Line data Source code
1 : /**************************************************************************
2 : * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
3 : * *
4 : * Author: The ALICE Off-line Project. *
5 : * Contributors are mentioned in the code where appropriate. *
6 : * *
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 : **************************************************************************/
15 :
16 : /* $Id$ */
17 :
18 : //-----------------------------------------------------------------------------
19 : /// \class AliMUONTrackReconstructor
20 : /// MUON track reconstructor using the original method
21 : ///
22 : /// This class contains as data:
23 : /// - the parameters for the track reconstruction
24 : ///
25 : /// It contains as methods, among others:
26 : /// - MakeTracks to build the tracks
27 : //-----------------------------------------------------------------------------
28 :
29 : #include "AliMUONTrackReconstructor.h"
30 :
31 : #include "AliMUONConstants.h"
32 : #include "AliMUONVCluster.h"
33 : #include "AliMUONVClusterServer.h"
34 : #include "AliMUONVClusterStore.h"
35 : #include "AliMUONTrack.h"
36 : #include "AliMUONTrackParam.h"
37 : #include "AliMUONTrackExtrap.h"
38 : #include "AliMUONRecoParam.h"
39 : #include "AliMUONGeometryTransformer.h"
40 :
41 : #include "AliMpArea.h"
42 :
43 : #include "AliLog.h"
44 :
45 : #include <TMinuit.h>
46 : #include <Riostream.h>
47 : #include <TMath.h>
48 : #include <TMatrixD.h>
49 : #include <TClonesArray.h>
50 :
51 : // Functions to be minimized with Minuit
52 : void TrackChi2(Int_t &nParam, Double_t *gradient, Double_t &chi2, Double_t *param, Int_t flag);
53 :
54 : using std::endl;
55 : using std::cout;
56 : /// \cond CLASSIMP
57 18 : ClassImp(AliMUONTrackReconstructor) // Class implementation in ROOT context
58 : /// \endcond
59 :
60 : //__________________________________________________________________________
61 : AliMUONTrackReconstructor::AliMUONTrackReconstructor(const AliMUONRecoParam* recoParam, AliMUONVClusterServer* clusterServer,
62 : const AliMUONGeometryTransformer* transformer)
63 0 : : AliMUONVTrackReconstructor(recoParam, clusterServer, transformer)
64 0 : {
65 : /// Constructor
66 0 : }
67 :
68 : //__________________________________________________________________________
69 : AliMUONTrackReconstructor::~AliMUONTrackReconstructor()
70 0 : {
71 : /// Destructor
72 0 : }
73 :
74 : //__________________________________________________________________________
75 : Bool_t AliMUONTrackReconstructor::MakeTrackCandidates(AliMUONVClusterStore& clusterStore)
76 : {
77 : /// To make track candidates (assuming linear propagation if the flag fgkMakeTrackCandidatesFast is set to kTRUE):
78 : /// Start with segments station(1..) 4 or 5 then follow track in station 5 or 4.
79 : /// Good candidates are made of at least three clusters.
80 : /// Keep only best candidates or all of them according to the flag fgkTrackAllTracks.
81 :
82 : TClonesArray *segments;
83 : AliMUONTrack *track;
84 : Int_t iCandidate = 0;
85 : Bool_t clusterFound;
86 :
87 0 : AliDebug(1,"Enter MakeTrackCandidates");
88 :
89 : // Unless we're doing combined tracking, we'll clusterize all stations at once
90 : Int_t firstChamber(0);
91 : Int_t lastChamber(9);
92 :
93 0 : if (GetRecoParam()->CombineClusterTrackReco()) {
94 : // ... Here's the exception : ask the clustering to reconstruct
95 : // clusters *only* in station 4 and 5 for combined tracking
96 : firstChamber = 6;
97 0 : }
98 :
99 0 : for (Int_t i = firstChamber; i <= lastChamber; ++i )
100 : {
101 0 : if (fClusterServer && GetRecoParam()->UseChamber(i)) fClusterServer->Clusterize(i, clusterStore, AliMpArea(), GetRecoParam());
102 : }
103 :
104 : // Loop over stations(1..) 5 and 4 and make track candidates
105 0 : for (Int_t istat=4; istat>=3; istat--) {
106 :
107 : // Make segments in the station
108 0 : segments = MakeSegmentsBetweenChambers(clusterStore, 2*istat, 2*istat+1);
109 :
110 : // Loop over segments
111 0 : for (Int_t iseg=0; iseg<segments->GetEntriesFast(); iseg++)
112 : {
113 0 : AliDebug(1,Form("Making primary candidate(1..) %d",++iCandidate));
114 :
115 : // Transform segments to tracks and put them at the end of fRecTracksPtr
116 0 : track = new ((*fRecTracksPtr)[fRecTracksPtr->GetLast()+1]) AliMUONTrack((AliMUONObjectPair*)((*segments)[iseg]),GetRecoParam()->GetBendingVertexDispersion());
117 0 : fNRecTracks++;
118 :
119 : // Look for compatible cluster(s) in the other station
120 0 : if (GetRecoParam()->MakeTrackCandidatesFast())
121 0 : clusterFound = FollowLinearTrackInStation(*track, clusterStore, 7-istat);
122 0 : else clusterFound = FollowTrackInStation(*track, clusterStore, 7-istat);
123 :
124 : // Remove track if no cluster found on a requested station
125 : // or abort tracking if there are too many candidates
126 0 : if (GetRecoParam()->RequestStation(7-istat)) {
127 0 : if (!clusterFound) {
128 0 : fRecTracksPtr->Remove(track);
129 0 : fNRecTracks--;
130 0 : } else if (fNRecTracks > GetRecoParam()->GetMaxTrackCandidates()) {
131 0 : AliError(Form("Too many track candidates (%d tracks). Stop tracking.", fNRecTracks));
132 0 : return kFALSE;
133 : }
134 : } else {
135 0 : if ((fNRecTracks + segments->GetEntriesFast() - iseg - 1) > GetRecoParam()->GetMaxTrackCandidates()) {
136 0 : AliError(Form("Too many track candidates (%d tracks). Stop tracking.", fNRecTracks + segments->GetEntriesFast() - iseg - 1));
137 0 : return kFALSE;
138 : }
139 : }
140 :
141 : }
142 :
143 : }
144 :
145 : // Keep all different tracks or only the best ones as required
146 0 : if (GetRecoParam()->TrackAllTracks()) RemoveIdenticalTracks();
147 0 : else RemoveDoubleTracks();
148 :
149 0 : AliDebug(1,Form("Number of good candidates = %d",fNRecTracks));
150 :
151 0 : return kTRUE;
152 :
153 0 : }
154 :
155 : //__________________________________________________________________________
156 : Bool_t AliMUONTrackReconstructor::MakeMoreTrackCandidates(AliMUONVClusterStore& clusterStore)
157 : {
158 : /// To make extra track candidates (assuming linear propagation if the flag fgkMakeTrackCandidatesFast is set to kTRUE):
159 : /// clustering is supposed to be already done
160 : /// Start with segments made of 1 cluster in each of the stations 4 and 5 then follow track in remaining chambers.
161 : /// Good candidates are made of at least three clusters if both station are requested (two otherwise).
162 : /// Keep only best candidates or all of them according to the flag fgkTrackAllTracks.
163 :
164 : TClonesArray *segments;
165 : AliMUONObjectPair *segment;
166 : AliMUONTrack *track;
167 : Int_t iCandidate = 0, iCurrentTrack, nCurrentTracks;
168 : Bool_t clusterFound;
169 :
170 0 : AliDebug(1,"Enter MakeMoreTrackCandidates");
171 :
172 : // Double loop over chambers in stations(1..) 4 and 5 to make track candidates
173 0 : for (Int_t ich1 = 6; ich1 <= 7; ich1++) {
174 0 : for (Int_t ich2 = 8; ich2 <= 9; ich2++) {
175 :
176 : // Make segments in the station
177 0 : segments = MakeSegmentsBetweenChambers(clusterStore, ich1, ich2);
178 :
179 : /// Remove segments already attached to a track
180 0 : RemoveUsedSegments(*segments);
181 :
182 : // Loop over segments
183 0 : for (Int_t iSegment=0; iSegment<segments->GetEntriesFast(); iSegment++)
184 : {
185 0 : AliDebug(1,Form("Making primary candidate(1..) %d",++iCandidate));
186 0 : segment = (AliMUONObjectPair*) segments->UncheckedAt(iSegment);
187 :
188 : // Transform segments to tracks and put them at the end of fRecTracksPtr
189 0 : iCurrentTrack = fRecTracksPtr->GetLast()+1;
190 0 : track = new ((*fRecTracksPtr)[iCurrentTrack]) AliMUONTrack(segment,GetRecoParam()->GetBendingVertexDispersion());
191 0 : fNRecTracks++;
192 :
193 : // Look for compatible cluster(s) in the second chamber of station 5
194 0 : clusterFound = FollowLinearTrackInChamber(*track, clusterStore, 17-ich2);
195 :
196 : // skip the original track in case it has been removed
197 0 : if (GetRecoParam()->TrackAllTracks() && clusterFound) iCurrentTrack++;
198 :
199 : // loop over every new tracks
200 0 : nCurrentTracks = fRecTracksPtr->GetLast()+1;
201 0 : while (iCurrentTrack < nCurrentTracks) {
202 0 : track = (AliMUONTrack*) fRecTracksPtr->UncheckedAt(iCurrentTrack);
203 :
204 : // Look for compatible cluster(s) in the second chamber of station 4
205 0 : FollowLinearTrackInChamber(*track, clusterStore, 13-ich1);
206 :
207 0 : iCurrentTrack++;
208 : }
209 :
210 : // abort tracking if there are too many candidates
211 0 : if ((fNRecTracks + segments->GetEntriesFast() - iSegment - 1) > GetRecoParam()->GetMaxTrackCandidates()) {
212 0 : AliError(Form("Too many track candidates (%d tracks). Stop tracking.", fNRecTracks + segments->GetEntriesFast() - iSegment - 1));
213 0 : return kFALSE;
214 : }
215 :
216 : }
217 :
218 : }
219 : }
220 :
221 : // Keep only the best tracks if required
222 0 : if (!GetRecoParam()->TrackAllTracks()) RemoveDoubleTracks();
223 0 : else fRecTracksPtr->Compress();
224 :
225 0 : AliDebug(1,Form("Number of good candidates = %d",fNRecTracks));
226 :
227 0 : return kTRUE;
228 :
229 0 : }
230 :
231 : //__________________________________________________________________________
232 : Bool_t AliMUONTrackReconstructor::FollowTracks(AliMUONVClusterStore& clusterStore)
233 : {
234 : /// Follow tracks in stations(1..) 3, 2 and 1
235 0 : AliDebug(1,"Enter FollowTracks");
236 :
237 : AliMUONTrack *track, *nextTrack;
238 : AliMUONTrackParam *trackParam, *nextTrackParam;
239 : Int_t currentNRecTracks;
240 :
241 0 : Double_t sigmaCut2 = GetRecoParam()->GetSigmaCutForTracking() *
242 0 : GetRecoParam()->GetSigmaCutForTracking();
243 :
244 0 : for (Int_t station = 2; station >= 0; station--) {
245 :
246 : // Save the actual number of reconstructed track in case of
247 : // tracks are added or suppressed during the tracking procedure
248 : // !! Do not compress fRecTracksPtr until the end of the loop over tracks !!
