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"
43 // Functions to be minimized with Minuit
44 void TrackChi2(Int_t &NParam, Double_t *Gradient, Double_t &Chi2, Double_t *Param, Int_t Flag);
45 void TrackChi2MCS(Int_t &NParam, Double_t *Gradient, Double_t &Chi2, Double_t *Param, Int_t Flag);
47 void mnvertLocal(Double_t* a, Int_t l, Int_t m, Int_t n, Int_t& ifail);
49 Double_t MultipleScatteringAngle2(AliMUONTrackHit *TrackHit);
51 ClassImp(AliMUONTrack) // Class implementation in ROOT context
53 TVirtualFitter* AliMUONTrack::fgFitter = NULL;
55 //__________________________________________________________________________
56 AliMUONTrack::AliMUONTrack(AliMUONSegment* BegSegment, AliMUONSegment* EndSegment, AliMUONEventReconstructor* EventReconstructor)
58 // Constructor from two Segment's
59 fEventReconstructor = EventReconstructor; // link back to EventReconstructor
60 // memory allocation for the TObjArray of pointers to reconstructed TrackHit's
61 fTrackHitsPtr = new TObjArray(10);
63 AddSegment(BegSegment); // add hits from BegSegment
64 AddSegment(EndSegment); // add hits from EndSegment
65 fTrackHitsPtr->Sort(); // sort TrackHits according to increasing Z
66 SetTrackParamAtVertex(); // set track parameters at vertex
67 // set fit conditions...
75 //__________________________________________________________________________
76 AliMUONTrack::AliMUONTrack(AliMUONSegment* Segment, AliMUONHitForRec* HitForRec, AliMUONEventReconstructor* EventReconstructor)
78 // Constructor from one Segment and one HitForRec
79 fEventReconstructor = EventReconstructor; // link back to EventReconstructor
80 // memory allocation for the TObjArray of pointers to reconstructed TrackHit's
81 fTrackHitsPtr = new TObjArray(10);
83 AddSegment(Segment); // add hits from Segment
84 AddHitForRec(HitForRec); // add HitForRec
85 fTrackHitsPtr->Sort(); // sort TrackHits according to increasing Z
86 SetTrackParamAtVertex(); // set track parameters at vertex
87 // set fit conditions...
95 //__________________________________________________________________________
96 AliMUONTrack::~AliMUONTrack()
100 delete fTrackHitsPtr; // delete the TObjArray of pointers to TrackHit's
101 fTrackHitsPtr = NULL;
105 //__________________________________________________________________________
106 AliMUONTrack::AliMUONTrack (const AliMUONTrack& MUONTrack):TObject(MUONTrack)
108 // Dummy copy constructor
111 //__________________________________________________________________________
112 AliMUONTrack & AliMUONTrack::operator=(const AliMUONTrack& /*MUONTrack*/)
114 // Dummy assignment operator
118 //__________________________________________________________________________
119 void AliMUONTrack::Remove()
121 // Remove current track from array of tracks,
122 // and corresponding track hits from array of track hits.
123 // Compress the TClonesArray it belongs to.
124 AliMUONTrackHit *nextTrackHit;
125 AliMUONEventReconstructor *eventRec = this->fEventReconstructor;
126 TClonesArray *trackHitsPtr = eventRec->GetRecTrackHitsPtr();
127 // Loop over all track hits of track
128 AliMUONTrackHit *trackHit = (AliMUONTrackHit*) fTrackHitsPtr->First();
130 nextTrackHit = (AliMUONTrackHit*) fTrackHitsPtr->After(trackHit);
131 // Remove TrackHit from event TClonesArray.
