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 <Riostream.h> // for cout
29 #include <stdlib.h> // for exit()
31 #include <TClonesArray.h>
34 #include <TObjArray.h>
35 #include <TVirtualFitter.h>
37 #include "AliMUONEventReconstructor.h"
38 #include "AliMUONHitForRec.h"
39 #include "AliMUONSegment.h"
40 #include "AliMUONTrack.h"
41 #include "AliMUONTrackHit.h"
42 #include "AliMUONTriggerTrack.h"
43 #include "AliMUONConstants.h"
45 // Functions to be minimized with Minuit
46 void TrackChi2(Int_t &NParam, Double_t *Gradient, Double_t &Chi2, Double_t *Param, Int_t Flag);
47 void TrackChi2MCS(Int_t &NParam, Double_t *Gradient, Double_t &Chi2, Double_t *Param, Int_t Flag);
49 void mnvertLocal(Double_t* a, Int_t l, Int_t m, Int_t n, Int_t& ifail);
51 Double_t MultipleScatteringAngle2(AliMUONTrackHit *TrackHit);
53 ClassImp(AliMUONTrack) // Class implementation in ROOT context
55 TVirtualFitter* AliMUONTrack::fgFitter = NULL;
57 //__________________________________________________________________________
58 AliMUONTrack::AliMUONTrack()
60 // Default constructor
62 fEventReconstructor = 0;
64 fTrackParamAtHit = new TClonesArray("AliMUONTrackParam",10);
67 //__________________________________________________________________________
68 AliMUONTrack::AliMUONTrack(AliMUONSegment* BegSegment, AliMUONSegment* EndSegment, AliMUONEventReconstructor* EventReconstructor)
70 // Constructor from two Segment's
71 fEventReconstructor = EventReconstructor; // link back to EventReconstructor
72 // memory allocation for the TObjArray of pointers to reconstructed TrackHit's
73 fTrackHitsPtr = new TObjArray(10);
75 AddSegment(BegSegment); // add hits from BegSegment
76 AddSegment(EndSegment); // add hits from EndSegment
77 fTrackHitsPtr->Sort(); // sort TrackHits according to increasing Z
78 SetTrackParamAtVertex(); // set track parameters at vertex
79 fTrackParamAtHit = new TClonesArray("AliMUONTrackParam",10);
80 // set fit conditions...
85 fMatchTrigger = kFALSE;
86 fChi2MatchTrigger = 0;
90 //__________________________________________________________________________
91 AliMUONTrack::AliMUONTrack(AliMUONSegment* Segment, AliMUONHitForRec* HitForRec, AliMUONEventReconstructor* EventReconstructor)
93 // Constructor from one Segment and one HitForRec
94 fEventReconstructor = EventReconstructor; // link back to EventReconstructor
95 // memory allocation for the TObjArray of pointers to reconstructed TrackHit's
96 fTrackHitsPtr = new TObjArray(10);
98 AddSegment(Segment); // add hits from Segment
99 AddHitForRec(HitForRec); // add HitForRec
100 fTrackHitsPtr->Sort(); // sort TrackHits according to increasing Z
101 SetTrackParamAtVertex(); // set track parameters at vertex
102 fTrackParamAtHit = new TClonesArray("AliMUONTrackParam",10);
103 // set fit conditions...
108 fMatchTrigger = kFALSE;
109 fChi2MatchTrigger = 0;
113 //__________________________________________________________________________
114 AliMUONTrack::~AliMUONTrack()
118 delete fTrackHitsPtr; // delete the TObjArray of pointers to TrackHit's
119 fTrackHitsPtr = NULL;
122 if (fTrackParamAtHit) {
123 // delete the TClonesArray of pointers to TrackParam
124 delete fTrackParamAtHit;
125 fTrackParamAtHit = NULL;
129 //__________________________________________________________________________
130 AliMUONTrack::AliMUONTrack (const AliMUONTrack& MUONTrack):TObject(MUONTrack)
132 fEventReconstructor = new AliMUONEventReconstructor(*MUONTrack.fEventReconstructor); // is it right ?
133 fTrackParamAtVertex = MUONTrack.fTrackParamAtVertex;
134 fTrackHitsPtr = new TObjArray(*MUONTrack.fTrackHitsPtr); // is it right ?
135 fTrackParamAtHit = new TClonesArray(*MUONTrack.fTrackParamAtHit);
136 fNTrackHits = MUONTrack.fNTrackHits;
137 fFitMCS = MUONTrack.fFitMCS;
138 fFitNParam = MUONTrack.fFitNParam;
139 fFitFMin = MUONTrack.fFitFMin;
140 fFitStart = MUONTrack.fFitStart;
141 fMatchTrigger = MUONTrack.fMatchTrigger;
142 fChi2MatchTrigger = MUONTrack.fChi2MatchTrigger;
145 //__________________________________________________________________________
146 AliMUONTrack & AliMUONTrack::operator=(const AliMUONTrack& MUONTrack)
148 if (this == &MUONTrack)
151 fEventReconstructor = new AliMUONEventReconstructor(*MUONTrack.fEventReconstructor); // is it right ?