249 0 : currentNRecTracks = fNRecTracks;
250 :
251 0 : for (Int_t iRecTrack = 0; iRecTrack <currentNRecTracks; iRecTrack++) {
252 0 : AliDebug(1,Form("FollowTracks: track candidate(1..) %d", iRecTrack+1));
253 :
254 0 : track = (AliMUONTrack*) fRecTracksPtr->UncheckedAt(iRecTrack);
255 :
256 : // Fit the track:
257 : // Do not take into account the multiple scattering to speed up the fit
258 : // Calculate the track parameter covariance matrix
259 : // If there is no cluster out of station 4 or 5 then use the vertex to better constrain the fit
260 0 : if (((AliMUONTrackParam*) track->GetTrackParamAtCluster()->First())->GetClusterPtr()->GetChamberId() > 5)
261 0 : Fit(*track, kFALSE, kTRUE, kTRUE);
262 0 : else Fit(*track, kFALSE, kFALSE, kTRUE);
263 :
264 : // remove tracks out of limits
265 0 : if (!IsAcceptable(*((AliMUONTrackParam*)track->GetTrackParamAtCluster()->First()))) {
266 0 : fRecTracksPtr->Remove(track);
267 0 : fNRecTracks--;
268 0 : continue;
269 : }
270 :
271 : // remove track if the normalized chi2 is too high
272 0 : if (track->GetNormalizedChi2() > sigmaCut2) {
273 0 : fRecTracksPtr->Remove(track);
274 0 : fNRecTracks--;
275 0 : continue;
276 : }
277 :
278 : // save parameters from fit into smoothed parameters to complete track afterward
279 0 : if (GetRecoParam()->ComplementTracks()) {
280 :
281 0 : if (station==2) { // save track parameters on stations 4 and 5
282 :
283 : // extrapolate track parameters and covariances at each cluster
284 : // remove the track in case of failure
285 0 : if (!track->UpdateCovTrackParamAtCluster()) {
286 0 : fRecTracksPtr->Remove(track);
287 0 : fNRecTracks--;
288 0 : continue;
289 : }
290 :
291 : // save them
292 0 : trackParam = (AliMUONTrackParam*) track->GetTrackParamAtCluster()->First();
293 0 : while (trackParam) {
294 0 : trackParam->SetSmoothParameters(trackParam->GetParameters());
295 0 : trackParam->SetSmoothCovariances(trackParam->GetCovariances());
296 0 : trackParam = (AliMUONTrackParam*) track->GetTrackParamAtCluster()->After(trackParam);
297 : }
298 :
299 : } else { // or save track parameters on last station only
300 :
301 0 : trackParam = (AliMUONTrackParam*) track->GetTrackParamAtCluster()->First();
302 0 : if (trackParam->GetClusterPtr()->GetChamberId() < 2*(station+2)) {
303 :
304 : // save parameters from fit
305 0 : trackParam->SetSmoothParameters(trackParam->GetParameters());
306 0 : trackParam->SetSmoothCovariances(trackParam->GetCovariances());
307 :
308 : // save parameters extrapolated to the second chamber of the same station if it has been hit
309 0 : nextTrackParam = (AliMUONTrackParam*) track->GetTrackParamAtCluster()->After(trackParam);
310 0 : if (nextTrackParam->GetClusterPtr()->GetChamberId() < 2*(station+2)) {
311 :
312 : // reset parameters and covariances
313 0 : nextTrackParam->SetParameters(trackParam->GetParameters());
314 0 : nextTrackParam->SetZ(trackParam->GetZ());
315 0 : nextTrackParam->SetCovariances(trackParam->GetCovariances());
316 :
317 : // extrapolate them to the z of the corresponding cluster
318 : // remove the track in case of failure
319 0 : if (!AliMUONTrackExtrap::ExtrapToZCov(nextTrackParam, nextTrackParam->GetClusterPtr()->GetZ())) {
320 0 : fRecTracksPtr->Remove(track);
321 0 : fNRecTracks--;
322 0 : continue;
323 : }
324 :
325 : // save them
326 0 : nextTrackParam->SetSmoothParameters(nextTrackParam->GetParameters());
327 0 : nextTrackParam->SetSmoothCovariances(nextTrackParam->GetCovariances());
328 :
329 0 : }
330 :
331 : }
332 :
333 : }
334 :
335 : }
336 :
337 : // Look for compatible cluster(s) in station(0..) "station"
338 0 : if (!FollowTrackInStation(*track, clusterStore, station)) {
339 :
340 : // Try to recover track if required
341 0 : if (GetRecoParam()->RecoverTracks()) {
342 :
343 : // work on a copy of the track if this station is not required
344 : // to keep the case where no cluster is reconstructed as a possible candidate
345 0 : if (!GetRecoParam()->RequestStation(station)) {
346 0 : track = new ((*fRecTracksPtr)[fRecTracksPtr->GetLast()+1]) AliMUONTrack(*track);
347 0 : fNRecTracks++;
348 0 : }
349 :
350 : // try to recover
351 0 : if (!RecoverTrack(*track, clusterStore, station)) {
352 : // remove track if no cluster found
353 0 : fRecTracksPtr->Remove(track);
354 0 : fNRecTracks--;
355 0 : }
356 :
357 0 : } else if (GetRecoParam()->RequestStation(station)) {
358 : // remove track if no cluster found
359 0 : fRecTracksPtr->Remove(track);
360 0 : fNRecTracks--;
361 0 : }
362 :
363 : }
364 :
365 : // abort tracking if there are too many candidates
366 0 : if (fNRecTracks > GetRecoParam()->GetMaxTrackCandidates()) {
367 0 : AliError(Form("Too many track candidates (%d tracks). Stop tracking.", fNRecTracks));
368 0 : return kFALSE;
369 : }
370 :
371 : }
372 :
373 : // Compress fRecTracksPtr for the next step
374 0 : fRecTracksPtr->Compress();
375 :
376 : // Keep only the best tracks if required
377 0 : if (!GetRecoParam()->TrackAllTracks()) RemoveDoubleTracks();
378 :
379 : }
380 :
381 : // Last fit of track candidates with all stations
382 : // Take into account the multiple scattering and remove bad tracks
383 : Int_t trackIndex = -1;
384 0 : track = (AliMUONTrack*) fRecTracksPtr->First();
385 0 : while (track) {
386 :
387 0 : trackIndex++;
388 0 : nextTrack = (AliMUONTrack*) fRecTracksPtr->After(track); // prepare next track
389 :
390 0 : Fit(*track, kTRUE, kFALSE, kTRUE);
391 :
392 : // Printout for debuging
393 0 : if (AliLog::GetGlobalDebugLevel() >= 3) {
394 0 : cout << "FollowTracks: track candidate(0..) " << trackIndex << " after final fit" << endl;
395 0 : track->RecursiveDump();
396 0 : }
397 :
398 : // Remove the track if the normalized chi2 is too high
399 0 : if (track->GetNormalizedChi2() > sigmaCut2) {
400 0 : fRecTracksPtr->Remove(track);
401 0 : fNRecTracks--;
402 : track = nextTrack;
403 0 : continue;
404 : }
405 :
406 : // save parameters from fit into smoothed parameters to complete track afterward
407 0 : if (GetRecoParam()->ComplementTracks()) {
408 :
409 0 : trackParam = (AliMUONTrackParam*) track->GetTrackParamAtCluster()->First();
410 0 : if (trackParam->GetClusterPtr()->GetChamberId() < 2) {
411 :
412 : // save parameters from fit
413 0 : trackParam->SetSmoothParameters(trackParam->GetParameters());
414 0 : trackParam->SetSmoothCovariances(trackParam->GetCovariances());
415 :
416 : // save parameters extrapolated to the second chamber of the same station if it has been hit
417 0 : nextTrackParam = (AliMUONTrackParam*) track->GetTrackParamAtCluster()->After(trackParam);
418 0 : if (nextTrackParam->GetClusterPtr()->GetChamberId() < 2) {
419 :
420 : // reset parameters and covariances
421 0 : nextTrackParam->SetParameters(trackParam->GetParameters());
422 0 : nextTrackParam->SetZ(trackParam->GetZ());
423 0 : nextTrackParam->SetCovariances(trackParam->GetCovariances());
424 :
425 : // extrapolate them to the z of the corresponding cluster
426 : // remove the track in case of failure
427 0 : if (!AliMUONTrackExtrap::ExtrapToZCov(nextTrackParam, nextTrackParam->GetClusterPtr()->GetZ())) {
428 0 : fRecTracksPtr->Remove(track);
429 0 : fNRecTracks--;
430 : track = nextTrack;
431 0 : continue;
432 : }
433 :
434 : // save them
435 0 : nextTrackParam->SetSmoothParameters(nextTrackParam->GetParameters());
436 0 : nextTrackParam->SetSmoothCovariances(nextTrackParam->GetCovariances());
437 :
438 0 : }
439 :
440 : }
441 :
442 : }
443 :
444 : track = nextTrack;
445 :
446 : }
447 :
448 0 : fRecTracksPtr->Compress();
449 :
450 : return kTRUE;
451 :
452 0 : }
453 :
454 : //__________________________________________________________________________
455 : Bool_t AliMUONTrackReconstructor::FollowTrackInChamber(AliMUONTrack &trackCandidate, AliMUONVClusterStore& clusterStore, Int_t nextChamber)
456 : {
457 : /// Follow trackCandidate in chamber(0..) nextChamber and search for compatible cluster(s)
458 : /// Keep all possibilities or only the best one(s) according to the flag fgkTrackAllTracks:
459 : /// kTRUE: duplicate "trackCandidate" if there are several possibilities and add the new tracks at the end of
460 : /// fRecTracksPtr to avoid conficts with other track candidates at this current stage of the tracking procedure.
