#include <TTree.h>
#include <TClonesArray.h>
#include <TTreeStream.h>
+#include <TGeoMatrix.h>
+#include <TGeoManager.h>
#include "AliLog.h"
#include "AliMathBase.h"
const Double_t AliTRDtrackerV1::fgkMaxSnp = 0.95; // Maximum local sine of the azimuthal angle
const Double_t AliTRDtrackerV1::fgkMaxStep = 2.0; // Maximal step size in propagation
Double_t AliTRDtrackerV1::fgTopologicQA[kNConfigs] = {
- 0.1112, 0.1112, 0.1112, 0.0786, 0.0786,
+ 0.5112, 0.5112, 0.5112, 0.0786, 0.0786,
0.0786, 0.0786, 0.0579, 0.0579, 0.0474,
0.0474, 0.0408, 0.0335, 0.0335, 0.0335
-};
+};
+const Double_t AliTRDtrackerV1::fgkX0[kNPlanes] = {
+ 300.2, 312.8, 325.4, 338.0, 350.6, 363.2};
Int_t AliTRDtrackerV1::fgNTimeBins = 0;
AliRieman* AliTRDtrackerV1::fgRieman = 0x0;
TLinearFitter* AliTRDtrackerV1::fgTiltedRieman = 0x0;
AliTRDtrackerV1::AliTRDtrackerV1(AliTRDReconstructor *rec)
:AliTracker()
,fReconstructor(0x0)
- ,fGeom(new AliTRDgeometry())
+ ,fGeom(0x0)
,fClusters(0x0)
,fTracklets(0x0)
,fTracks(0x0)
//
// Default constructor.
//
+
+ SetReconstructor(rec); // initialize reconstructor
+
+ // initialize geometry
+ if(!AliGeomManager::GetGeometry()){
+ AliFatal("Could not get geometry.");
+ }
+ fGeom = new AliTRDgeometry();
+ fGeom->CreateClusterMatrixArray();
+ TGeoHMatrix *matrix = 0x0;
+ Double_t loc[] = {0., 0., 0.};
+ Double_t glb[] = {0., 0., 0.};
+ for(Int_t ily=kNPlanes; ily--;){
+ Int_t ism = 0;
+ while(!(matrix = fGeom->GetClusterMatrix(AliTRDgeometry::GetDetector(ily, 2, ism)))) ism++;
+ if(!matrix){
+ AliError(Form("Could not get transformation matrix for layer %d. Use default.", ily));
+ fR[ily] = fgkX0[ily];
+ continue;
+ }
+ matrix->LocalToMaster(loc, glb);
+ fR[ily] = glb[0]+ AliTRDgeometry::AnodePos()-.5*AliTRDgeometry::AmThick() - AliTRDgeometry::DrThick();
+ }
+
+ // initialize calibration values
AliTRDcalibDB *trd = 0x0;
if (!(trd = AliTRDcalibDB::Instance())) {
- AliFatal("Could not get calibration object");
+ AliFatal("Could not get calibration.");
}
-
if(!fgNTimeBins) fgNTimeBins = trd->GetNumberOfTimeBins();
+ // initialize cluster containers
for (Int_t isector = 0; isector < AliTRDgeometry::kNsector; isector++) new(&fTrSec[isector]) AliTRDtrackingSector(fGeom, isector);
- for(Int_t isl =0; isl<kNSeedPlanes; isl++) fSeedTB[isl] = 0x0;
-
- // Initialize debug stream
- if(rec) SetReconstructor(rec);
+ // initialize arrays
+ memset(fTrackQuality, 0, kMaxTracksStack*sizeof(Double_t));
+ memset(fSeedLayer, 0, kMaxTracksStack*sizeof(Int_t));
+ memset(fSeedTB, 0, kNSeedPlanes*sizeof(AliTRDchamberTimeBin*));
}
//____________________________________________________________________
if (!tracklet) return kFALSE;
// get detector for this tracklet
- Int_t idet = tracklet->GetDetector();
-
+ Int_t det = tracklet->GetDetector();
+ Int_t sec = fGeom->GetSector(det);
+ Double_t alpha = (sec+.5)*AliTRDgeometry::GetAlpha(),
+ sinA = TMath::Sin(alpha),
+ cosA = TMath::Cos(alpha);
Double_t local[3];
- local[0] = tracklet->GetX0();
- local[1] = tracklet->GetYfit(0);
- local[2] = tracklet->GetZfit(0);
+ local[0] = tracklet->GetX();
+ local[1] = tracklet->GetY();
+ local[2] = tracklet->GetZ();
Double_t global[3];
- fGeom->RotateBack(idet, local, global);
- p.SetXYZ(global[0],global[1],global[2]);
-
+ fGeom->RotateBack(det, local, global);
+
+ Double_t cov2D[3]; Float_t cov[6];
+ tracklet->GetCovAt(local[0], cov2D);
+ cov[0] = cov2D[0]*sinA*sinA;
+ cov[1] =-cov2D[0]*sinA*cosA;
+ cov[2] =-cov2D[1]*sinA;
+ cov[3] = cov2D[0]*cosA*cosA;
+ cov[4] = cov2D[1]*cosA;
+ cov[5] = cov2D[2];
+ // store the global position of the tracklet and its covariance matrix in the track point
+ p.SetXYZ(global[0],global[1],global[2], cov);
// setting volume id
- AliGeomManager::ELayerID iLayer = AliGeomManager::kTRD1;
- switch (fGeom->GetLayer(idet)) {
- case 0:
- iLayer = AliGeomManager::kTRD1;
- break;
- case 1:
- iLayer = AliGeomManager::kTRD2;
- break;
- case 2:
- iLayer = AliGeomManager::kTRD3;
- break;
- case 3:
- iLayer = AliGeomManager::kTRD4;
- break;
- case 4:
- iLayer = AliGeomManager::kTRD5;
- break;
- case 5:
- iLayer = AliGeomManager::kTRD6;
- break;
- };
- Int_t modId = fGeom->GetSector(idet) * fGeom->Nstack() + fGeom->GetStack(idet);
+ AliGeomManager::ELayerID iLayer = AliGeomManager::ELayerID(AliGeomManager::kTRD1+fGeom->GetLayer(det));
+ Int_t modId = fGeom->GetSector(det) * AliTRDgeometry::kNstack + fGeom->GetStack(det);
UShort_t volid = AliGeomManager::LayerToVolUID(iLayer, modId);
p.SetVolumeID(volid);
//_____________________________________________________________________________
Int_t AliTRDtrackerV1::PropagateBack(AliESDEvent *event)
{
- //
- // Gets seeds from ESD event. The seeds are AliTPCtrack's found and
- // backpropagated by the TPC tracker. Each seed is first propagated
- // to the TRD, and then its prolongation is searched in the TRD.
- // If sufficiently long continuation of the track is found in the TRD
- // the track is updated, otherwise it's stored as originaly defined
- // by the TPC tracker.
- //
-
- // Calibration monitor
- AliTRDCalibraFillHisto *calibra = AliTRDCalibraFillHisto::Instance();
+// Propagation of ESD tracks from TPC to TOF detectors and building of the TRD track. For building
+// a TRD track an ESD track is used as seed. The informations obtained on the TRD track (measured points,
+// covariance, PID, etc.) are than used to update the corresponding ESD track.
+// Each track seed is first propagated to the geometrical limit of the TRD detector.
+// Its prolongation is searched in the TRD and if corresponding clusters are found tracklets are
+// constructed out of them (see AliTRDseedV1::AttachClusters()) and the track is updated.
+// Otherwise the ESD track is left unchanged.
+//
+// The following steps are performed:
+// 1. Selection of tracks based on the variance in the y-z plane.
+// 2. Propagation to the geometrical limit of the TRD volume. If track propagation fails the AliESDtrack::kTRDStop is set.
+// 3. Prolongation inside the fiducial volume (see AliTRDtrackerV1::FollowBackProlongation()) and marking
+// the following status bits:
+// - AliESDtrack::kTRDin - if the tracks enters the TRD fiducial volume
+// - AliESDtrack::kTRDStop - if the tracks fails propagation
+// - AliESDtrack::kTRDbackup - if the tracks fulfills chi2 conditions and qualify for refitting
+// 4. Writting to friends, PID, MC label, quality etc. Setting status bit AliESDtrack::kTRDout.
+// 5. Propagation to TOF. If track propagation fails the AliESDtrack::kTRDStop is set.
+//
+
+ AliTRDCalibraFillHisto *calibra = AliTRDCalibraFillHisto::Instance(); // Calibration monitor
if (!calibra) AliInfo("Could not get Calibra instance\n");
- Int_t found = 0; // number of tracks found
+ // Define scalers
+ Int_t nFound = 0, // number of tracks found
+ nSeeds = 0, // total number of ESD seeds
+ nTRDseeds= 0, // number of seeds in the TRD acceptance
+ nTPCseeds= 0; // number of TPC seeds
Float_t foundMin = 20.0;
Float_t *quality = 0x0;
Int_t *index = 0x0;
- Int_t nSeed = event->GetNumberOfTracks();
- if(nSeed){
- quality = new Float_t[nSeed];
- index = new Int_t[nSeed];
- for (Int_t iSeed = 0; iSeed < nSeed; iSeed++) {
+ nSeeds = event->GetNumberOfTracks();
+ // Sort tracks according to quality
+ // (covariance in the yz plane)
+ if(nSeeds){
+ quality = new Float_t[nSeeds];
+ index = new Int_t[nSeeds];
+ for (Int_t iSeed = nSeeds; iSeed--;) {
AliESDtrack *seed = event->GetTrack(iSeed);
Double_t covariance[15];
seed->GetExternalCovariance(covariance);
quality[iSeed] = covariance[0] + covariance[2];
}
- // Sort tracks according to covariance of local Y and Z
- TMath::Sort(nSeed, quality, index,kFALSE);
+ TMath::Sort(nSeeds, quality, index,kFALSE);
}
- // Backpropagate all seeds
+ // Propagate all seeds
Int_t expectedClr;
AliTRDtrackV1 track;
- for (Int_t iSeed = 0; iSeed < nSeed; iSeed++) {
+ for (Int_t iSeed = 0; iSeed < nSeeds; iSeed++) {
// Get the seeds in sorted sequence
AliESDtrack *seed = event->GetTrack(index[iSeed]);
+ Float_t p4 = seed->GetC(seed->GetBz());
// Check the seed status
ULong_t status = seed->GetStatus();
if ((status & AliESDtrack::kTPCout) == 0) continue;
if ((status & AliESDtrack::kTRDout) != 0) continue;
-
- // Do the back prolongation
+
+ // Propagate to the entrance in the TRD mother volume
new(&track) AliTRDtrackV1(*seed);
- track.SetReconstructor(fReconstructor);
- track.SetKink(Bool_t(seed->GetKinkIndex(0)));
- //Int_t lbl = seed->GetLabel();
- //track.SetSeedLabel(lbl);
+ if(AliTRDgeometry::GetXtrdBeg() > (fgkMaxStep + track.GetX()) && !PropagateToX(track, AliTRDgeometry::GetXtrdBeg(), fgkMaxStep)){
+ seed->UpdateTrackParams(&track, AliESDtrack::kTRDStop);
+ continue;
+ }
+ if(!AdjustSector(&track)){
+ seed->UpdateTrackParams(&track, AliESDtrack::kTRDStop);
+ continue;
+ }
+ if(TMath::Abs(track.GetSnp()) > fgkMaxSnp) {
+ seed->UpdateTrackParams(&track, AliESDtrack::kTRDStop);
+ continue;
+ }
- // Make backup and mark entrance in the TRD
- seed->UpdateTrackParams(&track, AliESDtrack::kTRDin);
+ nTPCseeds++;
+
+ // store track status at TRD entrance
seed->UpdateTrackParams(&track, AliESDtrack::kTRDbackup);
- Float_t p4 = track.GetC(track.GetBz());
- expectedClr = FollowBackProlongation(track);
- if (expectedClr<0) continue; // Back prolongation failed
+ // prepare track and do propagation in the TRD
+ track.SetReconstructor(fReconstructor);
+ track.SetKink(Bool_t(seed->GetKinkIndex(0)));
+ expectedClr = FollowBackProlongation(track);
+ // check if track entered the TRD fiducial volume
+ if(track.GetTrackLow()){
+ seed->UpdateTrackParams(&track, AliESDtrack::kTRDin);
+ nTRDseeds++;
+ }
+ // check if track was stopped in the TRD
+ if (expectedClr<0){
+ seed->UpdateTrackParams(&track, AliESDtrack::kTRDStop);
+ continue;
+ }
if(expectedClr){
- found++;
+ nFound++;
// computes PID for track
track.CookPID();
// update calibration references using this track
if(calibra->GetHisto2d()) calibra->UpdateHistogramsV1(&track);
// save calibration object
- if (fReconstructor->GetStreamLevel(AliTRDReconstructor::kTracker) > 0 /*&& quality TODO*/){
+ if (fReconstructor->GetStreamLevel(AliTRDReconstructor::kTracker) > 0){
AliTRDtrackV1 *calibTrack = new AliTRDtrackV1(track);
calibTrack->SetOwner();
seed->AddCalibObject(calibTrack);
isGold = kTRUE;
}
}
-
- //if ((track->StatusForTOF() > 0) && (track->GetNCross() == 0) && (Float_t(track->GetNumberOfClusters()) / Float_t(track->GetNExpected()) > 0.4)) {
- //seed->UpdateTrackParams(track->GetBackupTrack(), AliESDtrack::kTRDbackup);
- //}
}
}
- // Propagation to the TOF (I.Belikov)
- if (track.IsStopped() == kFALSE) {
- Double_t xtof = 371.0;
- Double_t xTOF0 = 370.0;
-
- Double_t c2 = track.GetSnp() + track.GetC(track.GetBz()) * (xtof - track.GetX());
- if (TMath::Abs(c2) >= 0.99) continue;
-
- if (!PropagateToX(track, xTOF0, fgkMaxStep)) continue;
-
- // Energy losses taken to the account - check one more time
- c2 = track.GetSnp() + track.GetC(track.GetBz()) * (xtof - track.GetX());
- if (TMath::Abs(c2) >= 0.99) continue;
-
- //if (!PropagateToX(*track,xTOF0,fgkMaxStep)) {
- // fHBackfit->Fill(7);
- //delete track;
- // continue;
- //}
-
- Double_t ymax = xtof * TMath::Tan(0.5 * AliTRDgeometry::GetAlpha());
- Double_t y;
- track.GetYAt(xtof,GetBz(),y);
- if (y > ymax) {
- if (!track.Rotate( AliTRDgeometry::GetAlpha())) continue;
- }else if (y < -ymax) {
- if (!track.Rotate(-AliTRDgeometry::GetAlpha())) continue;
+ // Propagation to the TOF
+ if(!(seed->GetStatus()&AliESDtrack::kTRDStop)) {
+ Int_t sm = track.GetSector();
+ // default value in case we have problems with the geometry.