152 fTrackParamAtVertex = MUONTrack.fTrackParamAtVertex;
153 fTrackHitsPtr = new TObjArray(*MUONTrack.fTrackHitsPtr); // is it right ?
154 fTrackParamAtHit = new TClonesArray(*MUONTrack.fTrackParamAtHit);
155 fNTrackHits = MUONTrack.fNTrackHits;
156 fFitMCS = MUONTrack.fFitMCS;
157 fFitNParam = MUONTrack.fFitNParam;
158 fFitFMin = MUONTrack.fFitFMin;
159 fFitStart = MUONTrack.fFitStart;
160 fMatchTrigger = MUONTrack.fMatchTrigger;
161 fChi2MatchTrigger = MUONTrack.fChi2MatchTrigger;
165 //__________________________________________________________________________
166 void AliMUONTrack::Remove()
168 // Remove current track from array of tracks,
169 // and corresponding track hits from array of track hits.
170 // Compress the TClonesArray it belongs to.
171 AliMUONTrackHit *nextTrackHit;
172 AliMUONEventReconstructor *eventRec = this->fEventReconstructor;
173 TClonesArray *trackHitsPtr = eventRec->GetRecTrackHitsPtr();
174 // Loop over all track hits of track
175 AliMUONTrackHit *trackHit = (AliMUONTrackHit*) fTrackHitsPtr->First();
177 nextTrackHit = (AliMUONTrackHit*) fTrackHitsPtr->After(trackHit);
178 // Remove TrackHit from event TClonesArray.
179 // Destructor is called,
180 // hence links between HitForRec's and TrackHit's are updated
181 trackHitsPtr->Remove(trackHit);
182 trackHit = nextTrackHit;
184 // Remove the track from event TClonesArray
185 // Destructor is called,
186 // hence space for TObjArray of pointers to TrackHit's is freed
187 eventRec->GetRecTracksPtr()->Remove(this);
188 // Number of tracks decreased by 1
189 eventRec->SetNRecTracks(eventRec->GetNRecTracks() - 1);
190 // Compress event TClonesArray of Track's:
191 // this is essential to retrieve the TClonesArray afterwards
192 eventRec->GetRecTracksPtr()->Compress();
193 // Compress event TClonesArray of TrackHit's:
194 // this is probably also essential to retrieve the TClonesArray afterwards
195 trackHitsPtr->Compress();
198 //__________________________________________________________________________
199 void AliMUONTrack::SetFitMCS(Int_t FitMCS)
201 // Set multiple Coulomb scattering option for track fit "fFitMCS"
202 // from "FitMCS" argument: 0 without, 1 with
203 if ((FitMCS == 0) || (FitMCS == 1)) fFitMCS = FitMCS;
204 // better implementation with enum(with, without) ????
206 cout << "ERROR in AliMUONTrack::SetFitMCS(FitMCS)" << endl;
207 cout << "FitMCS = " << FitMCS << " is neither 0 nor 1" << endl;
213 //__________________________________________________________________________
214 void AliMUONTrack::SetFitNParam(Int_t FitNParam)
216 // Set number of parameters for track fit "fFitNParam" from "FitNParam":
217 // 3 for momentum, 5 for momentum and position
218 if ((FitNParam == 3) || (FitNParam == 5)) fFitNParam = FitNParam;
220 cout << "ERROR in AliMUONTrack::SetFitNParam(FitNParam)" << endl;
221 cout << "FitNParam = " << FitNParam << " is neither 3 nor 5" << endl;
227 //__________________________________________________________________________
228 void AliMUONTrack::SetFitStart(Int_t FitStart)
230 // Set multiple Coulomb scattering option for track fit "fFitStart"
231 // from "FitStart" argument: 0 without, 1 with
232 if ((FitStart == 0) || (FitStart == 1)) fFitStart = FitStart;
233 // better implementation with enum(vertex, firstHit) ????