461 : /// Remove the obsolete "trackCandidate" at the end.
462 : /// kFALSE: add only the best cluster(s) to the "trackCandidate". Try to add a couple of clusters in priority.
463 0 : AliDebug(1,Form("Enter FollowTrackInChamber(1..) %d", nextChamber+1));
464 :
465 0 : Double_t chi2WithOneCluster = AliMUONTrack::MaxChi2();
466 0 : Double_t maxChi2WithOneCluster = 2. * GetRecoParam()->GetSigmaCutForTracking() *
467 0 : GetRecoParam()->GetSigmaCutForTracking(); // 2 because 2 quantities in chi2
468 : Double_t bestChi2WithOneCluster = maxChi2WithOneCluster;
469 : Bool_t foundOneCluster = kFALSE;
470 : AliMUONTrack *newTrack = 0x0;
471 : AliMUONVCluster *cluster;
472 0 : AliMUONTrackParam extrapTrackParam;
473 0 : AliMUONTrackParam extrapTrackParamAtCh;
474 0 : AliMUONTrackParam extrapTrackParamAtCluster;
475 0 : AliMUONTrackParam bestTrackParamAtCluster;
476 :
477 : // Get track parameters according to the propagation direction
478 0 : if (nextChamber > 7) extrapTrackParamAtCh = *(AliMUONTrackParam*)trackCandidate.GetTrackParamAtCluster()->Last();
479 0 : else extrapTrackParamAtCh = *(AliMUONTrackParam*)trackCandidate.GetTrackParamAtCluster()->First();
480 :
481 : // Printout for debuging
482 0 : if ((AliLog::GetDebugLevel("MUON","AliMUONTrackReconstructor") >= 2) || (AliLog::GetGlobalDebugLevel() >= 2)) {
483 0 : cout<<endl<<"Track parameters and covariances at first cluster:"<<endl;
484 0 : extrapTrackParamAtCh.GetParameters().Print();
485 0 : extrapTrackParamAtCh.GetCovariances().Print();
486 : }
487 :
488 : // Add MCS effect
489 0 : Int_t currentChamber = extrapTrackParamAtCh.GetClusterPtr()->GetChamberId();
490 0 : AliMUONTrackExtrap::AddMCSEffect(&extrapTrackParamAtCh,AliMUONConstants::ChamberThicknessInX0(currentChamber),-1.);
491 :
492 : // Add MCS in the missing chamber(s) if any
493 0 : while (currentChamber > nextChamber + 1) {
494 : // extrapolation to the missing chamber
495 0 : currentChamber--;
496 0 : if (!AliMUONTrackExtrap::ExtrapToZCov(&extrapTrackParamAtCh, AliMUONConstants::DefaultChamberZ(currentChamber))) return kFALSE;
497 : // add MCS effect
498 0 : AliMUONTrackExtrap::AddMCSEffect(&extrapTrackParamAtCh,AliMUONConstants::ChamberThicknessInX0(currentChamber),-1.);
499 : }
500 :
501 : //Extrapolate trackCandidate to chamber
502 0 : if (!AliMUONTrackExtrap::ExtrapToZCov(&extrapTrackParamAtCh, AliMUONConstants::DefaultChamberZ(nextChamber))) return kFALSE;
503 :
504 : // Printout for debuging
505 0 : if ((AliLog::GetDebugLevel("MUON","AliMUONTrackReconstructor") >= 2) || (AliLog::GetGlobalDebugLevel() >= 2)) {
506 0 : cout<<endl<<"Track parameters and covariances at first cluster extrapolated to z = "<<AliMUONConstants::DefaultChamberZ(nextChamber)<<":"<<endl;
507 0 : extrapTrackParamAtCh.GetParameters().Print();
508 0 : extrapTrackParamAtCh.GetCovariances().Print();
509 : }
510 :
511 : // Printout for debuging
512 0 : if ((AliLog::GetDebugLevel("MUON","AliMUONTrackReconstructor") >= 1) || (AliLog::GetGlobalDebugLevel() >= 1)) {
513 0 : cout << "FollowTrackInStation: look for clusters in chamber(1..): " << nextChamber+1 << endl;
514 : }
515 :
516 : // Ask the clustering to reconstruct new clusters around the track position in the current chamber
517 : // except for station 4 and 5 that are already entirely clusterized
518 0 : if (GetRecoParam()->CombineClusterTrackReco()) {
519 0 : if (nextChamber < 6) AskForNewClustersInChamber(extrapTrackParamAtCh, clusterStore, nextChamber);
520 : }
521 :
522 : // Create iterators to loop over clusters in both chambers
523 0 : TIter next(clusterStore.CreateChamberIterator(nextChamber,nextChamber));
524 :
525 : // look for cluster in chamber
526 0 : while ( ( cluster = static_cast<AliMUONVCluster*>(next()) ) ) {
527 :
528 : // try to add the current cluster fast
529 0 : if (!TryOneClusterFast(extrapTrackParamAtCh, cluster)) continue;
530 :
531 : // try to add the current cluster accuratly
532 0 : chi2WithOneCluster = TryOneCluster(extrapTrackParamAtCh, cluster, extrapTrackParamAtCluster);
533 :
534 : // if good chi2 then consider to add cluster
535 0 : if (chi2WithOneCluster < maxChi2WithOneCluster) {
536 : foundOneCluster = kTRUE;
537 :
538 : // Printout for debuging
539 0 : if ((AliLog::GetDebugLevel("MUON","AliMUONTrackReconstructor") >= 1) || (AliLog::GetGlobalDebugLevel() >= 1)) {
540 0 : cout << "FollowTrackInStation: found one cluster in chamber(1..): " << nextChamber+1
541 0 : << " (Chi2 = " << chi2WithOneCluster << ")" << endl;
542 0 : cluster->Print();
543 : }
544 :
545 0 : if (GetRecoParam()->TrackAllTracks()) {
546 : // copy trackCandidate into a new track put at the end of fRecTracksPtr and add the new cluster
547 0 : newTrack = new ((*fRecTracksPtr)[fRecTracksPtr->GetLast()+1]) AliMUONTrack(trackCandidate);
548 0 : UpdateTrack(*newTrack,extrapTrackParamAtCluster);
549 0 : fNRecTracks++;
550 :
551 : // Printout for debuging
552 0 : if ((AliLog::GetDebugLevel("MUON","AliMUONTrackReconstructor") >= 1) || (AliLog::GetGlobalDebugLevel() >= 1)) {
553 0 : cout << "FollowTrackInStation: added one cluster in chamber(1..): " << nextChamber+1 << endl;
554 0 : if (AliLog::GetGlobalDebugLevel() >= 3) newTrack->RecursiveDump();
555 : }
556 :
557 0 : } else if (chi2WithOneCluster < bestChi2WithOneCluster) {
558 : // keep track of the best single cluster except if a couple of clusters has already been found
559 : bestChi2WithOneCluster = chi2WithOneCluster;
560 0 : bestTrackParamAtCluster = extrapTrackParamAtCluster;
561 : }
562 :
563 : }
564 :
565 : }
566 :
567 : // fill out the best track if required else clean up the fRecTracksPtr array
568 0 : if (!GetRecoParam()->TrackAllTracks()) {
569 0 : if (foundOneCluster) {
570 0 : UpdateTrack(trackCandidate,bestTrackParamAtCluster);
571 :
572 : // Printout for debuging
573 0 : if ((AliLog::GetDebugLevel("MUON","AliMUONTrackReconstructor") >= 1) || (AliLog::GetGlobalDebugLevel() >= 1)) {
574 0 : cout << "FollowTrackInStation: added the best cluster in chamber(1..): " << bestTrackParamAtCluster.GetClusterPtr()->GetChamberId()+1 << endl;
575 0 : if (AliLog::GetGlobalDebugLevel() >= 3) trackCandidate.RecursiveDump();
576 : }
577 :
578 0 : } else return kFALSE;
579 :
580 0 : } else if (foundOneCluster) {
581 :
582 : // remove obsolete track
583 0 : fRecTracksPtr->Remove(&trackCandidate);
584 0 : fNRecTracks--;
585 :
586 0 : } else return kFALSE;
587 :
588 0 : return kTRUE;
589 :
590 0 : }
591 :
592 : //__________________________________________________________________________
593 : Bool_t AliMUONTrackReconstructor::FollowTrackInStation(AliMUONTrack &trackCandidate, AliMUONVClusterStore& clusterStore, Int_t nextStation)
594 : {
595 : /// Follow trackCandidate in station(0..) nextStation and search for compatible cluster(s)
596 : /// Keep all possibilities or only the best one(s) according to the flag fgkTrackAllTracks:
597 : /// kTRUE: duplicate "trackCandidate" if there are several possibilities and add the new tracks at the end of
598 : /// fRecTracksPtr to avoid conficts with other track candidates at this current stage of the tracking procedure.
599 : /// Remove the obsolete "trackCandidate" at the end.
600 : /// kFALSE: add only the best cluster(s) to the "trackCandidate". Try to add a couple of clusters in priority.
