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 ///////////////////////////////////////////////////
20 // Reconstructed track
26 ///////////////////////////////////////////////////
28 #include <stdlib.h> // for exit()
30 #include <Riostream.h> // for cout
33 #include <TObjArray.h>
34 #include <TVirtualFitter.h>
36 #include "AliMUONEventReconstructor.h"
37 #include "AliMUONHitForRec.h"
38 #include "AliMUONSegment.h"
39 #include "AliMUONTrack.h"
40 #include "AliMUONTrackHit.h"
41 #include "AliMUONTriggerTrack.h"
42 #include "AliMUONConstants.h"
44 // Functions to be minimized with Minuit
45 void TrackChi2(Int_t &NParam, Double_t *Gradient, Double_t &Chi2, Double_t *Param, Int_t Flag);
46 void TrackChi2MCS(Int_t &NParam, Double_t *Gradient, Double_t &Chi2, Double_t *Param, Int_t Flag);
48 void mnvertLocal(Double_t* a, Int_t l, Int_t m, Int_t n, Int_t& ifail);
50 Double_t MultipleScatteringAngle2(AliMUONTrackHit *TrackHit);
52 ClassImp(AliMUONTrack) // Class implementation in ROOT context
54 TVirtualFitter* AliMUONTrack::fgFitter = NULL;
56 //__________________________________________________________________________
57 AliMUONTrack::AliMUONTrack()
60 // Default constructor
62 fEventReconstructor = 0;
63 fTrackHitsPtr = new TObjArray(10);
64 fTrackParamAtHit = new TClonesArray("AliMUONTrackParam",10);
67 //__________________________________________________________________________
68 AliMUONTrack::AliMUONTrack(AliMUONSegment* BegSegment, AliMUONSegment* EndSegment, AliMUONEventReconstructor* EventReconstructor)
71 // Constructor from two Segment's
72 fEventReconstructor = EventReconstructor; // link back to EventReconstructor
73 // memory allocation for the TObjArray of pointers to reconstructed TrackHit's
74 fTrackHitsPtr = new TObjArray(10);
76 AddSegment(BegSegment); // add hits from BegSegment
77 AddSegment(EndSegment); // add hits from EndSegment
78 fTrackHitsPtr->Sort(); // sort TrackHits according to increasing Z
79 SetTrackParamAtVertex(); // set track parameters at vertex
80 fTrackParamAtHit = new TClonesArray("AliMUONTrackParam",10);
81 // set fit conditions...
86 fMatchTrigger = kFALSE;
87 fChi2MatchTrigger = 0;
91 //__________________________________________________________________________
92 AliMUONTrack::AliMUONTrack(AliMUONSegment* Segment, AliMUONHitForRec* HitForRec, AliMUONEventReconstructor* EventReconstructor)
95 // Constructor from one Segment and one HitForRec
96 fEventReconstructor = EventReconstructor; // link back to EventReconstructor
97 // memory allocation for the TObjArray of pointers to reconstructed TrackHit's
98 fTrackHitsPtr = new TObjArray(10);
100 AddSegment(Segment); // add hits from Segment
101 AddHitForRec(HitForRec); // add HitForRec
102 fTrackHitsPtr->Sort(); // sort TrackHits according to increasing Z
103 SetTrackParamAtVertex(); // set track parameters at vertex
104 fTrackParamAtHit = new TClonesArray("AliMUONTrackParam",10);
105 // set fit conditions...
110 fMatchTrigger = kFALSE;
111 fChi2MatchTrigger = 0;
115 //__________________________________________________________________________
116 AliMUONTrack::~AliMUONTrack()
120 delete fTrackHitsPtr; // delete the TObjArray of pointers to TrackHit's
121 fTrackHitsPtr = NULL;
124 if (fTrackParamAtHit) {
125 // delete the TClonesArray of pointers to TrackParam
126 delete fTrackParamAtHit;
127 fTrackParamAtHit = NULL;
131 //__________________________________________________________________________
132 AliMUONTrack::AliMUONTrack (const AliMUONTrack& theMUONTrack)
133 : TObject(theMUONTrack)
135 //fEventReconstructor = new AliMUONEventReconstructor(*MUONTrack.fEventReconstructor);
137 // NO, because it would use dummy copy constructor
138 // and AliMUONTrack is not the owner of its EventReconstructor
139 fEventReconstructor = theMUONTrack.fEventReconstructor;
140 fTrackParamAtVertex = theMUONTrack.fTrackParamAtVertex;
142 // necessary to make a copy of the objects and not only the pointers in TObjArray.
143 fTrackHitsPtr = new TObjArray(10);
144 for (Int_t index = 0; index < (theMUONTrack.fTrackHitsPtr)->GetEntriesFast(); index++) {
145 AliMUONTrackHit *trackHit = new AliMUONTrackHit(*(AliMUONTrackHit*)(theMUONTrack.fTrackHitsPtr)->At(index));
146 fTrackHitsPtr->Add(trackHit);
149 // necessary to make a copy of the objects and not only the pointers in TClonesArray.
