1 /**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
7 * Permission to use, copy, modify and distribute this software and its *
8 * documentation strictly for non-commercial purposes is hereby granted *
9 * without fee, provided that the above copyright notice appears in all *
10 * copies and that both the copyright notice and this permission notice *
11 * appear in the supporting documentation. The authors make no claims *
12 * about the suitability of this software for any purpose. It is *
13 * provided "as is" without express or implied warranty. *
14 **************************************************************************/
18 ///////////////////////////////////////////////////////////////////////////////
23 // Alex Bercuci <A.Bercuci@gsi.de> //
24 // Markus Fasel <M.Fasel@gsi.de> //
26 ///////////////////////////////////////////////////////////////////////////////
29 #include <TDirectory.h>
30 #include <TLinearFitter.h>
32 #include <TClonesArray.h>
33 #include <TTreeStream.h>
34 #include <TGeoMatrix.h>
35 #include <TGeoManager.h>
38 #include "AliMathBase.h"
39 #include "AliESDEvent.h"
40 #include "AliGeomManager.h"
41 #include "AliRieman.h"
42 #include "AliTrackPointArray.h"
44 #include "AliTRDgeometry.h"
45 #include "AliTRDpadPlane.h"
46 #include "AliTRDcalibDB.h"
47 #include "AliTRDReconstructor.h"
48 #include "AliTRDCalibraFillHisto.h"
49 #include "AliTRDrecoParam.h"
51 #include "AliTRDcluster.h"
52 #include "AliTRDdigitsParam.h"
53 #include "AliTRDseedV1.h"
54 #include "AliTRDtrackV1.h"
55 #include "AliTRDtrackerV1.h"
56 #include "AliTRDtrackerDebug.h"
57 #include "AliTRDtrackingChamber.h"
58 #include "AliTRDchamberTimeBin.h"
60 ClassImp(AliTRDtrackerV1)
61 ClassImp(AliTRDtrackerV1::AliTRDLeastSquare)
62 ClassImp(AliTRDtrackerV1::AliTRDtrackFitterRieman)
64 const Float_t AliTRDtrackerV1::fgkMinClustersInTrack = 0.5; //
65 const Float_t AliTRDtrackerV1::fgkLabelFraction = 0.8; //
66 const Double_t AliTRDtrackerV1::fgkMaxChi2 = 12.0; //
67 const Double_t AliTRDtrackerV1::fgkMaxSnp = 0.95; // Maximum local sine of the azimuthal angle
68 const Double_t AliTRDtrackerV1::fgkMaxStep = 2.0; // Maximal step size in propagation
69 Double_t AliTRDtrackerV1::fgTopologicQA[kNConfigs] = {
70 0.5112, 0.5112, 0.5112, 0.0786, 0.0786,
71 0.0786, 0.0786, 0.0579, 0.0579, 0.0474,
72 0.0474, 0.0408, 0.0335, 0.0335, 0.0335
74 const Double_t AliTRDtrackerV1::fgkX0[kNPlanes] = {
75 300.2, 312.8, 325.4, 338.0, 350.6, 363.2};
76 Int_t AliTRDtrackerV1::fgNTimeBins = 0;
77 AliRieman* AliTRDtrackerV1::fgRieman = NULL;
78 TLinearFitter* AliTRDtrackerV1::fgTiltedRieman = NULL;
79 TLinearFitter* AliTRDtrackerV1::fgTiltedRiemanConstrained = NULL;
81 //____________________________________________________________________
82 AliTRDtrackerV1::AliTRDtrackerV1(AliTRDReconstructor *rec)
84 ,fkReconstructor(NULL)
94 // Default constructor.
97 SetReconstructor(rec); // initialize reconstructor
99 // initialize geometry
100 if(!AliGeomManager::GetGeometry()){
101 AliFatal("Could not get geometry.");
103 fGeom = new AliTRDgeometry();
104 fGeom->CreateClusterMatrixArray();
105 TGeoHMatrix *matrix = NULL;
106 Double_t loc[] = {0., 0., 0.};
107 Double_t glb[] = {0., 0., 0.};
108 for(Int_t ily=kNPlanes; ily--;){
110 while(!(matrix = fGeom->GetClusterMatrix(AliTRDgeometry::GetDetector(ily, 2, ism)))) ism++;
112 AliError(Form("Could not get transformation matrix for layer %d. Use default.", ily));
113 fR[ily] = fgkX0[ily];
116 matrix->LocalToMaster(loc, glb);
117 fR[ily] = glb[0]+ AliTRDgeometry::AnodePos()-.5*AliTRDgeometry::AmThick() - AliTRDgeometry::DrThick();
120 // initialize cluster containers
121 for (Int_t isector = 0; isector < AliTRDgeometry::kNsector; isector++) new(&fTrSec[isector]) AliTRDtrackingSector(fGeom, isector);
124 memset(fTrackQuality, 0, kMaxTracksStack*sizeof(Double_t));
125 memset(fSeedLayer, 0, kMaxTracksStack*sizeof(Int_t));
126 memset(fSeedTB, 0, kNSeedPlanes*sizeof(AliTRDchamberTimeBin*));
127 fTracksESD = new TClonesArray("AliESDtrack", 2*kMaxTracksStack);
128 fTracksESD->SetOwner();
131 //____________________________________________________________________
132 AliTRDtrackerV1::~AliTRDtrackerV1()
138 if(fgRieman) delete fgRieman; fgRieman = NULL;
139 if(fgTiltedRieman) delete fgTiltedRieman; fgTiltedRieman = NULL;
140 if(fgTiltedRiemanConstrained) delete fgTiltedRiemanConstrained; fgTiltedRiemanConstrained = NULL;
141 for(Int_t isl =0; isl<kNSeedPlanes; isl++) if(fSeedTB[isl]) delete fSeedTB[isl];
142 if(fTracksESD){ fTracksESD->Delete(); delete fTracksESD; }
143 if(fTracks) {fTracks->Delete(); delete fTracks;}
144 if(fTracklets) {fTracklets->Delete(); delete fTracklets;}
146 fClusters->Delete(); delete fClusters;
148 if(fGeom) delete fGeom;
151 //____________________________________________________________________
152 Int_t AliTRDtrackerV1::Clusters2Tracks(AliESDEvent *esd)
155 // Steering stand alone tracking for full TRD detector
158 // esd : The ESD event. On output it contains
159 // the ESD tracks found in TRD.
162 // Number of tracks found in the TRD detector.
164 // Detailed description
165 // 1. Launch individual SM trackers.
166 // See AliTRDtrackerV1::Clusters2TracksSM() for details.
170 AliError("Reconstruction configuration not initialized. Call first AliTRDReconstructor::SetRecoParam().");
174 //AliInfo("Start Track Finder ...");
176 for(int ism=0; ism<AliTRDgeometry::kNsector; ism++){
177 // for(int ism=1; ism<2; ism++){
178 //AliInfo(Form("Processing supermodule %i ...", ism));
179 ntracks += Clusters2TracksSM(ism, esd);
181 AliInfo(Form("Number of tracks: !TRDin[%d]", ntracks));
186 //_____________________________________________________________________________
187 Bool_t AliTRDtrackerV1::GetTrackPoint(Int_t index, AliTrackPoint &p) const
189 //AliInfo(Form("Asking for tracklet %d", index));
191 // reset position of the point before using it
192 p.SetXYZ(0., 0., 0.);
193 AliTRDseedV1 *tracklet = GetTracklet(index);
194 if (!tracklet) return kFALSE;
196 // get detector for this tracklet
197 Int_t det = tracklet->GetDetector();
198 Int_t sec = fGeom->GetSector(det);
199 Double_t alpha = (sec+.5)*AliTRDgeometry::GetAlpha(),
200 sinA = TMath::Sin(alpha),
201 cosA = TMath::Cos(alpha);
203 local[0] = tracklet->GetX();
204 local[1] = tracklet->GetY();
205 local[2] = tracklet->GetZ();
207 fGeom->RotateBack(det, local, global);
209 Double_t cov2D[3]; Float_t cov[6];
210 tracklet->GetCovAt(local[0], cov2D);
211 cov[0] = cov2D[0]*sinA*sinA;
212 cov[1] =-cov2D[0]*sinA*cosA;
213 cov[2] =-cov2D[1]*sinA;
214 cov[3] = cov2D[0]*cosA*cosA;
215 cov[4] = cov2D[1]*cosA;
217 // store the global position of the tracklet and its covariance matrix in the track point
218 p.SetXYZ(global[0],global[1],global[2], cov);
221 AliGeomManager::ELayerID iLayer = AliGeomManager::ELayerID(AliGeomManager::kTRD1+fGeom->GetLayer(det));
222 Int_t modId = fGeom->GetSector(det) * AliTRDgeometry::kNstack + fGeom->GetStack(det);
223 UShort_t volid = AliGeomManager::LayerToVolUID(iLayer, modId);
224 p.SetVolumeID(volid);
229 //____________________________________________________________________
230 TLinearFitter* AliTRDtrackerV1::GetTiltedRiemanFitter()
232 if(!fgTiltedRieman) fgTiltedRieman = new TLinearFitter(4, "hyp4");
233 return fgTiltedRieman;
236 //____________________________________________________________________
237 TLinearFitter* AliTRDtrackerV1::GetTiltedRiemanFitterConstraint()
239 if(!fgTiltedRiemanConstrained) fgTiltedRiemanConstrained = new TLinearFitter(2, "hyp2");
240 return fgTiltedRiemanConstrained;
243 //____________________________________________________________________
244 AliRieman* AliTRDtrackerV1::GetRiemanFitter()
246 if(!fgRieman) fgRieman = new AliRieman(AliTRDseedV1::kNtb * AliTRDgeometry::kNlayer);
250 //_____________________________________________________________________________
251 Int_t AliTRDtrackerV1::PropagateBack(AliESDEvent *event)
253 // Propagation of ESD tracks from TPC to TOF detectors and building of the TRD track. For building
254 // a TRD track an ESD track is used as seed. The informations obtained on the TRD track (measured points,
255 // covariance, PID, etc.) are than used to update the corresponding ESD track.
256 // Each track seed is first propagated to the geometrical limit of the TRD detector.
257 // Its prolongation is searched in the TRD and if corresponding clusters are found tracklets are
258 // constructed out of them (see AliTRDseedV1::AttachClusters()) and the track is updated.
259 // Otherwise the ESD track is left unchanged.
261 // The following steps are performed:
262 // 1. Selection of tracks based on the variance in the y-z plane.
263 // 2. Propagation to the geometrical limit of the TRD volume. If track propagation fails the AliESDtrack::kTRDStop is set.
264 // 3. Prolongation inside the fiducial volume (see AliTRDtrackerV1::FollowBackProlongation()) and marking
265 // the following status bits:
266 // - AliESDtrack::kTRDin - if the tracks enters the TRD fiducial volume
267 // - AliESDtrack::kTRDStop - if the tracks fails propagation
268 // - AliESDtrack::kTRDbackup - if the tracks fulfills chi2 conditions and qualify for refitting
269 // 4. Writting to friends, PID, MC label, quality etc. Setting status bit AliESDtrack::kTRDout.
270 // 5. Propagation to TOF. If track propagation fails the AliESDtrack::kTRDStop is set.
273 if(!fClusters || !fClusters->GetEntriesFast()){
274 AliInfo("No TRD clusters");
277 AliTRDCalibraFillHisto *calibra = AliTRDCalibraFillHisto::Instance(); // Calibration monitor
278 if (!calibra) AliInfo("Could not get Calibra instance");
279 if (!fgNTimeBins) fgNTimeBins = fkReconstructor->GetNTimeBins();
282 Int_t nFound = 0, // number of tracks found
283 nBacked = 0, // number of tracks backed up for refit
284 nSeeds = 0, // total number of ESD seeds
285 nTRDseeds= 0, // number of seeds in the TRD acceptance
286 nTPCseeds= 0; // number of TPC seeds
287 Float_t foundMin = 20.0;
289 Float_t *quality = NULL;
291 nSeeds = event->GetNumberOfTracks();
292 // Sort tracks according to quality
293 // (covariance in the yz plane)
295 quality = new Float_t[nSeeds];
296 index = new Int_t[4*nSeeds];
297 for (Int_t iSeed = nSeeds; iSeed--;) {
298 AliESDtrack *seed = event->GetTrack(iSeed);
299 Double_t covariance[15];
300 seed->GetExternalCovariance(covariance);
301 quality[iSeed] = covariance[0] + covariance[2];
303 TMath::Sort(nSeeds, quality, index,kFALSE);
306 // Propagate all seeds
309 for (Int_t iSeed = 0; iSeed < nSeeds; iSeed++) {
311 // Get the seeds in sorted sequence
312 AliESDtrack *seed = event->GetTrack(index[iSeed]);
313 Float_t p4 = seed->GetC(seed->GetBz());
315 // Check the seed status
316 ULong_t status = seed->GetStatus();
317 if ((status & AliESDtrack::kTPCout) == 0) continue;
318 if ((status & AliESDtrack::kTRDout) != 0) continue;
320 // Propagate to the entrance in the TRD mother volume
321 track.~AliTRDtrackV1();
322 new(&track) AliTRDtrackV1(*seed);
323 if(AliTRDgeometry::GetXtrdBeg() > (fgkMaxStep + track.GetX()) && !PropagateToX(track, AliTRDgeometry::GetXtrdBeg(), fgkMaxStep)){
324 seed->UpdateTrackParams(&track, AliESDtrack::kTRDStop);
327 if(!AdjustSector(&track)){
328 seed->UpdateTrackParams(&track, AliESDtrack::kTRDStop);
331 if(TMath::Abs(track.GetSnp()) > fgkMaxSnp) {
332 seed->UpdateTrackParams(&track, AliESDtrack::kTRDStop);
336 AliDebug(2, Form("TRD propagate TPC seed[%d] = %d.", iSeed, index[iSeed]));
337 // store track status at TRD entrance
338 seed->UpdateTrackParams(&track, AliESDtrack::kTRDbackup);
340 // prepare track and do propagation in the TRD
341 track.SetReconstructor(fkReconstructor);
342 track.SetKink(Bool_t(seed->GetKinkIndex(0)));
343 track.SetPrimary(status & AliESDtrack::kTPCin);
344 expectedClr = FollowBackProlongation(track);
345 // check if track entered the TRD fiducial volume
346 if(track.GetTrackIn()){
347 seed->UpdateTrackParams(&track, AliESDtrack::kTRDin);
350 // check if track was stopped in the TRD
352 seed->UpdateTrackParams(&track, AliESDtrack::kTRDStop);
358 // computes PID for track
360 // update calibration references using this track
361 if(calibra->GetHisto2d()) calibra->UpdateHistogramsV1(&track);
362 // save calibration object
363 if (fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) > 0) {
364 AliTRDtrackV1 *calibTrack = new AliTRDtrackV1(track);
365 calibTrack->SetOwner();
366 seed->AddCalibObject(calibTrack);
369 seed->UpdateTrackParams(&track, AliESDtrack::kTRDout);
370 track.UpdateESDtrack(seed);
373 if ((TMath::Abs(track.GetC(track.GetBz()) - p4) / TMath::Abs(p4) < 0.2) ||(track.Pt() > 0.8)) {
375 // Make backup for back propagation
376 Int_t foundClr = track.GetNumberOfClusters();
377 if (foundClr >= foundMin) {
378 track.CookLabel(1. - fgkLabelFraction);
379 //if(track.GetBackupTrack()) UseClusters(track.GetBackupTrack());
381 // Sign only gold tracks
382 if (track.GetChi2() / track.GetNumberOfClusters() < 4) {
383 //if ((seed->GetKinkIndex(0) == 0) && (track.Pt() < 1.5)) UseClusters(&track);
385 Bool_t isGold = kFALSE;
388 if (track.GetChi2() / track.GetNumberOfClusters() < 5) {
389 if (track.GetBackupTrack()) seed->UpdateTrackParams(track.GetBackupTrack(),AliESDtrack::kTRDbackup);
395 if ((!isGold) && (track.GetNCross() == 0) && (track.GetChi2() / track.GetNumberOfClusters() < 7)) {
396 //seed->UpdateTrackParams(track, AliESDtrack::kTRDbackup);
397 if (track.GetBackupTrack()) seed->UpdateTrackParams(track.GetBackupTrack(),AliESDtrack::kTRDbackup);
402 if ((!isGold) && (track.GetBackupTrack())) {
403 if ((track.GetBackupTrack()->GetNumberOfClusters() > foundMin) && ((track.GetBackupTrack()->GetChi2()/(track.GetBackupTrack()->GetNumberOfClusters()+1)) < 7)) {
404 seed->UpdateTrackParams(track.GetBackupTrack(),AliESDtrack::kTRDbackup);
412 // Propagation to the TOF
413 if(!(seed->GetStatus()&AliESDtrack::kTRDStop)) {
414 Int_t sm = track.GetSector();
415 // default value in case we have problems with the geometry.
416 Double_t xtof = 371.;
417 //Calculate radial position of the beginning of the TOF
418 //mother volume. In order to avoid mixing of the TRD
419 //and TOF modules some hard values are needed. This are:
420 //1. The path to the TOF module.
421 //2. The width of the TOF (29.05 cm)
422 //(with the help of Annalisa de Caro Mar-17-2009)
424 gGeoManager->cd(Form("/ALIC_1/B077_1/BSEGMO%d_1/BTOF%d_1", sm, sm));
425 TGeoHMatrix *m = NULL;
426 Double_t loc[]={0., 0., -.5*29.05}, glob[3];
428 if((m=gGeoManager->GetCurrentMatrix())){
429 m->LocalToMaster(loc, glob);
430 xtof = TMath::Sqrt(glob[0]*glob[0]+glob[1]*glob[1]);
433 if(xtof > (fgkMaxStep + track.GetX()) && !PropagateToX(track, xtof, fgkMaxStep)){
434 seed->UpdateTrackParams(&track, AliESDtrack::kTRDStop);
437 if(!AdjustSector(&track)){
438 seed->UpdateTrackParams(&track, AliESDtrack::kTRDStop);
441 if(TMath::Abs(track.GetSnp()) > fgkMaxSnp){
442 seed->UpdateTrackParams(&track, AliESDtrack::kTRDStop);
445 //seed->UpdateTrackParams(&track, AliESDtrack::kTRDout);
446 // TODO obsolete - delete
447 seed->SetTRDQuality(track.StatusForTOF());
449 seed->SetTRDBudget(track.GetBudget(0));
451 if(index) delete [] index;
452 if(quality) delete [] quality;
454 AliInfo(Form("Number of seeds: TPCout[%d] TRDin[%d]", nTPCseeds, nTRDseeds));
455 AliInfo(Form("Number of tracks: TRDout[%d] TRDbackup[%d]", nFound, nBacked));
457 // run stand alone tracking
458 if (fkReconstructor->IsSeeding()) Clusters2Tracks(event);
464 //____________________________________________________________________
465 Int_t AliTRDtrackerV1::RefitInward(AliESDEvent *event)
468 // Refits tracks within the TRD. The ESD event is expected to contain seeds
469 // at the outer part of the TRD.
470 // The tracks are propagated to the innermost time bin
471 // of the TRD and the ESD event is updated
472 // Origin: Thomas KUHR (Thomas.Kuhr@cern.ch)
475 Int_t nseed = 0; // contor for loaded seeds
476 Int_t found = 0; // contor for updated TRD tracks
479 if(!fClusters || !fClusters->GetEntriesFast()){
480 AliInfo("No TRD clusters");
484 for (Int_t itrack = 0; itrack < event->GetNumberOfTracks(); itrack++) {
485 AliESDtrack *seed = event->GetTrack(itrack);
486 ULong_t status = seed->GetStatus();
488 new(&track) AliTRDtrackV1(*seed);
489 if (track.GetX() < 270.0) {
490 seed->UpdateTrackParams(&track, AliESDtrack::kTRDbackup);
494 // reject tracks which failed propagation in the TRD or
495 // are produced by the TRD stand alone tracker
496 if(!(status & AliESDtrack::kTRDout)) continue;
497 if(!(status & AliESDtrack::kTRDin)) continue;
500 track.ResetCovariance(50.0);
502 // do the propagation and processing
503 Bool_t kUPDATE = kFALSE;
504 Double_t xTPC = 250.0;
505 if(FollowProlongation(track)){
506 // Update the friend track
507 if (fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) > 0){
508 TObject *o = NULL; Int_t ic = 0;
509 AliTRDtrackV1 *calibTrack = NULL;
510 while((o = seed->GetCalibObject(ic++))){
511 if(!(calibTrack = dynamic_cast<AliTRDtrackV1*>(o))) continue;
512 calibTrack->SetTrackOut(&track);
517 if (PropagateToX(track, xTPC, fgkMaxStep)) { // -with update
518 seed->UpdateTrackParams(&track, AliESDtrack::kTRDrefit);
524 // Prolongate to TPC without update
526 AliTRDtrackV1 tt(*seed);
527 if (PropagateToX(tt, xTPC, fgkMaxStep)) seed->UpdateTrackParams(&tt, AliESDtrack::kTRDbackup);
530 AliInfo(Form("Number of seeds: TRDout[%d]", nseed));
531 AliInfo(Form("Number of tracks: TRDrefit[%d]", found));
536 //____________________________________________________________________
537 Int_t AliTRDtrackerV1::FollowProlongation(AliTRDtrackV1 &t)
539 // Extrapolates the TRD track in the TPC direction.
