1 /**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
7 * Permission to use, copy, modify and distribute this software and its *
8 * documentation strictly for non-commercial purposes is hereby granted *
9 * without fee, provided that the above copyright notice appears in all *
10 * copies and that both the copyright notice and this permission notice *
11 * appear in the supporting documentation. The authors make no claims *
12 * about the suitability of this software for any purpose. It is *
13 * provided "as is" without express or implied warranty. *
14 **************************************************************************/
18 Revision 1.12 2001/04/25 14:50:42 gosset
19 Corrections to violations of coding conventions
21 Revision 1.11 2001/04/23 12:33:17 hristov
22 Arrays with variable size created by new and deleted at the end
24 Revision 1.10 2001/04/09 12:25:09 gosset
25 Inversion of covariance matrices with local copy of TMinuit::mnvert,
26 for symmetric positive definite matrices, instead of TMatrixD::Invert
28 Revision 1.9 2001/01/17 20:59:24 hristov
31 Revision 1.8 2001/01/08 11:01:02 gosset
32 Modifications used for addendum to Dimuon TDR (JP Cussonneau):
33 *. MaxBendingMomentum to make both a segment and a track (default 500)
34 *. MaxChi2 per degree of freedom to make a track (default 100)
35 *. MinBendingMomentum used also to make a track
36 and not only a segment (default 3)
37 *. wider roads for track search in stations 1 to 3
38 *. extrapolation to actual Z instead of Z(chamber) in FollowTracks
40 - limits on parameters X and Y (+/-500)
41 - covariance matrices in double precision
42 - normalization of covariance matrices before inversion
43 - suppression of Minuit printouts
44 *. correction against memory leak (delete extrapHit) in FollowTracks
45 *. RMax to 10 degrees with Z(chamber) instead of fixed values;
46 RMin and Rmax cuts suppressed in NewHitForRecFromGEANT,
47 because useless with realistic geometry
49 Revision 1.7 2000/09/19 15:50:46 gosset
50 TrackChi2MCS function: covariance matrix better calculated,
51 taking into account missing planes...
53 Revision 1.6 2000/07/20 12:45:27 gosset
54 New "EventReconstructor..." structure,
55 hopefully more adapted to tree/streamer.
56 "AliMUONEventReconstructor::RemoveDoubleTracks"
57 to keep only one track among similar ones.
59 Revision 1.5 2000/07/18 16:04:06 gosset
60 AliMUONEventReconstructor package:
61 * a few minor modifications and more comments
63 * right sign for Z of raw clusters
64 * right loop over chambers inside station
65 * symmetrized covariance matrix for measurements (TrackChi2MCS)
66 * right sign of charge in extrapolation (ExtrapToZ)
67 * right zEndAbsorber for Branson correction below 3 degrees
68 * use of TVirtualFitter instead of TMinuit for AliMUONTrack::Fit
69 * no parameter for AliMUONTrack::Fit() but more fit parameters in Track object
71 Revision 1.4 2000/06/30 10:15:48 gosset
72 Changes to EventReconstructor...:
73 precision fit with multiple Coulomb scattering;
74 extrapolation to vertex with Branson correction in absorber (JPC)
76 Revision 1.3 2000/06/25 13:23:28 hristov
77 stdlib.h needed for non-Linux compilation
79 Revision 1.2 2000/06/15 07:58:48 morsch
80 Code from MUON-dev joined
82 Revision 1.1.2.3 2000/06/12 10:11:34 morsch
83 Dummy copy constructor and assignment operator added
85 Revision 1.1.2.2 2000/06/09 12:58:05 gosset
86 Removed comment beginnings in Log sections of .cxx files
87 Suppressed most violations of coding rules
89 Revision 1.1.2.1 2000/06/07 14:44:53 gosset
90 Addition of files for track reconstruction in C++
93 ///////////////////////////////////////////////////
95 // Reconstructed track
101 ///////////////////////////////////////////////////
103 #include <iostream.h> // for cout
104 #include <stdlib.h> // for exit()
106 #include <TClonesArray.h>
108 #include <TMatrixD.h>
109 #include <TObjArray.h>
110 #include <TVirtualFitter.h>
112 #include "AliMUONEventReconstructor.h"
113 #include "AliMUONHitForRec.h"
114 #include "AliMUONSegment.h"
115 #include "AliMUONTrack.h"
116 #include "AliMUONTrackHit.h"
118 // Functions to be minimized with Minuit
119 void TrackChi2(Int_t &NParam, Double_t *Gradient, Double_t &Chi2, Double_t *Param, Int_t Flag);
120 void TrackChi2MCS(Int_t &NParam, Double_t *Gradient, Double_t &Chi2, Double_t *Param, Int_t Flag);
122 void mnvertLocal(Double_t* a, Int_t l, Int_t m, Int_t n, Int_t& ifail);
124 Double_t MultipleScatteringAngle2(AliMUONTrackHit *TrackHit);
126 ClassImp(AliMUONTrack) // Class implementation in ROOT context
128 TVirtualFitter* AliMUONTrack::fgFitter = NULL;
130 //__________________________________________________________________________
131 AliMUONTrack::AliMUONTrack(AliMUONSegment* BegSegment, AliMUONSegment* EndSegment, AliMUONEventReconstructor* EventReconstructor)
133 // Constructor from two Segment's
134 fEventReconstructor = EventReconstructor; // link back to EventReconstructor
135 // memory allocation for the TObjArray of pointers to reconstructed TrackHit's
136 fTrackHitsPtr = new TObjArray(10);
138 AddSegment(BegSegment); // add hits from BegSegment
139 AddSegment(EndSegment); // add hits from EndSegment
140 fTrackHitsPtr->Sort(); // sort TrackHits according to increasing Z
141 SetTrackParamAtVertex(); // set track parameters at vertex
142 // set fit conditions...