+ Double_t xtof = 371.;
+ //Calculate radial position of the beginning of the TOF
+ //mother volume. In order to avoid mixing of the TRD
+ //and TOF modules some hard values are needed. This are:
+ //1. The path to the TOF module.
+ //2. The width of the TOF (29.05 cm)
+ //(with the help of Annalisa de Caro Mar-17-2009)
+ if(gGeoManager){
+ gGeoManager->cd(Form("/ALIC_1/B077_1/BSEGMO%d_1/BTOF%d_1", sm, sm));
+ TGeoHMatrix *m = 0x0;
+ Double_t loc[]={0., 0., -.5*29.05}, glob[3];
+
+ if((m=gGeoManager->GetCurrentMatrix())){
+ m->LocalToMaster(loc, glob);
+ xtof = TMath::Sqrt(glob[0]*glob[0]+glob[1]*glob[1]);
+ }
}
-
- if (track.PropagateTo(xtof)) {
- seed->UpdateTrackParams(&track, AliESDtrack::kTRDout);
- track.UpdateESDtrack(seed);
+ if(xtof > (fgkMaxStep + track.GetX()) && !PropagateToX(track, xtof, fgkMaxStep)){
+ seed->UpdateTrackParams(&track, AliESDtrack::kTRDStop);
+ continue;
}
- } else {
- if ((track.GetNumberOfClusters() > 15) && (track.GetNumberOfClusters() > 0.5*expectedClr)) {
- seed->UpdateTrackParams(&track, AliESDtrack::kTRDout);
-
- track.UpdateESDtrack(seed);
+ if(!AdjustSector(&track)){
+ seed->UpdateTrackParams(&track, AliESDtrack::kTRDStop);
+ continue;
+ }
+ if(TMath::Abs(track.GetSnp()) > fgkMaxSnp){
+ seed->UpdateTrackParams(&track, AliESDtrack::kTRDStop);
+ continue;
}
+ seed->UpdateTrackParams(&track, AliESDtrack::kTRDout);
+ // TODO obsolete - delete
+ seed->SetTRDQuality(track.StatusForTOF());
}
-
- seed->SetTRDQuality(track.StatusForTOF());
seed->SetTRDBudget(track.GetBudget(0));
}
if(index) delete [] index;
if(quality) delete [] quality;
-
- AliInfo(Form("Number of seeds: %d", nSeed));
- AliInfo(Form("Number of back propagated TRD tracks: %d", found));
-
+ AliInfo(Form("Number of seeds: TPCout[%d] TRDin[%d]", nTPCseeds, nTRDseeds));
+ AliInfo(Form("Number of tracks: TRDout[%d]", nFound));
+
// run stand alone tracking
if (fReconstructor->IsSeeding()) Clusters2Tracks(event);
kStoreIn = kFALSE;
}
- Double_t maxChi2 = t.GetPredictedChi2(tracklet);
- if (maxChi2 < 1e+10 && t.Update(tracklet, maxChi2)){
+ Double_t cov[3]; tracklet->GetCovAt(x, cov);
+ Double_t p[2] = { tracklet->GetY(), tracklet->GetZ()};
+ Double_t chi2 = ((AliExternalTrackParam)t).GetPredictedChi2(p, cov);
+ if (chi2 < 1e+10 && t.Update(p, cov, chi2)){
nClustersExpected += tracklet->GetN();
}
}
Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
TTreeSRedirector &cstreamer = *fReconstructor->GetDebugStream(AliTRDReconstructor::kTracker);
+ AliTRDtrackV1 track(t);
+ track.SetOwner();
cstreamer << "FollowProlongation"
<< "EventNumber=" << eventNumber
<< "ncl=" << nClustersExpected
- //<< "track.=" << &t
+ << "track.=" << &track
<< "\n";
}
//_____________________________________________________________________________
Int_t AliTRDtrackerV1::FollowBackProlongation(AliTRDtrackV1 &t)
{
- // Extrapolates the TRD track in the TOF direction.
- //
- // Parameters
- // t : the TRD track which has to be extrapolated
- //
- // Output
- // number of clusters attached to the track
- //
- // Detailed description
- //
- // Starting from current radial position of track <t> this function
- // extrapolates the track through the 6 TRD layers. The following steps
- // are being performed for each plane:
- // 1. prepare track:
- // a. get plane limits in the local x direction
- // b. check crossing sectors
- // c. check track inclination
- // 2. build tracklet (see AliTRDseed::AttachClusters() for details)
- // 3. evaluate material budget using the geo manager
- // 4. propagate and update track using the tracklet information.
- //
- // Debug level 2
- //
-
- Int_t nClustersExpected = 0;
- Double_t clength = .5*AliTRDgeometry::AmThick() + AliTRDgeometry::DrThick();
+// Extrapolates/Build the TRD track in the TOF direction.
+//
+// Parameters
+// t : the TRD track which has to be extrapolated
+//
+// Output
+// number of clusters attached to the track
+//
+// Starting from current radial position of track <t> this function
+// extrapolates the track through the 6 TRD layers. The following steps
+// are being performed for each plane:
+// 1. Propagate track to the entrance of the next chamber:
+// - get chamber limits in the radial direction
+// - check crossing sectors
+// - check track inclination
+// - check track prolongation against boundary conditions (see exclusion boundaries on AliTRDgeometry::IsOnBoundary())
+// 2. Build tracklet (see AliTRDseed::AttachClusters() for details) for this layer if needed. If only
+// Kalman filter is needed and tracklets are already linked to the track this step is skipped.
+// 3. Fit tracklet using the information from the Kalman filter.
+// 4. Propagate and update track at reference radial position of the tracklet.
+// 5. Register tracklet with the tracker and track; update pulls monitoring.
+//
+// Observation
+// 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:
+// - AliTRDtrackV1::kProlongation : track prolongation failed
+// - AliTRDtrackV1::kPropagation : track prolongation failed
+// - AliTRDtrackV1::kAdjustSector : failed during sector crossing
+// - AliTRDtrackV1::kSnp : too large bending
+// - AliTRDtrackV1::kTrackletInit : fail to initialize tracklet
+// - AliTRDtrackV1::kUpdate : fail to attach clusters or fit the tracklet
+// - AliTRDtrackV1::kUnknown : anything which is not covered before
+// 2. By default the status of the track before first TRD update is saved.
+//
+// Debug level 2
+//
+// Author
+// Alexandru Bercuci <A.Bercuci@gsi.de>
+//
+
+ Int_t n = 0;
+ Double_t driftLength = .5*AliTRDgeometry::AmThick() + AliTRDgeometry::DrThick();
AliTRDtrackingChamber *chamber = 0x0;
AliTRDseedV1 tracklet, *ptrTracklet = 0x0;
tracklets[ip] = t.GetTracklet(ip);
t.UnsetTracklet(ip);
}
- Bool_t kStoreIn = kTRUE;
-
+ Bool_t kStoreIn = kTRUE, kPropagateIn = kTRUE;
// Loop through the TRD layers
- for (Int_t ilayer = 0; ilayer < kNPlanes; ilayer++) {
- // BUILD TRACKLET IF NOT ALREADY BUILT
- Double_t x = 0., x0, y, z, alpha;
- ptrTracklet = tracklets[ilayer];
- if(!ptrTracklet){
- ptrTracklet = new(&tracklet) AliTRDseedV1(ilayer);
- ptrTracklet->SetReconstructor(fReconstructor);
- ptrTracklet->SetKink(t.IsKink());
- alpha = t.GetAlpha();
- Int_t sector = Int_t(alpha/AliTRDgeometry::GetAlpha() + (alpha>0. ? 0 : AliTRDgeometry::kNsector));
+ TGeoHMatrix *matrix = 0x0;
+ Double_t x, y, z;
+ for (Int_t ily=0, sm=-1, stk=-1, det=-1; ily < AliTRDgeometry::kNlayer; ily++) {
+ // rough estimate of the entry point
+ if (!t.GetProlongation(fR[ily], y, z)){
+ n=-1;
+ t.SetStatus(AliTRDtrackV1::kProlongation);
+ break;
+ }
- if(!fTrSec[sector].GetNChambers()) continue;
-
- if((x = fTrSec[sector].GetX(ilayer)) < 1.) continue;
-
- // Propagate closer to the current layer
- x0 = x - 1.5*clength;
- if (x0 > (fgkMaxStep + t.GetX()) && !PropagateToX(t, x0-fgkMaxStep, fgkMaxStep)) return -1/*nClustersExpected*/;
- if (!AdjustSector(&t)) return -1/*nClustersExpected*/;
- if (TMath::Abs(t.GetSnp()) > fgkMaxSnp) return -1/*nClustersExpected*/;
-
- if (!t.GetProlongation(x, y, z)) return -1/*nClustersExpected*/;
- Int_t stack = fGeom->GetStack(z, ilayer);
- Int_t nCandidates = stack >= 0 ? 1 : 2;
- z -= stack >= 0 ? 0. : 4.;
-
- for(int icham=0; icham<nCandidates; icham++, z+=8){
- if((stack = fGeom->GetStack(z, ilayer)) < 0) continue;
-
- if(!(chamber = fTrSec[sector].GetChamber(stack, ilayer))) continue;
-
- if(chamber->GetNClusters() < fgNTimeBins*fReconstructor->GetRecoParam() ->GetFindableClusters()) continue;
-
- x = chamber->GetX();
-
- AliTRDpadPlane *pp = fGeom->GetPadPlane(ilayer, stack);
- tracklet.SetTilt(TMath::Tan(TMath::DegToRad()*pp->GetTiltingAngle()));
- tracklet.SetPadLength(pp->GetLengthIPad());
- tracklet.SetDetector(chamber->GetDetector());
- tracklet.SetX0(x);
- tracklet.UpDate(&t);
-// if(!tracklet.Init(&t)){
-// t.SetStopped(kTRUE);
-// return nClustersExpected;
-// }
- if(!tracklet.AttachClusters(chamber, kTRUE)) continue;
- //if(!tracklet.AttachClustersIter(chamber, 1000.)) continue;
- //tracklet.Init(&t);
-
- if(tracklet.GetN() < fgNTimeBins*fReconstructor->GetRecoParam() ->GetFindableClusters()) continue;
-
+ // find sector / stack / detector
+ sm = t.GetSector();
+ // TODO cross check with y value !