542 // t : the TRD track which has to be extrapolated
545 // number of clusters attached to the track
547 // Detailed description
549 // Starting from current radial position of track <t> this function
550 // extrapolates the track through the 6 TRD layers. The following steps
551 // are being performed for each plane:
553 // a. get plane limits in the local x direction
554 // b. check crossing sectors
555 // c. check track inclination
556 // 2. search tracklet in the tracker list (see GetTracklet() for details)
557 // 3. evaluate material budget using the geo manager
558 // 4. propagate and update track using the tracklet information.
563 Int_t nClustersExpected = 0;
564 for (Int_t iplane = kNPlanes; iplane--;) {
566 AliTRDseedV1 *tracklet = GetTracklet(&t, iplane, index);
567 AliDebug(2, Form("Tracklet[%p] ly[%d] idx[%d]", (void*)tracklet, iplane, index));
568 if(!tracklet) continue;
569 if(!tracklet->IsOK()){
570 AliDebug(1, Form("Tracklet Det[%d] !OK", tracklet->GetDetector()));
573 Double_t x = tracklet->GetX();//GetX0();
574 // reject tracklets which are not considered for inward refit
575 if(x > t.GetX()+fgkMaxStep) continue;
577 // append tracklet to track
578 t.SetTracklet(tracklet, index);
580 if (x < (t.GetX()-fgkMaxStep) && !PropagateToX(t, x+fgkMaxStep, fgkMaxStep)) break;
581 if (!AdjustSector(&t)) break;
583 // Start global position
587 // End global position
588 Double_t alpha = t.GetAlpha(), y, z;
589 if (!t.GetProlongation(x,y,z)) break;
591 xyz1[0] = x * TMath::Cos(alpha) - y * TMath::Sin(alpha);
592 xyz1[1] = x * TMath::Sin(alpha) + y * TMath::Cos(alpha);
595 Double_t length = TMath::Sqrt(
596 (xyz0[0]-xyz1[0])*(xyz0[0]-xyz1[0]) +
597 (xyz0[1]-xyz1[1])*(xyz0[1]-xyz1[1]) +
598 (xyz0[2]-xyz1[2])*(xyz0[2]-xyz1[2])
601 // Get material budget
603 if(AliTracker::MeanMaterialBudget(xyz0, xyz1, param)<=0.) break;
604 Double_t xrho= param[0]*param[4];
605 Double_t xx0 = param[1]; // Get mean propagation parameters
607 // Propagate and update
608 t.PropagateTo(x, xx0, xrho);
609 if (!AdjustSector(&t)) break;
612 Double_t cov[3]; tracklet->GetCovAt(x, cov);
613 Double_t p[2] = { tracklet->GetY(), tracklet->GetZ()};
614 Double_t chi2 = ((AliExternalTrackParam)t).GetPredictedChi2(p, cov);
615 if (chi2 < 1e+10 && ((AliExternalTrackParam&)t).Update(p, cov)){
616 // Register info to track
617 t.SetNumberOfClusters();
619 nClustersExpected += tracklet->GetN();
623 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) > 1){
625 for(int iplane=0; iplane<AliTRDgeometry::kNlayer; iplane++){
626 AliTRDseedV1 *tracklet = GetTracklet(&t, iplane, index);
627 if(!tracklet) continue;
628 t.SetTracklet(tracklet, index);
631 if(fkReconstructor->IsDebugStreaming()){
632 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
633 TTreeSRedirector &cstreamer = *fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker);
634 AliTRDtrackV1 track(t);
636 cstreamer << "FollowProlongation"
637 << "EventNumber=" << eventNumber
638 << "ncl=" << nClustersExpected
639 << "track.=" << &track
643 return nClustersExpected;
647 //_____________________________________________________________________________
648 Int_t AliTRDtrackerV1::FollowBackProlongation(AliTRDtrackV1 &t)
650 // Extrapolates/Build the TRD track in the TOF direction.
653 // t : the TRD track which has to be extrapolated
656 // number of clusters attached to the track
658 // Starting from current radial position of track <t> this function
659 // extrapolates the track through the 6 TRD layers. The following steps
660 // are being performed for each plane:
661 // 1. Propagate track to the entrance of the next chamber:
662 // - get chamber limits in the radial direction
663 // - check crossing sectors
664 // - check track inclination
665 // - check track prolongation against boundary conditions (see exclusion boundaries on AliTRDgeometry::IsOnBoundary())
666 // 2. Build tracklet (see AliTRDseed::AttachClusters() for details) for this layer if needed. If only
667 // Kalman filter is needed and tracklets are already linked to the track this step is skipped.
668 // 3. Fit tracklet using the information from the Kalman filter.
669 // 4. Propagate and update track at reference radial position of the tracklet.
670 // 5. Register tracklet with the tracker and track; update pulls monitoring.
673 // 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:
674 // - AliTRDtrackV1::kProlongation : track prolongation failed
675 // - AliTRDtrackV1::kPropagation : track prolongation failed
676 // - AliTRDtrackV1::kAdjustSector : failed during sector crossing
677 // - AliTRDtrackV1::kSnp : too large bending
678 // - AliTRDtrackV1::kTrackletInit : fail to initialize tracklet
679 // - AliTRDtrackV1::kUpdate : fail to attach clusters or fit the tracklet
680 // - AliTRDtrackV1::kUnknown : anything which is not covered before
681 // 2. By default the status of the track before first TRD update is saved.
686 // Alexandru Bercuci <A.Bercuci@gsi.de>
690 Double_t driftLength = .5*AliTRDgeometry::AmThick() + AliTRDgeometry::DrThick();
691 AliTRDtrackingChamber *chamber = NULL;
693 Int_t debugLevel = fkReconstructor->IsDebugStreaming() ? fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) : 0;
694 TTreeSRedirector *cstreamer = fkReconstructor->IsDebugStreaming() ? fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker) : 0x0;
696 Bool_t kStoreIn(kTRUE), // toggel store track params. at TRD entry
697 kStandAlone(kFALSE), // toggle tracker awarness of stand alone seeding
698 kUseTRD(fkRecoParam->IsOverPtThreshold(t.Pt()));// use TRD measurment to update Kalman
701 AliTRDseedV1 tracklet, *ptrTracklet = NULL;
702 // Special case for stand alone tracking
703 // - store all tracklets found by seeding
704 // - start propagation from first tracklet found
705 AliTRDseedV1 *tracklets[kNPlanes];
706 memset(tracklets, 0, sizeof(AliTRDseedV1 *) * kNPlanes);
707 for(Int_t ip(kNPlanes); ip--;){
708 if(!(tracklets[ip] = t.GetTracklet(ip))) continue;
710 if(tracklets[ip]->IsOK()) startLayer=ip;
714 AliDebug(4, Form("SA[%c] Start[%d]\n"
715 " [0]idx[%d] traklet[%p]\n"
716 " [1]idx[%d] traklet[%p]\n"
717 " [2]idx[%d] traklet[%p]\n"
718 " [3]idx[%d] traklet[%p]\n"
719 " [4]idx[%d] traklet[%p]\n"
720 " [5]idx[%d] traklet[%p]"
721 , kStandAlone?'y':'n', startLayer
722 , t.GetTrackletIndex(0), (void*)tracklets[0]
723 , t.GetTrackletIndex(1), (void*)tracklets[1]
724 , t.GetTrackletIndex(2), (void*)tracklets[2]
725 , t.GetTrackletIndex(3), (void*)tracklets[3]
726 , t.GetTrackletIndex(4), (void*)tracklets[4]
727 , t.GetTrackletIndex(5), (void*)tracklets[5]));
729 // Loop through the TRD layers
730 TGeoHMatrix *matrix = NULL;
732 for (Int_t ily=startLayer, sm=-1, stk=-1, det=-1; ily < AliTRDgeometry::kNlayer; ily++) {
733 AliDebug(2, Form("Propagate to x[%d] = %7.2f", ily, fR[ily]));
735 // rough estimate of the entry point
736 if (!t.GetProlongation(fR[ily], y, z)){
738 t.SetStatus(AliTRDtrackV1::kProlongation);
739 AliDebug(4, Form("Failed Rough Prolongation to ly[%d] x[%7.2f] y[%7.2f] z[%7.2f]", ily, fR[ily], y, z));
743 // find sector / stack / detector
745 // TODO cross check with y value !
746 stk = fGeom->GetStack(z, ily);
747 det = stk>=0 ? AliTRDgeometry::GetDetector(ily, stk, sm) : -1;
748 matrix = det>=0 ? fGeom->GetClusterMatrix(det) : NULL;
749 AliDebug(3, Form("Propagate to det[%3d]", det));
751 // check if supermodule/chamber is installed
752 if( !fGeom->GetSMstatus(sm) ||
754 fGeom->IsHole(ily, stk, sm) ||
756 AliDebug(4, Form("Missing Geometry ly[%d]. Guess radial position", ily));
757 // propagate to the default radial position
758 if(fR[ily] > (fgkMaxStep + t.GetX()) && !PropagateToX(t, fR[ily], fgkMaxStep)){
760 t.SetStatus(AliTRDtrackV1::kPropagation);
761 AliDebug(4, "Failed Propagation [Missing Geometry]");
764 if(!AdjustSector(&t)){
766 t.SetStatus(AliTRDtrackV1::kAdjustSector);
767 AliDebug(4, "Failed Adjust Sector [Missing Geometry]");
770 if(TMath::Abs(t.GetSnp()) > fgkMaxSnp){
772 t.SetStatus(AliTRDtrackV1::kSnp);
773 AliDebug(4, "Failed Max Snp [Missing Geometry]");
776 t.SetStatus(AliTRDtrackV1::kGeometry, ily);
780 // retrieve rotation matrix for the current chamber
781 Double_t loc[] = {AliTRDgeometry::AnodePos()- driftLength, 0., 0.};
782 Double_t glb[] = {0., 0., 0.};
783 matrix->LocalToMaster(loc, glb);
785 // Propagate to the radial distance of the current layer
786 x = glb[0] - fgkMaxStep;
787 if(x > (fgkMaxStep + t.GetX()) && !PropagateToX(t, x, fgkMaxStep)){
789 t.SetStatus(AliTRDtrackV1::kPropagation);
790 AliDebug(4, Form("Failed Initial Propagation to x[%7.2f]", x));
793 if(!AdjustSector(&t)){
795 t.SetStatus(AliTRDtrackV1::kAdjustSector);
796 AliDebug(4, "Failed Adjust Sector Start");
799 if(TMath::Abs(t.GetSnp()) > fgkMaxSnp) {
801 t.SetStatus(AliTRDtrackV1::kSnp);
802 AliDebug(4, Form("Failed Max Snp[%f] MaxSnp[%f]", t.GetSnp(), fgkMaxSnp));
805 Bool_t doRecalculate = kFALSE;
806 if(sm != t.GetSector()){
808 doRecalculate = kTRUE;
810 if(stk != fGeom->GetStack(z, ily)){
811 stk = fGeom->GetStack(z, ily);
812 doRecalculate = kTRUE;
815 det = AliTRDgeometry::GetDetector(ily, stk, sm);
816 if(!(matrix = fGeom->GetClusterMatrix(det))){
817 t.SetStatus(AliTRDtrackV1::kGeometry, ily);
818 AliDebug(4, Form("Failed Geometry Matrix ly[%d]", ily));
821 matrix->LocalToMaster(loc, glb);
822 x = glb[0] - fgkMaxStep;
825 // check if track is well inside fiducial volume
826 if (!t.GetProlongation(x+fgkMaxStep, y, z)) {
828 t.SetStatus(AliTRDtrackV1::kProlongation);
829 AliDebug(4, Form("Failed Prolongation to x[%7.2f] y[%7.2f] z[%7.2f]", x+fgkMaxStep, y, z));
832 if(fGeom->IsOnBoundary(det, y, z, .5)){
833 t.SetStatus(AliTRDtrackV1::kBoundary, ily);
834 AliDebug(4, "Failed Track on Boundary");
837 // mark track as entering the FIDUCIAL volume of TRD
843 ptrTracklet = tracklets[ily];
844 if(!ptrTracklet){ // BUILD TRACKLET
845 AliDebug(3, Form("Building tracklet det[%d]", det));
846 // check data in supermodule
847 if(!fTrSec[sm].GetNChambers()){
848 t.SetStatus(AliTRDtrackV1::kNoClusters, ily);
849 AliDebug(4, "Failed NoClusters");
852 if(fTrSec[sm].GetX(ily) < 1.){
853 t.SetStatus(AliTRDtrackV1::kNoClusters, ily);
854 AliDebug(4, "Failed NoX");
858 // check data in chamber
859 if(!(chamber = fTrSec[sm].GetChamber(stk, ily))){
860 t.SetStatus(AliTRDtrackV1::kNoClusters, ily);
861 AliDebug(4, "Failed No Detector");
864 if(chamber->GetNClusters() < fgNTimeBins*fkRecoParam ->GetFindableClusters()){
865 t.SetStatus(AliTRDtrackV1::kNoClusters, ily);
866 AliDebug(4, "Failed Not Enough Clusters in Detector");
870 tracklet.~AliTRDseedV1();
871 ptrTracklet = new(&tracklet) AliTRDseedV1(det);
872 ptrTracklet->SetReconstructor(fkReconstructor);
873 ptrTracklet->SetKink(t.IsKink());
874 ptrTracklet->SetPrimary(t.IsPrimary());
875 ptrTracklet->SetPadPlane(fGeom->GetPadPlane(ily, stk));
876 ptrTracklet->SetX0(glb[0]+driftLength);
877 if(!ptrTracklet->Init(&t)){
879 t.SetStatus(AliTRDtrackV1::kTrackletInit);
880 AliDebug(4, "Failed Tracklet Init");
883 if(!ptrTracklet->AttachClusters(chamber, kTRUE)){
884 t.SetStatus(AliTRDtrackV1::kNoAttach, ily);
886 AliTRDseedV1 trackletCp(*ptrTracklet);
887 UChar_t status(t.GetStatusTRD(ily));
888 (*cstreamer) << "FollowBackProlongation2"
889 <<"status=" << status
890 <<"tracklet.=" << &trackletCp
893 AliDebug(4, "Failed Attach Clusters");
896 AliDebug(3, Form("Number of Clusters in Tracklet: %d", ptrTracklet->GetN()));
897 if(ptrTracklet->GetN() < fgNTimeBins*fkRecoParam->GetFindableClusters()){
898 t.SetStatus(AliTRDtrackV1::kNoClustersTracklet, ily);
900 AliTRDseedV1 trackletCp(*ptrTracklet);
901 UChar_t status(t.GetStatusTRD(ily));
902 (*cstreamer) << "FollowBackProlongation2"
903 <<"status=" << status
904 <<"tracklet.=" << &trackletCp
907 AliDebug(4, "Failed N Clusters Attached");
910 ptrTracklet->UpdateUsed();
911 } else AliDebug(2, Form("Use external tracklet ly[%d]", ily));
912 // propagate track to the radial position of the tracklet
915 // tilt correction options
917 // 2 : pseudo tilt correction
918 if(!ptrTracklet->Fit(2)){
919 t.SetStatus(AliTRDtrackV1::kNoFit, ily);
920 AliDebug(4, "Failed Tracklet Fit");
923 x = ptrTracklet->GetX(); //GetX0();
924 if(x > (fgkMaxStep + t.GetX()) && !PropagateToX(t, x, fgkMaxStep)) {
926 t.SetStatus(AliTRDtrackV1::kPropagation);
927 AliDebug(4, Form("Failed Propagation to Tracklet x[%7.2f]", x));
930 if(!AdjustSector(&t)) {
932 t.SetStatus(AliTRDtrackV1::kAdjustSector);
933 AliDebug(4, "Failed Adjust Sector");
936 if(TMath::Abs(t.GetSnp()) > fgkMaxSnp) {
938 t.SetStatus(AliTRDtrackV1::kSnp);
939 AliDebug(4, Form("Failed Max Snp[%f] MaxSnp[%f]", t.GetSnp(), fgkMaxSnp));
942 Double_t cov[3]; ptrTracklet->GetCovAt(x, cov);
943 Double_t p[2] = { ptrTracklet->GetY(), ptrTracklet->GetZ()};
944 Double_t chi2 = ((AliExternalTrackParam)t).GetPredictedChi2(p, cov);
945 // update Kalman with the TRD measurement
946 if(chi2>1e+10){ // TODO
947 t.SetStatus(AliTRDtrackV1::kChi2, ily);
949 UChar_t status(t.GetStatusTRD());
950 AliTRDseedV1 trackletCp(*ptrTracklet);
951 AliTRDtrackV1 trackCp(t);
953 (*cstreamer) << "FollowBackProlongation1"
954 << "status=" << status
955 << "tracklet.=" << &trackletCp
956 << "track.=" << &trackCp
959 AliDebug(4, Form("Failed Chi2[%f]", chi2));
963 if(!((AliExternalTrackParam&)t).Update(p, cov)) {
965 t.SetStatus(AliTRDtrackV1::kUpdate);
967 UChar_t status(t.GetStatusTRD());
968 AliTRDseedV1 trackletCp(*ptrTracklet);
969 AliTRDtrackV1 trackCp(t);
971 (*cstreamer) << "FollowBackProlongation1"
972 << "status=" << status
973 << "tracklet.=" << &trackletCp
974 << "track.=" << &trackCp
977 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]));
981 if(!kStandAlone) ptrTracklet->UseClusters();
983 AliTracker::FillResiduals(&t, p, cov, ptrTracklet->GetVolumeId());
986 // register tracklet with the tracker and track
987 ptrTracklet->Update(&t);
988 ptrTracklet = SetTracklet(ptrTracklet);
989 Int_t index(fTracklets->GetEntriesFast()-1);
990 t.SetTracklet(ptrTracklet, index);
991 // Register info to track
992 t.SetNumberOfClusters();
995 n += ptrTracklet->GetN();
996 AliDebug(2, Form("Setting Tracklet[%d] @ Idx[%d]", ily, index));
998 // Reset material budget if 2 consecutive gold
999 // if(ilayer>0 && t.GetTracklet(ilayer-1) && ptrTracklet->GetN() + t.GetTracklet(ilayer-1)->GetN() > 20) t.SetBudget(2, 0.);
1001 // Make backup of the track until is gold
1003 if(!kStandAlone && (failed = t.MakeBackupTrack())) AliDebug(2, Form("Failed backup on cut[%d]", failed));
1005 } // end layers loop
1006 //printf("clusters[%d] chi2[%f] x[%f] status[%d ", n, t.GetChi2(), t.GetX(), t.GetStatusTRD());
1007 //for(int i=0; i<6; i++) printf("%d ", t.GetStatusTRD(i)); printf("]\n");
1010 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
1011 AliTRDtrackV1 track(t);
1013 (*cstreamer) << "FollowBackProlongation0"
1014 << "EventNumber=" << eventNumber
1016 << "track.=" << &track
1023 //_________________________________________________________________________
1024 Float_t AliTRDtrackerV1::FitRieman(AliTRDseedV1 *tracklets, Double_t *chi2, Int_t *const planes){
1026 // Fits a Riemann-circle to the given points without tilting pad correction.
1027 // The fit is performed using an instance of the class AliRieman (equations
1028 // and transformations see documentation of this class)
1029 // Afterwards all the tracklets are Updated
1031 // Parameters: - Array of tracklets (AliTRDseedV1)
1032 // - Storage for the chi2 values (beginning with direction z)
1033 // - Seeding configuration
1034 // Output: - The curvature
1036 AliRieman *fitter = AliTRDtrackerV1::GetRiemanFitter();
1038 Int_t allplanes[] = {0, 1, 2, 3, 4, 5};
1039 Int_t *ppl = &allplanes[0];
1040 Int_t maxLayers = 6;
1045 for(Int_t il = 0; il < maxLayers; il++){
1046 if(!tracklets[ppl[il]].IsOK()) continue;
1047 fitter->AddPoint(tracklets[ppl[il]].GetX0(), tracklets[ppl[il]].GetYfit(0), tracklets[ppl[il]].GetZfit(0),1,10);
1050 // Set the reference position of the fit and calculate the chi2 values
1051 memset(chi2, 0, sizeof(Double_t) * 2);
1052 for(Int_t il = 0; il < maxLayers; il++){
1053 // Reference positions
1054 tracklets[ppl[il]].Init(fitter);
1057 if((!tracklets[ppl[il]].IsOK()) && (!planes)) continue;
1058 chi2[0] += tracklets[ppl[il]].GetChi2Y();
1059 chi2[1] += tracklets[ppl[il]].GetChi2Z();
1061 return fitter->GetC();
1064 //_________________________________________________________________________
1065 void AliTRDtrackerV1::FitRieman(AliTRDcluster **seedcl, Double_t chi2[2])
1068 // Performs a Riemann helix fit using the seedclusters as spacepoints
1069 // Afterwards the chi2 values are calculated and the seeds are updated
1071 // Parameters: - The four seedclusters
1072 // - The tracklet array (AliTRDseedV1)
1073 // - The seeding configuration
1078 AliRieman *fitter = AliTRDtrackerV1::GetRiemanFitter();
1080 for(Int_t i = 0; i < 4; i++){
1081 fitter->AddPoint(seedcl[i]->GetX(), seedcl[i]->GetY(), seedcl[i]->GetZ(), 1., 10.);
1086 // Update the seed and calculated the chi2 value
1087 chi2[0] = 0; chi2[1] = 0;
1088 for(Int_t ipl = 0; ipl < kNSeedPlanes; ipl++){
1090 chi2[0] += (seedcl[ipl]->GetZ() - fitter->GetZat(seedcl[ipl]->GetX())) * (seedcl[ipl]->GetZ() - fitter->GetZat(seedcl[ipl]->GetX()));
1091 chi2[1] += (seedcl[ipl]->GetY() - fitter->GetYat(seedcl[ipl]->GetX())) * (seedcl[ipl]->GetY() - fitter->GetYat(seedcl[ipl]->GetX()));
1096 //_________________________________________________________________________
1097 Float_t AliTRDtrackerV1::FitTiltedRiemanConstraint(AliTRDseedV1 *tracklets, Double_t zVertex)
1100 // Fits a helix to the clusters. Pad tilting is considered. As constraint it is
1101 // assumed that the vertex position is set to 0.