150 //__________________________________________________________________________
151 AliMUONTrack::AliMUONTrack(AliMUONSegment* Segment, AliMUONHitForRec* HitForRec, AliMUONEventReconstructor* EventReconstructor)
153 // Constructor from one Segment and one HitForRec
154 fEventReconstructor = EventReconstructor; // link back to EventReconstructor
155 // memory allocation for the TObjArray of pointers to reconstructed TrackHit's
156 fTrackHitsPtr = new TObjArray(10);
158 AddSegment(Segment); // add hits from Segment
159 AddHitForRec(HitForRec); // add HitForRec
160 fTrackHitsPtr->Sort(); // sort TrackHits according to increasing Z
161 SetTrackParamAtVertex(); // set track parameters at vertex
162 // set fit conditions...
170 //__________________________________________________________________________
171 AliMUONTrack::~AliMUONTrack()
175 delete fTrackHitsPtr; // delete the TObjArray of pointers to TrackHit's
176 fTrackHitsPtr = NULL;
180 //__________________________________________________________________________
181 AliMUONTrack::AliMUONTrack (const AliMUONTrack& MUONTrack)
183 // Dummy copy constructor
186 //__________________________________________________________________________
187 AliMUONTrack & AliMUONTrack::operator=(const AliMUONTrack& MUONTrack)
189 // Dummy assignment operator
193 //__________________________________________________________________________
194 void AliMUONTrack::Remove()
196 // Remove current track from array of tracks,
197 // and corresponding track hits from array of track hits.
198 // Compress the TClonesArray it belongs to.
199 AliMUONTrackHit *nextTrackHit;
200 AliMUONEventReconstructor *eventRec = this->fEventReconstructor;
201 TClonesArray *trackHitsPtr = eventRec->GetRecTrackHitsPtr();
202 // Loop over all track hits of track
203 AliMUONTrackHit *trackHit = (AliMUONTrackHit*) fTrackHitsPtr->First();
205 nextTrackHit = (AliMUONTrackHit*) fTrackHitsPtr->After(trackHit);
206 // Remove TrackHit from event TClonesArray.
207 // Destructor is called,
208 // hence links between HitForRec's and TrackHit's are updated
209 trackHitsPtr->Remove(trackHit);
210 trackHit = nextTrackHit;
212 // Remove the track from event TClonesArray
213 // Destructor is called,
214 // hence space for TObjArray of pointers to TrackHit's is freed
215 eventRec->GetRecTracksPtr()->Remove(this);
216 // Number of tracks decreased by 1
217 eventRec->SetNRecTracks(eventRec->GetNRecTracks() - 1);
218 // Compress event TClonesArray of Track's:
219 // this is essential to retrieve the TClonesArray afterwards
220 eventRec->GetRecTracksPtr()->Compress();
221 // Compress event TClonesArray of TrackHit's:
222 // this is probably also essential to retrieve the TClonesArray afterwards
223 trackHitsPtr->Compress();
226 //__________________________________________________________________________
227 void AliMUONTrack::SetFitMCS(Int_t FitMCS)
229 // Set multiple Coulomb scattering option for track fit "fFitMCS"
230 // from "FitMCS" argument: 0 without, 1 with
231 if ((FitMCS == 0) || (FitMCS == 1)) fFitMCS = FitMCS;
232 // better implementation with enum(with, without) ????