+ stk = fGeom->GetStack(z, ily);
+ det = stk>=0 ? AliTRDgeometry::GetDetector(ily, stk, sm) : -1;
+ matrix = det>=0 ? fGeom->GetClusterMatrix(det) : 0x0;
+
+ // check if supermodule/chamber is installed
+ if( !fGeom->GetSMstatus(sm) ||
+ stk<0. ||
+ fGeom->IsHole(ily, stk, sm) ||
+ !matrix ){
+ // propagate to the default radial position
+ if(fR[ily] > (fgkMaxStep + t.GetX()) && !PropagateToX(t, fR[ily], fgkMaxStep)){
+ n=-1;
+ t.SetStatus(AliTRDtrackV1::kPropagation);
break;
}
- ptrTracklet->UpdateUsed();
- }
- if(!ptrTracklet->IsOK()){
- ptrTracklet->Reset();
- if(x < 1.) continue; //temporary
- if(!PropagateToX(t, x-fgkMaxStep, fgkMaxStep)) return -1/*nClustersExpected*/;
- if(!AdjustSector(&t)) return -1/*nClustersExpected*/;
- if(TMath::Abs(t.GetSnp()) > fgkMaxSnp) return -1/*nClustersExpected*/;
+ if(!AdjustSector(&t)){
+ n=-1;
+ t.SetStatus(AliTRDtrackV1::kAdjustSector);
+ break;
+ }
+ if(TMath::Abs(t.GetSnp()) > fgkMaxSnp){
+ n=-1;
+ t.SetStatus(AliTRDtrackV1::kSnp);
+ break;
+ }
+ t.SetStatus(AliTRDtrackV1::kGeometry, ily);
continue;
}
-
- // Propagate closer to the current chamber if neccessary
- x -= clength;
- if (x > (fgkMaxStep + t.GetX()) && !PropagateToX(t, x-fgkMaxStep, fgkMaxStep)) return -1/*nClustersExpected*/;
- if (!AdjustSector(&t)) return -1/*nClustersExpected*/;
- if (TMath::Abs(t.GetSnp()) > fgkMaxSnp) return -1/*nClustersExpected*/;
-
- // load tracklet to the tracker and the track
- ptrTracklet->UseClusters();
- ptrTracklet->Fit(kFALSE); // no tilt correction
- ptrTracklet = SetTracklet(ptrTracklet);
- t.SetTracklet(ptrTracklet, fTracklets->GetEntriesFast()-1);
-
-
- // Calculate the mean material budget along the path inside the chamber
- //Calculate global entry and exit positions of the track in chamber (only track prolongation)
- Double_t xyz0[3]; // entry point
- t.GetXYZ(xyz0);
- alpha = t.GetAlpha();
- x = ptrTracklet->GetX(); //GetX0();
- if (!t.GetProlongation(x, y, z)) return -1/*nClustersExpected*/;
- Double_t xyz1[3]; // exit point
- xyz1[0] = x * TMath::Cos(alpha) - y * TMath::Sin(alpha);
- xyz1[1] = +x * TMath::Sin(alpha) + y * TMath::Cos(alpha);
- xyz1[2] = z;
- Double_t param[7];
- if(AliTracker::MeanMaterialBudget(xyz0, xyz1, param)<=0.) return -1;
- // The mean propagation parameters
- Double_t xrho = param[0]*param[4]; // density*length
- Double_t xx0 = param[1]; // radiation length
-
- // Propagate and update track
- if (!t.PropagateTo(x, xx0, xrho)) return -1/*nClustersExpected*/;
- if (!AdjustSector(&t)) return -1/*nClustersExpected*/;
+ // retrieve rotation matrix for the current chamber
+ Double_t loc[] = {AliTRDgeometry::AnodePos()- driftLength, 0., 0.};
+ Double_t glb[] = {0., 0., 0.};
+ matrix->LocalToMaster(loc, glb);
+
+ // Propagate to the radial distance of the current layer
+ x = glb[0] - fgkMaxStep;
+ if(x > (fgkMaxStep + t.GetX()) && !PropagateToX(t, x, fgkMaxStep)){
+ n=-1;
+ t.SetStatus(AliTRDtrackV1::kPropagation);
+ break;
+ }
+ if(!AdjustSector(&t)){
+ n=-1;
+ t.SetStatus(AliTRDtrackV1::kAdjustSector);
+ break;
+ }
+ if(TMath::Abs(t.GetSnp()) > fgkMaxSnp) {
+ n=-1;
+ t.SetStatus(AliTRDtrackV1::kSnp);
+ break;
+ }
+ Bool_t RECALCULATE = kFALSE;
+ if(sm != t.GetSector()){
+ sm = t.GetSector();
+ RECALCULATE = kTRUE;
+ }
+ if(stk != fGeom->GetStack(z, ily)){
+ stk = fGeom->GetStack(z, ily);
+ RECALCULATE = kTRUE;
+ }
+ if(RECALCULATE){
+ det = AliTRDgeometry::GetDetector(ily, stk, sm);
+ if(!(matrix = fGeom->GetClusterMatrix(det))){
+ t.SetStatus(AliTRDtrackV1::kGeometry, ily);
+ continue;
+ }
+ matrix->LocalToMaster(loc, glb);
+ x = glb[0] - fgkMaxStep;
+ }
+
+ // check if track is well inside fiducial volume
+ if (!t.GetProlongation(x+fgkMaxStep, y, z)) {
+ n=-1;
+ t.SetStatus(AliTRDtrackV1::kProlongation);
+ break;
+ }
+ if(fGeom->IsOnBoundary(det, y, z, .5)){
+ t.SetStatus(AliTRDtrackV1::kBoundary, ily);
+ continue;
+ }
+ // mark track as entering the FIDUCIAL volume of TRD
if(kStoreIn){
t.SetTrackLow();
kStoreIn = kFALSE;
}
- Double_t maxChi2 = t.GetPredictedChi2(ptrTracklet);
- if (!t.Update(ptrTracklet, maxChi2)) return -1/*nClustersExpected*/;
- ptrTracklet->UpDate(&t);
- if (maxChi2<1e+10) {
- nClustersExpected += ptrTracklet->GetN();
- //t.SetTracklet(&tracklet, index);
+ ptrTracklet = tracklets[ily];
+ if(!ptrTracklet){ // BUILD TRACKLET
+ // check data in supermodule
+ if(!fTrSec[sm].GetNChambers()){
+ t.SetStatus(AliTRDtrackV1::kNoClusters, ily);
+ continue;
+ }
+ if(fTrSec[sm].GetX(ily) < 1.){
+ t.SetStatus(AliTRDtrackV1::kNoClusters, ily);
+ continue;
+ }
+
+ // check data in chamber
+ if(!(chamber = fTrSec[sm].GetChamber(stk, ily))){
+ t.SetStatus(AliTRDtrackV1::kNoClusters, ily);
+ continue;
+ }
+ if(chamber->GetNClusters() < fgNTimeBins*fReconstructor->GetRecoParam() ->GetFindableClusters()){
+ t.SetStatus(AliTRDtrackV1::kNoClusters, ily);
+ continue;
+ }
+ // build tracklet
+ ptrTracklet = new(&tracklet) AliTRDseedV1(det);
+ ptrTracklet->SetReconstructor(fReconstructor);
+ ptrTracklet->SetKink(t.IsKink());
+ ptrTracklet->SetPadPlane(fGeom->GetPadPlane(ily, stk));
+ ptrTracklet->SetX0(glb[0]+driftLength);
+ if(!tracklet.Init(&t)){
+ n=-1;
+ t.SetStatus(AliTRDtrackV1::kTrackletInit);
+ break;
+ }
+ if(!tracklet.AttachClusters(chamber, kTRUE)){
+ t.SetStatus(AliTRDtrackV1::kNoAttach, ily);
+ continue;
+ }
+ if(tracklet.GetN() < fgNTimeBins*fReconstructor->GetRecoParam() ->GetFindableClusters()){
+ t.SetStatus(AliTRDtrackV1::kNoClustersTracklet, ily);
+ continue;
+ }
+ ptrTracklet->UpdateUsed();
+ }
+ // propagate track to the radial position of the tracklet
+ ptrTracklet->UseClusters(); // TODO ? do we need this here ?
+ // fit tracklet no tilt correction
+ if(!ptrTracklet->Fit(kFALSE)){
+ t.SetStatus(AliTRDtrackV1::kNoFit, ily);
+ continue;
+ }
+ x = ptrTracklet->GetX(); //GetX0();
+ if(x > (fgkMaxStep + t.GetX()) && !PropagateToX(t, x, fgkMaxStep)) {
+ n=-1;
+ t.SetStatus(AliTRDtrackV1::kPropagation);
+ break;
+ }
+ if(!AdjustSector(&t)) {
+ n=-1;
+ t.SetStatus(AliTRDtrackV1::kAdjustSector);
+ break;
+ }
+ if(TMath::Abs(t.GetSnp()) > fgkMaxSnp) {
+ n=-1;
+ t.SetStatus(AliTRDtrackV1::kSnp);
+ break;
+ }
+ if(kPropagateIn){
+ t.SetTrackLow();
+ kPropagateIn = kFALSE;
+ }
+ Double_t cov[3]; ptrTracklet->GetCovAt(x, cov);
+ Double_t p[2] = { ptrTracklet->GetY(), ptrTracklet->GetZ()};
+ Double_t chi2 = ((AliExternalTrackParam)t).GetPredictedChi2(p, cov);
+ if(fReconstructor->GetStreamLevel(AliTRDReconstructor::kTracker) > 2){
+ Double_t ytrack = ptrTracklet->GetYref(0);
+ Double_t ztrack = ptrTracklet->GetZref(0);
+ Double_t ytracklet = ptrTracklet->GetYfit(0);
+ Double_t ztracklet = ptrTracklet->GetZfit(0);
+ Double_t phitrack = ptrTracklet->GetYref(1);
+ Double_t phitracklet = ptrTracklet->GetYfit(1);
+ Double_t thetatrack = ptrTracklet->GetZref(1);
+ Double_t thetatracklet = ptrTracklet->GetZfit(1);
+
+ TTreeSRedirector &mystreamer = *fReconstructor->GetDebugStream(AliTRDReconstructor::kTracker);
+ mystreamer << "FollowBackProlongation1"
+ << "il=" << ily
+ << "x=" << x
+ << "ytrack=" << ytrack
+ << "ztrack=" << ztrack
+ << "ytracklet=" << ytracklet
+ << "ztracklet=" << ztracklet
+ << "phitrack=" << phitrack
+ << "thetatrack=" << thetatrack
+ << "phitracklet=" << phitracklet
+ << "thetatracklet=" << thetatracklet
+ << "chi2=" << chi2
+ << "\n";
+ }
+ // update Kalman with the TRD measurement
+ if(chi2>1e+10){ // TODO
+ t.SetStatus(AliTRDtrackV1::kChi2, ily);
+ continue;
+ }
+ if(!t.Update(p, cov, chi2)) {
+ n=-1;
+ t.SetStatus(AliTRDtrackV1::kUpdate);
+ break;
}
+ // fill residuals ?!
+ AliTracker::FillResiduals(&t, p, cov, ptrTracklet->GetVolumeId());
+
+
+ // load tracklet to the tracker
+ ptrTracklet->Update(&t);
+ ptrTracklet = SetTracklet(ptrTracklet);
+ t.SetTracklet(ptrTracklet, fTracklets->GetEntriesFast()-1);
+ n += ptrTracklet->GetN();
+
// Reset material budget if 2 consecutive gold
- if(ilayer>0 && t.GetTracklet(ilayer-1) && ptrTracklet->GetN() + t.GetTracklet(ilayer-1)->GetN() > 20) t.SetBudget(2, 0.);
+// if(ilayer>0 && t.GetTracklet(ilayer-1) && ptrTracklet->GetN() + t.GetTracklet(ilayer-1)->GetN() > 20) t.SetBudget(2, 0.);
// Make backup of the track until is gold
// TO DO update quality check of the track.
