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a9e2aefa | 1 | /************************************************************************** |
2 | * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. * | |
3 | * * | |
4 | * Author: The ALICE Off-line Project. * | |
5 | * Contributors are mentioned in the code where appropriate. * | |
6 | * * | |
7 | * Permission to use, copy, modify and distribute this software and its * | |
8 | * documentation strictly for non-commercial purposes is hereby granted * | |
9 | * without fee, provided that the above copyright notice appears in all * | |
10 | * copies and that both the copyright notice and this permission notice * | |
11 | * appear in the supporting documentation. The authors make no claims * | |
12 | * about the suitability of this software for any purpose. It is * | |
13 | * provided "as is" without express or implied warranty. * | |
14 | **************************************************************************/ | |
15 | ||
16 | /* | |
17 | $Log$ | |
eb9c9dab | 18 | Revision 1.6 2000/07/20 12:45:27 gosset |
19 | New "EventReconstructor..." structure, | |
20 | hopefully more adapted to tree/streamer. | |
21 | "AliMUONEventReconstructor::RemoveDoubleTracks" | |
22 | to keep only one track among similar ones. | |
23 | ||
8429a5e4 | 24 | Revision 1.5 2000/07/18 16:04:06 gosset |
25 | AliMUONEventReconstructor package: | |
26 | * a few minor modifications and more comments | |
27 | * a few corrections | |
28 | * right sign for Z of raw clusters | |
29 | * right loop over chambers inside station | |
30 | * symmetrized covariance matrix for measurements (TrackChi2MCS) | |
31 | * right sign of charge in extrapolation (ExtrapToZ) | |
32 | * right zEndAbsorber for Branson correction below 3 degrees | |
33 | * use of TVirtualFitter instead of TMinuit for AliMUONTrack::Fit | |
34 | * no parameter for AliMUONTrack::Fit() but more fit parameters in Track object | |
35 | ||
956019b6 | 36 | Revision 1.4 2000/06/30 10:15:48 gosset |
37 | Changes to EventReconstructor...: | |
38 | precision fit with multiple Coulomb scattering; | |
39 | extrapolation to vertex with Branson correction in absorber (JPC) | |
40 | ||
04b5ea16 | 41 | Revision 1.3 2000/06/25 13:23:28 hristov |
42 | stdlib.h needed for non-Linux compilation | |
43 | ||
f6e92cf4 | 44 | Revision 1.2 2000/06/15 07:58:48 morsch |
45 | Code from MUON-dev joined | |
46 | ||
a9e2aefa | 47 | Revision 1.1.2.3 2000/06/12 10:11:34 morsch |
48 | Dummy copy constructor and assignment operator added | |
49 | ||
50 | Revision 1.1.2.2 2000/06/09 12:58:05 gosset | |
51 | Removed comment beginnings in Log sections of .cxx files | |
52 | Suppressed most violations of coding rules | |
53 | ||
54 | Revision 1.1.2.1 2000/06/07 14:44:53 gosset | |
55 | Addition of files for track reconstruction in C++ | |
56 | */ | |
57 | ||
58 | //__________________________________________________________________________ | |
59 | // | |
60 | // Reconstructed track in ALICE dimuon spectrometer | |
61 | //__________________________________________________________________________ | |
62 | ||
63 | #include "AliMUONTrack.h" | |
64 | ||
65 | #include <iostream.h> | |
66 | ||
67 | #include <TClonesArray.h> | |
04b5ea16 | 68 | #include <TMath.h> |
69 | #include <TMatrix.h> | |
8429a5e4 | 70 | #include <TObjArray.h> |
956019b6 | 71 | #include <TVirtualFitter.h> |
a9e2aefa | 72 | |
73 | #include "AliMUONEventReconstructor.h" | |
74 | #include "AliMUONHitForRec.h" | |
75 | #include "AliMUONSegment.h" | |
76 | #include "AliMUONTrackHit.h" | |
77 | ||
f6e92cf4 | 78 | #include <stdlib.h> |
79 | ||
04b5ea16 | 80 | // Functions to be minimized with Minuit |
a9e2aefa | 81 | void TrackChi2(Int_t &NParam, Double_t *Gradient, Double_t &Chi2, Double_t *Param, Int_t Flag); |
04b5ea16 | 82 | void TrackChi2MCS(Int_t &NParam, Double_t *Gradient, Double_t &Chi2, Double_t *Param, Int_t Flag); |
83 | ||
84 | Double_t MultipleScatteringAngle2(AliMUONTrackHit *TrackHit); | |
a9e2aefa | 85 | |
86 | ClassImp(AliMUONTrack) // Class implementation in ROOT context | |
87 | ||
956019b6 | 88 | TVirtualFitter* AliMUONTrack::fgFitter = NULL; |
89 | ||
a9e2aefa | 90 | //__________________________________________________________________________ |