234 cout << "ERROR in AliMUONTrack::SetFitMCS(FitMCS)" << endl;
235 cout << "FitMCS = " << FitMCS << " is neither 0 nor 1" << endl;
241 //__________________________________________________________________________
242 void AliMUONTrack::SetFitNParam(Int_t FitNParam)
244 // Set number of parameters for track fit "fFitNParam" from "FitNParam":
245 // 3 for momentum, 5 for momentum and position
246 if ((FitNParam == 3) || (FitNParam == 5)) fFitNParam = FitNParam;
248 cout << "ERROR in AliMUONTrack::SetFitNParam(FitNParam)" << endl;
249 cout << "FitNParam = " << FitNParam << " is neither 3 nor 5" << endl;
255 //__________________________________________________________________________
256 void AliMUONTrack::SetFitStart(Int_t FitStart)
258 // Set multiple Coulomb scattering option for track fit "fFitStart"
259 // from "FitStart" argument: 0 without, 1 with
260 if ((FitStart == 0) || (FitStart == 1)) fFitStart = FitStart;
261 // better implementation with enum(vertex, firstHit) ????
263 cout << "ERROR in AliMUONTrack::SetFitStart(FitStart)" << endl;
264 cout << "FitStart = " << FitStart << " is neither 0 nor 1" << endl;
270 //__________________________________________________________________________
271 AliMUONTrackParam* AliMUONTrack::GetTrackParamAtFirstHit(void) const {
272 // Get pointer to TrackParamAtFirstHit
273 return ((AliMUONTrackHit*) (fTrackHitsPtr->First()))->GetTrackParam();}
275 //__________________________________________________________________________
276 void AliMUONTrack::RecursiveDump(void) const
278 // Recursive dump of AliMUONTrack, i.e. with dump of TrackHit's and HitForRec's
279 AliMUONTrackHit *trackHit;
280 AliMUONHitForRec *hitForRec;
281 cout << "Recursive dump of Track: " << this << endl;
284 for (Int_t trackHitIndex = 0; trackHitIndex < fNTrackHits; trackHitIndex++) {
285 trackHit = (AliMUONTrackHit*) ((*fTrackHitsPtr)[trackHitIndex]);
287 cout << "TrackHit: " << trackHit << " (index: " << trackHitIndex << ")" << endl;
289 hitForRec = trackHit->GetHitForRecPtr();
291 cout << "HitForRec: " << hitForRec << endl;
297 //__________________________________________________________________________
298 Int_t AliMUONTrack::HitsInCommon(AliMUONTrack* Track)
300 // Returns the number of hits in common
301 // between the current track ("this")
302 // and the track pointed to by "Track".
303 Int_t hitsInCommon = 0;
304 AliMUONTrackHit *trackHit1, *trackHit2;
305 // Loop over hits of first track
306 trackHit1 = (AliMUONTrackHit*) this->GetTrackHitsPtr()->First();
308 // Loop over hits of second track
309 trackHit2 = (AliMUONTrackHit*) Track->GetTrackHitsPtr()->First();
311 // Increment "hitsInCommon" if both TrackHits point to the same HitForRec
312 if ( (trackHit1->GetHitForRecPtr()) ==
313 (trackHit2->GetHitForRecPtr()) ) hitsInCommon++;
314 trackHit2 = (AliMUONTrackHit*) Track->GetTrackHitsPtr()->After(trackHit2);
316 trackHit1 = (AliMUONTrackHit*) this->GetTrackHitsPtr()->After(trackHit1);
321 //__________________________________________________________________________
322 void AliMUONTrack::Fit()
324 // Fit the current track ("this"),
325 // with or without multiple Coulomb scattering according to "fFitMCS",
326 // with the number of parameters given by "fFitNParam"
327 // (3 if one keeps X and Y fixed in "TrackParam", 5 if one lets them vary),
328 // starting, according to "fFitStart",
329 // with track parameters at vertex or at the first TrackHit.
330 // "fFitMCS", "fFitNParam" and "fFitStart" have to be set before
331 // by calling the corresponding Set methods.
332 Double_t arg[1], benC, errorParam, invBenP, lower, nonBenC, upper, x, y;
334 AliMUONTrackParam *trackParam;
335 // Check if Minuit is initialized...
336 fgFitter = TVirtualFitter::Fitter(this); // add 3 or 5 for the maximum number of parameters ???
337 fgFitter->Clear(); // necessary ???? probably yes
338 // how to reset the printout number at every fit ????