132 // Destructor is called,
133 // hence links between HitForRec's and TrackHit's are updated
134 trackHitsPtr->Remove(trackHit);
135 trackHit = nextTrackHit;
137 // Remove the track from event TClonesArray
138 // Destructor is called,
139 // hence space for TObjArray of pointers to TrackHit's is freed
140 eventRec->GetRecTracksPtr()->Remove(this);
141 // Number of tracks decreased by 1
142 eventRec->SetNRecTracks(eventRec->GetNRecTracks() - 1);
143 // Compress event TClonesArray of Track's:
144 // this is essential to retrieve the TClonesArray afterwards
145 eventRec->GetRecTracksPtr()->Compress();
146 // Compress event TClonesArray of TrackHit's:
147 // this is probably also essential to retrieve the TClonesArray afterwards
148 trackHitsPtr->Compress();
151 //__________________________________________________________________________
152 void AliMUONTrack::SetFitMCS(Int_t FitMCS)
154 // Set multiple Coulomb scattering option for track fit "fFitMCS"
155 // from "FitMCS" argument: 0 without, 1 with
156 if ((FitMCS == 0) || (FitMCS == 1)) fFitMCS = FitMCS;
157 // better implementation with enum(with, without) ????
159 cout << "ERROR in AliMUONTrack::SetFitMCS(FitMCS)" << endl;
160 cout << "FitMCS = " << FitMCS << " is neither 0 nor 1" << endl;
166 //__________________________________________________________________________
167 void AliMUONTrack::SetFitNParam(Int_t FitNParam)
169 // Set number of parameters for track fit "fFitNParam" from "FitNParam":
170 // 3 for momentum, 5 for momentum and position
171 if ((FitNParam == 3) || (FitNParam == 5)) fFitNParam = FitNParam;
173 cout << "ERROR in AliMUONTrack::SetFitNParam(FitNParam)" << endl;
174 cout << "FitNParam = " << FitNParam << " is neither 3 nor 5" << endl;
180 //__________________________________________________________________________
181 void AliMUONTrack::SetFitStart(Int_t FitStart)
183 // Set multiple Coulomb scattering option for track fit "fFitStart"
184 // from "FitStart" argument: 0 without, 1 with
185 if ((FitStart == 0) || (FitStart == 1)) fFitStart = FitStart;
186 // better implementation with enum(vertex, firstHit) ????
188 cout << "ERROR in AliMUONTrack::SetFitStart(FitStart)" << endl;
189 cout << "FitStart = " << FitStart << " is neither 0 nor 1" << endl;
195 //__________________________________________________________________________
196 AliMUONTrackParam* AliMUONTrack::GetTrackParamAtFirstHit(void) const {
197 // Get pointer to TrackParamAtFirstHit
198 return ((AliMUONTrackHit*) (fTrackHitsPtr->First()))->GetTrackParam();}
200 //__________________________________________________________________________
201 void AliMUONTrack::RecursiveDump(void) const
203 // Recursive dump of AliMUONTrack, i.e. with dump of TrackHit's and HitForRec's
204 AliMUONTrackHit *trackHit;
205 AliMUONHitForRec *hitForRec;
206 cout << "Recursive dump of Track: " << this << endl;
209 for (Int_t trackHitIndex = 0; trackHitIndex < fNTrackHits; trackHitIndex++) {
210 trackHit = (AliMUONTrackHit*) ((*fTrackHitsPtr)[trackHitIndex]);
212 cout << "TrackHit: " << trackHit << " (index: " << trackHitIndex << ")" << endl;
214 hitForRec = trackHit->GetHitForRecPtr();
216 cout << "HitForRec: " << hitForRec << endl;
222 //__________________________________________________________________________
223 Int_t AliMUONTrack::HitsInCommon(AliMUONTrack* Track)
225 // Returns the number of hits in common
226 // between the current track ("this")
227 // and the track pointed to by "Track".