1102 // This method is very usefull for high-pt particles
1103 // Basis for the fit: (x - x0)^2 + (y - y0)^2 - R^2 = 0
1104 // x0, y0: Center of the circle
1105 // Measured y-position: ymeas = y - tan(phiT)(zc - zt)
1106 // zc: center of the pad row
1107 // Equation which has to be fitted (after transformation):
1108 // a + b * u + e * v + 2*(ymeas + tan(phiT)(z - zVertex))*t = 0
1110 // t = 1/(x^2 + y^2)
1112 // v = 2 * x * tan(phiT) * t
1113 // Parameters in the equation:
1114 // a = -1/y0, b = x0/y0, e = dz/dx
1116 // The Curvature is calculated by the following equation:
1117 // - curv = a/Sqrt(b^2 + 1) = 1/R
1118 // Parameters: - the 6 tracklets
1119 // - the Vertex constraint
1120 // Output: - the Chi2 value of the track
1125 TLinearFitter *fitter = GetTiltedRiemanFitterConstraint();
1126 fitter->StoreData(kTRUE);
1127 fitter->ClearPoints();
1128 AliTRDcluster *cl = NULL;
1130 Float_t x, y, z, w, t, error, tilt;
1133 for(Int_t ilr = 0; ilr < AliTRDgeometry::kNlayer; ilr++){
1134 if(!tracklets[ilr].IsOK()) continue;
1135 for(Int_t itb = 0; itb < AliTRDseedV1::kNclusters; itb++){
1136 if(!tracklets[ilr].IsUsable(itb)) continue;
1137 if(!(cl = tracklets[ilr].GetClusters(itb))) continue;
1138 if(!cl->IsInChamber()) continue;
1142 tilt = tracklets[ilr].GetTilt();
1144 t = 1./(x * x + y * y);
1145 uvt[0] = 2. * x * t;
1146 uvt[1] = 2. * x * t * tilt ;
1147 w = 2. * (y + tilt * (z - zVertex)) * t;
1148 error = 2. * TMath::Sqrt(cl->GetSigmaY2()+tilt*tilt*cl->GetSigmaZ2()) * t;
1149 fitter->AddPoint(uvt, w, error);
1155 // Calculate curvature
1156 Double_t a = fitter->GetParameter(0);
1157 Double_t b = fitter->GetParameter(1);
1158 Double_t curvature = a/TMath::Sqrt(b*b + 1);
1160 Float_t chi2track = fitter->GetChisquare()/Double_t(nPoints);
1161 for(Int_t ip = 0; ip < AliTRDtrackerV1::kNPlanes; ip++)
1162 tracklets[ip].SetC(curvature, 1);
1164 if(AliLog::GetDebugLevel("TRD", "AliTRDtrackerV1")>3) printf("D-AliTRDtrackerV1::FitTiltedRiemanConstraint: Chi2[%f] C[%5.2e] pt[%8.3f]\n", chi2track, curvature, GetBz()*kB2C/curvature);
1166 /* if(fkReconstructor->GetRecoParam()->GetStreamLevel(AliTRDrecoParam::kTracker()) >= 5){
1167 //Linear Model on z-direction
1168 Double_t xref = CalculateReferenceX(tracklets); // Relative to the middle of the stack
1169 Double_t slope = fitter->GetParameter(2);
1170 Double_t zref = slope * xref;
1171 Float_t chi2Z = CalculateChi2Z(tracklets, zref, slope, xref);
1172 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
1173 Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
1174 TTreeSRedirector &treeStreamer = *fkReconstructor->GetDebugStream(AliTRDReconstructor::kTracker);
1175 treeStreamer << "FitTiltedRiemanConstraint"
1176 << "EventNumber=" << eventNumber
1177 << "CandidateNumber=" << candidateNumber
1178 << "Curvature=" << curvature
1179 << "Chi2Track=" << chi2track
1180 << "Chi2Z=" << chi2Z
1187 //_________________________________________________________________________
1188 Float_t AliTRDtrackerV1::FitTiltedRieman(AliTRDseedV1 *tracklets, Bool_t sigError)
1191 // Performs a Riemann fit taking tilting pad correction into account
1192 // The equation of a Riemann circle, where the y position is substituted by the
1193 // measured y-position taking pad tilting into account, has to be transformed
1194 // into a 4-dimensional hyperplane equation
1195 // Riemann circle: (x-x0)^2 + (y-y0)^2 -R^2 = 0
1196 // Measured y-Position: ymeas = y - tan(phiT)(zc - zt)
1197 // zc: center of the pad row
1198 // zt: z-position of the track
1199 // The z-position of the track is assumed to be linear dependent on the x-position
1200 // Transformed equation: a + b * u + c * t + d * v + e * w - 2 * (ymeas + tan(phiT) * zc) * t = 0
1201 // Transformation: u = 2 * x * t
1202 // v = 2 * tan(phiT) * t
1203 // w = 2 * tan(phiT) * (x - xref) * t
1204 // t = 1 / (x^2 + ymeas^2)
1205 // Parameters: a = -1/y0
1207 // c = (R^2 -x0^2 - y0^2)/y0
1210 // If the offset respectively the slope in z-position is impossible, the parameters are fixed using
1211 // results from the simple riemann fit. Afterwards the fit is redone.
1212 // The curvature is calculated according to the formula:
1213 // curv = a/(1 + b^2 + c*a) = 1/R
1215 // Paramters: - Array of tracklets (connected to the track candidate)
1216 // - Flag selecting the error definition
1217 // Output: - Chi2 values of the track (in Parameter list)
1219 TLinearFitter *fitter = GetTiltedRiemanFitter();
1220 fitter->StoreData(kTRUE);
1221 fitter->ClearPoints();
1222 AliTRDLeastSquare zfitter;
1223 AliTRDcluster *cl = NULL;
1225 Double_t xref = CalculateReferenceX(tracklets);
1226 Double_t x, y, z, t, tilt, dx, w, we, erry, errz;
1227 Double_t uvt[4], sumPolY[5], sumPolZ[3];
1228 memset(sumPolY, 0, sizeof(Double_t) * 5);
1229 memset(sumPolZ, 0, sizeof(Double_t) * 3);
1231 // Containers for Least-square fitter
1232 for(Int_t ipl = 0; ipl < kNPlanes; ipl++){
1233 if(!tracklets[ipl].IsOK()) continue;
1234 tilt = tracklets[ipl].GetTilt();
1235 for(Int_t itb = 0; itb < AliTRDseedV1::kNclusters; itb++){
1236 if(!(cl = tracklets[ipl].GetClusters(itb))) continue;
1237 if(!cl->IsInChamber()) continue;
1238 if (!tracklets[ipl].IsUsable(itb)) continue;
1245 uvt[0] = 2. * x * t;
1247 uvt[2] = 2. * tilt * t;
1248 uvt[3] = 2. * tilt * dx * t;
1249 w = 2. * (y + tilt*z) * t;
1250 // error definition changes for the different calls
1252 we *= sigError ? TMath::Sqrt(cl->GetSigmaY2()+tilt*tilt*cl->GetSigmaZ2()) : 0.2;
1253 fitter->AddPoint(uvt, w, we);
1254 zfitter.AddPoint(&x, z, static_cast<Double_t>(TMath::Sqrt(cl->GetSigmaZ2())));
1255 // adding points for covariance matrix estimation
1256 erry = 1./(TMath::Sqrt(cl->GetSigmaY2()) + 0.1); // 0.1 is a systematic error (due to misalignment and miscalibration)
1258 errz = 1./cl->GetSigmaZ2();
1259 for(Int_t ipol = 0; ipol < 5; ipol++){
1260 sumPolY[ipol] += erry;
1263 sumPolZ[ipol] += errz;
1270 if (fitter->Eval()) return 1.e10;
1273 Double_t offset = fitter->GetParameter(3);
1274 Double_t slope = fitter->GetParameter(4);
1276 // Linear fitter - not possible to make boundaries
1277 // Do not accept non possible z and dzdx combinations
1278 Bool_t acceptablez = kTRUE;
1279 Double_t zref = 0.0;
1280 for (Int_t iLayer = 0; iLayer < kNPlanes; iLayer++) {
1281 if(!tracklets[iLayer].IsOK()) continue;
1282 zref = offset + slope * (tracklets[iLayer].GetX0() - xref);
1283 if (TMath::Abs(tracklets[iLayer].GetZfit(0) - zref) > tracklets[iLayer].GetPadLength() * 0.5 + 1.0)
1284 acceptablez = kFALSE;
1287 Double_t dzmf = zfitter.GetFunctionParameter(1);
1288 Double_t zmf = zfitter.GetFunctionValue(&xref);
1289 fgTiltedRieman->FixParameter(3, zmf);
1290 fgTiltedRieman->FixParameter(4, dzmf);
1292 fitter->ReleaseParameter(3);
1293 fitter->ReleaseParameter(4);
1294 offset = fitter->GetParameter(3);
1295 slope = fitter->GetParameter(4);
1298 // Calculate Curvarture
1299 Double_t a = fitter->GetParameter(0);
1300 Double_t b = fitter->GetParameter(1);
1301 Double_t c = fitter->GetParameter(2);
1302 Double_t curvature = 1.0 + b*b - c*a;
1303 if (curvature > 0.0) curvature = a / TMath::Sqrt(curvature);
1305 Double_t chi2track = fitter->GetChisquare()/Double_t(nPoints);
1307 // Prepare error calculation
1308 TMatrixD covarPolY(3,3);
1309 covarPolY(0,0) = sumPolY[0]; covarPolY(1,1) = sumPolY[2]; covarPolY(2,2) = sumPolY[4];
1310 covarPolY(0,1) = covarPolY(1,0) = sumPolY[1];
1311 covarPolY(0,2) = covarPolY(2,0) = sumPolY[2];
1312 covarPolY(2,1) = covarPolY(1,2) = sumPolY[3];
1314 TMatrixD covarPolZ(2,2);
1315 covarPolZ(0,0) = sumPolZ[0]; covarPolZ(1,1) = sumPolZ[2];
1316 covarPolZ(1,0) = covarPolZ(0,1) = sumPolZ[1];
1319 // Update the tracklets
1320 Double_t x1, dy, dz;
1322 memset(cov, 0, sizeof(Double_t) * 15);
1323 for(Int_t iLayer = 0; iLayer < AliTRDtrackerV1::kNPlanes; iLayer++) {
1325 x = tracklets[iLayer].GetX0();
1331 memset(cov, 0, sizeof(Double_t) * 3);
1332 TMatrixD transform(3,3);
1335 transform(0,2) = x*x;
1339 TMatrixD covariance(transform, TMatrixD::kMult, covarPolY);
1340 covariance *= transform.T();
1341 TMatrixD transformZ(2,2);
1342 transformZ(0,0) = transformZ(1,1) = 1;
1343 transformZ(0,1) = x;
1344 TMatrixD covarZ(transformZ, TMatrixD::kMult, covarPolZ);
1345 covarZ *= transformZ.T();
1346 // y: R^2 = (x - x0)^2 + (y - y0)^2
1347 // => y = y0 +/- Sqrt(R^2 - (x - x0)^2)
1348 // R = Sqrt() = 1/Curvature
1349 // => y = y0 +/- Sqrt(1/Curvature^2 - (x - x0)^2)
1350 Double_t res = (x * a + b); // = (x - x0)/y0
1352 res = 1.0 - c * a + b * b - res; // = (R^2 - (x - x0)^2)/y0^2
1354 res = TMath::Sqrt(res);
1355 y = (1.0 - res) / a;
1357 cov[0] = covariance(0,0);
1358 cov[2] = covarZ(0,0);
1361 // dy: R^2 = (x - x0)^2 + (y - y0)^2
1362 // => y = +/- Sqrt(R^2 - (x - x0)^2) + y0
1363 // => dy/dx = (x - x0)/Sqrt(R^2 - (x - x0)^2)
1364 // Curvature: cr = 1/R = a/Sqrt(1 + b^2 - c*a)
1365 // => dy/dx = (x - x0)/(1/(cr^2) - (x - x0)^2)
1366 Double_t x0 = -b / a;
1367 if (-c * a + b * b + 1 > 0) {
1368 if (1.0/(curvature * curvature) - (x - x0) * (x - x0) > 0.0) {
1369 Double_t yderiv = (x - x0) / TMath::Sqrt(1.0/(curvature * curvature) - (x - x0) * (x - x0));
1370 if (a < 0) yderiv *= -1.0;
1374 z = offset + slope * (x - xref);
1376 tracklets[iLayer].SetYref(0, y);
1377 tracklets[iLayer].SetYref(1, dy);
1378 tracklets[iLayer].SetZref(0, z);
1379 tracklets[iLayer].SetZref(1, dz);
1380 tracklets[iLayer].SetC(curvature);
1381 tracklets[iLayer].SetCovRef(cov);
1382 tracklets[iLayer].SetChi2(chi2track);
1384 if(AliLog::GetDebugLevel("TRD", "AliTRDtrackerV1")>3) printf("D-AliTRDtrackerV1::FitTiltedRieman: Chi2[%f] C[%5.2e] pt[%8.3f]\n", chi2track, curvature, GetBz()*kB2C/curvature);
1386 /* if(fkReconstructor->GetRecoParam()->GetStreamLevel(AliTRDrecoParam::kTracker) >=5){
1387 TTreeSRedirector &cstreamer = *fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker);
1388 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
1389 Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
1390 Double_t chi2z = CalculateChi2Z(tracklets, offset, slope, xref);
1391 cstreamer << "FitTiltedRieman0"
1392 << "EventNumber=" << eventNumber
1393 << "CandidateNumber=" << candidateNumber
1395 << "Chi2Z=" << chi2z
1402 //____________________________________________________________________
1403 Double_t AliTRDtrackerV1::FitLine(const AliTRDtrackV1 *track, AliTRDseedV1 *tracklets, Bool_t err, Int_t np, AliTrackPoint *points)
1406 // Fit track with a staight line
1407 // Fills an AliTrackPoint array with np points
1408 // Function should be used to refit tracks when no magnetic field was on
1410 AliTRDLeastSquare yfitter, zfitter;
1411 AliTRDcluster *cl = NULL;
1413 AliTRDseedV1 work[kNPlanes], *tracklet = NULL;
1415 for(Int_t ipl = 0; ipl < kNPlanes; ipl++){
1416 if(!(tracklet = track->GetTracklet(ipl))) continue;
1417 if(!tracklet->IsOK()) continue;
1418 new(&work[ipl]) AliTRDseedV1(*tracklet);
1420 tracklets = &work[0];
1423 Double_t xref = CalculateReferenceX(tracklets);
1424 Double_t x, y, z, dx, ye, yr, tilt;
1425 for(Int_t ipl = 0; ipl < kNPlanes; ipl++){
1426 if(!tracklets[ipl].IsOK()) continue;
1427 for(Int_t itb = 0; itb < fgNTimeBins; itb++){
1428 if(!(cl = tracklets[ipl].GetClusters(itb))) continue;
1429 if (!tracklets[ipl].IsUsable(itb)) continue;
1433 zfitter.AddPoint(&dx, z, static_cast<Double_t>(TMath::Sqrt(cl->GetSigmaZ2())));
1437 Double_t z0 = zfitter.GetFunctionParameter(0);
1438 Double_t dzdx = zfitter.GetFunctionParameter(1);
1439 for(Int_t ipl = 0; ipl < kNPlanes; ipl++){
1440 if(!tracklets[ipl].IsOK()) continue;
1441 for(Int_t itb = 0; itb < fgNTimeBins; itb++){
1442 if(!(cl = tracklets[ipl].GetClusters(itb))) continue;
1443 if (!tracklets[ipl].IsUsable(itb)) continue;
1447 tilt = tracklets[ipl].GetTilt();
1449 yr = y + tilt*(z - z0 - dzdx*dx);
1450 // error definition changes for the different calls
1451 ye = tilt*TMath::Sqrt(cl->GetSigmaZ2());
1452 ye += err ? tracklets[ipl].GetSigmaY() : 0.2;
1453 yfitter.AddPoint(&dx, yr, ye);
1457 Double_t y0 = yfitter.GetFunctionParameter(0);
1458 Double_t dydx = yfitter.GetFunctionParameter(1);
1459 Double_t chi2 = 0.;//yfitter.GetChisquare()/Double_t(nPoints);
1461 //update track points array
1464 for(int ip=0; ip<np; ip++){
1465 points[ip].GetXYZ(xyz);
1466 xyz[1] = y0 + dydx * (xyz[0] - xref);
1467 xyz[2] = z0 + dzdx * (xyz[0] - xref);
1468 points[ip].SetXYZ(xyz);
1475 //_________________________________________________________________________
1476 Double_t AliTRDtrackerV1::FitRiemanTilt(const AliTRDtrackV1 *track, AliTRDseedV1 *tracklets, Bool_t sigError, Int_t np, AliTrackPoint *points)
1479 // Performs a Riemann fit taking tilting pad correction into account
1481 // Paramters: - Array of tracklets (connected to the track candidate)
1482 // - Flag selecting the error definition
1483 // Output: - Chi2 values of the track (in Parameter list)
1485 // The equations which has to be solved simultaneously are:
1487 // R^{2} = (x-x_{0})^{2} + (y^{*}-y_{0})^{2}
1488 // y^{*} = y - tg(h)(z - z_{t})
1489 // z_{t} = z_{0}+dzdx*(x-x_{r})
1491 // with (x, y, z) the coordinate of the cluster, (x_0, y_0, z_0) the coordinate of the center of the Riemann circle,
1492 // R its radius, x_r a constant refrence radial position in the middle of the TRD stack and dzdx the slope of the
1493 // track in the x-z plane. Using the following transformations
1495 // t = 1 / (x^{2} + y^{2})
1497 // v = 2 * tan(h) * t
1498 // w = 2 * tan(h) * (x - x_{r}) * t
1500 // One gets the following linear equation
1502 // a + b * u + c * t + d * v + e * w = 2 * (y + tg(h) * z) * t
1504 // where the coefficients have the following meaning
1508 // c = (R^{2} -x_{0}^{2} - y_{0}^{2})/y_{0}
1512 // The error calculation for the free term is thus
1514 // #sigma = 2 * #sqrt{#sigma^{2}_{y} + (tilt corr ...) + tg^{2}(h) * #sigma^{2}_{z}} * t
1517 // From this simple model one can compute chi^2 estimates and a rough approximation of pt from the curvature according
1520 // C = 1/R = a/(1 + b^{2} + c*a)
1524 // M.Ivanov <M.Ivanov@gsi.de>
1525 // A.Bercuci <A.Bercuci@gsi.de>
1526 // M.Fasel <M.Fasel@gsi.de>
1528 TLinearFitter *fitter = GetTiltedRiemanFitter();
1529 fitter->StoreData(kTRUE);
1530 fitter->ClearPoints();
1531 AliTRDLeastSquare zfitter;
1532 AliTRDcluster *cl = NULL;
1534 AliTRDseedV1 work[kNPlanes], *tracklet = NULL;
1536 for(Int_t ipl = 0; ipl < kNPlanes; ipl++){
1537 if(!(tracklet = track->GetTracklet(ipl))) continue;
1538 if(!tracklet->IsOK()) continue;
1539 new(&work[ipl]) AliTRDseedV1(*tracklet);
1541 tracklets = &work[0];
1544 Double_t xref = CalculateReferenceX(tracklets);
1545 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);
1546 Double_t x, y, z, t, tilt, dx, w, we;
1549 // Containers for Least-square fitter
1550 for(Int_t ipl = 0; ipl < kNPlanes; ipl++){
1551 if(!tracklets[ipl].IsOK()) continue;
1552 for(Int_t itb = 0; itb < AliTRDseedV1::kNclusters; itb++){
1553 if(!(cl = tracklets[ipl].GetClusters(itb))) continue;
1554 //if (!tracklets[ipl].IsUsable(itb)) continue;
1558 tilt = tracklets[ipl].GetTilt();
1562 uvt[0] = 2. * x * t;
1564 uvt[2] = 2. * tilt * t;
1565 uvt[3] = 2. * tilt * dx * t;
1566 w = 2. * (y + tilt*z) * t;
1567 // error definition changes for the different calls
1569 we *= sigError ? TMath::Sqrt(cl->GetSigmaY2()) : 0.2;
1570 fitter->AddPoint(uvt, w, we);
1571 zfitter.AddPoint(&x, z, static_cast<Double_t>(TMath::Sqrt(cl->GetSigmaZ2())));
1575 if(fitter->Eval()) return 1.E10;
1577 Double_t z0 = fitter->GetParameter(3);
1578 Double_t dzdx = fitter->GetParameter(4);
1581 // Linear fitter - not possible to make boundaries
1582 // Do not accept non possible z and dzdx combinations
1583 Bool_t accept = kTRUE;
1584 Double_t zref = 0.0;
1585 for (Int_t iLayer = 0; iLayer < kNPlanes; iLayer++) {
1586 if(!tracklets[iLayer].IsOK()) continue;
1587 zref = z0 + dzdx * (tracklets[iLayer].GetX0() - xref);
1588 if (TMath::Abs(tracklets[iLayer].GetZfit(0) - zref) > tracklets[iLayer].GetPadLength() * 0.5 + 1.0)
1593 Double_t dzmf = zfitter.GetFunctionParameter(1);
1594 Double_t zmf = zfitter.GetFunctionValue(&xref);
1595 fitter->FixParameter(3, zmf);
1596 fitter->FixParameter(4, dzmf);
1598 fitter->ReleaseParameter(3);
1599 fitter->ReleaseParameter(4);
1600 z0 = fitter->GetParameter(3); // = zmf ?
