1 /**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
7 * Permission to use, copy, modify and distribute this software and its *
8 * documentation strictly for non-commercial purposes is hereby granted *
9 * without fee, provided that the above copyright notice appears in all *
10 * copies and that both the copyright notice and this permission notice *
11 * appear in the supporting documentation. The authors make no claims *
12 * about the suitability of this software for any purpose. It is *
13 * provided "as is" without express or implied warranty. *
14 **************************************************************************/
18 Revision 1.7 2001/02/08 10:34:41 gosset
19 Add a "real" default constructor.
21 Revision 1.6 2001/02/05 14:49:29 hristov
22 Compare() declared const (R.Brun)
24 Revision 1.5 2001/01/08 11:01:02 gosset
25 Modifications used for addendum to Dimuon TDR (JP Cussonneau):
26 *. MaxBendingMomentum to make both a segment and a track (default 500)
27 *. MaxChi2 per degree of freedom to make a track (default 100)
28 *. MinBendingMomentum used also to make a track
29 and not only a segment (default 3)
30 *. wider roads for track search in stations 1 to 3
31 *. extrapolation to actual Z instead of Z(chamber) in FollowTracks
33 - limits on parameters X and Y (+/-500)
34 - covariance matrices in double precision
35 - normalization of covariance matrices before inversion
36 - suppression of Minuit printouts
37 *. correction against memory leak (delete extrapHit) in FollowTracks
38 *. RMax to 10 degrees with Z(chamber) instead of fixed values;
39 RMin and Rmax cuts suppressed in NewHitForRecFromGEANT,
40 because useless with realistic geometry
42 Revision 1.4 2000/06/30 10:15:48 gosset
43 Changes to EventReconstructor...:
44 precision fit with multiple Coulomb scattering;
45 extrapolation to vertex with Branson correction in absorber (JPC)
47 Revision 1.3 2000/06/25 13:06:39 hristov
48 Inline functions moved from *.cxx to *.h files instead of forward declarations
50 Revision 1.2 2000/06/15 07:58:48 morsch
51 Code from MUON-dev joined
53 Revision 1.1.2.4 2000/06/12 10:10:21 morsch
54 Dummy copy constructor and assignment operator added
56 Revision 1.1.2.3 2000/06/09 21:01:16 morsch
57 Make includes consistent with new file structure.
59 Revision 1.1.2.2 2000/06/09 12:58:05 gosset
60 Removed comment beginnings in Log sections of .cxx files
61 Suppressed most violations of coding rules
63 Revision 1.1.2.1 2000/06/07 14:44:53 gosset
64 Addition of files for track reconstruction in C++
67 ///////////////////////////////////////////////////////////
69 // Segment for reconstruction
74 // two hits for reconstruction in the two chambers of one station
76 ///////////////////////////////////////////////////////////
79 #include "AliMUONChamber.h"
80 #include "AliMUONHitForRec.h"
81 #include "AliMUONSegment.h"
82 #include "AliMUONTrackParam.h"
83 #include "AliRun.h" // for gAlice
85 ClassImp(AliMUONSegment) // Class implementation in ROOT context
87 //__________________________________________________________________________
88 AliMUONSegment::AliMUONSegment()
90 // Default constructor
91 fHitForRecPtr1 = 0; // pointer to HitForRec in first chamber
92 fHitForRecPtr2 = 0; // pointer to HitForRec in second chamber
94 fBendingCoor = 0.0; // Coordinate in bending plane
95 fBendingSlope = 0.0; // Slope in bending plane
96 // Covariance in bending plane:
97 fBendingCoorReso2 = 0.0; // Covariance(coordinate C1 in first chamber)
98 fBendingSlopeReso2 = 0.0; // Covariance(slope)
99 fBendingCoorSlopeReso2 = 0.0; // Covariance(C1,slope)
100 fBendingImpact = 0.0; // Impact parameter in bending plane
101 // Non Bending plane:
102 fNonBendingCoor = 0.0; // Coordinate in non bending plane
103 fNonBendingSlope = 0.0; // Slope in non bending plane
104 // Covariance in non bending plane:
105 fNonBendingCoorReso2 = 0.0; // Covariance(coordinate C1 in first chamber)
106 fNonBendingSlopeReso2 = 0.0; // Covariance(slope)
107 fNonBendingCoorSlopeReso2 = 0.0; // Covariance(C1,slope)
108 fNonBendingImpact = 0.0; // Impact parameter in non bending plane
109 fInTrack = kFALSE; // TRUE if segment belongs to one track
112 //__________________________________________________________________________
113 AliMUONSegment::AliMUONSegment(AliMUONHitForRec* Hit1, AliMUONHitForRec* Hit2)
115 // Constructor for AliMUONSegment from two HitForRec's,
116 // one, in the first chamber of the station, pointed to by "Hit1",
117 // the other one, in the second chamber of the station, pointed to by "Hit1".