228 Int_t hitsInCommon = 0;
229 AliMUONTrackHit *trackHit1, *trackHit2;
230 // Loop over hits of first track
231 trackHit1 = (AliMUONTrackHit*) this->GetTrackHitsPtr()->First();
233 // Loop over hits of second track
234 trackHit2 = (AliMUONTrackHit*) Track->GetTrackHitsPtr()->First();
236 // Increment "hitsInCommon" if both TrackHits point to the same HitForRec
237 if ( (trackHit1->GetHitForRecPtr()) ==
238 (trackHit2->GetHitForRecPtr()) ) hitsInCommon++;
239 trackHit2 = (AliMUONTrackHit*) Track->GetTrackHitsPtr()->After(trackHit2);
241 trackHit1 = (AliMUONTrackHit*) this->GetTrackHitsPtr()->After(trackHit1);
246 //__________________________________________________________________________
247 void AliMUONTrack::Fit()
249 // Fit the current track ("this"),
250 // with or without multiple Coulomb scattering according to "fFitMCS",
251 // with the number of parameters given by "fFitNParam"
252 // (3 if one keeps X and Y fixed in "TrackParam", 5 if one lets them vary),
253 // starting, according to "fFitStart",
254 // with track parameters at vertex or at the first TrackHit.
255 // "fFitMCS", "fFitNParam" and "fFitStart" have to be set before
256 // by calling the corresponding Set methods.
257 Double_t arg[1], benC, errorParam, invBenP, lower, nonBenC, upper, x, y;
259 AliMUONTrackParam *trackParam;
260 // Check if Minuit is initialized...
261 fgFitter = TVirtualFitter::Fitter(this); // add 3 or 5 for the maximum number of parameters ???
262 fgFitter->Clear(); // necessary ???? probably yes
263 // how to reset the printout number at every fit ????
264 // is there any risk to leave it like that ????
265 // how to go faster ???? choice of Minuit parameters like EDM ????
266 // choice of function to be minimized according to fFitMCS
267 if (fFitMCS == 0) fgFitter->SetFCN(TrackChi2);
268 else fgFitter->SetFCN(TrackChi2MCS);
270 fgFitter->ExecuteCommand("SET PRINT", arg, 1); // More printing !!!!
271 // Parameters according to "fFitStart"
272 // (should be a function to be used at every place where needed ????)
273 if (fFitStart == 0) trackParam = &fTrackParamAtVertex;
274 else trackParam = this->GetTrackParamAtFirstHit();
275 // set first 3 Minuit parameters
276 // could be tried with no limits for the search (min=max=0) ????
277 fgFitter->SetParameter(0, "InvBenP",
278 trackParam->GetInverseBendingMomentum(),
280 fgFitter->SetParameter(1, "BenS",
281 trackParam->GetBendingSlope(),
283 fgFitter->SetParameter(2, "NonBenS",
284 trackParam->GetNonBendingSlope(),
286 if (fFitNParam == 5) {
287 // set last 2 Minuit parameters
288 // mandatory limits in Bending to avoid NaN values of parameters
289 fgFitter->SetParameter(3, "X",
290 trackParam->GetNonBendingCoor(),
291 0.03, -500.0, 500.0);
292 // mandatory limits in non Bending to avoid NaN values of parameters
293 fgFitter->SetParameter(4, "Y",
294 trackParam->GetBendingCoor(),
295 0.10, -500.0, 500.0);
297 // search without gradient calculation in the function
298 fgFitter->ExecuteCommand("SET NOGRADIENT", arg, 0);
300 fgFitter->ExecuteCommand("MINIMIZE", arg, 0);
302 fgFitter->ExecuteCommand("EXIT", arg, 0); // necessary ????