235 cout << "ERROR in AliMUONTrack::SetFitStart(FitStart)" << endl;
236 cout << "FitStart = " << FitStart << " is neither 0 nor 1" << endl;
242 //__________________________________________________________________________
243 AliMUONTrackParam* AliMUONTrack::GetTrackParamAtFirstHit(void) const {
244 // Get pointer to TrackParamAtFirstHit
245 return ((AliMUONTrackHit*) (fTrackHitsPtr->First()))->GetTrackParam();}
247 //__________________________________________________________________________
248 void AliMUONTrack::RecursiveDump(void) const
250 // Recursive dump of AliMUONTrack, i.e. with dump of TrackHit's and HitForRec's
251 AliMUONTrackHit *trackHit;
252 AliMUONHitForRec *hitForRec;
253 cout << "Recursive dump of Track: " << this << endl;
256 for (Int_t trackHitIndex = 0; trackHitIndex < fNTrackHits; trackHitIndex++) {
257 trackHit = (AliMUONTrackHit*) ((*fTrackHitsPtr)[trackHitIndex]);
259 cout << "TrackHit: " << trackHit << " (index: " << trackHitIndex << ")" << endl;
261 hitForRec = trackHit->GetHitForRecPtr();
263 cout << "HitForRec: " << hitForRec << endl;
269 //__________________________________________________________________________
270 Int_t AliMUONTrack::HitsInCommon(AliMUONTrack* Track)
272 // Returns the number of hits in common
273 // between the current track ("this")
274 // and the track pointed to by "Track".
275 Int_t hitsInCommon = 0;
276 AliMUONTrackHit *trackHit1, *trackHit2;
277 // Loop over hits of first track
278 trackHit1 = (AliMUONTrackHit*) this->GetTrackHitsPtr()->First();
280 // Loop over hits of second track
281 trackHit2 = (AliMUONTrackHit*) Track->GetTrackHitsPtr()->First();
283 // Increment "hitsInCommon" if both TrackHits point to the same HitForRec
284 if ( (trackHit1->GetHitForRecPtr()) ==
285 (trackHit2->GetHitForRecPtr()) ) hitsInCommon++;
286 trackHit2 = (AliMUONTrackHit*) Track->GetTrackHitsPtr()->After(trackHit2);
288 trackHit1 = (AliMUONTrackHit*) this->GetTrackHitsPtr()->After(trackHit1);
293 //__________________________________________________________________________
294 void AliMUONTrack::MatchTriggerTrack(TClonesArray *triggerTrackArray)
296 // Match this track with one trigger track if possible
297 AliMUONTrackParam *trackParam;
298 AliMUONTriggerTrack *triggerTrack;
299 Double_t xTrack, yTrack, ySlopeTrack, dTrigTrackMin2, dTrigTrack2;
302 Double_t distSigma[3]={1,1,0.02}; // sigma of distributions (trigger-track) X,Y,slopeY
303 Double_t distTriggerTrack[3] = {0,0,0};
305 fMatchTrigger = kFALSE;
306 fChi2MatchTrigger = 0;
308 trackParam = (AliMUONTrackParam*) fTrackParamAtHit->Last();
309 trackParam->ExtrapToZ(AliMUONConstants::DefaultChamberZ(10)); // extrap to 1st trigger chamber
311 nSigmaCut2 = fEventReconstructor->GetMaxSigma2Distance(); // nb of sigma**2 for cut
312 xTrack = trackParam->GetNonBendingCoor();
313 yTrack = trackParam->GetBendingCoor();
314 ySlopeTrack = trackParam->GetBendingSlope();
315 dTrigTrackMin2 = 999;
317 triggerTrack = (AliMUONTriggerTrack*) triggerTrackArray->First();
319 distTriggerTrack[0] = (triggerTrack->GetX11()-xTrack)/distSigma[0];
320 distTriggerTrack[1] = (triggerTrack->GetY11()-yTrack)/distSigma[1];
321 distTriggerTrack[2] = (TMath::Tan(triggerTrack->GetThetay())-ySlopeTrack)/distSigma[2];
323 for (Int_t iVar = 0; iVar < 3; iVar++)
324 dTrigTrack2 += distTriggerTrack[iVar]*distTriggerTrack[iVar];
325 if (dTrigTrack2 < dTrigTrackMin2 && dTrigTrack2 < nSigmaCut2) {
326 dTrigTrackMin2 = dTrigTrack2;
327 fMatchTrigger = kTRUE;
328 fChi2MatchTrigger = dTrigTrack2/3.; // Normalized Chi2, 3 variables (X,Y,slopeY)
330 triggerTrack = (AliMUONTriggerTrack*) triggerTrackArray->After(triggerTrack);
334 //__________________________________________________________________________
335 void AliMUONTrack::Fit()
337 // Fit the current track ("this"),
338 // with or without multiple Coulomb scattering according to "fFitMCS",
339 // with the number of parameters given by "fFitNParam"
340 // (3 if one keeps X and Y fixed in "TrackParam", 5 if one lets them vary),
341 // starting, according to "fFitStart",
342 // with track parameters at vertex or at the first TrackHit.