91 | AliMUONTrack::AliMUONTrack(AliMUONSegment* BegSegment, AliMUONSegment* EndSegment, AliMUONEventReconstructor* EventReconstructor) | |
92 | { | |
93 | // Constructor from two Segment's | |
94 | fEventReconstructor = EventReconstructor; // link back to EventReconstructor | |
8429a5e4 | 95 | // memory allocation for the TObjArray of pointers to reconstructed TrackHit's |
96 | fTrackHitsPtr = new TObjArray(10); | |
a9e2aefa | 97 | fNTrackHits = 0; |
98 | AddSegment(BegSegment); // add hits from BegSegment | |
99 | AddSegment(EndSegment); // add hits from EndSegment | |
100 | fTrackHitsPtr->Sort(); // sort TrackHits according to increasing Z | |
101 | SetTrackParamAtVertex(); // set track parameters at vertex | |
8429a5e4 | 102 | // set fit conditions... |
04b5ea16 | 103 | fFitMCS = 0; |
956019b6 | 104 | fFitNParam = 3; |
105 | fFitStart = 1; | |
8429a5e4 | 106 | fFitFMin = -1.0; |
a9e2aefa | 107 | return; |
108 | } | |
109 | ||
110 | //__________________________________________________________________________ | |
111 | AliMUONTrack::AliMUONTrack(AliMUONSegment* Segment, AliMUONHitForRec* HitForRec, AliMUONEventReconstructor* EventReconstructor) | |
112 | { | |
113 | // Constructor from one Segment and one HitForRec | |
114 | fEventReconstructor = EventReconstructor; // link back to EventReconstructor | |
8429a5e4 | 115 | // memory allocation for the TObjArray of pointers to reconstructed TrackHit's |
116 | fTrackHitsPtr = new TObjArray(10); | |
a9e2aefa | 117 | fNTrackHits = 0; |
118 | AddSegment(Segment); // add hits from Segment | |
119 | AddHitForRec(HitForRec); // add HitForRec | |
120 | fTrackHitsPtr->Sort(); // sort TrackHits according to increasing Z | |
121 | SetTrackParamAtVertex(); // set track parameters at vertex | |
8429a5e4 | 122 | // set fit conditions... |
04b5ea16 | 123 | fFitMCS = 0; |
956019b6 | 124 | fFitNParam = 3; |
125 | fFitStart = 1; | |
8429a5e4 | 126 | fFitFMin = -1.0; |
a9e2aefa | 127 | return; |
128 | } | |
129 | ||
8429a5e4 | 130 | //__________________________________________________________________________ |
131 | AliMUONTrack::~AliMUONTrack() | |
132 | { | |
133 | // Destructor | |
134 | if (fTrackHitsPtr) { | |
135 | delete fTrackHitsPtr; // delete the TObjArray of pointers to TrackHit's | |
136 | fTrackHitsPtr = NULL; | |
137 | } | |
138 | } | |
139 | ||
956019b6 | 140 | //__________________________________________________________________________ |
a9e2aefa | 141 | AliMUONTrack::AliMUONTrack (const AliMUONTrack& MUONTrack) |
142 | { | |
143 | // Dummy copy constructor | |
144 | } | |
145 | ||
956019b6 | 146 | //__________________________________________________________________________ |
a9e2aefa | 147 | AliMUONTrack & AliMUONTrack::operator=(const AliMUONTrack& MUONTrack) |
148 | { | |
149 | // Dummy assignment operator | |
150 | return *this; | |
151 | } | |
152 | ||
8429a5e4 | 153 | //__________________________________________________________________________ |
154 | void AliMUONTrack::Remove() | |
155 | { | |
156 | // Remove current track from array of tracks, | |
157 | // and corresponding track hits from array of track hits. | |
158 | // Compress the TClonesArray it belongs to. | |
159 | AliMUONTrackHit *nextTrackHit; | |
160 | AliMUONEventReconstructor *eventRec = this->fEventReconstructor; | |
161 | TClonesArray *trackHitsPtr = eventRec->GetRecTrackHitsPtr(); | |
162 | // Loop over all track hits of track | |
163 | AliMUONTrackHit *trackHit = (AliMUONTrackHit*) fTrackHitsPtr->First(); | |
164 | while (trackHit) { | |
165 | nextTrackHit = (AliMUONTrackHit*) fTrackHitsPtr->After(trackHit); | |
166 | // Remove TrackHit from event TClonesArray. | |
167 | // Destructor is called, | |
168 | // hence links between HitForRec's and TrackHit's are updated | |
169 | trackHitsPtr->Remove(trackHit); | |
170 | trackHit = nextTrackHit; | |
171 | } | |
172 | // Remove the track from event TClonesArray | |
173 | // Destructor is called, | |
174 | // hence space for TObjArray of pointers to TrackHit's is freed | |
175 | eventRec->GetRecTracksPtr()->Remove(this); | |
176 | // Number of tracks decreased by 1 | |
177 | eventRec->SetNRecTracks(eventRec->GetNRecTracks() - 1); | |
178 | // Compress event TClonesArray of Track's: | |
179 | // this is essential to retrieve the TClonesArray afterwards | |
180 | eventRec->GetRecTracksPtr()->Compress(); | |