339 // is there any risk to leave it like that ????
340 // how to go faster ???? choice of Minuit parameters like EDM ????
341 // choice of function to be minimized according to fFitMCS
342 if (fFitMCS == 0) fgFitter->SetFCN(TrackChi2);
343 else fgFitter->SetFCN(TrackChi2MCS);
345 fgFitter->ExecuteCommand("SET PRINT", arg, 1); // More printing !!!!
346 // Parameters according to "fFitStart"
347 // (should be a function to be used at every place where needed ????)
348 if (fFitStart == 0) trackParam = &fTrackParamAtVertex;
349 else trackParam = this->GetTrackParamAtFirstHit();
350 // set first 3 Minuit parameters
351 // could be tried with no limits for the search (min=max=0) ????
352 fgFitter->SetParameter(0, "InvBenP",
353 trackParam->GetInverseBendingMomentum(),
355 fgFitter->SetParameter(1, "BenS",
356 trackParam->GetBendingSlope(),
358 fgFitter->SetParameter(2, "NonBenS",
359 trackParam->GetNonBendingSlope(),
361 if (fFitNParam == 5) {
362 // set last 2 Minuit parameters
363 // mandatory limits in Bending to avoid NaN values of parameters
364 fgFitter->SetParameter(3, "X",
365 trackParam->GetNonBendingCoor(),
366 0.03, -500.0, 500.0);
367 // mandatory limits in non Bending to avoid NaN values of parameters
368 fgFitter->SetParameter(4, "Y",
369 trackParam->GetBendingCoor(),
370 0.10, -500.0, 500.0);
372 // search without gradient calculation in the function
373 fgFitter->ExecuteCommand("SET NOGRADIENT", arg, 0);
375 fgFitter->ExecuteCommand("MINIMIZE", arg, 0);
377 fgFitter->ExecuteCommand("EXIT", arg, 0); // necessary ????
378 // get results into "invBenP", "benC", "nonBenC" ("x", "y")
379 fgFitter->GetParameter(0, parName, invBenP, errorParam, lower, upper);
380 fgFitter->GetParameter(1, parName, benC, errorParam, lower, upper);
381 fgFitter->GetParameter(2, parName, nonBenC, errorParam, lower, upper);
382 if (fFitNParam == 5) {
383 fgFitter->GetParameter(3, parName, x, errorParam, lower, upper);
384 fgFitter->GetParameter(4, parName, y, errorParam, lower, upper);
386 // result of the fit into track parameters
387 trackParam->SetInverseBendingMomentum(invBenP);
388 trackParam->SetBendingSlope(benC);
389 trackParam->SetNonBendingSlope(nonBenC);
390 if (fFitNParam == 5) {
391 trackParam->SetNonBendingCoor(x);
392 trackParam->SetBendingCoor(y);
394 // global result of the fit
395 Double_t fedm, errdef;
397 fgFitter->GetStats(fFitFMin, fedm, errdef, npari, nparx);
400 //__________________________________________________________________________
401 void AliMUONTrack::AddSegment(AliMUONSegment* Segment)
403 // Add Segment to the track
404 AddHitForRec(Segment->GetHitForRec1()); // 1st hit
405 AddHitForRec(Segment->GetHitForRec2()); // 2nd hit
408 //__________________________________________________________________________
409 void AliMUONTrack::AddHitForRec(AliMUONHitForRec* HitForRec)
411 // Add HitForRec to the track:
412 // actual TrackHit into TClonesArray of TrackHit's for the event;
413 // pointer to actual TrackHit in TObjArray of pointers to TrackHit's for the track
414 TClonesArray *recTrackHitsPtr = this->fEventReconstructor->GetRecTrackHitsPtr();
415 Int_t eventTrackHits = this->fEventReconstructor->GetNRecTrackHits();
417 AliMUONTrackHit* trackHit =
418 new ((*recTrackHitsPtr)[eventTrackHits]) AliMUONTrackHit(HitForRec);
419 this->fEventReconstructor->SetNRecTrackHits(eventTrackHits + 1);
421 fTrackHitsPtr->Add(trackHit);
425 //__________________________________________________________________________
426 void AliMUONTrack::SetTrackParamAtHit(Int_t indexHit, AliMUONTrackParam *TrackParam) const
428 // Set track parameters at TrackHit with index "indexHit"
429 // from the track parameters pointed to by "TrackParam".