303 // get results into "invBenP", "benC", "nonBenC" ("x", "y")
304 fgFitter->GetParameter(0, parName, invBenP, errorParam, lower, upper);
305 fgFitter->GetParameter(1, parName, benC, errorParam, lower, upper);
306 fgFitter->GetParameter(2, parName, nonBenC, errorParam, lower, upper);
307 if (fFitNParam == 5) {
308 fgFitter->GetParameter(3, parName, x, errorParam, lower, upper);
309 fgFitter->GetParameter(4, parName, y, errorParam, lower, upper);
311 // result of the fit into track parameters
312 trackParam->SetInverseBendingMomentum(invBenP);
313 trackParam->SetBendingSlope(benC);
314 trackParam->SetNonBendingSlope(nonBenC);
315 if (fFitNParam == 5) {
316 trackParam->SetNonBendingCoor(x);
317 trackParam->SetBendingCoor(y);
319 // global result of the fit
320 Double_t fedm, errdef;
322 fgFitter->GetStats(fFitFMin, fedm, errdef, npari, nparx);
325 //__________________________________________________________________________
326 void AliMUONTrack::AddSegment(AliMUONSegment* Segment)
328 // Add Segment to the track
329 AddHitForRec(Segment->GetHitForRec1()); // 1st hit
330 AddHitForRec(Segment->GetHitForRec2()); // 2nd hit
333 //__________________________________________________________________________
334 void AliMUONTrack::AddHitForRec(AliMUONHitForRec* HitForRec)
336 // Add HitForRec to the track:
337 // actual TrackHit into TClonesArray of TrackHit's for the event;
338 // pointer to actual TrackHit in TObjArray of pointers to TrackHit's for the track
339 TClonesArray *recTrackHitsPtr = this->fEventReconstructor->GetRecTrackHitsPtr();
340 Int_t eventTrackHits = this->fEventReconstructor->GetNRecTrackHits();
342 AliMUONTrackHit* trackHit =
343 new ((*recTrackHitsPtr)[eventTrackHits]) AliMUONTrackHit(HitForRec);
344 this->fEventReconstructor->SetNRecTrackHits(eventTrackHits + 1);
346 fTrackHitsPtr->Add(trackHit);
350 //__________________________________________________________________________
351 void AliMUONTrack::SetTrackParamAtHit(Int_t indexHit, AliMUONTrackParam *TrackParam) const
353 // Set track parameters at TrackHit with index "indexHit"
354 // from the track parameters pointed to by "TrackParam".
355 //PH AliMUONTrackHit* trackHit = (AliMUONTrackHit*) ((*fTrackHitsPtr)[indexHit]);
356 AliMUONTrackHit* trackHit = (AliMUONTrackHit*) (fTrackHitsPtr->At(indexHit));
357 trackHit->SetTrackParam(TrackParam);
360 //__________________________________________________________________________
361 void AliMUONTrack::SetTrackParamAtVertex()
363 // Set track parameters at vertex.
364 // TrackHit's are assumed to be only in stations(1..) 4 and 5,
365 // and sorted according to increasing Z..
366 // Parameters are calculated from information in HitForRec's
367 // of first and last TrackHit's.
368 AliMUONTrackParam *trackParam =
369 &fTrackParamAtVertex; // pointer to track parameters
370 // Pointer to HitForRec of first TrackHit
371 AliMUONHitForRec *firstHit =
372 ((AliMUONTrackHit*) (fTrackHitsPtr->First()))->GetHitForRecPtr();
373 // Pointer to HitForRec of last TrackHit
374 AliMUONHitForRec *lastHit =
375 ((AliMUONTrackHit*) (fTrackHitsPtr->Last()))->GetHitForRecPtr();
376 // Z difference between first and last hits
377 Double_t deltaZ = firstHit->GetZ() - lastHit->GetZ();
378 // bending slope in stations(1..) 4 and 5
379 Double_t bendingSlope =
380 (firstHit->GetBendingCoor() - lastHit->GetBendingCoor()) / deltaZ;
381 trackParam->SetBendingSlope(bendingSlope);
383 Double_t impactParam =
384 firstHit->GetBendingCoor() - bendingSlope * firstHit->GetZ(); // same if from firstHit and lastHit ????
385 // signed bending momentum
386 Double_t signedBendingMomentum =
387 fEventReconstructor->GetBendingMomentumFromImpactParam(impactParam);
388 trackParam->SetInverseBendingMomentum(1.0 / signedBendingMomentum);
389 // bending slope at vertex
391 SetBendingSlope(bendingSlope +
392 impactParam / fEventReconstructor->GetSimpleBPosition());
394 Double_t nonBendingSlope =
395 (firstHit->GetNonBendingCoor() - lastHit->GetNonBendingCoor()) / deltaZ;
396 trackParam->SetNonBendingSlope(nonBendingSlope);
397 // vertex coordinates at (0,0,0)
398 trackParam->SetZ(0.0);
399 trackParam->SetBendingCoor(0.0);
400 trackParam->SetNonBendingCoor(0.0);
403 //__________________________________________________________________________
404 void TrackChi2(Int_t &NParam, Double_t * /*Gradient*/, Double_t &Chi2, Double_t *Param, Int_t /*Flag*/)
406 // Return the "Chi2" to be minimized with Minuit for track fitting,
407 // with "NParam" parameters
408 // and their current values in array pointed to by "Param".