181 | // Compress event TClonesArray of TrackHit's: | |
182 | // this is probably also essential to retrieve the TClonesArray afterwards | |
183 | trackHitsPtr->Compress(); | |
184 | } | |
185 | ||
04b5ea16 | 186 | //__________________________________________________________________________ |
187 | void AliMUONTrack::SetFitMCS(Int_t FitMCS) | |
188 | { | |
956019b6 | 189 | // Set multiple Coulomb scattering option for track fit "fFitMCS" |
04b5ea16 | 190 | // from "FitMCS" argument: 0 without, 1 with |
956019b6 | 191 | if ((FitMCS == 0) || (FitMCS == 1)) fFitMCS = FitMCS; |
04b5ea16 | 192 | // better implementation with enum(with, without) ???? |
956019b6 | 193 | else { |
194 | cout << "ERROR in AliMUONTrack::SetFitMCS(FitMCS)" << endl; | |
195 | cout << "FitMCS = " << FitMCS << " is neither 0 nor 1" << endl; | |
196 | exit(0); | |
197 | } | |
198 | return; | |
199 | } | |
200 | ||
201 | //__________________________________________________________________________ | |
202 | void AliMUONTrack::SetFitNParam(Int_t FitNParam) | |
203 | { | |
204 | // Set number of parameters for track fit "fFitNParam" from "FitNParam": | |
205 | // 3 for momentum, 5 for momentum and position | |
206 | if ((FitNParam == 3) || (FitNParam == 5)) fFitNParam = FitNParam; | |
207 | else { | |
208 | cout << "ERROR in AliMUONTrack::SetFitNParam(FitNParam)" << endl; | |
209 | cout << "FitNParam = " << FitNParam << " is neither 3 nor 5" << endl; | |
210 | exit(0); | |
211 | } | |
212 | return; | |
213 | } | |
214 | ||
215 | //__________________________________________________________________________ | |
216 | void AliMUONTrack::SetFitStart(Int_t FitStart) | |
217 | { | |
218 | // Set multiple Coulomb scattering option for track fit "fFitStart" | |
219 | // from "FitStart" argument: 0 without, 1 with | |
220 | if ((FitStart == 0) || (FitStart == 1)) fFitStart = FitStart; | |
221 | // better implementation with enum(vertex, firstHit) ???? | |
222 | else { | |
223 | cout << "ERROR in AliMUONTrack::SetFitStart(FitStart)" << endl; | |
224 | cout << "FitStart = " << FitStart << " is neither 0 nor 1" << endl; | |
225 | exit(0); | |
226 | } | |
04b5ea16 | 227 | return; |
228 | } | |
229 | ||
956019b6 | 230 | //__________________________________________________________________________ |
a9e2aefa | 231 | AliMUONTrackParam* AliMUONTrack::GetTrackParamAtFirstHit(void) { |
232 | // Get pointer to TrackParamAtFirstHit | |
233 | return ((AliMUONTrackHit*) (fTrackHitsPtr->First()))->GetTrackParam();} | |
a9e2aefa | 234 | |
235 | //__________________________________________________________________________ | |
236 | void AliMUONTrack::RecursiveDump(void) | |
237 | { | |
238 | // Recursive dump of AliMUONTrack, i.e. with dump of TrackHit's and HitForRec's | |
239 | AliMUONTrackHit *trackHit; | |
240 | AliMUONHitForRec *hitForRec; | |
241 | cout << "Recursive dump of Track: " << this << endl; | |
242 | // Track | |
243 | this->Dump(); | |
244 | for (Int_t trackHitIndex = 0; trackHitIndex < fNTrackHits; trackHitIndex++) { | |
245 | trackHit = (AliMUONTrackHit*) ((*fTrackHitsPtr)[trackHitIndex]); | |
246 | // TrackHit | |
247 | cout << "TrackHit: " << trackHit << " (index: " << trackHitIndex << ")" << endl; | |
248 | trackHit->Dump(); | |
249 | hitForRec = trackHit->GetHitForRecPtr(); | |
250 | // HitForRec | |
251 | cout << "HitForRec: " << hitForRec << endl; | |
252 | hitForRec->Dump(); | |
253 | } | |
254 | return; | |
255 | } | |
256 | ||
8429a5e4 | 257 | //__________________________________________________________________________ |
258 | Int_t AliMUONTrack::HitsInCommon(AliMUONTrack* Track) | |
259 | { | |
260 | // Returns the number of hits in common | |
261 | // between the current track ("this") | |
262 | // and the track pointed to by "Track". | |
263 | Int_t hitsInCommon = 0; | |
264 | AliMUONTrackHit *trackHit1, *trackHit2; | |
265 | // Loop over hits of first track | |
266 | trackHit1 = (AliMUONTrackHit*) this->GetTrackHitsPtr()->First(); | |
267 | while (trackHit1) { | |
268 | // Loop over hits of second track | |
269 | trackHit2 = (AliMUONTrackHit*) Track->GetTrackHitsPtr()->First(); | |
270 | while (trackHit2) { | |
271 | // Increment "hitsInCommon" if both TrackHits point to the same HitForRec | |
272 | if ( (trackHit1->GetHitForRecPtr()) == | |