430 AliMUONTrackHit* trackHit = (AliMUONTrackHit*) ((*fTrackHitsPtr)[indexHit]);
431 trackHit->SetTrackParam(TrackParam);
434 //__________________________________________________________________________
435 void AliMUONTrack::SetTrackParamAtVertex()
437 // Set track parameters at vertex.
438 // TrackHit's are assumed to be only in stations(1..) 4 and 5,
439 // and sorted according to increasing Z..
440 // Parameters are calculated from information in HitForRec's
441 // of first and last TrackHit's.
442 AliMUONTrackParam *trackParam =
443 &fTrackParamAtVertex; // pointer to track parameters
444 // Pointer to HitForRec of first TrackHit
445 AliMUONHitForRec *firstHit =
446 ((AliMUONTrackHit*) (fTrackHitsPtr->First()))->GetHitForRecPtr();
447 // Pointer to HitForRec of last TrackHit
448 AliMUONHitForRec *lastHit =
449 ((AliMUONTrackHit*) (fTrackHitsPtr->Last()))->GetHitForRecPtr();
450 // Z difference between first and last hits
451 Double_t deltaZ = firstHit->GetZ() - lastHit->GetZ();
452 // bending slope in stations(1..) 4 and 5
453 Double_t bendingSlope =
454 (firstHit->GetBendingCoor() - lastHit->GetBendingCoor()) / deltaZ;
455 trackParam->SetBendingSlope(bendingSlope);
457 Double_t impactParam =
458 firstHit->GetBendingCoor() - bendingSlope * firstHit->GetZ(); // same if from firstHit and lastHit ????
459 // signed bending momentum
460 Double_t signedBendingMomentum =
461 fEventReconstructor->GetBendingMomentumFromImpactParam(impactParam);
462 trackParam->SetInverseBendingMomentum(1.0 / signedBendingMomentum);
463 // bending slope at vertex
465 SetBendingSlope(bendingSlope +
466 impactParam / fEventReconstructor->GetSimpleBPosition());
468 Double_t nonBendingSlope =
469 (firstHit->GetNonBendingCoor() - lastHit->GetNonBendingCoor()) / deltaZ;
470 trackParam->SetNonBendingSlope(nonBendingSlope);
471 // vertex coordinates at (0,0,0)
472 trackParam->SetZ(0.0);
473 trackParam->SetBendingCoor(0.0);
474 trackParam->SetNonBendingCoor(0.0);
477 //__________________________________________________________________________
478 void TrackChi2(Int_t &NParam, Double_t *Gradient, Double_t &Chi2, Double_t *Param, Int_t Flag)
480 // Return the "Chi2" to be minimized with Minuit for track fitting,
481 // with "NParam" parameters
482 // and their current values in array pointed to by "Param".
483 // Assumes that the track hits are sorted according to increasing Z.
484 // Track parameters at each TrackHit are updated accordingly.
485 // Multiple Coulomb scattering is not taken into account
486 AliMUONTrack *trackBeingFitted;
487 AliMUONTrackHit* hit;
488 AliMUONTrackParam param1;
491 Chi2 = 0.0; // initialize Chi2
492 // copy of track parameters to be fitted
493 trackBeingFitted = (AliMUONTrack*) AliMUONTrack::Fitter()->GetObjectFit();
494 if (trackBeingFitted->GetFitStart() == 0)
495 param1 = *(trackBeingFitted->GetTrackParamAtVertex());
496 else param1 = *(trackBeingFitted->GetTrackParamAtFirstHit());
497 // Minuit parameters to be fitted into this copy
498 param1.SetInverseBendingMomentum(Param[0]);
499 param1.SetBendingSlope(Param[1]);
500 param1.SetNonBendingSlope(Param[2]);
502 param1.SetNonBendingCoor(Param[3]);
503 param1.SetBendingCoor(Param[4]);
505 // Follow track through all planes of track hits
506 for (hitNumber = 0; hitNumber < trackBeingFitted->GetNTrackHits(); hitNumber++) {
507 hit = (AliMUONTrackHit*) (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber];
508 zHit = hit->GetHitForRecPtr()->GetZ();
509 // do something special if 2 hits with same Z ????
510 // security against infinite loop ????
511 (¶m1)->ExtrapToZ(zHit); // extrapolation
512 hit->SetTrackParam(¶m1);
514 // done hit per hit, with hit resolution,
515 // and not with point and angle like in "reco_muon.F" !!!!
516 // Needs to add multiple scattering contribution ????