343 // "fFitMCS", "fFitNParam" and "fFitStart" have to be set before
344 // by calling the corresponding Set methods.
345 Double_t arg[1], benC, errorParam, invBenP, lower, nonBenC, upper, x, y;
347 AliMUONTrackParam *trackParam;
348 // Check if Minuit is initialized...
349 fgFitter = TVirtualFitter::Fitter(this); // add 3 or 5 for the maximum number of parameters ???
350 fgFitter->Clear(); // necessary ???? probably yes
351 // how to reset the printout number at every fit ????
352 // is there any risk to leave it like that ????
353 // how to go faster ???? choice of Minuit parameters like EDM ????
354 // choice of function to be minimized according to fFitMCS
355 if (fFitMCS == 0) fgFitter->SetFCN(TrackChi2);
356 else fgFitter->SetFCN(TrackChi2MCS);
357 // Switch off printout
359 fgFitter->ExecuteCommand("SET PRINT", arg, 1); // More printing !!!!
361 fgFitter->ExecuteCommand("SET NOW", arg, 0);
362 // Parameters according to "fFitStart"
363 // (should be a function to be used at every place where needed ????)
364 if (fFitStart == 0) trackParam = &fTrackParamAtVertex;
365 else trackParam = this->GetTrackParamAtFirstHit();
366 // set first 3 Minuit parameters
367 // could be tried with no limits for the search (min=max=0) ????
368 fgFitter->SetParameter(0, "InvBenP",
369 trackParam->GetInverseBendingMomentum(),
371 fgFitter->SetParameter(1, "BenS",
372 trackParam->GetBendingSlope(),
374 fgFitter->SetParameter(2, "NonBenS",
375 trackParam->GetNonBendingSlope(),
377 if (fFitNParam == 5) {
378 // set last 2 Minuit parameters
379 // mandatory limits in Bending to avoid NaN values of parameters
380 fgFitter->SetParameter(3, "X",
381 trackParam->GetNonBendingCoor(),
382 0.03, -500.0, 500.0);
383 // mandatory limits in non Bending to avoid NaN values of parameters
384 fgFitter->SetParameter(4, "Y",
385 trackParam->GetBendingCoor(),
386 0.10, -500.0, 500.0);
388 // search without gradient calculation in the function
389 fgFitter->ExecuteCommand("SET NOGRADIENT", arg, 0);
391 fgFitter->ExecuteCommand("MINIMIZE", arg, 0);
393 // fgFitter->ExecuteCommand("EXIT", arg, 0); // necessary ????
394 // get results into "invBenP", "benC", "nonBenC" ("x", "y")
395 fgFitter->GetParameter(0, parName, invBenP, errorParam, lower, upper);
396 fgFitter->GetParameter(1, parName, benC, errorParam, lower, upper);
397 fgFitter->GetParameter(2, parName, nonBenC, errorParam, lower, upper);
398 if (fFitNParam == 5) {
399 fgFitter->GetParameter(3, parName, x, errorParam, lower, upper);
400 fgFitter->GetParameter(4, parName, y, errorParam, lower, upper);
402 // result of the fit into track parameters
403 trackParam->SetInverseBendingMomentum(invBenP);
404 trackParam->SetBendingSlope(benC);
405 trackParam->SetNonBendingSlope(nonBenC);
406 if (fFitNParam == 5) {
407 trackParam->SetNonBendingCoor(x);
408 trackParam->SetBendingCoor(y);
410 // global result of the fit
411 Double_t fedm, errdef;
413 fgFitter->GetStats(fFitFMin, fedm, errdef, npari, nparx);
416 //__________________________________________________________________________
417 void AliMUONTrack::AddSegment(AliMUONSegment* Segment)
419 // Add Segment to the track
420 AddHitForRec(Segment->GetHitForRec1()); // 1st hit
421 AddHitForRec(Segment->GetHitForRec2()); // 2nd hit
424 //__________________________________________________________________________
425 void AliMUONTrack::AddHitForRec(AliMUONHitForRec* HitForRec)
427 // Add HitForRec to the track:
428 // actual TrackHit into TClonesArray of TrackHit's for the event;
429 // pointer to actual TrackHit in TObjArray of pointers to TrackHit's for the track
430 TClonesArray *recTrackHitsPtr = this->fEventReconstructor->GetRecTrackHitsPtr();
431 Int_t eventTrackHits = this->fEventReconstructor->GetNRecTrackHits();
433 AliMUONTrackHit* trackHit =
434 new ((*recTrackHitsPtr)[eventTrackHits]) AliMUONTrackHit(HitForRec);
435 this->fEventReconstructor->SetNRecTrackHits(eventTrackHits + 1);
437 fTrackHitsPtr->Add(trackHit);
441 //__________________________________________________________________________
442 void AliMUONTrack::SetTrackParamAtHit(Int_t indexHit, AliMUONTrackParam *TrackParam) const
444 // Set track parameters at TrackHit with index "indexHit"
445 // from the track parameters pointed to by "TrackParam".