// consider comparison with fTimeBinsRange
Float_t ratio0 = ptrTracklet->GetN() / Float_t(fgNTimeBins);
//Float_t ratio1 = Float_t(t.GetNumberOfClusters()+1) / Float_t(t.GetNExpected()+1);
- //printf("tracklet.GetChi2() %f [< 18.0]\n", tracklet.GetChi2());
- //printf("ratio0 %f [> 0.8]\n", ratio0);
- //printf("ratio1 %f [> 0.6]\n", ratio1);
- //printf("ratio0+ratio1 %f [> 1.5]\n", ratio0+ratio1);
- //printf("t.GetNCross() %d [== 0]\n", t.GetNCross());
- //printf("TMath::Abs(t.GetSnp()) %f [< 0.85]\n", TMath::Abs(t.GetSnp()));
- //printf("t.GetNumberOfClusters() %d [> 20]\n", t.GetNumberOfClusters());
- if (//(tracklet.GetChi2() < 18.0) && TO DO check with FindClusters and move it to AliTRDseed::Update
+ if( (chi2 < 18.0) &&
(ratio0 > 0.8) &&
//(ratio1 > 0.6) &&
//(ratio0+ratio1 > 1.5) &&
t.MakeBackupTrack();
}
} // end layers loop
+ //printf("clusters[%d] chi2[%f] x[%f] status[%d ", n, t.GetChi2(), t.GetX(), t.GetStatusTRD());
+ //for(int i=0; i<6; i++) printf("%d ", t.GetStatusTRD(i)); printf("]\n");
if(fReconstructor->GetStreamLevel(AliTRDReconstructor::kTracker) > 1){
TTreeSRedirector &cstreamer = *fReconstructor->GetDebugStream(AliTRDReconstructor::kTracker);
Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
- //AliTRDtrackV1 *debugTrack = new AliTRDtrackV1(t);
- //debugTrack->SetOwner();
+ AliTRDtrackV1 track(t);
+ track.SetOwner();
cstreamer << "FollowBackProlongation"
- << "EventNumber=" << eventNumber
- << "ncl=" << nClustersExpected
- //<< "track.=" << debugTrack
+ << "EventNumber=" << eventNumber
+ << "ncl=" << n
+ << "track.=" << &track
<< "\n";
}
- return nClustersExpected;
+ return n;
}
//_________________________________________________________________________
//
AliRieman *fitter = AliTRDtrackerV1::GetRiemanFitter();
fitter->Reset();
- for(Int_t i = 0; i < 4; i++)
- fitter->AddPoint(seedcl[i]->GetX(), seedcl[i]->GetY(), seedcl[i]->GetZ(), 1, 10);
+ for(Int_t i = 0; i < 4; i++){
+ fitter->AddPoint(seedcl[i]->GetX(), seedcl[i]->GetY(), seedcl[i]->GetZ(), 1., 10.);
+ }
fitter->Update();
Int_t nPoints = 0;
for(Int_t ilr = 0; ilr < AliTRDgeometry::kNlayer; ilr++){
if(!tracklets[ilr].IsOK()) continue;
- for(Int_t itb = 0; itb < AliTRDseedV1::kNTimeBins; itb++){
+ for(Int_t itb = 0; itb < AliTRDseedV1::kNclusters; itb++){
if(!tracklets[ilr].IsUsable(itb)) continue;
cl = tracklets[ilr].GetClusters(itb);
+ if(!cl->IsInChamber()) continue;
x = cl->GetX();
y = cl->GetY();
z = cl->GetZ();
uvt[0] = 2. * x * t;
uvt[1] = 2. * x * t * tilt ;
w = 2. * (y + tilt * (z - zVertex)) * t;
- error = 2. * TMath::Sqrt(cl->GetSigmaY2()) * t;
+ error = 2. * TMath::Sqrt(cl->GetSigmaY2()+tilt*tilt*cl->GetSigmaZ2()) * t;
fitter->AddPoint(uvt, w, error);
nPoints++;
}
AliTRDcluster *cl = 0x0;
Double_t xref = CalculateReferenceX(tracklets);
- Double_t x, y, z, t, tilt, dx, w, we;
- Double_t uvt[4];
+ Double_t x, y, z, t, tilt, dx, w, we, erry, errz;
+ Double_t uvt[4], sumPolY[5], sumPolZ[3];
+ memset(sumPolY, 0, sizeof(Double_t) * 5);
+ memset(sumPolZ, 0, sizeof(Double_t) * 3);
Int_t nPoints = 0;
// Containers for Least-square fitter
for(Int_t ipl = 0; ipl < kNPlanes; ipl++){
if(!tracklets[ipl].IsOK()) continue;
- for(Int_t itb = 0; itb < AliTRDseedV1::kNTimeBins; itb++){
+ tilt = tracklets[ipl].GetTilt();
+ for(Int_t itb = 0; itb < AliTRDseedV1::kNclusters; itb++){
if(!(cl = tracklets[ipl].GetClusters(itb))) continue;
+ if(!cl->IsInChamber()) continue;
if (!tracklets[ipl].IsUsable(itb)) continue;
x = cl->GetX();
y = cl->GetY();
z = cl->GetZ();
- tilt = tracklets[ipl].GetTilt();
dx = x - xref;
// Transformation
t = 1./(x*x + y*y);
w = 2. * (y + tilt*z) * t;
// error definition changes for the different calls
we = 2. * t;
- we *= sigError ? TMath::Sqrt(cl->GetSigmaY2()) : 0.2;
+ we *= sigError ? TMath::Sqrt(cl->GetSigmaY2()+tilt*tilt*cl->GetSigmaZ2()) : 0.2;
fitter->AddPoint(uvt, w, we);
zfitter.AddPoint(&x, z, static_cast<Double_t>(TMath::Sqrt(cl->GetSigmaZ2())));
+ // adding points for covariance matrix estimation
+ erry = 1./(TMath::Sqrt(cl->GetSigmaY2()) + 0.1); // 0.1 is a systematic error (due to misalignment and miscalibration)
+ erry *= erry;
+ errz = 1./cl->GetSigmaZ2();
+ for(Int_t ipol = 0; ipol < 5; ipol++){
+ sumPolY[ipol] += erry;
+ erry *= x;
+ if(ipol < 3){
+ sumPolZ[ipol] += errz;
+ errz *= x;
+ }
+ }
nPoints++;
}
}
Double_t chi2track = fitter->GetChisquare()/Double_t(nPoints);
+ // Prepare error calculation
+ TMatrixD covarPolY(3,3);
+ covarPolY(0,0) = sumPolY[0]; covarPolY(1,1) = sumPolY[2]; covarPolY(2,2) = sumPolY[4];
+ covarPolY(0,1) = covarPolY(1,0) = sumPolY[1];
+ covarPolY(0,2) = covarPolY(2,0) = sumPolY[2];
+ covarPolY(2,1) = covarPolY(1,2) = sumPolY[3];
+ covarPolY.Invert();
+ TMatrixD covarPolZ(2,2);
+ covarPolZ(0,0) = sumPolZ[0]; covarPolZ(1,1) = sumPolZ[2];
+ covarPolZ(1,0) = covarPolZ(0,1) = sumPolZ[1];
+ covarPolZ.Invert();
+
// Update the tracklets
- Double_t dy, dz;
+ Double_t x1, dy, dz;
+ Double_t cov[15];
+ memset(cov, 0, sizeof(Double_t) * 15);
for(Int_t iLayer = 0; iLayer < AliTRDtrackerV1::kNPlanes; iLayer++) {
x = tracklets[iLayer].GetX0();
+ x1 = x - xref;
y = 0;
z = 0;
dy = 0;
dz = 0;
-
+ memset(cov, 0, sizeof(Double_t) * 3);
+ TMatrixD transform(3,3);
+ transform(0,0) = 1;
+ transform(0,1) = x;
+ transform(0,2) = x*x;
+ transform(1,1) = 1;
+ transform(1,2) = x;
+ transform(2,2) = 1;
+ TMatrixD covariance(transform, TMatrixD::kMult, covarPolY);
+ covariance *= transform.T();
+ TMatrixD transformZ(2,2);
+ transformZ(0,0) = transformZ(1,1) = 1;
+ transformZ(0,1) = x;
+ TMatrixD covarZ(transformZ, TMatrixD::kMult, covarPolZ);
+ covarZ *= transformZ.T();
// y: R^2 = (x - x0)^2 + (y - y0)^2
// => y = y0 +/- Sqrt(R^2 - (x - x0)^2)
// R = Sqrt() = 1/Curvature
res = TMath::Sqrt(res);
y = (1.0 - res) / a;
}
+ cov[0] = covariance(0,0);
+ cov[2] = covarZ(0,0);
+ cov[1] = 0.;
// dy: R^2 = (x - x0)^2 + (y - y0)^2
// => y = +/- Sqrt(R^2 - (x - x0)^2) + y0
Double_t x0 = -b / a;
if (-c * a + b * b + 1 > 0) {
if (1.0/(curvature * curvature) - (x - x0) * (x - x0) > 0.0) {
- Double_t yderiv = (x - x0) / TMath::Sqrt(1.0/(curvature * curvature) - (x - x0) * (x - x0));
- if (a < 0) yderiv *= -1.0;
- dy = yderiv;
+ Double_t yderiv = (x - x0) / TMath::Sqrt(1.0/(curvature * curvature) - (x - x0) * (x - x0));
+ if (a < 0) yderiv *= -1.0;
+ dy = yderiv;
}
}
z = offset + slope * (x - xref);
tracklets[iLayer].SetZref(0, z);
tracklets[iLayer].SetZref(1, dz);
tracklets[iLayer].SetC(curvature);
+ tracklets[iLayer].SetCovRef(cov);
tracklets[iLayer].SetChi2(chi2track);
}
//_________________________________________________________________________
Double_t AliTRDtrackerV1::FitRiemanTilt(const AliTRDtrackV1 *track, AliTRDseedV1 *tracklets, Bool_t sigError, Int_t np, AliTrackPoint *points)
{
- //
- // Performs a Riemann fit taking tilting pad correction into account
- // The equation of a Riemann circle, where the y position is substituted by the
- // measured y-position taking pad tilting into account, has to be transformed
- // into a 4-dimensional hyperplane equation
- // Riemann circle: (x-x0)^2 + (y-y0)^2 -R^2 = 0
- // Measured y-Position: ymeas = y - tan(phiT)(zc - zt)
- // zc: center of the pad row
- // zt: z-position of the track
- // The z-position of the track is assumed to be linear dependent on the x-position
- // Transformed equation: a + b * u + c * t + d * v + e * w - 2 * (ymeas + tan(phiT) * zc) * t = 0
- // Transformation: u = 2 * x * t
- // v = 2 * tan(phiT) * t
- // w = 2 * tan(phiT) * (x - xref) * t
- // t = 1 / (x^2 + ymeas^2)
- // Parameters: a = -1/y0
- // b = x0/y0
- // c = (R^2 -x0^2 - y0^2)/y0
- // d = offset
- // e = dz/dx
- // If the offset respectively the slope in z-position is impossible, the parameters are fixed using
- // results from the simple riemann fit. Afterwards the fit is redone.
