4c039060 |
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 | $Log$ |
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18 | Revision 1.2 1999/09/29 09:24:28 fca |
19 | Introduction of the Copyright and cvs Log |
20 | |
4c039060 |
21 | */ |
22 | |
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23 | /////////////////////////////////////////////////////////////////////////// |
24 | // Class AliTrack |
25 | // Handling of the attributes of a reconstructed particle track. |
26 | // |
27 | // Coding example : |
28 | // ---------------- |
29 | // |
30 | // Float_t a[4]={195.,1.2,-0.04,8.5}; |
31 | // Ali4Vector pmu; |
32 | // pmu.SetVector(a,"car"); |
33 | // AliTrack t1; |
34 | // t1.Set4Momentum(pmu); |
35 | // |
36 | // Float_t b[3]={1.2,-0.04,8.5}; |
37 | // Ali3Vector p; |
38 | // p.SetVector(b,"car"); |
39 | // AliTrack t2; |
40 | // t2.Set3Momentum(p); |
41 | // t2.SetCharge(0); |
42 | // t2.SetMass(1.115); |
43 | // |
44 | // t1.Info(); |
45 | // t2.Info(); |
46 | // |
47 | // Float_t pi=acos(-1.); |
48 | // Float_t thcms=0.2*pi; // decay theta angle in cms |
49 | // Float_t phicms=pi/4.; // decay theta angle in cms |
50 | // Float_t m1=0.938; |
51 | // Float_t m2=0.140; |
52 | // t2.Decay(m1,m2,thcms,phicms); // Track t2 decay : Lambda -> proton + pion |
53 | // |
54 | // t2.List(); |
55 | // |
56 | // Int_t ndec=t2.GetNdecay(); |
57 | // AliTrack* d1=t2.GetDecayTrack(1); // Access to decay track number 1 |
58 | // AliTrack* d2=t2.GetDecayTrack(2); // Access to decay track number 2 |
59 | // |
60 | // AliSignal s1,s2,s3,s4; |
61 | // |
62 | // .... // Code (e.g. detector readout) to fill AliSignal data |
63 | // |
64 | // AliTrack trec; // Track which will be reconstructed from signals |
65 | // trec.AddSignal(s1); |
66 | // trec.AddSignal(s3); |
67 | // trec.AddSignal(s4); |
68 | // |
69 | // Ali3Vector P; |
70 | // Float_t Q,M; |
71 | // |
72 | // ... // Code which accesses signals from trec and reconstructs |
73 | // 3-momentum P, charge Q, mass M etc... |
74 | // |
75 | // trec.Set3Momentum(P); |
76 | // trec.SetCharge(Q); |
77 | // trec.SetMass(M); |
78 | // |
79 | // Float_t r1[3]={1.6,-3.8,25.7}; |
80 | // Float_t er1[3]={0.2,0.5,1.8}; |
81 | // Float_t r2[3]={8.6,23.8,-6.7}; |
82 | // Float_t er2[3]={0.93,1.78,0.8}; |
83 | // AliPosition begin,end; |
84 | // begin.SetPosition(r1,"car"); |
85 | // begin.SetPositionErrors(er1,"car"); |
86 | // end.SetPosition(r2,"car"); |
87 | // end.SetPositionErrors(er2,"car"); |
88 | // trec.SetBeginPoint(begin); |
89 | // trec.SetEndPoint(end); |
90 | // |
91 | // Note : All quantities are in GeV, GeV/c or GeV/c**2 |
92 | // |
93 | //--- Author: Nick van Eijndhoven 10-jul-1997 UU-SAP Utrecht |
94 | //- Modified: NvE 29-oct-1999 UU-SAP Utrecht |
95 | /////////////////////////////////////////////////////////////////////////// |
96 | |
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97 | #include "AliTrack.h" |
98 | |
99 | ClassImp(AliTrack) // Class implementation to enable ROOT I/O |
100 | |
101 | AliTrack::AliTrack() |
102 | { |
103 | // Default constructor |
104 | // All variables initialised to 0 |
105 | fDecays=0; |
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106 | fSignals=0; |
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107 | Reset(); |
108 | } |
109 | /////////////////////////////////////////////////////////////////////////// |
110 | AliTrack::~AliTrack() |
111 | { |
112 | // Destructor to delete memory allocated for decay tracks array |
113 | if (fDecays) |
114 | { |
115 | fDecays->Delete(); |
116 | delete fDecays; |
117 | fDecays=0; |
118 | } |
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119 | if (fSignals) |
120 | { |
121 | fSignals->Clear(); |
122 | delete fSignals; |
123 | fSignals=0; |
124 | } |
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125 | } |
126 | /////////////////////////////////////////////////////////////////////////// |
127 | void AliTrack::Reset() |
128 | { |
129 | // Reset all variables to 0 |
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130 | fQ=0; |
131 | fNdec=0; |
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132 | fNsig=0; |
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133 | Double_t a[4]={0,0,0,0}; |
134 | SetVector(a,"sph"); |
135 | if (fDecays) |
136 | { |
137 | fDecays->Delete(); |
138 | delete fDecays; |
139 | fDecays=0; |
140 | } |
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141 | if (fSignals) |
142 | { |
143 | fSignals->Clear(); |
144 | delete fSignals; |
145 | fSignals=0; |