150 fTrackParamAtHit = new TClonesArray("AliMUONTrackParam",10);
151 for (Int_t index = 0; index < (theMUONTrack.fTrackParamAtHit)->GetEntriesFast(); index++) {
152 {new ((*fTrackParamAtHit)[fTrackParamAtHit->GetEntriesFast()])
153 AliMUONTrackParam(*(AliMUONTrackParam*)(theMUONTrack.fTrackParamAtHit)->At(index));}
156 fNTrackHits = theMUONTrack.fNTrackHits;
157 fFitMCS = theMUONTrack.fFitMCS;
158 fFitNParam = theMUONTrack.fFitNParam;
159 fFitFMin = theMUONTrack.fFitFMin;
160 fFitStart = theMUONTrack.fFitStart;
161 fMatchTrigger = theMUONTrack.fMatchTrigger;
162 fChi2MatchTrigger = theMUONTrack.fChi2MatchTrigger;
165 //__________________________________________________________________________
166 AliMUONTrack & AliMUONTrack::operator=(const AliMUONTrack& theMUONTrack)
169 // check assignement to self
170 if (this == &theMUONTrack)
173 // base class assignement
174 TObject::operator=(theMUONTrack);
176 // fEventReconstructor = new AliMUONEventReconstructor(*MUONTrack.fEventReconstructor); // is it right ?
177 // is it right ? NO because it would use dummy copy constructor
178 fEventReconstructor = theMUONTrack.fEventReconstructor;
179 fTrackParamAtVertex = theMUONTrack.fTrackParamAtVertex;
181 // necessary to make a copy of the objects and not only the pointers in TObjArray.
182 fTrackHitsPtr = new TObjArray(10);
183 for (Int_t index = 0; index < (theMUONTrack.fTrackHitsPtr)->GetEntriesFast(); index++) {
184 AliMUONTrackHit *trackHit = new AliMUONTrackHit(*(AliMUONTrackHit*)(theMUONTrack.fTrackHitsPtr)->At(index));
185 fTrackHitsPtr->Add(trackHit);
188 // necessary to make a copy of the objects and not only the pointers in TClonesArray.
189 fTrackParamAtHit = new TClonesArray("AliMUONTrackParam",10);
190 for (Int_t index = 0; index < (theMUONTrack.fTrackParamAtHit)->GetEntriesFast(); index++) {
191 {new ((*fTrackParamAtHit)[fTrackParamAtHit->GetEntriesFast()])
192 AliMUONTrackParam(*(AliMUONTrackParam*)(theMUONTrack.fTrackParamAtHit)->At(index));}
195 fNTrackHits = theMUONTrack.fNTrackHits;
196 fFitMCS = theMUONTrack.fFitMCS;
197 fFitNParam = theMUONTrack.fFitNParam;
198 fFitFMin = theMUONTrack.fFitFMin;
199 fFitStart = theMUONTrack.fFitStart;
200 fMatchTrigger = theMUONTrack.fMatchTrigger;
201 fChi2MatchTrigger = theMUONTrack.fChi2MatchTrigger;
206 //__________________________________________________________________________
207 void AliMUONTrack::Remove()
209 // Remove current track from array of tracks,
210 // and corresponding track hits from array of track hits.
211 // Compress the TClonesArray it belongs to.
212 AliMUONTrackHit *nextTrackHit;
213 AliMUONEventReconstructor *eventRec = this->fEventReconstructor;
214 TClonesArray *trackHitsPtr = eventRec->GetRecTrackHitsPtr();
215 // Loop over all track hits of track
216 AliMUONTrackHit *trackHit = (AliMUONTrackHit*) fTrackHitsPtr->First();
218 nextTrackHit = (AliMUONTrackHit*) fTrackHitsPtr->After(trackHit);
219 // Remove TrackHit from event TClonesArray.
220 // Destructor is called,
221 // hence links between HitForRec's and TrackHit's are updated
222 trackHitsPtr->Remove(trackHit);
223 trackHit = nextTrackHit;
225 // Remove the track from event TClonesArray
226 // Destructor is called,
227 // hence space for TObjArray of pointers to TrackHit's is freed
228 eventRec->GetRecTracksPtr()->Remove(this);
229 // Number of tracks decreased by 1
230 eventRec->SetNRecTracks(eventRec->GetNRecTracks() - 1);
231 // Compress event TClonesArray of Track's:
232 // this is essential to retrieve the TClonesArray afterwards
233 eventRec->GetRecTracksPtr()->Compress();
234 // Compress event TClonesArray of TrackHit's:
235 // this is probably also essential to retrieve the TClonesArray afterwards
236 trackHitsPtr->Compress();
239 //__________________________________________________________________________
240 void AliMUONTrack::SetFitMCS(Int_t FitMCS)
242 // Set multiple Coulomb scattering option for track fit "fFitMCS"
243 // from "FitMCS" argument: 0 without, 1 with
244 if ((FitMCS == 0) || (FitMCS == 1)) fFitMCS = FitMCS;
245 // better implementation with enum(with, without) ????