- // The curvature is calculated according to the formula:
- // curv = a/(1 + b^2 + c*a) = 1/R
- //
- // Paramters: - Array of tracklets (connected to the track candidate)
- // - Flag selecting the error definition
- // Output: - Chi2 values of the track (in Parameter list)
- //
+//
+// Performs a Riemann fit taking tilting pad correction into account
+//
+// Paramters: - Array of tracklets (connected to the track candidate)
+// - Flag selecting the error definition
+// Output: - Chi2 values of the track (in Parameter list)
+//
+// The equations which has to be solved simultaneously are:
+// BEGIN_LATEX
+// R^{2} = (x-x_{0})^{2} + (y^{*}-y_{0})^{2}
+// y^{*} = y - tg(h)(z - z_{t})
+// z_{t} = z_{0}+dzdx*(x-x_{r})
+// END_LATEX
+// with (x, y, z) the coordinate of the cluster, (x_0, y_0, z_0) the coordinate of the center of the Riemann circle,
+// R its radius, x_r a constant refrence radial position in the middle of the TRD stack and dzdx the slope of the
+// track in the x-z plane. Using the following transformations
+// BEGIN_LATEX
+// t = 1 / (x^{2} + y^{2})
+// u = 2 * x * t
+// v = 2 * tan(h) * t
+// w = 2 * tan(h) * (x - x_{r}) * t
+// END_LATEX
+// One gets the following linear equation
+// BEGIN_LATEX
+// a + b * u + c * t + d * v + e * w = 2 * (y + tg(h) * z) * t
+// END_LATEX
+// where the coefficients have the following meaning
+// BEGIN_LATEX
+// a = -1/y_{0}
+// b = x_{0}/y_{0}
+// c = (R^{2} -x_{0}^{2} - y_{0}^{2})/y_{0}
+// d = z_{0}
+// e = dz/dx
+// END_LATEX
+// The error calculation for the free term is thus
+// BEGIN_LATEX
+// #sigma = 2 * #sqrt{#sigma^{2}_{y} + (tilt corr ...) + tg^{2}(h) * #sigma^{2}_{z}} * t
+// END_LATEX
+//
+// From this simple model one can compute chi^2 estimates and a rough approximation of pt from the curvature according
+// to the formula:
+// BEGIN_LATEX
+// C = 1/R = a/(1 + b^{2} + c*a)
+// END_LATEX
+//
+// Authors
+// M.Ivanov <M.Ivanov@gsi.de>
+// A.Bercuci <A.Bercuci@gsi.de>
+// M.Fasel <M.Fasel@gsi.de>
+
TLinearFitter *fitter = GetTiltedRiemanFitter();
fitter->StoreData(kTRUE);
fitter->ClearPoints();
// Containers for Least-square fitter
for(Int_t ipl = 0; ipl < kNPlanes; ipl++){
if(!tracklets[ipl].IsOK()) continue;
- for(Int_t itb = 0; itb < AliTRDseedV1::kNTimeBins; itb++){
+ for(Int_t itb = 0; itb < AliTRDseedV1::kNclusters; itb++){
if(!(cl = tracklets[ipl].GetClusters(itb))) continue;
if (!tracklets[ipl].IsUsable(itb)) continue;
x = cl->GetX();
if (!AdjustSector(track)) break;
//Update track
- Double_t chi2 = track->GetPredictedChi2(ptrTracklet);
- if(chi2<1e+10) track->Update(ptrTracklet, chi2);
+ Double_t cov[3]; ptrTracklet->GetCovAt(x, cov);
+ Double_t p[2] = { ptrTracklet->GetY(), ptrTracklet->GetZ()};
+ Double_t chi2 = ((AliExternalTrackParam*)track)->GetPredictedChi2(p, cov);
+ if(chi2<1e+10) track->Update(p, cov, chi2);
if(!up) continue;
//Reset material budget if 2 consecutive gold
x = xpos + step;
// Get local Y and Z at the X-position of the next step
- if (!t.GetProlongation(x,y,z)) {
- return 0; // No prolongation possible
- }
+ if(t.GetProlongation(x,y,z)<0) return 0; // No prolongation possible
// The global position of the end point of this prolongation step
xyz1[0] = x * TMath::Cos(t.GetAlpha()) - y * TMath::Sin(t.GetAlpha());
Int_t nCluster = clusterArray->GetEntriesFast();
for (Int_t iCluster = 0; iCluster < nCluster; iCluster++) {
if(!(c = (AliTRDcluster *) clusterArray->UncheckedAt(iCluster))) continue;
- c->SetInChamber();
new((*fClusters)[ncl++]) AliTRDcluster(*c);
delete (clusterArray->RemoveAt(iCluster));
}
//____________________________________________________________________
void AliTRDtrackerV1::UnloadClusters()
{
- //
- // Clears the arrays of clusters and tracks. Resets sectors and timebins
- //
+//
+// Clears the arrays of clusters and tracks. Resets sectors and timebins
+// If option "force" is also set the containers are also deleted. This is useful
+// in case of HLT
- if(fTracks) fTracks->Delete();
- if(fTracklets) fTracklets->Delete();
+ if(fTracks){
+ fTracks->Delete();
+ if(HasRemoveContainers()){delete fTracks; fTracks = 0x0;}
+ }
+ if(fTracklets){
+ fTracklets->Delete();
+ if(HasRemoveContainers()){delete fTracklets; fTracklets = 0x0;}
+ }
if(fClusters){
if(IsClustersOwner()) fClusters->Delete();
// for(Int_t ily=AliTRDgeometry::kNlayer; ily--;){
// if(!(tracklet = track->GetTracklet(ily))) continue;
// AliTRDcluster *c = 0x0;
-// for(Int_t ic=AliTRDseed::knTimebins; ic--;){
+// for(Int_t ic=AliTRDseed::kNclusters; ic--;){
// if(!(c=tracklet->GetClusters(ic))) continue;
// c->Use();
// }
// Build initial seeding configurations
Double_t quality = BuildSeedingConfigs(stack, configs);
- if(fReconstructor->GetStreamLevel(AliTRDReconstructor::kTracker) > 1){
+ if(fReconstructor->GetStreamLevel(AliTRDReconstructor::kTracker) > 10){
AliInfo(Form("Plane config %d %d %d Quality %f"
, configs[0], configs[1], configs[2], quality));
}
pars[1] = ntracks;
pars[2] = istack;
ntracks = MakeSeeds(stack, &sseed[6*ntracks], pars);
+ //AliInfo(Form("Number of Tracks after iteration step %d: %d\n", iconf, ntracks));
if(ntracks == kMaxTracksStack) break;
}
if(fReconstructor->GetStreamLevel(AliTRDReconstructor::kTracker) > 1) AliInfo(Form("Candidate TRD tracks %d in iteration %d.", ntracks, fSieveSeeding));
Int_t jseed = kNPlanes*trackIndex+jLayer;
if(!sseed[jseed].IsOK()) continue;
if (TMath::Abs(sseed[jseed].GetYref(0) / sseed[jseed].GetX0()) < 0.158) findable++;
-
+ // TODO here we get a sig fault which should never happen !
sseed[jseed].UpdateUsed();
ncl += sseed[jseed].GetN2();
nused += sseed[jseed].GetNUsed();
trackParams[6] = fGeom->GetSector(chamber->GetDetector());/* *alpha+shift; // Supermodule*/
if(fReconstructor->GetStreamLevel(AliTRDReconstructor::kTracker) > 1){
- AliInfo(Form("Track %d [%d] nlayers %d trackQuality = %e nused %d, yref = %3.3f", itrack, trackIndex, nlayers, fTrackQuality[trackIndex], nused, trackParams[1]));
+ //AliInfo(Form("Track %d [%d] nlayers %d trackQuality = %e nused %d, yref = %3.3f", itrack, trackIndex, nlayers, fTrackQuality[trackIndex], nused, trackParams[1]));
AliTRDseedV1 *dseed[6];
- memcpy(dseed, lseed, 6*sizeof(AliTRDseedV1*));
+ for(Int_t iseed = AliTRDgeometry::kNlayer; iseed--;) dseed[iseed] = new AliTRDseedV1(lseed[iseed]);
//Int_t eventNrInFile = esd->GetEventNumberInFile();
- //AliInfo(Form("Number of clusters %d.", nclusters));
Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
Int_t trackNumber = AliTRDtrackerDebug::GetTrackNumber();
Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
chamber->Build(fGeom, cal);//Indices(fSieveSeeding);
}
- if(fReconstructor->GetStreamLevel(AliTRDReconstructor::kTracker) > 1){
+ if(fReconstructor->GetStreamLevel(AliTRDReconstructor::kTracker) > 10){
AliInfo(Form("Sieve level %d Plane config %d %d %d Quality %f", fSieveSeeding, configs[0], configs[1], configs[2], quality));
}
} while(fSieveSeeding<10); // end stack clusters sieve
// The overall chamber quality is given by the product of this 2 contributions.
//
- Double_t chamberQ[kNPlanes];
+ Double_t chamberQ[kNPlanes];memset(chamberQ, 0, kNPlanes*sizeof(Double_t));
AliTRDtrackingChamber *chamber = 0x0;
for(int iplane=0; iplane<kNPlanes; iplane++){
if(!(chamber = stack[iplane])) continue;
chamberQ[iplane] = (chamber = stack[iplane]) ? chamber->GetQuality() : 0.;
}
- Double_t tconfig[kNConfigs];
- Int_t planes[4];
+ Double_t tconfig[kNConfigs];memset(tconfig, 0, kNConfigs*sizeof(Double_t));
+ Int_t planes[] = {0, 0, 0, 0};
for(int iconf=0; iconf<kNConfigs; iconf++){
GetSeedingConfig(iconf, planes);
tconfig[iconf] = fgTopologicQA[iconf];
//____________________________________________________________________
Int_t AliTRDtrackerV1::MakeSeeds(AliTRDtrackingChamber **stack, AliTRDseedV1 *sseed, Int_t *ipar)
{
- //
- // Make tracklet seeds in the TRD stack.
- //
- // Parameters :
- // layers : Array of stack propagation layers containing clusters
- // sseed : Array of empty tracklet seeds. On exit they are filled.
- // ipar : Control parameters:
- // ipar[0] -> seeding chambers configuration
- // ipar[1] -> stack index
- // ipar[2] -> number of track candidates found so far
- //
- // Output :
- // Number of tracks candidates found.
- //
- // Detailed description
- //
- // The following steps are performed:
- // 1. Select seeding layers from seeding chambers
- // 2. Select seeding clusters from the seeding AliTRDpropagationLayerStack.
- // The clusters are taken from layer 3, layer 0, layer 1 and layer 2, in
- // this order. The parameters controling the range of accepted clusters in
- // layer 0, 1, and 2 are defined in AliTRDchamberTimeBin::BuildCond().
- // 3. Helix fit of the cluster set. (see AliTRDtrackerFitter::FitRieman(AliTRDcluster**))
- // 4. Initialize seeding tracklets in the seeding chambers.
- // 5. Filter 0.
- // Chi2 in the Y direction less than threshold ... (1./(3. - sLayer))
- // Chi2 in the Z direction less than threshold ... (1./(3. - sLayer))
- // 6. Attach clusters to seeding tracklets and find linear approximation of
- // the tracklet (see AliTRDseedV1::AttachClustersIter()). The number of used
- // clusters used by current seeds should not exceed ... (25).
- // 7. Filter 1.
- // All 4 seeding tracklets should be correctly constructed (see
- // AliTRDseedV1::AttachClustersIter())
- // 8. Helix fit of the seeding tracklets
- // 9. Filter 2.
- // Likelihood calculation of the fit. (See AliTRDtrackerV1::CookLikelihood() for details)
- // 10. Extrapolation of the helix fit to the other 2 chambers:
- // a) Initialization of extrapolation tracklet with fit parameters
- // b) Helix fit of tracklets
- // c) Attach clusters and linear interpolation to extrapolated tracklets
- // d) Helix fit of tracklets
- // 11. Improve seeding tracklets quality by reassigning clusters.
- // See AliTRDtrackerV1::ImproveSeedQuality() for details.
- // 12. Helix fit of all 6 seeding tracklets and chi2 calculation
- // 13. Hyperplane fit and track quality calculation. See AliTRDtrackerFitter::FitHyperplane() for details.
- // 14. Cooking labels for tracklets. Should be done only for MC
- // 15. Register seeds.
- //
+//
+// Seed tracklets and build candidate TRD tracks. The procedure is used during barrel tracking to account for tracks which are
+// either missed by TPC prolongation or conversions inside the TRD volume.
+// For stand alone tracking the procedure is used to estimate all tracks measured by TRD.
+//
+// Parameters :
+// layers : Array of stack propagation layers containing clusters
+// sseed : Array of empty tracklet seeds. On exit they are filled.
+// ipar : Control parameters:
+// ipar[0] -> seeding chambers configuration
+// ipar[1] -> stack index
+// ipar[2] -> number of track candidates found so far
+//
+// Output :
+// Number of tracks candidates found.
+//
+// The following steps are performed:
+// 1. Build seeding layers by collapsing all time bins from each of the four seeding chambers along the
+// radial coordinate. See AliTRDtrackingChamber::GetSeedingLayer() for details. The chambers selection for seeding
+// is described in AliTRDtrackerV1::Clusters2TracksStack().
+// 2. Using the seeding clusters from the seeding layer (step 1) build combinatorics using the following algorithm:
+// - for each seeding cluster in the lower seeding layer find
+// - all seeding clusters in the upper seeding layer inside a road defined by a given phi angle. The angle
+// is calculated on the minimum pt of tracks from vertex accesible to the stand alone tracker.
+// - for each pair of two extreme seeding clusters select middle upper cluster using roads defined externally by the
+// reco params
+// - select last seeding cluster as the nearest to the linear approximation of the track described by the first three
+// seeding clusters.
+// The implementation of road calculation and cluster selection can be found in the functions AliTRDchamberTimeBin::BuildCond()
+// and AliTRDchamberTimeBin::GetClusters().
+// 3. Helix fit of the seeding clusters set. (see AliTRDtrackerFitter::FitRieman(AliTRDcluster**)). No tilt correction is
+// performed at this level
+// 4. Initialize seeding tracklets in the seeding chambers.
+// 5. *Filter 0* Chi2 cut on the Y and Z directions. The threshold is set externally by the reco params.
+// 6. Attach (true) clusters to seeding tracklets (see AliTRDseedV1::AttachClusters()) and fit tracklet (see
+// AliTRDseedV1::Fit()). The number of used clusters used by current seeds should not exceed ... (25).
+// 7. *Filter 1* Check if all 4 seeding tracklets are correctly constructed.
+// 8. Helix fit of the clusters from the seeding tracklets with tilt correction. Refit tracklets using the new
+// approximation of the track.
+// 9. *Filter 2* Calculate likelihood of the track. (See AliTRDtrackerV1::CookLikelihood()). The following quantities are
+// checked against the Riemann fit:
+// - position resolution in y
+// - angular resolution in the bending plane
+// - likelihood of the number of clusters attached to the tracklet
+// 10. Extrapolation of the helix fit to the other 2 chambers *non seeding* chambers:
+// - Initialization of extrapolation tracklets with the fit parameters
+// - Attach clusters to extrapolated tracklets
+// - Helix fit of tracklets
+// 11. Improve seeding tracklets quality by reassigning clusters based on the last parameters of the track
+// See AliTRDtrackerV1::ImproveSeedQuality() for details.
+// 12. Helix fit of all 6 seeding tracklets and chi2 calculation
+// 13. Hyperplane fit and track quality calculation. See AliTRDtrackerFitter::FitHyperplane() for details.
+// 14. Cooking labels for tracklets. Should be done only for MC
+// 15. Register seeds.