273 | (trackHit2->GetHitForRecPtr()) ) hitsInCommon++; | |
274 | trackHit2 = (AliMUONTrackHit*) Track->GetTrackHitsPtr()->After(trackHit2); | |
275 | } // trackHit2 | |
276 | trackHit1 = (AliMUONTrackHit*) this->GetTrackHitsPtr()->After(trackHit1); | |
277 | } // trackHit1 | |
278 | return hitsInCommon; | |
279 | } | |
280 | ||
a9e2aefa | 281 | //__________________________________________________________________________ |
956019b6 | 282 | void AliMUONTrack::Fit() |
a9e2aefa | 283 | { |
284 | // Fit the current track ("this"), | |
956019b6 | 285 | // with or without multiple Coulomb scattering according to "fFitMCS", |
286 | // with the number of parameters given by "fFitNParam" | |
287 | // (3 if one keeps X and Y fixed in "TrackParam", 5 if one lets them vary), | |
288 | // starting, according to "fFitStart", | |
289 | // with track parameters at vertex or at the first TrackHit. | |
290 | // "fFitMCS", "fFitNParam" and "fFitStart" have to be set before | |
291 | // by calling the corresponding Set methods. | |
a9e2aefa | 292 | Double_t arg[1], benC, errorParam, invBenP, lower, nonBenC, upper, x, y; |
956019b6 | 293 | char parName[50]; |
294 | AliMUONTrackParam *trackParam; | |
295 | // Check if Minuit is initialized... | |
296 | fgFitter = TVirtualFitter::Fitter(this); // add 3 or 5 for the maximum number of parameters ??? | |
297 | fgFitter->Clear(); // necessary ???? probably yes | |
298 | // how to reset the printout number at every fit ???? | |
299 | // is there any risk to leave it like that ???? | |
a9e2aefa | 300 | // how to go faster ???? choice of Minuit parameters like EDM ???? |
04b5ea16 | 301 | // choice of function to be minimized according to fFitMCS |
956019b6 | 302 | if (fFitMCS == 0) fgFitter->SetFCN(TrackChi2); |
303 | else fgFitter->SetFCN(TrackChi2MCS); | |
304 | arg[0] = 1; | |
305 | fgFitter->ExecuteCommand("SET PRINT", arg, 1); // More printing !!!! | |
306 | // Parameters according to "fFitStart" | |
307 | // (should be a function to be used at every place where needed ????) | |
308 | if (fFitStart == 0) trackParam = &fTrackParamAtVertex; | |
309 | else trackParam = this->GetTrackParamAtFirstHit(); | |
310 | // set first 3 Minuit parameters | |
04b5ea16 | 311 | // could be tried with no limits for the search (min=max=0) ???? |
956019b6 | 312 | fgFitter->SetParameter(0, "InvBenP", |
313 | trackParam->GetInverseBendingMomentum(), | |
314 | 0.003, -0.4, 0.4); | |
315 | fgFitter->SetParameter(1, "BenS", | |
316 | trackParam->GetBendingSlope(), | |
317 | 0.001, -0.5, 0.5); | |
318 | fgFitter->SetParameter(2, "NonBenS", | |
319 | trackParam->GetNonBendingSlope(), | |
320 | 0.001, -0.5, 0.5); | |
321 | if (fFitNParam == 5) { | |
322 | // set last 2 Minuit parameters (no limits for the search: min=max=0) | |
323 | fgFitter->SetParameter(3, "X", | |
324 | trackParam->GetNonBendingCoor(), | |
325 | 0.03, 0.0, 0.0); | |
326 | fgFitter->SetParameter(4, "Y", | |
327 | trackParam->GetBendingCoor(), | |
328 | 0.10, 0.0, 0.0); | |
a9e2aefa | 329 | } |
330 | // search without gradient calculation in the function | |
956019b6 | 331 | fgFitter->ExecuteCommand("SET NOGRADIENT", arg, 0); |
a9e2aefa | 332 | // minimization |
956019b6 | 333 | fgFitter->ExecuteCommand("MINIMIZE", arg, 0); |
a9e2aefa | 334 | // exit from Minuit |
956019b6 | 335 | fgFitter->ExecuteCommand("EXIT", arg, 0); // necessary ???? |
336 | // get results into "invBenP", "benC", "nonBenC" ("x", "y") | |
337 | fgFitter->GetParameter(0, parName, invBenP, errorParam, lower, upper); | |
338 | fgFitter->GetParameter(1, parName, benC, errorParam, lower, upper); | |
339 | fgFitter->GetParameter(2, parName, nonBenC, errorParam, lower, upper); | |
340 | if (fFitNParam == 5) { | |
341 | fgFitter->GetParameter(3, parName, x, errorParam, lower, upper); | |
342 | fgFitter->GetParameter(4, parName, y, errorParam, lower, upper); | |
a9e2aefa | 343 | } |
344 | // result of the fit into track parameters | |
956019b6 | 345 | trackParam->SetInverseBendingMomentum(invBenP); |
346 | trackParam->SetBendingSlope(benC); | |
347 | trackParam->SetNonBendingSlope(nonBenC); | |
348 | if (fFitNParam == 5) { | |
349 | trackParam->SetNonBendingCoor(x); | |
350 | trackParam->SetBendingCoor(y); | |
a9e2aefa | 351 | } |
8429a5e4 | 352 | // global result of the fit |