146 | } |
147 | Double_t b[3]={0,0,0}; |
148 | fBegin.SetPosition(b,"sph"); |
149 | fEnd.SetPosition(b,"sph"); |
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150 | } |
151 | /////////////////////////////////////////////////////////////////////////// |
152 | void AliTrack::Set3Momentum(Ali3Vector& p) |
153 | { |
154 | // Set the track parameters according to the 3-momentum p |
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155 | Set3Vector(p); |
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156 | } |
157 | /////////////////////////////////////////////////////////////////////////// |
158 | void AliTrack::Set4Momentum(Ali4Vector& p) |
159 | { |
160 | // Set the track parameters according to the 4-momentum p |
161 | Double_t E=p.GetScalar(); |
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162 | Double_t dE=p.GetResultError(); |
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163 | Ali3Vector pv=p.Get3Vector(); |
164 | SetVector(E,pv); |
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165 | SetScalarError(dE); |
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166 | } |
167 | /////////////////////////////////////////////////////////////////////////// |
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168 | void AliTrack::SetMass(Double_t m,Double_t dm) |
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169 | { |
170 | // Set the particle mass |
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171 | // The default value for the error dm is 0. |
172 | Double_t inv=pow(m,2); |
173 | Double_t dinv=fabs(2.*m*dm); |
174 | SetInvariant(inv,dinv); |
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175 | } |
176 | /////////////////////////////////////////////////////////////////////////// |
177 | void AliTrack::SetCharge(Float_t q) |
178 | { |
179 | // Set the particle charge |
180 | fQ=q; |
181 | } |
182 | /////////////////////////////////////////////////////////////////////////// |
183 | void AliTrack::Info(TString f) |
184 | { |
185 | // Provide track information within the coordinate frame f |
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186 | Double_t m=GetMass(); |
187 | Double_t dm=GetResultError(); |
188 | cout << " *AliTrack::Info* Mass : " << m |
189 | << " error : " << dm << " Charge : " << fQ |
190 | << " Momentum : " << GetMomentum() << " Ntracks : " << fNdec |
191 | << " Nsignals : " << fNsig << endl; |
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192 | Ali4Vector::Info(f); |
193 | } |
194 | /////////////////////////////////////////////////////////////////////////// |
195 | void AliTrack::List(TString f) |
196 | { |
197 | // Provide current track and decay level 1 information within coordinate frame f |
198 | |
199 | Info(f); // Information of the current track |
200 | |
201 | // Decay products of this track |
202 | AliTrack* td; |
203 | for (Int_t id=1; id<=fNdec; id++) |
204 | { |
205 | td=GetDecayTrack(id); |
206 | if (td) |
207 | { |
208 | cout << " ---Level 1 sec. track no. " << id << endl; |
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209 | td->Info(f); |
210 | } |
211 | else |
212 | { |
213 | cout << " *AliTrack::List* Error : No decay track present." << endl; |
214 | } |
215 | } |
216 | } |
217 | /////////////////////////////////////////////////////////////////////////// |
218 | void AliTrack::ListAll(TString f) |
219 | { |
220 | // Provide complete track and decay information within the coordinate frame f |
221 | |
222 | Info(f); // Information of the current track |
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223 | cout << " Begin-point :"; fBegin.Info(f); |
224 | cout << " End-point :"; fEnd.Info(f); |
225 | for (Int_t is=1; is<=GetNsignals(); is++) |
226 | { |
227 | ((AliSignal*)GetSignal(is))->Info(f); |
228 | } |
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229 | |
230 | AliTrack* t=this; |
231 | Dump(t,1,f); // Information of all decay products |
232 | } |
233 | ////////////////////////////////////////////////////////////////////////// |
234 | void AliTrack::Dump(AliTrack* t,Int_t n,TString f) |
235 | { |
236 | // Recursively provide the info of all decay levels of this track |
237 | AliTrack* td; |
238 | for (Int_t id=1; id<=t->GetNdecay(); id++) |
239 | { |
240 | td=t->GetDecayTrack(id); |
241 | if (td) |
242 | { |
243 | cout << " ---Level " << n << " sec. track no. " << id << endl; |
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244 | td->Info(f); |
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245 | for (Int_t is=1; is<=td->GetNsignals(); is++) |