518 hit->GetHitForRecPtr()->GetNonBendingCoor() - (¶m1)->GetNonBendingCoor();
520 hit->GetHitForRecPtr()->GetBendingCoor() - (¶m1)->GetBendingCoor();
523 dX * dX / hit->GetHitForRecPtr()->GetNonBendingReso2() +
524 dY * dY / hit->GetHitForRecPtr()->GetBendingReso2();
528 //__________________________________________________________________________
529 void TrackChi2MCS(Int_t &NParam, Double_t *Gradient, Double_t &Chi2, Double_t *Param, Int_t Flag)
531 // Return the "Chi2" to be minimized with Minuit for track fitting,
532 // with "NParam" parameters
533 // and their current values in array pointed to by "Param".
534 // Assumes that the track hits are sorted according to increasing Z.
535 // Track parameters at each TrackHit are updated accordingly.
536 // Multiple Coulomb scattering is taken into account with covariance matrix.
537 AliMUONTrack *trackBeingFitted;
538 AliMUONTrackParam param1;
539 Chi2 = 0.0; // initialize Chi2
540 // copy of track parameters to be fitted
541 trackBeingFitted = (AliMUONTrack*) AliMUONTrack::Fitter()->GetObjectFit();
542 if (trackBeingFitted->GetFitStart() == 0)
543 param1 = *(trackBeingFitted->GetTrackParamAtVertex());
544 else param1 = *(trackBeingFitted->GetTrackParamAtFirstHit());
545 // Minuit parameters to be fitted into this copy
546 param1.SetInverseBendingMomentum(Param[0]);
547 param1.SetBendingSlope(Param[1]);
548 param1.SetNonBendingSlope(Param[2]);
550 param1.SetNonBendingCoor(Param[3]);
551 param1.SetBendingCoor(Param[4]);
554 AliMUONTrackHit *hit;
555 Int_t chCurrent, chPrev = 0, hitNumber, hitNumber1, hitNumber2, hitNumber3;
556 Double_t z, z1, z2, z3;
557 AliMUONTrackHit *hit1, *hit2, *hit3;
558 Double_t hbc1, hbc2, pbc1, pbc2;
559 Double_t hnbc1, hnbc2, pnbc1, pnbc2;
560 Int_t numberOfHit = trackBeingFitted->GetNTrackHits();
561 TMatrixD *covBending = new TMatrixD(numberOfHit, numberOfHit);
562 TMatrixD *covNonBending = new TMatrixD(numberOfHit, numberOfHit);
563 Double_t *msa2 = new Double_t[numberOfHit];
565 // Predicted coordinates and multiple scattering angles are first calculated
566 for (hitNumber = 0; hitNumber < numberOfHit; hitNumber++) {
567 hit = (AliMUONTrackHit*) (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber];
568 z = hit->GetHitForRecPtr()->GetZ();
569 // do something special if 2 hits with same Z ????
570 // security against infinite loop ????
571 (¶m1)->ExtrapToZ(z); // extrapolation
572 hit->SetTrackParam(¶m1);
573 // square of multiple scattering angle at current hit, with one chamber
574 msa2[hitNumber] = MultipleScatteringAngle2(hit);
575 // correction for eventual missing hits or multiple hits in a chamber,
576 // according to the number of chambers
577 // between the current hit and the previous one
578 chCurrent = hit->GetHitForRecPtr()->GetChamberNumber();
579 if (hitNumber > 0) msa2[hitNumber] = msa2[hitNumber] * (chCurrent - chPrev);
583 // Calculates the covariance matrix
584 for (hitNumber1 = 0; hitNumber1 < numberOfHit; hitNumber1++) {
585 hit1 = (AliMUONTrackHit*) (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber1];
586 z1 = hit1->GetHitForRecPtr()->GetZ();
587 for (hitNumber2 = hitNumber1; hitNumber2 < numberOfHit; hitNumber2++) {
588 hit2 = (AliMUONTrackHit*) (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber2];
589 z2 = hit2->GetHitForRecPtr()->GetZ();
590 // initialization to 0 (diagonal plus upper triangular part)
591 (*covBending)(hitNumber2, hitNumber1) = 0.0;
592 // contribution from multiple scattering in bending plane:
593 // loop over upstream hits
594 for (hitNumber3 = 0; hitNumber3 < hitNumber1; hitNumber3++) {
595 hit3 = (AliMUONTrackHit*)
596 (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber3];
597 z3 = hit3->GetHitForRecPtr()->GetZ();
598 (*covBending)(hitNumber2, hitNumber1) =
599 (*covBending)(hitNumber2, hitNumber1) +
600 ((z1 - z3) * (z2 - z3) * msa2[hitNumber3]);
602 // equal contribution from multiple scattering in non bending plane
603 (*covNonBending)(hitNumber2, hitNumber1) =
604 (*covBending)(hitNumber2, hitNumber1);
605 if (hitNumber1 == hitNumber2) {
606 // Diagonal elements: add contribution from position measurements
608 (*covBending)(hitNumber2, hitNumber1) =
609 (*covBending)(hitNumber2, hitNumber1) +
610 hit1->GetHitForRecPtr()->GetBendingReso2();
611 // and in non bending plane
612 (*covNonBending)(hitNumber2, hitNumber1) =
613 (*covNonBending)(hitNumber2, hitNumber1) +
614 hit1->GetHitForRecPtr()->GetNonBendingReso2();
617 // Non diagonal elements: symmetrization
619 (*covBending)(hitNumber1, hitNumber2) =
620 (*covBending)(hitNumber2, hitNumber1);
621 // and non bending plane
622 (*covNonBending)(hitNumber1, hitNumber2) =
623 (*covNonBending)(hitNumber2, hitNumber1);
625 } // for (hitNumber2 = hitNumber1;...
