLayers = 6;
1042 for(Int_t il = 0; il < maxLayers; il++){
1043 if(!tracklets[ppl[il]].IsOK()) continue;
1044 fitter->AddPoint(tracklets[ppl[il]].GetX0(), tracklets[ppl[il]].GetYfit(0), tracklets[ppl[il]].GetZfit(0),1,10);
1047 // Set the reference position of the fit and calculate the chi2 values
1048 memset(chi2, 0, sizeof(Double_t) * 2);
1049 for(Int_t il = 0; il < maxLayers; il++){
1050 // Reference positions
1051 tracklets[ppl[il]].Init(fitter);
1054 if((!tracklets[ppl[il]].IsOK()) && (!planes)) continue;
1055 chi2[0] += tracklets[ppl[il]].GetChi2Y();
1056 chi2[1] += tracklets[ppl[il]].GetChi2Z();
1058 return fitter->GetC();
1061 //_________________________________________________________________________
1062 void AliTRDtrackerV1::FitRieman(AliTRDcluster **seedcl, Double_t chi2[2])
1065 // Performs a Riemann helix fit using the seedclusters as spacepoints
1066 // Afterwards the chi2 values are calculated and the seeds are updated
1068 // Parameters: - The four seedclusters
1069 // - The tracklet array (AliTRDseedV1)
1070 // - The seeding configuration
1075 AliRieman *fitter = AliTRDtrackerV1::GetRiemanFitter();
1077 for(Int_t i = 0; i < 4; i++){
1078 fitter->AddPoint(seedcl[i]->GetX(), seedcl[i]->GetY(), seedcl[i]->GetZ(), 1., 10.);
1083 // Update the seed and calculated the chi2 value
1084 chi2[0] = 0; chi2[1] = 0;
1085 for(Int_t ipl = 0; ipl < kNSeedPlanes; ipl++){
1087 chi2[0] += (seedcl[ipl]->GetZ() - fitter->GetZat(seedcl[ipl]->GetX())) * (seedcl[ipl]->GetZ() - fitter->GetZat(seedcl[ipl]->GetX()));
1088 chi2[1] += (seedcl[ipl]->GetY() - fitter->GetYat(seedcl[ipl]->GetX())) * (seedcl[ipl]->GetY() - fitter->GetYat(seedcl[ipl]->GetX()));
1093 //_________________________________________________________________________
1094 Float_t AliTRDtrackerV1::FitTiltedRiemanConstraint(AliTRDseedV1 *tracklets, Double_t zVertex)
1097 // Fits a helix to the clusters. Pad tilting is considered. As constraint it is
1098 // assumed that the vertex position is set to 0.
1099 // This method is very usefull for high-pt particles
1100 // Basis for the fit: (x - x0)^2 + (y - y0)^2 - R^2 = 0
1101 // x0, y0: Center of the circle
1102 // Measured y-position: ymeas = y - tan(phiT)(zc - zt)
1103 // zc: center of the pad row
1104 // Equation which has to be fitted (after transformation):
1105 // a + b * u + e * v + 2*(ymeas + tan(phiT)(z - zVertex))*t = 0
1107 // t = 1/(x^2 + y^2)
1109 // v = 2 * x * tan(phiT) * t
1110 // Parameters in the equation:
1111 // a = -1/y0, b = x0/y0, e = dz/dx
1113 // The Curvature is calculated by the following equation:
1114 // - curv = a/Sqrt(b^2 + 1) = 1/R
1115 // Parameters: - the 6 tracklets
1116 // - the Vertex constraint
1117 // Output: - the Chi2 value of the track
1122 TLinearFitter *fitter = GetTiltedRiemanFitterConstraint();
1123 fitter->StoreData(kTRUE);
1124 fitter->ClearPoints();
1125 AliTRDcluster *cl = NULL;
1127 Float_t x, y, z, w, t, error, tilt;
1130 for(Int_t ilr = 0; ilr < AliTRDgeometry::kNlayer; ilr++){
1131 if(!tracklets[ilr].IsOK()) continue;
1132 for(Int_t itb = 0; itb < AliTRDseedV1::kNclusters; itb++){
1133 if(!tracklets[ilr].IsUsable(itb)) continue;
1134 if(!(cl = tracklets[ilr].GetClusters(itb))) continue;
1135 if(!cl->IsInChamber()) continue;
1139 tilt = tracklets[ilr].GetTilt();
1141 t = 1./(x * x + y * y);
1142 uvt[0] = 2. * x * t;
1143 uvt[1] = 2. * x * t * tilt ;
1144 w = 2. * (y + tilt * (z - zVertex)) * t;
1145 error = 2. * TMath::Sqrt(cl->GetSigmaY2()+tilt*tilt*cl->GetSigmaZ2()) * t;
1146 fitter->AddPoint(uvt, w, error);
1152 // Calculate curvature
1153 Double_t a = fitter->GetParameter(0);
1154 Double_t b = fitter->GetParameter(1);
1155 Double_t curvature = a/TMath::Sqrt(b*b + 1);
1157 Float_t chi2track = fitter->GetChisquare()/Double_t(nPoints);
1158 for(Int_t ip = 0; ip < AliTRDtrackerV1::kNPlanes; ip++)
1159 tracklets[ip].SetC(curvature, 1);
1161 if(AliLog::GetDebugLevel("TRD", "AliTRDtrackerV1")>3) printf("D-AliTRDtrackerV1::FitTiltedRiemanConstraint: Chi2[%f] C[%5.2e] pt[%8.3f]\n", chi2track, curvature, GetBz()*kB2C/curvature);
1163 /* if(fkReconstructor->GetRecoParam()->GetStreamLevel(AliTRDrecoParam::kTracker()) >= 5){
1164 //Linear Model on z-direction
1165 Double_t xref = CalculateReferenceX(tracklets); // Relative to the middle of the stack
1166 Double_t slope = fitter->GetParameter(2);
1167 Double_t zref = slope * xref;
1168 Float_t chi2Z = CalculateChi2Z(tracklets, zref, slope, xref);
1169 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
1170 Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
1171 TTreeSRedirector &treeStreamer = *fkReconstructor->GetDebugStream(AliTRDReconstructor::kTracker);
1172 treeStreamer << "FitTiltedRiemanConstraint"
1173 << "EventNumber=" << eventNumber
1174 << "CandidateNumber=" << candidateNumber
1175 << "Curvature=" << curvature
1176 << "Chi2Track=" << chi2track
1177 << "Chi2Z=" << chi2Z
1184 //_________________________________________________________________________
1185 Float_t AliTRDtrackerV1::FitTiltedRieman(AliTRDseedV1 *tracklets, Bool_t sigError)
1188 // Performs a Riemann fit taking tilting pad correction into account
1189 // The equation of a Riemann circle, where the y position is substituted by the
1190 // measured y-position taking pad tilting into account, has to be transformed
1191 // into a 4-dimensional hyperplane equation
1192 // Riemann circle: (x-x0)^2 + (y-y0)^2 -R^2 = 0
1193 // Measured y-Position: ymeas = y - tan(phiT)(zc - zt)
1194 // zc: center of the pad row
1195 // zt: z-position of the track
1196 // The z-position of the track is assumed to be linear dependent on the x-position
1197 // Transformed equation: a + b * u + c * t + d * v + e * w - 2 * (ymeas + tan(phiT) * zc) * t = 0
1198 // Transformation: u = 2 * x * t
1199 // v = 2 * tan(phiT) * t
1200 // w = 2 * tan(phiT) * (x - xref) * t
1201 // t = 1 / (x^2 + ymeas^2)
1202 // Parameters: a = -1/y0
1204 // c = (R^2 -x0^2 - y0^2)/y0
1207 // If the offset respectively the slope in z-position is impossible, the parameters are fixed using
1208 // results from the simple riemann fit. Afterwards the fit is redone.
1209 // The curvature is calculated according to the formula:
1210 // curv = a/(1 + b^2 + c*a) = 1/R
1212 // Paramters: - Array of tracklets (connected to the track candidate)
1213 // - Flag selecting the error definition
1214 // Output: - Chi2 values of the track (in Parameter list)
1216 TLinearFitter *fitter = GetTiltedRiemanFitter();
1217 fitter->StoreData(kTRUE);
1218 fitter->ClearPoints();
1219 AliTRDLeastSquare zfitter;
1220 AliTRDcluster *cl = NULL;
1222 Double_t xref = CalculateReferenceX(tracklets);
1223 Double_t x, y, z, t, tilt, dx, w, we, erry, errz;
1224 Double_t uvt[4], sumPolY[5], sumPolZ[3];
1225 memset(sumPolY, 0, sizeof(Double_t) * 5);
1226 memset(sumPolZ, 0, sizeof(Double_t) * 3);
1228 // Containers for Least-square fitter
1229 for(Int_t ipl = 0; ipl < kNPlanes; ipl++){
1230 if(!tracklets[ipl].IsOK()) continue;
1231 tilt = tracklets[ipl].GetTilt();
1232 for(Int_t itb = 0; itb < AliTRDseedV1::kNclusters; itb++){
1233 if(!(cl = tracklets[ipl].GetClusters(itb))) continue;
1234 if(!cl->IsInChamber()) continue;
1235 if (!tracklets[ipl].IsUsable(itb)) continue;
1242 uvt[0] = 2. * x * t;
1244 uvt[2] = 2. * tilt * t;
1245 uvt[3] = 2. * tilt * dx * t;
1246 w = 2. * (y + tilt*z) * t;
1247 // error definition changes for the different calls
1249 we *= sigError ? TMath::Sqrt(cl->GetSigmaY2()+tilt*tilt*cl->GetSigmaZ2()) : 0.2;
1250 fitter->AddPoint(uvt, w, we);
1251 zfitter.AddPoint(&x, z, static_cast<Double_t>(TMath::Sqrt(cl->GetSigmaZ2())));
1252 // adding points for covariance matrix estimation
1253 erry = 1./(TMath::Sqrt(cl->GetSigmaY2()) + 0.1); // 0.1 is a systematic error (due to misalignment and miscalibration)
1255 errz = 1./cl->GetSigmaZ2();
1256 for(Int_t ipol = 0; ipol < 5; ipol++){
1257 sumPolY[ipol] += erry;
1260 sumPolZ[ipol] += errz;
1267 if (fitter->Eval()) return 1.e10;
1270 Double_t offset = fitter->GetParameter(3);
1271 Double_t slope = fitter->GetParameter(4);
1273 // Linear fitter - not possible to make boundaries
1274 // Do not accept non possible z and dzdx combinations
1275 Bool_t acceptablez = kTRUE;
1276 Double_t zref = 0.0;
1277 for (Int_t iLayer = 0; iLayer < kNPlanes; iLayer++) {
1278 if(!tracklets[iLayer].IsOK()) continue;
1279 zref = offset + slope * (tracklets[iLayer].GetX0() - xref);
1280 if (TMath::Abs(tracklets[iLayer].GetZfit(0) - zref) > tracklets[iLayer].GetPadLength() * 0.5 + 1.0)
1281 acceptablez = kFALSE;
1284 Double_t dzmf = zfitter.GetFunctionParameter(1);
1285 Double_t zmf = zfitter.GetFunctionValue(&xref);
1286 fgTiltedRieman->FixParameter(3, zmf);
1287 fgTiltedRieman->FixParameter(4, dzmf);
1289 fitter->ReleaseParameter(3);
1290 fitter->ReleaseParameter(4);
1291 offset = fitter->GetParameter(3);
1292 slope = fitter->GetParameter(4);
1295 // Calculate Curvarture
1296 Double_t a = fitter->GetParameter(0);
1297 Double_t b = fitter->GetParameter(1);
1298 Double_t c = fitter->GetParameter(2);
1299 Double_t curvature = 1.0 + b*b - c*a;
1300 if (curvature > 0.0) curvature = a / TMath::Sqrt(curvature);
1302 Double_t chi2track = fitter->GetChisquare()/Double_t(nPoints);
1304 // Prepare error calculation
1305 TMatrixD covarPolY(3,3);
1306 covarPolY(0,0) = sumPolY[0]; covarPolY(1,1) = sumPolY[2]; covarPolY(2,2) = sumPolY[4];
1307 covarPolY(0,1) = covarPolY(1,0) = sumPolY[1];
1308 covarPolY(0,2) = covarPolY(2,0) = sumPolY[2];
1309 covarPolY(2,1) = covarPolY(1,2) = sumPolY[3];
1311 TMatrixD covarPolZ(2,2);
1312 covarPolZ(0,0) = sumPolZ[0]; covarPolZ(1,1) = sumPolZ[2];
1313 covarPolZ(1,0) = covarPolZ(0,1) = sumPolZ[1];
1316 // Update the tracklets
1317 Double_t x1, dy, dz;
1319 memset(cov, 0, sizeof(Double_t) * 15);
1320 for(Int_t iLayer = 0; iLayer < AliTRDtrackerV1::kNPlanes; iLayer++) {
1322 x = tracklets[iLayer].GetX0();
1328 memset(cov, 0, sizeof(Double_t) * 3);
1329 TMatrixD transform(3,3);
1332 transform(0,2) = x*x;
1336 TMatrixD covariance(transform, TMatrixD::kMult, covarPolY);
1337 covariance *= transform.T();
1338 TMatrixD transformZ(2,2);
1339 transformZ(0,0) = transformZ(1,1) = 1;
1340 transformZ(0,1) = x;
1341 TMatrixD covarZ(transformZ, TMatrixD::kMult, covarPolZ);
1342 covarZ *= transformZ.T();
1343 // y: R^2 = (x - x0)^2 + (y - y0)^2
1344 // => y = y0 +/- Sqrt(R^2 - (x - x0)^2)
1345 // R = Sqrt() = 1/Curvature
1346 // => y = y0 +/- Sqrt(1/Curvature^2 - (x - x0)^2)
1347 Double_t res = (x * a + b); // = (x - x0)/y0
1349 res = 1.0 - c * a + b * b - res; // = (R^2 - (x - x0)^2)/y0^2
1351 res = TMath::Sqrt(res);
1352 y = (1.0 - res) / a;
1354 cov[0] = covariance(0,0);
1355 cov[2] = covarZ(0,0);
1358 // dy: R^2 = (x - x0)^2 + (y - y0)^2
1359 // => y = +/- Sqrt(R^2 - (x - x0)^2) + y0
1360 // => dy/dx = (x - x0)/Sqrt(R^2 - (x - x0)^2)
1361 // Curvature: cr = 1/R = a/Sqrt(1 + b^2 - c*a)
1362 // => dy/dx = (x - x0)/(1/(cr^2) - (x - x0)^2)
1363 Double_t x0 = -b / a;
1364 if (-c * a + b * b + 1 > 0) {
1365 if (1.0/(curvature * curvature) - (x - x0) * (x - x0) > 0.0) {
1366 Double_t yderiv = (x - x0) / TMath::Sqrt(1.0/(curvature * curvature) - (x - x0) * (x - x0));
1367 if (a < 0) yderiv *= -1.0;
1371 z = offset + slope * (x - xref);
1373 tracklets[iLayer].SetYref(0, y);
1374 tracklets[iLayer].SetYref(1, dy);
1375 tracklets[iLayer].SetZref(0, z);
1376 tracklets[iLayer].SetZref(1, dz);
1377 tracklets[iLayer].SetC(curvature);
1378 tracklets[iLayer].SetCovRef(cov);
1379 tracklets[iLayer].SetChi2(chi2track);