601 0 : AliDebug(1,Form("Enter FollowTrackInStation(1..) %d", nextStation+1));
602 :
603 : // Order the chamber according to the propagation direction (tracking starts with chamber 2):
604 : // - nextStation == station(1...) 5 => forward propagation
605 : // - nextStation < station(1...) 5 => backward propagation
606 : Int_t ch1, ch2;
607 0 : if (nextStation==4) {
608 0 : ch1 = 2*nextStation+1;
609 : ch2 = 2*nextStation;
610 0 : } else {
611 : ch1 = 2*nextStation;
612 0 : ch2 = 2*nextStation+1;
613 : }
614 :
615 0 : Double_t chi2WithOneCluster = AliMUONTrack::MaxChi2();
616 0 : Double_t chi2WithTwoClusters = AliMUONTrack::MaxChi2();
617 0 : Double_t maxChi2WithOneCluster = 2. * GetRecoParam()->GetSigmaCutForTracking() *
618 0 : GetRecoParam()->GetSigmaCutForTracking(); // 2 because 2 quantities in chi2
619 0 : Double_t maxChi2WithTwoClusters = 4. * GetRecoParam()->GetSigmaCutForTracking() *
620 0 : GetRecoParam()->GetSigmaCutForTracking(); // 4 because 4 quantities in chi2
621 : Double_t bestChi2WithOneCluster = maxChi2WithOneCluster;
622 : Double_t bestChi2WithTwoClusters = maxChi2WithTwoClusters;
623 : Bool_t foundOneCluster = kFALSE;
624 : Bool_t foundTwoClusters = kFALSE;
625 : AliMUONTrack *newTrack = 0x0;
626 : AliMUONVCluster *clusterCh1, *clusterCh2;
627 0 : AliMUONTrackParam extrapTrackParam;
628 0 : AliMUONTrackParam extrapTrackParamAtCh;
629 0 : AliMUONTrackParam extrapTrackParamAtCluster1;
630 0 : AliMUONTrackParam extrapTrackParamAtCluster2;
631 0 : AliMUONTrackParam bestTrackParamAtCluster1;
632 0 : AliMUONTrackParam bestTrackParamAtCluster2;
633 :
634 : // Get track parameters according to the propagation direction
635 0 : if (nextStation==4) extrapTrackParamAtCh = *(AliMUONTrackParam*)trackCandidate.GetTrackParamAtCluster()->Last();
636 0 : else extrapTrackParamAtCh = *(AliMUONTrackParam*)trackCandidate.GetTrackParamAtCluster()->First();
637 :
638 : // Printout for debuging
639 0 : if ((AliLog::GetDebugLevel("MUON","AliMUONTrackReconstructor") >= 2) || (AliLog::GetGlobalDebugLevel() >= 2)) {
640 0 : cout<<endl<<"Track parameters and covariances at first cluster:"<<endl;
641 0 : extrapTrackParamAtCh.GetParameters().Print();
642 0 : extrapTrackParamAtCh.GetCovariances().Print();
643 : }
644 :
645 : // Add MCS effect
646 0 : Int_t currentChamber = extrapTrackParamAtCh.GetClusterPtr()->GetChamberId();
647 0 : AliMUONTrackExtrap::AddMCSEffect(&extrapTrackParamAtCh,AliMUONConstants::ChamberThicknessInX0(currentChamber),-1.);
648 :
649 : // Add MCS in the missing chamber(s) if any
650 0 : while (ch1 < ch2 && currentChamber > ch2 + 1) {
651 : // extrapolation to the missing chamber
652 0 : currentChamber--;
653 0 : if (!AliMUONTrackExtrap::ExtrapToZCov(&extrapTrackParamAtCh, AliMUONConstants::DefaultChamberZ(currentChamber))) return kFALSE;
654 : // add MCS effect
655 0 : AliMUONTrackExtrap::AddMCSEffect(&extrapTrackParamAtCh,AliMUONConstants::ChamberThicknessInX0(currentChamber),-1.);
656 : }
657 :
658 : //Extrapolate trackCandidate to chamber "ch2"
659 0 : if (!AliMUONTrackExtrap::ExtrapToZCov(&extrapTrackParamAtCh, AliMUONConstants::DefaultChamberZ(ch2))) return kFALSE;
660 :
661 : // Printout for debuging
662 0 : if ((AliLog::GetDebugLevel("MUON","AliMUONTrackReconstructor") >= 2) || (AliLog::GetGlobalDebugLevel() >= 2)) {
663 0 : cout<<endl<<"Track parameters and covariances at first cluster extrapolated to z = "<<AliMUONConstants::DefaultChamberZ(ch2)<<":"<<endl;
664 0 : extrapTrackParamAtCh.GetParameters().Print();
665 0 : extrapTrackParamAtCh.GetCovariances().Print();
666 : }
667 :
668 : // Printout for debuging
669 0 : if ((AliLog::GetDebugLevel("MUON","AliMUONTrackReconstructor") >= 1) || (AliLog::GetGlobalDebugLevel() >= 1)) {
670 0 : cout << "FollowTrackInStation: look for clusters in chamber(1..): " << ch2+1 << endl;
671 : }
672 :
673 : // Ask the clustering to reconstruct new clusters around the track position in the current station
674 : // except for station 4 and 5 that are already entirely clusterized
675 0 : if (GetRecoParam()->CombineClusterTrackReco()) {
676 0 : if (nextStation < 3) AskForNewClustersInStation(extrapTrackParamAtCh, clusterStore, nextStation);
677 : }
678 :
679 0 : Int_t nClusters = clusterStore.GetSize();
680 0 : Bool_t *clusterCh1Used = new Bool_t[nClusters];
681 0 : for (Int_t i = 0; i < nClusters; i++) clusterCh1Used[i] = kFALSE;
682 : Int_t iCluster1;
683 :
684 : // Create iterators to loop over clusters in both chambers
685 0 : TIter nextInCh1(clusterStore.CreateChamberIterator(ch1,ch1));
686 0 : TIter nextInCh2(clusterStore.CreateChamberIterator(ch2,ch2));
687 :
688 : // look for candidates in chamber 2
689 0 : while ( ( clusterCh2 = static_cast<AliMUONVCluster*>(nextInCh2()) ) ) {
690 :
691 : // try to add the current cluster fast
692 0 : if (!TryOneClusterFast(extrapTrackParamAtCh, clusterCh2)) continue;
693 :
694 : // try to add the current cluster accuratly
695 0 : chi2WithOneCluster = TryOneCluster(extrapTrackParamAtCh, clusterCh2, extrapTrackParamAtCluster2);
696 :
697 : // if good chi2 then try to attach a cluster in the other chamber too
698 0 : if (chi2WithOneCluster < maxChi2WithOneCluster) {
699 : Bool_t foundSecondCluster = kFALSE;
700 :
701 : // Printout for debuging
702 0 : if ((AliLog::GetDebugLevel("MUON","AliMUONTrackReconstructor") >= 1) || (AliLog::GetGlobalDebugLevel() >= 1)) {
703 0 : cout << "FollowTrackInStation: found one cluster in chamber(1..): " << ch2+1
704 0 : << " (Chi2 = " << chi2WithOneCluster << ")" << endl;
705 0 : clusterCh2->Print();
706 0 : cout << " look for second clusters in chamber(1..): " << ch1+1 << " ..." << endl;
707 : }
708 :
709 : // add MCS effect for next step
710 0 : AliMUONTrackExtrap::AddMCSEffect(&extrapTrackParamAtCluster2,AliMUONConstants::ChamberThicknessInX0(ch2),-1.);
711 :
712 : // copy new track parameters for next step
713 0 : extrapTrackParam = extrapTrackParamAtCluster2;
714 :
715 : //Extrapolate track parameters to chamber "ch1"
716 0 : Bool_t normalExtrap = AliMUONTrackExtrap::ExtrapToZ(&extrapTrackParam, AliMUONConstants::DefaultChamberZ(ch1));
717 :
718 : // reset cluster iterator of chamber 1
719 0 : nextInCh1.Reset();
720 : iCluster1 = -1;
721 :
722 : // look for second candidates in chamber 1
723 0 : if (normalExtrap) while ( ( clusterCh1 = static_cast<AliMUONVCluster*>(nextInCh1()) ) ) {
724 0 : iCluster1++;
725 :
726 : // try to add the current cluster fast
727 0 : if (!TryOneClusterFast(extrapTrackParam, clusterCh1)) continue;
728 :
729 : // try to add the current cluster accurately
730 0 : chi2WithTwoClusters = TryTwoClusters(extrapTrackParamAtCluster2, clusterCh1, extrapTrackParamAtCluster1);
731 :
732 : // if good chi2 then create a new track by adding the 2 clusters to the "trackCandidate"
733 0 : if (chi2WithTwoClusters < maxChi2WithTwoClusters) {
734 : foundSecondCluster = kTRUE;
735 : foundTwoClusters = kTRUE;
736 :
737 : // Printout for debuging
738 0 : if ((AliLog::GetDebugLevel("MUON","AliMUONTrackReconstructor") >= 1) || (AliLog::GetGlobalDebugLevel() >= 1)) {
739 0 : cout << "FollowTrackInStation: found second cluster in chamber(1..): " << ch1+1
740 0 : << " (Global Chi2 = " << chi2WithTwoClusters << ")" << endl;
741 0 : clusterCh1->Print();
742 : }
743 :
744 0 : if (GetRecoParam()->TrackAllTracks()) {
745 : // copy trackCandidate into a new track put at the end of fRecTracksPtr and add the new clusters
746 0 : newTrack = new ((*fRecTracksPtr)[fRecTracksPtr->GetLast()+1]) AliMUONTrack(trackCandidate);
747 0 : UpdateTrack(*newTrack,extrapTrackParamAtCluster1,extrapTrackParamAtCluster2);
748 0 : fNRecTracks++;
749 :
750 : // Tag clusterCh1 as used
751 0 : clusterCh1Used[iCluster1] = kTRUE;
752 :
753 : // Printout for debuging
754 0 : if ((AliLog::GetDebugLevel("MUON","AliMUONTrackReconstructor") >= 1) || (AliLog::GetGlobalDebugLevel() >= 1)) {
755 0 : cout << "FollowTrackInStation: added two clusters in station(1..): " << nextStation+1 << endl;
756 0 : if (AliLog::GetGlobalDebugLevel() >= 3) newTrack->RecursiveDump();
757 : }
758 :
759 0 : } else if (chi2WithTwoClusters < bestChi2WithTwoClusters) {
760 : // keep track of the best couple of clusters
761 : bestChi2WithTwoClusters = chi2WithTwoClusters;
762 0 : bestTrackParamAtCluster1 = extrapTrackParamAtCluster1;
763 0 : bestTrackParamAtCluster2 = extrapTrackParamAtCluster2;
764 : }
765 :
766 : }
767 :
768 : }
769 :
770 : // if no clusterCh1 found then consider to add clusterCh2 only
771 0 : if (!foundSecondCluster) {
772 : foundOneCluster = kTRUE;
773 :
774 0 : if (GetRecoParam()->TrackAllTracks()) {
775 : // copy trackCandidate into a new track put at the end of fRecTracksPtr and add the new cluster
776 0 : newTrack = new ((*fRecTracksPtr)[fRecTracksPtr->GetLast()+1]) AliMUONTrack(trackCandidate);
777 0 : UpdateTrack(*newTrack,extrapTrackParamAtCluster2);
778 0 : fNRecTracks++;
779 :
780 : // Printout for debuging
781 0 : if ((AliLog::GetDebugLevel("MUON","AliMUONTrackReconstructor") >= 1) || (AliLog::GetGlobalDebugLevel() >= 1)) {
782 0 : cout << "FollowTrackInStation: added one cluster in chamber(1..): " << ch2+1 << endl;