247 cout << "ERROR in AliMUONTrack::SetFitMCS(FitMCS)" << endl;
248 cout << "FitMCS = " << FitMCS << " is neither 0 nor 1" << endl;
254 //__________________________________________________________________________
255 void AliMUONTrack::SetFitNParam(Int_t FitNParam)
257 // Set number of parameters for track fit "fFitNParam" from "FitNParam":
258 // 3 for momentum, 5 for momentum and position
259 if ((FitNParam == 3) || (FitNParam == 5)) fFitNParam = FitNParam;
261 cout << "ERROR in AliMUONTrack::SetFitNParam(FitNParam)" << endl;
262 cout << "FitNParam = " << FitNParam << " is neither 3 nor 5" << endl;
268 //__________________________________________________________________________
269 void AliMUONTrack::SetFitStart(Int_t FitStart)
271 // Set multiple Coulomb scattering option for track fit "fFitStart"
272 // from "FitStart" argument: 0 without, 1 with
273 if ((FitStart == 0) || (FitStart == 1)) fFitStart = FitStart;
274 // better implementation with enum(vertex, firstHit) ????
276 cout << "ERROR in AliMUONTrack::SetFitStart(FitStart)" << endl;
277 cout << "FitStart = " << FitStart << " is neither 0 nor 1" << endl;
283 //__________________________________________________________________________
284 AliMUONTrackParam* AliMUONTrack::GetTrackParamAtFirstHit(void) const {
285 // Get pointer to TrackParamAtFirstHit
286 return ((AliMUONTrackHit*) (fTrackHitsPtr->First()))->GetTrackParam();}
288 //__________________________________________________________________________
289 void AliMUONTrack::RecursiveDump(void) const
291 // Recursive dump of AliMUONTrack, i.e. with dump of TrackHit's and HitForRec's
292 AliMUONTrackHit *trackHit;
293 AliMUONHitForRec *hitForRec;
294 cout << "Recursive dump of Track: " << this << endl;
297 for (Int_t trackHitIndex = 0; trackHitIndex < fNTrackHits; trackHitIndex++) {
298 trackHit = (AliMUONTrackHit*) ((*fTrackHitsPtr)[trackHitIndex]);
300 cout << "TrackHit: " << trackHit << " (index: " << trackHitIndex << ")" << endl;
302 hitForRec = trackHit->GetHitForRecPtr();
304 cout << "HitForRec: " << hitForRec << endl;
310 //__________________________________________________________________________
311 Int_t AliMUONTrack::HitsInCommon(AliMUONTrack* Track) const
313 // Returns the number of hits in common
314 // between the current track ("this")
315 // and the track pointed to by "Track".
316 Int_t hitsInCommon = 0;
317 AliMUONTrackHit *trackHit1, *trackHit2;
318 // Loop over hits of first track
319 trackHit1 = (AliMUONTrackHit*) this->GetTrackHitsPtr()->First();
321 // Loop over hits of second track
322 trackHit2 = (AliMUONTrackHit*) Track->GetTrackHitsPtr()->First();
324 // Increment "hitsInCommon" if both TrackHits point to the same HitForRec
325 if ( (trackHit1->GetHitForRecPtr()) ==
326 (trackHit2->GetHitForRecPtr()) ) hitsInCommon++;
327 trackHit2 = (AliMUONTrackHit*) Track->GetTrackHitsPtr()->After(trackHit2);
329 trackHit1 = (AliMUONTrackHit*) this->GetTrackHitsPtr()->After(trackHit1);
334 //__________________________________________________________________________
335 void AliMUONTrack::MatchTriggerTrack(TClonesArray *triggerTrackArray)
337 // Match this track with one trigger track if possible
338 AliMUONTrackParam trackParam;
339 AliMUONTriggerTrack *triggerTrack;
340 Double_t xTrack, yTrack, ySlopeTrack, dTrigTrackMin2, dTrigTrack2;
343 Double_t distSigma[3]={1,1,0.02}; // sigma of distributions (trigger-track) X,Y,slopeY
344 Double_t distTriggerTrack[3] = {0,0,0};
346 fMatchTrigger = kFALSE;
347 fChi2MatchTrigger = 0;
349 trackParam = *((AliMUONTrackParam*) fTrackParamAtHit->Last());
350 trackParam.ExtrapToZ(AliMUONConstants::DefaultChamberZ(10)); // extrap to 1st trigger chamber
352 nSigmaCut2 = fEventReconstructor->GetMaxSigma2Distance(); // nb of sigma**2 for cut
353 xTrack = trackParam.GetNonBendingCoor();
354 yTrack = trackParam.GetBendingCoor();
355 ySlopeTrack = trackParam.GetBendingSlope();
356 dTrigTrackMin2 = 999;
358 triggerTrack = (AliMUONTriggerTrack*) triggerTrackArray->First();
360 distTriggerTrack[0] = (triggerTrack->GetX11()-xTrack)/distSigma[0];
361 distTriggerTrack[1] = (triggerTrack->GetY11()-yTrack)/distSigma[1];
362 distTriggerTrack[2] = (TMath::Tan(triggerTrack->GetThetay())-ySlopeTrack)/distSigma[2];
364 for (Int_t iVar = 0; iVar < 3; iVar++)
365 dTrigTrack2 += distTriggerTrack[iVar]*distTriggerTrack[iVar];
366 if (dTrigTrack2 < dTrigTrackMin2 && dTrigTrack2 < nSigmaCut2) {
367 dTrigTrackMin2 = dTrigTrack2;
368 fMatchTrigger = kTRUE;
369 fChi2MatchTrigger = dTrigTrack2/3.; // Normalized Chi2, 3 variables (X,Y,slopeY)
371 triggerTrack = (AliMUONTriggerTrack*) triggerTrackArray->After(triggerTrack);
375 //__________________________________________________________________________
376 void AliMUONTrack::Fit()
378 // Fit the current track ("this"),
379 // with or without multiple Coulomb scattering according to "fFitMCS",
380 // with the number of parameters given by "fFitNParam"
381 // (3 if one keeps X and Y fixed in "TrackParam", 5 if one lets them vary),
382 // starting, according to "fFitStart",
383 // with track parameters at vertex or at the first TrackHit.