1381 if(AliLog::GetDebugLevel("TRD", "AliTRDtrackerV1")>3) printf("D-AliTRDtrackerV1::FitTiltedRieman: Chi2[%f] C[%5.2e] pt[%8.3f]\n", chi2track, curvature, GetBz()*kB2C/curvature);
1383 /* if(fkReconstructor->GetRecoParam()->GetStreamLevel(AliTRDrecoParam::kTracker) >=5){
1384 TTreeSRedirector &cstreamer = *fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker);
1385 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
1386 Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
1387 Double_t chi2z = CalculateChi2Z(tracklets, offset, slope, xref);
1388 cstreamer << "FitTiltedRieman0"
1389 << "EventNumber=" << eventNumber
1390 << "CandidateNumber=" << candidateNumber
1392 << "Chi2Z=" << chi2z
1399 //____________________________________________________________________
1400 Double_t AliTRDtrackerV1::FitLine(const AliTRDtrackV1 *track, AliTRDseedV1 *tracklets, Bool_t err, Int_t np, AliTrackPoint *points)
1403 // Fit track with a staight line
1404 // Fills an AliTrackPoint array with np points
1405 // Function should be used to refit tracks when no magnetic field was on
1407 AliTRDLeastSquare yfitter, zfitter;
1408 AliTRDcluster *cl = NULL;
1410 AliTRDseedV1 work[kNPlanes], *tracklet = NULL;
1412 for(Int_t ipl = 0; ipl < kNPlanes; ipl++){
1413 if(!(tracklet = track->GetTracklet(ipl))) continue;
1414 if(!tracklet->IsOK()) continue;
1415 new(&work[ipl]) AliTRDseedV1(*tracklet);
1417 tracklets = &work[0];
1420 Double_t xref = CalculateReferenceX(tracklets);
1421 Double_t x, y, z, dx, ye, yr, tilt;
1422 for(Int_t ipl = 0; ipl < kNPlanes; ipl++){
1423 if(!tracklets[ipl].IsOK()) continue;
1424 for(Int_t itb = 0; itb < fgNTimeBins; itb++){
1425 if(!(cl = tracklets[ipl].GetClusters(itb))) continue;
1426 if (!tracklets[ipl].IsUsable(itb)) continue;
1430 zfitter.AddPoint(&dx, z, static_cast<Double_t>(TMath::Sqrt(cl->GetSigmaZ2())));
1434 Double_t z0 = zfitter.GetFunctionParameter(0);
1435 Double_t dzdx = zfitter.GetFunctionParameter(1);
1436 for(Int_t ipl = 0; ipl < kNPlanes; ipl++){
1437 if(!tracklets[ipl].IsOK()) continue;
1438 for(Int_t itb = 0; itb < fgNTimeBins; itb++){
1439 if(!(cl = tracklets[ipl].GetClusters(itb))) continue;
1440 if (!tracklets[ipl].IsUsable(itb)) continue;
1444 tilt = tracklets[ipl].GetTilt();
1446 yr = y + tilt*(z - z0 - dzdx*dx);
1447 // error definition changes for the different calls
1448 ye = tilt*TMath::Sqrt(cl->GetSigmaZ2());
1449 ye += err ? tracklets[ipl].GetSigmaY() : 0.2;
1450 yfitter.AddPoint(&dx, yr, ye);
1454 Double_t y0 = yfitter.GetFunctionParameter(0);
1455 Double_t dydx = yfitter.GetFunctionParameter(1);
1456 Double_t chi2 = 0.;//yfitter.GetChisquare()/Double_t(nPoints);
1458 //update track points array
1461 for(int ip=0; ip<np; ip++){
1462 points[ip].GetXYZ(xyz);
1463 xyz[1] = y0 + dydx * (xyz[0] - xref);
1464 xyz[2] = z0 + dzdx * (xyz[0] - xref);
1465 points[ip].SetXYZ(xyz);
1472 //_________________________________________________________________________
1473 Double_t AliTRDtrackerV1::FitRiemanTilt(const AliTRDtrackV1 *track, AliTRDseedV1 *tracklets, Bool_t sigError, Int_t np, AliTrackPoint *points)
1476 // Performs a Riemann fit taking tilting pad correction into account
1478 // Paramters: - Array of tracklets (connected to the track candidate)
1479 // - Flag selecting the error definition
1480 // Output: - Chi2 values of the track (in Parameter list)
1482 // The equations which has to be solved simultaneously are:
1484 // R^{2} = (x-x_{0})^{2} + (y^{*}-y_{0})^{2}
1485 // y^{*} = y - tg(h)(z - z_{t})
1486 // z_{t} = z_{0}+dzdx*(x-x_{r})
1488 // with (x, y, z) the coordinate of the cluster, (x_0, y_0, z_0) the coordinate of the center of the Riemann circle,
1489 // R its radius, x_r a constant refrence radial position in the middle of the TRD stack and dzdx the slope of the
1490 // track in the x-z plane. Using the following transformations
1492 // t = 1 / (x^{2} + y^{2})
1494 // v = 2 * tan(h) * t
1495 // w = 2 * tan(h) * (x - x_{r}) * t
1497 // One gets the following linear equation
1499 // a + b * u + c * t + d * v + e * w = 2 * (y + tg(h) * z) * t
1501 // where the coefficients have the following meaning
1505 // c = (R^{2} -x_{0}^{2} - y_{0}^{2})/y_{0}
1509 // The error calculation for the free term is thus
1511 // #sigma = 2 * #sqrt{#sigma^{2}_{y} + (tilt corr ...) + tg^{2}(h) * #sigma^{2}_{z}} * t
1514 // From this simple model one can compute chi^2 estimates and a rough approximation of pt from the curvature according
1517 // C = 1/R = a/(1 + b^{2} + c*a)
1521 // M.Ivanov <M.Ivanov@gsi.de>
1522 // A.Bercuci <A.Bercuci@gsi.de>
1523 // M.Fasel <M.Fasel@gsi.de>
1525 TLinearFitter *fitter = GetTiltedRiemanFitter();
1526 fitter->StoreData(kTRUE);
1527 fitter->ClearPoints();
1528 AliTRDLeastSquare zfitter;
1529 AliTRDcluster *cl = NULL;
1531 AliTRDseedV1 work[kNPlanes], *tracklet = NULL;
1533 for(Int_t ipl = 0; ipl < kNPlanes; ipl++){
1534 if(!(tracklet = track->GetTracklet(ipl))) continue;
1535 if(!tracklet->IsOK()) continue;
1536 new(&work[ipl]) AliTRDseedV1(*tracklet);
1538 tracklets = &work[0];
1541 Double_t xref = CalculateReferenceX(tracklets);
1542 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);
1543 Double_t x, y, z, t, tilt, dx, w, we;
1546 // Containers for Least-square fitter
1547 for(Int_t ipl = 0; ipl < kNPlanes; ipl++){
1548 if(!tracklets[ipl].IsOK()) continue;
1549 for(Int_t itb = 0; itb < AliTRDseedV1::kNclusters; itb++){
1550 if(!(cl = tracklets[ipl].GetClusters(itb))) continue;
1551 //if (!tracklets[ipl].IsUsable(itb)) continue;
1555 tilt = tracklets[ipl].GetTilt();
1559 uvt[0] = 2. * x * t;
1561 uvt[2] = 2. * tilt * t;
1562 uvt[3] = 2. * tilt * dx * t;
1563 w = 2. * (y + tilt*z) * t;
1564 // error definition changes for the different calls
1566 we *= sigError ? TMath::Sqrt(cl->GetSigmaY2()) : 0.2;
1567 fitter->AddPoint(uvt, w, we);
1568 zfitter.AddPoint(&x, z, static_cast<Double_t>(TMath::Sqrt(cl->GetSigmaZ2())));
1572 if(fitter->Eval()) return 1.E10;
1574 Double_t z0 = fitter->GetParameter(3);
1575 Double_t dzdx = fitter->GetParameter(4);
1578 // Linear fitter - not possible to make boundaries
1579 // Do not accept non possible z and dzdx combinations
1580 Bool_t accept = kTRUE;
1581 Double_t zref = 0.0;
1582 for (Int_t iLayer = 0; iLayer < kNPlanes; iLayer++) {
1583 if(!tracklets[iLayer].IsOK()) continue;
1584 zref = z0 + dzdx * (tracklets[iLayer].GetX0() - xref);
1585 if (TMath::Abs(tracklets[iLayer].GetZfit(0) - zref) > tracklets[iLayer].GetPadLength() * 0.5 + 1.0)
1590 Double_t dzmf = zfitter.GetFunctionParameter(1);
1591 Double_t zmf = zfitter.GetFunctionValue(&xref);
1592 fitter->FixParameter(3, zmf);
1593 fitter->FixParameter(4, dzmf);
1595 fitter->ReleaseParameter(3);
1596 fitter->ReleaseParameter(4);
1597 z0 = fitter->GetParameter(3); // = zmf ?
1598 dzdx = fitter->GetParameter(4); // = dzmf ?
1601 // Calculate Curvature
1602 Double_t a = fitter->GetParameter(0);
1603 Double_t b = fitter->GetParameter(1);
1604 Double_t c = fitter->GetParameter(2);
1605 Double_t y0 = 1. / a;
1606 Double_t x0 = -b * y0;
1607 Double_t tmp = y0*y0 + x0*x0 - c*y0;
1608 if(tmp<=0.) return 1.E10;
1609 Double_t radius = TMath::Sqrt(tmp);
1610 Double_t curvature = 1.0 + b*b - c*a;
1611 if (curvature > 0.0) curvature = a / TMath::Sqrt(curvature);
1613 // Calculate chi2 of the fit
1614 Double_t chi2 = fitter->GetChisquare()/Double_t(nPoints);
1615 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);
1617 // Update the tracklets
1619 for(Int_t ip = 0; ip < kNPlanes; ip++) {
1620 x = tracklets[ip].GetX0();
1621 tmp = radius*radius-(x-x0)*(x-x0);
1622 if(tmp <= 0.) continue;
1623 tmp = TMath::Sqrt(tmp);
1625 // y: R^2 = (x - x0)^2 + (y - y0)^2
1626 // => y = y0 +/- Sqrt(R^2 - (x - x0)^2)
1627 tracklets[ip].SetYref(0, y0 - (y0>0.?1.:-1)*tmp);
1628 // => dy/dx = (x - x0)/Sqrt(R^2 - (x - x0)^2)
1629 tracklets[ip].SetYref(1, (x - x0) / tmp);
1630 tracklets[ip].SetZref(0, z0 + dzdx * (x - xref));
1631 tracklets[ip].SetZref(1, dzdx);
1632 tracklets[ip].SetC(curvature);
1633 tracklets[ip].SetChi2(chi2);
1636 //update track points array
1639 for(int ip=0; ip<np; ip++){
1640 points[ip].GetXYZ(xyz);
1641 xyz[1] = TMath::Abs(xyz[0] - x0) > radius ? 100. : y0 - (y0>0.?1.:-1.)*TMath::Sqrt((radius-(xyz[0]-x0))*(radius+(xyz[0]-x0)));
1642 xyz[2] = z0 + dzdx * (xyz[0] - xref);
1643 points[ip].SetXYZ(xyz);
1651 //____________________________________________________________________
1652 Double_t AliTRDtrackerV1::FitKalman(AliTRDtrackV1 *track, AliTRDseedV1 * const tracklets, Bool_t up, Int_t np, AliTrackPoint *points)
1654 // Kalman filter implementation for the TRD.
1655 // It returns the positions of the fit in the array "points"
1657 // Author : A.Bercuci@gsi.de
1659 // printf("Start track @ x[%f]\n", track->GetX());
1661 //prepare marker points along the track
1662 Int_t ip = np ? 0 : 1;
1664 if((up?-1:1) * (track->GetX() - points[ip].GetX()) > 0.) break;
1665 //printf("AliTRDtrackerV1::FitKalman() : Skip track marker x[%d] = %7.3f. Before track start ( %7.3f ).\n", ip, points[ip].GetX(), track->GetX());
1668 //if(points) printf("First marker point @ x[%d] = %f\n", ip, points[ip].GetX());
1671 AliTRDseedV1 tracklet;
1672 AliTRDseedV1 *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) - AliTRDReconstructor::GetMaxStep() < 0) break;
1696 if(((up?-1:1) * (points[ip].GetX() - track->GetX()) < 0) && !PropagateToX(*track, points[ip].GetX(), AliTRDReconstructor::GetMaxStep())) 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()) + AliTRDReconstructor::GetMaxStep() < 0) && !PropagateToX(*track, x + (up?-1:1)*AliTRDReconstructor::GetMaxStep(), AliTRDReconstructor::GetMaxStep())) return -1.;
1709 if(!AdjustSector(track)) return -1;
1710 if(TMath::Abs(track->GetSnp()) > AliTRDReconstructor::GetMaxSnp()) 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) ((AliExternalTrackParam*)track)->Update(p, cov);
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(), AliTRDReconstructor::GetMaxStep())) 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(const 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 // Current track X-position
1805 Double_t xpos = t.GetX();
1807 // Direction: inward or outward
1808 Double_t dir = (xpos < xToGo) ? 1.0 : -1.0;
1810 while (((xToGo - xpos) * dir) > AliTRDReconstructor::GetEpsilon()) {
1819 // The next step size
1820 Double_t step = dir * TMath::Min(TMath::Abs(xToGo-xpos),maxStep);
1822 // Get the global position of the starting point
1825 // X-position after next step
1828 // Get local Y and Z at the X-position of the next step
1829 if(t.GetProlongation(x,y,z)<0) return 0; // No prolongation possible
1831 // The global position of the end point of this prolongation step
1832 xyz1[0] = x * TMath::Cos(t.GetAlpha()) - y * TMath::Sin(t.GetAlpha());
1833 xyz1[1] = +x * TMath::Sin(t.GetAlpha()) + y * TMath::Cos(t.GetAlpha());
1836 // Calculate the mean material budget between start and
1837 // end point of this prolongation step
1838 if(AliTracker::MeanMaterialBudget(xyz0, xyz1, param)<=0.) return 0;
1840 // Propagate the track to the X-position after the next step
1841 if (!t.PropagateTo(x, param[1], param[0]*param[4])) return 0;
1843 // Rotate the track if necessary
1844 if(!AdjustSector(&t)) return 0;
1846 // New track X-position
1856 //_____________________________________________________________________________
1857 Bool_t AliTRDtrackerV1::ReadClusters(TTree *clusterTree)
1860 // Reads AliTRDclusters from the file.