246 | { |
247 | ((AliSignal*)td->GetSignal(is))->Info(f); |
248 | } |
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249 | |
250 | // Go for next decay level of this decay track recursively |
251 | Dump(td,n+1,f); |
252 | } |
253 | else |
254 | { |
255 | cout << " *AliTrack::Dump* Error : No decay track present." << endl; |
256 | } |
257 | } |
258 | } |
259 | ////////////////////////////////////////////////////////////////////////// |
260 | Double_t AliTrack::GetMomentum() |
261 | { |
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262 | // Provide the value of the track 3-momentum. |
263 | // The error can be obtained by invoking GetResultError() after |
264 | // invokation of GetMomentum(). |
265 | |
266 | // Ali3Vector p=Get3Vector(); |
267 | // return sqrt(p.Dot(p)); |
268 | Double_t norm=fV.GetNorm(); |
269 | return norm; |
d88f97cc |
270 | } |
271 | /////////////////////////////////////////////////////////////////////////// |
272 | Ali3Vector AliTrack::Get3Momentum() |
273 | { |
274 | // Provide the track 3-momentum |
275 | return (Ali3Vector)Get3Vector(); |
276 | } |
277 | /////////////////////////////////////////////////////////////////////////// |
278 | Double_t AliTrack::GetMass() |
279 | { |
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280 | // Provide the particle mass. |
281 | // The error can be obtained by invoking GetResultError() after |
282 | // invokation of GetMass(). |
283 | Double_t inv=GetInvariant(); |
284 | Double_t dinv=GetResultError(); |
285 | Double_t dm=0; |
286 | if (inv >= 0) |
287 | { |
288 | Double_t m=sqrt(inv); |
289 | if (m) dm=dinv/(2.*m); |
290 | fDresult=dm; |
291 | return m; |
292 | } |
293 | else |
294 | { |
295 | cout << "*AliTrack::GetMass* Unphysical situation m**2 = " << inv << endl; |
296 | cout << " Value 0 will be returned." << endl; |
297 | fDresult=dm; |
298 | return 0; |
299 | } |
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300 | } |
301 | /////////////////////////////////////////////////////////////////////////// |
302 | Float_t AliTrack::GetCharge() |
303 | { |
304 | // Provide the particle charge |
305 | return fQ; |
306 | } |
307 | /////////////////////////////////////////////////////////////////////////// |
308 | Double_t AliTrack::GetEnergy() |
309 | { |
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310 | // Provide the particle's energy. |
311 | // The error can be obtained by invoking GetResultError() after |
312 | // invokation of GetEnergy(). |
313 | Double_t E=GetScalar(); |
314 | if (E>0) |
315 | { |
316 | return E; |
317 | } |
318 | else |
319 | { |
320 | cout << "*AliTrack::GetEnergy* Unphysical situation E = " << E << endl; |
321 | cout << " Value 0 will be returned." << endl; |
322 | return 0; |
323 | } |
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324 | } |
325 | /////////////////////////////////////////////////////////////////////////// |
326 | void AliTrack::Decay(Double_t m1,Double_t m2,Double_t thcms,Double_t phicms) |
327 | { |
328 | // Perform 2-body decay of current track |
329 | // m1 : mass of decay product 1 |
330 | // m2 : mass of decay product 2 |
331 | // thcms : cms theta decay angle (in rad.) of m1 |
332 | // phicms : cms phi decay angle (in rad.) of m1 |
333 | |
334 | fNdec=2; // it's a 2-body decay |
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335 | |
336 | Double_t M=GetMass(); |
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337 | |
338 | // Compute the 4-momenta of the decay products in the cms |
339 | // Note : p2=p1=pnorm for a 2-body decay |
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340 | Double_t e1=0; |
341 | if (M) e1=((M*M)+(m1*m1)-(m2*m2))/(2.*M); |
342 | Double_t e2=0; |
343 | if (M) e2=((M*M)+(m2*m2)-(m1*m1))/(2.*M); |
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344 | Double_t pnorm=(e1*e1)-(m1*m1); |
345 | if (pnorm>0.) |
346 | { |
347 | pnorm=sqrt(pnorm); |
348 | } |
349 | else |
350 | { |
351 | pnorm=0; |
352 | } |
353 | |
354 | Double_t a[3]; |
355 | a[0]=pnorm; |
356 | a[1]=thcms; |
357 | a[2]=phicms; |
358 | Ali3Vector p; |
359 | p.SetVector(a,"sph"); |
360 | |
361 | Ali4Vector pprim1; |
362 | pprim1.SetVector(e1,p); |
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363 | pprim1.SetInvariant(m1*m1); |
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364 | |
365 | Ali4Vector pprim2; |
366 | p*=-1; |
367 | pprim2.SetVector(e2,p); |
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368 | pprim2.SetInvariant(m2*m2); |