353 | Double_t fedm, errdef; | |
354 | Int_t npari, nparx; | |
355 | fgFitter->GetStats(fFitFMin, fedm, errdef, npari, nparx); | |
a9e2aefa | 356 | } |
357 | ||
358 | //__________________________________________________________________________ | |
359 | void AliMUONTrack::AddSegment(AliMUONSegment* Segment) | |
360 | { | |
8429a5e4 | 361 | // Add Segment to the track |
a9e2aefa | 362 | AddHitForRec(Segment->GetHitForRec1()); // 1st hit |
363 | AddHitForRec(Segment->GetHitForRec2()); // 2nd hit | |
364 | } | |
365 | ||
366 | //__________________________________________________________________________ | |
367 | void AliMUONTrack::AddHitForRec(AliMUONHitForRec* HitForRec) | |
368 | { | |
8429a5e4 | 369 | // Add HitForRec to the track: |
370 | // actual TrackHit into TClonesArray of TrackHit's for the event; | |
371 | // pointer to actual TrackHit in TObjArray of pointers to TrackHit's for the track | |
372 | TClonesArray *recTrackHitsPtr = this->fEventReconstructor->GetRecTrackHitsPtr(); | |
373 | Int_t eventTrackHits = this->fEventReconstructor->GetNRecTrackHits(); | |
374 | // event | |
375 | AliMUONTrackHit* trackHit = | |
376 | new ((*recTrackHitsPtr)[eventTrackHits]) AliMUONTrackHit(HitForRec); | |
377 | this->fEventReconstructor->SetNRecTrackHits(eventTrackHits + 1); | |
378 | // track | |
379 | fTrackHitsPtr->Add(trackHit); | |
a9e2aefa | 380 | fNTrackHits++; |
381 | } | |
382 | ||
383 | //__________________________________________________________________________ | |
384 | void AliMUONTrack::SetTrackParamAtHit(Int_t indexHit, AliMUONTrackParam *TrackParam) | |
385 | { | |
386 | // Set track parameters at TrackHit with index "indexHit" | |
387 | // from the track parameters pointed to by "TrackParam". | |
388 | AliMUONTrackHit* trackHit = (AliMUONTrackHit*) ((*fTrackHitsPtr)[indexHit]); | |
389 | trackHit->SetTrackParam(TrackParam); | |
390 | } | |
391 | ||
392 | //__________________________________________________________________________ | |
393 | void AliMUONTrack::SetTrackParamAtVertex() | |
394 | { | |
395 | // Set track parameters at vertex. | |
396 | // TrackHit's are assumed to be only in stations(1..) 4 and 5, | |
397 | // and sorted according to increasing Z.. | |
398 | // Parameters are calculated from information in HitForRec's | |
399 | // of first and last TrackHit's. | |
400 | AliMUONTrackParam *trackParam = | |
401 | &fTrackParamAtVertex; // pointer to track parameters | |
402 | // Pointer to HitForRec of first TrackHit | |
403 | AliMUONHitForRec *firstHit = | |
404 | ((AliMUONTrackHit*) (fTrackHitsPtr->First()))->GetHitForRecPtr(); | |
405 | // Pointer to HitForRec of last TrackHit | |
406 | AliMUONHitForRec *lastHit = | |
407 | ((AliMUONTrackHit*) (fTrackHitsPtr->Last()))->GetHitForRecPtr(); | |
408 | // Z difference between first and last hits | |
409 | Double_t deltaZ = firstHit->GetZ() - lastHit->GetZ(); | |
410 | // bending slope in stations(1..) 4 and 5 | |
411 | Double_t bendingSlope = | |
412 | (firstHit->GetBendingCoor() - lastHit->GetBendingCoor()) / deltaZ; | |
413 | trackParam->SetBendingSlope(bendingSlope); | |
414 | // impact parameter | |
415 | Double_t impactParam = | |
416 | firstHit->GetBendingCoor() - bendingSlope * firstHit->GetZ(); // same if from firstHit and lastHit ???? | |
417 | // signed bending momentum | |
418 | Double_t signedBendingMomentum = | |
419 | fEventReconstructor->GetBendingMomentumFromImpactParam(impactParam); | |
420 | trackParam->SetInverseBendingMomentum(1.0 / signedBendingMomentum); | |
421 | // bending slope at vertex | |
422 | trackParam-> | |
423 | SetBendingSlope(bendingSlope + | |
424 | impactParam / fEventReconstructor->GetSimpleBPosition()); | |
425 | // non bending slope | |
426 | Double_t nonBendingSlope = | |
427 | (firstHit->GetNonBendingCoor() - lastHit->GetNonBendingCoor()) / deltaZ; | |
428 | trackParam->SetNonBendingSlope(nonBendingSlope); | |
429 | // vertex coordinates at (0,0,0) | |
430 | trackParam->SetZ(0.0); | |
431 | trackParam->SetBendingCoor(0.0); | |
432 | trackParam->SetNonBendingCoor(0.0); | |
433 | } | |
434 | ||
435 | //__________________________________________________________________________ | |
436 | void TrackChi2(Int_t &NParam, Double_t *Gradient, Double_t &Chi2, Double_t *Param, Int_t Flag) | |
437 | { | |