1861 // The names of the cluster tree and branches
1862 // should match the ones used in AliTRDclusterizer::WriteClusters()
1865 Int_t nsize = Int_t(clusterTree->GetTotBytes() / (sizeof(AliTRDcluster)));
1866 TObjArray *clusterArray = new TObjArray(nsize+1000);
1868 TBranch *branch = clusterTree->GetBranch("TRDcluster");
1870 AliError("Can't get the branch !");
1873 branch->SetAddress(&clusterArray);
1876 Float_t nclusters = fkRecoParam->GetNClusters();
1877 if(fkReconstructor->IsHLT()) nclusters /= AliTRDgeometry::kNsector;
1878 fClusters = new TClonesArray("AliTRDcluster", Int_t(nclusters));
1879 fClusters->SetOwner(kTRUE);
1882 // Loop through all entries in the tree
1883 Int_t nEntries = (Int_t) clusterTree->GetEntries();
1886 AliTRDcluster *c = NULL;
1887 for (Int_t iEntry = 0; iEntry < nEntries; iEntry++) {
1889 nbytes += clusterTree->GetEvent(iEntry);
1891 // Get the number of points in the detector
1892 Int_t nCluster = clusterArray->GetEntriesFast();
1893 for (Int_t iCluster = 0; iCluster < nCluster; iCluster++) {
1894 if(!(c = (AliTRDcluster *) clusterArray->UncheckedAt(iCluster))) continue;
1895 new((*fClusters)[ncl++]) AliTRDcluster(*c);
1896 delete (clusterArray->RemoveAt(iCluster));
1899 delete clusterArray;
1904 //_____________________________________________________________________________
1905 Int_t AliTRDtrackerV1::LoadClusters(TTree *cTree)
1908 // Fills clusters into TRD tracking sectors
1911 fkRecoParam = fkReconstructor->GetRecoParam(); // load reco param for this event
1913 if(!fkReconstructor->IsWritingClusters()){
1914 fClusters = AliTRDReconstructor::GetClusters();
1916 if(!ReadClusters(cTree)) {
1917 AliError("Problem with reading the clusters !");
1923 if(!fClusters || !fClusters->GetEntriesFast()){
1924 AliInfo("No TRD clusters");
1929 BuildTrackingContainers();
1931 //Int_t ncl = fClusters->GetEntriesFast();
1932 //AliInfo(Form("Clusters %d [%6.2f %% in the active volume]", ncl, 100.*float(nin)/ncl));
1937 //_____________________________________________________________________________
1938 Int_t AliTRDtrackerV1::LoadClusters(TClonesArray * const clusters)
1941 // Fills clusters into TRD tracking sectors
1942 // Function for use in the HLT
1944 if(!clusters || !clusters->GetEntriesFast()){
1945 AliInfo("No TRD clusters");
1949 fClusters = clusters;
1952 fkRecoParam = fkReconstructor->GetRecoParam(); // load reco param for this event
1953 BuildTrackingContainers();
1955 //Int_t ncl = fClusters->GetEntriesFast();
1956 //AliInfo(Form("Clusters %d [%6.2f %% in the active volume]", ncl, 100.*float(nin)/ncl));
1962 //____________________________________________________________________
1963 Int_t AliTRDtrackerV1::BuildTrackingContainers()
1965 // Building tracking containers for clusters
1967 Int_t nin(0), ncl(fClusters->GetEntriesFast());
1969 AliTRDcluster *c = (AliTRDcluster *) fClusters->UncheckedAt(ncl);
1970 if(c->IsInChamber()) nin++;
1971 if(fkReconstructor->IsHLT()) c->SetRPhiMethod(AliTRDcluster::kCOG);
1972 Int_t detector = c->GetDetector();
1973 Int_t sector = fGeom->GetSector(detector);
1974 Int_t stack = fGeom->GetStack(detector);
1975 Int_t layer = fGeom->GetLayer(detector);
1977 fTrSec[sector].GetChamber(stack, layer, kTRUE)->InsertCluster(c, ncl);
1980 for(int isector =0; isector<AliTRDgeometry::kNsector; isector++){
1981 if(!fTrSec[isector].GetNChambers()) continue;
1982 fTrSec[isector].Init(fkReconstructor);
1990 //____________________________________________________________________
1991 void AliTRDtrackerV1::UnloadClusters()
1994 // Clears the arrays of clusters and tracks. Resets sectors and timebins
1995 // If option "force" is also set the containers are also deleted. This is useful
2000 if(HasRemoveContainers()){delete fTracks; fTracks = NULL;}
2003 fTracklets->Delete();
2004 if(HasRemoveContainers()){delete fTracklets; fTracklets = NULL;}
2007 if(IsClustersOwner()) fClusters->Delete();
2009 // save clusters array in the reconstructor for further use.
2010 if(!fkReconstructor->IsWritingClusters()){
2011 AliTRDReconstructor::SetClusters(fClusters);
2012 SetClustersOwner(kFALSE);
2013 } else AliTRDReconstructor::SetClusters(NULL);
2016 for (int i = 0; i < AliTRDgeometry::kNsector; i++) fTrSec[i].Clear();
2018 // Increment the Event Number
2019 AliTRDtrackerDebug::SetEventNumber(AliTRDtrackerDebug::GetEventNumber() + 1);
2022 // //____________________________________________________________________
2023 // void AliTRDtrackerV1::UseClusters(const AliKalmanTrack *t, Int_t) const
2025 // const AliTRDtrackV1 *track = dynamic_cast<const AliTRDtrackV1*>(t);
2026 // if(!track) return;
2028 // AliTRDseedV1 *tracklet = NULL;
2029 // for(Int_t ily=AliTRDgeometry::kNlayer; ily--;){
2030 // if(!(tracklet = track->GetTracklet(ily))) continue;
2031 // AliTRDcluster *c = NULL;
2032 // for(Int_t ic=AliTRDseed::kNclusters; ic--;){
2033 // if(!(c=tracklet->GetClusters(ic))) continue;
2040 //_____________________________________________________________________________
2041 Bool_t AliTRDtrackerV1::AdjustSector(AliTRDtrackV1 *const track)
2044 // Rotates the track when necessary
2047 Double_t alpha = AliTRDgeometry::GetAlpha();
2048 Double_t y = track->GetY();
2049 Double_t ymax = track->GetX()*TMath::Tan(0.5*alpha);
2052 if (!track->Rotate( alpha)) {
2056 else if (y < -ymax) {
2057 if (!track->Rotate(-alpha)) {
2067 //____________________________________________________________________
2068 AliTRDseedV1* AliTRDtrackerV1::GetTracklet(AliTRDtrackV1 *const track, Int_t p, Int_t &idx)
2070 // Find tracklet for TRD track <track>
2079 // Detailed description
2081 idx = track->GetTrackletIndex(p);
2082 AliTRDseedV1 *tracklet = (idx<0) ? NULL : (AliTRDseedV1*)fTracklets->UncheckedAt(idx);
2087 //____________________________________________________________________
2088 AliTRDseedV1* AliTRDtrackerV1::SetTracklet(const AliTRDseedV1 * const tracklet)
2090 // Add this tracklet to the list of tracklets stored in the tracker
2093 // - tracklet : pointer to the tracklet to be added to the list
2096 // - the index of the new tracklet in the tracker tracklets list
2098 // Detailed description
2099 // Build the tracklets list if it is not yet created (late initialization)
2100 // and adds the new tracklet to the list.
2103 fTracklets = new TClonesArray("AliTRDseedV1", AliTRDgeometry::Nsector()*kMaxTracksStack);
2104 fTracklets->SetOwner(kTRUE);
2106 Int_t nentries = fTracklets->GetEntriesFast();
2107 return new ((*fTracklets)[nentries]) AliTRDseedV1(*tracklet);
2110 //____________________________________________________________________
2111 AliTRDtrackV1* AliTRDtrackerV1::SetTrack(const AliTRDtrackV1 * const track)
2113 // Add this track to the list of tracks stored in the tracker
2116 // - track : pointer to the track to be added to the list
2119 // - the pointer added
2121 // Detailed description
2122 // Build the tracks list if it is not yet created (late initialization)
2123 // and adds the new track to the list.
2126 fTracks = new TClonesArray("AliTRDtrackV1", AliTRDgeometry::Nsector()*kMaxTracksStack);
2127 fTracks->SetOwner(kTRUE);
2129 Int_t nentries = fTracks->GetEntriesFast();
2130 return new ((*fTracks)[nentries]) AliTRDtrackV1(*track);
2135 //____________________________________________________________________
2136 Int_t AliTRDtrackerV1::Clusters2TracksSM(Int_t sector, AliESDEvent *esd)
2139 // Steer tracking for one SM.
2142 // sector : Array of (SM) propagation layers containing clusters
2143 // esd : The current ESD event. On output it contains the also
2144 // the ESD (TRD) tracks found in this SM.
2147 // Number of tracks found in this TRD supermodule.
2149 // Detailed description
2151 // 1. Unpack AliTRDpropagationLayers objects for each stack.
2152 // 2. Launch stack tracking.
2153 // See AliTRDtrackerV1::Clusters2TracksStack() for details.
2154 // 3. Pack results in the ESD event.
2158 Int_t nChambers = 0;
2159 AliTRDtrackingChamber **stack = NULL, *chamber = NULL;
2160 for(int istack = 0; istack<AliTRDgeometry::kNstack; istack++){
2161 if(!(stack = fTrSec[sector].GetStack(istack))) continue;
2163 for(int ilayer=0; ilayer<AliTRDgeometry::kNlayer; ilayer++){
2164 if(!(chamber = stack[ilayer])) continue;
2165 if(chamber->GetNClusters() < fgNTimeBins * fkRecoParam->GetFindableClusters()) continue;
2167 //AliInfo(Form("sector %d stack %d layer %d clusters %d", sector, istack, ilayer, chamber->GetNClusters()));
2169 if(nChambers < 4) continue;
2170 //AliInfo(Form("Doing stack %d", istack));
2171 nTracks += Clusters2TracksStack(stack, fTracksESD);
2173 if(nTracks) AliDebug(2, Form("Number of tracks: SM_%02d[%d]", sector, nTracks));
2175 for(int itrack=0; itrack<nTracks; itrack++){
2176 AliESDtrack *esdTrack((AliESDtrack*)(fTracksESD->operator[](itrack)));
2177 Int_t id = esd->AddTrack(esdTrack);
2179 // set ESD id to stand alone TRD tracks
2180 if (fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) > 0){
2181 esdTrack=esd->GetTrack(id);
2182 TObject *o(NULL); Int_t ic(0);
2183 AliTRDtrackV1 *calibTrack(NULL);
2184 while((o = esdTrack->GetCalibObject(ic++))){
2185 if(!(calibTrack = dynamic_cast<AliTRDtrackV1*>(o))) continue;
2186 calibTrack->SetESDid(esdTrack->GetID());
2192 // Reset Track and Candidate Number
2193 AliTRDtrackerDebug::SetCandidateNumber(0);
2194 AliTRDtrackerDebug::SetTrackNumber(0);
2196 // delete ESD tracks in the array
2197 fTracksESD->Delete();
2201 //____________________________________________________________________
2202 Int_t AliTRDtrackerV1::Clusters2TracksStack(AliTRDtrackingChamber **stack, TClonesArray * const esdTrackList)
2205 // Make tracks in one TRD stack.
2208 // layer : Array of stack propagation layers containing clusters
2209 // esdTrackList : Array of ESD tracks found by the stand alone tracker.
2210 // On exit the tracks found in this stack are appended.
2213 // Number of tracks found in this stack.
2215 // Detailed description
2217 // 1. Find the 3 most useful seeding chambers. See BuildSeedingConfigs() for details.
2218 // 2. Steer AliTRDtrackerV1::MakeSeeds() for 3 seeding layer configurations.
2219 // See AliTRDtrackerV1::MakeSeeds() for more details.