626 } // for (hitNumber1 = 0;...
628 // Inversion of covariance matrices
629 // with "mnvertLocal", local "mnvert" function of Minuit.
630 // One cannot use directly "mnvert" since "TVirtualFitter" does not know it.
631 // One will have to replace this local function by the right inversion function
632 // from a specialized Root package for symmetric positive definite matrices,
633 // when available!!!!
635 mnvertLocal(&((*covBending)(0,0)), numberOfHit, numberOfHit, numberOfHit,
637 Int_t ifailNonBending;
638 mnvertLocal(&((*covNonBending)(0,0)), numberOfHit, numberOfHit, numberOfHit,
641 // It would be worth trying to calculate the inverse of the covariance matrix
642 // only once per fit, since it cannot change much in principle,
643 // and it would save a lot of computing time !!!!
646 if ((ifailBending == 0) && (ifailNonBending == 0)) {
647 // with Multiple Scattering if inversion correct
648 for (hitNumber1 = 0; hitNumber1 < numberOfHit ; hitNumber1++) {
649 hit1 = (AliMUONTrackHit*) (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber1];
650 hbc1 = hit1->GetHitForRecPtr()->GetBendingCoor();
651 pbc1 = hit1->GetTrackParam()->GetBendingCoor();
652 hnbc1 = hit1->GetHitForRecPtr()->GetNonBendingCoor();
653 pnbc1 = hit1->GetTrackParam()->GetNonBendingCoor();
654 for (hitNumber2 = 0; hitNumber2 < numberOfHit; hitNumber2++) {
655 hit2 = (AliMUONTrackHit*)
656 (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber2];
657 hbc2 = hit2->GetHitForRecPtr()->GetBendingCoor();
658 pbc2 = hit2->GetTrackParam()->GetBendingCoor();
659 hnbc2 = hit2->GetHitForRecPtr()->GetNonBendingCoor();
660 pnbc2 = hit2->GetTrackParam()->GetNonBendingCoor();
662 ((*covBending)(hitNumber2, hitNumber1) *
663 (hbc1 - pbc1) * (hbc2 - pbc2)) +
664 ((*covNonBending)(hitNumber2, hitNumber1) *
665 (hnbc1 - pnbc1) * (hnbc2 - pnbc2));
669 // without Multiple Scattering if inversion impossible
670 for (hitNumber1 = 0; hitNumber1 < numberOfHit ; hitNumber1++) {
671 hit1 = (AliMUONTrackHit*) (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber1];
672 hbc1 = hit1->GetHitForRecPtr()->GetBendingCoor();
673 pbc1 = hit1->GetTrackParam()->GetBendingCoor();
674 hnbc1 = hit1->GetHitForRecPtr()->GetNonBendingCoor();
675 pnbc1 = hit1->GetTrackParam()->GetNonBendingCoor();
677 ((hbc1 - pbc1) * (hbc1 - pbc1) /
678 hit1->GetHitForRecPtr()->GetBendingReso2()) +
679 ((hnbc1 - pnbc1) * (hnbc1 - pnbc1) /
680 hit1->GetHitForRecPtr()->GetNonBendingReso2());
685 delete covNonBending;
689 Double_t MultipleScatteringAngle2(AliMUONTrackHit *TrackHit)
691 // Returns square of multiple Coulomb scattering angle
692 // at TrackHit pointed to by "TrackHit"
693 Double_t slopeBending, slopeNonBending, radiationLength, inverseBendingMomentum2, inverseTotalMomentum2;
694 Double_t varMultipleScatteringAngle;
695 AliMUONTrack *trackBeingFitted = (AliMUONTrack*) AliMUONTrack::Fitter()->GetObjectFit();
696 AliMUONTrackParam *param = TrackHit->GetTrackParam();
697 // Better implementation in AliMUONTrack class ????