118 // Fills the pointers to both hits,
119 // the slope, the covariance for (coordinate in first chamber, slope),
120 // and the impact parameter at vertex (Z=0),
121 // in bending and non bending planes.
122 // Puts the "fInTrack" flag to "kFALSE".
124 // pointers to HitForRec's
125 fHitForRecPtr1 = Hit1;
126 fHitForRecPtr2 = Hit2;
127 dz = Hit1->GetZ() - Hit2->GetZ();
129 fBendingCoor = Hit1->GetBendingCoor();
130 fBendingSlope = (fBendingCoor - Hit2->GetBendingCoor()) / dz;
131 fBendingImpact = fBendingCoor - Hit1->GetZ() * fBendingSlope;
132 fBendingCoorReso2 = Hit1->GetBendingReso2();
133 fBendingSlopeReso2 = ( Hit1->GetBendingReso2() +
134 Hit2->GetBendingReso2() ) / dz / dz;
135 fBendingCoorSlopeReso2 = Hit1->GetBendingReso2() / dz;
137 fNonBendingCoor = Hit1->GetNonBendingCoor();
138 fNonBendingSlope = (fNonBendingCoor - Hit2->GetNonBendingCoor()) / dz;
139 fNonBendingImpact = fNonBendingCoor - Hit1->GetZ() * fNonBendingSlope;
140 fNonBendingCoorReso2 = Hit1->GetNonBendingReso2();
141 fNonBendingSlopeReso2 = ( Hit1->GetNonBendingReso2() +
142 Hit2->GetNonBendingReso2() ) / dz / dz;
143 fNonBendingCoorSlopeReso2 = Hit1->GetNonBendingReso2() / dz;
144 // "fInTrack" flag to "kFALSE"
149 AliMUONSegment::AliMUONSegment (const AliMUONSegment& MUONSegment)
151 // Dummy copy constructor
154 AliMUONSegment & AliMUONSegment::operator=(const AliMUONSegment& MUONSegment)
156 // Dummy assignment operator
160 //__________________________________________________________________________
161 Int_t AliMUONSegment::Compare(const TObject* Segment) const
163 // "Compare" function to sort with increasing absolute value
164 // of the "impact parameter" in bending plane.
165 // Returns -1 (0, +1) if |impact parameter| of current Segment
166 // is smaller than (equal to, larger than) |impact parameter| of Segment
167 if (TMath::Abs(((AliMUONSegment*)this)->fBendingSlope)
168 < TMath::Abs(((AliMUONSegment*)Segment)->fBendingSlope))
170 // continuous parameter, hence no need for testing equal case
174 //__________________________________________________________________________
175 Double_t AliMUONSegment::NormalizedChi2WithSegment(AliMUONSegment* Segment, Double_t Sigma2Cut)
177 // Calculate the normalized Chi2 between the current Segment (this)
178 // and the Segment pointed to by "Segment",
179 // i.e. the square deviations between the coordinates and the slopes,
180 // in both the bending and the non bending plane,
181 // divided by the variance of the same quantities and by "Sigma2Cut".
182 // Returns 5 if none of the 4 quantities is OK,
183 // something smaller than or equal to 4 otherwise.
184 // Would it be more correct to use a real chi square
185 // including the non diagonal term ????
186 Double_t chi2, chi2Max, diff, normDiff;
189 // coordinate in bending plane
190 diff = this->fBendingCoor - Segment->fBendingCoor;
191 normDiff = diff * diff /
192 (this->fBendingCoorReso2 + Segment->fBendingCoorReso2) / Sigma2Cut;
193 if (normDiff > 1.0) return chi2Max;
194 chi2 = chi2 + normDiff;
195 // slope in bending plane
196 diff = this->fBendingSlope - Segment->fBendingSlope;
197 normDiff = diff * diff /
198 (this->fBendingSlopeReso2 + Segment->fBendingSlopeReso2) / Sigma2Cut;
199 if (normDiff > 1.0) return chi2Max;
200 chi2 = chi2 + normDiff;
201 // coordinate in non bending plane
202 diff = this->fNonBendingCoor - Segment->fNonBendingCoor;
203 normDiff = diff * diff /
204 (this->fNonBendingCoorReso2 + Segment->fNonBendingCoorReso2) / Sigma2Cut;
205 if (normDiff > 1.0) return chi2Max;
206 chi2 = chi2 + normDiff;
207 // slope in non bending plane
208 diff = this->fNonBendingSlope - Segment->fNonBendingSlope;
209 normDiff = diff * diff /
210 (this->fNonBendingSlopeReso2 + Segment->fNonBendingSlopeReso2) / Sigma2Cut;
211 if (normDiff > 1.0) return chi2Max;
212 chi2 = chi2 + normDiff;
216 //__________________________________________________________________________
217 AliMUONSegment* AliMUONSegment::CreateSegmentFromLinearExtrapToStation (Int_t Station, Double_t MCSfactor)
219 // Extrapolates linearly the current Segment (this) to station (0..) "Station".