2220 // 3. Arrange track candidates in decreasing order of their quality
2221 // 4. Classify tracks in 5 categories according to:
2222 // a) number of layers crossed
2224 // 5. Sign clusters by tracks in decreasing order of track quality
2225 // 6. Build AliTRDtrack out of seeding tracklets
2227 // 8. Build ESD track and register it to the output list
2230 AliTRDtrackingChamber *chamber = NULL;
2231 AliTRDtrackingChamber **ci = NULL;
2232 AliTRDseedV1 sseed[kMaxTracksStack*6]; // to be initialized
2233 Int_t pars[4]; // MakeSeeds parameters
2235 //Double_t alpha = AliTRDgeometry::GetAlpha();
2236 //Double_t shift = .5 * alpha;
2237 Int_t configs[kNConfigs];
2239 // Purge used clusters from the containers
2241 for(Int_t ic = kNPlanes; ic--; ci++){
2242 if(!(*ci)) continue;
2246 // Build initial seeding configurations
2247 Double_t quality = BuildSeedingConfigs(stack, configs);
2248 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) > 10){
2249 AliInfo(Form("Plane config %d %d %d Quality %f"
2250 , configs[0], configs[1], configs[2], quality));
2254 // Initialize contors
2255 Int_t ntracks, // number of TRD track candidates
2256 ntracks1, // number of registered TRD tracks/iter
2257 ntracks2 = 0; // number of all registered TRD tracks in stack
2261 Int_t ic = 0; ci = &stack[0];
2262 while(ic<kNPlanes && !(*ci)){ic++; ci++;}
2263 if(!(*ci)) return ntracks2;
2264 Int_t istack = fGeom->GetStack((*ci)->GetDetector());
2267 // Loop over seeding configurations
2268 ntracks = 0; ntracks1 = 0;
2269 for (Int_t iconf = 0; iconf<fkRecoParam->GetNumberOfSeedConfigs(); iconf++) {
2270 pars[0] = configs[iconf];
2273 ntracks = MakeSeeds(stack, &sseed[6*ntracks], pars);
2274 //AliInfo(Form("Number of Tracks after iteration step %d: %d\n", iconf, ntracks));
2275 if(ntracks == kMaxTracksStack) break;
2277 AliDebug(2, Form("Candidate TRD tracks %d in iteration %d.", ntracks, fSieveSeeding));
2280 // Sort the seeds according to their quality
2281 Int_t sort[kMaxTracksStack+1];
2282 TMath::Sort(ntracks, fTrackQuality, sort, kTRUE);
2283 if(AliLog::GetDebugLevel("TRD", "AliTRDtrackerV1") > 2){
2284 AliDebug(3, "Track candidates classification:");
2285 for (Int_t it(0); it < ntracks; it++) {
2287 printf(" %2d idx[%d] Quality[%e]\n", it, jt, fTrackQuality[jt]);
2291 // Initialize number of tracks so far and logic switches
2292 Int_t ntracks0 = esdTrackList->GetEntriesFast();
2293 Bool_t signedTrack[kMaxTracksStack];
2294 Bool_t fakeTrack[kMaxTracksStack];
2295 for (Int_t i=0; i<ntracks; i++){
2296 signedTrack[i] = kFALSE;
2297 fakeTrack[i] = kFALSE;
2299 //AliInfo("Selecting track candidates ...");
2301 // Sieve clusters in decreasing order of track quality
2302 Int_t jSieve(0), rejectedCandidates(0);
2304 // Check track candidates
2305 rejectedCandidates=0;
2306 for (Int_t itrack = 0; itrack < ntracks; itrack++) {
2307 Int_t trackIndex = sort[itrack];
2308 if (signedTrack[trackIndex] || fakeTrack[trackIndex]) continue;
2310 // Calculate track parameters from tracklets seeds
2315 for (Int_t jLayer = 0; jLayer < kNPlanes; jLayer++) {
2316 Int_t jseed = kNPlanes*trackIndex+jLayer;
2317 sseed[jseed].UpdateUsed();
2318 if(!sseed[jseed].IsOK()) continue;
2319 // check if primary candidate
2320 if (TMath::Abs(sseed[jseed].GetYref(0) / sseed[jseed].GetX0()) < 0.158) findable++;
2321 ncl += sseed[jseed].GetN();
2322 nused += sseed[jseed].GetNUsed();
2326 // Filter duplicated tracks
2328 AliDebug(4, Form("REJECTED : %d idx[%d] quality[%e] tracklets[%d] usedClusters[%d]", itrack, trackIndex, fTrackQuality[trackIndex], nlayers, nused));
2329 fakeTrack[trackIndex] = kTRUE;
2332 if (ncl>0 && Float_t(nused)/ncl >= .25){
2333 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));
2334 fakeTrack[trackIndex] = kTRUE;
2338 AliDebug(4, Form("Candidate[%d] Quality[%e] Tracklets[%d] Findable[%d] Ncl[%d] Nused[%d]", trackIndex, fTrackQuality[trackIndex], nlayers, findable, ncl, nused));
2341 Bool_t skip = kFALSE;
2343 case 0: // select 6 tracklets primary tracks, good quality
2344 if(nlayers > findable || nlayers < kNPlanes) {skip = kTRUE; break;}
2345 if(TMath::Log(1.E-9+fTrackQuality[trackIndex]) < -5.){skip = kTRUE; break;}
2348 case 1: // select shorter primary tracks, good quality
2349 //if(findable<4){skip = kTRUE; break;}
2350 if(nlayers < findable){skip = kTRUE; break;}
2351 if(TMath::Log(1.E-9+fTrackQuality[trackIndex]) < -4.){skip = kTRUE; break;}
2354 case 2: // select 6 tracklets secondary tracks
2355 if(nlayers < kNPlanes) { skip = kTRUE; break;}
2356 if (TMath::Log(1.E-9+fTrackQuality[trackIndex]) < -6.0){skip = kTRUE; break;}
2359 case 3: // select shorter tracks, good quality
2360 if (nlayers<4){skip = kTRUE; break;}
2361 if (TMath::Log(1.E-9+fTrackQuality[trackIndex]) < -5.){skip = kTRUE; break;}
2364 case 4: // select anything with at least 4 tracklets
2365 if (nlayers<4){skip = kTRUE; break;}
2366 //if (TMath::Log(1.E-9+fTrackQuality[trackIndex]) - nused/(nlayers-3.0) < -15.0){skip = kTRUE; break;}
2370 rejectedCandidates++;
2371 AliDebug(4, Form("REJECTED : %d idx[%d] quality[%e] tracklets[%d] usedClusters[%d]", itrack, trackIndex, fTrackQuality[trackIndex], nlayers, nused));
2373 } else AliDebug(4, Form("ACCEPTED : %d idx[%d] quality[%e] tracklets[%d] usedClusters[%d]", itrack, trackIndex, fTrackQuality[trackIndex], nlayers, nused));
2375 signedTrack[trackIndex] = kTRUE;
2377 AliTRDseedV1 *lseed =&sseed[trackIndex*kNPlanes];
2378 AliTRDtrackV1 *track = MakeTrack(lseed);
2380 AliDebug(1, "Track building failed.");
2383 if(AliLog::GetDebugLevel("TRD", "AliTRDtrackerV1") > 1){
2384 Int_t ich = 0; while(!(chamber = stack[ich])) ich++;
2385 AliDebug(2, Form("Track pt=%7.2fGeV/c SM[%2d] Done.", track->Pt(), fGeom->GetSector(chamber->GetDetector())));
2389 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) > 1 && fkReconstructor->IsDebugStreaming()){
2390 //AliInfo(Form("Track %d [%d] nlayers %d trackQuality = %e nused %d, yref = %3.3f", itrack, trackIndex, nlayers, fTrackQuality[trackIndex], nused, trackParams[1]));
2392 AliTRDseedV1 *dseed[6];
2393 for(Int_t iseed = AliTRDgeometry::kNlayer; iseed--;) dseed[iseed] = new AliTRDseedV1(lseed[iseed]);
2395 //Int_t eventNrInFile = esd->GetEventNumberInFile();
2396 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
2397 Int_t trackNumber = AliTRDtrackerDebug::GetTrackNumber();
2398 Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
2399 TTreeSRedirector &cstreamer = *fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker);
2400 cstreamer << "Clusters2TracksStack"
2401 << "EventNumber=" << eventNumber
2402 << "TrackNumber=" << trackNumber
2403 << "CandidateNumber=" << candidateNumber
2404 << "Iter=" << fSieveSeeding
2405 << "Like=" << fTrackQuality[trackIndex]
2406 << "S0.=" << dseed[0]
2407 << "S1.=" << dseed[1]
2408 << "S2.=" << dseed[2]
2409 << "S3.=" << dseed[3]
2410 << "S4.=" << dseed[4]
2411 << "S5.=" << dseed[5]
2413 << "NLayers=" << nlayers
2414 << "Findable=" << findable
2415 << "NUsed=" << nused
2420 AliESDtrack *esdTrack = new ((*esdTrackList)[ntracks0++]) AliESDtrack();
2421 esdTrack->UpdateTrackParams(track, AliESDtrack::kTRDout);
2422 esdTrack->SetLabel(track->GetLabel());
2423 track->UpdateESDtrack(esdTrack);
2424 // write ESD-friends if neccessary
2425 if (fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) > 0){
2426 AliTRDtrackV1 *calibTrack = new AliTRDtrackV1(*track);
2427 calibTrack->SetOwner();
2428 esdTrack->AddCalibObject(calibTrack);
2431 AliTRDtrackerDebug::SetTrackNumber(AliTRDtrackerDebug::GetTrackNumber() + 1);
2435 } while(jSieve<5 && rejectedCandidates); // end track candidates sieve
2436 if(!ntracks1) break;
2438 // increment counters
2439 ntracks2 += ntracks1;
2441 if(fkReconstructor->IsHLT()) break;
2444 // Rebuild plane configurations and indices taking only unused clusters into account
2445 quality = BuildSeedingConfigs(stack, configs);
2446 if(quality < 1.E-7) break; //fkReconstructor->GetRecoParam() ->GetPlaneQualityThreshold()) break;
2448 for(Int_t ip = 0; ip < kNPlanes; ip++){
2449 if(!(chamber = stack[ip])) continue;
2450 chamber->Build(fGeom);//Indices(fSieveSeeding);
2453 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) > 10){
2454 AliInfo(Form("Sieve level %d Plane config %d %d %d Quality %f", fSieveSeeding, configs[0], configs[1], configs[2], quality));
2456 } while(fSieveSeeding<10); // end stack clusters sieve
2460 //AliInfo(Form("Registered TRD tracks %d in stack %d.", ntracks2, pars[1]));
2465 //___________________________________________________________________
2466 Double_t AliTRDtrackerV1::BuildSeedingConfigs(AliTRDtrackingChamber **stack, Int_t *configs)
2469 // Assign probabilities to chambers according to their
2470 // capability of producing seeds.
2474 // layers : Array of stack propagation layers for all 6 chambers in one stack
2475 // configs : On exit array of configuration indexes (see GetSeedingConfig()
2476 // for details) in the decreasing order of their seeding probabilities.
2480 // Return top configuration quality
2482 // Detailed description:
2484 // To each chamber seeding configuration (see GetSeedingConfig() for
2485 // the list of all configurations) one defines 2 quality factors:
2486 // - an apriori topological quality (see GetSeedingConfig() for details) and
2487 // - a data quality based on the uniformity of the distribution of
2488 // clusters over the x range (time bins population). See CookChamberQA() for details.
2489 // The overall chamber quality is given by the product of this 2 contributions.
2492 Double_t chamberQ[kNPlanes];memset(chamberQ, 0, kNPlanes*sizeof(Double_t));
2493 AliTRDtrackingChamber *chamber = NULL;
2494 for(int iplane=0; iplane<kNPlanes; iplane++){
2495 if(!(chamber = stack[iplane])) continue;
2496 chamberQ[iplane] = (chamber = stack[iplane]) ? chamber->GetQuality() : 0.;
2499 Double_t tconfig[kNConfigs];memset(tconfig, 0, kNConfigs*sizeof(Double_t));
2500 Int_t planes[] = {0, 0, 0, 0};
2501 for(int iconf=0; iconf<kNConfigs; iconf++){
2502 GetSeedingConfig(iconf, planes);
2503 tconfig[iconf] = fgTopologicQA[iconf];
2504 for(int iplane=0; iplane<4; iplane++) tconfig[iconf] *= chamberQ[planes[iplane]];
2507 TMath::Sort((Int_t)kNConfigs, tconfig, configs, kTRUE);
2508 // AliInfo(Form("q[%d] = %f", configs[0], tconfig[configs[0]]));
2509 // AliInfo(Form("q[%d] = %f", configs[1], tconfig[configs[1]]));
2510 // AliInfo(Form("q[%d] = %f", configs[2], tconfig[configs[2]]));
2512 return tconfig[configs[0]];
2515 //____________________________________________________________________
2516 Int_t AliTRDtrackerV1::MakeSeeds(AliTRDtrackingChamber **stack, AliTRDseedV1 * const sseed, const Int_t * const ipar)
2519 // Seed tracklets and build candidate TRD tracks. The procedure is used during barrel tracking to account for tracks which are
2520 // either missed by TPC prolongation or conversions inside the TRD volume.
2521 // For stand alone tracking the procedure is used to estimate all tracks measured by TRD.
2524 // layers : Array of stack propagation layers containing clusters
2525 // sseed : Array of empty tracklet seeds. On exit they are filled.
2526 // ipar : Control parameters:
2527 // ipar[0] -> seeding chambers configuration
2528 // ipar[1] -> stack index
2529 // ipar[2] -> number of track candidates found so far
2532 // Number of tracks candidates found.
2534 // The following steps are performed:
2535 // 1. Build seeding layers by collapsing all time bins from each of the four seeding chambers along the
2536 // radial coordinate. See AliTRDtrackingChamber::GetSeedingLayer() for details. The chambers selection for seeding
2537 // is described in AliTRDtrackerV1::Clusters2TracksStack().
2538 // 2. Using the seeding clusters from the seeding layer (step 1) build combinatorics using the following algorithm:
2539 // - for each seeding cluster in the lower seeding layer find
2540 // - all seeding clusters in the upper seeding layer inside a road defined by a given phi angle. The angle
2541 // is calculated on the minimum pt of tracks from vertex accesible to the stand alone tracker.
2542 // - for each pair of two extreme seeding clusters select middle upper cluster using roads defined externally by the
2544 // - select last seeding cluster as the nearest to the linear approximation of the track described by the first three
2545 // seeding clusters.
2546 // The implementation of road calculation and cluster selection can be found in the functions AliTRDchamberTimeBin::BuildCond()
2547 // and AliTRDchamberTimeBin::GetClusters().
2548 // 3. Helix fit of the seeding clusters set. (see AliTRDtrackerFitter::FitRieman(AliTRDcluster**)). No tilt correction is
2549 // performed at this level
2550 // 4. Initialize seeding tracklets in the seeding chambers.
2551 // 5. *Filter 0* Chi2 cut on the Y and Z directions. The threshold is set externally by the reco params.
2552 // 6. Attach (true) clusters to seeding tracklets (see AliTRDseedV1::AttachClusters()) and fit tracklet (see
2553 // AliTRDseedV1::Fit()). The number of used clusters used by current seeds should not exceed ... (25).
2554 // 7. *Filter 1* Check if all 4 seeding tracklets are correctly constructed.
2555 // 8. Helix fit of the clusters from the seeding tracklets with tilt correction. Refit tracklets using the new
2556 // approximation of the track.
2557 // 9. *Filter 2* Calculate likelihood of the track. (See AliTRDtrackerV1::CookLikelihood()). The following quantities are
2558 // checked against the Riemann fit:
2559 // - position resolution in y
2560 // - angular resolution in the bending plane
2561 // - likelihood of the number of clusters attached to the tracklet
2562 // 10. Extrapolation of the helix fit to the other 2 chambers *non seeding* chambers:
2563 // - Initialization of extrapolation tracklets with the fit parameters
2564 // - Attach clusters to extrapolated tracklets
2565 // - Helix fit of tracklets
2566 // 11. Improve seeding tracklets quality by reassigning clusters based on the last parameters of the track
2567 // See AliTRDtrackerV1::ImproveSeedQuality() for details.
2568 // 12. Helix fit of all 6 seeding tracklets and chi2 calculation
2569 // 13. Hyperplane fit and track quality calculation. See AliTRDtrackerFitter::FitHyperplane() for details.
2570 // 14. Cooking labels for tracklets. Should be done only for MC
2571 // 15. Register seeds.