409 // Assumes that the track hits are sorted according to increasing Z.
410 // Track parameters at each TrackHit are updated accordingly.
411 // Multiple Coulomb scattering is not taken into account
412 AliMUONTrack *trackBeingFitted;
413 AliMUONTrackHit* hit;
414 AliMUONTrackParam param1;
417 Chi2 = 0.0; // initialize Chi2
418 // copy of track parameters to be fitted
419 trackBeingFitted = (AliMUONTrack*) AliMUONTrack::Fitter()->GetObjectFit();
420 if (trackBeingFitted->GetFitStart() == 0)
421 param1 = *(trackBeingFitted->GetTrackParamAtVertex());
422 else param1 = *(trackBeingFitted->GetTrackParamAtFirstHit());
423 // Minuit parameters to be fitted into this copy
424 param1.SetInverseBendingMomentum(Param[0]);
425 param1.SetBendingSlope(Param[1]);
426 param1.SetNonBendingSlope(Param[2]);
428 param1.SetNonBendingCoor(Param[3]);
429 param1.SetBendingCoor(Param[4]);
431 // Follow track through all planes of track hits
432 for (hitNumber = 0; hitNumber < trackBeingFitted->GetNTrackHits(); hitNumber++) {
433 hit = (AliMUONTrackHit*) (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber];
434 zHit = hit->GetHitForRecPtr()->GetZ();
435 // do something special if 2 hits with same Z ????
436 // security against infinite loop ????
437 (¶m1)->ExtrapToZ(zHit); // extrapolation
438 hit->SetTrackParam(¶m1);
440 // done hit per hit, with hit resolution,
441 // and not with point and angle like in "reco_muon.F" !!!!
442 // Needs to add multiple scattering contribution ????
444 hit->GetHitForRecPtr()->GetNonBendingCoor() - (¶m1)->GetNonBendingCoor();
446 hit->GetHitForRecPtr()->GetBendingCoor() - (¶m1)->GetBendingCoor();
449 dX * dX / hit->GetHitForRecPtr()->GetNonBendingReso2() +
450 dY * dY / hit->GetHitForRecPtr()->GetBendingReso2();
454 //__________________________________________________________________________
455 void TrackChi2MCS(Int_t &NParam, Double_t * /*Gradient*/, Double_t &Chi2, Double_t *Param, Int_t /*Flag*/)
457 // Return the "Chi2" to be minimized with Minuit for track fitting,
458 // with "NParam" parameters
459 // and their current values in array pointed to by "Param".
460 // Assumes that the track hits are sorted according to increasing Z.
461 // Track parameters at each TrackHit are updated accordingly.
462 // Multiple Coulomb scattering is taken into account with covariance matrix.