698 slopeBending = param->GetBendingSlope();
699 slopeNonBending = param->GetNonBendingSlope();
700 // thickness in radiation length for the current track,
701 // taking local angle into account
703 trackBeingFitted->GetEventReconstructor()->GetChamberThicknessInX0() *
705 slopeBending * slopeBending + slopeNonBending * slopeNonBending);
706 inverseBendingMomentum2 =
707 param->GetInverseBendingMomentum() * param->GetInverseBendingMomentum();
708 inverseTotalMomentum2 =
709 inverseBendingMomentum2 * (1.0 + slopeBending * slopeBending) /
710 (1.0 + slopeBending *slopeBending + slopeNonBending * slopeNonBending);
711 varMultipleScatteringAngle = 0.0136 * (1.0 + 0.038 * TMath::Log(radiationLength));
712 // The velocity is assumed to be 1 !!!!
713 varMultipleScatteringAngle = inverseTotalMomentum2 * radiationLength *
714 varMultipleScatteringAngle * varMultipleScatteringAngle;
715 return varMultipleScatteringAngle;
718 //______________________________________________________________________________
719 void mnvertLocal(Double_t *a, Int_t l, Int_t, Int_t n, Int_t &ifail)
721 //*-*-*-*-*-*-*-*-*-*-*-*Inverts a symmetric matrix*-*-*-*-*-*-*-*-*-*-*-*-*
722 //*-* ==========================
723 //*-* inverts a symmetric matrix. matrix is first scaled to
724 //*-* have all ones on the diagonal (equivalent to change of units)
725 //*-* but no pivoting is done since matrix is positive-definite.
726 //*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
728 // taken from TMinuit package of Root (l>=n)
729 // fVERTs, fVERTq and fVERTpp changed to localVERTs, localVERTq and localVERTpp
730 // Double_t localVERTs[n], localVERTq[n], localVERTpp[n];
731 Double_t * localVERTs = new Double_t[n];
732 Double_t * localVERTq = new Double_t[n];
733 Double_t * localVERTpp = new Double_t[n];
734 // fMaxint changed to localMaxint
735 Int_t localMaxint = n;
737 /* System generated locals */
740 /* Local variables */
742 Int_t i, j, k, kp1, km1;
744 /* Parameter adjustments */
750 if (n < 1) goto L100;
751 if (n > localMaxint) goto L100;
752 //*-*- scale matrix by sqrt of diag elements
753 for (i = 1; i <= n; ++i) {
755 if (si <= 0) goto L100;
756 localVERTs[i-1] = 1 / TMath::Sqrt(si);
758 for (i = 1; i <= n; ++i) {
759 for (j = 1; j <= n; ++j) {
760 a[i + j*l] = a[i + j*l]*localVERTs[i-1]*localVERTs[j-1];
763 //*-*- . . . start main loop . . . .
764 for (i = 1; i <= n; ++i) {
766 //*-*- preparation for elimination step1
767 if (a[k + k*l] != 0) localVERTq[k-1] = 1 / a[k + k*l];
769 localVERTpp[k-1] = 1;
773 if (km1 < 0) goto L100;
774 else if (km1 == 0) goto L50;
777 for (j = 1; j <= km1; ++j) {
778 localVERTpp[j-1] = a[j + k*l];
779 localVERTq[j-1] = a[j + k*l]*localVERTq[k-1];
783 if (k - n < 0) goto L51;
784 else if (k - n == 0) goto L60;
787 for (j = kp1; j <= n; ++j) {
788 localVERTpp[j-1] = a[k + j*l];
789 localVERTq[j-1] = -a[k + j*l]*localVERTq[k-1];
792 //*-*- elimination proper
794 for (j = 1; j <= n; ++j) {
795 for (k = j; k <= n; ++k) { a[j + k*l] += localVERTpp[j-1]*localVERTq[k-1]; }
798 //*-*- elements of left diagonal and unscaling
799 for (j = 1; j <= n; ++j) {
800 for (k = 1; k <= j; ++k) {
801 a[k + j*l] = a[k + j*l]*localVERTs[k-1]*localVERTs[j-1];
802 a[j + k*l] = a[k + j*l];
809 //*-*- failure return