384 // "fFitMCS", "fFitNParam" and "fFitStart" have to be set before
385 // by calling the corresponding Set methods.
386 Double_t arg[1], benC, errorParam, invBenP, lower, nonBenC, upper, x, y;
388 AliMUONTrackParam *trackParam;
389 // Check if Minuit is initialized...
390 fgFitter = TVirtualFitter::Fitter(this); // add 3 or 5 for the maximum number of parameters ???
391 fgFitter->Clear(); // necessary ???? probably yes
392 // how to reset the printout number at every fit ????
393 // is there any risk to leave it like that ????
394 // how to go faster ???? choice of Minuit parameters like EDM ????
395 // choice of function to be minimized according to fFitMCS
396 if (fFitMCS == 0) fgFitter->SetFCN(TrackChi2);
397 else fgFitter->SetFCN(TrackChi2MCS);
398 // Switch off printout
400 fgFitter->ExecuteCommand("SET PRINT", arg, 1); // More printing !!!!
402 fgFitter->ExecuteCommand("SET NOW", arg, 0);
403 // Parameters according to "fFitStart"
404 // (should be a function to be used at every place where needed ????)
405 if (fFitStart == 0) trackParam = &fTrackParamAtVertex;
406 else trackParam = this->GetTrackParamAtFirstHit();
407 // set first 3 Minuit parameters
408 // could be tried with no limits for the search (min=max=0) ????
409 fgFitter->SetParameter(0, "InvBenP",
410 trackParam->GetInverseBendingMomentum(),
412 fgFitter->SetParameter(1, "BenS",
413 trackParam->GetBendingSlope(),
415 fgFitter->SetParameter(2, "NonBenS",
416 trackParam->GetNonBendingSlope(),
418 if (fFitNParam == 5) {
419 // set last 2 Minuit parameters
420 // mandatory limits in Bending to avoid NaN values of parameters
421 fgFitter->SetParameter(3, "X",
422 trackParam->GetNonBendingCoor(),
423 0.03, -500.0, 500.0);
424 // mandatory limits in non Bending to avoid NaN values of parameters
425 fgFitter->SetParameter(4, "Y",
426 trackParam->GetBendingCoor(),
427 0.10, -500.0, 500.0);
429 // search without gradient calculation in the function
430 fgFitter->ExecuteCommand("SET NOGRADIENT", arg, 0);
432 fgFitter->ExecuteCommand("MINIMIZE", arg, 0);
434 // fgFitter->ExecuteCommand("EXIT", arg, 0); // necessary ????