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369 | |
370 | // Determine boost parameters from the parent particle |
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371 | Double_t E=GetEnergy(); |
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372 | p=Get3Vector(); |
373 | Ali4Vector pmu; |
374 | pmu.SetVector(E,p); |
375 | |
376 | AliBoost q; |
377 | q.Set4Momentum(pmu); |
378 | |
379 | Ali4Vector p1=q.Inverse(pprim1); // Boost decay product 1 |
380 | Ali4Vector p2=q.Inverse(pprim2); // Boost decay product 2 |
381 | |
382 | // Enter the boosted data into the decay tracks array |
383 | if (fDecays) |
384 | { |
385 | fDecays->Delete(); |
386 | delete fDecays; |
387 | } |
388 | fDecays=new TObjArray(); |
389 | |
390 | fDecays->Add(new AliTrack); |
391 | ((AliTrack*)fDecays->At(0))->Set4Momentum(p1); |
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392 | ((AliTrack*)fDecays->At(0))->SetMass(m1); |
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393 | fDecays->Add(new AliTrack); |
394 | ((AliTrack*)fDecays->At(1))->Set4Momentum(p2); |
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395 | ((AliTrack*)fDecays->At(1))->SetMass(m2); |
396 | } |
397 | /////////////////////////////////////////////////////////////////////////// |
398 | Int_t AliTrack::GetNdecay() |
399 | { |
400 | // Provide the number of decay produced tracks |
401 | return fNdec; |
402 | } |
403 | /////////////////////////////////////////////////////////////////////////// |
404 | AliTrack* AliTrack::GetDecayTrack(Int_t j) |
405 | { |
406 | // Provide decay produced track number j |
407 | // Note : j=1 denotes the first decay track |
408 | if ((j >= 1) && (j <= fNdec)) |
409 | { |
410 | return (AliTrack*)fDecays->At(j-1); |
411 | } |
412 | else |
413 | { |
414 | cout << " *AliTrack* decay track number : " << j << " out of range." << endl; |
415 | cout << " -- Decay track number 1 (if any) returned." << endl; |
416 | return (AliTrack*)fDecays->At(0); |
417 | } |
418 | } |
419 | /////////////////////////////////////////////////////////////////////////// |
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420 | void AliTrack::AddSignal(AliSignal& s) |
421 | { |
422 | // Relate an AliSignal object to this track. |
423 | if (!fSignals) fSignals=new TObjArray(); |
424 | fNsig++; |
425 | fSignals->Add(&s); |
426 | } |
427 | /////////////////////////////////////////////////////////////////////////// |
428 | void AliTrack::RemoveSignal(AliSignal& s) |
429 | { |
430 | // Remove related AliSignal object to this track. |
431 | if (fSignals) |
432 | { |
433 | AliSignal* test=(AliSignal*)fSignals->Remove(&s); |
434 | if (test) |
435 | { |
436 | fNsig--; |
437 | fSignals->Compress(); |
438 | } |
439 | } |
440 | } |
441 | /////////////////////////////////////////////////////////////////////////// |
442 | Int_t AliTrack::GetNsignals() |
443 | { |
444 | // Provide the number of related AliSignals. |
445 | return fNsig; |
446 | } |
447 | /////////////////////////////////////////////////////////////////////////// |
448 | AliSignal* AliTrack::GetSignal(Int_t j) |
449 | { |
450 | // Provide the related AliSignal number j. |
451 | // Note : j=1 denotes the first signal. |
452 | if ((j >= 1) && (j <= fNsig)) |
453 | { |
454 | return (AliSignal*)fSignals->At(j-1); |
455 | } |
456 | else |
457 | { |
458 | cout << " *AliTrack* signal number : " << j << " out of range." << endl; |
459 | cout << " -- Signal number 1 (if any) returned." << endl; |
460 | return (AliSignal*)fDecays->At(0); |
461 | } |
462 | } |
463 | /////////////////////////////////////////////////////////////////////////// |
464 | void AliTrack::SetBeginPoint(AliPosition p) |
465 | { |
466 | // Store the position of the track begin-point. |
467 | fBegin=p; |
468 | } |
469 | /////////////////////////////////////////////////////////////////////////// |
470 | AliPosition AliTrack::GetBeginPoint() |
471 | { |
472 | // Provide the position of the track begin-point. |
473 | return fBegin; |
474 | } |
475 | /////////////////////////////////////////////////////////////////////////// |
476 | void AliTrack::SetEndPoint(AliPosition p) |
477 | { |
478 | // Store the position of the track end-point. |
479 | fEnd=p; |
480 | } |
481 | /////////////////////////////////////////////////////////////////////////// |
482 | AliPosition AliTrack::GetEndPoint() |
483 | { |
484 | // Provide the position of the track end-point. |
485 | return fEnd; |
486 | } |
487 | /////////////////////////////////////////////////////////////////////////// |