2574 // Marian Ivanov <M.Ivanov@gsi.de>
2575 // Alexandru Bercuci <A.Bercuci@gsi.de>
2576 // Markus Fasel <M.Fasel@gsi.de>
2578 AliTRDtrackingChamber *chamber = NULL;
2579 AliTRDcluster *c[kNSeedPlanes] = {NULL, NULL, NULL, NULL}; // initilize seeding clusters
2580 AliTRDseedV1 *cseed = &sseed[0]; // initialize tracklets for first track
2581 Int_t ncl, mcl; // working variable for looping over clusters
2582 Int_t index[AliTRDchamberTimeBin::kMaxClustersLayer], jndex[AliTRDchamberTimeBin::kMaxClustersLayer];
2584 // chi2[0] = tracklet chi2 on the Z direction
2585 // chi2[1] = tracklet chi2 on the R direction
2588 // this should be data member of AliTRDtrack TODO
2589 Double_t seedQuality[kMaxTracksStack];
2591 // unpack control parameters
2592 Int_t config = ipar[0];
2593 Int_t ntracks = ipar[1];
2594 Int_t istack = ipar[2];
2595 Int_t planes[kNSeedPlanes]; GetSeedingConfig(config, planes);
2596 Int_t planesExt[kNPlanes-kNSeedPlanes]; GetExtrapolationConfig(config, planesExt);
2599 // Init chambers geometry
2600 Double_t hL[kNPlanes]; // Tilting angle
2601 Float_t padlength[kNPlanes]; // pad lenghts
2602 Float_t padwidth[kNPlanes]; // pad widths
2603 AliTRDpadPlane *pp = NULL;
2604 for(int iplane=0; iplane<kNPlanes; iplane++){
2605 pp = fGeom->GetPadPlane(iplane, istack);
2606 hL[iplane] = TMath::Tan(TMath::DegToRad()*pp->GetTiltingAngle());
2607 padlength[iplane] = pp->GetLengthIPad();
2608 padwidth[iplane] = pp->GetWidthIPad();
2611 // Init anode wire position for chambers
2612 Double_t x0[kNPlanes], // anode wire position
2613 driftLength = .5*AliTRDgeometry::AmThick() - AliTRDgeometry::DrThick(); // drift length
2614 TGeoHMatrix *matrix = NULL;
2615 Double_t loc[] = {AliTRDgeometry::AnodePos(), 0., 0.};
2616 Double_t glb[] = {0., 0., 0.};
2617 AliTRDtrackingChamber **cIter = &stack[0];
2618 for(int iLayer=0; iLayer<kNPlanes; iLayer++,cIter++){
2619 if(!(*cIter)) continue;
2620 if(!(matrix = fGeom->GetClusterMatrix((*cIter)->GetDetector()))){
2621 x0[iLayer] = fgkX0[iLayer];
2624 matrix->LocalToMaster(loc, glb);
2625 x0[iLayer] = glb[0];
2628 AliDebug(2, Form("Making seeds Stack[%d] Config[%d] Tracks[%d]...", istack, config, ntracks));
2630 // Build seeding layers
2633 for(int isl=0; isl<kNSeedPlanes; isl++){
2634 if(!(chamber = stack[planes[isl]])) continue;
2635 if(!chamber->GetSeedingLayer(fSeedTB[isl], fGeom, fkReconstructor)) continue;
2638 if(nlayers < kNSeedPlanes) return ntracks;
2641 // Start finding seeds
2642 Double_t cond0[4], cond1[4], cond2[4];
2644 while((c[3] = (*fSeedTB[3])[icl++])){
2646 fSeedTB[0]->BuildCond(c[3], cond0, 0);
2647 fSeedTB[0]->GetClusters(cond0, index, ncl);
2648 //printf("Found c[3] candidates 0 %d\n", ncl);
2651 c[0] = (*fSeedTB[0])[index[jcl++]];
2653 Double_t dx = c[3]->GetX() - c[0]->GetX();
2654 Double_t dzdx = (c[3]->GetZ() - c[0]->GetZ())/dx;
2655 Double_t dydx = (c[3]->GetY() - c[0]->GetY())/dx;
2656 fSeedTB[1]->BuildCond(c[0], cond1, 1, dzdx, dydx);
2657 fSeedTB[1]->GetClusters(cond1, jndex, mcl);
2658 //printf("Found c[0] candidates 1 %d\n", mcl);
2662 c[1] = (*fSeedTB[1])[jndex[kcl++]];
2664 fSeedTB[2]->BuildCond(c[1], cond2, 2, dzdx, dydx);
2665 c[2] = fSeedTB[2]->GetNearestCluster(cond2);
2666 //printf("Found c[1] candidate 2 %p\n", c[2]);
2669 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].",
2670 c[0]->GetX(), c[0]->GetY(), c[0]->GetZ(),
2671 c[1]->GetX(), c[1]->GetY(), c[1]->GetZ(),
2672 c[2]->GetX(), c[2]->GetY(), c[2]->GetZ(),
2673 c[3]->GetX(), c[3]->GetY(), c[3]->GetZ()));
2675 for (Int_t il = 0; il < kNPlanes; il++) cseed[il].Reset();
2679 AliTRDseedV1 *tseed = &cseed[0];
2681 for(int iLayer=0; iLayer<kNPlanes; iLayer++, tseed++, cIter++){
2682 Int_t det = (*cIter) ? (*cIter)->GetDetector() : -1;
2683 tseed->SetDetector(det);
2684 tseed->SetTilt(hL[iLayer]);
2685 tseed->SetPadLength(padlength[iLayer]);
2686 tseed->SetPadWidth(padwidth[iLayer]);
2687 tseed->SetReconstructor(fkReconstructor);
2688 tseed->SetX0(det<0 ? fR[iLayer]+driftLength : x0[iLayer]);
2689 tseed->Init(GetRiemanFitter());
2690 tseed->SetStandAlone(kTRUE);
2693 Bool_t isFake = kFALSE;
2694 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) >= 2 && fkReconstructor->IsDebugStreaming()){
2695 if (c[0]->GetLabel(0) != c[3]->GetLabel(0)) isFake = kTRUE;
2696 if (c[1]->GetLabel(0) != c[3]->GetLabel(0)) isFake = kTRUE;
2697 if (c[2]->GetLabel(0) != c[3]->GetLabel(0)) isFake = kTRUE;
2700 for(Int_t l = 0; l < kNSeedPlanes; l++) xpos[l] = fSeedTB[l]->GetX();
2702 for(int il=0; il<4; il++) yref[il] = cseed[planes[il]].GetYref(0);
2703 Int_t ll = c[3]->GetLabel(0);
2704 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
2705 Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
2706 AliRieman *rim = GetRiemanFitter();
2707 TTreeSRedirector &cs0 = *fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker);
2709 <<"EventNumber=" << eventNumber
2710 <<"CandidateNumber=" << candidateNumber
2711 <<"isFake=" << isFake
2712 <<"config=" << config
2714 <<"chi2z=" << chi2[0]
2715 <<"chi2y=" << chi2[1]
2716 <<"Y2exp=" << cond2[0]
2717 <<"Z2exp=" << cond2[1]
2718 <<"X0=" << xpos[0] //layer[sLayer]->GetX()
2719 <<"X1=" << xpos[1] //layer[sLayer + 1]->GetX()
2720 <<"X2=" << xpos[2] //layer[sLayer + 2]->GetX()
2721 <<"X3=" << xpos[3] //layer[sLayer + 3]->GetX()
2722 <<"yref0=" << yref[0]
2723 <<"yref1=" << yref[1]
2724 <<"yref2=" << yref[2]
2725 <<"yref3=" << yref[3]
2730 <<"Seed0.=" << &cseed[planes[0]]
2731 <<"Seed1.=" << &cseed[planes[1]]
2732 <<"Seed2.=" << &cseed[planes[2]]
2733 <<"Seed3.=" << &cseed[planes[3]]
2734 <<"RiemanFitter.=" << rim
2737 if(chi2[0] > fkRecoParam->GetChi2Z()/*7./(3. - sLayer)*//*iter*/){
2738 AliDebug(3, Form("Filter on chi2Z [%f].", chi2[0]));
2739 AliTRDtrackerDebug::SetCandidateNumber(AliTRDtrackerDebug::GetCandidateNumber() + 1);
2742 if(chi2[1] > fkRecoParam->GetChi2Y()/*1./(3. - sLayer)*//*iter*/){
2743 AliDebug(3, Form("Filter on chi2Y [%f].", chi2[1]));
2744 AliTRDtrackerDebug::SetCandidateNumber(AliTRDtrackerDebug::GetCandidateNumber() + 1);
2747 //AliInfo("Passed chi2 filter.");
2749 // try attaching clusters to tracklets
2751 AliTRDcluster *cl = NULL;
2752 for(int iLayer=0; iLayer<kNSeedPlanes; iLayer++){
2753 Int_t jLayer = planes[iLayer];
2754 Int_t nNotInChamber = 0;
2755 if(!cseed[jLayer].AttachClusters(stack[jLayer], kTRUE)) continue;
2756 if(/*fkReconstructor->IsHLT()*/kFALSE){
2757 cseed[jLayer].UpdateUsed();
2758 if(!cseed[jLayer].IsOK()) continue;
2760 cseed[jLayer].Fit();
2761 cseed[jLayer].UpdateUsed();
2762 cseed[jLayer].ResetClusterIter();
2763 while((cl = cseed[jLayer].NextCluster())){
2764 if(!cl->IsInChamber()) nNotInChamber++;
2766 //printf("clusters[%d], used[%d], not in chamber[%d]\n", cseed[jLayer].GetN(), cseed[jLayer].GetNUsed(), nNotInChamber);
2767 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
2772 if(mlayers < kNSeedPlanes){
2773 AliDebug(2, Form("Found only %d tracklets out of %d. Skip.", mlayers, kNSeedPlanes));
2774 AliTRDtrackerDebug::SetCandidateNumber(AliTRDtrackerDebug::GetCandidateNumber() + 1);
2778 // temporary exit door for the HLT
2779 if(fkReconstructor->IsHLT()){
2780 // attach clusters to extrapolation chambers
2781 for(int iLayer=0; iLayer<kNPlanes-kNSeedPlanes; iLayer++){
2782 Int_t jLayer = planesExt[iLayer];
2783 if(!(chamber = stack[jLayer])) continue;
2784 if(!cseed[jLayer].AttachClusters(chamber, kTRUE)) continue;
2785 cseed[jLayer].Fit();
2787 //FitTiltedRiemanConstraint(&cseed[0], GetZ());
2788 fTrackQuality[ntracks] = 1.; // dummy value
2790 if(ntracks == kMaxTracksStack) return ntracks;
2796 // Update Seeds and calculate Likelihood
2797 // fit tracklets and cook likelihood
2798 Double_t chi2Vals[4];
2799 chi2Vals[0] = FitTiltedRieman(&cseed[0], kTRUE);
2800 for(int iLayer=0; iLayer<kNSeedPlanes; iLayer++){
2801 Int_t jLayer = planes[iLayer];
2802 cseed[jLayer].Fit(1);
2804 Double_t like = CookLikelihood(&cseed[0], planes); // to be checked
2806 if (TMath::Log(1.E-9 + like) < fkRecoParam->GetTrackLikelihood()){
2807 AliDebug(3, Form("Filter on likelihood %f[%e].", TMath::Log(1.E-9 + like), like));
2808 AliTRDtrackerDebug::SetCandidateNumber(AliTRDtrackerDebug::GetCandidateNumber() + 1);
2811 //AliInfo(Form("Passed likelihood %f[%e].", TMath::Log(1.E-9 + like), like));
2813 // book preliminary results
2814 seedQuality[ntracks] = like;
2815 fSeedLayer[ntracks] = config;/*sLayer;*/
2817 // attach clusters to the extrapolation seeds
2819 for(int iLayer=0; iLayer<kNPlanes-kNSeedPlanes; iLayer++){
2820 Int_t jLayer = planesExt[iLayer];
2821 if(!(chamber = stack[jLayer])) continue;
2823 // fit extrapolated seed
2824 if ((jLayer == 0) && !(cseed[1].IsOK())) continue;
2825 if ((jLayer == 5) && !(cseed[4].IsOK())) continue;
2826 AliTRDseedV1 pseed = cseed[jLayer];
2827 if(!pseed.AttachClusters(chamber, kTRUE)) continue;
2829 cseed[jLayer] = pseed;
2830 chi2Vals[0] = FitTiltedRieman(cseed, kTRUE);
2831 cseed[jLayer].Fit(1);
2835 // AliInfo("Extrapolation done.");
2836 // Debug Stream containing all the 6 tracklets
2837 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) >= 2 && fkReconstructor->IsDebugStreaming()){
2838 TTreeSRedirector &cstreamer = *fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker);
2839 TLinearFitter *tiltedRieman = GetTiltedRiemanFitter();
2840 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
2841 Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
2842 cstreamer << "MakeSeeds1"
2843 << "EventNumber=" << eventNumber
2844 << "CandidateNumber=" << candidateNumber
2845 << "S0.=" << &cseed[0]
2846 << "S1.=" << &cseed[1]
2847 << "S2.=" << &cseed[2]
2848 << "S3.=" << &cseed[3]
2849 << "S4.=" << &cseed[4]
2850 << "S5.=" << &cseed[5]
2851 << "FitterT.=" << tiltedRieman
2855 if(fkRecoParam->HasImproveTracklets()){
2856 if(!ImproveSeedQuality(stack, cseed, chi2Vals[0])){
2857 AliTRDtrackerDebug::SetCandidateNumber(AliTRDtrackerDebug::GetCandidateNumber() + 1);
2858 AliDebug(3, "ImproveSeedQuality() failed.");
2862 // do track fitting with vertex constraint
2863 if(fkRecoParam->IsVertexConstrained()) chi2Vals[1] = FitTiltedRiemanConstraint(&cseed[0], GetZ());
2864 else chi2Vals[1] = -1.;
2865 chi2Vals[2] = GetChi2Z(&cseed[0]);
2866 chi2Vals[3] = GetChi2Phi(&cseed[0]);
2868 // calculate track quality
2869 fTrackQuality[ntracks] = CalculateTrackLikelihood(&chi2Vals[0]);
2871 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) >= 2 && fkReconstructor->IsDebugStreaming()){
2872 TTreeSRedirector &cstreamer = *fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker);
2873 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
2874 Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
2875 TLinearFitter *fitterTC = GetTiltedRiemanFitterConstraint();
2876 TLinearFitter *fitterT = GetTiltedRiemanFitter();
2878 for(Int_t iseed = 0; iseed < kNPlanes; iseed++){
2879 ncls += cseed[iseed].IsOK() ? cseed[iseed].GetN2() : 0;
2881 cstreamer << "MakeSeeds2"
2882 << "EventNumber=" << eventNumber
2883 << "CandidateNumber=" << candidateNumber
2884 << "Chi2TR=" << chi2Vals[0]
2885 << "Chi2TC=" << chi2Vals[1]
2886 << "Nlayers=" << mlayers
2887 << "NClusters=" << ncls
2889 << "S0.=" << &cseed[0]
2890 << "S1.=" << &cseed[1]
2891 << "S2.=" << &cseed[2]
2892 << "S3.=" << &cseed[3]
2893 << "S4.=" << &cseed[4]
2894 << "S5.=" << &cseed[5]
2895 << "FitterT.=" << fitterT
2896 << "FitterTC.=" << fitterTC
2899 if(AliLog::GetDebugLevel("TRD", "AliTRDtrackerV1")){
2900 Double_t pt[]={0., 0.};
2901 for(Int_t il(0); il<kNPlanes; il++){
2902 if(!cseed[il].IsOK()) continue;
2903 pt[0] = GetBz()*kB2C/cseed[il].GetC();
2904 pt[1] = GetBz()*kB2C/cseed[il].GetC(1);
2907 AliDebug(2, Form("Candidate[%2d] pt[%7.3f %7.3f] Q[%e]\n"
2908 " [0] x[%6.2f] n[%2d] nu[%d] OK[%c]\n"
2909 " [1] x[%6.2f] n[%2d] nu[%d] OK[%c]\n"
2910 " [2] x[%6.2f] n[%2d] nu[%d] OK[%c]\n"
2911 " [3] x[%6.2f] n[%2d] nu[%d] OK[%c]\n"
2912 " [4] x[%6.2f] n[%2d] nu[%d] OK[%c]\n"
2913 " [5] x[%6.2f] n[%2d] nu[%d] OK[%c]"
2914 , ntracks, pt[0], pt[1], fTrackQuality[ntracks]
2915 ,cseed[0].GetX(), cseed[0].GetN(), cseed[0].GetNUsed(), cseed[0].IsOK()?'y':'n'
2916 ,cseed[1].GetX(), cseed[1].GetN(), cseed[1].GetNUsed(), cseed[1].IsOK()?'y':'n'
2917 ,cseed[2].GetX(), cseed[2].GetN(), cseed[2].GetNUsed(), cseed[2].IsOK()?'y':'n'
2918 ,cseed[3].GetX(), cseed[3].GetN(), cseed[3].GetNUsed(), cseed[3].IsOK()?'y':'n'
2919 ,cseed[4].GetX(), cseed[4].GetN(), cseed[4].GetNUsed(), cseed[4].IsOK()?'y':'n'
2920 ,cseed[5].GetX(), cseed[5].GetN(), cseed[5].GetNUsed(), cseed[5].IsOK()?'y':'n'));
2923 AliTRDtrackerDebug::SetCandidateNumber(AliTRDtrackerDebug::GetCandidateNumber() + 1);
2924 if(ntracks == kMaxTracksStack){
2925 AliWarning(Form("Number of seeds reached maximum allowed (%d) in stack.", kMaxTracksStack));
2936 //_____________________________________________________________________________
2937 AliTRDtrackV1* AliTRDtrackerV1::MakeTrack(AliTRDseedV1 * const tracklet)
2940 // Build a TRD track out of tracklet candidates
2943 // seeds : array of tracklets
2944 // params : array of track parameters as they are estimated by stand alone tracker. 7 elements.
2945 // [0] - radial position of the track at reference point
2946 // [1] - y position of the fit at [0]
2947 // [2] - z position of the fit at [0]
2948 // [3] - snp of the first tracklet
2949 // [4] - tgl of the first tracklet
2950 // [5] - curvature of the Riemann fit - 1/pt
2951 // [6] - sector rotation angle
2956 // Initialize the TRD track based on the parameters of the fit and a parametric covariance matrix
2957 // (diagonal with constant variance terms TODO - correct parameterization)
2959 // In case of HLT just register the tracklets in the tracker and return values of the Riemann fit. For the
2960 // offline case perform a full Kalman filter on the already found tracklets (see AliTRDtrackerV1::FollowBackProlongation()
2961 // for details). Do also MC label calculation and PID if propagation successfully.