463 AliMUONTrack *trackBeingFitted;
464 AliMUONTrackParam param1;
465 Chi2 = 0.0; // initialize Chi2
466 // copy of track parameters to be fitted
467 trackBeingFitted = (AliMUONTrack*) AliMUONTrack::Fitter()->GetObjectFit();
468 if (trackBeingFitted->GetFitStart() == 0)
469 param1 = *(trackBeingFitted->GetTrackParamAtVertex());
470 else param1 = *(trackBeingFitted->GetTrackParamAtFirstHit());
471 // Minuit parameters to be fitted into this copy
472 param1.SetInverseBendingMomentum(Param[0]);
473 param1.SetBendingSlope(Param[1]);
474 param1.SetNonBendingSlope(Param[2]);
476 param1.SetNonBendingCoor(Param[3]);
477 param1.SetBendingCoor(Param[4]);
480 AliMUONTrackHit *hit;
481 Int_t chCurrent, chPrev = 0, hitNumber, hitNumber1, hitNumber2, hitNumber3;
482 Double_t z, z1, z2, z3;
483 AliMUONTrackHit *hit1, *hit2, *hit3;
484 Double_t hbc1, hbc2, pbc1, pbc2;
485 Double_t hnbc1, hnbc2, pnbc1, pnbc2;
486 Int_t numberOfHit = trackBeingFitted->GetNTrackHits();
487 TMatrixD *covBending = new TMatrixD(numberOfHit, numberOfHit);
488 TMatrixD *covNonBending = new TMatrixD(numberOfHit, numberOfHit);
489 Double_t *msa2 = new Double_t[numberOfHit];
491 // Predicted coordinates and multiple scattering angles are first calculated
492 for (hitNumber = 0; hitNumber < numberOfHit; hitNumber++) {
493 hit = (AliMUONTrackHit*) (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber];
494 z = hit->GetHitForRecPtr()->GetZ();
495 // do something special if 2 hits with same Z ????
496 // security against infinite loop ????
497 (¶m1)->ExtrapToZ(z); // extrapolation
498 hit->SetTrackParam(¶m1);
499 // square of multiple scattering angle at current hit, with one chamber
500 msa2[hitNumber] = MultipleScatteringAngle2(hit);
501 // correction for eventual missing hits or multiple hits in a chamber,
502 // according to the number of chambers
503 // between the current hit and the previous one
504 chCurrent = hit->GetHitForRecPtr()->GetChamberNumber();
505 if (hitNumber > 0) msa2[hitNumber] = msa2[hitNumber] * (chCurrent - chPrev);
509 // Calculates the covariance matrix
510 for (hitNumber1 = 0; hitNumber1 < numberOfHit; hitNumber1++) {
511 hit1 = (AliMUONTrackHit*) (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber1];
512 z1 = hit1->GetHitForRecPtr()->GetZ();
513 for (hitNumber2 = hitNumber1; hitNumber2 < numberOfHit; hitNumber2++) {
514 hit2 = (AliMUONTrackHit*) (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber2];
515 z2 = hit2->GetHitForRecPtr()->GetZ();
516 // initialization to 0 (diagonal plus upper triangular part)
517 (*covBending)(hitNumber2, hitNumber1) = 0.0;
518 // contribution from multiple scattering in bending plane:
519 // loop over upstream hits
520 for (hitNumber3 = 0; hitNumber3 < hitNumber1; hitNumber3++) {
521 hit3 = (AliMUONTrackHit*)
522 (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber3];
523 z3 = hit3->GetHitForRecPtr()->GetZ();
524 (*covBending)(hitNumber2, hitNumber1) =
525 (*covBending)(hitNumber2, hitNumber1) +
526 ((z1 - z3) * (z2 - z3) * msa2[hitNumber3]);
528 // equal contribution from multiple scattering in non bending plane
529 (*covNonBending)(hitNumber2, hitNumber1) =
530 (*covBending)(hitNumber2, hitNumber1);
531 if (hitNumber1 == hitNumber2) {
532 // Diagonal elements: add contribution from position measurements
534 (*covBending)(hitNumber2, hitNumber1) =
535 (*covBending)(hitNumber2, hitNumber1) +
536 hit1->GetHitForRecPtr()->GetBendingReso2();
537 // and in non bending plane
538 (*covNonBending)(hitNumber2, hitNumber1) =
539 (*covNonBending)(hitNumber2, hitNumber1) +
540 hit1->GetHitForRecPtr()->GetNonBendingReso2();
543 // Non diagonal elements: symmetrization
545 (*covBending)(hitNumber1, hitNumber2) =
546 (*covBending)(hitNumber2, hitNumber1);
547 // and non bending plane
548 (*covNonBending)(hitNumber1, hitNumber2) =
549 (*covNonBending)(hitNumber2, hitNumber1);
551 } // for (hitNumber2 = hitNumber1;...