435 // get results into "invBenP", "benC", "nonBenC" ("x", "y")
436 fgFitter->GetParameter(0, parName, invBenP, errorParam, lower, upper);
437 fgFitter->GetParameter(1, parName, benC, errorParam, lower, upper);
438 fgFitter->GetParameter(2, parName, nonBenC, errorParam, lower, upper);
439 if (fFitNParam == 5) {
440 fgFitter->GetParameter(3, parName, x, errorParam, lower, upper);
441 fgFitter->GetParameter(4, parName, y, errorParam, lower, upper);
443 // result of the fit into track parameters
444 trackParam->SetInverseBendingMomentum(invBenP);
445 trackParam->SetBendingSlope(benC);
446 trackParam->SetNonBendingSlope(nonBenC);
447 if (fFitNParam == 5) {
448 trackParam->SetNonBendingCoor(x);
449 trackParam->SetBendingCoor(y);
451 // global result of the fit
452 Double_t fedm, errdef;
454 fgFitter->GetStats(fFitFMin, fedm, errdef, npari, nparx);
457 //__________________________________________________________________________
458 void AliMUONTrack::AddSegment(AliMUONSegment* Segment)
460 // Add Segment to the track
461 AddHitForRec(Segment->GetHitForRec1()); // 1st hit
462 AddHitForRec(Segment->GetHitForRec2()); // 2nd hit
465 //__________________________________________________________________________
466 void AliMUONTrack::AddHitForRec(AliMUONHitForRec* HitForRec)
468 // Add HitForRec to the track:
469 // actual TrackHit into TClonesArray of TrackHit's for the event;
470 // pointer to actual TrackHit in TObjArray of pointers to TrackHit's for the track
471 TClonesArray *recTrackHitsPtr = this->fEventReconstructor->GetRecTrackHitsPtr();
472 Int_t eventTrackHits = this->fEventReconstructor->GetNRecTrackHits();
474 AliMUONTrackHit* trackHit =
475 new ((*recTrackHitsPtr)[eventTrackHits]) AliMUONTrackHit(HitForRec);
476 this->fEventReconstructor->SetNRecTrackHits(eventTrackHits + 1);
478 fTrackHitsPtr->Add(trackHit);
482 //__________________________________________________________________________
483 void AliMUONTrack::SetTrackParamAtHit(Int_t indexHit, AliMUONTrackParam *TrackParam) const
485 // Set track parameters at TrackHit with index "indexHit"
486 // from the track parameters pointed to by "TrackParam".
487 //PH AliMUONTrackHit* trackHit = (AliMUONTrackHit*) ((*fTrackHitsPtr)[indexHit]);
488 AliMUONTrackHit* trackHit = (AliMUONTrackHit*) (fTrackHitsPtr->At(indexHit));
489 trackHit->SetTrackParam(TrackParam);
492 //__________________________________________________________________________
493 void AliMUONTrack::SetTrackParamAtVertex()
495 // Set track parameters at vertex.
496 // TrackHit's are assumed to be only in stations(1..) 4 and 5,
497 // and sorted according to increasing Z..
498 // Parameters are calculated from information in HitForRec's
499 // of first and last TrackHit's.
500 AliMUONTrackParam *trackParam =
501 &fTrackParamAtVertex; // pointer to track parameters
502 // Pointer to HitForRec of first TrackHit
503 AliMUONHitForRec *firstHit =
504 ((AliMUONTrackHit*) (fTrackHitsPtr->First()))->GetHitForRecPtr();
505 // Pointer to HitForRec of last TrackHit
506 AliMUONHitForRec *lastHit =
507 ((AliMUONTrackHit*) (fTrackHitsPtr->Last()))->GetHitForRecPtr();
508 // Z difference between first and last hits
509 Double_t deltaZ = firstHit->GetZ() - lastHit->GetZ();
510 // bending slope in stations(1..) 4 and 5
511 Double_t bendingSlope =
512 (firstHit->GetBendingCoor() - lastHit->GetBendingCoor()) / deltaZ;
513 trackParam->SetBendingSlope(bendingSlope);
515 Double_t impactParam =
516 firstHit->GetBendingCoor() - bendingSlope * firstHit->GetZ(); // same if from firstHit and lastHit ????
517 // signed bending momentum
518 Double_t signedBendingMomentum =
519 fEventReconstructor->GetBendingMomentumFromImpactParam(impactParam);
520 trackParam->SetInverseBendingMomentum(1.0 / signedBendingMomentum);
521 // bending slope at vertex
523 SetBendingSlope(bendingSlope +
524 impactParam / fEventReconstructor->GetSimpleBPosition());
526 Double_t nonBendingSlope =
527 (firstHit->GetNonBendingCoor() - lastHit->GetNonBendingCoor()) / deltaZ;
528 trackParam->SetNonBendingSlope(nonBendingSlope);
529 // vertex coordinates at (0,0,0)
530 trackParam->SetZ(0.0);
531 trackParam->SetBendingCoor(0.0);
532 trackParam->SetNonBendingCoor(0.0);
535 //__________________________________________________________________________
536 void TrackChi2(Int_t &NParam, Double_t * /*Gradient*/, Double_t &Chi2, Double_t *Param, Int_t /*Flag*/)
538 // Return the "Chi2" to be minimized with Minuit for track fitting,
539 // with "NParam" parameters
540 // and their current values in array pointed to by "Param".
541 // Assumes that the track hits are sorted according to increasing Z.
542 // Track parameters at each TrackHit are updated accordingly.