783 0 : if (AliLog::GetGlobalDebugLevel() >= 3) newTrack->RecursiveDump();
784 : }
785 :
786 0 : } else if (!foundTwoClusters && chi2WithOneCluster < bestChi2WithOneCluster) {
787 : // keep track of the best single cluster except if a couple of clusters has already been found
788 : bestChi2WithOneCluster = chi2WithOneCluster;
789 0 : bestTrackParamAtCluster1 = extrapTrackParamAtCluster2;
790 : }
791 :
792 : }
793 :
794 0 : }
795 :
796 : }
797 :
798 : // look for candidates in chamber 1 not already attached to a track
799 : // if we want to keep all possible tracks or if no good couple of clusters has been found
800 0 : if (GetRecoParam()->TrackAllTracks() || !foundTwoClusters) {
801 :
802 : // add MCS effect for next step
803 0 : AliMUONTrackExtrap::AddMCSEffect(&extrapTrackParamAtCh,AliMUONConstants::ChamberThicknessInX0(ch2),-1.);
804 :
805 : //Extrapolate trackCandidate to chamber "ch1"
806 0 : Bool_t normalExtrap = AliMUONTrackExtrap::ExtrapToZCov(&extrapTrackParamAtCh, AliMUONConstants::DefaultChamberZ(ch1));
807 :
808 : // Printout for debuging
809 0 : if ((AliLog::GetDebugLevel("MUON","AliMUONTrackReconstructor") >= 2) || (AliLog::GetGlobalDebugLevel() >= 2)) {
810 0 : cout<<endl<<"Track parameters and covariances at first cluster extrapolated to z = "<<AliMUONConstants::DefaultChamberZ(ch1)<<":"<<endl;
811 0 : extrapTrackParamAtCh.GetParameters().Print();
812 0 : extrapTrackParamAtCh.GetCovariances().Print();
813 : }
814 :
815 : // Printout for debuging
816 0 : if ((AliLog::GetDebugLevel("MUON","AliMUONTrackReconstructor") >= 1) || (AliLog::GetGlobalDebugLevel() >= 1)) {
817 0 : cout << "FollowTrackInStation: look for single clusters in chamber(1..): " << ch1+1 << endl;
818 : }
819 :
820 : // reset cluster iterator of chamber 1
821 0 : nextInCh1.Reset();
822 : iCluster1 = -1;
823 :
824 : // look for second candidates in chamber 1
825 0 : if (normalExtrap) while ( ( clusterCh1 = static_cast<AliMUONVCluster*>(nextInCh1()) ) ) {
826 0 : iCluster1++;
827 :
828 0 : if (clusterCh1Used[iCluster1]) continue; // Skip cluster already used
829 :
830 : // try to add the current cluster fast
831 0 : if (!TryOneClusterFast(extrapTrackParamAtCh, clusterCh1)) continue;
832 :
833 : // try to add the current cluster accuratly
834 0 : chi2WithOneCluster = TryOneCluster(extrapTrackParamAtCh, clusterCh1, extrapTrackParamAtCluster1);
835 :
836 : // if good chi2 then consider to add clusterCh1
837 : // We do not try to attach a cluster in the other chamber too since it has already been done above
838 0 : if (chi2WithOneCluster < maxChi2WithOneCluster) {
839 : foundOneCluster = kTRUE;
840 :
841 : // Printout for debuging
842 0 : if ((AliLog::GetDebugLevel("MUON","AliMUONTrackReconstructor") >= 1) || (AliLog::GetGlobalDebugLevel() >= 1)) {
843 0 : cout << "FollowTrackInStation: found one cluster in chamber(1..): " << ch1+1
844 0 : << " (Chi2 = " << chi2WithOneCluster << ")" << endl;
845 0 : clusterCh1->Print();
846 : }
847 :
848 0 : if (GetRecoParam()->TrackAllTracks()) {
849 : // copy trackCandidate into a new track put at the end of fRecTracksPtr and add the new cluster
850 0 : newTrack = new ((*fRecTracksPtr)[fRecTracksPtr->GetLast()+1]) AliMUONTrack(trackCandidate);
851 0 : UpdateTrack(*newTrack,extrapTrackParamAtCluster1);
852 0 : fNRecTracks++;
853 :
854 : // Printout for debuging
855 0 : if ((AliLog::GetDebugLevel("MUON","AliMUONTrackReconstructor") >= 1) || (AliLog::GetGlobalDebugLevel() >= 1)) {
856 0 : cout << "FollowTrackInStation: added one cluster in chamber(1..): " << ch1+1 << endl;
857 0 : if (AliLog::GetGlobalDebugLevel() >= 3) newTrack->RecursiveDump();
858 : }
859 :
860 0 : } else if (chi2WithOneCluster < bestChi2WithOneCluster) {
861 : // keep track of the best single cluster except if a couple of clusters has already been found
862 : bestChi2WithOneCluster = chi2WithOneCluster;
863 0 : bestTrackParamAtCluster1 = extrapTrackParamAtCluster1;
864 : }
865 :
866 : }
867 :
868 : }
869 :
870 0 : }
871 :
872 : // fill out the best track if required else clean up the fRecTracksPtr array
873 0 : if (!GetRecoParam()->TrackAllTracks()) {
874 0 : if (foundTwoClusters) {
875 0 : UpdateTrack(trackCandidate,bestTrackParamAtCluster1,bestTrackParamAtCluster2);
876 :
877 : // Printout for debuging
878 0 : if ((AliLog::GetDebugLevel("MUON","AliMUONTrackReconstructor") >= 1) || (AliLog::GetGlobalDebugLevel() >= 1)) {
879 0 : cout << "FollowTrackInStation: added the two best clusters in station(1..): " << nextStation+1 << endl;
880 0 : if (AliLog::GetGlobalDebugLevel() >= 3) trackCandidate.RecursiveDump();
881 : }
882 :
883 0 : } else if (foundOneCluster) {
884 0 : UpdateTrack(trackCandidate,bestTrackParamAtCluster1);
885 :
886 : // Printout for debuging
887 0 : if ((AliLog::GetDebugLevel("MUON","AliMUONTrackReconstructor") >= 1) || (AliLog::GetGlobalDebugLevel() >= 1)) {
888 0 : cout << "FollowTrackInStation: added the best cluster in chamber(1..): " << bestTrackParamAtCluster1.GetClusterPtr()->GetChamberId()+1 << endl;
889 0 : if (AliLog::GetGlobalDebugLevel() >= 3) trackCandidate.RecursiveDump();
890 : }
891 :
892 : } else {
893 0 : delete [] clusterCh1Used;
894 0 : return kFALSE;
895 : }
896 :
897 0 : } else if (foundOneCluster || foundTwoClusters) {
898 :
899 : // remove obsolete track
900 0 : fRecTracksPtr->Remove(&trackCandidate);
901 0 : fNRecTracks--;
902 :
903 : } else {
904 0 : delete [] clusterCh1Used;
905 0 : return kFALSE;
906 : }
907 :
908 0 : delete [] clusterCh1Used;
909 0 : return kTRUE;
910 :
911 0 : }
912 :
913 : //__________________________________________________________________________
914 : Double_t AliMUONTrackReconstructor::TryTwoClusters(const AliMUONTrackParam &trackParamAtCluster1, AliMUONVCluster* cluster2,
915 : AliMUONTrackParam &trackParamAtCluster2)
916 : {
917 : /// Test the compatibility between the track and the 2 clusters together (using trackParam's covariance matrix):
918 : /// return the corresponding Chi2 accounting for covariances between the 2 clusters
919 : /// return trackParamAtCluster1 & 2
920 :
921 : // extrapolate track parameters at the z position of the second cluster (no need to extrapolate the covariances)
922 : // and set pointer to cluster into trackParamAtCluster
923 0 : trackParamAtCluster2.SetParameters(trackParamAtCluster1.GetParameters());
924 0 : trackParamAtCluster2.SetZ(trackParamAtCluster1.GetZ());
925 0 : trackParamAtCluster2.SetClusterPtr(cluster2);
926 0 : if (!AliMUONTrackExtrap::ExtrapToZ(&trackParamAtCluster2, cluster2->GetZ())) return 2.*AliMUONTrack::MaxChi2();
927 :
928 : // Set differences between track and the 2 clusters in the bending and non bending directions
929 0 : AliMUONVCluster* cluster1 = trackParamAtCluster1.GetClusterPtr();
930 0 : TMatrixD dPos(4,1);
931 0 : dPos(0,0) = cluster1->GetX() - trackParamAtCluster1.GetNonBendingCoor();
932 0 : dPos(1,0) = cluster1->GetY() - trackParamAtCluster1.GetBendingCoor();
933 0 : dPos(2,0) = cluster2->GetX() - trackParamAtCluster2.GetNonBendingCoor();
934 0 : dPos(3,0) = cluster2->GetY() - trackParamAtCluster2.GetBendingCoor();
935 :
936 : // Calculate the error matrix from the track parameter covariances at first cluster
937 0 : TMatrixD error(4,4);
938 0 : error.Zero();
939 0 : if (trackParamAtCluster1.CovariancesExist()) {
940 : // Save track parameters at first cluster
941 0 : TMatrixD paramAtCluster1Save(trackParamAtCluster1.GetParameters());
942 :
943 : // Save track coordinates at second cluster
944 0 : Double_t nonBendingCoor2 = trackParamAtCluster2.GetNonBendingCoor();
945 0 : Double_t bendingCoor2 = trackParamAtCluster2.GetBendingCoor();
946 :
947 : // copy track parameters at first cluster for jacobian calculation
948 0 : AliMUONTrackParam trackParam(trackParamAtCluster1);
949 :
950 : // Get the pointer to the parameter covariance matrix at first cluster
951 0 : const TMatrixD& kParamCov = trackParam.GetCovariances();
952 :
953 : // Calculate the jacobian related to the transformation between track parameters
954 : // at first cluster and track coordinates at the 2 cluster z-positions
955 0 : TMatrixD jacob(4,5);
956 0 : jacob.Zero();
957 : // first derivative at the first cluster:
958 0 : jacob(0,0) = 1.; // dx1/dx
959 0 : jacob(1,2) = 1.; // dy1/dy
960 : // first derivative at the second cluster:
961 0 : TMatrixD dParam(5,1);
962 0 : Double_t direction[5] = {-1.,-1.,1.,1.,-1.};
963 0 : for (Int_t i=0; i<5; i++) {
964 : // Skip jacobian calculation for parameters with no associated error
965 0 : if (kParamCov(i,i) == 0.) continue;
966 : // Small variation of parameter i only
967 0 : for (Int_t j=0; j<5; j++) {
968 0 : if (j==i) {
969 0 : dParam(j,0) = TMath::Sqrt(kParamCov(i,i));
970 0 : dParam(j,0) *= TMath::Sign(1.,direction[j]*paramAtCluster1Save(j,0)); // variation always in the same direction
971 0 : } else dParam(j,0) = 0.;
972 : }
973 :
974 : // Set new track parameters at first cluster
975 0 : trackParam.SetParameters(paramAtCluster1Save);
976 0 : trackParam.AddParameters(dParam);
977 0 : trackParam.SetZ(cluster1->GetZ());
978 :
979 : // Extrapolate new track parameters to the z position of the second cluster