446 //PH AliMUONTrackHit* trackHit = (AliMUONTrackHit*) ((*fTrackHitsPtr)[indexHit]);
447 AliMUONTrackHit* trackHit = (AliMUONTrackHit*) (fTrackHitsPtr->At(indexHit));
448 trackHit->SetTrackParam(TrackParam);
451 //__________________________________________________________________________
452 void AliMUONTrack::SetTrackParamAtVertex()
454 // Set track parameters at vertex.
455 // TrackHit's are assumed to be only in stations(1..) 4 and 5,
456 // and sorted according to increasing Z..
457 // Parameters are calculated from information in HitForRec's
458 // of first and last TrackHit's.
459 AliMUONTrackParam *trackParam =
460 &fTrackParamAtVertex; // pointer to track parameters
461 // Pointer to HitForRec of first TrackHit
462 AliMUONHitForRec *firstHit =
463 ((AliMUONTrackHit*) (fTrackHitsPtr->First()))->GetHitForRecPtr();
464 // Pointer to HitForRec of last TrackHit
465 AliMUONHitForRec *lastHit =
466 ((AliMUONTrackHit*) (fTrackHitsPtr->Last()))->GetHitForRecPtr();
467 // Z difference between first and last hits
468 Double_t deltaZ = firstHit->GetZ() - lastHit->GetZ();
469 // bending slope in stations(1..) 4 and 5
470 Double_t bendingSlope =
471 (firstHit->GetBendingCoor() - lastHit->GetBendingCoor()) / deltaZ;
472 trackParam->SetBendingSlope(bendingSlope);
474 Double_t impactParam =
475 firstHit->GetBendingCoor() - bendingSlope * firstHit->GetZ(); // same if from firstHit and lastHit ????
476 // signed bending momentum
477 Double_t signedBendingMomentum =
478 fEventReconstructor->GetBendingMomentumFromImpactParam(impactParam);
479 trackParam->SetInverseBendingMomentum(1.0 / signedBendingMomentum);
480 // bending slope at vertex
482 SetBendingSlope(bendingSlope +
483 impactParam / fEventReconstructor->GetSimpleBPosition());
485 Double_t nonBendingSlope =
486 (firstHit->GetNonBendingCoor() - lastHit->GetNonBendingCoor()) / deltaZ;
487 trackParam->SetNonBendingSlope(nonBendingSlope);
488 // vertex coordinates at (0,0,0)
489 trackParam->SetZ(0.0);
490 trackParam->SetBendingCoor(0.0);
491 trackParam->SetNonBendingCoor(0.0);
494 //__________________________________________________________________________
495 void TrackChi2(Int_t &NParam, Double_t * /*Gradient*/, Double_t &Chi2, Double_t *Param, Int_t /*Flag*/)
497 // Return the "Chi2" to be minimized with Minuit for track fitting,
498 // with "NParam" parameters
499 // and their current values in array pointed to by "Param".
500 // Assumes that the track hits are sorted according to increasing Z.
501 // Track parameters at each TrackHit are updated accordingly.
502 // Multiple Coulomb scattering is not taken into account
503 AliMUONTrack *trackBeingFitted;
504 AliMUONTrackHit* hit;
505 AliMUONTrackParam param1;
508 Chi2 = 0.0; // initialize Chi2
509 // copy of track parameters to be fitted
510 trackBeingFitted = (AliMUONTrack*) AliMUONTrack::Fitter()->GetObjectFit();
511 if (trackBeingFitted->GetFitStart() == 0)
512 param1 = *(trackBeingFitted->GetTrackParamAtVertex());
513 else param1 = *(trackBeingFitted->GetTrackParamAtFirstHit());
514 // Minuit parameters to be fitted into this copy
515 param1.SetInverseBendingMomentum(Param[0]);
516 param1.SetBendingSlope(Param[1]);
517 param1.SetNonBendingSlope(Param[2]);
519 param1.SetNonBendingCoor(Param[3]);
520 param1.SetBendingCoor(Param[4]);
522 // Follow track through all planes of track hits
523 for (hitNumber = 0; hitNumber < trackBeingFitted->GetNTrackHits(); hitNumber++) {
524 hit = (AliMUONTrackHit*) (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber];
525 zHit = hit->GetHitForRecPtr()->GetZ();
526 // do something special if 2 hits with same Z ????
527 // security against infinite loop ????