543 // Multiple Coulomb scattering is not taken into account
544 AliMUONTrack *trackBeingFitted;
545 AliMUONTrackHit* hit;
546 AliMUONTrackParam param1;
549 Chi2 = 0.0; // initialize Chi2
550 // copy of track parameters to be fitted
551 trackBeingFitted = (AliMUONTrack*) AliMUONTrack::Fitter()->GetObjectFit();
552 if (trackBeingFitted->GetFitStart() == 0)
553 param1 = *(trackBeingFitted->GetTrackParamAtVertex());
554 else param1 = *(trackBeingFitted->GetTrackParamAtFirstHit());
555 // Minuit parameters to be fitted into this copy
556 param1.SetInverseBendingMomentum(Param[0]);
557 param1.SetBendingSlope(Param[1]);
558 param1.SetNonBendingSlope(Param[2]);
560 param1.SetNonBendingCoor(Param[3]);
561 param1.SetBendingCoor(Param[4]);
563 // Follow track through all planes of track hits
564 for (hitNumber = 0; hitNumber < trackBeingFitted->GetNTrackHits(); hitNumber++) {
565 hit = (AliMUONTrackHit*) (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber];
566 zHit = hit->GetHitForRecPtr()->GetZ();
567 // do something special if 2 hits with same Z ????
568 // security against infinite loop ????
569 (¶m1)->ExtrapToZ(zHit); // extrapolation
570 hit->SetTrackParam(¶m1);
572 // done hit per hit, with hit resolution,
573 // and not with point and angle like in "reco_muon.F" !!!!
574 // Needs to add multiple scattering contribution ????
576 hit->GetHitForRecPtr()->GetNonBendingCoor() - (¶m1)->GetNonBendingCoor();
578 hit->GetHitForRecPtr()->GetBendingCoor() - (¶m1)->GetBendingCoor();
581 dX * dX / hit->GetHitForRecPtr()->GetNonBendingReso2() +
582 dY * dY / hit->GetHitForRecPtr()->GetBendingReso2();
586 //__________________________________________________________________________
587 void TrackChi2MCS(Int_t &NParam, Double_t * /*Gradient*/, Double_t &Chi2, Double_t *Param, Int_t /*Flag*/)
589 // Return the "Chi2" to be minimized with Minuit for track fitting,
590 // with "NParam" parameters
591 // and their current values in array pointed to by "Param".
592 // Assumes that the track hits are sorted according to increasing Z.
593 // Track parameters at each TrackHit are updated accordingly.
594 // Multiple Coulomb scattering is taken into account with covariance matrix.
595 AliMUONTrack *trackBeingFitted;
596 AliMUONTrackParam param1;
597 Chi2 = 0.0; // initialize Chi2
598 // copy of track parameters to be fitted
599 trackBeingFitted = (AliMUONTrack*) AliMUONTrack::Fitter()->GetObjectFit();
600 if (trackBeingFitted->GetFitStart() == 0)
601 param1 = *(trackBeingFitted->GetTrackParamAtVertex());
602 else param1 = *(trackBeingFitted->GetTrackParamAtFirstHit());
603 // Minuit parameters to be fitted into this copy
604 param1.SetInverseBendingMomentum(Param[0]);
605 param1.SetBendingSlope(Param[1]);
606 param1.SetNonBendingSlope(Param[2]);
608 param1.SetNonBendingCoor(Param[3]);
609 param1.SetBendingCoor(Param[4]);
612 AliMUONTrackHit *hit;
613 Int_t chCurrent, chPrev = 0, hitNumber, hitNumber1, hitNumber2, hitNumber3;
614 Double_t z, z1, z2, z3;
615 AliMUONTrackHit *hit1, *hit2, *hit3;
616 Double_t hbc1, hbc2, pbc1, pbc2;
617 Double_t hnbc1, hnbc2, pnbc1, pnbc2;
618 Int_t numberOfHit = trackBeingFitted->GetNTrackHits();
619 TMatrixD *covBending = new TMatrixD(numberOfHit, numberOfHit);
620 TMatrixD *covNonBending = new TMatrixD(numberOfHit, numberOfHit);
621 Double_t *msa2 = new Double_t[numberOfHit];
623 // Predicted coordinates and multiple scattering angles are first calculated
624 for (hitNumber = 0; hitNumber < numberOfHit; hitNumber++) {
625 hit = (AliMUONTrackHit*) (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber];
626 z = hit->GetHitForRecPtr()->GetZ();
627 // do something special if 2 hits with same Z ????
628 // security against infinite loop ????