552 } // for (hitNumber1 = 0;...
554 // Inversion of covariance matrices
555 // with "mnvertLocal", local "mnvert" function of Minuit.
556 // One cannot use directly "mnvert" since "TVirtualFitter" does not know it.
557 // One will have to replace this local function by the right inversion function
558 // from a specialized Root package for symmetric positive definite matrices,
559 // when available!!!!
561 mnvertLocal(&((*covBending)(0,0)), numberOfHit, numberOfHit, numberOfHit,
563 Int_t ifailNonBending;
564 mnvertLocal(&((*covNonBending)(0,0)), numberOfHit, numberOfHit, numberOfHit,
567 // It would be worth trying to calculate the inverse of the covariance matrix
568 // only once per fit, since it cannot change much in principle,
569 // and it would save a lot of computing time !!!!
572 if ((ifailBending == 0) && (ifailNonBending == 0)) {
573 // with Multiple Scattering if inversion correct
574 for (hitNumber1 = 0; hitNumber1 < numberOfHit ; hitNumber1++) {
575 hit1 = (AliMUONTrackHit*) (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber1];
576 hbc1 = hit1->GetHitForRecPtr()->GetBendingCoor();
577 pbc1 = hit1->GetTrackParam()->GetBendingCoor();
578 hnbc1 = hit1->GetHitForRecPtr()->GetNonBendingCoor();
579 pnbc1 = hit1->GetTrackParam()->GetNonBendingCoor();
580 for (hitNumber2 = 0; hitNumber2 < numberOfHit; hitNumber2++) {
581 hit2 = (AliMUONTrackHit*)
582 (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber2];
583 hbc2 = hit2->GetHitForRecPtr()->GetBendingCoor();
584 pbc2 = hit2->GetTrackParam()->GetBendingCoor();
585 hnbc2 = hit2->GetHitForRecPtr()->GetNonBendingCoor();
586 pnbc2 = hit2->GetTrackParam()->GetNonBendingCoor();
588 ((*covBending)(hitNumber2, hitNumber1) *
589 (hbc1 - pbc1) * (hbc2 - pbc2)) +
590 ((*covNonBending)(hitNumber2, hitNumber1) *
591 (hnbc1 - pnbc1) * (hnbc2 - pnbc2));
595 // without Multiple Scattering if inversion impossible
596 for (hitNumber1 = 0; hitNumber1 < numberOfHit ; hitNumber1++) {
597 hit1 = (AliMUONTrackHit*) (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber1];
598 hbc1 = hit1->GetHitForRecPtr()->GetBendingCoor();
599 pbc1 = hit1->GetTrackParam()->GetBendingCoor();
600 hnbc1 = hit1->GetHitForRecPtr()->GetNonBendingCoor();
601 pnbc1 = hit1->GetTrackParam()->GetNonBendingCoor();
603 ((hbc1 - pbc1) * (hbc1 - pbc1) /
604 hit1->GetHitForRecPtr()->GetBendingReso2()) +
605 ((hnbc1 - pnbc1) * (hnbc1 - pnbc1) /
606 hit1->GetHitForRecPtr()->GetNonBendingReso2());
611 delete covNonBending;
615 Double_t MultipleScatteringAngle2(AliMUONTrackHit *TrackHit)
617 // Returns square of multiple Coulomb scattering angle
618 // at TrackHit pointed to by "TrackHit"
619 Double_t slopeBending, slopeNonBending, radiationLength, inverseBendingMomentum2, inverseTotalMomentum2;
620 Double_t varMultipleScatteringAngle;
621 AliMUONTrack *trackBeingFitted = (AliMUONTrack*) AliMUONTrack::Fitter()->GetObjectFit();
622 AliMUONTrackParam *param = TrackHit->GetTrackParam();
623 // Better implementation in AliMUONTrack class ????