2963 if(fkReconstructor->IsHLT()) FitTiltedRiemanConstraint(tracklet, 0);
2964 Double_t alpha = AliTRDgeometry::GetAlpha();
2965 Double_t shift = AliTRDgeometry::GetAlpha()/2.0;
2967 // find first good tracklet
2968 Int_t idx(0); while(idx<kNPlanes && !tracklet[idx].IsOK()) idx++;
2969 if(idx>2){ AliDebug(1, Form("Found suspect track start @ layer idx[%d]\n"
2970 " %c[0] x0[%f] n[%d] nu[%d] OK[%c]\n"
2971 " %c[1] x0[%f] n[%d] nu[%d] OK[%c]\n"
2972 " %c[2] x0[%f] n[%d] nu[%d] OK[%c]\n"
2973 " %c[3] x0[%f] n[%d] nu[%d] OK[%c]\n"
2974 " %c[4] x0[%f] n[%d] nu[%d] OK[%c]\n"
2975 " %c[5] x0[%f] n[%d] nu[%d] OK[%c]"
2977 ,idx==0?'*':' ', tracklet[0].GetX0(), tracklet[0].GetN(), tracklet[0].GetNUsed(), tracklet[0].IsOK()?'y':'n'
2978 ,idx==1?'*':' ', tracklet[1].GetX0(), tracklet[1].GetN(), tracklet[1].GetNUsed(), tracklet[1].IsOK()?'y':'n'
2979 ,idx==2?'*':' ', tracklet[2].GetX0(), tracklet[2].GetN(), tracklet[2].GetNUsed(), tracklet[2].IsOK()?'y':'n'
2980 ,idx==3?'*':' ', tracklet[3].GetX0(), tracklet[3].GetN(), tracklet[3].GetNUsed(), tracklet[3].IsOK()?'y':'n'
2981 ,idx==4?'*':' ', tracklet[4].GetX0(), tracklet[4].GetN(), tracklet[4].GetNUsed(), tracklet[4].IsOK()?'y':'n'
2982 ,idx==5?'*':' ', tracklet[5].GetX0(), tracklet[5].GetN(), tracklet[5].GetNUsed(), tracklet[5].IsOK()?'y':'n'));
2987 Double_t x(tracklet[idx].GetX0() - dx);
2988 // Build track parameters
2989 Double_t params[] = {
2990 tracklet[idx].GetYref(0) - dx*tracklet[idx].GetYref(1) // y
2991 ,tracklet[idx].GetZref(0) - dx*tracklet[idx].GetZref(1) // z
2992 ,TMath::Sin(TMath::ATan(tracklet[idx].GetYref(1))) // snp
2993 ,tracklet[idx].GetZref(1) / TMath::Sqrt(1. + tracklet[idx].GetYref(1) * tracklet[idx].GetYref(1)) // tgl
2994 ,tracklet[idx].GetC(fkReconstructor->IsHLT()?1:0) // curvature -> 1/pt
2996 Int_t sector(fGeom->GetSector(tracklet[idx].GetDetector()));
2999 c[ 0] = 0.2; // s^2_y
3000 c[ 1] = 0.0; c[ 2] = 2.0; // s^2_z
3001 c[ 3] = 0.0; c[ 4] = 0.0; c[ 5] = 0.02; // s^2_snp
3002 c[ 6] = 0.0; c[ 7] = 0.0; c[ 8] = 0.0; c[ 9] = 0.1; // s^2_tgl
3003 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
3005 AliTRDtrackV1 track(tracklet, params, c, x, sector*alpha+shift);
3007 AliTRDseedV1 *ptrTracklet = NULL;
3009 // skip Kalman filter for HLT
3010 if(/*fkReconstructor->IsHLT()*/kFALSE){
3011 for (Int_t jLayer = 0; jLayer < AliTRDgeometry::kNlayer; jLayer++) {
3012 track.UnsetTracklet(jLayer);
3013 ptrTracklet = &tracklet[jLayer];
3014 if(!ptrTracklet->IsOK()) continue;
3015 if(TMath::Abs(ptrTracklet->GetYref(1) - ptrTracklet->GetYfit(1)) >= .2) continue; // check this condition with Marian
3016 ptrTracklet = SetTracklet(ptrTracklet);
3017 ptrTracklet->UseClusters();
3018 track.SetTracklet(ptrTracklet, fTracklets->GetEntriesFast()-1);
3020 AliTRDtrackV1 *ptrTrack = SetTrack(&track);
3021 ptrTrack->CookPID();
3022 ptrTrack->CookLabel(.9);
3023 ptrTrack->SetReconstructor(fkReconstructor);
3027 // prevent the error message in AliTracker::MeanMaterialBudget: "start point out of geometry"
3028 if(TMath::Abs(track.GetX()) + TMath::Abs(track.GetY()) + TMath::Abs(track.GetZ()) > 10000) return NULL;
3030 track.ResetCovariance(1);
3031 Int_t nc = TMath::Abs(FollowBackProlongation(track));
3032 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) > 5 && fkReconstructor->IsDebugStreaming()){
3033 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
3034 Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
3035 Double_t p[5]; // Track Params for the Debug Stream
3036 track.GetExternalParameters(x, p);
3037 TTreeSRedirector &cs = *fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker);
3039 << "EventNumber=" << eventNumber
3040 << "CandidateNumber=" << candidateNumber
3048 << "Yin=" << params[0]
3049 << "Zin=" << params[1]
3050 << "snpin=" << params[2]
3051 << "tndin=" << params[3]
3052 << "crvin=" << params[4]
3053 << "track.=" << &track
3057 UnsetTrackletsTrack(&track);
3060 AliTRDtrackV1 *ptrTrack = SetTrack(&track);
3061 ptrTrack->SetReconstructor(fkReconstructor);
3062 ptrTrack->CookLabel(.9);
3063 for(Int_t il(kNPlanes); il--;){
3064 if(!(ptrTracklet = ptrTrack->GetTracklet(il))) continue;
3065 ptrTracklet->UseClusters();
3068 // computes PID for track
3069 ptrTrack->CookPID();
3070 // update calibration references using this track
3071 AliTRDCalibraFillHisto *calibra = AliTRDCalibraFillHisto::Instance();
3073 AliInfo("Could not get Calibra instance.");
3074 } else if(calibra->GetHisto2d()){
3075 calibra->UpdateHistogramsV1(ptrTrack);
3081 //____________________________________________________________________
3082 Bool_t AliTRDtrackerV1::ImproveSeedQuality(AliTRDtrackingChamber **stack, AliTRDseedV1 *cseed, Double_t &chi2)
3085 // Sort tracklets according to "quality" and try to "improve" the first 4 worst
3088 // layers : Array of propagation layers for a stack/supermodule
3089 // cseed : Array of 6 seeding tracklets which has to be improved
3092 // cssed : Improved seeds
3094 // Detailed description
3096 // Iterative procedure in which new clusters are searched for each
3097 // tracklet seed such that the seed quality (see AliTRDseed::GetQuality())
3098 // can be maximized. If some optimization is found the old seeds are replaced.
3103 // make a local working copy
3104 AliTRDtrackingChamber *chamber = NULL;
3105 AliTRDseedV1 bseed[AliTRDgeometry::kNlayer];
3107 Float_t quality(1.e3),
3108 lQuality[AliTRDgeometry::kNlayer] = {1.e3, 1.e3, 1.e3, 1.e3, 1.e3, 1.e3};
3110 for(Int_t jLayer=AliTRDgeometry::kNlayer; jLayer--;){
3111 bseed[jLayer] = cseed[jLayer];
3112 if(!bseed[jLayer].IsOK()) continue;
3114 lQuality[jLayer] = bseed[jLayer].GetQuality(kTRUE);
3115 quality += lQuality[jLayer];
3118 AliDebug(2, Form("Start N[%d] Q[%f] chi2[%f]", rLayers, quality, chi2));
3120 for (Int_t iter = 0; iter < 4; iter++) {
3121 // Try better cluster set
3122 Int_t nLayers(0); Float_t qualitynew(0.);
3123 Int_t indexes[4*AliTRDgeometry::kNlayer];
3124 TMath::Sort(Int_t(AliTRDgeometry::kNlayer), lQuality, indexes, kFALSE);
3125 for(Int_t jLayer=AliTRDgeometry::kNlayer; jLayer--;) {
3126 Int_t bLayer = indexes[jLayer];
3127 bseed[bLayer].Reset("c");
3128 if(!(chamber = stack[bLayer])) continue;
3129 if(!bseed[bLayer].AttachClusters(chamber, kTRUE)) continue;
3130 bseed[bLayer].Fit(1);
3131 if(!bseed[bLayer].IsOK()) continue;
3133 lQuality[jLayer] = bseed[jLayer].GetQuality(kTRUE);
3134 qualitynew += lQuality[jLayer];
3136 if(rLayers > nLayers){
3137 AliDebug(1, Form("Lost %d tracklets while improving.", rLayers-nLayers));
3138 return iter>0?kTRUE:kFALSE;
3139 } else rLayers=nLayers;
3140 qualitynew /= rLayers;
3142 if(qualitynew > quality){
3143 AliDebug(4, Form("Quality[%f] worsen in iter[%d] to ref[%f].", qualitynew, iter, quality));
3144 return iter>0?kTRUE:kFALSE;
3145 } else quality = qualitynew;
3147 // try improve track parameters
3148 Float_t chi2new = FitTiltedRieman(bseed, kTRUE);
3150 AliDebug(4, Form("Chi2[%f] worsen in iter[%d] to ref[%f].", chi2new, iter, chi2));
3151 return iter>0?kTRUE:kFALSE;
3152 } else chi2 = chi2new;
3154 // store better tracklets
3155 for(Int_t jLayer=AliTRDgeometry::kNlayer; jLayer--;) cseed[jLayer]=bseed[jLayer];
3156 AliDebug(2, Form("Iter[%d] Q[%f] chi2[%f]", iter, quality, chi2));
3159 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) >= 7 && fkReconstructor->IsDebugStreaming()){
3160 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
3161 Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
3162 TLinearFitter *tiltedRieman = GetTiltedRiemanFitter();
3163 TTreeSRedirector &cstreamer = *fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker);
3164 cstreamer << "ImproveSeedQuality"
3165 << "EventNumber=" << eventNumber
3166 << "CandidateNumber=" << candidateNumber
3167 << "Iteration=" << iter
3168 << "S0.=" << &cseed[0]
3169 << "S1.=" << &cseed[1]
3170 << "S2.=" << &cseed[2]
3171 << "S3.=" << &cseed[3]
3172 << "S4.=" << &cseed[4]
3173 << "S5.=" << &cseed[5]
3174 << "FitterT.=" << tiltedRieman
3179 // we are sure that at least 4 tracklets are OK !
3183 //_________________________________________________________________________
3184 Double_t AliTRDtrackerV1::CalculateTrackLikelihood(Double_t *chi2){
3186 // Calculates the Track Likelihood value. This parameter serves as main quality criterion for
3187 // the track selection
3188 // The likelihood value containes:
3189 // - The chi2 values from the both fitters and the chi2 values in z-direction from a linear fit
3190 // - The Sum of the Parameter |slope_ref - slope_fit|/Sigma of the tracklets
3191 // For all Parameters an exponential dependency is used
3193 // Parameters: - Array of tracklets (AliTRDseedV1) related to the track candidate
3194 // - Array of chi2 values:
3195 // * Non-Constrained Tilted Riemann fit
3196 // * Vertex-Constrained Tilted Riemann fit
3197 // * z-Direction from Linear fit
3198 // Output: - The calculated track likelihood
3203 // Non-constrained Tilted Riemann
3204 Double_t likeChi2TR = TMath::Exp(-chi2[0] * 0.0078);
3205 // Constrained Tilted Riemann
3206 Double_t likeChi2TC(1.);
3208 likeChi2TC = TMath::Exp(-chi2[1] * 0.677);
3209 Double_t r = likeChi2TC/likeChi2TR;
3210 if(r>1.e2){;} // -> a primary track use TC
3211 else if(r<1.e2) // -> a secondary track use TR
3213 else{;} // -> test not conclusive
3215 // Chi2 only on Z direction
3216 Double_t likeChi2Z = TMath::Exp(-chi2[2] * 0.14);
3217 // Chi2 angular resolution
3218 Double_t likeChi2Phi= TMath::Exp(-chi2[3] * 3.23);
3220 Double_t trackLikelihood = likeChi2Z * likeChi2TR * likeChi2TC * likeChi2Phi;
3222 AliDebug(2, Form("Likelihood [%e]\n"
3223 " Rieman : chi2[%f] likelihood[%6.2e]\n"
3224 " Vertex : chi2[%f] likelihood[%6.2e]\n"
3225 " Z : chi2[%f] likelihood[%6.2e]\n"
3226 " Phi : chi2[%f] likelihood[%6.2e]"
3228 , chi2[0], likeChi2TR
3229 , chi2[1], likeChi2TC
3230 , chi2[2], likeChi2Z
3231 , chi2[3], likeChi2Phi
3234 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) >= 2 && fkReconstructor->IsDebugStreaming()){
3235 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
3236 Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
3237 TTreeSRedirector &cstreamer = *fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker);
3238 cstreamer << "CalculateTrackLikelihood0"
3239 << "EventNumber=" << eventNumber
3240 << "CandidateNumber=" << candidateNumber
3241 << "LikeChi2Z=" << likeChi2Z
3242 << "LikeChi2TR=" << likeChi2TR
3243 << "LikeChi2TC=" << likeChi2TC
3244 << "LikeChi2Phi=" << likeChi2Phi
3245 << "TrackLikelihood=" << trackLikelihood
3249 return trackLikelihood;
3252 //____________________________________________________________________
3253 Double_t AliTRDtrackerV1::CookLikelihood(AliTRDseedV1 *cseed, Int_t planes[4])
3256 // Calculate the probability of this track candidate.
3259 // cseeds : array of candidate tracklets
3260 // planes : array of seeding planes (see seeding configuration)
3261 // chi2 : chi2 values (on the Z and Y direction) from the rieman fit of the track.
3266 // Detailed description
3268 // The track quality is estimated based on the following 4 criteria:
3269 // 1. precision of the rieman fit on the Y direction (likea)
3270 // 2. chi2 on the Y direction (likechi2y)
3271 // 3. chi2 on the Z direction (likechi2z)
3272 // 4. number of attached clusters compared to a reference value
3273 // (see AliTRDrecoParam::fkFindable) (likeN)
3275 // The distributions for each type of probabilities are given below as of
3276 // (date). They have to be checked to assure consistency of estimation.
3279 // ratio of the total number of clusters/track which are expected to be found by the tracker.