629 (¶m1)->ExtrapToZ(z); // extrapolation
630 hit->SetTrackParam(¶m1);
631 // square of multiple scattering angle at current hit, with one chamber
632 msa2[hitNumber] = MultipleScatteringAngle2(hit);
633 // correction for eventual missing hits or multiple hits in a chamber,
634 // according to the number of chambers
635 // between the current hit and the previous one
636 chCurrent = hit->GetHitForRecPtr()->GetChamberNumber();
637 if (hitNumber > 0) msa2[hitNumber] = msa2[hitNumber] * (chCurrent - chPrev);
641 // Calculates the covariance matrix
642 for (hitNumber1 = 0; hitNumber1 < numberOfHit; hitNumber1++) {
643 hit1 = (AliMUONTrackHit*) (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber1];
644 z1 = hit1->GetHitForRecPtr()->GetZ();
645 for (hitNumber2 = hitNumber1; hitNumber2 < numberOfHit; hitNumber2++) {
646 hit2 = (AliMUONTrackHit*) (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber2];
647 z2 = hit2->GetHitForRecPtr()->GetZ();
648 // initialization to 0 (diagonal plus upper triangular part)
649 (*covBending)(hitNumber2, hitNumber1) = 0.0;
650 // contribution from multiple scattering in bending plane:
651 // loop over upstream hits
652 for (hitNumber3 = 0; hitNumber3 < hitNumber1; hitNumber3++) {
653 hit3 = (AliMUONTrackHit*)
654 (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber3];
655 z3 = hit3->GetHitForRecPtr()->GetZ();
656 (*covBending)(hitNumber2, hitNumber1) =
657 (*covBending)(hitNumber2, hitNumber1) +
658 ((z1 - z3) * (z2 - z3) * msa2[hitNumber3]);
660 // equal contribution from multiple scattering in non bending plane
661 (*covNonBending)(hitNumber2, hitNumber1) =
662 (*covBending)(hitNumber2, hitNumber1);
663 if (hitNumber1 == hitNumber2) {
664 // Diagonal elements: add contribution from position measurements
666 (*covBending)(hitNumber2, hitNumber1) =
667 (*covBending)(hitNumber2, hitNumber1) +
668 hit1->GetHitForRecPtr()->GetBendingReso2();
669 // and in non bending plane
670 (*covNonBending)(hitNumber2, hitNumber1) =
671 (*covNonBending)(hitNumber2, hitNumber1) +
672 hit1->GetHitForRecPtr()->GetNonBendingReso2();
675 // Non diagonal elements: symmetrization
677 (*covBending)(hitNumber1, hitNumber2) =
678 (*covBending)(hitNumber2, hitNumber1);
679 // and non bending plane
680 (*covNonBending)(hitNumber1, hitNumber2) =
681 (*covNonBending)(hitNumber2, hitNumber1);
683 } // for (hitNumber2 = hitNumber1;...
684 } // for (hitNumber1 = 0;...
686 // Inversion of covariance matrices
687 // with "mnvertLocal", local "mnvert" function of Minuit.
688 // One cannot use directly "mnvert" since "TVirtualFitter" does not know it.
689 // One will have to replace this local function by the right inversion function
690 // from a specialized Root package for symmetric positive definite matrices,
691 // when available!!!!
693 mnvertLocal(&((*covBending)(0,0)), numberOfHit, numberOfHit, numberOfHit,
695 Int_t ifailNonBending;
696 mnvertLocal(&((*covNonBending)(0,0)), numberOfHit, numberOfHit, numberOfHit,
699 // It would be worth trying to calculate the inverse of the covariance matrix
700 // only once per fit, since it cannot change much in principle,
701 // and it would save a lot of computing time !!!!
704 if ((ifailBending == 0) && (ifailNonBending == 0)) {
705 // with Multiple Scattering if inversion correct
706 for (hitNumber1 = 0; hitNumber1 < numberOfHit ; hitNumber1++) {
707 hit1 = (AliMUONTrackHit*) (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber1];
708 hbc1 = hit1->GetHitForRecPtr()->GetBendingCoor();
709 pbc1 = hit1->GetTrackParam()->GetBendingCoor();
710 hnbc1 = hit1->GetHitForRecPtr()->GetNonBendingCoor();
711 pnbc1 = hit1->GetTrackParam()->GetNonBendingCoor();
712 for (hitNumber2 = 0; hitNumber2 < numberOfHit; hitNumber2++) {
713 hit2 = (AliMUONTrackHit*)
714 (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber2];
715 hbc2 = hit2->GetHitForRecPtr()->GetBendingCoor();
716 pbc2 = hit2->GetTrackParam()->GetBendingCoor();
717 hnbc2 = hit2->GetHitForRecPtr()->GetNonBendingCoor();
718 pnbc2 = hit2->GetTrackParam()->GetNonBendingCoor();
720 ((*covBending)(hitNumber2, hitNumber1) *
721 (hbc1 - pbc1) * (hbc2 - pbc2)) +
722 ((*covNonBending)(hitNumber2, hitNumber1) *
723 (hnbc1 - pnbc1) * (hnbc2 - pnbc2));
727 // without Multiple Scattering if inversion impossible
728 for (hitNumber1 = 0; hitNumber1 < numberOfHit ; hitNumber1++) {
729 hit1 = (AliMUONTrackHit*) (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber1];
730 hbc1 = hit1->GetHitForRecPtr()->GetBendingCoor();
731 pbc1 = hit1->GetTrackParam()->GetBendingCoor();
732 hnbc1 = hit1->GetHitForRecPtr()->GetNonBendingCoor();
733 pnbc1 = hit1->GetTrackParam()->GetNonBendingCoor();
735 ((hbc1 - pbc1) * (hbc1 - pbc1) /
736 hit1->GetHitForRecPtr()->GetBendingReso2()) +
737 ((hnbc1 - pnbc1) * (hnbc1 - pnbc1) /
738 hit1->GetHitForRecPtr()->GetNonBendingReso2());
743 delete covNonBending;
747 Double_t MultipleScatteringAngle2(AliMUONTrackHit *TrackHit)
749 // Returns square of multiple Coulomb scattering angle
750 // at TrackHit pointed to by "TrackHit"
751 Double_t slopeBending, slopeNonBending, radiationLength, inverseBendingMomentum2, inverseTotalMomentum2;
752 Double_t varMultipleScatteringAngle;
753 AliMUONTrack *trackBeingFitted = (AliMUONTrack*) AliMUONTrack::Fitter()->GetObjectFit();
754 AliMUONTrackParam *param = TrackHit->GetTrackParam();
755 // Better implementation in AliMUONTrack class ????