624 slopeBending = param->GetBendingSlope();
625 slopeNonBending = param->GetNonBendingSlope();
626 // thickness in radiation length for the current track,
627 // taking local angle into account
629 trackBeingFitted->GetEventReconstructor()->GetChamberThicknessInX0() *
631 slopeBending * slopeBending + slopeNonBending * slopeNonBending);
632 inverseBendingMomentum2 =
633 param->GetInverseBendingMomentum() * param->GetInverseBendingMomentum();
634 inverseTotalMomentum2 =
635 inverseBendingMomentum2 * (1.0 + slopeBending * slopeBending) /
636 (1.0 + slopeBending *slopeBending + slopeNonBending * slopeNonBending);
637 varMultipleScatteringAngle = 0.0136 * (1.0 + 0.038 * TMath::Log(radiationLength));
638 // The velocity is assumed to be 1 !!!!
639 varMultipleScatteringAngle = inverseTotalMomentum2 * radiationLength *
640 varMultipleScatteringAngle * varMultipleScatteringAngle;
641 return varMultipleScatteringAngle;
644 //______________________________________________________________________________
645 void mnvertLocal(Double_t *a, Int_t l, Int_t, Int_t n, Int_t &ifail)
647 //*-*-*-*-*-*-*-*-*-*-*-*Inverts a symmetric matrix*-*-*-*-*-*-*-*-*-*-*-*-*
648 //*-* ==========================
649 //*-* inverts a symmetric matrix. matrix is first scaled to
650 //*-* have all ones on the diagonal (equivalent to change of units)
651 //*-* but no pivoting is done since matrix is positive-definite.
652 //*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
654 // taken from TMinuit package of Root (l>=n)
655 // fVERTs, fVERTq and fVERTpp changed to localVERTs, localVERTq and localVERTpp
656 // Double_t localVERTs[n], localVERTq[n], localVERTpp[n];
657 Double_t * localVERTs = new Double_t[n];
658 Double_t * localVERTq = new Double_t[n];
659 Double_t * localVERTpp = new Double_t[n];
660 // fMaxint changed to localMaxint
661 Int_t localMaxint = n;
663 /* System generated locals */
666 /* Local variables */
668 Int_t i, j, k, kp1, km1;
670 /* Parameter adjustments */
676 if (n < 1) goto L100;
677 if (n > localMaxint) goto L100;
678 //*-*- scale matrix by sqrt of diag elements
679 for (i = 1; i <= n; ++i) {
681 if (si <= 0) goto L100;
682 localVERTs[i-1] = 1 / TMath::Sqrt(si);
684 for (i = 1; i <= n; ++i) {
685 for (j = 1; j <= n; ++j) {
686 a[i + j*l] = a[i + j*l]*localVERTs[i-1]*localVERTs[j-1];
689 //*-*- . . . start main loop . . . .
690 for (i = 1; i <= n; ++i) {
692 //*-*- preparation for elimination step1
693 if (a[k + k*l] != 0) localVERTq[k-1] = 1 / a[k + k*l];
695 localVERTpp[k-1] = 1;
699 if (km1 < 0) goto L100;
700 else if (km1 == 0) goto L50;
703 for (j = 1; j <= km1; ++j) {
704 localVERTpp[j-1] = a[j + k*l];
705 localVERTq[j-1] = a[j + k*l]*localVERTq[k-1];
709 if (k - n < 0) goto L51;
710 else if (k - n == 0) goto L60;
713 for (j = kp1; j <= n; ++j) {
714 localVERTpp[j-1] = a[k + j*l];
715 localVERTq[j-1] = -a[k + j*l]*localVERTq[k-1];
718 //*-*- elimination proper
720 for (j = 1; j <= n; ++j) {
721 for (k = j; k <= n; ++k) { a[j + k*l] += localVERTpp[j-1]*localVERTq[k-1]; }
724 //*-*- elements of left diagonal and unscaling
725 for (j = 1; j <= n; ++j) {
726 for (k = 1; k <= j; ++k) {
727 a[k + j*l] = a[k + j*l]*localVERTs[k-1]*localVERTs[j-1];
728 a[j + k*l] = a[k + j*l];
735 //*-*- failure return