3280 Double_t chi2y = GetChi2Y(&cseed[0]);
3281 Double_t chi2z = GetChi2Z(&cseed[0]);
3283 Float_t nclusters = 0.;
3284 Double_t sumda = 0.;
3285 for(UChar_t ilayer = 0; ilayer < 4; ilayer++){
3286 Int_t jlayer = planes[ilayer];
3287 nclusters += cseed[jlayer].GetN2();
3288 sumda += TMath::Abs(cseed[jlayer].GetYfit(1) - cseed[jlayer].GetYref(1));
3292 Double_t likea = TMath::Exp(-sumda * fkRecoParam->GetPhiSlope());
3293 Double_t likechi2y = 0.0000000001;
3294 if (fkReconstructor->IsCosmic() || chi2y < fkRecoParam->GetChi2YCut()) likechi2y += TMath::Exp(-TMath::Sqrt(chi2y) * fkRecoParam->GetChi2YSlope());
3295 Double_t likechi2z = TMath::Exp(-chi2z * fkRecoParam->GetChi2ZSlope());
3296 Double_t likeN = TMath::Exp(-(fkRecoParam->GetNMeanClusters() - nclusters) / fkRecoParam->GetNSigmaClusters());
3297 Double_t like = likea * likechi2y * likechi2z * likeN;
3299 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) >= 2 && fkReconstructor->IsDebugStreaming()){
3300 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
3301 Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
3302 Int_t nTracklets = 0; Float_t meanNcls = 0;
3303 for(Int_t iseed=0; iseed < kNPlanes; iseed++){
3304 if(!cseed[iseed].IsOK()) continue;
3306 meanNcls += cseed[iseed].GetN2();
3308 if(nTracklets) meanNcls /= nTracklets;
3309 // The Debug Stream contains the seed
3310 TTreeSRedirector &cstreamer = *fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker);
3311 cstreamer << "CookLikelihood"
3312 << "EventNumber=" << eventNumber
3313 << "CandidateNumber=" << candidateNumber
3314 << "tracklet0.=" << &cseed[0]
3315 << "tracklet1.=" << &cseed[1]
3316 << "tracklet2.=" << &cseed[2]
3317 << "tracklet3.=" << &cseed[3]
3318 << "tracklet4.=" << &cseed[4]
3319 << "tracklet5.=" << &cseed[5]
3320 << "sumda=" << sumda
3321 << "chi2y=" << chi2y
3322 << "chi2z=" << chi2z
3323 << "likea=" << likea
3324 << "likechi2y=" << likechi2y
3325 << "likechi2z=" << likechi2z
3326 << "nclusters=" << nclusters
3327 << "likeN=" << likeN
3329 << "meanncls=" << meanNcls
3336 //____________________________________________________________________
3337 void AliTRDtrackerV1::GetSeedingConfig(Int_t iconfig, Int_t planes[4])
3340 // Map seeding configurations to detector planes.
3343 // iconfig : configuration index
3344 // planes : member planes of this configuration. On input empty.
3347 // planes : contains the planes which are defining the configuration
3349 // Detailed description
3351 // Here is the list of seeding planes configurations together with
3352 // their topological classification:
3370 // The topologic quality is modeled as follows:
3371 // 1. The general model is define by the equation:
3372 // p(conf) = exp(-conf/2)
3373 // 2. According to the topologic classification, configurations from the same
3374 // class are assigned the agerage value over the model values.
3375 // 3. Quality values are normalized.
3377 // The topologic quality distribution as function of configuration is given below:
3379 // <img src="gif/topologicQA.gif">
3384 case 0: // 5432 TQ 0
3390 case 1: // 4321 TQ 0
3396 case 2: // 3210 TQ 0
3402 case 3: // 5321 TQ 1
3408 case 4: // 4210 TQ 1
3414 case 5: // 5431 TQ 1
3420 case 6: // 4320 TQ 1
3426 case 7: // 5430 TQ 2
3432 case 8: // 5210 TQ 2
3438 case 9: // 5421 TQ 3
3444 case 10: // 4310 TQ 3
3450 case 11: // 5410 TQ 4
3456 case 12: // 5420 TQ 5
3462 case 13: // 5320 TQ 5
3468 case 14: // 5310 TQ 5
3477 //____________________________________________________________________
3478 void AliTRDtrackerV1::GetExtrapolationConfig(Int_t iconfig, Int_t planes[2])
3481 // Returns the extrapolation planes for a seeding configuration.
3484 // iconfig : configuration index
3485 // planes : planes which are not in this configuration. On input empty.
3488 // planes : contains the planes which are not in the configuration
3490 // Detailed description
3494 case 0: // 5432 TQ 0
3498 case 1: // 4321 TQ 0
3502 case 2: // 3210 TQ 0
3506 case 3: // 5321 TQ 1
3510 case 4: // 4210 TQ 1
3514 case 5: // 5431 TQ 1
3518 case 6: // 4320 TQ 1
3522 case 7: // 5430 TQ 2
3526 case 8: // 5210 TQ 2
3530 case 9: // 5421 TQ 3
3534 case 10: // 4310 TQ 3
3538 case 11: // 5410 TQ 4
3542 case 12: // 5420 TQ 5
3546 case 13: // 5320 TQ 5
3550 case 14: // 5310 TQ 5
3557 //____________________________________________________________________
3558 AliCluster* AliTRDtrackerV1::GetCluster(Int_t idx) const
3560 if(!fClusters) return NULL;
3561 Int_t ncls = fClusters->GetEntriesFast();
3562 return idx >= 0 && idx < ncls ? (AliCluster*)fClusters->UncheckedAt(idx) : NULL;
3565 //____________________________________________________________________
3566 AliTRDseedV1* AliTRDtrackerV1::GetTracklet(Int_t idx) const
3568 if(!fTracklets) return NULL;
3569 Int_t ntrklt = fTracklets->GetEntriesFast();
3570 return idx >= 0 && idx < ntrklt ? (AliTRDseedV1*)fTracklets->UncheckedAt(idx) : NULL;
3573 //____________________________________________________________________
3574 AliKalmanTrack* AliTRDtrackerV1::GetTrack(Int_t idx) const
3576 if(!fTracks) return NULL;
3577 Int_t ntrk = fTracks->GetEntriesFast();
3578 return idx >= 0 && idx < ntrk ? (AliKalmanTrack*)fTracks->UncheckedAt(idx) : NULL;
3583 // //_____________________________________________________________________________
3584 // Int_t AliTRDtrackerV1::Freq(Int_t n, const Int_t *inlist
3585 // , Int_t *outlist, Bool_t down)
3588 // // Sort eleements according occurancy
3589 // // The size of output array has is 2*n
3596 // Int_t *sindexS = new Int_t[n]; // Temporary array for sorting
3597 // Int_t *sindexF = new Int_t[2*n];
3598 // for (Int_t i = 0; i < n; i++) {
3602 // TMath::Sort(n,inlist,sindexS,down);
3604 // Int_t last = inlist[sindexS[0]];
3605 // Int_t val = last;
3607 // sindexF[0+n] = last;
3608 // Int_t countPos = 0;
3610 // // Find frequency
3611 // for (Int_t i = 1; i < n; i++) {
3612 // val = inlist[sindexS[i]];
3613 // if (last == val) {
3614 // sindexF[countPos]++;
3618 // sindexF[countPos+n] = val;
3619 // sindexF[countPos]++;
3623 // if (last == val) {
3627 // // Sort according frequency
3628 // TMath::Sort(countPos,sindexF,sindexS,kTRUE);
3630 // for (Int_t i = 0; i < countPos; i++) {
3631 // outlist[2*i ] = sindexF[sindexS[i]+n];
3632 // outlist[2*i+1] = sindexF[sindexS[i]];
3635 // delete [] sindexS;
3636 // delete [] sindexF;
3643 //____________________________________________________________________
3644 void AliTRDtrackerV1::ResetSeedTB()
3646 // reset buffer for seeding time bin layers. If the time bin
3647 // layers are not allocated this function allocates them
3649 for(Int_t isl=0; isl<kNSeedPlanes; isl++){
3650 if(!fSeedTB[isl]) fSeedTB[isl] = new AliTRDchamberTimeBin();
3651 else fSeedTB[isl]->Clear();
3656 //_____________________________________________________________________________
3657 Float_t AliTRDtrackerV1::GetChi2Y(const AliTRDseedV1 * const tracklets) const
3659 // Calculates normalized chi2 in y-direction
3660 // chi2 = Sum chi2 / n_tracklets
3662 Double_t chi2 = 0.; Int_t n = 0;
3663 for(Int_t ipl = kNPlanes; ipl--;){
3664 if(!tracklets[ipl].IsOK()) continue;
3665 chi2 += tracklets[ipl].GetChi2Y();
3668 return n ? chi2/n : 0.;
3671 //_____________________________________________________________________________
3672 Float_t AliTRDtrackerV1::GetChi2Z(const AliTRDseedV1 *const tracklets) const
3674 // Calculates normalized chi2 in z-direction
3675 // chi2 = Sum chi2 / n_tracklets
3677 Double_t chi2 = 0; Int_t n = 0;
3678 for(Int_t ipl = kNPlanes; ipl--;){
3679 if(!tracklets[ipl].IsOK()) continue;
3680 chi2 += tracklets[ipl].GetChi2Z();
3683 return n ? chi2/n : 0.;
3686 //_____________________________________________________________________________
3687 Float_t AliTRDtrackerV1::GetChi2Phi(const AliTRDseedV1 *const tracklets) const
3689 // Calculates normalized chi2 for angular resolution
3690 // chi2 = Sum chi2 / n_tracklets
3692 Double_t chi2 = 0; Int_t n = 0;
3693 for (Int_t iLayer = 0; iLayer < kNPlanes; iLayer++) {
3694 if(!tracklets[iLayer].IsOK()) continue;
3695 chi2 += tracklets[iLayer].GetChi2Phi();
3698 return n ? chi2/n: 0.;
3701 //____________________________________________________________________
3702 Float_t AliTRDtrackerV1::CalculateReferenceX(const AliTRDseedV1 *const tracklets){
3704 // Calculates the reference x-position for the tilted Rieman fit defined as middle
3705 // of the stack (middle between layers 2 and 3). For the calculation all the tracklets
3706 // are taken into account
3708 // Parameters: - Array of tracklets(AliTRDseedV1)
3710 // Output: - The reference x-position(Float_t)
3711 // Only kept for compatibility with the old code
3713 Int_t nDistances = 0;
3714 Float_t meanDistance = 0.;
3715 Int_t startIndex = 5;
3716 for(Int_t il =5; il > 0; il--){
3717 if(tracklets[il].IsOK() && tracklets[il -1].IsOK()){
3718 Float_t xdiff = tracklets[il].GetX0() - tracklets[il -1].GetX0();
3719 meanDistance += xdiff;
3722 if(tracklets[il].IsOK()) startIndex = il;
3724 if(tracklets[0].IsOK()) startIndex = 0;
3726 // We should normally never get here
3727 Float_t xpos[2]; memset(xpos, 0, sizeof(Float_t) * 2);
3728 Int_t iok = 0, idiff = 0;
3729 // This attempt is worse and should be avoided:
3730 // check for two chambers which are OK and repeat this without taking the mean value
3731 // Strategy avoids a division by 0;
3732 for(Int_t il = 5; il >= 0; il--){
3733 if(tracklets[il].IsOK()){
3734 xpos[iok] = tracklets[il].GetX0();
3738 if(iok) idiff++; // to get the right difference;
3742 meanDistance = (xpos[0] - xpos[1])/idiff;
3745 // we have do not even have 2 layers which are OK? The we do not need to fit at all
3750 meanDistance /= nDistances;
3752 return tracklets[startIndex].GetX0() + (2.5 - startIndex) * meanDistance - 0.5 * (AliTRDgeometry::AmThick() + AliTRDgeometry::DrThick());
3755 //_____________________________________________________________________________
3756 Double_t AliTRDtrackerV1::FitTiltedRiemanV1(AliTRDseedV1 *const tracklets){
3758 // Track Fitter Function using the new class implementation of
3761 AliTRDtrackFitterRieman fitter;
3762 fitter.SetRiemanFitter(GetTiltedRiemanFitter());
3764 for(Int_t il = 0; il < AliTRDgeometry::kNlayer; il++) fitter.SetTracklet(il, &tracklets[il]);
3765 Double_t chi2 = fitter.Eval();
3766 // Update the tracklets
3767 Double_t cov[15]; Double_t x0;
3768 memset(cov, 0, sizeof(Double_t) * 15);
3769 for(Int_t il = 0; il < AliTRDgeometry::kNlayer; il++){
3770 x0 = tracklets[il].GetX0();
3771 tracklets[il].SetYref(0, fitter.GetYat(x0));
3772 tracklets[il].SetZref(0, fitter.GetZat(x0));
3773 tracklets[il].SetYref(1, fitter.GetDyDxAt(x0));
3774 tracklets[il].SetZref(1, fitter.GetDzDx());
3775 tracklets[il].SetC(fitter.GetCurvature());
3776 fitter.GetCovAt(x0, cov);
3777 tracklets[il].SetCovRef(cov);
3778 tracklets[il].SetChi2(chi2);
3783 //____________________________________________________________________
3784 void AliTRDtrackerV1::UnsetTrackletsTrack(const AliTRDtrackV1 * const track)
3786 // Remove tracklets from tracker list attached to "track"
3788 for(Int_t il(0); il<kNPlanes; il++){
3789 if((idx = track->GetTrackletIndex(il)) < 0) continue;
3790 delete (fTracklets->RemoveAt(idx));
3795 ///////////////////////////////////////////////////////
3797 // Resources of class AliTRDLeastSquare //
3799 ///////////////////////////////////////////////////////
3801 //_____________________________________________________________________________
3802 AliTRDtrackerV1::AliTRDLeastSquare::AliTRDLeastSquare(){
3804 // Constructor of the nested class AliTRDtrackFitterLeastSquare
3806 // Fast solving linear regresion in 2D
3808 // The data members have the following meaning
3819 // fCovarianceMatrix[0] : s2a
3820 // fCovarianceMatrix[1] : s2b
3821 // fCovarianceMatrix[2] : cov(ab)
3823 memset(fParams, 0, sizeof(Double_t) * 2);
3824 memset(fSums, 0, sizeof(Double_t) * 6);
3825 memset(fCovarianceMatrix, 0, sizeof(Double_t) * 3);
3829 //_____________________________________________________________________________
3830 void AliTRDtrackerV1::AliTRDLeastSquare::AddPoint(const Double_t *const x, Double_t y, Double_t sigmaY){
3832 // Adding Point to the fitter
3835 Double_t weight = 1/(sigmaY > 1e-9 ? sigmaY : 1e-9);
3837 const Double_t &xpt = *x;
3838 // printf("Adding point x = %f, y = %f, sigma = %f\n", xpt, y, sigmaY);
3840 fSums[1] += weight * xpt;
3841 fSums[2] += weight * y;
3842 fSums[3] += weight * xpt * y;
3843 fSums[4] += weight * xpt * xpt;
3844 fSums[5] += weight * y * y;
3847 //_____________________________________________________________________________
3848 void AliTRDtrackerV1::AliTRDLeastSquare::RemovePoint(const Double_t *const x, Double_t y, Double_t sigmaY){
3850 // Remove Point from the sample
3853 Double_t weight = 1/(sigmaY > 1e-9 ? sigmaY : 1e-9);
3855 const Double_t &xpt = *x;
3857 fSums[1] -= weight * xpt;
3858 fSums[2] -= weight * y;
3859 fSums[3] -= weight * xpt * y;
3860 fSums[4] -= weight * xpt * xpt;
3861 fSums[5] -= weight * y * y;
3864 //_____________________________________________________________________________
3865 Bool_t AliTRDtrackerV1::AliTRDLeastSquare::Eval(){
3867 // Evaluation of the fit:
3868 // Calculation of the parameters
3869 // Calculation of the covariance matrix
3872 Double_t det = fSums[0] * fSums[4] - fSums[1] *fSums[1];
3873 if(TMath::Abs(det)<1.e-30) return kFALSE;
3875 // for(Int_t isum = 0; isum < 5; isum++)
3876 // printf("fSums[%d] = %f\n", isum, fSums[isum]);
3877 // printf("denominator = %f\n", denominator);
3878 fParams[0] = (fSums[2] * fSums[4] - fSums[1] * fSums[3])/det;
3879 fParams[1] = (fSums[0] * fSums[3] - fSums[1] * fSums[2])/det;
3880 // printf("fParams[0] = %f, fParams[1] = %f\n", fParams[0], fParams[1]);
3882 // Covariance matrix
3883 Double_t den = fSums[0]*fSums[4] - fSums[1]*fSums[1];
3884 fCovarianceMatrix[0] = fSums[4] / den;
3885 fCovarianceMatrix[1] = fSums[0] / den;
3886 fCovarianceMatrix[2] = -fSums[1] / den;
3887 /* fCovarianceMatrix[0] = fSums[4] / fSums[0] - fSums[1] * fSums[1] / (fSums[0] * fSums[0]);
3888 fCovarianceMatrix[1] = fSums[5] / fSums[0] - fSums[2] * fSums[2] / (fSums[0] * fSums[0]);
3889 fCovarianceMatrix[2] = fSums[3] / fSums[0] - fSums[1] * fSums[2] / (fSums[0] * fSums[0]);*/
3896 //_____________________________________________________________________________
3897 Double_t AliTRDtrackerV1::AliTRDLeastSquare::GetFunctionValue(const Double_t *const xpos) const {
3899 // Returns the Function value of the fitted function at a given x-position
3901 return fParams[0] + fParams[1] * (*xpos);
3904 //_____________________________________________________________________________
3905 void AliTRDtrackerV1::AliTRDLeastSquare::GetCovarianceMatrix(Double_t *storage) const {
3907 // Copies the values of the covariance matrix into the storage
3909 memcpy(storage, fCovarianceMatrix, sizeof(Double_t) * 3);
3912 //_____________________________________________________________________________
3913 void AliTRDtrackerV1::AliTRDLeastSquare::Reset(){
3917 memset(fParams, 0, sizeof(Double_t) * 2);
3918 memset(fCovarianceMatrix, 0, sizeof(Double_t) * 3);
3919 memset(fSums, 0, sizeof(Double_t) * 6);
3922 ///////////////////////////////////////////////////////
3924 // Resources of class AliTRDtrackFitterRieman //
3926 ///////////////////////////////////////////////////////
3928 //_____________________________________________________________________________
3929 AliTRDtrackerV1::AliTRDtrackFitterRieman::AliTRDtrackFitterRieman():
3935 fSysClusterError(0.)