980 0 : if (!AliMUONTrackExtrap::ExtrapToZ(&trackParam,cluster2->GetZ())) return 2.*AliMUONTrack::MaxChi2();
981 :
982 : // Calculate the jacobian
983 0 : jacob(2,i) = (trackParam.GetNonBendingCoor() - nonBendingCoor2) / dParam(i,0); // dx2/dParami
984 0 : jacob(3,i) = (trackParam.GetBendingCoor() - bendingCoor2 ) / dParam(i,0); // dy2/dParami
985 0 : }
986 :
987 : // Calculate the error matrix
988 0 : TMatrixD tmp(jacob,TMatrixD::kMult,kParamCov);
989 0 : error = TMatrixD(tmp,TMatrixD::kMultTranspose,jacob);
990 0 : }
991 :
992 : // Add cluster resolution to the error matrix
993 0 : error(0,0) += cluster1->GetErrX2();
994 0 : error(1,1) += cluster1->GetErrY2();
995 0 : error(2,2) += cluster2->GetErrX2();
996 0 : error(3,3) += cluster2->GetErrY2();
997 :
998 : // invert the error matrix for Chi2 calculation
999 0 : if (error.Determinant() != 0) {
1000 0 : error.Invert();
1001 : } else {
1002 0 : AliWarning(" Determinant error=0");
1003 0 : return 2.*AliMUONTrack::MaxChi2();
1004 : }
1005 :
1006 : // Compute the Chi2 value
1007 0 : TMatrixD tmp2(dPos,TMatrixD::kTransposeMult,error);
1008 0 : TMatrixD result(tmp2,TMatrixD::kMult,dPos);
1009 :
1010 0 : return result(0,0);
1011 :
1012 0 : }
1013 :
1014 : //__________________________________________________________________________
1015 : void AliMUONTrackReconstructor::UpdateTrack(AliMUONTrack &track, AliMUONTrackParam &trackParamAtCluster)
1016 : {
1017 : /// Add 1 cluster to the track candidate
1018 : /// Update chi2 of the track
1019 :
1020 : // Compute local chi2
1021 0 : AliMUONVCluster* cluster = trackParamAtCluster.GetClusterPtr();
1022 0 : Double_t deltaX = trackParamAtCluster.GetNonBendingCoor() - cluster->GetX();
1023 0 : Double_t deltaY = trackParamAtCluster.GetBendingCoor() - cluster->GetY();
1024 0 : Double_t localChi2 = deltaX*deltaX / cluster->GetErrX2() +
1025 0 : deltaY*deltaY / cluster->GetErrY2();
1026 :
1027 : // Flag cluster as being not removable
1028 0 : if (GetRecoParam()->RequestStation(cluster->GetChamberId()/2))
1029 0 : trackParamAtCluster.SetRemovable(kFALSE);
1030 0 : else trackParamAtCluster.SetRemovable(kTRUE);
1031 0 : trackParamAtCluster.SetLocalChi2(0.); // --> Local chi2 not used
1032 :
1033 : // Update the chi2 of the new track
1034 0 : track.SetGlobalChi2(track.GetGlobalChi2() + localChi2);
1035 :
1036 : // Update TrackParamAtCluster
1037 0 : track.AddTrackParamAtCluster(trackParamAtCluster,*cluster);
1038 :
1039 0 : }
1040 :
1041 : //__________________________________________________________________________
1042 : void AliMUONTrackReconstructor::UpdateTrack(AliMUONTrack &track, AliMUONTrackParam &trackParamAtCluster1, AliMUONTrackParam &trackParamAtCluster2)
1043 : {
1044 : /// Add 2 clusters to the track candidate
1045 : /// Update track and local chi2
1046 :
1047 : // Update local chi2 at first cluster
1048 0 : AliMUONVCluster* cluster1 = trackParamAtCluster1.GetClusterPtr();
1049 0 : Double_t deltaX = trackParamAtCluster1.GetNonBendingCoor() - cluster1->GetX();
1050 0 : Double_t deltaY = trackParamAtCluster1.GetBendingCoor() - cluster1->GetY();
1051 0 : Double_t localChi2AtCluster1 = deltaX*deltaX / cluster1->GetErrX2() +
1052 0 : deltaY*deltaY / cluster1->GetErrY2();
1053 0 : trackParamAtCluster1.SetLocalChi2(localChi2AtCluster1);
1054 :
1055 : // Flag first cluster as being removable
1056 0 : trackParamAtCluster1.SetRemovable(kTRUE);
1057 :
1058 : // Update local chi2 at second cluster
1059 0 : AliMUONVCluster* cluster2 = trackParamAtCluster2.GetClusterPtr();
1060 0 : deltaX = trackParamAtCluster2.GetNonBendingCoor() - cluster2->GetX();
1061 0 : deltaY = trackParamAtCluster2.GetBendingCoor() - cluster2->GetY();
1062 0 : Double_t localChi2AtCluster2 = deltaX*deltaX / cluster2->GetErrX2() +
1063 0 : deltaY*deltaY / cluster2->GetErrY2();
1064 0 : trackParamAtCluster2.SetLocalChi2(localChi2AtCluster2);
1065 :
1066 : // Flag first cluster as being removable
1067 0 : trackParamAtCluster2.SetRemovable(kTRUE);
1068 :
1069 : // Update the chi2 of the new track
1070 0 : track.SetGlobalChi2(track.GetGlobalChi2() + localChi2AtCluster1 + localChi2AtCluster2);
1071 :
1072 : // Update TrackParamAtCluster
1073 0 : track.AddTrackParamAtCluster(trackParamAtCluster1,*cluster1);
1074 0 : track.AddTrackParamAtCluster(trackParamAtCluster2,*cluster2);
1075 :
1076 0 : }
1077 :
1078 : //__________________________________________________________________________
1079 : Bool_t AliMUONTrackReconstructor::RecoverTrack(AliMUONTrack &trackCandidate, AliMUONVClusterStore& clusterStore, Int_t nextStation)
1080 : {
1081 : /// Try to recover the track candidate in the next station
1082 : /// by removing the worst of the two clusters attached in the current station
1083 : /// Return kTRUE if recovering succeeds
1084 0 : AliDebug(1,"Enter RecoverTrack");
1085 :
1086 : // Do not try to recover track until we have attached cluster(s) on station(1..) 3
1087 0 : if (nextStation > 1) return kFALSE;
1088 :
1089 : Int_t worstClusterNumber = -1;
1090 : Double_t localChi2, worstLocalChi2 = -1.;
1091 :
1092 : // Look for the cluster to remove
1093 0 : for (Int_t clusterNumber = 0; clusterNumber < 2; clusterNumber++) {
1094 0 : AliMUONTrackParam *trackParamAtCluster = (AliMUONTrackParam*)trackCandidate.GetTrackParamAtCluster()->UncheckedAt(clusterNumber);
1095 :
1096 : // check if current cluster is in the previous station
1097 0 : if (trackParamAtCluster->GetClusterPtr()->GetChamberId()/2 != nextStation+1) break;
1098 :
1099 : // check if current cluster is removable
1100 0 : if (!trackParamAtCluster->IsRemovable()) return kFALSE;
1101 :
1102 : // reset the current cluster as beig not removable if it is on a required station
1103 0 : if (GetRecoParam()->RequestStation(nextStation+1)) trackParamAtCluster->SetRemovable(kFALSE);
1104 :
1105 : // Pick up cluster with the worst chi2
1106 0 : localChi2 = trackParamAtCluster->GetLocalChi2();
1107 0 : if (localChi2 > worstLocalChi2) {
1108 : worstLocalChi2 = localChi2;
1109 : worstClusterNumber = clusterNumber;
1110 0 : }
1111 :
1112 0 : }
1113 :
1114 : // check if worst cluster found
1115 0 : if (worstClusterNumber < 0) return kFALSE;
1116 :
1117 : // Remove the worst cluster
1118 0 : trackCandidate.RemoveTrackParamAtCluster((AliMUONTrackParam*)trackCandidate.GetTrackParamAtCluster()->UncheckedAt(worstClusterNumber));
1119 :
1120 : // Re-fit the track:
1121 : // Do not take into account the multiple scattering to speed up the fit
1122 : // Calculate the track parameter covariance matrix
1123 0 : Fit(trackCandidate, kFALSE, kFALSE, kTRUE);
1124 :
1125 : // skip track if the normalized chi2 is too high
1126 0 : if (trackCandidate.GetNormalizedChi2() > GetRecoParam()->GetSigmaCutForTracking() * GetRecoParam()->GetSigmaCutForTracking()) return kFALSE;
1127 :
1128 : // skip track out of limits
1129 0 : if (!IsAcceptable(*((AliMUONTrackParam*)trackCandidate.GetTrackParamAtCluster()->First()))) return kFALSE;
1130 :
1131 : // Look for new cluster(s) in next station
1132 0 : return FollowTrackInStation(trackCandidate,clusterStore,nextStation);
1133 :
1134 0 : }
1135 :
1136 : //__________________________________________________________________________
1137 : void AliMUONTrackReconstructor::SetVertexErrXY2ForFit(AliMUONTrack &trackCandidate)
1138 : {
1139 : /// Compute the vertex resolution square from natural vertex dispersion and
1140 : /// multiple scattering effets according to trackCandidate path in absorber
1141 : /// It is necessary to account for multiple scattering effects here instead of during the fit of
1142 : /// the "trackCandidate" to do not influence the result by changing track resolution at vertex
1143 0 : AliDebug(1,"Enter SetVertexForFit");
1144 :
1145 0 : Double_t nonBendingReso2 = GetRecoParam()->GetNonBendingVertexDispersion() *
1146 0 : GetRecoParam()->GetNonBendingVertexDispersion();
1147 0 : Double_t bendingReso2 = GetRecoParam()->GetBendingVertexDispersion() *
1148 0 : GetRecoParam()->GetBendingVertexDispersion();
1149 :
1150 : // add multiple scattering effets
1151 0 : AliMUONTrackParam paramAtVertex(*((AliMUONTrackParam*)(trackCandidate.GetTrackParamAtCluster()->First())));
1152 0 : paramAtVertex.DeleteCovariances(); // to be sure to account only for multiple scattering
1153 0 : if (!AliMUONTrackExtrap::ExtrapToZ(¶mAtVertex,AliMUONConstants::AbsZEnd())) {
1154 : nonBendingReso2 = 0.;
1155 : bendingReso2 = 0.;
1156 0 : } else {
1157 0 : AliMUONTrackExtrap::ExtrapToVertexUncorrected(¶mAtVertex,0.);
1158 0 : const TMatrixD& kParamCov = paramAtVertex.GetCovariances();
1159 0 : nonBendingReso2 += kParamCov(0,0);
1160 0 : bendingReso2 += kParamCov(2,2);
1161 : }
1162 :
1163 : // Set the vertex resolution square
1164 0 : trackCandidate.SetVertexErrXY2(nonBendingReso2,bendingReso2);
1165 0 : }
1166 :
1167 : //__________________________________________________________________________
1168 : void AliMUONTrackReconstructor::Fit(AliMUONTrack &track, Bool_t includeMCS, Bool_t fitWithVertex, Bool_t calcCov)
1169 : {
1170 : /// Fit the track
1171 : /// w/wo multiple Coulomb scattering according to "includeMCS".