528 (¶m1)->ExtrapToZ(zHit); // extrapolation
529 hit->SetTrackParam(¶m1);
531 // done hit per hit, with hit resolution,
532 // and not with point and angle like in "reco_muon.F" !!!!
533 // Needs to add multiple scattering contribution ????
535 hit->GetHitForRecPtr()->GetNonBendingCoor() - (¶m1)->GetNonBendingCoor();
537 hit->GetHitForRecPtr()->GetBendingCoor() - (¶m1)->GetBendingCoor();
540 dX * dX / hit->GetHitForRecPtr()->GetNonBendingReso2() +
541 dY * dY / hit->GetHitForRecPtr()->GetBendingReso2();
545 //__________________________________________________________________________
546 void TrackChi2MCS(Int_t &NParam, Double_t * /*Gradient*/, Double_t &Chi2, Double_t *Param, Int_t /*Flag*/)
548 // Return the "Chi2" to be minimized with Minuit for track fitting,
549 // with "NParam" parameters
550 // and their current values in array pointed to by "Param".
551 // Assumes that the track hits are sorted according to increasing Z.
552 // Track parameters at each TrackHit are updated accordingly.
553 // Multiple Coulomb scattering is taken into account with covariance matrix.
554 AliMUONTrack *trackBeingFitted;
555 AliMUONTrackParam param1;
556 Chi2 = 0.0; // initialize Chi2
557 // copy of track parameters to be fitted
558 trackBeingFitted = (AliMUONTrack*) AliMUONTrack::Fitter()->GetObjectFit();
559 if (trackBeingFitted->GetFitStart() == 0)
560 param1 = *(trackBeingFitted->GetTrackParamAtVertex());
561 else param1 = *(trackBeingFitted->GetTrackParamAtFirstHit());
562 // Minuit parameters to be fitted into this copy
563 param1.SetInverseBendingMomentum(Param[0]);
564 param1.SetBendingSlope(Param[1]);
565 param1.SetNonBendingSlope(Param[2]);
567 param1.SetNonBendingCoor(Param[3]);
568 param1.SetBendingCoor(Param[4]);
571 AliMUONTrackHit *hit;
572 Int_t chCurrent, chPrev = 0, hitNumber, hitNumber1, hitNumber2, hitNumber3;
573 Double_t z, z1, z2, z3;
574 AliMUONTrackHit *hit1, *hit2, *hit3;
575 Double_t hbc1, hbc2, pbc1, pbc2;
576 Double_t hnbc1, hnbc2, pnbc1, pnbc2;
577 Int_t numberOfHit = trackBeingFitted->GetNTrackHits();
578 TMatrixD *covBending = new TMatrixD(numberOfHit, numberOfHit);
579 TMatrixD *covNonBending = new TMatrixD(numberOfHit, numberOfHit);
580 Double_t *msa2 = new Double_t[numberOfHit];
582 // Predicted coordinates and multiple scattering angles are first calculated
583 for (hitNumber = 0; hitNumber < numberOfHit; hitNumber++) {
584 hit = (AliMUONTrackHit*) (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber];
585 z = hit->GetHitForRecPtr()->GetZ();
586 // do something special if 2 hits with same Z ????
587 // security against infinite loop ????
588 (¶m1)->ExtrapToZ(z); // extrapolation
589 hit->SetTrackParam(¶m1);
590 // square of multiple scattering angle at current hit, with one chamber
591 msa2[hitNumber] = MultipleScatteringAngle2(hit);
592 // correction for eventual missing hits or multiple hits in a chamber,
593 // according to the number of chambers
594 // between the current hit and the previous one
595 chCurrent = hit->GetHitForRecPtr()->GetChamberNumber();
596 if (hitNumber > 0) msa2[hitNumber] = msa2[hitNumber] * (chCurrent - chPrev);
600 // Calculates the covariance matrix
601 for (hitNumber1 = 0; hitNumber1 < numberOfHit; hitNumber1++) {
602 hit1 = (AliMUONTrackHit*) (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber1];
603 z1 = hit1->GetHitForRecPtr()->GetZ();
604 for (hitNumber2 = hitNumber1; hitNumber2 < numberOfHit; hitNumber2++) {
605 hit2 = (AliMUONTrackHit*) (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber2];
606 z2 = hit2->GetHitForRecPtr()->GetZ();
607 // initialization to 0 (diagonal plus upper triangular part)
608 (*covBending)(hitNumber2, hitNumber1) = 0.0;
609 // contribution from multiple scattering in bending plane:
610 // loop over upstream hits
611 for (hitNumber3 = 0; hitNumber3 < hitNumber1; hitNumber3++) {
612 hit3 = (AliMUONTrackHit*)
613 (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber3];
614 z3 = hit3->GetHitForRecPtr()->GetZ();