1601 dzdx = fitter->GetParameter(4); // = dzmf ?
1604 // Calculate Curvature
1605 Double_t a = fitter->GetParameter(0);
1606 Double_t b = fitter->GetParameter(1);
1607 Double_t c = fitter->GetParameter(2);
1608 Double_t y0 = 1. / a;
1609 Double_t x0 = -b * y0;
1610 Double_t tmp = y0*y0 + x0*x0 - c*y0;
1611 if(tmp<=0.) return 1.E10;
1612 Double_t radius = TMath::Sqrt(tmp);
1613 Double_t curvature = 1.0 + b*b - c*a;
1614 if (curvature > 0.0) curvature = a / TMath::Sqrt(curvature);
1616 // Calculate chi2 of the fit
1617 Double_t chi2 = fitter->GetChisquare()/Double_t(nPoints);
1618 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);
1620 // Update the tracklets
1622 for(Int_t ip = 0; ip < kNPlanes; ip++) {
1623 x = tracklets[ip].GetX0();
1624 tmp = radius*radius-(x-x0)*(x-x0);
1625 if(tmp <= 0.) continue;
1626 tmp = TMath::Sqrt(tmp);
1628 // y: R^2 = (x - x0)^2 + (y - y0)^2
1629 // => y = y0 +/- Sqrt(R^2 - (x - x0)^2)
1630 tracklets[ip].SetYref(0, y0 - (y0>0.?1.:-1)*tmp);
1631 // => dy/dx = (x - x0)/Sqrt(R^2 - (x - x0)^2)
1632 tracklets[ip].SetYref(1, (x - x0) / tmp);
1633 tracklets[ip].SetZref(0, z0 + dzdx * (x - xref));
1634 tracklets[ip].SetZref(1, dzdx);
1635 tracklets[ip].SetC(curvature);
1636 tracklets[ip].SetChi2(chi2);
1639 //update track points array
1642 for(int ip=0; ip<np; ip++){
1643 points[ip].GetXYZ(xyz);
1644 xyz[1] = TMath::Abs(xyz[0] - x0) > radius ? 100. : y0 - (y0>0.?1.:-1.)*TMath::Sqrt((radius-(xyz[0]-x0))*(radius+(xyz[0]-x0)));
1645 xyz[2] = z0 + dzdx * (xyz[0] - xref);
1646 points[ip].SetXYZ(xyz);
1654 //____________________________________________________________________
1655 Double_t AliTRDtrackerV1::FitKalman(AliTRDtrackV1 *track, AliTRDseedV1 * const tracklets, Bool_t up, Int_t np, AliTrackPoint *points)
1657 // Kalman filter implementation for the TRD.
1658 // It returns the positions of the fit in the array "points"
1660 // Author : A.Bercuci@gsi.de
1662 // printf("Start track @ x[%f]\n", track->GetX());
1664 //prepare marker points along the track
1665 Int_t ip = np ? 0 : 1;
1667 if((up?-1:1) * (track->GetX() - points[ip].GetX()) > 0.) break;
1668 //printf("AliTRDtrackerV1::FitKalman() : Skip track marker x[%d] = %7.3f. Before track start ( %7.3f ).\n", ip, points[ip].GetX(), track->GetX());
1671 //if(points) printf("First marker point @ x[%d] = %f\n", ip, points[ip].GetX());
1674 AliTRDseedV1 tracklet;
1675 AliTRDseedV1 *ptrTracklet = NULL;
1677 //Loop through the TRD planes
1678 for (Int_t jplane = 0; jplane < kNPlanes; jplane++) {
1679 // GET TRACKLET OR BUILT IT
1680 Int_t iplane = up ? jplane : kNPlanes - 1 - jplane;
1682 if(!(ptrTracklet = &tracklets[iplane])) continue;
1684 if(!(ptrTracklet = track->GetTracklet(iplane))){
1685 /*AliTRDtrackerV1 *tracker = NULL;
1686 if(!(tracker = dynamic_cast<AliTRDtrackerV1*>( AliTRDrecoParam:Tracker()))) continue;
1687 ptrTracklet = new(&tracklet) AliTRDseedV1(iplane);
1688 if(!tracker->MakeTracklet(ptrTracklet, track)) */
1692 if(!ptrTracklet->IsOK()) continue;
1694 Double_t x = ptrTracklet->GetX0();
1697 //don't do anything if next marker is after next update point.
1698 if((up?-1:1) * (points[ip].GetX() - x) - fgkMaxStep < 0) break;
1699 if(((up?-1:1) * (points[ip].GetX() - track->GetX()) < 0) && !PropagateToX(*track, points[ip].GetX(), fgkMaxStep)) return -1.;
1701 Double_t xyz[3]; // should also get the covariance
1703 track->Global2LocalPosition(xyz, track->GetAlpha());
1704 points[ip].SetXYZ(xyz[0], xyz[1], xyz[2]);
1707 // printf("plane[%d] tracklet[%p] x[%f]\n", iplane, ptrTracklet, x);
1709 // Propagate closer to the next update point
1710 if(((up?-1:1) * (x - track->GetX()) + fgkMaxStep < 0) && !PropagateToX(*track, x + (up?-1:1)*fgkMaxStep, fgkMaxStep)) return -1.;
1712 if(!AdjustSector(track)) return -1;
1713 if(TMath::Abs(track->GetSnp()) > fgkMaxSnp) return -1;
1715 //load tracklet to the tracker and the track
1717 if((index = FindTracklet(ptrTracklet)) < 0){
1718 ptrTracklet = SetTracklet(&tracklet);
1719 index = fTracklets->GetEntriesFast()-1;
1721 track->SetTracklet(ptrTracklet, index);*/
1724 // register tracklet to track with tracklet creation !!
1725 // PropagateBack : loaded tracklet to the tracker and update index
1726 // RefitInward : update index
1727 // MakeTrack : loaded tracklet to the tracker and update index
1728 if(!tracklets) track->SetTracklet(ptrTracklet, -1);
1731 //Calculate the mean material budget along the path inside the chamber
1732 Double_t xyz0[3]; track->GetXYZ(xyz0);
1733 Double_t alpha = track->GetAlpha();
1734 Double_t xyz1[3], y, z;
1735 if(!track->GetProlongation(x, y, z)) return -1;
1736 xyz1[0] = x * TMath::Cos(alpha) - y * TMath::Sin(alpha);
1737 xyz1[1] = +x * TMath::Sin(alpha) + y * TMath::Cos(alpha);
1739 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
1741 if(AliTracker::MeanMaterialBudget(xyz0, xyz1, param) <=0.) break;
1742 Double_t xrho = param[0]*param[4]; // density*length
1743 Double_t xx0 = param[1]; // radiation length
1745 //Propagate the track
1746 track->PropagateTo(x, xx0, xrho);
1747 if (!AdjustSector(track)) break;
1750 Double_t cov[3]; ptrTracklet->GetCovAt(x, cov);
1751 Double_t p[2] = { ptrTracklet->GetY(), ptrTracklet->GetZ()};
1752 Double_t chi2 = ((AliExternalTrackParam*)track)->GetPredictedChi2(p, cov);
1753 if(chi2<1e+10) ((AliExternalTrackParam*)track)->Update(p, cov);
1756 //Reset material budget if 2 consecutive gold
1757 if(iplane>0 && track->GetTracklet(iplane-1) && ptrTracklet->GetN() + track->GetTracklet(iplane-1)->GetN() > 20) track->SetBudget(2, 0.);
1758 } // end planes loop
1762 if(((up?-1:1) * (points[ip].GetX() - track->GetX()) < 0) && !PropagateToX(*track, points[ip].GetX(), fgkMaxStep)) return -1.;
1764 Double_t xyz[3]; // should also get the covariance
1766 track->Global2LocalPosition(xyz, track->GetAlpha());
1767 points[ip].SetXYZ(xyz[0], xyz[1], xyz[2]);
1771 return track->GetChi2();
1774 //_________________________________________________________________________
1775 Float_t AliTRDtrackerV1::CalculateChi2Z(const AliTRDseedV1 *tracklets, Double_t offset, Double_t slope, Double_t xref)
1778 // Calculates the chi2-value of the track in z-Direction including tilting pad correction.
1779 // A linear dependence on the x-value serves as a model.
1780 // The parameters are related to the tilted Riemann fit.
1781 // Parameters: - Array of tracklets (AliTRDseedV1) related to the track candidate
1782 // - the offset for the reference x
1784 // - the reference x position
1785 // Output: - The Chi2 value of the track in z-Direction
1787 Float_t chi2Z = 0, nLayers = 0;
1788 for (Int_t iLayer = 0; iLayer < AliTRDgeometry::kNlayer; iLayer++) {
1789 if(!tracklets[iLayer].IsOK()) continue;
1790 Double_t z = offset + slope * (tracklets[iLayer].GetX0() - xref);
1791 chi2Z += TMath::Abs(tracklets[iLayer].GetZfit(0) - z);
1794 chi2Z /= TMath::Max((nLayers - 3.0),1.0);
1798 //_____________________________________________________________________________
1799 Int_t AliTRDtrackerV1::PropagateToX(AliTRDtrackV1 &t, Double_t xToGo, Double_t maxStep)
1802 // Starting from current X-position of track <t> this function
1803 // extrapolates the track up to radial position <xToGo>.
1804 // Returns 1 if track reaches the plane, and 0 otherwise
1807 const Double_t kEpsilon = 0.00001;
1809 // Current track X-position
1810 Double_t xpos = t.GetX();
1812 // Direction: inward or outward
1813 Double_t dir = (xpos < xToGo) ? 1.0 : -1.0;
1815 while (((xToGo - xpos) * dir) > kEpsilon) {
1824 // The next step size
1825 Double_t step = dir * TMath::Min(TMath::Abs(xToGo-xpos),maxStep);
1827 // Get the global position of the starting point
1830 // X-position after next step
1833 // Get local Y and Z at the X-position of the next step
1834 if(t.GetProlongation(x,y,z)<0) return 0; // No prolongation possible
1836 // The global position of the end point of this prolongation step
1837 xyz1[0] = x * TMath::Cos(t.GetAlpha()) - y * TMath::Sin(t.GetAlpha());
1838 xyz1[1] = +x * TMath::Sin(t.GetAlpha()) + y * TMath::Cos(t.GetAlpha());
1841 // Calculate the mean material budget between start and
1842 // end point of this prolongation step
1843 if(AliTracker::MeanMaterialBudget(xyz0, xyz1, param)<=0.) return 0;
1845 // Propagate the track to the X-position after the next step
1846 if (!t.PropagateTo(x, param[1], param[0]*param[4])) return 0;
1848 // Rotate the track if necessary
1849 if(!AdjustSector(&t)) return 0;
1851 // New track X-position
1861 //_____________________________________________________________________________
1862 Bool_t AliTRDtrackerV1::ReadClusters(TTree *clusterTree)
1865 // Reads AliTRDclusters from the file.
1866 // The names of the cluster tree and branches
1867 // should match the ones used in AliTRDclusterizer::WriteClusters()
1870 Int_t nsize = Int_t(clusterTree->GetTotBytes() / (sizeof(AliTRDcluster)));
1871 TObjArray *clusterArray = new TObjArray(nsize+1000);
1873 TBranch *branch = clusterTree->GetBranch("TRDcluster");
1875 AliError("Can't get the branch !");
1878 branch->SetAddress(&clusterArray);
1881 Float_t nclusters = fkRecoParam->GetNClusters();
1882 if(fkReconstructor->IsHLT()) nclusters /= AliTRDgeometry::kNsector;
1883 fClusters = new TClonesArray("AliTRDcluster", Int_t(nclusters));
1884 fClusters->SetOwner(kTRUE);
1887 // Loop through all entries in the tree
1888 Int_t nEntries = (Int_t) clusterTree->GetEntries();
1891 AliTRDcluster *c = NULL;
1892 for (Int_t iEntry = 0; iEntry < nEntries; iEntry++) {
1894 nbytes += clusterTree->GetEvent(iEntry);
1896 // Get the number of points in the detector
1897 Int_t nCluster = clusterArray->GetEntriesFast();
1898 for (Int_t iCluster = 0; iCluster < nCluster; iCluster++) {
1899 if(!(c = (AliTRDcluster *) clusterArray->UncheckedAt(iCluster))) continue;
1900 new((*fClusters)[ncl++]) AliTRDcluster(*c);
1901 delete (clusterArray->RemoveAt(iCluster));
1904 delete clusterArray;
1909 //_____________________________________________________________________________
1910 Int_t AliTRDtrackerV1::LoadClusters(TTree *cTree)
1913 // Fills clusters into TRD tracking sectors
1916 fkRecoParam = fkReconstructor->GetRecoParam(); // load reco param for this event
1918 if(!fkReconstructor->IsWritingClusters()){
1919 fClusters = AliTRDReconstructor::GetClusters();
1921 if(!ReadClusters(cTree)) {
1922 AliError("Problem with reading the clusters !");
1928 if(!fClusters || !fClusters->GetEntriesFast()){
1929 AliInfo("No TRD clusters");
1934 BuildTrackingContainers();
1936 //Int_t ncl = fClusters->GetEntriesFast();
1937 //AliInfo(Form("Clusters %d [%6.2f %% in the active volume]", ncl, 100.*float(nin)/ncl));
1942 //_____________________________________________________________________________
1943 Int_t AliTRDtrackerV1::LoadClusters(TClonesArray * const clusters)
1946 // Fills clusters into TRD tracking sectors
1947 // Function for use in the HLT
1949 if(!clusters || !clusters->GetEntriesFast()){
1950 AliInfo("No TRD clusters");
1954 fClusters = clusters;
1957 fkRecoParam = fkReconstructor->GetRecoParam(); // load reco param for this event
1958 BuildTrackingContainers();
1960 //Int_t ncl = fClusters->GetEntriesFast();
1961 //AliInfo(Form("Clusters %d [%6.2f %% in the active volume]", ncl, 100.*float(nin)/ncl));
1967 //____________________________________________________________________
1968 Int_t AliTRDtrackerV1::BuildTrackingContainers()
1970 // Building tracking containers for clusters
1972 Int_t nin(0), ncl(fClusters->GetEntriesFast());
1974 AliTRDcluster *c = (AliTRDcluster *) fClusters->UncheckedAt(ncl);
1975 if(c->IsInChamber()) nin++;
1976 if(fkReconstructor->IsHLT()) c->SetRPhiMethod(AliTRDcluster::kCOG);
1977 Int_t detector = c->GetDetector();
1978 Int_t sector = fGeom->GetSector(detector);
1979 Int_t stack = fGeom->GetStack(detector);
1980 Int_t layer = fGeom->GetLayer(detector);
1982 fTrSec[sector].GetChamber(stack, layer, kTRUE)->InsertCluster(c, ncl);
1985 for(int isector =0; isector<AliTRDgeometry::kNsector; isector++){
1986 if(!fTrSec[isector].GetNChambers()) continue;
1987 fTrSec[isector].Init(fkReconstructor);
1995 //____________________________________________________________________
1996 void AliTRDtrackerV1::UnloadClusters()
1999 // Clears the arrays of clusters and tracks. Resets sectors and timebins
2000 // If option "force" is also set the containers are also deleted. This is useful
2005 if(HasRemoveContainers()){delete fTracks; fTracks = NULL;}
2008 fTracklets->Delete();
2009 if(HasRemoveContainers()){delete fTracklets; fTracklets = NULL;}
2012 if(IsClustersOwner()) fClusters->Delete();
2014 // save clusters array in the reconstructor for further use.
2015 if(!fkReconstructor->IsWritingClusters()){
2016 AliTRDReconstructor::SetClusters(fClusters);
2017 SetClustersOwner(kFALSE);
2018 } else AliTRDReconstructor::SetClusters(NULL);
2021 for (int i = 0; i < AliTRDgeometry::kNsector; i++) fTrSec[i].Clear();
2023 // Increment the Event Number
2024 AliTRDtrackerDebug::SetEventNumber(AliTRDtrackerDebug::GetEventNumber() + 1);
2027 // //____________________________________________________________________
2028 // void AliTRDtrackerV1::UseClusters(const AliKalmanTrack *t, Int_t) const
2030 // const AliTRDtrackV1 *track = dynamic_cast<const AliTRDtrackV1*>(t);
2031 // if(!track) return;
2033 // AliTRDseedV1 *tracklet = NULL;
2034 // for(Int_t ily=AliTRDgeometry::kNlayer; ily--;){
2035 // if(!(tracklet = track->GetTracklet(ily))) continue;
2036 // AliTRDcluster *c = NULL;
2037 // for(Int_t ic=AliTRDseed::kNclusters; ic--;){
2038 // if(!(c=tracklet->GetClusters(ic))) continue;
2045 //_____________________________________________________________________________
2046 Bool_t AliTRDtrackerV1::AdjustSector(AliTRDtrackV1 *const track)
2049 // Rotates the track when necessary
2052 Double_t alpha = AliTRDgeometry::GetAlpha();
2053 Double_t y = track->GetY();
2054 Double_t ymax = track->GetX()*TMath::Tan(0.5*alpha);
2057 if (!track->Rotate( alpha)) {
2061 else if (y < -ymax) {
2062 if (!track->Rotate(-alpha)) {
2072 //____________________________________________________________________
2073 AliTRDseedV1* AliTRDtrackerV1::GetTracklet(AliTRDtrackV1 *const track, Int_t p, Int_t &idx)
2075 // Find tracklet for TRD track <track>
2084 // Detailed description
2086 idx = track->GetTrackletIndex(p);
2087 AliTRDseedV1 *tracklet = (idx<0) ? NULL : (AliTRDseedV1*)fTracklets->UncheckedAt(idx);
2092 //____________________________________________________________________
2093 AliTRDseedV1* AliTRDtrackerV1::SetTracklet(const AliTRDseedV1 * const tracklet)
2095 // Add this tracklet to the list of tracklets stored in the tracker
2098 // - tracklet : pointer to the tracklet to be added to the list
2101 // - the index of the new tracklet in the tracker tracklets list
2103 // Detailed description
2104 // Build the tracklets list if it is not yet created (late initialization)
2105 // and adds the new tracklet to the list.
2108 fTracklets = new TClonesArray("AliTRDseedV1", AliTRDgeometry::Nsector()*kMaxTracksStack);
2109 fTracklets->SetOwner(kTRUE);
2111 Int_t nentries = fTracklets->GetEntriesFast();
2112 return new ((*fTracklets)[nentries]) AliTRDseedV1(*tracklet);
2115 //____________________________________________________________________
2116 AliTRDtrackV1* AliTRDtrackerV1::SetTrack(const AliTRDtrackV1 * const track)
2118 // Add this track to the list of tracks stored in the tracker
2121 // - track : pointer to the track to be added to the list
2124 // - the pointer added
2126 // Detailed description
2127 // Build the tracks list if it is not yet created (late initialization)
2128 // and adds the new track to the list.
2131 fTracks = new TClonesArray("AliTRDtrackV1", AliTRDgeometry::Nsector()*kMaxTracksStack);
2132 fTracks->SetOwner(kTRUE);
2134 Int_t nentries = fTracks->GetEntriesFast();
2135 return new ((*fTracks)[nentries]) AliTRDtrackV1(*track);
2140 //____________________________________________________________________
2141 Int_t AliTRDtrackerV1::Clusters2TracksSM(Int_t sector, AliESDEvent *esd)
2144 // Steer tracking for one SM.
2147 // sector : Array of (SM) propagation layers containing clusters
2148 // esd : The current ESD event. On output it contains the also
2149 // the ESD (TRD) tracks found in this SM.