438 | // Return the "Chi2" to be minimized with Minuit for track fitting, | |
439 | // with "NParam" parameters | |
440 | // and their current values in array pointed to by "Param". | |
441 | // Assumes that the track hits are sorted according to increasing Z. | |
442 | // Track parameters at each TrackHit are updated accordingly. | |
04b5ea16 | 443 | // Multiple Coulomb scattering is not taken into account |
956019b6 | 444 | AliMUONTrack *trackBeingFitted; |
a9e2aefa | 445 | AliMUONTrackHit* hit; |
446 | AliMUONTrackParam param1; | |
447 | Int_t hitNumber; | |
448 | Double_t zHit; | |
449 | Chi2 = 0.0; // initialize Chi2 | |
450 | // copy of track parameters to be fitted | |
956019b6 | 451 | trackBeingFitted = (AliMUONTrack*) AliMUONTrack::Fitter()->GetObjectFit(); |
452 | if (trackBeingFitted->GetFitStart() == 0) | |
453 | param1 = *(trackBeingFitted->GetTrackParamAtVertex()); | |
454 | else param1 = *(trackBeingFitted->GetTrackParamAtFirstHit()); | |
a9e2aefa | 455 | // Minuit parameters to be fitted into this copy |
456 | param1.SetInverseBendingMomentum(Param[0]); | |
457 | param1.SetBendingSlope(Param[1]); | |
458 | param1.SetNonBendingSlope(Param[2]); | |
459 | if (NParam == 5) { | |
460 | param1.SetNonBendingCoor(Param[3]); | |
461 | param1.SetBendingCoor(Param[4]); | |
462 | } | |
463 | // Follow track through all planes of track hits | |
464 | for (hitNumber = 0; hitNumber < trackBeingFitted->GetNTrackHits(); hitNumber++) { | |
465 | hit = (AliMUONTrackHit*) (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber]; | |
466 | zHit = hit->GetHitForRecPtr()->GetZ(); | |
467 | // do something special if 2 hits with same Z ???? | |
468 | // security against infinite loop ???? | |
469 | (¶m1)->ExtrapToZ(zHit); // extrapolation | |
470 | hit->SetTrackParam(¶m1); | |
471 | // Increment Chi2 | |
472 | // done hit per hit, with hit resolution, | |
473 | // and not with point and angle like in "reco_muon.F" !!!! | |
474 | // Needs to add multiple scattering contribution ???? | |
475 | Double_t dX = | |
476 | hit->GetHitForRecPtr()->GetNonBendingCoor() - (¶m1)->GetNonBendingCoor(); | |
477 | Double_t dY = | |
478 | hit->GetHitForRecPtr()->GetBendingCoor() - (¶m1)->GetBendingCoor(); | |
479 | Chi2 = | |
480 | Chi2 + | |
481 | dX * dX / hit->GetHitForRecPtr()->GetNonBendingReso2() + | |
482 | dY * dY / hit->GetHitForRecPtr()->GetBendingReso2(); | |
483 | } | |
484 | } | |
04b5ea16 | 485 | |
486 | //__________________________________________________________________________ | |
487 | void TrackChi2MCS(Int_t &NParam, Double_t *Gradient, Double_t &Chi2, Double_t *Param, Int_t Flag) | |
488 | { | |
489 | // Return the "Chi2" to be minimized with Minuit for track fitting, | |
490 | // with "NParam" parameters | |
491 | // and their current values in array pointed to by "Param". | |
492 | // Assumes that the track hits are sorted according to increasing Z. | |
493 | // Track parameters at each TrackHit are updated accordingly. | |
494 | // Multiple Coulomb scattering is taken into account with covariance matrix. | |
956019b6 | 495 | AliMUONTrack *trackBeingFitted; |
04b5ea16 | 496 | AliMUONTrackParam param1; |
497 | Chi2 = 0.0; // initialize Chi2 | |
498 | // copy of track parameters to be fitted | |
956019b6 | 499 | trackBeingFitted = (AliMUONTrack*) AliMUONTrack::Fitter()->GetObjectFit(); |
500 | if (trackBeingFitted->GetFitStart() == 0) | |
501 | param1 = *(trackBeingFitted->GetTrackParamAtVertex()); | |
502 | else param1 = *(trackBeingFitted->GetTrackParamAtFirstHit()); | |
04b5ea16 | 503 | // Minuit parameters to be fitted into this copy |
504 | param1.SetInverseBendingMomentum(Param[0]); | |
505 | param1.SetBendingSlope(Param[1]); | |
506 | param1.SetNonBendingSlope(Param[2]); | |
507 | if (NParam == 5) { | |
508 | param1.SetNonBendingCoor(Param[3]); | |
509 | param1.SetBendingCoor(Param[4]); | |
510 | } | |
511 | ||
956019b6 | 512 | AliMUONTrackHit *hit; |
513 | Bool_t goodDeterminant; | |
eb9c9dab | 514 | Int_t chCurrent, chPrev, hitNumber, hitNumber1, hitNumber2, hitNumber3; |
515 | Double_t z, z1, z2, z3; | |
516 | AliMUONTrackHit *hit1, *hit2, *hit3; | |
517 | Double_t hbc1, hbc2, pbc1, pbc2; | |
518 | Double_t hnbc1, hnbc2, pnbc1, pnbc2; | |
519 | Int_t numberOfHit = trackBeingFitted->GetNTrackHits(); | |