220 // Multiple Coulomb scattering calculated from "MCSfactor"
221 // corresponding to one chamber,
222 // with one chamber for the coordinate, two chambers for the angle,
223 // due to the arrangement in stations.
224 // Valid from station(1..) 4 to 5 or vice versa.
225 // Returns the pointer to the created AliMUONSegment object
226 // corresponding to this extrapolation.
227 // The caller has the responsibility to delete this object.
228 AliMUONSegment* extrapSegment = new AliMUONSegment(); // creates empty new segment
229 // dZ from first hit of current Segment to first chamber of station "Station"
230 AliMUON *pMUON = (AliMUON*) gAlice->GetModule("MUON"); // necessary ????
232 (&(pMUON->Chamber(2 * Station)))->Z() - (this->fHitForRecPtr1)->GetZ();
233 // Data in bending plane
235 extrapSegment->fBendingCoor = this->fBendingCoor + this->fBendingSlope * dZ;
237 extrapSegment->fBendingSlope = this->fBendingSlope;
238 // covariance, including multiple Coulomb scattering over dZ due to one chamber
239 extrapSegment->fBendingCoorReso2 = this->fBendingCoorReso2 +
240 (this->fBendingSlopeReso2 + MCSfactor) * dZ * dZ; // missing non diagonal term: "2.0 * this->fBendingCoorSlopeReso2 * dZ" !!!!
241 extrapSegment->fBendingSlopeReso2 = this->fBendingSlopeReso2 + 2.0 * MCSfactor;
242 extrapSegment->fBendingCoorSlopeReso2 =
243 this->fBendingCoorSlopeReso2 + this->fBendingSlopeReso2 * dZ; // missing: contribution from multiple Coulomb scattering !!!!
244 // Data in non bending plane
246 extrapSegment->fNonBendingCoor =
247 this->fNonBendingCoor + this->fNonBendingSlope * dZ;
249 extrapSegment->fNonBendingSlope = this->fNonBendingSlope;
250 // covariance, including multiple Coulomb scattering over dZ due to one chamber
251 extrapSegment->fNonBendingCoorReso2 = this->fNonBendingCoorReso2 +
252 (this->fNonBendingSlopeReso2 + MCSfactor) *dZ * dZ; // missing non diagonal term: "2.0 * this->fNonBendingCoorSlopeReso2 * dZ" !!!!
253 extrapSegment->fNonBendingSlopeReso2 =
254 this->fNonBendingSlopeReso2 + 2.0 * MCSfactor;
255 extrapSegment->fNonBendingCoorSlopeReso2 =
256 this->fNonBendingCoorSlopeReso2 + this->fNonBendingSlopeReso2 * dZ; // missing: contribution from multiple Coulomb scattering !!!!
257 return extrapSegment;
260 //__________________________________________________________________________
261 AliMUONHitForRec* AliMUONSegment::CreateHitForRecFromLinearExtrapToChamber (Int_t Chamber, Double_t MCSfactor)
263 // Extrapolates linearly the current Segment (this) to chamber(0..) "Chamber".
264 // Multiple Coulomb scattering calculated from "MCSfactor"
265 // corresponding to one chamber.
266 // Valid from station(1..) 4 to 5 or vice versa.
267 // Returns the pointer to the created AliMUONHitForRec object
268 // corresponding to this extrapolation.
269 // The caller has the responsibility to delete this object.