2152 // Number of tracks found in this TRD supermodule.
2154 // Detailed description
2156 // 1. Unpack AliTRDpropagationLayers objects for each stack.
2157 // 2. Launch stack tracking.
2158 // See AliTRDtrackerV1::Clusters2TracksStack() for details.
2159 // 3. Pack results in the ESD event.
2163 Int_t nChambers = 0;
2164 AliTRDtrackingChamber **stack = NULL, *chamber = NULL;
2165 for(int istack = 0; istack<AliTRDgeometry::kNstack; istack++){
2166 if(!(stack = fTrSec[sector].GetStack(istack))) continue;
2168 for(int ilayer=0; ilayer<AliTRDgeometry::kNlayer; ilayer++){
2169 if(!(chamber = stack[ilayer])) continue;
2170 if(chamber->GetNClusters() < fgNTimeBins * fkRecoParam->GetFindableClusters()) continue;
2172 //AliInfo(Form("sector %d stack %d layer %d clusters %d", sector, istack, ilayer, chamber->GetNClusters()));
2174 if(nChambers < 4) continue;
2175 //AliInfo(Form("Doing stack %d", istack));
2176 nTracks += Clusters2TracksStack(stack, fTracksESD);
2178 if(nTracks) AliDebug(2, Form("Number of tracks: SM_%02d[%d]", sector, nTracks));
2180 for(int itrack=0; itrack<nTracks; itrack++){
2181 AliESDtrack *esdTrack((AliESDtrack*)(fTracksESD->operator[](itrack)));
2182 Int_t id = esd->AddTrack(esdTrack);
2184 // set ESD id to stand alone TRD tracks
2185 if (fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) > 0){
2186 esdTrack=esd->GetTrack(id);
2187 TObject *o(NULL); Int_t ic(0);
2188 AliTRDtrackV1 *calibTrack(NULL);
2189 while((o = esdTrack->GetCalibObject(ic++))){
2190 if(!(calibTrack = dynamic_cast<AliTRDtrackV1*>(o))) continue;
2191 calibTrack->SetESDid(esdTrack->GetID());
2197 // Reset Track and Candidate Number
2198 AliTRDtrackerDebug::SetCandidateNumber(0);
2199 AliTRDtrackerDebug::SetTrackNumber(0);
2201 // delete ESD tracks in the array
2202 fTracksESD->Delete();
2206 //____________________________________________________________________
2207 Int_t AliTRDtrackerV1::Clusters2TracksStack(AliTRDtrackingChamber **stack, TClonesArray * const esdTrackList)
2210 // Make tracks in one TRD stack.
2213 // layer : Array of stack propagation layers containing clusters
2214 // esdTrackList : Array of ESD tracks found by the stand alone tracker.
2215 // On exit the tracks found in this stack are appended.
2218 // Number of tracks found in this stack.
2220 // Detailed description
2222 // 1. Find the 3 most useful seeding chambers. See BuildSeedingConfigs() for details.
2223 // 2. Steer AliTRDtrackerV1::MakeSeeds() for 3 seeding layer configurations.
2224 // See AliTRDtrackerV1::MakeSeeds() for more details.
2225 // 3. Arrange track candidates in decreasing order of their quality
2226 // 4. Classify tracks in 5 categories according to:
2227 // a) number of layers crossed
2229 // 5. Sign clusters by tracks in decreasing order of track quality
2230 // 6. Build AliTRDtrack out of seeding tracklets
2232 // 8. Build ESD track and register it to the output list
2235 AliTRDtrackingChamber *chamber = NULL;
2236 AliTRDtrackingChamber **ci = NULL;
2237 AliTRDseedV1 sseed[kMaxTracksStack*6]; // to be initialized
2238 Int_t pars[4]; // MakeSeeds parameters
2240 //Double_t alpha = AliTRDgeometry::GetAlpha();
2241 //Double_t shift = .5 * alpha;
2242 Int_t configs[kNConfigs];
2244 // Purge used clusters from the containers
2246 for(Int_t ic = kNPlanes; ic--; ci++){
2247 if(!(*ci)) continue;
2251 // Build initial seeding configurations
2252 Double_t quality = BuildSeedingConfigs(stack, configs);
2253 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) > 10){
2254 AliInfo(Form("Plane config %d %d %d Quality %f"
2255 , configs[0], configs[1], configs[2], quality));
2259 // Initialize contors
2260 Int_t ntracks, // number of TRD track candidates
2261 ntracks1, // number of registered TRD tracks/iter
2262 ntracks2 = 0; // number of all registered TRD tracks in stack
2266 Int_t ic = 0; ci = &stack[0];
2267 while(ic<kNPlanes && !(*ci)){ic++; ci++;}
2268 if(!(*ci)) return ntracks2;
2269 Int_t istack = fGeom->GetStack((*ci)->GetDetector());
2272 // Loop over seeding configurations
2273 ntracks = 0; ntracks1 = 0;
2274 for (Int_t iconf = 0; iconf<fkRecoParam->GetNumberOfSeedConfigs(); iconf++) {
2275 pars[0] = configs[iconf];
2278 ntracks = MakeSeeds(stack, &sseed[6*ntracks], pars);
2279 //AliInfo(Form("Number of Tracks after iteration step %d: %d\n", iconf, ntracks));
2280 if(ntracks == kMaxTracksStack) break;
2282 AliDebug(2, Form("Candidate TRD tracks %d in iteration %d.", ntracks, fSieveSeeding));
2285 // Sort the seeds according to their quality
2286 Int_t sort[kMaxTracksStack+1];
2287 TMath::Sort(ntracks, fTrackQuality, sort, kTRUE);
2288 if(AliLog::GetDebugLevel("TRD", "AliTRDtrackerV1") > 2){
2289 AliDebug(3, "Track candidates classification:");
2290 for (Int_t it(0); it < ntracks; it++) {
2292 printf(" %2d idx[%d] Quality[%e]\n", it, jt, fTrackQuality[jt]);
2296 // Initialize number of tracks so far and logic switches
2297 Int_t ntracks0 = esdTrackList->GetEntriesFast();
2298 Bool_t signedTrack[kMaxTracksStack];
2299 Bool_t fakeTrack[kMaxTracksStack];
2300 for (Int_t i=0; i<ntracks; i++){
2301 signedTrack[i] = kFALSE;
2302 fakeTrack[i] = kFALSE;
2304 //AliInfo("Selecting track candidates ...");
2306 // Sieve clusters in decreasing order of track quality
2307 Int_t jSieve(0), rejectedCandidates(0);
2309 // Check track candidates
2310 rejectedCandidates=0;
2311 for (Int_t itrack = 0; itrack < ntracks; itrack++) {
2312 Int_t trackIndex = sort[itrack];
2313 if (signedTrack[trackIndex] || fakeTrack[trackIndex]) continue;
2315 // Calculate track parameters from tracklets seeds
2320 for (Int_t jLayer = 0; jLayer < kNPlanes; jLayer++) {
2321 Int_t jseed = kNPlanes*trackIndex+jLayer;
2322 sseed[jseed].UpdateUsed();
2323 if(!sseed[jseed].IsOK()) continue;
2324 // check if primary candidate
2325 if (TMath::Abs(sseed[jseed].GetYref(0) / sseed[jseed].GetX0()) < 0.158) findable++;
2326 ncl += sseed[jseed].GetN();
2327 nused += sseed[jseed].GetNUsed();
2331 // Filter duplicated tracks
2333 AliDebug(4, Form("REJECTED : %d idx[%d] quality[%e] tracklets[%d] usedClusters[%d]", itrack, trackIndex, fTrackQuality[trackIndex], nlayers, nused));
2334 fakeTrack[trackIndex] = kTRUE;
2337 if (ncl>0 && Float_t(nused)/ncl >= .25){
2338 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));
2339 fakeTrack[trackIndex] = kTRUE;
2343 AliDebug(4, Form("Candidate[%d] Quality[%e] Tracklets[%d] Findable[%d] Ncl[%d] Nused[%d]", trackIndex, fTrackQuality[trackIndex], nlayers, findable, ncl, nused));
2346 Bool_t skip = kFALSE;
2348 case 0: // select 6 tracklets primary tracks, good quality
2349 if(nlayers > findable || nlayers < kNPlanes) {skip = kTRUE; break;}
2350 if(TMath::Log(1.E-9+fTrackQuality[trackIndex]) < -5.){skip = kTRUE; break;}
2353 case 1: // select shorter primary tracks, good quality
2354 //if(findable<4){skip = kTRUE; break;}
2355 if(nlayers < findable){skip = kTRUE; break;}
2356 if(TMath::Log(1.E-9+fTrackQuality[trackIndex]) < -4.){skip = kTRUE; break;}
2359 case 2: // select 6 tracklets secondary tracks
2360 if(nlayers < kNPlanes) { skip = kTRUE; break;}
2361 if (TMath::Log(1.E-9+fTrackQuality[trackIndex]) < -6.0){skip = kTRUE; break;}
2364 case 3: // select shorter tracks, good quality
2365 if (nlayers<4){skip = kTRUE; break;}
2366 if (TMath::Log(1.E-9+fTrackQuality[trackIndex]) < -5.){skip = kTRUE; break;}
2369 case 4: // select anything with at least 4 tracklets
2370 if (nlayers<4){skip = kTRUE; break;}
2371 //if (TMath::Log(1.E-9+fTrackQuality[trackIndex]) - nused/(nlayers-3.0) < -15.0){skip = kTRUE; break;}
2375 rejectedCandidates++;
2376 AliDebug(4, Form("REJECTED : %d idx[%d] quality[%e] tracklets[%d] usedClusters[%d]", itrack, trackIndex, fTrackQuality[trackIndex], nlayers, nused));
2378 } else AliDebug(4, Form("ACCEPTED : %d idx[%d] quality[%e] tracklets[%d] usedClusters[%d]", itrack, trackIndex, fTrackQuality[trackIndex], nlayers, nused));
2380 signedTrack[trackIndex] = kTRUE;
2382 AliTRDseedV1 *lseed =&sseed[trackIndex*kNPlanes];
2383 AliTRDtrackV1 *track = MakeTrack(lseed);
2385 AliDebug(1, "Track building failed.");
2388 if(AliLog::GetDebugLevel("TRD", "AliTRDtrackerV1") > 1){
2389 Int_t ich = 0; while(!(chamber = stack[ich])) ich++;
2390 AliDebug(2, Form("Track pt=%7.2fGeV/c SM[%2d] Done.", track->Pt(), fGeom->GetSector(chamber->GetDetector())));
2394 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) > 1 && fkReconstructor->IsDebugStreaming()){
2395 //AliInfo(Form("Track %d [%d] nlayers %d trackQuality = %e nused %d, yref = %3.3f", itrack, trackIndex, nlayers, fTrackQuality[trackIndex], nused, trackParams[1]));
2397 AliTRDseedV1 *dseed[6];
2398 for(Int_t iseed = AliTRDgeometry::kNlayer; iseed--;) dseed[iseed] = new AliTRDseedV1(lseed[iseed]);
2400 //Int_t eventNrInFile = esd->GetEventNumberInFile();
2401 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
2402 Int_t trackNumber = AliTRDtrackerDebug::GetTrackNumber();
2403 Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
2404 TTreeSRedirector &cstreamer = *fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker);
2405 cstreamer << "Clusters2TracksStack"
2406 << "EventNumber=" << eventNumber
2407 << "TrackNumber=" << trackNumber
2408 << "CandidateNumber=" << candidateNumber
2409 << "Iter=" << fSieveSeeding
2410 << "Like=" << fTrackQuality[trackIndex]
2411 << "S0.=" << dseed[0]
2412 << "S1.=" << dseed[1]
2413 << "S2.=" << dseed[2]
2414 << "S3.=" << dseed[3]
2415 << "S4.=" << dseed[4]
2416 << "S5.=" << dseed[5]
2418 << "NLayers=" << nlayers
2419 << "Findable=" << findable
2420 << "NUsed=" << nused
2425 AliESDtrack *esdTrack = new ((*esdTrackList)[ntracks0++]) AliESDtrack();
2426 esdTrack->UpdateTrackParams(track, AliESDtrack::kTRDout);
2427 esdTrack->SetLabel(track->GetLabel());
2428 track->UpdateESDtrack(esdTrack);
2429 // write ESD-friends if neccessary
2430 if (fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) > 0){
2431 AliTRDtrackV1 *calibTrack = new AliTRDtrackV1(*track);
2432 calibTrack->SetOwner();
2433 esdTrack->AddCalibObject(calibTrack);
2436 AliTRDtrackerDebug::SetTrackNumber(AliTRDtrackerDebug::GetTrackNumber() + 1);
2440 } while(jSieve<5 && rejectedCandidates); // end track candidates sieve
2441 if(!ntracks1) break;
2443 // increment counters
2444 ntracks2 += ntracks1;
2446 if(fkReconstructor->IsHLT()) break;
2449 // Rebuild plane configurations and indices taking only unused clusters into account
2450 quality = BuildSeedingConfigs(stack, configs);
2451 if(quality < 1.E-7) break; //fkReconstructor->GetRecoParam() ->GetPlaneQualityThreshold()) break;
2453 for(Int_t ip = 0; ip < kNPlanes; ip++){
2454 if(!(chamber = stack[ip])) continue;
2455 chamber->Build(fGeom);//Indices(fSieveSeeding);
2458 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) > 10){
2459 AliInfo(Form("Sieve level %d Plane config %d %d %d Quality %f", fSieveSeeding, configs[0], configs[1], configs[2], quality));
2461 } while(fSieveSeeding<10); // end stack clusters sieve
2465 //AliInfo(Form("Registered TRD tracks %d in stack %d.", ntracks2, pars[1]));
2470 //___________________________________________________________________
2471 Double_t AliTRDtrackerV1::BuildSeedingConfigs(AliTRDtrackingChamber **stack, Int_t *configs)
2474 // Assign probabilities to chambers according to their
2475 // capability of producing seeds.
2479 // layers : Array of stack propagation layers for all 6 chambers in one stack
2480 // configs : On exit array of configuration indexes (see GetSeedingConfig()
2481 // for details) in the decreasing order of their seeding probabilities.
2485 // Return top configuration quality
2487 // Detailed description:
2489 // To each chamber seeding configuration (see GetSeedingConfig() for
2490 // the list of all configurations) one defines 2 quality factors:
2491 // - an apriori topological quality (see GetSeedingConfig() for details) and
2492 // - a data quality based on the uniformity of the distribution of
2493 // clusters over the x range (time bins population). See CookChamberQA() for details.
2494 // The overall chamber quality is given by the product of this 2 contributions.
2497 Double_t chamberQ[kNPlanes];memset(chamberQ, 0, kNPlanes*sizeof(Double_t));
2498 AliTRDtrackingChamber *chamber = NULL;
2499 for(int iplane=0; iplane<kNPlanes; iplane++){
2500 if(!(chamber = stack[iplane])) continue;
2501 chamberQ[iplane] = (chamber = stack[iplane]) ? chamber->GetQuality() : 0.;
2504 Double_t tconfig[kNConfigs];memset(tconfig, 0, kNConfigs*sizeof(Double_t));
2505 Int_t planes[] = {0, 0, 0, 0};
2506 for(int iconf=0; iconf<kNConfigs; iconf++){
2507 GetSeedingConfig(iconf, planes);
2508 tconfig[iconf] = fgTopologicQA[iconf];
2509 for(int iplane=0; iplane<4; iplane++) tconfig[iconf] *= chamberQ[planes[iplane]];
2512 TMath::Sort((Int_t)kNConfigs, tconfig, configs, kTRUE);
2513 // AliInfo(Form("q[%d] = %f", configs[0], tconfig[configs[0]]));
2514 // AliInfo(Form("q[%d] = %f", configs[1], tconfig[configs[1]]));
2515 // AliInfo(Form("q[%d] = %f", configs[2], tconfig[configs[2]]));
2517 return tconfig[configs[0]];
2520 //____________________________________________________________________
2521 Int_t AliTRDtrackerV1::MakeSeeds(AliTRDtrackingChamber **stack, AliTRDseedV1 * const sseed, const Int_t * const ipar)
2524 // Seed tracklets and build candidate TRD tracks. The procedure is used during barrel tracking to account for tracks which are
2525 // either missed by TPC prolongation or conversions inside the TRD volume.
2526 // For stand alone tracking the procedure is used to estimate all tracks measured by TRD.
2529 // layers : Array of stack propagation layers containing clusters
2530 // sseed : Array of empty tracklet seeds. On exit they are filled.
2531 // ipar : Control parameters:
2532 // ipar[0] -> seeding chambers configuration
2533 // ipar[1] -> stack index
2534 // ipar[2] -> number of track candidates found so far
2537 // Number of tracks candidates found.
2539 // The following steps are performed:
2540 // 1. Build seeding layers by collapsing all time bins from each of the four seeding chambers along the
2541 // radial coordinate. See AliTRDtrackingChamber::GetSeedingLayer() for details. The chambers selection for seeding
2542 // is described in AliTRDtrackerV1::Clusters2TracksStack().
2543 // 2. Using the seeding clusters from the seeding layer (step 1) build combinatorics using the following algorithm:
2544 // - for each seeding cluster in the lower seeding layer find
2545 // - all seeding clusters in the upper seeding layer inside a road defined by a given phi angle. The angle
2546 // is calculated on the minimum pt of tracks from vertex accesible to the stand alone tracker.
2547 // - for each pair of two extreme seeding clusters select middle upper cluster using roads defined externally by the
2549 // - select last seeding cluster as the nearest to the linear approximation of the track described by the first three
2550 // seeding clusters.
2551 // The implementation of road calculation and cluster selection can be found in the functions AliTRDchamberTimeBin::BuildCond()
2552 // and AliTRDchamberTimeBin::GetClusters().
2553 // 3. Helix fit of the seeding clusters set. (see AliTRDtrackerFitter::FitRieman(AliTRDcluster**)). No tilt correction is
2554 // performed at this level
2555 // 4. Initialize seeding tracklets in the seeding chambers.
2556 // 5. *Filter 0* Chi2 cut on the Y and Z directions. The threshold is set externally by the reco params.
2557 // 6. Attach (true) clusters to seeding tracklets (see AliTRDseedV1::AttachClusters()) and fit tracklet (see
2558 // AliTRDseedV1::Fit()). The number of used clusters used by current seeds should not exceed ... (25).
2559 // 7. *Filter 1* Check if all 4 seeding tracklets are correctly constructed.
2560 // 8. Helix fit of the clusters from the seeding tracklets with tilt correction. Refit tracklets using the new
2561 // approximation of the track.
2562 // 9. *Filter 2* Calculate likelihood of the track. (See AliTRDtrackerV1::CookLikelihood()). The following quantities are
2563 // checked against the Riemann fit:
2564 // - position resolution in y
2565 // - angular resolution in the bending plane
2566 // - likelihood of the number of clusters attached to the tracklet
2567 // 10. Extrapolation of the helix fit to the other 2 chambers *non seeding* chambers:
2568 // - Initialization of extrapolation tracklets with the fit parameters
2569 // - Attach clusters to extrapolated tracklets
2570 // - Helix fit of tracklets
2571 // 11. Improve seeding tracklets quality by reassigning clusters based on the last parameters of the track
2572 // See AliTRDtrackerV1::ImproveSeedQuality() for details.
2573 // 12. Helix fit of all 6 seeding tracklets and chi2 calculation
2574 // 13. Hyperplane fit and track quality calculation. See AliTRDtrackerFitter::FitHyperplane() for details.
2575 // 14. Cooking labels for tracklets. Should be done only for MC
2576 // 15. Register seeds.