+//
+// Authors:
+// Marian Ivanov <M.Ivanov@gsi.de>
+// Alexandru Bercuci <A.Bercuci@gsi.de>
+// Markus Fasel <M.Fasel@gsi.de>
AliTRDtrackingChamber *chamber = 0x0;
AliTRDcluster *c[kNSeedPlanes] = {0x0, 0x0, 0x0, 0x0}; // initilize seeding clusters
// chi2[1] = tracklet chi2 on the R direction
Double_t chi2[4];
- // Default positions for the anode wire in all 6 Layers in case of a stack with missing clusters
- // Positions taken using cosmic data taken with SM3 after rebuild
- Double_t x_def[kNPlanes] = {300.2, 312.8, 325.4, 338.0, 350.6, 363.2};
-
- // this should be data member of AliTRDtrack
+ // this should be data member of AliTRDtrack TODO
Double_t seedQuality[kMaxTracksStack];
// unpack control parameters
Int_t ntracks = ipar[1];
Int_t istack = ipar[2];
Int_t planes[kNSeedPlanes]; GetSeedingConfig(config, planes);
- Int_t planesExt[kNPlanes-kNSeedPlanes]; GetExtrapolationConfig(config, planesExt);
+ Int_t planesExt[kNPlanes-kNSeedPlanes]; GetExtrapolationConfig(config, planesExt);
// Init chambers geometry
Double_t hL[kNPlanes]; // Tilting angle
Float_t padlength[kNPlanes]; // pad lenghts
+ Float_t padwidth[kNPlanes]; // pad widths
AliTRDpadPlane *pp = 0x0;
for(int iplane=0; iplane<kNPlanes; iplane++){
pp = fGeom->GetPadPlane(iplane, istack);
hL[iplane] = TMath::Tan(TMath::DegToRad()*pp->GetTiltingAngle());
padlength[iplane] = pp->GetLengthIPad();
+ padwidth[iplane] = pp->GetWidthIPad();
+ }
+
+ // Init anode wire position for chambers
+ Double_t x0[kNPlanes], // anode wire position
+ driftLength = .5*AliTRDgeometry::AmThick() - AliTRDgeometry::DrThick(); // drift length
+ TGeoHMatrix *matrix = 0x0;
+ Double_t loc[] = {AliTRDgeometry::AnodePos(), 0., 0.};
+ Double_t glb[] = {0., 0., 0.};
+ AliTRDtrackingChamber **cIter = &stack[0];
+ for(int iLayer=0; iLayer<kNPlanes; iLayer++,cIter++){
+ if(!(*cIter)) continue;
+ if(!(matrix = fGeom->GetClusterMatrix((*cIter)->GetDetector()))){
+ continue;
+ x0[iLayer] = fgkX0[iLayer];
+ }
+ matrix->LocalToMaster(loc, glb);
+ x0[iLayer] = glb[0];
}
-
- if(fReconstructor->GetStreamLevel(AliTRDReconstructor::kTracker) > 1){
+
+ if(fReconstructor->GetStreamLevel(AliTRDReconstructor::kTracker) > 2){
AliInfo(Form("Making seeds Stack[%d] Config[%d] Tracks[%d]...", istack, config, ntracks));
}
if(!chamber->GetSeedingLayer(fSeedTB[isl], fGeom, fReconstructor)) continue;
nlayers++;
}
- if(nlayers < 4) return ntracks;
+ if(nlayers < kNSeedPlanes) return ntracks;
// Start finding seeds
c[0] = (*fSeedTB[0])[index[jcl++]];
if(!c[0]) continue;
Double_t dx = c[3]->GetX() - c[0]->GetX();
- Double_t theta = (c[3]->GetZ() - c[0]->GetZ())/dx;
- Double_t phi = (c[3]->GetY() - c[0]->GetY())/dx;
- fSeedTB[1]->BuildCond(c[0], cond1, 1, theta, phi);
+ Double_t dzdx = (c[3]->GetZ() - c[0]->GetZ())/dx;
+ Double_t dydx = (c[3]->GetY() - c[0]->GetY())/dx;
+ fSeedTB[1]->BuildCond(c[0], cond1, 1, dzdx, dydx);
fSeedTB[1]->GetClusters(cond1, jndex, mcl);
//printf("Found c[0] candidates 1 %d\n", mcl);
while(kcl<mcl) {
c[1] = (*fSeedTB[1])[jndex[kcl++]];
if(!c[1]) continue;
- fSeedTB[2]->BuildCond(c[1], cond2, 2, theta, phi);
+ fSeedTB[2]->BuildCond(c[1], cond2, 2, dzdx, dydx);
c[2] = fSeedTB[2]->GetNearestCluster(cond2);
//printf("Found c[1] candidate 2 %p\n", c[2]);
if(!c[2]) continue;
- // AliInfo("Seeding clusters found. Building seeds ...");
- // for(Int_t i = 0; i < kNSeedPlanes; i++) printf("%i. coordinates: x = %6.3f, y = %6.3f, z = %6.3f\n", i, c[i]->GetX(), c[i]->GetY(), c[i]->GetZ());
+ //AliInfo("Seeding clusters found. Building seeds ...");
+ //for(Int_t i = 0; i < kNSeedPlanes; i++) printf("%i. coordinates: x = %6.3f, y = %6.3f, z = %6.3f\n", i, c[i]->GetX(), c[i]->GetY(), c[i]->GetZ());
for (Int_t il = 0; il < kNPlanes; il++) cseed[il].Reset();
FitRieman(c, chi2);
AliTRDseedV1 *tseed = &cseed[0];
- AliTRDtrackingChamber **cIter = &stack[0];
+ cIter = &stack[0];
for(int iLayer=0; iLayer<kNPlanes; iLayer++, tseed++, cIter++){
- tseed->SetDetector((*cIter) ? (*cIter)->GetDetector() : -1);
+ Int_t det = (*cIter) ? (*cIter)->GetDetector() : -1;
+ tseed->SetDetector(det);
tseed->SetTilt(hL[iLayer]);
tseed->SetPadLength(padlength[iLayer]);
+ tseed->SetPadWidth(padwidth[iLayer]);
tseed->SetReconstructor(fReconstructor);
- tseed->SetX0((*cIter) ? (*cIter)->GetX() : x_def[iLayer]);
+ tseed->SetX0(det<0 ? fR[iLayer]+driftLength : x0[iLayer]);
tseed->Init(GetRiemanFitter());
tseed->SetStandAlone(kTRUE);
}
<<"\n";
}
if(chi2[0] > fReconstructor->GetRecoParam() ->GetChi2Z()/*7./(3. - sLayer)*//*iter*/){
-// //AliInfo(Form("Failed chi2 filter on chi2Z [%f].", chi2[0]));
+ //AliInfo(Form("Failed chi2 filter on chi2Z [%f].", chi2[0]));
AliTRDtrackerDebug::SetCandidateNumber(AliTRDtrackerDebug::GetCandidateNumber() + 1);
continue;
}
if(chi2[1] > fReconstructor->GetRecoParam() ->GetChi2Y()/*1./(3. - sLayer)*//*iter*/){
-// //AliInfo(Form("Failed chi2 filter on chi2Y [%f].", chi2[1]));
+ //AliInfo(Form("Failed chi2 filter on chi2Y [%f].", chi2[1]));
AliTRDtrackerDebug::SetCandidateNumber(AliTRDtrackerDebug::GetCandidateNumber() + 1);
continue;
}
//AliInfo("Passed chi2 filter.");
// try attaching clusters to tracklets
- Int_t mlayers = 0;
+ Int_t mlayers = 0;
+ AliTRDcluster *cl = NULL;
for(int iLayer=0; iLayer<kNSeedPlanes; iLayer++){
Int_t jLayer = planes[iLayer];
+ Int_t nNotInChamber = 0;
if(!cseed[jLayer].AttachClusters(stack[jLayer], kTRUE)) continue;
+ cseed[jLayer].Fit();
cseed[jLayer].UpdateUsed();
- if(!cseed[jLayer].IsOK()) continue;
+ cseed[jLayer].ResetClusterIter();
+ while((cl = cseed[jLayer].NextCluster())){
+ if(!cl->IsInChamber()) nNotInChamber++;
+ }
+ //printf("clusters[%d], used[%d], not in chamber[%d]\n", cseed[jLayer].GetN(), cseed[jLayer].GetNUsed(), nNotInChamber);
+ 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
mlayers++;
}
Int_t jLayer = planesExt[iLayer];
if(!(chamber = stack[jLayer])) continue;
cseed[jLayer].AttachClusters(chamber, kTRUE);
+ cseed[jLayer].Fit();
}
fTrackQuality[ntracks] = 1.; // dummy value
ntracks++;
<< "\n";
}
- if(fReconstructor->GetRecoParam()->HasImproveTracklets() && ImproveSeedQuality(stack, cseed) < 4){
+ if(fReconstructor->HasImproveTracklets() && ImproveSeedQuality(stack, cseed) < 4){
AliTRDtrackerDebug::SetCandidateNumber(AliTRDtrackerDebug::GetCandidateNumber() + 1);
continue;
}
// do the final track fitting (Once with vertex constraint and once without vertex constraint)
Double_t chi2Vals[3];
- chi2Vals[0] = FitTiltedRieman(&cseed[0], kFALSE);
- if(fReconstructor->GetRecoParam()->IsVertexConstrained())
+ chi2Vals[0] = FitTiltedRieman(&cseed[0], kTRUE);
+ if(fReconstructor->HasVertexConstrained())
chi2Vals[1] = FitTiltedRiemanConstraint(&cseed[0], GetZ()); // Do Vertex Constrained fit if desired
else
chi2Vals[1] = 1.;
//_____________________________________________________________________________
AliTRDtrackV1* AliTRDtrackerV1::MakeTrack(AliTRDseedV1 *seeds, Double_t *params)
{
- //
- // Build a TRD track out of tracklet candidates
- //
- // Parameters :
- // seeds : array of tracklets
- // params : track parameters (see MakeSeeds() function body for a detailed description)
- //
- // Output :
- // The TRD track.
- //
- // Detailed description
- //
- // To be discussed with Marian !!
- //
-
+//
+// Build a TRD track out of tracklet candidates
+//
+// Parameters :
+// seeds : array of tracklets
+// params : array of track parameters as they are estimated by stand alone tracker. 7 elements.
+// [0] - radial position of the track at reference point
+// [1] - y position of the fit at [0]
+// [2] - z position of the fit at [0]
+// [3] - snp of the first tracklet
+// [4] - tgl of the first tracklet
+// [5] - curvature of the Riemann fit - 1/pt
+// [6] - sector rotation angle
+//
+// Output :
+// The TRD track.
+//
+// Initialize the TRD track based on the parameters of the fit and a parametric covariance matrix
+// (diagonal with constant variance terms TODO - correct parameterization)
+//
+// In case of HLT just register the tracklets in the tracker and return values of the Riemann fit. For the
+// offline case perform a full Kalman filter on the already found tracklets (see AliTRDtrackerV1::FollowBackProlongation()
+// for details). Do also MC label calculation and PID if propagation successfully.
+
Double_t alpha = AliTRDgeometry::GetAlpha();
Double_t shift = AliTRDgeometry::GetAlpha()/2.0;
Double_t c[15];
- c[ 0] = 0.2;
- c[ 1] = 0.0; c[ 2] = 2.0;
- c[ 3] = 0.0; c[ 4] = 0.0; c[ 5] = 0.02;
- c[ 6] = 0.0; c[ 7] = 0.0; c[ 8] = 0.0; c[ 9] = 0.1;
- c[10] = 0.0; c[11] = 0.0; c[12] = 0.0; c[13] = 0.0; c[14] = params[5]*params[5]*0.01;
+ c[ 0] = 0.2; // s^2_y
+ c[ 1] = 0.0; c[ 2] = 2.0; // s^2_z
+ c[ 3] = 0.0; c[ 4] = 0.0; c[ 5] = 0.02; // s^2_snp
+ c[ 6] = 0.0; c[ 7] = 0.0; c[ 8] = 0.0; c[ 9] = 0.1; // s^2_tgl
+ c[10] = 0.0; c[11] = 0.0; c[12] = 0.0; c[13] = 0.0; c[14] = params[5]*params[5]*0.01; // s^2_1/pt
AliTRDtrackV1 track(seeds, ¶ms[1], c, params[0], params[6]*alpha+shift);
track.PropagateTo(params[0]-5.0);
AliTRDseedV1 *ptrTracklet = 0x0;
- // Sign clusters
- for (Int_t jLayer = 0; jLayer < AliTRDgeometry::kNlayer; jLayer++) {
- ptrTracklet = &seeds[jLayer];
- if(!ptrTracklet->IsOK()) continue;
- if(TMath::Abs(ptrTracklet->GetYref(1) - ptrTracklet->GetYfit(1)) >= .2) continue; // check this condition with Marian
- }
- //
+
+ // skip Kalman filter for HLT
if(fReconstructor->IsHLT()){
- for(Int_t ip=0; ip<kNPlanes; ip++){
- track.UnsetTracklet(ip);
- ptrTracklet = SetTracklet(&seeds[ip]);
+ for (Int_t jLayer = 0; jLayer < AliTRDgeometry::kNlayer; jLayer++) {
+ track.UnsetTracklet(jLayer);
+ ptrTracklet = &seeds[jLayer];
+ if(!ptrTracklet->IsOK()) continue;
+ if(TMath::Abs(ptrTracklet->GetYref(1) - ptrTracklet->GetYfit(1)) >= .2) continue; // check this condition with Marian
+ ptrTracklet = SetTracklet(ptrTracklet);
ptrTracklet->UseClusters();
track.SetTracklet(ptrTracklet, fTracklets->GetEntriesFast()-1);
}
AliTRDtrackV1 *ptrTrack = SetTrack(&track);
+ ptrTrack->CookPID();
ptrTrack->SetReconstructor(fReconstructor);
return ptrTrack;
}
chi2phi /= Float_t (nLayers - 2.0);
Double_t likeChi2Z = TMath::Exp(-chi2[2] * 0.14); // Chi2Z
- Double_t likeChi2TC = (fReconstructor->GetRecoParam() ->IsVertexConstrained()) ?