270 AliMUONHitForRec* extrapHitForRec = new AliMUONHitForRec(); // creates empty new HitForRec
271 // dZ from first hit of current Segment to chamber
272 AliMUON *pMUON = (AliMUON*) gAlice->GetModule("MUON"); // necessary ????
274 (&(pMUON->Chamber(Chamber)))->Z() - (this->fHitForRecPtr1)->GetZ();
275 // Data in bending plane
277 extrapHitForRec->SetBendingCoor(this->fBendingCoor + this->fBendingSlope * dZ);
278 // covariance, including multiple Coulomb scattering over dZ due to one chamber
279 extrapHitForRec->SetBendingReso2(this->fBendingCoorReso2 +
280 (this->fBendingSlopeReso2 + MCSfactor) * dZ * dZ); // missing non diagonal term: "2.0 * this->fBendingCoorSlopeReso2 * dZ" !!!!
281 // Data in non bending plane
283 extrapHitForRec ->SetNonBendingCoor(this->fNonBendingCoor +
284 this->fNonBendingSlope * dZ);
285 // covariance, including multiple Coulomb scattering over dZ due to one chamber
287 SetNonBendingReso2(this->fNonBendingCoorReso2 +
288 (this->fNonBendingSlopeReso2 + MCSfactor) * dZ * dZ); // missing non diagonal term: "2.0 * this->fNonBendingCoorSlopeReso2 * dZ" !!!!
289 return extrapHitForRec;
292 //__________________________________________________________________________
293 void AliMUONSegment::UpdateFromStationTrackParam(AliMUONTrackParam *TrackParam, Double_t MCSfactor, Double_t Dz1, Double_t Dz2, Double_t Dz3, Int_t Station, Double_t InverseMomentum)
295 // Fill data members with values calculated from the array of track parameters
296 // pointed to by "TrackParam" (index = 0 and 1 for first and second chambers
297 // of the station, respectively).
298 // Multiple Coulomb scattering is taking into account with "MCSfactor"
299 // corresponding to one chamber,
300 // with one chamber for the coordinate, two chambers for the angle,
301 // due to the arrangement in stations.
302 // Resolution coming from:
303 // coordinate in closest station at "Dz1" from current "Station",
304 // slope between closest stations, with "Dz2" interval between them,
305 // interval "Dz3" between chambers of closest station,
306 // extrapolation over "Dz1" from closest station,
307 // "InverseMomentum".
308 // When called, "fBendingCoorReso2" and "fNonBendingCoorReso2"
309 // are assumed to be filled
310 // with the variance on bending and non bending coordinates.
311 // The "road" is parametrized from the old reco_muon.F
312 // with 8 cm between stations.
313 AliMUONTrackParam *param0;
314 // Double_t cReso2, sReso2;
315 // parameters to define the widths of the searching roads in station 0,1,2
316 // width = p0 + p1/ (momentum)^2
317 // station number: 0 1 2
318 // static Double_t p0BendingCoor[3] = { 6.43e-2, 1.64e-2, 0.034 };
319 // static Double_t p1BendingCoor[3] = { 986., 821., 446. };
320 // static Double_t p0BendingSlope[3] = { 3.54e-6, 3.63e-6, 3.6e-6 };
321 // static Double_t p1BendingSlope[3] = { 4.49e-3, 4.8e-3, 0.011 };
322 // static Double_t p0NonBendingCoor[3] = { 4.66e-2, 4.83e-2, 0.049 };
323 // static Double_t p1NonBendingCoor[3] = { 1444., 866., 354. };
324 // static Double_t p0NonBendingSlope[3] = { 6.14e-4, 6.49e-4, 6.85e-4 };
325 // static Double_t p1NonBendingSlope[3] = { 0., 0., 0. };
327 static Double_t p0BendingCoor[3] = { 6.43e-2, 6.43e-2, 6.43e-2 };
328 static Double_t p1BendingCoor[3] = { 986., 986., 986. };
329 static Double_t p0BendingSlope[3] = { 3.6e-6, 3.6e-6, 3.6e-6 };
330 static Double_t p1BendingSlope[3] = { 1.1e-2, 1.1e-2, 1.1e-2 };
331 static Double_t p0NonBendingCoor[3] = { 0.049, 0.049, 0.049 };
332 static Double_t p1NonBendingCoor[3] = { 1444., 1444., 1444. };
333 static Double_t p0NonBendingSlope[3] = { 6.8e-4, 6.8e-4, 6.8e-4 };
334 static Double_t p1NonBendingSlope[3] = { 0., 0., 0. };
335 param0 = &(TrackParam[0]);
339 // fBendingCoor = param0->GetBendingCoor(); // coordinate