04b5ea16 | 520 | TMatrix *covBending = new TMatrix(numberOfHit, numberOfHit); |
521 | TMatrix *covNonBending = new TMatrix(numberOfHit, numberOfHit); | |
eb9c9dab | 522 | Double_t *msa2 = new Double_t[numberOfHit]; |
04b5ea16 | 523 | |
524 | // Predicted coordinates and multiple scattering angles are first calculated | |
525 | for (hitNumber = 0; hitNumber < numberOfHit; hitNumber++) { | |
526 | hit = (AliMUONTrackHit*) (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber]; | |
eb9c9dab | 527 | z = hit->GetHitForRecPtr()->GetZ(); |
04b5ea16 | 528 | // do something special if 2 hits with same Z ???? |
529 | // security against infinite loop ???? | |
eb9c9dab | 530 | (¶m1)->ExtrapToZ(z); // extrapolation |
04b5ea16 | 531 | hit->SetTrackParam(¶m1); |
eb9c9dab | 532 | // square of multiple scattering angle at current hit, with one chamber |
533 | msa2[hitNumber] = MultipleScatteringAngle2(hit); | |
534 | // correction for eventual missing hits or multiple hits in a chamber, | |
535 | // according to the number of chambers | |
536 | // between the current hit and the previous one | |
537 | chCurrent = hit->GetHitForRecPtr()->GetChamberNumber(); | |
538 | if (hitNumber > 0) msa2[hitNumber] = msa2[hitNumber] * (chCurrent - chPrev); | |
539 | chPrev = chCurrent; | |
04b5ea16 | 540 | } |
541 | ||
542 | // Calculates the covariance matrix | |
eb9c9dab | 543 | for (hitNumber1 = 0; hitNumber1 < numberOfHit; hitNumber1++) { |
544 | hit1 = (AliMUONTrackHit*) (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber1]; | |
545 | z1 = hit1->GetHitForRecPtr()->GetZ(); | |
04b5ea16 | 546 | for (hitNumber2 = hitNumber1; hitNumber2 < numberOfHit; hitNumber2++) { |
eb9c9dab | 547 | hit2 = (AliMUONTrackHit*) (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber2]; |
548 | z2 = hit2->GetHitForRecPtr()->GetZ(); | |
956019b6 | 549 | // initialization to 0 (diagonal plus upper triangular part) |
550 | (*covBending)(hitNumber2, hitNumber1) = 0.0; | |
551 | // contribution from multiple scattering in bending plane: | |
552 | // loop over upstream hits | |
553 | for (hitNumber3 = 0; hitNumber3 < hitNumber1; hitNumber3++) { | |
eb9c9dab | 554 | hit3 = (AliMUONTrackHit*) |
555 | (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber3]; | |
556 | z3 = hit3->GetHitForRecPtr()->GetZ(); | |
04b5ea16 | 557 | (*covBending)(hitNumber2, hitNumber1) = |
558 | (*covBending)(hitNumber2, hitNumber1) + | |
eb9c9dab | 559 | ((z1 - z3) * (z2 - z3) * msa2[hitNumber3]); |
956019b6 | 560 | } |
561 | // equal contribution from multiple scattering in non bending plane | |
04b5ea16 | 562 | (*covNonBending)(hitNumber2, hitNumber1) = |
563 | (*covBending)(hitNumber2, hitNumber1); | |
956019b6 | 564 | if (hitNumber1 == hitNumber2) { |
565 | // Diagonal elements: add contribution from position measurements | |
566 | // in bending plane | |
567 | (*covBending)(hitNumber2, hitNumber1) = | |
eb9c9dab | 568 | (*covBending)(hitNumber2, hitNumber1) + |
569 | hit1->GetHitForRecPtr()->GetBendingReso2(); | |
956019b6 | 570 | // and in non bending plane |
04b5ea16 | 571 | (*covNonBending)(hitNumber2, hitNumber1) = |
eb9c9dab | 572 | (*covNonBending)(hitNumber2, hitNumber1) + |
573 | hit1->GetHitForRecPtr()->GetNonBendingReso2(); | |
956019b6 | 574 | } |
575 | else { | |
576 | // Non diagonal elements: symmetrization | |
577 | // for bending plane | |
578 | (*covBending)(hitNumber1, hitNumber2) = | |
579 | (*covBending)(hitNumber2, hitNumber1); | |
580 | // and non bending plane | |
581 | (*covNonBending)(hitNumber1, hitNumber2) = | |
582 | (*covNonBending)(hitNumber2, hitNumber1); | |
583 | } | |
584 | } // for (hitNumber2 = hitNumber1;... | |
585 | } // for (hitNumber1 = 0;... | |
04b5ea16 | 586 | |
587 | // Inverts covariance matrix | |
956019b6 | 588 | goodDeterminant = kTRUE; |
589 | // check whether the Invert method returns flag if matrix cannot be inverted, | |
590 | // and do not calculate the Determinant in that case !!!! | |
04b5ea16 | 591 | if (covBending->Determinant() != 0) { |
592 | covBending->Invert(); | |
593 | } else { | |
956019b6 | 594 | goodDeterminant = kFALSE; |
04b5ea16 | 595 | cout << "Warning in ChiMCS Determinant Bending=0: " << endl; |
596 | } | |
956019b6 | 597 | if (covNonBending->Determinant() != 0) { |
04b5ea16 | 598 | covNonBending->Invert(); |
599 | } else { | |