1172 : /// w/wo constraining the vertex according to "fitWithVertex".
1173 : /// calculating or not the covariance matrix according to "calcCov".
1174 0 : AliDebug(1,"Enter Fit");
1175 :
1176 0 : Double_t benC, errorParam, invBenP, nonBenC, x, y;
1177 : AliMUONTrackParam *trackParam;
1178 0 : Double_t arg[1], fedm, errdef, globalChi2;
1179 0 : Int_t npari, nparx;
1180 0 : Int_t status, covStatus;
1181 :
1182 : // Instantiate gMinuit if not already done
1183 0 : if (!gMinuit) gMinuit = new TMinuit(6);
1184 : // Clear MINUIT parameters
1185 0 : gMinuit->mncler();
1186 : // Give the fitted track to MINUIT
1187 0 : gMinuit->SetObjectFit(&track);
1188 0 : if ((AliLog::GetDebugLevel("MUON","AliMUONTrackReconstructor") >= 2) || (AliLog::GetGlobalDebugLevel() >= 2)) {
1189 : // Define print level
1190 0 : arg[0] = 1;
1191 0 : gMinuit->mnexcm("SET PRI", arg, 1, status);
1192 : // Print covariance matrix
1193 0 : gMinuit->mnexcm("SHO COV", arg, 0, status);
1194 0 : } else {
1195 0 : arg[0] = -1;
1196 0 : gMinuit->mnexcm("SET PRI", arg, 1, status);
1197 : }
1198 : // No warnings
1199 0 : gMinuit->mnexcm("SET NOW", arg, 0, status);
1200 : // Define strategy
1201 : //arg[0] = 2;
1202 : //gMinuit->mnexcm("SET STR", arg, 1, status);
1203 :
1204 : // set flag w/wo multiple scattering according to "includeMCS"
1205 0 : track.FitWithMCS(includeMCS);
1206 0 : if (includeMCS) {
1207 : // compute cluster weights only once
1208 0 : if (!track.UpdateTrackParamAtCluster() || !track.ComputeClusterWeights()) {
1209 0 : AliWarning("cannot take into account the multiple scattering effects");
1210 0 : track.FitWithMCS(kFALSE);
1211 0 : }
1212 : }
1213 :
1214 0 : track.FitWithVertex(fitWithVertex);
1215 0 : if (fitWithVertex) SetVertexErrXY2ForFit(track);
1216 :
1217 : // Set fitting function
1218 0 : gMinuit->SetFCN(TrackChi2);
1219 :
1220 : // Set fitted parameters (!! The order is very important for the covariance matrix !!)
1221 : // Mandatory limits to avoid NaN values of parameters
1222 0 : trackParam = (AliMUONTrackParam*) (track.GetTrackParamAtCluster()->First());
1223 0 : Double_t maxIBM = 1. / GetRecoParam()->GetMinBendingMomentum();
1224 0 : gMinuit->mnparm(0, "X", trackParam->GetNonBendingCoor(), 0.03, -500.0, 500.0, status);
1225 0 : gMinuit->mnparm(1, "NonBenS", trackParam->GetNonBendingSlope(), 0.001, -1., 1., status);
1226 0 : gMinuit->mnparm(2, "Y", trackParam->GetBendingCoor(), 0.10, -500.0, 500.0, status);
1227 0 : gMinuit->mnparm(3, "BenS", trackParam->GetBendingSlope(), 0.001, -1.5, 1.5, status);
1228 0 : gMinuit->mnparm(4, "InvBenP", trackParam->GetInverseBendingMomentum(), 0.003, -maxIBM, maxIBM, status);
1229 :
1230 : // minimization
1231 0 : gMinuit->mnexcm("MIGRAD", arg, 0, status);
1232 :
1233 : // Calculate the covariance matrix more accurately if required
1234 0 : if (calcCov) gMinuit->mnexcm("HESSE", arg, 0, status);
1235 :
1236 : // get results into "invBenP", "benC", "nonBenC" ("x", "y")
1237 0 : gMinuit->GetParameter(0, x, errorParam);
1238 0 : trackParam->SetNonBendingCoor(x);
1239 0 : gMinuit->GetParameter(1, nonBenC, errorParam);
1240 0 : trackParam->SetNonBendingSlope(nonBenC);
1241 0 : gMinuit->GetParameter(2, y, errorParam);
1242 0 : trackParam->SetBendingCoor(y);
1243 0 : gMinuit->GetParameter(3, benC, errorParam);
1244 0 : trackParam->SetBendingSlope(benC);
1245 0 : gMinuit->GetParameter(4, invBenP, errorParam);
1246 0 : trackParam->SetInverseBendingMomentum(invBenP);
1247 :
1248 : // global result of the fit
1249 0 : gMinuit->mnstat(globalChi2, fedm, errdef, npari, nparx, covStatus);
1250 0 : track.SetGlobalChi2(globalChi2);
1251 :
1252 : // Get the covariance matrix if required
1253 0 : if (calcCov) {
1254 : // Covariance matrix according to HESSE status
1255 : // If problem then keep only the diagonal terms (variances)
1256 0 : Double_t matrix[5][5];
1257 0 : for (Int_t i=0; i<5; i++) for (Int_t j=0; j<5; j++) matrix[i][j] = 0.;
1258 0 : gMinuit->mnemat(&matrix[0][0],5);
1259 0 : if (covStatus == 3) trackParam->SetCovariances(matrix);
1260 0 : else trackParam->SetVariances(matrix);
1261 0 : } else trackParam->DeleteCovariances();
1262 :
1263 0 : }
1264 :
1265 : //__________________________________________________________________________
1266 : void TrackChi2(Int_t & /*nParam*/, Double_t * /*gradient*/, Double_t &chi2, Double_t *param, Int_t /*flag*/)
1267 : {
1268 : /// Return the "Chi2" to be minimized with Minuit for track fitting.
1269 : /// Assumes that the trackParamAtCluster are sorted according to increasing Z.
1270 : /// Track parameters at each cluster are updated accordingly.
1271 : /// Vertex is used according to the flag "trackBeingFitted->GetFitWithVertex()".
1272 : /// Multiple Coulomb scattering is taken into account according to the flag "trackBeingFitted->GetFitWithMCS()".
1273 :
1274 0 : AliMUONTrack *trackBeingFitted = (AliMUONTrack*) gMinuit->GetObjectFit();
1275 0 : AliMUONTrackParam* trackParamAtCluster = (AliMUONTrackParam*) trackBeingFitted->GetTrackParamAtCluster()->First();
1276 : Double_t dX, dY;
1277 0 : chi2 = 0.; // initialize chi2
1278 :
1279 : // update track parameters
1280 0 : trackParamAtCluster->SetNonBendingCoor(param[0]);
1281 0 : trackParamAtCluster->SetNonBendingSlope(param[1]);
1282 0 : trackParamAtCluster->SetBendingCoor(param[2]);
1283 0 : trackParamAtCluster->SetBendingSlope(param[3]);
1284 0 : trackParamAtCluster->SetInverseBendingMomentum(param[4]);
1285 0 : if (!trackBeingFitted->UpdateTrackParamAtCluster()) {
1286 0 : chi2 = 2.*AliMUONTrack::MaxChi2();
1287 0 : return;
1288 : }
1289 :
1290 : // Take the vertex into account in the fit if required
1291 0 : if (trackBeingFitted->FitWithVertex()) {
1292 0 : Double_t nonBendingReso2,bendingReso2;
1293 0 : trackBeingFitted->GetVertexErrXY2(nonBendingReso2,bendingReso2);
1294 0 : AliMUONTrackParam paramAtVertex(*trackParamAtCluster);
1295 0 : if (nonBendingReso2 != 0. && bendingReso2 != 0. && AliMUONTrackExtrap::ExtrapToZ(¶mAtVertex, 0.)) { // vextex position = (0,0,0)
1296 0 : dX = paramAtVertex.GetNonBendingCoor();
1297 0 : dY = paramAtVertex.GetBendingCoor();
1298 0 : chi2 += dX * dX / nonBendingReso2 + dY * dY / bendingReso2;
1299 : } else {
1300 0 : chi2 = 2.*AliMUONTrack::MaxChi2();
1301 0 : return;
1302 : }
1303 0 : }
1304 :
1305 : // compute chi2 w/wo multiple scattering
1306 0 : chi2 += trackBeingFitted->ComputeGlobalChi2(trackBeingFitted->FitWithMCS());
1307 :
1308 0 : }
1309 :
1310 : //__________________________________________________________________________
1311 : Bool_t AliMUONTrackReconstructor::ComplementTracks(const AliMUONVClusterStore& clusterStore)
1312 : {
1313 : /// Complete tracks by adding missing clusters (if there is an overlap between
1314 : /// two detection elements, the track may have two clusters in the same chamber).
1315 : /// Re-fit track parameters and covariances.
1316 : /// Return kTRUE if one or more tracks have been complemented.