615 (*covBending)(hitNumber2, hitNumber1) =
616 (*covBending)(hitNumber2, hitNumber1) +
617 ((z1 - z3) * (z2 - z3) * msa2[hitNumber3]);
619 // equal contribution from multiple scattering in non bending plane
620 (*covNonBending)(hitNumber2, hitNumber1) =
621 (*covBending)(hitNumber2, hitNumber1);
622 if (hitNumber1 == hitNumber2) {
623 // Diagonal elements: add contribution from position measurements
625 (*covBending)(hitNumber2, hitNumber1) =
626 (*covBending)(hitNumber2, hitNumber1) +
627 hit1->GetHitForRecPtr()->GetBendingReso2();
628 // and in non bending plane
629 (*covNonBending)(hitNumber2, hitNumber1) =
630 (*covNonBending)(hitNumber2, hitNumber1) +
631 hit1->GetHitForRecPtr()->GetNonBendingReso2();
634 // Non diagonal elements: symmetrization
636 (*covBending)(hitNumber1, hitNumber2) =
637 (*covBending)(hitNumber2, hitNumber1);
638 // and non bending plane
639 (*covNonBending)(hitNumber1, hitNumber2) =
640 (*covNonBending)(hitNumber2, hitNumber1);
642 } // for (hitNumber2 = hitNumber1;...
643 } // for (hitNumber1 = 0;...
645 // Inversion of covariance matrices
646 // with "mnvertLocal", local "mnvert" function of Minuit.
647 // One cannot use directly "mnvert" since "TVirtualFitter" does not know it.
648 // One will have to replace this local function by the right inversion function
649 // from a specialized Root package for symmetric positive definite matrices,
650 // when available!!!!
652 mnvertLocal(&((*covBending)(0,0)), numberOfHit, numberOfHit, numberOfHit,
654 Int_t ifailNonBending;
655 mnvertLocal(&((*covNonBending)(0,0)), numberOfHit, numberOfHit, numberOfHit,
658 // It would be worth trying to calculate the inverse of the covariance matrix
659 // only once per fit, since it cannot change much in principle,
660 // and it would save a lot of computing time !!!!
663 if ((ifailBending == 0) && (ifailNonBending == 0)) {
664 // with Multiple Scattering if inversion correct
665 for (hitNumber1 = 0; hitNumber1 < numberOfHit ; hitNumber1++) {
666 hit1 = (AliMUONTrackHit*) (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber1];
667 hbc1 = hit1->GetHitForRecPtr()->GetBendingCoor();
668 pbc1 = hit1->GetTrackParam()->GetBendingCoor();
669 hnbc1 = hit1->GetHitForRecPtr()->GetNonBendingCoor();
670 pnbc1 = hit1->GetTrackParam()->GetNonBendingCoor();
671 for (hitNumber2 = 0; hitNumber2 < numberOfHit; hitNumber2++) {
672 hit2 = (AliMUONTrackHit*)
673 (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber2];
674 hbc2 = hit2->GetHitForRecPtr()->GetBendingCoor();
675 pbc2 = hit2->GetTrackParam()->GetBendingCoor();
676 hnbc2 = hit2->GetHitForRecPtr()->GetNonBendingCoor();
677 pnbc2 = hit2->GetTrackParam()->GetNonBendingCoor();
679 ((*covBending)(hitNumber2, hitNumber1) *
680 (hbc1 - pbc1) * (hbc2 - pbc2)) +
681 ((*covNonBending)(hitNumber2, hitNumber1) *
682 (hnbc1 - pnbc1) * (hnbc2 - pnbc2));
686 // without Multiple Scattering if inversion impossible
687 for (hitNumber1 = 0; hitNumber1 < numberOfHit ; hitNumber1++) {
688 hit1 = (AliMUONTrackHit*) (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber1];
689 hbc1 = hit1->GetHitForRecPtr()->GetBendingCoor();
690 pbc1 = hit1->GetTrackParam()->GetBendingCoor();
691 hnbc1 = hit1->GetHitForRecPtr()->GetNonBendingCoor();
692 pnbc1 = hit1->GetTrackParam()->GetNonBendingCoor();
694 ((hbc1 - pbc1) * (hbc1 - pbc1) /
695 hit1->GetHitForRecPtr()->GetBendingReso2()) +
696 ((hnbc1 - pnbc1) * (hnbc1 - pnbc1) /
697 hit1->GetHitForRecPtr()->GetNonBendingReso2());
702 delete covNonBending;
706 Double_t MultipleScatteringAngle2(AliMUONTrackHit *TrackHit)
708 // Returns square of multiple Coulomb scattering angle
709 // at TrackHit pointed to by "TrackHit"
710 Double_t slopeBending, slopeNonBending, radiationLength, inverseBendingMomentum2, inverseTotalMomentum2;
711 Double_t varMultipleScatteringAngle;
712 AliMUONTrack *trackBeingFitted = (AliMUONTrack*) AliMUONTrack::Fitter()->GetObjectFit();
713 AliMUONTrackParam *param = TrackHit->GetTrackParam();
714 // Better implementation in AliMUONTrack class ????