2579 // Marian Ivanov <M.Ivanov@gsi.de>
2580 // Alexandru Bercuci <A.Bercuci@gsi.de>
2581 // Markus Fasel <M.Fasel@gsi.de>
2583 AliTRDtrackingChamber *chamber = NULL;
2584 AliTRDcluster *c[kNSeedPlanes] = {NULL, NULL, NULL, NULL}; // initilize seeding clusters
2585 AliTRDseedV1 *cseed = &sseed[0]; // initialize tracklets for first track
2586 Int_t ncl, mcl; // working variable for looping over clusters
2587 Int_t index[AliTRDchamberTimeBin::kMaxClustersLayer], jndex[AliTRDchamberTimeBin::kMaxClustersLayer];
2589 // chi2[0] = tracklet chi2 on the Z direction
2590 // chi2[1] = tracklet chi2 on the R direction
2593 // this should be data member of AliTRDtrack TODO
2594 Double_t seedQuality[kMaxTracksStack];
2596 // unpack control parameters
2597 Int_t config = ipar[0];
2598 Int_t ntracks = ipar[1];
2599 Int_t istack = ipar[2];
2600 Int_t planes[kNSeedPlanes]; GetSeedingConfig(config, planes);
2601 Int_t planesExt[kNPlanes-kNSeedPlanes]; GetExtrapolationConfig(config, planesExt);
2604 // Init chambers geometry
2605 Double_t hL[kNPlanes]; // Tilting angle
2606 Float_t padlength[kNPlanes]; // pad lenghts
2607 Float_t padwidth[kNPlanes]; // pad widths
2608 AliTRDpadPlane *pp = NULL;
2609 for(int iplane=0; iplane<kNPlanes; iplane++){
2610 pp = fGeom->GetPadPlane(iplane, istack);
2611 hL[iplane] = TMath::Tan(TMath::DegToRad()*pp->GetTiltingAngle());
2612 padlength[iplane] = pp->GetLengthIPad();
2613 padwidth[iplane] = pp->GetWidthIPad();
2616 // Init anode wire position for chambers
2617 Double_t x0[kNPlanes], // anode wire position
2618 driftLength = .5*AliTRDgeometry::AmThick() - AliTRDgeometry::DrThick(); // drift length
2619 TGeoHMatrix *matrix = NULL;
2620 Double_t loc[] = {AliTRDgeometry::AnodePos(), 0., 0.};
2621 Double_t glb[] = {0., 0., 0.};
2622 AliTRDtrackingChamber **cIter = &stack[0];
2623 for(int iLayer=0; iLayer<kNPlanes; iLayer++,cIter++){
2624 if(!(*cIter)) continue;
2625 if(!(matrix = fGeom->GetClusterMatrix((*cIter)->GetDetector()))){
2626 x0[iLayer] = fgkX0[iLayer];
2629 matrix->LocalToMaster(loc, glb);
2630 x0[iLayer] = glb[0];
2633 AliDebug(2, Form("Making seeds Stack[%d] Config[%d] Tracks[%d]...", istack, config, ntracks));
2635 // Build seeding layers
2638 for(int isl=0; isl<kNSeedPlanes; isl++){
2639 if(!(chamber = stack[planes[isl]])) continue;
2640 if(!chamber->GetSeedingLayer(fSeedTB[isl], fGeom, fkReconstructor)) continue;
2643 if(nlayers < kNSeedPlanes) return ntracks;
2646 // Start finding seeds
2647 Double_t cond0[4], cond1[4], cond2[4];
2649 while((c[3] = (*fSeedTB[3])[icl++])){
2651 fSeedTB[0]->BuildCond(c[3], cond0, 0);
2652 fSeedTB[0]->GetClusters(cond0, index, ncl);
2653 //printf("Found c[3] candidates 0 %d\n", ncl);
2656 c[0] = (*fSeedTB[0])[index[jcl++]];
2658 Double_t dx = c[3]->GetX() - c[0]->GetX();
2659 Double_t dzdx = (c[3]->GetZ() - c[0]->GetZ())/dx;
2660 Double_t dydx = (c[3]->GetY() - c[0]->GetY())/dx;
2661 fSeedTB[1]->BuildCond(c[0], cond1, 1, dzdx, dydx);
2662 fSeedTB[1]->GetClusters(cond1, jndex, mcl);
2663 //printf("Found c[0] candidates 1 %d\n", mcl);
2667 c[1] = (*fSeedTB[1])[jndex[kcl++]];
2669 fSeedTB[2]->BuildCond(c[1], cond2, 2, dzdx, dydx);
2670 c[2] = fSeedTB[2]->GetNearestCluster(cond2);
2671 //printf("Found c[1] candidate 2 %p\n", c[2]);
2674 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].",
2675 c[0]->GetX(), c[0]->GetY(), c[0]->GetZ(),
2676 c[1]->GetX(), c[1]->GetY(), c[1]->GetZ(),
2677 c[2]->GetX(), c[2]->GetY(), c[2]->GetZ(),
2678 c[3]->GetX(), c[3]->GetY(), c[3]->GetZ()));
2680 for (Int_t il = 0; il < kNPlanes; il++) cseed[il].Reset();
2684 AliTRDseedV1 *tseed = &cseed[0];
2686 for(int iLayer=0; iLayer<kNPlanes; iLayer++, tseed++, cIter++){
2687 Int_t det = (*cIter) ? (*cIter)->GetDetector() : -1;
2688 tseed->SetDetector(det);
2689 tseed->SetTilt(hL[iLayer]);
2690 tseed->SetPadLength(padlength[iLayer]);
2691 tseed->SetPadWidth(padwidth[iLayer]);
2692 tseed->SetReconstructor(fkReconstructor);
2693 tseed->SetX0(det<0 ? fR[iLayer]+driftLength : x0[iLayer]);
2694 tseed->Init(GetRiemanFitter());
2695 tseed->SetStandAlone(kTRUE);
2698 Bool_t isFake = kFALSE;
2699 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) >= 2 && fkReconstructor->IsDebugStreaming()){
2700 if (c[0]->GetLabel(0) != c[3]->GetLabel(0)) isFake = kTRUE;
2701 if (c[1]->GetLabel(0) != c[3]->GetLabel(0)) isFake = kTRUE;
2702 if (c[2]->GetLabel(0) != c[3]->GetLabel(0)) isFake = kTRUE;
2705 for(Int_t l = 0; l < kNSeedPlanes; l++) xpos[l] = fSeedTB[l]->GetX();
2707 for(int il=0; il<4; il++) yref[il] = cseed[planes[il]].GetYref(0);
2708 Int_t ll = c[3]->GetLabel(0);
2709 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
2710 Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
2711 AliRieman *rim = GetRiemanFitter();
2712 TTreeSRedirector &cs0 = *fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker);
2714 <<"EventNumber=" << eventNumber
2715 <<"CandidateNumber=" << candidateNumber
2716 <<"isFake=" << isFake
2717 <<"config=" << config
2719 <<"chi2z=" << chi2[0]
2720 <<"chi2y=" << chi2[1]
2721 <<"Y2exp=" << cond2[0]
2722 <<"Z2exp=" << cond2[1]
2723 <<"X0=" << xpos[0] //layer[sLayer]->GetX()
2724 <<"X1=" << xpos[1] //layer[sLayer + 1]->GetX()
2725 <<"X2=" << xpos[2] //layer[sLayer + 2]->GetX()
2726 <<"X3=" << xpos[3] //layer[sLayer + 3]->GetX()
2727 <<"yref0=" << yref[0]
2728 <<"yref1=" << yref[1]
2729 <<"yref2=" << yref[2]
2730 <<"yref3=" << yref[3]
2735 <<"Seed0.=" << &cseed[planes[0]]
2736 <<"Seed1.=" << &cseed[planes[1]]
2737 <<"Seed2.=" << &cseed[planes[2]]
2738 <<"Seed3.=" << &cseed[planes[3]]
2739 <<"RiemanFitter.=" << rim
2742 if(chi2[0] > fkRecoParam->GetChi2Z()/*7./(3. - sLayer)*//*iter*/){
2743 AliDebug(3, Form("Filter on chi2Z [%f].", chi2[0]));
2744 AliTRDtrackerDebug::SetCandidateNumber(AliTRDtrackerDebug::GetCandidateNumber() + 1);
2747 if(chi2[1] > fkRecoParam->GetChi2Y()/*1./(3. - sLayer)*//*iter*/){
2748 AliDebug(3, Form("Filter on chi2Y [%f].", chi2[1]));
2749 AliTRDtrackerDebug::SetCandidateNumber(AliTRDtrackerDebug::GetCandidateNumber() + 1);
2752 //AliInfo("Passed chi2 filter.");
2754 // try attaching clusters to tracklets
2756 AliTRDcluster *cl = NULL;
2757 for(int iLayer=0; iLayer<kNSeedPlanes; iLayer++){
2758 Int_t jLayer = planes[iLayer];
2759 Int_t nNotInChamber = 0;
2760 if(!cseed[jLayer].AttachClusters(stack[jLayer], kTRUE)) continue;
2761 if(/*fkReconstructor->IsHLT()*/kFALSE){
2762 cseed[jLayer].UpdateUsed();
2763 if(!cseed[jLayer].IsOK()) continue;
2765 cseed[jLayer].Fit();
2766 cseed[jLayer].UpdateUsed();
2767 cseed[jLayer].ResetClusterIter();
2768 while((cl = cseed[jLayer].NextCluster())){
2769 if(!cl->IsInChamber()) nNotInChamber++;
2771 //printf("clusters[%d], used[%d], not in chamber[%d]\n", cseed[jLayer].GetN(), cseed[jLayer].GetNUsed(), nNotInChamber);
2772 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
2777 if(mlayers < kNSeedPlanes){
2778 AliDebug(2, Form("Found only %d tracklets out of %d. Skip.", mlayers, kNSeedPlanes));
2779 AliTRDtrackerDebug::SetCandidateNumber(AliTRDtrackerDebug::GetCandidateNumber() + 1);
2783 // temporary exit door for the HLT
2784 if(fkReconstructor->IsHLT()){
2785 // attach clusters to extrapolation chambers
2786 for(int iLayer=0; iLayer<kNPlanes-kNSeedPlanes; iLayer++){
2787 Int_t jLayer = planesExt[iLayer];
2788 if(!(chamber = stack[jLayer])) continue;
2789 if(!cseed[jLayer].AttachClusters(chamber, kTRUE)) continue;
2790 cseed[jLayer].Fit();
2792 //FitTiltedRiemanConstraint(&cseed[0], GetZ());
2793 fTrackQuality[ntracks] = 1.; // dummy value
2795 if(ntracks == kMaxTracksStack) return ntracks;
2801 // Update Seeds and calculate Likelihood
2802 // fit tracklets and cook likelihood
2803 Double_t chi2Vals[4];
2804 chi2Vals[0] = FitTiltedRieman(&cseed[0], kTRUE);
2805 for(int iLayer=0; iLayer<kNSeedPlanes; iLayer++){
2806 Int_t jLayer = planes[iLayer];
2807 cseed[jLayer].Fit(1);
2809 Double_t like = CookLikelihood(&cseed[0], planes); // to be checked
2811 if (TMath::Log(1.E-9 + like) < fkRecoParam->GetTrackLikelihood()){
2812 AliDebug(3, Form("Filter on likelihood %f[%e].", TMath::Log(1.E-9 + like), like));
2813 AliTRDtrackerDebug::SetCandidateNumber(AliTRDtrackerDebug::GetCandidateNumber() + 1);
2816 //AliInfo(Form("Passed likelihood %f[%e].", TMath::Log(1.E-9 + like), like));
2818 // book preliminary results
2819 seedQuality[ntracks] = like;
2820 fSeedLayer[ntracks] = config;/*sLayer;*/
2822 // attach clusters to the extrapolation seeds
2824 for(int iLayer=0; iLayer<kNPlanes-kNSeedPlanes; iLayer++){
2825 Int_t jLayer = planesExt[iLayer];
2826 if(!(chamber = stack[jLayer])) continue;
2828 // fit extrapolated seed
2829 if ((jLayer == 0) && !(cseed[1].IsOK())) continue;
2830 if ((jLayer == 5) && !(cseed[4].IsOK())) continue;
2831 AliTRDseedV1 pseed = cseed[jLayer];
2832 if(!pseed.AttachClusters(chamber, kTRUE)) continue;
2834 cseed[jLayer] = pseed;
2835 chi2Vals[0] = FitTiltedRieman(cseed, kTRUE);
2836 cseed[jLayer].Fit(1);
2840 // AliInfo("Extrapolation done.");
2841 // Debug Stream containing all the 6 tracklets
2842 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) >= 2 && fkReconstructor->IsDebugStreaming()){
2843 TTreeSRedirector &cstreamer = *fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker);
2844 TLinearFitter *tiltedRieman = GetTiltedRiemanFitter();
2845 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
2846 Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
2847 cstreamer << "MakeSeeds1"
2848 << "EventNumber=" << eventNumber
2849 << "CandidateNumber=" << candidateNumber
2850 << "S0.=" << &cseed[0]
2851 << "S1.=" << &cseed[1]
2852 << "S2.=" << &cseed[2]
2853 << "S3.=" << &cseed[3]
2854 << "S4.=" << &cseed[4]
2855 << "S5.=" << &cseed[5]
2856 << "FitterT.=" << tiltedRieman
2860 if(fkRecoParam->HasImproveTracklets()){
2861 if(!ImproveSeedQuality(stack, cseed, chi2Vals[0])){
2862 AliTRDtrackerDebug::SetCandidateNumber(AliTRDtrackerDebug::GetCandidateNumber() + 1);
2863 AliDebug(3, "ImproveSeedQuality() failed.");
2867 // do track fitting with vertex constraint
2868 if(fkRecoParam->IsVertexConstrained()) chi2Vals[1] = FitTiltedRiemanConstraint(&cseed[0], GetZ());
2869 else chi2Vals[1] = -1.;
2870 chi2Vals[2] = GetChi2Z(&cseed[0]);
2871 chi2Vals[3] = GetChi2Phi(&cseed[0]);
2873 // calculate track quality
2874 fTrackQuality[ntracks] = CalculateTrackLikelihood(&chi2Vals[0]);
2876 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) >= 2 && fkReconstructor->IsDebugStreaming()){
2877 TTreeSRedirector &cstreamer = *fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker);
2878 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
2879 Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
2880 TLinearFitter *fitterTC = GetTiltedRiemanFitterConstraint();
2881 TLinearFitter *fitterT = GetTiltedRiemanFitter();
2883 for(Int_t iseed = 0; iseed < kNPlanes; iseed++){
2884 ncls += cseed[iseed].IsOK() ? cseed[iseed].GetN2() : 0;
2886 cstreamer << "MakeSeeds2"
2887 << "EventNumber=" << eventNumber
2888 << "CandidateNumber=" << candidateNumber
2889 << "Chi2TR=" << chi2Vals[0]
2890 << "Chi2TC=" << chi2Vals[1]
2891 << "Nlayers=" << mlayers
2892 << "NClusters=" << ncls
2894 << "S0.=" << &cseed[0]
2895 << "S1.=" << &cseed[1]
2896 << "S2.=" << &cseed[2]
2897 << "S3.=" << &cseed[3]
2898 << "S4.=" << &cseed[4]
2899 << "S5.=" << &cseed[5]
2900 << "FitterT.=" << fitterT
2901 << "FitterTC.=" << fitterTC
2904 if(AliLog::GetDebugLevel("TRD", "AliTRDtrackerV1")){
2905 Double_t pt[]={0., 0.};
2906 for(Int_t il(0); il<kNPlanes; il++){
2907 if(!cseed[il].IsOK()) continue;
2908 pt[0] = GetBz()*kB2C/cseed[il].GetC();
2909 pt[1] = GetBz()*kB2C/cseed[il].GetC(1);
2912 AliDebug(2, Form("Candidate[%2d] pt[%7.3f %7.3f] Q[%e]\n"
2913 " [0] x[%6.2f] n[%2d] nu[%d] OK[%c]\n"
2914 " [1] x[%6.2f] n[%2d] nu[%d] OK[%c]\n"
2915 " [2] x[%6.2f] n[%2d] nu[%d] OK[%c]\n"
2916 " [3] x[%6.2f] n[%2d] nu[%d] OK[%c]\n"
2917 " [4] x[%6.2f] n[%2d] nu[%d] OK[%c]\n"
2918 " [5] x[%6.2f] n[%2d] nu[%d] OK[%c]"
2919 , ntracks, pt[0], pt[1], fTrackQuality[ntracks]
2920 ,cseed[0].GetX(), cseed[0].GetN(), cseed[0].GetNUsed(), cseed[0].IsOK()?'y':'n'
2921 ,cseed[1].GetX(), cseed[1].GetN(), cseed[1].GetNUsed(), cseed[1].IsOK()?'y':'n'
2922 ,cseed[2].GetX(), cseed[2].GetN(), cseed[2].GetNUsed(), cseed[2].IsOK()?'y':'n'
2923 ,cseed[3].GetX(), cseed[3].GetN(), cseed[3].GetNUsed(), cseed[3].IsOK()?'y':'n'
2924 ,cseed[4].GetX(), cseed[4].GetN(), cseed[4].GetNUsed(), cseed[4].IsOK()?'y':'n'
2925 ,cseed[5].GetX(), cseed[5].GetN(), cseed[5].GetNUsed(), cseed[5].IsOK()?'y':'n'));
2928 AliTRDtrackerDebug::SetCandidateNumber(AliTRDtrackerDebug::GetCandidateNumber() + 1);
2929 if(ntracks == kMaxTracksStack){
2930 AliWarning(Form("Number of seeds reached maximum allowed (%d) in stack.", kMaxTracksStack));
2941 //_____________________________________________________________________________
2942 AliTRDtrackV1* AliTRDtrackerV1::MakeTrack(AliTRDseedV1 * const tracklet)
2945 // Build a TRD track out of tracklet candidates
2948 // seeds : array of tracklets
2949 // params : array of track parameters as they are estimated by stand alone tracker. 7 elements.
2950 // [0] - radial position of the track at reference point
2951 // [1] - y position of the fit at [0]
2952 // [2] - z position of the fit at [0]
2953 // [3] - snp of the first tracklet
2954 // [4] - tgl of the first tracklet
2955 // [5] - curvature of the Riemann fit - 1/pt
2956 // [6] - sector rotation angle
2961 // Initialize the TRD track based on the parameters of the fit and a parametric covariance matrix
2962 // (diagonal with constant variance terms TODO - correct parameterization)
2964 // In case of HLT just register the tracklets in the tracker and return values of the Riemann fit. For the
2965 // offline case perform a full Kalman filter on the already found tracklets (see AliTRDtrackerV1::FollowBackProlongation()
2966 // for details). Do also MC label calculation and PID if propagation successfully.
2968 if(fkReconstructor->IsHLT()) FitTiltedRiemanConstraint(tracklet, 0);
2969 Double_t alpha = AliTRDgeometry::GetAlpha();
2970 Double_t shift = AliTRDgeometry::GetAlpha()/2.0;
2972 // find first good tracklet
2973 Int_t idx(0); while(idx<kNPlanes && !tracklet[idx].IsOK()) idx++;
2974 if(idx>2){ AliDebug(1, Form("Found suspect track start @ layer idx[%d]\n"
2975 " %c[0] x0[%f] n[%d] nu[%d] OK[%c]\n"
2976 " %c[1] x0[%f] n[%d] nu[%d] OK[%c]\n"
2977 " %c[2] x0[%f] n[%d] nu[%d] OK[%c]\n"
2978 " %c[3] x0[%f] n[%d] nu[%d] OK[%c]\n"
2979 " %c[4] x0[%f] n[%d] nu[%d] OK[%c]\n"
2980 " %c[5] x0[%f] n[%d] nu[%d] OK[%c]"
2982 ,idx==0?'*':' ', tracklet[0].GetX0(), tracklet[0].GetN(), tracklet[0].GetNUsed(), tracklet[0].IsOK()?'y':'n'
2983 ,idx==1?'*':' ', tracklet[1].GetX0(), tracklet[1].GetN(), tracklet[1].GetNUsed(), tracklet[1].IsOK()?'y':'n'
2984 ,idx==2?'*':' ', tracklet[2].GetX0(), tracklet[2].GetN(), tracklet[2].GetNUsed(), tracklet[2].IsOK()?'y':'n'
2985 ,idx==3?'*':' ', tracklet[3].GetX0(), tracklet[3].GetN(), tracklet[3].GetNUsed(), tracklet[3].IsOK()?'y':'n'
2986 ,idx==4?'*':' ', tracklet[4].GetX0(), tracklet[4].GetN(), tracklet[4].GetNUsed(), tracklet[4].IsOK()?'y':'n'
2987 ,idx==5?'*':' ', tracklet[5].GetX0(), tracklet[5].GetN(), tracklet[5].GetNUsed(), tracklet[5].IsOK()?'y':'n'));
2992 Double_t x(tracklet[idx].GetX0() - dx);
2993 // Build track parameters
2994 Double_t params[] = {
2995 tracklet[idx].GetYref(0) - dx*tracklet[idx].GetYref(1) // y
2996 ,tracklet[idx].GetZref(0) - dx*tracklet[idx].GetZref(1) // z
2997 ,TMath::Sin(TMath::ATan(tracklet[idx].GetYref(1))) // snp
2998 ,tracklet[idx].GetZref(1) / TMath::Sqrt(1. + tracklet[idx].GetYref(1) * tracklet[idx].GetYref(1)) // tgl
2999 ,tracklet[idx].GetC(fkReconstructor->IsHLT()?1:0) // curvature -> 1/pt
3001 Int_t sector(fGeom->GetSector(tracklet[idx].GetDetector()));
3004 c[ 0] = 0.2; // s^2_y
3005 c[ 1] = 0.0; c[ 2] = 2.0; // s^2_z
3006 c[ 3] = 0.0; c[ 4] = 0.0; c[ 5] = 0.02; // s^2_snp
3007 c[ 6] = 0.0; c[ 7] = 0.0; c[ 8] = 0.0; c[ 9] = 0.1; // s^2_tgl
3008 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
3010 AliTRDtrackV1 track(tracklet, params, c, x, sector*alpha+shift);
3012 AliTRDseedV1 *ptrTracklet = NULL;
3014 // skip Kalman filter for HLT
3015 if(/*fkReconstructor->IsHLT()*/kFALSE){
3016 for (Int_t jLayer = 0; jLayer < AliTRDgeometry::kNlayer; jLayer++) {
3017 track.UnsetTracklet(jLayer);
3018 ptrTracklet = &tracklet[jLayer];
3019 if(!ptrTracklet->IsOK()) continue;
3020 if(TMath::Abs(ptrTracklet->GetYref(1) - ptrTracklet->GetYfit(1)) >= .2) continue; // check this condition with Marian
3021 ptrTracklet = SetTracklet(ptrTracklet);
3022 ptrTracklet->UseClusters();
3023 track.SetTracklet(ptrTracklet, fTracklets->GetEntriesFast()-1);
3025 AliTRDtrackV1 *ptrTrack = SetTrack(&track);
3026 ptrTrack->CookPID();
3027 ptrTrack->CookLabel(.9);
3028 ptrTrack->SetReconstructor(fkReconstructor);
3032 // prevent the error message in AliTracker::MeanMaterialBudget: "start point out of geometry"
3033 if(TMath::Abs(track.GetX()) + TMath::Abs(track.GetY()) + TMath::Abs(track.GetZ()) > 10000) return NULL;
3035 track.ResetCovariance(1);
3036 Int_t nc = TMath::Abs(FollowBackProlongation(track));
3037 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) > 5 && fkReconstructor->IsDebugStreaming()){
3038 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
3039 Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
3040 Double_t p[5]; // Track Params for the Debug Stream
3041 track.GetExternalParameters(x, p);
3042 TTreeSRedirector &cs = *fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker);
3044 << "EventNumber=" << eventNumber
3045 << "CandidateNumber=" << candidateNumber
3053 << "Yin=" << params[0]
3054 << "Zin=" << params[1]
3055 << "snpin=" << params[2]
3056 << "tndin=" << params[3]
3057 << "crvin=" << params[4]
3058 << "track.=" << &track
3062 UnsetTrackletsTrack(&track);
3065 AliTRDtrackV1 *ptrTrack = SetTrack(&track);
3066 ptrTrack->SetReconstructor(fkReconstructor);
3067 ptrTrack->CookLabel(.9);
3068 for(Int_t il(kNPlanes); il--;){
3069 if(!(ptrTracklet = ptrTrack->GetTracklet(il))) continue;
3070 ptrTracklet->UseClusters();
3073 // computes PID for track
3074 ptrTrack->CookPID();
3075 // update calibration references using this track
3076 AliTRDCalibraFillHisto *calibra = AliTRDCalibraFillHisto::Instance();
3078 AliInfo("Could not get Calibra instance.");
3079 } else if(calibra->GetHisto2d()){
3080 calibra->UpdateHistogramsV1(ptrTrack);
3086 //____________________________________________________________________
3087 Bool_t AliTRDtrackerV1::ImproveSeedQuality(AliTRDtrackingChamber **stack, AliTRDseedV1 *cseed, Double_t &chi2)
3090 // Sort tracklets according to "quality" and try to "improve" the first 4 worst
3093 // layers : Array of propagation layers for a stack/supermodule
3094 // cseed : Array of 6 seeding tracklets which has to be improved
3097 // cssed : Improved seeds
3099 // Detailed description
3101 // Iterative procedure in which new clusters are searched for each
3102 // tracklet seed such that the seed quality (see AliTRDseed::GetQuality())
3103 // can be maximized. If some optimization is found the old seeds are replaced.