956019b6 | 600 | goodDeterminant = kFALSE; |
04b5ea16 | 601 | cout << "Warning in ChiMCS Determinant non Bending=0: " << endl; |
602 | } | |
956019b6 | 603 | |
604 | // It would be worth trying to calculate the inverse of the covariance matrix | |
605 | // only once per fit, since it cannot change much in principle, | |
606 | // and it would save a lot of computing time !!!! | |
04b5ea16 | 607 | |
608 | // Calculates Chi2 | |
eb9c9dab | 609 | if (goodDeterminant) { |
610 | // with Multiple Scattering if inversion correct | |
611 | for (hitNumber1 = 0; hitNumber1 < numberOfHit ; hitNumber1++) { | |
612 | hit1 = (AliMUONTrackHit*) (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber1]; | |
613 | hbc1 = hit1->GetHitForRecPtr()->GetBendingCoor(); | |
614 | pbc1 = hit1->GetTrackParam()->GetBendingCoor(); | |
615 | hnbc1 = hit1->GetHitForRecPtr()->GetNonBendingCoor(); | |
616 | pnbc1 = hit1->GetTrackParam()->GetNonBendingCoor(); | |
617 | for (hitNumber2 = 0; hitNumber2 < numberOfHit; hitNumber2++) { | |
618 | hit2 = (AliMUONTrackHit*) | |
619 | (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber2]; | |
620 | hbc2 = hit2->GetHitForRecPtr()->GetBendingCoor(); | |
621 | pbc2 = hit2->GetTrackParam()->GetBendingCoor(); | |
622 | hnbc2 = hit2->GetHitForRecPtr()->GetNonBendingCoor(); | |
623 | pnbc2 = hit2->GetTrackParam()->GetNonBendingCoor(); | |
04b5ea16 | 624 | Chi2 = Chi2 + |
eb9c9dab | 625 | ((*covBending)(hitNumber2, hitNumber1) * |
626 | (hbc1 - pbc1) * (hbc2 - pbc2)) + | |
04b5ea16 | 627 | ((*covNonBending)(hitNumber2, hitNumber1) * |
eb9c9dab | 628 | (hnbc1 - pnbc1) * (hnbc2 - pnbc2)); |
04b5ea16 | 629 | } |
630 | } | |
eb9c9dab | 631 | } else { |
632 | // without Multiple Scattering if inversion impossible | |
633 | for (hitNumber1 = 0; hitNumber1 < numberOfHit ; hitNumber1++) { | |
634 | hit1 = (AliMUONTrackHit*) (*(trackBeingFitted->GetTrackHitsPtr()))[hitNumber1]; | |
635 | hbc1 = hit1->GetHitForRecPtr()->GetBendingCoor(); | |
636 | pbc1 = hit1->GetTrackParam()->GetBendingCoor(); | |
637 | hnbc1 = hit1->GetHitForRecPtr()->GetNonBendingCoor(); | |
638 | pnbc1 = hit1->GetTrackParam()->GetNonBendingCoor(); | |
639 | Chi2 = Chi2 + | |
640 | ((hbc1 - pbc1) * (hbc1 - pbc1) / | |
641 | hit1->GetHitForRecPtr()->GetBendingReso2()) + | |
642 | ((hnbc1 - pnbc1) * (hnbc1 - pnbc1) / | |
643 | hit1->GetHitForRecPtr()->GetNonBendingReso2()); | |
04b5ea16 | 644 | } |
645 | } | |
646 | ||
647 | delete covBending; | |
648 | delete covNonBending; | |
eb9c9dab | 649 | delete [] msa2; |
04b5ea16 | 650 | } |
651 | ||
652 | Double_t MultipleScatteringAngle2(AliMUONTrackHit *TrackHit) | |
653 | { | |
654 | // Returns square of multiple Coulomb scattering angle | |
655 | // at TrackHit pointed to by "TrackHit" | |
656 | Double_t slopeBending, slopeNonBending, radiationLength, inverseBendingMomentum2, inverseTotalMomentum2; | |
657 | Double_t varMultipleScatteringAngle; | |
956019b6 | 658 | AliMUONTrack *trackBeingFitted = (AliMUONTrack*) AliMUONTrack::Fitter()->GetObjectFit(); |
04b5ea16 | 659 | AliMUONTrackParam *param = TrackHit->GetTrackParam(); |
956019b6 | 660 | // Better implementation in AliMUONTrack class ???? |
04b5ea16 | 661 | slopeBending = param->GetBendingSlope(); |
662 | slopeNonBending = param->GetNonBendingSlope(); | |
663 | // thickness in radiation length for the current track, | |
664 | // taking local angle into account | |
665 | radiationLength = | |
666 | trackBeingFitted->GetEventReconstructor()->GetChamberThicknessInX0() * | |
667 | TMath::Sqrt(1.0 + | |
668 | slopeBending * slopeBending + slopeNonBending * slopeNonBending); | |
669 | inverseBendingMomentum2 = | |
670 | param->GetInverseBendingMomentum() * param->GetInverseBendingMomentum(); | |
671 | inverseTotalMomentum2 = | |
956019b6 | 672 | inverseBendingMomentum2 * (1.0 + slopeBending * slopeBending) / |
04b5ea16 | 673 | (1.0 + slopeBending *slopeBending + slopeNonBending * slopeNonBending); |
674 | varMultipleScatteringAngle = 0.0136 * (1.0 + 0.038 * TMath::Log(radiationLength)); | |
956019b6 | 675 | // The velocity is assumed to be 1 !!!! |
04b5ea16 | 676 | varMultipleScatteringAngle = inverseTotalMomentum2 * radiationLength * |
677 | varMultipleScatteringAngle * varMultipleScatteringAngle; | |
678 | return varMultipleScatteringAngle; | |
679 | } |