340 // fBendingSlope = param0->GetBendingSlope(); // slope
341 // cReso2 = fBendingCoorReso2;
342 // sReso2 = 2.0 * cReso2 / Dz2 / Dz2;
343 // fBendingCoorReso2 = cReso2 + (sReso2 + MCSfactor) * Dz1 * Dz1;
344 // fBendingSlopeReso2 = sReso2 + 2.0 * MCSfactor;
345 // // Non bending plane
346 // fNonBendingCoor = param0->GetNonBendingCoor(); // coordinate
347 // fNonBendingSlope = param0->GetNonBendingSlope(); // slope
348 // cReso2 = fNonBendingCoorReso2;
349 // sReso2 = 2.0 * cReso2 / Dz2 / Dz2;
350 // fNonBendingCoorReso2 = cReso2 + (sReso2 + MCSfactor) * Dz1 * Dz1;
351 // fNonBendingSlopeReso2 = sReso2 + 2.0 * MCSfactor;
353 // Coordinate and slope
355 fBendingCoor = param0->GetBendingCoor(); // coordinate
356 fBendingSlope = param0->GetBendingSlope(); // slope
358 fNonBendingCoor = param0->GetNonBendingCoor(); // coordinate
359 fNonBendingSlope = param0->GetNonBendingSlope(); // slope
362 // cReso2 and sReso2 have to be subtracted here from the parametrization
363 // because they are added in the functions "NormalizedChi2WithSegment"
364 // and "NormalizedChi2WithHitForRec"
366 // cReso2 = fBendingCoorReso2;
367 // sReso2 = (2. * cReso2 )/ (Dz3*Dz3) ;
368 fBendingCoorReso2 = p0BendingCoor[Station] + p1BendingCoor[Station]*InverseMomentum*InverseMomentum ; // - cReso2
369 fBendingSlopeReso2 = p0BendingSlope[Station] + p1BendingSlope[Station]*InverseMomentum*InverseMomentum; // - sReso2;
371 // cReso2 = fNonBendingCoorReso2;
372 // sReso2 = (2. * cReso2 )/ (Dz3*Dz3) ;
373 fNonBendingCoorReso2 = p0NonBendingCoor[Station] + p1NonBendingCoor[Station]*InverseMomentum*InverseMomentum; // - cReso2;
374 fNonBendingSlopeReso2 = p0NonBendingSlope[Station] + p1NonBendingSlope[Station]*InverseMomentum*InverseMomentum; // - sReso2;
378 // OLD function, with roads automatically calculated instead from being parametrized
379 // kept because it would be a better solution,
380 // if one can really find the right values.
381 // //__________________________________________________________________________
382 // void AliMUONSegment::UpdateFromStationTrackParam(AliMUONTrackParam *TrackParam, Double_t MCSfactor, Double_t Dz1, Double_t Dz2)
384 // // Fill data members with values calculated from the array of track parameters
385 // // pointed to by "TrackParam" (index = 0 and 1 for first and second chambers
386 // // of the station, respectively).
387 // // Multiple Coulomb scattering is taking into account with "MCSfactor"
388 // // corresponding to one chamber,
389 // // with one chamber for the coordinate, two chambers for the angle,
390 // // due to the arrangement in stations.
391 // // Resolution coming from:
392 // // coordinate in closest station at "Dz1",
393 // // slope between closest stations, with "Dz2" interval between them,
394 // // extrapolation over "Dz" from closest station.
395 // // When called, "fBendingCoorReso2" and "fNonBendingCoorReso2"
396 // // are assumed to be filled
397 // // with the variance on bending and non bending coordinates.
398 // AliMUONTrackParam *param0;
399 // Double_t cReso2, sReso2;
400 // param0 = &(TrackParam[0]);
402 // fBendingCoor = param0->GetBendingCoor(); // coordinate
403 // fBendingSlope = param0->GetBendingSlope(); // slope
404 // cReso2 = fBendingCoorReso2;
405 // sReso2 = 2.0 * cReso2 / Dz2 / Dz2;
406 // fBendingCoorReso2 = cReso2 + (sReso2 + MCSfactor) * Dz1 * Dz1;
407 // fBendingSlopeReso2 = sReso2 + 2.0 * MCSfactor;
408 // // Non bending plane
409 // fNonBendingCoor = param0->GetNonBendingCoor(); // coordinate
410 // fNonBendingSlope = param0->GetNonBendingSlope(); // slope
411 // cReso2 = fNonBendingCoorReso2;
412 // sReso2 = 2.0 * cReso2 / Dz2 / Dz2;
413 // fNonBendingCoorReso2 = cReso2 + (sReso2 + MCSfactor) * Dz1 * Dz1;
414 // fNonBendingSlopeReso2 = sReso2 + 2.0 * MCSfactor;