3108 // make a local working copy
3109 AliTRDtrackingChamber *chamber = NULL;
3110 AliTRDseedV1 bseed[AliTRDgeometry::kNlayer];
3112 Float_t quality(1.e3),
3113 lQuality[AliTRDgeometry::kNlayer] = {1.e3, 1.e3, 1.e3, 1.e3, 1.e3, 1.e3};
3115 for(Int_t jLayer=AliTRDgeometry::kNlayer; jLayer--;){
3116 bseed[jLayer] = cseed[jLayer];
3117 if(!bseed[jLayer].IsOK()) continue;
3119 lQuality[jLayer] = bseed[jLayer].GetQuality(kTRUE);
3120 quality += lQuality[jLayer];
3123 AliDebug(2, Form("Start N[%d] Q[%f] chi2[%f]", rLayers, quality, chi2));
3125 for (Int_t iter = 0; iter < 4; iter++) {
3126 // Try better cluster set
3127 Int_t nLayers(0); Float_t qualitynew(0.);
3128 Int_t indexes[4*AliTRDgeometry::kNlayer];
3129 TMath::Sort(Int_t(AliTRDgeometry::kNlayer), lQuality, indexes, kFALSE);
3130 for(Int_t jLayer=AliTRDgeometry::kNlayer; jLayer--;) {
3131 Int_t bLayer = indexes[jLayer];
3132 bseed[bLayer].Reset("c");
3133 if(!(chamber = stack[bLayer])) continue;
3134 if(!bseed[bLayer].AttachClusters(chamber, kTRUE)) continue;
3135 bseed[bLayer].Fit(1);
3136 if(!bseed[bLayer].IsOK()) continue;
3138 lQuality[jLayer] = bseed[jLayer].GetQuality(kTRUE);
3139 qualitynew += lQuality[jLayer];
3141 if(rLayers > nLayers){
3142 AliDebug(1, Form("Lost %d tracklets while improving.", rLayers-nLayers));
3143 return iter>0?kTRUE:kFALSE;
3144 } else rLayers=nLayers;
3145 qualitynew /= rLayers;
3147 if(qualitynew > quality){
3148 AliDebug(4, Form("Quality[%f] worsen in iter[%d] to ref[%f].", qualitynew, iter, quality));
3149 return iter>0?kTRUE:kFALSE;
3150 } else quality = qualitynew;
3152 // try improve track parameters
3153 Float_t chi2new = FitTiltedRieman(bseed, kTRUE);
3155 AliDebug(4, Form("Chi2[%f] worsen in iter[%d] to ref[%f].", chi2new, iter, chi2));
3156 return iter>0?kTRUE:kFALSE;
3157 } else chi2 = chi2new;
3159 // store better tracklets
3160 for(Int_t jLayer=AliTRDgeometry::kNlayer; jLayer--;) cseed[jLayer]=bseed[jLayer];
3161 AliDebug(2, Form("Iter[%d] Q[%f] chi2[%f]", iter, quality, chi2));
3164 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) >= 7 && fkReconstructor->IsDebugStreaming()){
3165 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
3166 Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
3167 TLinearFitter *tiltedRieman = GetTiltedRiemanFitter();
3168 TTreeSRedirector &cstreamer = *fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker);
3169 cstreamer << "ImproveSeedQuality"
3170 << "EventNumber=" << eventNumber
3171 << "CandidateNumber=" << candidateNumber
3172 << "Iteration=" << iter
3173 << "S0.=" << &cseed[0]
3174 << "S1.=" << &cseed[1]
3175 << "S2.=" << &cseed[2]
3176 << "S3.=" << &cseed[3]
3177 << "S4.=" << &cseed[4]
3178 << "S5.=" << &cseed[5]
3179 << "FitterT.=" << tiltedRieman
3184 // we are sure that at least 4 tracklets are OK !
3188 //_________________________________________________________________________
3189 Double_t AliTRDtrackerV1::CalculateTrackLikelihood(Double_t *chi2){
3191 // Calculates the Track Likelihood value. This parameter serves as main quality criterion for
3192 // the track selection
3193 // The likelihood value containes:
3194 // - The chi2 values from the both fitters and the chi2 values in z-direction from a linear fit
3195 // - The Sum of the Parameter |slope_ref - slope_fit|/Sigma of the tracklets
3196 // For all Parameters an exponential dependency is used
3198 // Parameters: - Array of tracklets (AliTRDseedV1) related to the track candidate
3199 // - Array of chi2 values:
3200 // * Non-Constrained Tilted Riemann fit
3201 // * Vertex-Constrained Tilted Riemann fit
3202 // * z-Direction from Linear fit
3203 // Output: - The calculated track likelihood
3208 // Non-constrained Tilted Riemann
3209 Double_t likeChi2TR = TMath::Exp(-chi2[0] * 0.0078);
3210 // Constrained Tilted Riemann
3211 Double_t likeChi2TC(1.);
3213 likeChi2TC = TMath::Exp(-chi2[1] * 0.677);
3214 Double_t r = likeChi2TC/likeChi2TR;
3215 if(r>1.e2){;} // -> a primary track use TC
3216 else if(r<1.e2) // -> a secondary track use TR
3218 else{;} // -> test not conclusive
3220 // Chi2 only on Z direction
3221 Double_t likeChi2Z = TMath::Exp(-chi2[2] * 0.14);
3222 // Chi2 angular resolution
3223 Double_t likeChi2Phi= TMath::Exp(-chi2[3] * 3.23);
3225 Double_t trackLikelihood = likeChi2Z * likeChi2TR * likeChi2TC * likeChi2Phi;
3227 AliDebug(2, Form("Likelihood [%e]\n"
3228 " Rieman : chi2[%f] likelihood[%6.2e]\n"
3229 " Vertex : chi2[%f] likelihood[%6.2e]\n"
3230 " Z : chi2[%f] likelihood[%6.2e]\n"
3231 " Phi : chi2[%f] likelihood[%6.2e]"
3233 , chi2[0], likeChi2TR
3234 , chi2[1], likeChi2TC
3235 , chi2[2], likeChi2Z
3236 , chi2[3], likeChi2Phi
3239 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) >= 2 && fkReconstructor->IsDebugStreaming()){
3240 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
3241 Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
3242 TTreeSRedirector &cstreamer = *fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker);
3243 cstreamer << "CalculateTrackLikelihood0"
3244 << "EventNumber=" << eventNumber
3245 << "CandidateNumber=" << candidateNumber
3246 << "LikeChi2Z=" << likeChi2Z
3247 << "LikeChi2TR=" << likeChi2TR
3248 << "LikeChi2TC=" << likeChi2TC
3249 << "LikeChi2Phi=" << likeChi2Phi
3250 << "TrackLikelihood=" << trackLikelihood
3254 return trackLikelihood;
3257 //____________________________________________________________________
3258 Double_t AliTRDtrackerV1::CookLikelihood(AliTRDseedV1 *cseed, Int_t planes[4])
3261 // Calculate the probability of this track candidate.
3264 // cseeds : array of candidate tracklets
3265 // planes : array of seeding planes (see seeding configuration)
3266 // chi2 : chi2 values (on the Z and Y direction) from the rieman fit of the track.
3271 // Detailed description
3273 // The track quality is estimated based on the following 4 criteria:
3274 // 1. precision of the rieman fit on the Y direction (likea)
3275 // 2. chi2 on the Y direction (likechi2y)
3276 // 3. chi2 on the Z direction (likechi2z)
3277 // 4. number of attached clusters compared to a reference value
3278 // (see AliTRDrecoParam::fkFindable) (likeN)
3280 // The distributions for each type of probabilities are given below as of
3281 // (date). They have to be checked to assure consistency of estimation.
3284 // ratio of the total number of clusters/track which are expected to be found by the tracker.
3285 Double_t chi2y = GetChi2Y(&cseed[0]);
3286 Double_t chi2z = GetChi2Z(&cseed[0]);
3288 Float_t nclusters = 0.;
3289 Double_t sumda = 0.;
3290 for(UChar_t ilayer = 0; ilayer < 4; ilayer++){
3291 Int_t jlayer = planes[ilayer];
3292 nclusters += cseed[jlayer].GetN2();
3293 sumda += TMath::Abs(cseed[jlayer].GetYfit(1) - cseed[jlayer].GetYref(1));
3297 Double_t likea = TMath::Exp(-sumda * fkRecoParam->GetPhiSlope());
3298 Double_t likechi2y = 0.0000000001;
3299 if (fkReconstructor->IsCosmic() || chi2y < fkRecoParam->GetChi2YCut()) likechi2y += TMath::Exp(-TMath::Sqrt(chi2y) * fkRecoParam->GetChi2YSlope());
3300 Double_t likechi2z = TMath::Exp(-chi2z * fkRecoParam->GetChi2ZSlope());
3301 Double_t likeN = TMath::Exp(-(fkRecoParam->GetNMeanClusters() - nclusters) / fkRecoParam->GetNSigmaClusters());
3302 Double_t like = likea * likechi2y * likechi2z * likeN;
3304 if(fkRecoParam->GetStreamLevel(AliTRDrecoParam::kTracker) >= 2 && fkReconstructor->IsDebugStreaming()){
3305 Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
3306 Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
3307 Int_t nTracklets = 0; Float_t meanNcls = 0;
3308 for(Int_t iseed=0; iseed < kNPlanes; iseed++){
3309 if(!cseed[iseed].IsOK()) continue;
3311 meanNcls += cseed[iseed].GetN2();
3313 if(nTracklets) meanNcls /= nTracklets;
3314 // The Debug Stream contains the seed
3315 TTreeSRedirector &cstreamer = *fkReconstructor->GetDebugStream(AliTRDrecoParam::kTracker);
3316 cstreamer << "CookLikelihood"
3317 << "EventNumber=" << eventNumber
3318 << "CandidateNumber=" << candidateNumber
3319 << "tracklet0.=" << &cseed[0]
3320 << "tracklet1.=" << &cseed[1]
3321 << "tracklet2.=" << &cseed[2]
3322 << "tracklet3.=" << &cseed[3]
3323 << "tracklet4.=" << &cseed[4]
3324 << "tracklet5.=" << &cseed[5]
3325 << "sumda=" << sumda
3326 << "chi2y=" << chi2y
3327 << "chi2z=" << chi2z
3328 << "likea=" << likea
3329 << "likechi2y=" << likechi2y
3330 << "likechi2z=" << likechi2z
3331 << "nclusters=" << nclusters
3332 << "likeN=" << likeN
3334 << "meanncls=" << meanNcls
3341 //____________________________________________________________________
3342 void AliTRDtrackerV1::GetSeedingConfig(Int_t iconfig, Int_t planes[4])
3345 // Map seeding configurations to detector planes.
3348 // iconfig : configuration index
3349 // planes : member planes of this configuration. On input empty.
3352 // planes : contains the planes which are defining the configuration
3354 // Detailed description
3356 // Here is the list of seeding planes configurations together with
3357 // their topological classification:
3375 // The topologic quality is modeled as follows:
3376 // 1. The general model is define by the equation:
3377 // p(conf) = exp(-conf/2)
3378 // 2. According to the topologic classification, configurations from the same
3379 // class are assigned the agerage value over the model values.
3380 // 3. Quality values are normalized.
3382 // The topologic quality distribution as function of configuration is given below:
3384 // <img src="gif/topologicQA.gif">
3389 case 0: // 5432 TQ 0
3395 case 1: // 4321 TQ 0
3401 case 2: // 3210 TQ 0
3407 case 3: // 5321 TQ 1
3413 case 4: // 4210 TQ 1
3419 case 5: // 5431 TQ 1
3425 case 6: // 4320 TQ 1
3431 case 7: // 5430 TQ 2
3437 case 8: // 5210 TQ 2
3443 case 9: // 5421 TQ 3
3449 case 10: // 4310 TQ 3
3455 case 11: // 5410 TQ 4
3461 case 12: // 5420 TQ 5
3467 case 13: // 5320 TQ 5
3473 case 14: // 5310 TQ 5
3482 //____________________________________________________________________
3483 void AliTRDtrackerV1::GetExtrapolationConfig(Int_t iconfig, Int_t planes[2])
3486 // Returns the extrapolation planes for a seeding configuration.
3489 // iconfig : configuration index
3490 // planes : planes which are not in this configuration. On input empty.