756 slopeBending = param->GetBendingSlope();
757 slopeNonBending = param->GetNonBendingSlope();
758 // thickness in radiation length for the current track,
759 // taking local angle into account
761 trackBeingFitted->GetEventReconstructor()->GetChamberThicknessInX0() *
763 slopeBending * slopeBending + slopeNonBending * slopeNonBending);
764 inverseBendingMomentum2 =
765 param->GetInverseBendingMomentum() * param->GetInverseBendingMomentum();
766 inverseTotalMomentum2 =
767 inverseBendingMomentum2 * (1.0 + slopeBending * slopeBending) /
768 (1.0 + slopeBending *slopeBending + slopeNonBending * slopeNonBending);
769 varMultipleScatteringAngle = 0.0136 * (1.0 + 0.038 * TMath::Log(radiationLength));
770 // The velocity is assumed to be 1 !!!!
771 varMultipleScatteringAngle = inverseTotalMomentum2 * radiationLength *
772 varMultipleScatteringAngle * varMultipleScatteringAngle;
773 return varMultipleScatteringAngle;
776 //______________________________________________________________________________
777 void mnvertLocal(Double_t *a, Int_t l, Int_t, Int_t n, Int_t &ifail)
779 //*-*-*-*-*-*-*-*-*-*-*-*Inverts a symmetric matrix*-*-*-*-*-*-*-*-*-*-*-*-*
780 //*-* ==========================
781 //*-* inverts a symmetric matrix. matrix is first scaled to
782 //*-* have all ones on the diagonal (equivalent to change of units)
783 //*-* but no pivoting is done since matrix is positive-definite.
784 //*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
786 // taken from TMinuit package of Root (l>=n)
787 // fVERTs, fVERTq and fVERTpp changed to localVERTs, localVERTq and localVERTpp
788 // Double_t localVERTs[n], localVERTq[n], localVERTpp[n];
789 Double_t * localVERTs = new Double_t[n];
790 Double_t * localVERTq = new Double_t[n];
791 Double_t * localVERTpp = new Double_t[n];
792 // fMaxint changed to localMaxint
793 Int_t localMaxint = n;
795 /* System generated locals */
798 /* Local variables */
800 Int_t i, j, k, kp1, km1;
802 /* Parameter adjustments */
808 if (n < 1) goto L100;
809 if (n > localMaxint) goto L100;
810 //*-*- scale matrix by sqrt of diag elements
811 for (i = 1; i <= n; ++i) {
813 if (si <= 0) goto L100;
814 localVERTs[i-1] = 1 / TMath::Sqrt(si);
816 for (i = 1; i <= n; ++i) {
817 for (j = 1; j <= n; ++j) {
818 a[i + j*l] = a[i + j*l]*localVERTs[i-1]*localVERTs[j-1];
821 //*-*- . . . start main loop . . . .
822 for (i = 1; i <= n; ++i) {
824 //*-*- preparation for elimination step1
825 if (a[k + k*l] != 0) localVERTq[k-1] = 1 / a[k + k*l];
827 localVERTpp[k-1] = 1;
831 if (km1 < 0) goto L100;
832 else if (km1 == 0) goto L50;
835 for (j = 1; j <= km1; ++j) {
836 localVERTpp[j-1] = a[j + k*l];
837 localVERTq[j-1] = a[j + k*l]*localVERTq[k-1];
841 if (k - n < 0) goto L51;
842 else if (k - n == 0) goto L60;
845 for (j = kp1; j <= n; ++j) {
846 localVERTpp[j-1] = a[k + j*l];
847 localVERTq[j-1] = -a[k + j*l]*localVERTq[k-1];
850 //*-*- elimination proper
852 for (j = 1; j <= n; ++j) {
853 for (k = j; k <= n; ++k) { a[j + k*l] += localVERTpp[j-1]*localVERTq[k-1]; }
856 //*-*- elements of left diagonal and unscaling
857 for (j = 1; j <= n; ++j) {
858 for (k = 1; k <= j; ++k) {
859 a[k + j*l] = a[k + j*l]*localVERTs[k-1]*localVERTs[j-1];
860 a[j + k*l] = a[k + j*l];
867 //*-*- failure return