+ Double_t likeChi2TC = (fReconstructor->HasVertexConstrained()) ?
TMath::Exp(-chi2[1] * 0.677) : 1; // Constrained Tilted Riemann
- Double_t likeChi2TR = TMath::Exp(-chi2[0] * 0.78); // Non-constrained Tilted Riemann
- Double_t likeChi2Phi= TMath::Exp(-chi2phi * 3.23);
+ Double_t likeChi2TR = TMath::Exp(-chi2[0] * 0.0078); // Non-constrained Tilted Riemann
+ Double_t likeChi2Phi= TMath::Exp(-chi2phi * 3.23);//3.23
Double_t trackLikelihood = likeChi2Z * likeChi2TR * likeChi2Phi;
if(fReconstructor->GetStreamLevel(AliTRDReconstructor::kTracker) >= 2){
<< "TrackLikelihood=" << trackLikelihood
<< "\n";
}
-
+
return trackLikelihood;
}
Double_t likeN = TMath::Exp(-(fRecoPars->GetNMeanClusters() - nclusters) / fRecoPars->GetNSigmaClusters());
Double_t like = likea * likechi2y * likechi2z * likeN;
- // AliInfo(Form("sumda(%f) chi2[0](%f) chi2[1](%f) likea(%f) likechi2y(%f) likechi2z(%f) nclusters(%d) likeN(%f)", sumda, chi2[0], chi2[1], likea, likechi2y, likechi2z, nclusters, likeN));
if(fReconstructor->GetStreamLevel(AliTRDReconstructor::kTracker) >= 2){
Int_t eventNumber = AliTRDtrackerDebug::GetEventNumber();
Int_t candidateNumber = AliTRDtrackerDebug::GetCandidateNumber();
return idx >= 0 && idx < ntrk ? (AliKalmanTrack*)fTracks->UncheckedAt(idx) : 0x0;
}
-//____________________________________________________________________
-Float_t AliTRDtrackerV1::CalculateReferenceX(AliTRDseedV1 *tracklets){
- //
- // Calculates the reference x-position for the tilted Rieman fit defined as middle
- // of the stack (middle between layers 2 and 3). For the calculation all the tracklets
- // are taken into account
- //
- // Parameters: - Array of tracklets(AliTRDseedV1)
- //
- // Output: - The reference x-position(Float_t)
- //
- Int_t nDistances = 0;
- Float_t meanDistance = 0.;
- Int_t startIndex = 5;
- for(Int_t il =5; il > 0; il--){
- if(tracklets[il].IsOK() && tracklets[il -1].IsOK()){
- Float_t xdiff = tracklets[il].GetX0() - tracklets[il -1].GetX0();
- meanDistance += xdiff;
- nDistances++;
- }
- if(tracklets[il].IsOK()) startIndex = il;
- }
- if(tracklets[0].IsOK()) startIndex = 0;
- if(!nDistances){
- // We should normally never get here
- Float_t xpos[2]; memset(xpos, 0, sizeof(Float_t) * 2);
- Int_t iok = 0, idiff = 0;
- // This attempt is worse and should be avoided:
- // check for two chambers which are OK and repeat this without taking the mean value
- // Strategy avoids a division by 0;
- for(Int_t il = 5; il >= 0; il--){
- if(tracklets[il].IsOK()){
- xpos[iok] = tracklets[il].GetX0();
- iok++;
- startIndex = il;
- }
- if(iok) idiff++; // to get the right difference;
- if(iok > 1) break;
- }
- if(iok > 1){
- meanDistance = (xpos[0] - xpos[1])/idiff;
- }
- else{
- // we have do not even have 2 layers which are OK? The we do not need to fit at all
- return 331.;
- }
- }
- else{
- meanDistance /= nDistances;
- }
- return tracklets[startIndex].GetX0() + (2.5 - startIndex) * meanDistance - 0.5 * (AliTRDgeometry::AmThick() + AliTRDgeometry::DrThick());
-}
+
// //_____________________________________________________________________________
// Int_t AliTRDtrackerV1::Freq(Int_t n, const Int_t *inlist
return n ? chi2/n : 0.;
}
+//____________________________________________________________________
+Float_t AliTRDtrackerV1::CalculateReferenceX(AliTRDseedV1 *tracklets){
+ //
+ // Calculates the reference x-position for the tilted Rieman fit defined as middle
+ // of the stack (middle between layers 2 and 3). For the calculation all the tracklets
+ // are taken into account
+ //
+ // Parameters: - Array of tracklets(AliTRDseedV1)
+ //
+ // Output: - The reference x-position(Float_t)
+ // Only kept for compatibility with the old code
+ //
+ Int_t nDistances = 0;
+ Float_t meanDistance = 0.;
+ Int_t startIndex = 5;
+ for(Int_t il =5; il > 0; il--){
+ if(tracklets[il].IsOK() && tracklets[il -1].IsOK()){
+ Float_t xdiff = tracklets[il].GetX0() - tracklets[il -1].GetX0();
+ meanDistance += xdiff;
+ nDistances++;
+ }
+ if(tracklets[il].IsOK()) startIndex = il;
+ }
+ if(tracklets[0].IsOK()) startIndex = 0;
+ if(!nDistances){
+ // We should normally never get here
+ Float_t xpos[2]; memset(xpos, 0, sizeof(Float_t) * 2);
+ Int_t iok = 0, idiff = 0;
+ // This attempt is worse and should be avoided:
+ // check for two chambers which are OK and repeat this without taking the mean value
+ // Strategy avoids a division by 0;
+ for(Int_t il = 5; il >= 0; il--){
+ if(tracklets[il].IsOK()){
+ xpos[iok] = tracklets[il].GetX0();
+ iok++;
+ startIndex = il;
+ }
+ if(iok) idiff++; // to get the right difference;
+ if(iok > 1) break;
+ }
+ if(iok > 1){
+ meanDistance = (xpos[0] - xpos[1])/idiff;
+ }
+ else{
+ // we have do not even have 2 layers which are OK? The we do not need to fit at all
+ return 331.;
+ }
+ }
+ else{
+ meanDistance /= nDistances;
+ }
+ return tracklets[startIndex].GetX0() + (2.5 - startIndex) * meanDistance - 0.5 * (AliTRDgeometry::AmThick() + AliTRDgeometry::DrThick());
+}
+
+//_____________________________________________________________________________
+Double_t AliTRDtrackerV1::FitTiltedRiemanV1(AliTRDseedV1 *tracklets){
+ //
+ // Track Fitter Function using the new class implementation of
+ // the Rieman fit
+ //
+ AliTRDtrackFitterRieman fitter;
+ fitter.SetRiemanFitter(GetTiltedRiemanFitter());
+ fitter.Reset();
+ for(Int_t il = 0; il < AliTRDgeometry::kNlayer; il++) fitter.SetTracklet(il, &tracklets[il]);
+ Double_t chi2 = fitter.Eval();
+ // Update the tracklets
+ Double_t cov[15]; Double_t x0;
+ memset(cov, 0, sizeof(Double_t) * 15);
+ for(Int_t il = 0; il < AliTRDgeometry::kNlayer; il++){
+ x0 = tracklets[il].GetX0();
+ tracklets[il].SetYref(0, fitter.GetYat(x0));
+ tracklets[il].SetZref(0, fitter.GetZat(x0));
+ tracklets[il].SetYref(1, fitter.GetDyDxAt(x0));
+ tracklets[il].SetZref(1, fitter.GetDzDx());
+ tracklets[il].SetC(fitter.GetCurvature());
+ fitter.GetCovAt(x0, cov);
+ tracklets[il].SetCovRef(cov);
+ tracklets[il].SetChi2(chi2);
+ }
+ return chi2;
+}
+
///////////////////////////////////////////////////////
// //
// Resources of class AliTRDLeastSquare //
//
// Adding Point to the fitter
//
- Double_t weight = 1/(sigmaY * sigmaY);
+ Double_t weight = 1/(sigmaY > 1e-9 ? sigmaY : 1e-9);
+ weight *= weight;
Double_t &xpt = *x;
// printf("Adding point x = %f, y = %f, sigma = %f\n", xpt, y, sigmaY);
fSums[0] += weight;
//
// Remove Point from the sample
//
- Double_t weight = 1/(sigmaY * sigmaY);
+
+ Double_t weight = 1/(sigmaY > 1e-9 ? sigmaY : 1e-9);
+ weight *= weight;
Double_t &xpt = *x;
fSums[0] -= weight;
fSums[1] -= weight * xpt;
// printf("fParams[0] = %f, fParams[1] = %f\n", fParams[0], fParams[1]);
// Covariance matrix
- fCovarianceMatrix[0] = fSums[4] - fSums[1] * fSums[1] / fSums[0];
- fCovarianceMatrix[1] = fSums[5] - fSums[2] * fSums[2] / fSums[0];
- fCovarianceMatrix[2] = fSums[3] - fSums[1] * fSums[2] / fSums[0];
+ fCovarianceMatrix[0] = fSums[4] / fSums[0] - fSums[1] * fSums[1] / (fSums[0] * fSums[0]);
+ fCovarianceMatrix[1] = fSums[5] / fSums[0] - fSums[2] * fSums[2] / (fSums[0] * fSums[0]);
+ fCovarianceMatrix[2] = fSums[3] / fSums[0] - fSums[1] * fSums[2] / (fSums[0] * fSums[0]);
}
//_____________________________________________________________________________
memcpy(storage, fCovarianceMatrix, sizeof(Double_t) * 3);
}
+//_____________________________________________________________________________
+void AliTRDtrackerV1::AliTRDLeastSquare::Reset(){
+ //
+ // Reset the fitter
+ //
+ memset(fParams, 0, sizeof(Double_t) * 2);
+ memset(fCovarianceMatrix, 0, sizeof(Double_t) * 3);
+ memset(fSums, 0, sizeof(Double_t) * 6);
+}
+
+///////////////////////////////////////////////////////
+// //
+// Resources of class AliTRDtrackFitterRieman //
+// //
+///////////////////////////////////////////////////////
+
+//_____________________________________________________________________________
+AliTRDtrackerV1::AliTRDtrackFitterRieman::AliTRDtrackFitterRieman():
+ fTrackFitter(NULL),
+ fZfitter(NULL),
+ fCovarPolY(NULL),
+ fCovarPolZ(NULL),
+ fXref(0.),
+ fSysClusterError(0.)