3493 // planes : contains the planes which are not in the configuration
3495 // Detailed description
3499 case 0: // 5432 TQ 0
3503 case 1: // 4321 TQ 0
3507 case 2: // 3210 TQ 0
3511 case 3: // 5321 TQ 1
3515 case 4: // 4210 TQ 1
3519 case 5: // 5431 TQ 1
3523 case 6: // 4320 TQ 1
3527 case 7: // 5430 TQ 2
3531 case 8: // 5210 TQ 2
3535 case 9: // 5421 TQ 3
3539 case 10: // 4310 TQ 3
3543 case 11: // 5410 TQ 4
3547 case 12: // 5420 TQ 5
3551 case 13: // 5320 TQ 5
3555 case 14: // 5310 TQ 5
3562 //____________________________________________________________________
3563 AliCluster* AliTRDtrackerV1::GetCluster(Int_t idx) const
3565 if(!fClusters) return NULL;
3566 Int_t ncls = fClusters->GetEntriesFast();
3567 return idx >= 0 && idx < ncls ? (AliCluster*)fClusters->UncheckedAt(idx) : NULL;
3570 //____________________________________________________________________
3571 AliTRDseedV1* AliTRDtrackerV1::GetTracklet(Int_t idx) const
3573 if(!fTracklets) return NULL;
3574 Int_t ntrklt = fTracklets->GetEntriesFast();
3575 return idx >= 0 && idx < ntrklt ? (AliTRDseedV1*)fTracklets->UncheckedAt(idx) : NULL;
3578 //____________________________________________________________________
3579 AliKalmanTrack* AliTRDtrackerV1::GetTrack(Int_t idx) const
3581 if(!fTracks) return NULL;
3582 Int_t ntrk = fTracks->GetEntriesFast();
3583 return idx >= 0 && idx < ntrk ? (AliKalmanTrack*)fTracks->UncheckedAt(idx) : NULL;
3588 // //_____________________________________________________________________________
3589 // Int_t AliTRDtrackerV1::Freq(Int_t n, const Int_t *inlist
3590 // , Int_t *outlist, Bool_t down)
3593 // // Sort eleements according occurancy
3594 // // The size of output array has is 2*n
3601 // Int_t *sindexS = new Int_t[n]; // Temporary array for sorting
3602 // Int_t *sindexF = new Int_t[2*n];
3603 // for (Int_t i = 0; i < n; i++) {
3607 // TMath::Sort(n,inlist,sindexS,down);
3609 // Int_t last = inlist[sindexS[0]];
3610 // Int_t val = last;
3612 // sindexF[0+n] = last;
3613 // Int_t countPos = 0;
3615 // // Find frequency
3616 // for (Int_t i = 1; i < n; i++) {
3617 // val = inlist[sindexS[i]];
3618 // if (last == val) {
3619 // sindexF[countPos]++;
3623 // sindexF[countPos+n] = val;
3624 // sindexF[countPos]++;
3628 // if (last == val) {
3632 // // Sort according frequency
3633 // TMath::Sort(countPos,sindexF,sindexS,kTRUE);
3635 // for (Int_t i = 0; i < countPos; i++) {
3636 // outlist[2*i ] = sindexF[sindexS[i]+n];
3637 // outlist[2*i+1] = sindexF[sindexS[i]];
3640 // delete [] sindexS;
3641 // delete [] sindexF;
3648 //____________________________________________________________________
3649 void AliTRDtrackerV1::ResetSeedTB()
3651 // reset buffer for seeding time bin layers. If the time bin
3652 // layers are not allocated this function allocates them
3654 for(Int_t isl=0; isl<kNSeedPlanes; isl++){
3655 if(!fSeedTB[isl]) fSeedTB[isl] = new AliTRDchamberTimeBin();
3656 else fSeedTB[isl]->Clear();
3661 //_____________________________________________________________________________
3662 Float_t AliTRDtrackerV1::GetChi2Y(const AliTRDseedV1 * const tracklets) const
3664 // Calculates normalized chi2 in y-direction
3665 // chi2 = Sum chi2 / n_tracklets
3667 Double_t chi2 = 0.; Int_t n = 0;
3668 for(Int_t ipl = kNPlanes; ipl--;){
3669 if(!tracklets[ipl].IsOK()) continue;
3670 chi2 += tracklets[ipl].GetChi2Y();
3673 return n ? chi2/n : 0.;
3676 //_____________________________________________________________________________
3677 Float_t AliTRDtrackerV1::GetChi2Z(const AliTRDseedV1 *const tracklets) const
3679 // Calculates normalized chi2 in z-direction
3680 // chi2 = Sum chi2 / n_tracklets
3682 Double_t chi2 = 0; Int_t n = 0;
3683 for(Int_t ipl = kNPlanes; ipl--;){
3684 if(!tracklets[ipl].IsOK()) continue;
3685 chi2 += tracklets[ipl].GetChi2Z();
3688 return n ? chi2/n : 0.;
3691 //_____________________________________________________________________________
3692 Float_t AliTRDtrackerV1::GetChi2Phi(const AliTRDseedV1 *const tracklets) const
3694 // Calculates normalized chi2 for angular resolution
3695 // chi2 = Sum chi2 / n_tracklets
3697 Double_t chi2 = 0; Int_t n = 0;
3698 for (Int_t iLayer = 0; iLayer < kNPlanes; iLayer++) {
3699 if(!tracklets[iLayer].IsOK()) continue;
3700 chi2 += tracklets[iLayer].GetChi2Phi();
3703 return n ? chi2/n: 0.;
3706 //____________________________________________________________________
3707 Float_t AliTRDtrackerV1::CalculateReferenceX(const AliTRDseedV1 *const tracklets){
3709 // Calculates the reference x-position for the tilted Rieman fit defined as middle
3710 // of the stack (middle between layers 2 and 3). For the calculation all the tracklets
3711 // are taken into account
3713 // Parameters: - Array of tracklets(AliTRDseedV1)
3715 // Output: - The reference x-position(Float_t)
3716 // Only kept for compatibility with the old code
3718 Int_t nDistances = 0;
3719 Float_t meanDistance = 0.;
3720 Int_t startIndex = 5;
3721 for(Int_t il =5; il > 0; il--){
3722 if(tracklets[il].IsOK() && tracklets[il -1].IsOK()){
3723 Float_t xdiff = tracklets[il].GetX0() - tracklets[il -1].GetX0();
3724 meanDistance += xdiff;
3727 if(tracklets[il].IsOK()) startIndex = il;
3729 if(tracklets[0].IsOK()) startIndex = 0;
3731 // We should normally never get here
3732 Float_t xpos[2]; memset(xpos, 0, sizeof(Float_t) * 2);
3733 Int_t iok = 0, idiff = 0;
3734 // This attempt is worse and should be avoided:
3735 // check for two chambers which are OK and repeat this without taking the mean value
3736 // Strategy avoids a division by 0;
3737 for(Int_t il = 5; il >= 0; il--){
3738 if(tracklets[il].IsOK()){
3739 xpos[iok] = tracklets[il].GetX0();
3743 if(iok) idiff++; // to get the right difference;
3747 meanDistance = (xpos[0] - xpos[1])/idiff;
3750 // we have do not even have 2 layers which are OK? The we do not need to fit at all
3755 meanDistance /= nDistances;
3757 return tracklets[startIndex].GetX0() + (2.5 - startIndex) * meanDistance - 0.5 * (AliTRDgeometry::AmThick() + AliTRDgeometry::DrThick());
3760 //_____________________________________________________________________________
3761 Double_t AliTRDtrackerV1::FitTiltedRiemanV1(AliTRDseedV1 *const tracklets){
3763 // Track Fitter Function using the new class implementation of
3766 AliTRDtrackFitterRieman fitter;
3767 fitter.SetRiemanFitter(GetTiltedRiemanFitter());
3769 for(Int_t il = 0; il < AliTRDgeometry::kNlayer; il++) fitter.SetTracklet(il, &tracklets[il]);
3770 Double_t chi2 = fitter.Eval();
3771 // Update the tracklets
3772 Double_t cov[15]; Double_t x0;
3773 memset(cov, 0, sizeof(Double_t) * 15);
3774 for(Int_t il = 0; il < AliTRDgeometry::kNlayer; il++){
3775 x0 = tracklets[il].GetX0();
3776 tracklets[il].SetYref(0, fitter.GetYat(x0));
3777 tracklets[il].SetZref(0, fitter.GetZat(x0));
3778 tracklets[il].SetYref(1, fitter.GetDyDxAt(x0));
3779 tracklets[il].SetZref(1, fitter.GetDzDx());
3780 tracklets[il].SetC(fitter.GetCurvature());
3781 fitter.GetCovAt(x0, cov);
3782 tracklets[il].SetCovRef(cov);
3783 tracklets[il].SetChi2(chi2);
3788 //____________________________________________________________________
3789 void AliTRDtrackerV1::UnsetTrackletsTrack(const AliTRDtrackV1 * const track)
3791 // Remove tracklets from tracker list attached to "track"
3793 for(Int_t il(0); il<kNPlanes; il++){
3794 if((idx = track->GetTrackletIndex(il)) < 0) continue;
3795 delete (fTracklets->RemoveAt(idx));
3800 ///////////////////////////////////////////////////////
3802 // Resources of class AliTRDLeastSquare //
3804 ///////////////////////////////////////////////////////
3806 //_____________________________________________________________________________
3807 AliTRDtrackerV1::AliTRDLeastSquare::AliTRDLeastSquare(){
3809 // Constructor of the nested class AliTRDtrackFitterLeastSquare
3811 // Fast solving linear regresion in 2D
3813 // The data members have the following meaning
3824 // fCovarianceMatrix[0] : s2a
3825 // fCovarianceMatrix[1] : s2b
3826 // fCovarianceMatrix[2] : cov(ab)
3828 memset(fParams, 0, sizeof(Double_t) * 2);
3829 memset(fSums, 0, sizeof(Double_t) * 6);
3830 memset(fCovarianceMatrix, 0, sizeof(Double_t) * 3);
3834 //_____________________________________________________________________________
3835 void AliTRDtrackerV1::AliTRDLeastSquare::AddPoint(const Double_t *const x, Double_t y, Double_t sigmaY){
3837 // Adding Point to the fitter
3840 Double_t weight = 1/(sigmaY > 1e-9 ? sigmaY : 1e-9);
3842 const Double_t &xpt = *x;
3843 // printf("Adding point x = %f, y = %f, sigma = %f\n", xpt, y, sigmaY);
3845 fSums[1] += weight * xpt;
3846 fSums[2] += weight * y;
3847 fSums[3] += weight * xpt * y;
3848 fSums[4] += weight * xpt * xpt;
3849 fSums[5] += weight * y * y;
3852 //_____________________________________________________________________________
3853 void AliTRDtrackerV1::AliTRDLeastSquare::RemovePoint(const Double_t *const x, Double_t y, Double_t sigmaY){
3855 // Remove Point from the sample
3858 Double_t weight = 1/(sigmaY > 1e-9 ? sigmaY : 1e-9);
3860 const Double_t &xpt = *x;
3862 fSums[1] -= weight * xpt;
3863 fSums[2] -= weight * y;
3864 fSums[3] -= weight * xpt * y;
3865 fSums[4] -= weight * xpt * xpt;
3866 fSums[5] -= weight * y * y;
3869 //_____________________________________________________________________________
3870 Bool_t AliTRDtrackerV1::AliTRDLeastSquare::Eval(){
3872 // Evaluation of the fit:
3873 // Calculation of the parameters
3874 // Calculation of the covariance matrix
3877 Double_t det = fSums[0] * fSums[4] - fSums[1] *fSums[1];
3878 if(TMath::Abs(det)<1.e-30) return kFALSE;
3880 // for(Int_t isum = 0; isum < 5; isum++)
3881 // printf("fSums[%d] = %f\n", isum, fSums[isum]);
3882 // printf("denominator = %f\n", denominator);
3883 fParams[0] = (fSums[2] * fSums[4] - fSums[1] * fSums[3])/det;
3884 fParams[1] = (fSums[0] * fSums[3] - fSums[1] * fSums[2])/det;
3885 // printf("fParams[0] = %f, fParams[1] = %f\n", fParams[0], fParams[1]);
3887 // Covariance matrix
3888 Double_t den = fSums[0]*fSums[4] - fSums[1]*fSums[1];
3889 fCovarianceMatrix[0] = fSums[4] / den;
3890 fCovarianceMatrix[1] = fSums[0] / den;
3891 fCovarianceMatrix[2] = -fSums[1] / den;
3892 /* fCovarianceMatrix[0] = fSums[4] / fSums[0] - fSums[1] * fSums[1] / (fSums[0] * fSums[0]);
3893 fCovarianceMatrix[1] = fSums[5] / fSums[0] - fSums[2] * fSums[2] / (fSums[0] * fSums[0]);
3894 fCovarianceMatrix[2] = fSums[3] / fSums[0] - fSums[1] * fSums[2] / (fSums[0] * fSums[0]);*/
3901 //_____________________________________________________________________________
3902 Double_t AliTRDtrackerV1::AliTRDLeastSquare::GetFunctionValue(const Double_t *const xpos) const {
3904 // Returns the Function value of the fitted function at a given x-position
3906 return fParams[0] + fParams[1] * (*xpos);
3909 //_____________________________________________________________________________
3910 void AliTRDtrackerV1::AliTRDLeastSquare::GetCovarianceMatrix(Double_t *storage) const {
3912 // Copies the values of the covariance matrix into the storage
3914 memcpy(storage, fCovarianceMatrix, sizeof(Double_t) * 3);
3917 //_____________________________________________________________________________
3918 void AliTRDtrackerV1::AliTRDLeastSquare::Reset(){
3922 memset(fParams, 0, sizeof(Double_t) * 2);
3923 memset(fCovarianceMatrix, 0, sizeof(Double_t) * 3);
3924 memset(fSums, 0, sizeof(Double_t) * 6);
3927 ///////////////////////////////////////////////////////
3929 // Resources of class AliTRDtrackFitterRieman //
3931 ///////////////////////////////////////////////////////
3933 //_____________________________________________________________________________
3934 AliTRDtrackerV1::AliTRDtrackFitterRieman::AliTRDtrackFitterRieman():
3940 fSysClusterError(0.)
3943 // Default constructor
3945 fZfitter = new AliTRDLeastSquare;
3946 fCovarPolY = new TMatrixD(3,3);
3947 fCovarPolZ = new TMatrixD(2,2);
3948 memset(fTracklets, 0, sizeof(AliTRDseedV1 *) * 6);
3949 memset(fParameters, 0, sizeof(Double_t) * 5);
3950 memset(fSumPolY, 0, sizeof(Double_t) * 5);
3951 memset(fSumPolZ, 0, sizeof(Double_t) * 2);
3954 //_____________________________________________________________________________
3955 AliTRDtrackerV1::AliTRDtrackFitterRieman::~AliTRDtrackFitterRieman(){
3959 if(fZfitter) delete fZfitter;
3960 if(fCovarPolY) delete fCovarPolY;
3961 if(fCovarPolZ) delete fCovarPolZ;
3964 //_____________________________________________________________________________
3965 void AliTRDtrackerV1::AliTRDtrackFitterRieman::Reset(){
3970 fTrackFitter->StoreData(kTRUE);
3971 fTrackFitter->ClearPoints();
3977 memset(fTracklets, 0, sizeof(AliTRDseedV1 *) * AliTRDgeometry::kNlayer);
3978 memset(fParameters, 0, sizeof(Double_t) * 5);
3979 memset(fSumPolY, 0, sizeof(Double_t) * 5);
3980 memset(fSumPolZ, 0, sizeof(Double_t) * 2);
3981 for(Int_t irow = 0; irow < fCovarPolY->GetNrows(); irow++)
3982 for(Int_t icol = 0; icol < fCovarPolY->GetNcols(); icol++){
3983 (*fCovarPolY)(irow, icol) = 0.;
3984 if(irow < 2 && icol < 2)
3985 (*fCovarPolZ)(irow, icol) = 0.;
3989 //_____________________________________________________________________________
3990 void AliTRDtrackerV1::AliTRDtrackFitterRieman::SetTracklet(Int_t itr, AliTRDseedV1 *tracklet){
3992 // Add tracklet into the fitter
3994 if(itr >= AliTRDgeometry::kNlayer) return;
3995 fTracklets[itr] = tracklet;
3998 //_____________________________________________________________________________
3999 Double_t AliTRDtrackerV1::AliTRDtrackFitterRieman::Eval(){
4002 // 1. Apply linear transformation and store points in the fitter
4003 // 2. Evaluate the fit
4004 // 3. Check if the result of the fit in z-direction is reasonable
4006 // 3a. Fix the parameters 3 and 4 with the results of a simple least
4008 // 3b. Redo the fit with the fixed parameters
4009 // 4. Store fit results (parameters and errors)
4014 fXref = CalculateReferenceX();
4015 for(Int_t il = 0; il < AliTRDgeometry::kNlayer; il++) UpdateFitters(fTracklets[il]);
4016 if(!fTrackFitter->GetNpoints()) return 1e10;
4018 fTrackFitter->Eval();
4020 fParameters[3] = fTrackFitter->GetParameter(3);
4021 fParameters[4] = fTrackFitter->GetParameter(4);
4022 if(!CheckAcceptable(fParameters[3], fParameters[4])) {
4023 fTrackFitter->FixParameter(3, fZfitter->GetFunctionValue(&fXref));
4024 fTrackFitter->FixParameter(4, fZfitter->GetFunctionParameter(1));
4025 fTrackFitter->Eval();
4026 fTrackFitter->ReleaseParameter(3);
4027 fTrackFitter->ReleaseParameter(4);
4028 fParameters[3] = fTrackFitter->GetParameter(3);
4029 fParameters[4] = fTrackFitter->GetParameter(4);
4031 // Update the Fit Parameters and the errors
4032 fParameters[0] = fTrackFitter->GetParameter(0);
4033 fParameters[1] = fTrackFitter->GetParameter(1);
4034 fParameters[2] = fTrackFitter->GetParameter(2);
4036 // Prepare Covariance estimation
4037 (*fCovarPolY)(0,0) = fSumPolY[0]; (*fCovarPolY)(1,1) = fSumPolY[2]; (*fCovarPolY)(2,2) = fSumPolY[4];
4038 (*fCovarPolY)(1,0) = (*fCovarPolY)(0,1) = fSumPolY[1];
4039 (*fCovarPolY)(2,0) = (*fCovarPolY)(0,2) = fSumPolY[2];
4040 (*fCovarPolY)(2,1) = (*fCovarPolY)(1,2) = fSumPolY[3];
4041 fCovarPolY->Invert();
4042 (*fCovarPolZ)(0,0) = fSumPolZ[0]; (*fCovarPolZ)(1,1) = fSumPolZ[2];
4043 (*fCovarPolZ)(1,0) = (*fCovarPolZ)(0,1) = fSumPolZ[1];
4044 fCovarPolZ->Invert();
4045 return fTrackFitter->GetChisquare() / fTrackFitter->GetNpoints();
4048 //_____________________________________________________________________________
4049 void AliTRDtrackerV1::AliTRDtrackFitterRieman::UpdateFitters(AliTRDseedV1 * const tracklet){
4051 // Does the transformations and updates the fitters
4052 // The following transformation is applied
4054 AliTRDcluster *cl = NULL;
4055 Double_t x, y, z, dx, t, w, we, yerr, zerr;
4057 if(!tracklet || !tracklet->IsOK()) return;
4058 Double_t tilt = tracklet->GetTilt();
4059 for(Int_t itb = 0; itb < AliTRDseedV1::kNclusters; itb++){
4060 if(!(cl = tracklet->GetClusters(itb))) continue;
4061 if(!cl->IsInChamber()) continue;
4062 if (!tracklet->IsUsable(itb)) continue;
4069 uvt[0] = 2. * x * t;
4071 uvt[2] = 2. * tilt * t;
4072 uvt[3] = 2. * tilt * dx * t;
4073 w = 2. * (y + tilt*z) * t;
4074 // error definition changes for the different calls
4076 we *= TMath::Sqrt(cl->GetSigmaY2()+tilt*tilt*cl->GetSigmaZ2());
4077 // Update sums for error calculation
4078 yerr = 1./(TMath::Sqrt(cl->GetSigmaY2()) + fSysClusterError);
4080 zerr = 1./cl->GetSigmaZ2();
4081 for(Int_t ipol = 0; ipol < 5; ipol++){
4082 fSumPolY[ipol] += yerr;
4085 fSumPolZ[ipol] += zerr;
4089 fTrackFitter->AddPoint(uvt, w, we);
4090 fZfitter->AddPoint(&x, z, static_cast<Double_t>(TMath::Sqrt(cl->GetSigmaZ2())));
4094 //_____________________________________________________________________________
4095 Bool_t AliTRDtrackerV1::AliTRDtrackFitterRieman::CheckAcceptable(Double_t offset, Double_t slope){
4097 // Check whether z-results are acceptable
4098 // Definition: Distance between tracklet fit and track fit has to be
4099 // less then half a padlength
4100 // Point of comparision is at the anode wire
4102 Bool_t acceptablez = kTRUE;
4103 Double_t zref = 0.0;
4104 for (Int_t iLayer = 0; iLayer < kNPlanes; iLayer++) {
4105 if(!fTracklets[iLayer]->IsOK()) continue;
4106 zref = offset + slope * (fTracklets[iLayer]->GetX0() - fXref);
4107 if (TMath::Abs(fTracklets[iLayer]->GetZfit(0) - zref) > fTracklets[iLayer]->GetPadLength() * 0.5 + 1.0)
4108 acceptablez = kFALSE;
4113 //_____________________________________________________________________________
4114 Double_t AliTRDtrackerV1::AliTRDtrackFitterRieman::GetYat(Double_t x) const {
4116 // Calculate y position out of the track parameters
4117 // y: R^2 = (x - x0)^2 + (y - y0)^2
4118 // => y = y0 +/- Sqrt(R^2 - (x - x0)^2)
4119 // R = Sqrt() = 1/Curvature
4120 // => y = y0 +/- Sqrt(1/Curvature^2 - (x - x0)^2)
4123 Double_t disc = (x * fParameters[0] + fParameters[1]);
4124 disc = 1 - fParameters[0]*fParameters[2] + fParameters[1]*fParameters[1] - disc*disc;
4126 disc = TMath::Sqrt(disc);
4127 y = (1.0 - disc) / fParameters[0];
4132 //_____________________________________________________________________________
4133 Double_t AliTRDtrackerV1::AliTRDtrackFitterRieman::GetZat(Double_t x) const {
4135 // Return z position for a given x position
4136 // Simple linear function
4138 return fParameters[3] + fParameters[4] * (x - fXref);
4141 //_____________________________________________________________________________
4142 Double_t AliTRDtrackerV1::AliTRDtrackFitterRieman::GetDyDxAt(Double_t x) const {
4144 // Calculate dydx at a given radial position out of the track parameters
4145 // dy: R^2 = (x - x0)^2 + (y - y0)^2
4146 // => y = +/- Sqrt(R^2 - (x - x0)^2) + y0
4147 // => dy/dx = (x - x0)/Sqrt(R^2 - (x - x0)^2)
4148 // Curvature: cr = 1/R = a/Sqrt(1 + b^2 - c*a)
4149 // => dy/dx = (x - x0)/(1/(cr^2) - (x - x0)^2)
4151 Double_t x0 = -fParameters[1] / fParameters[0];
4152 Double_t curvature = GetCurvature();
4154 if (-fParameters[2] * fParameters[0] + fParameters[1] * fParameters[1] + 1 > 0) {
4155 if (1.0/(curvature * curvature) - (x - x0) * (x - x0) > 0.0) {
4156 Double_t yderiv = (x - x0) / TMath::Sqrt(1.0/(curvature * curvature) - (x - x0) * (x - x0));
4157 if (fParameters[0] < 0) yderiv *= -1.0;
4164 //_____________________________________________________________________________
4165 Double_t AliTRDtrackerV1::AliTRDtrackFitterRieman::GetCurvature() const {
4167 // Calculate track curvature
4170 Double_t curvature = 1.0 + fParameters[1]*fParameters[1] - fParameters[2]*fParameters[0];
4171 if (curvature > 0.0)
4172 curvature = fParameters[0] / TMath::Sqrt(curvature);
4176 //_____________________________________________________________________________
4177 void AliTRDtrackerV1::AliTRDtrackFitterRieman::GetCovAt(Double_t x, Double_t *cov) const {
4179 // Error Definition according to gauss error propagation
4181 TMatrixD transform(3,3);
4182 transform(0,0) = transform(1,1) = transform(2,2) = 1;
4183 transform(0,1) = transform(1,2) = x;
4184 transform(0,2) = x*x;
4185 TMatrixD covariance(transform, TMatrixD::kMult, *fCovarPolY);
4186 covariance *= transform.T();
4187 cov[0] = covariance(0,0);
4188 TMatrixD transformZ(2,2);
4189 transformZ(0,0) = transformZ(1,1) = 1;
4190 transformZ(0,1) = x;
4191 TMatrixD covarZ(transformZ, TMatrixD::kMult, *fCovarPolZ);
4192 covarZ *= transformZ.T();
4193 cov[1] = covarZ(0,0);
4197 //____________________________________________________________________
4198 Double_t AliTRDtrackerV1::AliTRDtrackFitterRieman::CalculateReferenceX(){
4200 // Calculates the reference x-position for the tilted Rieman fit defined as middle
4201 // of the stack (middle between layers 2 and 3). For the calculation all the tracklets
4202 // are taken into account
4204 // Parameters: - Array of tracklets(AliTRDseedV1)
4206 // Output: - The reference x-position(Float_t)
4208 Int_t nDistances = 0;
4209 Float_t meanDistance = 0.;
4210 Int_t startIndex = 5;
4211 for(Int_t il =5; il > 0; il--){
4212 if(fTracklets[il]->IsOK() && fTracklets[il -1]->IsOK()){
4213 Float_t xdiff = fTracklets[il]->GetX0() - fTracklets[il -1]->GetX0();
4214 meanDistance += xdiff;
4217 if(fTracklets[il]->IsOK()) startIndex = il;
4219 if(fTracklets[0]->IsOK()) startIndex = 0;
4221 // We should normally never get here
4222 Float_t xpos[2]; memset(xpos, 0, sizeof(Float_t) * 2);
4223 Int_t iok = 0, idiff = 0;
4224 // This attempt is worse and should be avoided:
4225 // check for two chambers which are OK and repeat this without taking the mean value
4226 // Strategy avoids a division by 0;
4227 for(Int_t il = 5; il >= 0; il--){
4228 if(fTracklets[il]->IsOK()){
4229 xpos[iok] = fTracklets[il]->GetX0();
4233 if(iok) idiff++; // to get the right difference;
4237 meanDistance = (xpos[0] - xpos[1])/idiff;
4240 // we have do not even have 2 layers which are OK? The we do not need to fit at all
4245 meanDistance /= nDistances;
4247 return fTracklets[startIndex]->GetX0() + (2.5 - startIndex) * meanDistance - 0.5 * (AliTRDgeometry::AmThick() + AliTRDgeometry::DrThick());