1317 0 : AliDebug(1,"Enter ComplementTracks");
1318 :
1319 : Int_t chamberId, detElemId;
1320 : Double_t chi2OfCluster, bestChi2OfCluster;
1321 0 : Double_t sigmaCut2 = GetRecoParam()->GetSigmaCutForTracking() *
1322 0 : GetRecoParam()->GetSigmaCutForTracking();
1323 : Bool_t foundOneCluster, trackModified, hasChanged = kFALSE;
1324 : AliMUONVCluster* cluster;
1325 0 : AliMUONTrackParam *trackParam, *nextTrackParam, copyOfTrackParam, trackParamAtCluster, bestTrackParamAtCluster;
1326 :
1327 0 : AliMUONTrack *track = (AliMUONTrack*) fRecTracksPtr->First();
1328 0 : while (track) {
1329 : trackModified = kFALSE;
1330 :
1331 0 : trackParam = (AliMUONTrackParam*)track->GetTrackParamAtCluster()->First();
1332 0 : while (trackParam) {
1333 : foundOneCluster = kFALSE;
1334 0 : bestChi2OfCluster = 2. * sigmaCut2; // 2 because 2 quantities in chi2
1335 0 : chamberId = trackParam->GetClusterPtr()->GetChamberId();
1336 0 : detElemId = trackParam->GetClusterPtr()->GetDetElemId();
1337 :
1338 : // prepare nextTrackParam before adding new cluster because of the sorting
1339 0 : nextTrackParam = (AliMUONTrackParam*)track->GetTrackParamAtCluster()->After(trackParam);
1340 :
1341 : // recover track parameters from local fit and put them into a copy of trackParam
1342 0 : copyOfTrackParam.SetZ(trackParam->GetZ());
1343 0 : copyOfTrackParam.SetParameters(trackParam->GetSmoothParameters());
1344 0 : copyOfTrackParam.SetCovariances(trackParam->GetSmoothCovariances());
1345 :
1346 : // Create iterators to loop over clusters in current chamber
1347 0 : TIter nextInCh(clusterStore.CreateChamberIterator(chamberId,chamberId));
1348 :
1349 : // look for one second candidate in the same chamber
1350 0 : while ( ( cluster = static_cast<AliMUONVCluster*>(nextInCh()) ) ) {
1351 :
1352 : // look for a cluster in another detection element
1353 0 : if (cluster->GetDetElemId() == detElemId) continue;
1354 :
1355 : // try to add the current cluster fast
1356 0 : if (!TryOneClusterFast(copyOfTrackParam, cluster)) continue;
1357 :
1358 : // try to add the current cluster accurately
1359 0 : chi2OfCluster = TryOneCluster(copyOfTrackParam, cluster, trackParamAtCluster);
1360 :
1361 : // if better chi2 then prepare to add this cluster to the track
1362 0 : if (chi2OfCluster < bestChi2OfCluster) {
1363 : bestChi2OfCluster = chi2OfCluster;
1364 0 : bestTrackParamAtCluster = trackParamAtCluster;
1365 : foundOneCluster = kTRUE;
1366 0 : }
1367 :
1368 : }
1369 :
1370 : // add new cluster if any
1371 0 : if (foundOneCluster) {
1372 :
1373 : // Printout for debuging
1374 0 : if ((AliLog::GetDebugLevel("MUON","AliMUONTrackReconstructor") >= 1) || (AliLog::GetGlobalDebugLevel() >= 1)) {
1375 0 : cout << "ComplementTracks: found one cluster in chamber(1..): " << chamberId+1 << endl;
1376 0 : bestTrackParamAtCluster.GetClusterPtr()->Print();
1377 0 : cout<<endl<<"Track parameters and covariances at cluster:"<<endl;
1378 0 : bestTrackParamAtCluster.GetParameters().Print();
1379 0 : bestTrackParamAtCluster.GetCovariances().Print();
1380 : }
1381 :
1382 0 : trackParam->SetRemovable(kTRUE);
1383 0 : bestTrackParamAtCluster.SetRemovable(kTRUE);
1384 0 : track->AddTrackParamAtCluster(bestTrackParamAtCluster,*(bestTrackParamAtCluster.GetClusterPtr()));
1385 : trackModified = kTRUE;
1386 : hasChanged = kTRUE;
1387 0 : }
1388 :
1389 : trackParam = nextTrackParam;
1390 0 : }
1391 :
1392 : // re-fit track parameters if needed
1393 0 : if (trackModified) Fit(*track, kTRUE, kFALSE, kTRUE);
1394 :
1395 0 : track = (AliMUONTrack*) fRecTracksPtr->After(track);
1396 : }
1397 :
1398 0 : return hasChanged;
1399 :
1400 0 : }
1401 :
1402 : //__________________________________________________________________________
1403 : void AliMUONTrackReconstructor::ImproveTrack(AliMUONTrack &track)
1404 : {
1405 : /// Improve the given track by removing clusters with local chi2 highter than the defined cut
1406 : /// Recompute track parameters and covariances at the remaining clusters
1407 0 : AliDebug(1,"Enter ImproveTrack");
1408 :
1409 : Double_t localChi2, worstLocalChi2;
1410 : AliMUONTrackParam *trackParamAtCluster, *worstTrackParamAtCluster;
1411 0 : Double_t sigmaCut2 = GetRecoParam()->GetSigmaCutForImprovement() *
1412 0 : GetRecoParam()->GetSigmaCutForImprovement();
1413 :
1414 0 : while (!track.IsImproved()) {
1415 :
1416 : // identify removable clusters
1417 0 : track.TagRemovableClusters(GetRecoParam()->RequestedStationMask());
1418 :
1419 : // Update track parameters and covariances
1420 0 : if (!track.UpdateCovTrackParamAtCluster()) {
1421 0 : AliWarning("unable to update track parameters and covariances --> stop improvement");
1422 0 : break;
1423 : }
1424 :
1425 : // Compute local chi2 of each clusters
1426 0 : track.ComputeLocalChi2(kTRUE);
1427 :
1428 : // Look for the cluster to remove
1429 : worstTrackParamAtCluster = NULL;
1430 : worstLocalChi2 = 0.;
1431 0 : trackParamAtCluster = (AliMUONTrackParam*) track.GetTrackParamAtCluster()->First();
1432 0 : while (trackParamAtCluster) {
1433 :
1434 : // Pick up cluster with the worst chi2
1435 0 : localChi2 = trackParamAtCluster->GetLocalChi2();
1436 0 : if (localChi2 > worstLocalChi2) {
1437 : worstLocalChi2 = localChi2;
1438 : worstTrackParamAtCluster = trackParamAtCluster;
1439 0 : }
1440 :
1441 0 : trackParamAtCluster = (AliMUONTrackParam*) track.GetTrackParamAtCluster()->After(trackParamAtCluster);
1442 : }
1443 :
1444 : // Check if worst cluster found
1445 0 : if (!worstTrackParamAtCluster) {
1446 0 : AliWarning("Bad local chi2 values?");
1447 0 : break;
1448 : }
1449 :
1450 : // Check whether the worst chi2 is under requirement or not
1451 0 : if (worstLocalChi2 < 2. * sigmaCut2) { // 2 because 2 quantities in chi2
1452 0 : track.SetImproved(kTRUE);
1453 0 : break;
1454 : }
1455 :
1456 : // if the worst cluster is not removable then stop improvement
1457 0 : if (!worstTrackParamAtCluster->IsRemovable()) break;
1458 :
1459 : // Remove the worst cluster
1460 0 : track.RemoveTrackParamAtCluster(worstTrackParamAtCluster);
1461 :
1462 : // Re-fit the track:
1463 : // Take into account the multiple scattering
1464 : // Calculate the track parameter covariance matrix
1465 0 : Fit(track, kTRUE, kFALSE, kTRUE);
1466 :
1467 : // Printout for debuging
1468 0 : if ((AliLog::GetDebugLevel("MUON","AliMUONTrackReconstructor") >= 1) || (AliLog::GetGlobalDebugLevel() >= 1)) {
1469 0 : cout << "ImproveTracks: track " << fRecTracksPtr->IndexOf(&track)+1 << " improved " << endl;
1470 0 : }
1471 :
1472 : }
1473 :
1474 0 : }
1475 :
1476 : //__________________________________________________________________________
1477 : Bool_t AliMUONTrackReconstructor::FinalizeTrack(AliMUONTrack &track)
1478 : {
1479 : /// Recompute track parameters and covariances at each attached cluster
1480 : /// from those at the first one, if not already done
1481 0 : AliDebug(1,"Enter FinalizeTrack");
1482 0 : if (!track.IsImproved() && !track.UpdateCovTrackParamAtCluster()) {
1483 0 : AliWarning("finalization failed due to extrapolation problem");
1484 0 : return kFALSE;
1485 : }
1486 0 : return kTRUE;
1487 0 : }
1488 :
1489 : //__________________________________________________________________________
1490 : Bool_t AliMUONTrackReconstructor::RefitTrack(AliMUONTrack &track, Bool_t enableImprovement)
1491 : {
1492 : /// re-fit the given track
1493 :
1494 : // check validity of the track
1495 0 : if (track.GetNClusters() < 3) {
1496 0 : AliWarning("the track does not contain enough clusters --> unable to refit");
1497 0 : return kFALSE;
1498 : }
1499 :
1500 : // reset the seed (i.e. parameters at first cluster) before fitting
1501 0 : AliMUONTrackParam* firstTrackParam = (AliMUONTrackParam*) track.GetTrackParamAtCluster()->First();
1502 0 : if (firstTrackParam->GetInverseBendingMomentum() == 0.) {
1503 0 : AliWarning("track parameters at first chamber are not initialized --> unable to refit");
1504 0 : return kFALSE;
1505 : }
1506 :
1507 : // compute track parameters at each cluster from parameters at the first one
1508 : // necessary to compute multiple scattering effect during refitting
1509 0 : if (!track.UpdateTrackParamAtCluster()) {
1510 0 : AliWarning("bad track refitting due to extrapolation failure");
1511 0 : return kFALSE;
1512 : }
1513 :
1514 : // Re-fit the track:
1515 : // Take into account the multiple scattering
1516 : // Calculate the track parameter covariance matrix
1517 0 : Fit(track, kTRUE, kFALSE, kTRUE);
1518 :
1519 : // Improve the reconstructed tracks if required
1520 0 : track.SetImproved(kFALSE);
1521 0 : if (enableImprovement && GetRecoParam()->ImproveTracks()) ImproveTrack(track);
1522 :
1523 : // Fill AliMUONTrack data members
1524 0 : if (track.GetGlobalChi2() < AliMUONTrack::MaxChi2()) return FinalizeTrack(track);
1525 : else {
1526 0 : AliWarning("track not finalized due to extrapolation failure");
1527 0 : return kFALSE;
1528 : }
1529 :
1530 0 : }
1531 :
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