715 slopeBending = param->GetBendingSlope();
716 slopeNonBending = param->GetNonBendingSlope();
717 // thickness in radiation length for the current track,
718 // taking local angle into account
720 trackBeingFitted->GetEventReconstructor()->GetChamberThicknessInX0() *
722 slopeBending * slopeBending + slopeNonBending * slopeNonBending);
723 inverseBendingMomentum2 =
724 param->GetInverseBendingMomentum() * param->GetInverseBendingMomentum();
725 inverseTotalMomentum2 =
726 inverseBendingMomentum2 * (1.0 + slopeBending * slopeBending) /
727 (1.0 + slopeBending *slopeBending + slopeNonBending * slopeNonBending);
728 varMultipleScatteringAngle = 0.0136 * (1.0 + 0.038 * TMath::Log(radiationLength));
729 // The velocity is assumed to be 1 !!!!
730 varMultipleScatteringAngle = inverseTotalMomentum2 * radiationLength *
731 varMultipleScatteringAngle * varMultipleScatteringAngle;
732 return varMultipleScatteringAngle;
735 //______________________________________________________________________________
736 void mnvertLocal(Double_t *a, Int_t l, Int_t, Int_t n, Int_t &ifail)
738 //*-*-*-*-*-*-*-*-*-*-*-*Inverts a symmetric matrix*-*-*-*-*-*-*-*-*-*-*-*-*
739 //*-* ==========================
740 //*-* inverts a symmetric matrix. matrix is first scaled to
741 //*-* have all ones on the diagonal (equivalent to change of units)
742 //*-* but no pivoting is done since matrix is positive-definite.
743 //*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
745 // taken from TMinuit package of Root (l>=n)
746 // fVERTs, fVERTq and fVERTpp changed to localVERTs, localVERTq and localVERTpp
747 // Double_t localVERTs[n], localVERTq[n], localVERTpp[n];
748 Double_t * localVERTs = new Double_t[n];
749 Double_t * localVERTq = new Double_t[n];
750 Double_t * localVERTpp = new Double_t[n];
751 // fMaxint changed to localMaxint
752 Int_t localMaxint = n;
754 /* System generated locals */
757 /* Local variables */
759 Int_t i, j, k, kp1, km1;
761 /* Parameter adjustments */
767 if (n < 1) goto L100;
768 if (n > localMaxint) goto L100;
769 //*-*- scale matrix by sqrt of diag elements
770 for (i = 1; i <= n; ++i) {
772 if (si <= 0) goto L100;
773 localVERTs[i-1] = 1 / TMath::Sqrt(si);
775 for (i = 1; i <= n; ++i) {
776 for (j = 1; j <= n; ++j) {
777 a[i + j*l] = a[i + j*l]*localVERTs[i-1]*localVERTs[j-1];
780 //*-*- . . . start main loop . . . .
781 for (i = 1; i <= n; ++i) {
783 //*-*- preparation for elimination step1
784 if (a[k + k*l] != 0) localVERTq[k-1] = 1 / a[k + k*l];
786 localVERTpp[k-1] = 1;
790 if (km1 < 0) goto L100;
791 else if (km1 == 0) goto L50;
794 for (j = 1; j <= km1; ++j) {
795 localVERTpp[j-1] = a[j + k*l];
796 localVERTq[j-1] = a[j + k*l]*localVERTq[k-1];
800 if (k - n < 0) goto L51;
801 else if (k - n == 0) goto L60;
804 for (j = kp1; j <= n; ++j) {
805 localVERTpp[j-1] = a[k + j*l];
806 localVERTq[j-1] = -a[k + j*l]*localVERTq[k-1];
809 //*-*- elimination proper
811 for (j = 1; j <= n; ++j) {
812 for (k = j; k <= n; ++k) { a[j + k*l] += localVERTpp[j-1]*localVERTq[k-1]; }
815 //*-*- elements of left diagonal and unscaling
816 for (j = 1; j <= n; ++j) {
817 for (k = 1; k <= j; ++k) {
818 a[k + j*l] = a[k + j*l]*localVERTs[k-1]*localVERTs[j-1];
819 a[j + k*l] = a[k + j*l];
826 //*-*- failure return