+{
+ //
+ // Default constructor
+ //
+ fZfitter = new AliTRDLeastSquare;
+ fCovarPolY = new TMatrixD(3,3);
+ fCovarPolZ = new TMatrixD(2,2);
+ memset(fTracklets, 0, sizeof(AliTRDseedV1 *) * 6);
+ memset(fParameters, 0, sizeof(Double_t) * 5);
+ memset(fSumPolY, 0, sizeof(Double_t) * 5);
+ memset(fSumPolZ, 0, sizeof(Double_t) * 2);
+}
+
+//_____________________________________________________________________________
+AliTRDtrackerV1::AliTRDtrackFitterRieman::~AliTRDtrackFitterRieman(){
+ //
+ // Destructor
+ //
+ if(fZfitter) delete fZfitter;
+ if(fCovarPolY) delete fCovarPolY;
+ if(fCovarPolZ) delete fCovarPolZ;
+}
+
+//_____________________________________________________________________________
+void AliTRDtrackerV1::AliTRDtrackFitterRieman::Reset(){
+ //
+ // Reset the Fitter
+ //
+ if(fTrackFitter){
+ fTrackFitter->StoreData(kTRUE);
+ fTrackFitter->ClearPoints();
+ }
+ if(fZfitter){
+ fZfitter->Reset();
+ }
+ fXref = 0.;
+ memset(fTracklets, 0, sizeof(AliTRDseedV1 *) * AliTRDgeometry::kNlayer);
+ memset(fParameters, 0, sizeof(Double_t) * 5);
+ memset(fSumPolY, 0, sizeof(Double_t) * 5);
+ memset(fSumPolZ, 0, sizeof(Double_t) * 2);
+ for(Int_t irow = 0; irow < fCovarPolY->GetNrows(); irow++)
+ for(Int_t icol = 0; icol < fCovarPolY->GetNcols(); icol++){
+ (*fCovarPolY)(irow, icol) = 0.;
+ if(irow < 2 && icol < 2)
+ (*fCovarPolZ)(irow, icol) = 0.;
+ }
+}
+
+//_____________________________________________________________________________
+void AliTRDtrackerV1::AliTRDtrackFitterRieman::SetTracklet(Int_t itr, AliTRDseedV1 *tracklet){
+ //
+ // Add tracklet into the fitter
+ //
+ if(itr >= AliTRDgeometry::kNlayer) return;
+ fTracklets[itr] = tracklet;
+}
+
+//_____________________________________________________________________________
+Double_t AliTRDtrackerV1::AliTRDtrackFitterRieman::Eval(){
+ //
+ // Perform the fit
+ // 1. Apply linear transformation and store points in the fitter
+ // 2. Evaluate the fit
+ // 3. Check if the result of the fit in z-direction is reasonable
+ // if not
+ // 3a. Fix the parameters 3 and 4 with the results of a simple least
+ // square fit
+ // 3b. Redo the fit with the fixed parameters
+ // 4. Store fit results (parameters and errors)
+ //
+ if(!fTrackFitter){
+ return 1e10;
+ }
+ fXref = CalculateReferenceX();
+ for(Int_t il = 0; il < AliTRDgeometry::kNlayer; il++) UpdateFitters(fTracklets[il]);
+ if(!fTrackFitter->GetNpoints()) return 1e10;
+ // perform the fit
+ fTrackFitter->Eval();
+ fZfitter->Eval();
+ fParameters[3] = fTrackFitter->GetParameter(3);
+ fParameters[4] = fTrackFitter->GetParameter(4);
+ if(!CheckAcceptable(fParameters[3], fParameters[4])) {
+ fTrackFitter->FixParameter(3, fZfitter->GetFunctionValue(&fXref));
+ fTrackFitter->FixParameter(4, fZfitter->GetFunctionParameter(1));
+ fTrackFitter->Eval();
+ fTrackFitter->ReleaseParameter(3);
+ fTrackFitter->ReleaseParameter(4);
+ fParameters[3] = fTrackFitter->GetParameter(3);
+ fParameters[4] = fTrackFitter->GetParameter(4);
+ }
+ // Update the Fit Parameters and the errors
+ fParameters[0] = fTrackFitter->GetParameter(0);
+ fParameters[1] = fTrackFitter->GetParameter(1);
+ fParameters[2] = fTrackFitter->GetParameter(2);
+
+ // Prepare Covariance estimation
+ (*fCovarPolY)(0,0) = fSumPolY[0]; (*fCovarPolY)(1,1) = fSumPolY[2]; (*fCovarPolY)(2,2) = fSumPolY[4];
+ (*fCovarPolY)(1,0) = (*fCovarPolY)(0,1) = fSumPolY[1];
+ (*fCovarPolY)(2,0) = (*fCovarPolY)(0,2) = fSumPolY[2];
+ (*fCovarPolY)(2,1) = (*fCovarPolY)(1,2) = fSumPolY[3];
+ fCovarPolY->Invert();
+ (*fCovarPolZ)(0,0) = fSumPolZ[0]; (*fCovarPolZ)(1,1) = fSumPolZ[2];
+ (*fCovarPolZ)(1,0) = (*fCovarPolZ)(0,1) = fSumPolZ[1];
+ fCovarPolZ->Invert();
+ return fTrackFitter->GetChisquare() / fTrackFitter->GetNpoints();
+}
+
+//_____________________________________________________________________________
+void AliTRDtrackerV1::AliTRDtrackFitterRieman::UpdateFitters(AliTRDseedV1 *tracklet){
+ //
+ // Does the transformations and updates the fitters
+ // The following transformation is applied
+ //
+ AliTRDcluster *cl = NULL;
+ Double_t x, y, z, dx, t, w, we, yerr, zerr;
+ Double_t uvt[4];
+ if(!tracklet || !tracklet->IsOK()) return;
+ Double_t tilt = tracklet->GetTilt();
+ for(Int_t itb = 0; itb < AliTRDseedV1::kNclusters; itb++){
+ if(!(cl = tracklet->GetClusters(itb))) continue;
+ if(!cl->IsInChamber()) continue;
+ if (!tracklet->IsUsable(itb)) continue;
+ x = cl->GetX();
+ y = cl->GetY();
+ z = cl->GetZ();
+ dx = x - fXref;
+ // Transformation
+ t = 1./(x*x + y*y);
+ uvt[0] = 2. * x * t;
+ uvt[1] = t;
+ uvt[2] = 2. * tilt * t;
+ uvt[3] = 2. * tilt * dx * t;
+ w = 2. * (y + tilt*z) * t;
+ // error definition changes for the different calls
+ we = 2. * t;
+ we *= TMath::Sqrt(cl->GetSigmaY2()+tilt*tilt*cl->GetSigmaZ2());
+ // Update sums for error calculation
+ yerr = 1./(TMath::Sqrt(cl->GetSigmaY2()) + fSysClusterError);
+ yerr *= yerr;
+ zerr = 1./cl->GetSigmaZ2();
+ for(Int_t ipol = 0; ipol < 5; ipol++){
+ fSumPolY[ipol] += yerr;
+ yerr *= x;
+ if(ipol < 3){
+ fSumPolZ[ipol] += zerr;
+ zerr *= x;
+ }
+ }
+ fTrackFitter->AddPoint(uvt, w, we);
+ fZfitter->AddPoint(&x, z, static_cast<Double_t>(TMath::Sqrt(cl->GetSigmaZ2())));
+ }
+}
+
+//_____________________________________________________________________________
+Bool_t AliTRDtrackerV1::AliTRDtrackFitterRieman::CheckAcceptable(Double_t offset, Double_t slope){
+ //
+ // Check whether z-results are acceptable
+ // Definition: Distance between tracklet fit and track fit has to be
+ // less then half a padlength
+ // Point of comparision is at the anode wire
+ //
+ Bool_t acceptablez = kTRUE;
+ Double_t zref = 0.0;
+ for (Int_t iLayer = 0; iLayer < kNPlanes; iLayer++) {
+ if(!fTracklets[iLayer]->IsOK()) continue;
+ zref = offset + slope * (fTracklets[iLayer]->GetX0() - fXref);
+ if (TMath::Abs(fTracklets[iLayer]->GetZfit(0) - zref) > fTracklets[iLayer]->GetPadLength() * 0.5 + 1.0)
+ acceptablez = kFALSE;
+ }
+ return acceptablez;
+}
+
+//_____________________________________________________________________________
+Double_t AliTRDtrackerV1::AliTRDtrackFitterRieman::GetYat(Double_t x) const {
+ //
+ // Calculate y position out of the track parameters
+ // y: R^2 = (x - x0)^2 + (y - y0)^2
+ // => y = y0 +/- Sqrt(R^2 - (x - x0)^2)
+ // R = Sqrt() = 1/Curvature
+ // => y = y0 +/- Sqrt(1/Curvature^2 - (x - x0)^2)
+ //
+ Double_t y = 0;
+ Double_t disc = (x * fParameters[0] + fParameters[1]);
+ disc = 1 - fParameters[0]*fParameters[2] + fParameters[1]*fParameters[1] - disc*disc;
+ if (disc >= 0) {
+ disc = TMath::Sqrt(disc);
+ y = (1.0 - disc) / fParameters[0];
+ }
+ return y;
+}
+
+//_____________________________________________________________________________
+Double_t AliTRDtrackerV1::AliTRDtrackFitterRieman::GetZat(Double_t x) const {
+ //
+ // Return z position for a given x position
+ // Simple linear function
+ //
+ return fParameters[3] + fParameters[4] * (x - fXref);
+}
+
+//_____________________________________________________________________________
+Double_t AliTRDtrackerV1::AliTRDtrackFitterRieman::GetDyDxAt(Double_t x) const {
+ //
+ // Calculate dydx at a given radial position out of the track parameters
+ // dy: R^2 = (x - x0)^2 + (y - y0)^2
+ // => y = +/- Sqrt(R^2 - (x - x0)^2) + y0
+ // => dy/dx = (x - x0)/Sqrt(R^2 - (x - x0)^2)
+ // Curvature: cr = 1/R = a/Sqrt(1 + b^2 - c*a)
+ // => dy/dx = (x - x0)/(1/(cr^2) - (x - x0)^2)
+ //
+ Double_t x0 = -fParameters[1] / fParameters[0];
+ Double_t curvature = GetCurvature();
+ Double_t dy = 0;
+ if (-fParameters[2] * fParameters[0] + fParameters[1] * fParameters[1] + 1 > 0) {
+ if (1.0/(curvature * curvature) - (x - x0) * (x - x0) > 0.0) {
+ Double_t yderiv = (x - x0) / TMath::Sqrt(1.0/(curvature * curvature) - (x - x0) * (x - x0));
+ if (fParameters[0] < 0) yderiv *= -1.0;
+ dy = yderiv;
+ }
+ }
+ return dy;
+}
+
+//_____________________________________________________________________________
+Double_t AliTRDtrackerV1::AliTRDtrackFitterRieman::GetCurvature() const {
+ //
+ // Calculate track curvature
+ //
+ //
+ Double_t curvature = 1.0 + fParameters[1]*fParameters[1] - fParameters[2]*fParameters[0];
+ if (curvature > 0.0)
+ curvature = fParameters[0] / TMath::Sqrt(curvature);
+ return curvature;
+}
+
+//_____________________________________________________________________________
+void AliTRDtrackerV1::AliTRDtrackFitterRieman::GetCovAt(Double_t x, Double_t *cov) const {
+ //
+ // Error Definition according to gauss error propagation
+ //
+ TMatrixD transform(3,3);
+ transform(0,0) = transform(1,1) = transform(2,2) = 1;
+ transform(0,1) = transform(1,2) = x;
+ transform(0,2) = x*x;
+ TMatrixD covariance(transform, TMatrixD::kMult, *fCovarPolY);
+ covariance *= transform.T();
+ cov[0] = covariance(0,0);
+ TMatrixD transformZ(2,2);
+ transformZ(0,0) = transformZ(1,1) = 1;
+ transformZ(0,1) = x;
+ TMatrixD covarZ(transformZ, TMatrixD::kMult, *fCovarPolZ);
+ covarZ *= transformZ.T();
+ cov[1] = covarZ(0,0);
+ cov[2] = 0;
+}
+
+//____________________________________________________________________
+Double_t AliTRDtrackerV1::AliTRDtrackFitterRieman::CalculateReferenceX(){
+ //
+ // Calculates the reference x-position for the tilted Rieman fit defined as middle
+ // of the stack (middle between layers 2 and 3). For the calculation all the tracklets
+ // are taken into account
+ //
+ // Parameters: - Array of tracklets(AliTRDseedV1)
+ //
+ // Output: - The reference x-position(Float_t)
+ //
+ Int_t nDistances = 0;
+ Float_t meanDistance = 0.;
+ Int_t startIndex = 5;
+ for(Int_t il =5; il > 0; il--){
+ if(fTracklets[il]->IsOK() && fTracklets[il -1]->IsOK()){
+ Float_t xdiff = fTracklets[il]->GetX0() - fTracklets[il -1]->GetX0();
+ meanDistance += xdiff;
+ nDistances++;
+ }
+ if(fTracklets[il]->IsOK()) startIndex = il;
+ }
+ if(fTracklets[0]->IsOK()) startIndex = 0;
+ if(!nDistances){
+ // We should normally never get here
+ Float_t xpos[2]; memset(xpos, 0, sizeof(Float_t) * 2);
+ Int_t iok = 0, idiff = 0;
+ // This attempt is worse and should be avoided:
+ // check for two chambers which are OK and repeat this without taking the mean value
+ // Strategy avoids a division by 0;
+ for(Int_t il = 5; il >= 0; il--){
+ if(fTracklets[il]->IsOK()){
+ xpos[iok] = fTracklets[il]->GetX0();
+ iok++;
+ startIndex = il;
+ }
+ if(iok) idiff++; // to get the right difference;
+ if(iok > 1) break;
+ }
+ if(iok > 1){
+ meanDistance = (xpos[0] - xpos[1])/idiff;
+ }
+ else{
+ // we have do not even have 2 layers which are OK? The we do not need to fit at all
+ return 331.;
+ }
+ }
+ else{
+ meanDistance /= nDistances;
+ }
+ return fTracklets[startIndex]->GetX0() + (2.5 - startIndex) * meanDistance - 0.5 * (AliTRDgeometry::AmThick() + AliTRDgeometry::DrThick());
+}
git://git.uio.no / u / mrichter / AliRoot.git / blobdiff