3938 // Default constructor
3940 fZfitter = new AliTRDLeastSquare;
3941 fCovarPolY = new TMatrixD(3,3);
3942 fCovarPolZ = new TMatrixD(2,2);
3943 memset(fTracklets, 0, sizeof(AliTRDseedV1 *) * 6);
3944 memset(fParameters, 0, sizeof(Double_t) * 5);
3945 memset(fSumPolY, 0, sizeof(Double_t) * 5);
3946 memset(fSumPolZ, 0, sizeof(Double_t) * 2);
3949 //_____________________________________________________________________________
3950 AliTRDtrackerV1::AliTRDtrackFitterRieman::~AliTRDtrackFitterRieman(){
3954 if(fZfitter) delete fZfitter;
3955 if(fCovarPolY) delete fCovarPolY;
3956 if(fCovarPolZ) delete fCovarPolZ;
3959 //_____________________________________________________________________________
3960 void AliTRDtrackerV1::AliTRDtrackFitterRieman::Reset(){
3965 fTrackFitter->StoreData(kTRUE);
3966 fTrackFitter->ClearPoints();
3972 memset(fTracklets, 0, sizeof(AliTRDseedV1 *) * AliTRDgeometry::kNlayer);
3973 memset(fParameters, 0, sizeof(Double_t) * 5);
3974 memset(fSumPolY, 0, sizeof(Double_t) * 5);
3975 memset(fSumPolZ, 0, sizeof(Double_t) * 2);
3976 for(Int_t irow = 0; irow < fCovarPolY->GetNrows(); irow++)
3977 for(Int_t icol = 0; icol < fCovarPolY->GetNcols(); icol++){
3978 (*fCovarPolY)(irow, icol) = 0.;
3979 if(irow < 2 && icol < 2)
3980 (*fCovarPolZ)(irow, icol) = 0.;
3984 //_____________________________________________________________________________
3985 void AliTRDtrackerV1::AliTRDtrackFitterRieman::SetTracklet(Int_t itr, AliTRDseedV1 *tracklet){
3987 // Add tracklet into the fitter
3989 if(itr >= AliTRDgeometry::kNlayer) return;
3990 fTracklets[itr] = tracklet;
3993 //_____________________________________________________________________________
3994 Double_t AliTRDtrackerV1::AliTRDtrackFitterRieman::Eval(){
3997 // 1. Apply linear transformation and store points in the fitter
3998 // 2. Evaluate the fit
3999 // 3. Check if the result of the fit in z-direction is reasonable
4001 // 3a. Fix the parameters 3 and 4 with the results of a simple least
4003 // 3b. Redo the fit with the fixed parameters
4004 // 4. Store fit results (parameters and errors)
4009 fXref = CalculateReferenceX();
4010 for(Int_t il = 0; il < AliTRDgeometry::kNlayer; il++) UpdateFitters(fTracklets[il]);
4011 if(!fTrackFitter->GetNpoints()) return 1e10;
4013 fTrackFitter->Eval();
4015 fParameters[3] = fTrackFitter->GetParameter(3);
4016 fParameters[4] = fTrackFitter->GetParameter(4);
4017 if(!CheckAcceptable(fParameters[3], fParameters[4])) {
4018 fTrackFitter->FixParameter(3, fZfitter->GetFunctionValue(&fXref));
4019 fTrackFitter->FixParameter(4, fZfitter->GetFunctionParameter(1));
4020 fTrackFitter->Eval();
4021 fTrackFitter->ReleaseParameter(3);
4022 fTrackFitter->ReleaseParameter(4);
4023 fParameters[3] = fTrackFitter->GetParameter(3);
4024 fParameters[4] = fTrackFitter->GetParameter(4);
4026 // Update the Fit Parameters and the errors
4027 fParameters[0] = fTrackFitter->GetParameter(0);
4028 fParameters[1] = fTrackFitter->GetParameter(1);
4029 fParameters[2] = fTrackFitter->GetParameter(2);
4031 // Prepare Covariance estimation
4032 (*fCovarPolY)(0,0) = fSumPolY[0]; (*fCovarPolY)(1,1) = fSumPolY[2]; (*fCovarPolY)(2,2) = fSumPolY[4];
4033 (*fCovarPolY)(1,0) = (*fCovarPolY)(0,1) = fSumPolY[1];
4034 (*fCovarPolY)(2,0) = (*fCovarPolY)(0,2) = fSumPolY[2];
4035 (*fCovarPolY)(2,1) = (*fCovarPolY)(1,2) = fSumPolY[3];
4036 fCovarPolY->Invert();
4037 (*fCovarPolZ)(0,0) = fSumPolZ[0]; (*fCovarPolZ)(1,1) = fSumPolZ[2];
4038 (*fCovarPolZ)(1,0) = (*fCovarPolZ)(0,1) = fSumPolZ[1];
4039 fCovarPolZ->Invert();
4040 return fTrackFitter->GetChisquare() / fTrackFitter->GetNpoints();
4043 //_____________________________________________________________________________
4044 void AliTRDtrackerV1::AliTRDtrackFitterRieman::UpdateFitters(AliTRDseedV1 * const tracklet){
4046 // Does the transformations and updates the fitters
4047 // The following transformation is applied
4049 AliTRDcluster *cl = NULL;
4050 Double_t x, y, z, dx, t, w, we, yerr, zerr;
4052 if(!tracklet || !tracklet->IsOK()) return;
4053 Double_t tilt = tracklet->GetTilt();
4054 for(Int_t itb = 0; itb < AliTRDseedV1::kNclusters; itb++){
4055 if(!(cl = tracklet->GetClusters(itb))) continue;
4056 if(!cl->IsInChamber()) continue;
4057 if (!tracklet->IsUsable(itb)) continue;
4064 uvt[0] = 2. * x * t;
4066 uvt[2] = 2. * tilt * t;
4067 uvt[3] = 2. * tilt * dx * t;
4068 w = 2. * (y + tilt*z) * t;
4069 // error definition changes for the different calls
4071 we *= TMath::Sqrt(cl->GetSigmaY2()+tilt*tilt*cl->GetSigmaZ2());
4072 // Update sums for error calculation
4073 yerr = 1./(TMath::Sqrt(cl->GetSigmaY2()) + fSysClusterError);
4075 zerr = 1./cl->GetSigmaZ2();
4076 for(Int_t ipol = 0; ipol < 5; ipol++){
4077 fSumPolY[ipol] += yerr;
4080 fSumPolZ[ipol] += zerr;
4084 fTrackFitter->AddPoint(uvt, w, we);
4085 fZfitter->AddPoint(&x, z, static_cast<Double_t>(TMath::Sqrt(cl->GetSigmaZ2())));
4089 //_____________________________________________________________________________
4090 Bool_t AliTRDtrackerV1::AliTRDtrackFitterRieman::CheckAcceptable(Double_t offset, Double_t slope){
4092 // Check whether z-results are acceptable
4093 // Definition: Distance between tracklet fit and track fit has to be
4094 // less then half a padlength
4095 // Point of comparision is at the anode wire
4097 Bool_t acceptablez = kTRUE;
4098 Double_t zref = 0.0;
4099 for (Int_t iLayer = 0; iLayer < kNPlanes; iLayer++) {
4100 if(!fTracklets[iLayer]->IsOK()) continue;
4101 zref = offset + slope * (fTracklets[iLayer]->GetX0() - fXref);
4102 if (TMath::Abs(fTracklets[iLayer]->GetZfit(0) - zref) > fTracklets[iLayer]->GetPadLength() * 0.5 + 1.0)
4103 acceptablez = kFALSE;
4108 //_____________________________________________________________________________
4109 Double_t AliTRDtrackerV1::AliTRDtrackFitterRieman::GetYat(Double_t x) const {
4111 // Calculate y position out of the track parameters
4112 // y: R^2 = (x - x0)^2 + (y - y0)^2
4113 // => y = y0 +/- Sqrt(R^2 - (x - x0)^2)
4114 // R = Sqrt() = 1/Curvature
4115 // => y = y0 +/- Sqrt(1/Curvature^2 - (x - x0)^2)
4118 Double_t disc = (x * fParameters[0] + fParameters[1]);
4119 disc = 1 - fParameters[0]*fParameters[2] + fParameters[1]*fParameters[1] - disc*disc;
4121 disc = TMath::Sqrt(disc);
4122 y = (1.0 - disc) / fParameters[0];
4127 //_____________________________________________________________________________
4128 Double_t AliTRDtrackerV1::AliTRDtrackFitterRieman::GetZat(Double_t x) const {
4130 // Return z position for a given x position
4131 // Simple linear function
4133 return fParameters[3] + fParameters[4] * (x - fXref);
4136 //_____________________________________________________________________________
4137 Double_t AliTRDtrackerV1::AliTRDtrackFitterRieman::GetDyDxAt(Double_t x) const {
4139 // Calculate dydx at a given radial position out of the track parameters
4140 // dy: R^2 = (x - x0)^2 + (y - y0)^2
4141 // => y = +/- Sqrt(R^2 - (x - x0)^2) + y0
4142 // => dy/dx = (x - x0)/Sqrt(R^2 - (x - x0)^2)
4143 // Curvature: cr = 1/R = a/Sqrt(1 + b^2 - c*a)
4144 // => dy/dx = (x - x0)/(1/(cr^2) - (x - x0)^2)
4146 Double_t x0 = -fParameters[1] / fParameters[0];
4147 Double_t curvature = GetCurvature();
4149 if (-fParameters[2] * fParameters[0] + fParameters[1] * fParameters[1] + 1 > 0) {
4150 if (1.0/(curvature * curvature) - (x - x0) * (x - x0) > 0.0) {
4151 Double_t yderiv = (x - x0) / TMath::Sqrt(1.0/(curvature * curvature) - (x - x0) * (x - x0));
4152 if (fParameters[0] < 0) yderiv *= -1.0;
4159 //_____________________________________________________________________________
4160 Double_t AliTRDtrackerV1::AliTRDtrackFitterRieman::GetCurvature() const {
4162 // Calculate track curvature
4165 Double_t curvature = 1.0 + fParameters[1]*fParameters[1] - fParameters[2]*fParameters[0];
4166 if (curvature > 0.0)
4167 curvature = fParameters[0] / TMath::Sqrt(curvature);
4171 //_____________________________________________________________________________
4172 void AliTRDtrackerV1::AliTRDtrackFitterRieman::GetCovAt(Double_t x, Double_t *cov) const {
4174 // Error Definition according to gauss error propagation
4176 TMatrixD transform(3,3);
4177 transform(0,0) = transform(1,1) = transform(2,2) = 1;
4178 transform(0,1) = transform(1,2) = x;
4179 transform(0,2) = x*x;
4180 TMatrixD covariance(transform, TMatrixD::kMult, *fCovarPolY);
4181 covariance *= transform.T();
4182 cov[0] = covariance(0,0);
4183 TMatrixD transformZ(2,2);
4184 transformZ(0,0) = transformZ(1,1) = 1;
4185 transformZ(0,1) = x;
4186 TMatrixD covarZ(transformZ, TMatrixD::kMult, *fCovarPolZ);
4187 covarZ *= transformZ.T();
4188 cov[1] = covarZ(0,0);
4192 //____________________________________________________________________
4193 Double_t AliTRDtrackerV1::AliTRDtrackFitterRieman::CalculateReferenceX(){
4195 // Calculates the reference x-position for the tilted Rieman fit defined as middle
4196 // of the stack (middle between layers 2 and 3). For the calculation all the tracklets
4197 // are taken into account
4199 // Parameters: - Array of tracklets(AliTRDseedV1)
4201 // Output: - The reference x-position(Float_t)
4203 Int_t nDistances = 0;
4204 Float_t meanDistance = 0.;
4205 Int_t startIndex = 5;
4206 for(Int_t il =5; il > 0; il--){
4207 if(fTracklets[il]->IsOK() && fTracklets[il -1]->IsOK()){
4208 Float_t xdiff = fTracklets[il]->GetX0() - fTracklets[il -1]->GetX0();
4209 meanDistance += xdiff;
4212 if(fTracklets[il]->IsOK()) startIndex = il;
4214 if(fTracklets[0]->IsOK()) startIndex = 0;
4216 // We should normally never get here
4217 Float_t xpos[2]; memset(xpos, 0, sizeof(Float_t) * 2);
4218 Int_t iok = 0, idiff = 0;
4219 // This attempt is worse and should be avoided:
4220 // check for two chambers which are OK and repeat this without taking the mean value
4221 // Strategy avoids a division by 0;
4222 for(Int_t il = 5; il >= 0; il--){
4223 if(fTracklets[il]->IsOK()){
4224 xpos[iok] = fTracklets[il]->GetX0();
4228 if(iok) idiff++; // to get the right difference;
4232 meanDistance = (xpos[0] - xpos[1])/idiff;
4235 // we have do not even have 2 layers which are OK? The we do not need to fit at all
4240 meanDistance /= nDistances;
4242 return fTracklets[startIndex]->GetX0() + (2.5 - startIndex) * meanDistance - 0.5 * (AliTRDgeometry::AmThick() + AliTRDgeometry::DrThick());